Baseline intra-operative left ventricular diastolic function predicts postoperative length of stay in patients with normal systolic function undergoing isolated coronary artery bypass surgery

Importance: Abnormal left ventricular (LV) diastolic function, with or without a diagnosis of heart failure, is a common finding that can be easily diagnosed by intra-operative transesophageal echocardiography (TEE). The association of diastolic function with duration of hospital stay after coronary artery bypass (CAB) is unknown. Objective: To determine if abnormal LV diastolic function (diastolic dysfunction) is associated with length of hospital stay after coronary artery bypass surgery (CAB). Design: Prospective observational study Setting: A single tertiary academic medical center Participants: Patients with normal systolic function undergoing isolated CAB from September 2017 through June 2018. Exposures: LV function during diastole, as assessed by intra-operative TEE prior to coronary revascularization. Main Outcomes and Measures: The primary outcome was duration of postoperative hospital stay. Secondary intermediate outcomes included common postoperative cardiac, respiratory, and renal complications. Results: The study included 176 participants (mean age 65.2 +/- 9.2 years, 73% male); 106 (60.2%) had LV diastolic dysfunction. Median time to hospital discharge was significantly longer for subjects with diastolic dysfunction (9.1/IQR 6.6-13.5 days) than those with normal LV diastolic function (6.5/IAR 5.3-9.7days) (P< 0.001). The probability of hospital discharge was 34% lower (HR 0.66 / 95% CI 0.47-0.93) for subjects with diastole dysfunction, independent of potential confounders, including a baseline diagnosis of heart failure. There was a dose-response relation between severity of diastolic dysfunction and probability of discharge. LV diastolic dysfunction was also associated with postoperative cardio-respiratory complications; however, these complications did not fully account for the relation between LV diastolic dysfunction and prolonged length of hospital stay. Conclusions and Relevance: In patients with normal systolic function undergoing CAB, diastolic dysfunction is associated with prolonged duration of postoperative hospital stay. This association cannot be explained by baseline comorbidities or common post-operative complications.