PO-02-202 CORONARY SINUS PRESSURE FOLLOWING RETROGRADE CARDIOPLEGIA PREDICTS POSTOPERATIVE ATRIAL FIBRILLATION

Abstract

Coronary sinus cannulation and occlusion are routinely performed during cardiac surgery for administration of retrograde cardioplegia. Under these circumstances, coronary sinus occlusion pressure closely parallels left ventricular end-diastolic pressure, and thus serves as a surrogate for left atrial pressure. Left ventricular diastolic dysfunction has been identified as an important predictor of post-operative atrial fibrillation (POAF). In the setting of impaired left ventricular compliance, left atrial pressure is highly sensitive to very small volume shifts, thereby stretching the left atrium and increasing pulmonary veins arrhythmogenic activity. We hypothesized that elevation of coronary sinus occlusion pressure during cardiac surgery is indicative of increased left atrial pressure and thus may predict the occurrence of POAF. Consecutive patients (n=91, age 65 ± 11yrs) underwent cardiac surgery with retrograde cardioplegia. Patients with a history of atrial fibrillation were excluded. Baseline mean coronary sinus occlusion pressure was obtained following cannulation of the coronary sinus for administration of retrograde cardioplegia before initiation of bypass. The mean coronary sinus occlusion pressure was measured again during bypass as well as immediately after removal of the aortic cross clamp. Clinical outcomes and post-operative complications were collected until hospital discharge. Baseline clinical and procedural characteristics were compared among patients who developed POAF and those who did not. Eleven of the 91 patients (12%) developed POAF. In patients who developed POAF, post-bypass cardiac index was lower (2.4±0.3 vs 2.9±1.1 L/min/m2, p =0.004) and post-bypass coronary sinus occlusion pressure was higher compared to those who did not (16.5±9.5 vs 9.0±6.0 mm Hg, p = 0.036). Post-bypass coronary sinus occlusion pressure was independently predictive of POAF after adjusting for post-bypass cardiac index [OR 1.2 (95% CI 1.1-1.3), p=0.003]. Post-bypass coronary sinus occlusion pressure is significantly higher in patients who develop POAF, reflecting the development of post-bypass impaired relaxation and increased left atrial pressure. Given the ubiquitous use of coronary sinus occlusion during bypass procedures and the ease of measurement of post-bypass coronary sinus occlusion pressure, this may be a valuable and inexpensive tool for POAF risk stratification.