Association of the 894G>T polymorphism of the endothelial constitutive nitric oxide synthase gene with unstable angina

The 894G>T polymorphism of the endothelial constitutive nitric oxide synthase gene consists of the substitution of a guanine base by a thymine at the 894th nucleotide of the gene. An association of this polymorphism with acute coronary syndromes has been described, only when in combination with other polymorphisms of this gene. The aim of the present study was to search for an association between this polymorphism and unstable angina in a southern Brazilian population. In a case-control study, 156 patients (group 1 (N = 83): unstable angina, group 2 (N = 73): stable angina) were genotyped by PCR and digestion of the product. Univariate analysis demonstrated that the minimal luminal diameter and the degree of stenosis of the culprit lesion differed between groups (P = 0.006 and 0.005, respectively). In addition, the frequencies of the T allele and of the T allele carriers (combined TT and TG genotypes) were significantly higher in the group with unstable angina (41.6 vs 28.8 percent; P = 0.025, Pearson chi-square test, and 73.5 vs 45.2 percent; P = 0.001, Pearson chi-square test, respectively). Multivariate logistic regression showed that the frequency of the T allele carriers was the only variable with a predictive value for unstable angina, when controlled for the other variables (6.1 (95 percent CI = 2.55-14.43); P < 0.001). Thus, in a homogenous group of patients, the endothelial constitutive nitric oxide synthase 894G>T polymorphism was associated with unstable angina. We suggest that this polymorphism may be a genetic risk factor for unstable angina.

Lack of a relationship between serum ferritin levels and coronary atherosclerosis evaluated by coronary arteriography

Many clinical and epidemiological studies have demonstrated the relationship between serum ferritin and ischemic heart disease. In the present study we evaluated the relationship between coronary heart disease (CHD) and serum ferritin levels in patients submitted to coronary arteriography. We evaluated 307 patients (210 (68.7 percent) males; median age: 60 years) who were submitted to coronary angiography, measurement of serum ferritin and identification of clinical events of ischemic heart disease. Serum ferritin is reported as quartiles. Ninety-six patients (31.27 percent) had normal coronary angiography (group 1) and 211 (68.73 perce) had coronary heart disease (group 2). Of the patients with CHD, 61 (28.9 percent) had serum ferritin levels higher than 194 ng/ml (4th quartile), as opposed to only 14 (14.58 percent) of those without CHD (P = 0.0067). In the 2nd quartile, 39 patients (18.48 percent) had CHD, while 35 patients (36.46 percent) had normal coronary arteries (P = 0.00064). Multivariate analysis of the data showed that the difference between groups was not statistically significant (P = 0.33). We conclude that there is no independent relationship between coronary heart disease and increased levels of serum ferritin

Comparação da aterosclerose coronária em pacientes com infarto do miocárdio e angina do peito / Comparison of coronary heart disease extent and severity in patients with myocardial infarction and angina pectoris

OBJETIVO - Comparar a gravidade da doeça coronária e a presença de fatores de risco cardiovasculares entre pacientes com angina e infarto do miocárdio (IM). MÉTODOS - Estudaram-se 62 pacientes com IM e 129 com angina, através de cineangiocoronariografia, avaliando-se a oclusão (lesäo de 99 'por cento' ou 100 'por cento'), a severidade (escore de 0 a 5 de acordo com o número de vasos afetados) e a extensäo (3 grupos com diferentes graus de estenose). Dois observadores experientes interpretaram cegamente os angiogramas. RESULTADOS - Os pacientes com IM tiveram maior oclusão (50 'por cento' vs 13,2 'por cento'[p<0,01]), maior severidade (79 'por cento' vs 54,3 'por cento' com mais de 90 'por cento' de estenose [p<0,02]) e maior extensão (2,0 vs 0,87 [p<0,001]), mesmo quando controlados para os fatores de risco coronários clássicos e para o tempo de doença. O tabagismo foi o único fator de risco independente correlacionado com IM (P<0,01). CONCLUSÄO - Entre os pacientes estudados, a doença coronária foi maior no grupo IM, bem como a prevalência de tabagismo.

Postangioplasty restenosis: a practical model in the porcine carotid artery

Transluminal coronary angioplasty is a routine therapeutic intervention in coronary heart disease. Despite the high rate of primary success, restenosis continues to be its major limitation. Porcine models have been considered to be the most adequate experimental models for studying restenosis. One limitation of porcine models is the need for radiological guidance and the expenses involved. The objective of the present study was to adapt an experimental model of angioplasty in the porcine carotid artery that does not require radiological equipment. Eight animals were used to develop the technique of balloon injury to the common carotid artery by dissection without radiological guidance. This technique was then employed in six other animals. Under anesthesia, the left common carotid artery was dissected and incised at the carotid sinus for insertion of an over-the-wire angioplasty balloon towards the aorta. Overstretch injury of the carotid artery was performed under direct visualization. After 30 days, the arteries were excised and pressure-fixated. Uninjured carotid arteries from 3 additional animals were used as controls. A decreased luminal area associated with intimal hyperplasia and medial reaction was observed in all injured arteries. Immunohistochemistry identified the intimal hyperplastic cells as smooth muscle cells. Computerized morphometry of the ballooned segments revealed the following mean areas: lumen 2.12mm2 (+ 1.09), intima 0.22mm2 (+ 0.08), media 3.47mm2 (+ 0.67), and adventitia 1.11mm2 (+ 0.34). Our experimental model of porcine carotid angioplasty without radiological guidance induced a vascular wall reaction and permitted the quantification of this response. This porcine model may facilitate the study of vascular injury and its response to pharmacological interventions.