BUENOS AIRES (Reuters Health) - Diabetic patients undergoing heart bypass surgery can markedly reduce their risk of serious complications by keeping their blood sugar levels in check before the operation, Argentine researchers reported here at the XXXII Argentine Congress of Cardiology.

The study focused on how well patients controlled their hemoglobin A1c (HbA1c) levels, a measure of long-term blood sugar control.

"Every patient should have the HbA1c tested before the intervention," lead author Dr. Diego Lowenstein, of the Favaloro Foundation, in Buenos Aires, told Reuters Health.

"It might even be advisable to delay the surgery until the HbA1c is at least below 7 percent," he added.

An HbA1c level of 4 percent to 6 percent is typically considered normal, although the range can vary depending on the laboratory doing the testing.

Lowenstein, Dr. Maximo Santos and colleagues studied 56 diabetic patients undergoing heart bypass surgery. Thirty-five patients (62.5 percent) had a preoperative HbA1c level higher than 7 percent.

The researchers found that the higher the value of HbA1c, the higher the risk of complications. The researchers calculated that each percentage point increase in HbA1c level was linked to a 1.7-fold increased risk of major complications, such as overwhelming infection, stroke, and in-hospital death.

Despite the relatively small number of patients, the study suggests that heart surgeons should take HbA1c into account, the investigators believe.

"It is a cheap test, and if your patient has a high HbA1c level you can reduce his surgical risk in less than 2 months. It is well worth the delay," Lowenstein concluded.