SAN FRANCISCO, April 23, 1999 — The number of patients with cystic fibrosis (CF) who die waiting for lung transplants will likely increase if surgeons are required to follow new international wait-listing guidelines and current geographic disparities in waiting times persist, a surgeon from the University of Pittsburgh Medical Center (UPMC) reported today at the International Society for Heart and Lung Transplantation’s 19th annual meeting in San Francisco.
Robert J. Keenan, M.D., who heads the lung transplant program at the UPMC, said the results of his study, which examined outcomes of 164 CF patients evaluated for transplantation, indicate that the medical criteria adopted last year by the transplant community are too restrictive. As such, in the United States, where organs are allocated in a local-first system, this would limit the window of opportunity that donor organs can be found.
"At our center, and at other centers in the United States that tend to have longer waiting times, we expect there to be substantial mortality on the waiting list. If geographic disparities in waiting times were minimized, these guidelines might be more reasonable for medical practice," said Dr. Keenan, associate professor of surgery in the division of cardiothoracic surgery.
More than 25 percent of all patients needing lungs die waiting, according to figures from the United Network for Organ Sharing (UNOS), and these rates vary from region to region. Patients with CF account for more than a third of all those needing double lungs and about 15 percent of those needing hearts and lungs. CF is the most common fatal genetic disease among the Caucasian race.
"Based on our results, two things must happen. First, we need to take a closer look at the outcomes of CF patients at other centers and re-evaluate the merits of the current guidelines. Secondly, we need to be assured that CF patients, like others on the list, are not forced to wait beyond a period that they can be expected to survive. There is no way to justify waiting times that vary from four weeks to three years, as has been recently reported," said Dr. Keenan.
The guidelines adopted last year have been incorporated into national policy by UNOS and are used by insurance companies to judge whether the costs of evaluation or transplantation will be covered. The guidelines seek to assess a patient’s progression of CF by measuring the volume of air that can be expired and the percentage of oxygen and carbon dioxide in their arterial blood. Specific values of these tests are included in the guidelines.
Dr. Keenan and his team conducted a retrospective study to determine if these guidelines were indicative of survival, both on the waiting list and after transplantation. Of the 164 patients with CF seen at the UPMC between 1990 and 1998, 159 were accepted for transplantation and placed on the list; 70 received transplants, 58 at the UPMC; 53 died on the waiting list; and 36 remain on the list.
The average amount of time patients waited until transplantation was 590 days, yet the average time that a patient was on the list before dying was 399 days.
"Among the most significant predictors of death on the waiting list was the percentage of carbon dioxide in the blood, but these were at lower percentages than stipulated in the guidelines," reported Dr. Keenan.
Other significant predictors included the presence of certain infection-causing organisms and the inability of patients to walk 800 feet within six minutes. These parameters, Dr. Keenan noted, are not even included in the guidelines. The test to determine expiration volume, which is included, was not predictive at all, the results reveal.
Further analysis of the 58 patients who received transplants at the UPMC found not one of the criteria in the international guidelines to be predictive of survival after transplantation.
About 3,200 patients are on the national waiting list for single or double lung transplants. Because of the nature of the disease, those with CF benefit most from double lung transplants. CF affects about 30,000 children and young adults, but one in 28 Caucasians are symptomless carriers of the gene. The symptoms include persistent wheezing and coughing and susceptibility to pneumonia as excessive mucus clogs the lungs. CF is characterized by the inability of epithelial cells, those that line the lungs and digestive organs, to secrete sodium and chloride.