Free Examination Medicine: A Guide to Physician Training by Nicholas J. Talley, Simon O’connor Page A
Authors: Nicholas J. Talley, Simon O’connor
pulse may be absent. More general complications include a stroke owing to embolism from the heart.
Management
It is best to concentrate on discussing the management of the presenting problem. If the patient has only recently been admitted with an infarct, this means a discussion of thrombolysis and primary angioplasty.
1. Candidates should have some knowledge of the major thrombolysis and angioplasty trials.
a. These have shown that early treatment has improved mortality. Treatment up to 12 hours after the onset of an infarct is worthwhile.
b. The indications and contraindications to the use of these techniques need to be well understood. The major differences between streptokinase and the fibrin-specific drugs (tPA (alteplase) or reteplase) are important. Streptokinase is much cheaper. Alteplase and reteplase have been shown to produce a small survival advantage, probably because they are more effective in opening occluded vessels, but have a slightly increased risk of causing cerebral haemorrhage. Alteplase is the drug of choice for patients who have had a previous dose of streptokinase more than a few days before. This is because antibodies to streptokinase develop within a few days and may cause an allergic reaction to a second dose, thus reducing its effectiveness.
c. Alteplase is given as a bolus followed by an infusion, and reteplase is given as a double bolus injection with a 30-minute interval. Even when thrombolysis seems successful (resolution of symptoms and ST depression) patients are now routinely transferred so that angiography can be performed as soon as practical.
2. Urgent coronary (primary) angioplasty, if available, is of proven benefit and has been shown to reduce mortality compared with treatment with thrombolytic drugs.
a. The advantages, theoretical and real, include definite re-opening of the infarct-related artery in more than 90% of patients (compared with <60% of patients given thrombolytics), normal flow in the infarct-related artery in most cases, dilatation and stenting of the offending (culprit) lesion and often removal of clot, very low risk of stroke and shortening of hospital stay, often to only 3 days.
b. Patients are treated with potent anti-platelet drugs: aspirin, clopidogrel (or prasugrel or ticagrelor) and sometimes with one of the platelet aggregation inhibitors, abciximab or tirofiban. Prasugrel is more rapidly effective than clopidogrel and inmany protocols is now preferred for primary angioplasty patients. Ticagrelor may improve prognosis compared with the other drugs. Its most common side-effect is dyspnoea, which may develop after 5–10 days.
c. There is now trial evidence that transport of patients to a hospital where this procedure can be performed is preferable to treatment with thrombolytic drugs, if transport time is less than 2–3 hours.
d. Rapid transport to the catheter laboratory is important and the ‘door to balloon’ time should be less than 90 minutes when angioplasty is available in the hospital to which the patient presented.
3. If the history has suggested complications resulting from the infarct, these will have to be discussed. Common complications include:
• ventricular arrhythmias
• bradyarrhythmias (especially following an inferior infarct)
• cardiac failure
• further ischaemia or reinfarction.
It is important to have planned an approach to the management of these problems.
Investigations
These are aimed at assessment of the infarct size, complications and presence of further ischaemia:
1. left ventricular function – echocardiogram, left ventriculogram
2. complications – echocardiogram for valvular regurgitation, left ventricular thrombus, infarct-related VSD
3. further ischaemia – exercise test, sestamibi stress test, cardiac catheterisation
4. viability – MRI scan, sestamibi scan.
Long-term treatment
1. Early revascularisation is of proven benefit for high-risk patients with acute
Management
It is best to concentrate on discussing the management of the presenting problem. If the patient has only recently been admitted with an infarct, this means a discussion of thrombolysis and primary angioplasty.
1. Candidates should have some knowledge of the major thrombolysis and angioplasty trials.
a. These have shown that early treatment has improved mortality. Treatment up to 12 hours after the onset of an infarct is worthwhile.
b. The indications and contraindications to the use of these techniques need to be well understood. The major differences between streptokinase and the fibrin-specific drugs (tPA (alteplase) or reteplase) are important. Streptokinase is much cheaper. Alteplase and reteplase have been shown to produce a small survival advantage, probably because they are more effective in opening occluded vessels, but have a slightly increased risk of causing cerebral haemorrhage. Alteplase is the drug of choice for patients who have had a previous dose of streptokinase more than a few days before. This is because antibodies to streptokinase develop within a few days and may cause an allergic reaction to a second dose, thus reducing its effectiveness.
c. Alteplase is given as a bolus followed by an infusion, and reteplase is given as a double bolus injection with a 30-minute interval. Even when thrombolysis seems successful (resolution of symptoms and ST depression) patients are now routinely transferred so that angiography can be performed as soon as practical.
2. Urgent coronary (primary) angioplasty, if available, is of proven benefit and has been shown to reduce mortality compared with treatment with thrombolytic drugs.
a. The advantages, theoretical and real, include definite re-opening of the infarct-related artery in more than 90% of patients (compared with <60% of patients given thrombolytics), normal flow in the infarct-related artery in most cases, dilatation and stenting of the offending (culprit) lesion and often removal of clot, very low risk of stroke and shortening of hospital stay, often to only 3 days.
b. Patients are treated with potent anti-platelet drugs: aspirin, clopidogrel (or prasugrel or ticagrelor) and sometimes with one of the platelet aggregation inhibitors, abciximab or tirofiban. Prasugrel is more rapidly effective than clopidogrel and inmany protocols is now preferred for primary angioplasty patients. Ticagrelor may improve prognosis compared with the other drugs. Its most common side-effect is dyspnoea, which may develop after 5–10 days.
c. There is now trial evidence that transport of patients to a hospital where this procedure can be performed is preferable to treatment with thrombolytic drugs, if transport time is less than 2–3 hours.
d. Rapid transport to the catheter laboratory is important and the ‘door to balloon’ time should be less than 90 minutes when angioplasty is available in the hospital to which the patient presented.
3. If the history has suggested complications resulting from the infarct, these will have to be discussed. Common complications include:
• ventricular arrhythmias
• bradyarrhythmias (especially following an inferior infarct)
• cardiac failure
• further ischaemia or reinfarction.
It is important to have planned an approach to the management of these problems.
Investigations
These are aimed at assessment of the infarct size, complications and presence of further ischaemia:
1. left ventricular function – echocardiogram, left ventriculogram
2. complications – echocardiogram for valvular regurgitation, left ventricular thrombus, infarct-related VSD
3. further ischaemia – exercise test, sestamibi stress test, cardiac catheterisation
4. viability – MRI scan, sestamibi scan.
Long-term treatment
1. Early revascularisation is of proven benefit for high-risk patients with acute
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