Antonio Fernández-Ortiz

Characterization of the relative thrombogenicity of atherosclerotic plaque components: Implications for consequences of plaque rupture☆

OBJECTIVES The purpose of this study was to determine whether different components of human atherosclerotic plaques exposed to flowing blood resulted in different degrees of thrombus formation. BACKGROUND It is likely that the nature of the substrate exposed after spontaneous or angioplasty-induced plaque rupture is one factor determining whether an unstable plaque proceeds rapidly to an occlusive thrombus or persists as a nonocclusive mural thrombus. Although observational data show that plaque rupture is a potent stimulus for thrombosis, and exposed collagen is suggested to have a predominant role in thrombosis, the relative thrombogenicity of different components of human atherosclerotic plaques is not well established. METHODS We investigated thrombus formation on foam cell-rich matrix (obtained from fatty streaks), collagen-rich matrix (from sclerotic plaques), collagen-poor matrix without cholesterol crystals (from fibrolipid plaques), atheromatous core with abundant cholesterol crystals (from atheromatous plaques) and segments of normal intima derived from human aortas at necropsy. Specimens were mounted in a tubular chamber placed within an ex vivo extracorporeal perfusion system and exposed to heparinized porcine blood (mean [+/- SEM] activated partial thromboplastin time ratio 1.5 +/- 0.04) for 5 min under high shear rate conditions (1,690 s-1). Thrombus was quantitated by measurement of indium-labeled platelets and morphometric analysis. Under similar conditions, substrates were perfused with heparinized human blood (2 IU/ml) in an in vitro system, and thrombus formation was similarly evaluated. RESULTS Thrombus formation on atheromatous core was up to sixfold greater than that on other substrates, including collagen-rich matrix (p = 0.0001) in both heterologous and homologous systems. Although the atheromatous core had a more irregular exposed surface and thrombus formation tended to increase with increasing roughness, the atheromatous core remained the most thrombogenic substrate when the substrates were normalized by the degree of irregularity as defined by the roughness index (p = 0.002). CONCLUSIONS The atheromatous core is the most thrombogenic component of human atherosclerotic plaques. Therefore, plaques with a large atheromatous core content are at high risk of leading to acute coronary syndromes after spontaneous or mechanically induced rupture because of the increased thrombogenicity of their content.

Contribution of Gene Sequence Variations of the Hepatic Cytochrome P450 3A4 Enzyme to Variability in Individual Responsiveness to Clopidogrel

Objectives—Metabolic activity of cytochrome P450 (CYP) 3A4 has been associated with clopidogrel response variability. Because metabolic activity of CYP3A4 is genetically regulated, we hypothesized that genetic variations of this enzyme may contribute to clopidogrel response variability. Methods and Results—The CYP3A4*1B, CYP3A4*3, IVS7+258A>G, IVS7+894C>T, and IVS10+12G>A polymorphisms of the CYP3A4 gene were assessed in 82 patients in a steady phase of clopidogrel therapy. Glycoprotein (platelet glycoprotein (GP) IIb/IIIa receptor activation and platelet aggregation were assessed. A cohort of 45 clopidogrel-naïve patients was studied to determine the modulating effects of these polymorphisms after loading dose (300 mg) administration. Only the IVS7+258A>G, IVS7+894C>T, and IVS10+12G>A polymorphisms were sufficiently polymorphic. During the steady phase of clopidogrel treatment, IVS10+12A allele carriers had reduced GP IIb/IIIa activation (P=0.025) and better responsiveness (P=0.02); similarly, clopidogrel-naïve patients carriers of the IVS10+12A allele had reduced GP IIb/IIIa activation during the first 24 hours after a loading dose (P=0.025), increased platelet inhibition (P=0.006), and a more optimal drug response (P=0.003). This polymorphism did not influence platelet aggregation profiles. No association was observed between the other polymorphisms and clopidogrel responsiveness. Conclusions—The IVS10+12G>A polymorphism of the CYP3A4 gene modulates platelet activation in patients treated with clopidogrel and may therefore contribute to clopidogrel response variability.

Long-Term Clinical and Echocardiographic Follow-Up After Percutaneous Mitral Valvuloplasty With the Inoue Balloon

BACKGROUND The objective of this study was to assess the long-term clinical outcome and valvular changes (area and regurgitation) after percutaneous mitral valvuloplasty (PMV). METHODS AND RESULTS After PMV, 561 patients were followed up for 39 (+/-23) months and clinical/echocardiographic data obtained yearly. Kaplan-Meier and Cox regression analyses were performed to estimate event-free survival, its predictors, and the relative risks of several patient subgroups. There were several nonexclusive events: 19 (3.3%) cardiac deaths, 55 (9.8%) mitral replacements, 6 (1%) repeated PMVs, 56 (10%) cases of restenosis, and 108 (19%) cases of clinical impairment. Survival free of major events (cardiac death, mitral surgery, repeat PMV, or functional impairment) was 69% at 7 years, ranging from 88% to 40% in different subgroups of patients. Wilkins score was the best preprocedural predictor of mitral opening, but the procedural result (mitral area and regurgitation) was the only independent predictor of major event-free survival. Mitral area loss, though mild [0.13 (+/-0.21)cm2], increased with time and was >/=0.3 cm2 in 12%, 22%, and 27% of patients at 3, 5, and 7 years, respectively. Regurgitation did not progress in 81% of patients, and when it occurred it was usually by 1 grade. CONCLUSIONS Seven years after PMV, more than two thirds of patients were in good clinical condition and free of any major event. The procedural result was the main determinant of long-term outcome, although a high score had also negative implications. Mitral area decreased progressively over time, whereas regurgitation did not tend to progress.

Impact of Chronic Kidney Disease on Platelet Function Profiles in Diabetes Mellitus Patients With Coronary Artery Disease Taking Dual Antiplatelet Therapy

OBJECTIVES We sought to assess the impact of renal function on platelet reactivity in patients with diabetes mellitus (DM) and coronary artery disease on aspirin and clopidogrel therapy. BACKGROUND Diabetes mellitus is a key risk factor for chronic kidney disease (CKD). In aspirin-treated DM patients the presence of moderate/severe CKD is associated with reduced clinical efficacy of adjunctive clopidogrel therapy. Whether these findings may be attributed to differences in clopidogrel-induced effects is unknown. METHODS This was a cross-sectional observational study in which DM patients taking maintenance aspirin and clopidogrel therapy were studied. Patients were categorized into 2 groups according to the presence or absence of moderate/severe CKD. Platelet aggregation after adenosine diphosphate (ADP) and collagen stimuli were assessed with light transmittance aggregometry and defined patients with high post-treatment platelet reactivity (HPPR). Markers of platelet activation, including glycoprotein IIb/IIIa activation and P-selectin expression, were also determined using flow cytometry. RESULTS A total of 306 DM patients were analyzed. Patients with moderate/severe CKD (n = 84) had significantly higher ADP-induced (60 +/- 13% vs. 52 +/- 15%, p = 0.001) and collagen-induced (49 +/- 20% vs. 41 +/- 20%, p = 0.004) platelet aggregation compared with those without (n = 222). After adjustment for potential confounders, patients with moderate/severe CKD were more likely to have HPPR after ADP (adjusted odds ratio: 3.8, 95% confidence interval: 1.7 to 8.5, p = 0.001) and collagen (adjusted odds ratio: 2.4; 95% confidence interval: 1.1 to 5.4; p = 0.029) stimuli. Markers of platelet activation were significantly increased in patients with HPPR. CONCLUSIONS In DM patients with coronary artery disease taking maintenance aspirin and clopidogrel therapy, impaired renal function is associated with reduced clopidogrel-induced antiplatelet effects and a greater prevalence of HPPR.

Effect of Early Metoprolol on Infarct Size in ST-Segment–Elevation Myocardial Infarction Patients Undergoing Primary Percutaneous Coronary Intervention The Effect of Metoprolol in Cardioprotection During an Acute Myocardial Infarction (METOCARD-CNIC) Trial

Background —The effect of β-blockers on infarct size when used in conjunction with primary percutaneous coronary intervention (PCI) is unknown. We hypothesize that metoprolol reduces infarct size when administered early (intravenously [i.v.] before reperfusion). Methods and Results —Patients with Killip-class ≤II anterior ST-segment elevation myocardial infarction (STEMI) undergoing PCI within 6 hours of symptoms onset were randomized to receive i.v. metoprolol (n=131) or not (control, n=139) pre-reperfusion. All patients without contraindications received oral metoprolol within 24 hours. The pre-defined primary endpoint was infarct size on magnetic resonance imaging (MRI) performed 5-7 days after STEMI. MRI was performed in 220 patients (81%). Mean (±SD) infarct size by MRI was smaller after i.v. metoprolol compared to control (25.6±15.3 vs. 32.0±22.2 grams; adjusted difference, -6.52; 95% confidence interval [CI], -11.39 to -1.78; P=0.012). In patients with pre-PCI TIMI flow grade 0/1, the adjusted treatment difference in infarct size was -8.02; 95% CI, -13.01 to -3.02; P=0.0029. Infarct size estimated by peak and area under the curve creatine-kinase release was measured in all study population and was significantly reduced by i.v. metoprolol. Left ventricular ejection fraction was higher in the i.v. metoprolol group (adjusted difference 2.67%; 95% CI, 0.09% to 5.21%; P=0.045). The composite of death, malignant ventricular arrhythmia, cardiogenic shock, atrioventricular block and reinfarction at 24 hours in the i.v. metoprolol and control groups respectively was 7.1% vs. 12.3%, p=0.21. Conclusions —In patients with anterior Killip-class ≤II STEMI undergoing primary PCI, early i.v. metoprolol before reperfusion reduced infarct size and increased LVEF with no excess of adverse events during the first 24 hours after STEMI. Clinical Trial Registration Information —ClinicalTrials.gov. Identifier: [NCT01311700][1] & EUDRACT Number 2010-019939-35. [1]: /lookup/external-ref?link_type=CLINTRIALGOV&access_num=NCT01311700&atom=%2Fcirculationaha%2Fearly%2F2013%2F09%2F03%2FCIRCULATIONAHA.113.003653.atomBackground— The effect of &bgr;-blockers on infarct size when used in conjunction with primary percutaneous coronary intervention is unknown. We hypothesize that metoprolol reduces infarct size when administered early (intravenously before reperfusion). Methods and Results— Patients with Killip class II or less anterior ST-segment–elevation myocardial infarction (STEMI) undergoing percutaneous coronary intervention within 6 hours of symptoms onset were randomized to receive intravenous metoprolol (n=131) or not (control, n=139) before reperfusion. All patients without contraindications received oral metoprolol within 24 hours. The predefined primary end point was infarct size on magnetic resonance imaging performed 5 to 7 days after STEMI. Magnetic resonance imaging was performed in 220 patients (81%). Mean±SD infarct size by magnetic resonance imaging was smaller after intravenous metoprolol compared with control (25.6±15.3 versus 32.0±22.2 g; adjusted difference, −6.52; 95% confidence interval, −11.39 to −1.78; P=0.012). In patients with pre–percutaneous coronary intervention Thrombolysis in Myocardial Infarction grade 0 to 1 flow, the adjusted treatment difference in infarct size was −8.13 (95% confidence interval, −13.10 to −3.16; P=0.0024). Infarct size estimated by peak and area under the curve creatine kinase release was measured in all study populations and was significantly reduced by intravenous metoprolol. Left ventricular ejection fraction was higher in the intravenous metoprolol group (adjusted difference, 2.67%; 95% confidence interval, 0.09–5.21; P=0.045). The composite of death, malignant ventricular arrhythmia, cardiogenic shock, atrioventricular block, and reinfarction at 24 hours in the intravenous metoprolol and control groups was 7.1% and 12.3%, respectively (P=0.21). Conclusions— In patients with anterior Killip class II or less ST-segment–elevation myocardial infarction undergoing primary percutaneous coronary intervention, early intravenous metoprolol before reperfusion reduced infarct size and increased left ventricular ejection fraction with no excess of adverse events during the first 24 hours after STEMI. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01311700. EUDRACT number: 2010-019939-35.

Effect of an eccentric severe stenosis on fibrin(ogen) deposition on severely damaged vessel wall in arterial thrombosis. Relative contribution of fibrin(ogen) and platelets.

BackgroundCoronary thrombosis is a dynamic process dependent on the pathological substrate, the local shear forces, and blood factors. Methods and ResultsWe investigated the effect of a severe (80%) eccentric stenosis on fibrin(ogen) interaction with a deeply damaged vessel wall, its relation to platelet deposition in thrombus formation, and the influence of time on thrombus growth. Porcine 125I-fibrinogen and autologous 111In-platelets were injected into pigs instrumented for extracorporeal circulation and treated with low-dose heparin (aPTT ratio < 1.5) that has been previously shown and herein confirmed not to affect platelet and/or fibrin(ogen) attachment. Tunica media, as a model of severely injured vessel wall, was mounted in a tubular perfusion chamber containing an eccentric axisymmetric sinusoidal stenosis obstructing the lumen and exposed for 1, 5, and 10 minutes to perfusing blood. A shear rate of 424 s−1 at the laminar, parallel parabolic local flow perfused segments one to two orders of magnitude greater at the apex of the stenosis. Fibrin(ogen) deposition, its axial distribution with respect to the apex, and its relation to platelet deposition were determined by an ex vivo analysis of the test substrates. Fibrin(ogen) and platelet deposition were both significantly higher at the apex of the stenosis than at either the prestenotic or poststenotic area at all the studied perfusion times (P<.02). However, fibrin(ogen) deposition demonstrated a significantly smaller degree of increase from the prestenotic area to the apex as well as a smaller degree of decrease from the latter to the poststenotic region, compared with platelet deposition (P<.05). Although both fibrin(ogen) and platelet deposition increased over time, the ratio of fibrin(ogen) to platelets showed a progressive decrease that became significant from 5 to 10 minutes (P<.03) at either low or high shear rate. The rate of platelet deposition was relatively constant; however, fibrin(ogen) deposition progressively decreased, especially at the apex. ConclusionsOn severely damaged vessel wall, fibrin(ogen) and platelet deposition is maximal at the apex of the stenosis where shear rate is extremely high and parallel streamlines are deformed. Nevertheless, fibrin(ogen) deposition is significantly less dependent on high shear rate than is platelet deposition, and the pattern is not influenced by time. Finally, fibrin(ogen) deposition appears to be predominant in the thrombus layers adjacent to a severely damaged vessel wall regardless of the local shear stress levels and flow conditions.

Circadian variations of infarct size in acute myocardial infarction

Background The circadian clock influences a number of cardiovascular (patho)physiological processes including the incidence of acute myocardial infarction. A circadian variation in infarct size has recently been shown in rodents, but there is no clinical evidence of this finding. Objective To determine the impact of time-of-day onset of ST segment elevation myocardial infarction (STEMI) on infarct size. Methods A retrospective single-centre analysis of 811 patients with STEMI admitted between 2003 and 2009 was performed. Infarct size was estimated by peak enzyme release. The relationship between peak enzyme concentrations and time-of-day were characterised using multivariate regression splines. Time of STEMI onset was divided into four 6-hour periods in phase with circadian rhythms. Results Model comparisons based on likelihood ratio tests showed a circadian variation in infarct size across time-of-day as evaluated by peak creatine kinase (CK) and troponin-I (TnI) concentrations (p=0.015 and p=0.012, respectively). CK and TnI curves described similar patterns across time, with a global maximum in the 6:00–noon period and a local minimum in the noon–18:00 period. Infarct size was largest in patients with STEMI onset in the dark-to-light transition period (6:00–noon), with an increase in peak CK and TnI concentrations of 18.3% (p=0.031) and 24.6% (p=0.033), respectively, compared with onset of STEMI in the 18:00–midnight period. Patients with anterior wall STEMI also had significantly larger infarcts than those with STEMI in other locations. Conclusions Significant circadian oscillations in infarct size were found in patients according to time-of-day of STEMI onset. The infarct size was found to be significantly larger with STEMI onset in the dark-to-light transition period (6:00–noon). If confirmed, these results may have a significant impact on the interpretation of clinical trials of cardioprotective strategies in STEMI.

Role of thrombosis in atherosclerosis and its complications.

The endothelium is intact but activated and dysfunctioning during the early phase of atherogenesis. Owing to increased endothelial permeability, many blood-derived components, including hemostatic factors, are present in early as well as advanced atherosclerotic lesions. Insudated fibrin(ogen) and related degradation products and thrombin could contribute to atherogenesis by their chemotactic (attracting monocytes/macrophages) and mitogenic (stimulating cell proliferation) properties. All key cells in plaque may express thrombin receptors, indicating that thrombin may play a role in the genesis of uncomplicated atherosclerosis by mediating inflammatory and proliferative processes. Later, endothelial denudation with platelet adherence occurs over mature plaques. Then, incorporation of microthrombi and probably platelet/thrombus-derived growth factors are critical for the progressive growth of the smooth muscle cell-related plaque component. Besides transendothelial influx and incorporation of mural thrombi, blood products in atherosclerotic plaques may originate from hemorrhage through a ruptured plaque surface or from fragile newly formed vessels (neovascularization) frequently found at the base of advanced plaques. Rupture-related plaque progression due to luminal thrombosis and/or plaque hemorrhage is the most important mechanism underlying the unpredictable rapid progression of coronary lesions responsible for acute coronary syndromes. Both platelets and fibrin play a role in the dynamic thrombotic response to plaque rupture.(ABSTRACT TRUNCATED AT 250 WORDS)

Manejo del síndrome coronario agudo sin elevación del segmento ST en España. Estudio DESCARTES (Descripción del Estado de los Síndromes Coronarios Agudos en un Registro Temporal Español)

Introduccion y objetivos Se dispone de escasa informacion acerca de la situacion asistencial a escala poblacional de los sindromes coronarios agudos sin elevacion del segmento ST (SCASEST) en Espana. El objetivo es conocer la situacion de la atencion medica a los pacientes con SCASEST en Espana, desde una perspectiva representativa de la realidad estatal. Pacientes y metodo Registro prospectivo de pacientes consecutivos con SCASEST ingresados en 52 hospitales espanoles con distintos recursos cardiologicos, seleccionados al azar y que cumplieron con los criterios de control de calidad del estudio. Resultados Entre abril y mayo de 2002 se recluto a 1.877 pacientes con una edad promedio de 69 anos. El 93% tenia algun factor de riesgo y 73% antecedentes cardiovasculares. Un 76% presentaba un electrocardiograma anormal y un 53% elevacion de las troponinas. El 27% fue ingresado en una unidad coronaria o de cuidados intensivos. Se estudio al 56% de los pacientes mediante ecocardiografia, al 39% mediante una prueba de deteccion de isquemia y al 41% mediante coronariografia. En el hospital, un 88% recibio aspirina, un 81% heparina, un 37% clopidogrel, un 12% inhibidores de la glucoproteina IIb/IIIa, un 63% bloqueadores beta, un 46% inhibidores de la enzima de conversion de la angiotensina y un 52% estatinas. Se realizo revascularizacion coronaria en el 24% de los pacientes. El diagnostico final fue angina en el 54%, infarto en el 28% y otros diagnosticos en el 18%. La mortalidad fue del 3,7% a los 28 dias y del 7,8% a 6 los meses. Conclusiones DESCARTES es el primer registro representativo de la actividad asistencial en la atencion a los SCASEST en Espana. Se demuestra que, pese a que son pacientes de alto riesgo, reciben una atencion suboptima segun lo recomendado.

Prevalence, Vascular Distribution, and Multiterritorial Extent of Subclinical Atherosclerosis in a Middle-Aged Cohort The PESA (Progression of Early Subclinical Atherosclerosis) Study

Background— Data are limited on the presence, distribution, and extent of subclinical atherosclerosis in middle-aged populations. Methods and Results— The PESA (Progression of Early Subclinical Atherosclerosis) study prospectively enrolled 4184 asymptomatic participants 40 to 54 years of age (mean age, 45.8 years; 63% male) to evaluate the systemic extent of atherosclerosis in the carotid, abdominal aortic, and iliofemoral territories by 2-/3-dimensional ultrasound and coronary artery calcification by computed tomography. The extent of subclinical atherosclerosis, defined as presence of plaque or coronary artery calcification ≥1, was classified as focal (1 site affected), intermediate (2–3 sites), or generalized (4–6 sites) after exploration of each vascular site (right/left carotids, aorta, right/left iliofemorals, and coronary arteries). Subclinical atherosclerosis was present in 63% of participants (71% of men, 48% of women). Intermediate and generalized atherosclerosis was identified in 41%. Plaques were most common in the iliofemorals (44%), followed by the carotids (31%) and aorta (25%), whereas coronary artery calcification was present in 18%. Among participants with low Framingham Heart Study (FHS) 10-year risk, subclinical disease was detected in 58%, with intermediate or generalized disease in 36%. When longer-term risk was assessed (30-year FHS), 83% of participants at high risk had atherosclerosis, with 66% classified as intermediate or generalized. Conclusions— Subclinical atherosclerosis was highly prevalent in this middle-aged cohort, with nearly half of the participants classified as having intermediate or generalized disease. Most participants at high FHS risk had subclinical disease; however, extensive atherosclerosis was also present in a substantial number of low-risk individuals, suggesting added value of imaging for diagnosis and prevention. Clinical Trial Registration— URL: http://www.clinicaltrials.gov. Unique identifier: NCT01410318.