Myocardial ischemia : As a risk indicator after an episode of unstable angina or non-Q-wave myocardial infarction

Abstract: The diagnostic and prognostic value of different noninvasive tests were evaluated in men below 70 years of age admitted to the coronary care unit (CCU) with unstable coronary artery disease (CAD) i.e unstableangina or non-Q-wave myocardial infarction (Ml). A symptom limited exercise test (ET) was performed before discharge in 740 patients. In subgroups 24 hour ST-recordings were performed in the CCU (n=75),before discharge (n=198) and ambulatory after one month (n=109). A second ET combined with SPECT Tl201 myocardial perfusion imaging was done after one month in 197 patients. Myocardial ischemia was defined as ST-depression > 0.1 m V or according to a model developed for interpretation of SPECTT1201 scintieraphy. All patients were followed one year.Patients with myocardial ischemia at the predischargc ET (51 %) had a significantly higher rate of death or MI (18 %) compared to those without (9 %) regardless of simultaneous pain or not. STrccordingin the acute phase or before discharge showed less often myocardial ischemia (23-18 %) than ambulatory during ordinary daily life (33 %). In the same group of patients myocardial ischemia was more often elicited by a predischarge ET (52%). The majority of patients with ST-depression at ST-recordings also showed myocardial ischemia at the predischarge ET. Myocardial ischemia at the ST-rccording beforedischarge identified a small group (18 %) of patients with a more severe prognosis- 23% rvn or death after 3 months compared to 7 % in the patients without this observation. In a logistic regression analysis ST-depression at the predischarge ST-recording was the only significant predictor of MI or death during the first three months while myocardial ischemia at the predischarge ET became the only significant indicator of long term outcome. In a comparison between the predischarge and the one month ET 83 % of patients showed the same response regarding occurrence of ST -depression. The rate of MI or death during the first month were more common in patients with (8.3 %) than without (3.7 %) myocardial ischemia at the predischarge ET and so was the occurrence of future symptoms of severe angina. Regarding the following 11 months, myocardial ischemia at the predischarge or the one month ET had the same prognostic importance for MI, death or severe angina. SPECT Tl 201 imaging at ET improved the separation between high and low risk patients. If both SPECT Tl 201 imaging and the ECG response showed signs of ischemia (37 %) the risk of future cardiac events was markedly elevated- 17 % MI or death compared to 7 % in patients without this finding. Thus, risk stratification of men after an episode of unstable coronary artery disease can be performed already before discharge. Patients with continuing myocardial ischemia despite treatment should be considered for rcvascularisation whether or not the ischemia is associated with pain.