The Year in Cardiology

Coronary Interventions: The Year in Cardiology 2019

Andreas Baumbach; Christos V. Bourantas; PatrickW. Serruys; William Wijns

Disclosures

Eur Heart J. 2020;41(3):394-405. 

In This Article

Vulnerable Plaque and Patient Detection

The event rate of patients undergoing revascularization and especially of those admitted with an ACS is high- at short-term follow-up.[50] The identification of high-risk patients has recently attracted attention as novel pharmacotherapies have been introduced that appear able to modify atherosclerotic plaque and inhibit disease progression. However, these new therapies have significant limitations as they are associated with increased cost or side effects. Accurate risk stratification and identification of high-risk individuals is expected to allow a personalized therapy and aggressive treatment of these patients with novel medications that appear to improve outcomes in vulnerable populations.[51]

Large scale prospective intravascular imaging studies of coronary atherosclerosis have highlighted the value of IVUS in detecting vulnerable plaques that are likely to progress and cause events and in stratifying more accurately cardiovascular risk. In 2019, the Lipid-Rich Plaque (LRP) and the CLIMA studies were reported which for the first time assessed the efficacy of near-infrared spectroscopy (NIRS)-IVUS and of OCT in detecting vulnerable plaques.[52,53] The LRP registry included 1563 patients with suspected CAD that had coronary angiography and possible ad hoc PCI. NIRS-IVUS imaging was performed in the non-culprit vessels in at least two major coronary arteries with length >50 mm. At 2-year follow-up, patients with increased lipid burden (4 mm lipid core burden index, maxLCBI4mm > 400) had a higher incidence of non-culprit MACE than those with lipid-free plaques (13% vs. 6%, P < 0.0001). Patient-level (adjusted HR 1.89, 95% CI 1.26–2.83; P = 0.0021) and lesion-level (adjusted HR 3.39, 95% CI 1.85–6.20; P < 0.0001) analysis demonstrated that maxLCBI4mm >400 was independent predictor of MACE at 2-year follow-up. The LRP study provided evidence for the prognostic implications of plaque composition but it failed to investigate the synergetic value of NIRS and IVUS in predicting events as IVUS analysis was not complete but restricted to the 4 mm segment with the maxLCBI.

The CLIMA study was a prospective multicentre registry that investigated the prognostic implications of OCT-derived plaque characteristic in 1003 patients who had coronary angiography for clinical purposes and OCT imaging of the untreated proximal left anterior descending coronary artery.[53] In this study, a minimum lumen area <3.5 mm2, a lipid arc >180°, a fibrous cap thickness <75 μm, and the presence of macrophages accumulations were independent predictors of the combined endpoint cardiac death and target segment MI. Patients having lesions with all the above plaque features had a higher event rate than the other patients (18.9% vs. 3.0%, P < 0.001).

Advances in Coronary Imaging

Summarizing the results of these studies and taking into consideration the findings of previous reports it appears that plaque characteristics provides useful prognostic information at a lesion and patient level; but they have a limited accuracy in predicting events. Over the last years, several methodologies have been introduced to enhance the efficacy of the existing modalities in assessing plaque characteristics and an effort has been made to develop hybrid-multimodality intravascular imaging catheters that will allow a complete assessment of plaque morphology and biology. In 2019, the first in man application of the combined IVUS-OCT catheter has been presented.[54] In addition, this year the first in man application of a polarization sensitive OCT imaging system was presented; this modality is expected to enable better plaque characterization and more detailed evaluation of its components.[55] Finally, two reports have recently examined the efficacy of attenuation compensation technique, a post-processing methodology that appears able to enhance OCT imaging depth and enable more accurate evaluation of plaque burden in heavily diseased segments.[56,57] These reports highlighted the potential of this approach in assessing plaque area in heavily diseased native vessels but also demonstrated significant limitations of this technique, because of imaging artefacts, in stented segments.

Cumulative evidence has highlighted the implications of the local haemodynamic forces on atherosclerotic disease progression and destabilization. In 2019, an analysis of the Integrated Biomarkers Imaging Study 4 (IBIS-4) has shown that the shear stress distribution estimated using computational fluid dynamic analysis adds value in predicting atherosclerotic disease progression and changes in plaque morphology, while a meta-analysis of the Providing Regional Observations to Study Predictors of Events in the Coronary Tree (PROSPECT) study has shown that estimation of plaque stress by processing virtual histology-IVUS images enables more accurate identification of lesions that will cause events in future.[58,59] Acknowledging the importance of the local haemodynamic forces on atherosclerotic disease progression in native and stented segments expert recommendations have been recently published in a consensus document which describes the existing methodologies and their value for research and possibly clinical practice in the future.[60]

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