ANTIISCHEMIC AND ANTIANGINAL EFFECTS OF THORACIC EPIDURAL-ANESTHESIA VERSUS THOSE OF CONVENTIONAL MEDICAL THERAPY IN THE TREATMENT OF SEVERE REFRACTORY UNSTABLE ANGINA-PECTORIS

Background Cardiac sympathetic blockade by thoracic epidural anesthesi a (TEA) dilates stenotic coronary arteries and has been used to contro l pain id patients with unstable angina. The aim of the present study was to evaluate the potential anti-ischemic effects of cardiac sympath etic blockade by TEA in severe, refractory, unstable angina. Methods a nd Results Forty patients with unstable angina refractory to standard anti-anginal therapy were randomized to receive either continuous epid ural infusion of bupivacaine (TEA, Th1 to Th5) or to standard anti-ang inal therapy including beta-blockers, calcium antagonists, aspirin, he parin, and nitroglycerin infusion (control group). The primary end poi nts were number of anginal attacks and severity of myocardial ischemia assessed by 48-hour ambulatory Holter monitoring. The incidence of my ocardial ischemia was lower in the TEA group (22% versus 61%; P < .05) . The number of ischemic episodes per patient was 1.0 +/- 0.6 in the T EA group and 3.6 +/- 0.9 in the control group (P < .05). The episode d uration per patient was 4.1 +/- 2.5 minutes and 19.7 +/- 6.2 minutes i n the TEA and the control groups, respectively (P < .05). The mean are a-under the-ST-time-curve was 6.8 +/- 4.3 and 32.2 +/- 14.3 (mm.min) i n the TEA and the control groups, respectively (P < .05). Fifteen angi nal attacks were recorded in the control group and one attack in the T EA group (0.83 +/- 0.21 versus 0.06 +/- 0.06/patient, respectively, P < .01). Conclusions The anti-ischemic and anti-anginal effects of cont inuous TEA are superior to those of conventional therapy in the treatm ent of refractory unstable angina.