How we approach peripheral pulmonary stenosis in Williams-Beuren syndrome

Complex Pulmonary Artery Rehabilitation in Children with Alagille Syndrome: An Early Single-Center Experience of a Successful Collaborative Work

Objective: In this paper, we share our single-center experience of successful multidisciplinary management of patients with Alagille syndrome. In addition, we aim to highlight the need for an Alagille program for effectively managing these patients, in general, and particularly peripheral pulmonary artery stenosis associated with this syndrome. Study Design: This is a retrospective review of six children with Alagille syndrome and advanced liver involvement who underwent pulmonary artery reconstruction between 2021 and 2022. Cardiac diagnosis, co-existing liver disease burdens, management approach, and short-term outcomes were analyzed. Results: All the patients underwent one-stage extensive bilateral branch pulmonary rehabilitation. Concomitant procedures included repair of tetralogy of Fallot in one patient and repair of supravalvar pulmonary artery stenosis in two. One patient had balloon pulmonary branch angioplasty before surgery. In all patients, there was a decrease in right ventricular systolic pressure post-operatively. Three patients underwent liver transplantation for pre-existing liver dysfunction. At a median 3-year follow-up, all the patients were alive with their right ventricular systolic pressure less than half of their systemic systolic pressure. One patient underwent balloon angioplasty due to new and recurrent left pulmonary artery stenosis 13 months after surgery. Conclusion: Pulmonary arteries can be successfully rehabilitated surgically in the presence of complex branch disease. Patients with advanced liver disease can undergo successful complex pulmonary artery reconstruction, which can facilitate their future liver transplantation course. A multidisciplinary team approach is a key for successful management of Alagille patients.

Elastin Insufficiency Confers Proximal and Distal Pulmonary Vasculopathy in Mice, Partially Remedied by the KATP Channel Opener Minoxidil: Considerations and Cautions for the Treatment of People With Williams-Beuren Syndrome

Background

Williams Beuren syndrome (WBS) is a recurrent microdeletion disorder that removes one copy of elastin (ELN), resulting in large artery vasculopathy. Early stenosis of the pulmonary vascular tree is common, but few data are available on longer-term implications of the condition.

Methods

Computed tomography (CT) angiogram (n = 11) and echocardiogram (n = 20) were performed in children with WBS aged 3.4–17.8 years. Controls (n = 11, aged 4.4–16.8 years) also underwent echocardiogram. Eln^+/− mice were analyzed by invasive catheter, echocardiogram, micro-CT (μCT), histology, and pressure myography. We subsequently tested whether minoxidil resulted in improved pulmonary vascular endpoints.

Results

WBS participants with a history of main or branch pulmonary artery (PA) stenosis requiring intervention continued to exhibit increased right ventricular systolic pressure (RVSP, echocardiogram) relative to their peers without intervention (p < 0.01), with no clear difference in PA size. Untreated Eln^+/− mice also show elevated RVSP by invasive catheterization (p < 0.0001), increased normalized right heart mass (p < 0.01) and reduced caliber branch PAs by pressure myography (p < 0.0001). Eln^+/− main PA medias are thickened histologically relative to Eln^+/+ (p < 0.0001). Most Eln^+/− phenotypes are shared by both sexes, but PA medial thickness is substantially greater in Eln^+/− males (p < 0.001). Eln^+/− mice showed more acute proximal branching angles (p < 0.0001) and longer vascular segment lengths (p < 0.0001) (μCT), with genotype differences emerging by P7. Diminished PA acceleration time (p < 0.001) and systolic notching (p < 0.0001) were also observed in Eln^+/− echocardiography. Vascular casting plus μCT revealed longer generation-specific PA arcade length (p < 0.0001), with increased PA branching detectable by P90 (p < 0.0001). Post-weaning minoxidil decreased RVSP (p < 0.01) and normalized PA caliber (p < 0.0001) but not early-onset proximal branching angle or segment length, nor later-developing peripheral branch number.

Conclusions

Vascular deficiencies beyond arterial caliber persist in individuals with WBS who have undergone PA stenosis intervention. Evaluation of Eln^+/− mice reveals complex vascular changes that affect the proximal and distal vasculatures. Minoxidil, given post-weaning, decreases RVSP and improves lumen diameter, but does not alter other earlier-onset vascular patterns. Our data suggest additional therapies including minoxidil could be a useful adjunct to surgical therapy, and future trials should be considered.

The treatment dilemma in adult patients with peripheral pulmonary artery stenosis of diverse etiologies

Background

Peripheral pulmonary artery stenosis (PPAS) is a rare and underdiagnosed phenomenon that is reported infrequently in adult patients. Most patients with PPAS have concomitant congenital heart diseases, a history of palliative surgical therapies during childhood, or syndromic characteristics. Acquired cases are rare, and they are underestimated in adulthood and managed inappropriately.

Case presentation

This case series describes 3 adult patients with PPAS of diverse etiologies and discusses their underlying causes, diagnostic modalities, and treatment strategies.

Conclusions

In patients with PPAS, sufficient heed should be paid to endovascular interventions such as balloon dilation and primary or bailout stenting, not least vis-à-vis the type and size of balloons or stents as well as complications and preventive strategies.

Pulmonary Artery Reconstruction After Failed Pulmonary Artery Stents

BACKGROUND

Pulmonary artery stents are widely deployed in patients with stenoses in the branch pulmonary arteries. However, stents do not address more peripheral sites of stenosis and invariably develop in-stent restenosis. The purpose of this study was to review our experience with pulmonary artery reconstruction after failed pulmonary artery stents.

METHODS

This was a retrospective study of 56 patients who underwent pulmonary artery reconstruction after failed pulmonary artery stents. These patients had undergone a median of 2 (range, 0-5) previous surgical procedures and 2 (range, 1-4) pulmonary artery stents.

RESULTS

The median age at stent surgery was 5 (range, 0.3-23.6) years. The majority of stents (79%) were completely removed and patch augmented. The minority of stents (21%) were felt to be unremovable and thus were split longitudinally and reconstructed using a pulmonary artery homograft. There was 1 (1.8%) operative mortality. The mean pulmonary artery-to-aortic pressure ratio decreased from a preoperative value of 0.91 ± 0.21 to a postoperative value of 0.31 ± 0.07 (P < .001). The median hospital length of stay was 10 days. The median duration of follow-up was 1.8 years. There has been no midterm mortality. Six patients have undergone balloon dilation postoperatively for residual pulmonary artery stenosis.

CONCLUSIONS

Pulmonary artery reconstruction resulted in a significant decrease in pulmonary artery-to-aortic pressure ratios. The subsequent need for reintervention on the pulmonary arteries has been relatively low (11% to date). These results suggest that patients with pulmonary artery stents can be successfully treated with surgical reconstruction.

Surgical Techniques for Repair of Peripheral Pulmonary Artery Stenosis

Peripheral pulmonary artery stenosis is a rare form of congenital heart disease frequently associated with Williams and Alagille syndromes. Patients with this disease typically have systemic level right ventricular pressures secondary to obstruction at the lobar, segmental, and subsegmental branches. The current management of patients with peripheral pulmonary artery stenosis remains somewhat controversial. We have pioneered an entirely surgical approach to the reconstruction of peripheral pulmonary artery stenosis. This approach initially entailed surgical patch augmentation of all major lobar branches and effectively reduced right ventricular pressures by more than half. This was the first report demonstrating an effective approach to the disease. Over the past 5 years, we have gradually evolved the technique to extend the reconstruction's reach to include segmental and subsegmental branch stenoses. An important technical aspect of this approach entails division of the main pulmonary and separation of the branch pulmonary arteries to access the lower lobe branches. Pulmonary artery homograft patches are used to augment hypoplastic pulmonary artery branches. In addition, we perform a Heineke-Mikulicz type ostioplasty for isolated ostial stenoses. The technical details of the surgical approach to peripheral pulmonary artery stenosis are outlined in this article, and can also be used for other complex peripheral pulmonary artery reconstructions.

Surgical Techniques for Repair of Peripheral Pulmonary Artery Stenosis

Peripheral pulmonary artery stenosis (PPAS) is a rare form of congenital heart disease that is most frequently associated with Williams and Alagille syndromes. These patients typically have systemic level right ventricular pressures secondary to obstruction at the lobar, segmental, and subsegmental branches. The current management of patients with PPAS remains somewhat controversial. We have pioneered an entirely surgical approach for the reconstruction of PPAS. This approach initially entailed a surgical patch augmentation of all major lobar branches and effectively reduced the right ventricular pressures by more than half. This was the first report demonstrating an effective approach to this disease. Over the past 5 years, we have gradually evolved our technique of reconstruction to include segmental and subsegmental branch stenoses. An important technical aspect of this approach entails the division of the main pulmonary and separation of the branch pulmonary arteries to access the lower lobe branches. Pulmonary artery homograft patches are used to augment hypoplastic pulmonary artery branches. In addition, we perform a Heinecke-Miculicz-type ostioplasty for isolated ostial stenoses. The technical details of the surgical approach to PPAS are outlined in this article and can also be used for other complex peripheral pulmonary artery reconstructions.

Occult progressive pulmonary arterial occlusion associated with right ventricular hypertension in patients with systemic arteriopathy

OBJECTIVES

Peripheral pulmonary artery stenosis (PPS) is a heterogeneous disease associated with numerous clinical or syndromic disorders including Williams syndrome. Previous studies focusing on patients with Williams syndrome have documented spontaneous improvement in branch pulmonary artery (PA) stenosis and right ventricular pressure. The goal of this study is to identify angiographic evidence of spontaneous occlusion or loss of segmental PAs in patients with PPS.

METHODS

Patients undergoing serial catheterization for PPS at Boston Children's Hospital between 1999 and 2014 were selected. Patients with structural heart disease such as tetralogy of Fallot, truncus arteriosus, transposition of the great arteries, or single ventricle were excluded. Hemodynamic data were extracted from catheterization reports, all available angiograms were reviewed, and evidence of segmental PA loss was documented based on defined angiographic criteria.

RESULTS

Forty-two patients were included in the study. Each patient underwent an average of 5 catheterizations over the 15-year study period. The average RV pressure at initial catheterization was near systemic levels. Evidence of segmental PA loss was present in 40% of patients. Almost 30% of patients with vessel loss demonstrated loss at their initial catheterization, and 65% of patients experienced loss of multiple vessels over time. Patients with vessel loss tended to be older at initial catheterization and have higher average RV pressures at their most recent catheterization than those without vessel loss.

CONCLUSIONS

Progressive segmental PA loss in patients with systemic arteriopathy and PPS has not been well described previously. In this cohort, segmental PA loss occurred in 40% of patients, resulting in persistently elevated PA pressures relative to patients who did not develop vessel loss. These findings highlight the importance of surveillance in this population of patients with systemic arteriopathy and severe PPS.

Surgical repair of pulmonary artery branches

Surgical repair of pulmonary artery (PA) branches encompasses many different clinical scenarios and technical challenges. The most common, such as bifurcation and central PA reconstruction, are described, as well as the challenges of complex and peripheral reconstruction.