What’s New? Brief Reports on Clinical Research
T. Harahwa, (London, UK), P. Avanzas (Oviedo, Spain)
There are limited data on the long-term clinical outcomes and bioprosthetic-valve function after transcatheter aortic-valve replacement (TAVR). In the PARTNER 2 trial , Makkar et al.1 sought to compare the long-term clinical outcomes and bioprosthetic-valve function five years after TAVR, compared to surgical valve replacement. The authors report a 5-year follow-up analysis of clinical outcomes, valve function and quality of life measures in 2032 patients with severe aortic stenosis recruited from 57 centres across Canada and USA with severe, symptomatic aortic stenosis and at intermediate risk for surgery. Patients were randomised to either undergo TAVR (1011 of 2032, 49.8%) or surgery (1021 of 2032, 50.2%) with a bioprosthetic valve. Patients assigned to the TAVR group were also stratified according to intended transfemoral (76.3%) or transthoracic (23.7%) access. The primary end-point of the trial was death from any cause or disabling stroke. Other end-points considered were repeat hospitalisation (procedure, valve or heart failure-related), aortic valve reintervention by repeat TAVR or surgery, NYHA functional class, quality-of-life measures, and echocardiographic assessments of aortic-valve area, aortic valve gradients and paravalvular regurgitation.
At 5 years, data were available for 920 patients in the TAVR group (920 of 1011, 91.0%) and for 831 in the surgery group (831 of 1021, 81.4%). Considering the primary endpoint, there were no significant differences between the TAVR group and the surgical group (47.9% vs. 43.4%; hazard ratio, 1.09; 95% Confidence Interval [CI], 0.95-1.25; P=0.21). The incidence of death or disabling stroke was higher in the TAVR group compared to the surgical group in the transthoracic-access route (59.3% vs. 48.3%; hazard ratio 1.32; 95% CI, 1.02-1.71). Additionally, more patients in the TAVR group were found to have at least mild paravalvular aortic regurgitation (33.3% vs. 6.3%), along with more frequent repeat hospitalisations (33.3% vs. 25.2%; hazard ratio, 1.28; CI, 1.07-1.53) and more frequent aortic-valve reinterventions (3.2% vs. 0.8%; hazard ratio, 3.28; CI, 1.32-8.13) when compared to the surgery group. Both the TAVR and surgery groups showed improvements in health status at the 5-year mark with an average increase from the baseline KCCQ-QS score of 19.6 and 20.5 points respectively.
These findings at 5 years are in the line of those previously reported at one and two years in the PARTNER trial2,3. Whilst the findings of this study are consistent with previous findings supporting the use of TAVR as an alternative to surgical aortic-valve replacement, this study is very important as it offers new insights into long-term outcomes of TAVR when compared to surgical aortic-valve replacement, a topic poorly reported in the literature.
The main limitations of this study were firstly, both in the TAVR and surgery groups there were 5-year missing data in some patients for specific end-points. Although the authors performed sensitivity analyses trying to overcome this limitation, some findings may still have been biased. Secondly, the participants in this study represent a very specific population, i.e. mean age of 81 years old and of intermediate surgical risk, thus the findings may not be applicable to younger patients or those with lower surgical risks. Finally, bioprosthetic-valve failure rates increase with time, therefore 5 years may not be an adequate time to assess long-term valve function. Further follow-up may be required to reliably assess the durability of bioprosthetic valves in TAVR in comparison to surgery.
References
- Makkar RR, Thourani VH, Mack MJ, et al. Five-Year Outcomes of Transcatheter or Surgical Aortic-Valve Replacement. N Engl J Med. 2020; 382:799-809. doi: 10.1056/NEJMoa1910555.
- Miller DC, Blackstone EH, Mack MJ, et al. Transcatheter (TAVR) versus surgical (AVR) aortic valve replacement: Occurrence, hazard, risk factors, and consequences of neurologic events in the PARTNER trial. The Journal of Thoracic and Cardiovascular Surgery. 2012; 143(4): 832-843. doi: 10.1016/j.jtcvs.2012.01.055.
- Kodali SK, Williams MR, Smith CR, et al. Two-Year Outcomes after Transcatheter or Surgical Aortic-Valve Replacement. N Engl J Med. 2012; 366: 1686-1695. doi: 10.1056/NEJMoa1200384.