Publications by authors named "Yousef Arar"

12 Publications

  • Page 1 of 1

Fick versus flow: a real-time invasive cardiovascular magnetic resonance (iCMR) reproducibility study.

J Cardiovasc Magn Reson 2021 Jul 19;23(1):95. Epub 2021 Jul 19.

Department of Pediatrics, University of Texas Southwestern Medical Center, Dallas, TX, USA.

Background: Cardiac catheterization and cardiovascular magnetic resonance (CMR) imaging have distinct diagnostic roles in the congenital heart disease (CHD) population. Invasive CMR (iCMR) allows for a more thorough assessment of cardiac hemodynamics at the same time under the same conditions. It is assumed but not proven that iCMR gives an incremental value by providing more accurate flow quantification.

Methods: Subjects with CHD underwent real-time 1.5 T iCMR using a passive catheter tracking technique with partial saturation pulse of 40° to visualize the gadolinium-filled balloon, CMR-conditional guidewire, and cardiac structures simultaneously to aid in completion of right (RHC) and left heart catheterization (LHC). Repeat iCMR and catheterization measurements were performed to compare reliability by the Pearson (PCC) and concordance correlation coefficients (CCC).

Results: Thirty CHD (20 single ventricle and 10 bi-ventricular) subjects with a median age and weight of 8.3 years (2-33) and 27.7 kg (9.2-80), respectively,  successfully underwent iCMR RHC and LHC. No catheter related complications were encountered. Time taken for first pass RHC and LHC/aortic pull back was 5.1, and 2.9 min, respectively. Total success rate to obtain required data points to complete Fick principle calculations for all patients was 321/328 (98%). One patient with multiple shunts was an outlier and excluded from further analysis. The PCC for catheter-derived pulmonary blood flow (Qp) (0.89, p < 0.001) is slightly lower than iCMR-derived Qp (0.96, p < 0.001), whereas catheter-derived systemic blood flow (Qs) (0.62, p = < 0.001) was considerably lower than iCMR-derived Qs (0.94, p < 0.001). CCC agreement for Qp at baseline (C1-CCC = 0.65, 95% CI 0.41-0.81) and retested conditions (C2-CCC = 0.78, 95% CI 0.58-0.89) were better than for Qs at baseline (C1-CCC = 0.22, 95% CI - 0.15-0.53) and retested conditions (C2-CCC = 0.52, 95% CI 0.17-0.76).

Conclusion: This study further validates hemodynamic measurements obtained via iCMR. iCMR-derived flows have considerably higher test-retest reliability for Qs. iCMR evaluations allow for more reproducible hemodynamic assessments in the CHD population.
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http://dx.doi.org/10.1186/s12968-021-00784-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8287667PMC
July 2021

Echocardiographic Diagnosis of Double-Chambered Left Ventricle in an Infant.

CASE (Phila) 2021 Apr 2;5(2):115-118. Epub 2021 Feb 2.

Division of Pediatric Cardiology, Department of Pediatrics, University of Texas Southwestern, Dallas, Texas.

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http://dx.doi.org/10.1016/j.case.2020.12.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8071822PMC
April 2021

Feasibility and safety of quantitative adenosine stress perfusion cardiac magnetic resonance imaging in pediatric heart transplant patients with and without coronary allograft vasculopathy.

Pediatr Radiol 2021 Jul 1;51(8):1311-1321. Epub 2021 Apr 1.

Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX, 75390, USA.

Background: Pediatric heart transplant patients require cardiac catheterization to monitor for coronary allograft vasculopathy. Cardiac catheterization has no safe and consistent method for measuring microvascular disease. Stress perfusion cardiac magnetic resonance imaging (MRI) assessing microvascular disease has been performed in adults.

Objective: To investigate the feasibility and safety of performing cardiac MRI with quantitative adenosine stress perfusion testing in pediatric heart transplant patients with and without coronary allograft vasculopathy.

Materials And Methods: All pediatric heart transplant patients with coronary vasculopathy at our institution were asked to participate. Age- and gender-matched pediatric heart transplant patients without vasculopathy were recruited for comparison. Patients underwent cardiac MRI with adenosine stress perfusion testing.

Results: Sixteen pediatric heart transplant patients, ages 6-22 years, underwent testing. Nine patients had vasculopathy by angiography. No heart block or other complications occurred during the study. The myocardial perfusion reserve for patients with vasculopathy showed no significant difference with comparison patients (median: 1.43 vs. 1.48; P=0.49). Values for both groups were lower than expected values based on previous adult studies. The patients were also analyzed for time after transplant and the number of rejection episodes. Patients within 6 years of transplantation had a nonsignificant trend toward a higher myocardial perfusion reserve (median: 1.57) versus patients with older transplants (median: 1.47; P=0.46). Intra- and interobserver reproducibility were 97% and 92%, respectively.

Conclusion: Myocardial perfusion reserve is a safe and feasible method for estimating myocardial perfusion in pediatric heart transplant patients. There is no reliable way to monitor microvascular disease in pediatric patients. This method shows potential and deserves investigation in a larger cohort.
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http://dx.doi.org/10.1007/s00247-021-04977-1DOI Listing
July 2021

Lymphatic pathway evaluation in congenital heart disease using 3D whole-heart balanced steady state free precession and T2-weighted cardiovascular magnetic resonance.

J Cardiovasc Magn Reson 2021 03 1;23(1):16. Epub 2021 Mar 1.

Department of Pediatrics, Division of Pediatric Cardiology, University of Texas Southwestern Medical Center, Dallas Children's Medical Center, Dallas, TX, USA.

Background: Due to passive blood flow in palliated single ventricle, central venous pressure increases chronically, ultimately impeding lymphatic drainage. Early visualization and treatment of these malformations is essential to reduce morbidity and mortality. Cardiovascular magnetic resonance (CMR) T2-weighted lymphangiography (T2w) is used for lymphatic assessment, but its low signal-to-noise ratio may result in incomplete visualization of thoracic duct pathway. 3D-balanced steady state free precession (3D-bSSFP) is commonly used to assess congenital cardiac disease anatomy. Here, we aimed to improve diagnostic imaging of thoracic duct pathway using 3D-bSSFP.

Methods: Patients underwent CMR during single ventricle or central lymphatic system assessment using T2w and 3D-bSSFP. T2w parameters included 3D-turbo spin echo (TSE), TE/TR = 600/2500 ms, resolution = 1 × 1 × 1.8 mm, respiratory triggering with bellows. 3D-bSSFP parameters included electrocardiogram triggering and diaphragm navigator, 1.6 mm isotropic resolution, TE/TR = 1.8/3.6 ms. Thoracic duct was identified independently in T2w and 3D-bSSFP images, tracked completely from cisterna chyli to its drainage site, and classified based on severity of lymphatic abnormalities.

Results: Forty-eight patients underwent CMR, 46 of whom were included in the study. Forty-five had congenital heart disease with single ventricle physiology. Median age at CMR was 4.3 year (range 0.9-35.1 year, IQR 2.4 year), and median weight was 14.4 kg (range, 7.9-112.9 kg, IQR 5.2 kg). Single ventricle with right dominant ventricle was noted in 31 patients. Thirty-eight patients (84%) were status post bidirectional Glenn and 7 (16%) were status post Fontan anastomosis. Thoracic duct visualization was achieved in 45 patients by T2w and 3D-bSSFP. Complete tracking to drainage site was attained in 11 patients (24%) by T2w vs 25 (54%) by 3D-bSSFP and in 28 (61%) by both. Classification of lymphatics was performed in 31 patients.

Conclusion: Thoracic duct pathway can be visualized by 3D-bSSFP combined with T2w lymphangiography. Cardiac triggering and respiratory navigation likely help retain lymphatic signal in the retrocardiac area by 3D-bSSFP. Visualizing lymphatic system leaks is challenging on 3D-bSSFP images alone, but 3D-bSSFP offers good visualization of duct anatomy and landmark structures to help plan interventions. Together, these sequences can define abnormal lymphatic pathway following single ventricle palliative surgery, thus guiding lymphatic interventional procedures.
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http://dx.doi.org/10.1186/s12968-021-00707-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7919323PMC
March 2021

Interventional Cardiovascular Magnetic Resonance Imaging (iCMR) in an Adolescent with Pulmonary Hypertension.

Medicina (Kaunas) 2020 Nov 24;56(12). Epub 2020 Nov 24.

Division of Cardiology, Department of Pediatrics, Baylor College of Medicine, Texas Children's Hospital, Austin Specialty Care, Austin, TX 78759, USA.

The interventional cardiac magnetic resonance imaging (iCMR) catheterization procedure is feasible and safe for children and adults with pulmonary hypertension and congenital heart defects (CHD). With iCMR, the calculation of pulmonary vascular resistance (PVR) in children with complex CHD with multilevel shunt lesions is accurate. In this paper, we describe the role of the MRI-guided right-sided cardiac catheterization procedure to accurately estimate PVR in the setting of multiple shunt lesions (ventricular septal defect and patent ductus arteriosus) and to address the clinical question of operability in an adolescent with trisomy 21 and severe pulmonary hypertension.
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http://dx.doi.org/10.3390/medicina56120636DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7760170PMC
November 2020

MRI for Guided Right and Left Heart Cardiac Catheterization: A Prospective Study in Congenital Heart Disease.

J Magn Reson Imaging 2021 05 6;53(5):1446-1457. Epub 2020 Nov 6.

School of Biomedical Engineering and Imaging Sciences, King's College London, London, UK.

Background: Improvements in outcomes for patients with congenital heart disease (CHD) have increased the need for diagnostic and interventional procedures. Cumulative radiation risk is a growing concern. MRI-guided interventions are a promising ionizing radiation-free, alternative approach.

Purpose: To assess the feasibility of MRI-guided catheterization in young patients with CHD using advanced visualization passive tracking techniques.

Study Type: Prospective.

Population: A total of 30 patients with CHD referred for MRI-guided catheterization and pulmonary vascular resistance analysis (median age/weight: 4 years / 15 kg).

Field Strength/sequence: 1.5T; partially saturated (pSAT) real-time single-shot balanced steady-state free-precession (bSSFP) sequence.

Assessment: Images were visualized by a single viewer on the scanner console (interactive mode) or using a commercially available advanced visualization platform (iSuite, Philips). Image quality for anatomy and catheter visualization was evaluated by three cardiologists with >5 years' experience in MRI-catheterization using a 1-5 scale (1, poor, 5, excellent). Catheter balloon signal-to-noise ratio (SNR), blood and myocardium SNR, catheter balloon/blood contrast-to-noise ratio (CNR), balloon/myocardium CNR, and blood/myocardium CNR were measured. Procedure findings, feasibility, and adverse events were recorded. A fraction of time in which the catheter was visible was compared between iSuite and the interactive mode.

Statistical Tests: T-test for numerical variables. Wilcoxon signed rank test for categorical variables.

Results: Nine patients had right heart catheterization, 11 had both left and right heart catheterization, and 10 had single ventricle circulation. Nine patients underwent solely MRI-guided catheterization. The mean score for anatomical visualization and contrast between balloon tip and soft tissue was 3.9 ± 0.9 and 4.5 ± 0.7, respectively. iSuite provided a significant improvement in the time during which the balloon was visible in relation to interactive imaging mode (66 ± 17% vs. 46 ± 14%, P < 0.05).

Data Conclusion: MRI-guided catheterizations were carried out safely and is feasible in children and adults with CHD. The pSAT sequence offered robust and simultaneous high contrast visualization of the catheter and cardiac anatomy.

Level Of Evidence: 2 TECHNICAL EFFICACY STAGE: 1.
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http://dx.doi.org/10.1002/jmri.27426DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8247035PMC
May 2021

Transcatheter mechanical manipulation of obstructed prosthetic mitral valve in an infant.

Cardiol Young 2020 Nov 3;30(11):1747-1749. Epub 2020 Sep 3.

Department of Pediatrics, Division of Pediatric Cardiology, University of Texas Southwestern Medical Center, Dallas, TX75390.

Prosthetic valve thrombosis is a serious complication of prosthetic heart valves that typically requires either surgical intervention or systemic thrombolysis. In patients with contraindications to both treatment modalities, options can be limited. We describe an alternative approach to managing prosthetic valve thrombosis in an infant presenting in extremis with pulmonary haemorrhage. Using transoesophageal echocardiography and fluoroscopic guidance, we restored function to the infant's obstructed St. Jude prosthetic mitral valve through percutaneous transcatheter manipulation of the valve's leaflets.
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http://dx.doi.org/10.1017/S104795112000270XDOI Listing
November 2020

3D advanced imaging overlay with rapid registration in CHD to reduce radiation and assist cardiac catheterisation interventions.

Cardiol Young 2020 May 15;30(5):656-662. Epub 2020 Apr 15.

Pediatric Cardiology, Department of Pediatrics, UT Southwestern Children's Medical Center, Dallas, TX, USA.

Novel commercially available software has enabled registration of both CT and MRI images to rapidly fuse with X-ray fluoroscopic imaging. We describe our initial experience performing cardiac catheterisations with the guidance of 3D imaging overlay using the VesselNavigator system (Philips Healthcare, Best, NL). A total of 33 patients with CHD were included in our study. Demographic, advanced imaging, and catheterisation data were collected between 1 December, 2016 and 31 January, 2019. We report successful use of this technology in both diagnostic and interventional cases such as placing stents and percutaneous valves, performing angioplasties, occlusion of collaterals, and guidance for lymphatic interventions. In addition, radiation exposure was markedly decreased when comparing our 10-15-year-old coarctation of the aorta stent angioplasty cohort to cases without the use of overlay technology and the most recently published national radiation dose benchmarks. No complications were encountered due to the application of overlay technology. 3D CT or MRI overlay for CHD intervention with rapid registration is feasible and aids decisions regarding access and planned angiographic angles. Operators found intraprocedural overlay fusion registration using placed vessel guidewires to be more accurate than attempts using bony structures.
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http://dx.doi.org/10.1017/S1047951120000712DOI Listing
May 2020

Invasive cardiovascular magnetic resonance (iCMR) for diagnostic right and left heart catheterization using an MR-conditional guidewire and passive visualization in congenital heart disease.

J Cardiovasc Magn Reson 2020 03 26;22(1):20. Epub 2020 Mar 26.

Department of Pediatrics, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, TX, 75390, USA.

Background: Today's standard of care, in the congenital heart disease (CHD) population, involves performing cardiac catheterization under x-ray fluoroscopy and cardiac magnetic resonance (CMR) imaging separately. The unique ability of CMR to provide real-time functional imaging in multiple views without ionizing radiation exposure has the potential to be a powerful tool for diagnostic and interventional procedures. Limiting fluoroscopic radiation exposure remains a challenge for pediatric interventional cardiologists. This pilot study's objective is to establish feasibility of right (RHC) and left heart catheterization (LHC) during invasive CMR (iCMR) procedures at our institution in the CHD population. Furthermore, we aim to improve simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures.

Methods: Subjects with CHD were enrolled in a pilot study for iCMR procedures at 1.5 T with an MR-conditional guidewire. The CMR area is located adjacent to a standard catheterization laboratory. Using the interactive scanning mode for real-time control of the imaging location, a dilute gadolinium-filled balloon-tip catheter was used in combination with an MR-conditional guidewire to obtain cardiac saturations and hemodynamics. A recently developed catheter tracking technique using a real-time single-shot balanced steady-state free precession (bSSFP), flip angle (FA) 35-45°, echo time (TE) 1.3 ms, repetition time (TR) 2.7 ms, 40° partial saturation (pSAT) pre-pulse was used to visualize the gadolinium-filled balloon, MR-conditional guidewire, and cardiac structures simultaneously. MR-conditional guidewire visualization was enabled due to susceptibility artifact created by distal markers. Pre-clinical phantom testing was performed to determine the optimum imaging FA-pSAT combination.

Results: The iCMR procedure was successfully performed to completion in 31/34 (91%) subjects between August 1st, 2017 to December 13th, 2018. Median age and weight were 7.7 years and 25.2 kg (range: 3 months - 33 years and 8 - 80 kg). Twenty-one subjects had single ventricle (SV) anatomy: one subject was referred for pre-Glenn evaluation, 11 were pre-Fontan evaluations and 9 post-Fontan evaluations for protein losing enteropathy (PLE) and/or cyanosis. Thirteen subjects had bi-ventricular (BiV) anatomy, 4 were referred for coarctation of the aorta (CoA) evaluations, 3 underwent vaso-reactivity testing with inhaled nitric oxide, 3 investigated RV volume dimensions, two underwent branch PA stenosis evaluation, and the remaining subject was status post heart transplant. No catheter related complications were encountered. Average time taken for first pass RHC, LHC/aortic pull back, and to cross the Fontan fenestration was 5.2, 3.0, and 6.5 min, respectively. Total success rate to obtain required data points to complete Fick principle calculations for all patients was 331/337 (98%). Subjects were transferred to the x-ray fluoroscopy lab if further intervention was required including Fontan fenestration device closure, balloon angioplasty of pulmonary arteries/conduits, CoA stenting, and/or coiling of aortopulmonary (AP) collaterals. Starting with subject #10, an MR-conditional guidewire was used in all subsequent subjects (15 SV and 10 BiV) with a success rate of 96% (24/25). Real-time CMR-guided RHC (25/25 subjects, 100%), retrograde and prograde LHC/aortic pull back (24/25 subjects, 96%), CoA crossing (3/4 subjects, 75%) and Fontan fenestration test occlusion (2/3 subjects, 67%) were successfully performed in the majority of subjects when an MR-conditional guidewire was utilized.

Conclusion: Feasibility for detailed diagnostic RHC, LHC, and Fontan fenestration test occlusion iCMR procedures in SV and BiV pediatric subjects with complex CHD is demonstrated with the aid of an MR-conditional guidewire. A novel real-time pSAT GRE sequence with optimized FA-pSAT angle has facilitated simultaneous visualization of the catheter balloon tip, MR-conditional guidewire, and cardiac/vessel anatomy during iCMR procedures.
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http://dx.doi.org/10.1186/s12968-020-0605-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7098096PMC
March 2020

Novel markers predict death and organ failure following hemorrhagic shock.

Clin Chim Acta 2015 Feb 7;440:87-92. Epub 2014 Nov 7.

Department of Pathology, University Texas Health Science Center at San Antonio, 7704 Floyd Curl Drive, San Antonio, TX, United States.

Background: ADAMTS 13, sP-Selectin and HSP27 have been investigated as potential prognostic markers in patients with hemorrhagic shock.

Methods: This study was part of a double-blind, randomized, parallel-group, controlled trial and included seventeen trauma patients presented to ED with severe hemorrhagic. The sera for testing were collected from these patients at the time of admission. Investigators and laboratory personnel performing testing were blinded to the patients' identity and clinical course.

Results: The prognostic value of ADAMTS13, sP-Selectin, and HSP27 was compared to prognostic value of systolic blood pressure (SBP), base deficit estimation (BD), heart rate (HR), shock index (SI) and tissue oxygen saturation (StO2) by constructing the receiver operation characteristics (ROC). The area under the curve (AUC) of the ROC for HSP27 (0.92) was greater than for SBP (0.45), BD (0.89), HR (0.61), SI (0.45) and StO2 (0.46). AUC for sP-Selectin (0.86) and for ADAMTS13 antigen (0.74) were comparable with BD one, but greater than for the rest of currently used tests.

Conclusion: Serum concentrations of ADAMTS13, HSP27 and sP-Selectin measured during the admission, appear to be comparable to or better than SBP, BD, SI, HR and StO2 in predicting MODS and death after hemorrhage from trauma. These potential new markers deserve further investigation.
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http://dx.doi.org/10.1016/j.cca.2014.10.045DOI Listing
February 2015

Natural history and clinical implications of nondepressed skull fracture in young children.

J Trauma Acute Care Surg 2014 Jul;77(1):166-9

From the Department of Surgery, University of Texas Health Science Center, San Antonio, Texas.

Background: Head injury is the most common cause of neurologic disability and mortality in children. Previous studies have demonstrated that depressed skull fractures (SFs) represent approximately one quarter of all SFs in children and approximately 10% percent of hospital admissions after head injury. We hypothesized that nondepressed SFs (NDSFs) in children are not associated with adverse neurologic outcomes.

Methods: Medical records were reviewed for all children 5 years or younger with SFs who presented to our Level I trauma center during a 4-year period. Data collected included patient demographics, Glasgow Coma Scale (GCS) score at admission, level of consciousness at the time of injury, type of SF (depressed SF vs. NDSF), magnitude of the SF depression, evidence of neurologic deficit, and the requirement for neurosurgical intervention.

Results: We evaluated 1,546 injured young children during the study period. From this cohort, 563 had isolated head injury, and 223 of them had SF. Of the SF group, 163 (73%) had NDSFs, of whom 128 (78%) presented with a GCS score of 15. None of the NDSF patients with a GCS score of 15 required neurosurgical intervention or developed any neurologic deficit. Of the remaining 35 patients with NDSF and GCS score less than 15, 7 (20%) had a temporary neurologic deficit that resolved before discharge, 4 (11%) developed a persistent neurologic deficit, and 2 died (6%).

Conclusion: Children 5 years or younger with NDSFs and a normal neurologic examination result at admission do not develop neurologic deterioration.

Level Of Evidence: Epidemiological study, level III.
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http://dx.doi.org/10.1097/TA.0000000000000256DOI Listing
July 2014
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