Patients with asymptomatic, severe aortic stenosis (AS) are presumed to have a benign prognosis. Current guidelines therefore do not recommend aortic valve replacement (AVR) for isolated, asymptomatic, severe AS. The aim of this study was to explore the natural history of patients with severe AS advised against surgery due to lack of symptoms.
Patients who were referred for diagnostic evaluation for severe AS were identified through a search in the hospital database. We reviewed the medical records of every patient with the ICD-10-code for AS (I35) between Dec 1st, 2002 and Dec 31st, 2016. Clinical data, biochemistry and imaging data were procured for the patients categorised as asymptomatic and 100 age- and gender matched patients referred to AVR. By March 2017, mortality data were obtained from the national Norwegian Cause of Death Registry. This study was approved by the Regional Ethical Committee, which waived the need for patient consent because of the retrospective nature of the study.
Among the 3454 patients with the code for AS, 2341 patients were evaluated by the heart team for possible AVR due to severe AS during the period in question. 1953 patients were referred to AVR. 388 patients received conservative treatment due to either a lack of symptoms (n=114), patient refusal (n=49) or a high risk-benefit ratio or because they had comorbidities presumed to reduce life expectancy significantly (n=225). The asymptomatic patients had a median age of 83.4 (IQR: 76.5-87.0). 42 % were male. The peak aortic jet velocity was 4.4±0.8 m/s, and the aortic valve opening area was 0.68±0.16 cm2. During a mean duration of follow up of 4.0±2.5 years (median 4.1 years, IQR: 2.10-5.4), 72 of the 114 patients died (63%). Survival at 1, 2 and 3 years for the asymptomatic patients was 88%, 75% and 63% respectively, compared with 91%, 82% and 77% in those who were referred to AVR (p<0.001) (Figure 1). 28 patients received AVR at a median 1.6 (IQR:1,1,-2.8) years after they were initially advised against surgery. When censoring the asymptomatic patients at the time of AVR, 1, 2 and 3 years survival was 88%, 72% and 57%. Cox regression analysis identified Troponin T as an independent predictor of mortality in patients with asymptomatic severe AS, p= 0.029. Age, valvular disease severity, NT-ProBNP, diabetes and coronary artery disease were not predictors of mortality.
Patients with severe AS who were advised against surgery due to lack of symptoms, had significantly higher mortality than patients referred for AVR. Troponin T was an independent predictor of mortality. Our results suggest that in patients with severe AS, AVR should be considered even in "asymptomatic" patients, particularly if Troponin T is elevated.