Clinical Pearls & Morning Reports
Although one third to one half of patients with severe aortic stenosis are asymptomatic at the time of diagnosis, appropriate timing of intervention for these patients remains controversial. Kang et al. conducted the RECOVERY trial, which compared long-term clinical outcomes of early surgical aortic-valve replacement with those of a conservative care strategy based on current guidelines in asymptomatic patients with very severe aortic stenosis. Read the Original Article here.
Q: Is it considered safe to delay surgery in patients with severe aortic stenosis until symptoms develop?
A: The decision to perform surgery in an asymptomatic patient requires careful weighing of the risks of early aortic-valve replacement against those of observation. In patients with asymptomatic severe aortic stenosis, it has generally appeared to be relatively safe to follow a watchful waiting strategy and delay surgery until symptoms develop. However, this conservative care strategy is also associated with a risk of sudden death, denial or late reporting of symptoms by patients, irreversible myocardial damage, and an increase in surgical risk while waiting for symptoms to develop.
Q: How was “very severe aortic stenosis” defined in the RECOVERY trial?
A: The authors screened consecutive patients who were 20 to 80 years of age and who presented with very severe aortic stenosis, which was assessed by means of transthoracic echocardiography. In accordance with the 1998 American College of Cardiology–American Heart Association guidelines and a traditional definition of severe aortic stenosis, the authors defined very severe aortic stenosis as an aortic-valve area of 0.75 cm2 or less with either a peak aortic jet velocity of 4.5 m per second or greater or a mean transaortic gradient of 50 mm Hg or greater.
A: In an intention-to-treat analysis including all the trial patients, 1 of 73 patients assigned to early surgery (1%) and 11 of 72 patients assigned to conservative care (15%) died from cardiovascular causes (hazard ratio, 0.09; 95% confidence interval [CI], 0.01 to 0.67). The cumulative incidence of the primary end point (operative mortality or death from cardiovascular causes during the follow-up period), as calculated with the use of a Kaplan–Meier analysis, was 1% at both 4 and 8 years in the early-surgery group, as compared with 6% at 4 years and 26% at 8 years in the conservative-care group (P=0.003). A total of 5 deaths from any cause (7% of the patients) occurred in the early-surgery group and 15 deaths from any cause (21%) occurred in the conservative-care group (hazard ratio, 0.33; 95% CI, 0.12 to 0.90). The cumulative incidence of death from any cause was lower in the early-surgery group than in the conservative-care group (4% vs. 10% at 4 years and 10% vs. 32% at 8 years).
A: The authors state that the risk-benefit ratio may be shifted toward a benefit of early surgery in this trial involving patients with very severe aortic stenosis because the risk of waiting increases according to the severity of aortic stenosis. The benefit of early surgery may be relatively smaller in asymptomatic patients with less severe aortic stenosis. Exercise testing is reasonable to confirm the absence of symptoms in asymptomatic patients with severe aortic stenosis, but it was performed only selectively in this trial. The small numbers of trial patients and primary end-point events constitute an important limitation of the trial.