The value of routine screening for peripheral arterial disease in stable outpatients with a history of coronary artery or cerebrovascular disease

BACKGROUND

Frequently unrecognised, PAD is associated with reduced quality of life and an increased mortality rate because of a greater propensity for fatal ischaemic events. PAD commonly coexists with coronary and cerebrovascular disease and is associated with poorer outcomes in such patients. The Edinburgh Claudication Questionnaire (ECQ) and the ankle-brachial index (ABI) are screening methods to identify the presence of PAD. This study used these methods to estimate the rate of previously undiagnosed PAD and to validate the ECQ against ABI in a Canadian outpatient population with manifest cerebrovascular or coronary disease.

METHODS

At a regular office visit, patients completed the ECQ and were categorised as ECQ(+) or ECQ(-). All ECQ(+) and a randomly selected 25% of ECQ(-) patients were referred for ABI measurement. An ABI < 0.9 was considered positive. The prevalence of PAD in the patient population and the sensitivity and specificity of the ECQ score against the ABI were assessed.

RESULTS

Of 2235 patients enrolled, 815 were selected for an ABI [ECQ(-), n = 478; ECQ(+), n = 337]. Extrapolated PAD prevalence in the total population was 12.3% (highest arterial pressure [HAP] method) and 20.8% (lowest arterial pressure [LAP] method), with a significantly higher prevalence found in diabetic patients than non-diabetic patients (p < 0.0001). Because ECQ is only a measure of symptomatic disease, it had poor sensitivity (35.3% and 25.8%), but high specificity (88.2% and 88.3%) using the HAP and LAP methods of ABI measurement, respectively.

CONCLUSIONS

Undiagnosed PAD is common in stable outpatients with a prior history of manifest cardiovascular disease, particularly in those with diabetes. The ECQ does not possess the diagnostic value of the ABI in detecting PAD in this high-risk population, but may be useful to raise suspicion of PAD to be confirmed by ABI assessment.

Evaluation of the consequences associated with diffuse vascular disease history in patients diagnosed with peripheral arterial disease: estimates from Saskatchewan health data

Background

Peripheral arterial disease (PAD) is caused by narrowing of the arteries in the lower extremities. Limited data exist concerning the impact of diffuse vascular disease (DVD) on prognosis and costs. Thus, the objective of this study is to estimate the impact of DVD on morbidity, mortality and costs.

Methods

PAD was identified between 1985 and 1995 and classified by extent of DVD at diagnosis: none (PAD only, reference group), prior myocardial infarction (MI), prior stroke, prior MI and stroke (MI + stroke), prior transient ischemic attack (TIA). Deaths and hospitalizations were identified through December 2000. Hospitalization costs were estimated from the Ontario Case Cost Project, reported in 2002 $CAD. Proportional hazards analyses measured the impact of vascular involvement on mortality while controlling for risk factors (e.g., age, cardiovascular history).

Results

Overall, 16,439 patients with PAD were included; 14.8% had a prior MI, 10.2% a prior stroke, 2.6% prior MI + stroke, 6.4% prior TIA, two-thirds had PAD only. Median survival was shorter for patients with prior MI (9.3 yrs), TIA (6.3), stroke (4.7), and MI+stroke (4.1) versus the reference group (9.9, p < 0.05, all comparisons). Analyses revealed that the death risk was 60% higher in patients with prior stroke and 84% higher for MI + stroke. Atherothrombotic and bleeding event-related costs were $712, $337, $268, and $170 higher per patient/year of follow-up in patients with a history of MI+stroke, MI, stroke, and TIA, respectively.

Conclusion

Patients diagnosed with PAD with DVD have higher risk of poor outcomes and increased costs.