The long term prognosis in patients following thrombolysis for acute myocardial infarction: a view from a community hospital.

Thrombolysis in patients with acute myocardial infarction has been established to improve hospital survival. Less information is available about the long term evolution of unselected patients seen in community hospitals. Consequently, consecutive patients treated with thrombolysis for acute myocardial infarction and surviving until hospital discharge (n = 129) were followed for an average of 22 months. Mortality, recurrent ischemic events, coronary angiography and re-vascularizations were recorded for all patients. Two-year total and cardiovascular survival rates of 95 and 98% respectively were obtained with a conservative approach to early re-vascularization (n = 17, 13%). A history of prior myocardial infarction and early recurrent myocardial ischemia were significant predictors of increased cardiac events, while thallium stress testing provided no incremental value. Angiography and re-vascularizations were more frequently performed in younger patients (under 65 years old), anterior vs. inferior infarction and those with early residual ischemia. Women received less aggressive investigation and therapy then men and this may represent a gender bias, unmeasured residual confounding or the play of chance in a small sample size. Further studies are needed to confirm or refute these findings.

Risk stratification in patients with non Q wave myocardial infarction: a role for thallium exercise testing.

The ability of maximal exercise thallium testing to stratify patients after non Q wave myocardial infarction was prospectively examined in 20 patients. Patients were enrolled in the study if there was no evidence of residual ischemia nor congestive heart failure during initial hospitalization. The thallium exercise test showed four patients to be at high risk, three of whom had successful revascularization. The remaining 16 patients were considered to be at low risk. There were no re-admissions for unstable angina, no myocardial infarctions and no deaths in the follow-up period (average 15 months). Thus patients with no evidence of early ischemia, no signs of left ventricular failure and a negative maximum thallium exercise test are at low risk following non Q wave myocardial infarction.

Usefulness of the severity and extent of reversible perfusion defects during thallium-dipyridamole imaging for cardiac risk assessment before noncardiac surgery.

Thallium-dipyridamole imaging is a very sensitive test for predicting cardiac events after noncardiac surgery, but it lacks specificity. To improve specificity, a semiquantitative scoring system was developed that combined dipyridamole-induced reversible left ventricular dilatation with scintigraphic indexes for severity and extent of reversible perfusion defects. Using this scoring system, patients were classified into low, intermediate and high risk subgroups. Thallium-dipyridamole imaging was performed in 66 patients before major general and vascular surgery. Thirty-nine patients classified as low risk (30 with normal scans and 9 with fixed defects) underwent surgery uneventfully. Surgery was cancelled in 6 patients with extensive thallium redistribution and coronary angiography was performed because of severe coronary artery disease in 5 and idiopathic dilated cardiomyopathy in 1. In the remaining 21 patients with thallium redistribution, a positive statistical correlation (p = 0.001) between scintigraphic indexes of severity and extent, and cardiac events was noted. Using cutoff values for the scintigraphic indexes, patients with reversible defects could be classified into intermediate and high risk subgroups. Only 1 of 11 patients at intermediate risk developed a complication, whereas 8 of 10 patients at high risk had a postoperative event (7 deaths and 1 myocardial infarction). Thus, using scintigraphic indexes for severity and extent, patients with reversible defects can be stratified into an intermediate risk subgroup that can safely undergo surgery and a high risk subgroup that requires coronary angiography.