WASHINGTON – Patient gender was the only factor that significantly affected stroke risk during the first year following transcatheter aortic valve replacement, according to an analysis of data from nearly 6,000 patients in the U.S. registry for these procedures.
The 1-year outcome results also showed six factors that significantly affected 1-year mortality following transcatheter aortic valve replacement (TAVR): age, gender, severe chronic obstructive pulmonary disease (COPD), end-stage renal disease, TAVR access route, and risk score.
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Dr. David R. Holmes, Jr.
"Identification of these associations is essential for developing risk-prediction models, and will aid in patient-selection criteria for TAVR," said Dr. David R. Holmes Jr., who presented the results at the annual meeting of the American College of Cardiology. "The factors we have identified will be used to develop models that patients and physicians can use for deciding on appropriate treatment for aortic stenosis."
One-year outcomes for 5,980 of the first U.S. Medicare patients to undergo TAVR since it arrived on the U.S. market in November 2011 came from records of the Centers for Medicare & Medicaid Services (CMS) for patients enrolled during November 2011–July 2013 in the Society of Thoracic Surgeons (STS)/American College of Cardiology (ACC) Transcatheter Valve Therapy Registry.
The registry’s findings also continued to generate interest in the risk level of the first wave of U.S. patients undergoing routine TAVR. The 5,980 registry patients with 1-year outcome data had a median PROM (STS Predicted Risk of Operative Mortality) score of 7% prior to treatment, showing that a substantial number of U.S. TAVR patients had STS scores below the device’s labeled minimum risk score of 8%.
"Sometimes you look at a patient and say, ‘I don’t care what the STS score is, I think this patient will have problems’ " with surgical valve replacement, said Dr. Holmes, an interventional cardiologist and professor of medicine at the Mayo Clinic in Rochester, Minn. "You need two thoracic surgeons who say that the patient is high risk" and should undergo TAVR regardless of a low STS PROM score, "and that is what carries the day" in terms of securing Medicare coverage for the procedure, he said.
The STS and ACC began the registry at the request of the Food and Drug Administration and to satisfy a CMS mandate to track all Medicare TAVR patients. The first wave of patients entered the registry when the Sapien valve system marketed by Edwards became the first TAVR device approved for routine U.S. use in patients with severe aortic stenosis judged ineligible for surgical valve replacement. In October 2012, the FDA approved the same device as an alternative to surgery for "high-risk" but operable patients, generally defined as those with an STS PROM of at least 8%. The PARTNER trial that led to FDA approval of the Sapien system for operable patients had a minimum STS PROM score threshold for enrollment of 10%, and enrolled patients had an average score of 11.8% (N. Engl. J. Med. 2011;364:2187-98).
Last November, researchers running the registry reported in-hospital and 30-day outcomes for 7,710 of the first TAVR patients who entered during November 2011–May 2013 (JAMA 2013;310:2069-77). They collected 1-year outcomes by linking the registry to data from the CMS Administrative Claims Center.
The results showed a 1-year mortality of 26%, and a 1-year stroke rate of 4%.
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Dr. David E. Kandzari
"Mortality was fairly consistent with results from trials; however, the stroke rate was lower, which might result from how strokes are identified" in a registry compared with more structured follow-up in trials, commented Dr. David E. Kandzari, director of interventional cardiology and chief scientific officer at the Piedmont Heart Institute in Atlanta. "It’s also important that the mortality rate [in the registry] occurred with a high, 36% rate of nontransfemoral access. The higher mortality seen in the registry with nontransfemoral access cannot be discounted. This is probably the highest event rate we will see" with TAVR, Dr. Kandzari predicted. "We can expect outcomes will continue to improve" with advances in TAVR technique and technology.
In multivariate modeling, gender was the only analyzed factor that significantly linked with the 1-year stroke rate. Men had a relative 34% lower stroke rate than women. Women are known to have higher stroke rates than men following other catheter procedures, such as arrhythmia ablations, though the reasons why remain unclear, Dr. Holmes noted.
The relative rates for the six factors that each had a significant link to mortality were a 36% increased mortality for patients aged 85-94 years, compared with those younger than 75 years; a 19% increased rate in men, compared with women; a 41% increased rate in patients with severe COPD, compared with patients with no or mild COPD; an 81% increased rate in dialysis patients, compared with patients with normal creatinine levels; a 42% higher rate with nontransfemoral access, compared with transfemoral access; and a 44% higher mortality among patients with an STS PROM score of 8%-15%, compared with patients with a score of less than 8%.