Substitution of poultry and red meat with fish and the risk of peripheral arterial disease: a Danish cohort study.

PURPOSE: The aims of this study were to examine associations between substitutions of poultry and red meat intake with fish (total, lean or fatty) and the risk of peripheral arterial disease (PAD). We hypothesised that a higher intake of fish and a concomitant lower intake of poultry or red meat were associated with a lower risk of incident PAD. METHODS: We used data from a Danish cohort where middle-aged participants filled in food frequency and lifestyle questionnaires at baseline. During follow-up, we identified participants with valid diagnoses of PAD and analysed data by multivariable Cox regression analyses. Substitutions of 150 g/week of either poultry, red meat (processed or unprocessed) with 150 g/week of fish (total, lean or fatty) were explored. RESULTS: We followed the cohort (n = 54,597) for a median of 13.6 years and identified 897 cases with PAD. We found modest lower rates of PAD when intake of fish replaced a concomitant lower intake of unprocessed (HR 0.94, 95% CI 0.88-1.01) and processed red meat (HR 0.94, 95% CI 0.87-1.02). Replacing unprocessed (HR 0.89, 95% CI 0.79-1.00) or processed red meat (HR 0.88, 95% CI 0.78-1.01) with fatty fish was associated with lower rates of PAD. No associations were observed when fish intake replaced poultry or when lean fish replaced red meat. CONCLUSIONS: This study suggests that substituting red meat with fish and especially fatty fish may be associated with a lower risk of PAD, although not statistically significant. Replacing poultry with fish was not associated with the risk of PAD.

Elevated matrix metalloproteinase-9 associated with stroke or cardiovascular death in patients with carotid stenosis.

BACKGROUND: Matrix metalloproteinase-9 could exhibit an important role in the destabilization of atherosclerotic carotid plaques. We hypothesized that in patients with carotid stenosis, elevated levels of plasma matrix metalloproteinase-9 are associated with ipsilateral stroke or cardiovascular death. METHODS AND RESULTS: We followed up 207 patients with > or = 50% carotid stenosis initially for a mean of 4.4 years, during which time 53 patients developed ipsilateral stroke or died of cardiovascular causes. The cumulative incidence of ipsilateral stroke or cardiovascular death was higher in those with matrix metalloproteinase-9 above versus below the median of 41.9 ng/mL (log-rank P=0.002). Matrix metalloproteinase-9 above versus below the median had a hazard ratio for ipsilateral stroke or cardiovascular death of 1.9 (95% confidence interval [CI], 1.1 to 3.5); during extended follow-up, this remained significant until 10 years. The absolute risk of ipsilateral stroke or cardiovascular death at 4.4 years was 34% and 17% in those with matrix metalloproteinase-9 above and below the median, respectively. Elevated matrix metalloproteinase-9 and an echolucent plaque on B-mode ultrasound versus a low matrix metalloproteinase-9 and an echorich plaque had a hazard ratio for ipsilateral stroke or cardiovascular death of 4.4 (95% CI, 1.8 to 11.1) and for ipsilateral stroke of 3.3 (95% CI, 1.1 to 9.7). CONCLUSIONS: Elevated levels of matrix metalloproteinase-9 in patients with > or = 50% carotid stenosis were associated with a 2-fold risk of ipsilateral stroke or cardiovascular death. Combining elevated matrix metalloproteinase-9 and plaque echolucency was associated with a 4-fold risk for ipsilateral stroke or cardiovascular death and a 3-fold risk for ipsilateral stroke.

[Interobserver variation in ultrasonographic scanning of carotid stenosis]. / Interobservatørvariation ved UL-scanning af carotisstenose.

INTRODUCTION: Ultrasonic carotid interna scanning is today the gold standard for diagnosing carotid stenosis in patients with stroke or transient ischemic attack. The procedure of ultrasonic carotid interna scanning is not a well-defined procedure. Knowledge of the reproducibility of the method used in own department is important in order to evaluate its usefulness. MATERIAL AND METHODS: Interobserver variability of ultrasonic, duplex carotid artery scanning was examined in 68 carotid arteries in 35 patients by two experienced technologists. The two observers were compared using the kappa (kappa) statistics to analyse the agreement beyond chance. RESULTS: kappa was 0.70 (CI: 0.56-0.83) when the stenoses were categorised in the intervals 0-14%, 15-49%, 50-69%, 70-79%, 80-99% and occlusion. Categorising the stenosis in the clinically relevant intervals 0-69%, 70-79% and occlusion which are used to determine if the patient is a candidate or not to carotid endarterectomy yielded a kappa = 0.92 (CI: 0.81-1.00). DISCUSSION: Low level stenosis accounted for most variability. If state-of-the-art ultrasonic equipment and experienced technologists are used a high level of reproducibility can be achieved.

B-mode ultrasound and spiral CT for the assessment of carotid atherosclerosis.

More studies on the natural history of carotid artery plaques are needed to predict more reliably which plaque types or features are the most dangerous (see Table 2). Studies on carotid and coronary endarterectomy specimens indicate a dynamic process of rupture, thrombus formation, healing, and remodeling of the plaque. A plaque from a symptomatic patient may not show any signs of plaque rupture if the plaque has healed or evolved since the debut of symptoms. Selection of high-risk symptomatic patients with carotid atherosclerosis for medical or surgical treatment requires reliable, noninvasive, and cost-effective imaging methods. B-mode ultrasonography can be used for detection of early (IMT) as well as late (plaque morphology) atherosclerotic disease. Plaque morphology evaluation on spiral CT imaging is only for research and not yet for clinical use. Asymptomatic patients with carotid atherosclerosis hardly benefit from surgical treatment, as the minimal decrease in ischemic stroke risk is almost equal to the risk of perioperative stroke or death. A high degree of carotid stenosis measured using conventional angiography is an accepted risk factor for stroke but does not identify all vulnerable plaques. Echolucency on ultrasound B-mode imaging can be included as an important parameter in this risk stratification, as it appears to predict rupture-prone, lipid-rich plaques in the mild to severely stenotic carotid artery of a symptomatic patient. The subjective evaluation of plaque morphology on B-mode ultrasound should be complemented or substituted with objective evaluation such as videodensitometric analysis. This method is commercially available and is a relatively cheap and investigator-independent solution, but more studies are required to determine the exact contribution of echolucency to stroke risk. Furthermore, the evaluation of plaque morphology using ultrasound B-mode is still subject to large variations and observer-dependence, limiting its clinical use. In contrast, carotid IMT measurements are reliable to monitor progression and regression of early carotid disease as well as the impact of interventions. This method, however, suffers when used in severely diseased vessels where the boundaries of the IMT complex are hard to distinguish in all segments of the artery. Spiral CT imaging is a preliminary test for plaque characterization, as it primarily identifies calcification but not the more relevant lipid component. Moreover, it is time and resource demanding and involves use of both contrast and radiation, increasing the risk of allergic events and cancer. Standardization and continuous quality control are important, as are consensus agreements on how to quantify lesions (especially IMT), calibrate and standardize B-mode images and outline the plaque, and analyze data. The development of imaging methods for atherosclerotic research is currently fast and promising. This progress is most necessary, considering the very high demands for surrogate endpoints and risk markers in clinical intervention studies. Whether ultrasonic plaque characterization can be implemented in broad general clinical practice, for example, in screening of individuals at high risk of developing atherosclerosis and ischemic events, has to be based upon data from large prospective studies with long-term follow-up. IMT is already used in population screening, as in the ARIC study [9,101].

Echolucent, rupture-prone carotid plaques associated with elevated triglyceride-rich lipoproteins, particularly in women.

BACKGROUND: We tested whether fasting and postprandial triglyceride-rich lipoprotein elevations are gender specific (1) in patients with carotid artery stenosis >or=50% vs controls, and (2) in patients with echolucent, rupture-prone plaques compared with controls. METHODS AND RESULTS: We studied 66 controls and 323 patients with carotid artery stenosis >or=50%, of which 160 had echolucent plaques. Participants underwent a fat-tolerance test and carotid artery plaque evaluation with use of high-resolution B-mode ultrasound and computerized image analysis. By comparison, female cases with carotid stenosis >or=50% had higher fasting and postprandial triglyceride levels than did controls; however, this difference was not observed between male cases and controls. Fasting and postprandial very-low-density lipoprotein (VLDL) and intermediate density liprotein (IDL) cholesterol levels were elevated; low density lipoprotein (LDL) cholesterol level was unchanged, and high density lipoprotein (HDL) cholesterol level was reduced in both female and male cases vs controls. Fasting and postprandial triglyceride levels were elevated in women with echolucent plaques vs controls, but not in women with echo-rich plaques, or in men with echolucent or echo-rich plaques. Fasting and postprandial VLDL and IDL cholesterol levels were elevated, LDL cholesterol level was unchanged, and HDL cholesterol level was reduced in both female and male patients with echolucent plaques vs controls. CONCLUSIONS: Fasting and postprandial triglyceride-rich lipoproteins (but not LDLs) are elevated in patients with carotid artery stenosis of >or=50% compared with controls, and particularly identify echolucent, rupture-prone carotid plaques. These observations are more pronounced in women than in men.