More than 64 percent of patients who underwent transplantation between 2000 and 2003 survived for at least three years, in comparison to slightly more than 55 percent of individuals operated on between 1988 and 1994.
These statistics appear in a report on the state of organ transplantation in 2005 in the second issue for March 2006 of the American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society.
Marc Estenne, M.D., Ph.D., of the Chest Service at Erasme University Hospital in Brussels, Belgium, noted that 74 heart-lung transplants and 931 bilateral- and 772 single-lung procedures were performed in 2003, according to data from the Registry of the International Society for Heart and Lung Transplantation.
One study found primary grant dysfunction, a severe acute lung injury that occurs in the first 72 hours after transplantation, reduces three-year survival rates. Of the 5,262 patients who were analyzed from an organ sharing network, 10.2 percent were diagnosed with primary graft dysfunction. The 30-day mortality rate for this problem was 42 percent, as compared to 6 percent for those without the complication.
Primary graft dysfunction results from ischemia-reperfusion injury, involving restoration of the flow of blood to the previously highly ischemic organ, which lacks blood and oxygen during transport. Organ transport times are kept to a minimum to assure each organ has the lowest possible cold ischemic time. (Ischemic times are from the point an organ is surgically removed from the donor to the time the organ is transplanted and re-perfused with the blood and oxygen of the recipient.)
"The risk of death persisted beyond the first year, suggesting that the problem has lingering adverse consequences well after resolution of the acute event," said Dr. Estenne.
Another problem that appears to increase mortality rates is the chronic rejection of a transplanted lung or lung allograft, which is defined as a fibrosing process (the formation of abnormal fibrous connective tisue in the airway) that affects the lung. The difficulty is called bronchiolitis obliterans syndrome (BOS).
At the University of Pittsburgh, approximately 30 percent of lung transplant patients develop BOS late in the first year after transplantation. About two-thirds of these patients have an unrelenting loss of pulmonary function that continues for several years.
The report describes several treatments for the syndrome. In one study, 20 patients with BOS were prescribed a low-dose macrolide antibiotic, azithromycin, used for upper and lower respiratory infections. After 3 months, there was a 14 percent increase in pulmonary function for these patients. Improvement was sustained beyond 3 months in 12 of the 17 patients who initially responded.
The same investigators reported positive results from total radiation of the lymph nodes twice weekly for 5 weeks. In 27 BOS patients who completed the treatment, lung function decline in dropped by almost 80 percent.
To determine the optimal procedure for transplant patients with pulmonary fibrosis, one study compared the survival of 636 patients in a national database who underwent single lung transplantation with 185 individuals who received two lungs between 1994 and 2000.
"For patients younger than 60 years, performance of a single lung transplant was associated with superior survival," said Dr. Estenne. "This was attributable to excessive early mortality in the bilateral group, as no survival difference was observed when the analysis was restricted to patients surviving 3 months."
Other investigators reported on the health status of long-term transplant survivors. They found that approximately one-third of the recipients at their center survived 10 years. However, only 18 percent of the long-term survivors were free of BOS: Nearly half had stage 1, 18 percent had stage 2 and 18 percent had stage 3. Survivors also reported a significantly lower quality of life in certain domains, including general health and physical function.
According to a workshop on lung transplantation sponsored by the National Heart, Lung, and Blood Institute, key priorities for the advancement of transplantation include: expansion of the donor pool, accurate prediction of and effective treatment for primary graft dysfunction and BOS and the development of strategies to facilitate induction of immune tolerance.
Contact: Marc Estenne, M.D., Chest Service, Erasme University Hospital, 808 Route de Lennik, B-1070, Brussels, Belgium
Phone: + 00 322 555 39 85/56
E-mail: mestenne@ulb.ac.be
Journal
American Journal of Respiratory and Critical Care Medicine