Long-term results after aortic valve replacement for bicuspid or tricuspid valve morphology in a Swedish population

Abstract

Objectives: Our goal was to study long-term observed and relative survival after first-time aortic valve replacement surgery with or without concomitant coronary artery bypass surgery with reference to valve morphology (i.e. bicuspid vs tricuspid).

Methods: Consecutive patients (n = 5086) from 3 Swedish hospitals, operated on between 1 January 2005 and 31 December 2016, were included. The 30-day mortality (n = 116, 2.3%) was excluded from the analysis of long-term observed and relative survival (n = 4970). Observed survival was analysed using Cox regression. Relative survival was calculated as the ratio between observed and expected survival based on data from the general Swedish population, matched for age, sex and calendar year. Risk factors for death were explored using multivariable analysis.

Results: During the follow-up (median 4.7 years) period, 1157 (23%) patients died. Observed survival excluding 30-day mortality was 96.6%, 82.7% and 57.6% after 1, 5 and 10 years. Compared with the general Swedish population, the relative 1-, 5- and 10-year survival rates were 99.0%, 97.5% and 89.0%. Bicuspid morphology was independently associated with higher observed and relative long-term survival. Renal dysfunction, diabetes, chronic obstructive pulmonary disease, heart failure, smoking and atrial fibrillation were associated with higher long-term mortality. Combined surgery was not associated with higher observed or relative mortality.

Conclusions: Patients with a bicuspid morphology had better prognosis, matching that of the general population. With increased age, long-term relative survival compared favourably with survival in the general Swedish population. Adding coronary artery bypass surgery to an aortic valve replacement procedure did not affect long-term outcome.

Keywords: Aortic stenosis; Aortic valve replacement; Bicuspid valve; Observed survival; Relative survival.

Figure 1:

Flow diagram of patient inclusion process. TAVI: transcatheter aortic valve implantation.

Figure 2:

Long-term observed and relative survival following aortic valve surgery. Comparison of long-term observed (continuous line) and relative survival (dotted line) for patients undergoing aortic valve replacement (n = 4970). The 95% confidence intervals for estimated survival are provided as well as the number at risk (n) at the start of even follow-up years.

Figure 3:

Long-term observed and relative survival following aortic valve surgery stratified on valvular morphology. Long-term observed (continuous line) and relative (dotted line) survival for patients undergoing aortic valve replacement (n = 4970), shown for tricuspid valves (black line) and bicuspid valves (red), separately. Number at risk (n) at the start of even follow-up years.

Figure 4:

Predictors of long-term mortality in patients undergoing aortic valve replacement surgery. Estimated hazard ratios (HR, black dots) and relative mortality ratios (hollow dots) for predictor variables of long-term observed and relative mortality, respectively. Corresponding 95% confidence intervals are provided. COPD; chronic obstructive pulmonary disease; GFR; glomerular filtration rate. *Never smoker was used as the reference category (HR = 1.0).