**5. The importance of atherosclerosis progression in the long-term outcome after myocardial revascularisation**

Atherosclerotic coronary artery disease is a chronic condition that is not limited by revascularisation. The short and long-term outcomes in patients undergoing both percutaneous and surgical revascularisation, are not only determined by stent or graft failure, but also by atherosclerotic disease progression in other territories. A paucity of data exists regarding the impact of atherosclerosis progression on the outcome of patients after revascularisation, and this is particularly evident in

#### *Percutaneous Coronary Intervention in Diabetic Patients DOI: http://dx.doi.org/10.5772/intechopen.94533*

patients with diabetes. The current data regarding atherosclerosis progression after percutaneous revascularisation is limited. One of the studies that address this issue was the study conducted by Cutlip et al. [102] This study included 1228 patients treated with BMS. The cumulative incidence of restenosis events, non-restenosis events, and the overall composite end point up to 5 years was evaluated. In this study, it was demonstrated that the events relating to restenosis increased during the first year, however there was a virtual absence of restenosis thereafter. On the other hand, the rate of non-restenosis events increased during the first year, in parallel to the restenosis events but continued to increase out to 5 years. The two factors that were independently associated with an increased risk of restenosis and non-restenosis events were diabetes and multivessel disease.

Zellweger et al. [103] studied the importance of 5-year coronary disease progression after successful DES stenting. This is a sub-study of the Basket trial and involved 428 consecutive patients randomised to drug-eluting versus bare-metal stents, with successful stenting documented by freedom from symptoms/events and non-ischaemic perfusion defects (PDs) after 6 months. Rest and stress scintigraphy scans were repeated after 60 months. Late events and new perfusion defects in areas remote from stented vessels were recorded. At 5 years follow-up, 37.1% of all events were due to remote MI, or remote repeat revascularisation. In addition, asymptomatic remote perfusion defect accounted for 37.5%. There is also information about the impact of atherosclerosis progression derived from large randomised trials comparing DES vs. BMS. In the 5-years of the SIRIUS (Sirolimus-Eluting Stent in De-Novo Native Coronary Lesions) trial, 28% of MI were located in non-target vessels. In addition, 64% in the SES group and the 42.% in the BMS group of all target vessel revascularisation were non performed in the target lesion [104]. In the 5-year TAXUS IV Treatment of De Novo Coronary Disease Using a Single Paclitaxel-Eluting Stent trial: 45% of all revascularisation in the PES group were due to non-target lesion TVR [105].

The progression of atherosclerosis in diabetics has been specifically assessed by Rozeman et al. [106]. This study included 248 patients (55 diabetics/193 non diabetics) and evaluated the percentage of arteries with new narrowing's at followup angiography following angioplasty. The authors observed that the percentage of new narrowing was more often in diabetic patients compared to non-diabetics (14.8 vs. 9.4%; p = 0.03) and particularly in the arteries previously treated with angioplasty (13.6 vs. 8.5; p = 0.01). The 5 year follow-up of the DIABETES (DIABETes and sirolimus-Eluting Stent) trial, showed that the need for new revascularisation in the SES group was due equally to restenosis and progression of atherosclerosis in other territories [64]. On the other hand, surgical revascularisation also have disease progression [107]. It has been described that the progression is primarily in the proximal segment before the anastomosis (74%) and the majority was proximal coronary occlusion (78%). This pattern of atherosclerosis progression may be mostly asymptomatic in patients with a patent graft and prevents future events due to plaque rupture in the proximal segment of the artery.

This data suggested that the clinical implication of atherosclerosis progression is different in the two-revascularisation strategies and negatively affects patients treated percutaneously, particularly after the first year of clinical follow-up. This has to be taken into account, when comparing long term results of stent implantation versus CABG in patients with multivessel disease. Improvements in both the stent platforms and the adoption of new drug coatings have improved the outcome of patients treated with PCI. However, it is critical, particularly in the diabetic population to improve the secondary prevention strategies to decrease the occurrence of events due to atherosclerosis progression.
