Pathophysiologic Vasodilation in Cardiogenic Shock and Its Impact on Mortality.

BACKGROUND

Cardiogenic shock (CS) mortality remains near 40%. In addition to inadequate cardiac output, patients with severe CS may exhibit vasodilation. We aimed to examine the prevalence and consequences of vasodilation in CS.

METHODS

We analyzed all patients hospitalized at a CS referral center who were diagnosed with CS stages B to E and did not have concurrent sepsis or recent cardiac surgery. Vasodilation was defined by lower systemic vascular resistance (SVR), higher norepinephrine equivalent dose, or a blunted SVR response to pressors. Threshold SVR values were determined by their relation to 14-day mortality in spline models. The primary outcome was death within 14 days of CS onset in multivariable-adjusted Cox models.

RESULTS

This study included 713 patients with a mean age of 60 years and 27% females; 14-day mortality was 28%, and 38% were vasodilated. The median SVR was 1308 dynes•s•cm (interquartile range, 870-1652), median norepinephrine equivalent was 0.11 µg/kg per minute (interquartile range, 0-0.2), and 28% had a blunted pressor response. Each 100-dynes•s•cm decrease in SVR below 800 was associated with 20% higher mortality (adjusted hazard ratio, 1.23; =0.004). Each 0.1-µg/kg per minute increase in norepinephrine equivalent dose was associated with 15% higher mortality (adjusted hazard ratio, 1.12; <0.001). A blunted pressor response was associated with a nearly 2-fold mortality increase (adjusted hazard ratio, 1.74; =0.003).

CONCLUSIONS

Pathophysiologic vasodilation is prevalent in CS and independently associated with an increased risk of death. CS vasodilation can be identified by SVR <800 dynes•s•cm, high doses of pressors, or a blunted SVR response to pressors. Additional studies exploring mechanisms and treatments for CS vasodilation are needed.