Rational management following diagnosis of myocardial ischemia

Assuming one knows that myocardial ischemia is present, rational management will first require a careful history to assess the severity of symptoms, such as angina, the lifestyle of the patient, his/her age, and the availability of resources. When a patient is ≥ 70 years, has little angina, even the demonstration of ischemia will not require early arteriography; pharmacological therapy on a trial basis is the preferred approach. Judging the response to oral nitroglycerine, isosorbide dinitrate, beta blockers and calcium antagonists, (often combined and in modest doses) is good rational management. If symptoms persist despite therapy or when the patient is younger and has symptoms which cannot be alleviated by changes in lifestyle and/or workload, the established ischemia assumes much greater significance and nearly always requires a coronary arteriogram for proper management. Once the coronary arteriogram has been analyzed in terms of severity of flow impairment, correlation with the tests showing the extent of myocardial ischemia must be made, best during exercise. If single vessel disease is found with a local dyskinetic (echo, scintigraphy, or angio) segment, which corresponds to a stenosis of ≥ 70%, particularly when found in the anterior descending artery, balloon dilatation (PTCA) or bypass surgery (CABG) should follow. When tests, such as the ECG, are obtained during an attack of angina, the Chahine classification may be used first. In Class II^a with pure ST-segment elevation significant atherosclerotic lesions are absent in most patients, while local spasm can be shown upon provocation. Here rational management can be limited to calcium antagonists sometimes combined with beta blockers. The same symptoms with ST-segment depression, rather than elevation, place the patient in Class II and II^b. These are usually associated with advanced stenosis in a multivessel form: when balloon dilatation cannot be executed, bypass surgery will have to follow. The above scheme applies equally well to the younger patients (≤ 55 years) with proven ischemia in whom symptoms are absent, but tests convincingly positive. Here the only difference with unstable angina lies in the timing - symptoms urge early intervention (days rather than weeks) -, while ischemia without symptoms allows time to schedule the intervention electively. Finally, if myocardial ischemia recurs after recovery from an episode of myocardial infarction, further complete investigation is nearly always required. In fact, this category of patient carries the highest risk, yet often goes undetected.