Complications That Arise From the PDA Not Closing

The ductus arteriosus is a blood vessel in developing infants that connects the two main vessels carrying blood out of the heart. The first main vessel takes blood from the heart to the lungs. The second vessel transports blood from the heart to the rest of the body. Imagine an infant developing underwater within the mother's womb. The lungs are collapsed since breathing is impossible. Blood cannot flow through the collapsed lungs, but the ductus arteriosus provides a shortcut. The used blood returning from the infant's body can now bypass the lungs and travel directly out of the heart again. The newborn takes its first breath, the lungs open, and the ductus arteriosus is no longer necessary. In fact, it is now a liability and must close. If it does not, it is called a patent ductus arteriosus (PDA).

Endocarditis

• Bacteria can settle on the patent ductus arteriosus causing a severe infection.

  Endocarditis is an infection of the heart's surface. Leaving a patent ductus arteriosus invites bacteria to settle and multiply within it. Even a very small opening, too small to cause other symptoms, will increase the chances of this devastating infection. In fact, after the child with PDA reaches the age of 20, his chance of getting endocarditis is about 0.5 percent more per year. One third of all deaths from PDA occur because of endocarditis. Closing the PDA either surgically or using a catheter to block the vessel will safely eliminate this risk, which is why many experts recommend closing off even a small PDA.

Effects on the Lungs

• Increased blood flow through the lungs damages the delicate blood vessels.

  A moderate or large sized PDA can cause effects on the lungs that vary in severity from person to person. As blood pressure reaches normal levels in an affected child, blood is pushed backwards through the PDA. It drains from the vessel transporting blood out to the body back into the vessel transporting it to the lungs. It can pass through the lungs two or more times before it finally escapes out to the body. As much as one half to two thirds of the blood may recirculate in this way, causing damage to the delicate blood vessels inside the lungs. This damage is called pulmonary hypertension.

Effects on the Heart

• The overworked heart can fail.

  When the heart is forced to pump recirculated blood, it can pump two or more times the normal amount of blood with each heartbeat. Since the heart can only pump four to six times the normal amount of blood at a maximum, this leaves less room for the heart to increase blood flow during exercise. Fatigue, shortness of breath and palpitations limit exercise in these young people. Finally, the overworked heart becomes enlarged and weakened, putting the young adult at risk for heart failure and fluid buildup in the lungs.

Severe PDA Complications Leading to Death

• Prior to safe effective treatments, PDA would lead to death, often by the age of 60.

  Before safe techniques were available to treat PDA, affected adults would die at a rate of three to four percent per year by the time they reached their thirties. Two thirds of those affected would die by the age of 60. The five percent most severely affected would develop so much damage to the delicate blood vessels of the lungs that blood would no longer travel through the lungs to become oxygenated. Instead it would bypass the lungs, causing feet and toes to turn blue from lack of oxygen.