Assessing coronary target lesion length: the Goldilocks approach.

Abstract

The fact that coronary artery disease is a diffuse process [1] poses a challenge to the coronary interventionalist. Should we strive for a ‘normalto-normal’ stent implantation, whereby culprit plaque is completely trapped beneath stent struts and stent edges are embedded in relatively healthy segments of vessel? In the bare metal era, longer stents were associated with greater risk of restenosis [2], making a strategy of ‘spot stenting’ more appealing. Early-generation drug-eluting stents markedly reduced restenosis, but increasing stent length was associated with higher rates of stent thrombosis [3–5]. Conversely, incomplete longitudinal coverage of target lesions is associated with higher frequency of stent edge dissection [6] and restenosis [7]. In the absence of guideline recommendations or randomized trial data supporting routine ‘spot-stenting’ or ‘normal-to-normal’ approaches, decisions regarding stent length are often individualized for different patients and lesions. Direct coronary imaging can supplement the angiographic lumenogram by accurately assessing the true extent of plaque, allowing the operator to cover diseased vessel without implanting excessive length of stent. Intravascular ultrasound (IVUS) readily identifies plaque in the wall of the artery, which may expand outward long before it encroaches on the lumen and is detectible by angiography [8]. It has been estimated that less than 10% of ‘normal’ reference segments by invasive coronary angiography are free of plaque burden by IVUS [9]. Employing IVUS to guide stenting decisions improves patient outcomes. Early and late stent failure can potentially be averted with the detection of major edge dissections and malappo sition, which may be invisible by invasive coronary angiography [10,11]. A large, retrospective study of nearly 3500 patients found that the use of IVUS to optimize stenting resulted in significant reductions in myocardial infarction, stent thrombosis and target vessel revascularization, largely attributed to the use of longer or more appropriately sized stents [12]. Taking IVUS guidance a step further, Morino et al. achieved a very low rate of drug-eluting stent edge restenosis by implanting stent edges in reference segments containing plaque burden <50% [13]. Plaque composition may also influence stent outcomes. Near-infrared spectroscopy (NIRS)