Peripheral arterial disease: comparison of color duplex US and contrast-enhanced MR angiography for diagnosis

Improving image quality consistency and diagnostic accuracy in lower extremity CT angiography using a split-bolus contrast injection protocol

OBJECTIVES

To evaluate the clinical value of using a split-bolus contrast injection protocol in improving image quality consistency and diagnostic accuracy in lower extremity CT angiography (CTA).

METHODS

Fifty (mean age, 66 ± 12 years) and 39 (mean age, 66 ± 11 years) patients underwent CTA in the lower extremity arteries using split-bolus and fixed-bolus injection schemes, respectively. The objective and subjective image quality of the 2 groups were compared and the diagnostic efficacy for the degree of vessel stenosis was compared using digital subtraction angiography as the gold standard. A P < .05 was considered statistically significant.

RESULTS

In comparison with the fixed-bolus scheme, the split-bolus scheme greatly improved the consistency of image quality of the low extremities by significantly increasing the arterial enhancement (337.87 ± 64.67HU vs. 254.74 ± 71.58HU, P < .001), signal-to-noise ratio (22.58 ± 11.64 vs. 7.14 ± 1.98, P < .001), and contrast-to-noise ratio (37.21 ± 10.46 vs. 31.10 ± 15.40, P = .041) in the infrapopliteal segment. The subjective image quality was better (P < .001) and the diagnostic accuracy was higher in the split-bolus group than in the fixed-bolus group (96.00% vs. 91.67%, P < .05, for diagnosing >50% stenosis, and 97.00% vs. 89.10%, P < .05, for diagnosing occlusion) for the infrapopliteal segment arteries.

CONCLUSIONS

Compared with the fixed-bolus injection scheme, the split-bolus injection scheme improves the image quality consistency and diagnostic accuracy especially for the infrapopliteal segment arteries in lower extremity CTA.

ADVANCES IN KNOWLEDGE

(1) The split-bolus injection scheme of CTA of the lower extremity arteries improves the overall image quality, uniformity of contrast enhancement. (2) Compared with the fixed-bolus injection scheme, the split-bolus injection scheme especially improves the infrapopliteal segment arteries image quality and diagnostic efficacy.

ACR Appropriateness Criteria® Sudden Onset of Cold, Painful Leg: 2023 Update

Acute onset of a cold, painful leg, also known as acute limb ischemia, describes the sudden loss of perfusion to the lower extremity and carries significant risk of morbidity and mortality. Acute limb ischemia requires rapid identification and the management of suspected vascular compromise and is inherently driven by clinical considerations. The objectives of initial imaging include confirmation of diagnosis, identifying the location and extent of vascular occlusion, and preprocedural/presurgical planning. The American College of Radiology 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.

Gadofosveset-Trinatrium-Enhanced MR Angiography and MR Venography in the Diagnosis of Venous Thromboembolic Disease: A Single-Center Cohort Study

BACKGROUND

The aim of this single-center combined prospective/retrospective cohort study was to analyze Gadolinium (Gd)-enhanced MRA (magnetic resonance angiography) and MRV (MR venography) for the diagnosis of pulmonary artery embolism and deep venous thrombosis. The gold standard methods result in major exposure to radiation and a high amount of nephrotoxic iodinated contrast media. This is the first larger contrast-enhanced MR imaging study of acute and chronic venous thromboembolic disease of various stages.

METHODS

We prospectively examined 88 patients presenting clinical signs of deep vein thrombosis and/or pulmonary artery embolism. A single-session, one-stop shop Gd-enhanced MRA/MRV at 1.5 Tesla, using gradient echo sequences with very short repetition and echo times as well as low flip angles with subtraction and three-dimensional reconstruction, was performed. A diagnosis was made with the consensus of two experienced radiologists.

RESULTS

We observed excellent MRA image quality in 87% and even higher diagnostic image quality of MRV in 90% of our examinations. Pulmonary artery embolism occurred with deep vein thrombosis in 22%.

CONCLUSIONS

Gd-enhanced MRA/MRV provided excellent image quality for the diagnosis of venous thromboembolic disease in the majority of cases. It may be particularly useful to plan and follow-up filter implantation and retrieval in the inferior caval vein.

Influence of diabetes on diagnostic performance of computed tomography angiography of the calf arteries in acute limb ischemia

BACKGROUND

Patients with diabetes mellitus (DM) have a more extensive distal arterial occlusive disease compared to non-diabetic patients. Diagnostic imaging is a necessity to identify the location and extent of the arterial occlusion in acute limb ischemia (ALI). Computed tomography angiography (CTA) is the most commonly used modality and the diagnostic performance with CTA of calf arteries may be questioned.

PURPOSE

To evaluate diagnostic performance of CTA of calf arteries in ALI and to compare patients with and without DM.

MATERIAL AND METHODS

All thrombolytic treatments performed during 2001-2018 in patients with ALI were included. Initial digital subtraction angiography (DSA) and CTA of all patients were classified according to the Inter-Society Consensus for the Management of Peripheral Arterial Disease (TASC II) below-the-knee arteries and compared to CTA. Two raters assessed the CTA images independently. Inter-rater reliability was expressed as intraclass correlation (ICC) with 95% confidence intervals (CI).

RESULTS

Patients with (n = 23) and without (n = 85) DM had lower (P = 0.006) glomerular filtration rate. ICC between CTA and DSA was 0.33 (95% CI -0.22 to 0.56) and 0.71 (95% CI 0.38-0.68) in patients with and without DM, respectively. Sensitivity with CTA for TASC D lesions in patients with and without DM was 0.14 (95% CI -0.12 to 0.40) and 0.64 (95% CI 0.48-0.80), respectively.

CONCLUSION

The sensitivity of CTA for assessment of infra-popliteal TASC D lesions in patients with ALI was not acceptable in patients with DM in contrast to those without DM. Another imaging option at present times should be considered for patients with DM.

Functional Popliteal Artery Entrapment Syndrome: An Approach to Diagnosis and Management

Popliteal Artery Entrapment Syndrome (PAES) is an uncommon syndrome that predominantly affects young athletes. Functional PAES is a subtype of PAES without anatomic entrapment of the popliteal artery. Patients with functional PAES tend to be younger and more active than typical PAES patients. A number of differential diagnoses exist, the most common of which is chronic exertional compartment syndrome. There is no consensus regarding choice of investigation for these patients. However, exercise ankle-brachial indices and magnetic resonance imaging are less invasive alternatives to digital subtraction angiography. Patients with typical symptoms that are severe and repetitive should be considered for intervention. Surgical intervention consists of release of the popliteal artery, either via a posterior or medial approach. The Turnipseed procedure involves a medial approach with a concomitant release of the medial gastrocnemius and soleal fascia, the medial tibial attachments of the soleus and excision of the proximal third of the plantaris muscle. Injection of botulinum A toxin under electromyographic guidance has recently shown promise as a diagnostic and/or therapeutic intervention in small case series. This review provides relevant information for the clinician investigating and managing patients with functional PAES.

Peripheral artery disease: the new frontiers of imaging techniques to evaluate the evolution of regenerative medicine

Introduction: Stem cells (ESC, iPSC, MSC) are known to have intrinsic regenerative properties. In the last decades numerous findings have favored the development of innovative therapeutic protocols based on the use of stem cells (Regenerative Medicine/Cell Therapy) for the treatment of numerous diseases including PAD, with promising results in preclinical studies. So far, several clinical studies have shown a general improvement of the patient's clinical outcome, however they possess many critical issues caused by the non-randomized design of the limited number of patients examined, the type cells to be used, their dosage, the short duration of treatment and also their delivery strategy. Areas covered: In this context, the use of the most advanced molecular imaging techniques will allow the visualization of very important physio-pathological processes otherwise invisible with conventional techniques, such as angiogenesis, also providing important structural and functional data. Expert opinion: The new frontier of cell therapy applied to PAD, potentially able to stop or even the process that causes the disease, with particular emphasis on the clinical aspects that different types of cells involve and on the use of more innovative molecular imaging techniques now available.

Reasonable Glycemic Control Would Help Wound Healing During the Treatment of Diabetic Foot Ulcers

INTRODUCTION

The effect of glycemic control on wound healing in patients with diabetic foot ulcers (DFUs) is inconsistent among different studies. This study was performed to investigate the association between level of hemoglobin A1c (HbA1c) at baseline as well as during treatment and wound healing and mortality in patients with DFU.

METHODS

Hospitalized DFU patients were recruited consecutively with their basic clinical data collected and treated according to clinical practice guidelines. These patients were followed-up for 1 year to observe the outcomes, including ulcer healing and death. The associations between baseline HbA1c level or mean HbA1c level during treatment and wound healing as well as mortality were evaluated in univariate and multivariate logistic regression models.

RESULTS

By the end of the follow-up, 40 (13.4%) patients had died. A total of 168 (65.1%) patients achieved ulcer healing in the remaining 258 living participants. Baseline HbA1c was not associated with ulcer healing in unadjusted or adjusted models (P > 0.05). The wound healing rate was higher (OR 2.01, 95% CI 1.02-3.96, P < 0.05) after adjustment when HbA1c was controlled between 7.0% and 8.0% during treatment compared to HbA1c controlled at less than 7.0%. This probability of ulcer healing increased to 3 (OR = 3.01, 95% CI 1.32-6.86, P = 0.01) after adjustment in the subgroup with baseline HbA1c no more than 8.0%. Neither baseline HbA1c nor mean HbA1c during treatment presented any correlation with 1-year death rate.

CONCLUSION

A reasonable HbA1c target, a range between 7.0% and 8.0% during treatment, could facilitate ulcer healing without increase of mortality in patients with DFU, especially for those with better glycemic control at admission.

Improving the diagnosis of peripheral arterial disease in below-the-knee arteries by adding time-resolved CT scan series to conventional run-off CT angiography. First experience with a 256-slice CT scanner

PURPOSE

Run-off Computed Tomography Angiography (run-off CTA) of the lower extremities has become the method of choice for the diagnostic imaging of patients suffering from peripheral arterial disease (PAD). However, it remains a challenging radiological examination with a considerable risk of non-diagnostic image quality for the assessment of below-the-knee arteries. In this study, we investigate the diagnostic benefit of adding time-resolved CT scan series to the standard run-off CTA by performing repeated axial acquisitions over the calves of the patient during a second bolus of iodinated contrast injection.

MATERIALS AND METHODS

This prospective study included 20 patients (9 male, 11 female; mean age 66.1 ± 14.9 years) who received a standard run-off CTA and an additional time-resolved CT scan series after a 10 min delay. The time-resolved series consisted of 18 repeated axial acquisitions over the calves directly below the knee with a 2 s interphase delay. For both series, two observers independently assessed the anterior tibial, posterior tibial and peroneal arteries of both legs for following criteria: arterial enhancement, presence and degree of stenosis, the confidence of grading, degree of stenosis and venous overlay. Quantitative assessment of arterial enhancement was performed by measuring the mean CT values (HU) in all arteries. Radiation exposure was quantified by the effective dose.

RESULTS

A total of 118 arteries were assessed. The observer study showed that the additional time-resolved series improved both arterial enhancement (64% considered optimal enhanced versus 44%) and diagnostic confidence (59% considered as certain versus 33%) for the assessment of arterial stenosis (all p < 0.05). Venous overlay reduced from 15% to 6%. In all three arteries, the measured contrast enhancement by CT values (HU) was considerably higher (average 48%, p <  0.05) with the time-resolved series. The time-resolved series had an effect on stenosis classification (p = 0.03): a higher number of arteries were graded as having a non-significant stenosis (78.8% versus 71.2%). The interobserver variability in stenosis classification improved from κ = 0.39 to κ = 0.61. The mean effective dose was 5.1 ± 1.3 mSv for the run-off CTA and 0.2 ± 0.07 mSv for the time-resolved series. Per patient, a total volume of 140 mL contrast agent was injected.

CONCLUSION

A dynamic CT scan protocol with repeated axial series can be added to a standard helical run-off CTA sequence for the lower extremities within the same CT examination, and it increases image quality and diagnostic confidence for the assessment of presence and degree of arterial stenosis in below-the-knee arteries.

Comparison of leg loader and treadmill exercise for evaluating patients with peripheral artery disease

The exercise ankle-brachial index (ABI) helps diagnose lower extremity peripheral artery disease (PAD). Patients with comorbidities may be unable to perform treadmill exercise, the most common stress loading test. While the active pedal plantar flexion (APP) test using the leg loader, simple and easy stress loading device, could be an alternative, there are no data comparing the leg loader and treadmill exercise. Therefore, we aimed to compare APP using the leg loader and treadmill exercise to evaluate PAD. A total of 27 patients (54 limbs) diagnosed with PAD with intermittent claudication and considered for angiography and/or endovascular treatment were recruited prospectively, and both the leg loader and treadmill were performed. There was a strong correlation (r = 0.925, p < 0.001) between the leg loader ABI and treadmill ABI; however, the decrease rate of the leg loader ABI was significantly less than that of treadmill ABI (14.0% [5.6, 30.1] vs. 25.8% [6.1, 53.1], p < 0.001). The number of patients who terminated the exercise prematurely due to dyspnea was four during the treadmill and zero during the leg loader. There was a good correlation between the leg loader ABI and treadmill ABI. Although leg loader, a simple, safe, and easy method, could be an alternative to diagnose PAD, further studies are needed to evaluate the diagnostic value of the leg loader in patients with borderline ABI or those unable to perform the treadmill.

Contrast-enhanced ultrasonography in chronic glomerulonephritides: correlation with histological parameters of disease activity

PURPOSE

To compare contrast-enhanced ultrasonography (CEUS)-derived time-intensity (TI) curves with histological findings in kidneys of patients affected by chronic glomerulonephritides (GN) in the early stage of disease.

METHODS

Research ethics committee approval and patient written informed consent were obtained. Thirty-one patients who showed clinical and laboratory signs of GN, with preserved renal function, were consecutively enrolled. They underwent kidney CEUS, from which TI curves were obtained, and kidney biopsy. TI curves were compared with clinical data, ultrasound (US) Doppler, and histological parameters.

RESULTS

The persistence of contrast agent signal during the wash-out phase was found to be correlated with the degree of disease activity (p = 0.016) and in particular with the presence of mesangial hyperplasia (p = 0.008). No correlation was observed between TI curves and clinical or Doppler US-derived parameters.

CONCLUSIONS

The persistence of contrast agent signal in the wash-out phase of CEUS appears to reflect a disturbance of perfusion in glomerular capillaries in the early stages of GN. We found that the histological element directly correlated with the prolonged wash-out was mesangial hyperplasia.

CT Angiography of Peripheral Arterial Disease by 256-Slice Scanner: Accuracy, Advantages and Disadvantages Compared to Digital Subtraction Angiography

BACKGROUND

Peripheral arterial occlusive disease (PAOD) may cause disabling claudication or critical limb ischemia. Multidetector computed tomography (CT) technology has evolved to the level of 256-slice CT scanners which has significantly improved the spatial and temporal resolution of the images. This has provided the capability of chasing the contrast bolus at a fast speed enabling angiographic imaging of long segments of the body. These images can be reconstructed in various planes and various modes for detailed analysis of the peripheral vascular diseases which helps in making treatment decision.

PURPOSE

The aim of this retrospective study was to compare the CT angiograms (CTAs) of all cases of PAOD done by 256-slice CT scanner at a tertiary care vascular center and comparing these images with the digital subtraction angiograms (DSAs) of these patients.

MATERIALS AND METHODS

The retrospective study included 53 patients who underwent both CTA and DSA at our center over a period of 3 years from March 2013 to March 2016.

RESULTS

The CTA showed high sensitivity (93%) and specificity (92.7%) for overall assessment of degree of stenosis in a vascular segment in cases of aortic and lower limb occlusive disease. The assessment of lesions of infrapopliteal segment was comparatively inferior (sensitivity 91.6%, accuracy 73.3%, and positive predictive value 78.5%), more so in the presence of significant calcification. The advantages of CTA were its noninvasive nature, ability to image large area of body, almost no adverse effects to the patients, and better assessment of vessel wall disease. However, the CTA assessment of collaterals was inferior with a sensitivity of only 62.7% as compared to DSA. Overall, 256-slice CTA provides fast and accurate imaging of vascular tree which can restrict DSA only in few selected cases as a problem-solving tool where clinico-radiological mismatch is present.

Duplex Sonography versus Angiography for Assessment of Femoropopliteal Arterial Disease in a “Real-World” Setting

Purpose:

To evaluate the agreement of duplex ultrasound (DUS) versus digital subtraction angiography (DSA) for assessment of femoropopliteal arterial disease in a real-world clinical setting.

Methods:

Consecutive patients with peripheral artery disease who were scheduled for a percutaneous intervention were included in this retrospective study. During an 18-month period, 491 patients (276 men; median age 73 years, interquartile range 64–81) were enrolled. A peak systolic velocity ratio (PSVR) >2.4 was the optimal cutoff for detecting a >50% stenosis by DSA. Findings of preprocedural DUS in the proximal, middle, and distal ipsilateral superficial femoral artery and in the popliteal segment were analyzed for agreement with preprocedural femoropopliteal DSA using kappa statistics. Only the target limb in each patient was analyzed, for a total of 1964 vascular segments.

Results:

Agreement for the degree of stenosis in 10% increments was only moderate (weighted kappa 0.67, 95% CI 0.65 to 0.69). Using the PSVR >2.4 cutoff, agreement between DUS and DSA for a >50% stenosis was good (kappa 0.79, 95% CI 0.77 to 0.81). Sensitivity, specificity, positive predictive value, and negative predictive value for correctly detecting a >50% stenosis by DUS were 0.81 (0.78 to 0.84), 0.93 (0.91 to 0.94), 0.84 (0.81 to 0.87), and 0.91 (0.87 to 0.95), respectively. Comparable findings were observed within different patient subgroups.

Conclusion:

Agreement between DUS and DSA in the femoropopliteal segment is only moderate with respect to the absolute degree of stenosis. However, detection of a >50% stenosis can be done with acceptable precision in routine clinical practice using PSVR >2.4 as a threshold.

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.

Long-Term Prognostic Risk in Lower Extremity Peripheral Arterial Disease as a Function of the Number of Peripheral Arterial Lesions

Background

Although patients with peripheral artery disease (PAD) are known to have an increased risk of adverse prognosis, simple techniques to further risk‐stratify PAD patients would be clinically useful. A plausible but unexplored factor to predict such risk would be greater disease burden, manifested as multiple lower extremity lesions. The aim of this study was to examine the association between having multiple versus isolated lower extremity PAD lesions and long‐term prognosis.

Methods and Results

A prospective cohort of 756 newly diagnosed PAD patients underwent duplex ultrasound testing to determine the number of lower extremity lesions. Cox regression models examined the independent association of lesion number (≥3 and 2 versus 1) and adverse prognosis (defined as a composite end point comprising first occurrence of either lower extremity amputation, admission for heart failure, nonfatal stroke, myocardial infarction, or unstable angina or mortality), adjusting for demographic and clinical risk factors. Analyses were replicated using an advanced Cox‐based model for multiple events. A total of 173 patients (23%) had ≥3 lesions, 197 (26%) had 2 lesions, and 386 (51%) had 1 lesion. After a median follow‐up of 3.2 years, patients with ≥3 lesions had an increased risk of experiencing a first adverse event (adjusted hazard ratio 1.60, 95% CI 1.08–2.38, P=0.020) and an increased risk of having multiple events (adjusted hazard ratio 1.53, 95% CI 1.08–2.18, P=0.018). Patients with 2 lesions had a prognosis similar to those with 1 lesion.

Conclusions

Among PAD patients, a greater number of lesions is associated with an increased risk of an adverse prognosis over 3 years of follow‐up. Assessing the number of lower extremity lesions might serve as a simple risk‐stratification tool at initial PAD diagnosis.

Gadolinium Enhanced MR-angiography Results in Patients With Peripheral Arterial Disease: Positive Predictive Value Compared to Surgery

Background:

Peripheral arterial disease (PAD) represents systematic atherosclerosis of great vessels. PAD affects approximately 10-20 % of patients older than 60 years and is associated with high mortality and morbidity rate debilitating individuals’ life.

Objectives:

To compare the results of Gadolinium enhanced MR-Angiography and surgery in patients suspected to have peripheral arterial disease.

Materials and Methods:

In this prospective cohort study, 30 consecutive patients matching the inclusion criteria were enrolled and MR-Angiography was performed prior to surgery for each one.

Results:

22 patients were male (73.3%) and the mean age was 60.3 ± 10.6 years in our study group. The most common artery for cut off and run off was superior femoral artery in both assessments. Proximal section of each artery was the most common anatomical section for cut off and run off. There was a same report of cut off artery by MR-Angiography and surgery (kappa coefficient of agreement was 0.96, P value < 0.001) and positive predictive value was 0.97 (95% CI: 0.83-0.99).

Conclusions:

According to our findings MR-angiography is an appropriate alternative imaging modality for patients suspected to have peripheral arterial disease and it facilitates the early diagnosis proposed by the clinical findings. Also beneficial characteristics of this method such as low exposure to ionizing radiation, repeatability, and low risk of contrast agent-induced nephropathy make it a modality of choice in patients with renal impairment.

Imaging techniques to evaluate cell therapy in peripheral artery disease: state of the art and clinical trials

Cell-based therapies, as potential approach to cure peripheral artery disease (PAD), have been clinically investigated after promising results in preclinical models. The so far published studies are very heterogeneous, as different cell sources, cell types, amounts of administered cells and delivering strategies have been used. Overall, cell therapies for PAD bring about a general improvement of patient's clinical condition, even though conclusions cannot be established due to the small size and non-randomized design of these trials. In this context, non-invasive imaging techniques, aimed to monitor angiogenesis and neovascularization after cell therapy, will help the follow-up of clinical studies. However, still much work is needed to establish advanced imaging procedure to overcome the limitation of the current techniques and to accumulate more data in large populations of patients. Here, we report the main imaging techniques employed to evaluate the outcome of the different cell-based therapies in PAD. Moreover, we focus on both published and ongoing clinical trials utilizing cell therapy in PAD.

4-French-compatible endovascular material is safe and effective in the treatment of femoropopliteal occlusive disease: results of the 4-EVER trial

PURPOSE

To report the 1-year results of a prospective multicenter trial to evaluate the safety and efficacy of treating symptomatic femoropopliteal occlusive disease using 4-F-compatible materials and no closure device.

METHODS

The non-randomized 4-EVER trial (4-F endovascular treatment approach to infrainguinal disease) was conducted at 5 European hospitals (ClinicalTrials.gov identifier NCT01413139). The protocol mandated the use of only 4-F sheaths, self-expanding nitinol stents (Astron Pulsar or Pulsar-18 stent), and balloons from a single manufacturer. Between June 2010 and June 2011, 120 symptomatic patients (82 men; mean age 71±9.7 years, range 47-90), primarily claudicants, treated for 120 femoropopliteal lesions (>90% TASC A/B) were enrolled. The mean lesion length was 71.0±45.9 mm. Follow-up evaluations were scheduled on day 1 and at 1, 6, 12, and 24 months. A duplex ultrasound was performed on all follow-up visits to determine vessel patency (primary outcome measure at 1 year), and biplanar radiography was performed at 12 and 24 months to assess stent fracture.

RESULTS

Stents were successfully implanted in all patients: an Astron Pulsar stent in 70 (58.3%) lesions and a Pulsar-18 stent in 46 (38.3%); 4 (3.3%) patients had both stents implanted for flow-limiting dissection after predilation. No closure devices were used; the mean manual compression time was 8.1 minutes (2-15). Four (3.3%) patients developed significant hematoma at the puncture site, but none required surgical repair. The overall 12-month primary patency rate was 81.4%: 85.2% for the Astron Pulsar and 73.4% for the Pulsar-18 (p=0.236). Freedom from target lesion revascularization at 12 months for the entire cohort was 89.3%.

CONCLUSION

Compared to published historical data for superficial femoral artery type A/B lesion stenting using 6-F devices, the 4-F devices applied in this trial showed similar patency at 12 months, fewer access site complications, and shorter manual compression times, supporting the supposition that 4-F endovascular treatment is safe and effective.

Functional MRI in peripheral arterial disease: arterial peak flow versus ankle-brachial index

Objectives

The purpose of this study was to compare the success rate of successful arterial peak flow (APF) and ankle-brachial index (ABI) measurements in patients with suspected or known peripheral arterial disease (PAD).

Materials and Methods

183 patients with varying degrees of PAD were included. All subjects underwent ABI measurements and MR imaging of the popliteal artery to determine APF. Proportions of patients with successful APF and ABI measurements were compared and the discriminative capability was evaluated.

Results

APF was successfully measured in 91% of the patients, whereas the ABI could be determined in 71% of the patients (p<0.01). Success rates of APF and ABI were significantly higher in patients with intermittent claudication (95% and 80%, respectively) than in patients with critical ischemia (87% and 62%, respectively).

Conclusions

Compared to the assessment of PAD severity with ABI, the success rate of MRI-based APF measurements in patients with a clinical indication for MRA is 20% higher, with similar discriminatory capacity for disease severity. Therefore, APF is an especially convenient and valuable measure to assess severity in PAD patients scheduled to undergo MR angiography to obtain additional functional information concerning the vascular status.

Mechanical thrombectomy using Rotarex system and stent-in-stent placement for treatment of distal femoral artery occlusion secondary to stent fracture - a case report and literature review

Background:

Treatment of peripheral arterial diseases may be distinguished into conservative and interventional management; the latter is divided into surgical and endovascular procedures. Management of peripheral artery stenosis and occlusion with vascular stents is associated with the risk of late complications such as restenosis, stent fracture or dislocation.

Case Report:

A 62-year-old woman with generalized atherosclerosis, particularly extensive in lower limb arteries, was admitted to the Department of Angiology 11 months after having an endovascular procedure performed due to critical ischemia of left lower limb. Because of stent occlusion, a decision to perform angiographic examination of lower limb arteries was made. Examination revealed occlusion of the superficial femoral artery along its entire length, including previously implanted stents. Distal stent was fractured with slight dislocation of the proximal segment. A decision was made to perform mechanical thrombectomy using a Rotarex system followed by a stent-in-stent placement procedure. Follow-up angiography and ultrasound scan performed 24 hours after the procedure revealed a patent vessel with satisfactory blood flow.

Discussion:

Nowadays, imaging diagnostics of peripheral artery stenosis involves non-invasive examinations such as ultrasound, minimally invasive examinations such as angio-MRI and MDCT, or invasive examinations such as DSA and IVUS. DSA examinations are used to confirm significant stenosis or occlusion of a vessel, particularly when qualifying a patient for endovascular treatment. Due to their anatomic location, the superficial femoral artery and the popliteal artery are subject to various forces e.g. those exerted by the working muscles. Mechanical thrombectomy and atherectomy are efficient methods of arterial recanalization used in the treatment of acute, subacute or even chronic occlusions or stenosis of peripheral vessels.

Conclusions:

Frequency of angioplasty and vascular stent implantation procedures is increased in patients with peripheral arterial disease, thus increasing the incidence of reported early and late complications such as acute stent thrombosis, restenosis and stent fractures. The Rotarex transcutaneous mechanical thrombectomy system is an efficient method of treating occlusions in arterial stents. It is also safe when performed by experienced operators.

Current imaging modalities for atherosclerosis

Atherosclerotic disease is responsible for nearly half of all deaths in the western world. During the past three decades, considerable efforts have been made towards detection and assessment of atherosclerosis plaques in various vascular beds using different imaging techniques. Recently, both noninvasive and invasive modalities have frequently been used to refine cardiovascular risk assessment in high-risk individuals, to evaluate the natural history of atheroma burden and to reveal the impact of anti-atherosclerotic medical therapies on disease progression. In this review, we provide an overview of the currently available imaging modalities. This article will underscore arterial wall imaging to assess the impact of medical therapies on atherosclerosis and to develop the effective therapeutic strategies, resulting in the prevention of cardiovascular complications.

Dynamic contrast-enhanced MRI assessment of hyperemic fractional microvascular blood plasma volume in peripheral arterial disease: initial findings

Objectives

The aim of the current study was to describe a method that assesses the hyperemic microvascular blood plasma volume of the calf musculature. The reversibly albumin binding contrast agent gadofosveset was used in dynamic contrast-enhanced magnetic resonance imaging (DCE MRI) to assess the microvascular status in patients with peripheral arterial disease (PAD) and healthy controls. In addition, the reproducibility of this method in healthy controls was determined.

Materials and Methods

Ten PAD patients with intermittent claudication and 10 healthy control subjects were included. Patients underwent contrast-enhanced MR angiography of the peripheral arteries, followed by one DCE MRI examination of the musculature of the calf. Healthy control subjects were examined twice on different days to determine normative values and the interreader and interscan reproducibility of the technique. The MRI protocol comprised dynamic imaging of contrast agent wash-in under reactive hyperemia conditions of the calf musculature. Using pharmacokinetic modeling the hyperemic fractional microvascular blood plasma volume (V_p, unit: %) of the anterior tibial, gastrocnemius and soleus muscles was calculated.

Results

V_p was significantly lower for all muscle groups in PAD patients (4.3±1.6%, 5.0±3.3% and 6.1±3.6% for anterior tibial, gastrocnemius and soleus muscles, respectively) compared to healthy control subjects (9.1±2.0%, 8.9±1.9% and 9.3±2.1%). Differences in V_p between muscle groups were not significant. The coefficient of variation of V_p varied from 10–14% and 11–16% at interscan and interreader level, respectively.

Conclusions

Using DCE MRI after contrast-enhanced MR angiography with gadofosveset enables reproducible assessment of hyperemic fractional microvascular blood plasma volume of the calf musculature. V_p was lower in PAD patients than in healthy controls, which reflects a promising functional (hemodynamic) biomarker for the microvascular impairment of macrovascular lesions.

MRI of arterial flow reserve in patients with intermittent claudication: feasibility and initial experience

Objectives

The aim of this work was to develop a MRI method to determine arterial flow reserve in patients with intermittent claudication and to investigate whether this method can discriminate between patients and healthy control subjects.

Methods

Ten consecutive patients with intermittent claudication and 10 healthy control subjects were included. All subjects underwent vector cardiography triggered quantitative 2D cine MR phase-contrast imaging to obtain flow waveforms of the popliteal artery at rest and during reactive hyperemia. Resting flow, maximum hyperemic flow and absolute flow reserve were determined and compared between the two groups by two independent MRI readers. Also, interreader reproducibility of flow measures was reported.

Results

Resting flow was lower in patients compared to controls (4.9±1.6 and 11.1±3.2 mL/s in patients and controls, respectively (p<0.01)). Maximum hyperemic flow was 7.3±2.9 and 16.4±3.2 mL/s (p<0.01) and the absolute flow reserve was 2.4±1.6 and 5.3±1.3 mL/s (p<0.01), respectively in patients and controls. The interreader coefficient of variation was below 10% for all measures in both patients and controls.

Conclusions

Quantitative 2D MR cine phase-contrast imaging is a promising method to determine flow reserve measures in patients with peripheral arterial disease and can be helpful to discriminate patients with intermittent claudication from healthy controls.

Diagnostic approach to peripheral arterial disease

This article discusses diagnostic imaging techniques used in the evaluation and management of patients with peripheral arterial disease (PAD). Along with a complete vascular examination, noninvasive physiologic testing is used for the initial evaluation of patients with suspected PAD. Duplex ultrasonography provides information on the degree of stenosis or occlusion within a vessel and allows assessment of the vessel wall and plaque morphology. Angiographic imaging techniques should be reserved for determining the optimal endovascular or surgical approach for patients requiring revascularization. Together, all available diagnostic modalities contribute to successful evaluation and management of patients with PAD.

Magnetic resonance imaging in peripheral arterial disease: reproducibility of the assessment of morphological and functional vascular status

OBJECTIVES

The aim of the current study was to test the reproducibility of different quantitative magnetic resonance imaging (MRI) methods to assess the morphologic and functional peripheral vascular status and vascular adaptations over time in patients with peripheral arterial disease (PAD).

MATERIALS AND METHODS

Ten patients with proven PAD (intermittent claudication) and arterial collateral formation within the upper leg and 10 healthy volunteers were included. All subjects underwent 2 identical MR examinations of the lower extremities on a clinical 1.5-T MR system, with a time interval of at least 3 days. The MR protocol consisted of 3D contrast-enhanced MR angiography to quantify the number of arteries and artery diameters of the upper leg, 2D cine MR phase contrast angiography flow measurements in the popliteal artery, dynamic contrast-enhanced (DCE) perfusion imaging to determine the influx constant and area under the curve, and dynamic blood oxygen level-dependent (BOLD) imaging in calf muscle to measure maximal relative T2* changes and time-to-peak. Data were analyzed by 2 independent MRI readers. Interscan and inter-reader reproducibility were determined as outcome measures and expressed as the coefficient of variation (CV).

RESULTS

Quantification of the number of arteries, artery diameter, and blood flow proved highly reproducible in patients (CV = 2.6%, 4.5%, and 15.8% at interscan level and 9.0%, 8.2%, and 7.0% at interreader level, respectively). Reproducibility of DCE and BOLD MRI was poor in patients with a CV up to 50.9%.

CONCLUSIONS

Quantification of the morphologic vascular status by contrast-enhanced MR angiography, as well as phase contrast angiography MRI to assess macrovascular blood flow proved highly reproducible in both PAD patients and healthy volunteers and might therefore be helpful in studying the development of collateral arteries in PAD patients and in unraveling the mechanisms underlying this process. Functional assessment of the microvascular status using DCE and BOLD, MRI did not prove reproducible at 1.5 T and is therefore currently not suitable for (clinical) application in PAD.

Awareness of anatomical variations for infrapopliteral intervention

With the tremendous advancement and accumulated expertise of endovascular techniques, infrapopliteal intervention is emerging as an alternative therapeutic option to distal bypass surgery for limb salvage in the setting of critical limb ischemia (CLI). However, though much attention has been given to infrapopliteal intervention, the importance of identifying preprocedural infrapopliteal variants remains underappreciated. Becoming more aware of these anatomical variants will translate to increased clinical effectiveness for the patient with infrapopliteal artery disease. Therefore, this review will highlight the fundamental aspects of infrapopliteal variant anatomy for the catheter-based treatment of CLI patients with symptomatic infrapopliteal artery disease.

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.

Multicenter, double-blind, randomized, intraindividual crossover comparison of gadobenate dimeglumine and gadopentetate dimeglumine for MR angiography of peripheral arteries

PURPOSE

To prospectively compare the image quality and diagnostic performance achieved with doses of gadobenate dimeglumine and gadopentetate dimeglumine of 0.1 mmol per kilogram of body weight in patients undergoing contrast material-enhanced magnetic resonance (MR) angiography of the pelvis, thigh, and lower-leg (excluding foot) for suspected or known peripheral arterial occlusive disease.

MATERIALS AND METHODS

Institutional review board approval was granted from each center and informed written consent was obtained from all patients. Between November 2006 and January 2008, 96 patients (62 men, 34 women; mean age, 63.7 years +/- 10.4 [standard deviation]; range, 39-86 years) underwent two identical examinations at 1.5 T by using three-dimensional spoiled gradient-echo sequences and randomized 0.1-mmol/kg doses of each agent. Images were evaluated on-site for technical adequacy and quality of vessel visualization and offsite by three independent blinded readers for anatomic delineation and detection/exclusion of pathologic features. Comparative diagnostic performance was determined in 31 patients who underwent digital subtraction angiography. Data were analyzed by using the Wilcoxon signed-rank, McNemar, and Wald tests. Interreader agreement was determined by using generalized kappa statistics. Differences in quantitative contrast enhancement were assessed and a safety evaluation was performed.

RESULTS

Ninety-two patients received both agents. Significantly better performance (P < .0001; all evaluations) with gadobenate dimeglumine was noted on-site for technical adequacy and vessel visualization quality and offsite for anatomic delineation and detection/exclusion of pathologic features. Contrast enhancement (P < or = .0001) and detection of clinically relevant disease (P < or = .0028) were significantly improved with gadobenate dimeglumine. Interreader agreement for stenosis detection and grading was good to excellent (kappa = 0.749 and 0.805, respectively). Mild adverse events were reported for four (six events) and five (eight events) patients after gadobenate dimeglumine and gadopentetate dimeglumine, respectively.

CONCLUSION

Higher-quality vessel visualization, greater contrast enhancement, fewer technical failures, and improved diagnostic performance are obtained with gadobenate dimeglumine, relative to gadopentetate dimeglumine, when compared intraindividually at 0.1-mmol/kg doses in patients undergoing contrast-enhanced MR angiography for suspected peripheral arterial occlusive disease.

Medical and endovascular management of critical limb ischemia

Critical limb ischemia (CLI) is the term used to designate the condition in which peripheral artery disease has resulted in resting leg or foot pain or in a breakdown of the skin of the leg or foot, causing ulcers or tissue loss. If not revascularized, CLI patients are at risk for limb loss and for potentially fatal complications from the progression of gangrene and the development of sepsis. The management of CLI requires a multidisciplinary team of experts in different areas of vascular disease, from atherosclerotic risk factor management to imaging, from intervention to wound care and physical therapy. In the past decade, the most significant change in the treatment of CLI has been the increasing tendency to shift from bypass surgery to less invasive endovascular procedures as first-choice revascularization techniques, with bypass surgery then reserved as backup if appropriate. The goals of intervention for CLI include the restoration of pulsatile, inline flow to the foot to assist wound healing, the relief of rest pain, the avoidance of major amputation, preservation of mobility, and improvement of patient function and quality of life. The evaluating physician should be fully aware of all revascularization options in order to select the most appropriate intervention or combination of interventions, while taking into consideration the goals of therapy, risk-benefit ratios, patient comorbidities, and life expectancy. We discuss the incidence, risk factors, and prognosis of CLI and the clinical presentation, diagnosis, available imaging modalities, and medical management (including pain and ulcer care, pharmaceutical options, and molecular therapies targeting angiogenesis). The endovascular approaches that we review include percutaneous transluminal angioplasty (with or without adjunctive stenting); subintimal angioplasty; primary femoropopliteal and infrapopliteal deployment of bare nitinol, covered, drug-eluting, or bioabsorbable stents; cryoplasty; excimer laser-assisted angioplasty; excisional atherectomy; and cutting balloon angioplasty.