Limitations of ultrasonic duplex scanning for diagnosing lower limb arterial stenoses in the presence of adjacent segment disease

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.

Non-Coronary Atherosclerotic Arterial Disease: Where Are We Now?

Lower extremity peripheral artery and upper extremity artery disease are significant vascular conditions with distinct clinical presentations and diagnostic and therapeutic approaches. The lower extremity peripheral artery is associated with worse major adverse cardiovascular events compared with coronary artery disease, but often remains underdiagnosed and undertreated. Upper extremity artery disease encompasses a range of clinical presentations resulting from atherosclerosis and other obstructive lesions in arteries such as the subclavian artery and brachiocephalic trunk. While atherosclerosis is a common cause, non-atherosclerotic factors can also influence distal lesions. This review aims to synthesize existing knowledge on both conditions, encompassing risk factors, clinical manifestations, diagnostic modalities, and treatment options. Improved awareness and early intervention can mitigate complications and enhance patient outcomes for lower extremity peripheral artery and upper extremity artery disease.

ACR Appropriateness Criteria® Lower Extremity Arterial Claudication-Imaging Assessment for Revascularization: 2022 Update

Arterial claudication is a common manifestation of peripheral artery disease. This document focuses on necessary imaging before revascularization for claudication. Appropriate use of ultrasound, invasive arteriography, MR angiography, and CT angiography are discussed. The ACR Appropriateness Criteria are evidence-based guidelines for specific clinical conditions that are reviewed annually by a multidisciplinary expert panel. The guideline development and revision process support the systematic analysis of the medical literature from peer reviewed journals. Established methodology principles such as Grading of Recommendations Assessment, Development, and Evaluation or GRADE are adapted to evaluate the evidence. The RAND/UCLA Appropriateness Method User Manual provides the methodology to determine the appropriateness of imaging and treatment procedures for specific clinical scenarios. In those instances where peer reviewed literature is lacking or equivocal, experts may be the primary evidentiary source available to formulate a recommendation.

Lower Extremity Peripheral Artery Disease: Contemporary Epidemiology, Management Gaps, and Future Directions: A Scientific Statement From the American Heart Association

Lower extremity peripheral artery disease (PAD) affects >230 million adults worldwide and is associated with increased risk of various adverse clinical outcomes (other cardiovascular diseases such as coronary heart disease and stroke and leg outcomes such as amputation). Despite its prevalence and clinical importance, PAD has been historically underappreciated by health care professionals and patients. This underappreciation seems multifactorial (eg, limited availability of the first-line diagnostic test, the ankle-brachial index, in clinics; incorrect perceptions that a leg vascular disease is not fatal and that the diagnosis of PAD would not necessarily change clinical practice). In the past several years, a body of evidence has indicated that these perceptions are incorrect. Several studies have consistently demonstrated that many patients with PAD are not receiving evidence-based therapies. Thus, this scientific statement provides an update for health care professionals regarding contemporary epidemiology (eg, prevalence, temporal trends, risk factors, and complications) of PAD, the present status of diagnosis (physiological tests and imaging modalities), and the major gaps in the management of PAD (eg, medications, exercise therapy, and revascularization). The statement also lists key gaps in research, clinical practice, and implementation related to PAD. Orchestrated efforts among different parties (eg, health care providers, researchers, expert organizations, and health care organizations) will be needed to increase the awareness and understanding of PAD and improve the diagnostic approaches, management, and prognosis of PAD.

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.

Diabetic foot disease: From the evaluation of the “foot at risk” to the novel diabetic ulcer treatment modalities

The burden of diabetic foot disease (DFD) is expected to increase in the future. The incidence of DFD is still rising due to the high prevalence of DFD predisposing factors. DFD is multifactorial in nature; however most of the diabetic foot amputations are preceded by foot ulceration. Diabetic peripheral neuropathy (DPN) is a major risk factor for foot ulceration. DPN leads to loss of protective sensation resulting in continuous unconscious traumas. Patient education and detection of high risk foot are essential for the prevention of foot ulceration and amputation. Proper assessment of the diabetic foot ulceration and appropriate management ensure better prognosis. Management is based on revascularization procedures, wound debridement, treatment of infection and ulcer offloading. Management and type of dressing applied are tailored according to the type of wound and the foot condition. The scope of this review paper is to describe the diabetic foot syndrome starting from the evaluation of the foot at risk for ulceration, up to the new treatment modalities.

A Robotic Ultrasound Scanner for Automatic Vessel Tracking and Three-Dimensional Reconstruction of B-Mode Images

Locating and evaluating the length and severity of a stenosis is very important for planning adequate treatment of peripheral arterial disease (PAD). Conventional ultrasound (US) examination cannot provide maps of entire lower limb arteries in 3-D. We propose a prototype 3D-US robotic system with B-mode images, which is nonionizing, noninvasive, and is able to track and reconstruct a continuous segment of the lower limb arterial tree between the groin and the knee. From an initialized cross-sectional view of the vessel, automatic tracking was conducted followed by 3D-US reconstructions evaluated using Hausdorff distance, cross-sectional area, and stenosis severity in comparison with 3-D reconstructions with computed tomography angiography (CTA). A mean Hausdorff distance of 0.97 ± 0.46 mm was found in vitro for 3D-US compared with 3D-CTA vessel representations. To evaluate the stenosis severity in vitro, 3D-US reconstructions gave errors of 3%-6% when compared with designed dimensions of the phantom, which are comparable to 3D-CTA reconstructions, with 4%-13% errors. The in vivo system's feasibility to reconstruct a normal femoral artery segment of a volunteer was also investigated. These results encourage further ergonomic developments to increase the robot's capacity to represent lower limb vessels in the clinical context.

Assessment of Carotid Artery Stenosis and the Use of Statins

General thinking has previously centered on managing carotid artery stenosis (CAS) by carotid endarterectomy and subsequently, stenting for higher risk patients. However for CAS and other forms of vascular disease, especially when asymptomatic, there is new emphasis on defining underlying mechanisms. Knowledge of these mechanisms can lead to medical treatments that result in possible atherosclerotic plaque stabilization, and even plaque regression, including in the patient with CAS. For now, the key medication class for a medical approach are the statins. Their use is supported by good cardiovascular clinical trial evidence including some directed carotid artery studies, especially with a demonstrated decrease in carotid intima-media thickness. Procedural controversy still exists but the current era in medicine offers significant support for medical management of asymptomatic CAS while techniques to recognize the vulnerable plaque evolve. If CAS converts to a symptomatic status, early referral for endarterectomy or stenting is indicated.

Duplex Ultrasound Assessment of Native Stenoses in the Superficial Femoral and Popliteal Arteries

Purpose: To evaluate duplex ultrasonography (DUS) in the assessment of femoropopliteal stenoses comparing a single native stenosis (SNS) to multisegmental native stenoses (MNS). Methods: Among the 1284 patients treated for atherosclerotic occlusive disease involving the femoropopliteal segment between November 2002 and November 2012, 139 patients (97 men; mean age 68±8 years) with 142 SNS or 143 MNS in 79 and 60 patients, respectively, were eligible for this retrospective analysis. The peak systolic velocity ratios with proximal (PSVRprox) and distal (PSVRdist) reference for the 285 lesions were compared with their respective angiographic stenosis grade as measured by 2 independent readers using quantitative vascular analysis to ensure objectivity. Receiver operating characteristic curve analysis was used to evaluate sensitivity, specificity, and the optimal thresholds of PSV and PSVR for detection of stenoses by grade (>50%, >70%, or >80% diameter stenosis). The area under the curve (AUC) values of dependent and independent receiver operating characteristic curves were compared. Results: For SNS, correlation of PSVRprox to diameter stenosis (R=0.88) was higher (p<0.001) than the correlation for MNS (R=0.78). In the SNS group, the AUC for detecting a >50% (0.99±0.01), >70% (0.98±0.01), and >80% (0.96±0.01) stenosis with PSVRprox was significantly higher than in the MNS group [AUC50% 0.93±0.02 (p=0.01), AUC70% 0.92±0.02 (p=0.02), and AUC80% 0.87±0.03 (p=0.003)]. The optimal thresholds for detecting >50%, >70%, and >80% stenoses for SNS using PSVRprox were 2.6, 3.3, and 3.9, respectively. For MNS, the optimal thresholds of PSVRprox were 2.6, 3.4, and 3.9, respectively, with respective sensitivities of 87%, 81%, and 75%; respective specificities of 93%, 90%, and 82%; negative predictive values of 45%, 64%, and 74%; and positive predictive values of 99%, 95%, and 83%. Conclusion: DUS is an optimal tool for quantification of SNS. However, a multisegment setting has a significant negative impact on the quantification of femoropopliteal artery stenosis.

Peripheral arterial disease: Epidemiology, natural history, diagnosis and treatment

Lower extremity peripheral arterial disease (PAD) affects approximately 10% of the American population, with 30% to 40% of these patients presenting with claudication symptoms. The prevalence of PAD increases with age and the number of vascular risk factors. More importantly, it is a marker of atherosclerotic disease burden, and is associated with increased mortality from cardiovascular and cerebrovascular causes. There have been recent advances in noninvasive imaging, endovascular approaches for revascularization, and aggressive risk factor management for prevention of cardiac and cerebrovascular complications in PAD. There is now a trend toward aggressive risk factor modification and endovascular revascularization for most patients, with surgical interventions reserved for certain situations only. In the present article, a systematic review is presented, focusing on the key aspects of the disease epidemiology, presentation, natural history, diagnosis and available management options.

Chapter II: Diagnostic methods

Non-invasive vascular studies can provide crucial information on the presence, location, and severity of critical limb ischaemia (CLI), as well as the initial assessment or treatment planning. Ankle-brachial index with Doppler ultrasound, despite limitations in diabetic and end-stage renal failure patients, is the first-line evaluation of CLI. In this group of patients, toe-brachial index measurement may better establish the diagnosis. Other non-invasive measurements, such as segmental limb pressure, continuous-wave Doppler analysis and pulse volume recording, are of limited accuracy. Transcutaneous oxygen pressure (TcPO(2)) measurement may be of value when rest pain and ulcerations of the foot are present. Duplex ultrasound is the most important non-invasive tool in CLI patients combining haemodynamic evaluation with imaging modality. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) are the next imaging studies in the algorithm for CLI. Both CTA and MRA have been proven effective in aiding the decision-making of clinicians and accurate planning of intervention. The data acquired with CTA and MRA can be manipulated in a multiplanar and 3D fashion and can offer exquisite detail. CTA results are generally equivalent to MRA, and both compare favourably with contrast angiography. The individual use of different imaging modalities depends on local availability, experience, and costs. Contrast angiography represents the gold standard, provides detailed information about arterial anatomy, and is recommended when revascularisation is needed.

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.

Estudo comparativo de eco-Doppler com arteriografia na avaliação da doença oclusiva aorto-ilíaca

Contexto: A arteriografia com contraste (AC) tem sido o exame tradicional de avaliação de pacientes com suspeita de doença oclusiva aorto-ilíaca (DOAI). Recentemente, métodos menos invasivos, como a eco-Doppler, têm sido usados com a mesma finalidade. Objetivo: Comparar prospectivamente a eco-Doppler com a AC e eventual manometria arterial direta (MAD) na avaliação pré-operatória de pacientes com suspeita de DOAI. Métodos: Foram submetidos a eco-Doppler e a AC 125 pacientes internados para tratamento de doença arterial oclusiva dos membros inferiores, avaliando comparativamente 552 segmentos da aorta infrarrenal e das artérias ilíacas comum e externa. As lesões encontradas foram classificadas em cinco categorias: 1) normal e estenose leve (0 a 19%); 2) estenose moderada (20 a 49%); 3) estenose significativa (50 a 79%); 4) estenose crítica (80 a 99%); e 5) oclusão total. A MAD foi usada em 19 segmentos de 15 pacientes para classificar lesões limítrofes entre duas categorias. Foram calculados índices de validade (sensibilidade, especificidade, valor preditivo positivo, valor preditivo negativo e acurácia) para distinguir lesões hemodinamicamente significativas de não-significativas e para distinguir estenoses críticas de oclusões. O padrão-ouro foi AC, complementado pela MAD. Foram também calculados coeficientes de correlação kappa entre arteriografias e eco-Doppler para o conjunto dos segmentos aorto-ilíacos. Resultados: Lesões clinicamente relevantes (estenoses de 50 a 99% e oclusões totais) foram observadas na eco-Doppler em 163 segmentos (29,5%) e na AC em 158 segmentos (28,6%). A eco-Doppler mostrou altos índices de validade para distinguir lesões hemodinamicamente significativas de lesões não-significativas em todos os segmentos (acurácia = 92%; kappa = 0,81) e para diferenciar estenoses críticas de oclusões (acurácia = 86%; kappa = 0,73). Os índices de correlação entre os resultados das eco-Doppler e das AC foram ótimos em todos os segmentos aorto-ilíacos. Conclusão: A eco-Doppler apresenta elevados índices de validade e ótimos coeficientes de correlação com a AC na avaliação de pacientes com suspeita de DOAI.

A Prospective Feasibility Study of Duplex Ultrasound Arterial Mapping, Digital-Subtraction Angiography, and Magnetic Resonance Angiography in Management of Critical Lower Limb Ischemia by Endovascular Revascularization

Duplex ultrasound arterial mapping (DUAM) allows precise evaluation of peripheral vascular disease (PVD). However, magnetic resonance angiography (MRA) and digital-subtraction angiography (DSA) are the diagnostic tools used most frequently prior to intervention. Our aim was to compare clinical pragmatism, hemodynamic outcomes, and cost-effectiveness when using DUAM alone compared to DSA or MRA as preoperative assessment tools for endovascular revascularization (EvR) in critical lower limb ischemia (CLI). From 2002 through 2005, 465 patients were referred with PVD. Of these, 199 had CLI and 137 required EvR. Preoperative diagnostic evaluation included DUAM (n = 41), DSA (n = 50), or MRA (n = 46). EvR was aortoiliac in 27% of cases and infrainguinal in 73%. Patients were assessed at day 1, 6 weeks, 3 months, and 6 months. Composite end points were relief of rest pain, ulcer/gangrene healing, and increase in perfusion pressure, as measured by ankle-brachial index (ABI) and digital pressures. Patency by DUAM, limb salvage, morbidity, mortality, length of stay, and cost-effectiveness were compared between groups using nonparametric t-test, analysis of variance, and Kaplan-Meier analysis. The three groups were comparable in terms of age, sex, comorbidity, and Society for Vascular Surgery/International Society of Cardiovascular Surgery clinical classification. Six-month mean improvement in ABI in the DUAM group was comparable to that in the DSA group (P = 0.25) and significantly better than that in the MRA group (P < 0.05). Six-month patency rates for the DUAM group were comparable to those in the DSA group (P = 0.68, relative risk [RR] = 0.74, 95% confidence interval [CI] 0.18-2.99) and superior to that in the MRA group (P = 0.022, RR = 0.255, 95% CI 0.09-0.71). Length of hospital stay was lower in the DUAM group compared with the DSA group (P < 0.0001) and the MRA group (P = 0.0003). The cost of DUAM is lower than that of both DSA and MRA. DUAM accurately identified the total number of target lesions for revascularization; however, MRA overestimated it. Our results indicate that DUAM is outstanding when compared with other available modalities as a preoperative imaging tool in a successful EvR program. DUAM is a minimally invasive preoperative evaluation for EvR and offers precise consecutive data with patency and limb salvage rates comparable to EvR based on DSA and superior to MRA. We believe that our feasibility study has established DUAM as an economically proficient primary modality for investigating patients with CLI that significantly shortens length of hospital stay.

Lower Extremity Revascularization Based on Intraoperative Arteriography

The traditional approach to patients with lower extremity ischemia involves "diagnostic" arteriography performed in a radiology angiography suite prior to a separate revascularization in an operating room suite. This time-honored and staged approach has the disadvantage of an associated significant angiographic complication rate. Furthermore, in view of the accuracy of noninvasive testing and the capacity for intraoperative arteriography, this separation of diagnostic and reparative techniques may be outdated and cost-ineffective. A combination of the two in a modern operating room is a more logical approach.

Influence of multiple stenoses on echo-Doppler functional diagnosis of peripheral arterial disease: a numerical and experimental study

The objective of this paper was to evaluate the ability of the peak systolic velocity ratio (PSVR) and pressure drop (DeltaP) to detect and grade multiple stenoses in lower limb mimicking arteries. Numerical simulations and experiments in vascular phantoms allowing ultrasound duplex scanning and pressure measurements were used to investigate simple and double stenotic arterial segments. Inter-stenotic distance, severity of the distal stenosis, flow rate and flow profile (steady or pulsatile) were the tested parameters. The three-dimensional simulations considered the turbulent two-equation Wilcox model. Agreements were observed between the experimental and numerical results for DeltaP and PSVR. The maximum PSVR along the artery was shown to be mainly influenced by the severity of the most important stenosis. However, mutual interactions of both stenoses on hemodynamics were noted. By using the clinical PSVR threshold used to diagnose critical lesions (PSVR > or = 2), its longitudinal evolution along the artery poorly reflected the length of the lesion or the impact of surrounding stenoses. This investigation confirms the interaction between adjacent stenoses on hemodynamics and its impact on the Doppler ultrasound index PSVR.

Diagnosis of arterial occlusive disease of the upper extremities: comparison of color duplex sonography and angiography

PURPOSE

The aim of this study was to assess the abilities of color duplex sonography (CDUS) to detect and characterize arterial occlusive disease of the upper extremities.

METHODS

We prospectively compared the results of CDUS with those of intra-arterial digital subtraction angiography, which were considered definitive, in patients with symptomatic arterial occlusive disease of the upper extremities. In each extremity, we visualized 9 arterial segments, which were each evaluated for stenoses and occlusions. Each segment was categorized on each imaging modality as not significantly narrowed (narrowed by <50%), significantly narrowed (narrowed by > or =50% but <100%), or occluded (100%).

RESULTS

We examined a total of 578 segments in 57 patients (34 men and 23 women) with a mean age of 50 years (range, 20-74 years). CDUS had a sensitivity, a specificity, a positive predictive value, a negative predictive value, and an accuracy of 98%, 99%, 97%, 99.5%, and 99%, respectively, for detecting occluded lesions and 79%, 100%, 100%, 99%, and 99%, respectively, for detecting hemodynamically significantly stenotic lesions. Notably, the sensitivity of CDUS for diagnosing significantly stenotic lesions (79%) was lower than that for diagnosing occlusive disease (98%).

CONCLUSIONS

With high sensitivity and accuracy rates, CDUS is a reliable screening method for detecting arterial occlusive disease of the upper extremities. This modality efficiently provides anatomic and hemodynamic data that are useful in cases of such disease.

Diagnosis of peripheral arterial disease: utility of the vascular laboratory

The risks of undiagnosed peripheral arterial disease (PAD) include progressive reduction in quality of life, potential limb loss, and unrecognized comorbid atherosclerotic (concomitant coronary and cerebrovascular) disease. Although a thorough historical review of symptoms and a comprehensive physical examination may lead the clinician to an appropriate index of suspicion, accurate diagnostic testing is crucial. Accredited vascular diagnostic laboratories provide a risk-free description of the presence, severity, and location of PAD. This article describes the basic noninvasive diagnostic tests, criteria for diagnosis, advantages and disadvantages of each diagnostic modality, and a strategy for PAD therapy.

Lower extremity arterial disease. Diagnostic aspects

The prevalence of peripheral arterial disease (PAD) continues to increase, with recent data suggesting that almost 30% of patients in at-risk populations have PAD. Interest in the management of PAD has increased, partly secondary to the technologic advancement of devices and procedures capable of treating a wide array of vascular disorders via endoluminal techniques. A thorough clinical evaluation and accurate noninvasive testing remain the cornerstones of successful patient management and will promote improved outcomes through better patient selection. The utility of physiologic tests for determination of the presence and severity of PAD and more sophisticated imaging studies will allow the cardiovascular specialist to make appropriate decisions about management options. The currently accepted methods for determining the presence of PAD include a historic review of patient symptoms and atherosclerotic risk factors, physical examination, and the appropriate use of noninvasive modalities and X-ray digital subtraction angiography.

Duplex scanning or arteriography for preoperative planning of lower limb revascularisation

OBJECTIVE

to compare the accuracy of duplex and angiography for the planning of lower limb revascularisation.

PATIENTS AND METHODS

Sixty limbs (82% with critical limb ischaemia) were assessed by means of duplex by one surgeon and by angiography by another in terms of the optimum inflow and outflow sites for arterial bypass. These data were then compared with the final operation performed which was used as the gold standard. Surgeons were blinded to the determinations of the other.

RESULTS

surgical plans based on duplex scan and angiography were correct in 77% (40/52) and 79% (41/52), respectively and plans based on the one imaging modality was modified by the other in only 1 and 2 instances. The diagnostic agreement between duplex scanning and arteriography was excellent (Kappa value=0.94, 95% C.I. 0.89-0.98).

CONCLUSIONS

the reliability of duplex scanning is comparable to digital angiography in the preoperative planning of lower extremity arterial reconstruction. However neither exam can be considered as the gold standard because intraoperative arteriography needs to be available in a significant number of infrapopliteal procedures.

Evaluation of patients with peripheral vascular disease

Approximately 10% of people age >55 years have asymptomatic peripheral atherosclerotic disease (PAD), 5% have intermittent claudication (IC, the cardinal symptom), and 1% critical leg ischemia (rest pain or gangrene). In patients with IC, worsening occurs in approximately 16%, bypass surgery is required in approximately 7%, and amputation in approximately 4%. Disease progresses more frequently in diabetics and in tobacco smokers. Patients with PAD suffer increased cardiovascular morbidity related mainly to coronary artery disease with a mortality rate of approximately 30% after 5 years. Compared to patients without PAD, the relative risk of coronary death is approximately 6.6, overall cardiovascular mortality 5.9, and all-cause mortality 3.1. Pain at rest or ischemic gangrene indicates severe, often multilevel arterial occlusive disease and calls for aggressive management, which usually includes angiography and revascularization by percutaneous angioplasty or surgery. Critical limb ischemia results in some 150,000 amputations annually in the U.S., with perioperative mortality rates of 5-10% for below-knee and up to 50% for above-knee amputation because of comorbidities. Physical findings include trophic signs of ischemia, vascular bruits and peripheral pulse deficits. Ischemic ulcers usually involve the tips of the toes or the heel of the foot, and are typically painful on elevation and most bothersome at night. Ancillary diagnostic modalities begin with the ankle/arm systolic pressure index (ABI); a value <0.90 indicates PAD with significant prognostic implications. More precise assessment in the noninvasive vascular laboratory may involve a combination of segmental limb pressure measurements and pulse volume waveform recording, which is over 90% accurate for predicting the level and extent of PAD. Exercise testing enhances the value of these observations. Magnetic resonance imaging methods are emerging to characterize the arterial wall and atherosclerotic lesions. The diagnosis of PAD does not generally require invasive techniques, and most patients with IC do not need contrast angiography. Angiography is indicated for mapping of the extent and location of arterial pathology prior to revascularization.

Early results of infragenicular revascularization based solely on duplex arteriography

PURPOSE

Recent reports have both advocated and questioned the utility of duplex arteriography (DA) as the sole preoperative imaging modality for planning infragenicular revascularization. This study compares the outcome of patients with critical limb ischemia who underwent infragenicular vein grafts on the basis of DA alone versus conventional preoperative contrast arteriography (CA).

METHODS

The study group is composed of 23 consecutive patients who underwent infragenicular vein bypass grafting solely on the basis of preoperative DA from 1998 to 1999. They were compared with 50 consecutive patients who underwent infragenicular vein bypass grafting after CA from 1996 to 1998. Peak systolic velocity and end-diastolic velocity of potential target arteries were recorded during DA studies. In situ saphenous vein grafts were used preferentially, and technical adequacy of all grafts was assessed with completion duplex or arteriography.

RESULTS

DA and CA groups were comparable on the basis of age and risk factors. In one limb (4%), the target artery selected by DA was abandoned because of dense calcification. No other revision in target or inflow artery was required on the basis of intraoperative completion studies. At 1 year, primary graft patency (78% vs 70%, P =.72) and limb salvage (70% vs 81%, P =.21) were comparable between the two groups. In the DA group, mean preoperative target artery peak systolic velocity in patent versus failed grafts was 49 +/- 18 cm/s versus 31 +/- 9 cm/s (P =.04), whereas mean end-diastolic velocity was 22 +/- 7 cm/s versus 14 +/- 8 cm/s (P =.08).

CONCLUSION

Infragenicular revascularization directed by DA alone provides early graft patency and limb salvage rates comparable to similar procedures that are based on CA. Preoperative DA target artery velocities may predict outcome and improve target selection. These initial results justify further clinical testing of DA as the primary imaging modality for planning infragenicular vein grafts.

Can ultrasound replace arteriography in the management of chronic arterial occlusive disease of the lower limb?

OBJECTIVES

to investigate whether colour duplex scanning can be used as the sole diagnostic investigation prior to lower limb revascularisation.

PATIENTS AND METHODS

the results of angiography and duplex were compared in 80 limbs (69 claudication, 11 critical limb ischaemia [CLI]) from 68 patients.

RESULTS

excellent diagnostic agreement (kappa value 0.89, 95% CI 0.85-0.93) was achieved at the femoropopliteal segment. Agreement was good for the aorto-iliac segment (kappa value 0.69, 95% CI 0.61-0.77) and moderate for the infrapopliteal segment (kappa value 0.59, 95% CI 0.55-0.63). Similarly, in the decision-making process excellent agreement was achieved for the femoropopliteal segment (kappa value 0.91, 95% CI 0.88-0.94), good for the aortoiliac segment (kappa value 0.62, 95% CI 0.56-0.68), and moderate for the infrapopliteal segment (kappa value 0.46, 95% CI 0.42-0.50). Duplex detected patent 12 tibial arteries in 10 limbs that were not opacified on arteriography. In four limbs duplex revealed significant disease in the above knee popliteal artery that was missed on arteriography.

CONCLUSIONS

treatment of femoropopliteal disease can be based upon duplex alone in the great majority of cases. However, where there is disease in the aortoiliac segment, or where infrapopliteal revascularisation is long considered both duplex and angiography should be performed to maximise pre-operative information.

Combination of pressure and velocity parameters in the non-invasive diagnosis of aorto-iliac disease

Three different femoral artery flow velocity parameters in combination with segmental pressure measurements were evaluated for their respective diagnostic value in identifying the presence or absence of hemodynamically significant aorto-iliac disease. A total of 60 patients (119 legs) were examined both non-invasively and with arteriography. Doppler flow velocities were recorded using a 5-MHz CW Doppler velocity metering system. Of the three parameters used (peak velocity, decay time and deceleration), a decay time of 220 ms yielded the most practical discriminant value. The accuracy increases when in addition the upper thigh/arm pressure ratio values are considered. The results indicate that the combination of femoral artery decay time with the upper thigh/arm pressure index provides a simple and accurate non-invasive screening method to confirm or rule out aorto-iliac disease. This helps to determine whether the patient is a candidate for arteriography and for potential surgical intervention.

Artificial neural network analysis of common femoral artery Doppler shift signals: classification of proximal disease

The aim of this study was to apply artificial neural networks (ANNs) to the problem of the diagnosis of aorto-iliac arterial disease on the basis of the profile of the common femoral artery (CFA) Doppler flow velocity waveform. The maximum frequency envelopes obtained from the CFA of 180 subjects were used to create sets of training and testing vectors for a back-propagation ANN. The ANN had three outputs: one representing the absence of significant aorto-iliac disease (i.e., < 50% diameter stenosis), one representing the presence of a hemodynamically significant aorto-iliac stenosis (i.e., 50-99% stenosis), and the other representing the presence of an aorto-iliac occlusion. After training, the ANN correctly classified 80% of "no significant disease" testing data, 45% of "significant stenosis" data and 85% of "occlusion" data. This work, thus, demonstrated the ability of an ANN to identify the severity of aorto-iliac disease from the CFA waveform. Although the ANN outperformed standard univariate methods and visual classification of the data, it would appear that further work is needed to increase the accuracy of the ANN to a clinically acceptable standard.

Review of the assessment of single level and multilevel arterial occlusive disease in lower limbs by duplex ultrasound

The purpose of this article is to review the performance of duplex ultrasound scanning in assessing lower limb arterial disease with emphasis on patients with multisegmental occlusive lesions. Several studies have reported that duplex scanning can be as accurate as angiography to localize arterial stenoses. In spite of these promising results, there still remain some difficulties and controversies. Among them, it has been reported that multisegmental disease may affect the accuracy of duplex scanning. Indeed, some studies have indicated a lower sensitivity for detecting significant stenoses distal to severe or total occlusions. It also was demonstrated that second-order stenoses were detected with lower sensitivity compared to first-order stenoses. The main reason proposed to explain this lower sensitivity is that the highly reduced flow distal to occluded or highly stenotic segments increases the difficulty of detecting significant Doppler velocity changes in the distal or secondary stenoses. The intrinsic limitations of the peak systolic velocity ratio used as a classification criterion are presented. Finally, new and promising developments in power Doppler imaging and ultrasound contrast agents are discussed, because they may allow expansion of the capabilities of current ultrasound scanning systems and provide more accurate diagnosis of patients with multiple disease.

Vascular surgery without arteriography: use of Duplex ultrasound

Although contrast arteriography has served as the historical 'gold standard' for diagnosis of arterial disease, recent improvements in noninvasive diagnostic methods have made it possible to plan surgical treatment without subjecting patients to this invasive procedure. This approach avoids both the risks and costs associated with arteriography. Duplex scanning has become the standard noninvasive test for extracranial carotid artery disease, and it can also be used to directly evaluate the lower extremity arteries. In addition to the standard duplex criteria for classification of carotid stenosis, new criteria are available that reflect the stenosis thresholds identified in randomized clinical trials. Clinical experience has clearly shown that carotid endarterectomy can be performed safely based on the duplex scan alone in the majority of patients: however, arteriography is still indicated in selected cases. The evaluation of lower extremity arterial disease requires examination of multiple arterial segments, and most vascular surgeons still rely on the anatomic detail provided by arteriography for preoperative planning. Still, it may be possible to avoid formal preoperative arteriography in selected patients by using a combination of lower extremity duplex scanning and intraoperative arteriography. Further developments in noninvasive testing will continue to reduce the need for diagnostic arteriography prior to direct arterial surgery.

Duplex scanning and effect of multisegmental arterial disease on its accuracy in lower limb arteries

AIM

To assess the accuracy of duplex in assessment of peripheral arterial disease and determine the effect of multisegmental disease on the accuracy duplex as opposed to single lesion.

PATIENTS AND METHODS

One hundred and seventy-seven lower limbs were examined in 90 patients who presented with lower limb arterial disease, (59 male, 31 female, median age 68 years--81 with intermittent claudication, eight rest pain, one ulceration). Patients were examined with duplex US, and arteriography (IA DSA). Two radiologists and two technologists were involved in this double-blind study. Patients were classified into five groups; groups with single stenotic lesions, single occlusions, multiple stenotic lesions or occlusions, and multiple mixed disease. Duplex accuracy was determined in each group.

RESULTS

Duplex was able to differentiate between normal and disease arterial segment with a sensitivity of 92%, specificity 99%, PPV 91%, and NPV 100% and Kappa 0.87. Sixty-six limbs were found to have single lesions, and 68 multisegmental disease. Duplex showed accuracy with a sensitivity of 87%, and specificity of 99%, for single stenotic lesion and 95%, 96% respectively for multisegmental. For single occlusions duplex accuracy showed sensitivity 92% and specificity 100%, and for multisegmental occlusions, sensitivity 97%, and specificity 99%. For mixed multisegmental pathology (stenosis and occlusion), sensitivity 94% and specificity 97%.

CONCLUSION

Duplex is an accurate tool in diagnosis of lower limb arterial disease and multisegmental pathology does not adversely effect this accuracy.

Comparison of duplex imaging and arteriography in the evaluation of lower limb arteries

BACKGROUND

The aim of this study was to assess the accuracy of duplex imaging, compared with arteriography, in detecting arterial disease distal to the renal arteries.

METHODS

Some 177 legs were studied in 90 patients (59 men, 31 women; median age 68 years) with peripheral arterial disease. Each patient had conventional intra-arterial angiography and duplex ultrasonography. Each leg was divided into 17 arterial segments, and the disease in each segment was quantified by measuring the peak systolic velocity ratio across any arterial lesion that was identified.

RESULTS

Compared with angiography, duplex imaging was able to detect arterial disease with an overall sensitivity of 92 per cent, specificity of 99 per cent, positive predictive value 91 per cent and negative predictive value 100 per cent, and with a kappa value of 0.87 (95 per cent confidence interval (c.i.) 0.81-0.93). Duplex was able to determine the length of the arterial lesion with a sensitivity of 89 per cent and a specificity of 98 per cent with a kappa value of 0.88 (95 per cent c.i. 0.86-0.90). When the surgeon's final management decision concerning each vascular lesion was used as the reference, duplex and arteriography were equivalent, with an accuracy of 84 per cent and 85 per cent respectively in identifying the management used.

CONCLUSION

Duplex ultrasonography is reliable in detecting arterial lesions in peripheral arteries and could be used routinely in the initial evaluation of patients with lower limb arterial disease.

Can lower limb ultrasonography replace arteriography?

Although duplex ultrasonography offers a number of theoretical and practical advantages over arteriography for the assessment of lower limb arterial disease, it has not yet been widely accepted into clinical practice. This article reviews the current status of lower limb arterial duplex and concludes that arteriography should no longer be regarded as the diagnostic 'gold-standard' and that duplex ultrasonography should now be the first line investigation in patients with lower limb arterial disease.

In vitro evaluation of multiple arterial stenoses using three-dimensional power Doppler angiography

PURPOSE

The study was done to improve quantification of multiple arterial stenoses and to investigate a new imaging technique for lower limb arteries. Three-dimensional power Doppler angiography was used to quantify in vitro arterial stenoses.

METHODS

We built two types of artery phantoms containing multiple stenoses. One used stenotic porcine arteries, and the other was designed to control the proximal and distal stenoses while we assessed central stenosis of a wall-less agar lumen. Three-dimensional power Doppler angiograms of the flow lumens were generated at different flow rates under steady and pulsatile flow conditions with a PowerPC 8500 computer-based three-dimensional ultrasound imaging system. This experimental system works off-line, performs three-dimensional acquisition, reconstruction, and display of ultrasound images. Images of flow lumens were compared with the measured B-mode images or the true geometry.

RESULTS

This technique produces good three-dimensional angiographic images of the flow lumen, and multiple stenoses do not affect the diagnosis of arterial stenoses. With this technique, the average errors for estimating 80% and 50% area reduction stenoses were -10% and 4%, respectively.

CONCLUSIONS

Three-dimensional power Doppler angiography has the potential to quantitatively grade multisegmental stenoses in lower limbs and generate a map for vasculature surgery planning.

Colour flow duplex imaging of occlusive arterial disease of the lower limb

BACKGROUND

The development of duplex ultrasonography and colour flow imaging has greatly extended the scope of non-invasive assessment of lower limb arterial disease. This review questions whether recent advances might allow colour duplex imaging to displace arteriography as the primary imaging modality for native vessel occlusive disease.

METHODS

A literature review was carried out based predominantly on a Medline database search of English language publications from 1985 to 1996.

RESULTS

Increasing evidence indicates that colour duplex ultrasonography can accurately image the lower limb native arterial tree, and that colour duplex imaging can replace diagnostic arteriography in a large proportion of patients.

CONCLUSION

Arteriography should no longer be considered the gold standard of imaging of peripheral arterial occlusive disease. Future studies should concentrate on the efficacy of colour duplex sonography in guiding clinical decision making.

Duplex sonography of lower extremity arteries

Although indirect noninvasive tests continue to play a role in the evaluation of patients with lower extremity arterial disease, the direct approach of duplex scanning provides both anatomic and physiological information directly from the involved arterial sites. Experience has shown that the results of duplex scanning are comparable with those of arteriography. The addition of color Doppler imaging to standard duplex scanning expedites the examination by helping to identify vessels and localize flow disturbances. However, precise classification of disease severity still requires spectral waveform analysis. Initial screening of patients with duplex scanning can determine the severity of arterial occlusive disease, the location of the lesions, and which interventional techniques are most appropriate. Arteriography can then be reserved for those patients who are being considered for therapeutic interventions. Duplex scanning has become the primary diagnostic test for follow-up of patients after radiological or surgical procedures and should be considered as an essential component of care for patients with infrainguinal bypass grafts. It has also proven to be valuable for intraoperative assessment and the initial evaluation of suspected vascular trauma in the extremities. Finally, new applications such as compression therapy for pseudoaneurysms continue to evolve and expand the role of duplex scanning in the management of patients with vascular problems.

Non-invasive assessment of arterial stenoses in angioplasty surveillance: a comparison with angiography

OBJECTIVES

Comparison of non-invasive arterial measurements with angiography and their use for angioplasty surveillance.

DESIGN

Prospective assessments of arterial stenoses in patients undergoing angioplasty in a 9 month surveillance period.

MATERIALS

Fifty consecutive patients undergoing angioplasty.

METHODS

(i) One hundred and thirty-one sets of clinical assessments, ankle brachial Doppler pressure indices and colour Duplex velocities and diameters were compared to time-matched angiographic diameter stenosis. (ii) Fifty patients undergoing femoropopliteal angioplasty (32 stenoses and 18 occlusions) were studied with ankle branchial Doppler pressure indices and colour Duplex and angiography during a 9 month surveillance period.

RESULTS

(i) Symptoms, pulses, resting ABPI, and exercise ABPI showed no useful correlation with angiography. Duplex velocity ratio and Duplex diameters showed correlation and agreement with angiography respectively. (ii) On surveillance, restenosis was universal but not always clinically significant. Angioplasty caused a rapid improvement in ABPI and imaging studies which worsened at later times. ABPI did not predict clinical failure however, Duplex and angiography predicted all clinical failures.

CONCLUSIONS

Restenosis should be assessed with imaging of the angioplasty site during angioplasty surveillance.

The effect of adjacent segment disease on the accuracy of colour duplex scanning for the diagnosis of lower limb arterial disease

OBJECTIVE

To assess the effect of multisegment disease upon the accuracy of lower limb colour Duplex scanning.

DESIGN

Prospective, semi-blind study.

SETTING

Vascular Laboratory and Radiology Department, University Hospital.

METHODS

A total of 148 limbs (1106 individual arterial segments) were examined from the distal aorta to the origins of the tibial arteries by colour-coded Duplex and arteriography. Individual segments were graded as 0-49%, 50-99% diameter reduced or occluded on the basis of peak systolic velocity ratios < 2.0, > or = 2.0 or an absent Doppler signal, and compared with similarly graded segments from blinded angiographic studies. The agreement (Kappa analysis) between Duplex and arteriography in segments adjacent to at least one proximal or distal > or = 50% diameter reducing lesion was then compared to the agreement between segments free of adjacent disease.

RESULTS

For isolated areas of disease, the kappa value (95% confidence interval) of agreement between Duplex ultrasonography and arteriography was 0.63 (0.53-0.73) and in the presence of neighbouring disease the value was 0.78 (0.73-0.83).

CONCLUSION

We conclude therefore that providing appropriate criteria are used, Duplex assessment of lower limb arterial disease is not adversely affected by adjacent disease.

Summary receiver operating characteristic curves as a technique for meta-analysis of the diagnostic performance of duplex ultrasonography in peripheral arterial disease

RATIONALE AND OBJECTIVES

We summarized and compared the diagnostic performance of duplex and color-guided duplex ultrasonography in the evaluation of peripheral arterial disease. We present our research as an example of the use of summary receiver operating characteristic (ROC) curves in a meta-analysis of diagnostic test data.

METHODS

A search of the English-language medical literature published between 1984 and 1994 retrieved 48 reports, 14 of which met the inclusion criteria. The analysis was limited to the aortoiliac and femoropopliteal segments because only two studies reported results of infrapopliteal arteries. Diagnostic performance of duplex and color-guided duplex, defined as the ability to detect a stenosis of 50-99% or an occlusion, was compared using summary ROC curve methodology. This method takes into account heterogeneity across studies attributable to differences in the threshold values used.

RESULTS

The summary ROC curves demonstrated a high level of diagnostic performance for both types of duplex imaging, with color-guided duplex scanning being superior (p = .022). For example, at a false-positive rate of .05 (specificity = .95), the analysis predicted a true-positive rate (sensitivity) of .83 for duplex alone and .93 for color guided duplex. Differences in the case mix of the study population and study design did not affect the results. Furthermore, sensitivity analysis did not reveal a strong effect of any single study on the results.

CONCLUSION

For aortoiliac and femoropopliteal arteries, the addition of color flow imaging to duplex scanning improves diagnostic performance in evaluating peripheral arterial disease.