Soluble ST2 for Risk Stratification and the Prediction of Mortality in Patients Undergoing Transcatheter Aortic Valve Implantation

Blood biomarkers in left-sided valvular heart disease

Valvular heart disease (VHD) is a common condition that poses several challenges from the standpoints of diagnosis and therapeutic management. While several studies have explored the role of blood biomarkers in assessing the severity and risk of progression of VHD, as well as in evaluating related cardiac damage and predicting the occurrence of adverse events, blood biomarkers are generally not considered criteria to trigger valve intervention in the latest European and American guidelines for VHD management. This review article provides an up-to-date overview of the utility of blood biomarkers to (i) assess the presence, severity, and progression of left-sided VHD; (ii) establish the presence and extent of cardiovascular damage; (iii) predict clinical outcomes before and after valve interventions; and (iv) identify patients at risk for early structural valve deterioration, valve thrombosis, and paravalvular leak.

A Novel Frailty Score Based on Laboratory Parameters (FIMS Score) for the Management of Older Patients with Severe Aortic Stenosis

This study aimed to develop a novel score based on common laboratory parameters able to identify frail and sarcopenic patients as well as predict mortality in elderly patients with severe aortic stenosis (AS) for tailored clinical decision-making. A total of 109 patients (83 ± 5 years; females, 68%) with AS underwent a multidisciplinary pre-operative assessment and finalized a "frailty-based management" for the AS interventional treatment. Laboratory parameters of statistically significant differences between sarcopenic and non-sarcopenic individuals were tested in the structural equation model (SEM) to build a Frailty Inflammation Malnutrition and Sarcopenia score (FIMS score). Mortality at 20 months of follow-up was considered an outcome. FIMS score, in particular, the cut-off value ≥ 1.28 was able to identify "frail" and "early frail" patients and predict mortality with a sensitivity of 83.3% and 82.6%, respectively (p = 0.001) and was an independent determinant associated with a higher risk of mortality (HR 5.382; p-value = 0.002). The FIMS score, easily achievable and usable in clinical practice, was able to identify frail and sarcopenic patients as well as predict their adverse clinical outcomes. This score could provide appropriate guidance during decision-making regarding elderly patients with severe AS.

Soluble ST2 levels are related to replacement myocardial fibrosis in severe aortic stenosis

INTRODUCTION AND OBJECTIVES

Patients with aortic stenosis (AS) exhibit left ventricular (LV) remodeling and replacement myocardial fibrosis (RMF). Whether sST2 is associated with RMF measured by cardiac magnetic resonance and with sex remains unknown.

METHODS

We recruited 79 consecutive patients (73.0 [68.0-78.0] years; 61% men) with severe isolated AS underdoing valve replacement. RMF was identified and quantified by late gadolinium enhancement (LGE). Serum sST2 levels were determined.

RESULTS

RMF was associated with higher circulating sST2 levels, LV hypertrophy and dilation, and lower LV ejection fraction. All patients with LV dysfunction had RMF. Circulating levels of sST2 ≥ 28.8 ng/mL were associated with RMF and greater LV hypertrophy. LGE mass was correlated with LV remodeling and sST2. Of note, sST2 levels were also associated with the RMF pattern, being higher in midwall than in subendocardial fibrosis. Multivariate analyses showed that only LV ejection fraction and sST2 levels were associated with RMF. Moreover, men had higher levels of sST2 and RMF. RMF was associated with higher LV dilation and hypertrophy only in men and was correlated with LGE mass.

CONCLUSIONS

SST2 was an independent factor for RMF in patients with severe isolated AS. The presence of RMF was predicted by sST2 ≥ 28.2 ng/mL, and was associated with greater LV hypertrophy. sST2 expression and clinical associations may be sex-specific.

68Ga-labeled WVP peptide as a novel PET probe for molecular biological diagnosis of unstable thoracic aortic aneurysm and early dissection: an animal study

OBJECTIVE

Type IV collagen (Col-IV) is a prospective biomarker for diagnosing and treating of unstable thoracic aortic aneurysm and dissection (TAAD). This study aims to evaluate the feasibility of 68Ga-labeled WVP peptide (68Ga-DOTA-WVP) as a novel Col-IV-targeted probe for TAAD biological diagnosis using PET/CT.

METHODS

WVP peptide was modified with bifunctional chelator DOTA for 68Ga radiolabeling. Immunohistochemical staining was used to evaluate the expression and location of Col-IV and elastin in aortas treated with 3-aminopropionitrile fumarate (BAPN) at different time points (0, 2, and 4 weeks). The imaging performance of 68Ga-DOTA-WVP was investigated using Micro-PET/CT in a BAPN-induced TAAD mouse model. The relationship between 68Ga-DOTA-WVP uptake in aortic lesions and the serum levels of TAAD-related biomarkers including D-dimer, C-reactive protein (CRP), and serum soluble suppression of tumorigenicity-2 (sST2) was also analyzed.

RESULTS

68Ga-DOTA-WVP was readily prepared with high radiochemical purity and stability in vitro. 68Ga-DOTA-WVP Micro-PET/CT could detect Col-IV exposure of unstable aneurysms and early dissection in BAPN-induced TAAD mice, but little 68Ga-DOTA-WVP uptake was shown in the control group at each imaging time point. The differences of Col-IV expression and distribution of 68Ga-DOTA-WVP both in TAAD and control groups further verified the imaging efficiency of 68Ga-DOTA-WVP PET/CT. Additionally, a higher sST2 level was found in the imaging positive (n = 14) than the negative (n = 8) group (9.60 ± 1.14 vs. 8.44 ± 0.52, P = 0.014).

CONCLUSION

68Ga-DOTA-WVP could trace the exposure and abnormal deposition of Col-IV in enlarged and early injured aortas, showing a potential for biological diagnosis, whole-body screening, and progression monitoring of TAAD.

The ST2/IL-33 Pathway in Adult and Paediatric Heart Disease and Transplantation

ST2 is a member of interleukin 1 receptor family with soluble sST2 and transmembrane ST2L isoforms. The ligand of ST2 is IL-33, which determines the activation of numerous intracytoplasmic mediators following the binding with ST2L and IL-1RAcP, leading to nuclear signal and cardiovascular effect. Differently, sST2 is released in the blood and works as a decoy receptor, binding IL-33 and blocking IL-33/ST2L interaction. sST2 is mainly involved in maintaining homeostasis and/or alterations of different tissues, as counterbalance/activation of IL-33/ST2L axis is typically involved in the development of fibrosis, tissue damage, inflammation and remodeling. sST2 has been described in different clinical reports as a fundamental prognostic marker in patients with cardiovascular disease, as well as marker for the treatment monitoring of patients with heart failure; however, further studies are needed to better elucidate its role. In this review we reported the current knowledge about its role in coronary artery disease, heart failure, heart transplantation, heart valve disease, pulmonary arterial hypertension, and cardiovascular interventions.

The mechanistic pathways of oxidative stress in aortic stenosis and clinical implications

Despite the elucidation of the pathways behind the development of aortic stenosis (AS), there remains no effective medical treatment to slow or reverse its progress. Instead, the gold standard of care in severe or symptomatic AS is replacement of the aortic valve. Oxidative stress is implicated, both directly as well as indirectly, in lipid infiltration, inflammation and fibro-calcification, all of which are key processes underlying the pathophysiology of degenerative AS. This culminates in the breakdown of the extracellular matrix, differentiation of the valvular interstitial cells into an osteogenic phenotype, and finally, calcium deposition as well as thickening of the aortic valve. Oxidative stress is thus a promising and potential therapeutic target for the treatment of AS. Several studies focusing on the mitigation of oxidative stress in the context of AS have shown some success in animal and in vitro models, however similar benefits have yet to be seen in clinical trials. Statin therapy, once thought to be the key to the treatment of AS, has yielded disappointing results, however newer lipid lowering therapies may hold some promise. Other potential therapies, such as manipulation of microRNAs, blockade of the renin-angiotensin-aldosterone system and the use of dipeptidylpeptidase-4 inhibitors will also be reviewed.

Severe Aortic Valve Stenosis and Pulmonary Hypertension: A Systematic Review of Non-Invasive Ways of Risk Stratification, Especially in Patients Undergoing Transcatheter Aortic Valve Replacement

Patients with severe aortic valve stenosis and concomitant pulmonary hypertension show a significantly reduced survival prognosis. Right heart catheterization as a preoperative diagnostic tool to determine pulmonary hypertension has been largely abandoned in recent years in favor of echocardiographic criteria. Clinically, determination of echocardiographically estimated systolic pulmonary artery pressure falls far short of invasive right heart catheterization data in terms of accuracy. The aim of the present systematic review was to highlight noninvasive possibilities for the detection of pulmonary hypertension in patients with severe aortic valve stenosis, with a special focus on cardiovascular biomarkers. A total of 525 publications regarding echocardiography, cardiovascular imaging and biomarkers related to severe aortic valve stenosis and pulmonary hypertension were analyzed in a systematic database analysis using PubMed Central®. Finally, 39 publications were included in the following review. It was shown that the current scientific data situation, especially regarding cardiovascular biomarkers as non-invasive diagnostic tools for the determination of pulmonary hypertension in severe aortic valve stenosis patients, is poor. Thus, there is a great scientific potential to combine different biomarkers (biomarker scores) in a non-invasive way to determine the presence or absence of PH.

Soluble ST2 as a Potential Biomarker for Risk Assessment of Pulmonary Hypertension in Patients Undergoing TAVR?

Background: Severe aortic valve stenosis (AS) is associated with pulmonary hypertension (PH) and has been shown to limit patient survival. Soluble suppression of tumorigenicity-2 (sST2) is a cardiovascular biomarker that has proven to be an important prognostic marker for survival in patients undergoing transcatheter aortic valve replacement (TAVR). The aim of this study was to assess the importance of the sST2 biomarker for risk stratification in patients with severe AS in presence or absence of PH. Methods: In 260 patients with severe AS undergoing TAVR procedure, sST2 serum level concentrations were analyzed. Right heart catheter measurements were performed in 152 patients, with no PH detection in 43 patients and with PH detection in 109 patients. Correlation analyses according to Spearman, AUROC analyses and Kaplan–Meier curves were calculated. Results: Patients with severe AS and PH showed significantly higher serum sST2 concentrations (p = 0.006). The sST2 cut-off value for non-PH patients regarding 1-year survival yielded 5521.15 pg/mL, whereas the cut-off value of PH patients was at a considerably higher level of 10,268.78 pg/mL. A cut-off value of 6990.12 pg/mL was related with a significant probability of PH presence. Survival curves showed that patients with severe AS and PH not only had higher 1-year mortality, but also that increased levels of sST2 plasma concentration were associated with earlier death. Conclusion: sST2 definitely has the potential to provide information about the presence of PH in patients with severe AS, in a noninvasive way.

Biomarkers Associated with Mortality in Aortic Stenosis: A Systematic Review and Meta-Analysis

The optimal timing of aortic valve replacement (AVR) remains controversial. Several biomarkers reflect the underlying pathophysiological processes in aortic stenosis (AS) and may be of use as mortality predictors. The aim of this systematic review and meta-analysis is to evaluate the blood biomarkers utilised in AS and assess whether they associate with mortality. PubMed and Embase were searched for studies reporting baseline biomarker level and mortality outcomes in patients with AS. A total of 83 studies met the inclusion criteria and were systematically reviewed. Of these, 21 reporting brain natriuretic peptide (BNP), N-terminal pro B-type natriuretic peptide (NT-proBNP), Troponin and Galectin-3 were meta-analysed. Pooled analysis demonstrated that all-cause mortality was significantly associated with elevated baseline levels of BNP (HR 2.59; 95% CI 1.95–3.44; p < 0.00001), NT-proBNP (HR 1.73; 95% CI 1.45–2.06; p = 0.00001), Troponin (HR 1.65; 95% CI 1.31–2.07; p < 0.0001) and Galectin-3 (HR 1.82; 95% CI 1.27–2.61; p < 0.001) compared to lower baseline biomarker levels. Elevated levels of baseline BNP, NT-proBNP, Troponin and Galectin-3 were associated with increased all-cause mortality in a population of patients with AS. Therefore, a change in biomarker level could be considered to refine optimal timing of intervention. The results of this meta-analysis highlight the importance of biomarkers in risk stratification of AS, regardless of symptom status.

Periprocedural Changes of NT-proBNP Are Associated With Survival After Transcatheter Aortic Valve Implantation

Background

Cardiovascular biomarkers constitute promising tools for improved risk stratification and prediction of outcome in patients undergoing transcatheter aortic valve implantation. We examined the association of periprocedural changes of NT‐proBNP (N‐terminal pro–B‐type natriuretic peptide) with survival after transcatheter aortic valve implantation.

Methods and Results

NT‐proBNP levels were measured in 704 patients before transcatheter aortic valve implantation and at discharge. Patients were grouped as responders and nonresponders depending on an NT‐proBNP–based ratio (postprocedural NT‐proBNP at discharge/preprocedural NT‐proBNP). Overall, 376 of 704 patients showed a postprocedural decrease in NT‐proBNP levels (NT‐proBNP ratio <1). Responders and nonresponders differed significantly regarding median preprocedural (2822 versus 1187 pg/mL, P<0.001) and postprocedural (1258 versus 3009 pg/mL, P<0.001) NT‐proBNP levels. Patients in the nonresponder group showed higher prevalence of atrial fibrillation (47.0% versus 39.4%, P=0.042), arterial hypertension (94.2% versus 87.5%, P=0.002), renal impairment (77.4% versus 69.1%, P=0.013), and peripheral artery disease (24.4% versus 14.6%, P=0.001). In contrast, patients in the responder group had higher prevalence of moderately reduced left ventricular ejection fraction (17.3% versus 11.0%, P=0.017), lower calculated aortic valve area (0.7 versus 0.8 cm², P<0.001), and higher mean pressure gradient (41 versus 35 mm Hg, P<0.001). Median follow‐up was 22.6 months. Kaplan–Meier analysis showed a highly significant survival benefit for the responder group compared with the nonresponder group (log‐rank test, P<0.001).

Conclusions

A ratio based on periprocedural changes of NT‐proBNP is a simple tool for better risk stratification and is associated with survival in patients after transcatheter aortic valve implantation.

Soluble ST2 promotes oxidative stress and inflammation in cardiac fibroblasts: an in vitro and in vivo study in aortic stenosis

Background: Soluble ST2 (interleukin 1 receptor-like 1) (sST2) is involved in inflammatory diseases and increased in heart failure (HF). We herein investigated sST2 effects on oxidative stress and inflammation in human cardiac fibroblasts and its pathological role in human aortic stenosis (AS).

Methods and results: Using proteomics and immunodetection approaches, we have identified that sST2 down-regulated mitofusin-1 (MFN-1), a protein involved in mitochondrial fusion, in human cardiac fibroblasts. In parallel, sST2 increased nitrotyrosine, protein oxidation and peroxide production. Moreover, sST2 enhanced the secretion of pro-inflammatory cytokines interleukin (IL)-6, IL-1β and monocyte chemoattractant protein-1 (CCL-2). Pharmacological inhibition of transcriptional factor nuclear factor κB (NFκB) restored MFN-1 levels and improved oxidative status and inflammation in cardiac fibroblasts. Mito-Tempo, a mitochondria-specific superoxide scavenger, as well as Resveratrol, a general antioxidant, attenuated oxidative stress and inflammation induced by sST2. In myocardial biopsies from 26 AS patients, sST2 up-regulation paralleled a decrease in MFN-1. Cardiac sST2 inversely correlated with MFN-1 levels and positively associated with IL-6 and CCL-2 in myocardial biopsies from AS patients.

Conclusions: sST2 affected mitochondrial fusion in human cardiac fibroblasts, increasing oxidative stress production and inflammatory markers secretion. The blockade of NFκB or mitochondrial reactive oxygen species restored MFN-1 expression, improving oxidative stress status and reducing inflammatory markers secretion. In human AS, cardiac sST2 levels associated with oxidative stress and inflammation. The present study reveals a new pathogenic pathway by which sST2 promotes oxidative stress and inflammation contributing to cardiac damage.

Hope and despair: patients' experiences of being ineligible for transcatheter aortic valve implantation

BACKGROUND

Transcatheter aortic valve implantation may be indicated for patients with aortic stenosis and high risk of postoperative mortality. The assessment of suitability for transcatheter aortic valve implantation requires consensus agreement of a team of cardiologists and cardiac surgeons. The burden of comorbidities, frailty and cognitive impairment are factors included when risks for transcatheter aortic valve implantation are balanced against the expected benefits. Although transcatheter aortic valve implantation is a possibility for many, there are still ineligible patients. Knowledge of their experiences of being deemed ineligible are lacking.

AIM

The aim of this study was to explore patients' experiences of being considered for transcatheter aortic valve implantation but judged ineligible.

METHODS

Individual in-depth interviews were performed with eight persons, and qualitative content analysis was used for the analysis.

RESULTS

Being ineligible for transcatheter aortic valve implantation may induce both hope and despair. Hope was linked to experiences of acceptance, relief of symptoms, support and control; despair was associated with feelings of being missed and abandoned, and of grief and insecurity. Some expressed great anxiety, since their incurable heart disease meant an imminent death. Others were more concerned over practical problems that affected everyday life.

CONCLUSION

Being ineligible for transcatheter aortic valve implantation does not necessarily lead to despair. Hope is built through relationships, continuity and support. A combination of person-centred care and palliative care during the end-of-life phase should be offered to patients in order to help clients re-conceptualise hope during this stage of their illness. Cardiovascular nurses in the transcatheter aortic valve implantation team are suitable to facilitate continued care based on the patient's needs, desires and local conditions.

Meta-Analysis of Impact of Baseline N-TerminalPro-Brain Natriuretic Peptide Levels on SurvivalAfter Transcatheter Aortic Valve Implantation for Aortic Stenosis

We performed a meta-analysis of currently available studies investigating impact of baseline N-terminal pro-brain natriuretic peptide (NT-proBNP) on mortality after transcatheter aortic valve implantation (TAVI) for aortic stenosis (AS). MEDLINE and EMBASE were searched through August 2018 using PubMed and OVID. Studies considered for inclusion met the following criteria: the design was a study researching impact of baseline NT-proBNP levels on survival; the study population was patients underwent TAVI for AS; outcomes included all-cause mortality. For each study, we directly extracted odds ratio (ORs) or hazard ratios (HRs) of mortality (for high vs low baseline NT-proBNP); and generated ORs using mortality rates in both patients with high and low levels of baseline NT-proBNP. Study-specific estimates were combined using inverse variance-weighted averages of logarithmic ORs/HRs in the random-effects model. We identified 16 eligible studies including a total of 3,679 patients who underwent TAVI for AS. Pooled analyses demonstrated that high levels of baseline NT-proBNP were associated with a statistically nonsignificant increase in early (30-day or 2-month) mortality (pooled OR, 1.60; 95% confidence interval, 0.84 to 3.04; p = 0.15) and a statistically significant increase in midterm (6-month to 4-year) mortality (pooled OR/HR, 1.88; 95% confidence interval, 1.54 to 2.28; p < 0.00001). Although funnel-plot asymmetry suggesting publication bias was detected, adjusting for funnel-plot asymmetry indicated an association of high levels of baseline NT-proBNP with a still significant increase in midterm mortality. In conclusion, high levels of baseline NT-proBNP predict increased midterm, not early, mortality after TAVI for AS.

Tropisetron inhibits sepsis by repressing hyper-inflammation and regulating the cardiac action potential in rat models

OBJECTIVE

The objective of the present investigation was to explore the possible effect of the 5-HT3 receptor antagonist tropisetron on the expression levels of the inflammatory factors interleukin 6 (IL-6), creatine kinase isoenzyme (CK-MB), soluble growth stimulating gene 2 protein (sST2) and immunoglobulin E (IgE), as well as the cardiac action potential in septic rats.

METHODS

The cecal ligation and perforation (CLP) method was utilized to construct abdominal infarction in rats. A total of 68 male adult Sprague Dawley rats were used, including 40 for assessing survival and 28 for detecting the expression levels of IL-6 and IgE, myocardial injury, cardiac dysfunction and the cardiac action potential. These 28 rats were divided into the sham (6 rats), sham + Tropisetron (6 rats), CLP (8 rats) and CLP + Tropisetron (8 rats) groups. Twenty-four hours after establishment of the sepsis rat model, immunohistochemistry was used to analyze 5-HT3 receptor protein expression, and enzyme-linked immunosorbent assay (ELISA) was employed to monitor the serum levels of IL-6, CKMB, sST2 and IgE. Furthermore, the structure of the myocardium in various groups was examined by H&E staining.

RESULTS

The levels of IL-6, CK-MB, sST2 and IgE in the sepsis group were significantly higher than those of the sham group (P <  0.01). Furthermore, the heart rate in the sepsis group was lower than that of the sham group (P <  0.01), and the time of atrial ventricular action potential in the sepsis group was longer than that of the sham group (P <  0.05). In addition, immunohistochemical analyses showed that the area, intensity and index of 5-HT3 receptor in the sepsis group were significantly lower than those of the sham group (P <  0.01). Importantly, the 5-HT3 receptor antagonist Tropisetron exhibited significant inhibitory effects IL-6, CK-MB, sST2 and IgE expression levels, and inductive effects on atrial ventricular action potential in the sepsis group.

CONCLUSIONS

Sepsis leads to systemic inflammatory reaction, resulting in myocardial injury, structural changes and immune imbalance. The inhibitory effect of tropisetron on inflammation, and the regulatory inflammatory disorder by the efferent vagus nerve may be one of the important mechanisms leading to cardiac electrophysiological changes in sepsis.

sST2 as a novel biomarker for the prediction of in-hospital mortality after coronary artery bypass grafting

Objectives: Soluble suppression of tumorigenicity 2 (sST2) biomarker is an emerging predictor of adverse clinical outcomes, but its prognostic value for in-hospital mortality after coronary artery bypass grafting (CABG) is not well understood. This study measured the association between operative sST2 levels and in-hospital mortality after CABG. Methods: A prospective cohort of 1560 CABG patients were analyzed from the Northern New England Cardiovascular Disease Study Group Biomarker Study. The primary outcome was in-hospital mortality after CABG surgery (n = 32). Results: After risk adjustment, patients in the third tercile of pre-, post- and pre-to-postoperative sST2 values experienced significantly greater odds of in-hospital death compared to patients in the first tercile of sST2 values. The addition of both postoperative and pre-to-postoperative sST2 biomarker significantly improved ability to predict in-hospital mortality status following CABG surgery, compared to using the EuroSCORE II mortality model alone, (c-statistic: 0.83 [95% CI: 0.75, 0.92], p value 0.0213) and (c-statistic: 0.83 [95% CI: 0.75, 0.92], p value 0.0215), respectively. Conclusion: sST2 values are associated with in-hospital mortality after CABG surgery and postoperative and pre-to-post operative sST2 values improve prediction. Our findings suggest that sST2 can be used as a biomarker to identify adult patients at greatest risk of in-hospital death after CABG surgery.

Can Blood Biomarkers Help Predicting Outcome in Transcatheter Aortic Valve Implantation?

Transcatheter aortic valve implantation (TAVI) has become the method of choice for patients with severe aortic valve stenosis, who are ineligible or at high risk for surgery. In this high risk patient population, early and late mortality and rehospitalization rates after TAVI are still relatively high. In spite of recent improvements in procedural TAVI, and establishment of risk models for poor outcome, determining individual risk remains challenging. In this context, current data from several small studies strongly suggest that blood biomarkers of myocardial injury, cardiac mechanical stretch, inflammation, and hemostasis imbalance might play an important role by providing informations on patient risk at baseline, and postprocedural progression of patient clinical conditions from days up to years post-TAVI. Although the role of biomarkers for predicting survival post-TAVI remains to be validated in large randomized studies, implementing biomarkers in clinical practice might improve risk stratification, thereby further reducing TAVI-associated morbidity and mortality.

Prognostic value of soluble ST2 postaortic valve replacement: a meta-analysis

Objectives

Soluble suppression of tumorigenicity 2 (sST2) is a member of the interleukin-1 receptor family and a modulator of hypertrophic and fibrotic responses. Its prognostic value for patients undergoing aortic valve replacement (AVR) has been examined in prospective studies but to date, there has been no systematic evaluation or meta-analysis on this issue.

Methods

PubMed and Embase were searched until 1 October 2017 for studies that evaluated the relationship between sST2 levels and mortality after AVR.

Results

A total of 18 and 37 entries were retrieved from both databases, from which four studies were included in the final meta-analysis. In a total of 1154 subjects (50% male, mean age 80±10 years old, mean follow-up 14 months), elevated sST2 levels were significantly associated with a 44% increase in the risk of all-cause mortality (HR 1.44, 95% CI 1.30 to 1.60, p<0.0001; I²: 44%).

Conclusions

sST2 significantly predicts all-cause mortality in patients who have undergone AVR, but this conclusion is limited by the small number of patients. Larger prospective studies are required to better elucidate its value for risk stratification in this patient population.