A high prevalence of obstructive sleep apnea (OSA) has been reported in Down syndrome (DS) owing to the coexistence of multiple predisposing factors related to its genetic abnormality, posing a ...challenge for the management of OSA. We hypothesized that DS mice recapitulate craniofacial abnormalities and upper airway obstruction of human DS and can serve as an experimental platform for OSA research. This study, thus, aimed to quantitatively characterize the upper airway as well as craniofacial abnormalities in Dp(16)1Yey (Dp16) mice. Dp16 mice demonstrated craniofacial hypoplasia, especially in the ventral part of the skull and the mandible, and rostrally positioned hyoid. These changes were accompanied with a shorter length and smaller cross-sectional area of the upper airway, resulting in a significantly reduced upper airway volume in Dp16 mice. Our non-invasive approach, a combination of computational fluid dynamics and high-resolution micro-CT imaging, revealed a higher negative pressure inside the airway of Dp16 mice compared to wild-type littermates, showing the potential risk of upper airway collapse. Our study indicated that Dp16 mice can be a useful model to examine the pathophysiology of increased upper airway collapsibility of DS and to evaluate the efficacy of therapeutic interventions for breathing and sleep anomalies.
•Angiography-based fractional flow reserve (FFR) has a high correlation with wire-based FFR.•Clinical outcomes guided by angiography-based FFR are currently being investigated.•The index of ...microcirculatory resistance can be estimated by angiography by new technology.•Evidence of intravascular imaging-based FFR is rapidly growing.
Despite the current evidence supporting clinical benefits of fractional flow reserve (FFR), its uptake in the cardiac catheterization laboratory has been slow due to procedural cost and increased time with the need for maximum hyperemia. Recently, novel physiological indices derived from coronary angiography and intracoronary imaging have emerged to overcome issues with a wire-based FFR. Angiography-based FFR can be measured without vessel instrumentation and has shown excellent diagnostic performance using wire-based FFR as the reference standard. Thus, angiography-based FFR may facilitate coronary functional assessment before and after percutaneous coronary intervention (PCI). Angiography-based index of microcirculatory resistance (IMR) is another new computational index for assessing the coronary microcirculation. Although angiography-derived IMR remains in an early phase of development and requires further validation, its less-invasive nature may help broaden the adoption of microvascular functional assessment in various conditions such as myocardial infarction and cardiac allograft vasculopathy. Lastly, computational FFR based on intravascular ultrasound and optical coherence tomography allows detailed lesion assessment from both morphological and functional standpoints. Given a growing interest in physiology‐guided PCI optimization strategies, intravascular imaging-based FFR may become the main assessment tool to confirm successful PCI.
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Background:Long-term hepatic dysfunction is an increasingly recognized complication of the Fontan operation for univentricular hearts. The purpose of this study was to determine whether ...Fontan-associated liver disease (FALD) could be predicted by flow dynamics in the right atrium (RA) of Fontan circulation.Methods and Results:Cardiac MRI and the serum levels of total bilirubin (TBil) and hyaluronic acid (HA) were analyzed in 36 patients who underwent an atriopulmonary connection type of Fontan operation. The mean follow-up period was 53 months. Three views (axial, coronal, and sagittal) of the cine images were scanned for the maximum cross-section of the RA obtained with1.5-Tesla scanner. We developed a “vortex flow map” to demonstrate the ratio of the circumferential voxel movement in each phase to the total movement throughout a cardiac cycle towards the center of the RA. The maximum ratio was used as the magnitude of vortex flow (MVF%) in the 3 views of the RA cine imaging. Patients with coronal MVF ≥13.6% had significantly lower free rates of TBil ≥1.8 mg/dL than those with coronal MVF <13.6% (log-rank value=4.50; P<0.05; hazard ratio=4.54). Patients with sagittal MVF ≥14.0% had significantly lower free rates of HA ≥50 ng/mL than those with coronal MVF <14.0% (log-rank value=4.40; P<0.05; hazard ratio=4.12).Conclusions:A reduced vortex flow in the RA during the late phase of the Fontan operation was associated with the development of FALD. MVF can be used as an imaging biomarker to predict FALD.
The prognostic factors in patients with biventricular heart who underwent Fontan surgery remain unclear. This study wanted to assess the hypothesis that interventricular dyssynchrony evaluated by ...cardiac magnetic resonance imaging (MRI) can predict future cardiac events in patients with biventricular heart who have undergone Fontan surgery. We prospectively enrolled consecutive patients with biventricular Fontan circulation from 2003 to 2016, and performed protocolized cardiac MRI. We determined the stroke volume ratio (SVr) using the following formula to assess interventricular dyssynchrony: (stroke volume (SV) of the two whole ventricles)/(SV of the right ventricle + SV of the left ventricle), by tracing cine MRI data. If interventricular dyssynchrony existed, blood flowed and returned to each ventricle through the ventricular septal defect; therefore, the SVr in this instance should be less than 1.0. We enrolled 40 patients. SVr ranged from 0.81 to 1.0 (median 0.95). Low SVr (< 0.95) was associated with worse New York Heart Association functional class, longer QRS duration, right bundle branch block, low biventricular indexed stroke volume, and low biventricular ejection fraction. During the follow-up period (median 53.5 months), 10 cardiac events occurred (six cases of acute exacerbation of heart failure, three cases of supraventricular tachycardia, and one case of exacerbation of protein-losing enteropathy). Univariate analysis showed four clinical predictors: SVr < 0.95 hazard ratio (HR) 9.3, 95% confidential interval (CI) 1.7–171.5; biventricular ejection fraction < 0.45 (HR 9.4, 95% CI 2.2–65.3); left ventricular indexed end-diastolic volume > 73 mL/m
2
(HR 4.5, 95% CI 1.1–15.7); and the presence of the aorta directly arising from the right ventricular conus (HR 5.8, 95% CI 1.1–106). SVr derived from MRI can predict future cardiac events in Fontan patients with biventricular hearts.
To assess ventricular function and dyssynchrony using three-dimensional (3D) computed tomography (CT) strain in adult congenital heart disease (ACHD). We prospectively analyzed a multiphase cardiac ...CT data set for 22 adult patients with CHD, including 8 patients with congenital systemic right ventricle (RV) and 14 patients with repaired Tetralogy of Fallot (TOF). Eight patients had a cardiac pacemaker. Volume of Interest was drawn on a multiplanar reconstruction of the ventricle with strain overlay using a 3D-strain algorithm. Ventricular strain, inter- and intraventricular dyssynchrony, and right ventricle outflow tract (RVOT)–apex dyssynchrony were calculated. RVOT–apex dyssynchrony by ventriculography was also compared in 15 patients. Pulmonary ventricular strain, systemic ventricular strain, and septal wall strain were lower in ACHD patients than in the controls, and lower in the ACHD with pacing group than without pacing group as well. Maximum interventricular time difference and intraventricular time difference were longer than in ACHD than in the controls, and longer in the ACHD with pacing group than without pacing group as well. RVOT–apex delay was significantly longer in patients with a pacemaker than in those without a pacemaker (118.1 ± 31.9 ms vs. 76.1 ± 36.2 ms, p = 0.03). RVOT delay determined by 3D CT strain significantly correlated with that determined by ventriculography (Pearson r = 0.55, p = 0.03). 3D CT strain can detect reduced biventricular contraction and inter- and intraventricular and RVOT–apex mechanical dyssynchrony can be assessed in patients with ACHD.
•Strain analysis by feature tracking magnetic resonance imaging for 100 patients after Fontan procedure.•Prediction of major adverse cardiac events (MACE) at late phase of Fontan procedure.•Global ...longitudinal strain (GLS) and the dyssynchrony index for single ventricle.•GLS and the dyssynchrony index: independent predictors of MACE.•Incremental information for risk stratification.
The aim of this study was to determine whether major adverse cardiac events (MACE) during the late phase of the Fontan procedure could be predicted by strain measurements of single ventricles using cardiac magnetic resonance imaging with feature tracking (CMR-FT).
One hundred adolescent patients who underwent the Fontan procedure (mean age, 21 years) were examined retrospectively with CMR-FT to assess the systemic single-ventricle function. Vertical long-axis cine imaging was divided into six myocardial segments. Global longitudinal strain (GLS) was determined by averaging the peak strain values of each of the six segments. The dyssynchrony index was defined as the standard deviation of the time to peak strain for six segments. The primary outcome was MACE, defined as cardiac death and unscheduled hospitalization.
MACE occurred in 18 patients during a mean follow-up of 62 months. According to the multivariate logistic regression analysis results for potential predictor variables, GLS and the dyssynchrony index are independent predictors of MACE. Patients with GLS ≥11.8% had significantly higher MACE-free rates than did those with GLS <11.8% log-rank value, 14.15; p = 0.0002; hazard ratio, 6.82; 95% confidence interval (CI), 2.51–18.56. Patients with a dyssynchrony index <63.5 ms had significantly higher MACE-free rates than did those with dyssynchrony index ≥63.5 ms (log-rank value, 28.17; p < 0.0001; hazard ratio, 21.69; 95% CI, 6.96–67.56).
GLS and the dyssynchrony index found using CMR-FT are independent predictors of MACE for adolescent patients after the Fontan procedure and provide information regarding risk stratification beyond clinical parameters and biomarkers.
Little is known about the overall diagnostic performance of computational fractional flow reserve (FFR) derived from angiography (Angio-FFR), intravascular ultrasound (IVUS-FFR), and optical ...coherence tomography (OCT-FFR) to detect hemodynamically significant coronary artery disease. The present study aimed to evaluate the diagnostic performance of those novel physiologic indices using conventional FFR as the gold standard.
PubMed and Embase were searched in September 2021 for a systematic review and meta-analysis of studies assessing the diagnostic performance of invasive imaging-derived FFR. The primary outcomes were the summary sensitivity, specificity, correlation coefficients of each index.
A total of 6572 records were initially identified and 49 studies were included in the final analysis (7010 lesions from 36 studies for Angio-FFR, 305 lesions from 5 studies for IVUS-FFR, and 667 lesions from 8 studies for OCT-FFR). Invasive imaging-derived FFR had a high diagnostic performance to detect functionally significant coronary lesions using conventional FFR as the gold standard Angio-FFR, sensitivity 0.87 (95% CI 0.84–0.89), specificity 0.93 (95% CI 0.910.95); IVUS-FFR, sensitivity 0.90 (95% CI 0.84–0.94), specificity 0.95 (95% CI 0.90–0.98); OCT-FFR, sensitivity 0.85 (95% CI 0.78–0.91), specificity 0.93 (95% CI 0.89–0.95). The summary correlation coefficients of Angio-, IVUS-, and OCT-FFRs with wire-based FFR were 0.83 (95% CI 0.80–0.85), 0.85 (95% CI 0.79–0.91), and 0.80 (95% CI 0.74–0.86), respectively.
This meta-analysis demonstrated that computational FFR derived from invasive coronary imaging has clinically acceptable diagnostic performances irrespective of modalities, supporting their applicability to clinical practice.
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•Fractional flow reserve (FFR) can be computed based on coronary angiography, intravascular ultrasound, and OCT.•Computational FFR derived from those modalities has excellent diagnostic performance.•Invasive imaging-derived FFR may facilitate coronary functional assessment.
Objective
Although both obesity and body posture are important factors affecting end‐expiratory lung volume (EELV) and upper airway patency, the influence of those factors on EELV and the association ...between EELV and upper airway calibers are still unknown in mice. This study examined such interaction effects in obese mice to test the hypothesis that obese mice have decreased EELV accompanied by structural alterations of the upper airway.
Methods
A high‐resolution in vivo micro‐computed tomography was utilized to scan anesthetized lean and diet‐induced obese mice in the prone and supine positions, followed by quantifying lung volume and analyzing upper airway morphology.
Results
There was a statistically significant interaction between the effects of body weight and posture on both EELV (p = 0.0049, η
2 = 0.1041) and upper airway calibers (p = 0.0215, η
2 = 0.6304). In lean mice, EELV in the prone position was significantly larger than in the supine position (prone EELV = 193.22 ± 9.10 µl vs. supine EELV = 176.01 ± 10.91 µl; p = 0.0072), whereas obese mice did not have such an improvement in EELV in the prone position (prone EELV = 174.37 ± 20.23 µl vs. supine EELV = 183.39 ± 17.49 µl; p = 0.0981) and tended to have a smaller upper airway when EELV was low based on Spearman's correlation analysis.
Conclusions
These data indicate that obesity is an important factor compromising both EELV and upper airway calibers in a posture‐dependent manner even in mice, which should be taken into consideration in future studies regarding upper airway collapse and lung mechanical properties using mice.
This study examined effects of obesity and body posture on end‐expiratory lung volume and upper airway calibers in mice. The reduced chest wall compliance secondary to obesity diminished the advantageous effect of the prone position on lung mechanical properties. Obese mice had a smaller upper airway compared to lean mice when EELV was low.
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