Conduits in coronary artery bypass grafting surgery
Saphenous vein, radial and internal thoracic arteriesav
Mats Dreifaldt
Akademisk avhandling
Avhandling för medicine doktorsexamen i Medicinsk vetenskap med inriktning mot kirurgi,
som kommer att försvaras offentligt fredagen den 11 oktober 2013 kl. 13.15, Wilandersalen, Universitetssjukhuset Örebro Opponent: Professor Anders Jeppsson, Sahlgrenska
universitetssjukhuset, Göteborg
Örebro universitet
Institutionen för hälsovetenskap och medicin 701 82 ÖREBRO
Abstract
Mats Dreifaldt (2013): Conduits in coronary artery bypass grafting surgery: Saphenous vein, radial and internal thoracic arteries. Örebro Studies in Medicine 93.
A novel technique for saphenous vein (SV) graft harvesting, the No-touch technique (NT), has been developed at the Dept. of Cardiovascular sur-gery, Örebro University hospital. With NT the SV is harvested with a pedicle of surrounding tissue. This avoids graft spasm and eliminates the need for distension. The surrounding tissue acts as a structural support and is a rich source of vaso-dilating agents. A randomized controlled trial (RCT) has shown a significantly higher patency rate for NT SV grafts compared to SV grafts harvested with conventional technique (CT). This thesis evaluates some of the properties of the surrounding tissue and com-pares patency rates between NT SV and radial artery (RA) grafts and patency rates for internal thoracic artery (ITA) grafts harvested with and without surrounding tissue. Paper I investigated vasa vasorum (VV) in SV grafts and showed that the NT preserves an intact VV whereas CT does not. This could be one of the mechanisms underlying the improved paten-cy for NT SV grafts. Paper II evaluated VV and associated nitric oxide (NO) in SV and arterial grafts. SV grafts showed a higher number and larger VV, which correlated with NO production, compared to arterial grafts. NT SV grafts showed higher activity for e-NOS compared to CT SV grafts. Paper III is a RCT comparing patency rates between NT SV and RA grafts, three years after surgery, showing a significantly higher patency rate for NT SV grafts. Paper IV is a RCT comparing patency rates for ITA graft harvested with and without surrounding tissue and did not show any difference between graft preparations. In conclusion, the NT for SV graft harvesting preserves an intact vasa vasorum and associat-ed NO production. NT SV grafts show a higher patency rate than RA grafts. Harvesting of ITA with or without surrounding tissue does not affect patency rate.
Keywords: Cardiac surgery, Coronary artery bypass, Saphenous vein, Radial artery, Internal thoracic artery, Vasa vasorum, Nitric oxide, Graft patency. Mats Dreifaldt, Institutionen för hälsovetenskap och medicin, Örebro universitet, SE-701 82, Örebro, Sweden, mats.dreifaldt@orebroll.se
