Ebook Practical cardiology (2nd edition) Part 2

C H A P T E R  5

THE
REVASCULARISATION
PATIENT
The rather grand term revascularisation refers to the use of coronary angioplasty or surgery to
improve myocardial blood supply.

Angioplasty
Balloon dilatation of coronary artery stenoses was first performed in the late 1970s by Andreas
Grunzig. The technique has undergone many refinements and is now widely used for the
treatment of angina not responding to medical treatment. Angioplasty has not been shown to
improve the prognosis of patients with stable angina. Coronary artery bypass grafting (CABG)
has similarly not been shown to prolong life for most stable angina patients. However, both treatments are very successful in relieving the symptoms of angina. The COURAGE Trial compared
optimal medical treatment of angina with angioplasty but excluded patients with symptoms
refractory to medical treatment.1 Not surprisingly, this group of stable mild angina patients had
a similar outcome with angioplasty and medical treatment. The trial suggests that compared
with optimal medical treatment, angioplasty is a safe and slightly more effective treatment for
stable angina. Patients can make an informed choice between these two treatments.
The majority of patients treated with angioplasty in Australia have acute coronary syndromes
and here there is good evidence of prognostic benefit with angioplasty compared with medical
treatment. In many centres one-, two- and complicated three-vessel disease are managed this
way. It has been shown to be as effective as coronary surgery for these patients but at the price
of a higher rate of re-intervention. This is because the greatest limitation of angioplasty is the
rate of restenosis in vessels that have been dilated.

Restenosis
Restenosis has been reported in as many as 40% of balloon angioplasties where a coronary
stent (p. 199) has not been used—plain old balloon angioplasty (POBA). Re-dilatation is usually possible but a similar risk of restenosis occurs after a second dilatation. Renarrowing of
these vessels is caused by the elastic recoil that occurs over the weeks after dilatation. POBA is
also associated with a relatively high risk of acute closure of the artery. This may result from

dissection of the arterial wall during dilatation, leading to thrombus formation or occlusion of
the vessel by the dissection flap.

Coronary stents
The introduction of coronary stents has revolutionised angioplasty (Fig 5.1). These folded metal
structures are crimped onto a balloon catheter. They are made from stainless steel or, more
recently, cobalt alloys. Alloy stents have thinner struts, which make them more flexible and may
reduce the rate of restenosis within the stent. Dilatation of the balloon expands the stent up
against the intima of the artery. The stent has enough radial strength to prevent elastic recoil.
It will also seal a dissection flap back into place. Dissection occurs when damage to the intima
separates it from the media. This can occur as a result of splitting of the intima following balloon
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a

b

c

Figure 5.1  (a) A drawing of a coronary stent during balloon dilatation (b) Stents crimped onto
their balloons (c) A model of an expanded stent

dilatation or from entry of the guide wire beneath the intimal layer. Blood enters the dissection
and forces the intima and media further apart. The use of stents has dramatically reduced the
complication rate of angioplasty. Dissection and acute closure of the vessel that would previously

have led to immediate coronary artery surgery can usually be repaired. Figure 5.2 and video
clips 20–22 show an example of dissection of the left main coronary artery.
The need for urgent coronary artery bypass grafting has fallen from about 5% of cases to
much less than 1%. In addition, more complicated lesions can be treated safely. Sometimes long
segments of arteries are stented (video clip 23), although at the cost of a higher risk of restenosis.
Numerous randomised trials have shown improvement in restenosis rates and in the need for
re-intervention when stents are used.2
Angioplasty is increasingly being performed in hospitals without cardiac surgical back-up.
There remains some controversy about this approach.

Bare metal stents
Although stents have eliminated the problem of elastic recoil, restenosis can still occur in up to
30% of patients. The mechanism of restenosis within a stent is different from that which occurs
after angioplasty. It has been shown that stents become lined with new endothelial cells within


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a

b

c

d

Guide wire
in circumflex

Figure 5.2  (a) This 55-year-old man was admitted for a routine angioplasty to a mid-LAD lesion
(arrow). He had exertional chest pain. The proximal LAD was calcified. (b) As the stent was
being positioned across the lesion, left main dissection caused by the guiding catheter became
apparent (arrow). This can be seen extending to the level of the first diagonal branch. The
patient had no symptoms. The origin of the circumflex was not compromised. (c) A guide wire
has been placed in the circumflex and a long stent is being positioned across the left main and
into the LAD (arrows). (d) The final result after stenting of the left main and the LAD and balloon
dilatation through the stent struts into the circumflex. A follow-up angiogram at six months
showed no restenosis and the patient was asymptomatic.

four weeks of being implanted. Some of these cells migrate through the struts of the stent from
the arterial media. For reasons not fully understood, in a proportion of patients they continue
to grow into the lumen of the vessel (neo-intimal proliferation) and gradually cause narrowing
that leads to a return of symptoms. This is rarely associated with an acute coronary syndrome
or infarct. This phenomenon occurs within six months of the stent insertion and it is rare for
restenosis to occur after this time. Although up to 30% of stents show evidence of restenosis, if
patients have routine follow-up angiograms only about 10% develop symptomatic restenosis.
Certain risk factors for restenosis have been identified (Table 5.1).


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Table 5.1  Risk factors for restenosis
1 Diabetes
2 Previous restenosis in that stent
3 A long lesion (and stent) (> 18 mm)
4 A narrow stent (< 3 mm)

5 Dilatation and stenting in a saphenous vein bypass graft
6 A stent not adequately dilated and deployed

Drug-eluting stents
The realisation that restenosis is a neoproliferative process has led to the development of drugeluting stents (DESs). These stents are coated with anti-proliferative drugs. The drug is held
within a polymer bonded to the metal. Drug elution occurs over about four weeks after implantation. The two drugs currently available are sirolimus and paclitaxel. Sirolimus is used for the
prevention of renal transplant rejection. It blocks G1 to S cell cycle progression. Paclitaxel is
an anti-proliferative agent that stabilises microtubules and prevents cell division. These drugs
have almost no systemic absorption when implanted with a stent.
The restenosis rate has been reduced dramatically by using these stents. Clinical restenosis
rates of 2% or 3% are commonly obtained. These stents are now implanted in 90% of angioplasty patients in the United States. In Australia the cost of these devices (four to five times that
of a bare metal stent) has kept the implantation rate much lower, but usage varies from state
to state. Cardiac surgeons note that the cost of CABG for a patient becomes less than that of
angioplasty once more than three or four drug-eluting stents are used.
In many hospitals DESs are reserved for patients with a high risk of restenosis. They have
not been shown to improve mortality compared with bare metal stents.

Alloy stents
There is some evidence that the thickness of the stent struts is a factor in the risk of restenosis.
Cobalt alloy stents have thinner struts and are more flexible than stainless steel ones. They can
be easier to deploy and may have a lower restenosis rate.

Bio-absorbable stents
Studies are underway with stents made of materials that are completely absorbed over a period
of months after implantation. These include magnesium stents.

Indications for angioplasty
Angioplasty is not indicated unless the lesion to be dilated is clearly the cause of the patient’s
symptoms, and then usually only if these have not responded to medical treatment. If a lesion
is of equivocal significance (< 50% stenosis) or the symptoms are atypical, a sestamibi test or

stress echo may be necessary to demonstrate ischaemia in the territory of the suspect vessel.
Angioplasty is a very effective treatment for stable angina but has not been proven to improve
prognosis when compared with intensive medical treatment. It may possibly do so when there
is three-vessel disease suitable for angioplasty or when the patient has a tight lesion in the left
anterior descending artery proximal to the first diagonal branch A lesion in this position that
threatens a large area of myocardium. Successful angioplasty should always be followed by
intensive risk factor modification.
Treatment of patients with ACS by angioplasty has been shown to improve outcomes,
including the risk of death and myocardial infarction (p. 157). In busy angioplasty units these
patients now provide the majority of the unit’s workload.


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Left main stem stenosis is increasingly being managed with angioplasty and stenting. There
remains some controversy about this approach. There is an incidence of sudden death in patients
treated in this way. This is quite a different outcome from the gradual return of angina that
occurs with restenosis in other vessels. In experienced centres the outcomes are as good as those
for CABG for left main stenosis.
The patient who has had bypass surgery and has some patent grafts to the circumflex or
LAD is an exception since the vessel is considered ‘protected’. Left main angioplasty is often
straightforward for these patients.

The technique
The balloon catheter is introduced using a coronary guiding catheter somewhat different from those
used for diagnostic angiography (Fig 5.3). Although diagnostic procedures are usually performed
with 5 French gauge catheters, angioplasty guiding catheters are often 6 or 7 French. They are
designed to provide back-up for the guide wire and balloon catheters—that is, to remain engaged in

the coronary ostium as catheters are passed into the artery. A fine guide wire is advanced through the
guiding catheter and into the coronary and across the lesion (Fig 5.4). A balloon dilatation catheter
is advanced along this wire until it crosses the lesion. The balloon is dilated with contrast solution
to a pressure of up to 18 atmospheres. The balloon is kept inflated for about 20 seconds (Fig 5.5).

Figure 5.3  A coronary angioplasty guiding catheter. This shape is designed for the left main
coronary and has the comforting name EBU, or extra back-up.
Lesion
Balloon
catheter

Guide wire

Figure 5.4  A coronary angioplasty balloon has been advanced to the lesion over its guide wire


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Since the vessel is completely occluded during the procedure, many patients experience
ischaemic chest pain and ST elevation may be visible on the ECG. The vessel is injected with
contrast and the effectiveness of the dilatation assessed.
A stent is chosen that is thought to be the correct diameter and length for the artery and
the lesion. Stents range in size from 2.25 mm diameter to 5.0 mm and in length from 8 mm to

a

b

Figure 5.5  (a) This 62-year-old man presented to the hospital with chest pain. His initial ECG
showed minor inferior ECG changes. Half an hour later his pain became more intense and his
ECG showed 3 mm of ST elevation in the inferior leads. He was transferred to the catheter
laboratory within 20 minutes of the onset of these ECG changes. The first picture taken showed
a totally occluded right coronary artery (arrow). (b) The balloon being inflated
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c

d

Figure 5.5—cont’d  (c) Right coronary artery now open after balloon dilatation of the occluded
segment. A ruptured plaque is visible at the point of occlusion. (d) Final result after stent
deployment: TIMI 3 flow


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about 38 mm. The longer the stent, the more difficult it may be to advance through a tortuous
or calcified artery to the lesion. The stent balloon is placed across the lesion and then inflated.
The nominal size of the stent will be reached when the balloon is inflated to the standard pressure
for that balloon. This is shown on a chart that comes with the balloon catheter. Dilatation to a
higher pressure will result in a larger expanded stent diameter. If the result looks unsatisfactory,

repeat dilatation (post-dilatation) can be performed with a higher pressure (non-compliant
balloon).
In some laboratories the lesion and stent expansion are assessed with IVUS (p. 137). Further
dilatation is performed if the stent struts do not seem adequately opposed to the vessel wall.

Closure devices
The femoral artery puncture site can be closed at the end of the procedure using a collagen
plug that is inserted into the artery by a sheath or by a stitch also deployed onto the puncture
via a sheath. This enables the patient to mobilise within an hour or two of the procedure, even
when aggressive anticoagulation and anti-platelet treatment have been employed. Otherwise,
the sheath is withdrawn some hours after the procedure when the ACT has fallen to about
150 seconds. Quite prolonged clamping of the site is often required and many patients find this
more of an ordeal than the procedure. Closure devices are expensive and for that reason are not
used for every patient in most hospitals.
If the procedure has been performed through the radial artery, the artery is compressed
with a velcro strap. Stable patients who have had an angioplasty performed via the radial
artery may sometimes be discharged on the same day; otherwise they are usually kept
­overnight.

Complications
All the risks associated with coronary angiography apply to the angioplasty procedure. Additional
possible complications include the following.

Dissection of the artery during balloon dilatation
or from the guiding catheter
In most cases stenting will close the dissection flap and lead to a very satisfactory outcome, but a
longer stent than would otherwise have been used may be required (Fig 5.2, video clips 20–22).
If dissection has been cause by the guide wire during attempts to cross the lesion, dissection
and the creation of a false lumen may make it impossible to wire and stent the true lumen
(Fig 5.6). Urgent coronary artery bypass grafting may be needed.

Perforation of the artery
This feared complication is most common when attempts are being made to cross a total
occlusion with a guide wire. Wires designed to cross chronically (more than six months)
occluded vessels are very stiff and can perforate the wall of the artery. Perforation by a wire
may cause only small amounts of bleeding into the pericardium, but if the perforation is not
recognised and a balloon is passed over the wire, torrential bleeding into the pericardium may
cause cardiac tamponade (p. 145) requiring urgent pericardiocentesis. The problem may be
compounded by the previous administration of IIb/IIIa inhibitors. A coronary perforation
or tear may be treated with a covered stent. This has a layer of gortex between two layers of
metal. If this rather bulky stent can be passed across the perforation, it will prevent further
bleeding.

No reflow
Dilatation of an artery or more often of a degenerated saphenous vein graft can dislodge clot or
atheromatous material further down the vessel. These fragments can occlude distal arterioles and
lead to poor flow into the distal bed and ischaemic symptoms (video clips 24–27). Treatment


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Figure 5.6  This 40-year-old man presented three days after the onset of ischaemic chest pain.
The ECG showed inferior T wave changes. The right coronary artery was totally occluded and
extensively thrombosed. Attempts to advance the guide wire led to extensive dissection of the
vessel and little blood flow. The wire was in a false lumen.

with vasodilators (nitroglycerine, adenosine or verapamil) may eventually restore flow. Various
devices have been developed to help prevent this problem, especially in vein graft angioplasties. These include occlusion balloons that can be inflated distal to the lesion. After dilatation

of the lesion a suction device is used to remove material before the balloon is deflated. Another
approach is to use a protection wire. These guide wires have a fine mesh basket attached to them.
This is opened beyond the lesion before dilatation and stenting are performed. It is removed
after it has been withdrawn into a fine catheter.

Side branch occlusion
Some of the most difficult angioplasties involve a lesion close to or involving a large (> 2 mm)
side branch. Dilatation of the main vessel risks shifting plaque into the branch and compromising it. Numerous techniques have been developed to deal with this problem. In many cases two
guide wires are used so that if dilatation of the main vessel narrows or occludes the origin of
the branch a balloon can be passed into the branch (Fig 5.7, video clip 23).
Simultaneous dilatation of two balloons (kissing balloons) may be necessary to keep both
vessels open. If, as is usual, the main vessel is stented the side branch needs to be re-wired
through the stent struts and dilatation into the side branch performed to open the struts and
the proximal part of the branch. Other techniques such as stenting the branch first or placing
stents into both vessels and dilating them simultaneously can be used. Whichever technique is
used, there is a higher risk of branch restenosis than for the main vessel. The ACT is measured
at the end of the case and additional heparin given if the level is less than about 300 seconds.


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Figure 5.7  Angioplasty of an LAD/first diagonal bifurcation lesion using two wires

Stent thrombosis
The thrombotic risk associated with the introduction of foreign material into the coronary artery
was at first managed with aggressive anticoagulation with heparin and then with warfarin. This
led to bleeding complications.

Dual anti-platelet therapy
Subacute stent thrombosis is now very uncommon. The use of two anti-platelet drugs (aspirin
and clopidogrel) in combination has been very effective in preventing stent thrombosis during
the peri-procedural period and afterwards.
Aspirin is a cyclo-oxygenase (COX-2) inhibitor and clopidogrel blocks ADP-dependent
platelet aggregation. Patients having a non-urgent angioplasty should be pre-loaded with both
drugs at least 24 hours before the procedure. Clopidogrel should be given as a loading dose of
300–600 mg (four to eight tablets) and then 75 mg a day, and the aspirin dose should be up to
300 mg a day.
Dual anti-platelet treatment should be continued for at least one month after bare metal
stent insertion and single anti-platelet treatment should be continued for ever. Patients who
receive a DES must continue dual anti-platelet treatment for at least six months, and two years
of treatment is now sometimes recommended. This is because re-endothelialisation is delayed
in these stents and thrombosis remains a risk for at least this period.

Late stent thrombosis
There are increasing (although rare) reports of late thrombosis in DESs (Fig 5.8). These are associated with a high incidence of myocardial infarction and death. They are often reported to have
occurred after single anti-platelet treatment has been stopped for some reason. Patients given
DESs should be warned that they must stop anti-platelet treatment only if absolutely necessary
(e.g. before surgery involving a high risk of bleeding) and for the shortest possible period.
DESs should be avoided for patients likely to need surgery within six months of the procedure
and for those who may not be compliant with their treatment.
Late stent thrombosis will be an area of intense research over the next few years. Since the
drug disappears from the stent within a month of implantation, theories as to the cause of late


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Figure 5.8  Thrombosis in a DES placed two years before in the LAD. The lucent area in the
centre of the vessel is due to thrombus (arrow). The patient presented with an acute anterior
infarct. Balloon dilatation in the thrombosed area (in combination with IIb/IIIa platelet inhibition)
led to a return of normal flow.

thrombosis and incomplete endothelialisation include concerns about the polymer on which
the drug is bound. Alternative ways of binding the drug to the stent are under investigation.

Adjuvant treatment
If the coronary plaque appears unstable or is associated with thrombus, more aggressive anti-platelet
treatment may be employed. The platelet glycoprotein IIb/IIIa inhibitor abciximab (Reopro) or
tirofiban (aggrastat) may be given intravenously at the time of ­angioplasty. This treat­ment seems
associated with a lower incidence of acute thrombosis and early closure. Patients are usually in
hospital overnight and may return quickly to their usual activities shortly after discharge.

The post-angioplasty visit
This is usually less complicated than the post-surgical visit. The patient should be asked how
things went. Possible problems include a large haematoma over the femoral artery and the recurrence of chest pain. Groin haematomas usually improve spontaneously but can sometimes be
spectacular and extend to the knee or even further. If there is a lot of discomfort and a pulsatile
lump is palpable over the puncture site there is the possibility of a pseudoaneurysm of the artery.
An ultrasound examination will confirm or eliminate this possibility. This is the only pathology
that ultrasonographers can cure as well as diagnose. The usual treatment is prolonged (an hour
or more) compression of the artery with a firm blunt object like an ultrasound probe. It is also
possible to inject a thrombin plug into the aneurysm and close it rather more quickly.


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The recurrence of pain may mean restenosis of the artery but atypical chest pain seems
common for a few weeks after angioplasty. An ECG should be performed, and if this shows no
changes expectant treatment may be all that is needed.
Early complications tend to involve thrombus and are associated with severe symptoms and
ECG changes. If there is further doubt an exercise test or even repeat angiography is sometimes
needed.
Restenosis is usually associated with the return of typical exertional angina three to six
months after the procedure (Fig 5.9). Although it can begin again quite suddenly, it is rarely
associated with infarction or death.

Figure 5.9  Severe stenosis inside an LAD stent. The patient had a return of angina but there
was no infarct despite the total occlusion of the artery.

Risk factors
The patient’s risk factors should be reviewed and treatment with aspirin continued indefinitely.
Patients with DESs must be reminded of the importance of their anti-platelet treatment.

Patients’ concerns
Patients may need to be reassured that the stent will not move and that it will become incorporated
into the vessel wall. It will not set off metal detectors. They can have MRI scans in the future, though
it is usual to recommend deferring these for a month from the time of implant. MDCT scanning
can be performed, though the lumen of a small stent may not be assessable because of flaring from
the metal. Patients do not need antibiotic prophylaxis before dental or surgical procedures.

Coronary artery surgery
Coronary artery bypass grafting may be recommended to patients whose angina cannot be
controlled by medical treatment (and who are not suitable for angioplasty)—that is, for symptoms. It is a most effective way of improving these patients and more than 90% will be free of


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angina and off anti-anginal drugs. Patients who have severe three-vessel disease and impaired left
ventricular function or who have significant left main stenosis (video clip 28) should be offered
surgery because it has been shown to improve their life expectancy and risk of infarction—that
is, for prognosis.3 Patients with severe proximal LAD stenosis may also have an improved
prognosis following revascularisation. In addition, all these patients are usually symptomatic
and will have their symptoms relieved.
Diabetics with multi-vessel disease have had a better outcome with surgery than with angioplasty.4 It is possible that the routine use of DESs in diabetics will change this outcome and this
is currently being tested in a multi-centre trial.5

The preoperative assessment
Surgery cannot be performed until a coronary angiogram has demonstrated the coronary
anatomy and that the arteries are suitable for grafting. In some cases severe disease of the distal
vessels may make it impossible for the surgeon to find a suitable area to attach the grafts and
surgery is not possible.
Other general medical problems may make surgery more difficult, more risky or impossible. It is not appropriate for patients with a poor life expectancy because of other medical
problems to be offered surgery. It is important that potential medical problems be identified
before surgery.
A history should be taken to find out particularly about previous renal disease, malignancy,
diabetes or lung disease. Patients need to be warned that continued smoking increases considerably the postoperative risk of chest infection and, of course, the risk of graft stenosis. Some cardiac
surgeons will decline to operate on patients who continue to smoke. Patients should be asked
about the presence of varicose veins or varicose vein surgery. Varicose veins cannot be used as
bypass grafts and the surgeon needs to be warned that alternative conduits have to be found.
The patient needs a physical examination where signs of severe airflow limitation may
indicate the need for further respiratory investigations before surgery. Varicose veins should
be looked for and their extent noted. The presence of carotid bruits is an indication for carotid
Doppler studies.
Routine investigations should include a blood count to exclude anaemia and serum electrolytes, and creatinine to exclude significant renal impairment. These problems need to be

addressed before surgery if they are uncovered. The patient may wish to avoid transfusion with
blood from the blood bank. Patients can be advised that only a small minority of patients now
need perioperative transfusion. It is usually preferable for the patient to be discharged from
hospital with moderate and usually well-tolerated anaemia (Hb of 80 or 90 g/L). In some cases,
if transfusion seems likely, it is possible for the patient’s blood to be stored by the blood bank
so that it can be used as required during surgery—autologous blood transfusion.
In general, patients continue with their usual medications up to the time of surgery. The
important exception is aspirin, which is often stopped several days before surgery because of
the bleeding problems it can cause in the perioperative period. Many cardiac surgeons are
now prepared to operate on patients who remain on aspirin. Patients with moderately severe
or unstable angina may be allowed to continue their aspirin, but dual anti-platelet therapy is
usually strongly discouraged by surgeons.

Surgery
Coronary artery bypass grafting involves the use of veins harvested from the legs (usually from the long
saphenous system), or arteries taken from the back of the chest wall (mammary arteries) (Fig 5.10)
or the arm (radial arteries). The chest is opened through a mid-line incision (median sternotomy).
The heart is arrested after the circulation is diverted through a heart–lung bypass machine.
If vein grafts are to be used, these are harvested from the legs. The proximal end is anastomosed to the ascending aorta and the distal end is anastomosed to one of the coronary arteries
beyond the stenosed area; the same vein may then be skipped to another coronary artery and
sometimes onto a third. In the majority of cases the left internal mammary artery (LIMA)


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a

Saphenous

vein
bypass
graft

b

Figure 5.10  (a) A patent saphenous vein graft, implanted six years previously. The patient had
return of angina and had new disease in an ungrafted right coronary artery. (b) A patent left
internal mammary artery graft in a different patient. The shape of the sternal wires is often a
surgeon’s signature, enabling him or her to recognise previous handiwork. 
Continues


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c

Figure 5.10—cont’d  (c) This patient’s X-ray resembles a metal scrap yard. Sternotomy wires,
arterial clips and two coronary stents (small arrows) are visible.

is used to bypass the left anterior descending coronary artery. The LIMA is left attached to
the left subclavian artery and carefully dissected off the back of the chest wall; the distal end is
anastomosed to the LAD beyond the diseased segment. Sometimes the LIMA is skipped to the
first diagonal branch of the LAD. The right internal mammary artery (RIMA) is sometimes
used to graft the right coronary artery. The radial artery can be used as a free graft. One end is
attached to the aorta and the other to the distal coronary.
Arterial grafts (LIMA, RIMA and probably radial free grafts) have the advantage of a low
restenosis rate. This is only 5–10% for LIMA grafts, after 10 years. Vein grafts have at least a

50% restenosis rate at 10 years. Arterial grafts are technically more difficult because the arteries
are very sensitive to handling and spasm can occur during or after surgery. This can lead to
ischaemia or infarction in the immediate postoperative period.
Recovery after coronary surgery takes longer than after angioplasty. Most patients are in
hospital for just under a week and can be back at work after four to eight weeks. The mortality
for uncomplicated patients is less than 1% but rises considerably if the operation is a second
bypass, the patient is diabetic or over 80, or left ventricular function is poor.

Management of graft stenosis
Sometimes dilatation and stenting can be performed to re-open narrowed grafts but the restenosis rate is high after angioplasty to degenerated vein grafts (Fig 5.11, video clips 29 and 30).
The procedure can be technically difficult and the mass of atheromatous material present
in these vessels is such that there is a risk of embolism to the distal vessels and ‘no reflow’
(p. 195). Severe graft disease, especially when the LAD graft is affected, is an indication for ‘redo’
coronary surgery. This procedure is becoming more common. It involves a higher risk than the
first operation and there may be technical problems with lack of adequate conduits (no veins
left, mammary already used) and with finding suitable ‘target vessels’ for the attachment of the
grafts. These patients are older and often have diffuse distal disease in their coronary arteries.


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a

b

c

Figure 5.11  (a) Severe stenosis (arrow) with little flow in an eight-year saphenous vein graft.

The patient was a 75-year-old man with recent severe angina. He had been symptom-free after
his surgery. (b) A guide wire and balloon have been advanced across the lesion. The balloon is
being inflated. (c) There is now normal flow in the graft and on into the native circulation.


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Minimally invasive coronary artery surgery is now being performed in some units. Thoracoscopic equipment is used so that bypass grafting can be performed through a series of
small, lateral thoracotomy incisions. Most commonly this involves grafting the LIMA to the
LAD coronary artery. The distal anastomosis can be performed on the beating heart and heart
bypass is not required. As yet the technique has limited application. The operation may take
longer than conventional surgery and the disposable equipment is very expensive. A series of
small lateral thoracotomies may cause more postoperative pain than a median-sternotomy and
hospital stay is not dramatically shortened. The distal anastomosis is difficult to perform and
long-term patency rates are not known.
‘Off-pump’ surgery can be performed on the beating heart. This avoids the possible complications of cardiopulmonary bypass (cognitive impairment, ventricular ischaemia) but can be
technically difficult. Newer techniques involving the use of left and right internal mammary arteries grafted off-pump and without the need to clamp the ascending aorta seem very promising.

Postoperative problems
The risks to the patient in the immediate recovery period include ischaemia or infarction because
of spasm or thrombosis of a graft. This may necessitate returning the patient to theatre for
regrafting. There are occasionally bleeding problems from a graft anastomosis which can also
mean re-operation. Hypotension or shock can occur because of cardiac ischaemia, hypovolaemia
or pre-existing cardiac failure. Inotropic support or even use of the intra-aortic balloon pump
(p. 281) may be required. This device is placed via the femoral artery into the descending aorta
and helps support the circulation.
Cardiac rhythm disturbances are common following surgery. Atrial fibrillation may occur
in up to 30% of patients and for up to a month after the operation. In many units digoxin or

sotalol (p. 228) is given routinely after surgery and for about a month after discharge. These
drugs are used to prevent rapid ventricular response rates for patients who develop atrial fibrillation and, in the case of sotalol, to prevent AF. Preoperative amiodarone has been shown to
reduce the postoperative risk of AF.6
Respiratory complications are also common, especially for patients who have been smokers.
Areas of atelectasis occur in most patients and improve gradually over a period of weeks. Constant physiotherapy and breathing exercises are needed to prevent larger areas of lung collapse.
This susceptibility is due to the discomfort of deep breathing caused by the chest wound and
the fact that the lungs have been deflated during surgery.
Wound infection is a relatively uncommon problem. It is perhaps more common in the vein
harvesting wounds. Small areas of infection may require only the removal of a suture and a
course of antibiotics and dressings. Larger areas of wound breakdown may mean leaving the
wound open and allowing slow healing by secondary intention. Sternal wound infections may
be slight and need only dressing and drying out with iodine ointments. Severe sternal wound
infections, however, can be a disaster since there are foreign bodies (the sternal wires) present.
Long courses of intravenous antibiotics and eventual removal of the wires may be needed.

The postoperative visit
The clinician should express pleasure but not surprise at seeing the patient returned home from
hospital. Questions should be asked about the procedure from the patient’s point of view.
The patient should be asked whether there has been any angina and how uncomfortable
the chest and leg wound have been. The clinician should find out whether there is a productive
cough or any sign of wound infection. There may have been problems with dyspnoea suggesting the possibilities of chest infection, cardiac failure or occasionally pulmonary embolism or
pericardial or pleural effusion. The clinician should also ask whether the patient’s analgesic
regimen has been adequate especially to allow sleep.
The list of medications should be studied. It is likely to include aspirin, analgesics, any previous
anti-hypertensive drugs, iron supplements and possibly digoxin, sotalol or amiodarone. Depending on the surgeon’s degree of self-confidence the patient’s previous anti-anginal drugs may or


5 •  T H E R E V A S C U L A R I S A T I O N P A T I E N T

205

may not have been stopped. If there has been no chest pain suggestive of angina, anti-anginal
drugs should be stopped. Anti-arrhythmic drugs and iron supplements are usually continued for
about a month. Aspirin should be continued indefinitely and the opportunity to talk to the patient
about risk factor control should not be lost. Reminders about smoking cessation if appropriate
and a low-fat diet should be given. The serum cholesterol is likely to be lower than usual for the
patient during the first couple of months after surgery, but arrangements to check it a few months
later should be made. All patients will qualify for secondary prevention treatment with a statin.
The routine examination should include inspection of the wounds, looking for signs of chest
infection or pleural effusion (bronchial breathing or areas of stony dull percussion note at one
or both lung bases). Examination of the cardiovascular system may reveal atrial fibrillation, high
or low blood pressure, signs of cardiac failure (p. 258) or a pericardial rub.
An ECG should be performed. Widespread T wave changes are common after surgery for up
to a few months. The presence of new Q waves suggests a perioperative infarction. The patient
may be in atrial fibrillation. The late development of this, especially in patients not protected
by an anti-arrhythmic drug, can be a cause of dyspnoea and cardiac failure.
A chest X-ray is required if there is concern about lung pathology, cardiac failure or a pericardial collection. An increase in heart size suggests the need for an echocardiogram to assess left
ventricular function and look for a pericardial collection. Small pleural and pericardial effusions
are common and usually resolve spontaneously, but large ones may need to be drained.

Cardiac rehabilitation
This is just as useful for patients recovering from surgery as for those who have suffered an
infarct. In addition to an exercise program and information about risk factors, advice about
management of wound problems and chest physiotherapy can be given.

The revascularisation patient: points to remember
1 G
 ood preoperative assessment may prevent postoperative complications or
delay in surgery or angioplasty.
2 Review of the patient’s medications is appropriate.

3 Angioplasty patients with coronary stents (most of them) must have dual antiplatelet treatment for at least a month (BMS) or at least six months (DES).
4 Long-term low-dose aspirin is also indicated for CABG patients.
5 The postoperative visit is an important opportunity to reassess risk factors. All
revascularisation patients need appropriate treatment for secondary prevention.


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CAS E - BAS ED LEARNING : I S CH AEM IC HEART DISEA SE—
RE V A S CULARI S ATION
A patient is seen in general practice after being discharged from hospital following a coronary
angiogram. This was performed after referral to a cardiologist because of increasing exertional
chest heaviness and dyspnoea.
Mrs CS is a 70-year-old with a long history of ischaemic heart disease. She had an inferior
infarct eight years ago and after investigations was treated medically. She has been a type
2 diabetic for six years, treated with oral hypoglycaemic drugs. Her HbA1c averages 8. She has a
history of hypertension, treated with an ACE inhibitor with only reasonable control (145/80).
Her cholesterol when last checked was 8.0 mmol/L; her triglycerides are 3.5 mmol/L. Although
prescribed a statin she is reluctant to take it because she thinks she saw a report that these drugs
cause memory loss. She smoked until the time of her infarct. She does not take aspirin because
she is concerned it might cause gastric ulceration.
She has been told she has disease in all three of her coronary arteries and that her heart muscle
has been damaged by her previous myocardial infarction. Her cardiologist has told her she could
have either cardiac surgery or angioplasty and asks her to decide what she wants done.

Objectives for the group to understand
The group needs to develop an understanding of the indications for coronary revascularisation
and the place of risk factor management for patients undergoing either surgical or interventional

revascularisation.

Epidemiology and population health
The presenter should ask questions about coronary artery disease epidemiology, including the
important risk factors (Ch 1 and 2), disease prevalence and typical age of onset. The importance
of combinations of risk factors and of previous ischaemic heart disease as a risk factor should
be identified. The influence of diabetes on risk and on future management must be discussed.
What might have been done to reduce the risk of progression of her coronary disease after her
first infarct?

Presenting symptoms and clinical examination
The group should discuss the features of ischaemic chest pain and compare the characteristics
of pain due to myocardial infarction and other ACSs with those of angina. Are the symptoms
Mrs CS has typical of angina? A differential diagnosis of chest pain should be drawn up by the
group (p. 176).

Review of pathophysiology
The presenter should ask questions about the difference in pathophysiology of stable angina
and the ACSs. The group should know how the coronary anatomy (i.e. the extent and severity
of coronary disease) correlates with symptoms and prognosis.

Evidence-based practice relevant to case
The group should discuss the role and method of risk stratification based on the coronary
anatomy and assessment of left ventricular function. Which is more important as an indicator
of prognosis?
The presenter should ask for opinions on the role of revascularisation for patients with stable
angina. Which patients benefit in terms of their prognosis from cardiac surgery and which get
only symptom relief (CASS study)? What is the evidence for more aggressive risk factor control
for the future (cholesterol, triglycerides, blood pressure, BSLs)?

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207

What is the evidence supporting the use of coronary artery surgery compared with multivessel angioplasty (ARTS Trial) with or without DESs, and in diabetics compared with
non-diabetics?
What is the place of anti-platelet therapy for patients with stable angina and for patients
following cardiac surgery? Which agent should be used (CAPRIE Trial)? When is dual antiplatelet therapy appropriate?
The group should be aware of the major trials of these treatments.
Mrs CS’s physical examination
On examination Mrs CS has a BMI of 30. She is not breathless undressing. Her blood pressure
is 170/90 mmHg, and her pulse 85. The apex beat is not palpable. Her heart sounds are normal.
Her chest is clear. She has a small non-tender bruise over the right femoral artery puncture site.
There are varicose veins in her left leg and thigh; the right side appears normal.
Her ECG shows an old inferior infarct and some anterior T wave flattening.

Diagnostic pathology
The presenter should get the group’s opinion about the adequacy of the investigations so far.
Does this history, ECG and angiogram information provide enough evidence for the recommendation of intervention? Is there a place for further tests (e.g. sestamibi scanning or calcium
scoring)?
Mrs CS’s prognosis
Mrs CS says she would rather not have angioplasty or surgery. She would like to know whether
there are medical options for her treatment. What would the group tell her? What medical
treatment might relieve her symptoms? What might improve her prognosis?
Is there evidence to support an attempt to persuade Mrs CS to have surgery or angioplasty?
How would the group explain the advantages and disadvantages of each?
What is the relevance of her varicose veins?

Personal and professional development

and medico-legal aspects
The group should discuss the clinician’s place in advising a reluctant patient about drugs or
other treatment that may improve prognosis. What is the place of the clinician or specialist in
explaining the risks associated with procedures and surgical operations? How do the results of
trials relate to the treatment of individual patients?

Therapeutics
Mrs CS decides she wants to have a trial of medical treatment even though she has been told
surgery would have prognostic benefits for her. She is begun on metoprolol 50 mg bd, ceruvostatin 10 mg daily and aspirin. Her diet is reviewed by a dietician and her oral hypoglycaemic
medication is increased. She promises to test her blood sugars twice a day.
After six weeks she has lost 4 kg, her blood sugars average 7 and her blood pressure is
135/85 mmHg. Her exercise tolerance has improved slightly. She can walk at her own pace on
the flat but has to pause and use sublingual nitrates when she walks uphill.
What would the group advise? Can Mrs CS expect further improvement if she perseveres?
After a family conference Mrs CS decides to have cardiac surgery. She spends eight days in
hospital. She has quadruple bypass—an internal mammary graft to the left anterior descending
coronary artery, a saphenous vein graft to the circumflex and first diagonal branch of the LAD,
and a radial graft to the right coronary artery. There is a small problem with infection in her
vein harvesting wound but her stay is otherwise uncomplicated.
What should be reviewed at her first outpatient visit?
1 Symptoms—angina, dyspnoea, palpitations
2 Wound problems


208

3
4
5
6

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PRACTICA L C A R D I O L O G Y

 edications—usual and anti-arrhythmic
M
Mobility and ability to cope with activities of daily living
Involvement in rehabilitation program
Driving
Follow-up appointments with surgeon, cardiologist and clinician

Psychosocial aspects
The presenter should ask for comment on the role of the medical and nursing staff in helping
patients to recover their confidence after this major surgery. Patients often have periods of
alternating depression and euphoria for six or eight weeks after cardiac surgery.
What advice should be given about the timing of return to work and sexual activity?
Should a patient be encouraged to join a cardiac rehabilitation program? Is there evidence
of such a program’s usefulness (p. 176)?
Mrs CS’s long-term management
What would be the group’s approach to the long-term management of Mrs CS with particular
reference to her risk factors—her diabetes, weight, cholesterol and hypertension? What is her
prognosis and risk of a further ischaemic event with and without aggressive risk factor control?
What is the natural history of bypass grafts, and how do vein grafts compare with internal
mammary or radial grafts as far as their long-term patency is concerned?

Research
Are there any aspects of the patient’s management that lack an appropriate evidence base? If
so, how can these deficiencies in knowledge be addressed by research? What research is being
conducted comparing angioplasty with surgery for patients with three-vessel disease? n

End notes
1 C
 OURAGE Trial investigators. Optimal medical therapy with or without PCI for stable coronary
disease. New Eng J Med 2007; 356:1503–1516.
2 Serruys P, de Jaegere P, Kiememieij F, et al. A comparison of balloon expandable stent implantation with balloon angioplasty in patients with coronary artery disease. New Eng J Med 1994; 8:489
(Benestent Trial).
3 CASS study.
4 ARTS Trial.
5 FREEDOM Trial.
6 Budeus M, Hennersdorf M, Perings S, et al. Amiodarone prophylaxis for atrial fibrillation of highrisk patients after coronary artery bypass grafting: a prospective, double-blinded, placebo-controlled,
randomised study. Eur Heart J 2006; 27:1584–1591.
.

.

.

.

.

.


C H A P T E R  6

THE PATIENT WITH
PALPITATIONS
The history
Palpitations are perhaps best defined as an inappropriate awareness of the heart’s beating. It is

not really a medical term but patients often feel that use of the word to describe their symptoms
should be enough to give the clinician the diagnosis. Taking the history from patients who
complain of palpitations may therefore be difficult, as patients may resent having to describe
their symptoms in more detail.
The first questions should be directed at finding out what the patient actually means and
whether there is really an awareness of the heart beating or some quite different symptom. Ask
the patient to describe what happens and assess whether the abnoise tolerance is usually maintained into adult life for most patients but
progressive deterioration then occurs. Haemorrhagic complications, especially haem­optysis,
are common. Thrombotic stroke, cerebral abscess and pulmonary infarction can also occur.


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PRACTICA L C A R D I O L O G Y

In a recent European survey, survival for patients with simple defects and Eisenmenger’s
was to 32.5 years, but only 25.8 years for those with Eisenmenger’s resulting from complex
abnormalities.38
There is a 50% maternal mortality risk with pregnancy. Quite minor surgical ­procedures
are associated with high risk.
Trials with endothelin antagonists are being conducted and continuous oxygen treatment can provide symptomatic relief. Lung and heart lung transplant should be considered
for some of these patients.
6 Endocarditis. Most patients with congenital heart disease have a lifelong risk of infective
endocarditis. Constant reminders of this risk should be given to the patients and their usual
doctors. As well as appropriate antibiotic prophylaxis (p. 325) before procedures, a high
index of suspicion is very important. A febrile illness should not be treated with antibiotics
until at least two sets of blood cultures have been taken. Early referral to a specialised unit
and investigations such as transoesophageal echocardiography are important.
Some of the more common abnormalities are discussed below.

Fallot’s tetralogy
This is a common abnormality and there are many adult survivors who have repair operations
in infancy or childhood.

Anatomy and physiology
The four features of the tetralogy are:
1 a large and unrestrictive VSD (no pressure gradient across the defect)
2 malalignment of the aortic root so that it overrides the defect
3 right ventricular outflow obstruction (this is usually infundibular but can involve the
­pulmonary valve)
4 right ventricular hypertrophy (secondary to the outflow obstruction) (Fig 9.5).

AO

PA
Overriding aorta

Infundibular
stenosis of PV
VSD

LV

RV hypertrophy

Figure 9.5  Fallot’s tetralogy: (1) VSD; (2) overriding aorta; (3) right ventricular outflow
obstruction; (4) right ventricular hypertrophy


9 • O T H E R P R O B L E M S

365

There is variable right to left shunting across the defect (and thus variable cyanosis) depending
on the degree of outflow obstruction from the right ventricle. This obstruction tends to increase
as the baby grows. There is protection against pulmonary hypertension because of the outflow
obstruction or pulmonary valve stenosis.

Surgical treatment
Corrective surgery is carried out in childhood and consists of closure of the VSD and repair of
the outflow obstruction. Residual obstruction and pulmonary regurgitation can be problems
after surgery.

Follow-up
The prognosis is usually excellent. Patients may have problems with right ventricular function.
Regular review and echocardiography are usually indicated. Atrial arrhythmias are relatively
common and complete heart block can be a late complication. There is a small incidence of
sudden death from ventricular arrhythmias.

Further treatment
Persistent outflow tract or more distal pulmonary stenosis, VSD or aortic stenosis can be reasons
for re-intervention.

Pregnancy
There is no contraindication to pregnancy for successfully treated patients.

Sports
After successful surgery patients can exercise normally unless there have been ventricular
arrhythmias.

Ebstein’s anomaly
Anatomy and physiology
This uncommon abnormality is due to abnormal positioning of the tricuspid valve. The
septal leaflet is placed well below its usual position on the right ventricular side of the
ventricular septum (Fig 9.6). The valve is usually incompetent and tricuspid regurgitation
of variable severity is present. In 50% of cases there is an ASD. When tricuspid regurgitation is severe, the right atrial pressure is increased above that of the left atrium, and right
to left shunting and cyanosis occur. The right ventricle is small and the right atrium is
large because part of the right ventricle lies above the tricuspid valve and forms part of
the atrium.
The severity of the condition is very variable and depends on the position of the septal leaflet,
the severity of the regurgitation and the presence of an ASD. Severe cases lead to inter-uterine
death; mild ones may not be diagnosed until adult life.

Complications
Patients may be cyanosed, have signs of tricuspid regurgitation and on auscultation the
characteristic finding is of multiple systolic clicks. Symptomatic patients should be offered
surgery to repair the valve and close the ASD. Valve replacement is an option if repair is not
possible.
Atrial arrhythmias are common in adult life and there is a risk of sudden death. Pre­excitation and associated re-entrant tachycardia are common.

Follow-up
Echocardiography will allow assessment of the severity of the valvular displacement and tricuspid regurgitation. Frequency of review depends on the severity, but regular echocardiography
is usually indicated.


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PRACTICA L C A R D I O L O G Y

Right atrium

Left atrium

Atrialised
portion of
RV

Downward
displacement
of septal leaflet

RV

Tricuspid
regurgitation

LV

Figure 9.6  Ebstein’s anomaly. The septal leaflet of the tricuspid valve is placed below its normal
position. The right atrium is large and there is usually tricuspid regurgitation present.

Treatment
In adults surgery is indicated when exertional dyspnoea becomes a problem. Radiofrequency
ablation may be required for re-entrant tachycardia.

Pregnancy
Pregnancy is well tolerated unless there is cyanosis or heart failure. Fetal loss is high if there is
maternal cyanosis.

Sports

Non-competitive sport is allowed for asymptomatic patients.

Atrioventricular canal (endocardial cushion) defects
Anatomy and physiology
During the development of the heart a number of structures form from the endocardial
cushion region of the heart tube. These include the AV (i.e. mitral and tricuspid) valves and
the lower atrial septum and membranous ventricular septum. Abnormal development results
in a range of defects affecting these structures. A partial AV canal defect usually means an
ostium primum ASD and a cleft in the anterior mitral valve leaflet. An ostium primum defect
involves the lower atrial septum. An ostium secundum defect (the more common type) is
not a canal defect and involves the central portion of the septum. A complete defect means a
large membranous VSD, an ostium primum ASD and a single AV valve. Complete AV canal
defects are particularly common in patients with Down syndrome, occurring in up to 20%
of these people (Fig 9.7).

Complications
The clinical picture varies and depends on the amount of left to right shunting and the severity
of the AV valve regurgitation. There are often signs of right ventricular overload and mitral
regurgitation. Most cases are identified in infancy or childhood. Without corrective surgery