Dissecting the correlates of N-terminal prohormone brain natriuretic peptide in acute infective endocarditis

Abstract

Purpose: To explore the prognostic value and the correlates of NT-proBNP in patients with acute infective endocarditis, a life-threatening disease, with an often unpredictable outcome given by the lack of reliable prognostic parameters.

Methods: We retrospectively studied 337 patients admitted to our centre between January 1, 2006 and September 30, 2020 with available NT-proBNP level at admission. Our analyses were performed considering NT-proBNP as both a categorical variable, using the median value as the cut-off level, and numerical variable. Study end points were in-hospital mortality, cardiac surgery and 1 year survival.

Results: NT-proBNP was an independent predictor of in-hospital mortality (OR 14.9 [95%C.I. 2.46-90.9]; P = .003). Levels below 2926 pg/mL were highly predictive of a favorable in-hospital outcome (negative predictive value 96.6%). Patients with higher NT-proBNP levels showed a significantly lower survival rate at 1 year follow-up (log-rank P = .005). NT-proBNP was strongly associated with chronic kidney disease (P < .001) and significantly higher in patients with prior chronic heart failure (P = .001). NT-proBNP was tightly related to staphylococcal IE (P = .001) as well as with higher CRP and hs-troponin I (P = 0.023, P < .001, respectively).

Conclusion: Our results confirm the remarkable prognostic role of NT-proBNP in patients with IE and provide novel evidences of its multifaceted correlates in this unique clinical setting. Our data strongly support the incorporation of NT-proBNP into the current diagnostic work-up of IE.

Keywords: Endocarditis; Heart failure; NT-proBNP; Prognostic value.

Fig. 1

NT-proBNP levels in different IE patient subgroups (log-transformed NT-proBNP levels are shown). Each boxplot depicts the NT-proBNP median levels among each subgroup of IE patients. Panel A Microbiological isolates (Staphylococcus spp vs others). Panel B Prior heart failure. Panel C Heart valve surgery. Panel D type of valve (native vs prosthetic). Panel E Vegetation location (aortic vs mitral). Panel F in-hospital outcome (alive vs deceased)

Fig. 2

Receiver Operating Characteristic (ROC) curve analysis evaluating the predictive value of in-hospital mortality of the NT-proBNP and C-reative protein (CRP).For each of the analysed biomarker the area under the ROC curve is shown. The best cut-off for NT-proBNP (blue line) is 2926.5 pg/mL whether the cut-off for CRP (green line) is 6.1 mg/dL

Fig. 3

Kaplan–Meier survival curves depicting the cumulative rate of survival at 1 year according to NT-proBNP levels above or below the median total cohort value (1689 pg/mL). The number of cases at risk according to the displayed time-lime is shown at the bottom