Evaluation of left ventricular function and mass after Medtronic Freestyle versus homograft aortic root replacement using cardiovascular magnetic resonance.

BACKGROUND AND AIM OF THE STUDY: Regression of left ventricular hypertrophy (LVH) after aortic valve replacement has traditionally been measured by echocardiography. However, cardiovascular magnetic resonance (CMR) can be used to measure left ventricular function and mass more accurately and reproducibly. This translates into fewer patients being needed to demonstrate significant changes. The study aim was to demonstrate the feasibility of using CMR to measure left ventricular mass index (LVMI) and function in patients from a prospective randomized trial, and to compare homografts with the Medtronic Freestyle root replacement.

METHODS: Among 23 patients recruited, 17 had LVMI and function (end-diastolic volume (EDV), end-systolic volume (ESV), stroke volume (SV) and ejection fraction (EF)) measured pre- and postoperatively using CMR (eight homograft, nine Freestyle).

RESULTS: Significant regression of LVH was seen in both groups one year postoperatively (homograft LVMI 145+/-44 g/m2 preoperative versus 83+/-23 g/m2 one year postoperatively; Freestyle LVMI 140+/-28 g/m2 versus 93+/-21 g/m2, respectively). At six months there was significant regression in the xenograft group (from 140+/-28 to 106+/-22 g/m2; p <0.05) and a trend towards regression in the homograft group (from 145+/-44 to 103+/-25 g/m2; p = NS). There was also a trend towards a reduction in EDV, ESV and SV, and an increase in EF over one year in both groups.

CONCLUSION: Regression of LVH was measured using CMR in patients after aortic root replacement and coronary implantation with the homograft and Medtronic Freestyle root replacement. Despite the small number of patients studied, it was possible to demonstrate the extent and pattern of regression of left ventricular mass in the two groups.