RESUMEN
INTRODUCTION: Large trials have shown that angiotensin converting enzyme inhibitor (ACE-I) therapy reduces the risk of myocardial infarction and stroke. Acute vascular events are thought to be initiated by plaque rupture. Animal models of atherosclerosis show an increase in extra cellular matrix when given ACE-I therapy. ACE-I therapy could influence collagen synthesis, one of the major constituents of the atherosclerotic cap. METHODS: A nested case-control study was performed within the Huntingdon Aneurysm Screening Project. Subjects were assessed for arterial disease, drug history and smoking. Blood samples were taken for a measure of collagen synthesis, the amino-terminal propeptide of type III procollagen (PIIINP), lipid levels, iron metabolism and cotinine levels. RESULTS: Information was available for 420 subjects. Thirty-five were taking ACE-I therapy and 385 were not. Mean serum PIIINP level was 3.5 microg/l (sd 1.3 microg/l, range: 1.7-16.5 microg/l. There was a marked increase in mean collagen turnover between subjects taking ACE-I therapy compared to those not. Mean PIIINP level for cases and controls was 4.26 microg/l (95% CI: 3.73-4.79 microg/l) versus 3.61 microg/l (95% CI: 3.48-3.75 microg/l). No differences were found for patients taking other antihypertensive drugs. After adjusting for age, weight, height, lipid levels and ferritin, PIIINP levels remained significantly higher in cases than controls: 4.14 microg/l (95% CI: 3.72-4.57 microg/l) versus 3.62 microg/l (95% CI: 3.49-3.75 microg/l) (P-value 0.02). DISCUSSION: These results suggest that ACE-I therapy up-regulates collagen synthesis, and could improve plaque stabilisation. This may provide an explanation for the decrease in acute vascular events observed in patients on ACE-I therapy.
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Inhibidores de la Enzima Convertidora de Angiotensina/uso terapéutico , Colágeno Tipo III/biosíntesis , Colágeno Tipo III/efectos de los fármacos , Enfermedad Aguda , Antagonistas Adrenérgicos beta/uso terapéutico , Anciano , Aneurisma de la Aorta Abdominal/tratamiento farmacológico , Aneurisma de la Aorta Abdominal/metabolismo , Biomarcadores/sangre , Bloqueadores de los Canales de Calcio/uso terapéutico , Estudios de Casos y Controles , HDL-Colesterol/sangre , HDL-Colesterol/efectos de los fármacos , Inglaterra , Ferritinas/sangre , Ferritinas/efectos de los fármacos , Humanos , Masculino , Persona de Mediana Edad , Enfermedades Vasculares Periféricas/tratamiento farmacológico , Enfermedades Vasculares Periféricas/metabolismo , Conducta de Reducción del Riesgo , Resultado del TratamientoRESUMEN
OBJECTIVE: To examine the relationship between serum lipids and abdominal aortic aneurysms (AAA). METHODS: Two hundred and six males (>50 years) with AAA (> or =30 mm) detected in a population based screening programme were compared with 252 age-matched male controls in a nested case-control study. Smoking status, previous medical and family histories, height, weight, blood pressure, ankle brachial pressure index (ABPI) and non-fasting lipid profile were recorded. RESULTS: Cases were found to have significantly higher LDL cholesterol than controls. LDL cholesterol was an independent predictor of the risk for aneurysms in a logistic regression model adjusting for smoking status, family history of AAA, history of ischaemic heart disease, presence of peripheral vascular disease, use of lipid lowering medication and treatment for hypertension. There was a linear effect with increased levels of LDL cholesterol increasing the risk of having a small aneurysm (test for trend p=0.03). CONCLUSION: The highly significant association between LDL cholesterol and small aneurysms suggests that LDL, possibly acting via inflammatory mediated matrix degeneration, could be an initiating factor in the development of AAA. The ability of statin therapy to prevent AAA formation requires further investigation.
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Aneurisma de la Aorta Abdominal/sangre , HDL-Colesterol/sangre , LDL-Colesterol/sangre , LDL-Colesterol/fisiología , Triglicéridos/sangre , Anciano , Anciano de 80 o más Años , Aneurisma de la Aorta Abdominal/etiología , Aneurisma de la Aorta Abdominal/fisiopatología , Estudios de Casos y Controles , Humanos , Masculino , Persona de Mediana Edad , Factores de RiesgoRESUMEN
OBJECTIVES: We undertook this study to calculate the cost per life-year gained in the first round of a screening program for abdominal aortic aneurysm (AAA) and to estimate the costs in a subsequent round. METHODS: This was an intervention study, with follow-up for ruptured aneurysms. Men older than 50 years were screened for asymptomatic AAA. Outcome measures included cost per life-year saved and number of men needed to be screened to save one life. RESULTS: The incidence of ruptured AAA was 2.6 per 10,000 person- years in the screening group and 7.1 per 10,000 person-years in the control group. Screening is estimated to have prevented 10.8 ruptured AAA and 8 deaths per year, gaining 51 life-years per year for the study population, and to have reduced the incidence of ruptured AAA by 64% (95% CI, 42%-77%). Each life-year gained during the first screening round cost $1107. To save one life, 1000 men need to be screened and 5 elective operations performed. We predict that a second round of screening can be cost neutral. CONCLUSIONS: The cost-effectiveness of screening for AAA compares favorably with screening programs for other disorders in adults.
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Aneurisma de la Aorta Abdominal/diagnóstico , Aneurisma de la Aorta Abdominal/economía , Rotura de la Aorta/epidemiología , Rotura de la Aorta/prevención & control , Tamizaje Masivo/economía , Anciano , Análisis Costo-Beneficio , Costos de la Atención en Salud , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Vigilancia de la Población , Rotura Espontánea , Análisis de Supervivencia , Reino UnidoRESUMEN
INTRODUCTION: the prevalence of peripheral arterial disease (PAD) is relatively well defined for the Caucasian population. Given the susceptibility of Asians and Afro-Caribbeans to coronary heart disease and stroke respectively, and the high prevalence of cardiovascular risk factors in both groups, one would expect a high prevalence of peripheral arterial disease. METHODS: a search of MEDLINE (1966-2002) was undertaken for studies on the incidence and prevalence of PAD, abdominal aortic aneurysms (AAA) and cerebrovascular disease in different ethnic groups. RESULTS: there are very few population-based prevalence studies assessing PAD, AAA or cerebrovascular disease in non-Caucasians. A review of hospital-based series demonstrates different patterns of PAD between ethnic groups. Blacks and Asians have a tendency towards more distal occlusive disease and AAA appear to be predominantly a disease of Caucasians. It is not clear whether these studies provide a true representation of the prevalence of arterial disease in various ethnic groups or are the result of an unmet health care need. CONCLUSIONS: further studies are required to establish the prevalence, natural history and response to treatment of PAD, AAA and cerebrovascular disease in non-Caucasians. Only when this has been achieved, can clinically and cost-effective health care be delivered to affected individuals from different ethnic groups.
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Enfermedades Vasculares Periféricas/etnología , Asia/etnología , Medicina Basada en la Evidencia , Humanos , Prevalencia , Reino Unido/etnología , Estados Unidos/etnologíaRESUMEN
OBJECTIVES: To assess the accuracy of screening for abdominal aortic aneurysms (AAAs) by ultrasound (US). SETTING: An aneurysm screening programme in Huntingdon. METHODS: False negative tests were identified by tracing all patients with a ruptured aneurysm who were screened and then finding the number classified as normal on US. False positive tests were identified by calculating the number of aneurysmal aortas on US that were classified as normal on CT. Measurement variability of the infrarenal aortic diameter between US and CT was estimated. RESULTS: 14 out of 93 patients with a ruptured AAA since 1991 had been screened. No ruptured aneurysm had been classified as normal on US. All 64 patients with an AAA larger than 4.5 cm on US had their aneurysm confirmed on CT. The mean difference between CT and US measurements was 4 mm. The limit of variability between CT and US was 12 mm. CONCLUSION: No false negative scans were found using a cut off point of 3 cm as abnormal. No false positives were found if subjects with an AAA exceeding 4.5 cm were referred for further procedures. A serial US screening policy has excellent screening performance, justifying its use as a screening tool.