Aorto-pulmonary Window: Causes, Symptoms & Treatment

Aorto-pulmonary window is a congenital septal defect. The ascending aorta and truncus pulmonalis are connected within the defect, causing pulmonary hypertension, right-sided cardiac strain, and tissue undersupply. Correction of the aorto-pulmonary septal defect is accomplished by surgical separation of the connected vessels.

What is an aorto-pulmonary window?

The ascending aorta corresponds to the initial portion of the aorta that arises from the left ventricle. Cranially, the aortic arch connects to the ascending aorta. The truncus pulmonalis is the trunk of the pulmonary arteries. There is septal separation between this common trunk of the arteriae pulmonales and the ascending aorta in a healthy body. In congenital malformations such as the aorto-pulmonary window, this separation is abolished. The phenomenon is a vascular malformation also known as aorto-pulmonary septal defect. Septal defects are incomplete occlusions of the cardiac septa between the left and right halves of the heart. Blood mixes through the connection between the aorta and the pulmonary artery. The result is flooding, which usually causes damage to the lungs. Depending on the exact location and spread of the vascular defect, physicians distinguish between four different variants of aorto-pulmonary window.

Causes

The cause of aorto-pulmonary window is usually pathohemodynamic changes in the ductus arteriosus apertus. This condition is one of the congenital heart defects. Immediately after birth, physiologically, there may be a connection between the aorta and the truncus pulmonalis, but this closes during the first two days of life. Delay or disruption of this closure occurs primarily in premature infants. Thus, the primary cause of the occlusion disorder is probably oxygen deficiency or possibly elevated prostaglandin levels. Together with an aorto-pulmonary window, there are often manifestations such as an interrupted aortic arch, a ventricular septal defect, an atrial septal defect, a malrotation of the right pulmonary aorta or a tetralogy of Fallot. Less commonly, it results from pathologic changes such as transposition of the great arteries. Pathophysiologically, there is an approximately fivefold increase in pressure in the systemic circulation compared to the pulmonary circulation due to the defective vascular separation. As a result, there is a substantial increase in blood flow to the pulmonary vessels.

Symptoms, complaints, and signs

Patients with aorto-pulmonary septal defect suffer from sequelae such as left-to-right shunt with pulmonary hypertension, right-sided cardiac strain, and insufficient tissue supply. For this reason, pulmonary symptoms such as dyspnea or tachypnea occur. Patients thus breathe excessively fast or suffer from pronounced shortness of breath. In addition, the lower respiratory tract in particular is susceptible to infection, which manifests itself in recurrent infections. Many of the patients are physically weakened, appear fatigued or tire quickly. Often, sufferers sweat faster and more extremely than average. In some cases, sufferers gain insufficient weight, which further exacerbates physical weakness. The persistent left-to-right shunt is associated with a chronic volume load in the right heart. This extra load can result in compensatory eccentric myocardial hypertrophy, in which the tissue of the right heart muscle breaks down. This degradation leads to right heart failure. Pulmonary hypertension is also among a common complication as part of the vascular malformation.

Diagnosis and course

Physicians usually make the diagnosis of aorto-pulmonary fenestration immediately after birth. Affected newborns are clinically notable for marked shortness of breath and fatigability. This clinical picture prompts the physician to order echocardiograms. In addition, radiographic imaging may be performed to visualize increased blood flow through the lung area. The x-ray usually also shows a more or less enlarged heart in patients with aorto-pulmonary window. ECG usually shows no evidence of cardiac abnormalities. Since the aorto-pulmonary window is in many cases only one of several vascular malformations, the cardiovascular system is examined relatively extensively after diagnosis.The earlier the aorto-pulmonary window is diagnosed, the better the prognosis. The corrective results are usually satisfactory. Thus, the long-term prognosis is favorable for patients.

Complications

The aorto-pulmonary window causes cardiac complications and discomfort in most cases. These occur mainly on the right side and may also lead to inadequate tissue supply. In many cases, the patient experiences shortness of breath or dyspnea, which can often lead to panic attacks. Often, the respiratory tract is highly susceptible to infections and other diseases, and the affected person suffers from a general feeling of illness. As a result, everyday life is extremely restricted and performing physical work is usually not possible without further ado. Due to the symptoms of the heart, the patients suffer from cardiac insufficiency and tire relatively quickly. Due to the insufficiency, there is also increased pressure in the lungs. Treatment of the disease is usually by surgical intervention. If this is addressed early, there are usually no further complications or discomfort. In severe cases, lung transplantation may also be necessary. However, this case only occurs when the disease is diagnosed late in adulthood. In this case, death can also occur in the worst case if the transplant is not successful or cannot be performed quickly enough.

When should you go to the doctor?

Aorto-pulmonary window is one of the congenital heart defects that usually become apparent in newborns within the first few days after birth. The aorto-pulmonary window consists of a short circuit between the aorta and the pulmonary circulation, so that the much higher systolic blood pressure peak of the systemic circulation is transmitted to the pulmonary circulation, causing blatant pulmonary hypertension with all the problems that develop. The question of when to go to the doctor can be answered simply, because an untreated aorto-pulmonary window usually has an unfavorable prognosis. Conversely, this means that surgical removal of the short circuit between the systemic and pulmonary circulation as early as possible will result in regression of the emerging secondary damage to the right heart and lungs. In individual cases in which the short circuit is less severe and the congenital heart defect was not noticed, the secondary damage – especially to the lungs – develops very slowly. Cases have been reported in which lung transplantation became necessary in adulthood. When children and adolescents present with symptoms such as shortness of breath, increased respiratory rate, and rapid fatigability, as well as a high susceptibility to respiratory infections, it is recommended that the symptoms be evaluated cardiologically to rule out the presence of a cardiac or vascular malformation that must be treated as expeditiously as possible to prevent irreversible damage.

Treatment and therapy

Patients with aorto-pulmonary septal defect receive a causative treatment approach. Instead of addressing the individual symptoms, the inadequate septal closure and thus the primary cause of the symptoms is corrected. This correction is equivalent to an invasive procedure and thus takes place during surgery. As a rule, a heart-lung machine is used in this operation. This is a medical device that can replace the heart pumping function and function of the lungs for a period of time. During surgery with the heart-lung machine, blood leaves the body through a system of tubes, is oxygenated outside the body, and is then returned to the body. Basically, during the operation, the surgeon separates the vessels and closes them using patches. Depending on the severity of the vascular malformation present, different surgical options are available for this purpose. As long as the operation is performed as soon as possible after the actual diagnosis, excellent results can be achieved in most cases. In rare cases, the heart defect is not diagnosed until adulthood. Because of fixed pulmonary hypertension, curative treatment is not possible in such late diagnosis. In this case, the affected individuals usually receive a lung transplant.

Outlook and prognosis

Vascular malformation of the aorta has a good prognosis if diagnosed early. Because it is diagnosed in most cases during childhood, there is a good chance of a good recovery after treatment. In a surgical procedure, the aorto-pulmonary window is corrected. A permanent relief of the symptoms occurs and the child can be discharged as cured within a short time. In everyday life, the patient often no longer notices any impairments over the next few years. If the malformation is not noticed until adulthood, various complaints or impairments often already exist. Although the vascular malformation can also be completely corrected and healed in adults, the patient suffers from other conditions. These sequelae influence the patient’s recovery immensely, which often leads to the fact that freedom from symptoms is no longer possible. In some patients, organ transplantation is necessary to achieve an improvement in health and well-being. The quality of life normally improves again afterwards. Nevertheless, a complete cure is not given. In addition, the healing process is delayed and can take several years. Often the heart and lungs are weakened. Transplantation of an organ is associated with further complications and challenges that must be overcome.

Prevention

Aorto-pulmonary window cannot be actively prevented. However, the condition is an extremely rare phenomenon anyway, with few case reports or case numbers.

Follow-up

In this disease, the affected person is primarily dependent on a rapid diagnosis with subsequent treatment to prevent further complications or possible cardiac death. If this does not result in treatment, serious complications occur that can significantly complicate the affected person’s daily life. Special aftercare measures are usually not available to the affected person. The earlier the disease is detected, the better the further course of the disease usually is. In general, the person affected by this disease should pay attention to a healthy lifestyle with a healthy diet. Greasy or very sweet foods should be avoided, and sporting activities can also have a positive effect on the course of the disease. However, surgical interventions are usually necessary. After such an operation, the affected person should rest and take care of his body. Exertion or stressful activities are not advisable, so that most patients are dependent on the help and care of relatives. The further course and life expectancy of the affected person depend greatly on the exact manifestation of the symptoms.

What you can do yourself

The special nature of the disease means that preventive measures have no direct influence on the course of the disease. Patients must therefore pay increased attention to their general health. The risk of recurrent respiratory infections is higher than in healthy patients. Here it is important to maintain a balance between overly cautious behavior that avoids real or perceived dangers (infectious environment, cold) and a lightly demanding strain on the body (stimulating climate, lightest sports such as walking in the fresh air). Regular exercise is crucial in the supportive therapy of many diseases. Because the disease often causes respiratory distress, the aortopulmonary window can cause great anxiety and panic in the patient. Anxiety can be countered through targeted respiratory therapy. Meditative exercises, autosuggestion, autogenic training are helpful measures for emergencies when it becomes vital to push back the rising panic. Special breathing exercises are also helpful when there is an increased need for oxygen. Patients diagnosed with aortopulmonary window fatigue rapidly; it is imperative that consideration be given to this in the environment.