Comparative study on the enhancement of ischemic tolerance by intracoronary pretreatment with three calcium antagonists in pig hearts

Abstract

The effect of intracoronary (IC) pretreatment with different calcium antagonists (diltiazem, nifedipine, verapamil) on the development of infarcts was investigated in two experimental series including 35 open-chest pigs. The left anterior descending coronary artery (LAD) was distally ligated for 75 minutes (series A) or for 45 minutes (series B) and was reperfused for 24 hours. Infarct size was determined as the ratio of infarcted myocardium (tetrazolium stain) to the risk region (dye technique). In series A, 20 pigs were pretreated immediately before occlusion with either IC diltiazem (n = 5, 4 mg/2 min), IC nifedipine (n = 5, 0.4 mg/2 min), IC verapamil (n = 5, 1 mg/2 min), or isotonic sodium chloride solution (n = 5). In series B, IC diltiazem (n = 5, 4 mg/2 min), IC verapamil (n = 5, 1 mg/2 min), or isotonic saline solution (n = 5) were administered 8 minutes prior to ischemia. The IC infusion of all calcium antagonists (series A) depressed left ventricular peak pressure, diastolic blood pressure, and dp/dt max and increased heart rate and coronary venous oxygen saturation. The development of infarcts was significantly delayed by IC diltiazem and IC verapamil. Mean infarct sizes (series A) amounted to 62% in the diltiazem group, 88% in the nifedipine group, 40% in the verapamil group, and 94% in the control group. In series B, where a time period of 8 minutes elapsed between pretreatment and induction of ischemia, mean infarct sizes after 45 minutes of ischemia and 24 hours of reperfusion amounted to 47% in the diltiazem group, 4% in the verapamil group, and 76% in control experiments.(ABSTRACT TRUNCATED AT 250 WORDS)

Intracoronary verapamil for reversal of no‐reflow during coronary angioplasty for acute myocardial infarction

“…We had experience with a dose of 1 mg verapamil given over 2 min in an earlier study on ischemia protection during PTCA [33]. The dose of 1 mg appears to be highly effective as shown in comparative studies of various calcium antagonists in animal experiments [37]. Recent studies on the hemodynamic effect of intracoronary verapamil support the selection of 1 mg as the most effective dosage to improve coronary flow and to reduce peripheral coronary resistance [38, 39].…”

The effects of prior calcium channel blocker therapy on creatine kinase-MB levels after percutaneous coronary interventions

“…Klein and colleagues (1989) have found that the development of infarcts were significantly delayed and the mean infarct sizes were smaller with intracoronary infusion of diltiazem, verapamil or nifedipine indicating that CCBs increase the ischemic tolerance significantly by their effects on calcium homeostasis in the setting of acute ischemia during baloon inflations at PCI.…”