B50-21 When the Lungs Drain the Wrong Way: A Pulmonary Venous Anomaly Challenging ICU Care

Abstract Partial Anomalous Pulmonary Venous Return (PAPVR) is a rare congenital anomaly affecting approximately 0.4-1% of the population, with over half of cases remaining asymptomatic. It occurs when one or more pulmonary veins drain into the right atrium or systemic venous circulation instead of the left atrium, creating a left-to-right shunt. This case describes a rare and severe presentation of a patient with cardiogenic shock secondary to PAPVR, requiring intensive management and challenging hemodynamic support. A 51-year-old male with past medical history of severe pulmonary hypertension, and obesity hypoventilation syndrome, presented with one week of progressive dyspnea, abdominal distension, and bilateral leg edema. He denied chest pain, fever, or gastrointestinal symptoms. Review of outside medical records revealed congenital PAPVR, resulting in a left-to-right shunt (Qp/Qs 2:1) and right ventricular systolic pressure (RVSP) of approximately 80 mmHg. On admission, he required BiPAP for hypercapnic respiratory failure but later deteriorated, requiring intubation and ICU transfer. Chest radiography showed cardiomegaly and pulmonary congestion, while echocardiography demonstrated a preserved left ventricular ejection fraction (72%), severe right ventricular dilation, reduced systolic function, and septal flattening consistent with RV pressure overload. He developed acute heart failure and cardiogenic shock, managed with milrinone, vasopressors, and aggressive diuresis. Following stabilization, he was extubated, weaned off pressors, and discharged in improved condition. He was to follow-up outpatient to begin the process for surgical correction, as he met criteria for repair. This case illustrates the challenges in managing PAPVR. Although most cases are asymptomatic, hemodynamically significant PAPVR requires careful management to prevent decompensation. The resulting left-to-right shunt leads to chronic right-sided volume and pressure overload, which may progress to right heart failure and cardiogenic shock. Interventricular dependence further reduces left ventricular filling, stroke volume, and systemic perfusion. Management of cardiogenic shock from right ventricular (RV) failure involves balancing preload, afterload, contractility, and mean arterial pressure (MAP). Diuresis relieves congestion, while norepinephrine supports MAP without increasing pulmonary vascular resistance. Because the RV is highly sensitive to pulmonary pressure changes, treating pulmonary hypertension with sildenafil and milrinone is crucial. Avoiding excessive PEEP and high inspiratory pressures further prevents RV strain and promotes hemodynamic recovery. This case highlights the challenges of managing symptomatic PAPVR and the importance of early recognition. Because of its rarity, PAPVR may be missed until advanced right-sided failure develops. Prompt diagnosis, careful hemodynamic management, and timely surgical referral are essential to prevent deterioration and improve long-term outcomes This abstract is funded by: none