Abdominal aortic aneurysm, arterial stiffening and the role of the intraluminal thrombus.

BACKGROUND: Measure of arterial stiffness could be affected by the presence of abdominal aortic aneurysm (AAA) and especially an intraluminal thrombus (ILT). We, therefore, sought to study this possible connection by measuring pulse wave velocity (PWV) and pulse wave analysis (PWA) including augmentation index adjusted to heart rate 75 (Aix75) in patients with AAA ± ILT. PATIENTS AND METHODS: PWV and PWA were measured in male patients with AAA from an ongoing Danish AAA screening trial. Information on blood pressure, medications, BMI and smoking status was obtained at inclusion. RESULTS: In total, 157 patients were included. Mean age was 73 years. Mean AAA size was 42.2 mm. Fifty-six of the patients had an intraluminal thrombus, and patients with AAA and ILT had a significantly higher Aix75 than patients with AAA but without ILT (Mean = 28.3 ± 1.4 SEM vs. 24.9 ± 0.81, p=0.027), a difference that was also significant when adjusting for AAA size, blood pressure and age. There was no difference in PWV between the groups. CONCLUSIONS: Haemodynamic properties of the aorta are affected by the presence of ILT in patients with AAA that is not explained by aortic size. Alternatively, these findings could be explained by associations between ILT and properties of the left ventricle.

Proteome analysis of human arterial tissue discloses associations between the vascular content of small leucine-rich repeat proteoglycans and pulse wave velocity.

OBJECTIVES: We hypothesized that arterial stiffness is associated with changes in the arterial protein profile, particularly of extracellular matrix components. We aimed at determining differentially expressed proteins by quantitative proteome analysis in arterial tissue from patients with different degrees of arterial stiffness. APPROACH AND RESULTS: Arterial stiffness, assessed by carotid-femoral pulse wave velocity (PWV), central blood pressure and augmentation index by pulse wave analysis were measured the day before surgery in a group of patients undergoing coronary artery bypass grafting. Protein extracts of well-defined, homogenous, nonatherosclerotic individual samples of the left mammary artery from 10 of these patients with high PWV and 9 with low PWV were compared by quantitative proteome analysis, using tandem mass tag labeling and nano-liquid chromatography mass spectrometry/mass spectrometry. Of 418 quantified proteins, 28 were differentially expressed between the groups with high and low PWV (P<0.05). Three of 7 members of the extracellular matrix family of small leucine-rich repeat proteoglycans displayed significant differences between the 2 groups (P=0.0079; Fisher exact test). Three other ECM proteins were differentially regulated, that is, collagen, type VIII, α-1 and α-2 and collagen, type IV, α-1. Several proteins related to smooth muscle cell function and structure were also found in different amounts between the 2 groups. CONCLUSIONS: Changes in the arterial amounts of small leucine-rich proteoglycans, known to be involved in collagen fibrillogenesis, and of some nonfibrillar collagens in combination with alterations in proteins related to functions of the human arterial smooth muscle are associated with arterial stiffness, as determined by PWV.

Discordant diagnoses of acute myocardial infarction due to the different use of assays and cut-off points of cardiac troponins.

OBJECTIVES: Several assays for the measurement of cardiac troponin (cTn) are available, but differences in their analytical performances may affect the diagnosis of acute myocardial infarction (MI). METHODS: A survey was conducted at all Danish departments of clinical biochemistry at hospitals receiving patients with suspected acute MI to gather information about the assay and cut-off value used. cTn was measured in blood samples from 574 patients enrolled into the Odense Chest Pain Biobank with 3 different assays: the 4th generation cTnT (cTnT(4th)), high-sensitivity cTnT (cTnT(hs); Roche Diagnostics) and cTnI (Abbott Diagnostics). To evaluate concordance, patients were dichotomised according to the 99th percentile value for each assay. Additionally, a cut-off at 50 ng/l for cTnT(hs) was used, as this is the currently employed cut-off point in Denmark. RESULTS: Using a cTnT(4th) cut-off value of >0.03 µg/l, 130 patients (23%) had potential MI. With the cTnT(hs) assay and cut-off values at 50 versus 14 ng/l, respectively, 136 (24%) versus 301 (52%) patients had potential MI. With the cTnI cut-off point, 205 patients (36%) should be considered as having had an acute MI. CONCLUSIONS: The use of different cTn assays and cut-off values may result in a discordant frequency of MI diagnoses. This makes efforts to harmonize cTn assays and cut-off levels mandatory.