(1) Background: In spite of the undeniable clinical value of the index of microvascular resistance (IMR) in assessing the status of coronary microcirculation, its use globally remains very low. The aim of this study was to validate the novel single-view, pressure-wire- and adenosine-free angiographic microvascular resistance (AMR) index, having the invasive wire-based IMR as a reference standard. (2) Methods: one hundred and sixty-three patients (257 vessels) were investigated with pressure wire-based IMR. Microvascular dysfunction (CMD) was defined by IMR ≥ 25. AMR was independently computed from the diagnostic coronary angiography in a blinded fashion. (3) Results: AMR demonstrated a good correlation (r = 0.83, p < 0.001) and diagnostic performance (AUC 0.94; 95% CI: 0.91 to 0.97) compared with wire-based IMR. The best cutoff value for AMR in determining IMR ≥ 25 was 2.5 mmHg*s/cm. The overall diagnostic accuracy of AMR was 87.2% (95% CI: 83.0% to 91.3%), with a sensitivity of 93.5% (95% CI: 87.0% to 97.3%), a specificity of 82.7% (95% CI: 75.6% to 88.4%), a positive predictive value of 79.4% (95% CI: 71.2% to 86.1%) and a negative predictive value of 94.7% (95% CI: 89.3% to 97.8%). No difference in terms of CMD rate was described among different clinical presentations. (4) Conclusions: AMR derived solely from a single angiographic view is a feasible computational alternative to pressure wire-based IMR, with good diagnostic accuracy in assessing CMD.

The Drug Coated Balloon Academic Research Consortium project originated from the lack of standardization and comparability between studies using drug-coated balloons in the treatment of obstructive coronary artery disease. This document is a collaborative effort between academic research organizations and percutaneous coronary intervention societies in Europe, the USA, and Asia. This consensus sought to standardize study designs and endpoints for clinical trials involving drug-coated balloons, including defining angiographic, intravascular, and non-invasive imaging methods for lesion assessment, alongside considerations for post-revascularization pharmaco-therapy. The concept of ‘blended therapy’, which advocates for combining device strategies, is also discussed. This paper delineates study types, endpoint definitions, follow-up protocols, and analytical approaches, aiming to provide consistency and guidance for interventional cardiologists and trialists.

Background and Aims: In randomized clinical trials of patients undergoing percutaneous coronary intervention (PCI) for de novo small-vessel coronary artery disease (SV-CAD), paclitaxel-coated balloon (PCB) angioplasty showed mid-term angiographic or clinical non-inferiority to drug-eluting stent (DES) implantation. Nevertheless, these trials have sample size limitations, and the relative safety and efficacy beyond the first year remain uncertain. Methods: The ANDROMEDA study was a collaborative, investigator-initiated, individual patient data meta-analysis comparing 3 year clinical outcomes between PCB angioplasty and DES implantation for the treatment of de novo SV-CAD. Multiple electronic databases (PubMed, Scopus, ScienceDirect, and Web of Science) were searched from May 2010 to June 2024 to identify eligible trials. All the following eligibility criteria were required: (i) random allocations of treatments; (ii) patients with SV-CAD; (iii) treatment with PCB or DES; and (iv) clinical follow-up of at least 36 months. The primary and co-primary endpoints were major adverse cardiac events (MACE) and target lesion failure (TLF), respectively. The protocol was registered with PROSPERO (CRD42023479035). Results: Individual patient data from three randomized trials, including a total of 1154 patients and 1360 lesions, were combined. At 3 years, PCB was associated with a lower risk of MACE compared with DES [hazard ratio (HR) 0.67, 95% confidence interval (CI) 0.47–0.96], due to a lower risk of myocardial infarction and target vessel revascularization. This benefit persisted after multivariable adjustment (HR 0.75, 95% CI 0.58–0.96), but did not reach statistical significance in the two-stage analysis (HR 0.67, 95% CI 0.43–1.04). At the landmark analysis, the risk of MACE between groups was consistent over time. At 3 years, TLF was not significantly different between PCB and DES groups. Reconstructed time-to-event information from a fourth trial was included in a sensitivity analysis (1384 patients and 1590 lesions), showing consistent results in terms of TLF (HR 0.87, 95% CI 0.63–1.20). The comparison between PCB and second-generation DES did not reveal significant differences in 3 year TLF (HR 1.03, 95% CI 0.70–1.50). Conclusions: In patients undergoing PCI for de novo SV-CAD, PCB angioplasty is associated with a reduction in MACE and a non-significant difference in TLF at 3 year follow-up compared with DES implantation. The restriction of the comparator group to second-generation DES does not alter the main conclusions. Larger trials comparing contemporary devices at a more prolonged follow-up are warranted to confirm these findings.