Testing blood for N-terminal pro b-type natriuretic peptide (NT-proBNP) appears to have value as a preoperative test to predict risk of cardiovascular (CV) events, according to a study published December 24 online in Annals of Internal Medicine. The results may prompt a rethink of cardiology guidelines, which currently do not advise its use in this setting, and clinical practice.
The retrospective study analyzed the association of higher levels of NT-ProBNP prior to surgery with risk for cardiovascular and vascular complications following procedures in 10,402 patients who were undergoing noncardiac surgery with an overnight stay. Participants had been enrolled in the Vascular Events in Noncardiac Surgery Patients Cohort Evaluation (VISION) study, and NT-proBNP and troponin T levels had been tested prior to surgery.
The study was funded by the Canadian Institutes of Health Research, and the results were reported by Dr. PJ Devereaux, PhD, a professor of medicine at McMaster University and a cardiologist at Hamilton Health Sciences in Ontario.
Compared with NT-proBNP levels less than 100 pg/mL, those with levels of 100 pg/mL to less than 200 pg/mL, 200 pg/mL to less than 1500 pg/mL, and 1500 pg/mL or greater were associated with significantly higher event rates (adjusted hazard ratios of 2.27, 3.63, and 5.82, respectively), the authors reported.
"Adding NT-proBNP thresholds to clinical stratiﬁcation (that is, the Revised Cardiac Risk Index [RCRI]) resulted in a net absolute reclassiﬁcation improvement of 258 per 1,000 patients," Deveraux and colleagues reported. "Preoperative NT-proBNP values were also statistically signiﬁcantly associated with 30-day all-cause mortality."
A common complication
Myocardial injury after noncardiac surgery (MINS) is the most common major vascular complication after surgery and is associated with perioperative death, and accurate preoperative cardiovascular risk prediction is important for guiding decisions about whether surgery is appropriate and how patients should be managed, the authors noted.
In an accompanying editorial, also published in the Annals of Internal Medicine on December 24, New York University cardiologists Drs. Arman Qamar and Sripal Bangalore wrote that the results represent the largest study evaluating NT-proBNP in a preoperative setting. The test is sensitive for detecting myocardial wall stress and structural changes, they noted, so the findings are not surprising.
"Nonetheless, this study is a major step forward in advancing the use of biomarkers for preoperative cardiac risk assessment," Qamar and Bangalore wrote.
They noted that the evidence for NT-proBNP testing as a prognostic tool for stratifying risk before surgery is "unquestionable," yet this is not part of routine clinical practice nor is it advised for routine use by cardiology associations in the U.S. and Europe, including the American College of Cardiology and American Heart Association, as well as the European Society of Cardiology.
"Thus, given the well-known limitations of clinical risk indices and noninvasive cardiac diagnostic testing in preoperative risk prediction, evaluation of NT-proBNP in addition to clinical factors offers a readily available, precise, and inexpensive tool for risk stratification," the authors wrote in their editorial. "However, whether NT-proBNP–driven perioperative management reduces the risk for cardiovascular events is unknown and should be investigated."