Case conference: How to treat the diabetic patients with　coronary artery disease and a SYNTAX score more than 23
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Percutaneous coronary intervention (PCI) in diabetes mellitus (DM) patients is associated with higher rates of stent restenosis and major adverse cardiovascular events (MACEs) compared to PCI in non-DM patients, and both the short- and long-term outcomes of treatment are poor. Impairment of the vascular endothelium by chronic hyperglycemia, which magnifies the inflammatory response and accelerates cellular proliferation, and the existence of pathological conditions that aggravate vascular impairment, such as accentuation of the blood coagulation system, have been reported to be the causative factors, and this remains a problem despite the emergence of the drug-eluting stent (DES) and a decline in stent restenosis. Although suppression of the onset of cardiovascular disease (CVD) in the long-term by proactive glycemic control using insulin and sulfonylurea (SU) agents has been established, as proven by studies such as UKPDS 80, the Framingham Study and DCCT/EDIC, there has been no difference in the incidence of cardiovascular events over follow-up periods of less than 10 years. The incidence of stent restenosis and/or MACE can be reduced by intensive glycemic control in diabetic patients, while the Diabetes Control and Complications Trial (DCCT) and Epidemiology of Diabetes Interventions and Complications (EDIC) and UKPDS80 studies have reported that, due to “metabolic memory (Legacy)” effects, intensive glycemic control can not readily reduce the occurrence of CVD. The SYNTAX score, which was first used in the landmark SYNTAX trial, has emerged as a reproducible angiographic tool for quantifying the extent of coronary artery disease based on the location and complexity of each lesion. The SYNTAX score has been validated with regard to its utility in predicting PCI outcomes, and the addition of clinical variables to the SYNTAX score has been shown to improve its ability to predict adverse outcomes. However, the ability of this score to predict medium or longer-term survival after PCI has not been evaluated. Can glycemic control or the SYNTAX score predict stent restenosis and MACE? We present several cases and discuss the applicability of the SYNTAX score.