MR imaging of aortic coarctation

Diagnosis of covert coarctation of the aorta in adolescents

Objectives

By reviewing the diagnostic process for adolescents with coarctation of the aorta (CoA) in our institution, we analyzed the reasons for delayed diagnosis of CoA. We also proposed a diagnostic protocol to improve the detection rate of CoA.

Methods

In this retrospective study, we included 48 patients aged 12-18 years who were diagnosed with CoA in our hospital from January 2000 to November 2022. Clinical data from involved cases in local hospitals and our institution were collected.

Results

All patients had blood pressure (BP) measurements in upper and lower extremities in our institution. They all had hypertension, 29 (60.4%) of whom had known histories of the same. BP in the upper limbs of 47 (97.9%) patients was ≥20 mmHg higher than that in the lower limbs, and BP in the upper limb of 1 (2.1%) patient was greater than 0 and less than 20 mmHg than that in the lower limb. Echocardiography (ECHO) was performed in all patients, computed tomography (CT) or magnetic resonance imaging (MRI) was performed in 44 patients (91.7%). There were 38 (79.2%) patients who visited local hospitals. Among them, a total of 20 (52.6%) patients had their right upper extremity BP measured, 18 (47.4%) only had their left upper extremity BP measured, and 16 (42.1%) had their lower extremity BP measured. ECHO was performed in 27 (56.2%) patients and CT/MRI was performed in 18 (37.5%) patients. The detection rate for CT/MRI was 100%, and those of ECHO were 72.9% and 18.5% at our institution and a local hospital, respectively. Forty-eight (100%) and 23 (60.5%) patients were detected in our institution and local hospitals (P < 0.0001).

Conclusion

We recommend measuring BP in the bilateral upper extremities. Measurement of BP in the lower extremities is recommended if hypertension is diagnosed. MRI/CT is recommended when BP in the upper extremity is greater than that in the lower extremity.

Cardiac MRI and 3D contrast-enhanced MR angiography in pediatric and young adult patients with Turner syndrome

BACKGROUND/AIM

This study aimed to describe the spectrum and frequency of cardiovascular abnormalities in pediatric and young adult patients with Turner syndrome (TS) using cardiac MRI and MR angiography.

MATERIALS AND METHODS

This prospective study consisted of 47 female patients of pediatric age and young adults with a karyotypically confirmed diagnosis of TS. All patients underwent cardiac MRI and contrast-enhanced MR angiography. A second examination after 9-26 months was performed for 28 of these patients.

RESULTS

Elongation of the transverse aortic arch (ETA) was the most frequent abnormality with a rate of 37%. The rate of partial anomalous pulmonary venous connection (PAPVC) was 21.7%, bicuspid aortic valve (BAV) was 19.6%, coarctation was 6.5%, ascending aorta dilatation was 28.3%, and descending aorta dilatation was 15.2%. The diameters of the aorta and the rate of aortic dilatation per unit of time was greater in the patients with BAV (P < 0.05). ETA was less observed in the patients who were receiving growth hormone therapy (P < 0.05).

CONCLUSION

The most common cardiovascular abnormalities in TS patients are aortic arch anomalies such as ETA and coarctation, aortic dilatation, PAPVCs, and BAV. The presence of BAV is an important risk factor for the aortic dilatation.

Ultrasound imaging velocimetry with interleaved images for improved pulsatile arterial flow measurements: a new correction method, experimental and in vivo validation

Blood velocity measurements are important in physiological science and clinical diagnosis. Doppler ultrasound is the most commonly used method but can only measure one velocity component. Ultrasound imaging velocimetry (UIV) is a promising technique capable of measuring two velocity components; however, there is a limit on the maximum velocity that can be measured with conventional hardware which results from the way images are acquired by sweeping the ultrasound beam across the field of view. Interleaved UIV is an extension of UIV in which two image frames are acquired concurrently, allowing the effective interframe separation time to be reduced and therefore increasing the maximum velocity that can be measured. The sweeping of the ultrasound beam across the image results in a systematic error which must be corrected: in this work, we derived and implemented a new velocity correction method which accounts for acceleration of the scatterers. We then, for the first time, assessed the performance of interleaved UIV for measuring pulsatile arterial velocities by measuring flows in phantoms and in vivo and comparing the results with spectral Doppler ultrasound and transit-time flow probe data. The velocity and flow rate in the phantom agreed within 5-10% of peak velocity, and 2-9% of peak flow, respectively, and in vivo the velocity difference was 9% of peak velocity. The maximum velocity measured was 1.8 m s^-1, the highest velocity reported with UIV. This will allow flows in diseased arteries to be investigated and so has the potential to increase diagnostic accuracy and enable new vascular research.

Pediatric Chest MR Imaging: Sedation, Techniques, and Extracardiac Vessels

Thoracic MR imaging in the pediatric population provides unique challenges requiring tailored protocols and a practical approach to pediatric issues, such as patient motion and sedation. Concern regarding the use of ionizing radiation in the pediatric population has continued to advance the use of MR imaging despite these challenges. This article provides a practical approach to thoracic vascular MR imaging with special attention paid to pediatric-specific issues such as sedation. Thoracic vascular anatomy and pathology are discussed with an emphasis on protocols that can facilitate accurate diagnosis.

Fluid dynamics of coarctation of the aorta and effect of bicuspid aortic valve

Up to 80% of patients with coarctation of the aorta (COA) have a bicuspid aortic valve (BAV). Patients with COA and BAV have elevated risks of aortic complications despite successful surgical repair. The development of such complications involves the interplay between the mechanical forces applied on the artery and the biological processes occurring at the cellular level. The focus of this study is on hemodynamic modifications induced in the aorta in the presence of a COA and a BAV. For this purpose, numerical investigations and magnetic resonance imaging measurements were conducted with different configurations: (1) normal: normal aorta and normal aortic valve; (2) isolated COA: aorta with COA (75% reduction by area) and normal aortic valve; (3) complex COA: aorta with the same severity of COA (75% reduction by area) and BAV. The results show that the coexistence of COA and BAV significantly alters blood flow in the aorta with a significant increase in the maximal velocity, secondary flow, pressure loss, time-averaged wall shear stress and oscillatory shear index downstream of the COA. These findings can contribute to a better understanding of why patients with complex COA have adverse outcome even following a successful surgery.

Ruptured spinal artery aneurysm associated with coarctation of the aorta

BACKGROUND

Spinal artery aneurysms associated with aortic coarctation are exceptionally rare, with only eight cases reported in the literature that we are aware of, and treatment of the aneurysm described only in one of them. Aortic coarctation often results in an aberrant collateral circulation with hyperdynamic flow and potential spinal artery aneurysm formation, growth, and rupture. Microsurgical, interventional, and medical management of these lesions can be challenging and has rarely been reported. Complication avoidance requires thorough knowledge of the clinical presentation of the disease, the hemodynamic factors involved, and the therapeutic tools available.

CASE DESCRIPTION

A 59-year-old woman with a previously undiagnosed isthmic coarctation of the aorta presented with subarachnoid hemorrhage. A 7-mm wide-necked, saccular spinal artery aneurysm was identified as the source of the hemorrhage and was subsequently successfully coiled through a transbrachial access route. After rehabilitation, the patient returned to her asymptomatic neurologic baseline, and underwent successful surgical repair of the aortic coarctation with placement of an interposition graft.

CONCLUSIONS

Spinal artery aneurysms induced by aortic coarctation are rare and complex entities. They pose unique surgical and medical challenges. Securing the aneurysm should be prioritized specifically in cases of subarachnoid hemorrhage. Blood pressure should be closely monitored and balanced to reduce the risk of rehemorrhage and at the same time allow for sufficient end-organ perfusion.

Vascular and autonomic function in preschool-aged children with congenital heart disease

OBJECTIVE

To compare indices of vascular health and heart rate variability in preschool-aged children with repaired congenital heart disease (CHD) including tetralogy of Fallot (n = 6) and coarctation of the aorta (n = 6).

DESIGN

  A cross-sectional study design was used. All measures were noninvasive and collected over a single testing session under the supervision of a parent/guardian.

SETTING

  Data collection took place in a quiet, temperature-controlled room (23°± 1°C) with the participant in a supine position.

PATIENTS

  Twelve (six females, six males) preschool-aged children with repaired CHD (CHD: 4 ± 1 years) and 12 age- and gender-matched healthy controls (CON: 5 ± 1 years) participated in the study.

OUTCOME MEASURES

  Supine, resting measures of heart rate variability (time, frequency, and nonlinear domains), whole-body pulse wave velocity (ventricular depolarization to dorsalis pedis artery), brachial blood pressures, and carotid artery distensibility, lumen diameter, intima-media thickness, and wall/lumen ratio were collected in both groups.

RESULTS

  The groups were similar in age, height, and weight; however, CON had significantly higher body mass index values (CON: 16.9 ± 2.2, CHD: 15.1 ± 1.0, P < .05) and body mass index percentiles (CON: 69 ± 27%tile, CHD: 36 ± 24%tile, P < .01) compared to CHD. No group differences were found for resting brachial blood pressures, whole-body pulse wave velocity, heart rate variability, and carotid artery distensibility, lumen diameter, and intima-media thickness (P > .05). Carotid artery pulse pressures (CHD: 38 ± 6 mm Hg, CON: 31 ± 6 mm Hg, P < .05) and wall/lumen ratios (CHD: 0.091 ± 0.007, CON: 0.085 ± 0.006, P < .01) were significantly higher in the CHD group.

CONCLUSIONS

  These results may indicate that preschool-aged children with repaired CHD display early signs of vascular remodeling, but not autonomic or vascular dysfunction. The effects of larger wall/lumen ratios on cardiovascular disease risk require further investigation.

Mathematical, numerical and experimental study in the human aorta with coexisting models of bicuspid aortic stenosis and coarctation of the aorta

Coarctation of the aorta is an obstruction of the aorta and is usually associated with other concomitant cardiovascular abnormalities especially with bicuspid aortic valve stenosis. The objectives of this study are, (1) to investigate the effects of coarctation on the hemodynamics in the aorta to gain a better understanding of the cause of certain post-surgical coarctation problems, (2) to develop and introduce a new lumped parameter model, mainly based on non-invasive data, allowing the description of the interaction between left ventricle, coarctation of the aorta, aortic valve stenosis, and the arterial system.

Severe diffuse hypoplasia of the aorta associated with multiple vascular abnormalities

Hypoplasia of the thoracic and abdominal aorta is an extremely rare vascular pathology. The most common clinical manifestation is severe uncontrolled hypertension in adolescents and young adults. Medical treatment alone can decrease blood pressure, but often very high doses of antihypertensive drugs are needed. When hypertension is refractory to the antihypertensive medications, surgical revascularization is considered as the treatment of choice. We report the case of a severe and diffuse hypoplasia of the aorta, beginning with the aortic isthmus, to the aortic bifurcation, associated with an aberrant celiac trunk and superior mesenteric artery, and with other multiple vascular abnormalities. Unlikely, the only manifestation of this extensive vascular malformation was medicamentously controllable hypertension. To our knowledge, this severe vascular anomaly, with such a minimal clinical manifestation, has not been previously described in the English literature.