Manuel Zúñiga

Lipoprotein ratios: Physiological significance and clinical usefulness in cardiovascular prevention.

Low-density lipoprotein (LDL) cholesterol concentration has been the prime index of cardiovascular disease risk and the main target for therapy. However, several lipoprotein ratios or “atherogenic indices” have been defined in an attempt to optimize the predictive capacity of the lipid profile. In this review, we summarize their pathophysiological aspects, and highlight the rationale for using these lipoprotein ratios as cardiovascular risk factors in clinical practice, specifying their cut-off risk levels and a target for lipid-lowering therapy. Total/high-density lipoprotein (HDL) cholesterol and LDL/HDL cholesterol ratios are risk indicators with greater predictive value than isolated parameters used independently, particularly LDL. Future recommendations regarding the diagnosis and treatment of dyslipidemia, including instruments for calculating cardiovascular risk or action guidelines, should include the lipoprotein ratios with greater predictive power which, in view of the evidence-based results, are none other than those which include HDL cholesterol.

Management of Dyslipidemia in the Metabolic Syndrome Recommendations of the Spanish HDL-Forum

In order to characterize the metabolic syndrome it becomes necessary to establish a number of diagnostic criteria. Because of its impact on cardiovascular morbidity/mortality, considerable attention has been focussed on the dyslipidemia accompanying the metabolic syndrome.The aim of this review is to highlight the fundamental aspects of the pathophysiology, diagnosis, and the treatment of the metabolic syndrome dyslipidemia with recommendations to clinicians.The clinical expression of the metabolic syndrome dyslipidemia is characterized by hypertriglyceridemia and low levels of high-density lipoprotein-cholesterol (HDL-C). In addition, metabolic syndrome dyslipidemia is associated with high levels of apolipoprotein (apo) B-100-rich particles of a particularly atherogenic phenotype (small dense low-density lipoprotein-cholesterol [LDL-C]. High levels of triglyceride-rich particles (very low-density lipoprotein) are also evident both at baseline and in overload situations (postprandial hyperlipidemia). Overall, the ‘quantitative’ dyslipidemia characterized by hypertriglyceridemia and low levels of HDL-C and the ‘qualitative’ dyslipidemia characterized by high levels of apo B-100- and triglyceride-rich particles, together with insulin resistance, constitute an atherogenic triad in patients with the metabolic syndrome.The therapeutic management of the metabolic syndrome, regardless of the control of the bodyweight, BP, hyperglycemia or overt diabetes mellitus, aims at maintaining optimum plasma lipid levels. Therapeutic goals are similar to those for high-risk situations because of the coexistence of multiple risk factors. The primary goal in treatment should be achieving an LDL-C level of <100 mg/dL (or <70 mg/dL in cases with established ischemic heart disease or risk equivalents). A further goal is increasing the HDL-C level to ≥40 mg/dL in men or 50 mg/dL in women. A non-HDL-C goal of 130 mg/dL should also be aimed at in cases of hypertriglyceridemia.Lifestyle interventions, such as maintaining an adequate diet, and a physical activity program, constitute an essential part of management. Nevertheless, when pharmacologic therapy becomes necessary, fibrates and HMG-CoA reductase inhibitors (statins) are the most effective drugs in controlling the metabolic syndrome hyperlipidemia, and are thus the drugs of first choice. Fibrates are effective in lowering triglycerides and increasing HDL-C levels, the two most frequent abnormalities associated with the metabolic syndrome, and statins are effective in lowering LDL-C levels, even though hypercholesterolemia occurs less frequently. In addition, the combination of fibrates and statins is highly effective in controlling abnormalities of the lipid profile in patients with the metabolic syndrome.

A very high prevalence of low HDL cholesterol in Spanish patients with acute coronary syndromes.

Total and low‐density lipoprotein cholesterol (LDL‐C) concentrations in coronary artery disease have progressively declined, although high‐density lipoprotein cholesterol (HDL‐C) has not always been evaluated. The prevalence and related factors of low HDL‐C in a cohort of Spanish patients with acute coronary syndromes (ACS) were assessed.

Prevalencia del síndrome metabólico y de sus componentes en pacientes con síndrome coronario agudo

INTRODUCTION AND OBJECTIVES A large proportion of patients with coronary disease have metabolic syndrome, although the frequency and association of its different components are not well understood. The aim of this study was to determine the prevalence of metabolic syndrome and the combination of its components in a Spanish cohort of patients with acute coronary syndrome. METHODS Clinical histories of 574 inpatients with acute coronary syndrome in 6 tertiary hospitals were reviewed and the presence of metabolic syndrome and its components determined by applying Adult Treatment Panel III criteria. In a second step, the components of the metabolic syndrome were analyzed, excluding those patients with diabetes mellitus. RESULTS The metabolic syndrome was present in 50.9% of patients and was more frequent in women than in men (66.3% vs. 47.3%; P<.001). The most prevalent component was carbohydrate metabolism disorder (85.3%), followed by low high-density lipoprotein cholesterol (HDLc) levels (80.5%). In nondiabetic patients, 34.6% had metabolic syndrome and the most prevalent component was low HDLc levels (86%), followed by high blood pressure and hypertriglyceridemia and, in fourth place, impaired fasting serum glucose levels. CONCLUSIONS The metabolic syndrome has a high prevalence in patients with an acute coronary syndrome, especially in women. The most frequent components are hyperglycemia and low HDLc levels. After excluding diabetic patients, the most prevalent diagnostic criterion of metabolic syndrome was low HDLc levels. Full English text available from: www.revespcardiol.org.

Diagnóstico de síndrome metabólico. Adecuación de los criterios diagnósticos en nuestro medio

La asociación de factores de riesgo cardiovascular es conocida desde hace muchos años. En 1923, Kylin describió la asociación de hipertensión arterial, hiperglucemia y gota. En 1936, Himsworth propuso la existencia de dos tipos de diabetes, la sensible y la resistente a la insulina. En 1956, Vague describió un tipo de obesidad androide asociada a hiperuricemia y riesgo cardiovascular. Los estudios epidemiológicos, como el realizado en la población de Framingham, han demostrado que los factores de riesgo cardiovascular en la mayoría de las ocasiones se presentan agrupados. En 1988, Reaven expuso la asociación de intolerancia a la glucosa, hipertensión, hipertrigliceridemia y disminución del colesterol de las lipoproteínas de alta densidad (cHDL) con el nombre de síndrome X, destacando su impacto en la morbilidad y mortalidad cardiovascular. Posteriormente, se han añadido otros componentes como la microalbuminuria, la esteatosis hepática no alcohólica, alteraciones procoagulantes y proinflamatorias, la hiperferritinemia y la hiperhomocisteinemia, entre otras. Sin embargo, ha sido la obesidad visceral el componente que se ha incorporado como más definitorio. El síndrome ha recibido diferentes acepciones, como síndrome de resistencia a la insulina, síndrome plurimetabólico, cuarteto de la muerte, síndrome dismetabólico cardiovascular y más recientemente, propuesto por la Organización Mundial de la Salud (OMS), síndrome metabólico (SM). Su importancia clínica y epidemiológica es la de ser un precursor identificable y corregible de la diabetes tipo 2 y de la enfermedad cardiovascular1. El SM es complejo, poligénico, multifactorial en su origen, y los criterios de definición distan de estar internacionalmente consensuados. En un reciente informe conjunto de la American Diabetes Association (ADA) y la European Association for the Study of Diabetes (EASD), se efectúa una serie de puntualizaciones sobre el concepto de SM2. Este informe recuerda que el término “síndrome” abarca un conjunto de síntomas y signos que conforman un proceso morboso y suelen obedecer a un proceso fisiopatológico único, y cuya combinación confiere un riesgo diferente del ocasionado por su suma. En relación con estos aspectos, establece determinadas críticas al reconocimiento como entidad del denominado SM y al valor clínico de su diagnóstico:

Atherogenic Ratios in Patients with Recurrent Acute Coronary Syndrome and Receiving Statin Therapy: Clinical Usefullness as Cardiovascular Predictors

Patients who have already suffered a vascular event require more and better control of cardiovascular risk factors. Different atherogenic indexes such as TC/HDLc, LDLc/HDLc, apoB/apoA-I, LDLc/apoB and non-HDLc/HDLc have been used to follow-up the patients because of their predictive capacity of the lipid profile. The aim of this study was to evaluate atherogenic ratios as a marker of the lipid residual risk in high-risk patients receiving statin therapy and to know the changes produced by previous lipid-lowering drugs treatment for a previous coronary event. The study including patients admitted to coronary care units of six Spanish tertiary hospitals for Acute Coronary Syndrome (ACS). A total of 633 ACS patients were included; of these, 478 (75.8%) had presented a myocardial infarction and 153 (24.2%) angina. A previous ACS had occurred in 43.1% of cases, and was the first episode in 56.9% of the studied patients. Among patients with known ischemic heart disease, 187 (52.2%) were receiving lipid-lowering drugs, mainly statins (182 patients, 50.7%). Of those with a first ACS, 59 (21.7%) were on lipid-lowering drugs: 55 (20.1%) statins and 4 (1.7%) fibrates. Patients with recurrent ACS had similar triglyceride and HDLc levels, but significantly lower total cholesterol and LDLc concentrations compared with those presenting the first ACS. Patients with recurrent ACS had significantly lower non-HDLc levels, TC/HDLc and LDLc/HDLc, but higher HDLc/TC and HDLc/LDLc ratios compared with first ACS patients. In patients taking statins the lipid residual vascular risk was related with the persistence of cardiovascular risk factors, and related with lipid profile with dyslipemia no-LDL dependent. So, we can conclude that the correction of lipid profile by statin is not per se sufficient to control cardiovascular risk.