Understanding Patient Characteristics and Coronary Microvasculature: Early Insights from the Coronary Microvascular Disease Registry.

Coronary angiography has limitations in accurately assessing the coronary microcirculation. A new comprehensive invasive hemodynamic assessment method utilizing coronary flow reserve (CFR) and the index of microvascular resistance (IMR) offers improved diagnostic capabilities. This study aimed to present early real-world experience with invasive hemodynamic assessment of the coronary microvasculature in symptomatic patients with nonobstructive coronary artery disease (CAD) from the Coronary Microvascular Disease Registry, which is a prospective, multi-center registry that standardized the evaluation of patients with angina and nonobstructive CAD who underwent invasive hemodynamic assessment of the coronary microvasculature using the Coroventis CoroFlow Cardiovascular System. All patients underwent comprehensive invasive hemodynamic assessment. Analysis was performed on the first 154 patients enrolled in the Coronary Microvascular Disease Registry; their mean age was 62.4 years and 65.6% were female. A notable proportion of patients (31.8%) presented with a Canadian Cardiovascular Society Angina Score of 3 or 4. Coronary microvascular dysfunction was diagnosed in 39 of 154 patients (25.3%), with mean fractional flow reserve of 0.89 ± 0.43, mean resting full cycle ratio of 0.93 ± 0.08, mean CFR of 1.8 ± 0.9, and mean IMR of 36.26 ± 19.23. No in-hospital adverse events were reported in the patients. This study demonstrates the potential of invasive hemodynamic assessment using CFR and IMR to accurately evaluate the coronary microvasculature in patients with nonobstructive CAD. These findings have important implications for improving the diagnosis and management of coronary microvascular dysfunction, leading to more targeted and effective therapies for patients with microvascular angina.

Clinical outcomes and treatment after drug-eluting stent failure: the absence of traditional risk factors for in-stent restenosis.

BACKGROUND: The optimal percutaneous treatment of drug-eluting stent (DES) in-stent restenosis (ISR) and the correlates for recurrent DES ISR remain unclear. METHODS AND RESULTS: From 2003 to 2008, 563 patients presenting with recurrent symptoms of ischemia and angiographic ISR after DES implantation were included. Of these, 327 were treated with re-DES (58.1%), 132 underwent vascular brachytherapy (23.4%), and 104 were treated with conventional balloon angioplasty (18.5%). Variables associated with target lesion revascularization at 1 year were explored by individual proportional hazard models. This population presents a high prevalence of comorbidities, including diabetes (43.7%), previous myocardial infarction (MI) (45.8%), coronary bypass graft surgery (39.2%), chronic renal failure (18.8%), and heart failure (17.3%). Baseline clinical characteristics were balanced among the 3 groups; however, patients undergoing vascular brachytherapy presented with more complex lesions and a higher prevalence of prior stent/vascular brachytherapy failure than did the rest of the population. The overall incidence of recurrent DES failure at 1-year follow-up was 12.2%, which was similar among the 3 groups (P=0.41). The rate of the composite end point (death, Q-wave-MI and target lesion revascularization) at 1-year follow-up was 14.1% for re-DES, 17.5% for vascular brachytherapy, and 18.0% for conventional balloon angioplasty (P=0.57). After univariable analysis tested the traditional known covariates related to ISR, none of them were associated with repeat target lesion revascularization. CONCLUSIONS: Recurrence of ISR after DES treatment failure is neither infrequent nor benign, and optimal therapy remains unclear and challenging. Given the absence of traditional risk factors for ISR in this population, further research is required to elucidate both the correlates involved in DES ISR and the optimal treatment for this condition.