January 19, 2000
UW surgeon performs region’s first surgery to clear lung arteries
The first surgery of its kind in the region, performed at University of Washington Medical Center, has given a once very ill 48-year-old Alaska man, who faced a lung transplant and/or potentially heart failure, a normal life expectancy and the hope of living a normal life.
Fewer than a half-dozen surgeons worldwide perform the operation, which involves putting the patient in a sort of suspended animation.
The surgery involves removing obstructions to blood flow within the lung bed: 18 segmental branches of artery that themselves branch into two or three subsegments each. The removal of the obstructing plaque and clots must be completed in an hour or less. That’s because the patient has to be chilled to about 64 degrees Fahrenheit and placed on a bypass machine. The heart and circulation are stopped in order to perform the surgery.
Dr. Michael Mulligan, an assistant professor of cardiothoracic surgery, performed the pulmonary thromboendarterectomy (PTE). UW Medical Center becomes the third place in the nation to regularly offer this surgery.
“It’s technically a very demanding procedure, but the results are excellent and very satisfying. Many of these people come in on oxygen, and they’re so breathless that they can barely walk from the kitchen to the bathroom. After the operation, most can go on to live essentially normal lives,” Mulligan says.
People eligible for PTE suffer from a condition that may be hard to recognize and diagnose. That’s because its symptoms ? such as shortness of breath, chest pain, fatigue, leg swelling and lightheadedness ?mimic other, more common conditions. What’s happened is that the person has had a lung clot that, even if it has dissolved, has created rubbery scar tissue. This tissue attracts calcium plaque deposits throughout the lung bed, sometimes far away from the original clot. The presence of all that obstruction causes their right heart pressure to climb.
The technical term for this condition is pulmonary hypertension from chronic pulmonary emboli (PE). Patients may not be diagnosed until they have the most advanced symptom of the condition: right heart failure. Before the pulmonary thromboendarterectomy, the only treatment available was a lung transplant.
It’s estimated that about 600,000 people in the United States develop pulmonary emboli annually. A small percentage will develop the spreading plaque.
Doctors have learned through experience with PTE that it’s not enough to clean out the main arterial branches in the lung; the surgeon must also clean plaque from the sub-branches that snake around the periphery of the lung.
“You can’t simply suction that material out. It’s densely adherent. It has to be carefully surgically dissected free, and removed,” Mulligan says.
Mulligan uses a special instrument about 18 inches long, which ends in a tip about 2 millimeters wide. It has a little basket, like a scoop, that allows the surgeon to free the plaque from the artery wall, while a small suction tube clears out any blood that obscures the surgeon’s vision, as it snakes up and down arterial walls.
In order to control the profuse flow of blood that normally courses through the lungs, the patient must be cooled during the operation so that blood flow can temporarily be slowed.
Mulligan explains that the person survives this procedure for the same reasons as someone falling into an iced-over lake: the cold temperature slows metabolism to the point where the rate of oxygen use is greatly reduced, and the person does not need a lot of blood flow to vital organs. That’s critical, since blood flow to the brain is greatly reduced during the operation.
People whose lung bed has been cleared can eventually resume normal activities. “It’s not like one of those diseases where you treat it, but the person has already been so destroyed by the disease that it’s taken years off their life,” Mulligan says. “These people can go on to enjoy normal life expectancies. Many of them have trouble embracing this. They’ve been so ill that they are used to wondering day-to-day if they will survive at all.”
