Early postoperative changes in regional systolic and diastolic left ventricular function after transmyocardial laser revascularization - A comparisonof Holmium : YAG and CO2 lasers

OBJECTIVES The purpose of this study was to determine the short-term effect s of transmyocardial laser revascularization (TMR) on regional left ventric ular systolic and diastolic function, myocardial blood flow (MBF) and myoca rdial water content (MWC). BACKGROUND Clinical studies of TMR have noted, a significant incidence of c ardiac complications in the early postoperative period. However, the early post-treatment effects of laser therapy on the myocardium and their potenti al contribution to postoperative cardiac morbidity are unknown. METHODS Swine underwent holmium:yttrium-aluminum-garnet (holmium:YAG) (n = 12) or carbon dioxide (CO2) (n = 12) laser TMR. Regional systolic function for the lased and nonlased regions was quantitated using preload recruitabl e work area (PRWA) and regional diastolic function with the ventricular sti ffness constant alpha. RESULTS Preload recruitable work area was significantly decreased in the la sed regions both 1 (59.8 +/- 13.0% of baseline, p = 0.02) and 6 h (64.2 +/- 9.4% of baseline, p = 0.02) after holmium:YAG TMR. This decreased PRWA. wa s associated with a significant reduction in MBF to the lased regions (13.2 % reduction at 1 h, p = 0.02; 18.4% decrease at 6 h post-TMR, p = 0.01). Th ese changes were not seen after CO2 laser TMR A significant increase in MWC (1.4 +/- 0.3% increase with holmium:YAG, p = 0.004; 1 +/- 0.2% increase wi th CO2, p = 0.002) and alpha (217.4 +/- 44.2% of baseline 6 h post-holmium: YAG TMR, p = 0.05; 206 +/- 36.7% of baseline 6 h post-CO2 TMR, p = 0.03) wa s seen after TMR with both lasers. CONCLUSIONS In the early postoperative setting, impaired regional systolic function in association with regional ischemia is seen after TMR with a hol mium:YAG laser. Both holmium:YAG and CO2 lasers are associated with increas ed MWC and impaired diastolic relaxation in the lased regions. These change s may explain the significant incidence of early postoperative cardiac morb idity. The impact of these findings on anginal relief and long-term outcome are not known. (C) 2000 by the American College of Cardiology.