A 16-year-old Japanese male without any symptoms was admitted to our hospital in April 2010 for routine annual hemodynamic, angiographical, and histological follow-up after cardiac transplantation. In 2004, he was diagnosed with dilated cardiomyopathy after complaining of progressive severe malaise. As congestive heart failure rapidly progressed for 2 months despite maximal medical therapy, a left ventricular assist device (Toyobo-NCVC LVAD, Toyobo, Osaka, Japan) was inserted as a bridge to cardiac transplantation. In March 2005, he underwent a heart transplant in the United States using the heart from an 18-year-old white male who had died due to head trauma. The ratio of body weight of the donor to that of the recipient was >200%. As the donor heart was considered to be relatively large for the recipient, the size-mismatch donor heart was successfully transplanted by pericardectomy. Thereafter, cyclosporine and mycophenolic acid were administered as immunosuppressive agents with meticulous dose adjustment in accordance with therapeutic drug monitoring. Meanwhile, other than slow development of mild renal dysfunction caused by the immunosuppressants, his general post-transplant clinical course was uneventful for 2 years. Annual hemodynamic, coronary angiographic, and intravascular ultrasound studies demonstrated no evidence suggesting hemodynamic instability or allograft vasculopathy until 4 years after the transplantation. In addition, electrocardiograms continuously showed no evidence of myocardial damage for 6 years since transplantation. Histological follow-up by evaluating samples achieved by endomyocardial biopsy primarily from the interventricular septum of the right ventricle using bioptome through 6.5-F seath approached from femoral vein at 2 and 6 months and 1, 2, 3, and 4 years after the transplant continuously revealed neither cellular nor vascular cardiac allograft rejection (Rejection grade of the International Society for Heart and Lung Transplantation1; 0).
As in previous examinations, allograft rejection was not evident in cardiac specimens examined in April 2010 (6 years after transplant). However, coronary angiograms demonstrated apparent progression of a complex aggregation of screwed coronary artery-pulmonary artery fistula (Figure 1, arrow head) (see Video, Supplemental Digital Content 1, http://links.lww.com/ASAIO/A4), which was first noted at the 2006 annual examination (2 years after transplant) (see Video, Supplemental Digital Content 2, http://links.lww.com/ASAIO/A5). The fistula, which was not visible in 2006, was partly fed by progressive arteries that originated from the right coronary artery (Figure 1, arrows). Arteries feeding the fistula originated from the right ventricular branches of the right coronary artery (RCA) and branches of the left anterior descending (LAD) coronary artery, and it drained into the peripheral left pulmonary artery. Contrast-enhanced computer tomography (CT) showed that the fistula was located over a wide range in the anterior to lateral surface of the right ventricle (Figure 2). Right heart catheterization in 2010 showed step-up in oxygen saturation (SpO2) from 68.7% in superior vena cava (SVC) to 78.0% in left pulmonary artery, despite no significant elevation in Qp/Qs ratio (1.16) in comparison to that in 2009 (1.13).
Complications in association with cardiac transplantation could be critically important not only for patients after that but also for patients before that with ventricular assist device. It has been reported that the prevalence of coronary artery fistula after cardiac transplantation was significantly higher (5%–14%)2,3 than that in the general population.4 Although the precise cause of the higher incidence of coronary artery fistulas in a post-transplant setting remains unclear, multiple tissue injury due to repeated endomyocardial biopsy in the right ventricle has been considered as the best possible explanation and is supported by the fact that almost all coronary fistulas in post-transplant settings drain into the right ventricle. One case series of transplant-related coronary artery fistulas showed that most of the feeding arteries arose from the RCA or LAD and rarely from the left circumflex (LCx) coronary artery, and further that all the fistulas drained into the right ventricle.3 On the other hand, cases of coronary artery fistula communicating pulmonary artery have been rarely reported.5 In a follow-up survey of coronary artery fistulas after cardiac transplantation,2 the clinical, angiographical, and hemodynamic sequelae of the transplant-related coronary artery fistulas were generally favorable without specific symptoms attributable to that and higher cardiac output. The survey showed that most became undetectable, indicating spontaneous closure in accordance with the time course without hemodynamic complications, and none increased in size. On the contrary, angiographical course of the coronary artery fistula in the present case was progressive. The fistula was first noticed 2 years after transplant and it gradually but apparently enlarged and progressed in density. Furthermore, the fistula in this case was located on the front part of the right and left ventricles and originated mostly from multiple right ventricular branches of the RCA and drained into the left pulmonary artery accompanied by significant O2 step-up and not into the right ventricle. Therefore, in consideration of such anatomical features, it was not plausible that the coronary artery-pulmonary artery fistula in this case was caused by endomyocardial biopsies usually communicating with the right ventricle in post-transplant cases. In this case, surgical procedures, such as pericardectomy at the time of cardiac transplant and the placement or the removal of LVAD, might be associated with the fistula formation via local activation of angiogenic factors induced by inflammation and tissue adhesion. Surgical removal or interventional therapeutic embolization may be considered if symptoms caused by deterioration of hemodynamics or coronary steal syndrome will be present in this case.
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