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A 46-Year-Old Man With Dyspnea, Hypoxemia, and Radiographic Asymmetry After Redo Bilateral Lung Transplantation FREE TO VIEW

Sofya Tokman, MD; Michael A. Smith, MD; A. Samad Hashimi, MD; Ashraf Omar, MD
Author and Funding Information

aDivision of Pulmonary and Critical Care Medicine, Norton Thoracic Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ

bDivision of Thoracic Surgery, Norton Thoracic Institute, St. Joseph’s Hospital and Medical Center, Phoenix, AZ

CORRESPONDENCE TO: Sofya Tokman, MD, Norton Thoracic Institute, St. Joseph’s Hospital and Medical Center, 500 W Thomas Rd, Ste 500; Phoenix, AZ 85013


Copyright 2016, American College of Chest Physicians. All Rights Reserved.


Chest. 2017;151(4):e91-e94. doi:10.1016/j.chest.2016.09.013
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Published online

Case Presentation  A 46-year-old man underwent redo bilateral sequential lung transplantation for rapidly progressive bronchiolitis obliterans syndrome that developed 3.5 years after initial transplantation. In the operating room, he was sedated and intubated with a dual lumen endotracheal tube with subsequent single right-lung ventilation and left allograft implantation. His pulmonary arterial pressure became elevated with reperfusion of the newly implanted left lung, which required initiation of cardiopulmonary bypass to facilitate implantation of the right lung. After implantation and reperfusion of the right lung, the patient was weaned from cardiopulmonary bypass. His chest was closed and he was transferred to the thoracic intensive care unit. On arrival to the intensive care unit, the patient was intubated, sedated, and had an oxygen saturation of 92% on a fraction of inspired oxygen of 100%, positive end-expiratory pressure of 10 cm H2O, and 20 parts per million of inhaled nitric oxide. He had a Swan-Ganz catheter in the right internal jugular vein that measured a mean pulmonary arterial pressure of 33 mm Hg and a pulmonary arterial systolic pressure of 63 mm Hg, which remained persistently elevated and prompted further diagnostic evaluation.

Figures in this Article

On physical examination, the patient’s vital signs were notable for a heart rate of 110 beats per minute; a BP of 100/47 mm Hg on milrinone, norepinephrine, and vasopressin; and a temperature of 36.9°C. He had a regular cardiac rhythm without murmurs, heaves, or gallops; bilateral rhonchial breath sounds; and a soft abdomen with diminished bowel sound and no hepatosplenomegaly. His clamshell incision was clean, his skin was not mottled, and his extremities were warm and well perfused. After sedation was withheld, he awoke and was able to move all extremities and follow commands appropriately.

A transesophageal echocardiogram showed elevated flow velocity of the right upper and right lower pulmonary veins. The normal pulmonary venous flow velocity (PVFV) is < 100 cm/s, but his right upper and right lower PVFVs were 146 and 136 cm/s, respectively, and his left upper and left lower PVFVs were 108 and 103 cm/s, respectively. A chest radiograph (Fig 1) performed immediately after transplantation was notable for asymmetric pulmonary infiltrates with hyperemia of the right lung and hyperlucency of the left lung. A quantitative perfusion scan showed asymmetric perfusion with 77.1% of blood flow directed toward the right lung (Fig 2). Figure 3 shows a representative image from a CT angiogram.

Figure 1
Figure Jump LinkFigure 1 Postoperative chest radiograph shows asymmetric pulmonary infiltrates with hyperemia of the right lung and hyperlucency of the left lung. Used with permission from Norton Thoracic Institute, Phoenix, Arizona.Grahic Jump Location
Figure 2
Figure Jump LinkFigure 2 Differential perfusion scan shows asymmetric perfusion, with most blood flow directed toward the right lung. Used with permission from Norton Thoracic Institute, Phoenix, Arizona.Grahic Jump Location
Figure 3
Figure Jump LinkFigure 3 CT angiogram shows a representative cut of the left main pulmonary artery. Used with permission from Norton Thoracic Institute, Phoenix, Arizona.Grahic Jump Location

What is the diagnosis?

Diagnosis: Left pulmonary artery anastomotic stenosis

Development of pulmonary hypertension with reperfusion of a newly transplanted lung allograft is pathologic and is most commonly caused by primary graft dysfunction (PGD). PGD refers to allograft injury within 72 hours of transplant; it is characterized by pulmonary edema with diffuse alveolar damage that manifests clinically as hypoxemia and bilateral infiltrates on chest radiograph. PGD has a reported incidence of 10% to 25% and leads to pulmonary hypertension via hypoxemia-mediated vasoconstriction. The presence of hypoxemia and pulmonary hypertension without radiographic pulmonary infiltrates, or with markedly asymmetric pulmonary infiltrates, points away from PGD and toward possible vascular complications.

Asymmetric radiographic appearance of the lungs immediately after lung transplantation is not uncommon, and the lung implanted first typically appears more hyperemic. This is because of the lower pulmonary vascular resistance of the allograft relative to the native lung, which drives hyperperfusion of the allograft and resultant pulmonary edema and radiographic hyperemia. Notably, in the patient presented, the left allograft was more lucent than the right allograft even though the left was implanted first. This radiographic finding raises the possibility of either left pulmonary arterial or right pulmonary venous stenosis. In the case of pulmonary arterial stenosis, the ipsilateral lung may appear radiographically hyperlucent; in pulmonary venous stenosis, the ipsilateral lung may have hazy opacities because of increased vascular congestion. A patient with either arterial or venous stenosis will be hypoxemic as a result of ventilation-perfusion mismatch, and hypoxemia may be particularly severe in patients with a single lung transplant because of shunting of blood toward the diseased native lung and away from the allograft.

Vascular anastomotic stenosis or obstruction complicates < 2% of lung transplant surgeries. Although these complications are uncommon, they carry significant morbidity and mortality; therefore, early identification and repair is crucial. Proposed risk factors for vascular anastomotic complications include donor-size mismatch and surgical technique (eg, excessively long vascular structures, inappropriate vascular orientation, hilar misalignment, overzealous suture tightening). Pulmonary arterial obstruction or severe narrowing can lead to ipsilateral ischemia with contralateral hyperperfusion, whereas venous obstruction or severe narrowing can lead to ipsilateral vascular congestion.

Ideally, vascular complications are diagnosed intraoperatively, thereby reducing the degree of allograft ischemia and injury. At our center, each transplant recipient undergoes an intraoperative transesophageal echocardiogram to measure PVFV, which increases with venous narrowing or obstruction. Notably, the patient developed elevated right PVFV from a narrowed left arterial anastomosis because of right-sided hyperperfusion. Therefore, an elevated PVFV should first prompt investigation of the venous anastomoses, with subsequent examination of the arterial anastomoses if no venous abnormality is identified. Perfusion scans and contrast CT scans of the chest are additional diagnostic tools; however, they cannot be used intraoperatively, thereby delaying diagnosis of vascular anastomotic complications.

Treatment of vascular anastomotic stenosis has been well described by Siddique et al and depends on the degree of stenosis, the degree of allograft injury, and the elapsed time between implantation and diagnosis. Cases of arterial stenosis identified intraoperatively can be corrected before the patient leaves the operating room, whereas cases identified after several weeks can be amenable to balloon angioplasty and stent placement. The management of cases identified within 2 weeks of transplantation is less certain. In the early postoperative period, balloon angioplasty may lead to vascular perforation and stents may migrate, because of incomplete anastomotic healing and respiratory and hemodynamic fluctuations, accordingly (although reports of successful stent placement in this setting exist). These risks need to be balanced with the risks of recurrent allograft ischemia, hemostasis-induced intravascular thrombosis, and ischemia-reperfusion injury associated with open repair.

Clinical Course

On postoperative day 18, we elected surgical repair of the stenosed left pulmonary artery to avoid the risks associated with balloon angioplasty or stenting. A simple revision of the anastomosis was attempted; however, reduced left-sided perfusion persisted because of pulmonary arterial size mismatch. Ultimately, a left pulmonary arterioplasty was performed using a bovine pericardium with resultant anastomotic widening and resolution of pulmonary hypertension. One month after the repair, a repeat perfusion scan showed 45% of blood flow directed to the left and 55% of blood flow directed to the right. The patient made a full recovery and now enjoys an excellent quality of life and exercise tolerance.

  • 1.

    In the absence of PGD, significant pulmonary hypertension after lung transplantation should raise suspicion for a pulmonary vascular anastomotic complication.

  • 2.

    A post-transplant increase in PVFV, measured via transesophageal echocardiography, may indicate a problem within the ipsilateral pulmonary vein or, as illustrated in this case, the contralateral pulmonary artery.

  • 3.

    Persistent asymmetric appearance of the lungs on chest radiograph immediately after bilateral sequential lung transplantation should prompt investigation for abnormalities within the vascular anastomoses.

  • 4.

    An elevated PVFV should first prompt investigation of the venous anastomoses, with subsequent examination of the arterial anastomoses if no venous abnormality is identified.

  • 5.

    CT angiography and differential perfusion scans are additional tools for screening for pulmonary arterial and venous anastomotic complications.

Financial/nonfinancial disclosures: The authors have reported to CHEST the following: M. A. S. has received educational grants from Ethicon Endosurgery for providing teaching to other surgeons for video-assisted thoracoscopic surgery (VATS) lobectomy courses. None declared (S. T., A. S. H., A. O.).

Other contributions:CHEST worked with the authors to ensure that the Journal policies on patient consent to report information were met.


Figures

Figure Jump LinkFigure 1 Postoperative chest radiograph shows asymmetric pulmonary infiltrates with hyperemia of the right lung and hyperlucency of the left lung. Used with permission from Norton Thoracic Institute, Phoenix, Arizona.Grahic Jump Location
Figure Jump LinkFigure 2 Differential perfusion scan shows asymmetric perfusion, with most blood flow directed toward the right lung. Used with permission from Norton Thoracic Institute, Phoenix, Arizona.Grahic Jump Location
Figure Jump LinkFigure 3 CT angiogram shows a representative cut of the left main pulmonary artery. Used with permission from Norton Thoracic Institute, Phoenix, Arizona.Grahic Jump Location

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