Aortic Stenosis
Risk Stratification in Asymptomatic Aortic Stenosis Raluca Dulgheru,1,2
Sara Hana Weisz,1,3 Julien Magne1
and Patrizio Lancellotti1
1. Heart Valve Clinic, University of Liege, Department of Cardiology, University Hospital Sart Tilman, Liege, Belgium; 2. University of Medicine and Pharmacy ‘Carol Davila’, Bucharest, Romania; 3. Second University of Naples, Department of Cardiology, Naples, Italy
Abstract
Aortic stenosis is now the most frequent valvular heart disease in developed countries with a steadily increase in prevalence. The necessity of surgery in symptomatic patients is well established. However, the need for surgery in asymptomatic patients remains controversial. The identification of several factors (predictors of outcome) that may help selection of patients who are most likely to benefit from early elective surgery is challenging and of clinical importance.
Keywords Valve, aortic stenosis, risk assessment, asymptomatic, outcome
Disclosures: None of the authors have any conflicts of interest to declare. Acknowledgements: Raluca Dulgheru has received a one-year research scholarship from the Romanian Society of Cardiology. Julien Magne is Research Associate at the Fonds de la Recherche Scientifique-FNRS (Brussels) and has received grants from the Fonds Léon Fredericq (Liège) and the Fond pour la Chirurgie Cardiaque (Brussels). Received: 25 January 2012 Accepted: 22 March 2012 Citation: European Cardiology, 2012;8(2):120–4 Correspondence: Patrizio Lancellotti, Department of Cardiology, University Hospital Sart Tilman, 4000 Liege, Belgium. E:
plancellotti@chu.ulg.ac.be
Aortic stenosis (AS) is the most frequent valvular heart disease in developed countries,1
Role of Echocardiography with a steady increase in prevalence as the
population ages. Progressive degeneration of aortic leaflets,2 age-related and enhanced by common cardiovascular risk factors,3
is
the most frequent aetiology. Besides ‘calcific’ AS (the valvular disease of the elderly), the second most frequent aetiology is bicuspid calcific AS, followed by rheumatic AS.
Irrespectively of the aetiology, the natural history of AS is theoretically characterised by a long-standing asymptomatic period, lasting several decades, during which progressive left ventricular (LV) outflow-tract obstruction occurs. During this period, the risk of sudden death is relatively low (less than 1 % per year), which has led to AS being considered as a benign disease, even when severe.4
In patients with
asymptomatic severe AS, prophylactic surgery is thus not recommended and current guidelines advocate delaying aortic valve replacement (AVR) until symptoms develop.
However, this ‘wait for symptoms’ strategy requires a careful follow-up, which is not always applicable to all patients, and prompt identification of the onset of symptoms. Indeed, death may occur soon after symptoms develop or, even worse, without any preceding symptoms, and if the waiting period for surgery is too long. Ideally, the surgical decision should be made sufficiently late to outweigh the surgical risk and early enough to avoid irreversible damage of the LV myocardium.5–7
Individual risk stratification could thus help to identify asymptomatic AS and who would be more likely to benefit from early elective surgery (see Table 1), with the goal of reducing mortality and avoid unnecessary intervention. Current guidelines consider surgery as reasonable in asymptomatic patients with reduced (<50 %) left ventricular ejection fraction (LVEF) and in patients who exhibit symptoms during an exercise test.8
120
Echocardiography has a key role in the evaluation of patients with asymptomatic AS. It allows the visualisation of valve morphology, the study of valve haemodynamics with quantification of AS severity and the evaluation of LV function and of the interaction between the left ventricle, the valve and the arterial system (see Figure 1).
The Valve
Among echocardiographic parameters, peak aortic jet velocity (Vmax), valve calcification severity and the rate of haemodynamic progression
are able to identify patients at higher risk of symptom development.
In numerous studies, Vmax was described as a useful predictor of outcome.4,9,10
with a Vmax >4 m/s had a two-year event-free survival less than 30 %, while patients with a Vmax <3 m/s had a five-year event-free survival >80 %.9
Otto et al. found that a higher Vmax was related to a worse outcome over the whole spectrum of the disease severity. Patients
In a large population with haemodynamically significant AS, Pellikka et al. established a cut-off value of 4.5 m/s to identify patients at higher risk of adverse outcome.4
Lancellotti et al.
also supported these findings in a subset of 163 patients with asymptomatic moderate-to-severe AS. A cut-off value of 4.4 m/s identified patients at higher risk of cardiovascular events (symptom onset, death, AVR) during a mean follow-up of 19 months.10 et al. studied the outcome of asymptomatic patients with very severe
Rosenhek
AS (Vmax >5 m/s) and showed that Vmax is still one of the best predictors of outcome.11
They compared patients with severe AS (Vmax
between 4 and 5 m/s) to patients with very severe AS (Vmax >5 m/s), and also patients with Vmax between 5 and 5.5 m/s to patients with Vmax >5.5m/s. They showed that event-free survival in AS gets significantly worse as Vmax increases.11
Interestingly, in this study, aortic valve area (AVA) was not a predictor of outcome, probably © TOUCH BRIEFINGS 2012
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