Partial Anomalous Pulmonary Venous Return - Overview

What Is Partial Anomalous Pulmonary Venous Return?

A very uncommon type of congenital heart disease is the partial anomalous pulmonary venous return (PAPVR). The amount of blood carrying oxygen from the lungs to the heart is affected. All newly oxygenated blood is typically returned to the left side of the heart by pulmonary veins. However, with PAPVR, they transport a portion of the blood to the right side, which is only supposed to store blood with low oxygen levels.

How Does This Condition Occur?

Partial anomalous pulmonary venous return (PAPVR) results in a non-traditional direction of blood flow across the heart, causing a left-to-right cardiac shunt. The term "partial anomalous" refers to a condition in which a portion, rather than the entirety, of oxygenated blood from the lungs, fails to follow the typical route back to the heart.

• This phenomenon occurs due to the presence of one or more pulmonary veins that transport oxygenated blood to the right atrium instead of the left atrium.

• The right atrium of the heart consists of a combination of deoxygenated and oxygenated blood.

• The right ventricle is obligated to eject this oxygen-depleted blood into the pulmonary circulation.

This implies the occurrence of two simultaneous events that are deemed inappropriate.

• Initially, a portion of oxygen-rich blood is redirected toward the lungs despite its recent departure from the same organ.

• Furthermore, the heart's right ventricle experiences an increased volume of blood that necessitates its propulsion toward the lungs.

• The additional workload may have an impact on the cardiovascular system.

What Are the Signs and Symptoms?

In pediatric patients, the clinical signs comprise the following:

• Growth retardation (happens when the development of the fetus is slower or faster than usual).

• Experiencing fatigue during physical activity.

• Recurrent respiratory infections refer to a condition characterized by repeated occurrences of infections affecting the respiratory system.

• Dyspnea (a feeling of running out of air and unable to breathe thoroughly or quickly enough).

• Difficulty in achieving weight gain.

Adults with partial anomalous pulmonary venous return (PAPVR) may exhibit symptoms such as:

• Dyspnea (a feeling similar to that of running out of oxygen and not being able to breathe quickly enough or deeply enough to compensate for it).

• Fatigue.

• Cardiac palpitations(feelings or sensations of a pounding or racing pulse).

• The individual is experiencing discomfort or pain in the chest region.

• Tachycardia (a heart rate exceeding 100 beats per minute. Various forms of irregular heart rhythms have the potential to result in tachycardia).

• Recurrent respiratory infections refer to repeated infections affecting the respiratory system.

What Are the Causes?

Pulmonary anomalous venous return (PAPVR), like other congenital cardiac anomalies, results from abnormal fetal cardiac development in the uterine. A joint pulmonary vein typically gives rise to four pulmonary veins during the early phases of gestation. These blood vessels form a link with the embryonic left atrium. However, alterations to this physiological mechanism lead to the connection in the pulmonary veins for the right atrium or adjacent veins.

What Are the Diagnostic Methods?

PAPVR may co-occur with other cardiac anomalies and can potentially be identified shortly after delivery. In cases where the severity of the condition is low, it is possible that a diagnosis may not be made until the individual reaches adulthood.

• Physical Examination- A healthcare professional conducts a physical examination and auscultates (investigates a patient by hearing sounds from the heart.) An auditory manifestation, commonly referred to as a heart murmur, characterized by a whooshing sound, may be detected.

• Echocardiogram- Partial anomalous pulmonary venous return can be diagnosed through the use of an echocardiogram. The imaging modality employed in this examination involves the utilization of acoustic waves to generate visual representations of the cardiac muscle's rhythmic contractions. The echocardiogram modality can visualize the pulmonary veins and assess the dimensions of the cardiac chambers. Additionally, it quantifies the velocity of blood circulation. Echocardiography can aid in diagnosing an atrial or ventricular septal defect, commonly known as a hole in the heart.

Additional diagnostic procedures, such as electrocardiography (ECG or EKG), chest radiography, or computed tomography (CT) imaging, may be conducted to obtain further data.

• Simple Radiograph - Chest radiographic characteristics vary by subtype of PAPVR. Rarely is the abnormal vein identified, except in instances of Scimitar syndrome(it is an unusual form of congenital heart abnormality that can affect infants. Babies who are born with scimitar syndrome have a right lung and pulmonary artery that are not fully developed at birth.) If venous drainage is obstructed, pulmonary venous congestion will be observed.

• CT - Using contrast-enhanced investigations with MDCT technology permits detecting and characterizing anomalies. It is regarded as the preferred imaging modality.

What Is the Treatment Method?

• In Pediatric Patients - Surgical intervention is typically employed to address PAPVR in pediatric patients, particularly if the condition is sufficient to result in a notable shunt. Patients who are being considered for surgical repair are at a higher risk of developing pulmonary hypertension and right ventricular failure.

• Among Adult Patients - Individuals who exhibit symptoms resulting from shunting or present with indications of right-sided volume overload, irrespective of the shunt's magnitude, are also evaluated for surgical intervention. Nonetheless, in individuals who exhibit no symptoms, possess a low shunt fraction, and lack clinical or echocardiographic indications of right heart stress, pulmonary hypertension, or other symptoms, surgical intervention may not be required.

1. Surgical Procedures -The fundamental principle underlying surgical repair involves segregating the pulmonary venous system through the systemic system. The procedure entails connecting the anomalous pulmonary vein(s) to either the left atrium or, more frequently, to the right atrial appendage through anastomosis.

For individuals diagnosed with severe pulmonary arterial hypertension (PAH) and heightened pulmonary vascular resistance, restorative surgery is improbable to modify the progression of the disease due to the extensive vascular restructuring being unlikely to be reversible. For individuals with similar medical conditions, such as the patient described in the second case, heart-lung transplantation may represent the sole viable curative alternative.

2. Catheter Embolization - In certain cases, catheter embolization of anomalous veins may be a viable option for patients, contingent upon the presence of a connection between the anomalous vein and the LA(left atrium) that can facilitate venous drainage after the embolization of the anomalous vein.

Conclusion

PAPVR is a rare congenital defect that frequently appears asymptomatically and can have uncommon clinical characteristics in adults. The immediate detection and care of symptoms is critical in preventing symptoms from progressing and the onset of severe pulmonary arterial hypertension. When examining unusual etiologies in patients with chronic cough, computed tomography (CT) of the chest might be better than plain radiography. In cases when individuals develop symptoms, immediate surgical repair is the optimum way of treatment. In severe cases of pulmonary hypertension, it may be appropriate to consider earlier measures, such as potent pulmonary vasodilator therapy with bosentan.