Eisenmenger Syndrome (treatment)

Thursday, March 31, 2011

Eisenmenger syndrome is a heart condition in which abnormal left-to-right atrial or ventricular shunt causes pulmonary hypertension, which in turn, causes increased pressures in the right side of the heart and reversal of the shunt into a right-to-left shunt. Atrial and ventricular shunts are caused by atrial septal defects and ventricular septal defects respectively. Eisenmenger syndrome includes a collection of symptoms, such as cyanosis, which is pale blue or grayish skin due to decreased oxygen in the blood, pulmonary hypertension (high blood pressure in the blood vessels of the lungs), and erythrocytosis, which is increased number of red blood cells in the blood due to decreased oxygen in the blood, and clubbing of fingers. Eisenmenger syndrome primarily affects adolescents and adults with certain congenital heart defects that were repaired late or that were never repaired. Eisenmenger syndrome, however, can occur in infants or children born with pulmonary hypertension; therefore, symptoms related to cyanosis may occur much earlier in life.

In a normal heart, the two chambers of the heart on the left side, that is to say the left atrium and the left ventricle are totally separated (water-tight) from the right side (right atrium and right ventricle) by a wall fibrous tissue and muscle called septum. If a large anatomic defect exists between the two sides of the heart, blood will flow from the left side to the right side. This results in high blood flow and pressure travelling through the lungs. The increased pressure causes damage to delicate capillaries, which then are replaced with scar tissue. Scar tissue does not contribute to oxygen transfer, therefore decreasing the useful volume of the pulmonary vasculature. The scar tissue also provides less flexibility than normal lung tissue, causing further increases in blood pressure, and the heart must pump harder to continue supplying the lungs, leading to damage of more capillaries.

The reduction in oxygen transfer reduces oxygen saturation in the blood, leading to increased production of red blood cells in an attempt to bring the oxygen saturation up. The excess of red blood cells is called Erythrocytosis. Desperate for enough circulating oxygen, the body begins to dump immature red cells into the blood stream. Immature red cells are not as efficient at carrying oxygen as mature red cells, and they are less flexible, less able to easily squeeze through tiny capillaries in the lungs, and so contribute to death of pulmonary capillary beds. The increase in red blood cells also causes hyperviscosity syndrome.

Treatment

1)Medications that help to decrease pulmonary hypertension may be prescribed; these medications include calcium channel blockers, prostacyclin, and endothelin receptor antagonists, and work to dilate blood vessels which helps to lower the blood pressure in the lungs; if right heart failure develops, diuretics (water pills) may be prescribed to help decrease blood volume. 2) Supplemental oxygen may be used during sleep periods or while resting. Use of oxygen may progress to continuous use for symptom relief. 3) Phlebotomy, which is the removal of blood, should not be done frequently, but may be recommended when erythrocytosis causes hyperviscosity (extreme thickness) of the blood; the volume of the blood removed is replaced with intravenous (IV) saline solution to thin the blood; phlebotomy is generally done only when symptoms are severe and/or the hematocrit (the percentage of blood that is made up of red blood cells) becomes extremely elevated. 4) Other treatments: Eisenmenger syndrome that develops as a result of a congenital heart defect that was never repaired is generally not treated by repairing the original defect, as it would increase the workload on the right ventricle and lead to a poor outcome; lung transplantation or heart-lung transplantation may be performed considered when other treatments are no longer effective.