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Published on: March 27, 2018
Influence of Diabetes on Long-Term Coronary Artery Bypass Graft Patency
Sajjad Raza1, Eugene H Blackstone2, Penny L Houghtaling3
1Department of Thoracic and Cardiovascular Surgery, Cleveland Clinic, Cleveland, Ohio.
Insights
Diabetes does not impact long-term bypass graft patency. Internal thoracic artery (ITA) grafts show excellent, stable patency in diabetic and non-diabetic patients, suggesting their maximized use in coronary artery bypass grafting (CABG).
Area of Science:
- Cardiovascular Surgery
- Diabetology
- Vascular Biology
Background:
- Coronary artery bypass grafting (CABG) is common, with nearly 50% of patients having diabetes.
- The impact of diabetes on long-term bypass graft patency remains incompletely understood.
- Diabetic patients often present with more severe coronary artery disease, raising concerns about graft outcomes.
Purpose of the Study:
- To investigate the influence of diabetes on the long-term patency of internal thoracic artery (ITA) and saphenous vein grafts (SVG) after CABG.
- To test the hypothesis that diabetes negatively affects long-term graft patency.
Main Methods:
- Analysis of 57,961 patients undergoing primary isolated CABG between 1972 and 2011.
- Inclusion of 1,372 diabetic and 10,147 non-diabetic patients with postoperative angiograms.
- Longitudinal nonlinear mixed-effects modeling to assess graft patency over time for 7,903 ITA and 20,066 SVG grafts.
Main Results:
- Internal thoracic artery (ITA) graft patency remained high and stable over 20 years, with no significant difference between diabetic and non-diabetic patients (96-97% patency).
- Saphenous vein graft (SVG) patency declined significantly over 20 years in both groups, with similar rates observed between diabetic and non-diabetic patients (41-42% patency at 20 years).
- After adjustment, diabetes was associated with higher early ITA graft patency but similar late patency; early and late SVG patency were similar regardless of diabetes status.
Conclusions:
- Contrary to the initial hypothesis, diabetes does not adversely affect long-term bypass graft patency.
- Internal thoracic artery (ITA) grafts demonstrate superior and durable long-term patency, irrespective of diabetic status.
- Maximizing the use of ITA grafts in CABG patients is recommended due to their excellent long-term outcomes, even in those with diabetes.
Background:
Nearly 50% of patients undergoing coronary artery bypass grafting have diabetes. However, little is known about the influence of diabetes on long-term patency of bypass grafts. Because patients with diabetes have more severe coronary artery stenosis, we hypothesized that graft patency is worse in patients with than without diabetes.
Objectives:
This study sought to examine the influence of diabetes on long-term patency of bypass grafts.
Methods:
From 1972 to 2011, 57,961 patients underwent primary isolated coronary artery bypass grafting. Of these, 1,372 pharmacologically treated patients with diabetes and 10,147 patients without diabetes had 15,887 postoperative angiograms; stenosis was quantified for 7,903 internal thoracic artery (ITA) grafts and 20,066 saphenous vein grafts. Status of graft patency across time was analyzed by longitudinal nonlinear mixed-effects modeling.
Results:
ITA graft patency was stable over time and similar in patients with and without diabetes: at 1, 5, 10, and 20 years, 97%, 97%, 96%, and 96% in patients with diabetes, and 96%, 96%, 95%, and 93% in patients without diabetes, respectively (early p = 0.20; late p = 0.30). In contrast, saphenous vein graft patency declined over time and similarly in patients with and without diabetes: at 1, 5, 10, and 20 years, 78%, 70%, 57%, and 42% in patients with diabetes, and 82%, 72%, 58%, and 41% in patients without diabetes, respectively (early p < 0.002; late p = 0.60). After adjusting for patient characteristics, diabetes was associated with higher early patency of ITA grafts (odds ratio: 0.63; 95% confidence limits: 0.43 to 0.91; p = 0.013), but late patency of ITA grafts was similar in patients with and without diabetes (p = 0.80). Early and late patency of saphenous vein grafts were similar in patients with and without diabetes (early p = 0.90; late p = 0.80).
Conclusions:
Contrary to our hypothesis, diabetes did not influence long-term patency of bypass grafts. Use of ITA grafts should be maximized in patients undergoing coronary artery bypass grafting because they have excellent patency in patients with and without diabetes even after 20 years.
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