Can NT-proBNP level substitute myocardial perfusion scans for CV risk assessment in noncardiac surgeries?

Results from a recent study published in BMC Anesthesiology have suggested an extended application of N-terminal pro-b-type natriuretic peptide (NT-proBNP) to evaluate the incidence of postoperative CV complications and take proper measures to reduce these complications before and during surgery.

The study revealed the additive specificity of NT-proBNP over myocardial perfusion scan (MPS) as a technique for stress imaging. This approach spares the extra time and expense that occurs with MPS and reduces false positive results.

Preoperative CV risk assessment is one of the main principles before noncardiac surgeries. According to the latest guideline, Cardiac stress imaging, such as myocardial perfusion scan is a proposed method for cardiovascular risk evaluation. However, previous studies have questioned its efficacy and cost-effectiveness.

Farnoosh Larti, Tehran University of Medical Sciences, Keshavarz Boulevard, Tehran, Iran, and colleagues aimed to evaluate the utility of NT-proBNP level measurement for predicting CV complications in patients who underwent an MPS before surgery and compare the results.

The study included a cohort of 80 patients with a revised cardiac risk index score of one or more who were to undergo moderate to high-risk noncardiac surgeries and met the criteria to undergo an MPS for risk assessment. One week before the surgery, all of them underwent an MPS.

The researchers obtained their preoperative electrocardiograms, troponin levels, and NT-proBNP one day before surgery and then on day three postoperative. The predictive efficacy of MPS and NT-proBNP levels were compared.

The authors reported the following findings:

· Seventy-eight patients underwent surgery, three of which exhibited a rise in troponin level, six showed changes on electrocardiogram, and pulmonary oedema was detected in one, three days after surgery.

· There was no mortality in the patients.

· The sensitivity and specificity of the MPS for predicting postoperative cardiovascular complications were 100% and 66%, respectively.

· MPS also had a positive predictive value of 20% and a negative predictive value of 100%.

· A 332.5 pg/ml cut-off value for NT-proBNP level yielded a sensitivity of 100%, specificity of 79.2%, positive predictive value of 40%, and negative predictive value of 100%.

Compared to MPS, the study revealed the incremental specificity and positive predictive value of NT-proBNP level measurement in the evaluation of preoperative CV risk.

"Given the high costs, disappointing predictive value, and low feasibility of MPS, preoperative NT-proBNP level assessment can be substituted," the researchers wrote.

They added, "This method can be of help to surgeons and anesthesiologists for precise detection of at-risk patients resulting in taking proper measures to reduce the mortality and morbidity of the proposed patients before and during surgeries."

Reference:

Esmati, S., Tavoosi, A., Mehrban, S. et al. NT-proBNP level as a substitute for myocardial perfusion scan in preoperative cardiovascular risk assessment in noncardiac surgery. BMC Anesthesiol 23, 244 (2023). https://doi.org/10.1186/s12871-023-02205-x