Background: The use of acetylcholine for the diagnosis of vasospastic angina is recommended by international guidelines. However, its intracoronary use is still off-label due to the absence of safety studies. We aimed to perform a systematic review of the literature to identify adverse events related to the intracoronary administration of acetylcholine for vasoreactivity testing to fill this gap. Methods and results: We conducted a systematic review of observational studies and randomized controlled trials dealing with the intracoronary administration of acetylcholine. Articles were searched in MEDLINE (PubMed) using the MeSH strategy. Three independent reviewers determined whether the studies met the inclusion and exclusion criteria. A total of 434 articles were selected. Data concerning clinical characteristics, study population, acetylcholine dosage, and adverse effects were retrieved from the articles. Overall, 71,566 patients were included, of which only 382 (0.5%) developed one adverse event, and there were no fatal events reported (0%). Conclusions: Intracoronary administration of acetylcholine in the setting of coronary spasm provocation testing is safe and plays a central role in the evaluation of coronary vasomotion disorders, making it worthy of becoming a part of clinical practice in all cardiac catheterization laboratories.

Background: Recently, questions around the efficacy and effectiveness of Fractional Flow Reserve (FFR) have arisen in various clinical settings. Methods: The Clinical Outcome of FFR-guided Revascularization Strategy of Coronary Lesions (HALE-BOPP) study is an investigator-initiated, multicentre, international prospective study enrolling patients who underwent FFR measurement on at least one vessel. In accordance with the decision-making workflow and treatment, the vessels were classified in three subgroups: (i) angiorevascularized, (ii) FFR-revascularized, (iii) FFR-deferred. The primary endpoint was the occurrence of target vessel failure (TVF, cardiac death, target vessel myocardial infarction and ischemia-driven target vessel revascularization). The analysis was carried out at vessel-and patient-level. Results: 1305 patients with 2422 diseased vessels fulfilled the criteria for the present analysis. Wire-related pitfalls and transient adenosine-related side effects occurred in 0.8% (95% CI: 0.4%-1.4%) and 3.3% (95% CI: 2.5%-4.3%) of cases, respectively. In FFR-deferred vessels, the overall incidence rate of TVF was 0.024 (95% CI: 0.019-0.031) lesion/year. After a median follow-up of 3.6 years, the occurrence of TVF was 6%, 7% and 11.7% in FFR-deferred, FFR-revascularized and angio-revascularized vessels, respectively. Compared to angio-revascularized vessels, FFR-guided vessels (both FFR-revascularized and FFR-deferred vessels) showed a lower TVF incidence rate lesion/year (0.029, 95%

Background There are currently some doubts about the efficacy of fractional flow reserve (FFR)-guided revascularization in different clinical settings. Aim To evaluate the long-term outcome of an FFR-deferred strategy in daily practice. Methods The Clinical Outcome of FFR-guided Revascularization Strategy of Coronary Lesions (HALE-BOPP) is an investigator-initiated, multicenter, international prospective study consecutively enrolling patients who underwent FFR measurement on at least one vessel. According to decision-making workflow and treatment, vessels were classified in three subgroups: i) angio-revascularized, ii) FFR-revascularized, iii) FFR-deferred. The primary endpoint was the occurrence of target vessel failure (TVF, cardiac death, target vessel myocardial infarction and ischemia-driven target vessel revascularization). The analysis is carried out at vessel- and patient-level. Results Overall, 1305 patients with 2422 diseased vessels fulfilled criteria for the present analysis. Wire-related pitfalls and transient adenosine-related side effects occurred in 0.8% (95%CI 0.4%-0.1%) and 3.3% (95% 2.5%-4.3%) of cases, respectively. In FFR-deferred vessels the overall incidence rate of TVF was 0.024% (95%CI 0.019-0.031) lesion/year. After a median follow-up of 3.5 years, the occurrence of TVF was 6%, 7% and 11.7% in FFR-deferred, FFR-revascularized and angio-revascularized vessels, respectively. As compared to angio-revascularized vessels, FFR-guided vessels (both FFR-revascularized and FFR-deferred vessels) showed a lower TVF incidence rate lesion/year (0.029, 95%CI 0.024-0.034 vs. 0.049, 95%CI 0.040-0.061 respectively, p= 0.0001). This was consistent after correction for confounding factors and across subgroups of clinical interest. Patient-level analysis confirmed the lower occurrence of TVF in negative-FFR vs. positive-FFR subgroups. Conclusions In a large prospective observational study, FFR-based strategy for the deferral of coronary lesions is reliable and safe and associated with good long-term outcome.

Aims The study of coronary microcirculation has gained increasing consideration and importance in cath-lab. Despite the increase of evidence its use still remains very limited. QFR is a novel angio-based approach for the evaluation of coronary stenosis. The aim of our study was to use the QFR assessment in stable patients to recreate the IMR formula and to correlate the result of the two techniques. Methods and results From 1 June 2019 to 29 February 2019, 200 patients with CCS and indication of coronary artery angiography and referred to the cath-lab of the University Hospital of Ferrara (Italy) were enrolled. After baseline coronary angiogram, quantitative flow ratio, fractional flow reserve and index of microcirculatory resistance evaluation were performed. Pearson correlation (r) between Angio-based index of microcirculatory resistance (A-IMR) and IMR 0.32 with R2 = 0.098, P = 0.03: McNemar test showed a difference between the two test of 6.82% with 95% CI from −12.05% to 22.89%, which is not significant (P = 0.60). Bland and Altman plot showed a mean difference of 23.3 (from −26.5 to 73.1). Sensitivity, specificity, NPV and PPV were 70%, 83.3%, 75% and 70% for A-IMR value > 44.2. The area under the ROC curve for A-IMR was 0.76 (95% CI: 0.61–0.88, P = 0.0003). Conclusions We have validated for the first time the formula of the A-IMR, a tool for the calculation of microvascular resistance which does not require the use of pressure guides and the induction of hyperemia