PURPOSE:While transfusion of PRBC has been associated with atrial fibrillation (AF) in cardiac surgical patients, no data exists on such a relationship in patients with acute MI (AMI). We chose to evaluate whether PRBC transfusion increases the risk of AF, Ventricular Tachycardia (VT) and other arrhythmias and conduction abnormalities in patients with AMI.
METHODS:Retrospective study on patients with AMI admitted to a Critical Care area and entered in the Project Impact database from August 2003-December 2007. We included only patients with AMI and no prior history of AF. Primary outcome measures were new onset cardiac arrhythmias or conduction disturbances; secondary endpoints were length of stay (LOS) and in-hospital mortality. Continuous variables were analyzed by the Mann-Whitney u-test, categorical variables by Fisher exact-test.
RESULTS:1599 patients were identified. 98 were excluded (prior history of AF/atrial flutter). Of those remaining, 147 received PRBC (Group T); 1354 did not (Group NT). Patients in Group T had significantly higher incidences of AF (4.8% vs. 1.3%, p= 0.008), Cardiac Arrest [CA](9.5% vs. 1.7%, p<0.001) and Heart Block [HB](3.4% vs. 0.1%, p<0.001), and a trend towards a higher incidence of VT(3.4% vs. 1.3%, p=0.056). Multivariate regression analysis adjusting for age, gender, race, and history of HTN, DM, CHF, COPD and CVA confirmed transfusion as an independent risk factor for “non-lethal” cardiac events (AF/HB, OR 3.7 [1.7–8.5], p<0.001), “lethal” events (VT/CA, OR 4.4 [2.3–8.4], p<0.001), and all cardiac events OR 3.8 [2.1–6.7], p<0.001. Transfused patients had significantly longer LOS (p<0.0001) and significantly higher mortality rates than non-transfused patients OR 4.3[2.5–6.8], p<0.001.
CONCLUSION:PRBC transfusion is independently associated with an increased risk of new onset cardiac arrhythmias and conduction abnormalities in the setting of AMI, even after controlling for traditional risk factors.
CLINICAL IMPLICATIONS:No previous study has evaluated the association of PRBC transfusions and the occurrence of cardiac arrhythmias and conduction disturbances in the setting of AMI. The findings of our study lend further support to a more restrictive transfusion strategy in the setting of AMI.
DISCLOSURE:M. Kamran Athar, No Financial Disclosure Information; No Product/Research Disclosure Information