Optical coherence tomography-guided percutaneous coronary intervention: a review of current clinical applications

RapidBrachyIVBT: A dosimetry software for patient-specific intravascular brachytherapy dose calculations on optical coherence tomography images

BACKGROUND

Coronary artery disease is the most common form of cardiovascular disease. It is caused by excess plaque along the arterial wall, blocking blood flow to the heart (stenosis). A percutaneous coronary intervention widens the arterial wall with the inflation of a balloon inside the lesion area and leaves behind a metal stent to prevent re-narrowing of the artery (restenosis). However, in-stent restenosis may occur due to damage to the arterial wall tissue, triggering neointimal hyperplasia, producing fibrotic and calcified plaques and narrowing the artery again. Drug-eluting stents, which slowly release medication to inhibit neointimal hyperplasia, are used to prevent in-stent restenosis but fail up to 20% of cases. Coronary intravascular brachytherapy (IVBT), which uses β $\beta$ -emitting radionuclides to prevent in-stent restenosis, is used in these failed cases to prevent in-stent restenosis. However, current clinical dosimetry for IVBT is water-based, and heterogeneities such as the guidewire of the IVBT device, fibrotic and calcified plaques and stents are not considered.

PURPOSE

This study aimed to develop a Monte Carlo-based dose calculation software, accounting for patient-specific geometry from Optical Coherence Tomography (OCT) images.

METHODS

RapidBrachyIVBT, a Monte Carlo dose calculation software based on the Geant4 toolkit v. 10.02.p02, was developed and integrated into RapidBrachyMCTPS, a treatment planning system for brachytherapy applications. The only commercially available IVBT delivery system, the Novoste Beta-Cath 3.5F, with a90 Sr 90 Y $^{90}{\rm Sr}^{90}{\rm Y}$ source train, was modeled with 30, 40, and 60 mm source train lengths. The software was validated with published TG-149 parameters compared to Monte Carlo simulations in water. The dose calculation engine was tested with OCT images from a patient undergoing coronary IVBT for recurrent in-stent restenosis at Brigham and Women's Hospital in Boston, Massachusetts. Considering the heterogeneities, the images were segmented and used to calculate the absorbed dose to water and the absorbed dose to medium. The prescribed dose was normalized to 23 Gy at 2.0 mm from the source center, which is the target volume in IVBT.

RESULTS

The dose rate values in water obtained using RapidBrachyIVBT aligned with TG-149 consensus values, showing agreement within a range of 0.03% to 1.7%. Considering the heterogeneities present in the patient's OCT images, the absorbed dose in the entire artery segment was up to 77.5% lower, while within the target volume, it was up to 56.6% lower, compared to the dose calculated in a homogeneous water phantom.

CONCLUSION

RapidBrachyIVBT, a Monte Carlo dose calculation software for IVBT, was developed and successfully integrated into RapidBrachyMCTPS, a treatment planning system for brachytherapy applications, where accurate attenuation of the absorbed dose by heterogeneities is considered.

State-of-the-art percutaneous coronary intervention for left main coronary artery disease in Japan

Percutaneous coronary intervention for left main coronary artery disease (LM-PCI) represents a high-risk yet life-saving procedure that has evolved significantly over the years. This review outlines the current state-of-the-art practices for LM-PCI in Japan in detail, emphasizing the integration of coronary physiology and intracoronary imaging alongside with evidence-based standardized technique using latest drug-eluting stents. These advancements enable precise lesion assessment, stent sizing, and optimal deployment, thereby enhancing procedural safety and efficacy. Despite discrepancies between current guidelines favoring coronary artery bypass grafting and real-world practice trends towards increased LM-PCI adoption, particularly in elderly populations with multiple comorbidities, careful patient selection and procedural planning are critical. Future perspectives include further refining LM-PCI through conducting randomized controlled trials integrating advanced techniques and addressing the issue of ostial left circumflex lesions and nationwide standardization of medical care for LM disease.

Prospective investigation of calcium score in optical coherence tomography-guided revascularization to identify lesions with low risk for stent under expansion: the CORAL study

The optical coherence tomography (OCT)-based calcium scoring system was developed to guide optimal lesion preparation strategies for percutaneous coronary intervention (PCI) of calcified lesions. However, the score was derived retrospectively, and a prospective investigation is lacking. The CORAL (UMIN000053266) study was a single-arm, prospective, multicenter study that included patients with calcified lesions with OCT-calcium score of 1-2 to investigate whether these lesions could be optimally treated with a balloon-only preparation strategy using a non-compliant/scoring/cutting balloon. The primary endpoint was strategy success (successful stent placement with a final percent diameter stenosis [%DS] < 20% and Thrombolysis In Myocardial Infarction flow grade III without crossover to rotational atherectomy/orbital atherectomy/intravascular lithotripsy [RA/OA/IVL]). A superiority analysis for the primary endpoint was performed by comparing the study cohort with a performance goal of 83.3%. One hundred and eighteen patients with 130 lesions were enrolled. The mean age was 79.0 ± 10.3 years, and 79 patients (66.9%) were male. The OCT-calcium score was 1 for 81 lesions (62.3%) and 2 for 49 lesions (37.7%). The %DS improved from 47.0 ± 14.8% preprocedure to 11.1 ± 5.6% postprocedure. Stent expansion ≥ 70% was achieved in 90.2%. The strategy success rate was 93.1% (95% confidence interval: 87.3-96.8), and superiority against the performance goal was achieved without any crossover to RA/OA/IVL (P = 0.0027). The OCT-calcium score could identify mild/moderately calcified lesions treatable by PCI with the balloon-first strategy using a non-compliant/scoring/cutting balloon for predilatation, with a high strategy success rate. These results support the intravascular imaging-based treatment algorithm for calcified lesions proposed by CVIT.

The Combinations of the Patterns of Non-adherence to Anti-platelet Regimen in Stented Patients (PARIS) and Coronary Revascularization Demonstrating Outcome Study in Kyoto (CREDO-Kyoto) Thrombotic and Bleeding Risk Scores on Clinical Outcomes in Patients with Acute Myocardial Infarction

Objective The Patterns of Non-adherence to Anti-platelet Regimen in Stented Patients (PARIS) and Coronary Revascularization Demonstrating Outcome Study in Kyoto (CREDO-Kyoto) thrombotic and bleeding risk scores were established to predict ischemic and bleeding events in patients undergoing percutaneous coronary intervention (PCI). However, whether or not the combination of these risk scores is predictive of clinical outcomes is unclear. Methods This bicenter registry included a total of 1,098 patients with acute myocardial infarction (MI) undergoing primary PCI. Patients were divided into three groups according to the PARIS and CREDO-Kyoto thrombotic and bleeding risk scores. The study endpoints included the rates of both ischemic (cardiovascular death, recurrent MI, and ischemic stroke) and major bleeding (Bleeding Academic Research Consortium type 3 or 5) events at two years. Results Two years after primary PCI, ischemic and major bleeding events occurred in 17.3% and 10.2% of patients, respectively. The higher-risk categories of PARIS and CREDO-Kyoto scores were associated with increased risks of ischemic and bleeding events. The rates of ischemic and major bleeding events progressively increased with the increase in risk categories in the two risk scoring systems. In the receiver operating characteristic curve analysis, the addition of CREDO-Kyoto thrombotic and bleeding risk scores to PARIS scores significantly improved diagnostic ability in predicting ischemic (area under the curve: 0.59 vs. 0.63, p=0.01) and bleeding (area under the curve: 0.65 vs. 0.68, p=0.01) events. Conclusion The combinations of the PARIS and CREDO-Kyoto risk scores might be useful for evaluating ischemic and bleeding risks in patients with acute MI undergoing primary PCI.

Very Late Stent Thrombosis Complicating Immune Thrombocytopenia: Insights From Optical Coherence Tomography and Thrombopathology

Immune thrombocytopenia (ITP) carries bleeding and thrombotic risks; however, thromboses associated with ITP have not been histologically examined. This report presents optical coherence tomography images of the culprit lesion and histology of coronary aspirates in very late stent thrombosis complicating severe ITP, providing evidence of platelet-rich thrombus formation. (Level of Difficulty: Advanced.).

Prediction of the debulking effect of rotational atherectomy using optical frequency domain imaging: a prospective study

This study determined the predictive accuracy of optical frequency domain imaging (OFDI) on debulking effects of rotational atherectomy (RA) and compared the predictive accuracy of OFDI catheter-based with Rota wire-based prediction methods. This prospective, single-center, observational study included 55 consecutive patients who underwent OFDI-guided RA. On pre-RA OFDI images, a circle, identical to the Rota burr was drawn at the center of the OFDI catheter (OFDI catheter-based prediction method) or wire (wire-based prediction method). The area overlapping the vessel wall was defined as the predicted ablation area (P-area). The actual ablated area (A-area) was measured by superimposing the OFDI images before and after RA. The overlapping P-area and A-area were defined as overlapped ablation area (O-area), and the predictive accuracy was evaluated by %Correct area (O-area/P-area) and %Error area (A-area  - O-area/A-area). The median %Correct and %Error areas were 47.8% and 41.6%, respectively. Irrelevant ablation (low %Correct-/high % Error areas) and over ablation (high %Correct-/high % Error areas) were related to deep vessel injury and intimal flap outside the P-area. The predictive accuracy was better in the OFDI catheter-based prediction method than the wire-based prediction method in the cross sections where the OFDI catheter and wire came in contact. However, it was better in the latter than the former where the OFDI catheter and wire were not in contact. OFDI-based simulation of the RA effect is feasible though accuracy may be affected by the OFDI catheter and wire position. OFDI-based simulation of RA effect might reduce peri-procedural complications during RA.

Optical coherence tomography factors for adverse events in patients with severe coronary calcification

BACKGROUND

Severe coronary calcification is a factor for worse outcomes after percutaneous coronary intervention.

AIMS

To identify factors of pre- and post-stent optical coherence tomography (OCT) for device-oriented clinical endpoints (DoCE) in patients with severely calcified lesions requiring drug-eluting stent (DES) implantation.

METHODS

A total of 237 consecutive patients with stable coronary disease who underwent OCT imaging of severe coronary lesions were included. Lesions with a maximum calcium angle >180°, maximum calcium thickness > 0.5 mm, and calcium length > 5 mm were defined as having severe calcification.

RESULTS

The prevalence of eruptive calcified nodules (41% vs. 18%, p = 0.002) and medial dissection with calcified flaps (59% vs. 26%, p < 0.001) was significantly higher in patients with DoCE (n = 34) than those without DoCE (n = 203). Multivariate analyses demonstrated that the presence of a medial dissection with calcified flap within the DES-implanted segment was independently associated with a higher incidence of DoCE (odds ratio, 3.367; 95% confidence interval, 1.503-7.543; p = 0.003). The combined presence of eruptive calcified nodules and medial dissection with calcified flaps was associated with a higher incidence of DoCE (p < 0.001) during a median of 756 days after DES implantation.

CONCLUSIONS

OCT-defined severely calcified lesions with eruptive calcified nodules and medial dissection with calcified flaps were associated with a higher incidence of DoCE after DES implantation.

Relationship between coronary artery calcium score and bleeding events after percutaneous coronary intervention in chronic coronary syndrome

The relationship between coronary artery calcium (CAC) and bleeding events after percutaneous coronary intervention (PCI) in patients with chronic coronary syndrome (CCS) is not well established. This study aimed to examine the association between CAC scores and clinical outcomes after PCI in patients with CCS. This retrospective observational study included 295 consecutive patients who underwent multidetector computer tomography and were scheduled for their first elective PCI. Patients were categorized into two groups based on the CAC scores (low: ≤ 400 or high: > 400). The bleeding risk was evaluated using the Academic Research Consortium for High Bleeding Risk (ARC-HBR) criteria. The primary clinical outcome was a major bleeding event within 1 year after PCI, defined as Bleeding Academic Research Consortium (BARC) 3 or 5. The high CAC score group had a higher proportion of patients meeting the ARC-HBR criteria than the low CAC score group (52.7% vs. 31.3%, p < 0.001). Kaplan-Meier survival analysis showed that the incidence of major bleeding events was higher in the high CAC score group as compared to the low CAC score group (p < 0.001). Furthermore, multivariate Cox regression anal ysis revealed that a high CAC score was an independent determinant of major bleeding events during the first year after PCI. A high CAC score is significantly associated with the incidence of major bleeding events after PCI in CCS patients.

Relation of GRACE Risk Score to Coronary Lipid Core Plaques in Patients with Acute Coronary Syndrome

The GRACE risk score is established to predict thrombotic events in patients with acute coronary syndrome (ACS). Although thrombotic events including myocardial infarction after ACS are mainly attributable to vulnerable plaque formation, whether the GRACE score correlates with coronary lipid-rich plaque is unclear. A total of 54 patients with ACS undergoing primary percutaneous coronary intervention under near-infrared spectroscopy intravascular ultrasound (NIRS-IVUS) guidance were included in a prospective manner. Patients were divided into two groups according to the median of the GRACE risk score. Coronary lipid plaques in the target vessel were assessed by NIRS-IVUS with lipid core burden index (LCBI) and a maximum LCBI in 4 mm (maxLCBI4mm). The receiver operating characteristics (ROC) curve analysis was performed based on the major adverse cardiovascular events as an exploratory analysis. The GRACE risk score was significantly and positively correlated with LCBI (r = 0.31, p = 0.03) and maxLCBI4mm (r = 0.38, p = 0.006). LCBI (111.7 ± 85.7 vs. 169.0 ± 83.5, p = 0.02) and maxLCBI4mm (428.5 ± 227.1 vs. 600.6 ± 227.7, p = 0.009) in the target vessel were significantly higher in the high GRACE risk score group than their counterpart. In the ROC curve analysis, LCBI and maxLCBI4mm were predictive for clinical events. In conclusion, the higher GRACE risk score may serve as a discriminator of risk comprising more lipid-rich plaques as an underlying mechanism of an increased risk of thrombotic events after ACS. In patients with ACS, the higher GRACE risk score was significantly and modestly associated with greater coronary lipid plaques in the target vessel.

Treatment strategies of acute myocardial infarction: updates on revascularization, pharmacological therapy, and beyond

Owing to recent advances in early reperfusion strategies, pharmacological therapy, standardized care, and the identification of vulnerable patient subsets, the prognosis of acute myocardial infarction has improved. However, there is still considerable room for improvement. This review article summarizes the latest evidence concerning clinical diagnosis and treatment of acute myocardial infarction.

Association of Microluminal Structures Assessed by Optical Coherence Tomography With Local Inflammation in Adjacent Epicardial Adipose Tissue and Coronary Plaque Characteristics in Fresh Cadavers

BACKGROUND

Coronary intraplaque microluminal structures (MS) are associated with plaque vulnerability, and the inward progression of vascular inflammation from the adventitia towards the media and intima has also been demonstrated. Therefore, in the present study we investigated the relationships among MS, local inflammation in adjacent epicardial adipose tissue (EAT), and coronary plaque characteristics.

METHODS AND RESULTS

Optical coherence tomography (OCT) revealed MS in the left anterior descending coronary artery in 10 fresh cadaveric hearts. We sampled 30 lesions and subdivided them based on the presence of MS: MS (+) group (n=19) and MS (-) group (n=11). We measured inflammatory molecule levels in the adjacent EAT and percentage lipid volume assessed by integrated backscatter intravascular ultrasound in each lesion. The expression levels of vascular endothelial growth factor B and C-C motif chemokine ligand 2 were significantly higher in the MS (+) group than in the MS (-) group (0.9±0.7 vs. 0.2±0.2 arbitrary units (AU), P=0.04 and 1.5±0.5 vs. 0.6±0.7 AU, P=0.02, respectively). Percentage lipid volume was significantly higher in the MS (+) group than in the MS (-) group (38.7±16.5 vs. 23.7±10.9%, P=0.03).

CONCLUSIONS

Intraplaque MS observed on OCT were associated with lipid-rich plaques and local inflammation in the adjacent EAT. Collectively, these results suggest that local inflammation in the EAT is associated with coronary plaque vulnerability via MS.

Derivation of a Novel Scoring System Predicting High Platelet Reactivity on Prasugrel in Patients with Coronary Artery Disease

AIMS

High platelet reactivity (HPR) has been associated with an increased risk of thrombotic events in patients undergoing percutaneous coronary intervention. HPR has been well examined in patients treated with clopidogrel; however, HPR on prasugrel is poorly investigated.

METHODS

Four prospective studies were pooled, in which platelet reactivity on prasugrel was measured using VerifyNow assay; genotyping of CYP2C19 was also performed. Factors associated with HPR on prasugrel were identified using multivariable analysis to develop a risk prediction model.

RESULTS

In total, 180 patients were examined in this study, of whom 51 (28%) had HPR on prasugrel. The multivariable analysis indicated that hypertension, diabetes, hemodialysis, and the number of CYP2C19 loss-of-function (LOF) alleles are significant factors for HPR on prasugrel. These four factors were then incorporated to develop the HHD-GENE score. The receiver operating characteristic curve analysis showed that the HHD-GENE score predicted HPR on prasugrel (area under the curve (AUC) 0.74, best cutoff value 5, p＜0.001). With the best cutoff value, patients with the HHD-GENE score ≥ 5 had a significantly increased risk of HPR on prasugrel than their counterpart (50% vs. 18%, p＜0.001).

CONCLUSIONS

The HHD-GENE score consisting of hypertension, diabetes, hemodialysis, and CYP2C19 LOF alleles may be useful in identifying patients on prasugrel who are at high risk for HPR. External validation is needed to define the clinical utility of this novel scoring system.

Differential Impact of Clinical and Genetic Factors on High Platelet Reactivity in Patients with Coronary Artery Disease Treated with Clopidogrel and Prasugrel

AIM

High platelet reactivity (HPR) is associated with increased risks of thrombotic events in patients with coronary artery disease. The recently developed ABCD-GENE score identified five clinical and genetic factors (age, body mass index, chronic kidney disease, diabetes, and the CYP2C19 loss-of-function allele) for HPR, although the significance of various stages of each factor is unclear.

METHODS

Four prospective studies were pooled, in which platelet reactivity was measured using the VerifyNow assay with clopidogrel and prasugrel; genotyping of CYP2C19 was also performed. Each component of the ABCD-GENE score was divided into three subcategories. VerifyNow P2Y12 reactivity units ＞208 were defined as HPR.

RESULTS

A total of 184 patients were included, of which 111 (60%) and 51 (28%) had HPR with clopidogrel and prasugrel. Chronic kidney disease had an impact on HPR on both clopidogrel and prasugrel, whereas the impact of diabetes was more evident in patients treated with prasugrel. Although the number of CYP2C19 loss-of-function alleles was clearly associated with a likelihood of HPR with clopidogrel, P2Y12 reactivity units with prasugrel treatment were also significantly and progressively higher in patients with more CYP2C19 loss-of-function alleles.

CONCLUSIONS

Clinical and genetic factors had a differential effect on a P2Y12 inhibitor reactivity with clopidogrel and prasugrel in patients with coronary artery disease. The severity of the factors also had a different impact on HPR.

Predictivity of acute kidney injury risk scores for late kidney injury in patients with chronic coronary syndrome

Late rather than acute kidney injury after percutaneous coronary intervention (PCI) has been recently recognized as a predictor of future adverse events in patient with coronary artery disease. The risk-predicting models for acute kidney injury reported by Mehran et al., Bartholomew et al., and Tsai et al. were derived from a large cohort and externally validated, although the applicability of these models for predicting late kidney injury is unknown. A total of 327 patients undergoing elective PCI procedures were included. We calculated the three scores and tested their diagnostic ability for predicting late kidney injury (> 6 months after PCI), defined as an increase in creatinine levels ≥ 0.3 mg/dl or ≥ 50% from baseline. During the median follow-up period of 28 months, 27 (8.3%) patients had late kidney injury. All three scores significantly predicted late kidney injury, among which the score by Tsai et al. had a better diagnostic ability (area under the curve 0.83, best cut-off value 14, p < 0.001). With the best cut-off value, patients with Tsai score ≥ 14 had a significantly higher rate of late kidney injury than their counterpart (27.4% vs. 2.8%, p < 0.001). In conclusion, established risk scores for acute kidney injury may be useful for predicting late kidney injury after PCI in patients with chronic coronary syndrome.

Early vascular healing of ultra-thin strut polymer-free sirolimus-eluting stents in acute coronary syndrome: USUI-ACS study

Ultra-thin strut polymer-free sirolimus-eluting stent (UPF-SES) have two novel characteristics, ultra-thin strut and polymer-free coating, which have the potential to achieve early re-endotherialization. However, a little is known whether early vascular healing of UPF-SES can be achieved in patients with acute coronary syndrome (ACS). The aim of this study was to evaluate the vascular healing after an implantation of UPF-SES in patients with ACS using optical coherence tomography (OCT) at 3 months after the stent implantation. From September 2020 and January 2021, a total of 31 consecutive patients presenting with ACS who underwent OCT-guided percutaneous coronary intervention (PCI) and 3 month follow-up OCT examination were enrolled in the USUI-ACS study. The endpoints of this study were neointimal strut coverage, malapposition, and mean neointimal hyperplasia (NIH) thickness at 3 month follow-up. Over a mean follow-up of 91 days after the initial PCI, the follow-up OCT was examined. The median percentage of covered struts was 98.4% and malapposed struts 0%, and the mean NIH thickness was 80 μm. UPF-SES exhibited an excellent early vascular healing at 3 months in patients with ACS.

Preferable vascular healing of ultrathin strut biodegradable-polymer sirolimus-eluting stents in patients with acute coronary syndrome

This study aimed to compare the strut coverage between Orsiro ultrathin struts biodegradable polymer sirolimus-eluting stents (O-SES) and Xience thin struts durable polymer everolimus-eluting stents (X-EES) in acute coronary syndrome (ACS) patients using optical coherence tomography (OCT). In BIOSTEMI trial, O-SESs were superior to X-EESs with respect to target lesion failure in ACS patients. However, there were few reports comparing intravascular imaging between the two stents in ACS. Between August 2016 and February 2020, 49 lesions from 49 ACS patients who underwent OCT-guided percutaneous coronary intervention were enrolled. We compared vascular healing using OCT between O-SESs and X-EESs at 8 months after stenting. The protocol was approved by the Osaka Rosai Hospital ethics committee. Among 49 lesions, the X-EES group consisted of 24 lesions and the O-SES of 25 lesions. The percentage of covered strut, the percentage of malapposed strut and mean neointimal thickness at 8 months were evaluated. In the 8-month OCT analysis, the proportion of covered strut was significantly higher in the O-SES group than in in the X-EES group (97.3% vs. 92.5%; p = 0.010). On the other hand, there were no significant differences in the frequency of malapposed strut (0.4% vs 0.3%, p = 0.609). The O-SES group had the significantly thinner neointima compared to the X-EES group (60 μm vs 84 μm, p = 0.001). Compared to X-EESs, O-SESs showed better strut coverage and thinner neointima in ACS patients at 8 months follow-up. Ultra-thin strut and silicon carbide passive coating may play a key role in better vascular healing.

Incidence and characteristics of incomplete stent apposition in calcified lesions: An optical coherence tomography study

BACKGROUND

Persistent or late acquired incomplete stent apposition (ISA) may be associated with late or very late stent thrombosis following drug-eluting stent implantation. Presence of calcium at the target lesion may increase the risk of ISA even after rotational atherectomy (RA) followed by stenting with high pressure balloon inflation. The aim of this study is to examine the incidence and characteristics of ISA in heavily calcified lesions.

METHODS

A total of 52 heavily calcified coronary artery lesions requiring RA plus stenting were selected and studied. After successful ablation followed by stent implantation, optical coherence tomography (OCT) was performed to assess stent expansion and apposition. Presence or absence of ISA was examined and maximal stent strut to vessel wall distance (max SV distance) was measured. In lesions with repeated OCT at follow-up, serial changes in ISA were investigated.

RESULTS

ISA was documented in 51 of 52 (98%) lesions. Mean max SV distance was 713 ± 371 μm. In lesions with serial OCT images (n = 11), max SV distance decreased significantly (692.1 ± 420.2 to 462.5 ± 387.0 μm, P < 0.01) but persisted in all but 2 lesions (82%).

CONCLUSIONS

ISA is frequently documented in heavily calcified lesions requiring RA. Significant ISA still persisted with minimal improvement in SV distance at follow-up. Prognostic impact of the persistent ISA in such calcified lesions needs further investigations.

Impact of glycemic variability on coronary and peripheral endothelial dysfunction in patients with coronary artery disease

BACKGROUND

Previous studies have reported that glucose variability leads to endothelial dysfunction and progression of coronary atherosclerosis. However, few studies have directly evaluated the relation between glucose variability and coronary endothelial function in patients with coronary artery disease (CAD).

METHODS

A total of 38 patients with chronic CAD and a history of coronary drug-eluting stent implantation were enroled. Coronary endothelial function was evaluated by measuring the coronary vasoreactivity using quantitative coronary angiography in the segment distal to implanted stent in response to intracoronary acetylcholine (ACh) infusion (10-7 mol/l). Peripheral endothelial function was also assessed with reactive hyperemia index (RHI). The mean amplitude of glycemic excursion (MAGE) was calculated as a primary metric of glucose variability using a flash glucose monitoring system.

RESULTS

Of 38 patients, 17 (45%) had diabetes mellitus. The mean levels of glycated hemoglobin, MAGE, and RHI were 6.3 ± 0.8%, 71.4 ± 29.8 mg/dl, and 1.85 ± 0.63. In the distal segment to coronary stent, lumen diameter was constricted by 0.6 ± 7.3% in response to intracoronary ACh infusion compared to that at baseline. While peripheral endothelial function assessed with RHI was not significantly associated with MAGE (r = -0.16, p = 0.35), coronary endothelial function was correlated with MAGE (r = -0.38, p = 0.02).

CONCLUSION

Greater glucose variability was significantly associated with coronary rather than peripheral endothelial dysfunction in patients with CAD, suggesting an impact of glucose variability on coronary atherosclerosis.

Factors associated with aorto-ostial stent coverage during intravascular ultrasound-guided percutaneous coronary intervention to severely narrowed non-ostial right coronary artery lesions

Introduction

In percutaneous coronary intervention (PCI) to atherosclerotic lesions in the right coronary artery (RCA), coronary artery dissection in the ostium of the RCA is a rare but fatal complication. Stent implantation to the ostium of RCA may be selected for the prevention of aorto-ostial dissection.

Aim

To find factors associated with aorto-ostial stent coverage to mild to moderate ostial stenosis during the treatment of severely narrowed non-ostial RCA lesions.

Material and methods

The primary interest was to find factors associated with ostial stent coverage using multivariate regression analysis. We included 236 patients who underwent intravascular ultrasound (IVUS)-guided PCI to severely narrowed RCA lesions with mild to moderate ostial stenosis, and divided those into the ostial-coverage group (n = 52) and the non-coverage group (n = 184).

Results

The prevalence of continuous ostial plaque detected by intravascular ultrasound (IVUS) was significantly greater in the ostial-coverage group (84.6%) than in the non-coverage group (52.9%) (p < 0.001). Multivariate logistic regression analysis revealed that continuous ostial plaque detected by IVUS (OR = 5.398, 95% CI: 2.322–12.553, p < 0.001) was significantly associated with ostial stent coverage after controlling confounding factors. Ischaemia-driven target vessel revascularization was less frequently observed in the ostial-coverage group than in the non-coverage group, without reaching statistical significance (p = 0.069).

Conclusions

Continuous ostial plaque detected by IVUS was significantly associated with ostial stent coverage to the mild to moderate stenosis when PCI to non-ostial, severely narrowed RCA lesions was performed. The use of IVUS may enhance the safety but may increase the total stent length in PCI to RCA.