Association between inflammatory biomarkers and 30-day mortality in patients with acute myocardial infarction complicated by cardiogenic shock

Type of funding sources: Public hospital(s). Main funding source(s): Hjertecentrets Forskningsudvalg, Rigshospitalet

Cardiogenic shock often induces an inflammatory response, but the prognostic importance of this is not well studied.

The present study investigates whether the inflammatory response as reflected in routine blood samples taken during admission is associated with 30-day mortality in patients with cardiogenic shock due to acute myocardial infarction (AMICS). We assessed patients surviving 2 days, since a full CRP-response may take more than 48 hours to develop.

Consecutive patients (N=1716) with a validated diagnosis of AMICS admitted to one of two tertiary heart centres covering a base population of approximately 4 million in the period from 2010 to 2017 were included. The median values of total leucocyte count (WBC) and C-reactive protein (CRP) corresponded well to optimum thresholds found using ROC analysis and were used as cut-off for stratification.

A total of 1114 (1122) of the 1716 patients were alive and had WBC (CRP) measured at day 3.

Median WBC was 12.6 x 109/L. Median CRP was 146 mg/L.

Patients with an elevated leucocyte response were significantly older (66 vs 64 yrs, P<.001), had a higher prevalence of diabetes mellitus (18% vs 13%) and were admitted with lower left ventricular ejection fraction (LVEF) (P<.001). Less had suffered out-of-hospital cardiac arrest (44% vs 58%, P<.001) or underwent mechanical ventilation during admission (84% vs 91%, P<.001).

Patients with an elevated CRP had higher Body Mass Indexes (BMI 27 vs 26, P=.03) and were admitted with higher lactates (6.4 vs 5.7 mmol/L, P=.01) and a lower EF (P=.05), while more underwent mechanical ventilation during admission (92% vs 82%, P<.001).

Elevated WBC among patients alive at day 3 was associated with a significantly higher 30-day mortality rate of 43% vs 30%, Plogrank<.001. Patients with an elevated CRP had a mortality rate of 42% vs 29%, Plogrank<.001. (fig. 1,2)

In a multivariable model for each biomarker, adjusting for factors associated with mortality in AMICS, including age, sex, diabetes, stroke, out-of-hospital cardiac arrest, arterial lactate, LVEF and mechanical ventilation, an elevated inflammatory response remained significantly associated with mortality. (HR(WBC↑) = 1.63 [1.29;2.06], P<.001. HR(CRP↑) = 1.51 [1.21;1.90], P<.001).

Leucocyte and CRP response at day 3 of admission are associated with increased mortality in AMICS.