Circulation: Cardiovascular Imaging最新文献

Right ventricular (RV) failure is a principal determinant of morbidity and mortality in children with pulmonary hypertension, making accurate RV assessment a cornerstone of risk stratification and long-term management. Noninvasive imaging plays a central role in this evaluation; however, commonly used modalities, including 2- and 3-dimensional echocardiography and cardiac magnetic resonance imaging, each have distinct advantages and limitations in the pediatric population. Consequently, an integrated, multimodal imaging strategy is required. This review provides a contemporary, critical appraisal of the existing evidence and key knowledge gaps related to noninvasive multimodality imaging of the RV in pediatric pulmonary hypertension. The discussion is structured around fundamental aspects of RV physiology, including chamber size and mass, systolic function, diastolic function and stiffness, RV-left ventricle interactions, ventriculoarterial coupling, and exercise assessment. Echocardiography and cardiac magnetic resonance imaging are presented in parallel to highlight their complementary roles within a multimodality framework. Current prognostic thresholds in pediatric pulmonary hypertension imaging are largely supported by level of evidence C, underscoring persistent gaps that limit the development of definitive clinical recommendations and a unified approach. We propose a roadmap to guide future research efforts and collaborative initiatives among pediatric pulmonary hypertension and imaging specialists, emphasizing the role of professional networks in advancing the field.

Background: Computed tomography based planimetric assessment of the anatomic aortic valve area (aAVA^CTA) in aortic stenosis is routinely performed. Unlike transthoracic echocardiography (TTE)-based effective AVA by TTE, it lacks clearly defined severity cutoff values, limiting clinical utility.

Methods: In this retrospective single-center analysis with computed tomography angiography data from 2013 to 2025, cutoffs were determined from 1294 TTE-based conclusive severe or nonsevere patients by congruence of maximum velocity, mean pressure gradient, and effective AVA by TTE. In separate receiver operator curves analyses for tricuspid and bicuspid valves, the severe stenosis likely cutoff was defined by Youden index and the unlikely cutoff by a negative likelihood ratio <0.1. Cutoffs were internally validated in 480 patients, compared with the Agatston score by net reclassification index, and tested in 190 separate normal-flow low-gradient aortic stenosis cases.

Results: Correlation between aAVA^CTA and effective AVA by TTE was moderate and strong in tricuspid and bicuspid valves, respectively (Pearson r 0.67 and 0.78; P<0.001). Severe stenosis was likely in tricuspid valves at aAVA^CTA ≤0.95 cm² (sensitivity 87%, specificity 78.9%) and unlikely at ≥1.10 cm² (negative likelihood ratio, 0.092). In bicuspid valves severe stenosis was likely at aAVA^CTA ≤1.08 cm² (sensitivity 88.3%, specificity 77.3%) and unlikely at ≥1.20cm² (negative likelihood ratio, 0.091). Validation showed comparable results. Net reclassification index compared with the Agatston score was 0.16 for likely and 0.17 for unlikely cutoffs (P<0.001). Cutoffs were applied to 190 suspected severe low-gradient cases. Adding aAVA^CTA as an additional severity marker led to reclassification to nonsevere in 5.8% of cases.

Conclusions: Direct planimetry of AVA is feasible and shows utility in low gradient-aortic stenosis. However, as the hemodynamic effect is impacted by valve shape, cutoff values should differentiate between tricuspid and bicuspid valves.

Background: Tricuspid regurgitation (TR) leads to systemic venous congestion and congestive hepatopathy, but conventional TR imaging parameters incompletely capture systemic consequences. Hepatic extracellular volume fraction (ECV) on cardiac magnetic resonance T1 mapping may reflect hepatic tissue remodeling and provide prognostic information beyond conventional risk markers.

Methods: Consecutive patients with moderate or greater TR who underwent cardiac magnetic resonance with hepatic T1 mapping were studied. Hepatic ECV was calculated using pre- and postcontrast T1 values and hematocrit. Patients were stratified by hepatic ECV tertiles. The primary end point was all-cause mortality.

Results: Among 234 patients (mean age, 65.6±15.8 years; 46.2% men), mean hepatic ECV was 37.7±9.0%, with tertile cutoffs at 32.5% and 41.3%. Higher hepatic ECV tertiles were associated with worse biventricular function and greater TR severity. Right ventricular ejection fraction decreased across tertiles (48.2% versus 48.5% versus 40.3%, P<0.001), while right ventricular end-diastolic volume index increased (107.4 versus 105.4 versus 127.4 mL/m², P<0.001). The prevalence of severe TR (regurgitant fraction ≥50%) increased from 10.9% (mean) across tertiles 1 and 2 to 29.5% in tertile 3 (P<0.001). During a mean follow-up of 2.2 years, 43 (18.4%) deaths occurred. Mortality increased across hepatic ECV tertiles: 12.8% versus 11.5% versus 30.8% (P=0.002 for trend). Kaplan-Meier analysis showed 3-year survival rates of 88%, 89%, and 57% across tertiles 1, 2, and 3, respectively. In multivariable Cox regression adjusting for age, right ventricular dysfunction, and severe TR, hepatic ECV tertiles remained independently predictive of mortality (hazard ratio, 1.62 [95% CI, 1.06-2.48]; P=0.027). Forward stepwise analysis yielded significant incremental prognostic value beyond traditional TR risk factors, improving model discrimination from χ²=24.4 to 30.1 (P=0.02).

Conclusions: Hepatic ECV is a novel prognostic marker that provides incremental risk stratification in TR and has potential to impact therapeutic decision-making in the era of expanded treatment options for TR.

Background: Physiologic interaction between the cardiovascular and renal systems is pivotal in the understanding of disease and as a target for therapeutic interventions, as highlighted in the cardiovascular-kidney-metabolic syndrome. This study explores the association of renal blood flow, derived noninvasively from cardiac positron emission tomography-computed tomography, with cardiovascular and renal outcomes.

Methods: We evaluated the association between renal blood flow and outcomes in a retrospective cohort of 295 consecutive patients who underwent ¹³N-ammonia positron emission tomography-computed tomography myocardial perfusion imaging between September 1, 2019, and March 1, 2020 (Brigham and Women's Hospital, Boston). Global myocardial blood flow, myocardial flow reserve, semiquantitative coronary artery calcium, and previously validated resting renal blood flow were obtained, along with clinical and laboratory data. Patients were followed for 4.0 (interquartile range, 1.7-4.1) years for a composite cardiovascular outcome of all-cause mortality, heart failure hospitalization, or acute coronary syndrome, and a composite renal outcome of 25% reduction in estimated glomerular filtration rate or end-stage renal disease. Survival analyses were adjusted for demographic and clinical characteristics and additionally for estimated glomerular filtration rate and myocardial flow reserve.

Results: The population had a mean age of 65.6 years, a body mass index of 29.2 kg/m², and was 49% female. Overall, 36% had chronic kidney disease stage ≥3. Patients were stratified into 3 renal blood flow groups: ≥75%, 25 to 75th, and ≤25% percentile. Lower renal blood flow was significantly associated with a higher risk of cardiovascular events (adjusted hazard ratio, 5.21 [95% CI 1.53-17.75]; P=0.008; lowest versus highest quartile), and with an elevated risk of adverse renal outcomes (P=0.026), independent of estimated glomerular filtration rate and myocardial flow reserve.

Conclusions: Impaired renal blood flow is associated with cardiac and kidney events, independent of the highly prognostic estimated glomerular filtration rate and myocardial flow reserve. Simultaneous quantification of cardiac and renal perfusion by noninvasive ¹³N-ammonia positron emission tomography-computed tomography may provide a valuable tool to interrogate pathophysiology and prognosis in the cardiovascular-kidney-metabolic syndrome.