PHRENIC-NERVE INJURY AFTER CORONARY-ARTERY BYPASS-GRAFTING - WILL IT GO AWAY

Background. Phrenic nerve injury after coronary artery bypass grafting resolves in most cases. The purpose of this study was to analyze the causes and effects of persistent phrenic nerve injury after coronary a rtery bypass grafting. Methods. From a registry of patients with chron ic obstructive pulmonary disease who underwent coronary artery bypass grafting, 64 patients were identified who experienced phrenic nerve in jury during their operation. Fifteen patients either died during follo w-up (n = 9) or were lost to follow-up (n = 6). At the last follow-up visit, all the patients underwent an ultrasound evaluation of the diap hragm and were divided into those who had persistent dysfunction (grou p I) and those who had normal function (group II). The groups were com pared for preoperative and operative risk factors, acute and midterm p ostoperative results, and quality of life at last follow-up. Results. There were 13 patients in group I and 36 in group II. There were no si gnificant differences in preoperative and operative risk factors betwe en the groups. The length of hospitalization was similar for both grou ps (9.2 +/- 4.5 versus 8.5 +/- 3.3 days, respectively; p = 0.77). More patients in group I required reintubation (23% versus 14%, respective ly; p = 0.04). The mean duration of follow-up was 32.7 +/- 9.2 months. At that time, both groups suffered a reduction of forced expiratory v olume in 1 second compared with preoperative values. Group I had a gre ater reduction in forced expiratory volume in 1 second (p = 0.05). The re were a total of 125 postoperative readmissions during the follow-up period, 36 in group I and 89 in group II. There were more admissions because of pulmonary problems in group I (85% versus 53%; p = 0.04). O f the 49 patients, 21 perceived a decline in quality of Life after ope ration. More patients in group I (46% versus 22%; p = 0.05) complained of this decrease. Conclusions. A significant number of patients who i ncur phrenic nerve injury after coronary artery bypass grafting have p ersistent phrenic nerve injury. Patients with persistent phrenic nerve injury have increased acute and midterm morbidity after operation, as well as reduced quality of life. (C) 1998 by The Society of Thoracic Surgeons.