Circulation: Cardiovascular Imaging最新文献

Background: Randomized trials of venous thrombolysis to prevent postthrombotic syndrome have produced mixed results. A method to identify patients most likely to benefit from interventional treatment is needed. This study evaluated a contrast-free, magnetic resonance-based multisequence thrombus imaging (MSTI) technique to characterize deep venous thrombi and predict susceptibility to thrombolysis.

Methods: Venous thrombosis was induced in the inferior vena cava of BALB/C mice (n=56, male), which were imaged up to 28 days postsurgery and 24 hours after systemic thrombolysis (Actilyse, 10 mg/kg, IV). The prelysis MSTI protocol included 3-dimensional T1 mapping, 3-dimensional magnetization transfer, and 2-dimensional diffusion-weighted imaging. Thrombolysis was defined as successful if inferior vena cava blood flow increased by ≥50% compared with prelysis values. In a clinical cohort, 41 patients with acute iliofemoral deep venous thrombi underwent MSTI before catheter-directed thrombolysis. Imaging parameters were analyzed against postintervention outcomes.

Results: MSTI identified thrombi susceptible to thrombolysis in both mice and humans. In mice, lysed thrombi showed lower T1 (723 [667-782] versus 874 [799-1000] ms; P<0.001) and higher apparent diffusion coefficient values (1.02 [0.96-1.14] versus 0.78 [0.62-0.88]×10^-³ mm²/s; P<0.001) than nonlysable thrombi, with no difference in magnetization transfer. In patients, lysed thrombi demonstrated lower T1 (606 [543-656] versus 765 [630-909] ms; P<0.001), lower apparent diffusion coefficient (0.67 [0.5-1.1] versus 1.23 [0.69-1.74]×10^-³ mm²/s; P=0.001), and similar magnetization transfer rates. Combining MSTI parameters optimized prediction, achieving 88% sensitivity and 97% specificity in mice, and 86% sensitivity and 91% specificity in humans.

Conclusions: MSTI enables noninvasive, contrast-free characterization of thrombus composition and predicts thrombolytic susceptibility. This technique has the potential to guide patient selection for invasive therapies and should be incorporated into future trials of venous thrombosis treatment.

Background: Absolute quantification of myocardial blood flow (MBF) on positron emission tomography perfusion imaging improves the identification of coronary artery disease (CAD). However, distinguishing MBF impairment due to obstructive CAD from nonobstructive CAD remains challenging. We aimed to evaluate the incremental diagnostic value of positron emission tomography derived relative flow reserve (RFR) in the diagnosis of obstructive CAD.

Methods: This is a post hoc analysis of the multicenter phase III trial of ¹⁸F-flurpiridaz positron emission tomography. Patients with available MBF quantification were included. Reduced stress MBF (sMBF) was defined as sMBF below the median (2.2 mL/min per gram). Obstructive CAD on quantitative invasive coronary angiography was defined as ≥70% stenosis. RFR was calculated as a ratio of the minimal segment sMBF over the highest reference vascular territory sMBF. RFR performance for predicting obstructive CAD was evaluated through receiver operating characteristic analysis and the net reclassification index of multivariable regression models.

Results: The study included 231 patients (71% male; 56% with established CAD) drawn from the original cohort of 755 trial participants. No patients had 3-vessel CAD. In a per-vessel-based analysis, 82% of vessels with reduced sMBF had no obstructive CAD on invasive coronary angiography. RFR was significantly lower for vessels with obstructive CAD (0.55 versus 0.80; P<0.0001). In vessels with reduced sMBF, RFR was independently associated with obstructive CAD even after accounting for stress total perfusion deficit and myocardial flow reserve (odds ratio, 3.08 [95% CI, 1.49-6.38]; P=0.002). Although the addition of RFR did not significantly improve discrimination (area under the curve, 0.806 versus 0.822; P=0.11), it significantly improved reclassification of vessels with and without obstructive CAD (net reclassification index, 0.93; obstructive CAD net reclassification index, 0.44; nonobstructive CAD net reclassification index, 0.49; P<0.0001).

Conclusions: RFR provides complementary diagnostic information beyond existing positron emission tomography parameters and may help refine the diagnosis of obstructive CAD in patients with reduced flows.

Registration: URL: https://clinicaltrials.gov; Unique identifier: NCT01347710.

Background: Psychosocial stress is linked to the development of cardiovascular disease, with a more pronounced impact in female participants. This study investigates sex differences in the association between perceived stress and myocardial tissue characteristics, as assessed by cardiovascular magnetic resonance imaging, and evaluates the contribution of psychosocial burden, including caregiving and perceived social standing.

Methods: This study included 219 participants (53.9% females; mean age, 54.4±11.0 years) without overt cardiovascular disease, drawn from a prospective repository. Participants completed the perceived stress scale and cardiovascular magnetic resonance with native T1 and T2 mappings. Psychosocial variables included family caregiving responsibilities and perceived emotional support. The study investigated associations between perceived stress scale scores, and native T1 and T2 mapping sequences and assessed sex differences and psychosocial burden.

Results: High-stress female participants had significantly longer T1 times than low-stress female participants in both healthy and at-risk groups and longer T2 times in the at-risk group. No significant differences were observed in male participants. Perceived stress scale scores significantly predicted T1 values in female participants (95% CI, 0.088-3.517; P=0.040) but not in male participants (94% CI, -0.687 to 2.139; P=0.310). In multivariable analysis, caregiving burden and perceived emotional support were independent predictors of T1 in female participants (P=0.009 and P=0.035, respectively) but not in male participants.

Conclusions: Psychosocial stress was associated with early subclinical myocardial changes in female participants but not in male participants, suggesting sex-specific pathways linking stress to early myocardial remodeling. These findings support the integration of psychosocial factors into cardiovascular risk assessment for female individuals.

Background: Coronary computed tomography angiography (CCTA) could evaluate myocardial fibrosis as well by estimating extracellular volume fraction (ECV). While coronary microvascular dysfunction (CMD) has been increasingly recognized as an important pathophysiological mechanism underlying chest pain, the association between CMD in angina with nonobstructive coronary artery disease (ANOCA) and CCTA-derived ECV remains to be elucidated. We sought to evaluate the association between CCTA-derived ECV and CMD in patients with ANOCA.

Methods: We retrospectively analyzed 57 patients with ANOCA from a single center who underwent CCTA on ECV protocol with subtraction method (including precontrast and 7-minute delayed postcontrast) and invasive functional testing using pressure-temperature sensor-tipped wire. Patients with significant epicardial stenosis (fractional flow reserve ≤0.80 or stenosis on computed tomography ≥50%), prior history of revascularization, known myocardial infarction, or heart failure were excluded. CMD was defined as a coronary flow reserve of <2.5 in any of the vessels evaluated. Standard transthoracic echocardiography assessed diastolic dysfunction (DD).

Results: Among the 57 patients included, 26 (45.6%) were diagnosed with CMD. CMD was significantly associated with age, NT-proBNP (N-terminal pro-B-type natriuretic peptide) level, calcium score, DD, and higher ECV. In a multivariable logistic regression analysis, a CCTA-derived ECV >31.9% (the optimal cutoff value derived from receiver operating characteristic curve analysis) was independently associated with CMD (odds ratio, 10.50 [95% CI, 2.34-47.40]; P=0.002). DD also emerged as an independent predictor (odds ratio, 17.90 [95% CI, 2.53-127.00]; P=0.004). The addition of elevated ECV to a clinical model including DD significantly enhanced the discrimination efficacy for CMD (area under the receiver operating characteristic curve, 0.742 versus 0.854; P=0.019).

Conclusions: In patients with ANOCA with CMD, ECV was significantly elevated, alongside a higher prevalence of DD. These findings suggest that ECV and DD may serve as pivotal markers for personalized management strategies in patients with CMD with ANOCA.

Background: In hypertrophic obstructive cardiomyopathy, left ventricular mass index (LVMi) regresses following septal myectomy, but the specific dynamics, mechanisms (involving cellular and extracellular compartments), and related factors remain unclear.

Methods: This prospective study included patients with hypertrophic obstructive cardiomyopathy who underwent septal myectomy. Cardiac magnetic resonance imaging was performed preoperatively and at 6, 12, and 24 months postoperatively. LVMi, indexed cellular volume, and indexed extracellular volume were analyzed using repeated measures ANOVA. Factors associated with LVMi regression, postoperatively, were identified using linear regression.

Results: The study included 27 patients (53.70±13.85 years; 17 female). LVMi significantly decreased from 105.76±25.22 g/m², preoperatively, to 82.52±25.90 g/m² at 6 months, postoperatively, further declining to 78.86±24.73 g/m² at 12 months and 76.22±23.93 g/m² at 24 months (P<0.05). The average percent decrease in LVMi from baseline was 22.97% at 6 months, 26.26% at 12 months, and 28.58% at 24 months postoperatively. This regression is primarily driven by indexed cellular volume regression (23.70%), with a smaller reduction in the indexed extracellular volume (18.40%) in the first 6 months. Both compartments exhibited sustained reductions through 12 months. But from 12 to 24 months, only indexed extracellular volume continued to decline (from 22.13±6.76 to 20.89±6.25 mL/m²; P<0.001). Greater left ventricular outflow tract pressure gradient reduction (β=0.157; P=0.001) was associated with LVMi regression after septal myectomy.

Conclusions: In patients with hypertrophic obstructive cardiomyopathy postseptal myectomy, early LVMi reduction involves both cellular and extracellular compartments, with slower reduction from 12 to 24 months, mainly driven by the extracellular component. This demonstrates rapid myocardial adaptability to afterload relief, with slower extracellular matrix remodeling. Greater left ventricular outflow tract pressure gradient reduction was associated with greater LVMi regression after surgery.

Registration: URL: https://www.chictr.org.cn; Unique identifier: ChiCTR2100043699.