Pulmonary expression of the hepatocyte growth factor receptor c-Met shifts from medial to intimal layer after cavopulmonary anastomosis

Outcomes of Patients Undergoing the Kawashima Procedure at an Early Age: A Single Center Experience

BACKGROUND

Previous reports have demonstrated the safety and efficacy of performing early Kawashima procedure (KP). Despite this, more recent studies have shown that the average age at the time of operation remains greater than one year of age. We report our experience with performing KP at an earlier age than previously reported.

METHODS

A retrospective review was completed of patients undergoing KP at a single center (January 2000 to June 2020). Clinical outcomes were examined.

RESULTS

Initial palliation was performed in 11 out of 12 patients. Age and weight at time of KP were 8.25 months (6.4-9.7) and 7.7 kg (6.5-8.6). Intensive care unit stay was 3.16 days (1-12), overall length of stay was 9.5 days (3-22). There was one unplanned reoperation, and no mortality in the cohort. Discharge oxygen saturation was 88% (80%-98%). Seven patients developed pulmonary arteriovenous malformations (PAVMs) with six proceeding to hepatic vein incorporation (HVI). Interval time to development of PAVMs was 42.3 months (16-121). Four of the 12 patients were left with antegrade pulmonary blood flow (PBF) and three (75%) remain without PAVMs. Median follow-up was 10 years (1.5-22) with 11 of 12 (91.67%) survival for the cohort.

CONCLUSIONS

The KP can be done at a younger age than previously reported with adequate early and late results. Most patients will go on to develop PAVMs and require HVI but leaving patients with some antegrade PBF is likely protective but will need further investigation to show definitive benefit.

Is the Hepatic Factor a miRNA that Maintains the Integrity of Pulmonary Microvasculature by Inhibiting the Vascular Endothelial Growth Factor?

Background:

The “hepatic factor,” a molecule or group of molecules present in the hepatic venous blood, essential for the prevention of the development of pulmonary arteriovenous malfor-mations (PAVMs) and right-to-left shunting has been a conceptual enigma in the understanding of many related conditions.

Methods:

Patients with various forms of liver diseases including acute hepatic failure, and others with normal hepatic function like hereditary hemorrhagic telangiectasia (HHT), inflammatory and parasitic disorders, cardiogenic hepatopulmonary syndrome (cHPS) and skin disorders like Dyskeratosis con-genita are all known to cause PAVMs. Over a period of the last two decades our understanding of the pathogenesis of PAVMs has changed, but the mechanisms are still not clearly understood. The pres-ence of PAVMs once considered a contraindication for liver transplantation is now a cure for PAVMs in patients with HPS.

Results:

In this article the molecular mechanisms and the underlying pathogenesis of PAVMs are dis-cussed and the role of microRNA (miRNA) in its pathogenesis is favorably argued. Identifying and preventing or treating the underlying mechanisms will significantly influence the management of a large group of patients who at present cannot be effectively treated with a very poor prognosis. Progressive polycythemia, desaturation, stroke, and infection are serious complications of PAVMs.

Conclusion:

The clinical data and current understanding leads to the possible role of miRNA, which inhibits Vascular Endothelial Growth Factor (VEGF) synthesis as a pathogenic mechanism for the development of PAVMs.

Hepatocyte growth factor protects human mesangial cells against apoptosis induced by lead damage

Lead is a kind of nephrotoxic metal which frequently threats human health. Hepatocyte growth factor (HGF) is a multifunctional growth factor that protects cell apoptosis. In this study, human mesangial cells (HMCs) were treated with a single HGF dose of 20 and 40 μl/ml in order to investigate the effect of HGF on proliferation and apoptosis ability of HMCs induced by lead acetate. In HGF-treated group, HMCs were incubated with HGF (20, 40 μl/ml) half an hour prior to lead inducing. After lead-induced damage 48 h, the proliferation of HMCs was measured by MTT assay, and the apoptosis was assessed by flow cytometry. RT-PCR was used to detect the expression of P53, Bcl-2, Bax, and caspase-3 mRNA. The expression of Bax protein was measured by Western blot analysis. The results showed that HGF inhibits proliferation of HMCs induced lead acetate in a dose-dependent manner (P < 0.05). HGF significantly promoted the proliferation of HMCs, and flow cytometry revealed that HGF can inhibit apoptosis of HMCs. RT-PCR and Western blot showed that P53, Bax, and caspase-3 expression decreased, while Bcl-2 expression increased. HGF may afford a protection to HMCs against lead-induced damage.

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

OBJECTIVE

Intractable cyanosis after partial or complete cavopulmonary connection may rarely be managed by creating a systemic arteriovenous fistula. We investigated the long-term performance of arteriovenous fistulae.

METHODS

All 21 patients who received an arteriovenous fistula at The Hospital for Sick Children since the 1950s were investigated using parametric competing risk techniques. Primary arteriovenous fistula indication was (1) suboptimal pulmonary blood flow (N = 15) or (2) pulmonary shunting via pulmonary arteriovenous malformations (N = 6). Arteriovenous fistula longevity was determined by time to "occlusion" (absence of arteriovenous fistula flow via surgical ligation or spontaneous occlusion).

RESULTS

All 21 patients had previously undergone second-stage palliation (Glenn shunt = 13; bidirectional shunt = 9). Five patients had undergone Fontan completion. Death in the presence of a functioning arteriovenous fistula occurred in 5 patients. Patients with bidirectional shunts had a significantly higher risk of death with a functioning arteriovenous fistula in situ (P = .04). High hemoglobin concentrations were associated with best outcome, and levels less than 170 g/L were associated with a high risk of death despite a functioning arteriovenous fistula (P < .01). Arteriovenous fistula occlusion occurred in 10 patients. Earlier occlusion was associated with previous Fontan completion (P = .02) and pulmonary arteriovenous malformations (P = .03). Surgical ligation during cardiac transplantation was the cause of occlusion in 7 patients. In these 7 patients, the arteriovenous fistula functioned for a median of 4.8 years. After transplantation, survival was 67% + or - 19% at 5 years. Overall survival was 73% + or - 10% 15 years after receiving an arteriovenous fistula (longest survival, 27.3 years).

CONCLUSION

In patients with adequate hematocrit, arteriovenous fistula offers an effective bridge to transplantation when a high-risk Fontan procedure is deferred. Performance is best after unidirectional cavopulmonary connection and worse in the presence of pulmonary arteriovenous malformations. Survival is 75% at 15 years, despite being considered end stage.

Creation of a Brachial Arteriovenous Fistula for Treatment of Pulmonary Arteriovenous Malformations After Cavopulmonary Anastomosis

BACKGROUND

Pulmonary arteriovenous malformations (PAVMs) occur in approximately 20% of patients after unidirectional superior cavopulmonary anastomosis (CPA), and frequently after bidirectional CPA in patients with polysplenia syndrome. It is hypothesized that exclusion of a growth-modulating factor produced in the liver may predispose to PAVM formation. Resolution of PAVMs after inclusion of hepatic venous effluent into the cavopulmonary circulation has been reported. An upper extremity systemic arteriovenous (AV) fistula may be created to augment pulmonary blood flow and improve oxygenation in hypoxemic patients with CPA, but there has been no systematic investigation of the effects of such fistulas on PAVMs after CPA.

METHODS

We studied 11 patients with PAVMs who underwent creation of a brachial AV fistula a median of 11 years after CPA.

RESULTS

Eight patients had discontinuous pulmonary arteries or unilateral flow of a bidirectional CPA and were not considered good candidates for Fontan completion; the other 3 patients had polysplenia and unilateral hepatic venous streaming after Fontan completion. Three patients died of progressive complications of their heart disease 4 to 18 months after AV fistula creation. Pulmonary arteriovenous malformations resolved after creation of a brachial AV fistula in 4 of 5 surviving patients with unilateral flow of a superior CPA, but in none of 3 patients with polysplenia who had unilateral hepatic venous streaming after Fontan completion and PAVMs in the contralateral lung.

CONCLUSIONS

These findings are consistent with the "hepatic factor" hypothesis, according to which the development of PAVMs is facilitated when an unidentified factor produced or metabolized in the liver does not reach the pulmonary circulation before traversing another capillary bed. Patients with unilateral superior CPA flow and PAVMs who are not considered candidates for Fontan completion may benefit from a brachial AV fistula.