Indications
In a normal heart, oxygen-depleted blood ("blue") is pumped from the right side of the heart, through the pulmonary artery, to the lungs where it is oxygenated. This is the pulmonary circulation part of blood flow. The oxygen-rich ("red") blood then returns to the left heart, via the pulmonary veins, and is pumped through the aorta to the rest of the body, including the heart muscle itself. This is the systemic circulation part of blood flow, the other loop of an interconnected normal cardio-pulmonary system.
With d-TGA, certain major blood vessels are connected improperly, so oxygen-poor blood from the right heart is pumped immediately through the aorta and circulated to the body and the heart itself, bypassing the lungs altogether, while the left heart pumps oxygen-rich blood continuously back into the lungs through the pulmonary artery. This is a life-threatening situation due to the resultant low oxygen levels throughout the body. Atrial septostomy allows more of the oxygen-rich blood to circulate throughout the body. The procedure is a temporary measure meant to help the patient survive until further corrective surgery can be done.
In the separate case of pulmonary hypertension, abnormally high blood pressure in the blood vessels within and connected to the lungs puts stress on the right side of the heart, potentially leading to right heart failure. Atrial septostomy relieves some of this pressure, but at the cost of lower oxygen levels in the blood (hypoxia). As with d-TGA, this surgery is not a definitive solution to the underlying medical problem.
Read more about this topic: Atrial Septostomy
Famous quotes containing the word indications:
“It is difficult to write a paradiso when all the superficial indications are that you ought to write an apocalypse. It is obviously much easier to find inhabitants for an inferno or even a purgatorio.”
—Ezra Pound (1885–1972)
“The indications are that swearing preceded the development of cursing. That is, expletives, maledictions, exclamations, and imprecations of the immediately explosive or vituperative kind preceded the speechmaking and later rituals involved in the deliberate apportioning of the fate of an enemy. Swearing of the former variety is from the lips only, but the latter is from the heart. Damn it! is not that same as Damn you!”
—Ashley Montagu (b. 1905)
“You must labour to acquire that great and uncommon talent of hating with good breeding, and loving with prudence; to make no quarrel irreconcilable by silly and unnecessary indications of anger; and no friendship dangerous, in care it breaks, by a wanton, indiscreet, and unreserved confidence.”
—Philip Dormer Stanhope, 4th Earl Chesterfield (1694–1773)