Prognostic and reclassification value of serum cathepsin S over the GRACE risk score in patients with non-ST-segment elevation acute coronary syndrome

Background

Cathepsin S is an extracellular matrix degradation enzyme that plays an important role in atherosclerotic cardiovascular disease by inducing vasa vasorum development and atherosclerotic plaque rupture.

Purpose

To determine the prognostic and reclassification value of baseline serum cathepsin S after adjustment for the Global Registry of Acute Coronary Events (GRACE) score, which is a clinical guideline recommended risk score in non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods

Serum cathepsin S was measured by ELISA in 1,129 consecutive patients presenting with acute symptoms to the emergency department for whom a final adjudicated diagnosis of NSTE-ACS was made. All-cause mortality or all-cause death/non-fatal myocardial infarction (MI) after a median follow-up of 21 months were evaluated as the primary or secondary study endpoint, respectively. The Net Reclassification Index (NRI) estimated the reclassification predictive value for risk of each end-point of cathepsin S over the GRACE score.

Results

After a median follow-up of 21 months 101 (8.95%) deaths were reported. The combined endpoint of death or non-fatal MI occurred in 176 (15.6%) patients. Dose-response curve analysis adjusted for the effect of age, gender, diabetes mellitus, high-sensitivity-cardiac troponin T, high-sensitivity C-reactive protein, revascularization and index diagnosis revealed a non-linear association of continuous cathepsin S with all-cause death (P=0.036 for non-linearity; adjusted HR=1.60 for 80th vs. 20th percentiles, P=0.038) or with the combined endpoint (P=0.008 for non-linearity, adjusted HR=1.53 for 80th vs. 20th percentiles, P=0.011). Serum cathepsin S maintained its predictive value for all-cause death (adjusted HR=1.70 highest vs. lowest tertile, 95% CI 1.03–2.82, P=0.039) after adjusting for the GRACE Score. Similarly, cathepsin S predicted the combined endpoint of all-cause death or non-fatal MI (adjusted HR=1.67 highest vs. lowest tertile, 95% CI 1.15–2.42, P=0.007) independently of the GRACE Score. When cathepsin S was added over the GRACE Score it correctly reclassified risk for all-cause death in 20% of the population (P=0.004). Similarly, serum Cathepsin S conferred a significant reclassification value over the GRACE score for all-cause death or non-fatal MI in 15.9% of the population.

Conclusions

Serum cathepsin S is a predictor of mortality and improves risk stratification over the GRACE score in patients with NSTE-ACS. The clinical application of cathepsin S as a novel biomarker in NSTE-ACS should be further explored and validated.

Funding Acknowledgement

Type of funding source: Foundation. Main funding source(s): German Heart Foundation

Interferon-gamma inducible protein IP-10 and left ventricular remodelling post-acute myocardial infarction: a longitudinal cardiovascular magnetic resonance imaging substudy of CAPRI clinical trial

Background

Adverse left ventricular (LV) remodelling is associated with development of heart failure and poor outcomes in patients with acute myocardial infarction (AMI). Understanding the immunomodulatory mechanisms of LV remodelling is an essential step for the development of novel therapies. Interferon-γ-inducible protein-10 (IP-10)/CXCL10 is a chemokine involved in the recruitment of activated T cells into sites of tissue inflammation. Although IP-10 was reported to reduce adverse LV remodeling in a preclinical myocardial infarction model, its role in LV remodeling in humans with AMI remains unknown.

Purpose

To determine the clinical predictive value of serum IP-10 in LV remodeling in patients with ST-segment elevation myocardial infarction (STEMI).

Methods

This is a substudy of the double-blind, randomised controlled trial “Evaluating the effectiveness of intravenous ciclosporin on reducing reperfusion injury in patients undergoing primary percutaneous coronary intervention” (CAPRI; ClinicalTrials.gov registry number NCT02390674), which enrolled 52 acute STEMI patients. LV remodeling was assessed by cardiovascular magnetic resonance (CMR) imaging and was defined as the 12-week vs. the 3-day post-myocardial infarction change of the left ventricular ejection fraction (ΔLVEF), LV end-diastolic volume (ΔEDV) or LV end-systolic volume (ΔESV). Serum IP-10 was measured before and 5min, 15min, 30min, 90min and 24h after reperfusion by ELISA. Linear regression analysis was used to determine the independent association of IP-10 with the endpoints of the study.

Results

Serum IP-10 concentration peaked at 30min after reperfusion followed by a 2-fold decrease at the 24h post reperfusion compared to pre-reperfusion levels (P<0.001 for all). Comparison of the 12-week CMR to the baseline CMR imaging revealed that baseline pre-reperfusion as well as 5min, 15min, 30min and 90min, but not 24h, post-reperfusion IP-10 serum levels associated with increased LVEF and decreased ESV at 12-weeks (range correlation coefficient r=[0.35–0.41], P<0.05 with ΔLVEF and r=[−0.33 to −0.44], P<0.05 with ΔESV) indicating that the increase of IP-10 at the acute phase of myocardial infarction confers a cardioprotective role. Multivariable linear regression analysis for ΔLVEF showed that in a model including baseline pre-reperfusion or 5min or 15min or 30min or 90min post-reperfusion IP-10 and age, gender, traditional risk factors (arterial hypertension, body-mass index, hyperlipoproteinemia, diabetes mellitus, smoking, family history of CAD), infarct location, admission high-sensitivity troponin T, door-to-balloon time and ciclosporin treatment, only IP-10 was the independent determinant of ΔLVEF.

Conclusions

Increased serum IP-10 levels early after reperfusion are associated with reverse LV remodeling in patients with STEMI undergoing primary PCI. The clinical application of IP-10 as a novel biomarker of LV remodeling post-AMI should be further explored and validated.

Funding Acknowledgement

Type of funding source: None

265Amyloid beta 1-40 and its upstream regulatory pathway BACE1-AS long noncoding RNA/BACE1 are associated with presence and severity of human atherosclerotic disease

Background

Amyloid-beta (1-40) (Aβ1–40), a proinflammatory and pro-atherosclerotic peptide, is associated with accelerated atherosclerosis and major adverse cardiac events. Abeta1–40 production is mainly dependent on the cleavage of amyloid precursor protein by β-amyloid cleaving enzyme-1 (BACE1), known as beta-secretase. BACE1 antisense (BACE1-AS) is a long noncoding RNA that enhances BACE1 stability.

Objectives

To evaluate the clinical value of plasma amyloid-beta levels and its upstream regulatory pathway BACE1/BACE1-AS in patients with subclinical and established atherosclerotic cardiovascular disease.

Methods

Plasma levels of Aβ40 were measured in 642 consecutively recruited patients with and without clinically overt coronary artery disease (CAD). BACE1-AS lncRNA and BACE1 mRNA expression were measured in peripheral blood mononuclear cells derived from 214 study participants. Intima-media thickness and atheromatous plaques by ultrasonography, markers of arterial wave reflections and pulse wave velocity were used as surrogate markers of subclinical CVD. Cardiovascular risk factors (CVRFs), including impaired glomerular filtration rate (<60 ml/min), smoking, hypertension, hyperlipidemia, diabetes, obesity and increased hsCRP (>2 mg/l) were assessed as a measure of CVRF burden.

Results

Both in non-CAD (n=369) and CAD (n=273) patients, Aβ1–40 was associated with age, aortic and peripheral systolic and pulse pressure, and low GFR (p<0.05 for all). In non-CAD subjects Aβ1–40 also correlated with diabetes and low HDL. Importantly, Aβ1–40 was associated with the presence of any plaque in subjects without CAD (p=0.035) and with increased number of diseased coronary arteries (p=0.022) independently of age, gender and CVRFs. Aβ1–40 plasma levels were increased in the highest tertile of BACE1 and BACE1AS (p<0.05) while their expression levels were highly intercorrelated (r=0.825, P<0.001). BACE1 and BACE1-AS levels progressively increased across the 3 groups of non-CAD (n=145), stable CAD (n=43) and acute myocardial infarction (n=26) patients (p for trend<0.001). Among non-CAD subjects, both BACE1 and BACE1-AS were increased in individuals with >2 CVRFs. Among CAD patients, BACE1-AS was associated with decreased LVEF (<50%) (adjusted OR=1.92 per 1-SD increase, p=0.047) while BACE1 in the highest tertile was associated with 5-fold higher odds for coronary multi-vessel disease (p=0.004) after adjustment for age, gender and CVRFs.

Conclusions

Circulating Aβ1–40 and increased expression of its upstream regulators BACE1/BACE1-AS are intercorrelated and associated with the presence and severity of subclinical and clinically overt atherosclerosis. These findings suggest that BACE1-AS/BACE1-mediated increased availability of Aβ1–40 may play a pivotal role in its adverse cardiovascular effects.

P2541Plasma levels of amyloid beta 1-40 are associated with the rate of progression of carotid subclinical atherosclerosis in postmenopausal women

Background

There is increasingly recognized undetected residual cardiovascular (CV) risk in postmenopausal women, suggesting the need for new risk biomarkers in this population. We have previously shown that amyloid-beta (1–40) (Aβ1–40), a proinflammatory and pro-atherosclerotic peptide, is associated with concurrent subclinical cardiovascular disease (CVD) in the general population and with major adverse cardiac events in patients with established cardiac disease. However, the clinical value of Aβ1–40 in menopause or whether this peptide is linked with an increased rate of progression of atherosclerotic disease is unknown.

Purpose

To examine the association of Aβ1–40 levels with the rate of progression of carotid intima-media thickness (IMT) in postmenopausal women.

Methods

In the settings of a Menopause Clinic, postmenopausal women (n=140) without clinically overt CVD or diabetes were consecutively recruited and re-evaluated after a median follow-up period of 24 months. IMT in the carotid arteries was measured by ultrasonography. The average of maximal IMT (mean cIMT) measured at both left and right common carotid, carotid bulb (cb)and internal carotid (ic) artery were used as the main end-point of the analysis. Aβ1–40 was measured in plasma samples at baseline and follow up. Fasting insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR).

Results

Women with increased plasma levels Aβ1–40 in the highest tertile presented the highest probability to have increased mean cIMT (adjusted OR=2.97, 95% CI 1.18–7.52, p=0.021) independently of age, smoke, hypertension, and hyperlipidemia. After adjustment for HOMA-IR, this association remained significant. Similarly, Aβ1–40 levels were associated with increased mean cb and icIMT (adjusted OR=3.34 for highest versus lower tertile, 95% CI 1.27–8.81, p=0.015). Mean cIMT significantly increased across the follow up period (0.73mm (0.065–0.08) to 0.77mm (0.07–0.089), median increase rate per year 0.024mm, p<0.001). By multi-level linear mixed model analysis, changes in Aβ1–40 levels were associated with increased rate of progression of mean cIMT (4.1% increase per 1-SD increase, p<0.001) after adjustment for differences in follow-up duration and age, hypertension, hyperlipidemia, and smoking. When repeated measurements of HOMA-IR were also considered, this association did not materially change (p=0.021). Similarly, longitudinal changes in Aβ1–40 correlated with the progression of mean cb and icIMT (3.9% increase per 1-SD increase, p=0.001), independently of time to re-evaluation and cardiovascular risk factors.

Conclusion

Aβ1–40 is an independent predictor of the rate of progression of subclinical carotid atherosclerosis in menopausal women. This finding supports the clinical value of Aβ1–40 in menopause and warrants further investigation for its prognostic role in this population.

P4492Peripheral blood mononuclear cell expression of the stabilizing RNA-binding protein HuR is associated with incidence and extent of human atherosclerotic cardiovascular disease

Background

Human Antigen R (HuR) is a stabilizing RNA-binding protein that regulates the expression of several pro-inflammatory molecules. However, its regulation in human atherosclerotic cardiovascular disease remains unknown.

Purpose

To determine the association of peripheral blood mononuclear cell HuR expression with established markers of increased cardiovascular risk and atherosclerosis burden in patients with subclinical or clinically overt coronary artery disease (CAD).

Methods

HuR mRNA expression was measured in peripheral blood mononuclear cells derived from 289 patients with stable CAD or acute myocardial infarction (AMI) and 373 individuals without clinically overt cardiovascular disease (CVD). Structural and functional vascular measurements including intima-media thickness (IMT) and number of atheromatous plaques by carotid and femoral artery ultrasonophaphy, markers of arterial wave reflections by pulse wave analysis and pulse wave velocity were used as surrogate markers of subclinical CVD. The number of angiographically confirmed diseased coronary arteries (>50% stenosis) was used to assess the extent of CAD.

Results

HuR mRNA expression was significantly increased in patients with CAD (both stable and AMI) compared to controls (p=0.039). Subgroup analysis revealed that STEMI patients (n=107) had increased levels of HuR expression compared to NSTEMI (n=49, p=0.03). Among patients with stable CAD (n=133), high HuR expression was independently associated with the number of diseased coronary arteries (OR=1.35 for 1-SD increase in HuR, 95% CI 1.07–1.72, p=0.012), as well as with reduced ejection fraction (EF<45%, OR=1.32 per 1-SD increase, 95% CI 1.05–1.85, p=0.024). Among individuals without CVD, high HuR was associated with lower HDL levels (adjusted beta=-5.2 mg/dl for highest versus lowest quartile, p=0.03) and higher diastolic blood pressure (adjusted beta=3.6 mmHg, p=0.007), while, after adjustment for traditional cardiovascular risk factors, HuR levels in individuals without CVD were independently associated with increased IMT in the common carotid artery (mean increase 6.2% for highest versus lowest quartile, p=0.019).

Conclusion

HuR expression is associated with early subclinical arterial disease in individuals without clinically overt CVD and with the presence and severity of cardiac and vascular dysfunction in patients with clinically overt CAD. These findings imply a clinical role of the HuR pathway in cardiovascular disease and warrant further investigation.

2228Circulating serum extracellular matrix degradation enzyme cathepsin S predicts mortality and improves risk stratification over the GRACE score in patients with non-ST elevation acute coronary syndrom

Background

Blood-based biomarkers may be useful in the identification of residual risk for death or acute myocardial infarction (AMI) in patients with a previous acute coronary syndrome. Cathepsin S (CTSS) is a lysosomal cysteine protease with potent elastolytic and collagenolytic activity, which plays an important role in cardiovascular disease through extracellular matrix degradation, vasa vasorum development and atherosclerotic plaque rupture. The aim of the present study was to determine the prognostic and reclassification value of baseline circulating levels of CTSS after adjustment for the Global Registry of Acute Coronary Events (GRACE) score, which is widely recommended for risk stratification in non-ST-segment elevation acute coronary syndrome (NSTE-ACS).

Methods

CTSS was measured in blood samples collected from 1,129 consecutive patients with adjudicated NSTE-ACS presenting at an acute chest pain unit for evaluation of a possible acute coronary syndrome. Cardiovascular (CV) death and a composite of all-cause mortality and AMI were evaluated as the primary and secondary endpoints of the study, respectively. The additive prognostic value of CTSS over the GRACE score was estimated by the Net Reclassification Index (NRI) that examines the net upward and downward reclassification into correct pre-defined risk categories.

Results

After a median follow-up of 21 months, 101 (8.95%) deaths were reported, of which 63 (5.6%) were of cardiac origin. The combined endpoint occurred in 176 (15.6%) patients. Patients with CTSS in the highest tertile presented the greatest risk for all-cause mortality (HR=1.84 for highest versus lowest tertile of CTSS distribution, 95% CI 1.1–3.08, P=0.02) and CV death (HR=2.5 for highest versus lowest tertile of CTSS distribution, 95% CI 1.24–5.05, P=0.011) after adjustment for age, gender, diabetes mellitus, hs-cTnT, hsCRP, revascularization and index diagnosis. Similarly, CTSS was associated with increased risk of cardiovascular death after adjusting for the GRACE Score (adjusted HR for highest versus lowest tertile of CTSS distribution=2.34, 95% CI 1.18–4.64, P=0.015). Further, CTSS predicted the combined endpoint of all-cause death or non-fatal MI independently of the GRACE Score (adjusted HR for highest versus lowest tertile of CTSS distribution=1.67, 95% CI 1.15–2.42, P=0.007). When CTSS was added over the GRACE Score, it conferred significant reclassification value for CV death (NRI=21.4%, P=0.008). Similarly, CTSS correctly reclassified risk for all-cause death or non-fatal MI (P=0.006) in 15.9% of the population.

Conclusions

Circulating CTSS predicts mortality and improves risk stratification of patients with NSTE-ACS over the GRACE score recommended by clinical guidelines. The clinical application of CTSS as a novel biomarker in NSTE-ACS should be further explored and validated.

P1732The additive value of pre- and post-reperfusion cardiac troponin T levels in risk stratification of patients with ST-segment elevation myocardial infarction

Background

Despite therapeutic advances, mortality rates following ST-segment elevation myocardial infarction (STEMI) are still alarmingly high. There is conflicting evidence regarding the prognostic role of high-sensitivity cardiac troponin T (hs-cTnT) measurements before and after primary percutaneous coronary intervention (PPCI) over traditional predictors of mortality in STEMI patients.

Purpose

To determine the additive prognostic value of pre- and 12h post-PPCI hs-cTnT levels in STEMI patients

Methods

Retrospective longitudinal study including 3,113 consecutive STEMI patients treated with PPCI at a university hospital covering a population of 1.6 million in the North East of England. Clinical, procedural, and laboratory data were prospectively collected during patient hospitalization while hs-cTnT measurements were performed at admission to the catheterization laboratory and at 12h post-PPCI. Median follow-up was 53 months. The study endpoints were in-hospital and overall mortality. Mortality data were obtained from the UK Office of National Statistics.

Results

Admission hs-cTnT >515ng/L (4th quartile) was independently associated with in-hospital mortality [HR=2.39 per highest to lower quartiles; 95% CI: 1.44 to 3.97; p=0.001] after multivariate adjustment for a core clinical model of in-hospital mortality prediction. Likewise, admission hs-cTnT >515ng/L independently predicted overall mortality (HR=1.25 per highest to lower quartiles; 95% CI: 1.00 to 1.57; p=0.044) after adjustment for covariates significantly associated with this endpoint. Admission hs-cTnT correctly reclassified risk for in-hospital death [net reclassification index (NRI)=44.1%, p<0.001) and overall mortality (NRI=60.4%, p<0.001). Conversely, 12h hs-cTnT was not independently associated with mortality.

Conclusion

Admission, but not 12h post-reperfusion, hs-cTnT predicts mortality and improves risk stratification in the PPCI era. These results support the role of hs-cTnT in risk stratification of post-STEMI patients and challenge the cost-effectiveness of routine 12h hs-cTnT measurements.

Expression of platelet-bound stromal cell-derived factor-1 in patients with non-valvular atrial fibrillation and ischemic heart disease

AIMS

Blood cell infiltration and inflammation are involved in atrial remodelling during atrial fibrillation (AF) although the exact mechanisms of inflammatory cell recruitment remain poorly understood. Platelet-bound stromal cell-derived factor-1 (SDF-1) is increased in cases of ischemic myocardium and regulates recruitment of CXCR4(+) cells on the vascular wall. Whether platelet-bound SDF-1 expression is differentially influenced by non-valvular paroxysmal or permanent atrial fibrillation (AF) in patients with stable angina pectoris (SAP) or acute coronary syndrome (ACS) has not been reported so far.

METHODS AND RESULTS

A total of 1291 consecutive patients with coronary artery disease (CAD) undergoing coronary angiography were recruited. Among the patients with SAP, platelet-bound-SDF-1 is increased in patients with paroxysmal AF compared with SR or to persistent/permanent AF (P < 0.05 for both). Platelet-bound SDF-1 correlated with plasma SDF-1 (r = 0.488, P = 0.013) in patients with AF and ACS, which was more pronounced among patients with persistent AF (r = 0.842, P = 0.009). Plasma SDF-1 was increased in persistent/permanent AF compared with SR. Patients with ACS presented with enhanced platelet-bound-SDF-1 compared with SAP. Interestingly, among patients with ACS, patients with paroxysmal or persistent/permanent AF presented with an impaired platelet-bound SDF-1 expression compared with patients with SR.

CONCLUSIONS

Differential expression of platelet-bound and plasma SDF-1 was observed in patients with AF compared with SR which may be involved in progenitor cell mobilization and inflammatory cell recruitment in patients with AF and ischemic heart disease. Further in vivo studies are required to elucidate the role of SDF-1 in atrial remodeling and the atrial fibrillation course.