CardioSource WorldNews | News and data from studies drawing from the National Cardiovascular Data Registry (NCDR) abounded in Chicago this past April at ACC.16. Here are some of the interesting NCDR-related findings you may have missed at the meeting.

How Does TAVR Impact Readmissions? And Who’s Better at Referral?

Sreekanth Vemulapalli, MD, and colleagues from the Duke Clinical Research Institute (DCRI) used data from The Society of Thoracic Surgeons/ACC TVT Registry to analyze pre- and post-transcatheter aortic valve replacement (TAVR) hospitalizations in nearly 24,000 patients. In the year after TAVR, patients had fewer heart failure (HF) admissions (20.4% vs. 11.4%, respectively; p <0.001) and fewer any cause hospital admissions (61.7% vs. 51.7%, respectively; p <0.001). This translated to decreased Medicare costs for patients who remained alive 1-year post-TAVR.

The value of TAVR has been clearly established and is showing benefits in even moderate-risk patients with aortic stenosis (AS). Timeliness of referral for these patients is important, but until now there has been little information regarding referral patterns.

Cassandra Ramm, MSN, AGNP-C, of the University of North Carolina, was first-author of a poster evaluating nine large valve treatment centers participating in the ACC’s Championing Care for the Patient with Aortic Stenosis initiative. Among 454 patients referred for AS management, non-cardiologists did a better job, referring patients earlier in the disease course than cardiologists.

According to the valve center physicians, patients referred by cardiologists were more likely to have been referred “late” or “too late” (14% vs. 7%, p = 0.004), whereas non-cardiologists were more likely to refer “too early” (12% vs. 3%; p = 0.04).

Also, patients referred by cardiologists were more likely to have advanced heart failure (New York Heart Association functional class IV: 31% vs. 7%; p < 0.0001) and trended towards higher STS risk scores (p = 0.06) than those referred by non-cardiologists.

Cardiologists appeared to be good at explaining TAVR to their patients, because individuals they referred to the valve center were more likely to strongly prefer TAVR at the time of the initial consult than patients referred by non-cardiologists (47% vs. 31%; p = 0.003).

Aspirin Dosing After ACS

Practice guidelines in the U.S. and Europe currently recommend treatment with a P2Y₁₂ receptor antagonist for up to 1 year after myocardial infarction (MI). Just before the Chicago meeting, the ACC and AHA released a focused update on duration of dual antiplatelet therapy (DAPT) in patients with coronary artery disease (CAD).¹ The new document notes that aspirin therapy should almost always be continued indefinitely in patients with CAD.

The focused update to several guidelines (percutaneous coronary intervention [PCI], coronary artery bypass graft surgery, stable ischemic heart disease, ST-elevation and non-ST-elevation myocardial infarction, perioperative cardiovascular evaluation, and management of patients undergoing non-cardiac surgery) also underscored that lower daily doses of aspirin are associated with lower bleeding complications with comparable ischemic protection than higher doses of aspirin. The recommended daily dose of aspirin in patients treated with DAPT is 81 mg (range: 75 mg to 100 mg).

The focused update states “…it is reasonable to use ticagrelor in preference to clopidogrel for maintenance P2Y₁₂ inhibitor treatment,” but one issue with ticagrelor is that high-dose maintenance aspirin (>100 mg daily) actually reduces ticagrelor’s effectiveness. So, what’s the contemporary dosing of aspirin in patients treated with ticagrelor?

Sundeep Basra, MD, MPH of Baylor College of Medicine, Houston, presented an analysis of data from the ACTION–GWTG Registry. They evaluated for 21,262 patients treated for acute MI at 620 sites. The good news: overall, only 2.5% of patients were discharged on high-dose aspirin. It was more common to see patients discharged on high-dose aspirin if they were discharged on prasugrel (29.5%) or clopidogrel (28.2%) compared to ticagrelor (2.5%).

The bad news: there were significant regional and hospital-level variations in high-dose aspirin therapy at discharge, ranging from 1.6% in the northeast, 2.1% in the Midwest, 2.9% in the south and 3.4% in the west (p value <0.001). Site-level variability was dramatic, including numerous centers where high-dose aspirin at discharge was used for 10% to 50% of acute MI patients. (In one center, such use comprised about 100% of discharged MI patients.)

Thus, there is a high rate of adherence to FDA and guideline recommendation with respect to the use of low-dose aspirin at discharge in ACS patients treated with ticagrelor. However, significant regional and hospital variability exists representing opportunity for further improvement.

TAVR and the Volume-Outcome Relationship

The volume-outcome relationship for TAVR is both statistically significant and clinically important, and TAVR outcomes are shown to improve significantly with increased TAVR volume, according to results of another study presented as part of ACC.16.

The trial, conducted by John D. Carroll, MD, FACC, and colleagues, analyzed data from the Society of Thoracic Surgeons (STS)/ACC TVT Registry to examine the possible relationship between cumulative TAVR volume and in-hospital outcomes in clinical practice in the U.S. All U.S. hospitals submitting consecutive cases to the STS/ACC TVT Registry were evaluated. There were 370 hospitals in the between November 2011 and the third quarter of 2015.

Among 36,292 procedures, the unadjusted in-hospital mortality rate ranged from 0% to 25%. Vascular complications, bleeding complications, and stroke complication all decreased as TAVR volume increased.

The volume-outcome relationship is intertwined with the learning curve in TAVR. “The early period (‘learning curve’), at low site volumes, has the steepest relationship for some outcomes,” the authors stated. “The later period, after achieving modest volumes (> 100 cases), shows further improvement in outcomes.”

The authors stressed that although association does not prove causality, understanding the volume-outcome relationship is important. They write that the data may help inform whether there is an annual volume threshold associated with better outcomes, and posit that it may also aid in patient selection of TAVR centers. Additionally,

because the National Coverage Determination from the Centers for Medicaid and Medicare Services considers procedure volume as a future criterion for coverage, the results may help inform decisions regarding optimizing TAVR in the U.S. health care system.

References

1. Levine GN, Bates ER, Bittl JA, et al. J Am Coll Cardiol. 2016;doi:10.1016/j.jacc/2016.03.513

Read the full June issue of CardioSource WorldNews at ACC.org/CSWN

Keywords: CardioSource WorldNews, National Cardiovascular Data Registries, Academies and Institutes, Aortic Valve Stenosis, Coronary Artery Bypass, Coronary Artery Disease, Heart Failure, Hospitalization, Medicare, Myocardial Infarction, Percutaneous Coronary Intervention, Referral and Consultation, Registries, Surgeons, Ticlopidine, Transcatheter Aortic Valve Replacement

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