Abstract 220: Longer Door to Balloon Time: Effect of Chronic Kidney Disease on Each Step Leading to PCI

Abstract

Purpose: Primary percutaneous coronary intervention (PCI) is a time-sensitive process. In high risk populations this time could be longer and affect the reperfusion results. The aim of this study was to examine the door-to-balloon time in patients with chronic kidney disease (CKD) and determine the influence of CKD at each step leading to PCI. Methods: We conducted a retrospective study of patients admitted at an academic medical center for suspicion of acute coronary syndrome from 2004 to 2011. ICD9 codes were used to identify patients with myocardial infarction (MI) and comorbidities. CKD was defined using an estimated glomerular filtration rate (GFR) <60 mL/min/1.73 m 2 . ST segment elevation (STEMI) status was ascertained at hospital admission. In our hospital, date-times of each step (diagnostic ECG, alert for potential MI) are monitored. Non-parametric tests were used to compare time intervals according to GFR. Because the door-to-balloon time is right skewed, we log transformed time and modeled it as gamma distributed using a generalized estimating equation (GEE) to examine its association with CKD, after adjusting for age, gender, race, hypertension, congestive heart failure, and diabetes. Results: Our study population included 712 patients with STEMI, of whom 138 (19.4%) had CKD (see table). Door-to-balloon time was longer in patients with GFR <30. Likewise diagnostic ECG-to-MI alert time was longer in patients with GFR <30 whereas MI alert-to-balloon time was not different between those with and without CKD. Results from the GEE showed that GFR<30 was an independent predictor of door-to-balloon time. Conclusion: Patients with severe CKD have a longer door-to-balloon time than patients without CKD. This difference seems to be due to a longer time-interval between the time the diagnostic ECG is made and the time the MI alert is called. This delay in initiating PCI could be related to the misleading ECG (left ventricular hypertrophy, electrolyte and conduction abnormalities) frequently found in patients with CKD.