Severe aortic valve stenosis and the consequences of transcatheter and surgical aortic valve replacement: A cardiovascular magnetic resonance study.

Background: Severe symptomatic aortic stenosis (AS) heralds a poor prognostic outlook and significant co-morbidity, with valve replacement the only definitive cure. Transcatheter aortic valve implantation (TAVI) has developed as an alternative to the standard treatment of surgical aortic valve replacement (SAVR) in high-risk or inoperable AS patients. The clinical and cost effectiveness of TAVI compared to SAVR requires further investigation.
Methods: A prospective study of sixty seven TAVI and twenty seven SAVR patients, recruited from September 2009 to September 2011. Baseline assessments included a cerebral and cardiovascular magnetic resonance scan (1.5 Tesla MRI system) and the completion of two health surveys (EQ 5D and SF 12). Follow-up MRI was performed at 5±2 days (cerebral MRI) and 6 months (cardiovascular MRI) post AVR. Health status was assessed at 30 days, 6 months and one year. A cost-effectiveness analysis was performed using a 10 year Markov model with deterministic and probabilistic sensitivity analyses.
Results: TAVI and SAVR resulted in similar levels of ventricular reverse remodelling. TAVI had a greater reduction in valvular impedance (21±8mmHg vs. 35±13mmHg, p=0.017) and myocardial fibrosis (10.9±6 % vs. 8.5±5%, p=0.03). Cerebral emboli occurred in 77% of TAVI patients. Age (r=0.37, p=0.042), severity of atheroma (r=0.91, p<0.001) and catheterisation time (r=0.45, p=0.02) were predictors of cerebral infarcts. HRQOL significantly improved over 12 months (PCS, p=0.02; EQ-5D, p=0.02; VAS, p=0.01 and SF6D p=0.03). Male gender (SF6D, p=0.01) and increased operator experience (PCS, EQ5D and VAS, p<0.05) predicted an improvement in HRQOL. Despite greater procedural costs, TAVI was cost-effective compared to SAVR over the 10 year model horizon (costs £52,593 vs. £53,943 and QALYs 2.81 vs. 2.75) indicating that TAVI dominated SAVR.
Conclusions: TAVI has comparable cardiac and health benefits to SAVR, but greater cerebral complications. TAVI is likely to represent a clinical and cost effective alternative to SAVR.