Reliability of common femoral artery hemodynamics in assessing the severity of aortoiliac inflow disease

Can Common Femoral Artery Doppler Waveform Analysis Reliably Predict Hemodynamically Significant Disease of the Aortoiliac Arteries? A Systematic Review and Meta-Analysis

BACKGROUND

Many guidelines recommend duplex scanning as the first-line investigation for peripheral arterial disease. Qualitative evaluation of the common femoral artery (CFA) waveform provides information regarding the likely presence of significant aortoiliac disease. Certain centers use a "triphasic-and-down" policy, proceeding directly to antegrade endovascular intervention of infra-inguinal disease if the CFA waveform is triphasic. Others mandate cross-sectional imaging regardless of CFA waveform to exclude occult aortoiliac disease. This review aims to analyze the reliability of CFA waveform in excluding significant aortoiliac disease.

METHODS

MEDLINE, Embase, Cochrane library, and reference lists were searched for studies comparing CFA waveform analysis with reference tests assessing aortoiliac disease. Triphasic waveforms were considered "normal", while biphasic/monophasic were considered "abnormal." Meta-analyses using a bivariate model produced pooled diagnostic accuracy metrics, including negative and positive predictive values, sensitivity, and specificity.

RESULTS

Eight studies with 1,139 limbs were included. Where reported, the mean age was 67, 64.4% had claudication and 35.6% had critical limb ischemia, 42.3% were smokers, and 33.3% were diabetic. Reference investigations were catheter or cross-sectional angiography(n = 5), aortoiliac duplex(n = 2), and intra-arterial pressures(n = 1). The pooled negative predictive value was 84.7% (95% confidence interval [CI]: 59.3%-97.0%), meaning a triphasic waveform correctly excludes significant aortoiliac disease 84.7% of the time, and positive predictive value was 71.3% (95% CI: 36.1%-93.1%). Sensitivity was 0.86 (95% CI: 0.78-0.92), indicating 14% of patients with significant aortoiliac disease had triphasic waveforms, and specificity was 0.78 (95% CI: 0.61-0.89).

CONCLUSION

The best data available suggests Doppler waveform analysis lacks precision in identifying and excluding significant aortoiliac disease compared to heterogenous reference tests. A low threshold for cross-sectional imaging before antegrade endovascular intervention may be appropriate.

Intravascular Ultrasound during Endovascular Intervention for Peripheral Artery Disease, by Severity, Location, Device, and Procedure

There is limited evidence for the role of intravascular ultrasound (IVUS) in patients who underwent peripheral vascular intervention (PVI). We conducted retrospective cohort study utilizing the Healthcare Cost and Utilization Project-Agency for Healthcare Research and Quality National Readmission database to delineate outcomes in IVUS-guided PVI versus non-IVUS-guided PVI. The present study utilized National Readmission database between January 1, 2016, and December 31, 2019. We identified patients who underwent endovascular intervention for peripheral artery disease using relevant International Classification of Diseases, Tenth Revision, Procedural Coding System. The cohort was divided based on the use of IVUS during the procedure. The primary outcome was major amputation at 6 months after index hospitalization. Measured confounders were matched using propensity score inverse probability of treatment weighing method. We further performed a subgroup analysis based on disease severity, location of intervention, device, and procedure. A total of 434,901 hospitalizations were included in the present analysis. PVI with IVUS compared with no IVUS had similar risk of amputation at 6 months (195 of 8,939 [2.17%] vs 10,404 of 384,003 [2.71%]), hazard ratio 0.98, CI 0.77 to 1.25. Further, there was no difference in the rates of secondary outcomes. On subgroup analysis, amputation rates were significantly lower in patients with rest pain, in iliac intervention, or patients who underwent drug-eluting stent implantation with the use of IVUS compared with no IVUS. This nationwide observational study showed that there was no difference in major amputation rates with the use of IVUS in patients who underwent PVI. However, in subgroup of patients with rest pain, iliac intervention or drug-eluting stent implantation IVUS use was associated with significantly lower major amputation rates.

The Impact of Diabetes in Intermittent Claudication: A Prospective Cohort Study

The aim of this study was to determine the lower-limb outcome in patients with intermittent claudication (IC) and to identify predictors for deterioration. This study employed a prospective observational cohort single-centre design. One hundred fifty patients with IC attending a vascular surgery unit for the first time were recruited. Lower limb perfusion was assessed utilising ankle brachial index (ABI) measures, toe-brachial index (TBI) measures, Doppler waveform analysis and the walking impairment questionnaire. Follow-up was conducted after 1 year and 2 years following recruitment to assess haemodynamic parameters, symptom severity and outcome. Recruited participants had a mean age of 69.7 (±9.3) years, BMI 27.8(±4.2) and 79.3% were men. Significant haemodynamic decline (decline in ABPI by ≥0.15 and/or decline in TBPI by ≥0.1) occurred in 50.6% of the cohort within 2 years of whom 23.3% developed chronic limb threatening ischaemia (CLTI) with rest pain and/or tissue loss. Baseline ABPI, ABPI ≤ 0.5, TBPI ≤ 0.39, infrapopliteal artery (IPA) disease and high Haemoglobin A1c were identified as significant predictors for deterioration to CLI. (P < .05, binomial logistic regression). Patients with IC are at a high risk of developing CLTI within 2 years. Risk of lower limb adverse events is tripled in patients with IPA disease, low ankle and toe pressures and poorly controlled diabetes. Early identification of those at high risk for early deterioration may justify a paradigm shift in the management of this subgroup.

Duplex ultrasound derived maximal systolic acceleration can be a reliable and rapid alternative to ankle brachial pressure indices for the diabetic population with lower extremity arterial disease; a prospective, observational cohort study

Objectives: Ankle brachial pressure index (ABPI) is limited for diabetic patients. This can have costly impacts upon patient's quality of life along with healthcare budgets, with diabetic care equating to approximately 10% of NHS expenditure.¹¹ We aimed to determine whether ultrasound waveform parameters are an alternative for quantifying lower extremity peripheral arterial disease (PAD) where ABPI is unreliable. Design: This was a prospective, observational study. Waveform parameters, systolic rise time (SRT), maximal systolic acceleration (AccMax) and peak systolic velocity (PSV) were recorded at ankle and compared to the ABPI and an aorta-ankle duplex ultrasound scan (DUS) as gold standard. Setting: Measurements were obtained by a Clinical Vascular Scientist at the Royal Free Hospital. Participants: Participants (≥18yrs) with known PAD, but without previous vascular intervention were allocated to non-diabetic control (n = 24) and diabetic test groups (n = 22). Outcome measures: The primary outcome measure was the correlation of novel ultrasound derived indices to PAD severity. The secondary outcome was the efficacy of this correlation in the diabetic population. Results: AccMax was most powerful in detecting PAD in both groups when compared to ABPI in the controls (r = 0.805; p < 0.01) and to DUS in control and test groups (r = −0.633 to −0.643; p < 0.01). In the test group, PSV did not consistently quantify PAD. SRT measurements were inconclusive throughout. Conclusion: AccMax is a rapid alternative tool for diagnosing PAD in diabetic patients. With further research, this simple test may prove useful for monitoring PAD progression in patients unsuitable for ABPI, reducing the need for lengthy repeat duplex scans.

Sex- and Age-Related Physiological Profiles for Brachial, Vertebral, Carotid, and Femoral Arteries Blood Flow Velocity Parameters During Growth and Aging (4-76 Years): Comparison With Clinical Cut-Off Levels

Ultrasound-derived blood flow velocity (BFV) levels [e.g., peak systolic velocity (PSV)], intrabeat indexes (e.g., resistive), and intersegment ratios [e.g., internal/common carotid artery (ICA/CCA) PSV ratio] are assessed to describe cardiovascular physiology and health status (e.g., disease severity evaluation and/or risk stratification). In this respect, fixed cut-off values (disregard of age or sex) have been proposed to define “significant” vascular disease from BFV-derived data (parameters). However, the use of single fixed cut-off values has limitations. Accurate use of BFV-derived parameters requires knowing their physiological age-related profiles and the expected values for a specific subject. To our knowledge, there are no studies that have characterized BFV profiles in large populations taking into account: (i) data from different age-stages (as a continuous) and transitions (childhood–adolescence–adulthood), (ii) complementary parameters, (iii) data from different arteries, and (iv) potential sex- and hemibody-related differences. Furthermore, (v) there is little information regarding normative data [reference intervals (RIs)] for BFV indexes.

Aims: The aims of this study are the following: (a) to determine the need for age-, body side-, and sex-specific profiles for BFV levels and derived parameters (intrabeat indexes and intersegment ratios), and (b) to define RIs for BFV levels and parameters, obtained from CCA, ICA, external carotid, vertebral, femoral, and brachial arteries records.

Methods: A total of 3,619 subjects (3–90 years) were included; 1,152 were healthy (without cardiovascular disease and atheroma plaques) and non-exposed to cardiovascular risk factors. BFV data were acquired. The agreement between left and right data was analyzed (Concordance correlation, Bland–Altman). Mean and SD equations and age-related profiles were obtained for BFV levels and parameters (regression methods; fractional polynomials).

Results: Left and right body-side derived data were not always equivalent. The need for sex-specific RIs was dependent on the parameter and/or age considered. RIs were defined for each studied artery and parameter. Percentile curves were compared with recommended fixed cut-off points. The equations for sex, body-side, and age-specific BFV physiological profiles obtained in the large population (of children, adolescents, and adults) studied were included (spreadsheet formats), enabling to determine for a particular subject, the expected values and potential data deviations.

Duplex Ultrasound as a reliable alternative to CT angiography for treatment planning of Peripheral Artery Disease

BACKGROUND

The aim of this work is to compare the diagnostic accuracy of Duplex ultrasound (DUS) and CT angiography (CTA) in the study of arterial vessels, in patients with chronic peripheral arterial disease (PAD) of the lower limbs to undergo endovascular revascularization with the use of intraprocedural digital angiography (DSA).

METHODS

94 patients with obstructive pathology of the arterial axes of the lower limbs were enrolled in the study. In all patients, endovascular revascularization treatment was considered the most suitable therapeutic choice. For this reason, ultrasound and CTA was performed preoperatively in all and based on the data obtained it was decided to classify the arterial tree into five segments: iliac, common femoral, superficial femoral, popliteal and infra-geniculate. According to the degree of stenosis or occlusion, the arteries were scored in no stenotic, stenotic and occluded. The comparison of the data provided by the DUS and the CTA was carried out with reference to the parameters obtained by the DSA.

RESULTS

The results of our experience have shown that in the iliac arterial district DUS proved to be less accurate than CT angiography when compared to DSA (Cohen's Kappa agreement of 0.91 and 1.0, respectively). Good diagnostic concordance were found in the femoro-popliteal district (Cohen's Kappa agreement 33 between 0.96 and 0.93). On the contrary, when the data of the infra-geniculate area were compared, CT angiography showed a net deficiency compared to DSA and DUS (Cohen's k: 0.75).

CONCLUSIONS

Due to its accuracy, high-quality DUS performed by well-trained operators may therefore represent a good alternative to CTA in patients undergoing endovascular revascularization, in order to reduce the use of contrast-enhanced radiological imaging especially when a condition of intolerance to the contrast medium and/or renal insufficiency coexists.

Duplex ultrasound versus CT angiography for the treatment planning of lower-limb arterial disease

PURPOSE

This study aimed to assess the diagnostic accuracy of duplex sonography (DUS) compared with that of computed tomography angiography (CTA) in detecting occlusion and stenosis in peripheral arterial disease (PAD) in candidate patients for endovascular revascularization with intraprocedural digital subtraction angiography (DSA).

METHODS

The study involved 94 patients suffering from PAD who were candidates for endovascular procedures requiring DSA. They were all submitted preoperatively to DUS and CTA. Based on image analysis, five segments of the arterial tree were assessed: iliac, common femoral, superficial femoral, popliteal, and infrageniculate. According to the stenosis or occlusion degree, the arteries were rated as nonstenotic, stenotic, and occluded.

RESULTS

The agreement between DUS and CTA findings using DSA as a reference modality was expressed as a Cohen's kappa (κ) statistic agreement. Our results show that DUS has been less accurate than CTA in evaluating iliac arterial diseases (Cohen's κ agreement of 0.91 and 1.0, respectively) when measured against DSA. We found good diagnostic concordance between DUS and DSA in detecting hemodynamic stenosis and occlusion of the femoro-popliteal axis (Cohen's κ agreement between 0.96 and 0.93). Below the knee, CTA showed even less concordance with DSA (Cohen's κ 0.75).

CONCLUSIONS

Because of its accuracy, high-quality DUS performed by well-trained operators may therefore represent a good alternative to CTA in patients undergoing endovascular revascularization to minimize the use of contrast-enhanced radiological imaging. Nevertheless, preoperative CTA imaging is required in cases of nondiagnostic DUS or when a more complete overview of the vascular tree is needed for complex invasive interventions.

Novel Evaluation Method for Lower Extremity Peripheral Artery Disease With Duplex Ultrasound - Usefulness of Acceleration Time

BACKGROUND

Duplex ultrasound scanning (DUS) plays a major role in less invasive diagnosis and assessment of lesion severity in lower extremity peripheral artery disease (PAD). In this study, we evaluated the efficacy of each DUS parameter measured in patients with PAD and established a simple method for PAD evaluation.

METHODS AND RESULTS

We retrospectively investigated 211 patients (270 limbs) who underwent assessment with both angiography and DUS. During DUS of the common femoral artery (CFA) and popliteal artery, we measured 3 parameters: acceleration time (AcT), peak systolic velocity (PSV), and waveform contour. We compared these parameters with the degree of angiographic stenosis. AcT at the CFA had a significantly higher value in prediction of aortoiliac artery lesions with >50% stenosis (c-index, 0.85; 95% confidence interval (CI), 0.79-0.91), with a sensitivity of 0.82 and specificity of 0.76 at the best cutoff point, compared with PSV and waveform contour (P<0.001, respectively). For femoropopliteal lesions, the ratio of AcT at the popliteal artery to AcT at the CFA is the most predictive parameter, with sensitivity of 0.86 and specificity of 0.92 at the best cutoff point (c-index, 0.93; 95% CI, 0.90-0.97), compared with others (P<0.001, respectively).

CONCLUSIONS

For the assessment of PAD with DUS, AcT and AcT ratio are simple and reliable parameters for evaluating aortoiliac and femoropopliteal artery disease.

Assessment of carotid artery stenosis and lower limb peripheral ischemia before coronary artery bypass grafting operations: a non-randomized clinical trial

BACKGROUND

Atherosclerosis is a systemic disease affecting the coronary, carotid, and lower limb arteries. Cerebrovascular accidents and lower limb ischemia are devastating postoperative complications. We aimed to evaluate the role of non-selective routine arterial duplex scanning in patients undergoing coronary artery bypass grafting (CABG).

METHODS

This non-randomized clinical trial included 360 patients scheduled for elective isolated CABG who were divided into two groups: low-risk (n = 180) and high-risk (n = 180). Both groups underwent preoperative carotid and lower limb ultrasound screening for associated arteriopathy.

RESULTS

16 (8.9%) patients and 22 (12.2%) patients showed ≥70% carotid artery stenosis while 11 patients (6.1%) and 20 patients (11.1%) showed ≥50% lower limb arterial stenosis in the low-risk group and the high-risk group, respectively; though the difference was not statistically significant in both the cases (p > 0.1).

CONCLUSION

Routine preoperative peripheral arterial screening by sonography is a feasible and effective strategy to avoid unnecessary post CABG complications.

TRIAL REGISTRATION

NCT03516929 , Registered in 24 th of April 2018.

Interpretation of peripheral arterial and venous Doppler waveforms: A consensus statement from the Society for Vascular Medicine and Society for Vascular Ultrasound

This expert consensus statement on the interpretation of peripheral arterial and venous spectral Doppler waveforms was jointly commissioned by the Society for Vascular Medicine (SVM) and the Society for Vascular Ultrasound (SVU). The consensus statement proposes a standardized nomenclature for arterial and venous spectral Doppler waveforms using a framework of key major descriptors and additional modifier terms. These key major descriptors and additional modifier terms are presented alongside representative Doppler waveforms, and nomenclature tables provide context by listing previous alternate terms to be replaced by the new major descriptors and modifiers. Finally, the document reviews Doppler waveform alterations with physiologic changes and disease states, provides optimization techniques for waveform acquisition and display, and provides practical guidance for incorporating the proposed nomenclature into the final interpretation report.

Multiscale, patient-specific computational fluid dynamics models predict formation of neointimal hyperplasia in saphenous vein grafts

Stenosis due to neointimal hyperplasia (NIH) is among the major causes of peripheral graft failure. Its link to abnormal hemodynamics in the graft is complex, and isolated use of hemodynamic markers is insufficient to fully capture its progression. Here, a computational model of NIH growth is presented, establishing a link between computational fluid dynamics simulations of flow in the lumen and a biochemical model representing NIH growth mechanisms inside the vessel wall. For all three patients analyzed, NIH at proximal and distal anastomoses was simulated by the model, with values of stenosis comparable to the computed tomography scans.

Doppler ultrasonography of the lower extremity arteries: anatomy and scanning guidelines

Doppler ultrasonography of the lower extremity arteries is a valuable technique, although it is less frequently indicated for peripheral arterial disease than for deep vein thrombosis or varicose veins. Ultrasonography can diagnose stenosis through the direct visualization of plaques and through the analysis of the Doppler waveforms in stenotic and poststenotic arteries. To perform Doppler ultrasonography of the lower extremity arteries, the operator should be familiar with the arterial anatomy of the lower extremities, basic scanning techniques, and the parameters used in color and pulsed-wave Doppler ultrasonography.

Practical Arterial Evaluation of the Lower Extremity

Sonographic examination of the lower extremity arterial system can be time-consuming and arduous if performed in its entirety on every patient who is referred to the vascular sonography laboratory. In fact, most patients can benefit from a tailored noninvasive arterial examination that integrates clinical, physiological, and imaging/Doppler modalities in answering the referring physician s questions. This study provides an algorithm for assessing the type and level of information needed for most patients arriving in the sonography suite with known or suspected peripheral arterial disease.

Screening Algorithm for Aortoiliac Occlusive Disease Using Duplex Ultrasonography–Acquired Velocity Spectra from the Distal External Iliac Artery

Aortoiliac duplex scanning can be difficult to perform owing to the deep location of these vessels. We propose a new method to indirectly screen for aortoiliac disease by performing duplex examination of the distal external iliac artery (DEIA). After performing a preliminary study on 21 patients, the parameters of the Doppler waveform that best distinguish normal from diseased arteries were the presence or absence of reverse flow, peak systolic velocity, and resistance index. These values were used in a derived equation, with the value Y ≥ 0.78 predicting normal proximal inflow. We then studied 118 aortoiliac segments in 81 consecutive patients with arteriography and DEIA duplex ultrasonography. To predict moderate to severe stenosis, duplex ultrasonography had a sensitivity of 95.7%, a specificity of 84.1%, a positive predictive value of 80%, and a negative predictive value of 96.8%. Our formula thus predicted significant disease in 55 of the 118 aortoiliac segments (47%), with these segments needing further arteriographic evaluation. The other 63 limbs can be safely considered as having normal aortoiliac inflow.

Our method accurately screens for aortoiliac disease and is excellent for predicting normal inflow. This information can be used to better plan the intraoperative diagnostic study and intervention.

Spectral analysis of femoral artery blood flow waveforms of conscious domestic cats

The qualitative and quantitative aspects of femoral artery blood flow waveform spectra were evaluated in 15 male and 15 female Persian and mixed breed domestic cats (Felis catus), which were healthy and not sedated, using duplex Doppler ultrasonography (DDU). Spectral Doppler demonstrated a biphasic characteristic in 16 (53.34%) of the animals evaluated, and a triphasic characteristic in the 14 (46.66%) remaining animals. The systolic blood pressure and heart rate values were within the normal range for the species. The quantitative parameters evaluated, based on the spectral Doppler, were as follows: systolic velocity peak (SVP), recent diastolic velocity peak (RDVP), end diastolic velocity peak (EDVP), mean velocity (MV), integral velocity time (ITV), artery diameter (AD), femoral flow volume (FFV), pulsatility index (PI), resistive index (RI), systolic peak acceleration time (AT) and deceleration time (DT). The respective mean values were: 36.41 ± 7.33 cm/s, 4.69 ± 0.90 cm/s, 10.74 ± 2.74 cm/s, 23.06 ± 4.86 cm/s, 3.91 ± 1.05 cm, 0.17 ± 0.04 cm, 0.11 ± 0.08 cm(3), 3.85 ± 0.19, 1.40 ± 0.20, 39.84 ± 7.38 ms, and 114.0 ± 22.15 ms. No significant differences were found between males and females. The analyses carried out on the femoral artery flow spectrum obtained by DDU showed that it is easy to use and highly tolerated in non-sedated, healthy cats. It appears that DDU may be a useful diagnostic technique, but further studies are needed to evaluate how it compares with invasive telemetric methodology or high-definition oscillometric waveform analytic techniques.

Traditional Peripheral Arterial Doppler Waveform Descriptors

Traditional peripheral arterial waveforms have been inconsistently defined and classified. This investigation compares waveform categorization scores from two comparable groups of sonography participants. Group 1 interpreted continuous-wave (CW) and pulsed-wave (PW) Doppler waveforms based on standard text definitions. Group 2 performed the same task following 10 minutes of detailed waveform characterization instructions with accompanying illustrations. Each group comprised 157 participants with an equal number of students, registered sonographers, and physicians. Significant differences were noted between groups 1 and 2 for 60% of CW waveforms and 33% of PW waveforms ( P < .05). In group 2, American Registry for Diagnostic Sonography (ARDMS)–registered sonographers had significantly higher CW scores than students and physicians ( P < .0001); registered vascular technologists and multispecialty ARDMS-certified sonographers had significantly higher PW scores than students, Registered Diagnostic Medical Sonographer (RDMS)–certified sonographers, and physicians ( P = .0086 and P = .0295, respectively). This study emphasizes the contribution of sonographers in arterial Doppler waveform categorization and underscores the need for standardization and education.

Supervised exercise versus primary stenting for claudication resulting from aortoiliac peripheral artery disease: six-month outcomes from the claudication: exercise versus endoluminal revascularization (CLEVER) study

BACKGROUND

Claudication is a common and disabling symptom of peripheral artery disease that can be treated with medication, supervised exercise (SE), or stent revascularization (ST).

METHODS AND RESULTS

We randomly assigned 111 patients with aortoiliac peripheral artery disease to receive 1 of 3 treatments: optimal medical care (OMC), OMC plus SE, or OMC plus ST. The primary end point was the change in peak walking time on a graded treadmill test at 6 months compared with baseline. Secondary end points included free-living step activity, quality of life with the Walking Impairment Questionnaire, Peripheral Artery Questionnaire, Medical Outcomes Study 12-Item Short Form, and cardiovascular risk factors. At the 6-month follow-up, change in peak walking time (the primary end point) was greatest for SE, intermediate for ST, and least with OMC (mean change versus baseline, 5.8±4.6, 3.7±4.9, and 1.2±2.6 minutes, respectively; P<0.001 for the comparison of SE versus OMC, P=0.02 for ST versus OMC, and P=0.04 for SE versus ST). Although disease-specific quality of life as assessed by the Walking Impairment Questionnaire and Peripheral Artery Questionnaire also improved with both SE and ST compared with OMC, for most scales, the extent of improvement was greater with ST than SE. Free-living step activity increased more with ST than with either SE or OMC alone (114±274 versus 73±139 versus -6±109 steps per hour), but these differences were not statistically significant.

CONCLUSIONS

SE results in superior treadmill walking performance than ST, even for those with aortoiliac peripheral artery disease. The contrast between better walking performance for SE and better patient-reported quality of life for ST warrants further study.

CLINICAL TRIAL REGISTRATION

URL: http://clinicaltrials.gov/ct/show/NCT00132743?order=1. Unique identifier: NCT00132743.

Echocardiographic evaluation of aorto-iliac occlusive disease

Several studies demonstrated feasibility of visual assessment of the common femoral artery Doppler waveform, in an indirect evaluation of aorto-iliac segment stenosis. Patients with cardiac diseases referred for echocardiography often have coexistent arterial pathology. Since many of them are potential candidates for endovascular procedures, we decided to study, whether echocardiography can be useful for detection of aorto-iliac occlusive disease. We evaluated 92 patients with abdominal aortic aneurysm or peripheral artery occlusive disease, referred from the vascular surgery department for cardiac evaluation before surgery. At the end of an echocardiographic examination, evaluation of flow in the distal external iliac arteries with an echocardiographic probe was performed. The Doppler waveform was classified into normal—with early diastolic flow reversal or abnormal—without early diastolic flow reversal. Echocardiographic results were compared in a blinded fashion with reports from computed tomography angiography. Overall there were 58 iliac segments with significant (≥70%) area stenosis or occlusion and 126 iliac segments without significant disease on computed tomography angiography. Abnormal Doppler waveform was found in 56 out of 58 abnormal iliac segments—sensitivity 97%, and normal waveform was found in 106 out of 126 normal iliac segments—specificity 84%. Positive predictive value of abnormal Doppler waveform for significant iliac disease was 74%, and negative predicting value was 98%. Detection of significant stenoses in aorto-iliac segments is feasible with echocardiography. Further studies are necessary to evaluate its potential utility in a population of patients with cardiac disease referred for echocardiographic study.

Femoral/Axillary Volume Flow Ratio as a New Index for the Assessment of Iliac Atherosclerosis

Objective: To measure the arterial volume flow (VF) with duplex scan, calculate femoral/axillary VF ratio, and discuss its applicability as a new index for the hemodynamic significance of an aorto-iliac occlusive lesion. Methods: Several measures of VF were obtained consecutively with duplex scan in both common femoral and axillary arteries of healthy volunteers with no signs of atherosclerosis and patients with documented evidence of occlusive aorto-iliac disease with segmental pressure measurement. Then the patient group was sent to complimentary evaluation for a second confirmatory examination. Results: There were a total of 635 measures of VF performed in 10 healthy volunteers and 8 patients with severe iliac stenoses or occlusion, 2 of then with bilateral disease. When comparing normal participants and patients with severe iliac stenoses or occlusion, there was statistical significant difference between these 2 groups (P < .01 Mann-Whitney). Similar result was found when comparing patient with diseased limbs with their own contralateral normal side (P < .05 Wilcoxon). And measuring the VF only during the systolic phase was a much more sensitive parameter for differentiating the normal from the diseased. Besides that a good correlation between proximal thigh pressure index and femoral/axillary systolic flow ratio was found in the patient group (P < .01 Spearman correlation). Conclusion: The femoral/axillary VF ratio is useful in assessing the hemodynamic significance of aorto-iliac disease, and the systolic femoral-axillary ratio may also be useful as a follow-up tool.

Diagnostic accuracy of contrast-enhanced magnetic resonance angiography and duplex ultrasound in patients with peripheral vascular disease

INTRODUCTION

Noninvasive techniques such as duplex ultrasound (DU) and contrast-enhanced magnetic resonance angiography (CE-MRA) are valid alternatives in the preoperative evaluation of such patients. Our aim is to assess the diagnostic accuracy of CE-MRA and DU in patients with peripheral arterial disease (PAD).

METHODS

Forty consecutive patients underwent DU, hybrid CE-MRA, and digital subtraction angiography (DSA). Magnetic resonance angiography and DSA images were evaluated independently and in a blinded fashion. Every segment was graded as normal, stenosed less than 50%, stenosed more than 50%, or occluded.

RESULTS

There were 1720 segments for analysis. Duplex ultrasound depicting stenosis >50% demonstrated a sensitivity (S) 81.4%, specificity (E) 99%, positive predictive value (PPV) 96.2%, and negative predictive value (NPV) 94.8%. Occlusions showed S 90%, E 97%, PPV 98.1%, and NPV 88.4%. Magnetic resonance angiography depicting stenosis >50% demonstrated a S 91%, E 99%, PPV 96.7%, and NPV 97.6%. Occlusions showed S 95.4%, E 98%, PPV 98.4%, and NPV 94.7%.

CONCLUSION

Combined CE-MRA and DU is the first diagnostic approach in the preoperative assessment of PAD, leading to the use of DSA for selected cases.

Reliability of preoperative duplex scanning in designing a therapeutic strategy for chronic lower limb ischemia

The objective of this study was to compare the treatment plan designed on the basis of preoperative duplex scanning evaluation of the critical limb ischemia with the treatment plan finally carried out, after assessing the findings obtained during surgical or endovascular treatment. Over a period of 51 months a preoperative duplex scanning study was carried out in 335 consecutive patients with chronic critical ischemia, to design the best therapeutic strategy. Agreement between both plans were as follows: 80%, 82,7% and 59% in the examinations of the iliac arteries, femoropopliteal or tibial arteries respectively. The operation plan was more frequently modified due to a duplex scanning failure in procedures involving the the distal vessels(10 of 44 [22.7%], p < 0.01). In conclusion, duplex scanning evaluation of patients with occlusive arterial disease of the lower limbs permits the design of both a medical and a surgical or endovascular treatment plan with a high level of agreement with the findings obtained during the revascularization procedure.

Confusion of Peripheral Arterial Doppler Waveform Terminology

Characterization of peripheral arterial waveforms is basic to the diagnosis of vascular disease. Surveys indicate inconsistent application of traditional waveform descriptors. This study reviews literature to identify areas of confusion. Publications were reviewed to determine whether triphasic, biphasic, and monophasic terms were defined; if biphasic was linked with diastolic flow reversal; whether pandiastolic flow was associated with biphasic or monophasic terminology; and whether waveform illustrations had a zero baseline. Ninety-four publications were reviewed. Triphasic and monophasic were defined in 81%, biphasic in 48%. Biphasic was classified with flow reversal in 38%. Pandiastolic flow was not addressed in 57% but associated with monophasic in 47% and biphasic in 5%. Twenty-one percent of the publications had an illustration without a zero-flow baseline. This review suggests a lack of consensus when classifying arterial blood flow with traditional waveform descriptors. Waveform characterization inconsistencies are undermining comprehension of Doppler principles and may lead to inappropriate testing. A multisocietal consensus panel should accept responsibility for resolving this issue.

Análise espectral segmentar no seguimento de pacientes revascularizados

CONTEXTO: Pacientes tratados por revascularização arterial (enxertos e angioplastias) nos membros inferiores acometidos por doença arterial oclusiva periférica foram seguidos por até 2 anos pós-tratamento usando ultrassom vascular (análise espectral segmentar, AES). OBJETIVO: Demonstrar que a AES pode ser utilizada no seguimento dos pacientes tratados por doença arterial oclusiva periférica. MÉTODOS: As medidas de AES realizadas foram: velocidade sistólica de pico, índice de pulsatilidade e forma da onda de velocidade de fluxo. Essas foram comparadas em cada paciente no pré e pós-tratamento (com intervalos de 3 meses) para diagnóstico de perviedade. RESULTADOS: Medidas realizadas no pós-operatório nas artérias imediatamente distais aos segmentos tratados mostraram aumento consistente de velocidade sistólica de pico e índice de pulsatilidade com mudanças na forma da onda de velocidade de fluxo de unifásica para bi ou trifásica. A velocidade sistólica de pico e o índice de pulsatilidade aumentaram respectivamente em 92,26 e 98,2% (tratamentos no segmento aorto-ilíaco), em 112,83 e 62,39% (tratamentos no segmento fêmoro-poplíteo) e em 149,08 e 28,8% (tratamentos no segmento poplíteo-tibial). Tais mudanças nos padrões de velocidade de fluxo ocorreram em todos os pacientes e permaneceram quase inalteradas enquanto os tratamentos estivessem pérvios. Quando ocorria falência nos tratamentos (oclusões ou estenoses hemodinamicamente significantes), os parâmetros caíam a níveis similares aos de antes do tratamento. Se a falência do tratamento era corrigida por nova revascularização (enxerto ou angioplastia), os parâmetros de AES voltavam a se comportar como após o tratamento inicial. CONCLUSÃO: A AES pode ser usada no seguimento dos pacientes com revascularização dos membros devido a doença arterial oclusiva periférica, demonstrando tanto a perviedade quanto a falência do tratamento.

Kissing stents in the aortic bifurcation--a valid reconstruction for aorto-iliac occlusive disease

OBJECTIVE

To evaluate outcome and patency predicting factors of kissingstent treatment for aorto iliac occlusive disease (AIOD).

METHODS

Patients treated with kissingstents for AOID between 1995 and 2004 at a tertiary referral center were identified through local databases. Chart review and preoperative images were used for TASC and Fontaine classification. Follow-up consisted of clinical exams, ABI and/or duplex. Patency rates were estimated by Kaplan-Meier analysis, and Cox multivariate regression was used to determine factors associated with patency.

RESULTS

173 consecutive patients (46% male, mean 64 years) were identified. TASC distribution was: A 15%, B 34%, C 10%, D 41%. Mean follow-up was 36 months (range: 1-144). 30-day mortality was 1% (2 patients), and 1-year survival was 91% (157 patients). 2 patients underwent late, open conversion and 13 patients suffered minor puncture site complications. Primary, assisted primary and secondary patency was: 97%, 99% and 100%, and 83%, 90% and 95% at twelve and 36 months respectively. There was no significant difference in patency between the TASC groups. Patency was significantly worse for patients in Fontaine class III.

CONCLUSIONS

Aortoiliac kissing stents is a valid alternative to open repair for TASC A-D lesions. The procedure has low mortality and morbidity and good patency at 3 years.

Gadolinium-enhanced Magnetic Resonance Angiography, Colour Duplex and Digital Subtraction Angiography of the Lower Limb Arteries from the Aorta to the Tibio-peroneal Trunk in Patients with Intermittent Claudication

OBJECTIVES

To evaluate the sensitivity, specificity, positive and negative predictive value of contrast-enhanced (gadolinium) magnetic resonance imaging (CE-MRA) and colour duplex ultrasound (CDU) of lower limb arteries.

DESIGN

Prospective, single centre study.

MATERIAL AND METHODS

A consecutive series of 58 patients with intermittent claudication (IC) were examined with CE-MRA and CDU from the infrarenal aorta to the tibio-peroneal trunk with digital subtraction angiography (DSA) as reference. The arterial tree was divided into 15 segments, pooled into three regions; suprainguinal, thigh and knee. Sensitivity, specificity, positive and negative predictive values for significant obstructions were calculated. Cohen Kappa statistics was used to establish agreement between the three methods.

RESULTS

The sensitivity (specificity in parentheses) for significant obstructions in the suprainguinal region were 96% (94%) for CE-MRA and 91% (96%) for CDU, in the thigh region 92% (95%) for CE-MRA and 76% (99%) for CDU, and in the knee region 93% (96%) for CE-MRA and 33% (98%) for CDU. CDU failed to visualize 10% of suprainguinal, 2% of thigh and 13% of knee-region arterial segments.

CONCLUSIONS

Both CE-MRA and CDU are good alternatives to DSA in the suprainguinal- and thigh-region. In the knee region only CE-MRA can be relied upon as an alternative to DSA. Imaging by CDU is not suited to situations were evaluation of runoff vessels is important.

Value of the duplex waveform at the common femoral artery for diagnosing obstructive aortoiliac disease

PURPOSE

To evaluate the accuracy, predictive value, and observer agreement of the duplex ultrasound waveform at the common femoral artery as a marker of significant aortoiliac disease in a large group of consecutive patients who underwent a diagnostic workup for peripheral arterial disease in a vascular unit.

METHODS

In 191 consecutive patients (381 aortoiliac segments), we classified the duplex ultrasound waveform at the common femoral artery as triphasic, biphasic, sharp monophasic, or poor monophasic. The waveforms were then compared with the findings of magnetic resonance angiography of the aortoiliac segment and peripheral runoff vessels. We calculated the diagnostic accuracy of the duplex waveform for detecting >50% obstructive disease of the aortoiliac segment and determined the observer agreement for classifying the duplex waveforms done by two independent observers.

RESULTS

Magnetic resonance angiography showed obstruction in 152 (39.9%) of 381 aortoiliac segments in 191 patients. The presence of a poor monophasic waveform, encountered in 91 (24.3%) of 375 segments, was a reliable sign of significant aortoiliac disease, with a positive predictive value of 92%. Other waveforms were nondiagnostic for aortoiliac obstructive disease. The sharp monophasic waveform reliably predicted occlusive disease of the superficial femoral artery that was seen in 17 of 23 instances. There was good observer agreement for classifying duplex waveforms (kappa(w)= 0.85; 95% confidence interval, 0.80 to 0.89).

CONCLUSION

The poor monophasic duplex waveform at the common femoral artery is in itself an accurate marker of aortoiliac obstructive disease. Other waveforms are nondiagnostic for aortoiliac disease.

An evaluation of the efficacy of methods used in screening for lower-limb arterial disease in diabetes

OBJECTIVE

Foot-related disease is the most common cause for hospital admission among the diabetic population. Lower-limb peripheral arterial occlusive disease (PAOD) is a major risk factor in diabetic foot disease. Screening for PAOD commonly includes foot pulses and the ankle-brachial pressure index (ABPI) and/or the toe-brachial pressure index (TBI), but concerns persist regarding their accuracy. We evaluated the efficacy of several commonly used screening methods in different subject populations.

RESEARCH DESIGN AND METHODS

We studied 130 limbs in 68 individuals with no critical ischemia over 8 months. Limbs were grouped on the basis of the presence or absence of diabetes, clinically detectable peripheral neuropathy, and PAOD identified on color duplex imaging. Comparative analyses of foot pulses, the ABPI, the TBI, and distal Doppler waveform analysis were performed.

RESULTS

Foot pulses, the TBI, and qualitative waveform analyses were highly sensitive screening methods in individuals with and without diabetes. However, detectable peripheral neuropathy was associated with a reduced sensitivity and poor specificity of foot pulses, a reduction in sensitivity of the ABPI (71 to 38%), and a reduction in specificity of the TBI (81 to 61%) and qualitative waveform analysis (96 to 66%). Quantitative analysis failed to detect disease with severely damped and low-intensity signals.

CONCLUSIONS

Screening tools that are effective in screening for lower-limb PAOD in the nondiabetic population are less efficacious in diabetes, particularly in the presence of detectable peripheral neuropathy. Qualitative waveform analysis and the TBI were demonstrated to be more effective screening methods than the ABPI and foot pulses particularly in high-risk limbs with detectable peripheral neuropathy.

Segmental Waveform Analysis in the Diagnosis of Peripheral Arterial Occlusive Diseases

The duplex exam is widely used in the diagnosis of peripheral arterial occlusive disease. It presents some drawbacks, however, such as calcified plaques, sequential stenosis, and time-consuming examinations. A type of waveform analysis, referred to in this study as segmental analysis, was conducted to try to find solutions to these problems. Parameters of waveform analysis (peak systolic velocity, acceleration time, pulsatility, and resistance indices) taken at the common femoral and popliteal arteries in 177 arterial segments (aortoiliac and femoropopliteal) were compared to angiography results in a prospective manner. The statistical analysis showed an accuracy rate above 95% for all parameters in defining hemodynamic-significant (stenosis and occlusions) lesions in both segments. Also, a combination of measurements (parallel tests) was used to differentiate between hemodynamic-significant stenosis and occlusions, showing sensitivity and specificity rates between 84.8% and 94.8%. Findings from this study show that the hemodynamics of an arterial segment can be evaluated by segmental waveform analysis. It can also be used as a screening test for peripheral arterial occlusive diseases alone or combined with the standard duplex color exam.

The Nitinol SMART Stent vs Wallstent for Suboptimal Iliac Artery Angioplasty: CRISP-US Trial Results

PURPOSE

The Cordis Randomized Iliac Stent Project-US (CRISP-US) trial evaluated, with an equivalence design, the performance of the shape memory alloy recoverable technology (SMART) nitinol self-expanding stent and the stainless steel Wallstent for treating iliac artery disease after suboptimal percutaneous transluminal angioplasty (PTA).

MATERIALS AND METHODS

This multicenter, prospective, randomized trial comprised 203 patients with chronic limb ischemia who received either the SMART stent (n = 102) or the Wallstent (n = 101) after suboptimal PTA. The primary equivalence end point was a composite of 9-month restenosis, 30-day death, and 9-month target vessel revascularization. Functional, clinical, and hemodynamic assessments were made at hospital discharge and at 1, 6, 9, and 12 months.

RESULTS

The 9-month composite end point rate was equivalent for the SMART stent and Wallstent (6.9% vs 5.9%), with low rates of restenosis (3.5% vs 2.7%), death (2.0% vs 0.0%), and revascularization (2.0% vs 4.0%) in the two groups. Primary patency at 12 months was 94.7% and 91.1% with the SMART stent and Wallstent, respectively. Functional and hemodynamic improvement was also comparable between the groups. The acute procedural success rate was higher in the SMART stent group (98.2% vs 87.5%; P =.002). The frequency of major adverse events was similar at 1 year (4.9% vs 5.9%).

CONCLUSIONS

The performance of the SMART stent was equivalent to that of the Wallstent for treating iliac artery stenosis. The design characteristics of the SMART stent may contribute to greater procedural success and more accurate stent deployment.