Evaluation of the impact of transmyocardial laser (CO2) revascularisation on myocardial perfusion--6-months observations.

BACKGROUND: Transmyocardial laser revascularisation (TMLR) is a relatively new surgical approach to symptomatic coronary artery disease patients otherwise inoperable by classical revascularisation methods. Perfusion improvement after TMLR is considered as one possible mechanism causing alleviation of symptoms in a significant percentage of operated patiens. The goal of this work was to assess the history f myocardial perfusion during the first 6 month after sole TMLR operation. METHODS: TMLR was performed by using high-power (800 W) CO(2) laser. Tc-99m-Sestamibi single photon emission computed tomography (SPECT), both in rest and stress, was performed 4 times: before TMLR [SPECT-0], very early (mean: 3 weeks) after TMLR [SPECT-I], 3 months after TMLR [SPECT-II] and 6 months after TMLR [SPECT-III] in every patient. The group consisted of 25 patients, including 21 patients with previous myocardial infarctions. The patients subjected to the operation were those suffering from angina in spite of pharmacological therapy, with diffuse changes in the peripheral parts of coronary arteries, with left ventricle (LV) ejection fraction not lower than 0.30 and with at least one transient or small persistent defect in preoperative SPECT. Perfusion was assessed in 13 of 17 segments of the LV (after exclusion of 4 septal segments). Only a history of transient or small persistent perfusion defects ('viable' segments) detected in SPECT-0 is discussed. RESULTS: In comparison to SPECT-0: in SPECT-I perfusion did not change in 52% of segments, improved--in 31%, and deteriorated--in 17%: in SPECT-II perfusion did not change in 48% of segments, improved--in 34%, and deteriorated--in 18%; in SPECT-III perfusion did not change in 52%, improved--in 25%, and deteriorated--in 22% of segments. No significant difference in the number of segments with perfusion preservation, improvement or deterioration in comparison to SPECT-0 was found in SPECT-I,-II or III. In SPECT-II in comparison to SPECT-I, no changes in perfusion were found in 66% of segments, perfusion improved in 20% and deteriorated in 14%. In SPECT-III in comparison to SPECT-II, no changes in perfusion were found in 79% of segments, perfusion improved in 5% and deteriorated in 15%. CONCLUSIONS: Our evaluation of the history of segments with preoperatively transient or small persistent ('viable') defects indicates that during the first 6 months after TMLR: 1) perfusion is better than before the operation in about one third of the segments, and 20 in some of these segments there are dynamic perfusion changes (improvement or deterioration) from one to the next postoperative moment of observation.