Quantitative analysis of myocardial perfusion changes with transmyocardiallaser revascularization

Transmyocardial laser revascularization (TLR) is a technique of creating le ft ventricular transmural channels in patients with refractory angina. We a imed to measure perfusion changes quantitatively using technetium-99m metho xyisobutyl isonitrile. perfusion scans were performed on 94 TLRs and in 94 control patients at rest and during exercise at assessment, and 3-, 6-, and 12-month follow-up. A serial set of scans allowed direct comparison of eac h patient over all visits. Bull's-eyes were divided into 5 anatomic regions and a 20-region model. Severity values were calculated for rest, stress, a nd each cardiac region using a threshold of 1 for analysis. Higher scores i ndicated greater severity of ischemia and lower perfusion. At 3-month follo w-up, the severity was significantly worse during TLR than in control patie nts both during stress (0.172 +/- 0.003 and 0.161 +/- 0.003, respectively, p = 0.007) and at rest (0.170 +/- 0.003 and 0.158 +/- 0.003, respectively, p = 0.002). At 6 months, severity during stress was 0.176 +/- 0.003 with TL R and 0.162 +/- 0.003 in controls (p = 0.001), with no significant differen ce at rest. At 12 months, there was no significant difference between TLR a nd control groups at stress and rest. Regional severity deteriorates during TLR compared with control patients anteriorly (p = 0.001, p = 0.0016, p = 0.005 at 3, 6, and 12 months), apically (p = 0.005, p = 0.0046, p = 0.032, respectively), and laterally (p <0.0001, p = 0.001, p = 0.002, respectively ). An apparent improvement is observed in the inferoseptal region at 6- and 12-month follow-up-an area not lasered. Thus, TLR appears to produce deter ioration in resting myocardial perfusion in lasered regions, and improvemen t in nonlasered regions, with no difference in exercise-induced myocardial ischemia compared with that in control patients. <(c)> 2001 by Excerpta Med ica, Inc.