Pulmonary Arteriovenous Malformation in an Unrepaired Tetralogy of Fallot: Diagnostic Implications

Development of pulmonary arteriovenous malformation (PAVM) is not uncommon following Glenn repair for patients with congenital heart diseases; however, its occurrence with unrepaired tetralogy of Fallot (TOF) is rarely reported. The present case highlights this rare occurrence of PAVM in unrepaired TOF along with its potential diagnostic implications. Computed tomography angiography images from an adult patient with TOF showed its classic imaging features, including the presence of subaortic ventricular septal defect with aortic override, infundibular and valvular pulmonary stenosis, and right ventricular hypertrophy. Pulmonary arteries were confluent with hilar right and left pulmonary arteries measuring 18 mm and 19 mm, respectively. Multiple significant aortopulmonary collaterals were seen arising from the proximal descending thoracic aorta, bilateral subclavian, and bilateral internal mammary arteries. Interestingly, it showed the presence of multiple collaterals along the right upper posterolateral chest wall (with hypertrophied and tortuous upper right posterior intercostal and lateral thoracic arteries) with the presence of PAVM in the superior segment (segmental artery diameter: 2.8 mm) of the right lower lobe (Figure 1). The aortic arch was right-sided with a mirror image branching pattern. Systemic and pulmonary venous drainage was normal. No patent arterial duct, anomalous coronary artery, or coarctation of the aorta was seen. Pulmonary arteriovenous malformation is characterized by the presence of abnormal communication of pulmonary arteries and veins with no intervening capillary bed.1Meek M.E. Meek J.C. Beheshti M.V. 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If the PAVM is significant, one would expect postoperative cyanosis, at which point occlusion of the PAVM might be considered rather than focusing on lung parenchymal issues. In the present case, it is difficult to determine if the PAVM is associated with the unrepaired TOF or if it is simply a second coexisting congenital abnormality, but this rare combination highlights the need for a thorough preoperative work-up as well as a high index of suspicion. The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article. This work was not supported by funding agencies in the public, commercial, or not-for-profit sectors.