New Stent Technologies

Balloon angioplasty of the coronary arteries was first developed in the 1970s as an alternative means of revascularization to coronary artery bypass surgery. A major drawback with balloon angioplasty alone was the high rate of abrupt vessel closure resulting from acute arterial recoil and coronary artery dissection. The introduction of bare metal stents (BMS) in the early 1990s revolutionized percutaneous coronary intervention (PCI), reducing rates of acute vessel closure associated with balloon angioplasty from >5% to <1%. With the resultant reduction in periprocedural myocardial infarction and the need for emergency coronary artery bypass surgery, coronary stent implantation rapidly became the standard of care for patients undergoing PCI such that balloon angioplasty alone was reserved for situations where stent insertion could not be achieved or was not practical. Indeed, in 2008 coronary stents were implanted in >96% of 800,000 PCI procedures performed in the US. Although effective at preventing abrupt closure, the introduction of the BMS has led to the emergence of two important complications, namely stent thrombosis (abrupt thrombotic occlusion) and in-stent restenosis (luminal narrowing due to neointimal proliferation).