Abstract
Aims
Optimal timing of valve implantation in patients with severe aortic stenosis (AS) is under debate, considering the subjective nature of symptom onset. We aimed to investigate the pre-procedural value of routinely available cardiac biomarkers in predicting postoperative long-term outcome in a large cohort undergoing either surgical or transcatheter aortic valve implantation.
Methods
The Tyrolean Aortic Stenosis Study-2 (TASS-2) group, a consortium of four university hospital centers in Austria, analysed pre-procedural high-sensitivity troponin T (hsTnT) and N-terminal pro brain natriuretic peptide (NT-proBNP) plasma levels in 3595 patients admitted for valve implantation because of severe aortic stenosis since 2007.
Results
Transcatheter aortic valve implantation was performed in 1517 (42.2%) of patients. During a median follow-up of 2.93 (1.91–4.92) years, 919 patients (25.6%) died, among them 556 (15.5%) due to cardiovascular causes. In multivariate cox regression analysis - adjusting for STS risk score (intermediate risk 4–8%, high risk >8%), degree of left ventricular systolic dysfunction (ejection fraction 30–50% and <30%), atrial fibrillation, sex, age, renal function, COPD, arterial hypertension, diabetes mellitus, concomitant significant coronary artery disease and type of procedure (surgical aortic valve replacement or transcatheter aortic valve implantation) - pre-procedural hsTnT as well as NT-proBNP plasma levels were strong independent predictors for postoperative survival: hazard ratio [HR] 1.82, 95% confidence interval [CI] 1.07–3.11, P=0.028 for mildly to moderately elevated hsTnT (14–50 ng/l); HR 2.80, CI 1.61–4.89, P<0.001 for severely elevated hsTnT (>50 ng/l); HR 1.38, CI 1.06–1.81, P=0.018 for mildly to moderately elevated NT-proBNP (defined by an increase of up to threefold of age- and sex-corrected normal range); HR 1.68, CI 1.29–2.18, P<0.001 for severely elevated NT-proBNP (defined by an increase of more than threefold of age- and sex-corrected normal range). For direct comparison of these two biomarkers a second cox regression model was conducted including only hsTnT and NT-proBNP revealing the strength of hsTnT as a predictive biomarker: HR 2.20, 95% CI 1.29–3.77, P=0.004 for minimally elevated hsTnT (5–13.99 ng/l); HR 4.05, CI 2.41–6.82, P<0.001 for mildly to moderately elevated hsTnT (14–50 ng/l); HR 8.63, CI 5.07–14.70, P<0.001 for severely elevated hsTnT (>50 ng/l); HR 1.47, CI 1.13–1.91, P=0.004 for mildly to moderately elevated NT-proBNP; HR 1.96, CI 1.54–2.51, P<0.001 for severely elevated NT-proBNP.
Conclusion
hsTNT and NT-proBNP strongly predict long-term postoperative survival in patients with severe AS admitted for valve implantation.
Acknowledgement/Funding
This work was supported by the Tiroler Wissenschaftsförderung: grant number TWF-2017-1-5, GZ: UNI-0404-2104