Shining light on calcified lesions, plaque stabilisation and physiologic significance: new insights from intracoronary OCT

Current Management of Highly Calcified Coronary Lesions: An Overview of the Current Status

The amount of coronary calcium strongly correlates with the degree of atherosclerosis and, therefore, with the rate of future cardiac events. Calcified coronary lesions still represent a challenge for interventional cardiologists, bringing not only a higher risk of immediate complications during percutaneous coronary interventions (PCI), but also a higher risk of late stent failure due to under-expansion and/or malapposition, and therefore, have a relevant prognostic impact. Accurate identification of the calcified plaques together with the analysis of their distribution pattern within the vessel wall by intracoronary imaging is important to improve the successful treatment of these lesions. The aim of this review is to guide readers through the assessment of the calcified plaque distribution using intracoronary imaging in order to select the best devices and strategies for plaque debulking and lesion preparation.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention: Practical Application

Optical coherence tomography (OCT) provides high-resolution imaging of coronary arteries and can be used to optimize percutaneous coronary intervention (PCI). Intracoronary OCT, however, has had limited adoption in clinical practice. Novelty and relative complexity of OCT interpretation compared with the more established intravascular ultrasound, lack of a standardized algorithm for PCI guidance, paucity of data from randomized trials, and lack of rebate for intravascular imaging have contributed to the modest practical adoption of OCT. We provide a practical step-by-step guide on how to use OCT in PCI, including device set-up, simplified image interpretation, and an algorithmic approach for PCI. optimization.

Calcium Modification in Percutaneous Coronary Interventions

Moderate-severe calcification increases procedural complications and impairs long-term prognosis post-PCI. Intravascular imaging (particularly optical coherence tomography [OCT]) is useful in guiding the treatment of calcified lesions. Weighted sum of calcium length, arc, and thickness on OCT can predict adequate stent expansion, identifying when atherectomy is required. With intravascular imaging guidance, various techniques alone or in combination may be used in an algorithmic fashion to modify calcified lesions. Calcium fracture by balloon angioplasty, cutting/scoring balloons, intravascular lithotripsy (IVL), atherectomy devices, or Excimer laser improves stent expansion. Intravascular imaging is essential in the treatment of in-stent restenosis when luminal and/or abluminal peri-strut calcium is present.

Macrocalcification of intracranial vertebral artery may be related to in-stent restenosis: lessons learned from optical coherence tomography

BACKGROUND

Calcification has been proven to be a marker of atherosclerosis and is related to an increased risk of ischemic stroke. Additionally, calcification was reported to be prevalent in patients with stenotic lesions of the intracranial vertebral artery. Thus, reliable imaging facilities for evaluating plaque calcification have remarkable significance in guiding stenting and predicting patient outcomes. Optical coherence tomography (OCT) has a unique advantage in its ability to detect calcium and to achieve three-dimensional volumetric calcium characterization.

METHODS

From March 2017 to September 2018, seven cases of calcified lesions with intracranial vertebral artery stenosis were investigated using OCT, before and after the placement of an Apollo balloon-mounted stent. Transcranial color-coded duplex sonography was performed to identify restenosis with a mean follow-up time of 13.3 months in this case series.

RESULTS

All calcified lesions were evaluated quantitatively and qualitatively using OCT. Among all cases, five had macrocalcifications and two had spotty calcifications. Severe in-stent restenosis was observed in two cases, both with macrocalcifications.

CONCLUSIONS

This study suggests a potential relationship between macrocalcifications and the risk of in-stent restenosis of the intracranial vertebral artery. These preliminary findings obtained from a limited sample should be verified by prospective large-scale studies.

Intracoronary optical coherence tomography: state of the art and future directions

Optical coherence tomography (OCT) has been increasingly utilised to guide percutaneous coronary intervention (PCI). Despite the diagnostic utility of OCT, facilitated by its high resolution, the impact of intracoronary OCT on clinical practice has thus far been limited. Difficulty in transitioning from intravascular ultrasound (IVUS), complex image interpretation, lack of a standardised algorithm for PCI guidance, and paucity of data from prospective clinical trials have contributed to the modest adoption. Herein, we provide a comprehensive up-do-date overview on the utility of OCT in coronary artery disease, including technical details, device set-up, simplified OCT image interpretation, recognition of the imaging artefacts, and an algorithmic approach for using OCT in PCI guidance. We discuss the utility of OCT in acute coronary syndromes, provide a summary of the clinical trial data, list the work in progress, and discuss the future directions.

Therapeutic Approach to Calcified Coronary Lesions: Disruptive Technologies

PURPOSE OF REVIEW

Moderate or severe calcification is present in approximately one third of coronary lesions in patients with stable ischemic heart disease and acute coronary syndromes and portends unfavorable procedural results and long-term outcomes. In this review, we provide an overview on the state-of-the-art in evaluation and treatment of calcified coronary lesions.

RECENT FINDINGS

Intravascular imaging (intravascular ultrasound or optical coherence tomography) can guide percutaneous coronary intervention of severely calcified lesions. New technologies such as orbital atherectomy and intravascular lithotripsy have significantly expanded the range of available techniques to effectively modify coronary calcium and facilitate stent expansion. Calcium fracture improves lesion compliance and is essential to optimize stent implantation. Intravascular imaging allows for detailed assessment of patterns and severity of coronary calcium that are integrated into scoring systems to predict stent expansion, identifying which lesions require atherectomy for lesion modification. Guided by intravascular imaging, older technologies such as rotational atherectomy and excimer laser can be incorporated with newer technologies such as orbital atherectomy and intravascular lithotripsy into an algorithmic approach for the safe and effective treatment of patients with heavily calcified coronary lesions.

Association of Trimethylamine N-Oxide Levels and Calcification in Culprit Lesion Segments in Patients With ST-Segment-Elevation Myocardial Infarction Evaluated by Optical Coherence Tomography

The presence of calcified plaques is one of the pathological phenotypes of acute coronary syndrome (ACS) and can be frequently found in culprit lesion segments. Trimethylamine N-oxide (TMAO) is reported to be involved in vascular calcification and plaque instability. This study investigated the relationship between plasma TMAO levels and calcified lesions in culprit lesion segments in STEMI patients. A prospective series of 179 patients with STEMI were enrolled, and calcified lesions from 127 patients were analyzed by OCT. The plasma TMAO levels were measured by using stable isotope dilution liquid chromatography tandem mass spectrometry. Patients were divided into two groups according to the median plasma TMAO level. The prevalence of intimal calcified lesions in the high TMAO group was significantly higher than that in the low TMAO group (90.6 vs. 57.1%, p < 0.001; 84.4 vs. 44.4%, p < 0.001). After adjustment of traditional risk factors and medication history, patients with calcification in their culprit lesion segments had higher plasma TMAO levels than those without calcification. Moreover, plasma TMAO levels were significantly positively associated with the parameters of calcium burden, including maximal calcification arc (r = 0.392, p < 0.001), maximal calcification thickness (r = 0.443, p < 0.001), and calcified length (r = 0.466, p < 0.001). These results suggested that the level of TMAO is significantly correlated with the incidence of calcification in the culprit lesion segment, and the measurement of TMAO levels might improve clinical management in patients with heavy calcification. Clinical Trial Registration: This study is registered at ClinicalTrials.gov as NCT03593928.

Feasibility of morphological assessment of coronary artery calcification with electrocardiography-gated non-contrast computed tomography: a comparative study with optical coherence tomography

To investigate the feasibility of pre-procedural morphological assessment of coronary artery calcification in severely calcified lesions with electrocardiography (ECG)-gated non-contrast computed tomography (CT). Severely calcified coronary arteries in patients who underwent ECG-gated non-contrast CT prior to optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI) were studied retrospectively. CT and OCT data were co-registered by marking landmark structures such as side branches and reviewed side by side with cross-sectional images. The maximum calcium angle (MCA) and presence of nodular calcification (NC) were evaluated. A total of 496 cross-sections in 16 lesions were included in this analysis. The Pearson correlation coefficient between CT- and OCT-derived MCA was 0.92 (p < 0.001). Bland-Altman plots of OCT-derived MCA in relation to CT-derived MCA showed a mean bias of 4.8 degrees with 95% limits of agreement of - 69.7 to 79.4 degrees. Sensitivity, specificity, and positive and negative predictive values of CT in identifying MCA > 270 degrees were 90.3%, 79.7%, 92.1%, and 97.4%, respectively. Sensitivity, specificity, and positive and negative predictive values of CT in identifying NC were 73.3%, 97.5%, 47.8%, and 99.2%, respectively. ECG-gated non-contrast coronary CT might be helpful to obtain detailed information of severe coronary artery calcification before PCI.