Refers to the process in which a long-standing left-to-right cardiac shunt caused by a congenital heart defect causes pulmonary hypertension, and eventual reversal of the shunt into a cyanotic right-to-left shunt.
It is typically caused by a ventricular septal defect, atrial septal defect, or less commonly, patent ductus arteriosus.
With the use of fetal screening echocardiography early in life, its incidence has decreased.
In a pregnancy it can cause serious complications, including mortality that ranges from 30% to 60%.
Pregnancy associated Eisenmenger’s syndrome and may be related to fainting spells, venous embolization, hypovolemia, coughing up blood and preeclampsia.
Most deaths in pregnancy from Eisenmenger’s syndrome occur either during or within the first weeks after delivery.
Pregnant patients with Eisenmenger syndrome should be hospitalized after the 20th week of pregnancy, or earlier if clinical deterioration occurs
Findings with Eisenmenger syndrome include.:
High red blood cell count
Clubbing of the digits.
Abnormal heart rhythms
A low index or percentage of cardiac output ejected through a shunt is harmless.
A high index or percentage of cardiac output ejected through a left-to-right shunt heralds Eisenmenger’s syndrome.
Increased right-sided blood volume and pressure causes damage to the pulmonary capillaries, causing them to be replaced with scar tissue.
Scar tissue does not contribute to oxygen transfer, therefore decreasing the useful volume of the pulmonary vasculature.
The scar tissue is less flexible and the decreased compliance of the lung tissue, caused further increases in pulmonary blood pressure, and the weakened heart must pump harder.
The damage is considered irreversible, even if the underlying heart defect is corrected.
The increased resistance and decreased compliance of the pulmonary vessels, elevated pulmonary pressures causes the right heart to hypertrophy.
When right ventricular hypertrophy causes right heart pressures to exceed that of the left heart, the Eisenmenger’s syndrome begins.
Increased right ventricular heart pressures lead to reversal of blood flow through the shunt, as blood moves from the right side of the heart to the left side.
As a consequence, deoxygenated blood returning from the body bypasses the lungs through the reversed shunt and proceeds directly to systemic circulation, leading to cyanosis and resultant organ damage.
A right-to-left shunt, causes reduced oxygen saturation in the arterial blood due to mixing of oxygenated blood returning from the lungs with the deoxygenated blood returning from systemic circulation.
This decreased oxygen saturation sensed by the kidneys, results in a compensatory increase in erythropoietin production and an increased production of red blood cells.
The increased systemic reticulocyte count, risks a hyperviscosity syndrome as reticulocytes are less efficient at carrying oxygen as mature red cells, and they are less deformable, causing impaired transit through capillary beds.
This hyperviscosity contributes to the death of pulmonary capillary beds.
With Eisenmenger’s syndrome there is the possibility of both uncontrolled bleeding due to damaged capillaries and high pressure, as well as spontaneous clots due to hyperviscosity and stasis of blood.
Management: If the defect in the heart is identified before it causes significant pulmonary hypertension, it can normally be repaired through surgery, preventing the disease.
After pulmonary hypertension is sufficient to reverse the blood flow through the defect, the maladaptation is considered irreversible, and a heart–lung transplant or a lung transplant with repair of the heart is the only curative option.
If catheterization assessment of the pulmonary artery pressure indicates its two thirds of systemic pressure that will preclude repair of the defects.
Transplantation is only for patients with poor prognosis and quality of life.
5-year and 10-year transplantation survival ranges between 70% and 80%, 50% and 70%, 30% and 50%, respectively.
The average life expectancy of patients after lung transplantation is as low as 30% at 5 years, patients with reasonable functional status related to Eisenmenger syndrome have improved survival with conservative medical care compared with transplantation.
Air filters for intravenous lines are recommended for persons with Eisenmenger’s syndrome to reduce the risk of accidental introduction of air into the veins due to the increased risk for paradoxical air embolism.