Contribution of the ankle-brachial index to improve the prediction of coronary risk: The ARTPER cohort

Assessment of Subclinical Atherosclerosis in Asymptomatic People In Vivo: Measurements Suitable for Biomarker and Mendelian Randomization Studies

BACKGROUND

One strategy to reduce the burden of cardiovascular disease is the early detection and treatment of atherosclerosis. This has led to significant interest in studies of subclinical atherosclerosis, using different phenotypes, not all of which are accurate reflections of the presence of asymptomatic atherosclerotic plaques. The aim of part 2 of this series is to provide a review of the existing literature on purported measures of subclinical disease and recommendations concerning which tests may be appropriate in the prevention of incident cardiovascular disease.

METHODS

We conducted a critical review of measurements used to infer the presence of subclinical atherosclerosis in the major conduit arteries and focused on the predictive value of these tests for future cardiovascular events, independent of conventional cardiovascular risk factors, in asymptomatic people. The emphasis was on studies with >10 000 person-years of follow-up, with meta-analysis of results reporting adjusted hazard ratios (HRs) with 95% CIs. The arterial territories were limited to carotid, coronary, aorta, and lower limb arteries.

RESULTS

In the carotid arteries, the presence of plaque (8 studies) was independently associated with future stroke (pooled HR, 1.89 [1.04-3.44]) and cardiac events (7 studies), with a pooled HR, 1.77 (1.19-2.62). Increased coronary artery calcium (5 studies) was associated with the risk of coronary heart disease events, pooled HR, 1.54 (1.07-2.07) and increasing severity of calcification (by Agaston score) was associated with escalation of risk (13 studies). An ankle/brachial index (ABI) of <0.9, the pooled HR for cardiovascular death from 7 studies was 2.01 (1.43-2.81). There were insufficient studies of either, thoracic or aortic calcium, aortic diameter, or femoral plaque to synthesize the data based on consistent reporting of these measures.

CONCLUSIONS

The presence of carotid plaque, coronary artery calcium, or abnormal ankle pressures seems to be a valid indicator of the presence of subclinical atherosclerosis and may be considered for use in biomarker, Mendelian randomization and similar studies.

Prognostic Value of Ankle-Brachial Index in Prediction of Cardiovascular Events in an Asian Population with Multiple Atherosclerotic Risk Factors

We aimed to evaluate the incremental prognostic value after incorporation of the ankle-brachial index (ABI) into the 10-year pool cohort equation (PCE) risk model in patients with multiple risk factors (MRFs). A total of 4332 MRFs patients were divided into 2 groups as ABI ≤.9 or >.9. The primary outcome was hard cardiovascular events (hCVE: including cardiovascular death, myocardial infarction, or ischemic stroke) over a median follow-up of 36 months. The Cox proportional hazards survival model, C-statistic, and net reclassification indices (NRI) were used. The occurrence of the primary outcome in the ABI ≤.9 group (3.7%) was significantly greater than in the ABI > .9 group (1.3%), P < .001. ABI is an independent predictor of hCVE in addition to the variables in the standard risk model (age, gender, and smoking status). ABI modestly improved the C-index when added to the PCE risk model (PCE .70 vs ABI+PCE .74). The addition of ABI to the PCE risk model did not significantly improve the classification of patients (NRI -.029; 95% CI: -.215 to .130). Despite ABI being one of the independent predictors of hCVE, integration of ABI into the PCE model did not improve the efficacy of risk reclassification in patients with MRFs.

Vascular ageing: moving from bench towards bedside

Prevention of cardiovascular disease (CVD) remains one of the largest public health challenges of our time. Identifying individuals at increased cardiovascular risk at an asymptomatic, sub-clinical stage is of paramount importance for minimizing disease progression as well as the substantial health and economic burden associated with overt CVD. Vascular ageing (VA) involves the deterioration in vascular structure and function over time and ultimately leads to damage in the heart, brain, kidney, and other organs. Vascular ageing encompasses the cumulative effect of all cardiovascular risk factors on the arterial wall over the life course and thus may help identify those at elevated cardiovascular risk, early in disease development. Although the concept of VA is gaining interest clinically, it is seldom measured in routine clinical practice due to lack of consensus on how to characterize VA as physiological vs. pathological and various practical issues. In this state-of-the-art review and as a network of scientists, clinicians, engineers, and industry partners with expertise in VA, we address six questions related to VA in an attempt to increase knowledge among the broader medical community and move the routine measurement of VA a little closer from bench towards bedside.

Appraisal of Cardiovascular Risk Factors, Biomarkers, and Ocular Imaging in Cardiovascular Risk Prediction

Cardiovascular disease remains a leading cause of death worldwide despite the use of available cardiovascular disease risk prediction tools. Identification of high-risk individuals via risk stratification and screening at sub-clinical stages, which may be offered by ocular screening, is important to prevent major adverse cardiac events. Retinal microvasculature has been widely researched for potential application in both diabetes and cardiovascular disease risk prediction. However, the conjunctival microvasculature as a tool for cardiovascular disease risk prediction remains largely unexplored. The purpose of this review is to evaluate the current cardiovascular risk assessment methods, identifying gaps in the literature that imaging of the ocular microcirculation may have the potential to fill. This review also explores the themes of machine learning, risk scores, biomarkers, medical imaging, and clinical risk factors. Cardiovascular risk classification varies based on the population assessed, the risk factors included, and the assessment methods. A more tailored, standardised and feasible approach to cardiovascular risk prediction that utilises technological and medical imaging advances, which may be offered by ocular imaging, is required to support cardiovascular disease prevention strategies and clinical guidelines.

Ankle Brachial Index is a strong predictor of mortality in hypertensive patients: results of a five-year follow-up study

BACKGROUND

In the hypertensive population, the peripheral arterial disease (PAD) is considered one of the target organ damages. Ankle Brachial Index (ABI) measurement represents the widely accepted clinical method that may objectively detect the presence of PAD. The study aimed to assess how PAD revealed by ABI predicts mortality in patients with hypertension.

METHODS

In the follow-up time (5 years period) of the Hungarian ERV Study, a large scale, multicenter observational study, recruiting hypertensive subjects between 50-75 years, the association of PAD with the survival time was analysed. Several multivariate, interval-censored survival models were developed to assess this association.

RESULTS

Among the 21892 enrolled hypertensive patients, the prevalence of PAD (ABI≤0.9) was 14.4%. The crude death rate was 5.44% (1190 cases) over the available observational period. In multivariate models male sex, myocardial infarction in patients' history, diabetes, renal failure, PAD and cardiovascular risk (SCORE risk) were significantly associated with mortality. Lower ABI showed a continuous, close to linear association with worse survival. PAD was predictive for mortality risk in all SCORE patient groups.

CONCLUSIONS

Low ABI is a strong predictor of mortality in hypertensive patients between the age 50-75, even after adjustment for several potential confounders. The association is linear, with no apparent cut-off, suggesting that ABI should be handled as a continuous variable. The detection of PAD in hypertensives may contribute to the determination of total cardiovascular risk in hypertensive population.

Silent brain infarcts, peripheral vascular disease and the risk of cardiovascular events in patients with hypertension

BACKGROUND AND AIMS

We aimed to study the relationship between cerebral small vessel disease (cSVD) lesions, as markers of subclinical target organ damage (TOD) in the brain, and incident cardiovascular events (CVE).

METHODS

Data from the ISSYS (Investigating Silent Strokes in hYpertensives Study), which is a longitudinal and observational study conducted in patients with hypertension aged 50-70 years, and stroke-free at the inclusion. At the baseline visit, participants underwent a clinical interview, a brain MRI, urine and blood sampling collection and vascular testing studies. Therefore, we obtained markers of TOD from the brain [white matter hyperintensities, silent brain infarcts (SBI), cerebral microbleeds and enlarged perivascular spaces (EPVS)], from kidney (microalbuminuria, glomerular filtration) and regarding large vessels [ankle-to-brachial index (ABI), carotid-femoral pulse wave velocity]. Survival analyses were used to assess the relationship between these predictors and the incidence of cardiovascular events (CVE).

RESULTS

We followed-up 964 individuals within a median time of 5 years (4.7-5), representing 4377.1 persons-year. We found 73 patients presenting incident CVE, which corresponds to a rate of 8.2%. We found ABI less than 0.9 [hazard ratio, 2.2; 95% confidence interval (CI) 1.17-4.13, P value = 0.014] and SBI (hazard ratio, 2.9; 95% CI 1.47-5.58, P value = 0.002) independently associated with higher risk of incident CVE. The inclusion of both variables in a clinical model resulted in an increased discrimination of individuals with new CVE of 4.72%, according to the integrated discrimination index.

CONCLUSION

Assessment of SBI and ABI less than 0.9 may refine the cardiovascular risk stratification in patients with hypertension.

Long-Term Morbidity and Mortality after First and Recurrent Cardiovascular Events in the ARTPER Cohort

Background: Cardiovascular events are a major cause of mortality and morbidity worldwide. The risk of recurrence after a first cardiovascular event has been documented in the international literature, although not as extensively in a Mediterranean population-based cohort with low cardiovascular risk. There is also ample, albeit contradictory, research on the recurrence of stroke and myocardial infarctions (MI) after a first event and the factors associated with such recurrence, including the role of pathological Ankle-Brachial Index (ABI). Methods: The Peripheral Arterial ARTPER study is aimed at deepening our knowledge of patient evolution after a first cardiovascular event in a Mediterranean population with low cardiovascular risk treated at a primary care centre. We study overall recurrence, cardiac and cerebral recurrence. We studied participants in the ARTPER prospective observational cohort, excluding patients without cardiovascular events or with unconfirmed events and patients who presented arterial calcification at baseline or who died. In total, we analyzed 520 people with at least one cardiovascular event, focusing on the presence and type of recurrence, the risk factors associated with recurrence and the behavior of the ankle-brachial index (ABI) as a predictor of risk. Results: Between 2006 and 2017, 46% of patients with a first cardiovascular event experienced a recurrence of some type; most recurrences fell within the same category as the first event. The risk of recurrence after an MI was greater than after a stroke. In our study, recurrence increased with age, the presence of peripheral arterial disease (PAD), diabetes and the use of antiplatelets. Diabetes mellitus was associated with all types of recurrence. Additionally, patients with an ABI < 0.9 presented more recurrences than those with an ABI ≥ 0.9. Conclusions: In short, following a cardiac event, recurrence usually takes the form of another cardiac event. However, after having a stroke, the chance of having another stroke or having a cardiac event is similar. Lastly, ABI < 0.9 may be considered a predictor of recurrence risk.

Costs and effects of cardiovascular risk reclassification using the ankle-brachial index (ABI) in addition to the Framingham risk scoring in women

BACKGROUND AND AIMS

Ankle brachial index (ABI) is a simple and cheap parameter to assess the presence of atherosclerosis. It could also help correctly reclassify the cardiovascular risk when added to the Framingham risk score (FRS). Recent evidence has demonstrated improvement in prediction performance of ABI when added to FRS, particularly in women. However, no studies have been published yet evaluating the cost-effectiveness of this approach. This study attempts to fill in this gap by assessing the cost-effectiveness of ABI measurements in primary prevention in women.

METHODS

We developed a Markov model to compare two different strategies for assessing the cardiovascular risk (low, intermediate and high) among women in the general population: 1) FRS strategy, and 2) FRS + ABI strategy; and the relative impact associated with interventions for preventing CV events in intermediate and high-risk categories.

RESULTS

In the base-case analysis, FRS + ABI reported an additional cost of € 110 and a gain of 0.0039 QALYs per patient, resulting in an ICER of € 27.986/QALY, when compared to FRS alone. The ICER improved to €1.641/QALY when using a lifetime horizon. The effectiveness of preventive CV disease interventions reported also a significant impact. A 32% reduction of CV events was the minimum value estimated to maintain FRS + ABI as a cost-effective strategy.

CONCLUSIONS

The addition of ABI to FRS is a cost-effective approach in women classified at low and intermediate risk with FRS only. This new approach gives the possibility to reclassify and allocate them into the appropriate risk group and treatment.

[Prognostic importance of diagnosticated peripheral arterial disease through the ankle brachial index in spanish general population]

OBJECTIVE

The objectives have been to determine the prognostic value of having a low ankle-brachial index (ABI) for different cardiovascular diseases and whether it improves the predictive capacity of the main cardiovascular risk scores proposed for Spain.

DESIGN

Population-based cohort study LOCATION: A health area of the province of Badajoz (Spain) PARTICIPANTS: 2,833 subjects, representative of residents, between 25 and 79 years old, MEASUREMENTS: The ABI was measured at baseline and the first episode of ischemic heart disease or stroke, cardiovascular and total mortality, was recorded during 7 years of follow-up. The hazard ratio (HR) adjusted for cardiovascular risk factors and net reclassification index (NRI) by category, clinical and continuous for the risk functions REGICOR, FRESCO coronary heart disease, FRESCO cardiovascular disease and SCORE, were calculated.

RESULTS

2,665 subjects were analysed after excluding people with cardiovascular history and loss of follow-up. Low ABI was associated with adjusted HR (95% CI): 6.45 (3.00 - 13.86), 2.60 (1.15 - 5.91), 3.43 (1.39 - 8.44), 2.21 (1.27 - 3.86) for stroke, ischemic heart disease, cardiovascular mortality and total mortality respectively. The ABI improved the NRI (95% CI) in the intermediate risk category according to FRESCO cardiovascular equation by 24.1% (10.1 - 38.2).

CONCLUSIONS

Low ABI is associated with a significant increase in the risk of stroke, ischemic heart disease, cardiovascular mortality and total mortality in our population. The inclusion of ABI improved the reclassification of people at intermediate risk, according to FRESCO cardiovascular, so its use in that risk category would be justified.

Levels of ankle-brachial index and the risk of diabetes mellitus complications

OBJECTIVE

We sought to compare the association of categorized ankle-brachial index (ABI) with mortality and complications of diabetes in persons with no symptoms of peripheral arterial disease (PAD) and in primary cardiovascular disease prevention.

RESEARCH DESIGN AND METHODS

This is a retrospective cohort study of persons with type 2 diabetes aged 35-85 years, from 2006 to 2011. Data were obtained from the Sistema d'Informació per al Desenvolupament de la Investigació en Atenció Primària (SIDIAP^Q). Participants had an ABI measurement that was classified into six categories. For each category of ABI, we assessed the incidence of mortality; macrovascular complications of diabetes: acute myocardial infarction (AMI), ischemic stroke, and a composite of these two; and microvascular complications of this metabolic condition: nephropathy, retinopathy, and neuropathy. We also estimated the HRs for these outcomes by ABI category using Cox proportional hazards models.

RESULTS

Data from 34 689 persons with type 2 diabetes were included. The mean age was 66.2; 51.5% were men; and the median follow-up was 6.0 years. The outcome with the highest incidence was nephropathy, with 24.4 cases per 1000 person-years in the reference category of 1.1≤ABI≤1.3. The incidences in this category for mortality and AMI were 15.4 and 4.1, respectively. In the Cox models, low ABI was associated with increased risk and was significant from ABI lower than 0.9; below this level, the risk kept increasing steeply. High ABI (over 1.3) was also associated with significant increased risk for most outcomes.

CONCLUSIONS

The studied categories of ABI were associated with different risks of type 2 diabetes complications in persons asymptomatic for PAD, who were in primary cardiovascular prevention. These findings could be useful to optimize preventive interventions according to the ABI category in this population.

Reclassification of the Framingham risk score and its agreement with other three calculations

Objective: To investigate the concordance between the modified Framingham score using the ankle-brachial index and the high-sensitivity C-reactive protein with the other scores. Materials and method: Cross-sectional study nested with a cohort, with elderly population, from January to March, 2018. The population characterization was presented as mean, median, absolute and relative frequencies according to degree of normality. The Kappa concordance of the modified Framingham score was calculated with the Framingham score itself, with the Systematic Coronary Risk Evaluation (Score) and with the Prospective Cardiovascular Munster (Procam). Results: The modified Framingham score shows moderate Kappa concordance with the Framingham score and the Score (p < 0.001), but weak with Procam. The ultra-sensitive C-reactive protein presented more reclassification of individuals among risk strata than the ankle-brachial index. Conclusions: The Framingham score modified with the Framingham score itself, and then with the Score obtained a higher proportion of concordant cases in the high-risk stratum. High-sensitivity C-reactive protein and the ankle-brachial index modify cardiovascular risk as emerging factors to provide an accurate risk stratification and to infer better management of the therapy. Thus, the Framingham score with its reclassification is the best screening tool for cardiovascular risk.

Oscillometric and Doppler Ankle Brachial Indexes as predictors of all-cause mortality in a Primary Care population

BACKGROUND

Doppler Ankle Brachial Index (ABI), the non-invasive reference standard for peripheral arterial disease (PAD) in Primary Care, has proved good capacity to predict all-cause mortality. However, the role of oscillometric ABI is uncertain. This study aims to evaluate the ability of oscillometric and Doppler ABI to predict all-cause mortality in a Primary Care population.

METHODS

Oscillometric and Doppler ABI were measured in 203 consecutive subjects with ≥1 cardiovascular risk factors or intermittent claudication. Pathologic ABI was defined when ABI was ≤0.9 or ≥1.4, and when the oscillometer was unable to record a value (oscillometric error). All-cause mortality was ascertained through examination of electronic medical records or telephone contact.

RESULTS

After analyzing 602.9 subjects/year, all-cause mortality was recorded in 17 (8.4%) patients. Kaplan-Meier survival curves for oscillometric (Log-Rank test χ2=66.02, P<0.001) and Doppler ABI (Log-Rank test χ2=42.30, P<0.001) showed that a pathologic ABI is associated with all-cause mortality. After adjusting for covariates, the hazard ratio in multivariable Cox regression were 4.52 (95% CI: 1.67-12.18, P=0.003) and 2.08 (95% CI: 0.83-5.18, P=0.117) for oscillometric and Doppler ABI models, respectively. When introducing oscillometric and Doppler ABI simultaneously in the Cox regression model, only oscillometric ABI was an independent predictor with a hazard ratio=7.90 (95% CI: 1.79-34.83, P=0.006). Regarding Doppler ABI, no significant differences were found in all-cause mortality between low ABI (≤0.9) and calcified ABI (≥1.4), (Log-Rank test χ2=0.98, P=0.322).

CONCLUSIONS

Oscillometric ABI predicted all-cause mortality in a Primary Care population even better than Doppler ABI, irrespective of cardiovascular risk factors. Oscillometric ABI, due to a high feasibility, could routinely identify high-risk patients to implement preventive measures.

Low, borderline and normal ankle-brachial index as a predictor of incidents outcomes in the Mediterranean based-population ARTPER cohort after 9 years follow-up

BACKGROUND

Guidelines recommended adopting the same cardiovascular risk modification strategies used for coronary disease in case of low Ankle-brachial index (ABI), but here exist few studies on long-term cardiovascular outcomes in patients with borderline ABI and even fewer on the general population.

AIM

The aim of the present study was to analyze the relationship between long-term cardiovascular events and low, borderline and normal ABI after a 9-year follow up of a Mediterranean population with low cardiovascular risk.

DESIGN AND SETTING

A population-based prospective cohort study was performed in the province of Barcelona, Spain.

METHOD

A total of 3,786 subjects >49 years were recruited from 2006-2008. Baseline ABI was 1.08 ± 0.16. Subjects were followed from the time of enrollment to the end of follow-up in 2016 via phone calls every 6 months, systematic reviews of primary-care and hospital medical records and analysis of the SIDIAP (Information System for Primary Care Research) database to confirm the possible appearance of cardiovascular events.

RESULTS

3146 individuals participated in the study. 2,420 (77%) subjects had normal ABI, 524 (17%) had borderline ABI, and 202 (6.4%) had low ABI. In comparison with normal and borderline subjects, patients with lower ABI had more comorbidities, such as hypertension, hypercholesterolemia and diabetes. Cumulative MACE incidence at 9 years was 20% in patients with low ABI, 6% in borderline ABI and 5% in normal ABI. The annual MACE incidence after 9 years follow-up was significantly higher in people with low ABI (26.9/1000py) (p<0.001) than in borderline (6.6/1000py) and in normal ABI (5.6/1000py). Subjects with borderline ABI are at significantly higher risk for coronary disease (HR: 1.58; 95% CI: 1.02-2, 43; p = 0,040) compared to subjects with normal ABI, after adjustment.

CONCLUSION

The results of the present study support that low ABI was independently associated with higher incidence of MACE, ICE, cardiovascular and no cardiovascular mortality; while borderline ABI had significantly moderate risk for coronary disease than normal ABI.

Correction: Contribution of the ankle-brachial index to improve the prediction of coronary risk: The ARTPER cohort

[This corrects the article DOI: 10.1371/journal.pone.0191283.].