Frail Elderly and Cardiac Surgery
Abstract & Commentary
By Michael H. Crawford, MD
Source: Lee DH, et al. Frail patients are at increased risk for mortality and prolonged institutional care after cardiac surgery. Circulation. 2010;121:973-978.
Although age is a risk factor for morbidity and mortality with cardiac surgery, chronologic age does not always reflect biological age. Although frailty has been shown to predict falls, hospitalization, institutionalization, and mortality in geriatric populations in the community, it has not been systematically studied in patients undergoing surgery. Thus, these investigators from Canada identified 157 frail patients undergoing cardiac surgery. Frailty was defined as having one of the following three characteristics: lack of independence in activities of daily living (64 patients), impaired ambulation (124), and dementia (22). The frail patients represented 4% of those undergoing cardiac surgery. On average, frail patients were older than non-frail patients, although the age ranges were similar (71 years, 61-78 vs. 66 years, 57-74 years). Frail patients were more likely to be female and have more comorbidities, which increases the risk of surgery. Logistic regression analysis showed that frailty was an independent predictor of in-hospital and two-year mortality (OR = 1.8 and 1.5) and discharge to an institution (OR = 6.3). The authors concluded that an assessment of frailty improves preoperative risk assessment in cardiac surgery and should be considered in decisions regarding processes of care.
As the U.S. population becomes increasingly older, frailty has emerged as a condition that impacts prognosis in general surgery and other procedures, but this is the first report of its impact on cardiac-surgery outcomes. There is no accepted definition of frailty, but most clinicians would liken it to art"I know it when I see it." These investigators described it as a biologically reduced resistance to stress that is characterized by decreased activity, poor endurance, and the need for help in activities of daily living (dependence). They included dementia as a criterion because of other data showing that it impacts outcomes and leads to reduced activity and dependence.
They set a low bar for frailty, requiring only one of three factors: impaired ambulation, dependence, and dementia. Yet, they showed that frailty, by this definition, independently predicted mortality and discharge to an institution rather than home. Interestingly, the majority of patients classified as frail met the criterion of impaired ambulation, which is not infrequent. Although frail patients were older on average, the influence of frailty was independent of age. Several factors are independent predictors of mortality post-cardiac surgery, but only three had higher odds ratios than frailty (OR = 1.8): urgent surgery (OR = 5.1), renal failure (OR = 2.3), and congestive heart failure (OR = 2.2). In the prediction of need for institutionalization, frailty had the highest OR (6.3), followed by urgent surgery (4.5). Other factors had ORs of 2.0 or less.
These findings have implications for the management of patients being considered for cardiac surgery. The consent process should include this additional risk, since it is not accounted for in the STS or Euroscore risk models that are often used. Also, frail patients should be strongly considered for other management strategies rather than traditional cardiac surgery.