Background: After successful cardiopulmonary resuscitation (CPR) microaxial percutaneous left ventricular assist devices (pLVAD) were used to support the left ventricular function in selected patients with the aim to achieve myocardial recovery. Thereby, cardiac arrest is frequently differentiated into in-hospital cardiac arrest (IHCA) and out-of-hospital cardiac arrest (OHCA). The aim of this study was to compare hemodynamic parameters and outcome for IHCA and OHCA patients who received a microaxial pLVAD.

Methods: The Dresden Impella Registry is an ongoing registry including more than 650 patients since 2014. Among, a total of 132 received an Impella CP^® after IHCA and 85 after OHCA. After propensity score matching using a logistic regression model for adjustment of age, duration of CPR, sex, initial norepinephrine dosage, and initial serum lactate (nearest neighbor matching) the IHCA cohort included 66 patients and the OHCA cohort 31 patients. All-cause mortality at 30 days as well as clinical, laboratory and hemodynamic parameters were compared between both cohorts.

Results: The propensity score matched cohorts showed well balanced baseline characteristics (Table 1). At time of admission, IHCA patients were 75.2 ±0.9 years old, OHCA patients 73.2 ±1.2 years (p=0.109). In the IHCA cohort 19.7% were female and 29.0% in the OHCA cohort, respectively (p=0.306). The CPR was performed for 25.6±3.6 min among the IHCA patients and for 27.9±3.8 min in the OHCA cohort (p=0.207). The initial norepinephrine (NE) dosage (IHCA vs. OHCA 0.71±0.15 µg/kg/min vs. 0.53±0.08 µg/kg/min; p=0.827) and the initial serum lactate (IHCA vs. OHCA 9.5±0.6 mM vs. 8.4±0.6 mM; p=0.742) were high in both cohorts without any significant difference.

The all-cause mortality showed no difference at 30 days (IHCA vs. OHCA 71.2±5.6% vs. 77.4±7.5%, p=0.782, Figure 1). The comparison of mean arterial pressure, NE dosage and serum lactate showed no differences in course. The left ventricular ejection fraction did not differ between both cohorts (IHCA vs. OHCA 27.9%±1.9% vs. 23.2±2.1%, p=0.191). Furthermore, there was no difference in requirement of hemodialysis and occurrence of SIRS, or sepsis (Table 1). The duration of left ventricular unloading was 41.9±5.8 h among IHCA patients and 38.5±6.1 h among OHCA patients (p=0.618).

Conclusion: Thirty-day all-cause mortality did not differ between IHCA and OHCA patients receiving LV-unloading with a pLVAD. Furthermore, no differences were found for hemodynamic and clinical parameters between groups challenging the expressiveness of the widely performed categorization in IHCA and OHCA.