Novel predictors of stent under-expansion regarding calcified coronary lesions assessed by optical coherence tomography

Effectiveness and Safety of a Novel Intravascular Lithotripsy System for Severe Coronary Calcification: The CALCI-CRACK Trial

BACKGROUND

Intravascular lithotripsy is effective and safe for managing coronary calcification; however, available devices are limited, and complex lesions have been excluded in previous studies. This study aimed to investigate the effectiveness and safety of a novel intravascular lithotripsy system for severe calcification in a population with complex lesions.

METHODS

CALCI-CRACK (treatment of severe calcified coronary lesions with a novel intracoronary shock wave lithotripsy system) (ChiCTR2100052058) was a prospective, single-arm, multicentre study. The primary end point was the procedural success rate. Major safety end points included major adverse cardiovascular events (MACE) and target lesion failure (TLF) at 30 days and 6 months, and severe angiographic complications. Calcification morphology was assessed in the optical coherence tomography (OCT) subgroup.

RESULTS

In total, 242 patients from 15 high-volume Chinese centres were enrolled, including 26.45% of patients with true bifurcation lesions, 3.31% with severely tortuous vessels, and 2.48% with chronic total occlusion, respectively. The procedural success rate was 95.04% (95% confidence interval 91.50%-97.41%), exceeding the prespecified performance goal of 83.4% (P < 0.001). The 30-day and 6-month MACE rates were 4.13% and 4.55%, respectively. TLF rates at those time points were 1.24% and 1.65%, respectively. Severe angiographic complications occurred in 0.42% of patients. In the OCT subgroup (n = 93), 93.55% of calcified lesions were fractured, and minimal lumen area increased from 1.55 ± 0.55 mm2 to 4.91 ± 1.22 mm2 after stent implantation, with acute gain rate of 245 ± 102%.

CONCLUSIONS

The novel intravascular lithotripsy system is effective and safe for managing severely calcified coronary lesions in a cohort that included true bifurcation lesions, severely tortuous vessels, and chronic total occlusion.

CLINICAL TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR), number ChiCTR2100052058.

A Review Paper on Optical Coherence Tomography Evaluation of Coronary Calcification Pattern: Is It Relevant Today?

The process of coronary calcification represents one of the numerous pathophysiological mechanisms involved in the atherosclerosis continuum. Optical coherence tomography (OCT) represents an ideal imaging modality to assess plaque components, especially calcium. Different calcification patterns have been contemporarily described in both early stages and advanced atherosclerosis. Microcalcifications and spotty calcifications correlate positively with macrophage burden and inflammatory markers and are more frequently found in the superficial layers of ruptured plaques in acute coronary syndrome patients. More compact, extensive calcification may reflect a later stage of the disease and was traditionally associated with plaque stability. Nevertheless, a small number of culprit coronary lesions demonstrates the presence of dense calcified plaques. The purpose of the current paper is to review the most recent OCT data on coronary calcification and the interrelation between calcification pattern and plaque vulnerability. How different calcified plaques influence treatment strategies and associated prognostic implications is of great interest.

Optical coherence tomography-derived predictors of stent expansion in calcified lesions

BACKGROUND

Severe coronary artery calcification is associated with stent underexpansion and subsequent stent failure.

AIMS

We aimed to identify optical coherence tomography (OCT)-derived predictors of absolute (minimal stent area [MSA]) and relative stent expansion in calcified lesions.

METHODS

This retrospective cohort study included patients who underwent percutaneous coronary intervention (PCI) with OCT assessment before and after stent implantation between May 2008 and April 2022. Pre-PCI OCT was used to assess calcium burden and post-PCI OCT was used to assess absolute and relative stent expansion.

RESULTS

A total of 361 lesions in 336 patients were analyzed. Target lesion calcification (defined as OCT-detected maximum calcium angle ≥ 30°) was present in 242 (67.0%) lesions. Following PCI, median MSA was 5.37 mm² in calcified lesions and 6.24 mm² in noncalcified lesions (p < 0.001). Median stent expansion was 78% in calcified lesions and 83% in noncalcified lesions (p = 0.325). In the subset of calcified lesions, average stent diameter, preprocedural minimal lumen area, and total calcium length were independent predictors of MSA in multivariable analysis (mean difference 2.69 mm² /mm² , 0.52 mm² /mm, and -0.28 mm² /5 mm, respectively, all p < 0.001). Total stent length was the only independent predictor of relative stent expansion (mean difference -0.465% per mm, p < 0.001). Calcium angle, thickness, and the presence of nodular calcification were not significantly associated with MSA or stent expansion in multivariable analyses.

CONCLUSION

Calcium length appeared to be the most important OCT-derived predictor of MSA, whereas stent expansion was mainly determined by total stent length.

Impact of ultrasound reverberation in calcified coronary arteries: Intravascular ultrasound study

BACKGROUND AND AIMS

Intravascular ultrasound (IVUS) often allows us to observe reverberations behind calcification in percutaneous coronary intervention (PCI) to heavily calcified lesions. However, clinical significance of reverberations remains unknown. The aim of this study was to assess the impact of reverberations on stent expansion and clinical outcomes after PCI with rotational atherectomy (RA) to heavily calcified lesions.

METHODS

We considered 250 calcified lesions that underwent IVUS-guided PCI with RA. According to the number of reverberations (NR), those lesions were divided into the high NR (≥3) group (n = 36) and the low NR (≤2) group (n = 214). Stent expansion and the cumulative incidence of ischemia-driven target lesion revascularization (ID-TLR) were compared between the high and low NR groups.

RESULTS

The high NR group showed significantly smaller stent expansion rate than the low NR group (67.7% vs. 75.9%, respectively, p=0.02). The multivariate logistic regression analysis showed that high NR and calcified nodule were significantly associated with stent underexpansion. The incidence of ID-TLR was significantly higher in the high NR group than in the low NR group (p=0.03). In multivariate Cox hazard analysis, high NR and acute coronary syndrome were significantly associated with ID-TLR.

CONCLUSIONS

High NR was significantly associated with stent underexpansion and ID-TLR. When high NR was detected by IVUS, the PCI strategy was be planned carefully to avoid stent underexpansion. The follow-up program of the patients with high NR might need to be scheduled prudently because of the high risk of TLR.

Experience with Optical Coherence Tomography Enhanced by a Novel Software (Ultreon™ 1.0 Software)-The First One Hundred Cases

Introduction: Optical coherence tomography (OCT) intravascular imaging including the latest version Ultreon™ 1.0 Software (Abbott Vascular, Santa Clara, CA, USA), not only improve patients prognosis, but also facilitates improved percutaneous coronary intervention (PCI). Objectives: The aim of the study was to compare procedure related decision making, procedural indices, clinical outcomes according to the extent of stent expansion and assess risk factors of underexpansion in patients treated with PCI using OCT. Methods: The study comprised 100 patients, which were divided in groups according to the extent of stent expansion: <90 (29 patients) and ≥90% (71 patients). Comparison of OCT parameters, selected clinical and procedural characteristics was performed between groups. We assessed clinical outcomes during the follow-up: major adverse cardiovascular events and risk factors of stent underexpansion. Results: Patients from the stent underexpansion group were treated more often in the past with percutaneous peripheral interventions (p=0.02), no other significant differences being noted in general characteristics, procedural characteristics or clinical outcomes comparing both groups. Significant predictors of stent underexpansion assessed by simple linear univariable analysis included: hypercholesterolemia, obstructive bronchial diseases and treatment with inhalators, family history of cardiovascular disease, PCI of other than the left main coronary artery, stent and drug-eluting stent implantation, PCI without drug-eluting balloon, paclitaxel antimitotic agent, greater maximal stent diameter and lower mean Euroscore II value. Univariable logistic regression analysis revealed a correlation between stent underexpansion and greater creatinine serum concentration before [OR: 0.97, 95%CI: 0.95-0.99, p=0.01] and after PCI [OR: 0.98, 95%CI: 0.96-0.99, p=0.02]. Conclusions: Based on the presented analysis, the degree of stent expansion is not related to the selected procedural, OCT imaging indices and clinical outcomes. Logistic regression analysis confirmed such a relationship for creatinine level.