Coronary reserve, extent of coronary disease, recurrent angina and ECG changes during pain in the in-hospital prognosis of acute coronary syndromes.

The prognostic value of recurrent angina, severity of coronary disease, ECG changes during pain and coronary reserve (ischaemic threshold measured by atrial pacing: heart rate with ST segment shift = 1 mm), was evaluated in 383 consecutive patients with acute coronary syndromes. Univariate analysis showed a significant relationship between occurrence of complications (death, infarction or coronary surgery) and number of anginal episodes, extent of coronary disease, ischaemic threshold and ST depression with pain. A multivariate analysis indicated that the first three parameters were the main independent predictors. Coronary reserve was reduced (threshold < or = 150 beats.min-1) in 83% of patients who had a myocardial infarction (40), in 91% of those who died (11), in 87% of those who underwent coronary surgery (52) and in 47% of uncomplicated cases (301). Also, a low ischaemic threshold was associated with a larger number of anginal episodes than a high threshold (< or = 130 beats.min-1, 6.1 +/- 5.6 vs > 150 beats.min-1, 2.9 +/- 4.1, P < 0.0001), and in complicated patients with one-, two- or three-vessel disease ischaemic threshold (137.3 +/- 21.2, 133.3 +/- 18.9, and 135.1 +/- 21.2 beats.min-1, respectively) was lower than in the uncomplicated ones (153.4 +/- 20.1, P < 0.005; 148.2 +/- 19.1, P < 0.005; and 139.2 +/- 23.0 ns, beats.min-1). A threshold < 150 beats.min-1 and ECG changes during pain identified the subset with the highest risk for complications (59/137, 45%), whereas a threshold > 150 beats.min-1 and absence of pain or ECG changes during pain identified those with the lowest risk (5/109, 5%, P < 0.001). Thus, our findings document the prognostic significance of coronary reserve for in-hospital complications in patients with acute coronary syndromes and confirm the prognostic value of previously known risk markers. They also indicate that some of them may be significantly influenced by the status of coronary reserve.