Aims: The role of antiplatelet therapy in patients with spontaneous coronary artery dissection (SCAD) undergoing initial conservative management is still a matter of debate, with theoretical arguments in favour and against its use. The aims of this article are to assess the use of antiplatelet drugs in medically treated SCAD patients and to investigate the relationship between single (SAPT) and dual (DAPT) antiplatelet regimens and 1-year patient outcomes. Methods and results: We investigated the 1-year outcome of patients with SCAD managed with initial conservative treatment included in the DIssezioni Spontanee COronariche (DISCO) multicentre international registry. Patients were divided into two groups according to SAPT or DAPT prescription. Primary endpoint was 12-month incidence of major adverse cardiovascular events (MACE) defined as the composite of all-cause death, non-fatal myocardial infarction (MI), and any unplanned percutaneous coronary intervention (PCI). Out of 314 patients included in the DISCO registry, we investigated 199 patients in whom SCAD was managed conservatively. Most patients were female (89%), presented with acute coronary syndrome (92%) and mean age was 52.3 ± 9.3 years. Sixty-seven (33.7%) were given SAPT whereas 132 (66.3%) with DAPT. Aspirin plus either clopidogrel or ticagrelor were prescribed in 62.9% and 36.4% of DAPT patients, respectively. Overall, a 14.6% MACE rate was observed at 12 months of follow-up. Patients treated with DAPT had a significantly higher MACE rate than those with SAPT [18.9% vs. 6.0% hazard ratios (HR) 2.62; 95% confidence intervals (CI) 1.22–5.61; P = 0.013], driven by an early excess of non-fatal MI or unplanned PCI. At multiple regression analysis, type 2a SCAD (OR: 3.69; 95% CI 1.41–9.61; P = 0.007) and DAPT regimen (OR: 4.54; 95% CI 1.31–14.28; P = 0.016) resulted independently associated with a higher risk of 12-month MACE. Conclusions: In this European registry, most patients with SCAD undergoing initial conservative management received DAPT. Yet, at 1-year follow-up, DAPT, as compared with SAPT, was independently associated with a higher rate of adverse cardiovascular events (ClinicalTrial.gov id: NCT04415762).

Microparticles (MP) are cell-derived fragments known to be increased in the blood of patients with acute coronary syndromes. We aimed to assess, in ST elevation myocardial infarction (STEMI), the systemic and local (in the culprit coronary artery) levels of platelet-derived MP (PMP, CD42+CD31+) and endothelial-derived MP (EMP, CD42−CD31+) and their relation to indexes of microvascular obstruction (MVO). In 78 STEMI patients undergoing successful primary percutaneous coronary intervention, blood samples were sequentially drawn from the aorta and the culprit coronary artery for cytofluorimetric MP detection. Thrombolysis in myocardial infarction (TIMI) flow, thrombus score (TS), corrected TIMI frame count (cTFC), myocardial blush grade (MBG), quantitative blush evaluator (QuBE) score, and 90 min ST resolution (ΣSTR) were calculated. Both PMP and EMP levels were significantly higher in the intracoronary than in the aortic blood samples. Intracoronary PMP and EMP levels were positively related to TS and cTFC and inversely related to MBG and QuBE. Aortic PMP (but not EMP) levels were related to TS and cTFC and, inversely, to QuBE. Intracoronary PMP were independently related to angiographic and electrocardiographic MVO in a multivariate model. The correlations of intracoronary EMP and of both systemic and intracoronary PMP levels with TS support the role of MP as markers of ongoing thrombosis. Moreover, the correlation of intracoronary MP with indexes of microvascular dysfunction suggests, for the first time, a possible direct role of MP in the pathogenesis of MVO.

Background—: Frequency-domain optical coherence tomography (FD-OCT) is easily able to define both pre- and post-stenting features of the atherosclerotic plaque that can potentially be related to periprocedural complications. We sought to examine which FD-OCT-defined characteristics, assessed both before and after stent deployment, predicted periprocedural (type IVa) myocardial infarction (MI). Methods and Results—: FD-OCT was performed before and after coronary stenting in 50 patients undergoing percutaneous coronary intervention (PCI) for either non-ST segment elevation MI (NSTEMI) or stable angina. All patients underwent single-vessel stenting, and only drug-eluting stents were implanted. Troponin T was analyzed on admission, before PCI, and at 12 and 24 hours after PCI, and type IVa MI was defined in stable angina as a rise of at least 3× upper reference limit and in NSTEMI as a pre-PCI troponin T fall, followed by post-PCI troponin T rise >20%. Type IVa MI was diagnosed in 21 patients, while the remaining 29 represented the control group. FD-OCT analysis showed that thin-cap fibroatheroma (76.2% versus 41.4%; P =0.017) prior to PCI, intrastent thrombus (61.9% versus 20.7%; P =0.04), and intrastent dissection (61.9% versus 31%; P =0.03) after PCI were significantly more frequent in type IVa MI than in the control group. Multivariate logistic regression analysis confirmed thin-cap fibroatheroma (OR 29.7, 95% CI 1.4 to 32.1), intrastent thrombus (OR 5.5, CI 1.2 to 24.9) and intrastent dissection (OR 5.3, CI 1.2 to 24.3) as independent predictors of type IVa MI. Conclusions—: In conclusion, presence of thin-cap fibroatheroma at pre-PCI FD-OCT and of intrastent thrombus and intrastent dissection at post-PCI FD-OCT predict type IVa MI in a contemporary sample of patients treated with second-generation drug-eluting stents. Interestingly, 2 of the 3 predictors of type IVa MI were not apparent at pre-PCI FD-OCT.