Coronary Optical Coherence Tomography and Cardiac Magnetic Resonance Imaging to Determine Underlying Causes of Myocardial Infarction With Nonobstructive Coronary Arteries in Women.

BACKGROUND: Myocardial infarction with nonobstructive coronary arteries (MINOCA) occurs in 6% to 15% of myocardial infarctions (MIs) and disproportionately affects women. Scientific statements recommend multimodality imaging in MINOCA to define the underlying cause. We performed coronary optical coherence tomography (OCT) and cardiac magnetic resonance (CMR) imaging to assess mechanisms of MINOCA. METHODS: In this prospective, multicenter, international, observational study, we enrolled women with a clinical diagnosis of myocardial infarction. If invasive coronary angiography revealed <50% stenosis in all major arteries, multivessel OCT was performed, followed by CMR (cine imaging, late gadolinium enhancement, and T2-weighted imaging and T1 mapping). Angiography, OCT, and CMR were evaluated at blinded, independent core laboratories. Culprit lesions identified by OCT were classified as definite or possible. The CMR core laboratory identified ischemia-related and nonischemic myocardial injury. Imaging results were combined to determine the mechanism of MINOCA, when possible. RESULTS: Among 301 women enrolled at 16 sites, 170 were diagnosed with MINOCA, of whom 145 had adequate OCT image quality for analysis; 116 of these underwent CMR. A definite or possible culprit lesion was identified by OCT in 46.2% (67/145) of participants, most commonly plaque rupture, intraplaque cavity, or layered plaque. CMR was abnormal in 74.1% (86/116) of participants. An ischemic pattern of CMR abnormalities (infarction or myocardial edema in a coronary territory) was present in 53.4% (62/116) of participants undergoing CMR. A nonischemic pattern of CMR abnormalities (myocarditis, takotsubo syndrome, or nonischemic cardiomyopathy) was present in 20.7% (24/116). A cause of MINOCA was identified in 84.5% (98/116) of the women with multimodality imaging, higher than with OCT alone (P<0.001) or CMR alone (P=0.001). An ischemic cause was identified in 63.8% of women with MINOCA (74/116), a nonischemic cause was identified in 20.7% (24/116) of the women, and no mechanism was identified in 15.5% (18/116). CONCLUSIONS: Multimodality imaging with coronary OCT and CMR identified potential mechanisms in 84.5% of women with a diagnosis of MINOCA, 75.5% of which were ischemic and 24.5% of which were nonischemic, alternate diagnoses to myocardial infarction. Identification of the cause of MINOCA is feasible and has the potential to guide medical therapy for secondary prevention. Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02905357.

Clinical Considerations for Use of SGLT2 Inhibitor Therapy in Patients with Heart Failure and Reduced Ejection Fraction: A Review.

Heart failure (HF) continues to increase in prevalence, representing a significant burden to healthcare systems in the USA. Despite several established HF therapies, particularly for HF with reduced ejection fraction (HFrEF), rates of HF hospitalizations and cardiovascular (CV) mortality remain very high. Type 2 diabetes (T2D) is an important risk factor for HF, with the two conditions often occurring concurrently. Several CV outcomes trials have shown that the sodium-glucose cotransporter 2 inhibitor (SGLT2i) class of antihyperglycemic drugs reduces the risk of HF-related outcomes in patients with T2D and either established CV disease or multiple CV risk factors. Subsequently, there have been large clinical studies that have investigated the effects of SGLT2is in patients with HFrEF, with or without T2D, which have shown that both dapagliflozin and empagliflozin have significant reductions in hospitalization for HF and CV mortality. These data led to US Food and Drug Administration approval of dapagliflozin and empagliflozin as a novel treatment pathway for patients with HFrEF; empagliflozin has subsequently been approved for the treatment of HF regardless of ejection fraction. A clinical practice algorithm can assist cardiologists in identifying patients who may be eligible for SGLT2i treatment as well as the appropriate timeframe for initiating therapy and the parameters for patient monitoring. Given the evidence that SGLT2is are beneficial in the management of HF, specifically HFrEF, irrespective of underlying T2D, evidence-based recommendations and greater clinician familiarity can facilitate the integration of SGLT2is into general HF therapeutic management.

Coronary Plaque Characteristics in Hemodialysis-Dependent Patients as Assessed by Optical Coherence Tomography.

Coronary arteries in patients with chronic kidney disease (CKD) have been shown to exhibit more extensive atherosclerosis and calcium. We aimed to assess characteristics of coronary plaque in hemodialysis (HD)-dependent patients using optical coherence tomography (OCT). This was a multicenter, retrospective study of 124 patients with stable angina who underwent OCT imaging. Sixty-two HD-dependent patients who underwent pre-intervention OCT for coronary artery disease were compared 1:1 with a cohort of patients without CKD, matched for age, diabetes mellitus, gender, and culprit vessel. Baseline characteristics were comparable. Pre-intervention OCT imaging identified 62 paired culprit, 53 paired non-culprit, and 19 paired distal vessel lesions. Lesion length, minimum lumen area, and area stenosis were similar between groups. The HD-dependent group had greater mean calcium arcs in culprit (54.3° vs 26.4°, p = 0.004) and non-culprit lesions (34.3° vs 24.5°, p = 0.02) and greater maximum calcium arc in distal vessel segments (101.6° vs 0°, p = 0.03). There were no differences in lipid arcs between groups. There was a higher prevalence of thin intimal calcium, defined as an arc of calcium >30° within intima <0.5 mm thick, in patients in the HD-dependent group (41.9% vs 4.8%, p <0.001). There was a higher prevalence of calcified nodules in the HD-dependent group (24.2% vs 9.7%, p = 0.049) but no differences in medial calcification or thin-cap fibroatheroma. In conclusion, in this OCT study, HD-dependent patients, compared with matched patients without CKD, had more extensively distributed coronary calcium and uniquely, a higher prevalence of non-atherosclerotic thin intimal calcium. This thin intimal calcium may cause an overestimation of calcium burden by intravascular ultrasound and may contribute to the lack of correlation between increased coronary artery calcification scores with long-term outcomes in patients with CKD.