Dynamic LVEF Decline and Serum NT-proBNP and Uric Acid Levels before Heart Transplantation are Independent Predictors of Adverse Outcomes in Young Adult Patients with Dilated Cardiomyopathy

Abstract

Background: The present study investigated the predictors of adverse outcomes in young adult patients with dilated cardiomyopathy (DCM) who underwent heart transplantation (HTx).

Methods: Twenty-four young adult patients (aged 18-45 years) with DCM who underwent HTx in our hospital from January 2012 to December 2022 were included in this retrospective analysis. Pre- and post-HTx data were collected for echocardiography, N-terminal pro-brain natriuretic peptide (NT-proBNP), and uric acid (UA). Data collected at the time of DCM diagnosis were designated as baseline data. Post-HTx assessments were conducted at 1 week and 3, 6, 12, and 36 months post-HTx. The primary endpoint was defined as any adverse event, including left ventricular ejection fraction (LVEF) $<$ 50% (n = 3), 50% increase in right or left ventricular diameter (n = 12), or death (n = 2). Patients were categorized into a non-adverse-event group (n = 12) or an adverse-event group (n = 12).

Results: Baseline NT-proBNP (p = 0.014) and UA (p = 0.012) were significantly higher in the adverse-event group than in the non-adverse-event group. Baseline NT-proBNP $>$ 7390 pg/mL (relative risk (RR) = 7.412, p = 0.046), UA $>$ 542 µmol/L (RR = 8.838, 95% confidence interval (95% CI) = 1.541-50.694, p = 0.014), and sustained reduction in LVEF ( $\ge$ 3%) over a 2-year pharmacological treatment prior to HTx (RR = 3.252, p = 0.046) were significantly associated with an increased risk of adverse events post-HTx.

Conclusions: In young adult DCM patients post-HTx, heightened baseline levels of NT-proBNP and UA levels and a sustained reduction in LVEF over time prior to undergoing an HTx are significantly associated with an increased risk of adverse events post-HTx. Future studies are needed to observe whether individualized monitoring strategies could reduce the incidence of adverse events following HTx in these patients.

Keywords: NT-proBNP; dilated cardiomyopathy; heart transplantation; uric acid; ventricular remodeling; young adults.

Fig. 1.

Study flowchart. DCM, dilated cardiomyopathy; HTx, heart transplantation.

Fig. 2.

Bar plots with estimated marginal mean $\mathrm{\pm }$ 1 standard error (SE), illustrating dynamic change in LVEF (A), LVD (B), RVD (C), Ln NT-proBNP (D), and UA (E) at 3 months (T1), 6 months (T2), 12 months (T3), and 36 months (T4) post-HTx in DCM patients with and without adverse events. DCM, dilated cardiomyopathy; HTx, heart transplantation; Ln NT-proBNP, natural logarithmic transformed N-terminal pro-brain natriuretic peptide; LVD, end-diastolic left ventricular diameter; LVEF, left ventricular ejection fraction; RVD, end-diastolic right ventricular middle diameter; T0, at 1 week post-HTx; UA, uric acid.

Fig. 3.

Dynamic changes and percentage variations (%, mean $\mathrm{\pm }$ standard deviation) in LVEF (A), LVD (B), and RVD (C) from 1 week (T0) to 36 months (T4) post-HTx in DCM patients. LVD, end-diastolic left ventricular diameter; LVEF, left ventricular ejection fraction; RVD, end-diastolic right ventricular middle diameter; T1, 3 months post-HTx; T2, 6 months post-HTx; T3, 12 months post-HTx; $\uparrow$, represents an increase; $\downarrow$, represents a reduction; HTx, heart transplantation; DCM, dilated cardiomyopathy.

Fig. 4.

Dynamic changes and percentage variations (%, mean $\mathrm{\pm }$ standard deviation) in Ln NT-proBNP (A) and UA (B) from 1 week (T0) to 36 months (T4) post-HTx in DCM patients. Ln NT-proBNP, natural logarithmic transformed N-terminal pro-brain natriuretic peptide; T1, 3 months post-HTx; T2, 6 months post-HTx; T3, 12 months post-HTx; UA, uric acid; $\downarrow$, represents a reduction; HTx, heart transplantation; DCM, dilated cardiomyopathy.