Circulation: Cardiovascular Imaging最新文献

Background: Myocardial flow reserve (MFR), measured by positron emission tomography (PET) myocardial perfusion imaging, provides valuable information on epicardial coronary disease, diffuse atherosclerosis, and microvascular function. Despite its routine use, the prognostic efficacy of ¹³N-ammonia PET MFR remains unconfirmed in larger multicenter cohorts of patients with suspected or known coronary artery disease.

Methods: We considered patients from 5 sites in the REFINE PET (Registry of Fast Myocardial Perfusion Imaging With Next Generation PET) registry who underwent ¹³N-ammonia PET myocardial perfusion imaging for coronary artery disease. Clinical and imaging data were collected at the time of myocardial perfusion imaging. MFR was quantified as the ratio of stress to rest myocardial blood flow, using QPET software (Cedars-Sinai Medical Center, Los Angeles, CA). The primary outcome was all-cause mortality. Survival analyses were performed using Kaplan-Meier and Cox regression models adjusted for clinical and imaging covariates.

Results: In total, 6277 patients were included (median age of 65 years, 56% male). Median follow-up time was 3.8 years. There were 1895 patients with MFR ≤2 and 4382 with MFR >2. Patients with MFR ≤2 had significantly higher mortality than those with MFR >2 (n=701 [37.0%] versus n=537 [12.3%], respectively; P<0.001). Annualized all-cause mortality rates by MFR and summed stress score ranged from 1.7 to 15.8. In multivariable analysis, MFR ≤2 was independently associated with increased all-cause mortality in the overall population (hazard ratio, 2.70 [95% CI, 2.41-3.03]; P<0.001), even among patients with no perfusion defects (hazard ratio, 2.36 [95% CI, 1.93-2.89]; P<0.001). Mortality risk decreased across increasing MFR deciles, ranging from hazard ratio, 2.73 (95% CI, 2.39-3.11) to hazard ratio, 0.35 (95% CI, 0.25-0.50).

Conclusions: In this large multicenter cohort, MFR derived from ¹³N-ammonia PET myocardial perfusion imaging is a strong, independent predictor of all-cause mortality, even in patients with normal perfusion. An MFR of ≤2.0 identifies elevated risk, while higher values are associated with improved survival. These findings support the routine integration of MFR to enhance risk stratification in patients with suspected or known coronary artery disease.

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.

Background: Racial and ethnic differences have been reported for aortic valve calcium (AVC) and long-term aortic stenosis (AS). Whether these differences are due to differing risk factor profiles or the burden of AVC is unknown.

Methods: Baseline AVC was quantified using the Agatston method among 6812 MESA (Multi-Ethnic Study of Atherosclerosis) participants. AVC scores were not reported to participants. The primary outcome of long-term moderate or severe AS was adjudicated using standard clinical criteria. We calculated multivariable Cox proportional hazards with log-transformed AVC as a continuous variable for each race and ethnicity.

Results: The mean age was 62 years, and 47% of participants were women. Over a median follow-up of 16.7 years, 140 participants were diagnosed with moderate (n=56) and severe AS (n=84). The prevalence of baseline AVC >0 by self-reported race and ethnicity was White (15.8%), Hispanic (13.3%), Black (12.3%), and Chinese (8.3%). The rate of long-term incident moderate-severe AS was highest for White participants (2.1/1000 person-years) and lowest for Chinese participants (0.5/1000 person-years). The association of AVC with moderate-severe AS was significant for all race and ethnicity groups: White hazard ratio, 1.82 (95% CI, 1.62-2.03); Hispanic hazard ratio, 2.18 (95% CI, 1.82-2.62); Black hazard ratio, 2.28 (95% CI, 1.78-2.93); and Chinese hazard ratio, 3.65 (95% CI, 1.05-12.71) per 1 unit higher log transformed AVC. There was no interaction by race and ethnicity (P=0.26) when modeling Black versus non-Black participants.

Conclusions: The racial and ethnic groups with a higher baseline prevalence of AVC had a higher long-term incidence of moderate-severe AS, but a similar relative association between AVC and moderate-severe AS regardless of baseline atherosclerotic cardiovascular disease risk. Our findings suggest that differences in AS by race and ethnicity may likely be explained by the burden of AVC.

Background: Computed tomography based planimetric assessment of the anatomic aortic valve area (aAVA^CTA) in aortic stenosis is routinely performed. Unlike transthoracic echocardiography-based effective AVA by transthoracic echocardiography, 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 transthoracic echocardiography-based conclusive severe or nonsevere patients by congruence of maximum velocity, mean pressure gradient, and effective AVA by transthoracic echocardiography. 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 transthoracic echocardiography 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 (HR, 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.

Heart failure with preserved ejection fraction (HFpEF) is a multifaceted syndrome that often presents diagnostic challenges due to its diverse causes and overlapping symptoms with other conditions. Its prevalence is increasing, driven by an aging population and rising associated comorbidities including obesity, diabetes, and hypertension. Echocardiography is a cornerstone in the screening and diagnosis of HFpEF due to its noninvasive nature, accessibility, and ability to provide a comprehensive cardiac assessment. Cardiac magnetic resonance can further enhance diagnostic accuracy and be a useful tool in follow-up. Cardiac magnetic resonance tissue characterization by parametric mapping sequences (T1/T2 mapping, late gadolinium enhancement, extracellular volume quantification, myocardial flow reserve, and myocardial strain) is also helpful in evaluating specific conditions that can lead to symptoms of heart failure in the setting of normal ejection fraction. The role of cardiac magnetic resonance has become increasingly important with the emergence of new therapies, as distinguishing HFpEF causes is essential for precise therapy selection. In this review, we describe the diagnostic imaging features associated with HFpEF, along with the potential role of imaging in follow-up. We also propose a diagnostic workflow for suspected HFpEF cases in clinical practice.