Antonio Silvestro

Endothelial dysfunction and cardiovascular risk prediction in peripheral arterial disease: additive value of flow-mediated dilation to ankle-brachial pressure index.

Background—Endothelial dysfunction plays a key role in atherogenesis. We prospectively investigated the impact of noninvasive measurement of endothelial function on cardiovascular risk in peripheral arterial disease (PAD). The study was specially aimed at assessing whether brachial artery flow-mediated dilation (FMD) added to the predictive value of ankle-brachial pressure index (ABPI). Methods and Results—Of 131 patients monitored for a mean of 23±10 months, 18 had a coronary event, 12 a cerebrovascular event, and 9 a peripheral event. The median FMD was lower in patients with an event than in those without (5.8% versus 7.6%, P <0.05), whereas vasodilation to nitroglycerin was similar in the two groups. The cardiovascular event rate was higher in patients with FMD below the median versus those with FMD above the median (P <0.001 by log-rank test). In a Cox proportion hazard model, independent predictors of events were FMD below the median (P <0.01), ABPI below the median (P <0.01), and previous stroke (P <0.02). Similar results were obtained when peripheral events were excluded from the analysis. Below-median ABPI and FMD combined was more accurate in predicting risk (relative risk [RR] 13.0; 95% CI, 3.0 to 56.2; P <0.01) than ABPI (RR, 6.4; 95% CI, 1.4 to 29.1; P <0.02) and FMD (RR, 4.8; 95% CI, 1.1 to 23.3; P <0.05) alone. Conclusions—A low brachial artery FMD is an independent predictor of cardiovascular risk in patients with PAD and adds to the prognostic value of ABPI, which is currently the most powerful prognostic indicator in PAD.

Everolimus-eluting stent versus bare-metal stent in ST-segment elevation myocardial infarction (EXAMINATION): 1 year results of a randomised controlled trial

BACKGROUND Everolimus-eluting stent (EES) reduces the risk of restenosis in elective percutaneous coronary intervention. However, the use of drug-eluting stent in patients with ST-segment elevation myocardial infarction (STEMI) is still controversial. Data regarding the performance of second-generation EES in this setting are scarce. We report the 1-year result of the EXAMINATION (clinical Evaluation of the Xience-V stent in Acute Myocardial INfArcTION) trial, comparing EES with bare-metal stents (BMS) in patients with STEMI. METHODS This multicentre, prospective, randomised, all-comer controlled trial was done in 12 medical centres in three countries. Between Dec 31, 2008, and May 15, 2010, we recruited patients with STEMI up to 48 h after the onset of symptoms requiring emergent percutaneous coronary intervention. Patients were randomly assigned (ratio 1:1) to receive EES or BMS. Randomisation was in blocks of four or six patients, stratified by centre and centralised by telephone. Patients were masked to treatment. The primary endpoint was the patient-oriented combined endpoint of all-cause death, any recurrent myocardial infarction, and any revascularisation at 1 year and was analysed by intention to treat. The secondary endpoints of the study included the device-oriented combined endpoint of cardiac death, target vessel myocardial infarction or target lesion revascularisation, and rates of all cause or cardiac death, recurrent myocardial infarction, target lesion or target vessel revascularisation, stent thrombosis, device and procedure success, and major and minor bleeding. This trial is registered with ClinicalTrials.gov, number NCT00828087. FINDINGS Of the 1504 patients randomised, 1498 patients were randomly assigned to receive EES (n=751) or BMS (n=747). The primary endpoint was similar in both groups (89 [11·9%] of 751 patients in the EES group vs 106 [14·2%] of 747 patients in the BMS group; difference -2·34 [95% CI -5·75 to 1·07]; p=0·19). Device-oriented endpoint (44 [5·9%] in the EES group vs 63 [8·4%] in the BMS group; difference -2·57 [95% CI -5·18 to 0·03]; p=0·05) did not differ between groups, although rates of target lesion and vessel revascularisation were significantly lower in the EES group (16 [2·1%] vs 37 [5·0%], p=0·003, and 28 [3·7%] vs 51 [6·8%], p=0·0077, respectively). Rates of all cause (26 [3·5%] for EES vs 26 [3·5%] for BMS, p=1·00) or cardiac death (24 [3·2%] for EES vs 21 [2·8%] for BMS, p=0·76) or myocardial infarction (10 [1·3%] vs 15 [2·0%], p=0·32) did not differ between groups. Stent thrombosis rates were significantly lower in the EES group (4 [0·5%] patients with definite stent thrombosis in the EES group vs 14 [1·9%] in the BMS group and seven [0·9%] patients with definite or probable stent thrombosis in the EES group vs 19 [2·5%] in the BMS group, both p=0·019). Although device success rate was similar between groups, procedure success rate was significantly higher in the EES group (731 [97·5%] vs 705 [94·6%]; p=0·0050). Finally, Bleeding rates at 1 year were comparable between groups (29 [3·9%] patients in the EES group vs 39 [5·2%] in the BMS group; p=0·19). INTERPRETATION The use of EES compared with BMS in the setting of STEMI did not lower the patient-oriented endpoint. However, at the stent level both rates of target lesion revascularisation and stent thrombosis were reduced in recipients of EES. FUNDING Spanish Heart Foundation.

Endothelial dysfunction in peripheral arterial disease is related to increase in plasma markers of inflammation and severity of peripheral circulatory impairment but not to classic risk factors and atherosclerotic burden

OBJECTIVE We undertook this study to evaluate in patients with peripheral arterial disease (PAD) the relationship of endothelial dysfunction, which is directly related to progression and clinical complications of atherosclerosis, with variables including classic risk factors, inflammation, severity of peripheral circulatory impairment, and atherosclerotic burden. METHODS This cross-sectional study included outpatients seen in an academic angiologic unit. Eighty-eight consecutive patients with PAD (ankle/brachial index [ABI] < 0.90) were studied. The control group consisted of 30 age-matched and sex-matched healthy subjects. Main outcome measures were endothelial function in the form of brachial artery flow-mediated dilation (FMD), plasma levels of C-reactive protein (CRP) and fibrinogen, severity of PAD according to ABI, and atherosclerotic burden, ie, atherosclerosis in one leg or in two or more other sites. RESULTS Compared with patients with FMD greater than 6.2% (ie, 5th percentile of FMD in control subjects), patients with FMD less than 6.2% had a similar prevalence of classic risk factors but higher median levels of CRP (1.6 vs 6.0 mg/L; P <.01) and fibrinogen (200 vs 374 mg/dL; P <.01). The two inflammatory markers were negatively correlated with FMD (P <.01). ABI was higher in patients with FMD greater than 6.2% than in those with worse endothelial function (0.72 +/- 0.15 vs 0.62 +/- 16; P <.01); there was no difference with respect to atherosclerotic burden. Multivariate analysis showed that the association of CRP, fibrinogen, and ABI with FMD less than 6.2% was unrelated to classic risk factors. In a second model, which included CRP, fibrinogen, and ABI, all three variables were independently related to FMD less than 6.2%. CONCLUSION Inflammation and severity of circulatory impairment are implicated in the pathophysiology of dysfunctional endothelium in PAD.

Vitamin C prevents endothelial dysfunction induced by acute exercise in patients with intermittent claudication

In patients with intermittent claudication, exercise is associated with a marked increase in oxidative stress, likely responsible for systemic endothelial perturbation. In 31 claudicant patients, we assessed the effect of vitamin C administration on the acute changes induced by maximal and submaximal exercise in endothelium-dependent, flow-mediated dilation (FMD), and in plasma levels of thiobarbituric acid-reactive substances (TBARS) and soluble intercellular adhesion molecule-1 (sICAM-1). In 16 claudicants, maximal exercise reduced FMD (from 8.5+/-0.9 to 3.7+/-0.8%, P<0.01), and increased plasma levels of TBARS (from 1.93+/-0.06 to 2.22+/-0.1 nmol/ml, P<0.02) and of sICAM-1 (from 282+/-17 to 323+/-19 ng/ml, P<0.01). In eight of these patients, randomized to vitamin C, exercise-induced changes in FMD and biochemistry were abolished. This beneficial effect was not observed in the eight patients randomized to saline. In 15 patients, who walked until the onset of claudication pain (submaximal exercise), and in ten control subjects, who performed maximal exercise, no changes were observed with exercise. Thus, in claudicants, vitamin C prevents the acute, systemic impairment in endothelial function induced by maximal exercise. This finding provides a rationale for trials investigating antioxidant therapy and cardiovascular risk in patients with intermittent claudication.

Inflammatory status and endothelial function in asymptomatic and symptomatic peripheral arterial disease.

Peripheral arterial disease (PAD) is a predictor of cardiovascular risk. However, it is unknown whether PAD severity influences inflammatory status and endothelial function, which play a major role in atherosclerosis. Accordingly, we measured brachial artery flow-mediated dilation (FMD), and plasma levels of several inflammatory markers in 15 control subjects, and 19 asymptomatic and 19 symptomatic PAD patients. Each symptomatic patient was matched to an asymptomatic patient for age, sex, risk factors, presence of cardiovascular disease, and pharmacological treatments. Asymptomatic patients had similar inflammatory profiles as controls, but lower median FMD (11.7% vs 8.5%, p < 0.01). Compared with asymptomatic patients, symptomatic patients had higher median C-reactive protein (1.5mg=l vs 6.0 mg=l, p < 0.05) and interleukine-6 (1.5 pg=ml vs 3.5 pg=ml, p < 0.05), and lower FMD (8.5% vs 5.1%, p < 0.01). In the 38 PAD patients, the ankle=brachial pressure index correlated positively with FMD (p < 0.01), and negatively with C-reactive protein (p < 0.05), soluble intercellular adhesion molecule-1 (p < 0.05) and soluble vascular cell adhesion molecule-1 (p < 0.05). Thus, in PAD, endothelial function and inflammatory status are related to the severity of the circulatory impairment. This finding may contribute to the explanation of the increasingly poor prognosis with increased PAD severity.

Adhesion molecules and cardiovascular risk in peripheral arterial disease Soluble vascular cell adhesion molecule-1 improves risk stratification

Although intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) play a relevant role in atherosclerosis, little is known about the prognostic impact of their soluble forms (s) in patients with peripheral arterial disease (PAD). The aim of this prospective study was to verify whether plasma levels of sICAM-1 and sVCAM-1 predict cardiovascular risk in PAD, and improve the prognostic value of the ankle/brachial index (ABI) alone. Accordingly, plasma levels of sICAM-1 and sVCAM-1, and the ABI were measured in 75 PAD patients who were monitored for a mean of 24+/-13 months. Twenty-two (29.3%) patients had a cardiovascular event (15 coronary, 3 cerebrovascular and 4 peripheral events). Plasma levels of sVCAM-1 were 618+/-258 ng/mL in patients with and 496+/-164 ng/mL in those without an event (p=0.016). The corresponding sICAM-1 values were 344+/-239 ng/mL and 275+/-99 ng/mL (p=0.079). The cardiovascular event rate was higher in patients with sVCAM-1 levels above the median than in those with sVCAM-1 below the median (p=0.0027 by log rank test). Independent predictors of events were sVCAM-1 levels above the median (p=0.005) and an ABI below the median (p=0.001). Amongst patients with ABI below the median, the occurrence of sVCAM-1 above the median was associated with a 3.4-fold increase in risk (95% CI 1.308 to 9.573, p=0.013). In conclusion, increased plasma levels of sVCAM-1 have a negative prognostic impact in PAD and improve the predictive value of ABI, which is currently the most powerful risk indicator in these patients.

Functional status measured by walking impairment questionnaire and cardiovascular risk prediction in peripheral arterial disease: results of the Peripheral Arteriopathy and Cardiovascular Events (PACE) study.

The prognostic impact of the functional status of patients with intermittent claudication is still obscure. From the lists of seven general practitioners, we identified all subjects aged 40-80 years (n = 4352). Of those reporting leg symptoms while walking on the Rose questionnaire (n = 760), 60 had a qualifying diagnosis of peripheral arterial disease (PAD). All of them received the Walking Impairment Questionnaire (WIQ). For each patient affected by PAD, three sex- and age-matched controls were selected randomly. After a 24-month follow-up, survival curves showed that PAD patients with WIQ scores > median had a higher cardiovascular risk than controls, and patients with WIQ scores < median had an even poorer prognosis (p < 0.001 for all WIQ domains). In PAD, after adjustment for age, sex, ankle-brachial index and comorbidity, two WIQ domains (ie walking speed and stairclimbing) were associated with cardiovascular events. The cardiovascular risk of claudicants who had a score > median for at least three WIQ domains was intermediate versus the risk of controls and PAD patients with a WIQ score < median, also when adjusted for the covariates indicated above (RR = 3.26, p = 0.019). In intermittent claudication, a worse functional status entails a greater risk of ischemic events versus low functional impairment.

Peripheral arterial disease and cardiovascular risk in Italy. Results of the Peripheral Arteriopathy and Cardiovascular Events (PACE) study.

Objective Our knowledge about the natural history of peripheral arterial disease (PAD) is derived from studies carried out almost exclusively in northern European and northern American populations. This study was aimed at defining mortality and cardiovascular morbidity of PAD patients in Italy. Methods From the lists of seven general practitioners, we identified all subjects aged 40–80 years (n = 4352). Of those reporting leg symptoms while walking at the Rose Questionnaire (n = 760), 60 (1.6% of the general population) had PAD, as evidenced by an ankle–brachial index of < 0.90 or reduced Doppler flow velocity. For each PAD patient, three sex and age-matched controls negative to the Rose Questionnaire were randomly selected from the general practice lists. Results After 24 months of follow-up, 15% of PAD patients died, 8% from cardiovascular disease, and 25% developed a non-fatal cardiovascular event. At Cox analysis, the presence of PAD was associated with an increased risk of all-cause mortality (relative risk 4.03; 95% confidence interval 1.50–10.84; P = 0.006), cardiovascular mortality (relative risk 7.77; 95% confidence interval 1.51–40.16; P = 0.014), and non-fatal cardiovascular events (relative risk 3.11; 95% confidence interval 1.41–6.80; P = 0.005). Conclusions This Italian study shows that, in general practice, symptomatic PAD is associated with a four-fold increased risk of mortality and a nearly eight-fold increased risk of cardiovascular mortality. These figures are quite similar to those reported in northern European and northern American populations. General practitioners, who are the clinicians primarily and largely responsible for the care of these patients, should be alerted to the consequences of PAD.

Effect of Propionylcarnitine on Changes in Endothelial Function and Plasma Levels of Adhesion Molecules Induced by Acute Exercise in Patients with Intermittent Claudication

In patients with intermittent claudication, treadmill exercise may cause acute deterioration of endothelial function and increase in plasma concentrations of adhesion molecules. The authors evaluated the efficacy of intravenously administered propionylcarnitine (PLC) in preventing these phenomena. Thirty-six claudicants with postexercise decrease in brachial artery flow-mediated dilation (FMD) were randomized to either placebo or PLC (600 mg as a single bolus followed by 1 mg/kg/min for 60 minutes). In the 18 patients randomized to placebo, FMD markedly decreased with exercise before (from 6.8 ±0.4% to 4.0 ±0.4%; p<0.001) and after treatment (from 6.5 ±0.4% to 4.4 ±0.5%; p<0.001). By contrast, in the PLC group, FMD significantly decreased with exercise before treatment (from 8.0 ±0.7% to 4.4 ±0.4%; p<0.001), but not after active drug administration (from 7.1 ±0.7% to 6.0 ±0.6%; p=0.067). The difference between treatments was not significant (p=0.099; ANOVA). However, in the PLC group, the authors found that the greater the exercise-induced deterioration in endothelial function before treatment, the greater the capacity of PLC to prevent a postexercise decrease in FMD (r = -0.50, p=0.034). Accordingly, they analyzed data in the 19 patients with a baseline exercise-induced decrease in FMD ≥45% (ie, the median FMD reduction in the entire group of 36 patients), and found that the exercise-induced FMD decrease was less after PLC than after placebo (p=0.046, ANOVA). In the same subgroup, the exercise-induced increase in plasma concentrations of soluble vascular cell adhesion molecule-1 (sVCAM-1) was significantly higher before than after treatment in patients randomized to PLC (23.4 ±5% vs 15.3 ±7%, p=0.007). In conclusion, in patients with intermittent claudication suffering from a greater endothelial derangement after treadmill, PLC administration provided a protective effect against deterioration of FMD and increase of sVCAM-1 induced by exercise

Successful lower extremity angioplasty improves brachial artery flow-mediated dilation in patients with peripheral arterial disease.

INTRODUCTION Peripheral arterial disease (PAD) is associated with systemic impaired flow-mediated dilation (FMD) and increased risk for cardiovascular events. Decreased FMD may be caused by a decrease in arterial shear stress due to claudication and inflammation due to muscle ischemia and reperfusion. We assumed that endovascular revascularization of lower limb arterial obstructions ameliorates FMD and lowers inflammation through improvement of peripheral perfusion. METHODS The study was a prospective, open, randomized, controlled, single-center follow-up evaluation assessing the effect of endovascular revascularization on brachial artery reactivity (FMD) measured by ultrasound, white blood cell (WBC) count, high-sensitive C-reactive protein (hs-CRP), and fibrinogen. We investigated 33 patients (23 men) with chronic and stable PAD (Rutherford 2 to 3) due to femoropopliteal obstruction. Variables were assessed at baseline and after 4 weeks in 17 patients (group A) who underwent endovascular revascularization and best medical treatment, and in 16 patients (group B) who received best medical treatment only. RESULTS FMD did not differ between group A and B (4.96% +/- 1.86% vs 4.60% +/- 2.95%; P = .87) at baseline. It significantly improved after revascularization in group A (6.44% +/- 2.88%; P = .02) compared with group B at 4 weeks of follow-up (4.53% +/- 3.17%; P = .92), where it remained unchanged. The baseline ankle-brachial index (ABI) was similar for group A and B (0.63 +/- 0.15 vs 0.66 +/- 0.10; P = .36). At 4 weeks of follow-up, ABI was significantly increased in group A (1.05 +/- 0.15; P = .0004) but remained unchanged in group B (0.62 +/- 0.1). WBC counts of the two groups were comparable at baseline (group A: 7.6 +/- 2.26 x 10(6)/mL and group B: 7.8 +/- 2.02 x 10(6)/mL, P = .81). In group A, the leukocyte count significantly decreased after angioplasty from 7.6 +/- 2.26 to 6.89 +/- 1.35 x 10(6)/mL (P = .03). For group B, WBC count did not differ significantly compared with baseline (7.76 +/- 2.64 x 10(6)/mL; P = .94). No effects were observed on hs-CRP or fibrinogen from endovascular therapy. CONCLUSION Endovascular revascularization with reestablishment of peripheral arterial perfusion improves FMD and reduces WBC count in patients with claudication. Revascularization may therefore have clinical implications beyond relief of symptoms, for example, reducing oxidative stress caused by repeated muscle ischemia or increased shear stress due to improved ambulatory activity.