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Patients with severe aortic stenosis who undergo transcatheter aortic valve replacement (TAVR) based solely on technical inoperability have lower long-term mortality and better quality of life (QoL) than those judged inoperable for clinical reasons, according to a substudy of the PARTNER trial published online October 23, 2013, ahead of print in the Journal of the American College of Cardiology.

In PARTNER Cohort B, patients with severe, symptomatic aortic stenosis who were deemed unsuitable for surgery were randomized to TAVR with the Sapien valve (Edwards Lifesciences, Irvine, CA) or standard therapy (optimal medical therapy plus balloon valvuloplasty as required). At 1 year, TAVR reduced the rate of all-cause death, the primary endpoint.

For the current subanalysis, investigators led by Raj R. Makkar, MD, of Cedars-Sinai Heart Institute (Los Angeles, CA), looked at 369 TAVR patients, including 175 from the randomized study and 194 from the continued access registry, as well as 181 patients who received standard therapy.

Refining Risk Stratification

TAVR patients were stratified according to whether they were considered inoperable for technical reasons (n = 85; 23%) or clinical reasons (alone or in conjunction with technical factors; n = 284). Technical inoperability was defined as anatomical factors that make surgery either technically impossible or dangerous, such as porcelain aorta, previous bypass graft beneath the sternum, and chest-wall radiation or deformity. Reasons for clinical inoperability included multiple comorbidities (48%), frailty (31%), and severe lung disease (16%).

In addition, the Society of Thoracic Surgeons (STS) score was used to subdivide both clinically and technically inoperable patients into 3 risk categories:

• Low (< 5%): 11.3% and 49.4%, respectively
• Intermediate-high (5-14.9%): 63.0% and 50.6%, respectively
• Very high (≥ 15%): 25.7% and none, respectively

Aside from a marginally shorter postprocedure hospital stay (5.34 ± 2.18 days vs. 5.86 ± 1.97 days; P = 0.04), there were no differences in periprocedural or 30-day outcomes between the technically and clinically inoperable arms.

Mortality Almost Halved in ‘Technical’ Group

However, at 2 years, all-cause mortality in the technically inoperable group was just over half that in the clinically inoperable group (23.3% vs. 43.8%; P = 0.001). Regardless, for the endpoints of all-cause mortality, cardiac mortality, and repeat hospitalization, both groups of inoperable TAVR patients fared better than those who received standard therapy (table 1).

Table 1. Kaplan-Meier Outcomes at 2 Years

Of the clinically inoperable patients, 34 also had technical reasons for inoperability. These patients had a similar 2-year mortality (43.8%) to those who were inoperable for clinical reasons alone (43.8% vs. 43.3%; P = NS), but they experienced more emergent conversion to open surgery (5.9% vs. 0.4%; P = 0.003), late stroke or TIA (22.2% vs. 8.9%; P = 0.048), and MI (6.7% vs. 0.4%; P = 0.0043) than those who were inoperable for clinical reasons alone.

In the clinically inoperable group, patients with a low STS score had less all-cause and cardiovascular mortality than those in the higher STS categories.

In addition, clinical inoperability was associated with increased baseline risk for severe symptomatic heart failure compared with technical inoperability (HR 1.14; 95% CI 1.04-1.25; P < 0.0001). At 1 year, the condition was present in 24.6% of clinically inoperable patients vs. 10.6% of technically inoperable patients (P = 0.02). Even after adjusting for baseline heart failure, follow-up QOL scores were higher in the technically inoperable group compared with the clinically inoperable group.

In a multivariable model, higher STS score and clinical inoperability were both independent predictors of all-cause mortality (P = 0.0466 and P = 0.0166, respectively).

In a telephone interview with TCTMD, Ted Feldman, MD, of Evanston Hospital (Evanston, IL), said the new data help researchers move beyond a simple STS score for stratifying patients and “zero in on TAVR-specific risk assessment.”

The difference between technically and clinically inoperable patients can be summed up as “having a pretty good body wrapped around a bad heart compared with having a bad body wrapped around a bad heart,” he added. 

When Is TAVR Futile?

In an accompanying editorial, Olaf Wendler, MD, PhD, and Rafal Dworakowski, MD, PhD, both of King’s College Hospital (London, United Kingdom), say data showing that some clinically inoperable patients face a grim future even with TAVR can help identify those for whom the procedure may be futile.

Dr. Feldman acknowledged that it is not uncommon for clinicians to counsel patients with very high STS scores and multiple comorbidities against undergoing TAVR because net benefit seems unlikely. “But right now, that’s a judgment; it’s not quantified,” he said. Patient frailty is “one piece of the puzzle,” he added, but is not necessarily decisive.  

Moreover, Dr. Feldman emphasized, in the PARTNER study even very sick patients reaped a survival benefit from TAVR compared with standard therapy. “And based on my clinical experience, they get a tremendous quality-of-life boost,” he observed. “The best measure of that is the improvement in repeat hospitalization.”

On the other end of the risk spectrum, Drs. Wendler and Dworakowski observe that the excellent outcomes in technically inoperable patients “make it most likely that patients with a combination of symptomatic [aortic stenosis] and these surgical/technical characteristics, even if they are younger and otherwise carry a low risk for [surgical valve replacement], would benefit from [TAVR] treatment.”

Note: Study author Martin B. Leon, MD, of Columbia University Medical Center (New York, NY), is a faculty member of the Cardiovascular Research Foundation, which owns and operates TCTMD.

2. Wendler O, Dworakowski R. TAVI in patients unsuitable for surgery: A prognostic benefit for all [editorial]? J Am Coll Cardiol. 2013;Epub ahead of print.

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• For Inoperable Patients, TAVR Carries Benefits but Raises Lifetime Costs