The invasive intracoronary imaging assessment of left main coronary artery disease

Left main coronary artery disease is associated with an unfavorable prognosis. Evidence-based decision making regarding the optimal revascularization strategy in patients with left main disease has become a challenge, in view of the recently published data. An improvement in outcomes following left main percutaneous interventions could be achieved by reducing the rate of repeat target lesion revascularization through stent optimization techniques. In the setting of left main disease, procedural guidance by intravascular ultrasound or optical coherence tomography is essential for good long-term results, in such a way that intravascular imaging has gained more of a therapeutic connotation. Besides stent optimization, intracoronary imaging quantifies lesion severity, guides lesion preparation through morphological data, facilitates stent selection through accurate vessel sizing, identifies the landing zones, diagnoses acute vessel wall complications such as stent-related edge dissection or intramural hematoma, and defines procedural success.This review focuses on the two main intracoronary imaging techniques used for diagnostic evaluation and procedural guidance in left main coronary artery disease: intravascular ultrasound and optical coherence tomography. Based on the most recently published data, the review discusses each technique’s advantages and pitfalls, and summarizes their indications.

Abstract 15409: The Need for Lesion-specific Stent Optimization Criteria in Intravascular Ultrasound-guided Intervention for Diffuse Long Coronary Lesions: An Individual Patient-level Pooled Analysis of Four Randomized Controlled Trials

Introduction: Achieving stent optimization on intravascular ultrasound (IVUS) is associated with favorable clinical outcomes in new-generation drug-eluting stents (DESs) implantation. Little is known about the stent optimization criteria in lesion subsets assorted according to vessel size and lesion length. Hypothesis: We hypothesized lesion-specific IVUS criteria could provide a better prediction for the outcomes after DES implantation for diffuse coronary lesions. Methods: From four randomized trials comparing IVUS and angiography guidance in long coronary lesions, a total of 1,194 patients who underwent IVUS-guided intervention with DESs ≥26 mm in length were included. Primary endpoint was a major adverse cardiac event (MACE), defined as a composite of cardiovascular death, myocardial infarction, target vessel revascularization, or stent thrombosis at 1 year following intervention. Results: MACE occurred in 41 (3.4%) patients. Among possible combinations of absolute and relative expansion criteria, the combination best predicting MACE was minimal stent area (MSA) ≥5.4 mm 2 or 80% of mean lumen area (MLA) (Youden index=0.250) in overall patients. In 2x2 factorial subgroup analyses, the MSA cutoff was 4.9 mm 2 or 85% of MLA for shorter (<30 mm) lesions with a smaller vessel diameter (reference vessel diameter [RVD] <3.0 mm) (Index=0.616) and 5.6 mm 2 or 85% for shorter lesions with a larger vessel diameter (RVD ≥3.0 mm) (Index=0.211). In longer lesions (≥30 mm), the MSA cutoff was 5.5 mm 2 or 70% of MLA for smaller vessels (RVD <3.0 mm) (Index=0.469), and 6.2 mm 2 or 70% for larger vessels (RVD ≥3.0 mm) (Index=0.578). Conclusions: When IVUS is used to optimize DES implantations for long coronary stenoses, applying different criteria according to angiographic parameters might improve the outcomes. In relatively longer lesions with a larger vessel diameter, pursuing to achieve a higher absolute MSA value rather than relative expansion might be more important.

Using individualized three-dimensional printed airway models to guide airway stent implantation

Airway stents are used to manage central airway obstructions by restoring airway patency. Current manufactured stents are limited in shape and size, which pose issues in stent fenestrations needed to be manually created to allow collateral ventilation to airway branches. The precise location to place these fenestrations can be difficult to predict based on 2-dimensional computed tomography images. Inspiratory computed tomography scans were obtained from 3 patients and analysed using 3D-Slicer™, Blender™ and AutoDesk® Meshmixer™ programmes to obtain working 3D-airway models, which were 3D printed. Stent customizations were made based on 3D-model dimensions, and fenestrations into the stent were cut. The modified stents were then inserted as per usual technique. Two patients reported improved airway performance; however, stents were later removed due to symptoms related to in-stent sputum retention. In a third patient, the stent was removed a few weeks later due to the persistence of fistula leakage. The use of a 3D-printed personalized airway model allowed for more precise stent customization, optimizing stent fit and allowing for cross-ventilation of branching airways. We determine that an airway model is a beneficial tool for stent optimization but does not prevent the development of some stent-related complications such as airway secretions.