Repair of the Left Pulmonary Artery After Bilateral Banding in Hybrid Procedures

Introduction

Surgical and catheter-based interventions for congenital heart disease (CHD) have evolved remarkably over the past 50 years. During the last decade, more centers are embracing the hybrid approach for the initial palliation of neonates born with hypoplastic left heart syndrome (HLHS) or its variants. Bilateral branch pulmonary arterial banding (BPAB) is an effective method for the control of pulmonary blood flow in ductal-dependent lesions. It is performed initially both as part of a comprehensive strategy for hybrid palliation and in selected cases to stabilize patients in the immediate postnatal period with pulmonary overcirculation and ductal-dependent blood flow. ¹ Pulmonary arterial banding has important consequences on the vascular wall that may result in a significant long-term impact to pulmonary arterial growth potential. ¹ Acquired postoperative pulmonary branch stenosis has been encountered after debanding, and several techniques have been described for treatment. ^1,2 We report a surgical technique based on the concept of “sutureless” repair (patch augmentation) of the region of the left pulmonary artery (LPA) stenosis after debanding using autologous pericardium, with the aim of decreasing the risk of restenosis. It is acknowledged that technically speaking, the term sutureless is a misnomer, as the fixation of the angioplasty patch is certainly accomplished using sutures. But, as in the technique or sutureless repair of pulmonary vein stenosis, which is gaining increasing acceptance among practitioners, our method of pulmonary artery patch angioplasty involves securing the patch by placement of sutures within the vessel adventitia and surrounding tissues at some distance from the pulmonary arteriotomy incision itself, rather than through the full thickness of the cut edge of the arterial wall.

Patients and Methods

A retrospective review from medical records was performed. The study has been approved by the institutional review boards of the respective hospital of each patient.

Surgical Technique

As part of the procedure, the LPA was reconstructed in both patients. The operation was performed via repeat median sternotomy. Cardiopulmonary bypass was instituted with pulmonary artery and right atrial cannulation. Deep hypothermic circulatory arrest was instituted at a temperature of 18°C. During the cooling phase with beating heart, dissection was carried out to expose the BPAB. Previously placed 1-mm-width polytetrafluoroethylene (W. L. Gore & Associates, Inc, Flagstaff, Arizona) bilateral bands were cut and removed. An oval-shaped piece of fresh autologous pericardium was tailored. Several delicate 7-0 polypropylene stiches were placed in the pulmonary artery adventitia, and the adjacent pericardium and fibrotic tissue at least 1 mm from the edge of a longitudinal arteriotomy which was made at the site from which the band had been removed. Great care was exercised in avoiding the placement of sutures in the intima at the cut edge of the vessel (Figure 1). A 5 mm probe was easily passed through the augmentation area after the repair.

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Figure 1.

Schematic showing left pulmonary artery reconstructions with autologous pericardium (AP) utilizing the so-called “sutureless” technique (insert) after debanding during comprehensive stage 2 for patient 1.

Results

Both patients survived the operation. For patient 1, the postoperative course was complicated by bleeding, junctional ectopic tachycardia, delayed chest closure, low cardiac output, and sepsis. Extubation to noninvasive ventilation was accomplished at day 17 and weaning to room air at day 24. Routine exit pulmonary angiography before discharge revealed good flow across the left pulmonary arterioplasty site (Figure 2). A large azygos to the inferior vena cava venovenous decompressing collateral was found and successfully coiled. Arterial saturation improved to 80%, and the patient was discharged home 48 days after the operation. At nine months of age, the patient’s saturation by pulse oximetry was 89% in room air. Regarding patient 2, the postoperative course was complicated with bleeding, delayed chest closure, mediastinitis, prolonged mechanical ventilation, and chylothorax. At seven months of age, a superior cavopulmonary anastomosis was performed in addition to takedown of the right-modified Blalock–Taussig. Three weeks after the Glenn anastomosis was performed, successful balloon catheter angioplasty was done to treat an aortic coarctation. Selective pulmonary angiography revealed no stenosis of the LPA after repair. The patient was discharged from hospital at 8 months of age. Echocardiogram at 24 months of age revealed adequate right ventricular function, and peripheral saturation breathing room air was 79%.

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Figure 2.

Exit angiography for patient 1 revealing adequate caliber with normal flow across the left pulmonary arterioplasty area.

Comment

Use of the hybrid approach has evolved from a “surgical bailout procedure” to now being considered an important alternative treatment strategy in the management of patients with CHD for which there are no ideal isolated interventions. These types of procedures have both expanded the therapeutic options for patients with specific congenital heart defects and reduced the number and duration of required interventions. After initial hybrid palliation, the comprehensive stage 2 palliation for HLHS is generally performed at approximately 4 to 6 months of life, usually with the patient weighing ≥5 kg and includes debanding of the branch pulmonary arteries, atrial septectomy, bidirectional Glenn anastomosis, Damus–Kaye–Stansel anastomosis, and usually arch reconstruction. Adequacy of pulmonary artery growth has been a question after the hybrid strategy for HLHS palliation, in comparison to stage 1 Norwood strategies, as these strategies may have different and potentially important sequelae in terms of anatomic and physiologic growth stimuli to the pulmonary arteries. Honjo et al ³ from Toronto reported their experience, indicating that the hybrid palliation does not have a significant adverse impact on the pulmonary artery development, with comparable pulmonary artery growth, hemodynamics, equivalent survival, and diminished hospital utilization. Nevertheless, the same group at the Hospital for Sick Children ⁴ has recently reported that hybrid patients in their experience had a higher pulmonary artery reintervention rate and lower Nakata index at pre-Fontan evaluation.

In this article, we report our experience with the so-called sutureless repair technique for LPA angioplasty after pulmonary artery debanding in two patients with HLHS.

Patients undergoing BPAB placement may require early and repeated operative and catheter-based interventions after BPAB removal. ¹ Conventional BPAB with expanded polytetrafluoroethylene tape has high risks of residual PA stenosis after debanding. ⁵ The risk of LPA stenosis has been reported from 2.5% up to 40% according to different surgical groups. ⁶ Techniques described to manage pulmonary artery stenosis after debanding include patch arterioplasty, excision and reconstruction of a pulmonary artery segment, rigid or balloon dilation, or placement of a stent via an open surgical procedure (so-called “hybrid approach”). ^1,2 Although sutureless repair technique has been successfully applied for pulmonary vein stenosis, ⁷ to the best of our knowledge, the principle has not been applied for pulmonary arterioplasty after debanding.

To address this problem, the objective of the proposed technique is to avoid residual pulmonary artery stenosis at the debanded segment by enlarging the area with a patch of autologous pericardium and specifically by suturing it to the surrounding pulmonary artery adventitia tissue, with the rationale that with the use of this technique, the risk of restenosis may decrease. It has been a policy for our group to perform a similar technique to decrease the incidence of LPA stenosis in other lesions such as pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.

This technique is intended to decrease the risk of residual stenosis at the debanded segment by enlarging the area with a pericardial patch sutured to the surrounding pulmonary artery adventitia tissue, with the rationale that growth potential will be optimized. We prefer fresh autologous pericardium because glutaraldehyde-fixed pericardium can predispose to a mild degree of calcification over the long term and may be a disadvantage if there is hope that the patch might enlarge with time, thereby giving the appearance of growth. ⁸

Although the postoperative course of these patients has been complex and the follow-up time is limited, no restenosis was detected at 4 and 16 months for patients 1 and 2, respectively. As protocol, the group has instituted exit angiography in order to rule out stenosis at the time of the comprehensive stage 2 procedure.

In conclusion, we believe that the so-called sutureless technique for stenosed pulmonary artery reconstruction is simple, reproducible, and may decrease the incidence of residual stenosis after pulmonary arterial banding removal following a hybrid approach. Although we had good results in the very short term, longer follow-up and larger numbers of patients are needed to assess the late and ultimate clinical results of this technique.