Pulmonary Arterial Stent for Pulmonary Trunk Stenosis After Size-Mismatched Lung Transplantation
Lung transplantation is a life-saving procedure for patients with end-stage lung diseases. However, the success of this procedure heavily depends on several factors, including the appropriate size matching between the donor and recipient lungs. Size mismatches can lead to complications such as pulmonary trunk stenosis, which can significantly impact the patient’s post-transplant recovery and quality of life. This article presents a detailed case study of a patient who developed pulmonary trunk stenosis after a size-mismatched lung transplantation and the subsequent treatment with pulmonary arterial stents.
Case Presentation
The patient was a 57-year-old male with a 4-year history of pulmonary fibrosis. He underwent a right single lung transplantation from a brain-dead donor through the China Organ Transplant Response System in March 2018. The donor was slightly larger than the recipient, with a height of 175 cm and a weight of 80 kg, compared to the recipient’s height of 172 cm and weight of 72 kg. The transplantation was performed under extracorporeal membrane oxygenation (ECMO) assistance. ECMO and tracheal intubation were discontinued on postoperative days 2 and 3, respectively.
Postoperative Complications
Two weeks after the transplantation, the patient began to experience progressive dyspnea. Initial investigations ruled out infectious causes through chest computed tomography (CT) scanning, bronchoscopy, and laboratory tests. Echocardiography revealed moderate pulmonary hypertension with a pressure of 52 mmHg. Pulmonary artery CT angiography showed stenosis at the level of the right lower pulmonary trunk and a tiny left lower pulmonary artery thrombus.
Diagnostic Workup
The patient was treated with anticoagulant therapy (Enoxaparin, 6000 IU, every 12 h) for two weeks, but his symptoms worsened. Further diagnostic workup included right cardiac catheterization and pulmonary angiography, which confirmed severe stenosis of the distal right pulmonary trunk. The right middle lobe and lower lobe pulmonary arteries were not clearly visualized, while other branches of the pulmonary artery showed no obvious stenoses, occlusions, or filling defects.
Treatment Strategy
Initial treatment involved serial balloon dilation, but elastic retraction occurred, and oxygen saturation could not be maintained above 90%. The patient was reintubated, placed under ECMO, and transferred to the intensive care unit. Three days later, another pulmonary angiography revealed a 90% stenosis of the right pulmonary trunk. Balloon dilation (Aviator 6.0 mm × 20.0 mm, 14 atm) was performed, followed by the sequential implantation of two stents (Palmaz Blue 7.0 mm × 18.0 mm, 18 atm; Palmaz Genesis 8.0 mm × 24.0 mm, 20 atm; Johnson & Johnson Interventional Systems, Warren, NJ, USA). One stent was placed in the pulmonary trunk, and the other was stretched across the stenotic section.
Outcome
Post-stent implantation pulmonary angiography demonstrated residual stenosis of less than 25% of the lumen. The right pulmonary arterial pressure decreased from 70/24 to 35/16 mmHg and stabilized at approximately 55/20 mmHg. The stents were fixed in place with no displacement observed. The patient’s oxygen saturation improved immediately after the procedure, and he was extubated in the operating room. ECMO was removed on postoperative day 3. Follow-up pulmonary artery CT angiography showed the stents in proper position with no apparent narrowing of the pulmonary trunk. The patient recovered well and is currently living a normal life under continuous follow-up monitoring.
Discussion
Size matching between donors and recipients is a critical factor in lung transplantation. Although lung tailoring and lobar transplantation have been advocated to address size disparities, these procedures can lead to complications such as pulmonary trunk stenosis. In this case, the stenosis was likely caused by the resection of the right middle lobe, which was performed to achieve better size matching. The donor’s relatively larger lung size and the recipient’s smaller thoracic cavity may have contributed to the twisting and angulation of the pulmonary trunk, leading to stenosis.
Diagnostic and Therapeutic Approach
The diagnostic protocol included echocardiography, pulmonary artery CT angiography, and right cardiac catheterization, which were instrumental in identifying the cause of the patient’s dyspnea. The treatment strategy involved balloon dilation and stent implantation, which proved effective in resolving the stenosis. However, the procedure required careful attention to elastic retraction and the potential need for reintubation and ECMO support.
Role of ECMO
ECMO played a crucial role in the perioperative management of this patient. It provided essential support during the initial transplantation and the subsequent treatment of pulmonary trunk stenosis. The use of ECMO allowed for the stabilization of the patient’s condition, enabling the successful implantation of stents and the eventual recovery of the patient.
Conclusion
Pulmonary trunk stenosis is a rare but serious complication that can occur after size-mismatched lung transplantation. The case highlights the importance of appropriate size matching and the potential complications of lung tailoring procedures. Pulmonary angiography and stent implantation are effective diagnostic and therapeutic methods for managing this condition. The successful outcome in this case underscores the value of a multidisciplinary approach, including the use of ECMO, in the management of complex post-transplant complications.
doi.org/10.1097/CM9.0000000000000209
Was this helpful?
0 / 0