Systemic arteriovenous fistulae for end-stage cyanosis after cavopulmonary connection: a useful bridge to transplantation

Asking Bubbles for Direction: Assessment of a Classic Glenn Shunt Using Agitated Saline Contrast Echocardiography

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Glenn shunt is a common palliative surgery for congenital heart disease.

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PAVMs are a frequent complication.

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A saline contrast study can show bubbles first appearing in the left atrium.

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Treatment options include coil embolization and surgery.

Indications for and results of axillary arterio-venous fistula in patients with a functionally single ventricle after cavopulmonary anastomosis†

OBJECTIVES

This study aimed to investigate the indications for and the results of axillary arterio-venous fistula in patients with a functionally single ventricle at mid-term follow-up after bidirectional cavopulmonary connection.

METHODS

From 2012 to 2017, 20 patients aged 21.1 ± 8.7 years (median 20.5) underwent axillary arterio-venous fistula after bidirectional cavopulmonary connection in our institution. The interval between bidirectional cavopulmonary connection and axillary arterio-venous fistula was 13.9 ± 7.2 years. The clinical and haemodynamic parameters of the patients were assessed before and after surgery.

RESULTS

There was no in-hospital mortality. Paraesthesia of the arm persisted for 1-7 days. The mean arterial oxygen saturation increased from 72.4 ± 7.1% pre-surgery to 81.6 ± 5.5% (P < 0.001) after surgery, and was 83.8 ± 6.5% at discharge (P = 0.002 Wilcoxon matched pairs test). The haemoglobin, haematocrit, McGoon index and ejection fraction values did not change significantly. The speed and minute volume of the blood flow in the superior vena cava increased from from 21.1 ± 8.3 cm/s to 28.8 ± 14.9 cm/s (P < 0.001) and from 10.6 ± 3.7 ml/s to 12.5 ± 2.9 ml/s (P < 0.001), respectively. At the mid-term follow-up (1-5 years), 2 patients died from concomitant pathology. Stable improvement in the state and tolerance of physical activity was noted: before surgery, 17 patients were classified as New York Heart Association functional capacity (FC) III and 3 patients as FC IV; after surgery, 9 patients were FC II and 3 patients were FC III. One patient underwent a Fontan operation within 3 years.

CONCLUSIONS

Axillary arterio-venous fistula can be used as the stage of surgical treatment and a bridge to Fontan and/or heart transplantation for this category of patients.

Pulmonary arteriovenous malformations in children after the Kawashima procedure: Risk factors and midterm outcome

Background:

Pulmonary arteriovenous malformations (PAVMs) are the major cause of progressive cyanosis in patients palliated with bidirectional cavopulmonary connection (BCPC). The aim of our study is to analyze the occurrence of PAVMs in patients after Kawashima procedure, to study the effect of total cavopulmonary connection (TCPC) on PAVMs, to evaluate the effect of axillary arteriovenous fistula (AAVF) creation on PAVMs, and to study the risk factors for PAVMs.

Methods:

In this retrospective cohort study, all patients with left isomerism and azygous continuation of an interrupted inferior vena cava who underwent Kawashima procedure from July 2001 to December 2017 were included.

Results:

Twenty.six patients after Kawashima procedure were included in our study. PAVMs were diagnosed in 12 patients (46%). Five of these 12 patients underwent TCPC with complete resolution of hypoxemia. Three patients underwent AAVF creation, 2 had complete resolution, while 1 had partial resolution of hypoxemia. Fourteen patients (54%) did not develop PAVMs. Nakata index below 267 mm²/m²and McGoon ratio below 1.9 predicted the development of PAVMs with high sensitivity and specificity.

Conclusions:

PAVMs represent a serious complication in patients who undergo Kawashima procedure. Small size of pulmonary arteries is an important risk factor for the development of PAVMs. Resolution of hypoxemia after TCPC completion supports the hepatic factor hypothesis. Early TCPC completion in these patients may help to avoid the development of PAVMs by restoring the hepatic factor. Resolution of hypoxemia after AAVF creation may support the lack of pulsatile flow hypothesis.

Superior Cavopulmonary Connection: Its Physiology, Limitations, and Anesthetic Implications

The superior cavopulmonary connection (SCPC) or "bidirectional Glenn" is an integral, intermediate stage in palliation of single ventricle patients to the Fontan procedure. The procedure, normally performed at 3 to 6 months of life, increases effective pulmonary blood flow and reduces the ventricular volume load in patients with single ventricle (parallel circulation) physiology. While the SCPC, with or without additional sources of pulmonary blood flow, cannot be considered a long-term palliation strategy, there are a subset of patients who require SCPC palliation for a longer interval than the typical patient. In this article, we will review the physiology of SCPC, the consequences of prolonged SCPC palliation, and modes of failure. We will also discuss strategies to augment pulmonary blood flow in the presence of an SCPC. The anesthetic considerations in SCPC patients will also be discussed, as these patients may present for noncardiac surgery from infancy to adulthood.

Hepatic Vein Blood Increases Lung Microvascular Angiogenesis and Endothelial Cell Survival-Toward an Understanding of Univentricular Circulation

To improve our understanding of pulmonary arteriovenous malformations in univentricular congenital heart disease, our objective was to identify the effects of hepatic vein and superior vena cava constituents on lung microvascular endothelial cells independent of blood flow. Paired blood samples were collected from the hepatic vein and superior vena cava in children 0-10 years old undergoing cardiac catheterization. Isolated serum was subsequently used for in vitro endothelial cell assays. Angiogenic activity was assessed using tube formation and scratch migration. Endothelial cell survival was assessed using proliferation (BrdU incorporation, cell cycle analysis) and apoptosis (caspase 3/7 activity, Annexin-V labeling). Data were analyzed using Wilcoxon signed-rank test and repeated measures analysis. Upon incubating lung microvascular endothelial cells with 10% patient serum, hepatic vein serum increases angiogenic activity (tube formation, P = 0.04, n = 24; migration, P< 0.001, n = 18), increases proliferation (BrdU, P < 0.001, n = 32; S-phase, P = 0.04, n = 13), and decreases apoptosis (caspase 3/7, P < 0.001, n = 32; Annexin-V, P = 0.04, n = 12) compared to superior vena cava serum. Hepatic vein serum regulates lung microvascular endothelial cells by increasing angiogenesis and survival in vitro. Loss of hepatic vein serum signaling in the lung microvasculature may promote maladaptive lung microvascular remodeling and pulmonary arteriovenous malformations.

Where are we after 50 years of the Fontan operation?

First introduced in 1971, the Fontan procedure is the final common destination for all patients with a functional single ventricle. The procedure itself has evolved tremendously over the last five decades. This review traces this journey and presents the importance, outcomes and future outlook of the procedure in the current era.

Arteriovenous fistula creation for hypoxia after single ventricle palliation: A single-institution experience and literature review

BACKGROUND

Hypoxia is a common and sometimes severe morbidity of single ventricle congenital heart disease (CHD). Creation of an arteriovenous fistula (AVF) is occasionally performed for patients after superior or total cavopulmonary connection (SCPC or TCPC) in an attempt to improve oxygen saturations. Despite previous reports, AVF creation is a rare palliation with inadequately defined benefits and risks. We sought to determine changes in peripheral oxygen saturation (SpO₂ ) and risk of adverse event after AVF creation in children with single ventricle CHD at our institution.

METHODS

We conducted a retrospective chart review of patients with a history of single ventricle palliation and history of surgical AVF creation who were seen at our tertiary care center from 1996 to 2017.

RESULTS

A total of seven patients were included in our study. SpO₂ for the overall cohort did not significantly increase after AVF creation (pre-AVF 79.1 ± 6.9%, post-AVF 82.7 ± 6.0% [P = .23]). SpO₂ trended up for large shunts (>5 mm) (pre-AVF 75.0 ± 7.6%, post-AVF 84.0 ± 5.3% [P = .25]). SpO₂ did not improve for small shunts (≤5 mm) (pre-AVF 82.3 ± 6.5%, post-AVF 81.0 ± 8.5% [P = .50]). The 12-month overall and transplant-free survival were 85.7% and 71.4%, respectively. Freedom from AVF-related complication (cephalic edema, thrombotic occlusion) was 51.4% at 12 months.

CONCLUSION

Palliative AVF creation for patients with single ventricle CHD and hypoxia does not universally improve SpO₂ and is prone to early complications. Despite a lack of durable benefit and known risks, AVF creation remains a reasonable palliation for a subset of patients after SCPC who are not candidates for TCPC, or potentially as a bridge to heart transplantation.

Development of a Pulmonary Arteriovenous Fistula after a Modified Glenn Shunt in Tetralogy of Fallot and Its Resolution after Shunt Takedown in a 57-Year-Old Patient

Pulmonary arteriovenous fistula (PAVF) is a complication of the Glenn shunt. A 57-year-old tetralogy of Fallot (TOF) patient, who had undergone a Glenn shunt and TOF total correction, complained of dyspnea and cyanosis. PAVFs were present in the right lung, and right lung perfusion was nearly absent. After coil embolization, takedown of the Glenn shunt, and reconstruction of the right pulmonary artery, the patient’s symptoms were relieved. Extrapulmonary radioisotope uptake caused by the PAVFs shown in lung perfusion scans decreased, and right lung perfusion increased gradually. Although the development and resolution of PAVFs after a Glenn shunt have been reported in the pediatric population, this may be the first report on this change in old age.

Management of the failing Fontan

With and increasing number of early survivors after the palliation of the single ventricle physiology there is a burgeoning Fontan population worldwide that will pose unique challenges because of the inevitable sequelae related to the absence of the alleged "needless" sub-pulmonic ventricle. The increasing number and older-age single-ventricle patients highlights the results of successful contemporary surgical palliation in children, leading to the development of an adult single-ventricle population with unpredictable socio-economic and health service impacts. The wide variability in clinical status of patients with Fontan circulation reflects not only the broadened spectrum of morphological substrates involved, but also the evolving surgical techniques during the last four decades. This has come in the wake of a gradual understanding of an incredibly tricky physiology. The magnitude of the disease, the physio-pathological mechanisms, and the therapeutic options to optimize the "failing Fontan" status and to delay the irreversible deterioration of "Fontan failure" condition are discussed in this review.

Outcome Following Augmentation of Superior Cavopulmonary Blood Flow With an Arteriovenous Fistula

Background:

Axillary or brachial arteriovenous fistulae are occasionally created to improve systemic oxygen saturation in patients with functionally univentricular circulation after superior cavopulmonary anastomosis. Different techniques of fistula construction may account for the conflicting results. We sought to determine the impact of axillary arteriovenous fistula on systemic oxygen saturation and survival before subsequent palliation or heart transplantation.

Methods:

Medical records of patients who underwent a side-to-side anastomosis between an adjacent axillary artery and vein for cyanosis after superior cavopulmonary anastomosis between 1991 and 2010 were reviewed.

Results:

The median age (n = 23) at the time of fistula creation was 54 months (4-278 months). There was no operative mortality. The median duration of fistula patency was 48 months (1-174 months). Oxygen saturation improved from 71% ± 10% preoperatively to 84% ± 4% early ( P < .05) and 81% ± 4% long term after the arteriovenous fistula ( P < .05). Twelve patients underwent additional surgery (total cavopulmonary anastomosis 6, partial biventricular repair 2, and heart transplantation 4) after an interval of 10 to 141 months. Six patients are alive with a patent fistula without subsequent interventions after an interval of 48 to 174 months. Two patients with spontaneous closure or device closure of the fistula are alive after an interval of 76 to 80 months without subsequent interventions. Three deaths occurred with a patent fistula without subsequent interventions after an interval of 1 to 84 months.

Conclusions:

Systemic oxygen saturation improved with creation of an axillary arteriovenous fistula after superior cavopulmonary anastomosis. The fistula extended the duration of this stage of palliation without precluding the option for additional palliation or heart transplantation.

Pulmonary arteriovenous malformations after the superior cavopulmonary shunt: mechanisms and clinical implications

Children with functional single ventricle heart disease are commonly palliated down a staged clinical pathway toward a Fontan completion procedure (total cavopulmonary connection). The Fontan physiology is fraught with long-term complications associated with lower body systemic venous hypertension, eventually resulting in significant morbidity and mortality. The bidirectional Glenn shunt or superior cavopulmonary connection (SCPC) is commonly the transitional stage in single ventricle surgical management and provides excellent palliation. Some studies have demonstrated lower morbidity and mortality with the SCPC when compared with the Fontan. Unfortunately the durability of the SCPC is significantly limited by the development of pulmonary arteriovenous malformations (PAVMs) which have been commonly attributed to the absence of hepatic venous blood flow and the lack of pulsatile flow to the affected lungs. Abnormal angiogenesis has been suggested as a final common pathway to PAVM development. Understanding these fundamental mechanisms through the investigation of angiogenic pathways associated with the pathogenesis of PAVMs would help to develop medical therapies that could prevent or reverse this complication following SCPC. Such therapies could improve the longevity of the SCPC, potentially eliminate or significantly postpone the Fontan completion with its associated complications, and improve long-term survival in children with single ventricle disease.