Transcatheter aortic valve replacement (TAVR) received US regulatory approval for treatment of severe symptomatic aortic stenosis (AS) in November 2011. After subsequent approvals for expanded indications, it is now performed throughout Michigan but the distribution of these providers and their impact on access is uncertain. As the number of providers and utilization for TAVR grows, how procedural volume is distributed among providers may significantly impact patient outcomes.Methods
We determined geographic access to TAVR in Michigan as of October 2014, and compared it to access of other invasive cardiac services; namely, percutaneous coronary intervention (PCI), non-transplant cardiac surgery, and cardiac transplant surgery. A geographic information systems analysis was performed using recent U.S. Census Survey data and statewide inpatient data to construct maps of service areas around hospitals providing TAVR, PCI, non-transplant cardiac surgery, and cardiac transplant surgery. Service areas ranging across multiple driving distances were included in the analysis. Geographic access was calculated as percentage of the population living within the hospital service areas providing invasive cardiac services.Results
In October 2014, 15 hospitals provide TAVR in Michigan. For TAVR sites, the mean number of beds, annual discharges, and annual patient days are 571, 28,946, and 140,859, respectively. Compared to hospitals not offering TAVR, TAVR facilities were more likely to be non-profit (86.7% vs 71.0%), a teaching hospital (93.3% vs 87.1%), and rural (12.1% vs 6.5%). Of the 9,883,640 persons in Michigan, 4,492,941 (45.5%) live within 10 miles, 7,856,455 (79.5%) live within 30 miles, and 9,004,943 (91.1%) live within 50 miles driving distance of TAVR sites. These proportions compare favorably with hospitals providing PCI (8,857,148 [89.6%] living within 30 miles) and non-transplant cardiac surgery (8,814,143 [89.2%] living within 30 miles) as opposed to cardiac transplant surgery (5,481,122 [55.5%] living within 30 miles). For Michigan patients who underwent surgical valve replacement (SAVR) in 2010–2011, the median driving distance to a TAVR site was under 15 miles and under 10 miles to a hospital providing non-transplant cardiac surgery.Conclusions
Nearly 4 of 5 Michigan residents lived within 30 miles of TAVR services early after its approval, suggesting its wide availability despite initial regulations on its use. These findings may encourage growth in TAVR utilization and limit the development of expertise as procedural volume is distributed among more providers. Given procedural volume tends to relate positively with outcomes, increased access to TAVR may have negative effects on patient outcomes.