B vitamin therapy for homocysteine: renal function and vitamin B12 determine cardiovascular outcomes.

Therapy to lower homocysteine with B vitamins does reduce the risk of stroke, if not myocardial infarction. The apparent lack of efficacy of vitamin therapy in most of the large clinical trials was probably determined by the failure to take account of the metabolic deficiency of vitamin B12, which is very common and often missed, and by the failure to take account of impaired renal function. Metabolic B12 deficiency is present in 20% of people over 65 years of age, and in 30% of vascular patients above 70 years, so higher doses of B12 are needed in elderly patients. However, high-dose cyanocobalamin leads to accumulation of cyanide in patients with renal failure. B vitamin therapy is beneficial in patients with good renal function, but harmful in patients with significantly impaired renal function (a glomerular filtration rate <50). It seems likely that in patients with renal impairment, methylcobalamin should be used instead cyanocobalamin.

Improvement of cardiovascular risk prediction: time to review current knowledge, debates, and fundamentals on how to assess test characteristics.

Cardiovascular risk assessment might be improved with the addition of emerging, new tests derived from atherosclerosis imaging, laboratory tests or functional tests. This article reviews relative risk, odds ratios, receiver-operating curves, posttest risk calculations based on likelihood ratios, the net reclassification improvement and integrated discrimination. This serves to determine whether a new test has an added clinical value on top of conventional risk testing and how this can be verified statistically. Two clinically meaningful examples serve to illustrate novel approaches. This work serves as a review and basic work for the development of new guidelines on cardiovascular risk prediction, taking into account emerging tests, to be proposed by members of the 'Taskforce on Vascular Risk Prediction' under the auspices of the Working Group 'Swiss Atherosclerosis' of the Swiss Society of Cardiology in the future.

Interaction of smoking, hyperhomocysteinemia, and metabolic syndrome with carotid atherosclerosis: A cross-sectional study in 972 non-diabetic patients.

OBJECTIVES: Little is known about the interactions between hyperhomocysteinemia and metabolic syndrome (MetS) in individuals at risk for atherosclerosis. The aim of this study was to assess the burden of atherosclerosis in patients with MetS and hyperhomocysteinemia. METHODS: We assessed the interaction of MetS with other risk factors including hyperhomocysteinemia in 972 patients with a history of stroke, transient ischemic attack, or carotid stenosis. MetS was defined as by the International Diabetes Federation as body mass index ≥30 kg/m² and two or more of the following: hypertension, high triacylglycerides, and low high-density lipoprotein. We defined hyperhomocysteinemia as plasma total homocysteine ≥14 µmol/L. Patients with diabetes were excluded. Carotid total plaque area (TPA), a strong predictor of cardiovascular risk, was measured by carotid ultrasound. The association of TPA with MetS, and interaction with related risk factors, was assessed by multiple linear regression. RESULTS: Complete data were available on 972 non-diabetic patients. Of these, 179 (18.4%) had MetS. Patients with MetS and hyperhomocysteinemia (P < 0.001) or smoking (P = 0.02) had a higher TPA compared with those with MetS and normal plasma total homocysteine levels. In linear regression, there was a significant association of MetS (P = 0.004), hyperhomocysteinemia (P = 0.01), and smoking (P = 0.004) with increased TPA. CONCLUSIONS: Patients with MetS and smoking or hyperhomocysteinemia are at particularly high cardiovascular risk. Targeted atherosclerosis prevention should include identification and treatment of MetS, smoking, and hyperhomocysteinemia (including that due to unrecognized metabolic vitamin B12 deficiency).

Fractal dimension based carotid plaque characterization from three-dimensional ultrasound images.

Irregularity of the plaque surface associated with previous plaque rupture plays an important role in the risk estimation of stroke caused by carotid atherosclerotic lesions. Thus, the aim of this study is to develop and validate novel vulnerability biomarkers from three-dimensional ultrasound (3DUS) images by analyzing the surface morphological characteristics of carotid plaque using fractal geometry features. In the experiments, a total of 38 3DUS plaque images were obtained from two groups of patients treated with 80 mg of atorvastatin or placebo daily for 3 months respectively. Two types of 3D fractal dimensions (FDs) were used to describe the smoothness of plaque surface morphology and the roughness from intensity of 3DUS images. Student's t test showed that the two fractal features were effective for detecting the statin-related changes in carotid atherosclerosis with p < 0.00023 and p < 0.0113 respectively. It was concluded that the 3D FD measurements were effective for analyzing carotid plaque characteristics and especially effective for evaluating the impact of atorvastatin treatment. Graphical abstract ᅟ.

Adding carotid total plaque area to the Framingham risk score improves cardiovascular risk classification.

INTRODUCTION: Cardiovascular events (CE) due to atherosclerosis are preventable. Identification of high-risk patients helps to focus resources on those most likely to benefit from expensive therapy. Atherosclerosis is not considered for patient risk categorization, even though a fraction of CE are predicted by Framingham risk factors. Our objective was to assess the incremental value of combining total plaque area (TPA) with the Framingham risk score (FramSc) using post-test probability (Ptp) in order to categorize risk in patients without CE and identify those at high risk and requiring intensive treatment. MATERIAL AND METHODS: A descriptive cross-sectional study was performed in the primary care setting in an Argentine population aged 22-90 years without CE. Both FramSc based on body mass index and Ptp-TPA were employed in 2035 patients for risk stratification and the resulting reclassification was compared. Total plaque area was measured with a high-resolution duplex ultrasound scanner. RESULTS: 57% male, 35% hypertensive, 27% hypercholesterolemia, 14% diabetes. 20.1% were low, 28.5% moderate, and 51.5% high risk. When patients were reclassified, 36% of them changed status; 24.1% migrated to a higher and 13.6% to a lower risk level (κ index = 0.360, SE κ = 0.16, p < 0.05, FramSc vs. Ptp-TPA). With this reclassification, 19.3% were low, 18.9% moderate and 61.8% high risk. CONCLUSIONS: Quantification of Ptp-TPA leads to higher risk estimation than FramSc, suggesting that Ptp-TPA may be more sensitive than FramSc as a screening tool. If our observation is confirmed with a prospective study, this reclassification would improve the long-term benefits related to CE prevention.