RESUMO
OBJECTIVE: RMBF measurement is a major concern in various clinical and experimental settings, but no validated device for RMBF is currently available. METHODS: An LVP-triggered laser Doppler to measure RMBF was validated by simultaneous fluorescent MS RMBF in a porcine LAD flow reduction model (n = 10 pigs). The laser probe was positioned on the left ventricle's anterior wall. LAD blood flow reduction was achieved by a shaft-driven occluder positioned proximal to the transit-time flow meter measuring coronary blood flow. RMBF was measured at baseline; after the reduction of LAD blood flow to 70% and 30% of baseline; at 20 and 120 minutes of reperfusion; and, finally, 15 minutes after LAD occlusion. RESULTS: Laser Doppler RMBF (LDU) correlated strongly with MS RMBF under all tested conditions: baseline (epicardial 194.7 ± 41.9, endocardial 130.2 ± 29.2); 70% baseline-flow (epicardial 160.4 ± 27.7, endocardial 112.1 ± 15.1); 30% baseline-flow (epicardial 44.3 ± 5.5, endocardial 32.9 ± 9); 20 minutes reperfusion (epicardial 175.8 ± 33.6, endocardial 126.5 ± 30); 120 minutes reperfusion (epicardial 146.3 ± 31.1, endocardial 107.1 ± 29.7); and complete LAD occlusion (epicardial 10.5 ± 5.8 endocardial 1.4 ± 0.3) (r = 0.986-0.962, p < 0.001). CONCLUSIONS: This new blood pressure waveform-triggered laser Doppler probe is able to measure RMBF at different depths online in the beating heart.