The effects of internal thoracic artery preparation with intact pleura on respiratory function and patients' early outcomes.

Objective: Postoperative respiratory functions, arterial blood gases, blood loss and clinical outcome following coronary artery bypass surgery (CABG) were assessed in a prospective randomized single-blind (patient- blind) clinical study comparing two different techniques of internal thoracic artery (ITA) harvesting.

Methods: Fifty-four patients admitted for CABG were allocated into two groups according to 'random numbers' technique. In a Group 1 (n=26) ITA was prepared keeping the pleura intact and in a Group 2 (n=28) pleura was opened. Both groups were compared in terms of postoperative respiratory functions, arterial blood gases, bleeding and clinical outcomes using ANOVA for repeated measurements analysis.

Results: Analysis of spirometric and partial oxygen pressure data showed that postoperative reductions in forced expiratory volume (0.17+/-0.18 lt vs. 0.28+/-0.14 lt, p=0.016), forced vital capacity (0.18+/-0.19 lt vs. 0.28+/-0.13 lt, p=0.037) and arterial oxygen measurements (-0.03+/-0.22 mmHg vs. 0.15+/-0.4 mmHg, p=0.023) were less pronounced in patients of Group 1 as compared with patients of Group 2. The increase in intrapulmonary shunts (Qs/Qt ratio) after the operation was more pronounced in Group 2 patients than in Group 1 patients (p<0.01) and the mean values of Qs/Qt ratio 24 hours after the operation were higher in group 2 as compared to Group 1 patients(0.100+/-0.063 vs. 0.054+/-0.048, p=0.001). Radiological evaluation revealed that costophrenic angle obliteration after operation more often occurred in Group 2 (14/28 patients) than in Group 1 (0/26 patients) (p<0.0001). Cardiothoracic index increased significantly after operation only in group 2 patients (p=0.001). Postoperative blood loss within 24 hours was significantly lower in Group 1 compared to Group 2 (656+/-179 ml vs. 907+/-257 ml, p=0.001). There was no significant difference between groups in the ICU stay duration (p=0.186), whereas the hospital stay was significantly longer in group 2 patients than in Group 1 patients (8.8+/-2.0 days vs. 7.6+/-2.0 days, p=0.039).

Conclusion: According to our results, preserving pleural integrity has positive effects on the respiratory functions and patients' clinical outcomes following CABG operations.