AORTIC COUNTERPULSATION MAY IMPROVE LATE PATENCY OF THE OCCLUDED CORONARY-ARTERY IN PATIENTS WITH EARLY FAILURE OF THROMBOLYTIC THERAPY

Objectives. Using a prospective, randomized design, we tested our hypo thesis that the augmentation of diastolic pressure by intraaortic ball oon counterpulsation (IABP) would improve the late patency of the occl uded coronary artery in patients with early failure of thrombolytic th erapy. Background. Rescue angioplasty is often performed in patients i n whom thrombolysis has failed, although 30% to 60% of the infarct-rel ated arteries that are closed early after thrombolytic therapy will op en later with conservative therapy. Methods. The study included 45 pat ients in whom thrombolysis had failed, despite treatment with intraven ous tissue type plasminogen activator (alteplase 0.75 mg/kg body weigh t) delivered over 60 min within 12 h of the onset of symptoms. All pat ients underwent coronary angiography 60 min after initiation of thromb olytic therapy (baseline), and Thrombolysis in Myocardial Infarction ( TIMI) grade 0, 1 or 2 flow was defined as failed thrombolysis. The pat ients were randomized to groups receiving IABP for 48 h (n = 23) or co nservative therapy (n = 22, control subjects) at the end of cardiac ca theterization. The late patency of the infarct-related artery, the pri mary end point of the study, was evaluated 3 weeks after myocardial in farction, Stenosis of the infarct-related artery was measured using a computer-assisted quantitative angiographic system in blinded manner. Data are expressed as mean value +/- SEM. Results. There was no differ ence with regard to the baseline value for TIMI flow grade between the groups. However, 3 weeks after myocardial infarction, the patients tr eated with IABP had a significantly higher frequency of TIMI flow grad e 3, lower residual percent stenosis and larger minimal lumen diameter of the infarct-related artery than did the control subjects (74% vs. 32%, p < 0.05; 42 +/- 5% vs. 68 +/- 6%, p < 0.01; and 1.6 +/- 0.1 vs, 0.9 +/- 0.2 mm, p < 0.01, respectively). Conclusions. These findings s uggest that in patients with early failure of thrombolytic therapy, IA BP may improve late patency of the occluded coronary artery, probably due to augmented perfusion pressure.