Striking Finding on Diabetes and Bypass Graft Patency

The higher rate of restenosis in the diabetic population is historic and has been reproduced in all studies and with all kinds of stents, but it was only after the FREEDOM trial when we found out about the higher infarction rate with PCI compared to surgery. This is why 50% of patients undergoing CABG are diabetic.

Apart from the above mentioned, there is no information about the influence of diabetes on long term patency of bypass grafts, although it is only logical to assume it involves a higher revascularization rate.

The study analyzed 57961 patients undergoing myocardial revascularization surgery, 15887 of these patients had post-surgical angiogram. Stenosis was quantified in 7903 internal thoracic artery graft and 20066 saphenous vein graft.

Read also: “SOLACI CACI 2017 | PCI vs CABG in Diabetics – Has the Scale Changed?”

Internal thoracic artery grafts presented a stable patency in the long term, both in diabetic and non-diabetic patients (at 1, 2, 5, 10 and 20 years with a 97%, 97%, 96% and 96% patency in diabetic patients and 96%, 96%, 95% and 93% in non-diabetics, respectively).

Vein grafts lost patency in time similarly in diabetics and non-diabetics (1, 2, 5, 10 and 20 years with 78%, 70%, 57% and 42% patency in diabetics and 82%, 72%, 58% and 41% in non-diabetics, respectively).

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After adjusting for multiple variables, long term patency of internal thoracic arteries and saphenous vein grafts resulted similar in diabetic and non-diabetic patients.

Conclusion

Contrary to any hypothesis, diabetes does not influence long term bypass graft patency, neither arterial nor venous. The use of internal thoracic artery grafts could be maximized in all kinds of patients given its excellent patency at 20+ years.

Editorial Comment

Contrary to our expectations, diabetes was not a risk factor of graft patency, neither arterial nor venous. However, the following did play a significant part in early patency: female gender, internal thoracic artery graft to the right coronary artery and non-significant lesion to coronary artery proximal to graft. Late patency predictors were: young age at the time of surgery, asymptomatic status, high triglycerides and vein graft to the circumflex.

Despite the similar patency rate, diabetics had higher post-surgical mortality compared to non-diabetics, and this could be explained by the rest of comorbidities. In the BARI study, cardiac mortality   at 5 years was similar between diabetics and non-diabetics (5.8% vs 4.7%), but non-cardiac death was twice as high (13% vs 5.6%).

Original title: Influence of Diabetes on Long-Term Coronary Artery Bypass Graft Patency.

Reference: Sajjad Raza et al. J Am Coll Cardiol 2017;70:515–24.

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