Background: The mortality and morbidity of aortic valve replacement (AVR) after prior coronary artery bypass surgery (CABG) with patent left internal thoracic artery (LITA) is significant. The risk of LITA injury and inadequate myocardial preservation during the cross-clamp period may cause myocardial pump failure.
Methods: A total of 43 patients with a patent LITA graft underwent AVR. The patients were divided into the two groups. Group 1 included 19 patients who underwent AVR with deep hypothermia (20 degrees C) without LITA clamping. Group 2 included 24 patients in whom LITA flow was controlled through supraclavicular occlusion and AVR performed with moderate hypothermia (28 degrees C).
Results: Average cardiopulmonary bypass time (CPB) time was 118.79 +/- 20.36 minutes in group 1 and 102.67 +/- 9.66 minutes in group 2 (p = 0.006). Average cross-clamp time was 53.79 +/- 7.26 minutes in group 1 and 49.63 +/- 6.7 minutes in group 2 (p = 0.022). Inotropic support was required in 12 patients in group 1 and 4 patients in group 2 (p = 0.002). Average intensive care unit stay was 4.68 +/- 2.24 days in group 1 and 2.29 +/- 0.46 days in group 2 (p < 0.001). Average hospital stay was 11.84 +/- 2.91 days in group 1 and 8.04 +/- 2.38 days in group 2 (p < 0.001). Mortality due to myocardial failure developed in 4 patients in group 1 but in none of the patients in group 2 (p = 0.02).
Conclusions: Proximal control of LITA flow by extrathoracic supraclavicular occlusion reduces the incidence of myocardial failure due to nonhomogenous cardioplegia delivery to the anterior wall of the heart, resulting in improved myocardial protection and the elimination of the need for deep hypothermia.