Atrial Fibrillation Registry for Ankle-brachial Index Prevalence Assessment: Collaborative Italian Study.

Atrial fibrillation (AF) is the most common sustained dysrhythmia encountered in clinical practice in North America and Europe, accounting for approximately one-third of all hospitalizations for a cardiac rhythm abnormality. The presence of AF markedly increases the patient's risk for developing arterial embolism and stroke, depending on the presence of other clinical conditions, such as hypertension and diabetes. AF is associated with a fivefold increased risk for stroke, and is estimated to cause 15% of all strokes.

Patients with AF frequently have several risk factors for atherosclerosis, including hypertension, diabetes, and dyslipidemia. Accordingly, systemic signs of atherosclerosis can be detected in AF patients, and these likely accounts for an enhanced risk of coronary heart disease. In addition to cerebrovascular disease, patients with AF may suffer from coronary events including myocardial infarction (MI), but the rate of MI in AF patients seems to be variable, but often underestimated.

Moreover, coexistence of peripheral arterial disease (PAD) is a relevant clinical sign of systemic atherosclerosis.

Ankle-brachial index (ABI) is a simple, inexpensive, and non-invasive PAD measurement, even at the pre-symptomatic phase when intervention can improve prognosis and prevent or delay severe complications ABI is calculated by measuring the systolic blood pressure in the posterior tibial and/or the dorsalis pedis arteries either in both legs or 1 leg chosen at random (using a Doppler probe or alternative pulse sensor), with the lowest ankle pressure then divided by the brachial systolic blood pressure. In addition to peripheral artery disease, the ABI also is an indicator of generalized atherosclerosis because lower levels have been associated with higher rates of concomitant coronary and cerebrovascular disease, and with the presence of cardiovascular risk factors.

Two large studies in patients with AF document the existence of PAD in about 3-5% of patients. It is possible, however, that such an incidence has been underestimated as only symptomatic patients were considered as affected by PAD. As PAD is an important marker of systemic atherosclerosis, its association with AF reinforces the concept that patients with AF have systemic atherosclerosis that potentially account for coronary complications.

To date, a national registry of AF patients is not available to verify the real impact of cardiovascular events in this clinical setting.

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Key information

Conditions

Atrial Fibrillation Arrhythmias, Cardiac Cardiovascular Diseases Heart Diseases Pathologic Processes Pathological Conditions, Signs and Symptoms Peripheral Vascular Disease Peripheral Vascular Diseases Vascular Diseases

Age range

18 year–90 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Sapienza - University of Rome and SIMI, Rome, Italy

About this study

Study design: Prospective longitudinal study

Methods and Materials: The investigators planned to assess at baseline and at scheduled follow up visits :

Ankle-Brachial Index measurement
Anamnestic clinical information and Anthropometric measurements
Echocardiogram (volume size), electrocardiogram (AF type)
Outcome events such as nonfatal or fatal acute myocardial infarction, target lesion or vessel revascularization nonfatal or fatal ischemic stroke, transient ischemic attack, death from any cardiac or vascular cause, death from any cause Study duration: 3 years follow-up Statistical methods: The prevalence will be calculated by exact confidence intervals (Wilson method). The cumulative incidence will be calculated by the product-limit estimator of Kaplan-Meyer and presented with confidence intervals at 95%. The incidences and prevalences will be then adjusted through appropriate multivariate analysis (using the Cox proportional hazards model and logistic model) that will take into account the effect of potential confounders. Similarly, the effect-center presence will be checked and possibly removed. Secondary endpoints will be assessed by using Log-rank test method, and by the Cox model (with time-dependent effects) multivariate analysis.

Subgroups analysis will be also conducted for patients with first onset of AF or recurrent AF Sample size: The investigators plan to include in the study n = 3,000 AF patients, with competitive recruitment between centers involved in the study. The sample size was calculated assuming an expected prevalence of 19% at time zero, and in order to obtain a confidence interval 95% to prevail at time zero whose distance from the edge is less than or equal to 1.4%. This sample size yields a power greater than 99.9% for the secondary endpoint, assuming an event rate of 19% for patients with ABI <=0.9, and 10% for patients with ABI >0.9.An interim analysis showed an ABI prevalence, calculated by exact confidence intervals, of 21% in patients with AF, it is considered to interrupt the enrollment, as the observed prevalence is greater than two percentage points higher than that assumed. The sample size is amended as follows: a sample of 2027 patients leads to the expected prevalence of 21% with a confidence interval width of 3.5. This sample size has no impact on the power of the secondary objective.

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Non-valvular atrial fibrillation (paroxysmal, persistent or permanent)
Genders Eligible for Study: Both
Ages Eligible for Study 18 years and older
Signed written informed consent

Exclusion criteria

Valvular AF
Cancer
Disease with life expectancy less than 3 years
Pregnancy
Hyperthyroidism

Treatment and study plan

Primary outcomes

ABI PREVALENCE

Time frame: 1 year

To estimate peripheral artery disease prevalence (defined by an Ankle-brachial index <=0.9) in AF patients.

Secondary outcomes

Vascular Events

Time frame: 3 years

To Estimate ischemic cardiovascular and cerebro-vascular events (fatal or non-fatal ) incidence in AF patients with or without peripheral artery disease

Sponsors and collaborators

Lead sponsor

University of Roma La Sapienza

Other

Registry information

Acronym: ARAPACIS

Important dates

Study start: 2010
Primary completion: 2012
Study completion: 2014
First posted: Jul 13, 2010
Registry last updated: Mar 9, 2016

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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