Functional side‐branch stenosis after cross‐over stenting

Abstract

Despite advances in catheter-based technology, coronary artery bifurcations continue to defy operators. In fact for decades, we have been fascinated by the diverse morphology of coronary bifurcations (i.e., degree of angulations, various branch sizes, and patterns of plaque distribution) along with the erratic changes in luminal size exhibited after cross-over stenting. Currently, a large body of evidence supports main branch (MB) stenting with provisional side branch (SB) stenting as the primary strategy for the vast majority of bifurcations [1]. With this strategy, poststenting SB narrowing occurs often. Recently, a serial intravascular ultrasound (IVUS) imaging study elucidated the mechanism responsible for SB narrowing following cross-over stenting [2]. In that study, a reduction in luminal size at the SB ostium site was observed in 78% of bifurcations. This reduction was chiefly related to the modification in bifurcation angles (carina shift) and, to a lesser extent, an increase in plaque burden at the SB ostium site (plaque shift) [2]. Nonetheless, several reports have shown that most jailed SB do not bare physiological significance [1] and may not warrant further intervention [1]. In this issue of Catheterization and Cardiovascular Interventions, Kang et al. further extend the evidence by illustrating the role of these two mechanisms (carina shift and plaque shifts) in the causation of functional stenosis at the SB ostium [3]. In 40 patients undergoing single stent cross-over stenting, 31 (78%) had >10% reduction in minimum luminal area at the SB ostium. In the setting of luminal narrowing, carina shift was found in 97% of cases, whereas the presence of plaque shift was less common. Meanwhile, a fractional flow reserve (FFR) value <0.8 was found only in 6 (15%) patients. In those individuals with functional stenosis, the detection of plaque shift was common (83%), whereas carina shift was not (20%). Importantly, functional SB stenosis was strongly related to the baseline severity (low minimum luminal area and large plaque burden) at the SB ostium and MB carina. These parameters of baseline severity may identify patients at greater risk for plaque shift, and eventually, functional deterioration of the SB lumen. Although these preliminary results highlight the potential use of IVUS for the baseline evaluation of coronary bifurcations, the low rate of functional SB stenosis after crossover stenting along with the recent introduction of very effective and safe drug-eluting stents may argue against the routine use of IVUS during the percutaneous treatment of coronary bifurcations. After many decades, the debate about the precise role of IVUS during percutaneous coronary interventions continues. REFERENCES1. Stankovic G, Lefevre T, Chieffo A, Hildick-Smith D, Lassen JF, Pan M, Darremont O, Albiero R, Ferenc M, Finet G, et al. Consensus from the 7th European Bifurcation Club meeting. EuroIntervention 2013;9:36-45. 2. Kang SJ, Mintz GS, Kim WJ, Lee JY, Oh JH, Park DW, Lee SW, Kim YH, Lee CW, Park SW, et al. Change...