Abstract 17433: Improved Outcomes in Septic Shock With Pre-hospitalization Use of Angiotensin-converting Enzyme Inhibitors (ACEI) and Angiotensin Receptor Blockers (ARB)

Abstract

Background: The neurohormonal effects of angiotensin-converting enzyme inhibitors (ACEI) and angiotensin receptor blockers (ARB) are well recognized. Recent molecular studies have also demonstrated novel immune-modulating properties of ACEI/ARB through reduction of pro-inflammatory cytokines. In a recent study, obese trauma patients on pre-injury ACEI/ARB had reduced multi-organ failure scores and improved T cell function and monocyte maturation as compared to those not on ACEI/ARB. We sought to determine whether pre-hospital use of ACEI/ARB conferred improvements in outcomes in patients with septic shock (SS). Methods: We evaluated 248 patients admitted to the ICU with SS from January 2011 to April 2013. Comprehensive baseline demographic, clinical and echocardiographic data was obtained at time of ICU admission. We identified 90 patients on ACEI/ARB prior to ICU admission. Chi-square and t-tests were used to assess for differences in clinical parameters and outcomes in patients who were on ACE/ARB prior to ICU admission (ACE/ARB group) versus those not on ACEI/ARB prior to ICU admission (non-ACEI/ARB group). Results: Patients in the ACE/ARB group (36%) had significantly lower heart rate (95.8 bpm vs 102.3 bpm, p<0.05), higher MAP (80 mmHg vs 74 mmHg, p<0.05), higher serum potassium level (4.3 mEq/L vs 4.0 mEq/L, p<0.05), and less urine output (522cc vs 708cc per initial 24 hours, p<0.05) with a non-significant trend towards lower respiratory rate, WBC count, lactate level and APACHE 2 score. The ACEI/ARB group had higher left ventricular systolic diameter (1.26 cm vs 1.17 cm, p<0.05) and left ventricular posterior wall diameter (1.18 cm vs 1.07 cm, p<0.05); however, there were no other statistically significant echocardiographic differences between both groups. In-hospital and 90-day mortality was significantly less in the ACE/ARB group compared to the non-ACE/ARB group (20% vs 31.7%, p <0.05) and (25.6% vs 38%, p <0.05), respectively. Conclusion: ACEI/ARB use prior to ICU admission is associated with improved outcomes in SS patients, not explained by laboratory or echocardiographic differences. This provides further support for the possible immunomodulating benefits of ACEI/ARBs; however, more studies are needed to confirm these findings.