Abstract 3375: Renal Dysfunction Predicts Poor Outcome in Patients Undergoing Cardiac Resynchronization Therapy
Background: Cardiac resynchronization therapy (CRT) improves outcomes in selected patients with congestive heart failure (CHF). However, CHF is frequently associated with CRI yet the impact of CRI on outcomes of patients undergoing CRT is unknown.
Methods: To determine this, we examined the impact of renal dysfunction in all patients who underwent CRT at the Mayo Clinic between 1999 and 2005. Creatinine clearance (CCl) was estimated using the Cockgroft-Gault equation and renal dysfunction was defined as mild (CCl <60 ml/min) or severe (CrCl <30 ml/min). Differences in outcome according to the severity of CRI were compared by Kaplan Meier survival curves.
Results: A total of 513 patients (410 male, 80%, mean age 68 ± 12 years) who underwent CRT device implantation during the study period were included. Underlying heart disease was ischemic in 316 (62%) and non- ischemic in 197 (38%). Mean ejection fraction was 22% ± 8% and was not significantly different in patients with mild versus severe CRI (p=0.09). Initial implant was successful in all except 22 patients; procedure time was not different between the groups (p=0.18). At 2 years survival was 68% versus 40% in patients with mild and severe CRI, repectively, compared with 81% in patients without CRI (p<0.01).
Conclusions: CRI, even when mild, is associated with increased mortality in patients undergoing CRT and should be accounted for when weighing the potential benefit of CRT.