Subclavian Artery Research Articles

CASE OF A FEMALE PATIENT WITH ANKYLOSING SPONDYLITIS AND MULTIPLE ANEURYSMS

Aneurysms of the Valsalva sinuses are rare among cardiovascular disorders, with an incidence rate of 0.15%. Most cases are accidentally diagnosed or constated postmortem. Usually, this type of pathology is asymptomatic and might go undetected for a long time before the aneurism erupts. Patients with larger coronary aneurysms often complain of from chest pain, shortness of breath, and arrhythmia. Another extremely rare cardiovascular pathology is the aneurysm of the subclavian artery, which has a reported rate of 0.13%. Smaller subclavian aneurysms have no clinical manifestation, whereas larger ones cause murmur, pulsation phenomenons, neuropathic pain and ischemia of the upper limb due to compression of the brachial plexus and major vessels. Herein, we report a rare case of a very large aneurisms involving all three coronary sinuses and the whole aortic root in combination with a bilateral giant subclavian aneurism. These findings were made during a routine cardiological examination and further hospitalizations of a 54-year-old woman with chest pain and high blood pressure complaints with known ankylosing spondylitis. Despite their rarity, aneurysms of the sinuses of Valsalva and subclavian arteries are of utmost clinical significance due to the life-threatening complications which might arise from their rupture. Furthermore, such aneurysms pose significant technical difficulties during angiographic procedures. Therefore, detailed knowledge of such pathologies is essential for correctly diagnosing and treating such patients.

Study of Morphometric Analysis of Foramen Transversarium and Uncinate Process and Clinical Relevance in Typical Cervical Vertebrae

The foramen transversarium differentiates the cervical vertebrae from the other vertebrae of the spinal column. From the first part of the subclavian artery, the vertebral artery arises and passes through the foramen transversarium. FT protects the vertebral artery. The medial boundary of the luschka joint is a safe sight to protect the vertebral artery. The Uncovertebral Joint, also known as the Luschka Joint, is a joint that was formed by the Uncinate Process between the cervical vertebra bodies. These joints form the medial border of an intervertebral foramen in the cervical area below C-2 and are rarely found on the first thoracic vertebra. The present study was carried out on 100 dry human typical cervical vertebrae of unknown age and sex to determine the morphometric dimensions of FT and Uncinate Process in typical cervical vertebrae. The dimensions were taken by the digital vernier caliper on the superior aspect of the FT and Uncinate Process. The length and width of the FT were more on the left side than on the right side which was statistically insignificant (p-value >0.05). The narrow FTs were also observed in the present study. The mean difference between the Right and Left sides of the Uncinate Process was statistically not significant (p-value>0.05).

A Systematic Comparison of Normal Structure and Function of the Greater Thoracic Vessels.

The greater thoracic vessels are central to a well-functioning circulatory system and are often targeted in congenital heart surgeries, yet the structure and function of these vessels have not been well studied. Here we use consistent methods to quantify and compare microstructural features and biaxial biomechanical properties of the following six greater thoracic vessels in wild-type mice: ascending thoracic aorta, descending thoracic aorta, right subclavian artery, right pulmonary artery, thoracic inferior vena cava, and superior vena cava. Specifically, we determine volume fractions and orientations of the structurally significant wall constituents (i.e., collagen, elastin, and cell nuclei) using multiphoton imaging, and we quantify vasoactive responses and mechanobiologically relevant mechanical quantities (e.g., stress, stiffness) using computer-controlled biaxial mechanical testing. Similarities and differences across systemic, pulmonary, and venous circulations highlight underlying design principles of the vascular system. Results from this study represent another step towards understanding growth and remodeling of greater thoracic vessels in health, disease, and surgical interventions by providing baseline information essential for developing and validating predictive computational models.

Anatomical variations of the brachiocephalic artery and their clinical relevances: A cadaveric study of Ugandan population

The study examined variations in morphology and morphometry of the brachiocephalic artery and their clinical implications in dissected cadavers. Fifty-eight (58) adult cadavers, 57 males and 1 female were dissected to expose the brachiocephalic artery, and the morphological and morphometric variations were recorded.Fifty-one (51) cadavers (88%) had the BCA arising directly from the aortic arch while 7 cadavers (12%) had it originating from the common trunk with the left common carotid artery. The BCA arose on the left anterolateral to the trachea in 57 cadavers (98.3%) and one cadaver (1.7%) had it arising in the midline anterior to the trachea crossed the trachea from left to right terminating posterior to the right sternoclavicular joint where it bifurcated into the right subclavian and right common carotid artery in all cadavers. The mean lengths of the torsos and Brachiocephalic arteries were 45.78±2.93cm and 4.14±0.58cm respectively and the two parameters had statistically significant positive correlation (r=0.33, p<0.05).: A majority of the Ugandan cadaveric population have brachiocephalic arteries with the normal origin, course, and branching patterns. The occurrence of origin variants of BCA from the common trunk and anterior midline to the trachea may be associated with tracheal compression and aortic dilation; hence should be considered as a potential risk factor for thoracic aortic aneurysm and during tracheostomy respectively.

The clinical characteristics of Malaysian patients with Takayasu Arteritis: A retrospective study of 3 decades

Aim of the workTo understand the clinical features, angiographic involvement patterns and outcomes of Takayasu Arteritis (TA) in Malaysian patients. Patients and methodsThis was a retrospective study of 85 TA patients from 20 tertiary rheumatology centers in Malaysia from 1990 until 2020. Demographic information, clinical features, angiographic patterns, treatment and comorbidities were analyzed. ResultsThe female-to-male ratio was 13.1:1. The age at disease onset was 27.47 ± 10.4 years. The duration of delay in diagnosis was 6 ± 27.5 months. 48.2 % were Malay, 12.9 % Chinese, 23.5 % Indian and 14.3 % other ethnicities. Hypertension emerged as the most common comorbidity (52.9 %), followed by dyslipidemia (29.4 %). The most prevalent angiographic pattern was Type V (55.3 %), with left subclavian artery (65.9 %) and left carotid (55.3 %) being the most commonly involved vessels. Glucocorticoids constituted the mainstay of treatment; however, approximately half of the patients required treatment with methotrexate and azathioprine. There were six deaths, primarily attributed to coronary artery disease and infections. Surgical interventions, including angioplasty and bypass surgery, were performed on 11 patients. Out of 44 pregnancies, 79.5 % were successful. ConclusionThis study revealed a pattern of TA disease in Malaysia that aligns with findings from other cohort studies. The most prevalent angiographic type observed was type V, with the subclavian and carotid arteries being the most commonly involved vessels among TA patients in Malaysia. This research contributes to a better understanding of the clinical presentations observed over the past three decades, offering valuable insights for the improved management of TA patients in Malaysia.

Takayasu arteritis - a case report of neurological clinical manifestation in an elderly patient

Takayasu Arteritis is a chronic granulomatous inflammatory arteriopathy that affects the aorta and its main branches, leading to arterial stenosis and sometimes thrombosis, with the left subclavian artery being the most frequently involved. Clinical manifestations are insidious, nonspecific, and variable, depending on the arterial territory affected, without any pathognomonic finding. It is a rare disease, with an annual incidence of 2.6 cases per million people, being more common in Southeast Asia and affecting predominantly women, especially at reproductive age. However, it is believed that this disease is underdiagnosed, especially in the most advanced age groups.

A new imaging classification for safer radial access visceral intervention of the liver and optimal case selection: Apreliminary report.

The aim of this study was to evaluate the use of a new classification for safer transradial access hepatic interventional radiology, based on preoperative evaluation of the location of the left subclavian artery bifurcation in the aortic arch. A total of 38 consecutive patients with hepatocellular carcinoma and 74 sessions of radial access for visceral intervention (R.A.V.I.) were reviewed. We classified the location of the left subclavian artery bifurcation in the aortic arch in three areas using an oblique view computed tomography image matched with the curve of the aortic arches according to a new criteria Three Areas Criteria For R.A.V.I. (named "TAC-F-R"), and measured the required time from initial left radial artery arteriography to celiac artery or superior mesenteric artery arteriography. The median time required for left radial artery arteriography to the celiac artery or superior mesenteric artery arteriography in each of the three areas were: area A, 0:11:10 (h, min, s); area B, 0:14:44; and area C, 0:31:51. There were significant differences between each area after Bonferroni correction (p<0.01; A vs. B, p=0.086; A vs. C, p=0.001; and B vs. C, p=0.045), with areas A and B requiring a significantly shorter time. Finally, no patients showed neurogenic disfunction within 1week after the R.A.V.I. The new classification, "TAC-F-R," for safer transradial access hepatic interventional radiology is effective for avoiding difficult cases, and selects more suitable patients with hepatocellular carcinoma for the R.A.V.I.

Presence of subclinical giant cell arteritis in patients with morning stiffness of duration less than 45 minutes at the time of diagnosis of polymyalgia rheumatica.

In some patients with polymyalgia rheumatica (PMR), giant cell arteritis (GCA) is subclinical as underlying inflammation of large vessels (LV) is present without evidence of related clinical manifestations. Different factors have been proposed as predictive of subclinical GCA in PMR patients. To date, the literature reports scant data about the association between subclinical GCA and long-lasting morning stiffness (MS) in patients at the time of diagnosis of PMR. Given this background, the aim of this study was to assess the association between subclinical GCA and MS < 45 min in patients with newly diagnosed PMR. We performed an observational, retrospective, single-centre cohort study of patients consecutively referred to our public out-of-hospital rheumatologic clinic between January 2015 and December 2020, who could be classified as having PMR according to the 2012 EULAR/ACR criteria. Subclinical GCA was investigated through ultrasound examination of a core set of arteries (temporal, axillary, common carotid, and subclavian arteries), in accordance with the EULAR recommendations for the use of imaging in LV vasculitis. Patients who did not have GCA symptoms but showed halo sign in at least one of these arteries were described as having subclinical GCA. We included a total of 143 patients (35 men and 108 women). Their median age was of 71.5 years. Thirty-five had MS duration < 45 min at the time of PMR diagnosis. Subclinical GCA was found in 23 PMR patients (16.1%); 18 had a cranial and 5 an extracranial GCA. A univariate analysis highlighted that MS < 45 min was associated with a lower prevalence of GCA (OR = 0.11, 95% CI: 0.04-0.29; p < 0.0001). This association was retained in a multivariable analysis that accounted for 6 different potential covariates (OR = 0.06, 95% CI: 0.01-0.26; p < 0.0001. In our study MS < 45 min at the time of PMR diagnosis was associated with a significantly lower risk of subclinical GCA, when patients were screened by ultrasound, of approximately 90%. Identification of a more accurate MS cut-off value could improve the accuracy for subclinical GCA in patients with newly diagnosed PMR.

Surgical treatment for right-side aortic arch concomitant with Kommerell’s diverticulum: techniques selection and follow-up results

BackgroundRight-side aortic arch concomitant with Kommerell’s diverticulum (KD) is a rare and complex ailment, and there is no consensus on the optimal strategy to deal with this congenital anomaly. We retrospectively analyzed and summary of the cases treated in our center with individual treatment methods for different situations.MethodsBetween September 2018 and December 2021, 10 patients experienced surgical therapy at our institution who presented with a Kommerell’s diverticulum arising from an aberrant subclavian artery from the right-side aortic arch. Four main surgical techniques were applied to those patients: 1. total arch replacement with frozen elephant trunk implantation (n = 2); 2. hybrid procedure combining open arch repair and endovascular intervention (n = 1); 3. total endovascular repair using thoracic endovascular aortic repair (TEVAR) with or without left subclavian artery (LSCA) revascularization (n = 6); 4. direct repair underwent endoaneurysmorrhaphy. Clinical characteristics and outcomes were collected.ResultsThe mean age of these 10 patients was 56.5 years (range 29–79 years) and only 1 woman. The pathology includes aortic dissection (n = 6) and aneurysm (n = 4). The mean diverticulum size was 41.4 [24.2–56.8] mm. There were no in-hospital deaths, and the median hospital stay was 22 [15–43] days. During the follow-up period (21.4 months, 1–44 months), one died of an unknown cause and one died of esophageal fistula. Two patients underwent second-stage endovascular intervention for distal lesion. And none of the patients had endoleak during the follow-up period.ConclusionsEach of the procedures we have mentioned here has its advantages and disadvantages; individualized treatment should meet the appropriate indications. A single-branched stent graft is feasible and effective in the treatment of aortic disease combined with Kommerell’s diverticulum.

Coincidence of Asymptomatic Aorto-left Atrial Fistula and Aneurysmatic Aberrant Right Subclavian Artery: The Relevance of Multidetector Computed Tomography Angiography

Coincidence of Asymptomatic Aorto-left Atrial Fistula and Aneurysmatic Aberrant Right Subclavian Artery: The Relevance of Multidetector Computed Tomography Angiography

Modified transmanubrial approach for complicated type 1 cervical rib resection requiring subclavian artery reconstruction.

The transmanubrial musculoskeletal sparing approach (TMA) is commonly used for resecting apical lung tumours with vascular involvement. Non-neoplastic conditions which might require surgical exploration of the thoracic outlet include the 'cervical rib', a clinical condition consisting of an additional rib forming above the first rib and growing from the base of the neck just above the clavicle. Type 1 cervical rib-when a complete cervical rib articulates with the first rib or manubrium of the sternum-is the most challenging scenario where the subclavian artery can be damaged by continuous compression due to the narrow space between clavicle, first rib and supernumerary cervical rib, requiring prosthetic reconstruction of the involved tract. Here, we describe a modified TMA in which the incision in the neck is conducted posteriorly to the sternocleidomastoid muscle, thus allowing safe dissection of the superior and middle trunk of the brachial plexus.

Hemodynamic changes for half cover left subclavian artery ostium during thoracic endovascular aortic repair.

Some clinicians use endografts to cover half the left subclavian artery (LSA) ostium to cure some cases with insufficient proximal landing zone (PLZ) in thoracic endovascular aortic repair (TEVAR) treatment. We used computational fluid dynamics (CFD) to study the hemodynamic changes in the LSA because they may cause acute thrombosis or arteriosclerosis. The digital model of the aortic arch was established and named model A, which only included the supraarch branch of the LSA. By directly covering half of the LSA ostium, which was named as model B. All established models were imported into the Gambit grid division software for grid division and were subsequently imported into the Fluent software for hemodynamic numerical simulation and calculation to analyze the related changes in LSA hemodynamic parameters after stent implantation. Under the same aortic inlet flow, in model B, the local blood flow velocity of the LSA ostium increased and the whole blood flow velocity at the distal end decreased. The average wall shear stress (WSS) of the LSA was significantly decreased. Meanwhile there was an obvious turbulent flow in the LSA lumen, and the related blood flow state was disordered. CFD research confirmed that the implantation of an endograft covering half the LSA ostium can cause obvious hemodynamic changes, which is likely to cause a long-term arteriosclerosis or acute thrombosis of the LSA, finally increasing the risk of stroke. Once this operation is performed in some specific clinical cases for simplicity and economy, it seems that we should actively antiplatelet and follow up regularly.

Analysis of Flow Through Extra-Anatomic Bypasses Between Supra-Aortic Branches Using Particle Image Velocimetry (PIV).

Supra-aortic extra-anatomic debranch (SAD) are prosthetic surgical grafts used to revascularize head and neck arteries that would be blocked during a surgical or hybrid procedure used in treating ascending and arch of the aorta pathologies. However, bypassing the supra-aortic arteries but not occluding their orifice might introduce potential for competitive flow that reduces bypass patency. Competitive flow within the bypasses across the supra-aortic arteries has not previously been identified. This research identified haemodynamics due to prophylactic inclusion of bypasses from the brachiocephalic artery (BCA) to the left common carotid artery (LCCA), and from the LCCA to left subclavian artery (LSA). Four model configurations investigated the risk of competitive flow and the necessity of intentionally blocking the proximal LSA and/or LCCA. Particle image velocimetry (PIV) was used to assess haemodynamics in each model configuration. We found potential for competitive flow in the BCA-LCCA bypass when the LSA was blocked, in the LSA-LCCA bypass, when the LCCA alone or LCCA and LSA were blocked. Flow stagnated at the start of systole within the RCCA-LCCA bypass, along with notable recirculation zones and reciprocating flow occurring throughout systolic flow. Flow also stagnated in the LCCA-LSA bypass when the LCCA was blocked. There was a large recirculation in the LCCA-LSA bypass when both the LCCA and LSA were blocked. The presence of competitive flow in all other configurations indicated that it is necessary to block or ligate the native LCCA and LSA once the debranch is made and the thoracic endovascular aortic repair (TEVAR) completed.

Clinical outcomes and aortic remodeling after Castor single-branched stent-graft implantation for type B aortic dissections involving left subclavian artery.

The left subclavian artery (LSA) can be intentionally covered by a stent graft to acquire adequate landing zones for a proximal entry tear near the LSA during thoracic endovascular aortic repair (TEVAR). The Castor single-branched stent graft is designed to treat type B aortic dissection (TBAD) to retain the LSA during TEVAR. This study investigates clinical outcomes, aortic remodeling, and abdominal aortic perfusion patterns after TEVAR with the novel Castor device. From November 2020 to June 2023, 29 patients with TBAD involving the LSA were treated with the Castor single-branched stent graft. In-hospital clinical outcome and aortic computed tomography angiography (CTA) data were analyzed. CTA was performed preoperatively and at follow-up to observe stent morphology; branch patency; endoleak; change in true lumen (TL), false lumen (FL), and transaortic diameters; and abdominal aortic branch perfusion pattern. The technical success rate was 96.6%. One failure was that the branch section did not completely enter the LSA and the main body migrated distally. No in-hospital mortality, paraplegia, or stroke occurred. During follow-up, one type Ib endoleak, four distal new entry tears, and one recurrent type A dissection arose from a new entry tear at the ascending aorta, no stent migration was observed, and the branch patency rate was 100%. At the thoracic aorta, TL diameters significantly increased, FL diameters markedly decreased, and FL was partially or completely thrombosed in most patients at follow-up. At the abdominal aorta, we observed 33.3% of TL growth and 66.7% of TL stabilization or shrinkage. The initial TL ratio at iliac bifurcation negatively predicted abdominal TL growth after TEVAR with a cutoff of 21.0%. Of the 102 abdominal aortic branches, 94.1% of the branches showed no change in perfusion pattern, 3.9% of the branches had an increased TL perfusion, and 2.0% of the branches had an increased FL contribution. The Castor unibody single-branched stent graft offers an efficient endovascular treatment for TBAD involving the LSA. TEVAR with the Castor device effectively induced thoracic FL thrombosis and thoracic TL enlargement and resulted in abdominal TL growth when the initial TL ratio at iliac bifurcation is less than 21.0%. Abdominal aortic branch perfusion patterns remain relatively stable after TEVAR with the Castor stent graft.

Anomalous Brachial Plexus and their Relationship to the Subclavian Artery in the Supraclavicular Region

The brachial plexus at supraclavicular division level is superior and lateral to the subclavian artery. Thus needle tip positions are already published in literature. However we report the brachial plexus divisions on the medial side of the subclavian artery. This might result in inadequate or failed blocks with landmark guided technique. Moreover with ultrasound needle tip needs to advance medial to artery making it more difficult in expert hands too. Ultrasound imaging of brachial plexus helps in identifying anamolous position of brachial plexus divisions. Keywords- Brachial plexus divisions, Subclavian artery, Ultrasound

Morphology of the aortic arch branching pattern in raccoon dogs (Nyctereutes procyonoides, Gray, 1834).

Aortic arch (AA) branching patterns vary among different mammalian species. Most previous studies have focused on dogs, whereas those on raccoon dogs remain unexplored. The objective of this study was to describe the AA branching pattern in raccoon dogs and compare their morphological features with those of other carnivores. We prepared silicone cast specimens from a total of 36 raccoon dog carcasses via retrograde injection through the abdominal aorta. The brachiocephalic trunk (BCT) branching patterns were classified based on the relationship between the left and right common carotid arteries. The subclavian artery (SB) branching pattern was examined based on the order of the four major branches: the vertebral artery (VT), costocervical trunk (CCT), superficial cervical artery (SC), and internal thoracic artery (IT). In most cases (88.6%), the BCT branched off from the left common carotid artery and terminated in the right common carotid and right subclavian arteries. In the remaining cases (11.4%), the BCT formed a bicarotid trunk. The SB exhibited various branching patterns, with 26 observed types. Based on the branching order of the four major branches, we identified the main branching pattern, in which the VT branched first (98.6%), the CCT branched second (81.9%), the SC branched third (62.5%), and the IT branched fourth (52.8%). The AA branching pattern in raccoon dogs exhibited various branching patterns with both similarities and differences compared to other carnivores.

Iodine contrast volume reduction in preoperative transcatheter aortic valve implantation computed tomography: Comparison with 64- and 256-multidetector row computed tomography

IntroductionThis study aimed to compare the vascular enhancement and radiation dose in preoperative transcatheter aortic valve implantation (TAVI) computed tomography (CT) with a reduced contrast medium (CM) using volume scans in 256-multidetector row CT (MDCT) with a standard CM using 64-MDCT. MethodsThis study included 78 patients with preoperative TAVI CT with either 64- or 256-MDCT. The CM was injected at 1.5 mL/kg in the 64-MDCT group and 1.0 mL/kg in the 256-MDCT group. We compared vascular enhancement of the aortic root and access routes, image quality (IQ) scores, and radiation dose in both groups. ResultsDespite the reduced CM (by 33 %) in the 256-MDCT group, the mean vascular enhancement of the right and left subclavian arteries was significantly higher than that in the 64-MDCT group [284 and 267 Hounsfield units (HU) vs. 376 and 359 HU; p < 0.05]; however, no significant differences in the mean vascular enhancement in the ascending aorta, abdominal aorta at the celiac level, and bilateral common femoral arteries were observed between the two groups (p > 0.05 for all). The median IQ scores at the aortic root were higher in the 256-MDCT group than in the 64-MDCT group (3 vs. 4; p < 0.05), and those at the femoral access routes were comparable (4 vs. 4; p = 0.33). The mean effective dose was significantly reduced by 30 % in the 256-MDCT group (23.6 vs. 16.3 mSv; p < 0.05). ConclusionIn preoperative TAVI CT, volume scans using 256-MDCT provide comparable or better vascular enhancement and IQ with a 30 % reduction in CM and radiation dose than those using 64-MDCT. Implications for practiceVolume scan using 256-MDCT for preoperative TAVI CT may reduce CM and radiation dose in TAVI patients with renal dysfunction.

Congenital continuous retrograde basilar flow suggests type B interrupted aortic arch in a neonate: A case report

Reversed flow in the basilar artery can be acquired or congenital. Acquired reversed flow in the basilar artery can result from acute thrombosis of the basilar artery or retrograde vertebral artery flow. Congenital continuous retrograde basilar artery flow has not been described. We report a 2-day-old male presenting with hypocalcemic seizures which led us to obtain a Duplex echoencephalogram. An echocardiogram was subsequently ordered. In the coronal plane through the anterior fontanelle, retrograde flow was seen in the basilar artery and the right vertebral artery. In the axial plane through the temporal window, the flow was anteroposterior in both posterior communicating arteries. In the posterior cerebral arteries, the flow was retrograde in the P1 segment and anterograde in the P2 and P3 segments. An interrupted aortic arch was suspected. The echocardiogram showed a large perimembranous ventricular septal defect with bidirectional shunting, a hypoplastic and bicuspid aortic valve, an aortic arch interrupted between the left common carotid artery and the left subclavian artery (type B interrupted aortic arch), and a 5 mm patent ductus arteriosus with predominant right to left flow. Because of the patency of the large patent ductus arteriosus, our patient showed no sign of posterior circulation insufficiency. Prostaglandin E1 therapy was initiated immediately. Diagnosis of DiGeorge syndrome was proven. The infant underwent interrupted aortic arch repair and anterograde flow was established in the basilar artery. We conclude that congenital asymptomatic continuous retrograde flow in the basilar artery and left vertebral artery is a medical emergency as it implies the presence of type B interrupted aortic arch with large patent ductus arteriosus in a neonate.

Double aortic arch: a comparison of fetal cardiovascular magnetic resonance, postnatal computed tomography and surgical findings

In double aortic arch (DAA), one of the arches can demonstrate atretic portions postnatally, leading to diagnostic uncertainty due to overlap with isolated right aortic arch (RAA) variants. The main objective of this study is to demonstrate the morphological evolution of different DAA phenotypes from prenatal to postnatal life using three-dimensional (3D) fetal cardiac magnetic resonance (CMR) imaging and postnatal computed tomography (CT)/CMR imaging. Three-dimensional fetal CMR was undertaken in fetuses with suspected DAA over a 6-year period (January 2016-January 2022). All cases with surgical confirmation of DAA were retrospectively studied and morphology on fetal CMR was compared to postnatal CT/CMR and surgical findings. Thirty-four fetuses with surgically confirmed DAA underwent fetal CMR. The RAA was dominant in 32/34 (94%). Postnatal CT/CMR was undertaken at a median age of 3.3months (interquartile range 2.0-3.9) demonstrating DAA with patency of both arches in 10/34 (29%), with 7 showing signs of coarctation of the left aortic arch (LAA). The LAA isthmus was not present on CT/CMR in 22/34 (65%), and the transverse arch between left carotid and left subclavian artery was not present in 2 cases. Fetal CMR provides novel insights into perinatal evolution of DAA. The smaller LAA can develop coarctation or atresia related to postnatal constriction of the arterial duct, making diagnosis of DAA challenging with contrast-enhanced CT/CMR. This highlights the potentially important role for prenatal 3D vascular imaging and might improve the interpretation of postnatal imaging.

Clinical Presentation and Therapy of Tetralogy of Fallot and Double-Outlet Right Ventricle.

Tetralogy of Fallot (TOF) is the most common cyanotic heart defect. TOF consists of the combination of four anomalies (Fig. 35.1): (1) a large malalignment ventricular septal defect, (2) an obstruction of the right ventricular outflow tract (usually infundibular and valvular pulmonary stenosis with a small pulmonary valve annulus and supravalvular stenosis, (3) an aorta that "overrides" the ventricular septal defect, and (4) right ventricular hypertrophy. TOF represents 4-8% of congenital heart defects. Specific variations of TOF include all forms of pulmonary atresia with VSD and absent pulmonary valve syndrome. In addition, the left and right main pulmonary arteries may be stenotic or hypoplastic. In these cases, there may be major aortopulmonary collateral arteries (MAPCAs) which are vessels arising from the aorta or the subclavian arteries that supply segments of the pulmonary arterial tree. Additional variations include an ASD (Pentalogy of Fallot), a right aortic arch, and coronary abnormalities.