Correlation between Coronary Artery Bypass Graft Surgery and Hearing Threshold Changes

Introduction: Sensorineural hearing loss (SNHL) is a probable complication of coronary artery bypass graft (CABG) Surgery, that may be due to embolism, perfusion failure and consumption of ototoxic drugs. Since the incidence of SNHL after CABG is different according to the various reports, the present study was designed to study hearing threshold change after CABG surgery. Method: In this cross-sectional study, 65 patients candidated for CABG surgery were selected by convenient sampling. One week before and two weeks after the surgery, all patients were examined by E.N.T specialist, and underwent PTA and impedance test. Other information including history of previous diseases were collected too. Distribution and central indices were used for description of results and Wilcoxon test was used for comparison of pre- and post- operative hearing threshold. Results: Comparison of Pre -and Post - operative audiometry results showed no significant change in hearing for all frequencies and in both ears. Hearing threshold difference in the right ear at 4000HZ and in the left ear at 2000HZ was meaningful (P=0.027, P=0.004 respectively). Although hearing threshold differences at all frequencies and in both ears were greater in men rather than women, the meaningful difference was only for the frequency of 1000HZ in the right ear (P=0.03) and 4000HZ in the left ear (P=0.034). Conclusion: Although, hearing loss can occur after nonotologic surgeries, the incidence is very low and this can be due to the improvement in surgical and anesthesia techniques. Meanwhile, hearing threshold change in some frequencies may be sex-dependent.