Tissue characterization and phenotype classification in patients presenting with acute myocardial infarction: Insights from the iWonder study

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.

Morphology and phenotype characteristics of atherosclerotic plaque in patients with acute coronary syndrome: contemporary optical coherence tomography findings

BACKGROUND

Contemporary optical coherence tomography (OCT) findings in patients with acute coronary syndromes (ACS) are still subject of controversy. We sought to use OCT to evaluate plaque morphology and phenotype classification in patients with ACS.

METHODS

Using optical coherence tomography, culprit lesions were morphologically classified as plaque rupture, plaque erosion, calcified nodule, thin-cap fibroatheroma, thick-cap fibroatheroma (TCFA) or fibrotic, fibrocalcific or fibrolipidic plaque. Quantitative and qualitative analyses also included cholesterol crystals, neovascularization, spotty calcification and thrombus.

RESULTS

Of the 110 lesions imaged from June 2012 to April 2016, 54 (49%) were in patients with unstable angina (UA), 31 (28%) were in non-ST-elevation myocardial infarction (STEMI) patients and 25 (23%) were in STEMI patients. Compared with STEMI patients, patients with UA/non-STEMI were older and had more hypertension, hypercholesterolemia, known coronary artery disease, prior myocardial infarction and higher use of antiplatelet therapy. More patients with STEMI had lipidic arc >90% (36.6 versus 70.8%, P = 0.003), red and mixed thrombus (12.9 versus 28.0% and 7.1 versus 44.0%, respectively, all P < 0.001), plaque rupture (29.4 versus 76.0%, P < 0.001) and TCFA (57.1 versus 84.0%; P = 0.01). Predictors of plaque rupture were STEMI at presentation (odds ratio: 9.35, 95% confidence interval: 1.66-52.61, P = 0.01) and diabetes mellitus (odds ratio: 6.16, 95% confidence interval: 1.33-28.58, P = 0.02).

CONCLUSIONS

In this single-center study, the culprit lesion of patients with STEMI had more lipid, red and mixed thrombus, plaque rupture and TCFA versus patients with UA/non-STEMI. Clinical presentation may be driven by distinct pathophysiologic mechanisms in patients with ACS.

Vulnerable plaques, more than meets the i

Intravascular imaging plays a key role in the identification of mechanisms of acute coronary syndromes Post processing IVUS algorithms (IMAP-IVUS and VH-IVUS) for tissue characterization have not been widely adopted due to current limitations Future development will allow easier, faster, and more accurate identification of vulnerable plaques, ultimately allowing prognostication of various interventions.