Circulation: Cardiovascular Imaging最新文献

Background: Accurate aortic stenosis (AS) phenotyping requires multimodality imaging which has limited availability. The digital aortic stenosis severity index (DASSi), an AI biomarker of AS-related remodeling on single-view 2-dimensional echocardiography, predicts AS progression independent of Doppler measurements. We sought to evaluate the ability of DASSi to define personalized AS progression profiles and to validate its performance as a scalable alternative to multimodality imaging features of functional, structural, and biological AS severity.

Methods: In the SALTIRE-2 trial (Study Investigating the Effect of Drugs Used to Treat Osteoporosis on the Progression of Calcific Aortic Stenosis 2) of participants with mild or moderate AS, we performed blinded DASSi measurements (probability of severe AS, 0-1) on baseline transthoracic echocardiograms. We evaluated the association between baseline DASSi and (1) disease severity by hemodynamic (peak aortic valve velocity), structural (computed tomography-derived aortic valve calcium score), and biological features ([¹⁸F]sodium fluoride uptake on positron emission tomography-computed tomography); (2) longitudinal disease progression (change in peak aortic valve velocity and aortic valve calcium score); and (3) incident aortic valve replacement. We used generalized linear mixed or Cox models adjusted for risk factors and aortic valve area.

Results: We analyzed 134 participants (72 [IQR, 69-78] years; 27 [20.1%] women) with a mean baseline DASSi of 0.51 (SD, 0.19). DASSi was independently associated with cross-sectional disease severity: each SD increase was associated with higher peak aortic valve velocity (+0.21 [95% CI, 0.12-0.30] m/s), aortic valve calcium score (+284 [95% CI, 101-467] Agatston units), and [¹⁸F]sodium fluoride target-to-background ratio_max (+0.17 [95% CI, 0.04-0.31]). Higher DASSi was also associated with disease progression by Doppler (peak aortic valve velocity) and computed tomography (aortic valve calcium score) at 24 months (P interaction for DASSi × time<0.001), and future aortic valve replacement (75 events over 5.5 [IQR, 2.4-7.2] years, adjusted HR, 1.42 [95% CI, 1.11-1.84] per SD).

Conclusions: DASSi is associated with functional, structural and biological features of AS severity and predicts disease progression and adverse outcomes. DASSi-enhanced echocardiography may provide an accessible alternative to multimodality AS imaging and serve as a predictive enrichment biomarker in clinical trials.

Registration: URL: https://www.clinicaltrials.gov; Unique identifier: NCT02132026.

Background: This study aims to develop a diffusion model-based framework for generating late gadolinium enhancement (LGE)-like images without contrast. The resulting synthetic images are then comprehensively evaluated for subjective and objective image quality, as well as their clinical utility for quantifying scar in acute myocardial infarction.

Methods: In this retrospective study, we developed a diffusion mode-based framework, multisequence guided diffusion to generate synthetic native enhancement (SNE) images from cine magnetic resonance imaging, and T2 short tau inversion recovery sequences. Data were collected from 331 patients with acute myocardial infarction across 3 centers from January 2014 to July 2024. Subjective and objective image qualities were assessed using Likert scoring and contrast ratio analyses on both internal and external cohorts, comparing SNE with standard LGE to evaluate group differences. Myocardial contours were manually delineated, and scar size and transmurality were quantified using the full-width at half-maximum method to assess the accuracy of myocardial infarction detection.

Results: In comparisons with general generative models and multimodal fusion-based generative approaches, multisequence guided diffusion demonstrated more favorable visual perceptual quality and the closest data distribution alignment to conventional LGE. SNE demonstrated significantly higher quality than LGE (internal: 4.250 [4.000-4.750] versus 4.000 [3.750-4.500]; external: 4.250 [4.000-4.750] versus 4.000 [3.500-4.250]; P<0.05) and improved contrast ratios (blood pool versus myocardium: 9.010 [6.938-12.761] versus 8.767 [6.361-11.745] internally and 16.871 [12.546-24.237] versus 13.472 [9.380-19.599] externally; P<0.05). SNE showed strong agreement with LGE for scar size (internal R=0.839; external R=0.816; P<0.001) and transmurality (internal R=0.792; external R=0.758; P<0.001) with minimal biases (scar size: 2.490% internal, 2.222% external; transmurality: 2.984% internal, 2.225% external), indicating accurate scar depiction and robust generalizability.

Conclusions: SNE demonstrated strong agreement with LGE in quantitative assessment of acute myocardial infarction scar, with comparable or improved image quality.

Background: Contractile reserve assessment assesses myocardial performance and prognosis. The microstructural mechanisms that facilitate increased cardiac function have not been described, but can be studied using diffusion tensor cardiovascular magnetic resonance. Resting microstructural contractile function is characterized by reorientation of aggregated cardiomyocytes (sheetlets) from wall-parallel in diastole to a more wall-perpendicular configuration in systole, with the diffusion tensor cardiovascular magnetic resonance parameter E2A defining their orientation, and sheetlet mobility defining the angle through which they rotate. We used diffusion tensor cardiovascular magnetic resonance to identify the microstructural response to dobutamine stress in healthy volunteers and then compared with patients with recovered dilated cardiomyopathy (rDCM).

Methods: In this first-of-its-kind prospective observational study, 20 healthy volunteers and 32 patients with rDCM underwent diffusion tensor cardiovascular magnetic resonance at rest, during dobutamine, and on recovery.

Results: In healthy volunteers, both diastolic and systolic E2A increased with dobutamine stress (13±3° to 17±5°; P<0.001 and 59±11° to 65±7°; P=0.002). Sheetlet mobility remained unchanged (45±11° to 49±10°; P=0.19), but biphasic mean E2A increased (36±6° to 41±4°; P<0.001). In rDCM, diastolic E2A at rest was higher than in healthy volunteers (20±8° versus 13±3°, P<0.001), and sheetlet mobility was reduced (34±12° versus 45±11°; P<0.001). During dobutamine stress, rDCM diastolic and systolic E2A increased compared with rest (20±8° to 24±10°; P=0.001 and 54±13° to 63±11°; P=0.005). However, sheetlet mobility in patients with rDCM failed to increase with dobutamine to healthy levels (39±13° versus 49±10°; P=0.005).

Conclusions: This is the first report describing how the myocardial microstructure facilitates cardiac reserve. In health, sheetlet mobility moves further toward the wall-perpendicular plane to drive increased contractility, rather than increased magnitude of sheetlet mobility. Despite clinical recovery in patients with rDCM, microstructural function at rest and during dobutamine remains impaired. Further understanding of microstructural remodeling at rest and during stress may help refine risk stratification of patients with rDCM at risk of relapse.

Background: Lp(a) (lipoprotein [a]) and coronary artery calcium score (CACS) are independently associated with atherosclerotic cardiovascular disease (ASCVD) risk. This study aimed to investigate sex-specific prognostic differences between Lp(a) and CACS in ASCVD risk.

Methods: We analyzed 4651 participants from the Multi-Ethnic Study of Atherosclerosis, grouped by sex. Multivariable Cox regression analysis was performed to evaluate the prognostic value of Lp(a) and CACS for ASCVD risk in both sexes. The predictive performance of these factors was compared in men and women.

Results: During a median follow-up of 13.84 years, 465 ASCVD events were recorded (272 in men and 193 in women). Multivariable Cox regression analysis revealed that both elevated Lp(a) and CACS were independent predictors of ASCVD risk in both sexes. The C-index analysis demonstrated that CACS provided incremental prognostic value over Lp(a) in men (C-index: 0.732 versus 0.714; P=0.011), but not in women (C-index: 0.776 versus 0.762; P=0.069). Notably, in men with CACS >400, elevated Lp(a) levels (adjusted hazard ratio, 1.822 [95% CI, 1.041-3.189]; P=0.036) were associated with higher ASCVD risk, although no such association was observed in those with CACS ≤400. In women, elevated Lp(a) levels were associated with increased ASCVD risk in those with CACS >100 (adjusted hazard ratio, 1.877 [95% CI, 1.130-3.118]; P=0.015).

Conclusions: Although both Lp(a) and CACS independently predict ASCVD risk in both sexes, the predictive value of Lp(a) varies significantly between men and women across different CACS categories. These findings may inform sex-specific strategies for primary prevention of ASCVD.