Coronary microvascular obstruction and dysfunction (CMVO) frequently arise following primary percutaneous coronary intervention (PCI), particularly in individuals with myocardial infarction. Despite the restoration of epicardial blood flow, microvascular perfusion might still be compromised, resulting in negative clinical outcomes. CMVO is a complex condition resulting from a combination of ischemia, distal thrombotic embolization, reperfusion injury, and individual susceptibilities such as inflammation and endothelial dysfunction. The pathophysiological features of this condition include microvascular spasm, endothelial swelling, capillary plugging by leukocytes and platelets, and oxidative stress. Traditional angiographic assessments, such as Thrombolysis in Myocardial Infarction (TIMI) flow grade and myocardial blush grade, have limited sensitivity. Cardiac magnetic resonance imaging (CMR) stands as the gold standard for identifying CMVO, while the index of microvascular resistance (IMR) is a promising invasive option. Treatment approaches involve powerful antiplatelet drugs, anticoagulants, and supersaturated oxygen, yet no treatment has been definitively shown to reverse established CMVO. CMVO remains a significant therapeutic challenge in coronary artery disease management. Enhancing the comprehension of its core mechanisms is vital for the development of more effective and personalized treatment strategies.

BACKGROUND: The efficacy of coronary computed tomography angiography (CCTA) versus invasive coronary angiography (ICA) among patients with stable chest pain has been studied in several trials with conflicting results. METHODS: We performed a systematic review and meta-analysis comparing CCTA first versus direct ICA among patients with stable chest pain, who were initially referred to ICA. PubMed, EMBASE, and Cochrane Central were searched for randomized controlled trials comparing the 2 strategies. Risk ratios (RRs) and mean differences with 95% CIs were computed for binary and continuous outcomes, respectively. RESULTS: Five randomized controlled trials with a total of 5727 patients were included, of whom 51.1% were referred to CCTA and 22.5% of patients had evidence of ischemia on a prior functional test. In the follow-up ranging from 1 to 3.5 years, 660 of the 2928 patients randomized to CCTA first underwent ICA (23%). Patients who underwent CCTA had lower rates of coronary revascularization (RR, 0.74 [95% CI, 0.66–0.84]; P <0.001) and stroke (RR, 0.50 [95% CI, 0.26–0.98]; P =0.043). Cardiovascular mortality (RR, 0.55 [95% CI, 0.24–1.23]; P =0.146), major adverse cardiovascular events (RR, 0.84 [95% CI, 0.64–1.10]; P =0.198), nonfatal myocardial infarction (RR, 1.09 [95% CI, 0.63–1.88]; P =0.768), and cardiovascular hospitalizations (RR, 0.91 [95% CI, 0.59–1.39]; P =0.669) did not differ significantly between groups. CONCLUSIONS: In patients with stable chest pain referred for ICA, CCTA avoided the need for ICA in 77% of patients otherwise referred for ICA. CCTA was associated with a reduction in the rates of coronary revascularization and stroke compared with direct ICA. REGISTRATION: URL: https://www.crd.york.ac.uk/prospero/ ; Unique identifier: CRD42023383143.

1. Introduction and General Concepts The pandemic resulting from the novel coronavirus (SARS-CoV-2) infection, named COVID-19, emerged in Wuhan, China, in December 2019., Since then, millions of people around the world have been affected and hundreds of thousands have died. The virus spreads mainly from person to person,, directly via the airways or indirectly through contact with contaminated surfaces and objects. Respiratory infections occur through the transmission of virus-filled droplets (> 5 μm, approximate extension of 1.5 m) or aerosols [...] 1. Introduction and General Concepts The pandemic resulting from the novel coronavirus (SARS-CoV-2) infection, named COVID-19, emerged in Wuhan, China, in December 2019., Since then, millions of people around the world have been affected and hundreds of thousands have died. The virus spreads mainly from person to person,, directly via the airways or indirectly through contact with contaminated surfaces and objects. Respiratory infections occur through the transmission of virus-filled droplets (> 5 μm, approximate extension of 1.5 m) or aerosols

Background: Bioabsorbable polymer stents with drug elution only on the abluminal surface may be safer than durable polymer drug-eluting stents. Objective: To report the experimental findings with the Inspiron (TM) stent - a bioabsorbable polymer-coated stent with sirolimus release from the abluminal surface only, recently approved for clinical use. Methods: 45 stents were implanted in the coronary arteries of 15 pigs. On day 28 after implantation, angiographic, intracoronary ultrasonographic and histomorphological data were collected. Five groups were analyzed: Group I (nine bare-metal stents); Group II (nine coated with bioabsorbable polymer on the luminal and abluminal surfaces); Group III (eight stents coated with bioabsorbable polymer on the abluminal surface); Group IV (nine stents with bioabsorbable polymer and sirolimus on the luminal and abluminal surfaces); and Group V (ten stents with bioabsorbable polymer and sirolimus only on the abluminal surface). Results: The following results were observed for Groups I, II, III, IV and V, respectively: percentage stenosis of 29 +/- 20; 36 +/- 14; 33 +/- 19; 22 +/- 13 and 26 +/- 15 (p = 0.443); late lumen loss (in mm) of 1.02 +/- 0.60; 1.24 +/- 0.48; 1.11 +/- 0.54; 0.72 +/- 0.44 and 0.78 +/- 0.39 (p = 0.253); neointimal area (in mm(2)) of 2.60 +/- 1.99; 2.74 +/- 1.51; 2.74 +/- 1.30; 1.30 +/- 1.14 and 0.97 +/- 0.84 (p = 0.001; Groups IV and V versus Groups I, II and III); and percentage neointimal area of 35 +/- 25; 38 +/- 18; 39 +/- 19; 19 +/- 18 and 15 +/- 12 (p = 0.001; Groups IV and V versus Groups I, II and III). Injury and inflammation scores were low and with no differences between the groups. Conclusion: The Inspiron (TM) stent proved to be safe and was able to significantly inhibit the neointimal hyperplasia observed on day 28 after implantation in porcine coronary arteries.