Current perspectives on wearable rhythm recordings for clinical decision-making: the wEHRAbles 2 survey.

Novel wearable devices for heart rhythm analysis using either photoplethysmography (PPG) or electrocardiogram (ECG) are in daily clinical practice. This survey aimed to assess impact of these technologies on physicians' clinical decision-making and to define, how data from these devices should be presented and integrated into clinical practice. The online survey included 22 questions, focusing on the diagnosis of atrial fibrillation (AF) based on wearable rhythm device recordings, suitable indications for wearable rhythm devices, data presentation and processing, reimbursement, and future perspectives. A total of 539 respondents {median age 38 [interquartile range (IQR) 34-46] years, 29% female} from 51 countries world-wide completed the survey. Whilst most respondents would diagnose AF (83%), fewer would initiate oral anticoagulation therapy based on a single-lead ECG tracing. Significantly fewer still (27%) would make the diagnosis based on PPG-based tracing. Wearable ECG technology is acceptable for the majority of respondents for screening, diagnostics, monitoring, and follow-up of arrhythmia patients, while respondents were more reluctant to use PPG technology for these indications. Most respondents (74%) would advocate systematic screening for AF using wearable rhythm devices, starting at patients' median age of 60 (IQR 50-65) years. Thirty-six percent of respondents stated that there is no reimbursement for diagnostics involving wearable rhythm devices in their countries. Most respondents (56.4%) believe that costs of wearable rhythm devices should be shared between patients and insurances. Wearable single- or multiple-lead ECG technology is accepted for multiple indications in current clinical practice and triggers AF diagnosis and treatment. The unmet needs that call for action are reimbursement plans and integration of wearable rhythm device data into patient's files and hospital information systems.

Circulating levels of a biomarker of collagen metabolism are associated with health-related quality of life in patients with chronic heart failure.

PURPOSE: Assessment of circulating levels of collagen-derived peptides has been proposed as a useful tool to monitor indirectly myocardial collagen metabolism in chronic heart failure (CHF) patients. The potential link between circulating concentrations of collagen metabolism biomarkers and health-related quality of life (HRQOL) has not been adequately evaluated. With the present study, we investigated the association between serum levels of collagen-derived peptides and HRQOL. METHODS: We studied 280 consecutive outpatients (of mean age 67 ± 10 years, 180 men) with CHF. Serum concentrations of carboxy-terminal telopeptide of collagen type I (CITP)-a marker of collagen type I degradation-were measured in all patients both at baseline and during a period of 6 months follow-up. HRQOL was assessed by Minnesota living with heart failure questionnaire (MLHFQ). RESULTS: CITP levels were significantly associated with MLHFQ scores both at baseline (r = 0.231, P < 0.001) and at 6 months follow-up (r = 0.145, P = 0.044). CITP levels remained significantly associated with MLHFQ score in multivariable linear regression analysis. Higher CITP levels were observed with higher MLHFQ scores (poor HRQOL) both at baseline (P = 0.001) and at 6 months (P = 0.041). Unadjusted analysis demonstrated a significant relationship between increasing CITP levels during 6 months follow-up and worsening HRQOL (r = 0.204, P = 0.001). The aforementioned correlation remained significant in multivariable linear regression analysis. CONCLUSION: Our findings show that increased CITP levels are associated with poorer HRQOL in patients with CHF. These findings are consistent with a link between a pathophysiologic mechanism, i.e., collagen metabolism and patient self-assessed health status in CHF.

The industrialization of ablation: a highly standardized and reproducible workflow for radiofrequency ablation of atrial fibrillation.

BACKGROUND OR PURPOSE: The purpose of this analysis was to report on efficacy of a standardized workflow for atrial fibrillation (AF) ablation using technology advances such as 3D imaging and contact force sensing in a real-world setting. METHODS: Consecutive AF ablations from 2014 to 2015 at a high-volume site in Belgium were included. The workflow consisted of a pre-specified procedure sequence including 3D modeling followed by radiofrequency encircling of the pulmonary veins (25 W posterior wall, 35 W anterior wall) with a THERMOCOOL SMARTTOUCH® Catheter guided by CARTO VISITAG™ Module (2.5 mm/5 s stability, 50% > 7 g) and ablation index (targets: 550 anterior wall, 400 posterior wall). Efficiency endpoints were procedure time, fluoroscopy time, and radiation dose. The primary effectiveness endpoint was freedom from atrial arrhythmia recurrence. RESULTS: A total of 605 paroxysmal AF (PAF) and 182 persistent AF (PsAF) patients were followed for 436 ± 199 days. Mean procedure times were short (PAF: 96.1 ± 26.2 min; PsAF: 109.2 ± 35.6 min) with most procedures (90.6% PAF; 81.3% PsAF) completed in ≤ 120 min. Minimal fluoroscopy was utilized (PAF: 6.1 ± 3.8 min, 5.9 ± 3.4 Gy*cm2; PsAF: 6.9 ± 4.7 min, 7.4 ± 4.9 Gy*cm2). Freedom from atrial arrhythmia recurrence was higher for PAF than PsAF patients (OR: 2.0, 95% CI: 1.4-2.9, p = 0.0003), but adjusted mean rates were high in both groups (81.0% vs. 67.9%). Rates were adjusted for prior ablation and age (at 65 years). CONCLUSION: AF ablation using a standardized workflow resulted in low procedure times and variability, with minimal fluoroscopy exposure. Long-term freedom from atrial arrhythmia recurrence was high in both PAF and PsAF populations.

Statin use is associated with a significant reduction in cholesterol content of erythrocyte membranes. A novel pleiotropic effect?

PURPOSE: High cholesterol content of erythrocyte membranes (CEM) levels is present in patients with acute coronary syndromes (ACS). Intraplaque hemorrhage and erythrocyte lysis contribute to the deposition of cholesterol on the atherosclerotic plaque and to plaque rupture. With the present study we assessed the effect of statin therapy on CEM levels, a novel marker of coronary artery disease (CAD) instability during a 1-year follow-up in CAD patients. METHODS: 212 consecutive eligible (158 men, 62 +/- 10 years) patients undergoing diagnostic coronary angiography for the assessment of angina pectoris were assessed. The study population comprised of 84 chronic stable angina (CSA) patients and 128 ACS patients. All study participants were commenced on statin treatment in equipotent doses and were followed for up to 1 year (at - 1, - 3, - 6 and - 12 months). RESULTS: Repeated measurements analysis of variance after appropriate adjustment showed a significant decrease (p < 0.001) in CEM content during follow up. CEM levels were decreasing at each time point (1 month : 100 microg/mg 95%CI 94.3-105.6, 3 months : 78.1 microg/mg 95%CI 73.2-83, 6 months : 67.2 microg/mg 95%CI 63.1-71.2, 1 year : 45.3 microg/mg 95%CI 42.2-48.3) compared to admission (112.1 microg/mg 95% CI 105.9-118.3) and to all previous measurements. CONCLUSIONS: The present study showed, that use of statins is associated with a reduction in CEM, an emerging marker of clinical instability and plaque vulnerability in CAD patients. The pleiotropic effects of statins at the cell membrane level represent a promising novel direction for research in CAD.

Interleukin-8 is increased in the membrane of circulating erythrocytes in patients with acute coronary syndrome.

AIMS: Studies have shown that erythrocyte membranes are present within necrotic cores in atherosclerotic plaques, and that circulating erythrocytes in patients with acute coronary syndrome (ACS) have increased total cholesterol content (CEM). Interleukin-8 (IL-8) binds to erythrocytes and during intraplaque haemorrhage it is released into the plaque and thus may contribute to inflammatory cascade and atherosclerotic plaque instability. The present study was undertaken to test the hypothesis that erythrocyte membrane IL-8 is elevated in patients with ACS compared with those with chronic stable angina (CSA). METHODS AND RESULTS: Consecutive patients who presented with CSA (n = 120, 92 men, 62 +/- 9 years), ACS (n = 118, 90 men, 62 +/- 10 years) or with chest pain who had normal coronary arteries (n = 36, 26 men, 60 +/- 7 years), were studied prospectively. IL-8 concentrations in erythrocyte membranes (rIL-8) and in plasma (pIL-8), C-reactive protein (CRP) and CEM were measured. rIL-8 levels [mean +/- 1 SD (standard deviation)] were higher in ACS (102.9 +/- 70.1 pg/mL) compared with CSA (44.7 +/- 22.8 pg/mL) (P < 0.001). No difference in pIL-8 levels between the two coronary artery disease groups was observed (P = 0.280). Serum CRP levels were correlated with rIL-8 levels (r = 0.294, P < 0.001); no association was found between CRP and pIL-8 levels (r = 0.025, P = 0.706). Further, rIL-8 had an independent association with ACS, when CRP and CEM were taken into consideration. CONCLUSION: This study shows for the first time that rIL-8 content was significantly higher in ACS, compared with CSA. These findings endorse results from our previous studies suggesting that erythrocytes may play an important role in the development of unstable atherosclerotic plaque.

Resolution of symptoms and serum peptides of collagen type I turnover in acute heart failure patients.

OBJECTIVES: Myocardial collagen content as a fundamental component of extracellular matrix, is altered in pathological states including heart failure (HF). Serum peptides related to myocardial collagen synthesis and degregation can be measured and may be used as indices of myocardial collagen turnover. The present study was undertaken to assess the hypothesis that resolution of acute decompensation of chronic HF is associated with changes in serum peptides related to collagen synthesis and degregation. METHODS AND RESULTS: Serum concentrations of the amino-terminal propetide of procollagen type I (PINP) and the carboxy-terminal telopeptide of collagen type I (CITP), indices of collagen type I synthesis and degradation, respectively, were determined at the time of admission and discharge in 156 patients (100 men, 68 +/- 10 years) with acute decompensation of chronic HF. A significant decrease (-3.5 ng/ml 95% CI -5.3/-1.6 ng/ml, P < 0.001) of PINP was observed whereas CITP levels were significantly increased (+ 0.04 ng/ml 95% CI 0.01-0.08 ng/ml, P = 0.031) at discharge compared to admission. CONCLUSIONS: Findings of the present study showed that serum indices of myocardial collagen turnover were changed significantly in a short period of time during the improvement of acute decompensation of chronic HF.

Long-term impact of acute kidney injury on prognosis in patients with acute myocardial infarction.

BACKGROUND: Little evidence exists regarding the long-term impact of acute kidney injury (AKI) during index hospitalisation for acute myocardial infarction (AMI). We prospectively assessed the long-term prognostic significance of the occurrence of in-hospital AKI in a multicentre cohort of patients admitted with AMI. METHODS: Data were obtained from 518 AMI patients with a median follow-up of 5.6 (IQR 4.6-6.5) years. Patients were followed up regarding the occurrence of death, major adverse cardiovascular events (MACE), and any deterioration in kidney function. RESULTS: From the study cohort, 84 patients (16%) had developed AKI at discharge during index hospitalisation. 96 patients died during follow-up, MACE occurred in 90 patients, and 30 patients showed evidence of deterioration in kidney function. Patients with AKI at hospital discharge had a three-fold increased mortality risk (HR 3.2, 95% CI 2.1-4.8; P < 0.001). This association was independent of possible confounding by variables that could influence prognosis (HR 1.9 95% CI 1.1-3.2; P = 0.028) evident only up to three years during follow-up. During long-term follow-up, patients with AKI during their index hospitalisation had a significantly (P = 0.027) higher incidence of MACE (26%) than those who did not develop AKI (15%). Patients with AKI had a higher incidence of deteriorating kidney function (10%) than those without AKI (5%) during follow-up, but this difference was not significant (P = 0.124). CONCLUSIONS: Our findings emphasise in addition to the need for appropriate long term follow-up in such patients, an increased mortality and morbidity during the first three years after the index event.

Effect of statins on collagen type I degradation in patients with coronary artery disease and atrial fibrillation.

The present study was undertaken to assess the effect of statins on collagen type I degradation and C-reactive protein in patients with coronary artery disease and atrial fibrillation. One hundred six patients with coronary artery disease and atrial fibrillation were studied: 40 (36 men, mean age 72 +/- 8 years) treated with a statin and 66 (48 men, mean age 74 +/- 9 years) not treated with a statin. Serum concentrations of carboxy-terminal telopeptide of collagen type I, an index of collagen type I degradation, and high-sensitivity C-reactive protein were measured in all patients. Carboxy-terminal telopeptide of collagen type I levels were significantly higher (p <0.001) in statin-treated patients (0.64 ng/ml, 95% confidence interval [CI] 0.57 to 0.71) compared with nonstatin-treated patients (0.38 ng/ml, 95% CI 0.31 to 0.44). These changes were independent of cholesterol levels (before or after therapy). Statin-treated patients had significantly lower (p <0.001) C-reactive protein levels (0.25 mg/dl, 95% CI 0.23 to 0.28) compared to statin nonusers (1.1 mg/dl, 95% CI 0.92 to 1.25). In conclusion, this study suggests that therapy with statins in patients with coronary artery disease and atrial fibrillation is associated with an increase in collagen degradation and an attenuation of inflammation, independently of cholesterol lowering.

Serum levels of collagen type-I degradation markers are associated with vascular stiffness in chronic heart failure patients.

BACKGROUND: Chronic heart failure (CHF) induces peripheral vasoconstriction, endothelial dysfunction and arterial stiffness by activation of various neurohormonal pathways. The abnormal collagen turnover observed in CHF may be attributed not only to myocardial remodelling, but also to vascular remodelling. However, the effect of collagen metabolism on progressive large artery stiffening in the setting of CHF is understudied. AIMS: The present study was undertaken to investigate the association between circulating markers of collagen turnover and vascular stiffness in patients with CHF. METHODS: Eighty patients (mean age 65+/-11 years, 68 men) with stable CHF and in sinus rhythm, were studied. Serum concentrations of carboxy-terminal telopeptide of collagen type I (CITP) and amino-terminal propetide of procollagen type I (PINP), markers of collagen type I degregation and synthesis respectively, were measured in all patients. Pulse wave velocity (PWV) and augmentation index (AIx) of aortic pulse wave form, markers of arterial stiffness, were also determined by applanation tonometry. RESULTS: Peripheral PWV was inversely associated with serum CITP levels (r=-0.585, p<0.001). AIx although weakly was negatively correlated with serum CITP levels (r=-0.285, p=0.01). Multiple regression analysis showed that peripheral PWV remained independently associated with serum CITP levels after adjustment for all confounding variables. CONCLUSIONS: Findings from the present study imply a possible link between altered collagen metabolism and peripheral vascular stiffness in CHF.

Left atrial volume computed by 3D rotational angiography best predicts atrial fibrillation recurrence after circumferential pulmonary vein isolation.

Left atrium (LA) size is a well-studied predictor of atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI). Yet, there is still little agreement on the best imaging technique to size the LA, and on the most appropriate sizing parameter. Volumetric assessment of LA with three-dimensional rotational angiography (3DRA LA volume index) might be a valid alternative to the commonly used transthoracic echocardiography (TTE LA volume index). The aim of our study was to investigate whether LA volume by 3DRA at the time of PVI is able to predict the risk of atrial fibrillation recurrence. We analysed 352 consecutive patients with symptomatic paroxysmal or persistent atrial fibrillation referred for PVI to our Institution. In all patients, LA volume index (LAVI) was assessed by TTE and by 3DRA. Sinus rhythm was restored after PVI in 348 patients (99%). Average TTE-LAVI and 3DRA-LAVI were 37 ± 12 and 83 ± 18 ml/m2, respectively. At a median follow-up of 19 (12, 24) months, 27% of patients had AF recurrence after the first PVI. At the univariate analysis, persistent AF (p < 0.01), use of anti-arrhythmic drugs (AAD) (p < 0.05) and 3DRA-LAVI (p < 0.01) were significantly associated with AF recurrence. In contrast, none of the echocardiographic parameters considered, including TTE-LAVI, was associated with AF recurrence (p = 0.29). At the multivariate analysis, 3DRA-LAVI was the only independent predictor for AF recurrence (HR 1.01 [1.00-1.03], p = 0.017). Left atrial volume measured with 3DRA is superior to TTE assessment and to AF history in predicting atrial fibrillation recurrence after PVI.

Osteopontin in relation to Prognosis following Coronary Artery Bypass Graft Surgery.

Cardiovascular events may occur even after complete revascularization in patients with coronary artery disease. We measured preoperative osteopontin (OPN) levels in 131 consecutive patients (66.5 ± 10 years old, 117 men and 14 women) with left ventricular ejection fraction of 50.7 ± 9.2% and low logistic EuroScore (3.5 ± 3.2%) undergoing elective Coronary Artery Bypass Grafting (CABG) surgery. Patients were prospectively followed up for a median of 12 months (range 11-24). The primary study endpoint was the composite of cardiovascular death, nonfatal myocardial infarction, need for repeat revascularization, and hospitalization for cardiovascular events. Pre-op OPN plasma levels were 77.9 (49.5, 150.9). Patients with prior acute myocardial infarction (AMI) had significantly higher OPN levels compared to those without [131.5 (52.2, 219) versus 73.3 (45.1, 125), p = 0.007]. OPN levels were positively related to EuroScore (r = 0.2, p = 0.031). Pre-op OPN levels did not differ between patients who had a major adverse event during follow-up compared to those with no event (p = 0.209) and had no effect on the hazard of future adverse cardiac events [HR (95% CI): 1.48 (0.43-4.99), p = 0.527]. The history of AMI was associated with increased risk of subsequent cardiovascular events at follow-up (p = 0.02). OPN is associated with preoperative risk assessment prior to low-risk CABG but did not independently predict outcome.

Spot urine albumin to creatinine ratio outperforms novel acute kidney injury biomarkers in patients with acute myocardial infarction.

BACKGROUND: Acute kidney injury (AKI) is a frequent complication in patients hospitalized for acute myocardial infarction (AMI), and is associated with in-hospital and long-term morbidity and mortality. We prospectively assessed the diagnostic performance of spot urine albumin to creatinine ratio (uACR) in an adequately sized multicenter cohort of patients admitted to hospital with AMI. We further compared uACR to novel renal injury associated biomarkers regarding their diagnostic ability. METHODS: We enrolled 805 consecutive patients presenting with acute ST-elevation and non-ST elevation AMI. Patients were assessed for presence of AKI at 48h post-admission and at hospital discharge using the Acute Kidney Injury Network (AKIN), the Acute Dialysis Quality Initiative [Risk, Injury and Failure (RIFLE)] criteria and the Kidney Disease: Improving Global Outcomes (KDIGO) criteria. Blood and urine sampling for neutrophil gelatinase-associated lipocalin (NGAL), interleukin-18 (IL-18), cystatin-C, and uACR assessment was performed during admission. RESULTS: The predictive accuracy of uACR was good (Area Under the Curve (AUC), 0.725; 95% CI 0.676-0.774) and was better compared to urine NGAL (P=0.007), urine (P<0.001) and plasma Cystatin-C (P=0.001). ROC analysis identified concentrations of ≥66.7µg/mg as having the best diagnostic accuracy. The use of uACR exhibited good discriminating ability independent to possible cofounders and additive regarding the use of novel biomarkers. CONCLUSIONS: The use of uACR can easily be applied in the clinical setting, allows for robust risk assessment and offers the potential to improve the management of AMI patients at risk for acute kidney injury.

Validation of a new risk score to predict contrast-induced nephropathy after percutaneous coronary intervention.

Contrast-induced nephropathy (CIN) is a frequent, potentially lethal complication of percutaneous coronary interventions (PCIs). We prospectively validated the diagnostic performance of a simple CIN risk score in a large multicenter international cohort of patients who underwent PCI. About 2,882 consecutive patients treated with elective or urgent PCI were enrolled. A simple CIN risk score was calculated for all patients by allocating points according to a prespecified scale (pre-existing renal disease = 2; metformin use = 2; previous PCI = 1; peripheral arterial disease = 2; and injected volume of contrast medium ≥300 ml = 1). CIN was defined as an increase, compared with baseline, of serum creatinine by ≥25%, or by ≥0.5 mg/dl, 48 hours after PCI. CIN occurred in 15.7% of the study population. The predictive accuracy of the CIN risk score was good (c-statistic 0.741, 95% confidence interval 0.713 to 0.769). Receiver-operating characteristic analysis identified a score of ≥3 as having the best diagnostic accuracy. Examination of the performance of the proposed risk score using different definitions of CIN yielded a robust predictive ability. The score exhibited good discrimination (area under the curve ≥0.700) across all predefined subgroups of the study population. Compared with 2 previously published risk scores for CIN, our score demonstrated higher discriminative ability and resulted in a net reclassification improvement and an integrated discrimination improvement (p <0.001). In conclusion, the new risk score can easily be applied in the setting of urgent or elective PCI, allows for robust risk assessment and offers the potential to improve the peri-interventional management of patients at risk for CIN.

Independent and additive prognostic ability of serum carboxy-terminal telopeptide of collagen type-I in heart failure patients: a multi-marker approach with high-negative predictive value to rule out long-term adverse events.

BACKGROUND: Altered myocardial extracellular matrix turnover has been proposed as a major determinant of myocardial remodelling. Carboxy-terminal telopeptide of collagen type-I (CITP) represents a collagen type-I degradation-derived serum peptide. In this study we examined the independent and additive prognostic value of serum concentrations of CITP compared with well-known mortality predictors such as the N-terminal pro-brain natriuretic peptide (NT-proBNP) in chronic heart failure (CHF) patients. METHODS: We studied 196 consecutive patients (126 male, mean age 69 ± 10 years), who were admitted for acute decompensation of the CHF syndrome. The study entry point was determined at the discharge of the patients after achieving a stable compensated status. The primary endpoint was cardiac mortality during a 12-month follow-up. RESULTS: In the multivariate Cox proportional hazard model the levels of CITP remained a predictor of survival (hazards ratio 0.4 95% confidence interval 0.21-0.76, P = 0.005), independent of NT-proBNP levels. The stratified log-rank test (P < 0.001) showed that CHF patients characterized by low levels of both biomarkers had better survival (hazards ratio 0.12 95% confidence interval 0.04-0.35, P < 0.001) compared with patients characterized by high levels of both biomarkers. The negative predictive value of the combined measure for long-term adverse events was 94%. CONCLUSION: Serum levels of CITP were shown to be an independent and strong prognostic marker regarding survival in CHF patients. Furthermore, CITP levels had an additive prognostic value compared with NT-proBNP levels. These findings underline the detrimental role of myocardial fibrosis in the progression of heart failure and suggest a novel multi-marker approach for risk stratification in the CHF syndrome.

Chronic heart failure patients with high collagen type I degradation marker levels benefit more with ACE-inhibitor therapy.

Not all patients respond to angiotensin converting enzyme (ACE)-inhibitor equally. Genetic or other phenotypic variations might be useful in predicting the therapeutic efficacy of these drugs. With the present study we assessed the prognostic impact of ACE-inhibitor in chronic heart failure patients with different degrees of collagen metabolism as assessed by serum levels of a collagen type I degradation marker (CITP). One hundred ninety-six (126 male, 69+/-10 years) chronic heart failure patients were studied prospectively for 12 months regarding survival. Serum concentrations of CITP were measured at study entry. Chronic heart failure patients were divided into groups according to whether (n=114) or not (n=82) they received ACE-inhibitor as well as to their CITP levels. Survival (52.2%) was significantly lower in ACE-inhibitor naive patients with high CITP levels compared to ACE-inhibitor naive patients with low CITP levels (83.3%, P=0.003), to ACE-inhibitor users with low CITP levels (80%, P=0.006) and to ACE-inhibitor users with high CITP levels (70.4%, P=0.015). ACE-inhibitor related improvement in mortality was most predominant in chronic heart failure patients with high CITP levels. CITP levels possibly reflecting an activated status of the renin-angiotensin-aldosterone system, may be of clinical relevance since they identify a subgroup of patients that is more susceptible to treatment with an ACE-inhibitor.

Cholesterol composition of erythrocyte membranes and its association with clinical presentation of coronary artery disease.

OBJECTIVES: Presence of free cholesterol in atherosclerotic plaques is a major determinant of plaque instability. It is hypothesized that extravasated erythrocytes may contribute to free cholesterol accumulation in atherosclerotic plaques through their rich in cholesterol membrane. In this study we assessed whether cholesterol in erythrocyte membranes (CEMs), that is, free (FCEM) versus esterified (ECEM), differs in patients with chronic stable angina (CSA) compared with patients presenting with acute coronary syndromes (ACSs). METHODS: Consecutive angina patients were prospectively assessed; 154 had CSA (118 men, 63 years, 56-69 years) and 164 ACS (124 men, 63 years, 55-71 years). FCEM and ECEM were measured using an enzymatic assay, and protein content was assessed by the Bradford method. RESULTS: FCEM was significantly higher (P<0.001) in the ACS patients group (94.1 microg/mg, IQ 71-116.5 microg/mg) compared with patients with CSA (61.9 microg/mg, IQ 49.3-73.1 microg/mg). ECEM levels were also significantly higher (P<0.001) in ACS patients (23.3 microg/mg, IQ 14.9-47.7 microg/mg) compared with CSA patients (10.8 microg/mg, IQ 8-22.3 microg/mg). In contrast, ratio of free-to-esterified cholesterol (P=0.110) as well as ratio of free-to-total CEM (P=0.109) were not different among CSA and ACS patients. CONCLUSION: Findings of this study show that although free cholesterol is the prevailing form of CEMs, both FCEM and ECEM levels are increased in patients with ACS compared with CSA patients. These findings suggest that it is the quantity of CEM rather than the type of cholesterol present in the erythrocyte membrane that determines plaque progression.