Impact of left ventricular hypertrophy late after aortic valve replacement for aortic stenosis on cardiovascular morbidity and mortality

https://doi.org/10.1016/j.ijcard.2005.05.050Get rights and content

Abstract

Aims

The goal of this study was to assess the prevalence of left ventricular (LV) hypertrophy in patients with aortic stenosis late (> 6 months) after aortic valve replacement and its impact on cardiac-related morbidity and mortality.

Methods and results

In a single tertiary centre, echocardiographic data of LV muscle mass were collected. Detailed information of medical history and angiographic data were gathered. Ninety-nine of 213 patients (46%) had LV hypertrophy late (mean 5.8 ± 5.4 years) after aortic valve replacement. LV hypertrophy was associated with impaired exercise capacity, higher New York Heart Association dyspnoea class, a tendency for more frequent chest pain expressed as higher Canadian Cardiovascular Society class, and more rehospitalizations. 24% of patients with normal LV mass vs. 39% of patients with LV hypertrophy reported cardiac-related morbidity (p = 0.04). In a multivariate logistic regression model, LV hypertrophy was an independent predictor of cardiac-related morbidity (odds ratio 2.31, 95% CI 1.08 to 5.41), after correction for gender, baseline ejection fraction, and coronary artery disease and its risk factors. Thirty seven deaths occurred during a total of 1959 patient years of follow-up (mean follow-up 9.6 years). Age at aortic valve replacement (hazard ratio 1.85, 95% CI 1.39 to 2.47, for every 5 years increase in age), coexisting coronary artery disease at the time of surgery (hazard ratio 3.36, 95% CI 1.31 to 8.62), and smoking (hazard ratio 4.82, 95% CI 1.72 to 13.45) were independent predictors of overall mortality late after surgery, but not LV hypertrophy.

Conclusions

In patients with aortic valve replacement for isolated aortic stenosis, LV hypertrophy late after surgery is associated with increased morbidity.

Introduction

In patients with long-standing aortic stenosis, left ventricular (LV) mass increases and ventricular geometry changes in order to preserve the relation between intraventricular pressure and systolic wall stress.[1], [2] LV hypertrophy is a result of cellular myocardial hypertrophy and structural alternations of the extracellular matrix (i.e. interstitial fibrosis). Myocardial hypertrophy and interstitial fibrosis impair the diastolic function of the LV by increasing its stiffness and delaying its relaxation [3]. After successful aortic valve replacement, LV pressure and thereby LV systolic wall stress are substantially reduced [4]. As a consequence, regression of LV hypertrophy can be expected during the ensuing months.

In the general population, LV hypertrophy is a risk factor for cardiovascular morbidity and mortality independent of its aetiology [5]. In patients with aortic stenosis and LV hypertrophy, there are few data on the fate of patients with increased LV mass late after aortic valve replacement. A recent report of a small patient group suggested an increased mortality (23% mortality over a mean follow-up of 40 months) in patients with persistent LV hypertrophy after aortic valve replacement for aortic stenosis [6].

The current study was designed to assess the prevalence of LV hypertrophy late after aortic valve replacement in a large patient cohort and to test the hypothesis of increased cardiovascular morbidity and mortality related to LV hypertrophy despite successful aortic valve replacement.

Section snippets

Patient selection

All transthoracic echocardiographic studies performed at our institution between 1992 and 1998 were reviewed for the following four criteria: (i) aortic valve replacement for predominant aortic stenosis; (ii) no previous or concomitant replacement of another heart valve; (iii) sufficient echocardiographic image quality to allow determination of LV mass; (iv) the echocardiographic study was performed at least 6 months postoperatively. Each patient and/or the family doctor was located. In 5 cases

Patient characteristics

Patient characteristics are summarized in Table 1. Ninety-nine of 213 patients (46%) operated for aortic stenosis had LV hypertrophy > 6 months after aortic valve replacement. Patients with LV hypertrophy were 4 years older at the time of aortic valve replacement than patients with normal LV mass at follow-up (p = 0.03). They were treated more frequently with beta blocking agents than patients with normalized LV mass (27% vs. 11%, p = 0.02). Otherwise cardiac medication and clinical characteristics

Discussion

In nearly half of our patients with isolated aortic valve stenosis undergoing aortic valve replacement, LV mass is increased late after surgery independent of a history of arterial hypertension. In these patients, LV hypertrophy is associated with increased exertional dyspnoea and reduced exercise capacity. Overall mortality in patients > 6 months after replacement of a stenotic aortic valve was mainly related to age at surgery, coexisting coronary artery disease and smoking.

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