Effect of preinfarction angina pectoris on microcirculation in patients with reperfused acute myocardial infarction

Abstract

Preinfarction angina pectoris has been suggested in some studies to have a beneficial effect on left ventricular function after acute myocardial infarction (AMI).The precise mechanisms of this protection have not been fully elucidated.The effect of preinfarction angina on myocardial tissue perfusion also needs to be clarified. In this study, we investigated the influence of preinfarction angina on microvasculatory damage by using ST-segment resolution and pressure-derived collateral flow index (CFIp) as a marker of microcirculatory perfusion.

Methods — We studied 41 patients with a first AMI in whom thrombolysis in myocardial infarction (TIMI) grade 3 flow in the infarct-related artery was established by thrombolytic therapy.The percent resolution of ST-segment deviation (DS ST) after thrombolysis was determined. All of the patients had TIMI grade 3 flow in IRA at the coronary angiography, which was done a mean of 4 days after AMI. Intracoronary pressure measurements and stent implantation to the IRA were performed. After angiography, CFIp was calculated as the ratio of simultaneously measured coronary wedge pressure – central venous pressure (Pv) to mean aortic pressure – Pv.

Results — Patients with preinfarction angina pectoris had greater percent DS ST than those without PA (67 ± 18% vs. 44 ± 24%, p = 0.03).The mean of the coronary wedge pressure (16.4 ± 7.4 compared with 23.2 ± 9.4, P < 0.03) and the pressure-derived collateral flow index (0.15 ± 0.10 compared with 0.22 ± 0.08, P < 0.03) were significantly lower in patients with preinfarction angina compared to those without.

Conclusion — Preinfarction angina is associated with a greater degree of ST-segment resolution and lower CFI-p in patients with TIMI-3 reflow after thrombolysis.These findings suggest that a protective effect of preinfarction angina against reperfusion injury may result in greater ST resolution and lower CFIp after AMI.

Key Words:

• preinfaction angina
• preconditioning
• pressure-derived collateral flow index
• ST-segment resolution