How Fast (or Slow) Someone Walks Helps Predict Cardiac Surgery Outcomes
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Simple Gait Speed Test Gauges Frailty and Identifies Hidden Factors that May Increase Risk of Post-Surgical Problems among an Increasing Pool of Elderly Patients with Heart Disease
Elderly patients who walk slowly—as determined by a simple gait speed test—have a three-fold greater risk of experiencing a major complication or death following cardiac surgery than those who walk at a normal pace. Slow gait speed—an objective and validated marker of frailty—also appears to double one’s likelihood of being discharged to another health care facility or having a prolonged post-surgical hospital stay, according to a new study published in the November 9, 2010, issue of the Journal of the American College of Cardiology. Based on the findings, adding gait speed to existing cardiac surgery risk models appears to improve the predictive value of these models, helping clinicians identify vulnerable patients who might have been missed by using conventional measures such as ejection fraction alone.
This multicenter study is the first to test the value of gait speed—the time it takes a person to walk 5 meters at a comfortable pace—as a predictor of postoperative death or major complications in elderly cardiac surgery patients.
“There is no reliable eyeball test to identify frailty or whether someone is fit to undergo cardiac surgery or not. An elderly patient may look good in a resting state in a hospital bed, but this can be misleading,” said Jonathan Afilalo, M.D., MSc, Division of Cardiology, SMBD-Jewish General Hospital, McGill University, Montreal, QC, Canada, and lead author of the study. “Our study shows that the gait speed test—sometimes referred to as a geriatric vital sign—can help clinicians identify vulnerable patients. It’s a tool that can be applied in daily practice with minimal investment.”
Frailty has been shown to lower one’s resiliency to stressors and cardiac surgery certainly presents a major stressor. Accounting for frailty also allows for more comprehensive risk stratification. However, Dr. Afilalo cautions that walking speed should not be used in and of itself to determine whether patients should or should not undergo coronary artery bypass and/or valve replacement or repair.
“Many elderly patients need heart surgery, which may improve their quality of life, alleviate symptoms and prevent potentially life-threatening cardiac events,” he said. “These findings should compel us to look at ways to provide better care to these patients before, during and after surgery and to investigate whether comprehensive geriatric assessments, intensive monitoring, early mobilization and/or structured exercise training programs may prove beneficial.”
Of the 131 patients included in the study (mean age of 75.8 +/- 4.4 years), 60 (46%) had slow gait speed—defined as taking more than 6 seconds to walk five meters. Treating physicians were blinded to the gait speed test results so as not to influence their decision to proceed with surgery or determine postoperative management.
Slow walkers had an unfavorable profile overall, facing higher death rates, taking a longer time to recover and be discharged from hospital, and requiring more rehabilitation facilities. Interestingly, elderly women – especially those with diabetes – were more likely to be slow walkers. In fact, elderly women with a slow gait speed had an 8-fold increase in morbidity and mortality.
“Future studies need to further explore these gender differences and investigate targeted interventions for elderly patients with slow gait speed,” said Dr. Afilalo. “It often wasn’t the thin elderly lady who was most likely to be frail as most might have guessed, but the heavier one, casting even more doubt on the eyeball test for frailty.”
Elderly patients account for half of the cardiac surgeries performed in North America and as many as 78 percent of the major complications and deaths. To date, most risk assessment tools are used to predict death, not complications, which are a major driver of costs and reduced quality of life. Based on this study, adding gait speed to existing cardiac surgery risk models appears to improve the predictive value of these models.
In his accompanying editorial, Joseph C. Cleveland, JR, M.D., University of Colorado Health Sciences Center, Denver, Colorado, states that Dr. Afilalo and his team “have given clinicians an important tool to help us care for the exponentially expanding pool of elderly patients with heart disease…This new screening tool – consisting of an observer, a stopwatch and a well lit hallway, is reproducible and, I believe will be extraordinarily cost-effective.”
Dr. Afilalo reports no conflicts of interest.
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