Gait speed independently predicts both major morbidity and mortality in elderly patients who are about to undergo cardiac surgery, according to a prospective, blinded study.
“This simple, rapid, and inexpensive test effectively stratifies patients beyond traditional estimates of risk, which tend to be inaccurate in the elderly,” said Dr. Jonathan Afilalo of McGill University, Montreal, and his associates.
Half the cardiac surgeries done in North America involve elderly patients (aged at least 70 years), but scoring systems for estimating operative risk perform poorly in this age group, “overestimating mortality by as much as 250%,” they noted (J. Am. Coll. Cardiol. 2010;56:1668-76).
Dr. Afilalo and his colleagues performed what they described as the first study to test the value of gait speed as a predictor of poor outcomes in elderly cardiac surgery patients.
The prospective, blinded study involved 131 patients (mean age, 76 years) who were scheduled to undergo elective coronary artery bypass and/or valve replacement or repair via standard sternotomy at four university-affiliated medical centers across Canada and the United States.
Before surgery, the study subjects were timed as they walked a distance of 5 meters in a well-lit hallway; subjects were permitted to use an aid such as a cane or walker if needed. A time of 6 seconds or longer was classified as a slow gait speed, whereas any time under 6 seconds was classified as a normal gait speed.
The primary composite end point was in-hospital mortality or any of five major complications (stroke, renal failure, prolonged ventilation, deep sternal wound infection, and need for reoperation).
In all, 60 patients (46%) were judged to have slow gait speed before surgery. Interestingly, gait speed did not correlate with the Society of Thoracic Surgeons' risk score, “suggesting that these were representing distinct domains,” the investigators said.
After surgery, 30 patients (23%) experienced the primary composite end point.
Slow gait speed was a strong and independent predictor, associated with a 3.17-fold increase in risk of the primary end point. Moreover, adding gait speed to existing risk prediction models improved their performance in predicting which patients would experience an adverse event and which patients would need “to be discharged to a health care facility for ongoing medical care or rehabilitation,” Dr. Afilalo and his associates noted
Women with slow gait speed appeared to be at particularly high risk for adverse outcomes.
The investigators reported no financial conflicts of interest.
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An Important New Tool
Existing risk-assessment tools for elderly cardiac patients are inadequate, according to Dr. Joseph C. Cleveland Jr. “We must prepare ourselves to face decisions regarding treatment options for this exponentially growing segment of our population with scant data to appropriately guide our decisions.”
In this context, Dr. Afilalo and his associates have given clinicians an important, simple, and “extraordinarily cost-effective” tool, he wrote in an editorial accompanying the study (J. Am. Coll. Cardiol. 2010;56:1677-8). Assessing patients' gait speed requires only an observer, a stopwatch, and a well-lit hallway.
DR. JOSEPH C. CLEVELAND JR., is with the University of Colorado Health Sciences Center, Denver. He reported ties to Thoratec Corp., Heartware Corp, and Baxter BioSurgery.