Valve Size and Stenosis Predict Survival in Patients with Transcatheter Valve Implantation

Small surgical valve size and stenosis were predictors of lower survival among patients who underwent transcatheter valve-in-valve implantation inside failed surgical bioprosthetic valves, according to a recent study [JAMA. 2014;312:162-170].

“Patients with failed bioprosthetic valves are conventionally treated with [reoperative] surgery. Transcatheter valve-in-valve is a less invasive approach,” said Danny Dvir, MD, St. Paul’s Hospital, Vancouver, Canada, in an interview with First Report Managed Care.

The popularity of the procedure, however, will likely lead to an increase in patients developing degenerated bioprostheses. The Valve-in-Valve International Data (VIVID) registry was instated in December 2010 to collect data on valve-in-valve procedures, especially those executed with self-expandable (CoreValve^® Transcatheter Aortic Valve Replacement Platform) and balloon-expandable (Edwards SAPIEN XT Transcatheter Heart Valve) devices.

“The VIVID registry included high-risk patients who had many comorbidities and high risk scores for early mortality with conventional [reoperative] surgery,” said Dr. Dvir, who, along with his colleagues, collected data from cases performed between 2007 and May 2013 (retrospectively for cases performed before the creation of VIVID and prospectively thereafter), from a total of 55 centers with 459 patients. The main outcome measures included survival, stroke, and New York Heart Association (NYHA) functional class.

The study’s researchers used the Society of Thoracic Surgeons score and the LogEuro SCORE to predict patient operative mortality after conventional surgical valve replacement. The Kaplan-Meier method was used to calculate time-to-event curves and the log-rank statistic was used to compare results. Median follow-up time was 301 days. The mechanism of failure was stenosis in 181 patients (39.4%), regurgitation in 139 patients (30.3%), and a combination of the 2 in 139 patients (30.3%), which was evaluated according to American Society of Echocardiography criteria.

Results showed that patients in the stenosis group had a higher 30-day mortality rate (10.5% vs 4.3% in the regurgitation group and 7.2% for the combined group; P=.04). No differences were found between the self-expandable and balloon-expandable device groups in terms of mortality or stroke rates. The majority of patients (92.6%) were NYHA functional class 1/2, and a total of 8 patients (1.7%) experienced a major stroke by day 30.

The overall 1-year Kaplan-Meier survival rate was 83.2% (95% confidence interval [CI], 80.8-84.7). Patients in the stenosis group had worse 1-year survival (76.6%; 95% CI, 68.9-83.1) compared to the regurgitation group (91.2%; 95% CI, 85.7-96.7) and the combined group (83.9%; 95% CI, 76.8-91). Patients with small valves (≤21 mm) also showed worse 1-year survival (74.8%; 95% CI, 66.2-83.4) compared to patients having intermediate-sized (>21 mm and <25 mm) valves (81.8%; 95% CI, 75.3-88.3) or large (≥25 mm) valves (93.3%; 95% CI, 85.7-96.7). No differences in survival were observed between the self-expandable or balloon-expandable device groups. The incidence of patient-prosthetic mismatch also did not affect 1-year survival. Most patients (86.2%) remained NYHA functional class 1/2.

Some limitations of the study included a lack of echocardiographic data immediately after surgical implantation as well as a lack of other parameters that can affect clinical outcomes of structural aortic valve disease, such as left ventricular mass index, diastolic function, ischemic cardiomyopathy, and frailty.

“The study results have many clinical implications for a wide range of specialties, including family practitioners and internal medicine physicians [who] treat patients with failed bioprosthetic valves, interventional cardiologists, and cardiothoracic surgeons,” Dr. Dvir said. “Attempts to implant large bioprostheses during aortic valve surgery may improve outcome, as we see that the surgical valve size has strong impact on the success of valve-in-valve when these valves fail years later.”—Mary Mihalovic