Prognostic determinants in severe aortic regurgitation

Since the last two decades, aortic valve (AV) repair has emerged as an alternative for AV replacement, as surgery for patients with severe aortic regurgitation (AR). The aim of this thesis is to reevaluate the appropriateness of the guidelines for this new type of surgery, in particular to examine whether it might allow earlier treatment for the management of asymptomatic patients with normal ejection fraction. My works first show that the AV repair improves prognosis of patients. Subsequently we evaluated post operative survival after AV repair according to the guidelines and showed an interest to assess the benefit of an early surgery in asymptomatic patients. Despite that no benefit of an early surgery has been shown, we finally explored and measured a new parameter, the extracellular volume by cMR, able to assess myocardial fibrosis and which should add information in the management of asymptomatic patients with severe AR.(BIFA - Sciences biomédicales et pharmaceutiques) -- UCL, 201

Predictive value of the heart rate reserve in patients with permanent atrial fibrillation treated according to a strict rate-control strategy.

Atrial fibrillation (AF) patients treated according to a rate-control strategy seem to have excellent outcomes as long as their ventricular response is kept low. However, the stringency of the rate control to adopt with pharmacologic agents is not clearly defined. In particular, the clinical importance of preserving a heart rate (HR) reserve (HRR) during exercise has not yet been investigated

Inference in a survival cure model with mismeasured covariates using a simulation-extrapolation approach

In many situations in survival analysis, it may happen that a fraction of individuals will never experience the event of interest: they are considered to be cured. The promotion time cure model takes this into account. We consider the case where one or more explanatory variables in the model are subject to measurement error, which should be taken into account to avoid biased estimators. A general approach is the simulation-extrapolation algorithm, a method based on simulations which allows one to estimate the effect of measurement error on the bias of the estimators and to reduce this bias. We extend this approach to the promotion time cure model. We explain how the algorithm works, and we show that the proposed estimator is approximately consistent and asymptotically normally distributed, and that it performs well in finite samples. Finally, we analyse a database in cardiology: among the explanatory variables of interest is the ejection fraction, which is known to be measured with error

Inference in a Survival Cure Model with Mismeasured Covariates using a SIMEX Approach

In many situations in survival analysis, it may happen that a fraction of individuals will never experience the event of interest: they are considered to be cured. The promotion time cure model is one of the survival models taking this feature into account. We consider the case where one or more explanatory variables in the model are subject to measurement error. This error should be taken into account in the estimation of the model, to avoid biased estimators. A general approach that exists in the literature is the SIMEX algorithm, a method based on simulations which allows one to estimate the e_ect of mea- surement error on the bias of the estimators and to reduce this bias. We extend the SIMEX approach to the promotion time cure model. We explain how the algorithm works, and we show that the proposed estimator is consistent and asymptotically normally distributed. We also show via simulations that the sug- gested method performs well in _nite samples. Finally, we analyze a database in cardiology: among the explanatory variables of interest is the ejection fraction, which is known to be measured with error. There are supplementary materials online for this paper

Long-term follow-up of DDD and VDD pacing : a prospective non-randomized single-centre comparison of patients with symptomatic atrioventricular block.

This prospective non-randomized single-centre registry compared clinical outcome, pacing parameters, and long-term survival in patients receiving VDD or DDD pacemaker (PMs) for symptomatic atrioventricular (AV) block

Very Long Term Survival After Mitral Repair Vs Replacement. A Propensity Score Analysis Of A Large, Prospective, Multicenter International Registry

Background: Despite the absence of randomized studies comparing mitral valve (MV) repair and replacement, international guidelines strongly recommend MV repair as the optimal surgical treatment for severe degenerative mitral regurgitation (dMR). Yet, the level of evidence supporting these recommendations is low, owing to the lack of available clinical trial data. In this context, analysis of large multicenter registries becomes critical. Objective: To compare very long-term survival among patients (pts) undergoing MV repair versus replacement for the treatment of severe dMR using the technique of propensity score (PS) matching to reduce bias in non-randomized cohorts. Methods: The Mitral Regurgitation International DAtabase (MIDA) is a prospective multicenter registry that includes 2,569 consecutive pts with dMR, who were recruited in 6 tertiary centers (France, Italy, Belgium, and the United States) between 1980 and 2005. Among these, we identified 1,922 pts who underwent mitral surgery, including 1,709 MV repairs and 213 MV replacements. We compared operative mortality and overall survival in both the entire study population and in 615 PS-matched (2:1) pts. Results: Operative mortality was lower after MV repair than after MV replacement, both in the entire population (2 vs 7%; p=0.001) and in the PS-matched pts (4 vs 8%; p=0.04). Similarly, 20-year survival was better after MV repair than after MV replacement, both in the entire population (46% [95% CI, 39%-52%] vs 23% [95% CI, 14%-32%], p<0.001) and in the PS-matched pts (41% [95% CI, 28%-54%] vs 24% [95% CI, 14%-33%], p<0.001). Similar results were obtained in pts aged < 65 years (p<0.005), 65-74 years (p<0.001) and ≥ 75 years (p<0.001). Conclusions: Among registry pts with dMR, performance of MV repair resulted in lower operative mortality and greater long-term survival compared to MV replacement, thus supporting current international recommendations

The clinical impact of valvular heart disease in a population-based cohort of subjects aged 80 and older

BACKGROUND: In our ageing society, valvular heart diseases (VHD) have become an increasing public health problem. However, the lack of studies describing the impact of these diseases on the outcome of very old subjects makes it difficult to appreciate their real clinical burden. METHODS: Prospective, observational, population-based cohort study in Belgium. Five hundred fifty six subjects aged 80 years and older were followed up for 5.1 ± 0.25 years for mortality and 3.0 ± 0.25 years for hospitalization. Echocardiograms were performed at baseline. The Cumulative Illness Rating Scale (CIRS) was calculated for each subject. RESULTS: The prevalence of moderate-to-severe VHD was 17 % (n = 97). Mitral stenosis was more prevalent in women and an age-dependent increase of the prevalence of severe aortic stenosis was seen. The overall disease burden was higher in participants with VHD (median CIRS 3 [IQR 3-5] vs 4 [IQR 3-6] (P = 0.008)). Moderate-to-severe VHD, and more specifically mitral stenosis and aortic stenosis, was found to be an independent predictor of both all-cause (HR 1.42 (95 % CI 1.04-1.95)) and cardiovascular mortality (HR 2.13 (95 % CI 1.38-3.29)). Moderate-to-severe VHD was also found to be an independent predictor of the need for a first unplanned hospitalization (HR 1.43 (95 % CI 1.06-1.94)). CONCLUSIONS: A high prevalence of moderate-to-severe VHD was found in the very old. Moderate-to-severe VHD was identified as an independent risk factor for all-cause and cardiovascular mortality and as well for unplanned hospitalizations, independent of other structural cardiac abnormalities, ventricular function and major co-morbidities