Abstract
Background
Severe mitral regurgitation (MR) induces significant changes not only in the left, but also in the right ventricular (RV) morphology and function. Early treatment of MR is recommended, however, surgical procedure disrupts the native RV contractile pattern and predisposes the at-risk ventricle to develop postoperative RV failure (RVF) which is associated with poor outcomes.
Purpose
Accordingly, the PREPARE-MVR study (PRediction of Early PostoperAtive Right vEntricular failure in Mitral Valve Replacement/Repair patients) aims to explore the alterations of RV contraction pattern in patients undergoing MVR and to investigate the association of preoperative echocardiographic findings with early postoperative RVF.
Methods
We prospectively enrolled 70 patients (62±12 years, 67% males) undergoing open heart MVR. Thirty age and gender matched healthy volunteers served as control group. Transthoracic 3D echocardiography was performed preoperatively and at intensive care unit discharge. Furthermore, focused 2D echocardiogram was also obtained during the ICU stay. Forty-three patients also completed 6 months follow-up. 3D model of the RV was reconstructed and end-diastolic volume index (EDVi) along with RV ejection fraction (RVEF) were calculated. For in-depth analysis of RV mechanics, we decomposed the motion of the RV to compute longitudinal (LEF) and radial ejection fraction (REF). Right heart catheterization was performed to monitor RV stroke work index (RVSWi).
Results
RV morphology as assessed by EDVi was unaffected by surgery (preoperative vs postoperative; 73±17 vs 71±16 mL/m2, p=NS). RVEF was slightly decreased after MVR (52±6 vs 48±7%, p<0.05), whereas RV contraction pattern has changed notably. Before MVR, the longitudinal shortening was the main contributor to global systolic function (LEF/RVEF vs REF/RVEF; 0.53±0.10 vs 0.43±0.12; p<0.001), whereas in controls the longitudinal and radial shortening contributed equally to RVEF (0.47±0.07 vs 0.43±0.09; p=NS). Postoperatively, the radial motion became dominant (0.35±0.08 vs 0.47±0.09; p<0.001). However, this shift was only temporary as 6 months later the contraction pattern became similar to controls showing equal contribution of the two components (0.44±0.10 vs 0.42±0.11; p=NS). Postoperative RVF (defined as RVSWi <300 mmHg*mL/m2 or ICU TAPSE <10 mm) was detected in 14 [20%] patients. Preoperative LEF was associated with postoperative RVSWi (r=−0.61, p<0.001) and it was an independent predictor of postoperative RVF (OR=1.16 [1.03–1.35], p<0.05).
Conclusion
Severe MR induces a significant shift in the RV mechanical pattern which may influence the development of postoperative RV dysfunction and failure after MVR. Advanced indices of RV mechanics are associated with invasively measured parameters of RV contractility and may predict postoperative RVF.
Echocardiographic Features of Refractory Right Ventricular Failure Treated with Atrial Septostomy-Following Mitral Valve Replacement
