Experimental Biology 2010: Cardiac MRI Analysis Of Right Ventricular Function In Valvular Heart Disease

Purpose of Study: In valvular heart disease, elevated left atrial and pulmonary artery pressures(PAP) can lead to right ventricular strain and right ventricular failure. Elevated left ventricular end-diastolic pressure (LVEDP) and PAP are risk factors that influence survival after valve surgery. Accurate quantification of right ventricular function can be assessed by cardiac MRI (cMRI). The relationship between cMRI analysis of RVEF and cardiac hemodynamics with regard to outcome remain undefined.

Methods Used: Between January 2004 and February 2008, 49 consecutive patients undergoing valvular heart surgery (40 AVR, 6 MVR, 3 TVR) had preoperative cardiac catheterization and cMRI. 93% were males, average age=65 yrs (39-83), and a majority of patients had diabetes, and hypertension. Cardiac MRI was performed by one technician and all studies analyzed by one cardiologist. Preoperative PAP and LVEDP were compared to RV cMRI analysis to determine 1) relation of RVEF to severity of pressure overload on the right ventricle and 2)prognostic value of RVEF in patients undergoing valvular heart surgery.

Summary of Results: By cardiac catheterization, LVEDP was 23.3±13 mmHg and PAP was 41±14 mmHg, signifying significant elevated left and right sided pressures. By cMRI, LVEF was 57±16% and RVEF was 47.8±10%, both in near normal range; however, RVEDV was 103.5±80 mm, which represents mild RV volume overload. For the group, risk adjusted estimated mortality was 6±5%(1.2-55%); yet actual mortality was only 4% (n=2).

Conclusions: In patients presenting for valvular heart surgery, accurate LV and RV function and morphology can be assessed by cMRI. Despite significantly elevated left and right-sided pressures, preservation of RVEF is generally maintained, and likely serves as a better predictor of outcome than hemodynamics after valvular heart surgery. For patients with preoperative data suggesting RV dysfunction, accurate RVEF by cMRI can give added morphologic and prognostic information.