Does chronic treatment with calcium entry blocking drugs reduce perioperative myocardial ischemia?

Abstract

To examine the role of chronic calcium entry blocking drug administration on perioperative myocardial ischemia and, specifically, the frequency of hemodynamically unrelated ischemia, the authors studied 444 patients undergoing coronary artery bypass operations. Before induction of anesthesia, 119 patients who chronically took calcium entry blocking drugs received nifedipine 20 mg or diltiazem 60 mg orally, 74 received calcium entry and beta adrenergic blocking drugs, 71 received beta blocking drugs only, and 180 received neither. New ischemia occurred in 208 (46.8%) patients; 55 at arrival to the operating room, 86 only after induction, and 67 separately during both periods. Two-thirds of all ischemia was not related to extremes of heart rate or blood pressure; this type was not less frequent in patients receiving calcium entry blocking drugs. Ischemia did occur less frequently in the two patient groups receiving beta adrenergic blocking drugs (34% vs. 53%), a result of less tachycardia both on arrival (3.4% vs. 15.4%) and during anesthesia, when peak heart rate exceeded 109 bpm in only one of 145 beta-blocked patients compared to 29 of 299 not receiving beta blocking drugs. While ischemia appeared during anesthesia in 34.5% of all patients, its incidence was doubled (63%) when heart rate was greater than or equal to 110 bpm. At lower heart rates, the incidence of ischemia did not differ among groups. With respect to all types of ischemia, patients receiving calcium entry blocking drugs only were indistinguishable from those receiving no antianginal therapy.(ABSTRACT TRUNCATED AT 250 WORDS)