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OBSERVANT: Surgery superior to first-generation TAVR at 5 years in real-world cohort
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SAN DIEGO — Among older patients with severe aortic stenosis at low or intermediate risk, surgical aortic valve replacement was associated with lower rates of all-cause mortality and rehospitalization for HF compared with transfemoral transcatheter aortic valve replacement using first-generation devices, according to 5-year findings from the OBSERVANT trial presented at TCT 2018.
The propensity-score matched study, which enrolled a cohort of real-world patients undergoing surgical AVR or TAVR at Italian hospitals between December 2010 and June 2012, also demonstrated that rates for all-cause mortality were comparable between groups at 1 year; however, survival curves diverted at 2 to 3 years before rising to significance at 4 years, Marco Barbanti, MD, from Policlinico-Vittorio Emanuele Hospital, University of Catania, Italy, said during a presentation.
Barbanti and colleagues analyzed data from 650 patients who underwent surgical AVR (mean age, 80 years; 60% women; 25% with diabetes) and 650 patients who underwent TAVR (mean age, 81 years; 59% women; 25% with diabetes) matched for numerous variables, including previous PCI, frailty score, mitral valve regurgitation, peripheral arteriopathy and previous vascular surgery. All patients were admitted to hospitals with a diagnosis of severe, symptomatic aortic stenosis requiring interventional treatment. Administrative follow-up occurred via linked databases.
At 5 years, surgical AVR was associated with less risk for all-cause mortality vs. TAVR (35.8% vs. 44.5%; HR = 1.38; 95% CI, 1.12-1.69). Outcomes for 5-year MACCE, defined as death, stroke, MI or revascularization via PCI or CABG, also favored the surgical AVR arm, Barbanti said, mainly driven by mortality (42.5% vs. 54%; HR = 1.35; 95% CI, 1.11-1.63).
Observed trends for rehospitalization for HF (HR = 1.19; 95% CI, 0.98-1.43) and any cardiac cause (HR = 1.12; 95% CI, 0.94-1.33) favored the surgery arm at 5 years but did not reach significance, he noted.
“We can argue regarding the reasons for re-hospitalization ... but I think the data for mortality are very strong, so I’m very confident this is true,” Barbanti said during a panel discussion after the presentation. “It was not easy for me to present [these data], to be honest, because I really believe in the procedure. But, I think it is fair to bring these data to the community.”
There were no between-group differences for stroke (P = .318) or redo aortic valve replacement, Barbanti said. Compared with the surgery arm, the rate of pacemaker implantation was more than double in the TAVR arm at 1 year (18.5% vs. 7.3%; P < .001) and 5 years (23.9% vs. 10.2%; P < .001), Barbanti said.
In a discussion after the presentation, Barbanti noted that the OBSERVANT analysis was conducted during the early stages of TAVR in Italy with a group of complex patients. The high rate of pacemaker implantation, as well as patient frailty, that was not assessed in depth with the most appropriate tools, may also have influenced the 5-year findings, he said, and residual confounding due to unrecognized risk factors cannot be ruled out when assessing the findings.
“This study also included people with very bad features for [TAVR] — very nasty calcifications — so there is mixture here of a real-world patient population treated with early-generation devices in centers that were just starting [TAVR], so with no large [procedure] volume,” Barbanti said.
The ongoing OBSERVANT II study, Barbanti said, will assess outcomes in patients with severe, asymptomatic aortic stenosis receiving new-generation TAVR devices since December 2016 to better understand how new-generation devices mitigate the differences in outcomes recorded in the OBSERVANT study.
“These [OBSERVANT] findings are potentially important if substantiated by ongoing randomized and observational trials, including the OBSERVANT II trial, using the new-generation [TAVR] devices,” Barbanti said. “I think this [new study] will address the many of the limitations in the current study.” – by Regina Schaffer
Reference:
Barbanti M, et al. Keynote Interventional Studies VI: Structural Heart Interventions I. Presented at: TCT Scientific Symposium; Sept. 21-25, 2018; San Diego.
Disclosure: Barbanti reports he received consultant fees or honoraria from Biotronik and Edwards Lifesciences.