Stanislav Simek

Clopidogrel pre-treatment in stable angina: for all patients >6 h before elective coronary angiography or only for angiographically selected patients a few minutes before PCI? A randomized multicentre trial PRAGUE-8

Aims To compare two different clopidogrel regimens on the outcomes of patients undergoing elective coronary angiography (CAG)±ad hoc percutaneous coronary intervention (PCI). Methods and results Open-trial randomized 1028 patients with stable angina to group A (‘non-selective’—clopidogrel 600 mg >6 h before CAG; n = 513) or group B (‘selective’—clopidogrel 600 mg in the cath-lab after CAG, only in case of PCI; n = 515). Combined primary endpoint was death/periprocedural myocardial infarction (MI)/stroke/re-intervention within 7 days. Secondary endpoints were troponin elevation and bleeding complications. Primary endpoint occurred in 0.8% group A patients vs. 1% group B (P = 0.749; 90% CI for the percentage difference −1.2–0.8). Periprocedural troponin elevation (>3× ULN) was detected in 2.6% group A vs. 3.3% group B (P = 0.475; 90% CI −2.5–1.0). Bleeding complications occurred in 3.5% group A patients vs. 1.4% group B (P = 0.025). After adjustment for covariates and factors that may influence the bleeding risk, patients in group A were shown to have more likely bleeding complications when compared with group B (OR = 3.03; 95% CI 1.14–8.10; P = 0.027). Conclusion High (600 mg) loading dose of clopidogrel before elective CAG increased the risk of minor bleeding complications, while the benefit on periprocedural infarction was not significant. Clopidogrel can be given safely in the catheterization laboratory between CAG and PCI in chronic stable angina patients.

Prasugrel versus Ticagrelor in Patients with Acute Myocardial Infarction Treated with Primary Percutaneous Coronary Intervention: Multicenter Randomized PRAGUE-18 Study

Background: No randomized head-to-head comparison of the efficacy and safety of ticagrelor and prasugrel has been published in the 7 years since the higher efficacy of these newer P2Y12 inhibitors were first demonstrated relative to clopidogrel. Methods: This academic study was designed to compare the efficacy and safety of prasugrel and ticagrelor in acute myocardial infarction treated with primary or immediate percutaneous coronary intervention. A total of 1230 patients were randomly assigned across 14 sites to either prasugrel or ticagrelor, which was initiated before percutaneous coronary intervention. Nearly 4% were in cardiogenic shock, and 5.2% were on mechanical ventilation. The primary end point was defined as death, reinfarction, urgent target vessel revascularization, stroke, or serious bleeding requiring transfusion or prolonging hospitalization at 7 days (to reflect primarily the in-hospital phase). This analysis presents data from the first 30 days (key secondary end point). The total follow-up will be 1 year for all patients and will be completed in 2017. Results: The study was prematurely terminated for futility. The occurrence of the primary end point did not differ between groups receiving prasugrel and ticagrelor (4.0% and 4.1%, respectively; odds ratio, 0.98; 95% confidence interval, 0.55–1.73; P=0.939). No significant difference was found in any of the components of the primary end point. The occurrence of key secondary end point within 30 days, composed of cardiovascular death, nonfatal myocardial infarction, or stroke, did not show any significant difference between prasugrel and ticagrelor (2.7% and 2.5%, respectively; odds ratio, 1.06; 95% confidence interval, 0.53–2.15; P=0.864). Conclusions: This head-to-head comparison of prasugrel and ticagrelor does not support the hypothesis that one is more effective or safer than the other in preventing ischemic and bleeding events in the acute phase of myocardial infarction treated with a primary percutaneous coronary intervention strategy. The observed rates of major outcomes were similar but with broad confidence intervals around the estimates. These interesting observations need to be confirmed in a larger trial. Clinical Trial Registration: URL: http://www.ClinicalTrials.gov. Unique identifier: NCT02808767.

Factors influencing clopidogrel efficacy in patients with stable coronary artery disease undergoing elective percutaneous coronary intervention: statin's advantage and the smoking "paradox".

Purpose: The aim was to identify factors that influence the efficacy of 600 mg of clopidogrel pretreatment in patients with stable coronary artery disease undergoing elective percutaneous coronary intervention. Methods: In a laboratory substudy of the PRAGUE-8 trial, the influences of nonmodifiable (age and sex) and modifiable (body mass index and tobacco smoke) factors, comorbidity (hypertension, hyperlipidemia, diabetes mellitus, and renal insufficiency) and cotherapy (statin, aspirin, and heparin), on the course of clopidogrel efficacy were investigated in 105 patients pretreated with clopidogrel ≥6 hours before coronary angiography ± percutaneous coronary intervention. Flow cytometric analysis of the vasodilator-stimulated phosphoprotein phosphorylation state was used. Independent predictors that influenced clopidogrel action were identified using linear regression. Results: There was no correlation between baseline platelet reactivity index (PRI) and severity of coronary atherosclerosis; mean index of platelet reactivity for a nonsignificant lesion was 72% ± 5.98% and for a significant lesion 70.08% ± 8.43%. The highest proportion of low responders was patients with diabetes (50% at 28 hours). Among tobacco smokers, the response to clopidogrel occurred quickly and 80% of smokers had effective inhibition of PRI, 12 hours after drug use. After adjustments, tobacco smoking was an independent predictor for the most robust drop of PRI 12 hours after clopidogrel (P = 0.027). The magnitude of total decrease of PRI at 28 hours was not significantly influenced by cigarette smoking (P = 0.12). Linear regression showed that patients on statin therapy had a better response to clopidogrel than those without statins-the mean decrease of PRI at 28 hours was significantly higher (P = 0.02) among these patients (40.0 vs. 27.6). Conclusions: In stable coronary artery disease, no correlation exists between baseline PRI and the severity and extent of coronary atherosclerosis. A high loading dose of clopidogrel does not satisfactorily suppress enhanced PRI in patients with diabetes. Cigarette smoking is independently associated with a prompt antiplatelet response to clopidogrel. Ongoing statin therapy is an independent determinant of more effective clopidogrel-mediated inhibition of platelet reactivity.

Time course of endothelin-1 plasma level in patients with acute coronary syndromes.

An elevated plasma level of endothelin-1 was reported in several cardiovascular conditions including unstable angina pectoris and myocardial infarction. The present study was designed to evaluate the time course of the endothelin-1 release in unstable angina pectoris and to assess its relationship to the development of myocardial infarction and coronary vessel occlusion. The cohort studied included 32 patients with the clinical diagnosis of unstable angina pectoris who had been admitted to the coronary care unit and subsequently underwent coronary angiography (group A). Fourteen patients with chronic stable angina pectoris referred to routine diagnostic coronary angiography served as the control group (group B). A significant difference in the endothelin-1 plasma level was found between both groups, the values being 10.2 ± 5.3 and 6.0 ± 3.1 pg/ml (p < 0.01), respectively. There were, however, no significant differences between the following subdivisions of group A: patients with and without subsequent myocardial infarction; those with angiographically documented occlusion of at least one major branch of the coronary artery and no occlusion; and finally, those with persisting symptoms of angina pectoris and with favorable response to treatment. Neither was there any difference found among the subgroups differing in the time interval between the onset of chest pain and blood sampling. The time course of endothelin plasma concentrations showed elevated values lasting for more than 96 h after the index episode of prolonged chest pain. No correlation with the subsequent clinical course could be inferred. Thus, plasma endothelin level was elevated in patients with unstable angina pectoris and myocardial infarction and the increase persisted for several days after the onset of symptoms.

Platelet gene polymorphisms and risk of bleeding in patients undergoing elective coronary angiography: A genetic substudy of the PRAGUE-8 trial

AIM Utilization of cardiac catheterization has increased dramatically over time. Bleeding is a major prognostic predictor after percutaneous coronary catheterization procedures. This study aimed to assess the impact of eight polymorphisms of genes encoding platelet receptors and enzymes on the risk of bleeding in patients undergoing elective coronary angiography (CAG). METHODS Polymorphisms of platelet receptors, GP Ia (807C>T, rs1126643), GP VI (13254T>C, rs1613662), GP IIIa (HPA-1, rs5918), PAR-1 (IVS-14A>T, rs168753), P2Y(12) (34C>T, rs6785930 and H1/H2 haplotype, rs2046934), and genetic variations of the gene coding for cyclooxygenase-1 (COX-1) (-842A>G, rs10306114 and 50C>T, rs3842787) were studied. The frequencies of gene polymorphisms carriers were investigated in 696 patients undergoing elective CAG because of suspected or proven stable coronary artery disease. Genotyping was done using PCR, followed by melting curve analysis with specific fluorescent hybridization probes. RESULTS In patients undergoing elective CAG (without ad hoc percutaneous coronary intervention (PCI) and without clopidogrel pretreatment) a significant association was found between bleeding risk and variations in the gene coding for COX-1 (-842A>G and 50C>T) (both p=0.013). Six other investigated polymorphisms did not show any influence on bleeding complications. After controlling for potential bleeding confounders, the association between COX-1 gene polymorphisms (-842A>G and 50C>T) and bleeding risk remained statistically significant (both odds ratios 12.1, p=0.012). CONCLUSION Cyclooxygenase-1 -842G and 50T alleles significantly contribute to the risk of bleeding complications in patients undergoing elective CAG. Genetic testing is able to influence the safety of diagnostic cardiac catheterization in large numbers of low risk patients with borderline indications.

Optimal pretreatment timing for high load dosing (600 mg) of clopidogrel before planned percutaneous coronary intervention for maximal antiplatelet effectiveness

BACKGROUND The optimal timing for 600 mg clopidogrel pre-treatment before planned PCI in patients with stable coronary artery disease has never been tested in a randomized trial. METHODS The time course of platelet inhibition was investigated in 105 patients pre-treated with clopidogrel ≥ 6 h before the planned procedure. Flow cytometric analysis of the vasodilator stimulated phosphoprotein (VASP) phosphorylation state was done and a Platelet Reactivity Index (PRI) was calculated prior to treatment (baseline) and at 12, 28, 36, 60, 84 and 108 h after the clopidogrel loading dose administration. RESULTS The maximal inhibition of platelet activation was seen at 28 h post administration (PRI mean 36 ± 23%), and 2/3 of patients had PRI value <50%. At 12 h 47% of patients had PRI value ≥ 50% (mean 45±21%). 600 mg of clopidogrel significantly suppressed platelet activation for 4 days. A correlation was between baseline PRI and its values by 28 h (r(S)=0.48, p<0.001), between 12 h-28 h the correlation was strong (r(S)=0.77, p<0.001). CONCLUSION The time curve of clopidogrel efficacy was dependent on baseline platelet reactivity. Among stable CAD patients, pre-treatment with 600 mg of clopidogrel resulted in maximal antiplatelet efficacy 1 day after drug administration.

Local Changes in the Plasma Endothelin Level in the Coronary Artery Immediately after Percutaneous Transluminal Coronary Angioplasty

Endothelin plays an important role in cardiovascular pathology. As one of the most important endothelium-derived vasoconstrictor substances, endothelin together with endothelium-derived vasodilating factor control vascular tone and contribute to the vasoconstrictory response if the production of endothelium-derived vasodilating factor is impaired. The aim of the study was to assess the changes of the local endothelin level in coronary circulation immediately after percutaneous transluminal coronary angioplasty (PTCA). Plasma endothelin levels were measured in blood samples from the peripheral vein and ostium of the coronary artery before the angioplasty, and from the distal coronary artery just beyond the dilated segment and the peripheral vein immediately after the procedure. The plasma endothelin level was significantly higher in the ostium of the coronary artery already prior to PTCA as compared to the peripheral vein (10.9 +/- 3.4 vs. 7.2 +/- 2.1 pg/ml, p < 0.005). There was no change in the endothelin level in the coronary artery distal to the dilated segment immediately after the procedure as compared to the initial level, although this level was higher than the postangioplasty venous level (9.8 +/- 2.9 vs. 7.7 +/- 2.0 pg/ml, p < 0.005). Individual changes in coronary-artery plasma endothelin levels as a response to coronary angioplasty were disparate. An increase and a decrease in coronary artery plasma endothelin levels by more than 2 pg/ml after coronary angioplasty were observed in 3 and 6 subjects, respectively. In conclusion, increased plasma endothelin levels were found in blood samples drawn from the coronary artery as compared to the peripheral vein. There was no further change in the plasma endothelin level in the coronary artery distal to the dilated segment after angioplasty; however, the individual responses were disparate.

Endothelin Concentrations in Coronary Sinus during Atrial Pacing-Induced Myocardial Ischemia

To investigate the possible role of endothelin in coronary vasoconstriction contributing to the development of myocardial ischemia, plasma endothelin concentrations at rest and during atrial pacing-induced myocardial ischemia have been measured in blood samples drawn from the aorta and coronary sinus in 12 patients with significant narrowing of the left anterior descending coronary artery. The plasma endothelin concentrations at rest were similar in the aorta (AO/R) and coronary sinus (CS/R) (4.8 +/- 2.4 and 4.5 +/- 1.7 pg/ml, respectively), the difference between coronary sinus and aorta plasma endothelin concentration (CS/R-AO/R) being -0.3 +/- 1.7 pg/ml. During atrial pacing-induced myocardial ischemia aortic plasma endothelin concentration (AO/P) did not change (4.6 +/- 2.6 pg/ml) and only an insignificant increase in the plasma endothelin concentration in the coronary sinus (CS/P) was observed (5.3 +/- 2.8 pg/ml). The difference between coronary sinus and aortic endothelin plasma concentration (CS/P-AO/P) was 0.6 +/- 2.5 pg/ml. Finally, the difference in endothelin concentrations between coronary sinus and aorta rose only insignificantly during pacing as compared to the resting values ([CS/P-AO/P]-[CS/R-AP/R] being 0.9 +/- 3.2 pg/ml). Thus, atrial pacing-induced myocardial ischemia in patients with significant left anterior descending coronary artery stenosis was not accompanied by significant changes in coronary sinus plasma endothelin concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Herpes simplex virus-induced cardiomyopathy successfully treated with acyclovir

ZusammenfassungDie entzündliche dilatative Kardiomyopathie stellt eine erworbene Form der dilatativen Kardiomyopathie dar, wobei Virusinfektionen die häufigste Ursache darstellen. Im Gegensatz zu anderen kardiotropen Viren, wird das Herpes simplex Virus (HSV) nur selten in Biopsien des Myokards von Patienten mit dilatativer Kardiomyopathie gefunden. Wir berichten über einen Fall einer erfolgreichen Behandlung mit Azyclovir einer durch HSV induzierten Kardiomyopathie.SummaryInflammatory dilated cardiomyopathy (DCMi) represents an acquired form of dilated cardiomyopathy. Viral infection is the most common cause of DCMi. In contrast with other cardiotropic viruses, herpes simplex virus (HSV) is a very rare finding in endomyocardial biopsies of patients with dilated cardiomyopathy. We report a case of HSV-induced cardiomyopathy successfully treated with acyclovir.