Intravascular physiologic evaluation of the left anterior small thoracotomy operation: a novel approach to left anterior descending artery revascularization.

Background: Efficacy and long-term patency rate of the left internal mammary artery (LIMA) conduits for revascularization of the left anterior descending coronary artery (LAD) has been demonstrated, with improved results as compared to the saphenous vein graft operation. Novel approaches to LAD revascularization including the use of the left anterior small thoracotomy (LAST) operation with persistence of the intercostal arteries compared to the traditional LIMA operation have not been reported. This study evaluated flow characteristics of LAST operation.

Methods: Phasic blood flow velocity in the proximal and distal arterial conduit segments was measured in 30 patients by intravascular Doppler flow wire after surgical revascularization of the LAD: 15 patients were revascularized by conventional operation using the LIMA (Group A), and 15 patients were submitted to the LAST operation (Group B). All patients underwent coronary angiography and ventriculography at 116 +/- 111 days after operation. Only angiographically normal grafts with normal left ventricular wall motion and coronary arteries free from significant distal stenosis were included for coronary flow velocity and reserve measurements.

Results: The diastolic/systolic velocity ratio in the proximal portion of the internal mammary artery was similar in the two groups (Group A 0.8 +/- 0.2 vs Group B 0.7 +/- 0.3, p = NS). Distal diastolic/systolic velocity ratio in Group A (1.7 +/- 0.1) was higher than Group B (0.9 +/- 0.3, p < 0.001). There were no differences in basal average peak velocity or coronary flow reserve between the proximal and distal segments for either groups.

Conclusions: Although proximal phasic coronary flow patterns between the two groups were similar, distal diastolic/systolic velocity ratio was higher in the LIMA than in the LAST. This difference may be related to the persistence of the intercostal artery in the LAST operation. These data confirm the continued patency and similar functional flow patterns compared to the conventional LIMA operation, supporting further investigation and application of this novel approach to LAD revascularization.