Modeled outcome-based spoke-and-hub paradigm of TAVI care associated with improved national outcomes compared to a simulated volume threshold

1. In this cohort study, among 112 717 participants in the Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry, transitioning care to the best outcome site in a hospital referral region resulted in an estimated 1261 fewer adverse outcomes.

2. The median driving time from the original site to the best site was 22 minutes and 23 minutes in higher-volume and best-outcome sites, respectively.

Evidence Rating Level: 2 (Good)

Study Rundown: In the past decade, transcatheter aortic valve implantation (TAVI) has rapidly become a common therapeutic choice for patients with severe, symptomatic aortic stenosis. Despite the technological maturity of TAVI, there is known hospital-level variation in outcomes consistent with differential quality of care. This study aimed to model the association of volume thresholds vs spoke-and-hub implementation of outcome thresholds with TAVI outcomes and geographic access. Outcomes of patients undergoing TAVIs from July 2020 to March 2022 were modeled as though patients had been treated at (1) the nearest higher volume (≥50 TAVIs per year) or (2) the best outcome site within the hospital referral region. The primary outcome was the absolute difference in events between the adjusted observed and modeled 30-day composite of death, stroke, major bleeding, stage III acute kidney injury, and paravalvular leak. A total of 166 248 patients were included, of which 158 025 (95%) were treated in higher-volume sites, and 75 088 (45%) were treated in best-outcome sites. In terms of volume threshold, there was no significant reduction in adverse events, and the median driving time from the existing site to the alternate site was 22 minutes. However, transitioning care to the best outcome site in a hospital referral region resulted in approximately 1261 fewer adverse outcomes, and driving time from the original site to the best site was 23 minutes. By assessing 30-day outcomes, this study incentivized sites to build care pathways with referring healthcare providers and the healthcare system to further quality of care. However, this study was limited in that the model assumes the outcome achieved at the modeled alternate site remained constant. Overall, this study found that an outcome-based spoke-and-hub paradigm of TAVI care improved outcomes to a greater extent when compared to a simulated volume threshold.

Click to read the study in JAMA Cardiology

Relevant Reading: Hospital variation in 30-day readmissions following transcatheter aortic valve replacement

In-Depth [prospective cohort]: This study modeled the association of volume thresholds vs spoke-and-hub implementation of outcome thresholds with TAVI outcomes and geographic access. A total of 166 248 patients with a mean (SD) age of 79.5 (8.6) years; 74 699 (47.3%) female, were included in this study. Patients were enrolled in the US Society of Thoracic Surgeons/American College of Cardiology Transcatheter Valve Therapy registry. Site volumes were determined from a baseline cohort of patients undergoing TAVI between 2017 and 2020. Outcomes of patients undergoing TAVIs from July 2020 to March 2022 were modeled as though patients had been treated at the nearest higher volume or best outcome site within the hospital referral region. A total of 158 025 (95%) participants were treated in higher-volume sites (≥50 TAVIs per year), and 75 088 (45%) participants were treated in best-outcome sites. No significant reduction in estimated adverse events was found when modeling a volume threshold (-34; 95% CI, -75 to 8), and the median (IQR) driving time was 22 (15-66) minutes. However, when transitioning care to the best outcome site in a hospital referral region, there were approximately 1261 fewer adverse outcomes (95% CI, 1013-1500), and the median (IQR) driving time from the original site to the best site was 23 (15-41) minutes.

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