Coronary Artery Disease
Coronary artery disease (CAD) is the most common form of cardiovascular disease and the number one cause of death in the United States and Europe. According to the American Heart Association, CAD affects over 13 million Americans and accounts for over 650,000 deaths annually. CAD is primarily caused by lesions consisting of plaque, or fat-laden cells, in the arteries surrounding heart. As plaque accumulates over time, the diameter of the arterial lumen, or inner channel, narrows, resulting in reduced or stopped blood flow. When this occurs in arteries supplying blood to the heart, it can cause chest pain, a heart attack, or even death. Risk factors for CAD include old age, smoking, diabetes, obesity, sedentary lifestyle, and a positive genetic history. CAD is most often treated by percutaneous transluminal coronary angioplasty (PTCA). The most common PTCA procedure, undergone by almost a million patients per year in the US alone, involves stent implantation.1, 2
A coronary stent is a small tubular mesh that is inserted into the diseased coronary artery to reestablish the blood flow. Stents were developed for lesions located on straight segments of the coronary arteries. However, approximately 20% of stent procedures involve one or more so called bifurcation lesions, where a side branch comes off the major artery.3 Stents designed for straight vessel are ill-suited for the treatment of this type of lesions. Dedicated bifurcation stents developed to date have not been widely adopted because (i) most impose a pre-determined treatment strategy that does not cover the broad, heterogeneous range of bifurcation lesions and (ii) the lack of simplicity and ease of use resulting in cumbersome procedures.
Currently, there is no approved treatment for bifurcation lesions in the US. Instead, physicians have developed different techniques, such as T-stenting, Culotte, V-stenting, SKS, and Crush, to modify conventional straight vessel stents to treat bifurcation lesions. All of these applications are off-label (i.e. different from the FDA-approved instructions for use of the product) and require the physician to have tremendous technical skill. Clinical results for such treatments are suboptimal, with higher rates of complications and restenosis. As a result, many patients suffering from bifurcation lesions undergo coronary artery bypass surgeries.
1. Merrill Lynch; Updated working worldwide coronary stent market model, 2006
2. Morgan Stanley; The 2005 investor's guide to interventional cardiology
3. TriReme Medical Inc; Bifurcation stents market analysis, 2006
PTA — Percutaneous Transluminal Angioplasty