Optimizing Percutaneous Coronary Intervention in Calcified Lesions
Insights From Optical Coherence Tomography of Atherectomy
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Optimal coronary stent implantation is among the few successful strategies in preventing stent failures, notably in-stent restenosis and stent thrombosis.1 Understanding the intravascular milieu is a prerequisite for optimization of percutaneous coronary intervention (PCI). Calcified lesions limit stent expansion, the most robust predictor of target lesion revascularization, and are thus associated with worst outcomes.2 Coronary angiography is a poor discriminator of calcium distribution and thickness. Reliance on angiography to guide PCI and define procedural success in severe coronary calcification is associated with poor outcomes.3 Both intravascular ultrasound and optical coherence tomography (OCT) enable detailed evaluation of cross-sectional calcium distribution (angle of calcium), and OCT provides additional information on calcium thickness. The combination of large calcium angle (>270°) and thickness (>670 μm) predicts nondilatable lesions.4 OCT is the ideal method to capture these parameters and indicate or defer the use of atherectomy before stent implantation and guide optimization of PCI.
Intervention OCT Imaging
Preintervention OCT imaging delineates plaque constituents and provides accurate measurements of the minimal lumen area, lesion length, and reference vessel diameters, as well as visualization of the projected stent landing zones. These parameters can be used for procedural planning, including proper lesion preparation and stent sizing. Knowledge of plaque characteristics can be used to select a plaque modification strategy prior to stent implantation and to minimize stent edge dissection at the stent landing zone.5 Calcified lesions pose a bigger challenge, with difficult device delivery, suboptimal stent expansion, and increased procedural time and complications. Although atherectomy facilitates stent delivery and improves procedural success and acute lumen gain, long-term outcomes in severely calcified lesions are not improved with the routine use of angiographically guided ablative techniques in the drug eluting stent era.6 Indiscriminate use of atherectomy can also increase procedural complications. Intravascular frequency domain OCT is the …