Biological versus prosthetic ring in mitral-valve repair: enhancement of mitral annulus dynamics and left-ventricular function with pericardial annuloplasty at long term

Objective: The effects of different annuloplasty rings on mitral annulus dy namics and left-ventricular (LV) function after mitral-valve repair (MVR) a re still controversial. This study sought to compare biological versus pros thetic rigid rings for annular remodelling in MVR at long term. Methods: Fo rty-four consecutive patients were retrospectively enrolled. All patients h ad isolated posterior-leaflet prolapse and underwent identical surgical mit ral-valve reconstruction (quadrangular resection of the posterior leaflet a ssociated with annuloplasty). Twenty-three patients underwent mitral annulo plasty with an autologous pericardial ring (group I), whereas 21 patients h ad MVR with a Carpentier-Edwards rigid ring (group II). No differences exis ted between the groups in terms of pre-operative patient profile. Post-oper ative LV systolic indices have been assessed by two-dimensional echocardiog raphy at rest and during supine bicycle exercise. Mihal annular motion has been examined by means of the extent of mitral annulus systolic excursion ( MASE), as measured in four longitudinal LV segments (anterior, inferior, se ptal and lateral). Mean and peak trans-mitral flow velocities (TMFV) have b een also evaluated by continuous-wave Doppler, Results: The mean follow-up did not differ between the groups, those being 41 +/- 12 months in group I (range17-65 months) and 46 +/- 15 months in group II (range 23-83 months), respectively. Post-operative echocardiographic study did not show significa nt mitral regurgitation at rest: or at peak exercise in any patient. ANOVA analysis for repeated measures showed a significant interaction in peak TMF V (F-(1,F-42) = 5.23; P = 0.03), and in left-ventricular ejection fraction (LVEF; F-(1,F-42) = 7.61, P = 0.01). The analysis of contrasts showed a sig nificant increase in TMFV in both groups (group I from 1.22 +/- 0.22 to 1.7 9 +/- 0.32 m/s, t = -8.8, P < 0.0001; and group II from 1.19 +/- 0.17 to 1. 96 +/- 0.33 m/s, a = - 12.8, P < 0.0001). Recruitment of LVEF reserve durin g exercise was observed only in group I (from 59.5 +/- 6 to 65.8 +/- 6%, t = -3.95, P < 0.005), whereas no substantial change occurred in LV performan ce in group II, A trend towards better MASE at all the studied longitudinal segments at rest and during exercise was observed in group I. No minor or major calcifications have been observed on pericardial rings. Conclusions: The autologous pericardium seems to be superior to rigid prosthetic rings f or annuloplasty in MVR since it provides more favourable mitral annulus dyn amics and preserves LV function during stress conditions. Effective and dur able annular remodelling with the autologous pericardium is achieved up to 6 years from surgery, with no echocardiographic sign of degeneration in the long term. Further studies are required to compare biological versus flexi ble prosthetic rings in MVR. (C) 2000 Elsevier Science B.V. All rights rese rved.