Mauro Amato

Cardiovascular Status of Carriers of the Apolipoprotein A-IMilano Mutant The Limone sul Garda Study

BackgroundCarriers of the apolipoprotein A-IMilano (apoA-IM) mutant present with very low plasma HDL cholesterol and moderate hypertriglyceridemia, apparently not leading to premature coronary heart disease. The objective of this study was to establish whether this high-risk lipid/lipoprotein profile is associated with structural changes in the carotid arteries and heart, indicative of preclinical atherosclerosis. Methods and ResultsTwenty-one A-IM carriers were compared with age- and sex-matched control subjects from the same kindred and with 2 series of matched subjects with primary hypoalphalipoproteinemia (HA). Structural changes in the carotid arteries were defined as the intima-media thickness (IMT) measured by B-mode ultrasound. HA subjects, both recruited among patients attending our Lipid Clinic and blood donors, showed significant thickening of the carotids (average IMT, 0.86±0.25 and 0.88±0.29 mm, respectively) compared with control subjects (average IMT, 0.64±0.12 mm); the apoA-IM carriers instead showed normal arterial thickness (average IMT, 0.63±0.10 mm). Moreover, a significantly higher prevalence of atherosclerotic plaques was found in patients and blood donors with HA (both 57%) compared with apoA-IM carriers (33%) and control subjects (21%). Echocardiographic findings and maximal treadmill ECG did not differ significantly between apoA-IM carriers and control subjects, apart from a slight increase in left ventricular end-diastolic dimension in the carriers. ConclusionsDespite severe HA, carriers of the apoA-IM mutant do not show structural changes in the arteries and heart, in contrast to HA subjects, who are characterized by a marked increase in carotid IMT and increased prevalence of atherosclerotic plaques.

Carotid Artery Intima-Media Thickness Measured by Ultrasonography in Normal Clinical Practice Correlates Well With Atherosclerosis Risk Factors

Background and Purpose The intima-media thickness (IMT) of extracranial carotid arteries determined by B-mode ultrasound is a measurable index of the presence of atherosclerosis. The ultrasonographic scan protocol and the scan reading techniques used until now to measure IMT are, however, time consuming and require the participation of specialized research centers. In this study we present a cross-sectional study of 963 patients attending the Enrica Grossi Paoletti Center in Milan, Italy, with the aim of assessing whether ultrasonographic measurements of carotid artery in routine clinical practice can yield the same results as those obtained with quantitative methods used until now in clinical trials. Methods Maximum and mean maximum IMT of carotid arteries were assessed by B-mode ultrasound with the use of the electronic caliper of the machine in real time. Results The intraobserver and interobserver variability of IMT of carotid arteries performed with the electronic caliper in real time was similar to that of quantitative processing of frozen images (coefficients of variation of intraobserver and interobserver mean maximum IMT measurements were 4.2% and 7.3%, respectively). Carotid artery IMT thus measured correlated with most of the known atherosclerosis risk factors and discriminated between patients with and without previous history of cardiovascular events. IMT was linearly related to the total number of vascular risk factors both in the whole group and after stratification of patients into 3 age classes. Conclusions These observations establish a strong correlation between B-mode imaging of carotid atherosclerosis evaluated in normal clinical practice and data provided by clinical trials and validate this simple reading technique as a means of identifying IMT as another possible risk factor in patients at high risk of vascular disease.

Functional Lecithin: Cholesterol Acyltransferase Is Not Required for Efficient Atheroprotection in Humans

Background— Mutations in the LCAT gene cause lecithin:cholesterol acyltransferase (LCAT) deficiency, a very rare metabolic disorder with 2 hypoalphalipoproteinemia syndromes: classic familial LCAT deficiency (Online Mendelian Inheritance in Man No. 245900), characterized by complete lack of enzyme activity, and fish-eye disease (Online Mendelian Inheritance in Man No. 136120), with a partially defective enzyme. Theoretically, hypoalphalipoproteinemia cases with LCAT deficiency should be at increased cardiovascular risk because of high-density lipoprotein deficiency and defective reverse cholesterol transport. Methods and Results— The extent of preclinical atherosclerosis was assessed in 40 carriers of LCAT gene mutations from 13 Italian families and 80 healthy controls by measuring carotid intima-media thickness (IMT). The average and maximum IMT values in the carriers were 0.07 and 0.21 mm smaller than in controls (P=0.0003 and P=0.0027), respectively. Moreover, the inheritance of a mutated LCAT genotype had a remarkable gene-dose–dependent effect in reducing carotid IMT (P=0.0003 for average IMT; P=0.001 for maximum IMT). Finally, no significant difference in carotid IMT was found between carriers of LCAT gene mutations that cause total or partial LCAT deficiency (ie, familial LCAT deficiency or fish-eye disease). Conclusions— Genetically determined low LCAT activity in Italian families is not associated with enhanced preclinical atherosclerosis despite low high-density lipoprotein cholesterol levels. This finding challenges the notion that LCAT is required for effective atheroprotection and suggests that elevating LCAT expression or activity is not a promising therapeutic strategy to reduce cardiovascular risk.

Carotid intima‐media thickness and markers of inflammation, endothelial damage and hemostasis

Background. Different soluble molecules involved in inflammation, endothelial damage, or hemostasis are recognized as potential cardiovascular risk markers. Studies to assess the role of these markers in the atherosclerotic process by evaluating their relationship to carotid intima‐media thickness (C‐IMT) tend to provide contrasting results. Purpose. To perform a review of studies addressing the association between C‐IMT and soluble markers and to investigate whether the observed inconsistencies could be explained by the characteristics of the patients included in different studies, for example prevalence of atherosclerotic disease (atherosclerotic burden), gender, age, or occurrence of specific vascular risk factors (VRFs). Data sources. PubMed and Embase (January 1990 to March 2006). Study selection. Articles in English reporting original cross‐sectional studies. Data extraction. Two authors independently extracted data on study design, population, sample size, ultrasonic methodology, and statistical approach. Data synthesis. Despite the marked heterogeneity of results presented in the literature, meta‐analysis established that studies showing positive associations between C‐IMT and plasma levels of C‐reactive protein (CRP) or fibrinogen are in the majority. Funnel plot analyses suggested the absence of an important publication bias. Data on the relationships between C‐IMT and other soluble markers are by contrast scanty, contradictory, or unconfirmed by multivariate (as opposed to univariate) analyses, and the freedom from publication bias here cannot be vouched for. The degree of atherosclerotic burden in the population studied does not account for the heterogeneity of findings reported. Gender, noninsulin‐dependent diabetes mellitus (NIDDM) and hypercholesterolemia influence the association between C‐IMT and CRP. Blood pressure and hypercholesterolemia influence the association between C‐IMT and fibrinogen. For all the other soluble markers considered, the number of groups was too small for this kind of statistical considerations. Limitations. Heterogeneity in ultrasound methodologies and in statistical approach limited comparability between studies. For most soluble markers, publication bias of positive results cannot be excluded. Conclusions. Only CRP and fibrinogen seem to be unequivocally related to C‐IMT. For all the other soluble markers considered, no clear‐cut conclusions can be drawn.

Effects of Timing and Extent of Smoking, Type of Cigarettes, and Concomitant Risk Factors on the Association Between Smoking and Subclinical Atherosclerosis

Background and Purpose— The purpose of this study was to evaluate the effects of timing and extent of smoking, type of cigarettes, and concomitant vascular risk factors (VRFs) on the association between smoking and carotid intima-media thickness (C-IMT) in a lipid clinic population. Methods— 1804 patients (869 men, age 21 to 85 year) participated in the study. Smoking habits were recorded and C-IMTs were measured by B-mode ultrasound. The associations of C-IMT with smoking status (never, former, and current) and with the cigarettes’ content of tar, nicotine, and carbon monoxide (alone or combined to define “light” or “regular” cigarettes) as well as the interactions between smoking status, gender, and VRFs were evaluated before and after adjustment for confounders. Results— C-IMT was highest in current smokers, lower in former, and lowest in never smokers. C-IMT of former and current smokers differed only after data adjustment for variables describing the extent and timing of smoking exposure. C-IMT was positively related to the number of pack-years (number of cigarettes smoked per day [cigarettes/d] multiplied by number of years smoked/20) in both former and current smokers. There were no differences in C-IMT between smokers of cigarettes with high or low nicotine, tar, or carbon monoxide content. Both diabetes and hypertension interacted positively with smoking in determining C-IMTs. Conclusions— In the present cross-sectional observational investigation, carried out in a cohort of patients attending a lipid clinic, consumption of light cigarettes does not reduce the atherogenic effect of smoking on C-IMT. The number of pack-years, cigarettes/d, and years of smoking are relevant covariates in evaluating the effects of smoking on vascular health. The presence of diabetes or hypertension strengthens the association between smoking and cardiovascular risk.

Normal Vascular Function Despite Low Levels of High-Density Lipoprotein Cholesterol in Carriers of the Apolipoprotein A-I Milano Mutant

Background— Carriers of the apolipoprotein A-IMilano (apoA-IM) mutant have very low plasma high-density lipoprotein cholesterol (HDL-C) levels but do not show any history of premature cardiovascular disease or any evidence of preclinical vascular disease. HDL is believed to prevent the development of vascular dysfunction, which may well contribute to HDL-mediated atheroprotection. Whether the low HDL level of apoA-IM carriers is associated with impaired vascular function is presently unknown. Methods and Results— The vascular response to reactive hyperemia, assessed by measuring postischemic increase in forearm arterial compliance, and the plasma concentration of soluble cell adhesion molecules were evaluated in 21 adult apoA-IM carriers, 21 age- and gender-matched nonaffected relatives (control subjects), and 21 healthy subjects with low HDL-C (low-HDL subjects). The average plasma HDL-C and apoA-I levels of apoA-IM carriers were remarkably lower than those of control subjects and significantly lower than those of low-HDL subjects. The postischemic increase in forearm arterial compliance in the apoA-IM carriers was 2-fold greater than in low-HDL subjects and remarkably similar to that of control subjects. Plasma soluble cell adhesion molecule levels were similar in apoA-IM carriers and control subjects but were greater in low-HDL subjects. When incubated with endothelial cells, HDL isolated from apoA-IM carriers was more effective than HDL from control and low-HDL subjects in stimulating endothelial nitric oxide synthase expression and activation and in downregulating tumor necrosis factor-&agr;–induced expression of vascular cell adhesion molecule-1. Conclusions— Despite their very low HDL levels, apoA-IM carriers do not display typical features of impaired vascular function because of an improved activity of apoA-IM HDL in maintaining endothelial cell homeostasis.

Reproducibility Validation Study Comparing Analog and Digital Imaging Technologies for the Measurement of Intima-Media Thickness

BACKGROUND AND PURPOSE New advances in B-mode imaging technologies have led to improved quality in the detection of minute changes in the surface of intima-media thickness (IMT) and plaques. The new digital systems, with increased numbers of imaging channels, multiple frequency probes, and increased microprocessing speeds, now generate images comparable to those of the analog predecessors. Can these digital systems have reproducibility comparable to that of a pure analog system? We compared the Biosound 2000II (analog) system with the Esaote AU4 (digital) system. METHODS Twenty-two subjects were chosen who had varying degrees of IMT on the far wall of the common carotid artery. Common carotid IMT was determined twice: the first time with the analog system and the second time with the digital system. With each system, replicate scans were made within 2 weeks. RESULTS The intramethod agreement was high with the analog system, with a bias between readings of -0.010+/-0.033 mm, mean absolute difference of 0.027+/-0.020 mm, repeatability coefficient of 0.067, and correlation coefficient of 0.97. The digital system provided the highest reproducibility with a bias between readings of 0.002+/-0.016 mm, mean absolute difference of 0.012+/-0.011 mm, repeatability coefficient of 0.033, and correlation coefficient of 0. 99. When the analog and digital systems were compared, the bias between readings was -0.011+/-0.024 mm with good agreement between the 2 systems; the repeatability coefficient was 0.047, with all points within +/-2 SDs of the mean difference. The mean absolute difference between the 2 measurements was 0.018+/-0.015 mm with a correlation coefficient of 0.98. CONCLUSIONS The digital system for IMT evaluation compares well with the more widely used analog system and provides a reliable technology for common carotid IMT measurement that can be applied to clinical trials.

Plasma lecithin: cholesterol acyltransferase and carotid intima-media thickness in European individuals at high cardiovascular risk

Lecithin:cholesterol acyltransferase (LCAT) is the enzyme responsible for cholesterol esterification in plasma. LCAT is a major factor in HDL remodeling and metabolism, and it has long been believed to play a critical role in macrophage reverse cholesterol transport (RCT). The effect of LCAT on human atherogenesis is still controversial. In the present study, the plasma LCAT concentration was measured in all subjects (n = 540) not on drug treatment at the time of enrollment in the multicenter, longitudinal, observational IMPROVE study. Mean and maximum intima-media thickness (IMT) of the whole carotid tree was measured by B-mode ultrasonography in all subjects. In the entire cohort, LCAT quartiles were not associated with carotid mean and maximum IMT (P for trend 0.95 and 0.18, respectively), also after adjustment for age, gender, HDL-cholesterol (HDL-C), and triglycerides. No association between carotid IMT and LCAT quartiles was observed in men (P=0.30 and P=0.99 for mean and maximum IMT, respectively), whereas carotid IMT increased with LCAT quartiles in women (P for trend 0.14 and 0.019 for mean and maximum IMT, respectively). The present findings support the concept that LCAT is not required for an efficient reverse cholesterol transport and that a low plasma LCAT concentration and activity is not associated with increased atherosclerosis.

Old and new oral anticoagulants: Food, herbal medicines and drug interactions

The most commonly prescribed oral anticoagulants worldwide are the vitamin K antagonists (VKAs) such as warfarin. Factors affecting the pharmacokinetics of VKAs are important because deviations from their narrow therapeutic window can result in bleedings due to over-anticoagulation or thrombosis because of under-anticoagulation. In addition to pharmacodynamic interactions (e.g., augmented bleeding risk for concomitant use of NSAIDs), interactions with drugs, foods, herbs, and over-the-counter medications may affect the risk/benefit ratio of VKAs. Direct oral anticoagulants (DOACs) including Factor Xa inhibitors (rivaroxaban, apixaban and edoxaban) and thrombin inhibitor (dabigatran) are poised to replace warfarin. Phase-3 studies and real-world evaluations have established that the safety profile of DOACs is superior to those of VKAs. However, some pharmacokinetic and pharmacodynamic interactions are expected. Herein we present a critical review of VKAs and DOACs with focus on their potential for interactions with drugs, foods, herbs and over-the-counter medications.

Effect of n‐3 fatty acids on carotid atherosclerosis and haemostasis in patients with combined hyperlipoproteinemia: A double‐blind pilot study in primary prevention

Background. Intake of n‐3 polyunsaturated fatty acids (n‐3 PUFA) either from natural sources or dietary supplementation is inversely associated with atherothrombosis. Aim. A double‐blind pilot study was designed to address the impact of n‐3 PUFA on atherosclerosis, haemostasis and vascular status in patients with combined hyperlipoproteinemia. Methods. Carotid intima‐media thickness (C‐IMT), texture of intima‐media complex (T‐IMC), lipids and platelet function were evaluated in 64 patients with combined hyperlipoproteinemia who received placebo or n‐3 PUFA (6 g/day) for 2 years. C‐IMT and T‐IMC were assessed by B‐mode ultrasound. Lipids and platelet function were determined by validated methods. Results. C‐IMT increased in placebo, but not in n‐3 PUFA group with respect to baseline. In contrast T‐IMC decreased in n‐3 PUFA, but not in placebo; in both cases, however, treatment effect did not reach statistical significance. A fall of triglycerides, concomitant to a rise of high‐ and low‐density lipoprotein cholesterol (HDL and LDL), was observed in the active treated group. Platelet function was significantly reduced by n‐3 PUFA. Conclusions. Results show a favourable effectiveness of n‐3 PUFA on IMT progression and T‐IMC that deserves to be confirmed in larger studies. Despite the small sample size, the beneficial effect of n‐3 PUFA on platelet function, triglycerides and HDL‐C is clearly highlighted.