Patients dying while waiting for bypass operation­-many could be saved

A dissertation from the Sahlgrenska Academy at Göteborg University in Sweden shows that 1.3 percent of those waiting for a bypass operation die waiting. Many more patients would survive if high risk cases were given top priority.

Diseases of the coronary artery are the most common cause of death in the world. Surgery of the coronary artery, bypass operations, reduce the risk of death in the majority of patients and has become one of the most common major surgical interventions. In spite of this, the health care systems of many countries, including Sweden, have not been able to keep up with the demand.

Under-capacity entails long waiting lists, necessitates prioritization among patients, and, in the worst cases, leads to patients’ dying while still in line for an operation. In prioritizing, doctors attempt to assess the risks and then to operate on patients with the most pressing needs first. In western Sweden there are 1.6 million people, and some 250 patients are slated for an operation.

The studies that thorax surgeon Helena Resius bases her dissertation on cover 5,864 patients who were accepted for planned bypass operations between January 1995 and June 1999. The mean waiting period for these patients was 82 days.

“The results show that 77 patients died while waiting for surgery, which is 1.3 percent of the total. This figure can be compared with mortality in connection with the operation, which was about 2 percent for the same period. We were also able to identify several independent risk factors among those who died, such as vascular spasms requiring hospital care, concomitant disease of the aortal valve, deteriorated heart function, and the length of the waiting period,” says Helena Rexius.

Another important issue the dissertation addresses is whether the waiting period affects the outcome of the operation. Theoretically a long period of waiting could entail a deterioration of the patients’ general condition and a decline in heart function, and this would affect survival rates during and after the operation.

“However, we found no evidence that the waiting period impacted survival subsequent to bypass surgery. Furthermore, we found that if the waiting period could be reduced to a maximum of one week for all patients, then the estimated mortality rate, from acceptance to two years after the bypass operation, would be cut by 15 percent compared with the current situation. This effect is achieved by a reduction of mortality during the waiting period,” says Helena Rexius.

On the basis of the above findings, a simple point system was constructed with the aim of singling out patients with heightened risk of dying while waiting for surgery. Points are given for vascular spasms requiring hospital care, concomitant disease of the aortal valve, deteriorated heart function, high operation risk, and male gender. The point system was evaluated among more than five thousand patients who were placed on the waiting list for bypass surgery between 1999 and 2003. Of these patients, 43 percent were put in a low-risk group, 38 percent in a medium-risk group, and 15 percent in a high-risk group. Mortality in the high-risk group was five times higher than in the medium-risk group and 25 percent higher than in the low-risk group.

The study shows that it is possible to identify a relatively small group of patients with a greatly increased risk of dying while waiting for their operation and that these patients should be given top priority. The need for improved prioritization is indicated by the fact that 23 percent of the patients in the high-risk group had not been given the highest clinical priority.