Using transcatheter aortic valve replacement (TAVR) to treat bicuspid aortic valve stenosis (AS) can be significantly less effective than using TAVR to treat tricuspid AS, according to the findings of a new study presented at the annual meeting of the American College of Cardiology and published simultaneously in the Journal of the American College of Cardiology.
“There is a paucity of data comparing the clinical outcomes of TAVR in bicuspid and tricuspid AS,” wrote the authors of the study, led by Sung-Han Yoon, MD, of the Cedars-Sinai Heart Institute in Los Angeles. “Given the increasing frequency of bicuspid AS in younger patients, coupled with the worldwide shift of treating younger and lower–surgical-risk patients with TAVR, the clinical outcomes of TAVR in bicuspid AS warrants special attention.”
Dr. Yoon and his coinvestigators began by collecting data from the Bicuspid AS TAVR registry, which began in December 2013 and contains information on patients from 33 health care centers around the world. Patients who entered the database prior to the initiation of the study were screened retroactively, while those who joined afterward were followed prospectively.
Eventually, 561 bicuspid AS patients were included in the study, out of a total of 576 that were treated between April 2005 and May 2016. Twelve centers also performed tricuspid AS, with investigators able to collect data on 5,900 patients who underwent the procedure during the same period of time. Ultimately, 4,546 were included in the study.
“Given the differences in baseline clinical, echocardiographic, and procedural characteristics between patients with bicuspid and tricuspid AS, propensity-score matching was applied to identify a cohort of patients with similar baseline characteristics, and thus clinical outcomes of propensity-score matched cohorts were compared,” the authors explained.
Variables used when establishing propensity-score matches included age, sex, New York Heart Association functional class III or IV, the presence of certain conditions such as chronic lung disease and diabetes, and procedural data. Dr. Yoon and his colleagues were able to create 546 pairs of matched patients between the bicuspid AS and tricuspid AS cohorts.
The devices implanted in subjects also underwent classification by the investigators, either as early-generation or new-generation devices. The former consisted of Sapien XT and CoreValve devices, while Sapien 3, Lotus, and Evolut R devices comprised the latter classification. A total of 320 bicuspid AS and 321 tricuspid AS patients received early-generation implant devices, with 226 and 225 patients, respectively, receiving new-generation devices.
Devices were less successful in bicuspid AS patients versus tricuspid AS patients: 85.3% and 91.4%, respectively (P = .002). Furthermore, a significantly higher rate of bicuspid AS patients had to be converted to surgery, compared with tricuspid AS patients: 2.0% and 0.2%, respectively (P = .006). Early-generation implant devices had considerably higher rates of issues in bicuspid AS patients, with 4.5% of those receiving Sapien XT experiencing aortic root injury and 0% of tricuspid AS patients with the same device having the same problem (P = .015). Bicuspid AS patients who received the CoreValve implant experienced paravalvular leak 19.4% of the time, compared with 10.5% in tricuspid AS patients (P = .02); these leaks were classified as “moderate to severe.”
“In addition, patients with bicuspid AS had more frequent second valve implantation (11.6% vs. 2.9%; P = .002) [and] subsequent lower device success rates (72.1% vs. 86.0%; P = .002) than those with tricuspid AS when receiving the CoreValve,” the authors noted. “However, there were no significant differences in these adverse procedural events between groups when receiving the Sapien 3 and Lotus.”
There were also no significant differences between the bicuspid and tricuspid AS in terms of mortality rates. At 2 years postoperation, all-cause mortality rates were 17.2% for bicuspid AS patients and 19.4% for tricuspid AS patients, regardless of the type of device implant (P = .28). When comparing early and new-generation devices, results were similarly nonsignificant: early-generation bicuspid vs. tricuspid AS all-cause mortality rates were 14.5% and 13.7%, respectively (P = .80) and 4.5% vs. 7.4% (P = .64) for new-generation devices.
“The present study is the first large-scale study that compared the safety, efficacy, and clinical outcomes of TAVR in patients with bicuspid and tricuspid AS,” Dr. Yoon and his colleagues noted, adding that, in regards to the disparity in device effectiveness, “The present study showed that the initial attempt of device advancement succeeded in overcoming the procedural limitations in tricuspid AS and now go beyond the challenges in treating bicuspid AS.”
No funding source for this study was disclosed. Dr. Yoon did not report any relevant financial disclosures, but several coauthors disclosed potentially relevant financial conflicts.