IMPROVEMENT IN INDUCIBLE ISCHEMIA DURING DOBUTAMINE STRESS ECHOCARDIOGRAPHY AFTER TRANSMYOCARDIAL LASER REVASCULARIZATION IN PATIENTS WITH REFRACTORY ANGINA-PECTORIS

Objectives. The purpose of this ongoing study is to determine whether transmyocardial laser revascularization (TMLR) can lessen inducible is chemia and improve contractile reserve in patients with refractory ang ina pectoris. Background. TMLR is an emerging surgical technique for t he treatment of myocardial ischemia and angina pectoris not amenable t o conventional percutaneous or surgical revascularization, Objective d ata documentating a reduction in ischemia during noninvasive stress te sting after TMLR are rare. Methods. Fifteen patients with severe coron ary artery disease unsuitable for treatment with standard revasculariz ation techniques were studied,vith dobutamine stress echocardiography (DSE) before TMLR. Of the 12 patients who underwent TMLR, DSE was repe ated at 3 months postoperatively in 11 patients and at 6 months in 9 p atients. Stress echocardiograms were analyzed for inducible ischemia, with calculation of the wall motion score index (WMSI). Heart rate and dobutamine dose achieved at peak stress were also assessed as indexes of stress tolerance. Results. Compared with that before TMLR, wall mo tion at rest for all myocardial segments did not change significantly after TMLR, although there was a mild improvement in the WMSI of the l ased myocardial regions ([mean +/- SD] 1.64 +/- 0.34 after vs. 1.78 +/ - 0.34 before TMLR, p < 0.05). Overall WMSI at peak stress improved ma rkedly after TMLR (1.70 +/- 0.30 after vs. 2.06 +/- 0.31 before TMLR, p < 0.002), with the improvement in WMSI limited to the lased segments only (1.47 +/- 0.31 after vs. 2.15 +/- 0.34 before TMLR, p < 0.0004), The improvement in WMSI with stress resulted primarily from a decreas e in the percentage of ischemic segments (47% before vs. 23% after TML R, p < 0.0008), with no change in the percentage of infarcted segments (23% before vs. 26% after TMLR). Heart rate (83 +/- 5 beats/min befor e vs. 102 +/- 21 beats/min after TMLR, p = 0.01) and dobutamine infusi on rate (26 +/- 9 mu g/kg body weight per min before vs, 34 +/- 9 mu g /kg per min after TMLR) achieved at peak stress also increased postope ratively, consistent with improved stress tolerance. The reduction in ischemic wall motion abnormalities and improved stress tolerance persi sted at 6 months, without evidence of further improvement or deteriora tion of function over time. Conclusions. TMLR performed in patients wi th refractory angina pectoris reduces ischemic wall motion abnormaliti es and improves stress-induced tolerance during dobutamine echocardiog raphy. These beneficial effects persist up to 6 months postoperatively . (C) 1997 by the American College of Cardiology.