Left subclavian flap aortoplasty for coarctation of the aorta: effects on forearm vascular function and growth

The Society of Thoracic Surgeons Clinical Practice Guidelines on the Management of Neonates and Infants With Coarctation

BACKGROUND

Although coarctation of the aorta without concomitant intracardiac pathology is relatively common, there is lack of guidance regarding aspects of its management in neonates and infants.

METHODS

A panel of experienced congenital cardiac surgeons, cardiologists, and intensivists was created, and key questions related to the management of isolated coarctation in neonates and infants were formed using the PICO (Patients/Population, Intervention, Comparison/Control, Outcome) Framework. A literature search was then performed for each question. Practice guidelines were developed with classification of recommendation and level of evidence using a modified Delphi method.

RESULTS

For neonates and infants with isolated coarctation, surgery is indicated in the absence of obvious surgical contraindications. For patients with risk factors for surgery, medical management before intervention is reasonable. For those stable off prostaglandin E1, the threshold for intervention remains unclear. Thoracotomy is indicated when arch hypoplasia is not present. Sternotomy is preferable when arch hypoplasia is present that cannot be adequately addressed through a thoracotomy. Sternotomy may also be considered in the presence of a bovine aortic arch. Antegrade cerebral perfusion may be reasonable when the repair is performed through a sternotomy. Extended end-to-end, arch advancement, and patch augmentation are all reasonable techniques.

CONCLUSIONS

Surgery remains the standard of care for the management of isolated coarctation in neonates and infants. Depending on degree and location, arch hypoplasia may require a sternotomy approach as opposed to a thoracotomy approach. Significant opportunities remain to better delineate management in these patients.

Vertebrobasilar insufficiency after subclavian flap aortoplasty for aortic coarctation

The mainstay of treatment of pediatric aortic coarctation is open surgery. One option for repair includes subclavian flap aortoplasty, first described by Waldhausen and Nahrwold in 1966. Within this technique, several modifications have been made over the years as long-term follow-up data became available. Early outcomes revealed little concern for left upper extremity limb ischemia or subclavian steal syndrome. These complications are rare but can have a significantly delayed presentation years after coarctation repair. We present a case of subclavian steal syndrome with lifestyle-limiting vertebrobasilar symptoms experienced by a patient 36 years after subclavian flap aortoplasty for aortic coarctation.

Post-operative musculoskeletal outcomes in patients with coarctation of the aorta following different surgical approaches

BACKGROUND

The aim of this study was to examine range of motion and muscle function in the upper extremity and spine in patients with coarctation of the aorta (CoA) comparing different surgical approaches.

METHODS

From October 2017 to February 2019, 150 patients were assessed for inclusion. A total of 99 patients (n = 75 CoA, n = 24 control), were included and assessed regarding muscle function, arm length and circumference, and spinal and thoracic mobility.

RESULTS

There were significant differences between the right and left arm in patients with CoA, operated with the subclavian flap technique compared to controls in regards to shoulder flexion (p < 0.001), elbow flexion (p = 0.001), shoulder abduction (p = 0.02), handgrip strength (p = 0.01), length of upper arm (p < 0.001), lower arm (p < 0.001), and of whole arm (p < 0.001), circumference regarding upper arm (p = 0.001), lower arm (p < 0.001), and wrist (p < 0.001). Structural scoliosis was more frequent in patients who had undergone thoracotomy (25.4%) than patients who had not undergone a thoracotomy (5.9%, p = 0.04), and were often located in the thoracic part of the spine.

CONCLUSION

Patients with CoA operated on using the subclavian flap technique have impaired muscle function as well as reduced arm length and circumference. An increased rate of structural scoliosis was found in patients who underwent thoracotomy, in comparison with patients who had not undergone a thoracotomy. Further research is needed to determine whether muscle function impaired by surgical procedures can be improved with exercise.

Left arm structure and function late after subclavian flap repair of aortic coarctation in childhood

OBJECTIVES

Concerns exist over the long-term consequences of subclavian artery ligation in subclavian flap repair for coarctation of the aorta. We sought to analyse upper limb structural and functional performance in adults who have had surgery in childhood for coarctation of the aorta, using either subclavian flap repair or end to end aortic anastomosis.

METHODS

Two-group observational design using anatomical and upper limb functional performance measures. Purposive sampling from our specialist adult congenital heart disease database of patients who received subclavian flap repair or end to end anastomosis for coarctation of the aorta as children. Upper limb measurements were completed using MRI and blood flow velocity with ultrasound imaging. Bilateral standardised upper limb functional testing of assessment of strength, dexterity and a standardised self-report of upper limb disability was completed.

RESULTS

Eighteen right-handed patients, 9 with subclavian repair, (38 ± 12 years, 78% males) were studied. Age at repair was 4.7 ± 5.9 years; mean time from initial repair 32 ± 9 years. The subclavian group had a larger difference between right and left when compared the end to end anastomosis group in: lower arm muscle mass (94.5 ± 42.3 mls versus 37.8 ± 94.5 mls, p = 0.008), lower arm maximal cross-sectional area, (5.9 ± 2.8 cm2 versus 2.9 ± 2.6 cm2, p = 0.038) and grip strength (14.7 ± 8.3 lbs versus 5.9 ± 5.3 lbs, p = 0.016) There were no significant functional differences between groups.

CONCLUSIONS

In adults with repaired coarctation of the aorta, those with subclavian flap repair had a greater right to left arm muscle mass and grip strength differential when compared to those with end to end anastomosis repair.

Bovine arch anatomy influences recoarctation rates in the era of the extended end-to-end anastomosis

OBJECTIVES

Arch branching has never been shown to influence recoarctation after extended end-to-end anastomosis via thoracotomy, yet in each study bovine arch identification is grossly underreported. This study aims to (1) assess chart review reliability in bovine arch identification; (2) determine recoarctation risk with a bovine arch; and (3) explore an anatomic explanation for recurrent arch obstruction based on arch anatomy.

PATIENTS

A total of 49 consecutive patients underwent thoracotomy with extended end-to-end aortic coarctation repair at a single institution (2007-2012).

METHODS

Echocardiograms from these patients were reviewed for arch anatomy and compared with the echocardiographic reports. Recurrent arch obstruction was defined as an echocardiographic gradient across the repair of 20 mm Hg or greater. For cases with angiographic images (n = 17), a scaled clamping distance between the left subclavian artery and the maximal proximal clamp location on orthogonal projections was then calculated across arch anatomies.

RESULTS

Chart review identified 6.1% (3/49) of patients with a bovine arch compared with 28.6% (14/49) on targeted image review. A total of 28.6% (4/14) of patients with a bovine arch had a follow-up gradient of 20 mm Hg or greater. Only 5.7% (2/35) of patients with normal arch branching had a follow-up gradient of 20 mm Hg or greater. The mean clamping index was significantly diminished in patients with bovine arch anatomy.

CONCLUSIONS

Arch anatomy often goes undocumented on preoperative imaging, yet children undergoing extended end-to-end repair with bovine arch anatomy are at a significantly increased risk of recoarctation. This may be due to a reduced clampable distance to facilitate repair. These results should be considered in the preoperative assessment, parental counseling, and surgical approach for children with discrete aortic coarctation.

A viable therapeutic option: mechanical circulatory support of the failing Fontan physiology

A blood pump specifically designed to augment flow from the great veins through the lungs would ameliorate the poor physiology of the failing univentricular circulation and result in a paradigm shift in the treatment strategy for Fontan patients. This study is the first to examine mechanical cavopulmonary assistance with a blood pump in the inferior vena cava (IVC) and hepatic blood flow. Five numerical models of mechanical cavopulmonary assistance were investigated using a three-dimensional, reconstructed, patient-specific Fontan circulation from magnetic resonance imaging data. Pressure flow characteristics of the axial blood pump, energy augmentation calculations for the cavopulmonary circulation with and without pump support, and hemolysis estimations were determined. In all of the pump-supported scenarios, a pressure increase of 7-9.5 mm Hg was achieved. The fluid power of the cavopulmonary circulation was also positive over the range of flow rates. No retrograde flow from the IVC into the hepatic circulation was evident during support cases. Vessel suction risk, however, was found for greater operating rotational speeds. Fluid shear stresses and hemolysis predictions remained at acceptable levels with normalized index of hemolysis estimations at 0.0001 g/100 L. The findings of this study support the continued design and development of this blood pump technology for Fontan patients with progressive cardiovascular insufficiency. Validation of these flow and performance predictions will be completed in the next round of experimental testing with blood bag evaluation.

Preclinical models of human peripheral arterial occlusive disease: implications for investigation of therapeutic agents

Peripheral arterial occlusive disease (PAOD) is now recognized as a combination of clinical syndromes that are associated with significant morbidity and mortality. The primary pathophysiology of PAOD is impaired perfusion to the lower extremity. Effective pharmacotherapy designed to increase perfusion in PAOD is lacking, and revascularization options are suboptimal. New and more efficacious therapies that improve blood flow are definitely needed, and thus designing, describing, and validating these new therapies in preclinical PAOD models will be essential. This study describes the various preclinical PAOD models presently in use, correlates the models to human PAOD, and reviews the available end points that can be used to detect a response to therapy.

Resetting of the cardiopulmonary baroreflex 10 years after surgical repair of coarctation of the aorta

OBJECTIVE

To characterise cardiopulmonary baroreflex responses and examine the effects of a 45 minute cycling bout late after successful repair of coarctation of the aorta.

SUBJECTS

10 young adults (mean (SEM) age 18.1 (2.6 years)) operated on for coarctation of the aorta 12.7 (3.5) years earlier, and 10 healthy controls.

DESIGN

Forearm blood flow (venous occlusion plethysmography) and vascular resistance, left ventricular internal diastolic diameter, and central venous pressure estimated from an antecubital vein were measured in the supine position at baseline and during five minute applications of lower body negative pressure (LBNP) at -15 mm Hg (LBNP(-15)) and -40 mm Hg (LBNP(-40)). Venous samples were obtained at baseline and during LBNP(-40) for noradrenaline (norepinephrine), adrenaline (epinephrine), renin activity, and aldosterone. The tests were repeated after 45 minutes of moderate exercise.

RESULTS

Baseline heart rate (78 (9) v 64 (6) beats/min), echocardiographic cardiac output (6.9 (1.1) v 5.0 (0.2) l/min), shortening fraction (41.7 (1.8)% v 33.3 (1.3)%), and forearm blood flow (3.4 (0.4) v 2.3 (0.3) ml/100 g/min) were higher in the coarctation group than in the controls (p < 0.05). Changes in forearm blood flow and forearm vascular resistance from baseline to LBNP(-40) were similar in both groups, but the relation between forearm vascular resistance and estimated central venous pressure or left ventricular internal diastolic diameter was shifted downward in the coarctation group. Plasma adrenaline was increased in the coarctation group (baseline: 3.2 (0.6) v 2.4 (0.3) pmol/l in controls; LBNP(-40): 687 (151) v 332 (42) pmol/l) (p < 0.05). Both groups showed a similar downward displacement of forearm vascular resistance (p < 0.05) after exercise.

CONCLUSIONS

There appears to be resetting of the cardiopulmonary baroreflex to a lower forearm vascular resistance in young adults operated on for coarctation of the aorta, associated with hyperdynamic left ventricular function. Raised circulating adrenaline could contribute to the lower forearm vascular resistance.

Surgical Correction of Vascular Ring Anomalies

Between 1981 and 1997, 25 patients underwent operations for relief of tracheoesophageal compression due to vascular rings. Seventeen patients (68%) had a double aortic arch, 6 (24%) had a right aortic arch with an anomalous left subclavian artery and ligamentum arteriosum, and 2 (8%) had a left aortic arch with an anomalous right subclavian artery arising from a Kommerell's diverticulum. Preoperative symptoms consisted of stridor and dysphagia. Four patients (16%) were ventilator-dependent prior to surgery. After division of the vascular ring, wide dissection of the superior mediastinal structures was performed to prevent any compression of the trachea or esophagus. There were no early deaths. Ventilatory support was necessary for a mean of 48 ± 8 hours. One patient required reintubation for 24 hours due to persistent left lower lobe atelectasis. During late follow-up, 2 patients (8%) had recurrent pneumonia, and there were 2 deaths. Surgical repair of vascular rings provided excellent early and late results. The index of suspicion of these aortic arch anomalies should increase if an infant or young child presents with a history of recurrent stridor, dysphagia, or respiratory distress that is not easily explained.

Coarctation repair: modification of end-to-end anastomosis with subclavian flap angioplasty

BACKGROUND

Subclavian angioplasty and resection and end-to-end anastomosis for coarctation repair carry a substantial risk of recurrence of coarctation. The combined technique using both these methods has shown good results but requires a longer period of continuous cross-clamping of the aorta.

METHODS

A modified technique using intermittent cross-clamping with a period of reperfusion between cross-clamping periods was used. After the end-to-end anastomosis the clamps are released for 10 minutes and reapplied to do the subclavian angioplasty. Between 1991 and 1996 this was done in 26 infants (mean age, 5 weeks; range, 1 day to 6 months; median, 3 weeks). Mean weight was 3.85 kg (range, 1.5 to 8.4 kg). Mean length of follow-up was 23 months. Twenty-two patients (85%) had associated anomalies, excluding patent ductus arteriosus, and 5 patients (19%) had another procedure performed at the same time.

RESULTS

There was no mortality. The mean echocardiographic gradient was 4 mm Hg in the immediate postoperative period and 2.9 mm Hg during follow-up. Residual or recurrent coarctation as detected by significant echocardiography or blood pressure gradient did not develop in any infant.

CONCLUSIONS

This modified technique of anastomosis is an effective way of relieving coarctation with excellent intermediate-term results.

Evaluation of superficial femoral artery compromise and limb growth retardation after transfemoral artery balloon dilatations

BACKGROUND

Abnormalities of arterial pulse and limb growth after retrograde femoral arterial catheterization have been well documented. However, the magnitude of such complications after transfemoral artery balloon dilatation has not been thoroughly investigated. This study sought to evaluate the prevalence of these abnormalities in children who have undergone transfemoral artery balloon dilatation.

METHODS AND RESULTS

Data on 43 consecutive patients (1 day to 15.5 years old at the time of balloon dilatation) seen on follow-up (42 +/- 23 months) (group 1) were compared with those of 35 patients undergoing retrograde femoral arterial catheterization (group 2) and 47 control patients. Interventional ankle/control ankle blood pressure index (AAI), ratio of interventional/control lower limb length (LLI), and leg length difference (LLD) were measured. Ages and weights at study were similar in all three groups, as were the ages and weights at intervention and duration of follow-up in groups 1 and 2. The AAI was lower (P = .023) in group 1 (0.95 +/- 0.13) than in groups 2 (1.0 +/- 0.1) and 3 (1.01 +/- 0.09). The prevalence of subjects with AAI < or = 0.9 was higher (P = .003) in group 1 than in the other two groups. The LLI and LLD were similar (P > .1) in all three groups. AAI and LLD in the balloon group are not significantly associated with age and weight at intervention, duration of follow-up, or size of the balloon or balloon catheter shaft.

CONCLUSIONS

Transfemoral artery balloon dilatation procedures produce superficial femoral artery compromise, but there was no significant limb growth retardation at a 3.5-year mean follow-up, which may be related to development of collateral circulation. Study of a larger number of children at a longer follow-up interval may be necessary to further confirm these observations.

Transsternal repair of coarctation and associated cardiac defects

Over a 13-year period, 20 infants and children underwent transsternal approach for repair of coarctation and associated cardiac defects. Fifteen patients (75%) were operated on in the last 6 years. Thirteen patients (group 1) had intracardiac shunts and 7 (group 2), intracardiac obstruction or valvular insufficiency. Group 1 had a mean age of 0.8 +/- 1.9 years versus 4 +/- 3 years for group 2 (p = 0.05). There were 12 patients (92%), 7 months old or less in group 1. Aortic arch hypoplasia was present in 6 patients in group 1. A large patent ductus arteriosus was present in 5 of these 6 patients versus no patent ductus arteriosus in patients without aortic arch hypoplasia (p = 0.006). The mean pulmonary blood flow to systemic blood flow ratio in group 1 was 3.8 +/- 2 and the mean right ventricular to left ventricular ratio, 0.8 +/- 0.2. The coarctation repair fell mostly into three types: side patch aortoplasty (8), ductal tissue excision and patch aortoplasty of the concavity of the aortic arch (6), and subclavian aortoplasty (4). There was one early death (5%) which was due to sepsis in a newborn. Another newborn who had subclavian aortoplasty needed a left carotid artery--descending aorta bypass conduit early because of aortic arch hypoplasia. All patients were followed to 12 years (mean follow-up, 4.3 +/- 3.5 years). There were no late deaths. Two patients had recurrent coarctation, 1 after an end-to-end repair and the other because of incomplete arch enlargement after a side patch aortoplasty.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of balloon angioplasty in the treatment of aortic coarctation

Since the initial report of coarctation balloon angioplasty in 1982, several groups have used this technique for native coarctations in neonates, infants, and children and for postoperative recoarctations. However, recommendations for use of balloon angioplasty as a treatment procedure of choice are clouded by reports of aneurysm development at the site of coarctation. Here we review our experience as well as that published in the literature, including Valvuloplasty and Angioplasty of Congenital Anomalies Registry data, and present evidence in support of balloon angioplasty as a therapeutic procedure of choice for treating native and recurrent postoperative aortic coarctations. Balloon angioplasty of native aortic coarctations in 20 neonates and infants 1 year old or less reduced peak systolic pressure gradient across the coarctation from 40 +/- 12 mm Hg (mean +/- standard deviation) to 11 +/- 8 mm Hg (p less than 0.001); no patient required immediate surgical intervention. The residual gradient at follow-up (mean follow-up, 12 months) in 16 infants was 18 +/- 16 mm Hg, a significant improvement (p less than 0.01) compared with preangioplasty values. In none of the patients did an aneurysm develop. Recoarctation developed in 5 (31%) of the 16 infants and was successfully treated either by surgical resection (in 2) or by repeat balloon angioplasty (in 3). A comparison of mortality and recurrence rates between the balloon angioplasty and surgical groups was made with the help of data pooled from the literature published since 1980. The initial (7% versus 23%) and late (2% versus 25%) mortality and recoarctation (11% versus 18%) rates were higher (p less than 0.025) after surgical intervention than after balloon therapy. When only reports in which patients were operated on after 1979 were included in this type of analysis, the initial and late mortality rates remained higher (p less than 0.01) after operation than after angioplasty, and the recoarctation rates became similar (p greater than 0.1). Thirty-two children (greater than 1 year old) underwent balloon angioplasty of native coarctation with a resultant reduction in peak systolic pressure gradient from 48 +/- 19 mm Hg to 10 +/- 9 mm Hg (p less than 0.001), which continued to remain low (14 +/- 11 mm Hg; p less than 0.001) at follow-up catheterization in 24 children 13 months (mean) later. There were no immediate or late deaths. A small aneurysm developed in 1 patient (4%) but did not require intervention. Recoarctation developed in 2 patients (8%), and in both, repeat balloon angioplasty was performed with good results.(ABSTRACT TRUNCATED AT 400 WORDS)