Report Provides Snapshot of Initial Commercial TAVR Experience

In the years after approval, TAVR is increasingly being used in lower-risk—but still elderly and sick—patients in the United States, with declines over time in rates of bleeding, vascular complications, and mortality.

Additional results from the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy (TVT) Registry show that procedure itself is changing, as well, with growing use of moderate sedation instead of general anesthesia and femoral access with percutaneous techniques.

The findings “have provided important scientific information on early outcomes of TAVR compared with other selected clinical experiences and pivotal randomized trials,” David Holmes Jr, MD, of the Mayo Clinic (Rochester, MN), and colleagues write in a Journal of the American College of Cardiology paper published online November 30, 2015.

“Future reports,” they continue, “will be able to quantify outcomes over subsequent years, as well as trends in short- and long-term outcomes related to new technologies, changing patient selection criteria, and evolving clinical management strategies, and may facilitate comparative assessment of different devices.”

The TVT Registry was started in December 2011 to fulfill the requirements of the Centers for Medicare & Medicaid Services (CMS) for coverage with evidence development. Following reports of initial in-hospital and 1-year outcomes from the registry, the current paper provides a look at current US practice and trends over the past few years. It includes data on 26,414 TAVR procedures performed using commercially available devices in the United States between 2012 and 2014. In 2014, 348 centers in 48 of the 50 states were performing TAVR. Devices included Sapien and Sapien XT (Edwards Lifesciences) and CoreValve (Medtronic).

During the study period, there were statistically significant but “clinically insignificant” changes in baseline patient characteristics over time. Mean patient age was 82 years, and the procedures were roughly evenly split between men and women. Multiple comorbidities were common, and most patients had NYHA class III/IV symptoms (82.5%) and were frail (81.6%), defined as a slow 5-meter walk time. Median Kansas City Cardiomyopathy Questionnaire score at baseline—39.1 in 2014—indicated poor self-reported health status, with reduced function and quality of life.

There was a trend toward declining median STS score at baseline, which went from 7.05 in 2012 to 6.69 in 2014 (P < .0001 for trend), probably related to growing use of the procedure in high-risk patients after it was initially confined to inoperable or prohibitive-risk populations, according to the authors. Indeed, TAVR was performed in mostly extreme-risk patients in 2012-2013 (86%), whereas only 6% of patients were considered to have high risk. In 2014, 39% of patients were classified as extreme risk and 56% as high risk.

Procedure Is Changing

TAVR was typically done in a hybrid operating room suite during the study period, with only 10% to 13% done in a cath lab. “This may change as the technology improves with decreasing catheter sizes and may shift the procedure in the future to more frequent performance in a catheterization laboratory,” Holmes and colleagues note.

Over time, transesophageal echocardiography became less common and CT angiography more common for the assessment of preprocedural aortic annulus size.

Although general anesthesia was used in the vast majority of cases throughout the study, moderate sedation became more frequent (from 1.6% to 5.1%; P < .0001 for trend), a finding attributed to the use of smaller catheters.

Femoral access using percutaneous techniques gained favor, accounting for 66.8% of procedures in 2014.

Device implantation success remained high during the study period, and was 97.4% in 2014. Using Valve Academic Research Consortium (VARC)-1 criteria, device success, combining correct anatomic position and satisfactory intended valve performance, was 92.7%.

Complications, Mortality Drop

About one-third of patients in the most recent experience had a complication in the hospital, but procedure-related cardiac complications occurred in only 1.9%.

The most common intraprocedural cardiac complication was the need for a new pacemaker, which increased from 7.5% in 2012-2013 to 10.5% in 2014 (P < .0001 for trend). “This is most likely the result of expanding the types of prostheses implanted to include CoreValve, which has been associated with a higher incidence of conduction system abnormalities,” the authors say.

Rates of life-threatening intraprocedural complications and device migration or embolization were low.

There was a decrease over time in VARC-defined major bleeding or life-threatening or disabling bleeding, as well as in vascular complications (P < .0001 for trends). “These may continue to decrease as the technology matures, with smaller access sheaths and catheters and improved approaches using vascular access closure devices,” the investigators predict. “That will be an important metric to follow because vascular complications have been associated with increased morbidity/mortality.”

The rate of stroke, which has been a concern following TAVR, remained stable throughout the study period at a little over 2%.

Mean postprocedure length of stay fell, reaching 6.2 days in 2014. “[T]he use of more moderate sedation, more transfemoral access, vascular closure devices for true percutaneous entry, and potentially, the shift to a catheterization laboratory environment with recovery in a cardiac care unit (rather than a surgical intensive care unit) can be expected to further decrease length of stay, making the procedure more cost-efficient,” the authors write.

At the same time, unadjusted in-hospital mortality declined from 5.3% in 2012-2013 to 4.4% in 2014 (P = .0004 for trend).

Varied Uses of TVT Registry

The TVT Registry has many uses that have already been realized or are being planned, according to Holmes and colleagues. Those include the development of a TAVR-specific risk prediction algorithm for in-hospital mortality, FDA-mandated device surveillance, quality-improvement initiatives, and studies on the link between procedure volume and outcome as well as on societal issues regarding delivery of care.

“The predominant theme of the current report is that the field of TAVR is exceptionally dynamic,” Michael Reardon, MD, and Neal Kleiman, MD, of Houston Methodist DeBakey Heart & Vascular Center (Houston, TX), write in an accompanying editorial.

The findings indicate “extremely encouraging” patient outcomes, as well as a shift toward lower-risk patients over time, they say. The study does not completely alleviate “early concern about ‘creep’ of the procedure into inappropriately low-risk patient populations,” the editorialists note, but it does show that “patients remain elderly and at high risk, and are symptomatic and frail. These observations suggest that patient selection for TAVR in the United States has remained reasonable, with excellent efficacy and continued safety.”

Moving forward, the registry will provide information on the durability of valves, Reardon and Kleiman say. “Although 5-year results from the PARTNER trial show no indication of structural valve degeneration, surgical experience has shown that in many cases, structural valve degeneration can become apparent fairly abruptly after this period,” they note.

In addition, the TVT Registry will prove useful for examining the relationship between operator experience, institutional volume, and clinical outcomes; for evaluating rare, unusual occurrences after TAVR when combined with other national registries; and for answering important unanswered questions, “particularly in regard to antithrombotic therapies,” they predict.

Sources: 
1. Holmes DR Jr, Nishimura RA, Grover FL, et al. Annual outcomes with transcatheter valve therapy: from the STS/ACC TVT Registry. J Am Coll Cardiol. 2015;Epub ahead of print.
2. Reardon MJ, Kleiman NS. Watching a procedure evolve: sequential findings from the TVT Registry [editorial]. J Am Coll Cardiol. 2015;Epub ahead of print.

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