Vascular restoration: Is there a window of opportunity?

The usage of drug eluting stents (DES) has markedly reduced the rates of coronary revascularization procedures compared with bare metal stents (BMS). However, this technology still faces challenges in terms of the prevention of late stent thrombosis, major adverse cardiac events (MACE) progression, and the catch-up phenomenon of restenosis. Restoration of endothelial function upon after stenting, therefore, is the key to mitigating the risk of these toxicities and determining the level of the efficacy and safety of an implant. Review of the clinical studies of multiple DES, has suggested that there exists a window of opportunity, within the first two to three months after stent implantation, for restoring vascular function. If re-endothelialization reaches sufficient level within this period, vascular restoration can occur; however, if this opportunity is missed, re-endothelialization is unlikely to reach the level of endothelial maturation necessary to prevent the late stent thrombosis, MACE progression and the catch-up on restenosis. This hypothesis could aid in explaining variable clinical responses for revascularization treatments such as plain old balloon angioplasty (POBA), BMS, or DES. Patients could be grouped according to responses to the different treatment modalities: for Type 1 patients, POBA is sufficient and safe because they possess the capacity with effective endothelial response; for Type 2 patients, re-endothelialization occurs within the window but BMS are needed to maintain the arterial lumen open; for Type 3 individuals, overly accelerated vascular smooth muscle proliferation render sufficient re-endothelialization impossible. Designing based on this principle predicts that the next technology advancement for the interventional cardiology will not be biodegradable DES by default, but rather a DES that can spur early restoration of the endothelial function within the window period.