Hospital volume-outcome relationship in Mechanical Thrombectomy for Acute Ischemic Stroke: A National Inpatient Sample Study

Sunday, March 30, 2025

3:18 PM – 3:27 PM CT

Location: Music City Center, 205 BC

Presenting Author(s)

Waseem Wahood, MD, MS

Resident
Jackson Memorial Hospital, University of Miami, United States

Author/Co-author(s)

KR

Kenan R. Rajjoub, MD

Research Fellow
Mayo Clinic, United States
WB

Waleed Brinjikji, MD

Associate Professor
Department of Radiology, Mayo Clinic, United States

Purpose: The certification requirement for hospitals to be considered stroke centers in the United States is greater than 15 cases of mechanical thrombectomy (MT) for acute ischemic stroke (AIS) annually for center and proceduralist. Few studies have evaluated the association between MT case-volume with clinical outcomes.

Materials and Methods:

National Inpatient Sample (NIS) was queried from 2013 to 2020 for admissions involving MT for AIS. Hospitals were divided into tertiles based on their volume of MT per year. Multivariable, Hierarchical logistic regression was utilized to assess risk factors of in-hospital mortality, discharge other than home (DOTH), and poor outcome, a surrogate for 90-day mRS >3. Negative binomial regression was utilized to assess factors of length of stay (LOS) of the two higher volume tertiles, to the first, lowest volume, tertile.

Results:

A total of 123,240 admissions were identified; 42,900 (34.8%)in the lowest tertile, 40,650 (33.0%) in the 2^nd tertile and 39,690 (32.2%) in the 3^rd and highest tertile. Those in the 2^nd tertile had similar odds of in-hospital mortality compared to the first tertile (OR: 0.91, p=0.073), while there were lower odds of in-hospital mortality when comparing the highest tertile to the lowest (OR: 0.86; p=0.008). Those in the 2^nd had similar odds of DOTH compared to the first tertile (OR: 1.07, p=0.56)), while those in the 3^rd tertile had lower odds of DOTH (OR: 0.84; p=0.001). Those in the 2^nd and 3^rd tertiles had similar odds of poor outcome compared to the first tertile (2^nd: 1.07, p=0.56; 3^rd: 0.88; p=0.41). Compared to the first tertile, those in the 3^rd tertiles were associated with lower average LOS by 4.8% (p< 0.001).

Conclusion: Higher hospital volumes for MT may be associated with lower odds of mortality and DOTH as well as lower average LOS. However, poor outcome was comparable among the three tertiles. Further research is needed to fully understand the relationship between hospital MT volume and patient outcomes.