Comparison of Transthoracic Echocardiography With N-Terminal Pro-Brain Natriuretic Peptide as a Tool for Risk Stratification of Patients Undergoing Major Noncardiac Surgery

Background and Objectives: The role of preoperative transthoracic echocardiography (TTE) for the risk stratification has not been well investigated yet. We compared the predictive power of TTE with N-terminal pro-brain natriuretic peptide (NT-proBNP), a representative biomarker that predicts perioperative cardiovascular risk, and investigated whether these tests have incremental value to the clinically determined risk. Subjects and Methods: We evaluated the Revised Cardiac Risk Index (RCRI), TTE, and NT-proBNP in 1,923 noncardiac surgery cases. The primary endpoint was a perioperative major cardiovascular event (PMCE), which was defined by any single or combined event of secondary endpoints including myocardial infarction, development of pulmonary edema, or primary cardiovascular death within 30 days after surgery. Results: All echocardiographic parameters including left ventricular ejection fraction, regional wall motion score index, and transmitral early diastolic velocity/tissue Doppler mitral annular early diastolic velocity (E/E') were predictive of PMCE (c-statistics=0.579 +/- 0.019 to 0.589 +/- 0.015), but none of these parameters were better than the clinically determined RCRI (c-statistics=0.594 +/- 0.019) and were inferior to NT-proBNP (c-statistics=0.748 +/- 0.019, p<0.001). The predictive power of RCRI {adjusted relative risk (RR)=1.4} could be improved by addition of echocardiographic parameters (adjusted RR=1.8, p<0.001), but not to that extent as by addition of NT-proBNP to RCRI (adjusted RR=3.7, p<0.001). Conclusion: TTE was modestly predictive of perioperative cardiovascular events but was not superior to NT-proBNP. Moreover, it did not have incremental value to the clinically determined risk. The results of our study did not support the use of routine echocardiography before noncardiac surgery.