An Unusual Cause of Dyspnea Diagnosed Late in Life

Abstract

A 67-year-old US military veteran was referred to our clinic for evaluation of progressive dyspnea on exertion over the previous 2 years. His medical history was significant for systemic hypertension, obstructive sleep apnea, and the absence of primary lung disease, significant tobacco use, or coronary artery disease. At the time of consultation, his peripheral blood oxygenation saturation was 85%, hepatojugular reflux and lower-extremity edema were noted, and 6-minute walk distance was 34 m.Transthoracic echocardiography demonstrated normal left ventricular systolic structure and function, a severely dilated right ventricle, and a tricuspid regurgitant jet velocity of 4.85 m/s, indicating an estimated pulmonary artery systolic pressure of 94 mm Hg. However, an elevated flow velocity of 65 cm/s was detected by Doppler interrogation of the posterior aspect of the right atrium adjacent to the interatrial septum. To investigate this further, transesophageal echocardiography was performed, which demonstrated a 1.2-cm communication between the right upper pulmonary vein and the superior vena cava ( Figure 1A) and a respirophasic bidirectional shunt through this lesion ( Figure 1B and Video I in the online-only Data Supplement). Threedimensional echocardiography (Figure 2A and Video II in the online-only Data Supplement) and multislice 3-dimensional reconstructive computed tomographic angiography ( Figure 2B) characterized the defect further and confirmed a normal anatomic origin and insertion of the right upper pulmonary vein at the right upper lobe of the lung and left atrium, respectively.Partial anomalous pulmonary venous connection (PAPVC) describes a rare congenital disease present in up to 0.7% of the general population and is characterized most often by the terminal insertion of a pulmonary vein into the right atrium or superior vena cava in conjunction with a sinus venosus atrial septal defect.1 The present case illustrates an isolated anomalous pulmonary vein without an associated atrial septal defect. This anomaly is believed to result from failure of the splanchnic plexus-derived pulmonary vasculature to separate completely from the right common cardinal vein, which is the embryological precursor of the superior vena cava. Thus, the patient's anatomic anomaly is distinct from the conventional sinus venosus atrial septal defect-associated PAPVC because of the unroofing of the common wall between the right upper pulmonary vein and the sinus venosus myocardium, allowing for the superior region of the atrial septum to remain intact.2 Isolated PAPVC has been described previously in the pediatric literature but is an exceedingly uncommon diagnosis in adults. 1 We believe this patient's adulthood presentation is explained, in part, by right-to-left shunt pathophysiology that occurred, ultimately, as a result of severe pulmonary arterial hypertension from PAPVC-dependent increased pulmonary blood flow, chronic systemic hypertension, and obstructive sleep apnea. Surgical closure of the defect with the Warden proce...

Explaining Unexplained Dyspnea

“…Unexplained RA and RV dilatation on TTE should routinely prompt further investigation of an underlying cause, 1 particularly if pulmonary hypertension or intracardiac shunt is suspected, as might have been in this case by virtue of normal LV size and systolic function. 2 A dilated coronary sinus may be observed in patients with a persistent left-sided superior vena cava (SVC), anomalous pulmonary venous return, RA hypertension or pulmonary hypertension, 3 RV dysfunction, unroofed coronary sinus, 4 or a coronary artery fistula. Overall, on the basis of this patient’s advanced age and clinical presentation, the most probable anatomic lesion by which to account for right-sided chamber dilation is a secundum atrial septal defect (ASD), although a sinus venosus defect (SVD), isolated anomalous pulmonary venous return, and even tetralogy of Fallot have been reported infrequently as causes of exertional shortness of breath and heart failure in the seventh decade of life or later.…”

“…Overall, on the basis of this patient’s advanced age and clinical presentation, the most probable anatomic lesion by which to account for right-sided chamber dilation is a secundum atrial septal defect (ASD), although a sinus venosus defect (SVD), isolated anomalous pulmonary venous return, and even tetralogy of Fallot have been reported infrequently as causes of exertional shortness of breath and heart failure in the seventh decade of life or later. 2,5 Overall, further characterizing the patient’s cardiopulmonary hemodynamics, including oxyhemoglobin saturation levels, in each of the right heart compartments via cardiac catheterization is indicated to characterize pulmonary vascular remodeling, pulmonary hypertension, and the possibility of intracardiac shunt.…”