What is the right time to replace a stenotic aortic valve in asymptomatic patients?

 

It is one of the most controversial clinical situations in cardiology: when is the right moment to indicate valve replacement in patients with asymptomatic aortic stenosis?

Many studies have been published in this field, but despite the amount of data collected, there is still no unanimous agreement on the precise moment in which it is necessary to refer a patient to surgeon for valve replacement.

Recently, a new trial tried to settle the doubt. Published in the New England Journal of Medicine, it compared two parallel strategies: immediate referral to valve replacement or conservative care. According to their results, the strategy that leads to early surgery seems to offer important clinical advantages.

The guidelines of the European Society of Cardiology on Valvulopathies, dated 2017, affirms that studies do not provide convincing data to support the recommendation of early valve replacement, even in patients with very severe asymptomatic aortic stenosis.

Instead, they establish that the decision to operate asymptomatic patients requires a careful evaluation of the risk-benefit ratio, with an indication for asymptomatic patients with depressed systolic function of the left ventricle, not due to other causes, and in patients who develop symptoms during exercise test.

This new trial, carried out by a group of North Korean researchers, included 145 subjects with severe aortic stenosis and randomized them to early surgery or conservative care. A severe stenosis was defined by a valvular area less than or equal to 0.75 cm2 and with an aortic jet greater than or equal to 4.5 m/sec or a mean trans-aortic gradient greater than or equal to 50 mmHg.

The study endpoint was a composite of intraoperative death or within 30 days, or death from cardiovascular causes during the follow-up period, which had a median duration of 6.2 years.

All patients were asymptomatic and had a mean age of 63 and 65 years in the conservative care and early-surgery group, respectively.

Aortic stenosis was due to a bicuspid valve in 61% of cases and to a degenerative disease in 33% of cases. In 3% of cases the aetiology was rheumatic.

During surgery, patients received in equal proportions a mechanical or biological valve.

The study did not record any cases of intraoperative mortality. The endpoint occurred in one patient in the early-surgery group and in 15% of the patients included in the conservative care group. Even death from any cause was more frequent in the latter group.

It is interesting to observe how, during the follow-up, 74% of the patients assigned to the conservative care group underwent surgical valve replacement. Only one case was treated by a transcatheter valve implantation.

This study, performed in a population of Asian subjects, seems to testify in favor of an early surgical treatment for valve replacement, even in asymptomatic patients.

This is not a resolutive study, but it can provide useful indications, to identify more precisely which patients will most benefit from a more aggressive treatment.

This post is also available in: Chinese (Simplified)

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