PAPVR is a congenital defect (present from birth)(1).
The estimated incidence of PAPVR is around 0.4-0.7% in postmortem series(1).
What Are The Ways To Prevent PAPVR & Does It Reoccur?
PAPVR (Partial Anomalous Pulmonary Venous Return) or PAPVC (Partial Anomalous Pulmonary Venous Connection) is a rare congenital defect of the heart. Congenital means ‘present by birth’. Since PAPVR is present by birth, there is nothing one can do to prevent it from occurring. It has no known cause and possibly is multifactorial in origin that may include a genetic component. It is also associated with other congenital conditions, such as Turner’s syndrome(1).
Normally, the heart is made up of four chambers, namely, right and left atria and right and left ventricles. It is connected through arteries and veins to the lungs and the rest of the body. The heart pumps blood to all parts of the body. The right side of the heart, mainly the atria collects deoxygenated blood from the whole body through superior and inferior vena cava, which in turn reaches the lungs for oxygenation via the main pulmonary artery. Whereas, the left side of the heart, mainly the left atria, collects the oxygenated blood from the lungs via pulmonary veins and pumps the oxygenated blood from the left ventricles to the whole body through aorta(2).
Does PAPVR Reoccur?
The definitive management of PAPVR is the surgical correction of the anomalous connection of the pulmonary vein to the right side of the heart and correction of the associated atrial septal defect. After the defect is corrected, PAPVR does not recur. However, if PAPVR is not detected at the right time and is detected late in adulthood when the patient is not surgically fit, the complications associated with right-sided heart failure and pulmonary hypertension progress, which makes the prognosis guarded and patients need medications to manage the complications.
However, overall, the prognosis of PAPVR is excellent with a perioperative mortality rate of <0.1%(1).
What Is PAPVR?
PAPVR is a congenital abnormality of the heart in which one or few pulmonary veins are anomalous and instead of draining oxygenated blood to the left atrium, they drain the oxygenated blood to the right atrium creating a left to right shunt. Thus, oxygenated blood mixes with the deoxygenated blood and circulates back to the lungs without circulating to other organs of the body. This has no immediate consequence since only a single pulmonary vein is abnormal. This is in direct contrast to TAPVR (Total Anomalous Pulmonary Venous Return) in which all or most of the pulmonary veins connect to the right side of the heart making TAPVR more fatal(1).
PAPVR involving the right lung vein is twice more common than the PAPVR involving the left lung. PAPVR associated with the right upper pulmonary vein connecting to the right atrium or the superior vena cava is the most common form of PAPVR. In this form, atrial septal defect (ASD) of sinus venosus type is mostly found. The right pulmonary vein can also drain into the inferior vena cava; whereas, the left pulmonary veins mainly drain into an innominate vein, coronary sinus, and rarely into the right atrium, cavae, or left subclavian vein(1).
Clinical Presentation Of PAPVR
Initially, PAPVR is asymptomatic and may remain asymptomatic throughout life depending on the number of the anomalous pulmonary vein.
There is a consensus of some authors that PAPVR is clinically significant if ≥50% of the pulmonary veins have abnormal blood return. In 80-90% of the cases, PAPVR is associated with atrial septal defect (ASD) that might add to the complication. In the long run, the continuous pulmonary venous return to the right side of the heart leads to right atrial and ventricular dilation, which causes the risk of arrhythmia, right-sided heart failure, and pulmonary hypertension(1).
Patients may present with the symptoms of shortness of breath, chest pain, exercise intolerance (mainly in children), palpitations, peripheral edema, hemoptysis, and other complications of right-sided heart failure and pulmonary vascular obstructive disease(1).