NT-proBNP Levels Could Predict Preoperative Risk

Results of a new study are supporting the idea that use of a common cardiac blood test done before surgery could help clinicians predict which patients are at greater risk of adverse events following the procedure.

Within a substudy of the Vascular Events In Noncardiac Surgery Patients Cohort Evaluation (VISION) study, results indicate preoperative assessments indicating increased levels of NT-proBNP was associated with increased risk of cardiac and vascular complications within 30 days in adults undergoing major surgery.

"This simple blood test can be done quickly and easily as part of patient's pre-operative evaluation and can help patients better understand their risk of post-operative complications and make informed decisions about their surgery," said lead investigator Emmanuelle Duceppe, MD, internist and researcher at the Centre Hospitalier de l'Universite de Montreal.

From August 2007 to October 2013, investigators recruited a cohort of more than 18,000 patients from 26 centers in 9 countries for participation in the current study. For inclusion in the current study, patients needed to be at least 45 years of age, not be enrolled in VISION, and undergo inpatient noncardiac surgery with regional or general anesthesia.

All participants in the current study had blood drawn and NT-proBNP levels measured before surgery and troponin T level measured daily up to 3 days after surgery. Participants were notated 30 days after their procedure to determine whether any outcome had occurred.

The primary outcome measure of the study was a composite endpoint of vascular death and myocardial injury after non cardiac surgery (MINS). The secondary outcomes of the study included composite of vascular death or MINS, opposite of all-cause mortality or myocardial infarction, MINS, MI, all-cause mortality, and vascular death.

For the purpose of the analysis, the reference group was classified as having NT-proBNP values less than 100 pg/ml. Investigators then categorized participants into 3 additional groups based on NT-proBNP level ranges.

Of the 10,402 participants included, the mean age was 65 years and 50% were men. The most common procedures in the study were major orthopedic surgeries, major general, and major urology or gynecology—investigators noted 33.3% of patients had low-risk surgeries and 4.4% had urgent or emergent procedures. In regard to concomitant conditions, 20.2% had a history of diabetes, 14.7% had coronary artery disease, 3.3% had congestive heart failure, 7.7% had peripheral vascular disease, and 6.9% had a cerebrovascular event.

When examining the primary endpoint, events occurred in 1269 patients (12.2%) within 30 days of their procedure. Of these, 54 were vascular deaths and 1237 were considered MINS. Compared to patients with normal NT-proBNP levels, patients with levels between 100 to less than 200 pg/mL were at a 2.27-fold (95% CI, 1.90 to 2.70) increased risk of the primary endpoint. Patients with levels between 100 and 200 pg/mL had a 3.63-fold (CI, 3.13 to 4.21) increased risk and patients with levels 1500 pg/mL were at a 5.82-fold (CI, 4.81 to 7.05) increased risk of vascular death or MINS.

Investigators pointed out 12.3% of patient in the 100 to 200 pg/mL group suffered from vascular death or MINS. This figure climbed to 20.8% and 37.5%, respectively, in the 200 to 1500 pg/mL group and the 1500 pg/mL or greater groups. Additionally, investigators concluded preoperative levels were statistically significantly associated with 30-day all-cause mortality.

"Heart injury after non-cardiac surgery is emerging as an important health issue requiring attention. Using CIHR funding, the research group led by PHRI and Dr. Devereaux, has clarified the association between an elevation of a common biomarker and the risk of per-operative morbidity and mortality," said Brian H. Rowe, MD, scientific director at the Institute of Circulatory and Respiratory Health, Canadian Institutes for Health Research.

This study, titled “Preoperative N-Terminal Pro—B-Type Natriuretic Peptide and Cardiovascular Events After Noncardiac Surgery,” was published in the Annals of Internal Medicine.