Use of colour duplex imaging to diagnose and guide angioplasty of lower limb arterial lesions

Duplex ultrasound scanning of peripheral arterial disease of the lower limb

OBJECTIVES

To assess the reliability and applicability of duplex ultrasound scanning (DUS) of lower limb arteries, compared with digital subtraction angiography (DSA), in patients with peripheral arterial disease (PAD).

DESIGN

A prospective, blinded, comparative study.

MATERIALS AND METHODS

A total of 169 patients were examined by DUS and DSA. Intermittent claudication (IC) was present in 42 (25%) patients and critical limb ischaemia (CLI) in 127 (75%) patients. To allow segment-to-segment comparison, the arterial tree was divided into 15 segments. In total, 2535 segments were examined using kappa (κ) statistics to test the agreement.

RESULTS

The agreement between DUS and DSA was very good (κ>0.8) or good (0.8 ≥ κ>0.6) in most segments, but moderate (0.6 ≥ κ>0.4) in the tibio-peroneal trunk and the peroneal artery. Agreement between the two techniques was significantly better in the supragenicular (κ=0.75 (95% confidence interval (CI): 0.70-0.80)) than in the infragenicular segments (κ=0.63 (0.59-0.67)) (p<0.001). Similarly, the technical success rate was significantly higher in the supragenicular segments (DUS: 100%; DSA: 99%) than in the infragenicular segments (both 93%) (p<0.001). DUS was the best technique for imaging of the distal crural arteries (92% vs. 97%; p<0.001) and DSA was the best technique for imaging of the proximal crural arteries (95% vs. 91%; p<0.01). Neither the agreement nor the technical success rate was influenced by the severity of PAD, that is, IC versus CLI.

CONCLUSION

The agreement between DUS and DSA was generally good, irrespective of the severity of ischaemia. DUS performed better in the supragenicular arteries than in the infragenicular arteries. However, DUS compared favourably with DSA in both tibial vessels, particularly in the distal part, which makes DUS a useful non-invasive alternative to DSA.

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.

Duplex ultrasound-guided femoropopliteal angioplasty: initial and 12-month results from a case controlled study

PURPOSE

To evaluate initial technical success, procedural complications, and 12-month patency of duplex-guided angioplasty compared to conventional fluoroscopically-guided procedures.

METHODS

One hundred four patients (65 men; mean age 69 years) who underwent duplex-guided femoropopliteal angioplasty were compared to 104 patients undergoing fluoroscopically-guide procedures who were matched for age, sex, baseline ankle-brachial index (ABI), and length and grade of lesion. Patients were followed for 12 months, and restenosis was assessed by ABI and duplex sonography.

RESULTS

Technical success was achieved in 88 (84.6%) patients from the duplex-guided group and in 102 (98.1%) control patients (p=0.001). Periprocedural complications occurred in 12.5% (n=13) and 18.3% (n=19), respectively (p=0.4). Contrast-induced transient renal impairment was observed in 7 (6.7%) patients in the fluoroscopic group. One hundred (96.1%) patients in the duplex and 102 (98.1%) patients in the fluoroscopic group completed the 12-month follow-up. Restenosis was found in 35 (39.8%) patients of the duplex group and in 38 (37.2%) patients of the fluoroscopic group (p=0.8).

CONCLUSIONS

Technical success of duplex-guided procedures was significantly lower compared to fluoroscopic angioplasty; complications and 12-month patency were similar with both techniques. Duplex-guided angioplasty may be a feasible alternative, particularly for patients at high risk for contrast-induced complications.

Ultrasound imaging of infrainguinal arterial disease has a high interobserver agreement

OBJECTIVES

to evaluate and compare the operator dependency of duplex ultrasound and digital subtraction arteriography (DSA) in patients suffering from chronic lower limb ischaemia.

DESIGN

prospective and blinded validation study.

MATERIAL

twenty-six consecutive patients (13 male and 13 females) with severe claudication (n=6, 23%), rest pain (n=7, 27%) or tissue loss (n=13, 50%).

METHODS

two physicians independently performed a duplex scan of the lower limb from groin to foot (15 segments). Segments were classified as insignificantly (<50% stenosis) or significantly (>50% stenosis or occlusion) diseased. DSA was performed within 24h of the duplex scanning and was independently reported by two radiologists in the same manner. Interobserver agreement was assessed for both diagnostic methods. After 10 months the arteriograms were reassessed and the intraobserver agreement calculated.

RESULTS

for the limb as a whole the interobserver agreement was good and similar for both duplex and DSA, with kappa-values of 0.79 (95%-CI: 0.72-0.86) and 0.80 (0.74-0.87). In the femoral, crural and pedal segments the interobserver agreement was similar for both methods. The intraobserver agreement between the two DSA readings was 0.84 (0.79-0.90).

CONCLUSION

ultrasound is comparable to arteriography when visualising arterial occlusive disease in patients with chronic lower limb ischaemia.

Ultrasound and fluoroscopic-guided angioplasty over the aortic bifurcation in a patient with previous severe reaction to contrast medium

PURPOSE

To describe a case of ultrasound and fluoroscopic-guided angioplasty necessitated by a patient history of allergic reaction to contrast medium.

CASE REPORT

A 60-year-old man with intermittent right leg claudication had a focal >70% stenosis in the right external iliac artery that was amenable to balloon dilation; however, the patient reported a severe reaction to radiographic contrast medium 10 years previously. Angioplasty was begun with transaortic access to the iliac artery lesion under fluoroscopic guidance only. On-table duplex imaging confirmed the lesion site and reference diameters for balloon selection. The balloon was filled with contrast medium to provide rapid positioning under fluoroscopy. An on-table postangioplasty duplex scan showed improvement in the lumen contour and confirmed a reduction in the peak systolic velocity. At the 1-year follow-up, the patient reports no symptoms referable to the treated segment.

CONCLUSIONS

The combination of ultrasound and fluoroscopy facilitated quick and efficient balloon dilation of an isolated iliac lesion without the use of any contrast medium.

Screening for aortoiliac lesions by visual interpretation of the common femoral Doppler waveform

OBJECTIVE

to study the accuracy of simple visual interpretation of the common femoral artery Doppler waveform for screening the aorto-iliac segment for significant occlusive disease.

DESIGN

prospective and semi-blinded study. Material ninety-four consecutive and elective patients having arteriography due to chronic lower limb ischaemia, presenting symptoms of severe claudication (23%), ischaemic rest pain (34%) or ischaemic skin lesions (43%).

METHODS

one day prior to conventional arteriography a Doppler waveform was obtained in the common femoral artery. Based on visual interpretation, the waveforms were immediately categorised as normal or abnormal. Comparison with single plane arteriography with respect to significant aorto-iliac occlusive disease was undertaken.

RESULTS

visual Doppler waveform interpretation had a sensitivity of 98% (95% CI: 90-100%), a specificity of 81% (CI: 67-90%), a positive predictive value of 86% (CI: 75-93%) and a negative predictive value of 97% (CI: 86-100%) for prediction of significant aorto-iliac occlusive disease using conventional arteriography as the gold standard. The kappa value for the agreement between Doppler waveform interpretation and arteriography was 0.81 (0.68-0.93), representing very good agreement.

CONCLUSION

a normal common femoral Doppler waveform can safely exclude significant upstream aorto-iliac lesions and is a useful timesaving screening tool in the busy vascular laboratory. The method is well tolerated, easy to perform and requires no additional equipment.

Assessment of arterial stenosis in a flow model with power Doppler angiography: accuracy and observations on blood echogenicity

The objective of the project was to study the influence of various hemodynamic and rheologic factors on the accuracy of 3-D power Doppler angiography (PDA) for quantifying the percentage of area reduction of a stenotic artery along its longitudinal axis. The study was performed with a 3-D power Doppler ultrasound (US) imaging system and an in vitro mock flow model containing a simulated artery with a stenosis of 80% area reduction. Measurements were performed under steady and pulsatile flow conditions by circulating, at different flow rates, four types of fluid (porcine whole blood, porcine whole blood with a US contrast agent, porcine blood cell suspension and porcine blood cell suspension with a US contrast agent). A total of 120 measurements were performed. Computational simulations of the fluid dynamics in the vicinity of the axisymmetrical stenosis were performed with finite-element modeling (FEM) to locate and identify the PDA signal loss due to the wall filter of the US instrument. The performance of three segmentation algorithms used to delineate the vessel lumen on the PDA images was assessed and compared. It is shown that the type of fluid flowing in the phantom affects the echoicity of PDA images and the accuracy of the segmentation algorithms. The type of flow (steady or pulsatile) and the flow rate can also influence the PDA image accuracy, whereas the use of US contrast agent has no significant effect. For the conditions that would correspond to a US scan of a common femoral artery (whole blood flowing at a mean pulsatile flow rate of 450 mL min(-1)), the errors in the percentages of area reduction were 4.3 +/- 1.2% before the stenosis, -2.0 +/- 1.0% in the stenosis, 11.5 +/- 3.1% in the recirculation zone, and 2.8 +/- 1.7% after the stenosis, respectively. Based on the simulated blood flow patterns obtained with FEM, the lower accuracy in the recirculation zone can be attributed to the effect of the wall filter that removes low flow velocities. In conclusion, the small errors reported in vitro may support the clinical use of this technique.

Color doppler ultrasonography imaging to guide transluminal angioplasty of venous stenosis

BACKGROUND

The objective of access surveillance is the early recognition of dysfunction in order to be able to correct the stenosis by angioplasty or surgery before access thrombosis occurs. The advent of color Doppler imaging has enabled studies of color Doppler ultrasonography (CDU) for the guidance of percutaneous transluminal angioplasty (PTA). The aim of the present study was to investigate whether color Doppler imaging alone can be safely and effectively used to diagnose vascular graft access stenoses and guide subsequent PTA.

METHODS

Using the ultrasound velocity dilution method, we measured access blood flow (Qa) during the first hour of hemodialysis every month in patients with grafts as vascular access. When the decrease in Qa from the baseline value was 40% or more, CDU was performed and immediately followed by PTA in the presence of a stenosis of more than 50%. The Qa was then measured during the first dialysis after PTA and one month later. Repeated-measure analysis of variance was applied to evaluate the early and late (after one month) effect of PTA.

RESULTS

Twelve PTAs were performed under CDU guidance in nine patients and led to the elimination of the stenosis or its reduction (two cases). The mean Qa was 809 +/- 263 mL/min at baseline, 468 +/- 153 before PTA, and 820 +/- 281 after PTA. The difference between the pre-PTA and post-PTA values was highly significant (P < 0.001), and the mean value after PTA was not different from baseline (P = 0.672). There were no relevant complications directly related to the procedure.

CONCLUSIONS

The CDU procedure is effective for the diagnosis of vascular access stenosis and as a guide during the PTA procedure. It could improve stenosis screening by avoiding the risks of exposure to ionizing radiation and of adverse reactions to contrast media.