Serial longitudinal changes of coronary calcified plaques with clear outer borders under intensive lipid management: insights from optical coherence tomography

Percutaneous coronary intervention (PCI) for calcified lesions is one of the most challenging procedures related to worse clinical outcomes. To stabilize vulnerable plaques, intensive lipid management is recommended; however, the serial changes of calcified plaques under intensive lipid management are unknown. A total of 31 patients (mean age, 63 ± 10 years; men, 29 patients) who underwent PCI with intensive lipid management were retrospectively studied. We evaluated the serial longitudinal changes of calcified plaques with clear outer borders using optical coherence tomography (OCT) at two time points: at the time of PCI (baseline) and the chronic phase. The median interval from PCI to chronic phase was 287 (233-429) days. Twenty-eight patients (90.3%) had increased calcium volume at the chronic phase compared with those at baseline (2.6 [1.3-5.1] vs. 1.8 [0.7-4.3] mm2, p < 0.05), and the median increase rate of calcium volume was 27.4% at the chronic phase. According to the median increase rate of calcium volume (27.4%), patients were divided into the following two groups: rapid progression (≥ 27.4%, RP group) and non-rapid progression (< 27.4%, non-RP group). The RP group had more patients with diabetes, and diabetes was independently associated with rapid progression by multivariate analysis. Furthermore, patients with diabetes had significantly higher changes in calcium index and volume from the baseline to the chronic phase than those without diabetes. Coronary calcification progression during relatively short intervals was observed using OCT even under intensive lipid management. Diabetes was an independent predictor for rapid coronary calcification progression.

Cardiac Optical Coherence Tomography: History, Current Status, and Perspective

For more than 2 decades since the first imaging procedure was performed in a living patient, intravascular optical coherence tomography (OCT), with its unprecedented image resolution, has made significant contributions to cardiovascular medicine in the realms of vascular biology research and percutaneous coronary intervention. OCT has contributed to a better understanding of vascular biology by providing insights into the pathobiology of atherosclerosis, including plaque phenotypes and the underlying mechanisms of acute coronary syndromes such as plaque erosion, neoatherosclerosis, stent thrombosis, and myocardial infarction with nonobstructive coronary arteries. Moreover, OCT has been used as an adjunctive imaging tool to angiography for the guidance of percutaneous coronary intervention procedures to optimize outcomes. However, broader application of OCT has faced challenges, including subjective interpretation of the images and insufficient clinical outcome data. Future developments including artificial intelligence-assisted interpretation, multimodality catheters, and micro-OCT, as well as large prospective outcome studies could broaden the impact of OCT on cardiovascular medicine.

Clinical Significance of Coronary Healed Plaques in Stable Angina Pectoris Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND

Coronary healed plaques (HPs) reportedly have high vulnerability or show advanced atherosclerosis and a risk of rapid plaque progression. However, the prognosis of stable angina pectoris (SAP) patients with HPs undergoing percutaneous coronary intervention (PCI) remains under-investigated.Methods and Results: We analyzed 417 consecutive lesions from SAP patients undergoing pre- and post-intervention optical coherence tomography (OCT) for which HPs were defined as having a layered appearance. We investigated the differences in clinical and lesion characteristics, and post-PCI outcomes between HPs and non-HPs. To account for differences in clinical characteristics, propensity score matching was performed between the groups. HPs were observed in 216 lesions (51.8%) in the total cohort. In the propensity-matched cohort (n=294), HPs had higher rates of angiographic-B2/C lesions (77.6% vs. 59.2%, P<0.001), OCT-lipid-rich plaques (40.8% vs. 25.9%, P=0.007), macrophages (78.2% vs. 44.2%, P<0.001), greater luminal area stenosis (73.5±11.0% vs. 71.5±10.3%, P=0.002), and a higher prevalence of post-stenting irregular tissue protrusion (45.1% vs. 14.7%, P<0.001) than non-HPs. In the total cohort, target lesion revascularization (TLR)-free survival was poorer for HPs (log-rank test 7.66; P=0.006), and Cox proportional hazards analysis showed HP as an independent predictor of TLR (hazard ratio, 5.98; 95% confidence interval, 1.72-20.82; P=0.005).

CONCLUSIONS

In SAP patients, HPs had greater complexity of lesions and higher vulnerability, which may have contributed to the poorer post-PCI outcomes.

Feasibility of rotational atherectomy in patients with acute coronary syndrome: favorable in-hospital outcomes and clinical importance of complexed coronary atherosclerosis

The feasibility of rotational atherectomy (RA) during percutaneous coronary intervention (PCI) in patients who present with acute coronary syndrome (ACS) remains fully unsettled. We retrospectively evaluated 198 consecutive patients who underwent RA during PCI from 2009 to 2020. All patients underwent intracoronary imaging (intravascular ultrasound 96.5%, optical coherence tomography 9.1%, both 5.6%) during PCI. Patients who underwent RA during PCI were divided into two groups: ACS (n = 49; unstable angina pectoris, n = 27; non-ST-elevation myocardial infarction, n = 18, and ST-elevation myocardial infarction, n = 4) and chronic coronary syndrome (CCS) (n = 149). The RA procedural success rate was comparable between in the ACS and CCS groups (93.9 vs. 89.9%, P = 0.41). No significant differences were observed in procedural complications and in-hospital death between the groups. The incidence of major adverse cardiovascular event (MACE) after 2 years was significantly higher in ACS group compared with CCS group (38.7 vs. 17.4%, log-rank P = 0.002). Multivariable Cox regression analysis identified SYNTAX score or CABG SYNTAX score > 22 (hazard ratio (HR) 2.66, 95% confidence interval (CI) 1.40-5.06, P = 0.002) and mechanical circulatory support during the procedure (HR 2.61, 95% CI 1.21-5.59, P = 0.013) as predictors of MACE at 2 years, but not ACS on index admission (HR 1.58, 95% CI 0.84-2.99, P = 0.151). RA procedure is feasible as a bail-out strategy for ACS lesions. However, more complexed coronary atherosclerosis and mechanical circulatory support during RA procedure, but no ACS lesions were associated with worse mid-term clinical outcomes.

Calcium evaluation using coronary computed tomography in combination with optical coherence tomography

Optical coherence tomography (OCT) can assess calcium thickness, a key factor for predicting good stent expansion; however, it underestimates coronary calcium severity due to its penetration limitation. This study aimed to evaluate computed tomography (CT) and OCT images to assess calcification. We investigated 25 left anterior descending arteries of 25 patients, using coronary CT and OCT, and assessed their calcification. Of the 25 vessels, 1811 pairs of CT and OCT cross-sectional images were co-registered. Of the 1811 cross-sectional CT images, calcification was not detectable in 256 (14.1%) of the corresponding OCT images due to limited penetration. In the 1555 OCT calcium-detectable images, the maximum calcium thickness was not detectable in 763 (49.1%) images compared to the CT images. In CT images of slices corresponding to undetected calcium in OCT images, the angle, thickness, and maximum density of calcium were significantly smaller compared to slices corresponding to detected calcium in OCT. Calcium with an undetectable maximum thickness in the corresponding OCT image had a significantly greater calcium angle, thickness, and density than calcium with a detectable maximum thickness. There was an excellent correlation between CT and OCT with respect to calcium angle ( R= 0.82, P < 0.001). The calcium thickness on the OCT image had a stronger correlation with the maximum density on the corresponding CT image (R = 0.73, P < 0.001) than with the calcium thickness on the CT image (R = 0.61, P < 0.001). Cross-sectional CT imaging allows for pre-procedural assessment of calcium morphology and severity and could complement the lack of information on calcium severity in OCT-guided percutaneous coronary intervention.

The role of invasive and non-invasive imaging technologies and calcium modification therapies in the evaluation and management of coronary artery calcifications

The treatment of coronary artery disease (CAD) has advanced significantly in recent years due to improvements in medical therapy and percutaneous or surgical revascularization. However, a persistent obstacle in the percutaneous management of CAD is coronary artery calcification (CAC), which portends to higher rates of procedural challenges, post-intervention complications, and overall poor prognosis. With the advent of novel multimodality imaging technologies spanning from intravascular ultrasound to optical coherence tomography to coronary computed tomography angiography combined with advances in calcium debulking and modification techniques, CACs are now targets for intervention with growing success. This review will summarize the most recent developments in the diagnosis and characterization of CAC, offer a comparison of the aforementioned imaging technologies including which ones are most suitable for specific clinical presentations, and review the CAC modifying therapies currently available.

Use of intravascular optical coherence tomography to confirm the diagnosis of a carotid web in a patient with recurrent ipsilateral embolic strokes and evaluate the response to stenting

A Carotid web (CaW) is defined as a focal shelf-like projection of non-atheromatous, fibrous tissue along the posterior wall of the carotid bulb. CaW are rare and commonly overlooked lesions increasingly recognized as a cause of stroke in otherwise healthy patients. Intravascular imaging modalities such as intravascular ultrasound and optical coherence tomography (OCT) have been proposed as an adjunct to digital subtraction angiography for the evaluation of CaW. However, the use of OCT in CaW has yet to be described. This report investigated the utility of OCT as an adjunct imaging modality in the evaluation of CaW morphology in a young patient with recurrent ischemic strokes.

Mean density of computed tomography for predicting rotational atherectomy during percutaneous coronary intervention

BACKGROUND

Multi-slice computed tomography (CT) allows noninvasive evaluation of the severity of coronary calcification. However, there has yet to be a definitive parameter based on the cross-sectional CT image for predicting the need for rotational atherectomy (RA). Therefore, we aimed to investigate the mean density of cross-sectional CT images to predict the need for RA during percutaneous coronary intervention (PCI).

METHODS

A total of 154 lesions with moderate to severe calcification detected in coronary angiography were identified in 126 patients who underwent coronary CT prior to PCI for stable angina. PCI with RA was performed for 48 lesions, and the remaining 106 were treated without RA. Multi-slice CT was retrospectively evaluated for its ability to predict the use of RA. We chose the most severely calcified cross-sectional image for each lesion. The mean density within the outer vessel contour, calcium arc quadrant of the cross-sectional CT image, calcium length, calcification remodeling index, and per-lesion coronary artery calcium score was studied.

RESULTS

Receiver-operator characteristic curve analysis revealed 637 Hounsfield units (HU) (area under the curve ​= ​0.98, 95% confidence interval: 0.97-1.00, p ​< ​0.001) as the best mean density cutoff value for predicting RA. Multivariate logistic regression analysis showed that a mean calcium level >637 HU was a strong independent predictor (odds ratio: 32.8, 95% confidence interval: 7.0-153, p ​< ​0.001) for using RA.

CONCLUSIONS

The mean density of the cross-sectional CT image, a simple quantitative parameter, was the strongest predictor of the need for RA during PCI.

Prediction of optical coherence tomography-detected calcified nodules using coronary computed tomography angiography

Diagnosis of calcified nodules (CNs) is critical in the proper management of coronary artery disease, but CNs can be detected only using intracoronary imaging modalities. This study aimed to investigate the ability of coronary computed tomography angiography (CCTA) in predicting CNs detected using optical coherence tomography (OCT). From 138 patients who underwent OCT-guided percutaneous coronary intervention (PCI) after CCTA evaluation, 141 PCI target vessels were retrospectively enrolled and classified into CN (12 vessels/11 patients; CNs in the PCI culprit lesion) and non-CN (129 vessels/127 patients; without CNs) groups based on the OCT analysis. Retrospective CCTA analysis revealed significantly higher coronary artery calcification score (CACS), calcified plaque volume (CPV), and maximum calcified plaque area (MCPA) of the target vessel in the CN group than in the non-CN group. Receiver operating characteristic curve indicated that CACS ≥ 162 (area under the ROC curve (AUC 0.76, sensitivity 83.3%, specificity 54.2%), CPV ≥ 20.1 mm³ (AUC 0.83, sensitivity 100%, specificity 57.3%), and MCPA ≥ 4.51 mm² (AUC 0.87, sensitivity 91.7%, specificity 78.3%) were the best cutoff values for predicting CNs. MCPA showed the highest AUC among all the CCTA parameters. In conclusion, CCTA is useful for predicting OCT-detected CNs in PCI target vessels.

[Invasive and non-invasive imaging analysis for calcified coronary artery lesions]

Coronary calcifications are frequently identified within coronary lesions as their incidence increases with age and cardiovascular risk factors. Their location can be superficial or deep, according to different pathological process. In all cases, the presence of calcifications within the vascular wall predicts poor clinical prognosis and unfavorable evolution after percutaneous revascularization. Coronary calcifications can be analyzed by angiography, CT or intracoronary imaging (IVUS or OCT) with variable accuracies. Angiography is the most frequently used method but is not very sensitive (sensitivity close to 50%) and insufficient for their precise quantification. The CT scan is a more effective non-invasive method leading to an accurate analysis of the lesion before coronary angiography. IVUS and OCT have an excellent spatial resolution and are the most sensitive methods for the identification (present in nearly 75-80% of lesions) and quantification of calcifications. These intracoronary imaging techniques offer interesting perspectives for identification of the highest-risk lesions, PCI procedures planning (including the choice of an optimal dedicated plaque preparation devices), the monitoring of their execution and the evaluation of the immediate post-stenting results.

Optical coherence tomography in coronary atherosclerosis assessment and intervention

Since optical coherence tomography (OCT) was first performed in humans two decades ago, this imaging modality has been widely adopted in research on coronary atherosclerosis and adopted clinically for the optimization of percutaneous coronary intervention. In the past 10 years, substantial advances have been made in the understanding of in vivo vascular biology using OCT. Identification by OCT of culprit plaque pathology could potentially lead to a major shift in the management of patients with acute coronary syndromes. Detection by OCT of healed coronary plaque has been important in our understanding of the mechanisms involved in plaque destabilization and healing with the rapid progression of atherosclerosis. Accurate detection by OCT of sequelae from percutaneous coronary interventions that might be missed by angiography could improve clinical outcomes. In addition, OCT has become an essential diagnostic modality for myocardial infarction with non-obstructive coronary arteries. Insight into neoatherosclerosis from OCT could improve our understanding of the mechanisms of very late stent thrombosis. The appropriate use of OCT depends on accurate interpretation and understanding of the clinical significance of OCT findings. In this Review, we summarize the state of the art in cardiac OCT and facilitate the uniform use of this modality in coronary atherosclerosis. Contributions have been made by clinicians and investigators worldwide with extensive experience in OCT, with the aim that this document will serve as a standard reference for future research and clinical application.

Effect of C1q/TNF-Related Protein 9 on Coronary Artery Calcification: An Observational Study

Coronary artery calcification (CAC) increases the risk of acute coronary syndrome. This study examined the correlation between C1q/TNF-related protein 9 (CTRP9) and CAC and explored CTRP9 as a biomarker for prognosis. We divided 275 patients with coronary heart disease into four groups. In order to balance the baseline confounding factors, propensity score matching (PSM) was performed to match CAC patients with non-CAC patients in a 1:1 ratio. Optical coherence tomography (OCT) calcification scoring was performed in 126 patients with CAC. Moreover, 140 patients who underwent OCT were followed-up for 9 months for analysis of the correlation between CTRP9 levels and clinical prognosis. Based on OCT calcification scores, 126 patients with CAC were divided into the 0–2 and 3–4 groups. Plasma CTRP9 levels were significantly lower in the type 2 diabetes mellitus (T2DM), CAC and CAC with T2DM groups than in the control group. CTRP9 played roles as a protective factor and potential predictor in CAC severity. The AUC of the OCT calcification score 3–4 group predicted by the plasma CTRP9 level was 0.766. During the follow-up period, the cumulative event-free survival rate was significantly lower in the low-level CTRP9 (L-CTRP9) group than in the high-level (H-CTRP9) group, and the incidence of major endpoint events was significantly higher in the L-CTRP9 group than in the H-CTRP9 group. CTRP9 can be a valuable biomarker for CAC occurrence and severity and can predict patients’ clinical prognosis.

Detection of myocardial bridge by optical coherence tomography

Myocardial bridge (MB) is less commonly documented by angiography than autopsy. Optical coherence tomography (OCT) may be useful to detect angiographically undetectable MB. To investigate OCT characteristics of MB, 86 LAD vessels were imaged by OCT. MB was defined as presence of intermediate optical intensity, "fine" layer surrounding coronary artery by OCT. Frequency and characteristics of the angio-detectable and angio-undetectable but OCT-detectable MB were investigated. In a subset of patients with angio-detectable MB, cyclic changes in coronary arterial dimensions were analyzed. OCT detected MB in 44 of 86 (51%). Arc of the MB was significantly larger (334.8 ± 58.5° vs. 268.4 ± 92.1°, P = 0.008) and length was significantly longer (22.6 ± 11.7 mm vs. 14.5 ± 8.1 mm, P = 0.014) in angio-detectable MB than OCT-detectable but angio-undetectable MB. Both vessel (6.8 ± 1.5 to 5.3 ± 1.0 mm2, P = 0.035) and lumen area (4.4 ± 1.5 to 3.1 ± 0.7 mm2, P = 0.040) decreased significantly from diastole to systole. Adventitial (0.08 ± 0.03 to 0.08 ± 0.02 mm, P = 0.828) and intima + plaque thickness (0.12 ± 0.05 to 0.10 ± 0.03 mm, P = 0.398) did not change significantly during cardiac cycle. On the other hand, medial thickness increased significantly from diastole to systole (0.08 ± 0.03 to 0.12 ± 0.03 mm, P = 0.022). In conclusion, MB is frequently detected as intermediate intensity, fine layer by OCT. During systole, vessel and lumen size decrease with increased medial thickness. Therefore, we should be careful for OCT interpretation of the coronary arteries with MB.

Incidence and prognostic impact of the calcified nodule in coronary artery disease patients with end-stage renal disease on dialysis

Coronary artery calcification is frequently observed in coronary artery disease (CAD) patients with end-stage renal disease (ESRD). Calcified nodule (CN) is recognized as one of the vulnerable plaque characteristics responsible for acute coronary syndrome (ACS). Although CN is a cause of ACS in only 10%, its prevalence may be higher in elderly patients and/or ESRD. The aim of this study is to investigate incidence, clinical characteristics, and prognostic impact of CN in CAD patients with ESRD on dialysis. A total of 51 vessels from 49 CAD patients with ESRD on dialysis were enrolled in this study. CN was defined as a high-backscattering mass protruding into the lumen with a strong signal attenuation and an irregular surface by optical coherence tomography. Incidence, clinical characteristics and prognosis of patients with CN were studied. Major adverse cardiac events (MACE) were defined as a composite of all-cause death, non-fatal myocardial infarction, target vessel revascularization (TVR) and stroke. CNs were observed in 30 vessels from 29 patients (59.2%). Duration of dialysis was significantly longer in CN group than in non-CN group (P = 0.03). Overall, all-cause death, cardiac death, TVR and MACE occurred in 7 (14.3%), 3 (6.1%), 11 (22.4%) and 16 (32.7%) patients during follow-up (median 826 days), respectively. Kaplan-Meier survival analysis revealed that MACE-free survival was significantly lower in patients with CN compared with those without CN (Log-rank, P = 0.036).In conclusion, CN was observed in about 60% of the CAD patients with ESRD and was associated with duration of dialysis and worse prognosis.

Impact of nodular calcification in patients with acute coronary syndrome (ACS) treated with primary percutaneous coronary intervention (PCI)

BACKGROUND

Calcified plaque is thought to adversely impact outcomes after percutaneous coronary intervention (PCI). This study sought to evaluate the impact of nodular calcification in patients with acute coronary syndrome treated with primary percutaneous coronary intervention.

METHODS

Using optical coherence tomography (OCT), 500 culprit plaques with calcification were analyzed from 495 acute coronary syndrome (ACS) patients on whom PCI was performed. Based on morphology, we classified calcification into two subtypes: nodular calcification and non-nodular calcification. Nodular calcification was defined as protruding mass with an irregular surface, high backscattering, and signal attenuation while non-nodular calcification was defined as an area with low backscattering heterogeneous region with a well-delineated border without protrusion into the lumen on OCT.

RESULTS

Calcified culprit plaques were divided into nodular calcification group (n = 238) and non-nodular calcification group (n = 262). Patients with nodular calcification were older (p < 0.001) and had lower left ventricular ejection fraction (p = 0.006) compared to patients with non-nodular calcification. Minimum stent area (5.0 (3.9, 6.3) mm² vs. 5.4 (4.2, 6.7) mm², p = 0.011) and stent expansion (70 (62.7, 81.8) % vs. 75 (65.2, 86.6) %, p = 0.004) were significantly smaller in the nodular calcification group than in the non-nodular calcification group. Stent under-expansion was most frequent (p = 0.003) in the nodular calcification group.

CONCLUSION

This study demonstrate that the presence of nodular calcification is associated with a smaller minimum stent area and a higher incidence of stent under-expansion. Lesions with nodular calcification may be at risk of stent under-expansion.

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

A previous calcium scoring system using circumferential angle, thickness, and length of coronary calcium by OCT could assist in predicting stent under-expansion. However, this scoring system only reflects the calcification distribution within a single cross-section and fails to consider the lumen's original size. The current study aims to investigate whether novel parameters to quantify calcium lesions, including calcium burden, area, and volume assessed by optical coherence tomography (OCT), could predict stent under-expansion related to calcium lesions. Consecutive patients admitted between March 10th to October 19th 2021 with calcified coronary lesions undergoing percutaneous coronary intervention (PCI) with OCT guidance were screened for inclusion. The calcium burden, area, and volume of the target lesions were measured using OCT at pre-PCI. After successful stent implantation, stent expansion at the corresponding lesions was also measured by OCT. A total of 125 patients who underwent OCT-guided PCI were included in this study. While the calcium grades by angiography failed to show a significant correlation with stent expansion, maximum and average calcium burden, maximum calcium area, and calcium volume exhibited a moderate correlation with stent expansion. According to the receiver operating characteristic curves, the optimal cutoffs of calcium volume and area for predicting stent under-expansion were 4.37 mm³ and 2.48 mm² , respectively. Calcium burden, area, and volume by OCT are more favorable predictors of stent under-expansion given its better performance than calcium grades by angiography. Using cutoffs of calcium area and volume could identify high-risk patients of under-expansion and might guide future clinical practice.

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.

Calcium Modification Therapies in Contemporary Percutaneous Coronary Intervention

Coronary Artery Calcification (CAC) has been known to be associated with worse Percutaneous Coronary Intervention (PCI) short- and long-term outcomes. Nowadays, with the increased prevalence of the risk factors leading to CAC in the population and also more PCI procedures done in older patients and with the growing number of higher-risk cases of Chronic Total Occlusion (CTO) PCI and PCI after Coronary Artery Bypass Grafting (CABG), severe cases of CAC are now encountered on a daily basis in the catheterization lab and remain a big challenge to the interventional community, making it crucial to identify cases of severe CAC and plan a CAC PCI modification strategy upfront. Improved CAC detection with intravascular imaging helped identify more of these severe CAC cases and predict response to therapy and stent expansion based on CAC distribution in the vessel. Multiple available therapies for CAC modification have evolved over the years. Familiarity with the specifics and special considerations and limitations of each of these tools are essential in the choice and application of these therapies when used in severe CAC treatment. In this review, we discuss CAC pathophysiology, modes of detection, and different available therapies for CAC modification.

Prognostic Impact of Calcified Plaque Morphology After Drug Eluting Stent Implantation - An Optical Coherence Tomography Study

BACKGROUND

Optical coherence tomography (OCT) has the potential to characterize the detailed morphology of calcified coronary plaques. This study examined the prognostic impact of calcified plaque morphology in patients with coronary artery calcification (CAC) who underwent newer-generation drug-eluting stent (DES) implantation.Methods and Results:In all, 251 patients with moderate to severe CAC who underwent OCT-guided DES implantation were reviewed retrospectively and divided into 3 groups according to OCT findings of the target lesion: 25 patients (10.0%) with calcified nodules (CN), 69 patients (27.5%) with calcified protrusion (CP) without CN, and 157 patients (62.5%) with superficial calcific sheet (SC) without CN and CP. The primary endpoint was major adverse cardiac events (MACE), defined as a composite of cardiac death, myocardial infarction, and target lesion revascularization (TLR). Kaplan-Meier survival analysis revealed that, among the 3 groups, the rates of MACE-free survival (log-rank test, P=0.0117), myocardial infarction (log-rank test, P=0.0103), and TLR (log-rank test, P=0.0455) were significantly worse in patients with CN. Multivariate Cox proportional hazards analysis demonstrated that CN was an independent predictor of MACE (hazard ratio 4.41; 95% confidence interval 1.63-10.8; P=0.0047).

CONCLUSIONS

Target lesion CN was associated with higher cardiac event rates in patients who underwent newer-generation DES implantation for lesions with moderate to severe CAC.

Acute coronary syndrome demonstrating plaque rupture in calcified plaque visualized by optical coherence tomography and near-infrared spectroscopy combined with intravascular ultrasound

Optical coherence tomography (OCT) can visualize calcification of the coronary plaque as a low-intensity lesion with sharp borders. However, residual lipid tissue inside the calcification could pose a problem in plaque evaluation by OCT. We present a case of acute coronary syndrome (ACS) demonstrating plaque rupture in the calcified plaque. In this case, OCT demonstrated a cavity suspected to represent rupture in the calcified plaque and near-infrared spectroscopy revealed a lipid component behind the calcified plaque. Although calcified plaque is not considered a reason for ACS except for calcified nodules, residual lipid tissue inside the calcification might cause ACS if the thin fibrous cap over the lipid tissue is disrupted, even if surrounded by calcification. <Learning objective: This is the first case report to describe plaque rupture in calcified plaque visualized by OCT and near-infrared spectroscopy. Lipid tissue surrounded by calcification is generally recognized as calcified plaque on OCT because discrimination between lipid tissue and calcification is based on border characteristics. Residual lipid tissue within calcification could pose a problem in plaque evaluation by OCT.>.

Contemporary technologies to modify calcified plaque in coronary artery disease

With aging society, one of the more challenging obstacles in percutaneous coronary interventions are calcified coronary lesions. Calcified lesions may impede stent delivery, limit balloon and stent expansion, cause uneven drug distribution, and hinder wire advancement. Even in the setting of acceptable procedural success, vessel calcification is independently associated with increased target lesion revascularization rates at follow-up and lower survival rates. In order to effectively manage such lesions, dedicated technologies have been developed. Atherectomy aims at excising tissue and debulking plaques, as well as compressing and reshaping the atheroma, generally referred to as lesion preparation that enables further balloon and/or stent expansion in contemporary clinical practice. In the current review, we will discuss the available methods for atherectomy, including rotational, orbital, and excimer laser coronary atherectomy, as well as intravascular lithotripsy. In addition, we will review the role of imaging in calcified lesions.

Comparison of optical coherence tomography-guided and intravascular ultrasound-guided rotational atherectomy for calcified coronary lesions

Background

To compare the effect and outcomes of optical coherence tomography (OCT)-guided rotational atherectomy (RA) with intravascular ultrasound (IVUS)-guided RA in the treatment of calcified coronary lesions.

Methods

Data of calcified coronary lesions treated with RA that underwent OCT-guided or IVUS-guided from January 2016 to December 2019 at a single-center registry were retrospectively analyzed. The effect and outcomes between underwent OCT-guided RA and IVUS-guided RA were compared.

Results

A total of 33 lesions in 32 patients received OCT-guided RA and 51 lesions in 47 patients received IVUS-guided RA. There was no significant difference between OCT-guided RA group and IVUS-guided RA group in clinical baselines characteristics. Comparing the procedural and lesions characteristics of the two groups, the contrast volume was larger [(348.8 ± 110.6) ml vs. (275.2 ± 76.8) ml, P = 0.002] and the scoring balloon was more frequently performed (33.3% vs. 3.9%, P = 0.001) after RA and before stenting in the OCT-guided RA group. Comparing the intravascular imaging findings of the two groups, stent expansion was significantly larger in the OCT-guided RA group ([82 ± 8]% vs. [75 ± 9]%, P = 0.001). Both groups achieved procedural success immediately. There were no significantly differences in the incidence of complications. Although there was no statistical difference in the occurrence of MACE at 1 year between OCT-guided RA group and IVUS-guided RA group (3.1% vs. 6.4%, P = 0.517), no cardiovascular death, TVR and stent thrombosis occurred in OCT-guided RA group.

Conclusions

OCT-guided RA compared to IVUS-guided RA for treating calcified coronary lesions resulted in better stent expansion and may have improved prognosis.

Optical coherence tomography-versus intravascular ultrasound-guided stent expansion in calcified lesions

Optical coherence tomography (OCT) has a higher resolution than intravascular ultrasound (IVUS) and enables a more precise evaluation of calcium severity. We investigated the impact of the imaging method (OCT versus IVUS) on stent expansion during intravascular imaging-guided percutaneous coronary intervention (PCI) in calcified lesions. In this single-center, retrospective, observational study, 145 lesions with moderate to severe calcification were divided into four groups: 40 IVUS-guided rotational atherectomy (RA), 38 IVUS-guided non-RA, 35 OCT-guided RA, and 32 OCT-guided non-RA. Lesions without pre-procedural intravascular imaging were excluded. OCT-guided RA was associated with greater stent expansion at the target calcium compared with IVUS-guided RA (median 88.0%, interquartile range [78.0-96.0] vs. 76.5% [71.0-84.3], P = 0.008). Furthermore, stent expansion in OCT-guided non-RA was similar to OCT-guided RA. OCT-guided RA used a larger burr compared to IVUS-guided RA (1.75 mm [1.50-2.0] vs. 1.50 mm [1.50-1.75], P = 0.004). In OCT-guided RA, the median minimum calcium thickness was significantly reduced from 800 (640-980) µm to 550 (350-680) µm (P < 0.001). There was no significant difference in the incidence of ischemia driven target lesion revascularization between the four groups (P = 0.37). By determining the indication and endpoint of lesion modification by RA based on the thickness of calcium, OCT-guided PCI was associated with significantly greater stent expansion compared with IVUS-guided PCI.

Management of calcified coronary artery bifurcation lesions

Calcified coronary artery bifurcation lesions (CBL) remain a challenge for the interventional cardiologist. Evidence regarding treatment of CBL is minimal. Optimal plaque modification is the most important step prior to stent deployment. Provisional stenting is the preferred strategy for most bifurcation lesions. However, two-stent strategy should be considered for BL with compromised large SB (>2.5 mm) supplying a large territory, >70% SB stenosis and lesions more than 5 mm long. In this contemporary review article, we present a simplified approach to treating CBL and demonstrate the approach to specific case examples using our newly developed mobile application, BifurcAID.

Prediction of the debulking effect of rotational atherectomy using optical frequency domain imaging

Whether predicting the rotational atherectomy (RA) effect based on the position of optical frequency domain imaging (OFDI) is accurate remains uncertain. The aim of this study was to evaluate the predictive accuracy of OFDI in identifying RA location and area. Twenty-five patients who underwent RA with OFDI were included. On pre-RA OFDI images, a circle with the dimension of a Rota burr was drawn at the center of the OFDI catheter. The area where the circle overlapped with the vessel wall was defined as the predicted ablation area (P-area), and the actual ablated area (A-area) was measured. The predictive accuracy of OFDI was evaluated as follows: overlapped ablation area (O-area: overlapping P- and A-areas) divided by P-area = %Correct-area, and A-area - O-area divided by A-area = %Error-area. Cross-sections were separated into four categories based on the median values of %Correct- and %Error-area. Among 334 cross-sections, RA effects were confirmed in the predicted location in 87% of them. The median %Correct- and %Error-areas were 43.1% and 64.2%, respectively. Floppy wire, narrow lumen area, OFDI catheter close to the intima, and large arc of calcium were independently associated with good prediction (high %Correct-/low %Error-areas). Non-left anterior descending lesions, OFDI catheter far from the wire, and OFDI catheter and wire far from the intima were associated with irrelevant ablation (low %Correct-/ high %Error-areas). The accuracy of the OFDI-based predictions for RA effects was acceptable with regard to location, but not high with regard to area. Wire types, target vessels, and OFDI catheter and wire positions are important determinants for accurately predicting RA effect using pre-procedural OFDI.

Coronary artery disease prediction based on breast arterial calcification in women undergoing mammography as a screening for breast cancer

OBJECTIVE

The aim of the study was to test the potential role of breast arterial calcification (BAC) in the prediction of coronary artery disease (CAD) in women. The criterion standard for CAD diagnostics was coronary angiography.

METHODS

This retrospective study enrolled 163 consecutive women, who underwent digital mammography and coronary angiography in our hospital. We assessed the presence and severity of BAC, and tested whether the presence and/or extent of BAC could be a predictor for CAD, quantified by Gensini score.

RESULTS

BAC was presented in 34 patients (21%). Neither the presence of CAD (17 patients, 50%, vs 55 42.6%, P = 0.44), nor the Gensini score (20.5 ± 29.7 vs 15.4 ± 24.1, P = 0.3) differed significantly between BAC-present and BAC-absent patients.A finding of triple-vessel disease, however, more frequently occurred in the BAC-present (seven patients, 20.6%) than in the BAC-absent (nine patients, 7%) group, odds ratio (OR) 3.1, 95% CI 1-9.5, P = 0.049. The presence of BAC did not significantly increase the odds for the presence of CAD (OR = 1.29, P = 0.54). Among the subgroup of patients with CAD, BAC presence was associated with triple vessel disease (OR = 3.34, P = 0.049).

CONCLUSIONS

We did not confirm BAC as a predictor of CAD. However, BAC showed association with more severe forms of coronary atherosclerosis (triple vessel disease).

Multi-modality intravascular imaging for guiding coronary intervention and assessing coronary atheroma: the Novasight Hybrid IVUS-OCT system

Intravascular imaging has evolved alongside interventional cardiology as an adjunctive tool for assessing plaque pathology and for guiding and optimising percutaneous coronary intervention (PCI) in challenging lesions. The two modalities which have dominated the field are intravascular ultrasound (IVUS), which relies on sound waves and optical coherence tomography (OCT), relying on light waves. These approaches however have limited efficacy in assessing plaque morphology and vulnerability that are essential for guiding PCI in complex lesions and identifying patient at risk that will benefit from emerging therapies targeting plaque evolution. These limitations are complementary and, in this context, it has been recognised and demonstrated in multi-modality studies that the concurrent use of IVUS and OCT can help overcome these deficits enabling a more complete and accurate plaque assessment. The Conavi Novasight Hybrid IVUS-OCT catheter is the first commercially available device that is capable of invasive clinical coronary assessment with simultaneously acquired and co-registered IVUS and OCT imaging. It represents a significant evolution in the field and is expected to have broad application in clinical practice and research. In this review article we present the limitations of standalone intravascular imaging techniques, summarise the data supporting the value of multimodality imaging in clinical practice and research, describe the Novasight Hybrid IVUS-OCT system and highlight the potential utility of this technology in coronary intervention and in the study of atherosclerosis.

New interventional solutions in calcific coronary atherosclerosis: drill, laser, shock waves

In the percutaneous treatment of coronary stenoses, it is essential to take into account the presence of calcifications as this influences the short- and long-term post-procedural outcomes. Today in the catheterization laboratory, there are several tools for the treatment of calcium; exploiting the different operating mechanisms, possibly even combining them together, is part of a modern approach to coronary angioplasty that aims to optimize results. To this end, each procedure must be properly planned and, in this perspective, intracoronary imaging (such as optical coherence tomography and intravascular ultrasound) is an essential aid to guide the procedure and show results.

Predictors for Rapid Progression of Coronary Calcification: An Optical Coherence Tomography Study

Background The role of coronary calcification in cardiovascular events and plaque stabilization is still being debated, and factors involved in the progression of coronary calcification are not fully understood. This study aimed to identify the predictors for rapid progression of coronary calcification. Methods and Results Patients with serial optical coherence tomography imaging at baseline and at 6 months were selected. Changes in the calcification index and predictors for progression of calcification were studied. Calcification index was defined as the product of the mean calcification arc and calcification length. Rapid progression of calcification was defined as an increase in the calcification index above the median value. Among 187 patients who had serial optical coherence tomography imaging, 235 calcified plaques were identified in 105 patients (56.1%) at baseline. After 6 months, the calcification index increased in 95.3% of calcified plaques from 132.0 to 178.2 (P<0.001). In multivariable analysis, diabetes mellitus (odds ratio [OR], 3.911; P<0.001), chronic kidney disease (OR, 2.432; P=0.037), lipid-rich plaque (OR, 2.698; P=0.034), and macrophages (OR, 6.782; P<0.001) were found to be independent predictors for rapid progression of coronary calcification. Interestingly, rapid progression of calcification was associated with a significant reduction of inflammatory features (thin-cap fibroatheroma; from 21.2% to 11.9%, P=0.003; macrophages; from 74.6% to 61.0%, P=0.001). Conclusions Diabetes mellitus, chronic kidney disease, lipid-rich plaque, and macrophages were independent predictors for rapid progression of coronary calcification. Baseline vascular inflammation and subsequent stabilization may be related to rapid progression of calcification. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT01110538.

Calcium Modification Techniques in Complex Percutaneous Coronary Intervention

Percutaneous coronary intervention is the most common mode of revascularization and is increasingly undertaken in high-risk subsets, including the elderly. The presence of coronary artery calcification is increasingly observed and significantly limits technical success. The mechanisms for this are multi-factorial, including increased arterial wall stiffness and impaired delivery of devices, leading to suboptimal stent delivery, deployment, and expansion which are harbingers for increased risk of in-stent restenosis and stent thrombosis. Although conventional balloon pretreatment techniques aim to mitigate this risk by modifying the lesion before stent placement, many lesions remain resistant to conventional strategies, due to the severity of calcification. There have been several substantial technological advancements in calcium modification methods in recent years, which have allowed improved procedural success with low periprocedural complication rates. This review will summarize the current adjunctive modification technologies that can be employed to improve technical outcomes in percutaneous coronary intervention in calcific disease and the evidence supporting these tools.

Epidemiological Research Advances in Vascular Calcification in Diabetes

Vascular calcification is the transformation of arterial wall mesenchymal cells, particularly smooth muscle cells (SMCs), into osteoblast phenotypes by various pathological factors. Additionally, vascular transformation mediates the abnormal deposition of calcium salts in the vascular wall, such as intimal and media calcification. Various pathological types have been described, such as calcification and valve calcification. The incidence of vascular calcification in patients with diabetes is much higher than that in nondiabetic patients, representing a critical cause of cardiovascular events in patients with diabetes. Because basic research on the clinical transformation of vascular calcification has yet to be conducted, this study systematically expounds on the risk factors for vascular calcification, vascular bed differences, sex differences, ethnic differences, diagnosis, severity assessments, and treatments to facilitate the identification of a new entry point for basic research and subsequent clinical transformation regarding vascular calcification and corresponding clinical evaluation strategies.

Orbital-Tripsy: Novel Combination of Orbital-Atherectomy and Intravascular-Lithotripsy, in Calcified Coronaries After Failed Intravascular-Lithotripsy

Calcified coronary lesions are notorious for posing technical difficulty during angioplasty. Fortunately, more devices are available to tackle coronary calcifications. However, there remain difficult cases whereby a single modality is insufficient. Here we report the feasibility and success of a case, using Novo combination of Shockwave Lithotripsy after Orbital Atherectomy. (Level of Difficulty: Intermediate.).

Automated classification of coronary plaque calcification in OCT pullbacks with 3D deep neural networks

SIGNIFICANCE

Detection and characterization of coronary atherosclerotic plaques often need reviews of a large number of optical coherence tomography (OCT) imaging slices to make a clinical decision. However, it is a challenge to manually review all the slices and consider the interrelationship between adjacent slices.

APPROACH

Inspired by the recent success of deep convolutional network on the classification of medical images, we proposed a ResNet-3D network for classification of coronary plaque calcification in OCT pullbacks. The ResNet-3D network was initialized with a trained ResNet-50 network and a three-dimensional convolution filter filled with zeros padding and non-zeros padding with a convolutional filter. To retrain ResNet-50, we used a dataset of ∼4860 OCT images, derived by 18 entire pullbacks from different patients. In addition, we investigated a two-phase training method to address the data imbalance. For an improved performance, we evaluated different input sizes for the ResNet-3D network, such as 3, 5, and 7 OCT slices. Furthermore, we integrated all ResNet-3D results by majority voting.

RESULTS

A comparative analysis proved the effectiveness of the proposed ResNet-3D networks against ResNet-2D network in the OCT dataset. The classification performance (F1-scores  =  94  %   for non-zeros padding and F1-score  =  96  %   for zeros padding) demonstrated the potential of convolutional neural networks (CNNs) in classifying plaque calcification.

CONCLUSIONS

This work may provide a foundation for further work in extending the CNN to voxel segmentation, which may lead to a supportive diagnostic tool for assessment of coronary plaque vulnerability.

Management of Calcific Coronary Artery Lesions: Is it Time to Change Our Interventional Therapeutic Approach?

Patients with obstructive coronary lesions with a high calcium content (LHCC) have an exaggerated clinical risk, because the presence of calcification is associated with more extensive coronary atheroma and higher burden of comorbidities. Treatment of LHCC using percutaneous techniques is complex because of an increased risk of incomplete lesion preparation with suboptimal stent deployment and higher rates of acute and chronic stent failure. Rotational atherectomy has been the predominant technology for treatment of high-grade LHCC, but novel devices/technologies have entered clinical practice. It seems likely that combining enhanced intravascular imaging, which allows definition of the patterns of calcification with these new technologies, will herald a change in procedural algorithms for treatment of LHCC. This review provides an overview about LHCC with special focus on existing and emergent technologies. We also provide a proposed procedural algorithm to facilitate optimal use of technology according to specific features of LHCC and coronary anatomy.

Optical coherence tomography-guided versus intravascular ultrasound-guided rotational atherectomy in patients with calcified coronary lesions

AIMS

We aimed to evaluate whether optical coherence tomography (OCT)-guided rotational atherectomy (RA) improves stent expansion and clinical outcomes compared to intravascular ultrasound (IVUS)-guided RA.

METHODS AND RESULTS

From our database, we identified 247 de novo calcified coronary lesions that underwent RA between September 2013 and December 2017. Of these, lesions with no intravascular imaging data (n=11), poor image quality (n=7), balloon angioplasty alone (n=16), and complications (two burr entrapments, two perforations) were excluded. Finally, 88 and 121 lesions that underwent OCT-guided and IVUS-guided RA, respectively, were included in the study. The primary endpoint of the present study was percent stent expansion. Burr upsizing was more frequently performed (55% vs 32%, p=0.001) and the final burr size was significantly larger (1.75 [1.50-1.75] vs 1.50 [1.50-1.75] mm, p<0.001) in the OCT-guided RA group. Percent stent expansion was significantly larger in the OCT-guided RA group (83±15% vs 72±16%, p=0.0004). Although TLR at one year was lower in the OCT-guided RA group, there was no statistical difference (6.8% vs 11.6%, p=0.25).

CONCLUSIONS

OCT-guided RA for calcified coronary lesions resulted in larger percent stent expansion compared to IVUS-guided RA. OCT-guided RA may be ideal for treating calcified coronary lesions.

CD4+/CD8+ ratio positively correlates with coronary plaque instability in unstable angina pectoris patients but fails to predict major adverse cardiovascular events

Background:

The association between CD4+/CD8+ ratio and coronary plaque instability in patients with unstable angina pectoris (UAP) has not been investigated. We sought to elucidate the correlation between CD4+/CD8+ ratio and plaque instability in this patient population.

Methods:

We enrolled 266 UAP patients who underwent pre-intervention optical coherence tomography (OCT) examination and percutaneous coronary intervention in our center from January 2016 to January 2018. Features of coronary plaques in the culprit arteries were classified as unstable plaque and stable plaque. Primary endpoint was occurrence of a major adverse cardiovascular event (MACE). Receiver operating characteristic (ROC) analyses were used to determine the predictive efficacy of the CD4+/CD8+ ratio for a group of unstable plaque patients, and binary logistic regression analysis was performed to evaluate potential independent predictors of plaque instability. All-cause mortality and MACE between the two groups were analyzed.

Results:

UAP patients with unstable plaque had a higher CD4/CD8 ratio compared with stable plaque patients (p < 0.05). Results of binary logistic regression analyses showed that CD4+/CD8+ ratio ⩾1.725 and prior stroke were predictors and risk factors of plaque instability (p < 0.05). ROC analyses showed that CD4+/CD8+ ratio ⩾1.725 was predictive of plaque instability in UAP patients. However, the Kaplan–Meier estimate for MACE and all-cause mortality showed no statistical significance.

Conclusions:

Higher CD4+/CD8+ ratio is associated with higher risk of plaque instability in our cohort of UAP patients. However, CD4+/CD8+ ratio was not an independent predictor of 1-year MACE or all-cause mortality.

An optical coherence tomography comparison of coronary arterial plaque calcification in patients with end-stage renal disease and diabetes mellitus

BACKGROUND

Coronary arterial plaques in patients with end-stage renal disease (ESRD) are assumed to have increased calcification due to underlying renal disease or initiation of dialysis. This relationship may be confounded by comorbid type 2 diabetes mellitus (DM).

METHODS

From a single-center OCT registry, 60 patients were analyzed. Twenty patients with ESRD and diabetes (ESRD-DM) were compared to 2 groups of non-ESRD patients: 20 with and 20 without diabetes. In each patient, one 20 mm segment within the culprit vessel was analyzed.

RESULTS

ESRD-DM patients exhibited similar calcium burden, arc, and area compared to patients with diabetes alone. When compared to patients without diabetes, patients with diabetes exhibited a greater summed area of calcium (DM: Median 9.0, IQR [5.3-28] mm2 vs Non-DM: 3.5 [0.1-14] mm2, p = 0.04) and larger calcium deposits by arc (DM: Mean 45 ± SE 6.2° vs Non-DM: 21 ± 6.2°, p = 0.01) and area (DM: 0.58 ± 0.10 mm2 vs Non-DM: 0.26 ± 0.10 mm2, p = 0.03). Calcification deposits in ESRD-DM patients (0.14 ± 0.02 mm) and patients with diabetes (0.14 ± 0.02 mm) were more superficially located relative to patients without diabetes (0.21 ± 0.02 mm), p = 0.01 for both.

CONCLUSIONS

Coronary calcification in DM and ESRD-DM groups exhibited similar burden, deposit size, and depth within the arterial wall. The increase in coronary calcification and cardiovascular disease events seen in ESRD-DM patients may not be secondary to ESRD and dialysis, but instead due to a combination of declining renal function and diabetes.

Optical Coherence Tomography-Based Modeling of Stent Deployment in Heavily Calcified Coronary Lesion

In this work, a heavily calcified coronary artery model was reconstructed from optical coherence tomography (OCT) images to investigate the impact of calcification characteristics on stenting outcomes. The calcification was quantified at various cross sections in terms of angle, maximum thickness, and area. The stent deployment procedure, including the crimping, expansion, and recoil, was implemented. The influence of calcification characteristics on stent expansion, malapposition, and lesion mechanics was characterized. Results have shown that the minimal lumen area following stenting occurred at the cross section with the greatest calcification angle. The calcification angle constricted the stretchability of the lesion and thus resulted in a small lumen area. The maximum principal strain and von Mises stress distribution patterns in both the fibrotic tissue and artery were consistent with the calcification profiles. The radially projected region of the calcification tends to have less strain and stress. The peak strain and stress of the fibrotic tissue occurred near the interface with the calcification. It is also the region with a high risk of tissue dissection and strut malapposition. In addition, the superficial calcification with a large angle aggregated the malapposition at the middle of the calcification arc. These detailed mechanistic quantifications could be used to provide a fundamental understanding of the role of calcification in stent expansions, as well as to exploit their potential for enhanced pre- and post-stenting strategies.

Effect of cutting balloon after rotational atherectomy in severely calcified coronary artery lesions as assessed by optical coherence tomography

OBJECTIVES

Using optical coherence tomography (OCT), we evaluated the effect of a cutting balloon (CB) compared with a conventional balloon after rotational atherectomy (RA) and before stenting in severely calcified coronary lesions.

BACKGROUND

A CB is designed to create discrete incisions to facilitate fracture of severely calcified plaque.

METHODS

OCT was performed preintervention (if possible), post-RA, and poststent implantation. RA modification of calcium was defined as a polished, concave, round-shaped surface. Calcium fracture was defined as a break in the calcium plate. The effects of calcium modification and stent expansion between CB (n = 18) versus conventional balloon (n = 23) following RA were compared.

RESULTS

Median patient age was 72 years with 24% on hemodialysis. The amount of calcium and the length of RA modification were comparable between the CB and conventional balloon groups. Final poststent OCT showed that the number and thickness of calcium fracture were greater after CB versus conventional balloon, resulting better stent expansion (78.9% [IQR: 72.4-88.1] vs. 66.7% [IQR: 55.0-76.7], p < 0.01). In the multivariable model, after adjusting for the amount of calcium, CB use was an independent predictor of the presence of calcium fracture (odds ratio 30.0; 95% confidence interval 2.7-994.1, p = 0.004) and an independent predictor for greater stent expansion (regression coefficient 7.4; 95% confidence interval 0.5-14.3, p = 0.04).

CONCLUSION

In severely calcified lesions calcium fracture was more often associated with RA followed by CB compared with RA followed by conventional balloon predilation before stenting. CB use was also a determinant of greater stent expansion.

Association between debulking area of rotational atherectomy and platform revolution speed-Frequency domain optical coherence tomography analysis

OBJECTIVES

In this study, we sought to investigate the association between revolution speed of rotational atherectomy (RA) and debulking area assessed by frequency domain-optical coherence tomography (FD-OCT).

BACKGROUND

The number of patients with severe calcified coronary artery disease requiring treatment with calcium ablation, such as RA, is increasing. However, there is little evidence available regarding the association between debulking area and revolution speed during RA.

METHODS

We retrospectively investigated 30 consecutive severely calcified coronary lesions in 29 patients who underwent RA under FD-OCT guidance. The association between preset revolution speed of RA and burr size-corrected debulking area of the calcified lesion was evaluated using a multivariable regression model with nonlinear restricted-cubic-spline, which can help assess nonlinear associations between variables.

RESULTS

The median age of study participants was 73 years (quartile 65-78); 82.8% were male. The median burr size was 1.5 mm (1.5-1.75); median total duration of ablation was 120 s (100-180). FD-OCT revealed that the post-procedural minimum lumen area increased significantly from 1.64 mm² (1.40-2.09) to 2.45 mm² (2.11-2.98) (p < .001). In addition, the burr size-corrected debulking area increased significantly as the preset revolution speed decreased (p = .018), especially when the revolution speed was less than 150,000 rpm. This result implies that additional lumen gain will be obtained by decreasing rpm when the burr speed is set at <150,000 rpm.

CONCLUSIONS

FD-OCT demonstrated that RA with lower revolution speed, below 150,000 rpm, has the potential to achieve greater calcium debulking effect in patients with severe calcified coronary lesions.

The clinical significance of echo-attenuated plaque in stable angina pectoris compared with acute coronary syndromes: A combined intravascular ultrasound and optical coherence tomography study

BACKGROUND

Echo-attenuated plaque (EA) on intravascular ultrasound (IVUS) is related to poor outcomes after percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) patients. However, the clinical significance of EA in stable angina pectoris (SAP) patients compared with that in ACS patients remains unclear. We assessed the relationships between EA and unstable plaque characteristics in patients with ACS and SAP.

METHODS

We investigated 609 coronary lesions in 609 patients (234 with ACS; 375 with SAP) undergoing pre-intervention IVUS and optical coherence tomography (OCT). The differences in plaque morphology and post-PCI outcomes were assessed according to the clinical status of ACS or SAP and the presence or absence of EA.

RESULTS

EA was more frequent in patients with ACS than in those with SAP (44.0% vs. 25.1%, p < 0.001). SAP-EA lesions showed thicker fibrous cap (157 ± 97 μm vs. 100 ± 58 μm, p < 0.001), smaller lipid arc (208 ± 76° vs. 266 ± 99°, p < 0.001), smaller plaque burden (83.0 ± 6.1% vs. 86.5 ± 4.1%, p < 0.001), and lower frequency of transient slow-reflow phenomenon during PCI (21.3% vs. 51.5%, p < 0.001) than ACS-EA lesions, but similar plaque vulnerability compared with ACS-non-EA lesions. SAP-EA lesions had less frequent OCT-thrombus than ACS-non-EA lesions (20.2% vs. 71.2%, p < 0.001).

CONCLUSIONS

SAP-EA lesions had less plaque vulnerability than ACS-EA lesions, but were comparable to ACS-non-EA lesions. Less frequent thrombus formation might differentiate SAP-EA lesions from ACS-non-EA lesions. A combined IVUS and OCT approach might be useful to assess plaque vulnerability in SAP-EA lesions compared with ACS lesions.

Co-localization of plaque macrophages with calcification is associated with a more vulnerable plaque phenotype and a greater calcification burden in coronary target segments as determined by OCT

BACKGROUND

The presence of plaque macrophages and microcalcifications are acknowledged features of plaque vulnerability. Experimental data suggest that microcalcifications promote inflammation and macrophages foster microcalcifications. However, co-localization of plaque macrophages and calcification (ColocCaMa) in coronary segments and its impact on plaque phenotype and lesion vulnerability is unexplored.

METHODS

Plaque morphology including ColocCaMa of calcified coronary target segments in patients with stable coronary artery disease (n = 116) was analyzed using optical coherence tomography (OCT) prior to coronary intervention. Therefore we considered macrophages co-localized with calcification if their distance in an OCT frame was <100μm and OCT-defined microcalcifications with a calcium arc <22.5°.

RESULTS

ColocCaMa was present in 29/116(25.0%) coronary segments. Calcium burden was greater (calcium volume index:1731±1421°*mm vs. 963±984°*mm, p = 0.002) and calcifications were more superficial (minimal thickness of the fibrous cap overlying the calcification 35±37μm vs. 64±72μm, p = 0.005) in the presence of ColocCaMa. Segments with ColocCaMa demonstrated a higher incidence of newly suggested features of plaque vulnerability, with a 3.5-fold higher number of OCT-defined microcalcifications (0.7±1.0 vs. 0.2±0.6, p = 0.022) and a 6.7-fold higher incidence of plaque inflammation (macrophage volume index:148.7±248.3°*mm vs. 22.2±57.4°*mm, p<0.001). Clinically, intima-media thickness (IMT) in carotid arteries was increased in patients with ColocCaMa (1.02±0.30mm vs. 0.85±0.18, p = 0.021). In a multivariate model, IMT (OR1.76 for 100μm, 95%CI 1.16-2.65, p = 0.007), HDL-cholesterol (OR0.36 for 10mg/dl, 95%CI 0.16-0.84, p = 0.017), calcium volume index (OR1.07 for 100°*mm, 95%CI 1.00-1.14, p = 0.049), macrophage volume index (OR5.77 for 100°*mm, 95%CI 2.04-16.3, p = 0.001) and minimal luminal area (OR3.41, 95%CI 1.49-7.78, p = 0.004) were independent predictors of ColocCaMa.

CONCLUSION

Plaque macrophages co-localize with calcifications in coronary target segments and this is associated with high-risk morphological features including microcalcifications and macrophage infiltration as well as with greater calcification burden. Our data may add to the understanding of the relationship between plaque macrophages, vascular calcification and their clinical impact.