Coronary angiography before myocardial infarction: can the culprit site be prospectively recognized?

Pregnancy-associated plasma protein-A, a marker for outcome in patients suspected for acute coronary syndrome

OBJECTIVES

To examine if pregnancy-associated plasma protein-A (PAPP-A) in patients with chest pain, could identify patients at risk for death or myocardial infarction.

DESIGN AND METHODS

Patients admitted with chest pain and both normal ECG and normal biomarkers were evaluated by serial measurement of PAPP-A. Main outcome measures were mortality and non-fatal myocardial infarction.

RESULTS

Median age of patients included (415) was 67years and 43% were women. The risk of death or non-fatal myocardial infarction after 3 months was 15% in the highest quartile of circulating PAPP-A compared with 3% in the lowest quartile (relative risk 3.7, p<0.01). Corresponding numbers after 1 year were 24% and 10% (relative risk 2.4, p=0.01).

CONCLUSION

In patients admitted with chest pain and both normal ECG and normal biomarkers PAPP-A seems to be valuable for predicting patients at high risk of death or non-fatal myocardial infarction.

Estrogen increases apoptosis in the arterial wall in a murine atherosclerosis model

OBJECTIVE

To investigate the effect of estrogen (E) on vascular apoptosis during atherosclerotic plaque formation.

DESIGN

Laboratory study using a murine atherosclerosis model.

SETTING

Academic research center.

ANIMAL(S)

Female mice homozygous for null alleles of LDL receptor (LDL-R(-/-)) in a C57BL/6 background. LDL-R(-/-) mice develop atherosclerosis in a predictable manner when fed a high cholesterol diet.

INTERVENTION(S)

Eight-week-old female LDL-R(-/-) mice (n = 68) were ovariectomized, and implanted subcutaneously with 90-day release pellets containing 0.5 mg of 17beta-estradiol (E(2)) or placebo. Four animals were evaluated at the initiation of the study. Thereafter, four animals from each group were sacrificed weekly for 8 weeks and their aortas studied.

MAIN OUTCOME MEASURE(S)

The effect of E(2) on atherosclerotic plaque development, apoptosis, and cell proliferation was examined in the aorta of ovariectomized LDL-R(-/-) mice that were fed a high cholesterol diet.

RESULT(S)

Mice treated with E(2) displayed a delay in atherosclerotic plaque formation, associated with an increase in DNA strand breaks in the arterial wall indicative of increased apoptosis, compared to placebo-treated mice. The two groups did not differ in mitotic activity.

CONCLUSION(S)

In female LDL-R(-/-) mice fed a high cholesterol diet, ovariectomy is associated with increased atherogenesis. The effect of ovariectomy on atherogenesis is reversed by E(2) treatment. In addition to delayed atherogenesis, E(2) treatment of ovariectomized LDL-R(-/-) mice results in an increase in apoptosis in the aortic wall without an effect on the mitotic activity. Our findings suggest that vascular effects of E may be in part mediated by a proapoptotic activity.

Non-invasive multislice computed tomography coronary angiography for imaging coronary arteries, stents and bypass grafts

Abstract Multislice computed tomography (MSCT) is evolving rapidly and available data suggest that MSCT coronary angiography may be a reliable and accurate non-invasive imaging modality of coronary arteries. Current generations of MSCT scanners have high sensitivity and specificity for diagnosing native coronary artery disease and coronary bypass graft occlusion. The performance of MSCT in the evaluation of stent patency is still being assessed. In comparison with conventional selective coronary angiography (SCA), MSCT is non-invasive, cheaper and it has the advantages of imaging plaque compositions as well as assessment of luminal patency. Nevertheless, the role of MSCT in the management of coronary artery disease is yet to be fully defined.

Intracoronary ultrasound in acute coronary syndromes: from characterization of vulnerable plaques to guidance of percutaneous treatment of complex stenoses

Our current knowledge on the substrate and genesis of acute coronary syndromes (ACS) results from the integration of pathological, angiographic, and intracoronary imaging techniques. To summarize briefly the current paradigm, eight differentiated stages of development of atherosclerotic lesions are currently accepted, defined not only by the cellular elements involved, but also by the appearance of sudden alterations of plaque structure and coronary thrombosis. The latter constitutes not only the dominant substrate for the most devastating manifestations of coronary artery disease, but also accelerates plaque size at a faster pace than in earlier stages. The composition of atherosclerotic plaque varies significantly along the different evolutive stages, and thus includes cellular (macrophage, smooth muscle cells) and noncellular elements (glicosaminglycan or collagen-rich cellular matrix, extracellular lipid deposits, calcification, fresh, or organized thrombus) in a varying proportion. Furthermore, a dynamic process of vessel remodeling occurs along the atherosclerotic process, resulting, in most cases, in a protective mechanism against myocardial ischemia by preserving luminal dimensions during plaque enlargement. Intravascular ultrasound (IVUS) is one of the intracoronary imaging techniques that has contributed to the understanding of these changes in man. In addition, IVUS has the potential of being a useful clinical tool for predicting the chances of future acute coronary events by identifying vulnerable plaques, of characterizing which is the culprit lesion in ACS, and in guiding revascularization procedures in the treacherous field of thrombotic coronary syndromes. In this article, we review the current evidence on the potential of IVUS imaging for fulfilling these purposes.

50th anniversary historical article. Acute coronary syndromes: the degree and morphology of coronary stenoses

In 110 patients with either stable or unstable angina, the morphology of coronary artery lesions was qualitatively assessed at angiography. Each obstruction reducing the luminal diameter of the vessel by 50% or greater was categorized into one of the following morphologic groups: concentric (symmetric narrowing); type I eccentric (asymmetric narrowing with smooth borders and a broad neck); type II eccentric (asymmetric with a narrow neck or irregular borders, or both); and multiple irregular coronary narrowings in series. For the entire group, type II eccentric lesions were significantly more frequent in the 63 patients with unstable angina (p less than 0.001), whereas concentric and type I eccentric lesions were seen more frequently in the 47 patients with stable angina (p less than 0.05). Type II eccentric lesions were also present in 29 of 41 arteries in patients with unstable angina compared with 4 of 25 arteries in those with stable angina (p less than 0.0001) in whom an "angina-producing" artery could be identified. Therefore, type II eccentric lesions are frequent in patients with unstable angina and probably represent ruptured atherosclerotic plaques or partially occlusive thrombi, or both. A temporary decrease in coronary perfusion secondary to these plaques with or without superimposed transient platelet thrombi or altered vasomotor tone may be responsible for chest pain in some of these patients with unstable angina.