High-Sensitivity Troponin I and Cardiovascular Events in Stable Coronary Artery Disease: Insights from a Longitudinal Outpatient Study

Numerous studies have been published suggesting that troponin levels are related to adverse outcomes in chronic cardiac and non-cardiac conditions. Our study investigated whether troponin levels gathered from unselected blood samples taken during outpatient care are associated with adverse outcomes in a population with stable coronary artery disease. In a cohort of 949 patients with stable coronary artery disease, an average age of 67.5 ± 9.5 years, 69.5% male, 52.1% diabetics, 51.6% with previous myocardial infarction, and 57.9% with triple-vessel disease, 21.7% of patients encountered new events during an average period of monitoring of 2.07 ± 0.81 years. Troponin I/99th percentile categorized into tertiles emerged as an independent predictor of death and combined events risk (hazard ratio: 2.02 (1.13-3.60), p = 0.017; 2.30 (1.37-3.88, p = 0.002, respectively). A troponin ratio > 0.24 was able to identify 53.3% of patients at risk of death and heart failure hospitalization. In patients with stable coronary artery disease who are adherent to treatment, troponin levels are independently associated with death and heart failure hospitalization in a medium-term follow-up.

Chronic troponin elevation assessed by myocardial T1 mapping in patients with stable coronary artery disease

BACKGROUND

Cardiac troponin detected with sensitive assays can be chronically elevated, in the absence of unstable coronary syndromes. In patients with chronic coronary artery disease, clinically silent ischemic episodes may cause chronic troponin release. T1 mapping is a cardiovascular magnetic resonance technique useful in quantitative cardiac tissue characterization. We selected patients with anatomically and functionally normal hearts to investigate associations between chronic troponin release and myocardial tissue characteristics assessed by T1 mapping.

METHODS

We investigated the relationship between cardiac troponin I concentrations and cardiovascular magnetic resonance T1 mapping parameters in patients with stable coronary artery disease enrolled in MASS V study before elective revascularization. Participants had no previous myocardial infarction, negative late gadolinium enhancement, normal left ventricular function, chamber dimensions and wall thickness.

RESULTS

A total of 56 patients were analyzed in troponin tertiles: nativeT1 and extracellular volume (ECV) values (expressed as means ± standard deviations) increased across tertiles: nativeT1 (1006 ± 27 ms vs 1016 ± 27 ms vs 1034 ± 37 ms, ptrend = 0.006) and ECV (22 ± 3% vs 23 ± 1.9% vs 25 ± 3%, ptrend = 0.007). Cardiac troponin I concentrations correlated with native T1(R = 0.33, P = .012) and ECV (R = 0.3, P = .025), and were independently associated with nativeT1 (P = .049) and ventricular mass index (P = .041) in multivariable analysis.

CONCLUSION

In patients with chronic coronary artery disease and structurally normal hearts, troponin I concentrations correlated with T1 mapping parameters, suggesting that diffuse edema or fibrosis scattered in normal myocardium might be associated with chronic troponin release.

Evaluation of cardiovascular risk biomarkers after moderate consumption of red wine and cachaça in a randomized crossover trial: The Wine and Cachaça Study (WICAS)

INTRODUCTION

Moderate daily consumption of alcohol (MDCA) is associated with cardiovascular risk (CVR) reduction in observational studies. Some researches have suggested that this benefit may be associated not only with red wine consumption but also with other beverages. However, there are no clinical trials evaluating the possible CVR benefit of Brazilian spirit (cachaça) in humans.

METHODS

This is a prospective, randomized, crossover study including healthy individuals initially assigned to a MDCA of cachaça or red wine for a period of 4 weeks. After a one-week abstinence period, the type of drink was changed for another 4 weeks of intervention. The MDCA for both beverages was determined as a dose equivalent to 28 g of ethanol per day for men and 14 g for women. CVR biomarkers analyses were performed before and after each intervention to assess the serologic status of C-reactive protein, lipid profile, platelet aggregation and glycemic profile. This study is registered on the ISRCTN platform under number 15978506.

RESULTS

Of the 42 subjects initially randomized, 2 refused to continue in the study. The median age was 44.3 ± 10.3 years and 19 were male (47.5%). Adherence to the protocol was considered ideal with 100% regular use in both interventions and only 3 individuals in each intervention group reported alcohol abuse. There was no significant variation in anthropometric measurements during the study, except for weight gain (0.7 kg) in the red wine group (p = 0.005). The median of the delta of platelet aggregation for MDCA of cachaça was 1.2% (-1.1 to 5.3) and the median of the delta to the MDCA of wine was -1.6% (-4.5 to 2) (p = 0.02). The other biomarkers didn't show any statistically significant variation.

CONCLUSION

Moderate consumption of wine and cachaça was related to variation in laboratory biomarkers of CVR related to atherosclerosis. There was significant weight gain during the period of wine consumption and there was observed a difference between platelet aggregation values after both interventions.

Nicotinamide attenuates streptozotocin-induced diabetes complications and increases survival rate in rats: role of autonomic nervous system

BACKGROUND

To evaluate the effect of nicotinamide prior to streptozotocin-induced (STZ) diabetes in baroreflex sensitivity and cardiovascular autonomic modulation, and its association with hemodynamics and metabolic parameters.

METHODS

Methods: Male Wistar rats were divided into control (Cont) and STZ-induced diabetes (Diab). Half of the rats from each group received a single dose of nicotinamide (100 mg/Kg) before STZ injection (Cont+NicA and Diab+NicA). All groups were followed-up for 5 weeks.

RESULTS

Body weight loss of more than 40% was observed in Diab throughout the period (Diab: 271.00 ± 12.74 g; Diab+NicA: 344.62 ± 17.82). Increased glycemia was seen in Diab rats (541.28 ± 18.68 mg/dl) while Diab+NicA group had a slight decrease (440.87 ± 20.96 mg/dl). However, insulin resistance was observed only in Diab. In relation to Cont, heart rate, mean blood pressure and diastolic function were reduced when compared to Diab, together with parasympathetic modulation and baroreflex sensitivity. All of these parameters were improved in Diab+NicA when compared to Diab. Improved baroreflex sensitivity and parasympathetic modulation were correlated with glycemia, insulin resistance, and body weight mass. Additionally, Diab+NicA group increased survival rate.

CONCLUSIONS

Results suggest that the association of nicotinamide in STZ-induced diabetic rats prevents most of the expected derangements mainly by preserving parasympathetic and baroreflex parameters.

Blood cell adhesion to arterial filters analysis by scanning electron microscopy and real-time PCR assay: observational clinical study in cardiac surgery patients

INTRODUCTION

Arterial filter is the part of the cardiopulmonary bypass circuit where blood cells are exposed to high mechanical stress and where cellular aggregates may fasten in large quantities. The aim of this study was to analyse blood cell adhesiveness in the arterial filter through scanning electron microscopy and real-time PCR assay.

METHODS

Prospective, clinical and observational study performed on 28 patients undergoing cardiac surgery with cardiopulmonary bypass. Arterial filters were analysed by scanning electron microscopy. Real-time PCR assay was performed in extracted material from the arterial filters for analysis of platelet GPIb and CD45 leucocyte gene expression. Blood coagulation was analysed during cardiopulmonary bypass. Patients were followed until hospital discharge or 28 days after surgery.

RESULTS

All studied arterial filters used in the subject patients showed a degree of adhesion from blood elements at scanning electron microscopy. All studied filters were positive for platelets GPIb gene expression and 15% had CD45 leucocyte gene expression. The GPIb platelet gene expression in blood lowered at the end of cardiopulmonary bypass (p = 0.019). There was negative correlation between blood GPIb platelet gene expression and Clot SR (HEPSCREEN2 ReoRox^®) (rho = 0.635; p = 0.027). The filter fields count was correlated to the D-dimer dosage (rho = 0.828; p < 0.001).

CONCLUSION

There was adhesion of blood elements, especially nucleated platelets, on all arterial filters studied. Although the arterial filter worked as a safety device, that possibly prevented arterial embolisation, it may also have caused greater hyperfibrinolysis during cardiopulmonary bypass.

Evaluation of the Long-Term Impact on Quality After the End of Pharmacist-Driven Warfarin Therapy Management in Patients With Poor Quality of Anticoagulation Therapy

Background

Warfarin is the most common oral anticoagulant drug, especially in low-income and emerging countries, because of the high cost of direct oral anticoagulant (DOACs), or when warfarin is the only proven therapy (mechanical prosthetic valve and kidney dysfunction). The quality of warfarin therapy is directly associated with dose management. Evidence shows that pharmaceutical care achieves a better quality of therapy with warfarin. However, there are no studies showing this intervention in a specific patient group with poor quality of anticoagulation in a long period after the end of the follow-up by a pharmacist. Thus, the aim of this study was to evaluate whether the quality of warfarin therapy driven by a pharmacist remains stable in the long term after the end of follow up with a pharmacist, in AF patients with poor quality of anticoagulation.

Methods

This is a prospective study, which evaluated about 2,620 patients and selected 262 patients with AF and poor quality of anticoagulation therapy with warfarin (TTR<50% - based on the last three values of international normalized ratio). Pharmacist-driven therapy management was performed up to 12 weeks. Data from patients were evaluated 1 year after the end of the follow-up with pharmacist.

Results

Comparison between mean TTR after 12 weeks of pharmaceutical care (54.1%) and mean TTR one year after the end of the pharmaceutical care (56.5%; p=0.081) did not achieve statistical difference, demonstrating that the increment of quality due to intervention of 12 weeks was maintained for 1 year after intervention.

Conclusion

The long-term impact of pharmaceutical care was beneficial for patients with AF and poor quality of warfarin anticoagulation. This design might be an important strategy to treat a subgroup of patients without proven effectiveness of warfarin.

Significant association of SYNTAX score on release of cardiac biomarkers in uncomplicated post-revascularization procedures among patients with stable multivessel disease: MASS-V Study group

This study investigated the relationship between angiographic complexities of coronary artery disease (CAD) assessed by SYNTAX Score synergy between percutaneous coronary intervention with taxus and cardiac surgery score (SYNTAX Score) and cardiac biomarker elevation after revascularization procedures.This is a post-hoc analysis of the medicine, angioplasty or surgery study V study of patients with stable CAD. High-sensitivity troponin 1 (hs-TnI) and creatinine kinase-muscle/brain (CK-MB) were assessed before and after cardiovascular procedures. Baselines SYNTAX Scores (SXScores) were calculated by blinded investigators to patient characteristics.Of the 202 patients studied, the mean SXScore was 21.25 ± 9.24; 40.10 ± 7.09 in the high SXScore group and 19.06 ± 6.61 in low/mid SXscore group (P < .0001). Positive correlations existed between SXScore and median peaks after procedural hs-TnI (r = 0.18, P = .009) and CK-MB (r = 0.24, P = .001) levels. In patients with high SXScores (≥33), the median peaks of post-procedural hs-TnI (P = .034)and CK-MB (P = .004) levels were higher than in low/mid SXScore group (<33).The release of hs-TnI at 6 (P = .002), 12 (P = .008), and 24 hours (P = .039) was higher in high SXScore group than in low/mid SXscore group (<33) as was the release of CK-MB at 6 (P < .0001), 12 (P < .0001), 24 (P = .001), 36 (P = .007), 48 (P = .008), and 72 hours (P = .023). After multivariable analysis, high SXScore was a significant independent predictor of release of CK-MB and hs-TnI peaks higher than the median.The increase in release of cardiac biomarkers was significantly associated with the extent of atherosclerosis identified by the SYNTAX Score.

P4681Early findings in patients with noncompaction cardiomyopathy and normal ejection fraction: a cardiopulmonary exercise test, echocardiographic and biomarkers study

Background

Noncompaction cardiomyopathy (NCC) is a cardiomyopathy with controversial diagnostic criteria. Furthermore, it has been discussed whether asymptomatic individuals with normal left ventricular (LV) ejection fraction (EF) and diagnostic criteria for this disease could be classified as NCC. Therefore, the objective of this study was to evaluate the functional capacity of patients with NCC and the relation with echocardiographic and biomarkers indices.

Methods

Fifty-nine patients with NCC were prospectively divided into three groups: ejection fraction (EF)>50% (G1), EF between 40 - 50% (G2) and EF <40% (G3). In addition, 11 normal healthy volunteers were selected for control group (CG). All subjects underwent 2D echocardiography with tissue Doppler and myocardial deformation indices, cardiopulmonary exercise test (CPET), troponin I and BNP measurements.

Results

There was a decrease in VO2 peak (ml/km/min) in all NCC groups compared to CG (GC= 34.5±5.3, G1= 25.56±5.6, G2= 25.12±7.7 and G3= 21.86±6.3 ml/kg/min, p<0.001), but no difference was shown among NCC patients (p=0.37). In addition, the VO2 at anaerobic threshold (AT) was lower in all NCC groups compared to CG (GC= 22.88±3.3, G1= 17.30±4.7, G2= 18.58±5.2, e G3= 15.65±3.7 ml/kg/min, p<0.001). There was an increase in indexed ventricular mass in all NCC groups when compared to CG (p<0.001), but it was similar among NCC groups (p=0.72). Regarding to diastolic function, G2 and G3 presented a reduction in the peak velocity of the septal E' when compared to the control group (GC= 14.0±2.4, G2= 8.92±3.0 e G3= 6.86±3.9 cm/s, p<0,001), while E/E' was increased in G3 compared to all groups (p<0.001). G2 and G3 presented a decrease in global longitudinal strain (GLS) when compared to CG and G1 (p<0.001). The BNP levels were higher in G3 compared to the other groups (p<0.05), but no difference was found in troponin I levels. There was a positive correlation between VO2 peak and E' (r=0.56, p<0.001) and a negative correlation between VO2 peak and E/E' (r=−0.53, p<0.001). In addition, there was an inverse correlation between VO2 peak and BNP (r=−0.50, p<0.001).

Conclusion

Our results show that NCC patients present alterations in functional capacity, echocardiographic indices and biomarkers values according to LV dysfunction. Moreover, patients with preserved LV function already present predominant alterations in CPET suggesting subclinical myocardial dysfunction. For this reason, clinical treatment could be considered in this initial stage of this disease.

Pharmaceutical Care Increases Time in Therapeutic Range of Patients With Poor Quality of Anticoagulation With Warfarin

Thromboembolic events are associated with high mortality and morbidity indexes. In this context, warfarin is the most widely prescribed oral anticoagulant agent for preventing and treating these events. This medication has a narrow therapeutic range and, consequently, patients usually have difficulty in achieving and maintaining stable target therapeutics. Some studies on the literature about oral anticoagulant management showed that pharmacists could improve the efficiency of anticoagulant therapy. However, the majority of these studies included general patients retrospectively. The aim of this study was to prospectively evaluate a pharmacist’s warfarin management in patients with poor quality of anticoagulation therapy (Time in the Therapeutic Range- TTR < 50%). We included 268 patients with atrial fibrillation (AF) and without stable dose of warfarin (TTR < 50%, based on the last three values of International Normalized Ratio-INR). We followed them up for 12 weeks, INR values were evaluated and, when necessary, the dose adjustments were performed. During the first four visits, patient’s INR was measured every 7 days. Then, if INR was within the target therapeutic range (INR: 2–3), the patient was asked to return in 30 days. However, if INR was out the therapeutic target, the patient was asked to return in 7 days. Adherence evaluation was measured through questionnaires and by counting the pills taken. Comparison between basal TTR (which was calculated based on the three last INR values before prospective phase) and TTR of 4 weeks (calculated by considering the INR tests from visits 0 to 4, in the prospective phase of the study) and basal TTR and TTR of 12 weeks (calculated based on the INR tests from visits 0 to 12, in the prospective phase of the study) revealed significant statistical differences (0.144 ± 0.010 vs. 0.382 ± 0.016; and 0.144 ± 0.010 vs. 0.543 ± 0.014, p < 0.001, respectively). We also observed that the mean TTR of 1 year before (retrospective phase) was lower than TTR value after 12 weeks of pharmacist-driven treatment (prospective phase) (0.320 ± 0.015; 0.540 ± 0.015, p < 0.001). In conclusion, pharmaceutical care was able to improve TTR values in patients with AF and poor quality of anticoagulation with warfarin.

Evaluation of a pharmacogenetic-based warfarin dosing algorithm in patients with low time in therapeutic range - study protocol for a randomized controlled trial

Background

Time in therapeutic range (TTR) is a measurement of quality of warfarin therapy and lower TTR values (<50%) are associated with greater risk of thromboembolic and bleeding events. Recently, we developed a pharmacogenetic-based warfarin dosing algorithm specifically calibrated for a Brazilian patient sample. The aims of this study are: to evaluate the impact of a genetic-based algorithm, compared to traditional anticoagulation, in the time to achieve the therapeutic target and in TTR percentage; and to assess the cost-effectiveness of genotype-guided warfarin dosing in a specific cohort of patients with low TTR (<50%) from a tertiary cardiovascular hospital.

Methods/design

This study is a randomized controlled trial in patients (n = 300) with atrial fibrillation with TTR < 50%, based on the last three INR values. At the first consultation, patients will be randomized into two groups: TA group (traditional anticoagulation) and PA group (pharmacogenetic anticoagulation). For the first group, the physician will adjust the dose according to current INR value and, for the second group, a pharmacogenetic algorithm will be used. At the second, third, fourth and fifth consultations (with an interval of 7 days each) INR will be measured and, if necessary, the dose will be adjusted based on guidelines. Afterwards, patients who are INR stable will begin measuring their INR in 30 day intervals; if the patient’s INR is not stable, the patient will return in 7 days for a new measurement of the INR. Outcomes measures will include the time to achieve the therapeutic target and the percentage of TTR at 4 and 12 weeks. In addition, as a secondary end-point, pharmacoeconomic analysis will be carried out. Ethical approval was granted by the Ethics Committee for Medical Research on Human Beings of the Clinical Hospital of the University of São Paulo Medical School.

Discussion

This randomized study will include patients with low TTR and it will evaluate whether a population-specific genetic algorithm might be more effective than traditional anticoagulation for a selected group of poorly anticoagulated patients.

Trial registration

ClinicalTrials.gov, NCT02592980. Registered on 29 October 2015.

Drug Interaction Between Clopidogrel and Ranitidine or Omeprazole in Stable Coronary Artery Disease: A Double-Blind, Double Dummy, Randomized Study

BACKGROUND

Proton-pump inhibitors (PPIs) are often prescribed to patients receiving dual antiplatelet therapy (DAPT). However, this class of medication, especially omeprazole, has been associated with a reduction in clopidogrel efficacy, leading many clinicians to substitute omeprazole with ranitidine.

OBJECTIVES

Our objective was to compare the antiplatelet effect of clopidogrel before and after the addition of omeprazole or ranitidine.

METHODS

We measured platelet aggregability at baseline and after 1 week of clopidogrel 75 mg daily. Subjects were then randomized in a double-blinded, double-dummy fashion to omeprazole 20 mg twice daily (bid) or ranitidine 150 mg bid. We repeated aggregability tests after 1 additional week, using VerifyNow P2Y12™ (Accumetrics; San Diego, CA, USA), depicting aggregability as percent inhibition of platelet aggregation (IPA).

RESULTS

We enrolled 41 patients in the omeprazole group and 44 in the ranitidine group. IPA was significantly decreased after the addition of omeprazole to clopidogrel (from 26.3 ± 32.9 to 17.4 ± 33.1 %; p = 0.025), with no statistical significant changes observed in the ranitidine group (from 32.6 ± 28.9 to 30.1 ± 31.3 %; p = 0.310). The comparison of IPA in both groups at the end of the follow-up showed a trend toward significance (p = 0.07, 95 % confidence interval [CI] -1.19 to 26.59); after excluding homozygous patients for 2C19*2 genotype, the comparison of IPA between the groups reached statistical significance (32.7 ± 30.8 vs. 17.7 ± 33.4 %, respectively, for ranitidine and omeprazole groups; p = 0.04).

CONCLUSIONS

Unlike omeprazole, ranitidine did not influence platelet aggregability response to clopidogrel.

CLINICAL TRIAL REGISTRATION

NCT01896557.

Accuracy of Myocardial Biomarkers in the Diagnosis of Myocardial Infarction After Revascularization as Assessed by Cardiac Resonance: The Medicine, Angioplasty, Surgery Study V (MASS-V) Trial

BACKGROUND

The lack of a correlation between myocardial necrosis biomarkers and electrocardiographic abnormalities after revascularization procedures has resulted in a change in the myocardial infarction (MI) definition.

METHODS

Patients with stable multivessel disease who underwent percutaneous or surgical revascularization were included. Electrocardiograms and concentrations of high-sensitive cardiac troponin I (cTnI) and creatine kinase (CK)-MB were assessed before and after procedures. Cardiac magnetic resonance and late gadolinium enhancement were performed before and after procedures. MI was defined as more than five times the 99th percentile upper reference limit for cTnI and 10 times for CK-MB in percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), respectively, and new late gadolinium enhancement for cardiac magnetic resonance.

RESULTS

Of the 202 patients studied, 69 (34.1%) underwent on-pump CABG, 67 (33.2%) off-pump CABG, and 66 (32.7%) PCI. The receiver operating characteristic curve showed the accuracy of cTnI for on-pump CABG, off-pump CABG, and PCI patients was 21.7%, 28.3%, and 52.4% and for CK-MB was 72.5%, 81.2%, and 90.5%, respectively. The specificity of cTnI was 3.6%, 9.4%, and 42.1% and of CK-MB was 73.2%, 86.8%, and 96.4%, respectively. Sensitivity of cTnI was 100%, 100%, and 100% and of CK-MB was 69.2%, 64.3%, and 44.4%, respectively. The best cutoff of cTnI for on-pump CABG, off-pump CABG, and PCI was 6.5 ng/mL, 4.5 ng/mL, and 4.5 ng/mL (162.5, 112.5, and 112.5 times the 99th percentile upper reference limit) and of CK-MB was 37.5 ng/mL, 22.5 ng/mL, and 11.5 ng/mL (8.5, 5.1, and 2.6 times the 99th percentile upper reference limit), respectively.

CONCLUSIONS

Compared with cardiac magnetic resonance, CK-MB was more accurate than cTnI for diagnosing MI. These data suggest a higher troponin cutoff for the diagnosis of procedure-related MI.

Short-term follow-up of exercise training program and beta-blocker treatment on quality of life in dogs with naturally acquired chronic mitral valve disease

This study aimed to evaluate the effects of carvedilol treatment and a regimen of supervised aerobic exercise training on quality of life and other clinical, echocardiographic, and biochemical variables in a group of client-owned dogs with chronic mitral valve disease (CMVD). Ten healthy dogs (control) and 36 CMVD dogs were studied, with the latter group divided into 3 subgroups. In addition to conventional treatment (benazepril, 0.3-0.5 mg/kg once a day, and digoxin, 0.0055 mg/kg twice daily), 13 dogs received exercise training (subgroup I; 10.3 ± 2.1 years), 10 dogs received carvedilol (0.3 mg/kg twice daily) and exercise training (subgroup II; 10.8 ± 1.7 years), and 13 dogs received only carvedilol (subgroup III; 10.9 ± 2.1 years). All drugs were administered orally. Clinical, laboratory, and Doppler echocardiographic variables were evaluated at baseline and after 3 and 6 months. Exercise training was conducted from months 3-6. The mean speed rate during training increased for both subgroups I and II (ANOVA, P>0.001), indicating improvement in physical conditioning at the end of the exercise period. Quality of life and functional class was improved for all subgroups at the end of the study. The N-terminal pro-brain natriuretic peptide (NT-proBNP) level increased in subgroup I from baseline to 3 months, but remained stable after training introduction (from 3 to 6 months). For subgroups II and III, NT-proBNP levels remained stable during the entire study. No difference was observed for the other variables between the three evaluation periods. The combination of carvedilol or exercise training with conventional treatment in CMVD dogs led to improvements in quality of life and functional class. Therefore, light walking in CMVD dogs must be encouraged.

Troponin in diabetic patients with and without chronic coronary artery disease

BACKGROUND

Cardiac-specific troponin detected with the new high-sensitivity assays can be chronically elevated in response to cardiovascular comorbidities and confer important prognostic information, in the absence of unstable coronary syndromes. Both diabetes mellitus and coronary artery disease are known predictors of troponin elevation. It is not known whether diabetic patients with coronary artery disease have different levels of troponin compared with diabetic patients with normal coronary arteries. To investigate this question, we determined the concentrations of a level 1 troponin assay in two groups of diabetic patients: those with multivessel coronary artery disease and those with angiographically normal coronary arteries.

METHODS

We studied 95 diabetic patients and compared troponin in serum samples from 50 patients with coronary artery disease (mean age = 63.7, 58 % male) with 45 controls with angiographically normal coronary arteries. Brain natriuretic peptide and the oxidative stress biomarkers myeloperoxidase, nitrotyrosine and oxidized LDL were also determined.

RESULTS

Diabetic patients with coronary artery disease had higher levels of troponin than did controls (median values, 12.0 pg/mL (95 % CI:10-16) vs 7.0 pg/mL (95 % CI: 5.9-8.5), respectively; p = 0.0001). The area under the ROC curve for the diagnosis of CAD was 0.712 with a sensitivity of 70 % and a specificity of 66 %. Plasma BNP levels and oxidative stress variables (myeloperoxidase, nitrotyrosine, and oxidized LDL) were not different between the two groups. In a multivariate analysis, gender (p = 0.04), serum glucose (0.03) and Troponin I (p = 0.01) had independent statistical significance.

CONCLUSION

Troponin elevation is related to the presence of chronic coronary artery disease in diabetic patients with multiple associated cardiovascular risk factors. Troponin may serve as a biomarker in this high-risk population.

TRIAL REGISTRATION

http://www.controlled-trials.com

REGISTRATION NUMBER

ISRCTN26970041.

Development of a pharmacogenetic-based warfarin dosing algorithm and its performance in Brazilian patients: highlighting the importance of population-specific calibration

BACKGROUND

The main aims of the present study were to develop a pharmacogenetic-based warfarin dosing algorithm and to validate it in a highly admixed population.

MATERIALS & METHODS

We included two patient cohorts treated with warfarin (first cohort, n = 832; and second cohort, n = 133).

RESULTS

Our algorithm achieved a determination coefficient of 40% including the variables age, gender, weight, height, self-declared race, amiodarone use, enzyme inducers use, VKORC1 genotypes and predicted phenotypes according to CYP2C9 polymorphisms.

CONCLUSION

Data suggest that our developed algorithm is more accurate than the IWPC algorithm when the application is focused on patients from the Brazilian population. Population-specific derivation and/or calibration of warfarin dosing algorithms may lead to improved performance compared with general use dosing algorithms currently available. Original submitted 26 November 2014; Revision submitted 9 April 2015.

Simultaneous use of amiodarone influences warfarin maintenance dose but is not associated with adverse events

BACKGROUND

Drug interaction studies selecting patients in a real-life setting are scarce, and most studies to date are characterized by a small sample size.

OBJECTIVE

To evaluate the effect of amiodarone on warfarin maintenance dose and adverse events in an anticoagulation cohort from a tertiary cardiovascular service.

METHODS

This study recruited 866 patients, and oral anticoagulant therapy was monitored by the prothrombin time expressed as the international normalized ratio (INR). Genotyping of CYP2C9*2, CYP2C9*3, and VKORC1 3673 polymorphisms was performed.

RESULTS

Of the 866 patients, 111 (12.8%) were taking amiodarone and warfarin simultaneously, and 514 (59.4%) reached the therapeutic target dose. The warfarin maintenance dose was significantly lower in patients simultaneously using amiodarone (23.8 ± 11.3 mg/wk) compared with other patients (29.5 ± 14.3 mg/wk; P < 0.001). Patients taking amiodarone had higher INR/current dose ratios (0.83 ± 0.04 per mg) compared with patients not using amiodarone (0.71 ± 0.02 per mg, P = 0.001). Adverse event frequency was not different between the groups (P = 0.40). No genotype effect was noted on the odds of bleeding associated with amiodarone use.

CONCLUSIONS

Simultaneous use of amiodarone influences warfarin maintenance dose, but is not associated with adverse events.

Gender differences in serum CK-MB mass levels in healthy Brazilian subjects

The creatine kinase-isoenzyme MB (CK-MB) mass assay is one of the laboratory tests used for the diagnosis of myocardial infarction. It is recommended, however, that reference limits should take gender and race into account. In the present study, we analyzed the plasma CK-MB mass and troponin levels of 244 healthy volunteers without a personal history of coronary artery disease and with no chronic diseases, muscular trauma or hypothyroidism, and not taking statins. The tests were performed with commercial kits, CK-MB mass turbo kit and Troponin I turbo kit, using the Immulite 1000 analyzer from Siemens Healthcare Diagnostic. The values were separated according to gender and showed significant differences by the Mann-Whitney test. Mean (± SD) CK-MB mass values were 2.55 ± 1.09 for women (N = 121; age = 41.20 ± 10.13 years) and 3.49 ± 1.41 ng/mL for men (N = 123; age = 38.16 ± 11.12 years). Gender-specific reference values at the 99th percentile level, according to the Medicalc statistical software, were 5.40 ng/mL for women and 7.13 ng/mL for men. The influence of race was not considered because of the high miscegenation of the Brazilian population. The CK-MB values obtained were higher than the 5.10 mg/mL proposed by the manufacturer of the laboratory kit. Therefore, decision limits should be related to population and gender in order to improve the specificity of this diagnostic tool, avoiding misclassification of patients.

Study of pro-thrombotic and pro-inflammatory factors in Chagas cardiomyopathy

BACKGROUND

The relationship between inflammatory and prothrombotic activity in chagas cardiomyopathy and in other etiologies is unclear.

OBJECTIVE

To study the profile of pro-thrombotic and pro-inflammatory markers in patients with Chagas' heart failure and compare them with patients of non-chagas etiology.

METHODS

Cross-sectional cohort.

INCLUSION CRITERIA

left ventricle ejection fraction (LVEF) < 45% and onset time to symptoms > one month. The patients were divided into two groups: group 1 (G1) - seropositive for Chagas - and group 2 (G2) - seronegative for Chagas. Pro-inflammatory factor: Ultra-sensitive CRP. Pro-thrombotic factors: thrombin-antithrombin factor, fibrinogen, von Willebrand factor antigen, plasma P-selectin and thromboelastography. Sample calculated for 80% power, assuming a standard deviation difference of 1/3; significant p if it is < 0.05.

STATISTICAL ANALYSIS

Fisher's exact test for categorical variables; unpaired Student's t-test for parametric continuous variables and Mann-Whitney test for nonparametric continuous variables.

RESULTS

Between January and June 2008, 150 patients were included, 80 in G1 and 70 in G2. Both groups maintained the averages of high sensitivity CRP above baseline values, however, there was no significant difference (p = 0.328). The fibrinogen levels were higher in G2 than in G1 (p = 0.015). Among the thromboelastography variables, the parameters MA (p=0.0013), G (p=0.0012) and TG (p =0.0005) were greater in G2 than in G1.

CONCLUSION

There is no evidence of greater pro-thrombotic status among patients with Chagas disease. The levels of fibrinogen and the MA, G and TG parameters of the thromboelastography point to pro-thrombotic status among non-chagas patients. Both groups had increased inflammatory activity.