Modulation of arterial reactivity using amlodipine and atorvastatin measured by ultrasound examination (MARGAUX)

Atherosclerosis 197 (2008) 420–427

Modulation of arterial reactivity using amlodipine and atorvastatin measured by ultrasound examination (MARGAUX)夽 Franc¸ois Charbonneau a , Todd J. Anderson a , Lawrence Title b , Jean Jobin c , Paul Poirier c , Thao Huyhn d , Sammy Chan e , Ann Walling d , Stuart Hutchison f , Thang Tran g , Eva Lonn h , Jean Buithieu d , Jacques Genest d,∗ a

Department of Cardiovascular Sciences and the Libin Cardiovascular Institute, University of Calgary, Calgary, AB, Canada b Dalhousie University, NS, Canada c Laval University, Que., Canada d Cardiology Division, McGill University, Montreal, Que., Canada e University of British Columbia, BC, Canada f University of Toronto, Canada g Pfizer, Canada h McMaster University, Ontario, Canada Received 4 February 2007; received in revised form 14 June 2007; accepted 21 June 2007 Available online 1 August 2007

Abstract Objective: To evaluate the effect of the calcium channel blocker amlodipine on endothelial function in normotensive patients with coronary disease taking concomitant atorvastatin therapy. Methods and results: Atorvastatin was titrated (10–80 mg/day) to maintain LDL-C < 2.5 mmol/L and patients were randomized to receive amlodipine (5–10 mg/day, n = 64) or placebo (n = 70) for 12 months. Brachial artery flow-mediated vasodilation (FMD) was assessed using vascular ultrasound. Inflammatory markers were also measured. At 12 months there was a significant decrease in mean low-density lipoprotein cholesterol (LDL-C) (4.4–2.1 mmol/L, P < 0.0001), high-sensitivity C-reactive protein (hsCRP) (3.8–2.3 mg/L, P < 0.0001) and soluble vascular cell adhesion molecule-1 (sVCAM-1) (710–665 ng/mL, P < 0.0001) for all patients, compared with baseline. Amlodipine was associated with a mean blood pressure reduction of 8/3 mmHg (P < 0.0001) whereas patients on placebo had no significant change. In the atorvastatin–placebo group, mean FMD increased (7.3–9.5%, P < 0.05) with no change in nitroglycerin-mediated dilation. No further benefit on FMD or inflammatory markers was observed with the addition of amlodipine. Conclusions: Intensive reduction of LDL-C with atorvastatin improves endothelium-dependent vasodilation and reduces markers of inflammation in patients with coronary disease. Amlodipine was not associated with a significant additional benefit on these variables. © 2007 Elsevier Ireland Ltd. All rights reserved. Keywords: Endothelial function; Cholesterol; Calcium channel blocker; Atherosclerosis; Vascular reactivity

夽 The following authors have received operating grant support and have been invited speakers and consultants, in events supported by Pfizer Canada Inc.: Franc¸ois Charbonneau, Todd J Anderson, Lawrence Title, Sammy Chan, Eva Lonn and Jacques Genest. Thang Tran is employed by Pfizer Canada Inc. ∗ Corresponding author at: McGill University Health Centre, 687 Pine Avenue West, Room M4.76, Montreal Que., Canada H3A 1A1. Tel.: +1 514 934 1934x34642; fax: +1 514 843 2813. E-mail address: [email protected] (J. Genest).

0021-9150/$ – see front matter © 2007 Elsevier Ireland Ltd. All rights reserved. doi:10.1016/j.atherosclerosis.2007.06.019

Current pharmacologic treatment for the secondary prevention of coronary artery disease (CAD) frequently involves the prescription of several concomitant therapies, particularly antihypertensives and statins (HMG-CoA reductase inhibitors). Statins have been shown to have particular benefit for vascular protection and the prevention of cardiovascular events in patients with stable CAD [1–3]. Studies have suggested that an aggressive approach to lowering low-density lipoprotein

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cholesterol (LDL-C) with statin therapy may result in even greater benefits on cardiovascular events [1–3]. The protective effect of statins is thought to be mediated, in part, through improved endothelial function [4]. Vascular endothelial dysfunction is associated with CAD and can serve as a surrogate marker of atherosclerosis [5,6]. The class of antihypertensive agents known as calcium channel blockers (CCBs) have also been associated with vascular protective effects [7–10]. The dihydropyridine CCB amlodipine slowed the progression of carotid artery atherosclerosis (compared with placebo) in the prospective randomized evaluation of the vascular effects of norvasc trial (PREVENT) [9] and of coronary atherosclerosis documented by intravascular ultrasound in the recent comparison of amlodipine versus enalapril to limit occurrences of thrombosis (CAMELOT) study [10] when compared with the angiotensin-converting enzyme (ACE) inhibitor enalapril. Several experimental studies suggest that amlodipine has a beneficial effect on endothelial function, which may be responsible for the observed reductions in atherosclerosis development [11–16]. The maintenance of vascular homeostasis by the endothelium is dependent on the bioavailability of nitric oxide (NO). Amlodipine increases endothelial nitric oxide synthase (eNOS) activity, leading to increase NO release [12]. Amlodipine may also increase NO bioavailability by inhibiting the production of oxygen-free radicals that react with NO [11,13]. However, the effect of amlodipine on endothelium-mediated dilation in human patients remains controversial [14,15]. Despite the frequent use of multiple drugs for the secondary prevention of CAD, little data are available concerning the effect of concomitant medications on endothelial function. This study (modulation of arterial reactivity using amlodipine and atorvastatin measured by ultrasound examination [MARGAUX]) was designed to investigate the effect of amlodipine therapy on endothelial function in normotensive patients with documented CAD who was concomitantly treated with atorvastatin (titrated to achieve LDL-C <2.5 mmol/L).

1. Methods 1.1. Patient population The MARGAUX study was a prospective, randomized, double-blind, placebo-controlled study carried out between November 8, 2000 and January 16, 2004. Patients, aged 30–75 years, were recruited from nine centers across Canada. All patients had documented CAD, defined by: coronary stenosis of >70% on angiography; myocardial ischemia; or history of myocardial infarction. Patients were excluded if: they had blood pressure (BP) ≤100/60 mmHg or ≥150/95 mmHg; LDL-C <3.2 mmol/L; or triglycerides ≥4.5 mmol/L, at baseline. Other exclusion criteria included: acute coronary syndrome, revascularization or a cerebrovas-

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cular event in the preceding 3 months; significant renal dysfunction (serum creatinine >200 ␮mol/L); uncontrolled diabetes (HbA1c >0.10); severe aortic stenosis or chronic atrial fibrillation; and contraindication to statin or CCB therapy. During the study patients were not permitted to take: other lipid-lowering agents or other CCBs; immunosuppressive agents; or any compounds that may interfere with the action of the study drugs. This study was approved by the appropriate institutional ethics committees and all participants gave their written informed consent. 1.2. Study protocol Eligibility was assessed at a screening visit 6 weeks prior to the baseline visit and at baseline. At the screening visit patients previously taking lipid-lowering agents and/or CCBs were asked to discontinue these medications and were placed on single-blind, double-placebo treatment for 6 weeks (initial washout). At baseline, patients were randomized to single-blind atorvastatin 10 mg per day and to double-blind amlodipine 5 mg per day or placebo (Fig. 1). At 4 weeks, atorvastatin was increased to 80 mg per day (unless LDL-C was <2.5 mmol/L) and amlodipine to 10 mg per day (unless BP was <90/60 mmHg). After 12 months treatment patients underwent a final washout phase, during which they received a single-blind, double-placebo treatment for 2 months. 1.3. Efficacy variables The primary efficacy variable was endothelial function, as assessed by brachial artery vasomotor response to hyperemia (flow-mediated dilation [FMD]). Secondary efficacy variables were levels of plasma lipids (including: total cholesterol, high-density lipoprotein cholesterol [HDL-C] and triglycerides, measured at each recruiting institution; calculated-LDL-C; and apolipoprotein B [apoB], measured at the Special Biochemistry Core laboratory [Royal Victoria Hospital, Montreal, QC]) and inflammatory markers (including: high-sensitivity C-reactive protein [hsCRP], measured using a validated immunoturbidometric method [17]; tissue plasminogen activator [tPA], soluble intercellular adhesion molecule (sICAM)-1, soluble vascular cell adhesion molecule [sVCAM]-1, sE-selectin and sP-selectin, measured by enzyme-linked immunosorbent assay [ELISA] [R&D, Mississauga, Ontario]). Safety was assessed at each visit and all adverse events were recorded. All efficacy assessments were carried out following a 12 h fast and were performed at baseline and at 3, 12 and 14 months (Fig. 1). Plasma lipids and BP were measured at all patient visits (1, 3, 6, 9, 12 and 14 months). 1.4. Flow-mediated dilation High-resolution ultrasound examination of FMD was performed by upper-cuff occlusion in selected institutions with

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previous experience of this technique. A standardized image acquisition protocol was used in all centers according to the guidelines recommended by Corretti et al. [18] Imaging was performed before and after administration of sublingual nitroglycerin (please see supplementary material for protocol). Images were analyzed at a core laboratory (Vasometrix, Montreal, QC). 1.5. Brachial artery analysis End-diastolic freeze frames were digitized at regular intervals (5 s) and the arterial diameters measured using Dynamic Endothelial Assessment [DEA] software (Calgary, Canada), calibrated for each imaging center. Resting and post-nitroglycerin diameters were calculated as the median from 9 frames acquired over 60 s. Postreactive hyperemic maximal diameter was calculated as the median of the five consecutive frames with the highest diameter sum between 45 and 120 s after cuff release. Intra- and inter-observer variability for FMD measurement using DEA on the same digitized images was 0%. 1.6. Statistical analysis Values for the intent-to-treat (ITT) population (defined as patients who provided a baseline efficacy assessment and at least one post-randomization assessment) are presented as mean (±standard deviation [S.D.]) for continuous variables and as absolute numbers (%) for categoric variables. Calculations were performed using Statistical Analysis System (SAS, Version 8.2) software (please see supplementary material for statistical analyses used).

2. Results 2.1. Baseline characteristics Of 207 patients screened, 144 were randomized to receive study medication, 134 were included in the ITT population and 118 patients completed the trial (atorvastatin–amlodipine group, n = 55; atorvastatin–placebo group, n = 63) (Fig. 1, online supplementary material). Baseline characteristics for the ITT population are presented in Table 1. There were more diabetic patients in the atorvastatin–placebo group than the atorvastatin–amlodipine group, but BP (Table 1) and resting brachial artery diameter (Table 1, online supplementary material) were similar between both groups. At baseline, there was no significant difference in lipid measurements between the two groups except for HDL-C, which was slightly higher in the atorvastatin–amlodipine group (P = 0.04) (Table 2). Prior to the study, 91.4% of patients in the atorvastatin–amlodipine group and 94.5% in the atorvastatin–placebo group had received treatment for dyslipidemia and 55.7% and 56.2% of patients in the atorvastatin–amlodipine and atorvastatin–placebo groups, respectively, received antihypertensive medications. During the study, 98.6% of patients in the atorvastatin–amlodipine group and all patients in the atorvastatin–placebo group reported taking concomitant medications. The most common concomitant medications reported were anti-inflammatory analgesics, which were taken by 92.9% of patients in the atorvastatin–amlodipine group and 100% of patients in the atorvastatin–placebo group. In the atorvastatin–amlodipine and atorvastatin–placebo groups, 67.1% and 71.2% of patients, respectively, took beta-adrenoceptor blocking drugs and 52.9% and 61.6% of patients, respectively,

Fig. 1. Study design.

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Table 1 Baseline characteristics of the ITT population Variables

Atorvastatin–amlodipine (n = 64)

Atorvastatin–placebo (n = 70)

All patients (n = 134)

Mean age, years (±S.D.) Male/female (n) BMI (kg/m2 ) (±S.D.) Diabetes mellitus, n (%) History of smoking, n (%) Previous MI, n (%) Mean BP, mmHg (±S.D.)

58.5 (±8.4) 55/9 28.1 (±3.1) 2 (3) 52 (81) 36 (56) 127 (±15)/79 (±9)

56.2 (±8.7) 60/10 28.9 (±3.8) 10 (14) 59 (84) 43 (61) 128 (±14)/79 (±8)

57.3 (±8.6) 115/19 28.5 (±3.5) 12 (9) 111 (83) 79 (59) 128 (±15)/79 (±9)

BMI, body mass index; MI, myocardial infarction.

took other antihypertensive agents in addition to the study drug. At 12 months, 70% of the atorvastatin–amlodipine group were taking the maximum dose of both drugs and 9% were taking atorvastatin 80 mg and amlodipine 5 mg per day. In the atorvastatin–placebo group, 74% were taking atorvastatin 80 mg and placebo. Median treatment duration was 355.5 days in the atorvastatin–amlodipine group and 357.0 days in the atorvastatin–placebo group. 2.2. Flow-mediated dilation For the whole population, FMD increased from 7.7% (±4.0) at baseline to 8.8% (±4.8) at 12 months (P < 0.05) and continued to increase during the final washout phase to a maximum of 10.2% (±4.6) at 14 months (a relative increase of 32% compared with baseline [P < 0.0001]). At baseline, FMD was slightly higher in the atorvastatin–amlodipine group (8.1% [±4.2]) compared with the atorvastatin–placebo group (7.3% [±3.9]) although the difference was not statistically significant (P = 0.2) (Fig. 2A). In patients randomized to atorvastatin–placebo, mean FMD increased from baseline by 18% (P < 0.05) within 3 months of treatment and remained significantly improved by the end of the study, including the washout period. In contrast, FMD in the atorvastatin–amlodipine group tended to decrease in the first 3 months (P < 0.01 compared with baseline) and was similar to baseline after 12 months of treatment. After the 2 months washout period, FMD increased by 36% compared with baseline (P ≤ 0.001) for patients who had received atorvastatin–amlodipine and tended to be higher in the

amlodipine group compared with placebo (11.0% [±5.3] versus 9.5% [±3.8], respectively, P = 0.056). There was no significant change for either treatment group in endotheliumindependent vasodilation with nitroglycerin at any time during the study (Fig. 3) (also Table 1, online supplementary material). Assessments for ethnicity- or sex-based differences were not undertaken. While resting brachial artery diameters were comparable between treatment groups at baseline, there was a significant difference at 12 months, primarily related to a reduction in the atorvastatin–placebo group (4.05 mm [±0.72] to 3.84 mm [±0.56], P < 0.05). After 2 months washout, brachial artery diameters were again similar (Fig. 2B) (also Table 1, online supplementary material). No significant correlation was established between change in FMD and change in hsCRP (Pearson’s correlation coefficient = 0.023, P = NS), or between change in FMD and change in LDL-C (Pearson’s correlation coefficient = −0.149, P = NS). 2.3. Changes in lipids and blood pressure Among the whole patient population, there was a sustained 50% reduction in LDL-C (with 81% of patients achieving LDL-C <2.5 mmol/L at 12 months), a 43% reduction in apoB and a 30% reduction in triglycerides, observed at both 3 and 12 months of treatment (P < 0.0001 in all cases). These variables returned to near baseline levels after the final 2 months washout period. At 12 months, the group receiving atorvastatin–amlodipine had slightly higher total cholesterol, LDL-C and apoB levels than those given

Table 2 Lipid, lipoprotein lipids and apolipoprotein B levels at baseline, 12 months and after 2 months washout Baseline

Total cholesterol, mmol/L (±S.D.) Triglycerides, mmol/L (±S.D.) LDL-C, mmol/L (±S.D.) HDL-C, mmol/L (±S.D.) Apo B, g/L (±S.D.) * **

P < 0.0001 versus baseline. P < 0.05 versus atorvastatin–placebo.

12 months

Washout

Atorvastatin– placebo (n = 64)

Atorvastatin– amlodipine (n = 70)

Atorvastatin– placebo (n = 64)

Atorvastatin– amlodipine (n = 70)

Atorvastatin– placebo (n = 64)

Atorvastatin– amlodipine (n = 70)

6.4 (±1.2) 2.1 (±0.9) 4.3 (±1.1) 1.1 (±0.3) 1.4 (±0.3)

6.4 (±1.0) 1.9 (±0.8) 4.4 (±0.8) 1.3 (±0.4)** 1.3 (±0.2)

3.8 (±0.6)* 1.5 (±0.8)* 2.0 (±0.4)* 1.1 (±0.3) 0.7 (±0.1)*

4.1 (±0.6)*,** 1.3 (±0.6)* 2.3 (±0.5)*,** 1.2 (±0.3) 0.8 (±0.1)*,**

6.3 (±1.1) 2.1 (±1.2) 4.2 (±1.0) 1.1 (±0.3) 1.4 (±0.3)

6.3 (±1.1) 1.9 (±0.9) 4.3 (±1.0) 1.2 (±0.3) 1.3 (±0.3)

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atorvastatin–placebo (Table 2). At 12 months, mean BP was reduced from baseline by 8 (±2)/3 (±1) mmHg (P < 0.0001) for patients in the atorvastatin–amlodipine group whereas BP for patients in the atorvastatin–placebo group did not change significantly. Data for BP and LDL-C reduction and goal attainment in each treatment group have been reported in more detail elsewhere [19]. In order to assess the impact of baseline BP on the FMD, we extracted a subgroup of subject with BP ≥ 140/90 or BP ≥ 130/80 for diabetes subjects at baseline and analyzed the FMD change. Overall, 39 subjects were classified as subject with high pressure at baseline. We performed an analysis of covariance (ANCOVA) adjusting for baseline FMD, center and baseline BP. The adjusted mean score (LSMeans) differs only slightly with the ones obtained from the model without BP adjustment suggesting that BP were well balanced between the two treatment groups and has marginal impact on the change in FMD. The effect of smoking status at baseline was examined. Interestingly, ex-smokers and current smokers (n = 37 and 15 in the atorvastatin/amlodipine group and n = 42 and 14 in the amlodipine/placebo groups) had a slightly better improvement that non-smokers (n = 12 in the atorvastatin/amlodipine group and n = 11 in the atorvastatin/placebo group). The number of non-smokers or current smokers is too small to draw conclusions. The effect of diabetes at baseline was then examined. When analyzed separately, diabetic patients had similar effects on FMD as non-diabetic subjects. The presence of diabetes did not influence FMD in the present study. 2.4. Inflammatory markers Fig. 2. FMD (A) and resting brachial artery diameter (B) according to treatment group *P < 0.05 versus baseline, † P < 0.05 versus atorvastatin–amlodipine, ‡ P < 0.0001 versus baseline, P = 0.056 versus atorvastatin–placebo.

Among the whole population hsCRP was reduced during active treatment (by 40% at 12 months, P < 0.0001); this was followed by an increase during the washout phase. In contrast, sVCAM-1 showed a sustained reduction during the active phase (6.4% at 12 months, P < 0.0001) and continued to decrease during the final washout phase (Table 2, online supplementary material). There were no consistent and significant differences in markers of vascular inflammation between the atorvastatin–placebo and atorvastatin–amlodipine groups. 2.5. Adverse events

Fig. 3. Nitroglycerin-induced dilation according to treatment group. No differences between groups were observed.

Treatment-related adverse events were reported by 50.0% of patients in the atorvastatin–amlodipine group and 17.8% in the atorvastatin–placebo group. The most common treatment-related adverse event was peripheral edema (22.9% of patients in the atorvastatin–amlodipine group and 1.4% in the atorvastatin–placebo group). Ten patients in the atorvastatin–amlodipine group discontinued due to treatment-related adverse events, as did one patient who had received atorvastatin plus placebo.

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Adverse events were recorded according to pre-established criteria by study investigators and coordinators. Mild, reversible peripheral (ankle) edema was reported in approximately 23% of patients on amlodipine (versus <2% on placebo). This represented the majority of side effects due to amlodipine. Asthenia (n = 4 (5.7%); myalgias (n = 4 (5.7%); dizziness (n = 4 (5.7%) and rash (n = 4 (5.7%) were seen more often than in placebo. Other side effects, including headaches, nausea, etc. were not significantly different between amlodipine and placebo.

3. Discussion The MARGAUX study demonstrated that intensive reduction of LDL-C to <2.5 mmol/L with atorvastatin resulted in improved endothelium-dependent vasodilation and a decrease in the markers of vascular inflammation, hsCRP and sVCAM-1. The addition of the CCB amlodipine did not further improve endothelial function during the study period. Treatment-related adverse events were similar to those reported in trials of each agent taken in isolation or concomitantly [10,20–23]. This study confirms previous reports that have shown an improvement in endothelium-dependent vasomotion with statin therapy [24,25]. While previous studies have shown improved brachial FMD with statin therapy in patients with coronary disease [26], the current study is among the largest to date. All patients received a background of atorvastatin with a LDL-C goal of <2.5 mmol/L, a level recently associated with a marked reduction in clinical events [3]. Among the whole population the mean reduction in LDL-C was 50% and this was associated with improved brachial FMD after 1 year of therapy. A significant increase in FMD was seen by 3 months in the atorvastatin–placebo group, confirming previous studies that demonstrate a rapid effect of this agent [24,27]. The inflammatory protein hsCRP has been associated with atherosclerosis development and serves as a marker of risk [28]. Two recent studies have suggested that reductions in hsCRP are associated with the beneficial effects of statins on either coronary atherosclerosis progression or cardiovascular events [29,30]. Consistent with these reports, hsCRP was reduced by 40% by 1 year. However, there was no relationship between the change in hsCRP and improvement in FMD. Previous work by our group has similarly demonstrated no relationship between hsCRP and FMD in a cohort of healthy patients [31]. Of the other inflammatory markers measured, a small, but statistically significant, reduction was observed in the leukocyte adhesion integrin, sVCAM1. This supports data from some previous studies of statin therapy that showed a similar reduction [4]. Surprisingly, this reduction continued during the final washout phase of the study indicating that atorvastatin may have effects on endothelial function that persist in the absence of the active drug.

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Given the lack of correlation between change in lipids, hsCRP, or other inflammatory markers and endothelial function, it cannot be ascertained from the current data how statins improve endothelial health. However, evidence suggests that direct vascular responses may contribute to the favorable effects of statins on endothelial function independent of lipidlowering [4,32,33]. This study explored the benefits of the addition of the CCB amlodipine to patients with optimal control of LDL-C with statin therapy. Amlodipine did not result in a further increase in FMD compared with the placebo group. This is consistent with a previous study from our group in which amlodipine (5 mg) did not improve endothelial function whereas improvement was demonstrated with an ACE inhibitor [34]. Ghiadoni et al. obtained similar results in hypertensive patients, reporting no improvement in brachial FMD with either nifedipine or amlodipine treatment [14]. In contrast, two smaller studies, measuring endotheliumdependent peripheral blood flow responses with strain-gauge plethysmography, showed improved endothelial responses following treatment with nifedipine, one in patients with hypertension [35], the other in hypercholesterolemic patients [36]. For patients with CAD, the evaluation of nifedipine and cerivastatin on recovery of coronary endothelial function (ENCORE) study investigators reported a modest improvement in the endothelial response of the coronary conduit arteries after 6 months therapy with nifedipine over placebo. Interestingly, this improvement was attenuated in the group randomized to the combination of nifedipine and cerivastatin [37]. The differences observed between studies may be a result of the choice of methodology and vascular bed studied. It is also possible that an effect of CCBs on basal tone may affect interpretation of the FMD response. In the current study the improvement of FMD to near normal levels by atorvastatin may have masked the effect of amlodipine. Further studies employing a crossover design are needed to resolve this issue. Amlodipine may also have a greater benefit on FMD in patients whose BP is uncontrolled at baseline. Notably there was a statistically significant decrease in resting brachial artery diameter in the atorvastatin–placebo group and a non-significant increase for those receiving amlodipine. At baseline and after the washout period brachial artery diameters were similar between the two groups (Fig. 2B) (also Table 2, online supplementary material). Increased brachial artery diameter in response to statin therapy has not been widely reported. However, a careful evaluation of previous statin trials does demonstrate a trend for a decrease in the baseline diameter [4]. FMD has been shown to be inversely related to resting brachial artery diameter [38] and it is possible that the treatment-related changes in diameter observed may have masked a potential effect of amlodipine on brachial reactivity. Despite the increase in LDL-C during the final washout in the atorvastatin–amlodipine group, an improvement was seen in FMD for these patients. This may be related to the asso-

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ciated decrease in brachial artery diameter that was seen in this group, which may reflect a washout of the drugs vasodilatory properties. However, given that FMD tended to be higher after the washout period in the atorvastatin–amlodipine group versus the atorvastatin–placebo group, we cannot rule out a delayed effect of amlodipine on endothelial function only noted after 2 months of drug withdrawal that may be related to the high lipophilicity and membrane localization of amlodipine [16,39]. In order to eliminate the effect of resting brachial artery diameter variability on FMD, it has been proposed to use the ratio FMD/(nitroglycerin-mediated dilation) [40]. When this ratio was applied to our data, no significant difference was seen in our results (data not shown). It is a limitation of the study that, for ethical reasons, patients were permitted to take non-CCB antihypertensives alongside study medications, as the potential effect of these drugs on endothelial function cannot be controlled for. A comparison study with a matched group of healthy participants could be carried out in order to eliminate the possibility that prior and concomitant treatments influenced the responses seen here. In patients with coronary disease and normal BP, intensive reduction of LDL-C results in favorable effects on endothelium-dependent vasodilation and markers of inflammation. There was no significant additional benefit of amlodipine on these variables, but a modest effect on endothelial function cannot be excluded due to the vasodilatory effects of amlodipine on resting brachial diameter.

Acknowledgements This work was supported by a grant from Pfizer Canada, Inc. We thank Shiona Dempster, Jerome Vincent and Denis Lavertu for technical assistance.

Appendix A. Supplementary data Supplementary data associated with this article can be found, in the online version, at doi:10.1016/j.atherosclerosis. 2007.06.019.

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