Relentless mechanical work of the heart is powered by continuous oxygen consumption. How the heart uses oxygen is a defining feature of its health. Invasive studies have established that impaired oxygen consumption by the myocardium predicts contractile dysfunction and adverse outcomes. Despite its importance, noninvasive quantification of myocardial oxygen use remains limited. Magnetic resonance imaging (MRI) signal is known to be sensitive to blood oxygenation and has the potential to quantify myocardial oxygen consumption noninvasively, without exogenous contrast agents and free of ionizing radiation. However, its clinical translation has been impeded by the need for complex biophysical calibration, vulnerability to imaging artifacts and consistent vital motions, and the requirement of lengthy acquisition times. Here, we introduce a rapid, self-calibrated cardiac MRI framework that overcomes these barriers through high-resolution, motion-resolved coronary sinus oximetry, which can quantify myocardial oxygen extraction of the whole heart within 3 minutes. We optimized the imaging parameters via numerical simulations and validated them against invasive coronary sinus catheterization in a porcine model. We combined the method with clinical MRI sequences and demonstrated the feasibility of quantifying myocardial oxygen consumption and myocardial oxygen efficiency in patients with and without heart failure secondary to myocardial infarction in a single institution. This needle-free approach establishes a practical framework for noninvasive characterization of myocardial oxygen metabolism. It holds the potential to facilitate early disease detection, inform personalized therapeutic strategies, and guide the development of cardiometabolic therapies aimed at addressing the ongoing heart failure epidemic.

BACKGROUND AND AIMS:Intramyocardial hemorrhage (IMH) after reperfused ST-elevation myocardial infarction (STEMI) is associated with adverse outcomes, yet no therapy specifically targets it. Dexrazoxane (DXZ) may mitigate iron-mediated injury from IMH. METHODS:SHIELD-MI was a single-center, non-randomized, placebo-controlled, sequential-cohort phase IIa study with participants and the cardiac MRI (CMR) core laboratory blinded to treatment. Twenty-five patients received intravenous DXZ 250 mg before primary PCI and at 4, 8, and 12 h thereafter. Twenty-five comparators, selected from 78 placebo-treated patients, were matched on total ischemic time, culprit territory, and pre-PCI occlusion status. Primary endpoints were left ventricular ejection fraction (LVEF) and IMH volume on CMR at 48-72 h, evaluating early ventricular function and hemorrhagic myocardial injury after reperfusion. RESULTS:In the matched analytic cohort (n=50), LVEF was higher in patients receiving DXZ (39.8±7.7% vs. 34.7±10.1%; P=0.048), permitting formal testing of IMH volume, which was lower with DXZ (2.0±3.4% LV vs. 6.3±6.0% LV; P=0.004). The prespecified fixed-sequence criterion was therefore met at both steps. Infarct size was lower with DXZ (29.1±13.1% LV vs. 43.8±18.6% LV; P=0.002). Hemorrhagic MI occurred in 6/25 (24%) versus 16/25 (64%) participants (P=0.010). No drug-related serious adverse events were observed. CONCLUSIONS:Peri-procedural intravenous DXZ was associated with lower IMH and infarct size and higher LVEF, without safety concerns. These exploratory findings identify IMH as a candidate therapeutic target warranting a randomized trial.

Measuring cyclic changes in intramyocardial blood volume (iMBV) from systole to diastole has been used as an imaging marker for assessing coronary microcirculation and detecting coronary artery disease (CAD) without the need for vasodilator stress. However, an MRI-based method for detecting cyclic iMBV dynamics does not exist. The aim of this study is to demonstrate the feasibility of using ferumoxytol-enhanced (FE) MRI to detect systolic-to-diastolic iMBV dynamics on clinical scanners enabled by a new myocardial "T1 tracking" technique. To this end, a continuous steady-state sequence was developed, combining slice/slab-selective excitation, to generate high-resolution T1-weighted images such that the myocardial signal dynamically tracks the fractional volume of blood while minimizing the influence of confounding factors such as in-flow effects, through-plane motion, and spin history. In addition to phantom studies, FE studies in swine (n = 10) were conducted to generate systolic/diastolic T1 maps from the T1-tracking data. For comparison, MOLLI T1 maps were acquired. For both the T1-tracking method and MOLLI, T1 values before/after ferumoxytol were used to calculate iMBV at end-systole (ES) and end-diastole (ED). The T1-tracking method showed a significant iMBV difference between ES and ED (ES: 6.2 ± 1.8%, ED: 7.7 ± 2.0%, p < 10-3) as opposed to MOLLI (ES: 8.1 ± 2.9%, ED: 8.6 ± 3.1%, p = 0.4), and detected lower iMBV at ES vs. ED in all 10 studies, consistent with physiology, while MOLLI showed contradictory ES-to-ED change in 3 out of 10 studies. The proposed method showed a mean iMBV decrease of 19.1% from ED to ES, consistent with the nuclear imaging literature. In conclusion, the results show that the newly developed FE myocardial T1-tracking technique captures cyclic changes in iMBV, i.e., consistently reveals the expected drop in iMBV from diastole to systole, offering the potential to detect CAD without the need for pharmacological stress.

BACKGROUND:Quantitative coronary CT angiography plaque analysis (QCCTA) is a novel tool for atherosclerosis detection. OBJECTIVES:The authors examined utilization of a health plan offering of QCCTA to diabetic members and the impact of utilization on health plan costs. METHODS:Diabetic health plan members ≥40 years without prior myocardial infarction were offered QCCTA as a pilot benefit. Benefit utilizers were compared to eligible nonutilizers for incident cardiovascular episodes of care post-notification of eligibility. RESULTS:Over 14 months, 2,064 of 38,079 health plan members were identified as eligible. Utilizers (19.1%) were predominantly White (76.4%) and female (72.6%) residing in communities with high census median household income ($54,321 [$54,321-$71,159]). Utilizers' glycemic control was better (glycated hemoglobin 6.5% [6.0%-7.3%] vs 7.0% [6.4%-7.7%], P = 0.05), and 10-year atherosclerotic cardiovascular disease risk was lower (8.5% [4.2%-15.8%] vs 10.8% [5.7%-20.3%], P = 0.07). Detailed claims data from a matched cohort of 169 utilizers and 169 nonutilizers after a median of 19 months' follow-up showed more incident cardiovascular episodes of care in utilizers (1 [1-3] vs 1 [1-1], P < 0.0001) and higher incremental per-member per-month health plan expenditure for cardiovascular episodes of care ($19.04/month [4.65-85.11] vs $0/month [0-0], P < 0.0001). Per-member per-month was similar after adjusting for baseline glycated hemoglobin and atherosclerotic cardiovascular disease risk score (P = 0.78). CONCLUSIONS:Utilization of QCCTA offered to an employed population with diabetes varies by demographics while increasing near-term health plan expenditure for cardiovascular care. Longer-term studies are warranted to evaluate QCCTA's impact in value-based care models on diabetic members' health outcomes and total health plan spend.

Introduction Despite substantial reductions in early mortality achieved with primary percutaneous coronary intervention (PCI) in ST-elevation myocardial infarction (STEMI), intramyocardial hemorrhage (IMH) occurs in up to 40% of patients following reperfusion and is strongly associated with infarct expansion and adverse clinical outcomes. The determinants of IMH remain incompletely understood, particularly the roles of coronary anatomy and post-reperfusion hemodynamic forces. Objective We sought to determine whether angiographic features present before PCI and pressure dynamics within the distal coronary network are associated with IMH risk following reperfusion therapy. We hypothesized that coronary anatomy influences pressure redistribution during reperfusion and thereby modulates microvascular vulnerability to hemorrhagic injury. Methods Cardiac magnetic resonance imaging with late gadolinium enhancement (LGE) and T2* mapping was performed in 64 STEMI patients within 72 hours after PCI to assess infarction and IMH. Pre-PCI coronary angiograms were analyzed using a custom deep learning model designed to identify angiographic patterns associated with IMH. In a subset of 17 patients, patient-specific computational modeling based on a Navier–Stokes framework was used to simulate coronary pressure and flow under pre- and post-PCI conditions, explicitly incorporating collateral vessel anatomy. Results The deep learning model identified angiographic patterns associated with IMH, achieving an accuracy of 90.2%, a sensitivity of 91%, and an area under the receiver operating characteristic curve of 0.94. Hemodynamic simulations demonstrated that, in the absence of collateral circulation, reperfusion was associated with elevated distal pressures and steep pressure gradients. In contrast, collateral networks redistributed flow and attenuated distal pressure loading. These findings indicate that coronary anatomy and network topology influence pressure-dependent hemodynamic determinants relevant to IMH risk. Conclusions By integrating deep learning–based angiographic analysis with patient-specific hemodynamic modeling, this study reveals pressure-dependent determinants of intramyocardial hemorrhage following reperfusion therapy in STEMI patients. The results provide mechanistic insight into how coronary anatomy modulates distal vascular loading during reperfusion and support further investigation of pressure-aware approaches to mitigating microvascular injury.