Keywords:
Transplantation, Surgery, CT, Thorax, Lung
Authors:
Y. Choi, W. H. Cho, D. H. Kim; Yangsan/KR
DOI:
10.26044/esti2019/P-0049
Imaging findings OR procedure details
1> Mechanical complication
Size mismatch between donor lung and recipient thoracic cage may induce this problem.
Size differences within 25% have been reported as acceptable.
Too large donor lung may induce atelectasis and impaired ventilation,
and too small donor lung may lead to graft hyperexpansion.
The large graft may be reduced intraoperatively for size matching.
(Fig.1)
2> Airway complications
Airway complications are mostly due to donor bronchus ischemia,
caused by disruption of native bronchial circulation.
- Bronchial dehiscence : Bronchial dehiscence is the most common airway complication in the early postoperative period. On CT scan,
presence of extraluminal gas,
focal bronchial wall defect can be seen.
Presence of persistent air leak or pneumothorax is indirect sign of bronchial dehiscence. (Fig.2)
- Bronchial stenosis and stricture : Bronchial stenosis and stricture are mostly related to ischemia and inflammation,
due to suboptimal vascular supply,
and most commonly seen at bronchus intermedius. (Fig.3)
3> Vascular complications
- Anastomotic site stenosis : Anastomotic site stenosis is more common at arterial site.
CT scan may show narrowing of pulmonary artery and pulmonary opacities related to lung infarction.
- Thromboembolism :Thromboembolism is a common complication and associated with hypercoagulable state,
due to the inflammatory response to the donor organ. (Fig.4)
4> Pulmonary parenchymal or pleural complications
- In the early postoperative period (beween 24 hour–1 week),
- Primary graft dysfunction : Also known as reperfusion injury or reimplantation response.
This is a form of non-cardiogenic pulmonary edema that occurs in more than 90% of patients.
It usually appears within 3 days of transplantation and improves by the end of the 1st week.
Chest CT shows bilateral perihilar ground glass opacities,
bronchovascular thickening and interstitial thickening predominantly in middle and lower lobes. (Fig.5)
- Pleural complication : Pneumothorax,
hemothorax,
pleural effusion,
empyemas are commonly seen in the early postoperative period,
with a reported frequency of 22-34%.
(Fig.6)
- In the intermediate postoperative period (8 day-2 months),
- Acute rejection : This occurs due to cell-mediated immune response.
Early and repeated episodes of acute rejection is a risk factor for chronic rejuction.
CT findings are nonspecific,
but typical findings may include basal predominant ground blass opacities,
peribronchial or interstitial thickening and pleural effusions.
Transbronchial biopsy is diagnostic choice.
(Fig.7)
- Pulmonary infections : Infections are the most common complication and a major cause of morbidity and mortality.
Bacterial infections by Gram negative bacteria(Pseudomonas,
Klebsiella) are common within the first month after transplantation.
Fungal infections(most commonly Candida and Aspergillus) are also common within two months after transplantation.
Among viral infection,
cytomegalovirus(CMV) is most common,
with a peak incidence of 1-4 months.
Mycobacterial infections are relatively uncommon and usually occur in late postoperative period,
4months after surgery.
(Fig.
8)
- Late postoperative period (2 months - ),
- Chronic Lung Allograft dysfunction (CLAD) : CLAD is the major late complication,
with 40-50% of prevalence within 5 years after transplantation.
Two distinct phenotypes are included in CLAD; bronchiolitis obliterans syndrome (BOS) and restrictive allograft syndrome(RAS),
respectively.
On CT,
BOS show bronchiectasis,
bronchial wall thickening,
expiratory air trapping.
On the other hand,
RAS may show central or peripheral ground glass opacities,
coarse septal lines,
traction bronchiectasis and peribronchial nodular opacities.
(Fig.
9)
- Posttransplantation lymphoproliferative disorder (PTLD) : PTLD is a spectrum of diseases that vary from benign lymphoid proliferation to high grade lymphoma.
The reported incidence is less than 5 %.
Common risk factor is Ebstein-Barr vius infection,
associated with immunosuppression.
CT shows solitary or multiple lung nodules/masses with or without lymphadenopathy or pleural effusion.
(Fig.
10)