Impacts of Hospital Volume and Patient-Hospital Distances on Outcomes of Older Adults Receiving Percutaneous Microaxial Ventricular Assist Devices for Cardiogenic Shock.

BACKGROUND

Percutaneous microaxial ventricular assist devices (pVADs) have the potential to reduce mortality of patients with cardiogenic shock (CS). However, the association between the distribution of pVAD-performing centers and outcomes of CS has not been explored.

METHODS

This observational study included Medicare fee-for-service beneficiaries aged 65 to 99 years treated with pVAD for CS from 2016 to 2020. It examined the associations between patient outcomes and 2 exposure variables: hospitals' procedure volumes of pVAD and patient-hospital distances (in quintiles [Qn]). We developed Cox proportional hazards regression for 180-day mortality and heart failure readmission rates, and multivariable logistic regression for in-hospital outcomes, adjusting for patient demographics, comorbidities, concomitant treatments, and hospital characteristics, including CS volume, teaching status, and the ability to perform extracorporeal membrane oxygenation.

RESULTS

A total of 6637 patients with CS underwent pVAD at 1041 hospitals, with the annualized hospital volume ranging widely from 0.3 to 55.6 cases/year. Patients treated at higher-volume centers experienced lower 180-day mortality compared with those treated at lower-volume centers (Qn1=reference; Qn2: adjusted hazard ratio [aHR], 0.88 [95% CI, 0.79-0.97]; Qn3: aHR, 0.88 [95% CI, 0.79-0.98]; Qn4: aHR, 0.88 [95% CI, 0.78-0.99]; Qn5: aHR, 0.84 [95% CI, 0.74-0.95]; for trend, 0.026), while we found no evidence that patient-hospital distances were associated with mortality (Qn1=reference; Qn2: aHR, 0.99 [95% CI, 0.89-1.09]; Qn3: aHR, 0.94 [95% CI, 0.85-1.04]; Qn4: aHR, 1.01 [95% CI, 0.92-1.11]; Qn5: aHR, 0.91 [95% CI, 0.82-1.01]; for trend, 0.160). We found no evidence that the hospital volume and patient-hospital distances were associated with in-hospital bleeding, intracranial hemorrhage, or renal replacement therapy initiation.

CONCLUSIONS

Hospital volume was more strongly associated with mortality than patient-hospital distances, suggesting that rational distribution of pVAD-performing centers while ensuring adequate procedure volumes may optimize patient mortality.