Interpretation of Doppler segmental pressures in peripheral vascular occlusive disease

Peripheral arterial disease symptom subtype and walking impairment

Walking impairment is common in patients with peripheral arterial disease (PAD). The purpose of this study was to compare specific leg symptoms and walking impairment in a racially diverse cohort of patients with PAD. Patients who were receiving care at the Michael E DeBakey Veterans Affairs Medical Center or in the Harris County Hospital District were screened for PAD, which was diagnosed in the office setting by blood pressure measurements that were used to calculate the ankle-brachial index (a level <0.90 was defined as disease). To define leg symptoms, we asked patients to complete the San Diego Claudication Questionnaire. Based on the questionnaire results, leg symptoms were categorized as: asymptomatic, atypical, and intermittent claudication. The patients also completed the Walking Impairment Questionnaire. Among 403 patients screened (136 Caucasians, 136 African Americans and 131 Latinos), 67 were found to have PAD (18 Caucasians, 31 African Americans and 18 Latinos). The mean age of the cohort was 63.8 years (standard deviation (SD) 7.3). Walking distance, speed and stair climbing scores were lower (p < 0.0001) for patients with PAD and leg pain on exertion or at rest when compared with patients with PAD without leg symptoms or with symptoms of intermittent claudication. For patients with PAD and leg pain on exertion and at rest, the walking distance score was 27.1 ± SD 37.7 compared with 41.0 ± 38.4 for those with asymptomatic disease who were inactive, and with 38.5 ± 42.7 for those with intermittent claudication ( p = 0.02).

In an ethnically diverse primary care clinic population, patients with PAD and leg pain on exertion and at rest had greater compromise in their walking ability when compared with patients with intermittent claudication. The reasons for the significant impairment in walking among patients with PAD and these atypical leg symptoms may stem from coexisting illnesses or other as yet undefined factors. Future research should focus on methods to improve daily walking in patients with PAD and atypical leg symptoms.

Photoplethysmography and continuous-wave Doppler ultrasound as a complementary test to ankle-brachial index in detection of stenotic peripheral arterial disease

PURPOSE

We evaluated the sensitivity and specificity of ankle-brachial index (ABI), photoplethysmography (PPG), and continuous-wave Doppler ultrasound (CWD) in the detection of anatomically stenotic peripheral arterial disease (PAD).

METHODS

Ninety-seven patients (194 legs) patients who had coincidentally undergone computed tomography angiography (CTA), ABI, PPG, and CWD for the evaluation of PAD were retrospectively reviewed. Sensitivity and specificity were measured.

RESULTS

Among 194 legs, 163 (84%) legs had stenotic PAD on CTA. Overall sensitivity of ABI, PPG, and CWD was 69.3%, 81.6%, and 90.8% and specificity was 96.8%, 77.4%, and 64.5%, respectively. Ankle-brachial index showed a statistically significantly decreased sensitivity (14.8%) for below trifurcation level stenosis compared with CWD (92%) and PPG (67%). The sensitivity of ABI was also significantly decreased in single level and moderate stenosis (45.1% and 42.1%, respectively). In contrast, the sensitivity of CWD and PPG was not significantly decreased.

CONCLUSION

The ABI showed significantly decreased sensitivity especially in stenosis below the trifurcation level. Both PPG and CWD were complementary to ABI in these groups of patients.

Ethnicity and peripheral arterial disease

OBJECTIVE

To determine whether race/ethnicity is an independent risk factor for peripheral arterial disease (PAD).

PATIENTS AND METHODS

From September 2000 through August 2001, we screened patients (age > or = 55 years) for PAD within 4 primary care clinics located in the Houston, Tex, area. Variables that were bivariately associated with PAD (P< or = .05) were selected for entry into a multivariate logistic regression model to determine the independent risk factors for PAD.

RESULTS

Among 403 patients (136 white, 136 African American, and 131 Latino patients, 81 of whom were Spanish speaking), the prevalence of PAD was 22.8% among African American patients, 13.7% among Latino patients, and 13.2% among white patients (P = .06). Within the multivariate model, adjusting for age, smoking status (odds ratio [OR], 2.58; 95% confidence interval [CI], 1.27-5.25), diabetes mellitus (OR, 2.98; 95% CI, 1.58-5.63), hypertension (OR, 2.58; 95% CI, 1.12-5.95), and education, African American and Latino patients were not more likely than white patients to have a diagnosis of PAD (OR 1.89, 95% CI 0.89-3.99 and OR 1.54, 95% CI 0.59-4.06, respectively).

CONCLUSION

After adjusting for atherosclerotic risk factors and level of education, ethnicity was not an independent risk factor for PAD. When determining ethnic variation in outcomes among patients with PAD, efforts are needed to better understand the role of the primary care setting to reduce the burden of social inequality on health.

Process of care and outcomes in peripheral arterial disease

Peripheral arterial disease (PAD) is a prevalent illness that most commonly affects patients older than 60 years. As the population ages, the prevalence of PAD and its associated adverse outcomes will also increase. Adverse outcomes in PAD are either systemic (ie, cardiovascular events such as myocardial infarctions or strokes) or localized to the legs (ie, bypass surgery or amputation). Although much research has focused on adverse systemic outcomes in patients with PAD, less is known about those factors related to adverse limb events. The Centers for Disease Control and Prevention estimate that more than 100,000 amputations are performed in the United States each year. What remains to be determined is the association between how physicians manage patients with PAD (ie, process of care) and the development of adverse limb outcomes. Determining the association of the management of PAD with adverse limb outcomes will highlight those areas in which to focus to improve the quality of care for patients with this disease. Understanding the relationship between risk factors, process of care, and outcomes will be of importance to patients, clinicians, and policy makers. The purpose of this article is to review the burden of PAD and to discuss the association of process of care with adverse limb outcomes in patients with PAD.

An alteration in arterial compliance associated with elevated aerobic fitness

OBJECTIVE

To identify a nonpharmacologic method of enhancing arterial compliance, a correlate of atherogenesis; to determine the relationship between aerobic fitness levels and arterial compliance; and to identify a characteristic Doppler analog waveform associated with elevated levels of aerobic fitness.

DESIGN

A cross-sectional design was used to compare the Doppler studies of sedentary subjects and aerobically trained subjects. The trained subjects were divided into a moderately trained group and a highly trained group.

SETTING AND PARTICIPANTS

One hundred subjects consisting of 50 sedentary control subjects and 50 aerobically trained subjects in a university-based setting. The mean age of the total group of subjects was 36.0+/-8.6 years. Each group had an equal number of male and female subjects. Control subjects were sedentary, with normal vascular risk factor profiles and a mean aerobic capacity (maximum oxygen consumption) of 25.8+/-3.0 mL x kg(-1) x min(-1). Trained subjects were divided into a moderately trained group and a highly trained group. The mean aerobic capacity for the moderately trained group was 46.0+/-4.4 mL x kg(-1) x min(-1), and that for the highly trained group was 63.3+/-6.7 mL x kg(-1) x min(-1). A standard Doppler examination, including ankle pressure index was performed on each subject.

MAIN OUTCOME MEASURE

Arterial compliance measurements were recorded by using A-mode Doppler ultrasonography and analyzed by diastolic flow analysis.

RESULTS

Control subjects had a mean arterial compliance level of 21.1%+/-2.5%. The moderately trained subjects had a mean compliance level of 34.8%+/-4.9%, and the highly trained subjects had a mean compliance level of 46.0%+/-6.7%. An analysis of variance was used for this comparison and was significant at a P value of less than .01.

CONCLUSION

These results demonstrate that elevated aerobic fitness levels are associated with an augmentation in arterial compliance. A linear relationship existed in our data between aerobic fitness levels and arterial compliance. This study suggests that enhanced arterial compliance is another beneficial cardioprotective effect associated with aerobic training.

A comprehensive review of vascular ultrasound for intensivists

Ultrasound has an increasingly important role in evaluation of the vascular system. Ultrasound is especially useful for intensive care patients because of the frequency of vascular complications developing in the ICU setting, as well as the ability of ultrasound to be performed at the patient's bedside. Ultrasound is the method of choice for evaluation of deep vein thromboembolic disease of the lower extremity in all patients; it demonstrates excellent sensitivity and specificity for this condition. It should also be the initial method of evaluation of upper extremity deep vein thrombosis. However, ultrasound may be limited in this assessment due to lack of reliably demonstrating the central subclavian and innominate veins, and therefore may be inadequate for evaluation of malfunctioning central venous catheters. Ultrasound can reliably identify and potentially be used to treat arterial complications of arterial catheterization, such as pseudoaneurysms. Similarly, ultrasound is accurate in the diagnosis of the presence of abdominal aortic aneurysm, and ultrasound can be used to assess carotid and lower extremity arteries noninvasively. Finally, ultrasound is useful for evaluation of hemodialysis fistulas and vascular complications of transplants.

Lower limb colour flow imaging: a comparison with ankle: brachial measurements and angiography

Peripheral lower limb vascular disease represents a substantial health problem. Arteriography is currently the 'gold standard' imaging modality. However, much effort is presently being channeled towards alternative non-invasive techniques. To date, this involves mainly the interpretation of ankle: brachial pressure indices and segmental pressure measurements. A prospective pilot study of 20 patients (40 limbs) comparing these two techniques with colour Doppler ultrasound was carried out. Although ankle: brachial indices could accurately predict disease (sensitivity 100%, accuracy 92.5%), it failed to localize it; neither a high thigh: brachial index nor segmental drop could localize disease to the iliac (accuracy 70%) or femoro-popliteal (accuracy 55%) vessels respectively. Colour Doppler ultrasound correctly differentiated iliac from femoro-popliteal disease. It had an overall diagnostic accuracy of 90% in the femoral and popliteal vessels for both occlusion and stenosis and diagnosed 10 of 11 iliac lesions. Colour Doppler ultrasound has many advantages over pressure measurements in that it can both diagnose and localize arterial lesions accurately. We feel that using both techniques prior to angiography can accurately separate patients into either a surgical or angioplasty group. This may help utilize angiographic resources and radiologists' time more efficiently as well as reducing radiation dose to both patients and staff.

Accuracy of color Doppler flow mapping for evaluation of the severity of femoropopliteal arterial disease: a prospective study

The usefulness of color Doppler flow mapping for estimating the severity of femoropopliteal lesions was compared with that of angiography in 35 patients (70 extremities). Sonography depicted significant (greater than 40% luminal narrowing) arterial lesions in 45 of 47 lower extremities in which such lesions were present (sensitivity, 0.96 [95% confidence limits; 0.86, 0.99]). The absence of significant segmental stenosis or occlusion was confirmed in 15 of the 23 normal extremities (specificity, 0.65 [0.45, 0.81]). Occlusions amenable to bypass surgery were correctly predicted in 25 of 26 (sensitivity, 0.96 [0.81, 0.99]) and were excluded in 41 of 44 extremities (specificity, 0.93 [0.82, 0.98]). Lesions amenable to angioplasty were detected in 16 of 21 instances, with overestimation of severity in three lesions that were judged suitable for bypass surgery; two lesions were missed. Preangiographic screening with color Doppler flow mapping is an accurate method for predicting the presence of femoropopliteal artery occlusions amenable to bypass surgery. It is also a sensitive method for predicting the presence of peripheral arterial disease.

Noninvasive assessment of lower extremity arterial disease

Although angiography is the accepted "gold standard" for demonstrating the presence of arterial occlusive disease, it is less accurate for grading the associated hemodynamic consequences and is prohibitively invasive and expensive to be used as a first-line investigation. Currently available noninvasive tests allow not only for the detection of perfusion abnormalities, but for an appreciation of their severity as well as their likely location. This information is invaluable for predicting the need for revascularization, guiding the choice of reconstructive procedure, and predicting the likelihood of healing of amputation wounds and ischemic lesions. Although some obstructive lesions are easily detected, others require more in-depth testing to reveal and quantify. Consequently, a thorough understanding of available noninvasive diagnostic modalities, including both their capabilities as well as their pitfalls, is paramount to the effective practice of vascular surgery.

Vascular laboratory prediction of pedal pressure following femoropopliteal bypass

This study examines the hypothesis that postoperative ankle-brachial pressure index (postop ABI) can be accurately predicted using noninvasive preoperative segmental leg pressure measurements. Seventy-three patients who underwent successful reverse autogenous vein femoropopliteal bypass and who had pre- and postoperative segmental leg pressure measurements were examined. Predicted postop ABI was estimated using the following formula: Postop ABI = 1 + (Preop ABI) - (Preop BKI). (BKI = below-knee brachial pressure index). Using this formula, 56 out of 73 (81%) patients had a measured postop ABI +/- 20% of predicted postop ABI. Five out of 73 (7%) patients had postop ABI less than 80% predicted, while 12 out of 73 (16%) patients had postop ABI greater than 120% of predicted. All patients with postop ABI greater than 120% of predicted had apparent tibial artery occlusive disease as indicated by preoperative gradients (BKI-ABI) greater than 0.15.