Left ventricular diastolic function after restrictive mitral ring annuloplasty in chronic ischemic mitral regurgitation and its predictive value on outcome and recurrence of regurgitation.

BACKGROUND: This study was aimed at exploring the predictive value of diastolic function on clinical outcome and recurrence of ischemic mitral regurgitation following combined undersized mitral annuloplasty (UMRA) and coronary artery bypass grafting (CABG). METHODS: Two hundred-thirty-four patients with chronic ischemic mitral regurgitation (CIMR) who survived combined UMRA and CABG between September 2001 and September 2007, were divided into four groups on the basis of baseline deceleration time (DT) and systolic-diastolic pulmonary venous flow ratio (S/D): Group 1, normal (n=48), Group 2, impaired relaxation (n=61), Group 3, pseudonormal (n=60) and Group 4, restrictive (n=65). Echocardiograms were performed, preoperatively, at discharge and at follow-up appointments (early, 6 months [interquartile range, IQR] 3-8 months; late, 38 months [IQR17-53 months]). RESULTS: Early mortality rate was highest in the restrictive group (9.2%, p<0.001). In addition 6-year actuarial survival was significantly lower in Group 4 (p=0.025). At late follow-up, among patients in Group 4, 58.4% (n=38) had an MR grade >or=2 (p<0.001). Furthermore, DT<140 ms and S/D<0.80 were independent predictors of early (p<0.001 and 0.004, respectively) and late (both p<0.001) death. Finally DT<140 ms was the only diastolic independent predictor of MR recurrence (p<0.001). CONCLUSIONS: In patients with CIMR undergoing combined CABG and UMRA restrictive LV diastolic filling pattern is an important preoperative marker of high early and late death and recurrence of MR.

Prognostic value of Doppler-derived mitral deceleration time on left ventricular reverse remodelling after undersized mitral annuloplasty.

AIMS: This study was aimed at exploring the predictive value of Doppler-Derived Mitral Deceleration Time (DT) on left ventricular reverse remodelling (LVRR) in patients with chronic ischaemic mitral regurgitation (CIMR) undergoing combined undersized mitral annuloplasty (UMRA) and coronary artery bypass grafting (CABG). METHODS AND RESULTS: Two hundred and fifteen patients undergoing combined UMRA and CABG for CIMR between September 2001 and September 2007 in our Institution were divided into four groups on the basis of baseline DT: Group 1, normal (n = 48), Group 2, impaired relaxation (n = 61), Group 3, pseudonormal (n = 50), and Group 4, restrictive (n = 56). Echocardiograms were performed, pre-operatively, at discharge and at follow-up appointments (100% complete, early, median 6 months [interquartile range 4-8 months]) and late, median 38 months (17-61 months). Left ventricular reverse remodelling, defined as a reduction in ESV > 15%, occurred in 95.7, 96.3, 88.3, and 0% in Groups 1, 2, 3, and 4, respectively (P < 0.001). Logistic regression analysis showed that DT

Paracrine effects of transplanted myoblasts and relaxin on post-infarction heart remodelling.

In the post-infarcted heart, grafting of precursor cells may partially restore heart function but the improvement is modest and the mechanisms involved remain to be elucidated. Here, we explored this issue by transplanting C2C12 myoblasts, genetically engineered to express enhanced green fluorescent protein (eGFP) or eGFP and the cardiotropic hormone relaxin (RLX) through coronary venous route to swine with experimental chronic myocardial infarction. The rationale was to deliver constant, biologically effective levels of RLX at the site of cell engraftment. One month after engraftment, histological analysis showed that C2C12 myoblasts selectively settled in the ischaemic scar and were located around blood vessels showing an activated endothelium (ICAM-1-,VCAM-positive). C2C12 myoblasts did not trans-differentiate towards a cardiac phenotype, but did induce extracellular matrix remodelling by the secretion of matrix metalloproteases (MMP) and increase microvessel density through the expression of vascular endothelial growth factor (VEGF). Relaxin-producing C2C12 myoblasts displayed greater efficacy to engraft the post-ischaemic scar and to induce extracellular matrix re-modelling and angiogenesis as compared with the control cells. By echocardiography, C2C12-engrafted swine showed improved heart contractility compared with the ungrafted controls, especially those producing RLX. We suggest that the beneficial effects of myoblast grafting on cardiac function are primarily dependent on the paracrine effects of transplanted cells on extracellular matrix remodelling and vascularization. The combined treatment with myoblast transplantation and local RLX production may be helpful in preventing deleterious cardiac remodelling and may hold therapeutic possibility for post-infarcted patients.