Paclitaxel-Coated Balloon vs Uncoated Balloon for Coronary In-Stent Restenosis: The AGENT IDE Randomized Clinical Trial.

Importance: Drug-coated balloons offer a potentially beneficial treatment strategy for the management of coronary in-stent restenosis. However, none have been previously evaluated or approved for use in coronary circulation in the United States. Objective: To evaluate whether a paclitaxel-coated balloon is superior to an uncoated balloon in patients with in-stent restenosis undergoing percutaneous coronary intervention. Design, Setting, and Participants: AGENT IDE, a multicenter randomized clinical trial, enrolled 600 patients with in-stent restenosis (lesion length <26 mm and reference vessel diameter >2.0 mm to ≤4.0 mm) at 40 centers across the United States between May 2021 and August 2022. One-year clinical follow-up was completed on October 2, 2023. Interventions: Participants were randomized in a 2:1 allocation to undergo treatment with a paclitaxel-coated (n = 406) or an uncoated (n = 194) balloon. Main Outcomes and Measures: The primary end point of 1-year target lesion failure-defined as the composite of ischemia-driven target lesion revascularization, target vessel-related myocardial infarction, or cardiac death-was tested for superiority. Results: Among 600 randomized patients (mean age, 68 years; 157 females [26.2%]; 42 Black [7%], 35 Hispanic [6%] individuals), 574 (95.7%) completed 1-year follow-up. The primary end point at 1 year occurred in 17.9% in the paclitaxel-coated balloon group vs 28.6% in the uncoated balloon group, meeting the criteria for superiority (hazard ratio [HR], 0.59 [95% CI, 0.42-0.84]; 2-sided P = .003). Target lesion revascularization (13.0% vs 24.7%; HR, 0.50 [95% CI, 0.34-0.74]; P = .001) and target vessel-related myocardial infarction (5.8% vs 11.1%; HR, 0.51 [95% CI, 0.28-0.92]; P = .02) occurred less frequently among patients treated with paclitaxel-coated balloon. The rate of cardiac death was 2.9% vs 1.6% (HR, 1.75 [95% CI, 0.49-6.28]; P = .38) in the coated vs uncoated balloon groups, respectively. Conclusions and Relevance: Among patients undergoing coronary angioplasty for in-stent restenosis, a paclitaxel-coated balloon was superior to an uncoated balloon with respect to the composite end point of target lesion failure. Paclitaxel-coated balloons are an effective treatment option for patients with coronary in-stent restenosis. Trial Registration: ClinicalTrials.gov Identifier: NCT04647253.

Multivessel Coronary Function Testing Increases Diagnostic Yield in Patients With Angina and Nonobstructive Coronary Arteries.

BACKGROUND: Invasive CFT is the gold standard for diagnosing coronary vasomotor dysfunction in patients with ANOCA. Most institutions recommend only testing the left coronary circulation. Therefore, it is unknown whether testing multiple coronary territories would increase diagnostic yield. OBJECTIVES: The aim of this study was to evaluate the diagnostic yield of multivessel, compared with single-vessel, invasive coronary function testing (CFT) in patients with angina and nonobstructive coronary arteries (ANOCA). METHODS: Multivessel CFT was systematically performed in patients with suspected ANOCA. Vasoreactivity testing was performed using acetylcholine provocation in the left (20 to 200 µg) and right (20 to 80µg) coronary arteries. A pressure-temperature sensor guidewire was used for coronary physiology assessment in all three epicardial vessels. RESULTS: This multicenter study included a total of 228 vessels from 80 patients (57.8 ± 11.8 years of age, 60% women). Compared with single-vessel CFT, multivessel testing resulted in more patients diagnosed with coronary vasomotor dysfunction (86.3% vs 68.8%; P = 0.0005), coronary artery spasm (60.0% vs 47.5%; P = 0.004), and CMD (62.5% vs 36.3%; P < 0.001). Coronary artery spasm (n = 48) predominated in the left coronary system (n = 38), though isolated right coronary spasm was noted in 20.8% (n = 10). Coronary microvascular dysfunction (CMD), defined by abnormal index of microcirculatory resistance and/or coronary flow reserve, was present 62.5% of the cohort (n = 50). Among the cohort with CMD, 27 patients (33.8%) had 1-vessel CMD, 15 patients (18.8%) had 2-vessel CMD, and 8 patients (10%) had 3-vessel CMD. CMD was observed at a similar rate in the territories supplied by all 3 major coronary vessels (left anterior descending coronary artery = 36.3%, left circumflex coronary artery = 33.8%, right coronary artery = 31.3%; P = 0.486). CONCLUSIONS: Multivessel CFT resulted in an increased diagnostic yield in patients with ANOCA compared with single-vessel testing. The results of this study suggest that multivessel CFT has a role in the management of patients with ANOCA.

A Systematic Approach to the Evaluation of the Coronary Microcirculation Using Bolus Thermodilution: CATH CMD.

Coronary microvascular dysfunction (CMD) can cause myocardial ischemia in patients presenting with angina without obstructive coronary artery disease (ANOCA). Evaluating for CMD by using the thermodilution technique offers a widely accessible means of assessing microvascular resistance. Through this technique, 2 validated indices, namely coronary flow reserve and the index of microcirculatory resistance, can be computed, facilitating investigation of the coronary microcirculation. The index of microcirculatory resistance specifically estimates minimum achievable microvascular resistance within the coronary microcirculation. We aim to review the bolus thermodilution method, outlining the fundamental steps for conducting measurements and introducing an algorithmic approach (CATH CMD) to systematically evaluate the coronary microcirculation. Embracing a standardized approach, exemplified by the CATH CMD algorithm, will facilitate adoption of this technique and streamline the diagnosis of CMD.

Determining the Cause of Coronary Vasomotor Disorders in Patients With Ischemia and Nonobstructive Coronary Arteries: Design and Rationale of the DISCOVER INOCA Prospective, Multicenter Registry.

Background: Approximately 30% to 50% of patients who are referred for diagnostic coronary angiography are found to have no obstructive coronary artery disease (CAD). Ischemia and nonobstructive coronary arteries (INOCA) is increasingly recognized and encompasses coronary microvascular dysfunction, vasospastic angina, symptomatic myocardial bridging, and other vasomotor disorders. However, the prevalence of these disorders and whether underlying atherosclerotic plaque burden and morphology affect the long-term outcomes of each physiologic phenotype is unknown. Methods: The DISCOVER INOCA registry is ongoing at 8 centers in the United States and plans to enroll 500 patients with ischemic heart disease referred for angiography undergoing coronary function testing (CFT). All participants will complete patient-reported outcome measures and undergo protocol-guided angiography, acetylcholine provocation, coronary thermodilution, and intravascular imaging. Follow-up assessments occur at 30 days, 6 months, 1 year, and annually for 5 years. The primary short-term end point is the prevalence of INOCA phenotypes based on physiology and the degree of atherosclerosis based on intravascular ultrasound or optical coherence tomography (intravascular imaging). The primary long-term end point is the incidence of major adverse cardiovascular events, defined as a composite of cardiovascular death, myocardial infarction, hospitalization for cardiovascular causes, or coronary revascularization at a follow-up of 5 years. At the time of this publication, 100 participants have been enrolled. Conclusions: DISCOVER INOCA is the first prospective study of INOCA patients to integrate anatomic and physiologic measures of disease and correlate them with long-term outcomes. DISCOVER INOCA will report on the prevalence of INOCA phenotypes, the safety of comprehensive invasive CFT, and the impact of testing on diagnoses and medical therapy. Symptoms and cardiovascular adverse events at long-term follow-up will be determined in patients with no obstructive CAD undergoing angiography.