Circulating platelet aggregate size in ischemic heart disease

Circulating aggregated platelets, number of platelets per aggregate, and platelet size during acute myocardial infarction

Circulating aggregated platelets (total, reversibly and irreversibly aggregated), the number of platelets per aggregate and "big" platelets were measured by a modification of the Wu and Hoak method in 42 patients on the first, second and fifth day of acute myocardial infarction (AMI). Among them, 30 had an uncomplicated course and 12 patients had complications that occurred between the 5th and 10th day of hospitalization (7 patients had reinfarction and 5 died). In all patients the measured parameters were elevated compared with those of control subjects. There was a significant increase, especially after the first observation day, in the values of total aggregated platelets (37 +/- 11% vs 26 +/- 12%, p < 0.001), reversibly aggregated platelets (27 +/- 9% vs 17 +/- 8%, p < 0.001) and the average platelets per aggregate (8.6 +/- 0.3 vs. 2.3 +/- 0.4) in patients with versus without complications. In considering the role of platelets in the development of AMI, these findings may add information to the role of platelets in determining the course of AMI.

Unstable angina

Unstable angina can manifest as an array of symptom complexes. In some patients, medical therapy will stabilize the episodes of angina, and only predismissal exercise testing or angiography (or both) will be necessary. At the other end of the spectrum are patients with rest angina or multiple episodes of silent ischemia who are refractory to medical therapy and experience undetected microinfarction. Most of these patients require immediate catheterization and subsequent intervention with intra-aortic balloon pulsation, percutaneous transluminal coronary angioplasty, or coronary artery bypass grafting. An entire spectrum of manifestations exists between these two extremes. One challenge during the 1990s will be better stratification of patients with unstable angina so that safe, efficient, cost-effective treatment strategies can be appropriately applied to all patients.