Note: This guideline has been updated. The National Guideline Clearinghouse (NGC) is working to update this summary.

Recurrent symptoms following lower extremity angioplasty for arterial obstructive disease:

• Claudication
• Threatened limb

To evaluate the appropriateness of initial radiologic examinations for recurrent symptoms following lower extremity angioplasty

Patients with recurrent symptoms following lower extremity angioplasty for arterial obstructive disease

Utility of radiologic examinations in evaluation of lower extremity arterial obstructive disease

Literature Search Procedure

The Medline literature search is based on keywords provided by the topic author. The two general classes of keywords are those related to the condition (e.g., ankle pain, fever) and those that describe the diagnostic or therapeutic intervention of interest (e.g., mammography, MRI).

The search terms and parameters are manipulated to produce the most relevant, current evidence to address the American College of Radiology Appropriateness Criteria (ACR AC) topic being reviewed or developed. Combining the clinical conditions and diagnostic modalities or therapeutic procedures narrows the search to be relevant to the topic. Exploding the term "diagnostic imaging" captures relevant results for diagnostic topics.

The following criteria/limits are used in the searches.

1. Articles that have abstracts available and are concerned with humans.
2. Restrict the search to the year prior to the last topic update or in some cases the author of the topic may specify which year range to use in the search. For new topics, the year range is restricted to the last 5 years unless the topic author provides other instructions.
3. May restrict the search to Adults only or Pediatrics only.
4. Articles consisting of only summaries or case reports are often excluded from final results.

The search strategy may be revised to improve the output as needed.

The total number of source documents identified as the result of the literature search is not known.

Strength of Evidence Key

Category 1 - The conclusions of the study are valid and strongly supported by study design, analysis and results.

Category 2 - The conclusions of the study are likely valid, but study design does not permit certainty.

Category 3 - The conclusions of the study may be valid but the evidence supporting the conclusions is inconclusive or equivocal.

Category 4 - The conclusions of the study may not be valid because the evidence may not be reliable given the study design or analysis.

The topic author drafts or revises the narrative text summarizing the evidence found in the literature. American College of Radiology (ACR) staff draft an evidence table based on the analysis of the selected literature. These tables rate the strength of the evidence for all articles included in the narrative text.

The expert panel reviews the narrative text, evidence table, and the supporting literature for each of the topic-variant combinations and assigns an appropriateness rating for each procedure listed in the table. Each individual panel member forms his/her own opinion based on his/her interpretation of the available evidence.

More information about the evidence table development process can be found in the ACR Appropriateness Criteria® Evidence Table Development document (see "Availability of Companion Documents" field).

Modified Delphi Technique

The appropriateness ratings for each of the procedures included in the Appropriateness Criteria topics are determined using a modified Delphi methodology. A series of surveys are conducted to elicit each panelist's expert interpretation of the evidence, based on the available data, regarding the appropriateness of an imaging or therapeutic procedure for a specific clinical scenario. American College of Radiology (ACR) staff distributes surveys to the panelists along with the evidence table and narrative. Each panelist interprets the available evidence and rates each procedure. The surveys are completed by panelists without consulting other panelists. The ratings are a scale between 1 and 9, which is further divided into three categories: 1, 2, or 3 is defined as "usually not appropriate"; 4, 5, or 6 is defined as "may be appropriate"; and 7, 8, or 9 is defined as "usually appropriate." Each panel member assigns one rating for each procedure per survey round. The surveys are collected and the results are tabulated, de-identified and redistributed after each round. A maximum of three rounds are conducted. The modified Delphi technique enables each panelist to express individual interpretations of the evidence and his or her expert opinion without excessive bias from fellow panelists in a simple, standardized and economical process.

Consensus among the panel members must be achieved to determine the final rating for each procedure. Consensus is defined as eighty percent (80%) agreement within a rating category. The final rating is determined by the median of all the ratings once consensus has been reached. Up to three rating rounds are conducted to achieve consensus.

If consensus is not reached, the panel is convened by conference call. The strengths and weaknesses of each imaging procedure that has not reached consensus are discussed and a final rating is proposed. If the panelists on the call agree, the rating is accepted as the panel's consensus. The document is circulated to all the panelists to make the final determination. If consensus cannot be reached on the call or when the document is circulated, "No consensus" appears in the rating column and the reasons for this decision are added to the comment sections.

Not applicable

A formal cost analysis was not performed and published cost analyses were not reviewed.

Criteria developed by the Expert Panels are reviewed by the American College of Radiology (ACR) Committee on Appropriateness Criteria.

Note: This guideline has been updated. The National Guideline Clearinghouse (NGC) is working to update this summary. The recommendations that follow are based on the previous version of the guideline.

ACR Appropriateness Criteria®

Clinical Condition: Recurrent Symptoms Following Lower Extremity Angioplasty

Variant 1: Claudication.

Radiologic Procedure	Rating	Comments	RRL*
US segmental Doppler pressures and pulse volume recordings	9	Usual first tests.	O
MRA lower extremity with contrast	8	Able to triage between catheter and surgical management and thus may substitute for other noninvasive studies. See statement regarding contrast in text under "Anticipated Exceptions."	O
US lower extremity with Doppler	8	May be useful to identify focal lesions amenable to percutaneous intervention.	O
Arteriography lower extremity	7	Used for a lesion amenable to percutaneous intervention (e.g., restenosis).
CTA lower extremity	7	Can be an alternative to MRA. Heavy calcification, especially in calf arteries, can limit evaluation of outflow disease.
US lower extremity intravascular	1	May be indicated as part of an interventional procedure but not for diagnostic use.	O
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Variant 2: Threatened limb.

Radiologic Procedure	Rating	Comments	RRL*
Arteriography lower extremity	9	Allows most timely diagnosis and treatment.
US segmental Doppler pressures and pulse volume recordings	8		O
MRA lower extremity with contrast	5	Useful if angiography is not performed (i.e., surgical treatment is necessary). See statement regarding contrast in text under "Anticipated Exceptions."	O
CTA lower extremity	5	Useful if angiography is not performed with limitations as described above.
US lower extremity with Doppler	4	May be useful to identify focal lesions amenable to percutaneous intervention.	O
Rating Scale: 1,2,3 Usually not appropriate; 4,5,6 May be appropriate; 7,8,9 Usually appropriate			*Relative Radiation Level

Note: Abbreviations used in the tables are listed at the end of the "Major Recommendations" field.

Summary of Literature Review

Endovascular interventions for lower extremity arterial obstructive disease, both for lifestyle-limiting claudication and for critical ischemia with threatened limb, have become accepted treatment modalities. With its increased availability in the United States, endovascular intervention is now more common than bypass surgery and has reduced the number of surgical reconstructive procedures. In spite of very high initial technical success rates, restenosis after angioplasty with recurrent symptoms is frequent, especially with infrainguinal lesions.

The use of nitinol stents appears to decrease restenosis in the peripheral arteries. Several investigators have used drug-eluting stents in infrapopliteal arteries and showed promising results. However, data from long-term studies are still being obtained.

There are few studies focused on the importance of patient follow-up after lower-extremity intervention. Recurrent symptoms usually precede the onset of limb- or life-threatening events, in contrast to coronary artery disease. Thus, patient evaluation has often been driven by recurrence of symptoms.

Clinical examination with evaluation of the peripheral pulses and determination of the ankle-brachial indices (ABIs) is a low-cost and well-accepted first step in evaluation. A recommended strategy is a baseline post-treatment ABI followed with repeat study after 3 to 6 months to assess continued patency.

Restenosis is often undetected clinically, since the natural progression of the patient's disease process is often characterized by new lesions at different sites. Thus definitive diagnosis is important for therapeutic planning, whether for repeat endovascular intervention, for reconstructive vascular surgery, or for medical management.

Noninvasive Hemodynamic Studies

Segmental Doppler pressures (SDP) measurements and pulse volume recordings (PVR) (commonly referred to as lower extremity noninvasives [LENIs]) are the most commonly performed noninvasive techniques for evaluating peripheral vascular disease. Deterioration of SDP from previous levels by 15% or more has been accepted as indicative of restenosis. However, this measurement does not clearly specify the site or length of the lesion beyond general terms, such as "femoropopliteal" or "inflow" disease, and it is of little value in patients with noncompressible arteries, as often occurs in diabetics and patients with renal insufficiency. Similarly, segmental PVR, a useful adjunct in calcified arteries, is not accurate with regard to location or length of lesions nor does it provide specific enough information for treatment decision-making in patients with symptomatic recurrent peripheral vascular disease. In conjunction with ABIs, however, it does provide a useful guide to the overall clinical severity of the obstructive disease.

Ultrasound Imaging

Duplex color Doppler ultrasound (US) imaging is the lowest-cost cross-sectional imaging modality and has widespread usage and acceptance in this patient population. US is recommended for routine surveillance and in the setting of recurrent symptoms following surgical or percutaneous intervention. It has the ability to localize lesion sites and assess their hemodynamic significance.

One limitation of US is its operator dependence. With meticulous technique (by either a technologist or a physician), there is a high, although not perfect, correlation with catheter angiography, especially for infrainguinal disease. A second limitation is that US alone is unable to triage patients between catheter and surgical management. The DIPAD study showed that duplex ultrasonography was less clinically useful than magnetic resonance angiography (MRA) or computed tomography angiography (CTA), with also being less expensive. As discussed below, contrast-enhanced magnetic resonance angiography (CE-MRA) is more sensitive and specific for peripheral arterial disease.

Catheter Angiography

Although the acceptance of MRA, CTA, and US has decreased the role of catheter angiography with digital subtraction, it is still considered the gold standard for peripheral arterial imaging. It allows for intervention at the time of diagnosis, which can prove invaluable in patients with a threatened limb. Contrast-based catheter angiography can localize and quantify obstructive lesions with an accuracy exceeded only by intravascular US. Moreover, it allows physiological evaluation by determining pressure gradients. In addition to its diagnostic capabilities, it permits immediate intervention in many circumstances. In high-acuity settings, such as a thrombosed bypass graft, where immediate catheter-based intervention is likely to be indicated, direct referral to catheter angiography is the preferred option. However, catheter angiography is an invasive technique with a small but definite risk in every patient and a variable higher risk in patients with severe widespread vascular disease, diabetes, renal insufficiency, or other contraindications to the use of iodinated contrast media. CO₂-negative contrast angiography may be of value in these patients. In light of the risk of nephrogenic systemic fibrosis (NSF) in patients with severe renal disease, there is no role for gadolinium chelates as x-ray contrast agents.

Computed Tomography Angiography

Early multidetector CT (MDCT) had insufficient spatial resolution, temporal resolution, and volume coverage per gantry rotation to adequately evaluate the lower extremity arterial system. With improvements in technology, CTA is rapidly evolving in the imaging of peripheral vascular obstructive disease. It now has the advantage of allowing very rapid, noninvasive evaluation of a large portion of the arterial tree (for example, from the level of the renal arteries to the foot vessels).

CTA can be used to study segmented arterial components and is particularly good for evaluating aortoiliac disease, especially with its ability to view the image in coronal, sagittal, and additional views. Because of this volumetric assessment, CTA can detect some vascular segments that would be unrecognized by catheter angiography. CTA findings can influence correct treatment recommendations. Although particularly useful for evaluating a defined vascular segment, CTA is still somewhat limited in the ability to grade the severity of stenotic lesions accurately when the presence of calcium plaques is significant with respect to the vessel diameter, and thus CTA can be limited in surgical planning to treat touch-down in the calf. Another drawback of CTA is artifact from stents. Finally, although relatively noninvasive when compared with catheter angiography, CTA has similar relative limitations related to iodinated contrast medium.

Magnetic Resonance Angiography

Gadolinium-enhanced MRA is a widely used modality for imaging arterial obstructive disease. MR is a noninvasive, low-risk modality to image the entire vascular system, including difficult-to-visualize tibial and pedal arteries. Recent work at 3 Tesla with parallel imaging and multichannel coils has shown nearly isotropic submillimeter voxels throughout the entire peripheral arterial tree. Time-resolved MRA may correlate more accurately with catheter angiography, especially in the calf vessels where minimizing venous contamination is essential. Moreover, in a patient with total occlusion, MRA more reliably defines the reconstituted vessels. Metallic stents, especially stainless steel, cause signal intensity dropout, which can be indistinguishable from an occlusion. This is less of a problem with nitinol stents. MRA is now widely available, and its use, especially in conjunction with duplex vascular US, allows reliable determination of appropriate intervention when symptoms occur after angioplasty. It takes longer to acquire images with MRA when compared to CTA. However, there is no ionizing radiation, and the nephrotoxicity of gadolinium-based contrast is generally considered less than that from iodinated contrast agents. The identification of NSF in patients with chronic renal insufficiency has likely reduced MRA utilization in this patient population (see "Anticipated Exceptions" section). In patients at high risk, noncontrast MRA may prove useful to direct patient management. Recent noncontrast MRA studies show shorter acquisitions than time-of-flight or phase-contrast techniques. Further improvements, in particular for the depiction of pedal circulation, will be required.

Summary

A complete vascular physical examination, including measurement of the ABIs, is always the first step in assessing a patient with recurrent symptoms after an initially successful endovascular intervention. With this knowledge the clinician/angiographer can decide on appropriate imaging studies. If it is clear that reintervention is necessary, as is often the case with a threatened limb, proceeding directly to catheter angiography is timely and appropriate. Preliminary US imaging in less urgent cases may be helpful to define the problem by confirming a recurrence at the previously treated site or suggesting progression elsewhere.

Both MRA and CTA continue to develop and thus are likely to assume a greater role in patient evaluation. Some of the development is evolutionary, such as the use of time-resolved sequences in CE-MRA or the techniques of noncontrast MRA. Additional early work includes imaging the graft vessel wall in addition to the lumen to give further information towards understanding the biology of recurrent disease after intervention in patients with peripheral arterial disease. In parallel with developments in imaging technology, new gadolinium-based MR contrast agents with improved properties for vascular imaging have been developed. The U.S. Food and Drug Administration (FDA) recently approved gadofosveset trisodium, a molecule that binds more strongly to serum albumin than other gadolinium agents, resulting in a better visualization of vascular system. Gadobenate dimeglumine also has advantages in vascular depiction in comparison to other conventional gadolinium-based agents.

Another fundamental development is CTA with two keV settings (dual-energy CT), in theory allowing separation between calcium and iodinated contrast material. However, plaque subtraction is still challenging, particularly for infrapopliteal lesions.

As with the new techniques and contrast agents discussed above, at present there is only anecdotal experience, and thus while extremely promising, use of these advanced strategies must ultimately be supported by scientific evidence. Current MRI and CT protocols are robust, but they are somewhat limited in practice by the meager distribution of high-end MRI and MDCT equipment and the limited number of professionals trained to use them. However, where this equipment and expertise are more available, the improved accuracy, comprehensiveness, and reproducibility of MRI and CT make them appropriate first examinations after clinical examination. The choice of modality is usually related to the expertise of the imager. MRA still has the advantage of more easily visualizing lesions obscured by overlying bone cortex in the calf, in particular the anterior tibial artery. In properly screened patients or in patients who are at risk for significant reactions to iodinated contrast agents, MRA is the procedure of choice.

• The ankle-brachial index is the routine first step in assessing patients with recurrent symptoms.
• Catheter-based angiography is the gold standard in patients with a threatened limb, allowing for intervention at the time of diagnosis.
• Both MRI and CT can be used to triage between catheter and surgical management.

Anticipated Exceptions

Patients presenting with critical recurrent ischemia with motor and sensory deficit occurring shortly after a percutaneous intervention (<7-10 days), and in whom the anatomy is well understood, should proceed directly to surgical revascularization by bypass or mechanical thrombectomy.

Nephrogenic systemic fibrosis (NSF) is a disorder with a scleroderma-like presentation and a spectrum of manifestations that can range from limited clinical sequelae to fatality. It appears to be related to both underlying severe renal dysfunction and the administration of gadolinium-based contrast agents. It has occurred primarily in patients on dialysis, rarely in patients with very limited glomerular filtration rate (GFR) (i.e., <30 mL/min/1.73m²), and almost never in other patients. There is growing literature regarding NSF. Although some controversy and lack of clarity remain, there is a consensus that it is advisable to avoid all gadolinium-based contrast agents in dialysis-dependent patients unless the possible benefits clearly outweigh the risk, and to limit the type and amount in patients with estimated GFR rates <30 mL/min/1.73m². For more information, please see the American College of Radiology (ACR) Manual on Contrast Media (see the "Availability of Companion Documents" field).

Abbreviations

• CTA, computed tomography angiography
• MRA, magnetic resonance angiography
• US, ultrasound

Relative Radiation Level Designations

Relative Radiation Level*	Adult Effective Dose Estimate Range	Pediatric Effective Dose Estimate Range
O	0 mSv	0 mSv
	<0.1 mSv	<0.03 mSv
	0.1-1 mSv	0.03-0.3 mSv
	1-10 mSv	0.3-3 mSv
	10-30 mSv	3-10 mSv
	30-100 mSv	10-30 mSv
*RRL assignments for some of the examinations cannot be made, because the actual patient doses in these procedures vary as a function of a number of factors (e.g., region of the body exposed to ionizing radiation, the imaging guidance that is used). The RRLs for these examinations are designated as NS (not specified).

Algorithms were not developed from criteria guidelines.

The recommendations are based on analysis of the current literature and expert panel consensus.

Selection of appropriate radiologic imaging procedures for evaluation of patients with recurrent symptoms following lower extremity angioplasty

Catheter angiography has a variable higher risk in patients with severe widespread vascular disease, diabetes, renal insufficiency, and other contraindications to the use of iodinated contrast media.

The American College of Radiology (ACR) Committee on Appropriateness Criteria and its expert panels have developed criteria for determining appropriate imaging examinations for diagnosis and treatment of specified medical condition(s). These criteria are intended to guide radiologists, radiation oncologists, and referring physicians in making decisions regarding radiologic imaging and treatment. Generally, the complexity and severity of a patient's clinical condition should dictate the selection of appropriate imaging procedures or treatments. Only those examinations generally used for evaluation of the patient's condition are ranked. Other imaging studies necessary to evaluate other co-existent diseases or other medical consequences of this condition are not considered in this document. The availability of equipment or personnel may influence the selection of appropriate imaging procedures or treatments. Imaging techniques classified as investigational by the U.S. Food and Drug Administration (FDA) have not been considered in developing these criteria; however, study of new equipment and applications should be encouraged. The ultimate decision regarding the appropriateness of any specific radiologic examination or treatment must be made by the referring physician and radiologist in light of all the circumstances presented in an individual examination.

An implementation strategy was not provided.

Not applicable: The guideline was not adapted from another source.

The American College of Radiology (ACR) provided the funding and the resources for these ACR Appropriateness Criteria®.

Committee on Appropriateness Criteria, Expert Panel on Vascular Imaging

Panel Members: Frank J. Rybicki, MD, PhD (Principal Author and Panel Vice-Chair); Kanako K. Kumamaru, MD (Research Author); E. Kent Yucel, MD (Panel Chair); Richard A. Baum, MD; Benoit Desjardins, MD, PhD; Scott D. Flamm, MD; W. Dennis Foley, MD; Michael R. Jaff, DO; Scott A. Koss, MD; Leena Mammen, MD; M. Ashraf Mansour, MD; Emile R. Mohler III, MD; Vamsidhar R. Narra, MD; Matthew P. Schenker, MD

Not stated

Note: This guideline has been updated. The National Guideline Clearinghouse (NGC) is working to update this summary.

Electronic copies of the updated guideline: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.

Print copies: Available from the American College of Radiology, 1891 Preston White Drive, Reston, VA 20191. Telephone: (703) 648-8900.

The following are available:

• ACR Appropriateness Criteria®. Overview. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the American College of Radiology (ACR) Web site.
• ACR Appropriateness Criteria®. Literature search process. Reston (VA): American College of Radiology; 1 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Evidence table development. Reston (VA): American College of Radiology; 4 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria®. Radiation dose assessment introduction. Reston (VA): American College of Radiology; 2 p. Electronic copies: Available in Portable Document Format (PDF) from the ACR Web site.
• ACR Appropriateness Criteria® Manual on contrast media. Reston (VA): American College of Radiology; 90 p. Electronic copies: Available in PDF from the ACR Web site.

None available

This summary was completed by ECRI on February 20, 2001. The information was verified by the guideline developer on March 14, 2001. This summary was updated by ECRI on March 31, 2003. The updated information was verified by the guideline developer on April 21, 2003. This summary was updated by ECRI on March 20, 2006. This summary was updated by ECRI Institute on May 17, 2007 following the U.S. Food and Drug Administration (FDA) advisory on Gadolinium-based contrast agents. This summary was updated by ECRI Institute on June 20, 2007 following the U.S. Food and Drug Administration (FDA) advisory on gadolinium-based contrast agents. This summary was updated by ECRI Institute on August 4, 2009. This NGC summary was updated by ECRI Institute on February 23, 2011.

Instructions for downloading, use, and reproduction of the American College of Radiology (ACR) Appropriateness Criteria® may be found on the ACR Web site .