Author + information
- Matteo Pagnesi, MD,
- Mauro Chiarito, MD,
- Giulio G. Stefanini, MD,
- Luca Testa, MD,
- Bernhard Reimers, MD,
- Antonio Colombo, MD and
- Azeem Latib, MD∗ ()
- ↵∗Interventional Cardiology Unit, San Raffaele Scientific Institute, Via Olgettina 60, 20132 Milan, Italy
Transcatheter aortic valve replacement (TAVR) has revolutionized the treatment of patients with severe, symptomatic aortic stenosis. Randomized controlled trials (RCT) have shown similar outcomes of TAVR versus surgical aortic valve replacement (SAVR) (1–5). In particular, the recently published SURTAVI (Surgical Replacement and Transcatheter Aortic Valve Implantation) and PARTNER (Placement of Aortic Transcatheter Valves) 2 cohort A trials reported a similar risk of death from any cause or disabling stroke in intermediate-risk patients undergoing TAVR or SAVR (3,4).
Considering the release of these new data (4), we performed an updated study-level meta-analysis of published RCTs directly comparing TAVR versus SAVR in accordance with PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) guidelines. The pre-specified primary endpoint was the risk of death or disabling stroke at 1 year as reported by the included trials in the as-treated or modified intention-to-treat populations. Risk for bias among included RCTs was evaluated with the Cochrane assessment tool. Risk ratio with 95% confidence intervals was calculated using a fixed-effects model, given the lack of heterogeneity across trials. We used the Cochrane Q statistics and I2 values to test heterogeneity across studies. Analyses were performed using Stata version 14.1 (Stata Corp., College Station, Texas).
Four RCTs (1–4) were included for a total of 5,002 patients randomly allocated to TAVR (n = 2,592) or SAVR (n = 2,410). The NOTION (Nordic Aortic Valve Intervention) trial was excluded because the composite of death or disabling stroke was not reported (5). The overall risk of bias was low in all included studies. As summarized in Figure 1, TAVR was associated with a lower risk of death or disabling stroke at 1 year (risk ratio: 0.87; 95% confidence interval: 0.76 to 0.99; p = 0.03) with no evidence of heterogeneity across studies (I2 = 0%). Sensitivity analyses indicated consistent results irrespective of device used (balloon-expandable vs. self-expandable devices; pinteraction = 0.51) and patients’ surgical risk profile (high-risk vs. intermediate-risk; pinteraction = 0.89). Risk estimates were also consistent after exclusion of each included RCT.
Individual RCTs were designed to demonstrate noninferiority of TAVR to SAVR and were not powered to evaluate superiority in terms of clinical outcomes. Only the U.S. CoreValve High Risk trial reported a significantly lower risk of our pre-specified primary endpoint in the TAVR group (2), whereas the PARTNER 2 trial detected a significant reduction only in the transfemoral access TAVR subgroup (3). Pooling the evidence derived from 4 pivotal RCTs with a total of 5,002 patients, our meta-analysis suggests that a less-invasive transcatheter approach (TAVR with any access site) could provide a significant clinical benefit over a standard surgical strategy in patients with severe, symptomatic aortic stenosis. However, consequences of TAVR-specific adverse events (e.g., residual aortic regurgitation, need for pacemaker implantation, overt or covert cerebral injury, vascular complications) and durability of bioprosthetic transcatheter valves over time could affect long-term outcomes and therefore requires future careful assessment.
The main limitations of our meta-analysis are the lack of patient-level data and the inherent limitations of included trials (unplanned withdrawals in the surgery group, limited use of the latest-generation transcatheter bioprostheses, lack of long-term follow-up, lack of assessment of subclinical valve-leaflet thrombosis).
In conclusion, this meta-analysis indicates that TAVR might be associated with a significantly lower risk of death or disabling stroke at 1 year, irrespective of the type of valve implanted and the surgical risk of treated patients.
Please note: Dr. Stefanini has received consultant fees from Edwards Lifesciences. Dr. Latib is a consultant for Medtronic; and has received honoraria from Abbott Vascular. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
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