Predictors of post-operative cardiovascular events, focused on atrial fibrillation, after valve surgery for primary mitral regurgitation.

Aims: Primary mitral regurgitation (PMR) can be considered as a heterogeneous clinical disease. The optimal timing of valve surgery for severe PMR remains unknown. To determine whether unbiased clustering analysis using dense phenotypic data (phenomapping) could identify phenotypically distinct PMR categories of patients. Methods and results: One hundred and twenty-two patients who underwent surgery were analysed, excluding patients with pre-operative permanent atrial fibrillation (AF), were prospectively included before surgery. They were given an extensive echocardiographic evaluation before surgery, and clinical data were collected. These phenotypic variables were grouped in clusters using hierarchical clustering analysis. Then, different groups were created using a dedicated phenomapping algorithm. Post-operative outcomes were compared between the groups. The primary endpoint was post-operative cardiovascular events (PCE), defined as a composite of: deaths, AF, stroke, and rehospitalization. The secondary endpoint was post-operative AF. Data from three phenogroups with different characteristics and prognoses were identified. Phenogroup-1 (67 patients) was the reference group. Phenogroup-2 (33 patients) included intermediate-risk male and smoker patients with heart remodelling. Phenogroup-3 (22 patients) included older female patients with comorbidities (chronic renal failure, paroxysmal AF) and diastolic dysfunction. They had a higher risk of developing both PCE [(hazard ratio) HR = 3.57(1.72-7.44), P < 0.001] and post-operative AF [HR = 4.75(2.03-11.10), P < 0.001]. Pre-operative paroxysmal AF was identified as an independent risk factor for PCE. Conclusion: Classification of PMR can be improved using statistical learning algorithms to define therapeutically homogeneous patient subclasses. High-risk patients can be identified, and these patients should be carefully monitored and may even be treated earlier.

Myocardial constructive work is impaired in hypertrophic cardiomyopathy and predicts left ventricular fibrosis.

BACKGROUND: The estimation of myocardial work by pressure strain loops (PSLs) is a totally new non-invasive approach to assess myocardial performance, and its role in patients with hypertrophic cardiomyopathy is unknown. The aims of the present study are therefore: (a) to compare myocardial work in patients with non-obstructive hypertrophic cardiomyopathy (HCM) and in a subset of age-matched healthy controls and (b) to assess the correlation between myocardial work and left ventricular (LV) fibrosis. DESIGN: Eighty-two patients with non-obstructive HCM (58 ± 14 years) and 20 age-matched healthy subjects (58 ± 7 years, P = 0.99) underwent standard and speckle-tracking echocardiography to assess myocardial dimensions and deformation parameters. PSLs analysis was used to estimate global myocardial constructive work (GCW) and wasted work (GWW). LV fibrosis was estimated at cardiac magnetic resonance (CMR) by qualitative assessment of late gadolinium enhancement (LGE), and significant fibrosis was defined as LGE in ≥2 LV segments. RESULTS: Global constructive work (1599 ± 423 vs 2248 ± 249 mm Hg%, P < 0.0001) was significantly reduced in HCM compared to the control group. No difference was observed in GWW (141 ± 125 vs 101 ± 88 mm Hg%, P = 0.18) and LV ejection fraction (LVEF) (63 ± 13 vs 66 ± 4% P = 0.17) between the two groups. In HCM, GCW was the only predictor of LV fibrosis at multivariable analysis (OR 1.01, 95% CI: 0.99-1.08, P = 0.04). A cutoff value of 1623 mm Hg% (AUC 0.80, 95% CI: 0.66-0.93, P < 0.0001) was able to predict myocardial fibrosis with a good sensitivity and fair specificity (82% and 67%, respectively). CONCLUSIONS: Global constructive work is significantly reduced in HCM despite normal LVEF and is associated with the LV fibrosis as assessed by LGE.

Right ventricular exercise contractile reserve and outcomes after early surgery for primary mitral regurgitation.

OBJECTIVE: To assess if the lack of development of right ventricular (RV) contractile reserve during exercise echocardiography (ex-echo) might be a predictor of postoperative major adverse cardiovascular events (MACEs) in patients with primary mitral regurgitation (pMR) undergoing early surgery. METHODS: Comprehensive resting and ex-echo were performed in 142 asymptomatic patients (58±21 years, 68% men, New York Heart Association functional class ≤2) with isolated severe pMR and preserved left ventricular (LV) function (LV ejection >60%, LV end-systolic diameter <45 mm) undergoing mitral valve replacement (n=20) or repair. Postoperative MACEs were defined as occurrence of atrial fibrillation, stroke, cardiac-related hospitalisation or death. RV function was evaluated at rest in every patient during ex-echo by measuring their tricuspid annular plane systolic excursion (TAPSE) value. RESULTS: After median follow-up of 30 months (IQR 16-60 months), MACEs occurred in 48 (34%) patients. Using Bayesian model averaging, among all the characteristics including the type of surgery, exercise TAPSE (ex-TAPSE) emerged as the most likely predictor of prognosis (HR 0.91, 95% CI 0.86 to 0.96). Other probable predictors were exercise fractional area change (HR 0.02, 95% CI 0.00 to 0.80), male gender (HR 0.40, 95% CI 0.21 to 0.75) and RV basal diameter (HR 1.06, 95% CI 0.98 to 1.14). In the receiver operating characteristic curve analysis, an ex-TAPSE value of <26 mm (sensitivity 73% (95% CI 61 to 84) and specificity of 86% (95% CI 77% to 93%)) defined RV dysfunction. Event-free survival at 5 years was significantly lower in the patient group that exhibited no development of RV contractile reserve during exercise: 43.9% (95% CI 31.3 to 61.4) vs 75.8% (95% CI 64.8 to 88.7). CONCLUSION: Lack of development of exercise-induced RV contractile reserve is a prognostic predictor in patients with severe pMR undergoing early mitral valve surgery.