Coronary plaque dimensions and composition by intravascular ultrasound radio frequency lesion segment analysis in stable and unstable angina patients

Intravascular ultrasound insights into the unstable features of the coronary atherosclerotic plaques: A systematic review and meta-analysis

BACKGROUND

There is a lack of a comprehensive picture of plaque geometry and composition of unstable atherosclerotic lesions as observed with intravascular ultrasound techniques. We analysed through a systematic review with meta-analysis 39 characteristics of atherosclerotic plaques in three scenarios involving culprit and non-culprit lesions from acute coronary syndromes vs stable angina pectoris patients, and culprit vs non-culprit lesions in acute coronary syndromes patients.

METHODS

A systematic search of PubMed and EMBASE, from inception to April 2020 was performed. The combined odds ratios or mean differences of all IVUS characteristics were calculated with random-effects models.

RESULTS

Twenty-eight studies involving 5434 subjects, and 5618 lesions were included. Culprit lesions in acute coronary syndromes have larger plaque areas and remodeling indexes (MD = 0.13 [0.08; 0.17], p < 0.001) and contained larger necrotic cores (MD = 0.67 (95% CI 0.19;1.15), p = 0.006) that stable angina culprit lesions. In acute patients, culprit plaques were also more remodeled, had larger necrotic cores and had more frequently a Thin-Cap Fibroatheroma morphology (OR = 1.79 (95% CI 1.21; 2.65), p = 0.004) than non-culprit lesions. Non-culprit lesions in acute syndromes were more often ruptured (OR = 2.25 (95% CI:1.05; 4.82), p = 0.037) or Thin-Cap Fibroatheromas than in stable angina.

CONCLUSION

Culprit lesions from acute coronary patients are larger, more positively remodeled and contained more lipids as compared to stable angina lesions or non-culprit in acute patients. Non culprit lesions are also more often complicated or vulnerable in acute than stable patients.

[Intravascular ultrasound for recognition of atherosclerotic plaques and plaque composition. Current state of the diagnostic value]

Coronary atherosclerosis including acute coronary syndrome (ACS) is the leading cause of death in the western world and in the majority of patients is caused by plaque rupture in flow-limiting and non-flow-limiting angiographically intermediate stenoses. Histopathologic analyses have shown the relationship of plaque composition to acute clinical events and therefore to the vulnerability of coronary lesions. Knowledge of remodeling processes of the coronary artery has focused interest on non-flow-limiting lesions of the coronary tree. Intravascular ultrasound (IVUS) can demonstrate discrepancies between the extent of coronary atherosclerosis and angiographic imaging by in vivo plaque imaging. In addition the spectral analysis of IVUS-derived radiofrequency (RF) data enables more precise analysis of the plaque composition and plaque type.As IVUS is best able to assess stent underexpansion and malapposition the guidance of catheter-based coronary interventions plays a major role in angiographically unclear lesions even in the drug-eluting stent era. In the field of percutaneous coronary interventions (PCI) IVUS can influence the therapy and therefore optimize the stratification of patients.In terms of secondary prevention it is of great clinical importance to detect progression of coronary artery disease and moreover to predict coronary lesions with significant progression up to ACS. Coronary angiography and clinical parameters are poor surrogates to predict future events in a broad cohort of patients after PCI. In addition non-invasive imaging fails to identify coronary plaques with potential rupture and subsequent ACS. This highlights the need to identify potentially high risk lesions. However, prospective studies with IVUS-RF imaging to detect lesions that are considered to be prone to rupture showed no evidence for catheter-based invasive treatment of a non-flow-limiting high risk plaque.In the future the integrated combination of multiple technologies (e.g. IVUS-RF and optical coherence tomography) can further improve the accuracy of the analysis of high risk lesions.