Does angioplasty need on site surgical cover? A surgeon's view.

Though angioplasty is an established technique for the management of coronary artery disease, there is still controversy about whether it needs on site surgical cover. The aims of angioplasty and coronary artery bypass surgery in the management of coronary disease are similar, namely to relieve symptoms and in certain groups to improve prognosis, at the lowest risk and morbidity. Because the development of myocardial damage during both procedures significantly reduces long term survival, treatment strategies must not be based on short term results. Myocardial damage at the time of intervention and subsequently is important. The principal risk of angioplasty is the development of acute myocardial ischaemia progressing to infarction owing to vessel occlusion with or without dissection. Increasing technical skills and improved equipment may reduce these complications but vessel occlusion is likely to remain the chief immediate complication of angioplasty. The most reliable data on the true incidence. of complications of angioplasty are more likely to come from registers than from individual hospitals. In the United States, the Second Generation 1985/6 Percutaneous Trans-d luminal Coronary Angioplasty Register of the National Heart, Lung and Blood Institute (incorporating 1801 patients) showed a vessel occlusion rate of 4 9%, an emergency coronary artery bypass rate of 3 5%, a non-fatal myocardial infarction rate of 4 3%, and an inhospital mortality of 1% (varying from 0 2% for single vessel disease to 2 2% for triple vessel disease).' The French registry for 1987 reviewed 2700 patients and recorded a 21% infarction rate, a 107% urgent surgery rate, and 0-90 mortality.2 Not all patients in whom vessel occlusion develops need either further angioplasty or emergency surgery, particularly if there is no evidence of myocardial ischaemia or if the occluded vessel is very small. A further group of patients will have been advised to have angioplasty rather than surgery because disease in other organs puts them a higher sur-. gical risk and in such patients a myocardial infarction may be the less dangerous option. Clearly defined treatment strategies should be developed to prevent or limit myocardial damage once vessel occlusion occurs and there is evidence of myocardial ischaemia. Prompt action is required and the best solution is one achieved immediately by the angioplasty operator-but such attempts are successful in only about 50% of patients and are still associated with a considerable risk of myocardial infarction. More extended use of techniques such as autoperfusion dilatation catheters, stents, laser welding, or arthrectomy devices3 might reduce the need for emergency surgery, but they remain experimental. For patients who are haemodynamically unstable, the use of an intra-aortic balloon pump or percutaneous cardiopulmonary bypass may help to stabilise their condition but should not delay surgical intervention. Given that surgery is important in the mangement of complications of angioplasty, how close should the operating theatre be to the catheterisation laboratory? It is important to plan for the worst outcome-which is cardiac arrest requiring continuing cardiopulmonary resuscitation. Once vessel occlusion and myocardial ischaemia have occurred and it is clear that further angioplasty techniques have failed, most patients should be transferred to the operating theatre as soon as possible. The effect of the length of the interval from occlusion to surgical revascularisation on subsequent infarction is not clear, largely because it is a non-homogeneous population; however, in large series rates of myocardial infarction in patients requiring emergency surgery varied from 11%,0 to 46% ." Furthermore, the extent of the infarction as well as its occurrence is important and the evidence of the effects of time to reperfusion from studies of thrombolysis indicates the need for rapid intervention. In a series of 4142 patients in Eindhoven of whom 155 required emergency surgery, five were taken to theatre in cardiac arrest and 19 in cardiogenic shock and were revascularised St George's Hospital, London D John Parker