2012 Criteria for Peripheral Vascular Ultrasound Part I
2012 Criteria for Peripheral Vascular Ultrasound Part I
The noninvasive vascular laboratory plays a central role in the evaluation and surveillance of peripheral vascular disorders. The scope of this document includes common clinical indications encountered in patients with suspected or known non-coronary arterial disorders, including atherosclerotic occlusive disease (i.e., carotid artery stenosis, lower and upper extremity peripheral arterial disease, renal and mesenteric artery occlusive disease), abdominal aortic aneurysms, and also less common disorders such as fibromuscular dysplasia, vasospasm, arterial dissection, and arterial trauma. Evaluation of the thoracic aorta is not generally undertaken in the noninvasive vascular laboratory and is beyond the scope of this document. The appropriate use of transthoracic echocardiography for evaluation of aortic disease is addressed in the 2011 Appropriate Use Criteria for Echocardiography.
Due to the diversity of peripheral vascular disorders, it is likely that many potential clinical indications are not included in this document. Rather than an exhaustive compendium of clinical indications, it is intended that this document address the most common and important clinical scenarios encountered in the care patients with peripheral vascular disease. This document includes ratings for both duplex ultrasound examinations and physiological testing studies (when appropriate). This document includes indications related to arterial disorders only; separate appropriateness criteria for venous ultrasound and physiological testing, which will also include indications related to dialysis access, are under development and anticipated in the near future. It is intended that this document will provide guidance for clinicians in maximizing the appropriate use of the noninvasive vascular laboratory for the care of patients with suspected or known peripheral vascular disorders. In addition, it is intended that this document identify critical evidence gaps in the field and serve as a reference for policy makers with regard to noninvasive vascular testing.
Appropriate Use Criteria were developed using medical evidence and supplemented by expert opinion to assess whether the net benefit or risks of a noninvasive, vascular laboratory–based, diagnostic test for arterial disease make it reasonable to perform. The intent of the criteria is to avoid over- or underutilization, thereby promoting optimal healthcare delivery along with justifying healthcare expenditures and promoting the best outcome for patients with minimal risk.
The AUC for vascular laboratory testing were developed as complimentary and are aligned with the ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease and the ASA/ACC/AHA multisocietal Guidelines for the Management of Patients with Extracranial Carotid and Vertebral Artery disease. Specifically, the ACC/AHA PAD and carotid/vertebral guidelines include, for each vascular territory, a section on diagnostic methods. The current AUC document includes some of the diagnostic methods for disease investigation such as ultrasound and physiological testing. Other modalities such as computed tomography and magnetic resonance are not covered in the current AUC document.
It should be noted that the optimal clinical management of many common peripheral vascular disorders requires periodic imaging surveillance, both to follow for disease progression and to determine the time at which a threshold for intervention has been reached. In contrast to many cardiac conditions, peripheral arterial interventions are often indicated to prevent untoward vascular events in the patient with severe but asymptomatic vascular disease. Examples of such indications include repair of a large but asymptomatic abdominal aortic aneurysm to prevent fatal rupture or revascularization of severe asymptomatic internal carotid artery stenosis to prevent ipsilateral stroke. As such, there are many more surveillance indications included in the current AUC document than in the AUC for other cardiovascular imaging modalities, such as echocardiography or nuclear imaging. In addition, it must be noted that periodic noninvasive vascular testing is a standard component of care following vascular intervention, such as follow-up of a lower extremity bypass graft or arterial stent for significant stenosis or for assessment after endovascular aortic aneurysm repair to assure aneurysm exclusion and the absence of endoleak. In some clinical settings, repeat intervention may be required based solely upon surveillance ultrasound findings in the absence of worsening clinical symptoms, such as to optimize primary assisted patency of a severely stenotic lower extremity bypass graft.
Summary of Evidence and Call for Additional Research A consensus of "appropriate" was found for most vascular studies where clinical signs and symptoms were the indication for testing and to establish a "baseline" after a revascularization procedure. In general, a follow-up study for a patient with a normal baseline study was deemed inappropriate. For cerebrovascular disease, a duplex ultrasound study was appropriate for hemispheric neurological symptoms such as transient ischemic attack or stroke. There was uncertainty regarding the use of cerebrovascular ultrasound for assessment of asymptomatic patients with risk factors or comorbidities for carotid artery stenosis, but this was deemed appropriate for assessment of occult cerebrovascular disease in patients with established atherosclerotic disease in other vascular territories. Another area considered uncertain for cerebrovascular ultrasound was preoperative assessment prior to cardiac surgery.
For duplex ultrasound to assess for renal artery stenosis, appropriate testing indications were hypertension, increased creatinine, and heart failure and for mesenteric artery stenosis were patients with postprandial pain and weight loss who have previously undergone GI evaluation. The appropriate indications for evaluation of the abdominal aorta and iliac arteries included intermittent claudication, an aneurysmal femoral or popliteal pulse, a pulsatile abdominal mass, a decreased or absent femoral pulse, and an abdominal or femoral bruit, as well as clinical evidence of atheroemboli in the lower extremities, abnormal physiological testing suggestive of aortoiliac occlusive disease, and the presence of a thoracic aortic aneurysm. Erectile dysfunction was considered an uncertain indication of duplex ultrasound of the aorta and iliac arteries. Inappropriate indications for aorta and iliac duplex ultrasound were nonspecific discomfort and swelling in lower extremities, fever of unknown origin, and hypertension. Surveillance of known aortic or iliac aneurysms was appropriate but did depend on size of the vessel and rapidity of enlargement.
Lower or upper extremity physiological testing alone or duplex ultrasound with single-level ABI and PVR was appropriate for signs and symptoms of ischemia. Screening tests for the various vascular territories were appropriate for abdominal aortic aneurysms and the ratings were generally consistent with USPSTF recommendations. The screening of selected populations with the ABI was uncertain and reflects the paucity of data regarding effect on prevention of claudication and limb loss. However, it did not address whether ABI screening would impact the high rate of heart attack and stroke in patients with PAD. With regard to carotid artery ultrasound screening, a low Framingham risk score was an inappropriate indication, whereas an intermediate or high Framingham risk score was an uncertain indication. The uncertain indications noted in all the vascular territories exposes the need for outcome and clinical effectiveness data to allow for appropriateness certainly.
The current evidence base and clinical practice guidelines were used to develop and rate the clinical indications whenever available, although for certain indications, the available scientific literature was limited and clinical expertise played a larger role. The writing panel recognizes a need for more clinical and cost-effectiveness studies focused specifically on noninvasive vascular testing, and the significant number of indications rated by the technical panel as "uncertain" are reflective of these evidence gaps. The writing panel identifies the following areas as among those in greatest need of focused research:
Discussion
The noninvasive vascular laboratory plays a central role in the evaluation and surveillance of peripheral vascular disorders. The scope of this document includes common clinical indications encountered in patients with suspected or known non-coronary arterial disorders, including atherosclerotic occlusive disease (i.e., carotid artery stenosis, lower and upper extremity peripheral arterial disease, renal and mesenteric artery occlusive disease), abdominal aortic aneurysms, and also less common disorders such as fibromuscular dysplasia, vasospasm, arterial dissection, and arterial trauma. Evaluation of the thoracic aorta is not generally undertaken in the noninvasive vascular laboratory and is beyond the scope of this document. The appropriate use of transthoracic echocardiography for evaluation of aortic disease is addressed in the 2011 Appropriate Use Criteria for Echocardiography.
Due to the diversity of peripheral vascular disorders, it is likely that many potential clinical indications are not included in this document. Rather than an exhaustive compendium of clinical indications, it is intended that this document address the most common and important clinical scenarios encountered in the care patients with peripheral vascular disease. This document includes ratings for both duplex ultrasound examinations and physiological testing studies (when appropriate). This document includes indications related to arterial disorders only; separate appropriateness criteria for venous ultrasound and physiological testing, which will also include indications related to dialysis access, are under development and anticipated in the near future. It is intended that this document will provide guidance for clinicians in maximizing the appropriate use of the noninvasive vascular laboratory for the care of patients with suspected or known peripheral vascular disorders. In addition, it is intended that this document identify critical evidence gaps in the field and serve as a reference for policy makers with regard to noninvasive vascular testing.
Appropriate Use Criteria were developed using medical evidence and supplemented by expert opinion to assess whether the net benefit or risks of a noninvasive, vascular laboratory–based, diagnostic test for arterial disease make it reasonable to perform. The intent of the criteria is to avoid over- or underutilization, thereby promoting optimal healthcare delivery along with justifying healthcare expenditures and promoting the best outcome for patients with minimal risk.
The AUC for vascular laboratory testing were developed as complimentary and are aligned with the ACC/AHA Guidelines for the Management of Patients with Peripheral Arterial Disease and the ASA/ACC/AHA multisocietal Guidelines for the Management of Patients with Extracranial Carotid and Vertebral Artery disease. Specifically, the ACC/AHA PAD and carotid/vertebral guidelines include, for each vascular territory, a section on diagnostic methods. The current AUC document includes some of the diagnostic methods for disease investigation such as ultrasound and physiological testing. Other modalities such as computed tomography and magnetic resonance are not covered in the current AUC document.
It should be noted that the optimal clinical management of many common peripheral vascular disorders requires periodic imaging surveillance, both to follow for disease progression and to determine the time at which a threshold for intervention has been reached. In contrast to many cardiac conditions, peripheral arterial interventions are often indicated to prevent untoward vascular events in the patient with severe but asymptomatic vascular disease. Examples of such indications include repair of a large but asymptomatic abdominal aortic aneurysm to prevent fatal rupture or revascularization of severe asymptomatic internal carotid artery stenosis to prevent ipsilateral stroke. As such, there are many more surveillance indications included in the current AUC document than in the AUC for other cardiovascular imaging modalities, such as echocardiography or nuclear imaging. In addition, it must be noted that periodic noninvasive vascular testing is a standard component of care following vascular intervention, such as follow-up of a lower extremity bypass graft or arterial stent for significant stenosis or for assessment after endovascular aortic aneurysm repair to assure aneurysm exclusion and the absence of endoleak. In some clinical settings, repeat intervention may be required based solely upon surveillance ultrasound findings in the absence of worsening clinical symptoms, such as to optimize primary assisted patency of a severely stenotic lower extremity bypass graft.
Summary of Evidence and Call for Additional Research A consensus of "appropriate" was found for most vascular studies where clinical signs and symptoms were the indication for testing and to establish a "baseline" after a revascularization procedure. In general, a follow-up study for a patient with a normal baseline study was deemed inappropriate. For cerebrovascular disease, a duplex ultrasound study was appropriate for hemispheric neurological symptoms such as transient ischemic attack or stroke. There was uncertainty regarding the use of cerebrovascular ultrasound for assessment of asymptomatic patients with risk factors or comorbidities for carotid artery stenosis, but this was deemed appropriate for assessment of occult cerebrovascular disease in patients with established atherosclerotic disease in other vascular territories. Another area considered uncertain for cerebrovascular ultrasound was preoperative assessment prior to cardiac surgery.
For duplex ultrasound to assess for renal artery stenosis, appropriate testing indications were hypertension, increased creatinine, and heart failure and for mesenteric artery stenosis were patients with postprandial pain and weight loss who have previously undergone GI evaluation. The appropriate indications for evaluation of the abdominal aorta and iliac arteries included intermittent claudication, an aneurysmal femoral or popliteal pulse, a pulsatile abdominal mass, a decreased or absent femoral pulse, and an abdominal or femoral bruit, as well as clinical evidence of atheroemboli in the lower extremities, abnormal physiological testing suggestive of aortoiliac occlusive disease, and the presence of a thoracic aortic aneurysm. Erectile dysfunction was considered an uncertain indication of duplex ultrasound of the aorta and iliac arteries. Inappropriate indications for aorta and iliac duplex ultrasound were nonspecific discomfort and swelling in lower extremities, fever of unknown origin, and hypertension. Surveillance of known aortic or iliac aneurysms was appropriate but did depend on size of the vessel and rapidity of enlargement.
Lower or upper extremity physiological testing alone or duplex ultrasound with single-level ABI and PVR was appropriate for signs and symptoms of ischemia. Screening tests for the various vascular territories were appropriate for abdominal aortic aneurysms and the ratings were generally consistent with USPSTF recommendations. The screening of selected populations with the ABI was uncertain and reflects the paucity of data regarding effect on prevention of claudication and limb loss. However, it did not address whether ABI screening would impact the high rate of heart attack and stroke in patients with PAD. With regard to carotid artery ultrasound screening, a low Framingham risk score was an inappropriate indication, whereas an intermediate or high Framingham risk score was an uncertain indication. The uncertain indications noted in all the vascular territories exposes the need for outcome and clinical effectiveness data to allow for appropriateness certainly.
The current evidence base and clinical practice guidelines were used to develop and rate the clinical indications whenever available, although for certain indications, the available scientific literature was limited and clinical expertise played a larger role. The writing panel recognizes a need for more clinical and cost-effectiveness studies focused specifically on noninvasive vascular testing, and the significant number of indications rated by the technical panel as "uncertain" are reflective of these evidence gaps. The writing panel identifies the following areas as among those in greatest need of focused research:
Clinical and cost effectiveness of carotid artery duplex examinations prior to open heart surgery.
Cost–benefit analysis and utility of carotid duplex ultrasound examination for asymptomatic patients with atherosclerotic vascular disease in other vascular beds (e.g., coronary or peripheral artery disease) and for patients with multiple atherosclerotic risk factors.
Optimal frequency of ultrasound examinations for surveillance of untreated internal carotid artery stenosis, accounting for severity of disease on the baseline examination.
Optimal frequency of ultrasound examinations for surveillance of abdominal aortic aneurysms, accounting for size of the aneurysm on the baseline examination and select patient characteristics (e.g., gender).
Optimal frequency of ultrasound and physiological testing for surveillance following lower extremity arterial bypass grafts and endovascular revascularization procedures, accounting for type of procedure (stenting or bypass), nature of conduit (for bypass grafting), and anatomic location of the procedure.
Comparative effectiveness of duplex ultrasound versus other imaging modalities for surveillance after aortic endografting.
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