Preliminary Experience using Diastolic Right Ventricular Pressure Gradient Monitoring in Cardiac Surgery

Abstract Objectives Right ventricular (RV) dysfunction in cardiac surgery is associated with increased mortality, morbidity and difficult separation from cardiopulmonary bypass (DSB). The primary objective of this study was to describe the prevalence and characteristics of patients with abnormal RV diastolic pressure gradient (PG). Our secondary objective was to explore the association between abnormal diastolic PG and DSB, post-operative complications, high central venous pressure (CVP) and high RV end-diastolic pressure (RVEDP). Design Retrospective and prospective validation study. Setting Tertiary care cardiac institute. Participants Cardiac surgical patients (n=259) with 115 additional patients for external validation. Intervention RV pressure waveform were obtained using a pulmonary artery catheter with a pacing port opened at 19 cm distal to the tip of the catheter. Abnormal RV diastolic PG was defined as >4 mmHg. Both elevated RVEDP and high CVP were defined as >16 mmHg. Measurements and Main Results From the retrospective and validation cohort, 42.5% and 48% of the patients had abnormal RV diastolic PG before cardiac surgery. It was associated with higher EuroSCORE II (OR 2.29 [1.10-4.80] vs. 1.62 [1.10-3.04], p=0.041), abnormal hepatic venous flow (45% vs. 29%, p=0.038), higher body mass index (28.9 [25.5-32.5] vs. 27.0 [24.9-30.5], p=0.022), pulmonary hypertension (48% vs. 37%, p=0.005) and more frequent DSB (32% vs. 19%, p=0.023). However RV diastolic PG was not an independent predictor of DSB, while RVEDP (OR 1.67 [1.09-2.55], p=0.018) was independently associated with DSB. RV pressure monitoring indices were superior to CVP in predicting DSB. Conclusion Abnormal RV diastolic PG is common before cardiac surgery and associated with a higher proportion of known pre-operative risk factors. However, abnormal RV diastolic PG gradient is not an independent predictor of DSB in contrast to RVEDP.