Impact of volume and intensive cardiac care unit availability on mortality of patients with acute myocardial infarction- related cardiogenic shock treated at revascularization capable centers

Abstract

Abstract Background Cardiogenic shock (CS) is associated with a high mortality. The purpose of this study was to assess the impact of hospital structure-related variables as volume of CS cases and availability of intensive cardiac care unit (ICCU) on hospital mortality in patients with ACS-related CS treated at high complexity revascularization capable centers (RCC) from a large nationwide registry. Methods This was a retrospective observational study including consecutive patients with main or secondary diagnosis of CS (ICD-10 code: R57.0) and ST elevation myocardial infarction (STEMI). Patients discharged from Spanish National Healthcare System (SNHS) RCC were included (2016-2020). Transfers between hospitals were assigned to reference hospital. Exclusion criteria were <35 years, voluntary discharges or stays ≤ 1 day. Low- and high-volumen hospitals were classified by k-means clustering with 79 cases as the cut-off point selected. The association between the volume of CS cases attended by each center, availability of ICCU and heart transplantation (HT) programs and in-hospital mortality was assessed by multilevel logistic regression models. Results The study population consisted of 3,065 CS-STEMI episodes, of whom 1,759 (57.4%) occurred in 26 centers with ICCU. Figure 1 shows the profile, management and complications of patients according to ICCU availability. A significantly greater number of circulatory support procedures a higher stroke incidence and a longer hospital stay were observed at hospitals with ICCU. A total of 17/44 hospitals (38.6%) were high-volume centers and 19/44 (43%) centers had HT programs available. Treatment at HT centers was not significantly associated with a lower mortality (p=0.264). Both high volume of cases and ICCU showed a non-significant trend to an association with lower mortality in the adjustment model (OR: 0.86 and 0.88, respectively). The interaction between both variables was significantly protective (OR 0.71; p=0.025). After propensity score matching mortality was lower in high volume hospitals with ICCU [OR = 0.79; p=0.0075] (figure 2). Conclusions Most CS STEMI patients from this series were attended at RCC with high volume of cases and ICCU available. The combination of high-volume and ICCU availability showed the lowest adjusted in-hospital mortality. These data should be taken into account when designing regional networks for CS management.Figure 1Figure 2