Impact of plaque characteristics on percutaneous coronary intervention-related microvascular dysfunction: insights from angiographic microvascular resistance and intravascular ultrasound

BACKGROUND: The correlation between percutaneous coronary intervention (PCI)-related microvascular dysfunction (MVD) and plaque characteristics remains unclear. To investigate this correlation and its prognosis, we assessed changes in MVD by angiographic microvascular resistance (AMR) and intracoronary ultrasound scans after PCI. METHODS: We conducted a retrospective study that enrolled 250 patients with coronary artery disease between July 2016 and December 2018. We collected demographic characteristics, laboratory tests, coronary angiography (CAG) and intracoronary ultrasound findings. We calculated quantitative flow ratio (QFR) and AMR by CAG. The endpoint was vessel-oriented composite outcomes (VOCOs). RESULTS: After 47 exclusions, we divided 203 cases into a deteriorated group (n=139) and an improved group (n=64) based on AMR change after PCI. Compared with the improved group, the deteriorated group had smaller lumen area [3.03 (interquartile range, 2.20–3.91) vs. 3.55 mm(2) (interquartile range, 2.45–4.57), P=0.033], higher plaque burden [78.92% (interquartile range, 73.95–82.61%) vs. 71.93% (interquartile range, 62.70–77.51%), P<0.001], and higher proportion of lipidic components (13.86%±4.67% vs. 11.78%±4.41%, P=0.024). Of 186 patients who completed 4.81±1.55 years follow-up, 56 developed VOCOs. Receiver-operating characteristic (ROC) curve analysis showed post-PCI AMR and VOCOs correlation (area under the curve: 0.729, P<0.001). Multivariate regression analysis showed post-PCI AMR >285 mmHg·s/m correlated with adverse outcome (hazard ratio =4.350; 95% confidence interval: 1.95–9.703; P<0.001). CONCLUSIONS: Intravascular ultrasound (IVUS) imaging and AMR revealed an association of post-PCI MVD with a smaller lumen area, more severe plaque burden, and a higher percentage of lipidic components. Post-PCI MVD was an independent risk factor for poor prognosis.