A Rare Congenital Disorder in an Elderly Patient: Bilateral Anomalous Pulmonary Venous Drainage With Pulmonary Hypertension

Abstract

Anomalous pulmonary venous drainage (APVD) is a rare congenital disorder with pulmonary vein drainage into systemic circulation. We present a case of APVD with bilateral upper lobe venous drainage into the SVC and coexisting post capillary pulmonary hypertension. CASE PRESENTATION:A 72-year old gentleman with Down syndrome and cognitive impairment presented to pulmonary clinic for evaluation of pulmonary hypertension and dyspnea. It was difficult to discern by history, if reported symptoms were related to deconditioning or a result of dyspnea from cardiopulmonary disease. Exam was overall benign. However, 6-minute walk test was abnormal and revealed hypoxemia after 3 minutes, requiring 2 liters of supplemental oxygen by nasal cannula. Echocardiogram showed RVSP of 44 mmHg, enlarged RV with decreased LV internal cavity size and preserved ejection fraction. A contrast chest CT (Figure 1) showed partial APVD of the right upper lobe into the SVC and left upper lobe with APVD into the subclavian vein and into SVC (Figure 2). A right heart catheterization performed showed right atrial pressure of 16 mmHg, mean pulmonary artery pressure of 40 mmHg, wedge pressure of 20 mmHg, cardiac output of 7.5 L/min, pulmonary vascular resistance of 2.6 Wood units. Oxygen saturation showed IVC 76%, SVC 99%, RA 84%, RV 83%, PA 83%, PA wedge 87%. Shunt fraction (Qp:Qs) was calculated at 1.3. Furosemide was started to decrease preload. The patient was then referred to structural cardiology for repair of the defect due to progression of PH and RV dysfunction.DISCUSSION: Partial APVD, in contrast to total APVD, occurs when a proportion of pulmonary venous blood bypasses the left atrium, resulting in an abnormal shunt fraction. The prevalence of partial APVD is between 0.4 to 0.7%.1 A shunt fraction is abnormal when either it is greater than 1 (left to right shunt), or less than 1 (right to left shunt). In our patient, the failure of embryological tissue migration resulted in partial APVD, leading to increased systemic return to the RV, and over time resulting in RV dysfunction, potentially fatal. For this reason, it is important that the defect gets repaired to prevent future major cardiac event.CONCLUSIONS: While majority of literature report partial APVD to anomalous systemic circulation, to our knowledge this is the first reported case of bilateral partial APVD to an anatomically normal systemic circulation.