Variation in mechanical circulatory support use for acute myocardial infarction cardiogenic shock

Clinical Snapshot

Key Findings

• P Value: p=0.032 for PCI volume difference, p=0.023 for safety net status

• Effect Size: 13% of IABP variation and 18% of PVAD variation attributable to hospital-level factors

• Primary Outcome: Interhospital variation in mechanical circulatory support use

• Nnt Or Sensitivity: High-PVAD hospitals: 48% lower ECMO escalation risk (OR 0.52, 95% CI 0.29-0.95)

• Confidence Interval: IABP: 11-14%, PVAD: 15-20%

Clinical Application

Requires institutional protocols and staff training for mechanical circulatory support deployment Relevant to Australian tertiary cardiac centres, though device availability and funding through PBS/state health systems may differ from US practice patterns Adult patients with AMI cardiogenic shock in tertiary centres with interventional cardiology services

Abstract

BACKGROUND: Cardiogenic shock (CS) is a leading cause of mortality following acute myocardial infarction (AMI). Some patients may require intra-aortic balloon pump (IABP) or percutaneous ventricular assist device (PVAD) placement; however, there is a paucity of standardised algorithms to guide the deployment of each device. The present study evaluated interhospital variation in the use of IABP and PVAD for AMI CS and identified institutional factors associated with hospital-level device preference. METHODS: All non-elective adult hospitalisations entailing AMI and CS were identified within the 2019 Nationwide Readmissions Database. Patients were grouped into IABP, PVAD and non-mechanical circulatory support cohorts. The primary aim was to quantify the degree of interhospital variation in the use of IABP and PVAD. Escalation to extracorporeal membrane oxygenation (ECMO), left ventricular assist device (LVAD) implantation, length of stay and hospitalisation costs were secondarily assessed. Hospital factors, such as percutaneous coronary intervention (PCI) volume and safety net status, were also analysed. RESULTS: Among 53 903 patients, 23.4% received IABP, and 12.5% received PVAD. After adjustment for patient factors, approximately 13% (11-14%) of variation in IABP use and 18% (15-20%) of PVAD use were attributable to centre-level differences. High-PVAD hospitals had higher annual PCI volume (257 (185-369) vs 204 (148-276) cases/year, p=0.032) and were more commonly safety net institutions (27.4% vs 11.3%, p=0.023), compared to high-IABP hospitals. Patients treated at high-IABP and high-PVAD hospitals faced similar length of stay (β -0.16, 95% CI -1.82 to 1.49) and costs (β -$3500, 95% CI -16 600 to 9600). Those at high-PVAD hospitals had lower adjusted risk of escalation to ECMO (0.52, 95% CI 0.29 to 0.95) and LVAD implantation (0.28, 95% CI 0.08 to 0.94). CONCLUSIONS: The present study identified wide interhospital variation in the use of IABP and PVAD for AMI CS. Although the likelihood of escalation to ECMO or LVAD differed between hospital types, resource utilisation was similar.

References

1. 1.Verma, A., Chervu, N. L., Kim, J. J., Mallick, S., Ziaeian, B., & Benharash, P. (2024). Variation in mechanical circulatory support use for acute myocardial infarction cardiogenic shock. Heart. https://doi.org/10.1136/heartjnl-2024-325413