Peripheral vascular disease and hypertension: a forgotten association?

Rosuvastatin, but not atorvastatin, enhances the antihypertensive effect of cilostazol in an acute model of hypertension

PURPOSE

Hypertensive emergency, a sudden and severe increase in blood pressure, necessitates immediate intervention to avoid end-organ damage. Cilostazol, a selective phosphodiesterase-III inhibitor, has vasodilator effect. Here, we investigated the effect of two commonly used statins, atorvastatin or rosuvastatin, on cilostazol antihypertensive activity in acute model of hypertension.

METHODS

Hypertensive emergency was induced via angiotensin II intravenous infusion (120 ng.kg-1.min-1). Rats were subjected to real-time arterial hemodynamics and electrocardiogram recording while investigated drugs were injected slowly at cumulative doses 0.5, 1, and 2 mg.kg-1, individually or in combination, followed by baroreflex sensitivity (BRS) analysis and serum electrolytes (Na+ and K+) and vasomodulators (norepinephrine (NE), and nitric oxide (NO)) assessment.

RESULTS

Cilostazol reduced systolic blood pressure (SBP), while co-injection with rosuvastatin augmented cilostazol SBP-reduction up to 30 mmHg. Compared to atorvastatin, rosuvastatin boosted the cilostazol-associated reduction in peripheral resistance, as evidenced by further decrease in diastolic, pulse, and dicrotic-notch pressures. Rosuvastatin co-injection prevented cilostazol-induced changes of ejection and non-ejection durations. Additionally, rosuvastatin coadministration produced better restoration of BRS, with an observed augmented increase in BRS indexes from spectral analysis. Greater reduction in sympathetic/parasympathetic ratio and serum NE upon rosuvastatin coadministration indicates further shift in sympathovagal balance towards parasympathetic dominance. Additionally, rosuvastatin coinjection caused a greater decrease in serum sodium, while more increase in NO indicating augmented reduction of extracellular volume and endothelial dysfunction.

CONCLUSION

Rosuvastatin boosted cilostazol's antihypertensive actions through effects on peripheral resistance, BRS, sympathovagal balance, endothelial dysfunction, and electrolytes balance, while atorvastatin did not demonstrate a comparable impact.

Hypertension Related Co-Morbidities and Complications in Women of Sub-Saharan Africa: A Brief Review

Hypertension is the leading cause of cardiovascular disease in women, and sub-Saharan African (SSA) countries have some of the highest rates of hypertension in the world. Expanding knowledge of causes, management, and awareness of hypertension and its co-morbidities worldwide is an effective strategy to mitigate its harms, decrease morbidities and mortality, and improve individual quality of life. Hypertensive disorders of pregnancy (HDPs) are a particularly important subset of hypertension, as pregnancy is a major stress test of the cardiovascular system and can be the first instance in which cardiovascular disease is clinically apparent. In SSA, women experience a higher incidence of HDP compared with other African regions. However, the region has yet to adopt treatment and preventative strategies for HDP. This delay stems from insufficient awareness, lack of clinical screening for hypertension, and lack of prevention programs. In this brief literature review, we will address the long-term consequences of hypertension and HDP in women. We evaluate the effects of uncontrolled hypertension in SSA by including research on heart disease, stroke, kidney disease, peripheral arterial disease, and HDP. Limitations exist in the number of studies from SSA; therefore, we will use data from countries across the globe, comparing and contrasting approaches in similar and dissimilar populations. Our review highlights an urgent need to prioritize public health, clinical, and bench research to discover cost-effective preventative and treatment strategies that will improve the lives of women living with hypertension in SSA.

Lower extremity arterial disease perspective: IUA consensus document on "lead management". Part 1

Atherosclerotic cardiovascular disease (ASCVD) is defined as coronary heart disease (CHD), cerebrovascular disease, or lower extremity arterial disease (LEAD) also named peripheral arterial disease (PAD). ASCVD is considered to be of atherosclerotic origin and is the leading cause of morbidity and mortality mainly for individuals with diabetes mellitus (DM). In this consensus document of the International Union of Angiology the authors discuss epidemiology, risk factors, primary and secondary prophylaxis, the correlation between diabetes mellitus and LEAD, conservative and surgical treatment.

The Ability to Look Beyond: The Treatment of Peripheral Arterial Disease

This paper offers a practical overview of the contemporary management of patients with peripheral arterial disease presenting intermittent claudication (IC), including clinical and instrumental diagnosis, risk factors modification, medical management, and evidence-based revascularization indications and techniques. Decision making represents a crucial element in the management of the patient with IC; for this, we think a review of this type could be very useful, especially for non-vascular specialists.

Effects of plasma atherogenic index and plasma osmolality on arteriovenous fistula patency in hemodialysis patients

BACKGROUND

The purpose of the present study was to investigate the effects of Plasma atherogenic index (AIP) and plasma osmolality (PO) values on arteriovenous fistula (AVF) patency in patients with chronic renal failure.

METHODS

The patients with primary AVF between December 2012 and March 2020 with the diagnosis of end-stage renal disease in our clinic were included in the study. The patient data were collected retrospectively in digital medium. Diabetic patients were not included in the study. The Triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), sodium (Na), fasting blood glucose, and blood urea nitrogen (BUN) values were found and recorded from the files. AIP and PO were calculated with special formulas. Fistula patency rate in 6th, 12th, and 24th months were evaluated in 2-year follow-ups.

RESULTS

According to the results of two-year follow-ups of the 162 patients, who underwent primary AVF, 21 (13%) patients were found to have thrombosis in the 6th month, 33 (20.4%) patients in the 12th month; however,141 (87%) and 129 (79.6%) patients actively used AVF in the 6th and 12th months, respectively. The AIP and PO values that were calculated in the patient group with AVF thrombosis were significantly higher (p = 0.001, p < 0.001; respectively). In the multivariate logistic regression analysis, Na, BUN, and HDL-C variables were found to be independent predictive factors for AVF thrombosis (OR (Odds Ratio): 1.169, 95% CI (Confidence interval)): 1.056-1.294, p = 0.003; OR: 1.108, 95% CI: 1.043-1.176, p = 0.001; OR: 0.874, 95% CI: 0.820-0.932, p < 0.001; respectively). It was also found that the patency rate was 64.2% (104 patients) in the 24th month.

CONCLUSION

AIP, PO, Na, and BUN values are positively associated with AVF thrombosis. Checking AIP, Na, and BUN values will be useful in patients with end-term renal failure, who already have difficulties in renal replacement methods and vascular access.

Peripheral arterial disease and hypertension

PURPOSE OF REVIEW

Hypertension (HTN) is a well known risk factor for atherosclerosis and peripheral arterial disease (PAD). PAD affects more than 250 million people globally and is associated with worse clinical outcomes. Although multiple studies have been performed to evaluate treatment of HTN in patients with PAD, blood pressure management in this high-risk cohort remains poor.

RECENT FINDINGS

There has been conflicting evidence regarding blood pressure goals in PAD with some recent studies showing adverse outcomes with low blood pressure in this patient population. Current guidelines, however, continue to recommend treatment goals in PAD patients similar to patients without PAD. To date, no single antihypertensive drug class has shown a clear benefit in PAD population over other antihypertensive drug classes.

SUMMARY

Prospective randomized trials enrolling PAD patients are required that can shed light on optimum blood pressure target and also distinguish between different antihypertensive drugs in terms of reducing adverse outcomes.

Length of Stay, Hospital Costs and Mortality Associated With Comorbidity According to the Charlson Comorbidity Index in Immobile Patients After Ischemic Stroke in China: A National Study

BACKGROUND

In this study, we examined the length of stay (LoS)-predictive comorbidities, hospital costs-predictive comorbidities, and mortality-predictive comorbidities in immobile ischemic stroke (IS) patients; second, we used the Charlson Comorbidity Index (CCI) to assess the association between comorbidity and the LoS and hospitalization costs of stroke; third, we assessed the magnitude of excess IS mortality related to comorbidities.

METHODS

Between November 2015 and July 2017, 5114 patients hospitalized for IS in 25 general hospitals from six provinces in eastern, western, and central China were evaluated. LoS was the period from the date of admission to the date of discharge or date of death. Costs were collected from the hospital information system (HIS) after the enrolled patients were discharged or died in hospital. The HIS belongs to the hospital's financial system, which records all the expenses of the patient during the hospital stay. Cause of death was recorded in the HIS for 90 days after admission regardless of whether death occurred before or after discharge. Using the CCI, a comorbidity index was categorized as zero, one, two, and three or more CCI diseases. A generalized linear model with a gamma distribution and a log link was used to assess the association of LoS and hospital costs with the comorbidity index. Kaplan-Meier survival curves was used to examine overall survival rates.

RESULTS

We found that 55.2% of IS patients had a comorbidity. Prevalence of peripheral vascular disease (21.7%) and diabetes without end-organ damage (18.8%) were the major comorbidities. A high CCI=3+ score was an effective predictor of a high risk of longer LoS and death compared with a low CCI score; and CCI=2 score and CCI=3+ score were efficient predictors of a high risk of elevated hospital costs. Specifically, the most notable LoS-specific comorbidities, and cost-specific comorbidities was dementia, while the most notable mortality-specific comorbidities was moderate or severe renal disease.

CONCLUSION

CCI has significant predictive value for clinical outcomes in IS. Due to population aging, the CCI should be used to identify, monitor and manage chronic comorbidities among immobile IS populations.

Post-surgical wireless monitoring of arterial health progression

Early detection of limb ischemia, strokes, and heart attacks may be enabled via long-term monitoring of arterial health. Early stenosis, decreased blood flow, and clots are common after surgical vascular bypass or plaque removal from a diseased vessel and can lead to the above diseases. Continuous arterial monitoring for the early diagnosis of such complications is possible by implanting a sensor during surgery that is wirelessly monitored by patients after surgery. Here, we report the design of a wireless capacitive sensor wrapped around the artery during surgery for continuous post-operative monitoring of arterial health. The sensor responds to diverse artery sizes and extents of occlusion in vitro to at least 20 cm upstream and downstream of the sensor. It demonstrated strong capability to monitor progression of arterial occlusion in human cadaver and small animal models. This technology is promising for wireless monitoring of arterial health for pre-symptomatic disease detection and prevention.

Are hypertensive patients with history of coronary artery disease at risk for silent lower extremity artery disease?

OBJECTIVES

We aimed to investigate the association between hypertension and asymptomatic lower extremity artery disease (LEAD) in outpatients with known history of coronary artery disease (CAD).

METHODS

Patients with known history of CAD who have been undergone coronary angiography and have significant coronary artery stenosis (more than 60%) were included. LEAD was defined as ankle-brachial index (ABI) < 0.9 in either leg. The risk of LEAD in hypertensive group was analyzed using chi-square test, and correlation between blood pressure (BP) and ABI was analyzed using Pearson correlation test in SPSS v.25.

RESULTS

One hundred and four patients were included. 82.7% of patients were male. Mean age was 57.05 ± 7.97. The prevalence of hypertension was 35.6%, and the prevalence of LEAD was 16.3%. A higher proportion of LEAD was found in hypertensive (18.9%) compared to non-hypertensive (14.9%), although not statistically significant (OR: 1.33; 95% CI: 0.46 to 3.85; p=0.598). There was an association between ABI and systolic BP (p=0.016), but not with diastolic BP (p=0.102).

CONCLUSIONS

Our study showed that the prevalence of LEAD in hypertension, especially in the CAD population, is relatively high. There was no association between hypertension and LEAD, but a higher prevalence of LEAD was found in hypertensive patients. Nevertheless, LEAD screening is still recommended in hypertensive patients, especially in the CAD population, given the fact that outcomes of health and mortality are worse for those with concomitants of these diseases.

Medical Management of Peripheral Arterial Disease: Deciphering the Intricacies of Therapeutic Options

Due to the pathophysiology of atherosclerosis, the management for coronary artery disease and peripheral arterial disease (PAD) were considered homogenous, with therapies focused on the use of lipid-lowering medications, antiplatelet therapy, glucose control, and blood pressure management. However, more recently, studies have supported the use of tailored therapeutics and medical targets for patients with PAD that sometimes differ from those for coronary artery disease. Moreover, we are now witnessing large randomized PAD-specific trials that have altered therapeutic regimens and targets. Given these updates, dissemination of knowledge is lacking, as evidenced by discordant guideline recommendations. This comprehensive review provides an overview of contemporary therapeutic options for secondary prevention for patients with PAD.

Peripheral artery disease risk factors in Jeddah, Saudi Arabia: a retrospective study

Background

Peripheral artery disease (PAD) is a major health problem in Saudi Arabia with considerable implications for morbidity and mortality. Many risk factors have been established for developing PAD, but the prevalence of these risk factors is variable from one country to another.

Aim

To identify the risk factors for PAD and study their prevalence in Jeddah, Saudi Arabia.

Methods

A retrospective chart review study was conducted in a tertiary center in Jeddah from July 2012 to September 2015. All patients with PAD were recruited into this study, and their data were analyzed using IBM SPSS. Correlation between PAD and various risk factors was studied using Spearman's coefficient.

Results

A total of 261 patients were recruited, of which 55% were males. Hypertension, diabetes type 2, and obesity were found among 34.2%, 33.3%, and 29.2% of the patients, respectively. About 45% had a history of previous vascular surgery, and amputation was performed in 6.9% particularly in legs. Hypertension and metabolic syndrome were the only risk factors that showed a significant correlation with PAD (P=0.039 and 0.040, respectively).

Conclusion

The most prevalent risk factors for PAD in Jeddah were hypertension, diabetes, obesity, and smoking. Hypertension and metabolic syndrome were the only risk factors significantly associated with PAD. Males were often more affected by PAD than females. The most commonly affected site was the lower limbs.

An Inductive Sensing System to Measure In-Socket Residual Limb Displacements for People Using Lower-Limb Prostheses

The objective of this research was to assess the performance of an embedded sensing system designed to measure the distance between a prosthetic socket wall and residual limb. Low-profile inductive sensors were laminated into prosthetic sockets and flexible ferromagnetic targets were created from elastomeric liners with embedded iron particles for four participants with transtibial amputation. Using insights from sensor performance testing, a novel calibration procedure was developed to quickly and accurately calibrate the multiple embedded sensors. The sensing system was evaluated through laboratory tests in which participants wore sock combinations with three distinct thicknesses and conducted a series of activities including standing, walking, and sitting. When a thicker sock was worn, the limb typically moved further away from the socket and peak-to-peak displacements decreased. However, sensors did not measure equivalent distances or displacements for a given sock combination, which provided information regarding the fit of the socket and how a sock change intervention influenced socket fit. Monitoring of limb⁻socket displacements may serve as a valuable tool for researchers and clinicians to quantitatively assess socket fit.

A study paradigm integrating prospective epidemiologic cohorts and electronic health records to identify disease biomarkers

Defining the full spectrum of human disease associated with a biomarker is necessary to advance the biomarker into clinical practice. We hypothesize that associating biomarker measurements with electronic health record (EHR) populations based on shared genetic architectures would establish the clinical epidemiology of the biomarker. We use Bayesian sparse linear mixed modeling to calculate SNP weightings for 53 biomarkers from the Atherosclerosis Risk in Communities study. We use the SNP weightings to computed predicted biomarker values in an EHR population and test associations with 1139 diagnoses. Here we report 116 associations meeting a Bonferroni level of significance. A false discovery rate (FDR)-based significance threshold reveals more known and undescribed associations across a broad range of biomarkers, including biometric measures, plasma proteins and metabolites, functional assays, and behaviors. We confirm an inverse association between LDL-cholesterol level and septicemia risk in an independent epidemiological cohort. This approach efficiently discovers biomarker-disease associations.

Biomarker identification requires prohibitively large cohorts with gene expression and phenotype data. The approach introduced here learns polygenic predictors of expression from genetic and expression data, used to infer biomarker levels in patients with genetic and disease information.

American Heart Association High Blood Pressure Protocol 2017: A Literature Review

Hypertension is the most prevalent clinical symptom arising from various cardiovascular disorders. Likewise, it is considered a precursor or sequelae to the development of acute coronary artery disease and congestive heath failure (CHF). Hypertension has been considered a cardinal criterion to determine cardiovascular function. According to the World Health Organization (WHO) global observatory data, hypertension causes more than 7.5 million deaths a year, about 12.8% of the total human mortality. Similarly, the Center for Disease Control (CDC) states that 35% of the American adults have been estimated to have a persistently high blood pressure, which makes it about one in every three adults. Hypertension is a modifiable symptom that can be managed through pharmacological and non-pharmacological methods and standard protocols set forth by the American Heart Association (AHA). With new findings from various clinical trials related to the management of hypertension, new developments and recommendations have been made to update the previously established protocols for hypertension. This article aims to discuss and dissect the modern updates of hypertension management as comprehensively elaborated in the 2017 Hypertension Clinical Practice Guidelines.

Relationship between walking capacity and ambulatory blood pressure in patients with intermittent claudication

OBJECTIVE

Patients with intermittent claudication (IC) often have high blood pressure (BP), which increases their cardiovascular risk. However, whether walking capacity is associated with BP levels in patients with IC remains unknown. Therefore, this study was designed to investigate whether the total walking distance is associated with ambulatory BP in patients with IC.

PARTICIPANTS AND METHODS

This was a cross-sectional study of 75 patients with IC (58 men; 17 women). A maximal treadmill test (Gardner protocol) was performed to assess total walking distance in these patients. Furthermore, ambulatory BP, heart rate, rate-pressure product, and BP load were obtained over a 24-h period. One-way analysis of variance and multiple linear regression were carried out.

RESULTS

Walking capacity was correlated negatively with the following: (i) asleep systolic BP, diastolic BP, mean BP and heart rate; (ii) 24-h, awake and asleep RPP; and (iii) awake and asleep systolic BP load (all P<0.05). These associations occurred irrespective of confounders such as age, sex, BMI, smoking status, and number of antihypertensive medications.

CONCLUSION

A better walking capacity is associated with lower ambulatory BP parameters in patients with IC.

Using Predicted Cardiovascular Disease Risk in Conjunction With Blood Pressure to Guide Antihypertensive Medication Treatment

Using cardiovascular disease (CVD) risk instead of or in addition to blood pressure (BP) to guide antihypertensive treatment is an active area of research. The purpose of this review is to provide an overview of studies that could inform this treatment paradigm. We review data from randomized trials on relative and absolute CVD risk reduction that can occur when antihypertensive treatment is guided by CVD risk. We also review population-level data on using CVD risk in conjunction with BP to guide antihypertensive treatment, the broad distribution in CVD risk for people with similar BP levels, and the use of CVD risk for guiding antihypertensive treatment among subgroups including older adults, young adults, and those with diabetes mellitus or chronic kidney disease. In addition, we review potential challenges in implementing antihypertensive treatment recommendations that incorporate CVD risk. In closing, we provide recommendations for using CVD risk in combination with BP to guide antihypertensive treatment.

Knowledge of peripheral arterial disease: Results of an intervention to measure and improve PAD knowledge in Toronto

Background

Prevalence of peripheral arterial disease (PAD) has dramatically increased in both developing, as well as developed countries. However, significant knowledge and practice gaps persist. In Canada, efforts to improve this knowledge level are lacking. In this study, we examine PAD knowledge in Toronto, and evaluate a pilot intervention to address the knowledge gaps.

Objectives

Measure PAD awareness in Toronto, and evaluate an intervention to improve PAD knowledge among the public.

Methods

In the context of a community-based awareness campaign, an interview-based survey was used to assess the PAD awareness among general public. A sample of participants was split into two arms: control (survey only) and intervention (survey and education pamphlet), the choice between assigning the site as case or control was random. A follow-up telephone and email-based survey was conducted after 6 weeks to assess the attained knowledge level of PAD.

Results

Two hundred thirty-seven participants completed the baseline survey. One hundred eighty-eight participants (78.7%) had never heard of PAD. The remaining “PAD-aware” cohort had low overall knowledge of the disease characteristics. Participants from each arm completed the follow-up survey. The level of education, age, and gender were not predictors of knowledge scores; however, age was a predictor of PAD awareness, while gender and level of education were not. Participants in the intervention group showed significant knowledge scores improvement in five PAD domains, while those from control group showed significant improvement in their preventative measures, treatment modalities, and total scores. The impact of the study intervention on average scores was borderline not significant ( p = 0.05).

Conclusion

PAD knowledge gap in the Canadian public is larger than what was previously reported. Educational campaigns are necessary to address this gap and improve the outcome of PAD patients through patients' activation. Our results are encouraging and warrant a next intervention to explore an educational program impact on PAD knowledge.

Do the Effects of Secondary Prevention of Cardiovascular Events in PAD Patients Differ from Other Atherosclerotic Disease?

Atherosclerosis is considered a generalized disease. Similar or identical etiopathogenetic mechanisms and risk factors are involved in various atherosclerotic diseases, and the positive effects of preventive measures on atherogenesis in different parts of the arterial system were shown. However, until know, great emphasis has been placed on the aggressive pharmacological management of coronary artery disease (CHD), while less attention has been devoted to the management of peripheral arterial disease (PAD), despite its significant morbidity and mortality. Data on the efficacy of preventive measures in PAD patients have mostly been gained from subgroup analyses from studies devoted primarily to the management of coronary patients. These data have shown that treatment of risk factors for atherosclerosis with drugs can reduce cardiovascular events also in patients with PAD. The effects of some preventive procedures in PAD patients differ from coronary patients. Aspirin as a basic antiplatelet drug has been shown to be less effective in PAD patients than in coronary patients. The latest Antithrombotic Trialists' Collaboration (ATC) meta-analysis demonstrates no benefit of aspirin in reducing cardiovascular events in PAD. Statins reduce cardiovascular events in all three of the most frequently presented cardiovascular diseases, including PAD to a comparable extent. Recent studies indicate that in PAD patients, in addition to a reduction in cardiovascular events, statins may have some hemodynamic effects. They prolong walking distance and improve quality of life. Similarly, angiotensin enzyme inhibitors are also effective in the prevention of cardiovascular events in coronary, cerebrovascular, as well as PAD patients and show positive effects on the walking capacity of patients with intermittent claudication. In PAD patients, the treatment of hypertension and diabetes also effectively prevents cardiovascular morbidity and mortality. As PAD patients are at a highest risk of cardiovascular complications, the risk factors of atherosclerosis should be treated intensively in this group of patients. Most of the preventive measures, including the drugs used for prevention of CHD, are also effective in PAD patients.

Treatment of hypertension in peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) causes considerable morbidity and mortality. Hypertension is a risk factor for PAD. Treatment for hypertension must be compatible with the symptoms of PAD. Controversy regarding the effects of beta-adrenoreceptor blockade for hypertension in patients with PAD has led many physicians to stop prescribing beta-adrenoreceptor blockers. Little is known about the effects of other classes of anti-hypertensive drugs in the presence of PAD. This is the second update of a Cochrane review first published in 2003.

OBJECTIVES

To determine the effects of anti-hypertensive drugs in patients with both raised blood pressure and symptomatic PAD in terms of the rate of cardiovascular events and death, symptoms of claudication and critical leg ischaemia, and progression of atherosclerotic PAD as measured by ankle brachial index (ABI) changes and the need for revascularisation (reconstructive surgery or angioplasty) or amputation.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Cochrane Peripheral Vascular Diseases Group Specialised Register (last searched March 2013) and CENTRAL (2013, Issue 2).

SELECTION CRITERIA

Randomised controlled trials (RCTs) of at least one anti-hypertensive treatment against placebo or two anti-hypertensive medications against each other, with interventions lasting at least one month. Trials had to include patients with symptomatic PAD.

DATA COLLECTION AND ANALYSIS

Data were extracted by one author (DAL) and checked by the other (GYHL). Potentially eligible studies were excluded when the results presentation prevented adequate extraction of data and enquiries to authors did not yield raw data.

MAIN RESULTS

Eight RCTs were included with a total of 3610 PAD patients. Four studies compared a recognised class of anti-hypertensive treatment with placebo and four studies compared two anti-hypertensive treatments with each other. Studies were not pooled due to the variation of the comparisons and the outcomes presented. Overall the quality of the available evidence was unclear, primarily as a result of a lack of detail in the study reports on the randomisation and blinding procedures and incomplete outcome data. Two studies compared angiotensin converting enzyme (ACE) inhibitors against placebo. In one study there was a significant reduction in the number of cardiovascular events in patients receiving ramipril (odds ratio (OR) 0.72, 95% confidence interval (CI) 0.58 to 0.91; n = 1725). In the second trial using perindopril (n = 52) there was a marginal increase in claudication distance but no change in ABI and a reduction in maximum walking distance. A trial comparing the calcium antagonist verapamil versus placebo in patients undergoing angioplasty (n = 96) suggested that verapamil reduced restenosis (per cent diameter stenosis (± SD) 48.0% ± 11.5 versus 69.6% ± 12.2; P < 0.01), although this was not reflected in the maintenance of a high ABI (0.76 ± 0.10 versus 0.72 ± 0.08 for verapamil versus placebo). Another study (n = 80) demonstrated no significant difference in arterial intima-media thickness (IMT) in men receiving the thiazide diuretic hydrochlorothiazide (HCTZ) compared to those receiving the alpha-adrenoreceptor blocker doxazosin (-0.12 ± 0.14 mm and -0.08 ± 0.13 mm, respectively; P = 0.66). A study (n = 36) comparing telmisartan to placebo found a significant improvement in maximum walking distance at 12 months with telmisartan (median (interquartile range (IQR)) 191 m (157 to 226) versus 103 m (76 to 164); P < 0.001) but no differences in ABI (median (IQR) 0.60 (0.60 to 0.77) versus 0.52 (0.48 to 0.67)) or arterial IMT (median (IQR) 0.08 cm (0.07 to 0.09) versus 0.09 cm (0.08 to 0.10)). Two studies compared the beta-adrenoreceptor blocker nebivolol with either the thiazide diuretic HCTZ or with metoprolol. Both studies found no significant differences in intermittent or absolute claudication distance, ABI, or all-cause mortality between the anti-hypertensives. A subgroup analysis of PAD patients (n = 2699) in a study which compared a calcium antagonist-based strategy (verapamil slow release (SR) ± trandolapril) to a beta-adrenoreceptor blocker-based strategy (atenolol ± hydrochlorothiazide) found no significant differences in the composite endpoints of death, non-fatal myocardial infarction or non-fatal stroke with or without revascularisation (OR 0.90, 95% CI 0.76 to 1.07 and OR 0.96, 95% CI 0.82 to 1.13, respectively).

AUTHORS' CONCLUSIONS

Evidence on the use of various anti-hypertensive drugs in people with PAD is poor so that it is unknown whether significant benefits or risks accrue. However, lack of data specifically examining outcomes in PAD patients should not detract from the overwhelming evidence on the benefit of treating hypertension and lowering blood pressure.

Hypotensive activity of auraptene, a monoterpene coumarin from Citrus spp

CONTEXT

Citrus spp. (Rutaceae) are well-documented for their cardioprotective properties. Auraptene is a bioactive monoterpene coumarin ether abundantly present in the Citrus spp.

OBJECTIVE

To investigate the hypotensive activity of auraptene.

METHODS

Different groups of normotensive rats (n = 5 in each group) were subjected to single intravenous injections of auraptene (125, 250 and 500 µg/kg), nifedipine (as positive control; 63, 125 and 250 µg/kg) or negative control [DMSO/normal saline (1:3)]. Mean arterial blood pressure (MABP) and heart rate (HR) were evaluated following each treatment.

RESULTS

A dose-dependent hypotensive effect was observed following auraptene injection, which was significant at 250 and 500 µg/kg (p < 0.001) but not 125 µg/kg (p > 0.05). With respect to the positive control, nifedipine reduced MABP at all tested doses, dose-dependently and significantly (p < 0.001). The MABP lowering effect of auraptene was found to be significantly lower than that of nifedipine (p < 0.001).

CONCLUSION

In light of the present findings, auraptene has moderate hypotensive activity. Further investigations are recommended to explore the effects of higher doses as well as oral administration of this phytochemical.

Quantitative CMR markers of impaired vascular reactivity associated with age and peripheral artery disease

BACKGROUND

The aim of this study was to develop and evaluate an integrated CMR method incorporating dynamic oximetry, blood flow and pulse-wave velocimetry to assess vascular reactivity in patients with peripheral artery disease (PAD) and healthy controls.

METHODS AND RESULTS

The study population consisted of young healthy subjects (YH, 30 ± 7 yrs, N = 19),PAD (71 ± 9 yrs, N = 38), and older healthy controls (OHC, 68 ± 9 yrs, N = 43). Peripheral vascular reactivity was evaluated with two methods, time-resolved quantification of blood flow velocity and oxygenation level in the femoral artery and vein, respectively, performed simultaneously both at rest and hyperemia. Aortic stiffness was assessed via pulse-wave velocity. Oximetric data showed that compared to OHC, the time-course of the hemoglobin oxygen saturation in PAD patients had longer washout time (28.6 ± 1.2 vs 16.9 ± 1.1 s, p < 0.0001), reduced upslope (0.60 ± 0.1 vs 1.3 ± 0.08 HbO2/sec, p < 0.0001) and lower overshoot (8 ± 1.4 vs 14 ± 1.2 HbO2, p = 0.0064). PAD patients also had longer-lasting antegrade femoral artery flow during hyperemia (51 ± 2.1 vs 24 ± 1.8 s, p < 0.0001), and reduced peak-to-baseline flow rate (3.1 ± 0.5 vs 7.4 ± 0.4, p < 0.0001). Further, the pulsatility at rest was reduced (0.75 ± 0.32 vs 5.2 ± 0.3, p < 0.0001), and aortic PWV was elevated (10.2 ± 0.4 vs 8.1 ± 0.4 m/s, p = 0.0048).

CONCLUSION

The proposed CMR protocol quantifies multiple aspects of vascular reactivity and represents an initial step toward development of a potential tool for evaluating interventions, extrapolating clinical outcomes and predicting functional endpoints based on quantitative parameters.

Peripheral arterial disease in the Middle East: Underestimated predictor of worse outcome

Peripheral arterial disease (PAD) is a common manifestation of systemic atherosclerosis and is associated with significant morbidity and mortality. The prevalence of PAD in the developed world is approximately 12% among adult population, which is age-dependent and with men being affected slightly more than women. Despite the strikingly high prevalence of PAD, the disease is underdiagnosed. Surprisingly, more than 70% of primary health care providers in the US were unaware of the presence of PAD in their patients. The clinical presentation of PAD may vary from asymptomatic to intermittent claudication, atypical leg pain, rest pain, ischemic ulcers, or gangrene. Claudication is the typical symptomatic expression of PAD. However, the disease may remains asymptomatic in up to 50% of all PAD patients. PAD has also been reported as a marker of poor outcome among patients with coronary artery disease. Despite the fact that the prevalence of atherosclerotic disease is increasing in the Middle East with increasing cardiovascular risk factors (tobacco use, diabetes mellitus and the metabolic syndrome), data regarding PAD incidence in the Middle East are scarce.

Disruption of Na+,HCO₃⁻ cotransporter NBCn1 (slc4a7) inhibits NO-mediated vasorelaxation, smooth muscle Ca²⁺ sensitivity, and hypertension development in mice

BACKGROUND

Disturbances in pH affect artery function, but the mechanistic background remains controversial. We investigated whether Na(+), HCO₃- transporter NBCn1, by regulating intracellular pH(pH₁), influences artery function and blood pressure regulation.

METHODS AND RESULTS

Knockout of NBCn1 in mice eliminated Na+, HCO₃⁻ cotransport and caused a lower steady-state pH(i) in mesenteric artery smooth muscle and endothelial cells in situ evaluated by fluorescence microscopy. Using myography, arteries from NBCn1 knockout mice showed reduced acetylcholine-induced NO-mediated relaxations and lower rho-kinase-dependent norepinephrine-stimulated smooth muscle Ca²⁺ sensitivity. Acetylcholine-stimulated NO levels (electrode measurements) and N-nitro-l-arginine methyl ester-sensitive l-arginine conversion (radioisotope measurements) were reduced in arteries from NBCn1 knockout mice, whereas relaxation to NO-donor S-nitroso-N-acetylpenicillamine, acetylcholine-induced endothelial Ca²⁺ responses (fluorescence microscopy), and total and Ser-1177 phosphorylated endothelial NO-synthase expression (Western blot analyses) were unaffected. Reduced NO-mediated relaxations in arteries from NBCn1 knockout mice were not rescued by superoxide scavenging. Phosphorylation of myosin phosphatase targeting subunit at Thr-850 was reduced in arteries from NBCn1 knockout mice. Evaluated by an in vitro assay, rho-kinase activity was reduced at low pH. Without CO₂/HCO₃⁻, no differences in pH(i), contraction or relaxation were observed between arteries from NBCn1 knockout and wild-type mice. Based on radiotelemetry and tail-cuff measurements, NBCn1 knockout mice were mildly hypertensive at rest, displayed attenuated blood pressure responses to NO-synthase and rho-kinase inhibition and were resistant to developing hypertension during angiotensin-II infusion.

CONCLUSIONS

Intracellular acidification of smooth muscle and endothelial cells after knockout of NBCn1 inhibits NO-mediated and rho-kinase-dependent signaling in isolated arteries and perturbs blood pressure regulation.

The contribution of cardiovascular risk factors to peripheral arterial disease in South Asians and Blacks: a sub-study to the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study

OBJECTIVE

To determine whether differences exist in prevalence of peripheral arterial disease (PAD) between South Asians (people originating from India, Pakistan and Bangladesh) and Blacks (Black Caribbean and Black African), the two largest minority ethnic groups in the UK. To determine if associations with cardiovascular risk factors and this disease differ between these two ethnic groups.

PATIENTS AND METHODS

We recruited 572 patients (356 South Asian and 216 Blacks) > or = 45 years as a sub-study to a community screening project, the Ethnic-Echocardiographic Heart of England Screening (E-ECHOES) study. All subjects completed an interviewer-led questionnaire, anthropometric measurements and blood sampling. Ankle brachial pressure index (ABPI) was calculated and intermittent claudication was assessed using the Edinburgh Claudication Questionnaire. The presence of PAD was defined as ABPI <0.9.

RESULTS

The mean age was 62 years overall with no difference between the two ethnic groups. The prevalence of PAD was 13.2% [95% confidence interval (CI) 9.7-16.7] in South Asians and 10.2% (95% CI 6.2-14.2) in Blacks with no significant difference between the two ethnic groups. The prevalence of PAD was higher in South Asian women than Black women (16.3 vs. 6.1%; P = 0.011). No difference in prevalence was found in men (11 vs. 14% P = 0.47, in South Asians and Blacks, respectively). The prevalence of intermittent claudication was 0.9% (95% CI 0.11-1.63). On multivariate logistic regression, mean systolic blood pressure, diabetes, smoking and male sex were independently associated with PAD in South Asians (P = 0.016, 0.022, 0.037 and 0.008, respectively). In Blacks, only age remained independently associated with PAD on multivariate logistic regression (P = 0.003).

CONCLUSION

The prevalence of PAD is similar in South Asians and Blacks, and similar to levels reported in pre-dominantly White populations. South Asian women had a higher prevalence of PAD than Black women, which is not explained by traditional cardiovascular risk factors.

Treatment of hypertension in peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) causes considerable morbidity and mortality. Hypertension is a risk factor for PAD. Treatment for hypertension must be compatible with the symptoms of PAD. Controversy regarding the effects of beta-blockade for hypertension in patients with PAD has led many physicians to stop prescribing beta-blockers. Little is known about the effects of other classes of anti-hypertensive drugs in the presence of PAD. This is an update of a Cochrane review first published in 2003.

OBJECTIVES

To determine the effects of anti-hypertensive drugs on cardiovascular events and death, symptoms of claudication, critical leg ischaemia, progression of PAD and revascularisation or amputation in people with hypertension and PAD SEARCH STRATEGY: The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched May 2009) and the Cochrane Central Register of Controlled Trials (The Cochrane Library 2009, Issue 2). The authors studied abstracts of cardiology meetings.

SELECTION CRITERIA

Randomised controlled trials of at least one anti-hypertensive treatment against placebo, or two anti-hypertensive medications against each other, with interventions lasting at least one month. Trials had to include patients with symptomatic PAD.

DATA COLLECTION AND ANALYSIS

Data were extracted by one author (DAL) and checked by the other (GYHL). Eligible studies were excluded when results presentation prevented adequate extraction of data and enquiries to authors did not yield raw data.

MAIN RESULTS

Four studies were included. Two compared ACE inhibitors against placebo. In the HOPE study there was a significant reduction in the number of cardiovascular events in 168 patients receiving ramipril (OR 0.72, 95% confidence interval 0.58 to 0.91). In the second trial using perindopril in a small numbers of patients, there was a marginal increase in claudication distance but no change in ankle brachial pressure index (ABPI) and a reduction in maximum walking distance.The third trial in patients undergoing angioplasty suggested that the calcium antagonist verapamil reduced restenosis, although this was not reflected in the maintenance of a high ABPI. Another small study demonstrated no significant difference in arterial intima-media thickness with men receiving the thiazide diuretic hydrochlorathiazide compared to those receiving the alpha-adrenoreceptor blocker doxazosin.

AUTHORS' CONCLUSIONS

Evidence on various anti-hypertensive drugs in people with PAD is poor so that it is unknown whether significant benefits or risks accrue from their use. Lack of data specifically examining outcomes in PAD patients should not detract from the compelling evidence of the benefit of treating hypertension and lowering blood pressure.

Ethnicity and peripheral artery disease

Peripheral arterial disease (PAD) is an important healthcare problem and is an indicator of widespread atherosclerosis in other vascular territories, such as the cerebral and coronary circulations. PAD is associated with considerable morbidity and mortality. Most population-based studies investigating PAD prevalence and risk factors for its development and progression have been based on predominantly White ethnic groups. Much less is known about the characteristics of this disease in other ethnic groups. Understanding the epidemiology of PAD amongst ethnic minority groups is relevant, given that the population of minority ethnic groups in countries such as the United Kingdom rose by 53% between 1991 and 2001 and is expected to rise further in the future. This article aims to provide an overview of possible pathophysiological differences between ethnic groups for PAD, focussing predominantly on South Asians (people originating from India, Bangladesh and Pakistan) and Blacks (people of Black Caribbean and Black African descent) as these groups comprise the majority of all ethnic minorities in the United Kingdom.

Relationship between serum bilirubin and carotid atherosclerosis in hypertensive patients

OBJECTIVE

To investigate the relationship between serum bilirubin and carotid atherosclerosis in patients with hypertension.

PATIENTS AND METHODS

Carotid artery ultrasonography was performed in 198 patients (104 males, average age of 65.6+/-7.1 years) with hypertension. Serum levels of bilirubin and C-reactive proteins (CRP) were measured at the same time.

RESULTS

Carotid atherosclerosis was detected in 133 patients, 87 of them had carotid artery plaque. The prevalence of stroke (20.3%) and myocardial infarction (13.5%) in the atherosclerosis group was higher than in the non-atherosclerosis group (9.2% and 6.2%, respectively, p<0.05). The average total serum bilirubin in the atherosclerosis group was lower than in the non-atherosclerosis group (12.8+/-1.3 vs 16.8+/-1.5 micromol/L, p<0.01), whereas the average serum of CRP was higher (4.1+/-1.1 vs 2.3+/-0.7 mg/L, p<0.01). After adjusting other factors such as age, total cholesterol, diabetes and systolic blood pressure, total serum bilirubin was negatively associated with carotid atherosclerosis in women and men, with odds ratios of 0.49 (95% CI, 0.28 to 0.71; p<0.01) and 0.66 (95% CI, 0.46 to 0.80; p<0.01). Serum CRP was positively correlated to carotid atherosclerosis, with odds ratios of 1.76 (95% CI, 1.36 to 2.04; p<0.01) in women and 1.95 (95% CI, 1.46 to 2.82; p<0.01) in men.

CONCLUSION

Carotid atherosclerosis was associated with a high prevalence of stroke or myocardial infarction in hypertensive patients. Serum bilirubin was negatively associated with carotid atherosclerosis.

Prevalence of Metabolic Syndrome in Patients With Clinically Advanced Peripheral Vascular Disease

The aim of this cross-sectional study was to determine the prevalence of metabolic syndrome (MetS) and its components among 100 patients with progressive peripheral arterial disease (PAD) referred for diagnostic angiography in preparation for a revascularization procedure. The prevalence of MetS was more than 95%. Diabetes mellitus was the most prevalent component followed by hypertension and low high-density lipoprotein. Almost half the patients aggregated in the highest metabolic score category. A direct relationship was identified between the number of MetS components and serum uric acid ( P = .001) and C-reactive protein ( P = .826), whereas an inverse relationship was seen between the clustering of components and androgen levels in men ( P < .001). For PAD, which could have a benign clinical course, early screening for MetS might identify those at greater risk of failing conservative therapy and progressing to a more aggressive atherosclerotic disease typically associated with high morbidity and mortality.

Cutaneous sensibility and peripheral nerve function in patients with unmedicated essential hypertension

Sensorimotor deficits in patients with essential hypertension may be due to impaired nerve function. Cutaneous sensory thresholds, median nerve sensory and motor conduction velocities, and median nerve sensory action potential amplitudes were assessed in 30 patients with unmedicated essential hypertension and 29 normotensives. Cutaneous sensory thresholds were higher and sensory action potential amplitudes smaller in hypertensives than normotensives whereas sensory and motor nerve conduction velocities did not differ between groups. These data suggest that hypertension may reduce the number of active sensory nerve fibers without affecting myelination. Sensory action potential amplitudes were inversely related to cutaneous sensory thresholds, suggesting that subclinical axonal neuropathy of sensory afferents may help account for perceptual deficits that characterize hypertension.

Mouse models for atherosclerosis and pharmaceutical modifiers

Atherosclerosis is a multifactorial highly-complex disease with numerous etiologies that work synergistically to promote lesion development. The ability to develop preventive and ameliorative treatments will depend on animal models that mimic the human subject metabolically and pathophysiologically and will develop lesions comparable to those in humans. The mouse is the most useful, economic, and valid model for studying atherosclerosis and exploring effective therapeutic approaches. Among the most widely used mouse models for atherosclerosis are apolipoprotein E-deficient (ApoE-/-) and LDL receptor-deficient (LDLr-/-) mice. An up-and-coming model is the ApoE*3Leiden (E3L) transgenic mouse. Here, we review studies that have explored how and to what extent these mice respond to compounds directed at treatment of the risk factors hypercholesterolemia, hypertriglyceridemia, hypertension, and inflammation. An important outcome of this survey is that the different models used may differ markedly from one another in their response to a specific experimental manipulation. The choice of a model is therefore of critical importance and should take into account the risk factor to be studied and the working spectrum of the compounds tested.

Pharmacological prevention of atherothrombotic events in patients with peripheral arterial disease

Peripheral arterial disease (PAD) is strongly associated with atherosclerosis in the coronary and carotid arteries, leading to a highly increased incidence of myocardial infarction, ischaemic stroke and cardiovascular death. Fortunately, pharmacological interventions in large clinical trials have been as effective in subgroups of patients with PAD as in subjects with other atherosclerotic disease. Antiplatelet treatment is indicated in virtually all patients with PAD. Aspirin 75-325 mg day(-1) is considered as first-line treatment, and clopidogrel 75 mg day(-1) is an effective alternative. Statin therapy is indicated to achieve a target low-density lipoprotein cholesterol level of < or = 2.5 mmol L(-1) in patients with PAD and there is emerging evidence that even lower levels are beneficial. Lowering of plasma homocysteine by supplementing folic acid, vitamin B(12) and vitamin B(6) is not recommended in patients with mild to moderate hyperhomocysteinaemia in the 12-25 micromol L(-1) range, since it does not reduce the incidence of cardiovascular events. Antihypertensive treatment is indicated to achieve a goal blood pressure of < or = 140/90 mmHg or < or = 130/80 mmHg in the presence of diabetes or chronic kidney disease. All classes of antihypertensive drugs are acceptable for treatment of hypertension in patients with PAD, but angiotensin-converting enzyme inhibitors ramipril or perindopril are especially appropriate because they reduce the incidence of cardiovascular events beyond their blood pressure-lowering effects. Beta-blockers should not be used as first-line antihypertensive treatment. Diabetic patients with PAD should reduce their glycosylated haemoglobin to < or = 7%. In conclusion, pharmacological secondary prevention of cardiovascular morbidity and mortality in patients with PAD should be as comprehensive as that in patients with established coronary or cerebrovascular disease.

Management of risk in peripheral artery disease: recent therapeutic advances

Peripheral artery disease (PAD) is a problem frequently encountered by physicians who care for patients with coronary heart disease, diabetes mellitus, renal insufficiency, congestive heart failure, or stroke. Patients with PAD are at heightened risk of myocardial infarction and stroke and are 6 times more likely to die of cardiovascular causes than persons without the disease. There is an urgent need for therapies that reduce the incidence of vascular complications among patients with PAD. In recent years, a number of risk-lowering therapies have been validated by randomized controlled trials enrolling large numbers of patients with PAD. The available evidence supports aggressive lifestyle modification as well as the provision of an antiplatelet agent, an HMGCoA (3-hydroxy-3-methylglutaryl coenzyme A) reductase inhibitor, and an angiotensin-converting enzyme inhibitor for cardiovascular protection in patients with PAD. As a result of their high baseline risk and the proven effectiveness of these interventions, most patients with PAD will benefit substantially from aggressive medical therapy.

Measurement of critical lower limb tissue hypoxia by coupling chemical and optical techniques

It has been a long-term goal to develop non-invasive methods that can detect critical levels of tissue hypoxia to help in the management of chronic lower limb ischaemia. In the present study, skeletal muscle oxygenation was measured using a new Clark-type TCPO2 [transcutaneous PO2 (partial pressure of O2)]/PCO2 (partial pressure of CO2) monitoring system and optical NIRS (near-infrared spectroscopy) at graded levels of hypoxaemia using a rabbit model (n=6). The TCPO2/PCO2 probe was placed on the shaved hindlimb to record SPO2 (skin PO2) and SPCO2 (skin PCO2) continuously. A pair of NIRS probes were placed on the limb to monitor HbO2 (oxyhaemoglobin) and Hb (deoxyhaemoglobin). Graded hypoxaemia was achieved by stepwise reductions of FiO2 (fraction of inspired O2) from 30% to 6%. Animals were allowed to recover after each episode of hypoxia at an FiO2 of 30% as indicated by normalized arterial blood PO2. There was a significant (P<0.05) decrease in SPO2 with all grades of hypoxaemia and no significant changes in SPCO2. There was a significant (P<0.05) increase in muscle Hb with all grades of hypoxaemia and a significant (P<0.05) decrease in HbO2 when FiO2 was below 15%. A significant correlation was found between the SPO2 and HbO2 (r=0.92, P<0.001) and both were significantly correlated with arterial blood PO2 (P<0.001). The new TCPO2/PCO2 system, in addition to its application for the assessment of conditions such as chronic venous insufficiency where alteration in skin oxygenation occurs solely, also has potential in conditions such as peripheral vascular disease where both skin and muscle oxygenation may be affected.

Thrombogenesis and endothelial damage/dysfunction in peripheral artery disease. Relationship to ethnicity and disease severity

Peripheral artery disease (PAD) and intermittent claudication are common in men aged over 55 years. Once the diagnosis has been made, very few patients suffer from a deterioration of the disease. Those that do deteriorate tend to do so due to thrombosis of an affected artery. It is apparent that the disruption in the vessel wall accounts for some of the cause of the thrombosis but blood constituents also play a role. We hypothesized that levels of soluble P-selectin (sP-sel, a marker of platelet activation), von Willebrand factor (vWf, an index of endothelial damage/dysfunction), tissue factor (TF, a coagulation protein involved in the 'extrinsic' coagulation pathway) and fibrinogen would be abnormally elevated in relation to disease severity and correlated with each other, and related to ethnicity, in a multiethnic population of patients with PAD. To test this hypothesis, we studied 234 patients (80% white, 7% Indo-Asian, 13% Afro-Caribbean) with confirmed PAD [ankle brachial pressure index (ABPI)< or =0.8] and 50 healthy controls. All of the indices studied were increased in patients over controls (p<0.05). None of the indices of the hypercoagulable state were significantly different between the three ethnic groups studied. Patients with ischaemic rest pain were shown to have higher levels of plasma fibrinogen (p<0.001) although none of the other prothrombotic markers were increased in this group. Furthermore, fibrinogen was higher in cases whose ABPI was below the median (<0.52) when compared to those less severely affected, with an inverse correlation between fibrinogen and ABPI (Spearman, r=-0.178, p=0.009). In conclusion, we found a prothrombotic state in patients with PAD with increased levels of markers of endothelial damage/dysfunction, platelet activation and thrombosis, which may contribute to the pathogenesis of this condition. However, disease severity was only related to plasma fibrinogen levels.

Antihypertensive drug therapy and the risk of lower extremity amputations in pharmacologically treated type 2 diabetes patients

PURPOSE

The objective of this study was to determine the association between different antihypertensive drug therapies and lower extremity amputations (LEAs) in type 2 diabetes patients.

METHODS

Data were obtained from the PHARMO Record Linkage System comprising pharmacy records and data on hospitalisations for all 450,000 residents of eight Dutch cities. In a nested case-control study among 12,140 type 2 diabetes patients who used antihypertensive drugs, 26 cases with a first LEA and 94 controls without a LEA matched on age, sex and calendar time were identified. Logistic regression was used to estimate the relative risk of LEA and to adjust for potential confounding factors.

RESULTS

Among type 2 diabetes patients who used antihypertensive drugs, subjects who used thiazide diuretics, alone or in combination, had a higher risk of LEA compared to subjects who used Angiotensin Converting Enzyme (ACE) inhibitor monotherapy (crude odds ratio (OR): 6.11 [95% confidence interval (CI): 1.32-28.27]). The use of thiazide diuretics was also associated with an increased risk of LEA when compared to the use of any non-thiazide antihypertensive drug (adjusted OR: 7.04 [1.10-45.30]). The increased risk of LEA associated with the use of thiazides compared to the use of non-thiazides depended on the duration of use (adjusted OR(< or = 365 days), 4.82 [0.61-38.34] and adjusted OR(>365 days), 26.16 [1.02-674.02], p-trend = 0.01).

CONCLUSIONS

Treatment with thiazide diuretics compared to treatment with other antihypertensive drugs was associated with excess amputations in type 2 diabetes patients. Due to several limitations of this study, our findings do not preclude the use of thiazides in type 2 diabetes mellitus patients as yet.

Pulse Pressure as a Risk Factor for Peripheral Vascular Disease in Type 2 Diabetic Patients

This study examined whether pulse pressure (PP) could be an independent predictor and associated with severity of peripheral vascular disease (PVD) in 396 type 2 diabetic patients (143 men and 253 women, aged 64.1 +/- 11.2 years). Peripheral vascular disease was diagnosed by an ankle-brachial index (ABI) < 0.90 and as severe PVD if ABI < 0.80. Association was evaluated before and after adjustment for age, sex, diabetes duration, hypertension, smoking, fasting plasma glucose (FPG), total cholesterol (TC), usage of insulin, and usage of angiotensin-converting enzyme inhibitors (ACEI) or angiotensin receptor blockers (ARB); and for systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP), respectively. Results showed that PP increased from no (n = 348) to mild (n = 25) and severe (n = 23) PVD (one-way ANOVA, p < 0.001; multiple comparisons, p < 0.05 for any two groups). The PP increase from no to mild PVD was due to SBP increase; while further increase to severe PVD was due to both DBP drop and an even higher SBP. Adjusted odds ratio (AOR) for PVD for every 1-mmHg PP increment was 1.035 (1.012-1.058). When PP was categorized as tertiles (< 50, 50-59 and > or = 60 mmHg), respective AOR for PVD for second and third vs. first tertile was 2.605 (1.008-6.729) and 2.835 (1.123-7.156). Pulse pressure was also predictive for ABI independent of the effects of the confounders and the other parameters of blood pressure. In conclusion, PP was an independent predictor and correlated with severity of PVD in type 2 diabetic patients.

Effect of beta-blockers on peripheral skin microcirculation in hypertension and peripheral vascular disease

OBJECTIVE

This study was undertaken to investigate the possible negative effect of beta-blockers on skin microcirculation in patients with intermittent claudication and hypertension. Methods and materials In this clinical crossover study, 20 patients with mild to moderate hypertension, treated with long-term beta-blockade, and intermittent claudication or ischemic rest pain, underwent assessment of peripheral circulation before and after 2-week withdrawal of beta-blocking therapy and again 2 weeks after restarting therapy. Replacement therapy (calcium antagonist) was given if considered necessary to control hypertension. Skin microcirculation was assessed with three noninvasive techniques: capillary microscopy of the hallux nailfold, transcutaneous oximetry of the forefoot, and laser Doppler fluxmetry of the great toe.

RESULTS

Mean initial blood pressure was 163/81 mm Hg. Mean heart rate significantly increased with withdrawal of beta-blocker, from 65 bpm to 85 bpm. No significant differences in skin microcirculation and blood pressure were found between measurements obtained before, during, and after withdrawal of beta-blocking therapy. Patients experienced no change in symptoms during the study.

CONCLUSION

beta-Blockers do not appear to have a negative effect on peripheral skin microcirculation and are therefore not contraindicated to treat hypertension when intermittent claudication or ischemic rest pain is also present.

Serum uric acid in hypertensive patients with and without peripheral arterial disease

BACKGROUND

Uric acid is frequently elevated in hypertension. In addition to renal and metabolic disturbances, lower limb ischemia might contribute to hyperuricemia among hypertensives complicated by peripheral arterial disease (PAD).

OBJECTIVE

To test the hypothesis that uric acid status is related to lower limb function in hypertensives with PAD.

METHODS

Serum and 24-h urine uric acid levels and other risk factors were examined in 145 hypertensives free of PAD and 166 hypertensives with PAD. Ankle/brachial index (ABI) and absolute claudication distance (in PAD) on a treadmill test (ACD) were assessed.

RESULTS

In multiple regression analysis for serum uric acid in the total group, PAD emerged as an independent determinant (P=0.03) next to age (P=0.005), triglycerides (P=0.04), and insulin (P=0.02). Serum uric acid concentrations were higher in hypertensives with PAD (404+/-101 vs. 347+/-80 micromol/l, P<0.001) independent of components of the metabolic syndrome (body mass index, triglycerides, insulin) and of age, gender, diabetes mellitus, pulse pressure, cholesterol, C-reactive protein, and treatment. After adjustment for kidney function by uric acid/creatinine ratio, values remained higher in hypertensives with PAD (P=0.01). Uric acid excretion was higher in the PAD group (P<0.001), whereas uric acid clearance was comparable between both groups. In multiple regression analysis for ACD (357+/-183 m) in the PAD group, serum uric acid (P=0.02), C-reactive protein (P<0.0001), age (P=0.02), and smoking (P=0.004) were independently associated. ABI (0.62+/-0.17) was not related to uric acid in PAD patients.

CONCLUSION

Hyperuricemia is more pronounced in hypertensives complicated by PAD and is associated with worse functional status of the peripheral circulation.

Treatment of hypertension in peripheral arterial disease

BACKGROUND

Peripheral arterial disease (PAD) causes considerable morbidity and mortality. Hypertension is a risk factor for PAD. Therefore, treatment for hypertension must be compatible with the symptoms of PAD. Controversy regarding the effects of beta blockade for hypertension in patients with PAD has led many physicians to stop prescribing beta-blockers. Little is known about the effects of other classes of anti-hypertensive drugs in the presence of PAD.

OBJECTIVES

To determine the effects of anti-hypertensive drugs on the: cardiovascular events and death in patients with hypertension and PAD; symptoms of claudication and critical leg ischaemia; progression of PAD, and revascularisation, or amputations.

SEARCH STRATEGY

Trials were sought via the Specialised Register of the Cochrane Peripheral Vascular Diseases Group (last searched July 2003), the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 2, 2003), and the NHS Database of Abstracts of Reviews of Effectiveness (DARE) (last searched August 2002). There were no language restrictions. Abstracts of cardiology meetings were studied. Reference lists of papers were also examined.

SELECTION CRITERIA

Randomised controlled trials of at least one anti-hypertensive treatment against placebo, or two anti-hypertensive medications against each other, with interventions lasting at least one month. Trials had to include patients with symptomatic PAD. Trials of poor quality and execution were excluded, as were cross-over trials.

DATA COLLECTION AND ANALYSIS

Data were extracted by one reviewer and checked by the other. Eligible studies were excluded when presentation prevented adequate extraction of data, and enquiries to authors did not yield the raw data.

MAIN RESULTS

Two studies were included in the review. In one trial using perindopril in small numbers of patients with PAD, there was a marginal increase in claudication distance (weighted mean difference (WMD) 8.0, 95% confidence interval (CI) -30.66 to 46.66), but no change in ankle brachial pressure index (ABPI), (WMD 0, 95% CI -0.14 to 0.14), and a reduction in walking distance (WMD -46, 95 % CI -169.24 to 77.24). In patients undergoing angioplasty, a second trial suggested that the calcium antagonist verapamil reduced restenosis, although this was not reflected in the maintenance of a high ABPI.

REVIEWER'S CONCLUSIONS

The evidence for various anti-hypertensive drug classes in PAD is poor, so that it is unknown whether significant benefit or risk accrues from their use. In view of this, no definite recommendations on use or avoidance can be made from the available data.