Enhancement of coronary reactive hyperemia in patients with ischemic myocardial tolerance during angioplasty

Abstract

The purpose of this study was to elucidate the effect of repeated brief coronary occlusions on reactive hyperemia during percutaneous transluminal coronary angioplasty (PTCA) in patients with or without ischemic tolerance. Seventeen patients undergoing PTCA for chronic stable angina were studied. Patients with well developed collateral vessels were excluded. After successful predilatation, coronary flow velocity was recorded with the use of a Doppler flow guide wire, and reactive hyperemia was assessed immediately after each of two 2-min coronary occlusions followed by 2 mins of reperfusion. The intracoronary electrocardiogram (icECG) was recorded via the flow guide wire placed in the center of the ischemic zone. Patients were divided into two groups: those who showed a reduction of ST elevation in the icECG recorded at the time of the second coronary occlusion (group I), and those who showed no difference in ST elevation between the two occlusions (group II). There were no significant differences in blood pressure, heart rate, or baseline coronary flow velocity between the two groups before the first occlusion, but the ST elevation at the time of the first coronary occlusion was greater in group I than in group II (8.9 +/- 6.2 versus 1.1 +/- 2.0 mm, P < 0.01). Reactive hyperemia was significantly greater after the second coronary occlusion than after the first in group I (22.1 +/- 15.8 versus 30.4 +/- 21.0 cm/s, P < 0.05), but it did not change in group II (25.6 +/- 13.0 versus 23.5 +/- 11.2 cm/s NS). Reactive hyperemia was enhanced in patients with ischemic tolerance who showed a reduction in St elevation in the icECG. These results suggest that observed reactive hyperemia does not necessarily reflect the severity of ischemia.

The Intracoronary Electrocardiogram in Percutaneous Coronary Intervention

“…69 The IC-ECG was used to prove regional ischemia during balloon angioplasty of septal branches during treatment of hypertrophic obstructive cardiomyopathy. 70 Other miscellaneous uses of the IC-ECG described included atrial pacing stress testing postangioplasty, 71 assessing and adjusting holter lead sensitivity to capture ischemia using the IC-ECG as "gold standard", 72 investigating diastolic pressure rise in coronary ischemia, 73 studying the relationship between hyperemia and ischemic tolerance, 74 and clarifying the mechanisms of abnormal Q waves on S-ECG in hypertrophic cardiomyopathy. 75 The Intracoronary Electrocardiogram in Clinical Practice.…”

“…Other miscellaneous uses of the IC‐ECG described included atrial pacing stress testing postangioplasty, 71 assessing and adjusting holter lead sensitivity to capture ischemia using the IC‐ECG as “gold standard”, 72 investigating diastolic pressure rise in coronary ischemia, 73 studying the relationship between hyperemia and ischemic tolerance, 74 and clarifying the mechanisms of abnormal Q waves on S‐ECG in hypertrophic cardiomyopathy 75 …”