Survival rates have significantly improved following heart-lung transplant.
Shortage in cardiothoracic surgeons may compromise clinical outcomes.
Older patients undergoing surgical procedures, improvements in technique lower mortality rate.
Older transplant patients fare better than younger counterparts.
Gender affects outcomes of bypass surgery; women at higher risk.
A combination of human error and system malfunction was to blame for the widely publicized transplantation failure that led to the recent death of 17-year-old transplant recipient Jésica Santillán. Jésica, who had suffered from cardiomyopathy for several years of her young life, died at Duke University Hospital 2 days after her second heart-lung transplant because the organs that had been deemed to be compatible were not. This was a tragic case in which a death could have been prevented had this incompatibility been detected prior to the operation.
But for every failure, there are many successes in the burgeoning field of transplantation. Let us not lose sight of the fact that, since the first successful heart-lung transplant was performed at Stanford University in 1981, changes in organ preservation management, surgical techniques, and immunosuppressive therapy have significantly improved clinical outcomes following transplant surgery.
Other cardiac surgeries as well, such as coronary artery bypass grafting (CABG), are being performed with increasing safety and success. This is true despite the fact that an increasing number of older patients are undergoing the invasive procedures. In addition to the features associated with improved outcomes following transplantation, the trend toward healthier lifestyles that has been brought about by dietary modifications, exercise regimens, and smoking cessation, are largely responsible for the reduction in mortality rates and enhanced quality of life seen in cardiac surgery patients.
According to a study conducted by Reichart and colleagues at the University Hospital Grosshadern in Munich, Germany, more patients are surviving heart-lung transplants today than when it was a fledgling procedure. These researchers found that among 51 patients who received a heart-lung transplant at their institution between 1983 and 2000, short-term (1-year) survival "markedly improved" and early postoperative deaths dropped significantly after 1994. The 1- to 2-year survival rate at their institution is now greater than 70% among heart-lung transplant recipients.
The researchers attributed these improved statistics to a positive change in the solution used to preserve the donated organs, the development of new immunosuppressive drugs that help prevent short-term organ rejections, and implementation of new surgical methods and drugs that have prevented deaths from bleeding complications.
However, obliterative bronchiolitis (OB), characterized by the development of obstructive changes in the airways, remains the number-one obstacle to better long-term survival rates. There is currently no therapy that can prevent this complication, which developed in half of their patients within 3 years of their transplant surgery, the researchers noted.
A recent report released by the Society of Thoracic Surgeons (STS) warns of a possible shortage of cardiothoracic surgeons in the years to come, predicted on the basis of data from the National Residency Matching Program indicating that fewer new physicians are entering cardiothoracic surgery residency programs and many are slated to retire over the next 10-12 years. The implications of such a shortage, which would lead to delays in care and inferior surgical quality, are made worse by the fact that there will be a concomitant increase in the number of patients requiring heart surgery.
Dramatic increases in malpractice insurance costs in recent years, the long and expensive residency program surgery students must complete (often stretching out to 9 or 10 years), and the sharp reductions made by Medicare in the allowed fees for these procedures are among the reasons for the increasing reluctance to enter this field, according to Dr. Kevin Accola, chair of the STS's Workforce on Health Policy.
We may soon be facing a shortage of cardiothoracic surgeons, but there is heartening news on other fronts that brightens the horizon. Most important, improvements in surgical techniques and expanded efforts to prevent complications in heart disease patients have led to decreased risk of death and morbidity from CABG surgery -- even though the age of patients undergoing this procedure has risen dramatically.
Researchers at Glasgow Royal Infirmary University analyzed approximately 25,000 CABG operations performed in Scottish hospitals between 1981 and 1996. Over the course of the study, the number of operations per year increased more than 7-fold, from 68 to 490 per million population. The investigators found that the percentage of operations conducted in patients older than age 65 increased from 2% to 30% among men over the study period, and from 16% to 45% among women. They found that patients' risk of death decreased over the 15-year study period -- in 1996, there was a 37% reduction in the age-adjusted risk of death among men relative to 1981. The risk reduction was not as significant in women, presumably because they represented a much smaller proportion of the procedures performed.
Another study that supports the notion that heart surgery is getting less risky for older patients was conducted by Rosengart and colleagues. They reviewed the outcomes of 100 patients aged 85-94 years who had undergone elective open-heart surgery such as CABG or valve replacement at New York Presbyterian Hospital-Weill Medical College of Cornell University (New York, NY), between 1994 and 1997. Significant improvements in postoperative death rates were seen compared with outcomes reported 10 years ago for patients in the same age group. After an average follow-up period of 2 years, the researchers found that all 100 patients in their study survived their operations, and about 50% lived at least another 40 months. Among the 45 patients available for follow-up interviews, 71% reported major improvements in functioning, such as reductions in shortness of breath. In addition, the researchers found that the risk of major complications dropped from 24% to 14% over the study period, which they attributed to a greater level of skills among healthcare workers in the use of the bypass pump and anesthesia techniques.
After heart transplantation, too, older patients seem to fare just as well as -- and in some cases even better than -- their younger counterparts. In fact, according to the longest study conducted to date of older people given a donor heart, by Demers and colleagues, older patients (60-70 years of age at time of transplantation; n = 82) were less likely to experience rejection episodes compared with younger patients (aged 18-60 years; n = 403) during the first few months after transplant as well as over the long term. Reporting the findings of their study, the researchers at Stanford University School of Medicine (Stanford, California) noted that 6% of both the younger and older patients had died within 30 days after transplantation; both groups spent an average of 20 days in hospital. The younger group experienced an average of 2.6 episodes of rejection during the first few months after receiving their transplant, compared with an average of 2 rejection episodes during that time period for the older group.
One year later, 39% of older patients still had not shown any signs of rejection, compared with 27% of younger patients. At that time, 83% of the younger group was still alive, compared with 88% of the older group. Five years later, 73% of the younger group was still alive vs 75% of the older group. Ten-year survival rates were almost identical for older and younger patients (50% of the younger group and 51% of the older group were still alive at 10 years). The older group did exhibit poorer outcomes with regard to the development of various types of cancer, however. But they were not more likely than the younger patients to develop lymphomas or infections.
Age appears not to be the only factor affecting outcomes of bypass surgery. Gender may play a role as well. According to a study by Vaccarino and associates, women have as much as a 3 times higher risk of dying during or shortly after CABG than men. The difference in risk is especially pronounced among those under the age of 60, according to lead study author Vaccarino. "The younger the patients, the greater the mortality difference between women and men," she noted.
In this study, the researchers reviewed records of 51,187 patients (29.7% of whom were women) in the National Cardiovascular Network database who underwent bypass surgery at 23 medical centers between October 1993 and December 1999. The women in the study tended to be older -- an average age of 67.5 vs 64.1 for the men. Patients were classified into 5 age groups: < 50 years, 50-59, 60-69, 70-79, and ≥ 80. Before determining the risk of death for each age group, Vaccarino and her colleagues examined the patients' health characteristics, comorbid illnesses, and heart-disease risk factors.
Of note, women tended to have more preexisting illnesses and risk factors for heart disease than men, but they had less-extensive coronary atherosclerosis and better pump function as determined by cardiac catheterization. A smaller percentage of women had suffered a heart attack before their bypass operation. Nevertheless, women younger than age 50 years were more than twice as likely to die as men in the same age group, and women aged 50-59 years had an 86% higher risk of in-hospital death compared with men. Comorbidities and heart-disease risk factors accounted for less than 30% of the mortality differences between young men and women, according to the investigators.
Overall, 5.3% of the women died in the hospital compared with 2.9% of the men. The mortality differences between the sexes declined with older age. Among bypass patients aged 80 years or older, the risk of death was only slightly greater for women (9%) than for men (8.3%).
Heart surgeons perform about 571,000 CABG procedures per year; of those, about 182,000 are performed in women. Further study is needed to determine why mortality rates differ between men and women, said Vaccarino and colleagues, but they speculated that women may have some unidentified risk factor -- which could also explain why women who suffer heart attacks, especially women younger than 60 years of age, have a higher in-hospital death rate than men -- or there may be something in the surgical bypass procedure itself that accounts for the gender-based difference in risk.
Although coronary artery bypass grafting and heart transplantation have saved hundreds of thousands of lives and enhanced the quality of life for many patients with heart disease, there is still much to accomplish in this evolving field. We must be prepared to face the forecasted shortage of cardiothoracic surgeons and the challenges associated with our ever increasingly aging population.
Watch the Cardiology home page in the coming weeks for Part II of this series, which will focus on recent studies examining memory deficits related to cardiac surgery and pharmacologic therapies that may help to improve clinical outcomes.