Sodium nitroprusside in heart failure-related and acute myocardial infarction-related cardiogenic shock: friend or foe?

Cardiogenic shock (CS) is a clinical syndrome associated with high morbidity and mortality, highly prevalent in the modern-era cardiac intensive care unit (CICU). Vasodilator therapy with intravenous sodium nitroprusside (SNP) has a strong physiological rationale and has been shown to be safe and effective in restoring left ventricular hemodynamics and improving outcomes in patients with advanced low-output heart failure.

To explore the relationship between SNP infusion and survival in patients admitted to the CICU and diagnosed with CS, according to the presenting CS phenotype.

We enrolled 725 consecutive patients admitted to the Altshock-2 registry (a multicentre prospective study including 12 Italian tertiary CICUs) from March 2020 to January 2024. Patients were grouped into heart failure-related CS (HF-CS) and acute myocardial infarction-related CS (AMI-CS) according to etiology at presentation. Patients with other etiologies of CS (e.g., pulmonary embolism, acute myocarditis, arrhythmic storm) were excluded. Survival analysis was performed with Cox regression. Survival was assessed at 180 days, as well as freedom from a composite outcome of death, LVAD implantation, or heart transplantation (HTx). The maximal dose of SNP and the duration of infusion were recorded. Continuous renal replacement therapy (CRRT) and temporary mechanical circulatory support (tMCS) use were also documented, as well as maximal vasoactive-inotropic score (VIS) values.

Among the 353 patients with AMI-CS (242 with data available) and 253 patients with HF-CS (175 with data available), 78% were male with a median age of 66.

Of the patients presenting with AMI-CS, 43 (17%) received an SNP infusion (median dose 0.5 µg/kg/min, median duration 72 hours, median baseline LVEF 25%); at univariable Cox analysis, there was no significant difference in 180-day survival (HR 0.82, 95% CI 0.52-1.30, p=0.40) between patients who received SNP and those who did not.

Among patients presenting with HF-CS, 75 (42%) received SNP infusion (median dose 0.6 µg/kg/min, median duration 160 hours, median LVEF 23%); at univariable Cox analysis, patients who received SNP showed lower mortality at 180 days (HR 0.59, 95% CI 0.38-0.90, p=0.016), as well as at multivariable Cox analysis after adjusting for CRRT, tMCS use, and VIS values (HR 0.63, 95% CI 0.41-0.98, p=0.041). However, at univariate Cox regression, there was no significant difference in 180-day freedom from death, LVAD, or HTx (HR 0.86, 95% CI 0.6-1.23, p=0.41) in patients who received SNP compared to those who did not.