Influence of Type 2 Diabetes on Functional and Structural Properties of Coronary Artery Bypass Conduits

Influence of Type 2 Diabetes on Functional and Structural Properties of Coronary Artery Bypass Conduits Roberto Lorusso 1 , Samuele Pentiricci 1 , Riccardo Raddino 2 , Tiziano M. Scarabelli 2 , Claudia Zambelli 3 , Vincenzo Villanacci 3 , Anna Burattin 4 , Giuseppe Romanelli 4 , Salvatore Casari 5 , Roberto Scelsi 6 and Andrea Giustina 4 1 Cardiac Surgery Division, Civic Hospital, Brescia, Italy 2 Cardiology Division, Civic Hospital, Brescia, Italy 3 Pathology Division, Civic Hospital, Brescia, Italy 4 Internal Medicine (Endocrine Section) Division, Civic Hospital, Brescia, Italy 5 Infective Disease (Statistics Unit) Division, Civic Hospital, Brescia, Italy 6 Pathology Division, University of Pavia, Pavia, Italy Address correspondence and reprint requests to Roberto Lorusso, MD, PhD, IIa Divisione Cardiochirurgica, Ospedale Civile, Piazzale Spedali Civili 1, 25125 Brescia, Italy. E-mail: roberto_lorusso{at}iol.it Abstract Recent studies have reported a high incidence of postoperative unfavorable cardiac-related events in patients with diabetes who underwent coronary artery bypass grafting (CABG). Structural and functional characteristics of CABG conduits, which have been shown to play an important role in patient outcome after myocardial revascularization, have not been fully investigated in diabetic subjects. Therefore, we sought to determine the influence of adult-onset diabetes on vasoreactivity and morphological profile of venous and arterial grafts. Of the 160 consecutive patients enrolled in the study, 90 were diagnosed with type 2 diabetes and 70 did not have diabetes (control group). All patients underwent evaluation of glucose control before surgery. Tissue specimens were collected from left internal thoracic artery (LITA) and saphenous vein (SV) grafts harvested during elective CABG. Functional tests were performed to assess contractile and vasodilative responses of bypass conduits. Histological evaluation was carried out to examine vessel wall structure. Univariate and multivariate analyses were performed to correlate the preoperative factors related to the control of the endocrine disorder with histological findings. Patient medical history and demographics did not differ between the groups. Diabetic patients showed significant microalbuminuria and higher plasma levels of C-peptide and GHb as compared with nondiabetic subjects. Functional tests of the LITA segments revealed no difference between groups with regard to contractile and vasodilativ