CME Author: Zeena Nackerdien
Study Authors: Harun Kundi, Jeffry J. Popma, et al.
Target Audience and Goal Statement:
Cardiologists, heart valve surgeons, emergency department physicians, and internists
To learn more about the assessment of whether hospitals with better outcomes for surgical aortic valve replacement (SAVR) subsequently improved transaortic valve replacement (TAVR) outcomes after launching TAVR programs.
The heart’s main pumping chamber (left ventricle) and the main artery that supplies oxygen-rich blood to the body (the aorta) are separated from one another by the aortic valve. Calcification of the aortic valve — the most common form of aortic stenosis (AS) and also the second most frequent cause of cardiac surgery — typically occurs in older patients (ages ≥70). Smoking, hypertension, diabetes, LDL cholesterol, and elevated C-reactive protein are among the risk factors associated with AS. About 80% of AS cases in adults in the U.S. and Europe involve calcification of normal trileaflet valves. The disease spectrum ranges from aortic sclerosis (defined as leaflet thickening without obstruction) to severe AS.
In addition to aortic valve regurgitation, AS usually necessitates aortic valve repair or replacement. Congenital heart disease, thickening of the valve’s closure flaps (cusps), or post-inflammatory change (for example, seen in association with rheumatic heart disease) are some of the factors that may cause the aortic valve to become obstructed, which makes it harder for the heart to pump blood into the aorta. Medication alone will not suffice for this mechanical problem, and surgery is eventually needed to mitigate against the risk of heart failure, heart attack, stroke, and premature death due to a sudden heart attack.
It is important to better understand outcomes related to the major, evolving surgical procedures used to treat valvular heart disease — SAVR and TAVR — as these findings will guide the optimization of patient care. During SAVR, an incision is made in the chest to gain access to the heart. For several decades, SAVR has been the standard of care for patients with severe AS. In contrast, TAVR — a minimally invasive, catheter-based procedure — has evolved immensely since it was first approved by the FDA in 2011 for high-risk and inoperable patients with symptomatic AS.
A joint report of the American Association for Thoracic Surgery, the American College of Cardiology, the Society for Cardiovascular Angiography and Interventions, and the Society of Thoracic Surgeons recommends that sites need to reach a SAVR threshold, and that TAVR sites must achieve an acceptable SAVR metric.
Current debate centers on the need to ensure that patient access to AS treatment is balanced against a need to ensure that the centers are performing well enough and are doing enough procedures to continue offering TAVR. Resolution of this debate is important, as the Centers for Medicare & Medicaid Services (CMS) will be releasing a new national coverage determination for TAVR in 2019.
Study Synopsis and Perspective:
Between January 2010 and September 2015, CMS data from 519 centers — which together performed more than 50,000 TAVRs during the study period — were collected. Study participants included U.S. patients ages ≥65. Using hospital risk-adjusted 30-day mortality for SAVR in the pre-TAVR period as a proxy for SAVR quality, investigators found slightly higher 30-day TAVR mortality when those programs were established at what had been lower-quality SAVR centers (P<0.001 for trend):
- Quartile 1: 4.6% (reference)
- Quartile 2: 5.0% (adjusted OR 1.02, 95% CI 0.87-1.21)
- Quartile 3: 5.1% (adjusted OR 1.13, 95% CI 1.02-1.26)
- Quartile 4: 5.6% (adjusted OR 1.23, 95% CI 1.07-1.40)
The same pattern was observed for 1-year TAVR mortality, with a range from 17.0% at the best SAVR centers to 18.6% at the worst, reported Robert Yeh, MD, of Beth Israel Deaconess Medical Center in Boston, and colleagues.
“In this study, we demonstrated that hospitals with higher risk-adjusted mortality after SAVR prior to TAVR approval did indeed have higher short-term and long-term mortality for TAVR during the early phase of TAVR introduction and growth in the United States,” the investigators noted. “This association between baseline SAVR quality and subsequent TAVR outcomes persisted after adjustment for hospital TAVR volume, which has a powerful association with TAVR outcomes, as well as patient comorbidities and other hospital characteristics.”
Yeh’s group acknowledged that their reliance on an administrative database left room for residual confounding, inaccuracies due to coding errors, and inadequate risk adjustment due to the lack of important patient characteristics. Another limitation includes the lack of inclusion of variables that increases surgical risk, such as frailty and liver disease.
JAMA Cardiology, Dec. 5, 2018, DOI:10.1001/jamacardio.2018.4051
Study Highlights: Explanation of Findings
Following the introduction of TAVR programs, hospitals with higher SAVR-related fatalities also had higher short- and long-term TAVR-related deaths. A hospital’s performance with new structural heart disease programs can therefore be linked to the quality of cardiac surgical care. A sensitivity analysis excluding hospitals that performed fewer than 10 TAVR procedures did not change the overall findings of the study, although it would have been more rigorous perhaps to exclude up to the first 50 cases from each hospital, wrote John Carroll, MD, of the University of Colorado School of Medicine in Aurora, in an accompanying commentary.
Another study recently showed that hospitals keeping up both their SAVR and TAVR volumes had the best 30-day survival rates TAVR.
“For the CMS, it is a careful balancing act of quality and access in determining TAVR site and clinician requirements. It is unclear if using the results of this study would reduce the number of sites able to offer TAVR,” Carroll stated.
Restricting TAVR sites would make it hard for populations with known healthcare disparities to access this less-invasive procedure. If they do end up at worse TAVR programs, “their outcomes may be adversely affected by social determinants that have nothing to do with the skills and experience of the local heart team,” Carroll suggested.
In the study, patients undergoing transapical access in particular benefited from going to the highest-quality surgical centers.
That the best SAVR centers produced better TAVR results could be by virtue of better patient selection, better operating theaters, and higher-quality cardiac surgical care units, Yeh and colleagues suggested.
The learning curve should not be forgotten as a factor of valve replacement outcomes, Carroll noted. “This is an important consideration for TAVR, because its dispersion in the United States to hundreds of new and inexperienced sites occurred during the period of data collection used in this study.” This could be particularly relevant for populations with known healthcare disparities in the U.S. to accessing TAVR and SAVR.
Original story on MedPage Today by Nicole Lou
Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner