Abstract
Aim: To evaluate the prognostic utility of red blood cell
distribution width (RDW) and left ventricular mass index (LVMI) in
patients with hypertrophic cardiomyopathy (HCM).
Patients & methods: This study is a retrospective cohort
analysis. Patients diagnosed with hypertrophic cardiomyopathy at the
First Affiliated Hospital of Sun Yat-sen University from March 2014 to
March 2019 were included . HCM patients were stratified into two groups
based on the occurrence of major adverse cardiac events (MACE).Receiver
operator characteristic (ROC) curves were then constructed and Cox
regression models were employed to gauge the prognostic relevance of RDW
and LVMI for HCM patients. Kaplan-Meier analysis evaluated the survival
and MACE-free rate in patients with different level of RDW and LVMI.
Results: A total of 300 patients with HCM were enrolled in this
study and followed up for 40.56±18.33 months. Among them, 117 MACE
(39.00%), 40 all-cause deaths (13.33%), 29 cardiovascular deaths
(9.67%). The level of RDW, LVMI, creatinine (Cr) and B-type pro-brain
natriuretic peptide (NT-ProBNP) were statistically different between the
MACE group and Non-MACE group (P <0.05). Multivariate
analysis showed that after adjusting for confounding factors, RDW and
LVMI were independent predictors of all-cause mortality and MACE in HCM
patients. ROC showed that RDW>0.13 and
LVMI>181g/m2 are the cut-off value to
predict all-cause mortality and MACE. The AUC of the combination
predicting the occurrence of all-cause mortality and MACE are 0.890 and
0.885 respectively. Kaplan-Meier analysis showed that the survival rate
and MACE-free survival rate of group 1 (RDW≦0.13 and
LVMI≦181g/m2) were significantly higher than group 2
(RDW>0.13 or LVMI>181g/m2),
and group 3 (RDW >0.13 and
LVMI>181g/m2) (P =0.000).
Conclusion: We determined that increased RDW and LVMI was
independently associated with MACE incidence and risk of mortality in
HCM patients. Combined evaluation of RDW and LVMI yielded a more
accurate predictive model of HCM patient outcomes relative to the use of
either of these metrics in isolation. Our research can provide a
theoretical basis in the occurrence of MACE for the high-risk HCM and
intervene them properly and timely.
Keywords: hypertrophic cardiomyopathy, red blood cell
distribution, left ventricular mass index.
Introduction
Hypertrophic cardiomyopathy (HCM) is among the most prevalent forms of
heritable cardiomyopathy, affecting between 1/200 and 1/500 of the
overall general population. Treatment of HCM is generally ineffective,
and the condition tends to steadily progress, ultimately resulting in
the premature death of affected individuals [1-3]. While HCM affects
both males and females equally and has been observed in diverse global
populations, its clinical manifestations can vary substantially, ranging
from asymptomatic cases to instances of sudden cardiac death (SCD)
[2]. While SCD is a relatively rare outcome affecting <
1% of HCM patients per year, it is a particularly salient and
concerning risk in those affected by this condition [3],
particularly owing to the frequent coverage by the media of episodes of
sudden cardiac arrest in competitive athletes [2] and to the
difficulty of predicting SCD risk in those with HCM [4]. Several
recent studies have sought to develop reliable approaches to identifying
adults at an elevated risk of SCM. Known risk factors for HCM detected
through these prior efforts have included family history of premature
sudden death [5], unexplained syncope [6], non-sustained
ventricular tachycardia (NSVT) [7], atypical changes in blood
pressure during exercise (either a failure to rise by at least 20 mmHg
or a reduction by at least 20 mmHg during exertion) [8], and severe
left ventricular hypertrophy (≥30mm) [9]. While all of these
predictors have been shown to exhibit a high negative predictive value
(≥90%), they typically exhibit poor positive predictive value (15-20%)
[10]. It is thus urgent that novel approaches to reliably
identifying predictors of HCM be identified in order to guide patient
education and treatment as appropriate.
HCM is associated with a significant increase in cardiac mass,
contributing to SCD, arrhythmias, and adverse left ventricular (LV)
remodeling [11]. Left ventricular mass (LVM) in particular is linked
to tissue fibrosis, and can be used to assess the overall degree of LV
hypertrophy better than many other parameters, as hypertrophy patterns
are often highly variable in regions distant from the maximal LV
thickness [12]. Developments in echocardiographic technologies have
clearly emphasized the utility of LVM in the management of HCM and
associated cardiac hypertrophy, with LVM being negatively correlated
with cardiovascular outcomes in both the general population and in those
with hypertension/aortic stenosis [13], serving as an independent
predictor of cardiovascular risk [14].
Red blood cell distribution width (RDW) is a parameter that can be
measured through routine complete blood counts, assessing the overall
variability of red blood cell (RBC) size distributions in a given
individual [15]. Historically, RDW has primarily been monitored in
the context of anemia differential diagnosis [16]. However, some
studies have recently reported a strong independent relationship between
RDW and adverse outcomes in patients with pulmonary arterial
hypertension [17], coronary disease [16], and heart failure
[18]. The prognostic relevance of RDW in HCM patients, however,
remains to be studied in depth. In one analysis, baseline RDW was shown
to be positively associated with heart failure incidence in HCM patients
without a history of such failure [19]. The relationship between RDW
and other negative outcomes including cardiac death and mortality is
unclear at present. As such, this study was conducted to evaluate the
relevance of RDW and LVMI alone and in combination as predictors of
negative cardiac outcomes and all-cause death in HCM patients.
Patients & Methods