Early Intervention for Asymptomatic Severe Aortic Stenosis
Is there a difference in outcomes associated with initial aortic valve replacement (AVR) compared to watchful waiting among asymptomatic patients with severe aortic stenosis (AS)?
The CURRENT AS (Contemporary outcomes after sURgery and medical tREatmeNT in patients with severe Aortic Stenosis) registry is a multicenter registry that enrolled 3,815 consecutive patients with severe AS (peak aortic jet velocity >4.0 m/s, or mean aortic pressure gradient >40 mm Hg, or aortic valve area <1.0 cm2) between January 2003 and December 2011. Among 1,808 asymptomatic patients, strategies of initial AVR and of conservative management were chosen in 291 patients and 1,517 patients, respectively. The median duration of follow-up was 1,361 days with 90% follow-up rate at 2 years. A propensity-score matched cohort of 582 patients (291 patients undergoing initial AVR and 291 patients in the conservative group) was developed as the main analysis set for the current report.
Baseline characteristics of the two groups in the propensity-score matched cohort were largely comparable, except for slightly younger age and greater AS severity in the initial AVR group. In the conservative group, AVR was performed in 41% of patients during follow-up. The cumulative 5-year incidences of all-cause death and heart failure hospitalization were significantly lower in the initial AVR group than in the conservative group (15.4% vs. 26.4%, p = 0.009, and 3.8% vs. 19.9%, p < 0.001, respectively). Results from multivariable Cox models in the entire cohort were consistent with those from the propensity-score matched analysis.
The authors concluded that long-term outcome of asymptomatic patients with severe AS was dismal when managed conservatively in real clinical practice, but might be substantially improved by a strategy of early AVR.
Current American Heart Association/American College of Cardiology and European Society of Cardiology guidelines recommend in most cases a strategy of deferring AVR until symptoms emerge among asymptomatic patients with severe AS. At least one smaller observational study found significant outcome advantages associated with early AVR among patients with very severe AS (Kang DH, et al., Circulation 2010;121:1502-9), and another observational study suggests that early AVR (but not AVR using conventional guidelines) might be associated with restoration of normal life expectancy (Brown ML, et al., J Thorac Cardiovasc Surg 2008;135:308-15). The present study is important in that it adds more data supporting early intervention (prior to symptom onset) among patients with severe AS. Although the present study did not include exercise testing to assure that patients were asymptomatic, a practical clinical conclusion might be the following: Patients with truly severe AS might fare better with AVR regardless of symptoms. The onus is on the clinician to either evoke those symptoms by history or exercise testing, or simply refer for AVR as long as the AS is truly severe.
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