Unstable angina pectoris: pathogenesis and management

Unstable angina is a simple term used to describe a complex group of conditions with a heterogeneous pathogenesis and prognosis. In patients with cardiac disease, understanding pathogenetic mechanisms often influences decisions regarding prognosis and treatment. Potential causes for the development of acute myocardial ischemia include: 1. Extracardiac factors in the patient with severe coronary atherosclerosis. 2. Plaque disruption resulting in: a. Transient platelet aggregation in diseased vessels. b. Dynamic or intermittent coronary artery thrombosis. c. Hemorrhagic dissection into an atheromatous plaque. d. Abnormal constriction of a coronary artery. 3. Progression of atherosclerosis as a result of plaque "healing." It may not be possible to identify the appropriate mechanism responsible for unstable angina in every case but the clinician must attempt to do so since the selection of appropriate therapy for the individual patient depends on the mechanisms responsible for the symptoms.

Early postinfarction angina: therapeutic strategies

In patients with recurrent chest pain in the immediate postinfarction state, one must determine whether the recurrent chest discomfort is related to myocardial ischemia or not. If recurrent ischemia is present then it may be due to either (1) transient increase of myocardial oxygen demand over a fixed coronary reserve, (2) transient decrease of myocardial oxygen supply, or (3) a combination of both. Coronary angiography reveals that most patients have double or triple vessel disease. The presence of postinfarction angina portends a poor prognosis. Reinfarction rate has been reported as high as 28% during initial hospitalization and mortality has been as high as 57% at six months follow-up. Intravenous nitroglycerin seems to be an important foundation therapy for the management of postinfarction angina. The use of beta blockers has reduced mortality by 24% compared to placebo in this patient subgroup. Calcium antagonists have proven efficacious in patients with non-Q-wave myocardial infarction and postinfarction angina. Thrombolytic therapy, chronic anticoagulation and antiplatelet therapy are not proven efficacious at this time. Coronary angioplasty is usually successful initially but is associated with an early myocardial infarction rate varying from 1.4 to 13%. Mortality rate is usually low as is late myocardial infarction rate. Recurrent angina occurs commonly in these patients. Surgical therapy in the early infarction state should be offered to those patients who have a poor response to maximal medical therapy whose coronary artery obstructions are not amenable to PTCA. At the time of coronary angiography if partially occlusive thrombus is identified, intravenous heparin and aspirin should be given to prevent more thrombus formation and total occlusion.

Balloon valvuloplasty 1988: a review

Catheter balloon valvuloplasty is a procedure which has been applied in stenotic lesions of all four cardiac valves in the last several years. This review discusses available data regarding the mechanism of effect, risks, and clinical utility of balloon valvuloplasty as it is applied to stenotic lesions of the pulmonic, mitral and aortic valves.

Silent myocardial ischemia: prognostic significance and therapeutic implications

Evidence is now accumulating which strongly suggests that prognosis of patients with painless myocardial ischemia determined either by ambulatory ECG monitoring or exercise testing may be no different than the prognosis of patients who have overt clinical manifestations of myocardial ischemia associated with transient ischemic ECG changes. In my view the goal of therapy for patients with clinical manifestations of coronary artery disease should be the elimination of myocardial ischemia. Medical therapy, coronary angioplasty, or coronary artery surgery should be rendered and then followed by objective documentation of therapeutic efficacy.