Glycemic patterns and impact of early hyperglycaemia in patients with cardiogenic shock on mechanical circulatory support

Aims: Hyperglycaemia has been an established predictor of poor outcomes in critically ill patients. The aim of this study is to assess the pattern of early glycemic control in patients with cardiogenic shock (CS) on temporary mechanical circulatory support (MCS) and its impact on short-term outcomes.

Methods and results: All adult patients admitted to the Cleveland clinic cardiac intensive care unit (CICU) between 2015 and 2019 with CS necessitating MCS with intra-aortic balloon pump (IABP), Impella or venous arterial- extra corporeal membrane oxygenation (VA- ECMO) exclusively for CS were retrospectively analyzed. Blood glucose values were collected for the first 72 h from the time of MCS insertion. Patients were categorized into three groups [group 1 = mean blood glucose (MBG) < 140, group 2 = MBG between 140 and 180, and group 3 = MBG >180]. The primary outcome was 30-day all-cause mortality. A total of 393 patients with CS on temporary MCS [median age (Q1, Q3), 63 (54, 70), 42% females], were admitted to our CICU during the study period. Of these, 144 patients (37%) were on IABP, 121 patients (31%) were on Impella, and 128 (32%) were on VA-ECMO. Upon stratifying the patients into groups depending on MBG during the initial time period after MCS placement, 174 patients (44%) had MBG less than 140 mg/dL, 126 patients (32%) had MBG between 140 and 180 mg/dL whereas 93 (24%) patients had MBG > 180 mg/dL. Overall, patients on IABP had the best glycemic control during the early period whereas those on ECMO had the highest MBG during the initial timeframe. A comparison of 30-day mortality revealed that patients with MBG >180 mg/dL had worse outcomes compared to the other two groups (P = 0.005). Multivariable logistic regression revealed that hyperglycaemia was an independent predictor of poor outcomes in CS patients on MCS when undifferentiated by device type (aOR 2.27, 95% CI 1.19-4.42, P = 0.01). However, upon adjusting for the type of MCS device, this effect was no longer present.

Conclusion: A significant proportion of patients with CS on MCS manifest early hyperglycaemia regardless of diabetic status. The presence of early hyperglycaemia in these patients acted predominantly as a surrogate of the underlying shock severity and was associated with worse short-term outcomes. Future studies should assess whether strategies to optimize glycemic control in this high-risk cohort can independently improve clinical outcomes.