Age as risk factor for stroke in CABG patients challenged
MedWire News: Avoiding coronary artery bypass grafting (CABG) in elderly patients on the basis of high perioperative stroke risk is "debatable," say researchers who found that age per se does not predict stroke in these patients.
Rather, patients' risk for stroke was linked to their presumed atherosclerotic burden, represented by comorbidities such as previous stroke, diabetes, and peripheral vascular disease, the team reports in the journal Stroke.
Charlotte Mérie (Copenhagen University Hospital, Denmark) and colleagues studied data from the Danish National Hospital Register for 25,159 patients who underwent CABG from 1997 through 2006. In Denmark, it is normal practice to select patients for cardiac surgery according to their EuroSCORE, which assesses patients' risk for perioperative mortality based on various patient, cardiac, and operative factors, explains the team. Patients at very high risk would likely not have been operated on.
Overall, 2.0% of patients had a perioperative stroke (within 30 days of surgery) and the rate rose with increasing age, from 10.1 per 100 person-years for those younger than 60 years to 38.1 per 100 person-years for those aged 80 years or older.
When the researchers adjusted their findings for gender, comorbidities, and medication use, age remained related to stroke risk only among younger patients, with stroke being 1.7-fold more likely to occur among patients aged 60-64 years and 2.4-fold more likely among those aged 65-69 years, relative to those younger than 60 years.
But the risk leveled off among older patients, with 2.8-, 2.8-, and 3.0-fold risk increases for patients aged 70-74, 75-79, and 80 plus years, respectively, compared with the under 60 years age group.
The strongest predictor of perioperative stroke was previous stroke, which raised patients' risk 4.2-fold. Diabetes, hypertension, peripheral vascular disease, and renal failure also conferred significantly increased risks for stroke, with increases ranging from 1.3- to 1.7-fold. Use of statins or clopidogrel tended to reduce perioperative stroke risk.
In an accompanying editorial, Robert Sanders (Imperial College London, UK) and Hilary Grocott (University of Manitoba, Winnipeg, Canada) note that the study "also demonstrates the importance of considering a contemporary group of patients when determining perioperative risks," explaining that "with the continued evolution of surgical and anesthetic techniques, perioperative risk may also have changed in recent times."
The studies that prompted caution in referring elderly patients for CABG because of high stroke risk are now about 20 years old, they point out.
"Nonetheless, we must not downplay the importance of age, as there remained a strong association between advanced age and perioperative mortality," say Sanders and Grocott. "Age cannot be discounted as [an] important variable for predicting overall perioperative risk after cardiac surgery."
They conclude: "Additional prospective data are required to guide the care of elderly patients undergoing surgery."
MedWire (www.medwire-news.md) is an independent clinical news service provided by Current Medicine Group, a trading division of Springer Healthcare Limited. © Springer Healthcare Ltd; 2010
By Eleanor McDermid