Increased serum N-terminal pro-B-type natriuretic peptide levels in patients with medial arterial calcification and poorly compressible leg arteries

Association between high-sensitivity cardiac troponin I and fall-related hospitalisation in women aged over 70 years

OBJECTIVE

To examine the association between high-sensitivity cardiac troponin I (hs-cTnI), a biomarker of myocardial injury, muscle function decline and 14.5-year fall-related hospitalisation risk in women aged over 70 years.

METHODS

1179 ambulatory community-dwelling women aged over 70 years with subclinical levels of hs-cTnI (ie, <15.6 ng/L), who were followed up for 14.5 years, were included. Samples for hs-cTnI were obtained in 1998. Fall-related hospitalisations were retrieved from linked health records. Muscle function measures, including handgrip strength and the Timed-Up-and-Go (TUG) test, were assessed in 1998 and 2003.

RESULTS

Mean±SD age was 75.2±2.7 years. Over 14.5 years of follow-up, 40.4% (476 of 1179) experienced fall-related hospitalisation. Participants were categorised into four approximate hs-cTnI quartiles: quartile 1 (<3.6 ng/L), quartile 2 (3.6-4.4 ng/L), quartile 3 (4.5-5.8 ng/L) and quartile 4 (≥5.9 ng/L). Compared with those in Q1, women in Q4 were likely to experience fall-related hospitalisation (36.0% vs 42.8%). In a multivariable-adjusted model that accounted for CVD and fall risk factors, compared with women in Q1, those in Q4 had a 46% higher risk of fall-related hospitalisation (HR 1.46, 95% CI 1.08 to 1.98). Additionally, women in Q4 had slower TUG performance compared with those in Q1 (10.3 s vs 9.5 s, p=0.032).

CONCLUSION

Elevated level of hs-cTnI was associated with slower TUG performance and increased fall-related hospitalisation risk. This indicates subclinical level of hs-cTnI can identify clinically relevant falls, emphasising the need to consider cardiac health during fall assessment in women aged over 70 years.

TRIAL REGISTRATION NUMBER

ACTRN12617000640303.

Mönckeberg's medial calcific sclerosis in diabetic and non-diabetic foot infections

The aim of this study was to evaluate the prevalence and extent of lower extremity Mönckeberg's Medial Calcific Sclerosis (MMCS) in patients with and without diabetes in patients admitted to the hospital for foot infections. This study retrospectively reviewed 446 patients admitted to the hospital with a moderate or severe foot infection. We defined diabetes based on ADA criteria and reviewed electronic medical records for demographics, medical history and physical examination data. Anterior-posterior and lateral foot radiographs were examined to identify the presence and extent of vascular calcification. We categorised MMCS based on anatomical location: ankle joint to the navicular-cuneiform joint, Lis Franc joint to metatarsophalangeal joints and distal to the metatarsophalangeal joints. The prevalence of MMCS was 40.6%. The anatomic extent of MMCS was 19.3% in the toes, 34.3% in the metatarsals and 40.6% in the hindfoot/ankle. Calcification was not common solely in the dorsalis pedis artery (DP) (3.8%) or solely in the posterior tibial artery (PT) (7.0%). Usually, both DP and PT arteries were affected by MMCS (29.8%). The prevalence of MMCS was higher in people with diabetes (in hindfoot and ankle [50.1% vs. 9.9%, p ≤ 0.01]; metatarsals [42.6% vs. 5.9%, p ≤ 0.01]; and toes [23.8% vs. 4.0%, p ≤ 0.01]). People with diabetes were 8.9 (CI: 4.5-17.8) times more likely to have MMCS than those without diabetes. This is a group that often has poor perfusion and needs vascular assessment. The high prevalence of MMCS raises questions about the reliability of the conventional segmental arterial Doppler studies to diagnose PAD.

Old and Novel Predictors for Cardiovascular Risk in Diabetic Foot Syndrome—A Narrative Review

Diabetic foot syndrome (DFS) is a complication associated with diabetes that has a strong negative impact, both medically and socio-economically. Recent epidemiological data show that one in six patients with diabetes will develop an ulcer in their lifetime. Vascular complications associated with diabetic foot have multiple prognostic implications in addition to limiting functional status and leading to decreased quality of life for these patients. We searched the electronic databases of PubMed, MEDLINE and EMBASE for studies that evaluated the role of DFS as a cardiovascular risk factor through the pathophysiological mechanisms involved, in particular the inflammatory ones and the associated metabolic changes. In the era of evidence-based medicine, the management of these cases in multidisciplinary teams of “cardio-diabetologists” prevents the occurrence of long-term disabling complications and has prognostic value for cardiovascular morbidity and mortality among diabetic patients. Identifying artificial-intelligence-based cardiovascular risk prediction models or conducting extensive clinical trials on gene therapy or potential therapeutic targets promoted by in vitro studies represent future research directions with a modulating role on the risk of morbidity and mortality in patients with DFS.

An elevated ankle-brachial index is not a valid proxy for peripheral medial arterial calcification

BACKGROUND AND AIMS

The ankle brachial index (ABI) is often used as a proxy for medial arterial calcification (MAC) in studies investigating MAC as a cardiovascular risk factor, but evidence supporting this hypothesis is sparse. This study aims to investigate the use of an elevated ABI as proxy for MAC, as visualized with computed tomography (CT).

METHODS

Cross-sectional data of 718 participants with, or at risk of cardiovascular disease was used. The ABI was calculated using cutoffs >1.4 and > 1.3. The presence of MAC was assessed in the crural and femoral arteries by CT imaging. Modified Poisson regression was used to assess the association between an elevated ABI and the presence of MAC, and test characteristics were calculated.

RESULTS

MAC was found in 25.0% of participants. An ABI >1.4 was found in 8.7% of participants, of whom 45.2% had MAC. An elevated ABI was significantly associated with the presence of MAC (RR 1.74, CI: 1.26-2.40). However, poor positive specific agreement (23.3%, CI: 13.9-34.3), sensitivity (15.7%, CI: 10.4-21.1) and positive predictive value (45.2%, CI: 32.8-57.5) were found. Despite good specificity (93.6%, CI: 91.6-95.7) the area under the receiving operator curve remained poor (54.7%, CI: 51.8-57.6). Negative specific agreement (84.5%, CI: 81.4-87.0) and negative predictive value (77.0%, CI: 73.7-80.2) were acceptable.

CONCLUSIONS

An elevated ABI is insufficient to serve as a true diagnostic proxy for MAC. Studies that have drawn conclusions on the association between MAC and cardiovascular disease, solely based on the ABI, are likely to underestimate the found effects.

Role of Selected miRNAs as Diagnostic and Prognostic Biomarkers in Cardiovascular Diseases, Including Coronary Artery Disease, Myocardial Infarction and Atherosclerosis

Cardiovascular diseases are the leading cause of death worldwide in different cohorts. It is well known that miRNAs have a crucial role in regulating the development of cardiovascular physiology, thus impacting the pathophysiology of heart diseases. MiRNAs also have been reported to be associated with cardiac reactions, leading to myocardial infarction (MCI) and ultimately heart failure (HF). To prevent these heart diseases, proper and timely diagnosis of cardiac dysfunction is pivotal. Though there are many symptoms associated with an irregular heart condition and though there are some biomarkers available that may indicate heart disease, authentic, specific and sensitive markers are the need of the hour. In recent times, miRNAs have proven to be promising candidates in this regard. They are potent biomarkers as they can be easily detected in body fluids (blood, urine, etc.) due to their remarkable stability and presence in apoptotic bodies and exosomes. Existing studies suggest the role of miRNAs as valuable biomarkers. A single biomarker may be insufficient to diagnose coronary artery disease (CAD) or acute myocardial infarction (AMI); thus, a combination of different miRNAs may prove fruitful. Therefore, this review aims to highlight the role of circulating miRNA as diagnostic and prognostic biomarkers in cardiovascular diseases such as coronary artery disease (CAD), myocardial infarction (MI) and atherosclerosis.

Arterial endothelial function, carotid artery intima-media thickness and abdominal aortic calcification in diabetic and nondiabetic CKD stage 4-5 patients not on dialysis

AIMS

We aimed to study the effect of diabetes (DM) on endothelial dysfunction assessed by flow-mediated vasodilatation (FMD), carotid intima-media thickness (cIMT) and abdominal aortic calcification score (AAC) in chronic kidney disease (CKD) stage 4-5 patients not on dialysis.

METHODS

Altogether 199 non-dialysis CKD stage 4-5 patients enrolled in the Chronic Arterial Disease, quality of life and mortality in chronic KIDney injury (CADKID) study with plain lumbar radiograph for the assessment of AAC were included. Data on cIMT and FMD were available for 172 and 161 patients, respectively.

RESULTS

Median age was 65 (IQR 54-76) years, 88 (44.2%) patients had DM and median eGFR was 12 (IQR 10-14) ml/min/1.73 m² in the study. FMD [controls: 3.3(2.0-6.7)% vs. DM-patients: 4.3(1.3-6.6)%, p = 0.73] and cIMT [controls: 0.65(0.58-0.87)mm vs. DM-patients: 0.67(0.59-0.81)mm, p = 0.65], were similar between the groups. AAC was higher in patients with DM [controls: 5(1-9) vs. DM-patients: 7(2-13), p = 0.01]. The significant multivariate determinants for AAC were older age (β = 0.22, p < 0.0001), pulse pressure (β = 0.05, p < 0.0001), DM (β = 1.33, p = 0.04) and ProBNP (per µg/l β = 0.18, p = 0.0008). AAC and cIMT were associated with incident cardiovascular death independent of DM.

CONCLUSIONS

DM is associated with increased AAC but not increased cIMT or attenuated FMD in advanced CKD patients.

Diffuse Hepatosplenic 99mTc-Pyrophosphate Activity Caused by Amyloidosis

A 46-year-old man underwent Tc-pyrophosphate scan to evaluate possible infiltrative myocardiopathy revealed by echocardiography. The images did not show abnormal cardiac activity. However, diffuse abnormal activity in the liver and spleen was noted. Pathological examination from the specimen acquired from hepatic biopsy demonstrated amyloidosis, light chain type.

Inflammatory Mediators Across the Spectrum of Ankle-Brachial Index

Aim: Peripheral artery disease (PAD) is a manifestation of atherosclerosis with poor prognosis. It is generally complicated by vascular calcification, which is located either in the intima as patchy infiltrates; or circumferentially in the media, also known as medial arterial calcification (MAC). Obstructive PAD is reflected by low anklebrachial index (ABI ≤ 0.9), whereas MAC is revealed by high ABI (ABI > 1.4). Considering the increase in cardiovascular mortality at both ends of the ABI spectrum, this study aimed to explore the underlying pathology through cytokines with established prognostic significance; namely pentraxin-3(PTX3), high sensitivity C-reactive protein (hsCRP), copeptin, soluble triggering receptor expressed on myeloid cells-1 (sTREM-1), NT-proBNP, and neopterin.

Methods: We categorized 180 patients with previous multivessel coronary artery bypass grafting surgery into three groups based on their ABI measurements; 60 patients with ABI ≤ 0.9, 60 patients with ABI within 0.91 and 1.4 (normal ABI), and 60 patients with ABI > 1.4 constituted the “PAD,” “normal,” “MAC” groups, respectively. The circulating levels of the biochemical markers were determined.

Results: In the PAD group, the cytokine levels with predominantly proatherogenic actions such as PTX3, hsCRP, copeptin, and sTREM-1 were increased and these cytokine levels declined as the ABI increased. In the MAC group, the cytokine concentrations with pleiotropic actions such as NT-proBNP and neopterin increased and; NT-proBNP and neopterin concentrations decreased as ABI decreased. The linear regression analysis revealed that neopterin (β = 0.72), PTX3 (β = −0.32), and copeptin (β = −0.48) were independent predictors of ABI.

Conclusions: These findings suggest that different inflammatory pathways influence the pathology at the opposing ends of the ABI spectrum. Consequently, we suggest that PTX3, copeptin, and neopterin are promising biomarkers for future research.

Association of N-Terminal Pro B-Type Natriuretic Peptide With Blood Pressure and Pulse Pressure in Elderly People - A Cross-Sectional Population Study

BACKGROUND

N-Terminal pro B-type natriuretic peptide (NT-proBNP) is widely used as a marker of ventricular dysfunction. However, data regarding the association of NT-proBNP with blood pressure (BP) and pulse pressure (PP) in the elderly population are limited.Methods and Results:The present cross-sectional study involved 6,529 participants, aged ≥70 years, without cardiovascular disease (CVD), who underwent general health examinations. Serum NT-proBNP concentrations were determined, with high NT-proBNP concentrations defined as those ≥125 pg/mL. Subjects were divided into five groups based on PP (<50, ≥50 to <60, ≥60 to <70, ≥70 to <80, and ≥80 mmHg). NT-proBNP was positively associated with systolic BP, whereas a U-shaped association was found between diastolic BP and NT-proBNP. The odds ratios for high NT-proBNP concentrations in the PP ≥80 and ≥70 to <80 mmHg groups (OR 1.83 [P<0.001] and 1.40 [P<0.005], respectively) were significantly higher than in the PP <50 mmHg group. All data were adjusted for age, sex, body mass index, hemoglobin concentration, serum creatinine, pulse rate, smoking, alcohol intake, and antihypertensive medication intake, and the presence of diabetes and dyslipidemia.

CONCLUSIONS

The results suggest that NT-proBNP concentrations may be a marker of not only ventricular dysfunction, but also arterial stiffness in the elderly population without CVD.

Vitamin K-Dependent Protein Activity and Incident Ischemic Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis

OBJECTIVE

Vitamin K-dependent proteins (VKDPs), which require post-translational modification to achieve biological activity, seem to contribute to thrombus formation, vascular calcification, and vessel stiffness. Whether VKDP activity is prospectively associated with incident cardiovascular disease has not been studied.

APPROACH AND RESULTS

VKDP activity was determined by measuring circulating des-γ-carboxy prothrombin concentrations in a random sample of 709 multiethnic adults free of cardiovascular disease drawn from the Multi-Ethnic Study of Atherosclerosis (MESA). Lower des-γ-carboxy prothrombin concentrations reflect greater VKDP activity. Subjects were followed up for the risk of ischemic cardiovascular disease (coronary heart disease, stroke, and fatal cardiovascular disease) for 11.0 years of follow-up. A total of 75 first ischemic CVD events occurred during follow-up. The incidence of ischemic cardiovascular disease increased progressively across des-γ-carboxy prothrombin quartiles, with event rates of 5.9 and 11.7 per 1000 person-years in the lowest and highest quartiles. In analyses adjusted for traditional cardiovascular risk factors and measures of vitamin K intake, a doubling of des-γ-carboxy prothrombin concentration was associated with a 1.53 (95% confidence interval, 1.09-2.13; P=0.008) higher risk of incident ischemic cardiovascular disease. The association was consistent across strata of participants with diabetes mellitus, hypertension, renal impairment, and low vitamin K nutritional intake.

CONCLUSIONS

In this sample of middle-aged and older adults, VKDP activity was associated with incident ischemic cardiovascular events. Further studies to understand the role of this large class of proteins in cardiovascular disease are warranted.

A review of the pathophysiology and potential biomarkers for peripheral artery disease

Peripheral artery disease (PAD) is due to the blockage of the arteries supplying blood to the lower limbs usually secondary to atherosclerosis. The most severe clinical manifestation of PAD is critical limb ischemia (CLI), which is associated with a risk of limb loss and mortality due to cardiovascular events. Currently CLI is mainly treated by surgical or endovascular revascularization, with few other treatments in routine clinical practice. There are a number of problems with current PAD management strategies, such as the difficulty in selecting the appropriate treatments for individual patients. Many patients undergo repeated attempts at revascularization surgery, but ultimately require an amputation. There is great interest in developing new methods to identify patients who are unlikely to benefit from revascularization and to improve management of patients unsuitable for surgery. Circulating biomarkers that predict the progression of PAD and the response to therapies could assist in the management of patients. This review provides an overview of the pathophysiology of PAD and examines the association between circulating biomarkers and PAD presence, severity and prognosis. While some currently identified circulating markers show promise, further larger studies focused on the clinical value of the biomarkers over existing risk predictors are needed.

Calcification Propensity and Survival among Renal Transplant Recipients

Calciprotein particle maturation time (T50) in serum is a novel measure of individual blood calcification propensity. To determine the clinical relevance of T50 in renal transplantation, baseline serum T50 was measured in a longitudinal cohort of 699 stable renal transplant recipients and the associations of T50 with mortality and graft failure were analyzed over a median follow-up of 3.1 years. Predictive value of T50 was assessed for patient survival with reference to traditional (Framingham) risk factors and the calcium-phosphate product. Serum magnesium, bicarbonate, albumin, and phosphate levels were the main determinants of T50, which was independent of renal function and dialysis vintage before transplant. During follow-up, 81 (12%) patients died, of which 38 (47%) died from cardiovascular causes. Furthermore, 45 (6%) patients developed graft failure. In fully adjusted models, lower T50 values were independently associated with increased all-cause mortality (hazard ratio, 1.43; 95% confidence interval, 1.11 to 1.85; P=0.006 per SD decrease) and increased cardiovascular mortality (hazard ratio, 1.55; 95% confidence interval, 1.04 to 2.29; P=0.03 per SD decrease). In addition to age, sex, and eGFR, T50 improved prognostication for all-cause mortality, whereas traditional risk factors or calcium-phosphate product did not. Lower T50 was also associated with increased graft failure risk. The associations of T50 with mortality and graft failure were confirmed in an independent replication cohort. In conclusion, reduced serum T50 was associated with increased risk of all-cause mortality, cardiovascular mortality, and graft failure and, of all tested parameters, displayed the strongest association with all-cause mortality in these transplant recipients.

Associations of candidate biomarkers of vascular disease with the ankle-brachial index and peripheral arterial disease

BACKGROUND

The use of multiple biomarkers representing various etiologic pathways of atherosclerosis may improve the prediction of interindividual variation in the ankle-brachial index (ABI). To this end, we investigated associations of 47 candidate biomarkers with the ABI and presence of peripheral arterial disease (PAD) in African-Americans (AAs) and non-Hispanic whites (NHWs).

METHODS

Study participants included 1,291 AAs (71.1% women, mean age, 63.4±9.3 years) and 1,152 NHWs (57.5% women, mean age 58.5±10.1 years) belonging to hypertensive sibships. Peripheral arterial disease was defined as an ABI ≤ 0.90. Circulating levels of 47 candidate biomarkers were log-transformed before analysis because of skewed distribution. Multivariate regression analyses were used to identify biomarkers associated with ABI or PAD independently of age, sex, conventional risk factors, and medication use.

RESULTS

After adjustment for covariates, higher levels of nine biomarkers were associated with a lower ABI in AAs (all P ≤ 0.005); these biomarkers were C-reactive protein (CRP), interleukin-6, tumor necrosis factor receptor-II (TNF-R II), lipoprotein(a), N-terminal pro-brain natriuretic peptide (NT-proBNP), pro-atrial natriuretic peptide, C-terminal pro-arginine vasopressin, osteoprotegerin, and fibrinogen. Three biomarkers - myeloperoxidase, NT-proBNP, and D-dimer - were associated with ABI in NHWs (all P ≤ 0.01). C-reactive protein, interleukin-6, TNF-R II, lipoprotein(a), NT-proBNP, pro-atrial natriuretic peptide, D-dimer, and fibrinogen were associated with PAD (all P ≤ 0.005) in AAs after adjustment for covariates. None of the biomarkers were independently associated with PAD in NHWs.

CONCLUSION

A multimarker approach improved the prediction of interindividual variation in the ABI in AAs and NHWs, and improved prediction of the presence of PAD in AAs.

Presence of Diastolic Dysfunction in Patients With Peripheral Artery Disease

Peripheral artery disease (PAD) and heart failure (HF) share many risk factors; however, the prevalence and characteristics of HF in patients with PAD have not been fully examined. We investigated 120 consecutive patients with PAD, defined by an ankle-brachial index ≤0.9. In all, 36 (30%) patients had brain natriuretic peptide (BNP) levels ≥100 pg/mL (high BNP group), and 84 (70%) patients had BNP levels <100 pg/mL (low BNP group). Univariate analysis showed that high BNP was associated with age, estimated glomerular filtration rate, hypertension, and transmitral E-wave/early diastolic mitral annular velocity (E/e′) ratio. Multivariate logistic regression analysis established that a high BNP was strongly and independently associated with the highest quartile of E/e′, highlighting these patients’ diastolic dysfunction. The prevalence of high BNP levels in patients with PAD suggests that routine BNP measurements might be useful to detect HF.

Endothelial actions of atrial and B-type natriuretic peptides

The cardiac hormone atrial natriuretic peptide (ANP) is critically involved in the maintenance of arterial blood pressure and intravascular volume homeostasis. Its cGMP-producing GC-A receptor is densely expressed in the microvascular endothelium of the lung and systemic circulation, but the functional relevance is controversial. Some studies reported that ANP stimulates endothelial cell permeability, whereas others described that the peptide attenuates endothelial barrier dysfunction provoked by inflammatory agents such as thrombin or histamine. Many studies in vitro addressed the effects of ANP on endothelial proliferation and migration. Again, both pro- and anti-angiogenic properties were described. To unravel the role of the endothelial actions of ANP in vivo, we inactivated the murine GC-A gene selectively in endothelial cells by homologous loxP/Cre-mediated recombination. Our studies in these mice indicate that ANP, via endothelial GC-A, increases endothelial albumin permeability in the microcirculation of the skin and skeletal muscle. This effect is critically involved in the endocrine hypovolaemic, hypotensive actions of the cardiac hormone. On the other hand the homologous GC-A-activating B-type NP (BNP), which is produced by cardiac myocytes and many other cell types in response to stressors such as hypoxia, possibly exerts more paracrine than endocrine actions. For instance, within the ischaemic skeletal muscle BNP released from activated satellite cells can improve the regeneration of neighbouring endothelia. This review will focus on recent advancements in our understanding of endothelial NP/GC-A signalling in the pulmonary versus systemic circulation. It will discuss possible mechanisms accounting for the discrepant observations made for the endothelial actions of this hormone-receptor system and distinguish between (patho)physiological and pharmacological actions. Lastly it will emphasize the potential therapeutical implications derived from the actions of NPs on endothelial permeability and regeneration.

Survival in patients with poorly compressible leg arteries

OBJECTIVES

This study sought to compare survival of patients with poorly compressible arteries (PCA) to those with a normal ankle-brachial index (ABI) and those with peripheral arterial disease (PAD).

BACKGROUND

Limited data are available regarding survival in patients with PCA identified in the clinical setting by noninvasive lower extremity arterial evaluation.

METHODS

We conducted a historical cohort study of consecutive patients who underwent outpatient, noninvasive lower extremity arterial evaluation at the Mayo Clinic, Rochester, Minnesota, from January 1998 through December 2007, and who were followed for a mean duration of 5.8 ± 3.1 years. An ABI 1.00 to 1.30 was considered normal, PAD was defined as a resting or post-exercise ABI ≤0.90, and PCA defined as an ABI ≥1.4 and/or an ankle systolic blood pressure >255 mm Hg. Patients were followed for all-cause mortality through September 30, 2009.

RESULTS

Of 16,493 individuals (mean age 67.8 ± 13.0 years, 59% male); 29% had normal ABI, 54% had PAD, and 17% had PCA. During follow-up (mean duration 5.8 ± 3.1 years), 4,365 patients (26%) died. The percent alive at the end of the study period was 88%, 70%, and 60% for normal ABI, PAD, and PCA, respectively. After adjustment for age, sex, cardiovascular risk factors, comorbid conditions, and medication use, the hazard ratios (95% confidence intervals) of death associated with PCA were 2.0 (1.8 to 2.2) and 1.3 (1.2 to 1.4) compared with the normal ABI and PAD groups, respectively.

CONCLUSIONS

Patients identified by noninvasive vascular testing to have poorly compressible leg arteries have poor survival, worse than those with a normal ABI or those with PAD.

Serum N-terminal pro-B-type natriuretic peptide levels are associated with functional capacity in patients with peripheral arterial disease

We hypothesized that higher serum levels of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) are associated with lower functional capacity in patients with peripheral arterial disease ([PAD] n = 481, mean age 67, 68% men). Functional capacity was quantified as distance walked on a treadmill for 5 minutes. Patients were divided into 3 groups according to the distance walked: >144 yards (group 1, n = 254); 60 to 144 yards (group 2, n = 80); <60 yards or did not walk (group 3, n = 147). The association between NT-pro-BNP levels and the ordinal 3-level walking distance was assessed using multivariable ordinal logistic regression analyses that adjusted for several possible confounding variables. Higher levels of NT-pro-BNP were associated with a lower ordinal walking category independent of possible confounders (odds ratio [OR] 1.51, 95% confidence interval [CI] 1.28-1.77; P < .001). In conclusion, higher levels of NT-pro-BNP are independently associated with lower functional capacity in patients with PAD and may be a marker of hemodynamic stress in these patients.

Usefulness of red cell distribution width to predict mortality in patients with peripheral artery disease

Increased red blood cell distribution width (RDW), a marker of anisocytosis, has been associated with adverse outcomes in multiple settings. Whether RDW is predictive of mortality in patients with peripheral artery disease (PAD) is unknown. We studied 13,039 consecutive outpatients (69.5 ± 12.0 years of age, 60.9% men, 97.6% white) with PAD identified by noninvasive lower-extremity arterial testing at the Mayo Clinic from January 1997 through December 2007, with follow-up through September 2009. We defined PAD as a low (≤ 0.9) or high (≥ 1.4) ankle-brachial index (ABI). Cardiovascular risk factors and co-morbidities were ascertained using electronic medical record-based algorithms. RDW was obtained from the complete blood cell count drawn around the time of arterial evaluation. Mortality was ascertained using the Mayo electronic medical record and Accurint databases. Association of RDW with all-cause mortality was analyzed by multivariable Cox proportional hazards regression. During a median follow-up of 5.5 years, 4,039 (31.0%) deaths occurred (28.7% in low and 38.9% in high ABI subsets). After adjustment for age, gender, cardiovascular risk factors, and co-morbidities, patients in the highest quartile of RDW (> 14.5%) had a 66% greater risk of mortality compared to the lowest quartile (< 12.8%, p < 0.0001); a 1% increment in RDW was associated with a 10% greater risk of all-cause mortality (hazard ratio 1.10, 95% confidence interval 1.08 to 1.12, p < 0.0001). The adjusted hazard ratio was similar in the low (1.10, 1.08 to 1.12) and high (1.09, 1.06 to 1.12) ABI subsets. In conclusion, RDW, a routinely available measurement, is an independent prognostic marker in patients with PAD.