Recent updates from the Centers for Medicare & Medicaid Services (CMS) maintain the volume requirements of the transcatheter aortic-valve replacement (TAVR) programs to qualify for reimbursement. In corroborate with the CMS updates, the latest data from the Society of Thoracic Surgeons/American College of Cardiology (STS/ACC) Transcatheter Valve Therapy (TVT) Registry by Dr. Sreekanth Vemulapalli et al., published in the New England Journal of Medicine, revealed lower 30-day mortality at hospitals with a high procedural volume.
TAVR was introduced in 2011 in the US and according to the CMS policy, programs are mandated to perform a minimum of 20 TAVR procedures in the prior year or at least 40 in the prior 2 years to qualify for reimbursement. Prior to the newly published analysis from the STS/ACC TVT Registry, there were no data regarding the relationship of TAVR volume and the patient outcomes.
The primary outcome was the 30-day risk-adjusted mortality after transfemoral TAVR. Secondary outcomes included a 30-day composite complication outcome such as stroke, moderate or severe paravalvular leak, major vascular access-site complications, major or life-threatening or disabling bleeding, or acute kidney injury) and outcomes for each component of the composite outcome.
The analysis included more than 100,000 TAVR transfemoral and nontransfemoral procedures from 2015 to 2017 in the United States. The median annualized hospital procedural volume was 54 and operator procedural volume was 27. The majority of the hospitals with low procedural volume were rural. Of note, most patients in the lowest-volume hospitals were black or Hispanic.
For both transfemoral and nontransfemoral procedures, annualized hospital and operator procedural volumes were inversely associated with 30-day mortality. For transfemoral procedures, the primary outcome of adjusted 30-day mortality was higher at hospitals with the lowest-volume quartile (3.19%) compared to the highest-volume quartile (2.66%; OR=1.21; P=0.02). The inverse volume-mortality relationship was also observed for nontransfemoral procedures, with a 30-day mortality risk of 10.13% at the lowest quartile vs. 6.40% at the highest quartile (OR=1.65).
Sensitivity analyses were performed to account for the operator “learning curve” and the hospital “start-up”. The inverse relationship between procedural volume and mortality was unchanged after excluding procedures performed within the first 6 and 12 months of the first TAVR procedure at the hospital. Hospitals in the lowest-volume quartile remained to have a higher 30-day mortality than hospitals in highest-volume quartile (3.10% vs. 2.61%; OR=1.19).
“A volume–mortality association persists in the United States for transfemoral TAVR, as well as TAVR using nontransfemoral approaches, despite improved patient selection, technology, and techniques as well as expansion of indications to intermediate-risk patients.” – Dr. Sreekanth Vemulapalli, M.D.
The hospitals with high procedural volume were larger and performed more nontransfemoral procedures. Therefore, more expertise of the operators and the access to other services to treat concurrent conditions might explain the lower mortality. Although it remains unclear whether lowering the volume threshold would improve access to TAVR or affect mortality, these results support the use of procedural volume as a quality metric for TAVR programs.