Key messages
Due to the lack of strong evidence, the benefits of intensive surveillance with duplex ultrasound (DUS) after lower limb revascularisation are unclear. No study reported on adverse events relating to DUS surveillance.
What are the benefits of DUS surveillance?
The obstruction or narrowing of the large arteries of the lower limbs, known as lower extremity atherosclerotic disease or peripheral arterial disease, may require revascularisation procedures (surgery to restore blood flow to blocked arteries or veins), especially when the disease is severe or does not improve with non-surgical interventions. DUS scanning is often performed as part of postoperative care after these procedures to identify any flow abnormality that could compromise flow through the graft (graft patency).
What did we want to find out?
We wanted to find out:
- whether close observation (intensive surveillance programmes) with DUS scanning can help avoid minor and major amputations;
- whether intensive surveillance programmes with DUS scanning increase re-intervention rates (procedures performed to maintain graft patency after revascularisation) and death, especially in asymptomatic patients, that is those who do not have pain, intermittent claudication (muscle pain that occurs with exercise and is relieved by rest), or other symptoms.
What did we do?
We searched for studies that compared surveillance programmes with DUS scanning after lower limb revascularisation versus surveillance with medical examination and pulse palpation, with or without any other objective test, such as arterial pressure index.
We compared and summarised the results of the studies and rated our confidence in the evidence based on factors such as study methods and sizes.
What did we find?
We found three studies involving 1092 people with lower extremity atherosclerotic disease (build up of fats, cholesterol, and other substances inside the arteries) who underwent revascularisation procedures. The studies ranged in size from 156 to 594 participants. All of the included studies were conducted in Europe. Two studies lasted less than 24 months, with only one study lasting more than 24 months. The included studies compared DUS plus pulse palpation and arterial pressure index versus pulse palpation and arterial pressure index in people undergoing revascularisation procedures performed in arteries below the inguinal region (groin).
Main results
Intensive surveillance programmes with DUS may lead to little or no difference in limb salvage rate, patency after an intervention performed to treat a graft or vessel after its thrombosis (formation of a blood clot) or stenosis (narrowing), death from all causes, and quality of life.
Intensive surveillance programmes with DUS scanning may increase re-intervention rates.
There were no available data on the effect of surveillance programmes with DUS on adverse events resulting from DUS surveillance.
What are the limitations of the evidence?
Our confidence in the evidence is low. Three main factors reduced our confidence in the evidence:
- not every study provided data on our outcomes of interest;
- in one study, assignment of participants to different groups was not truly random;
- there were only a few studies, and some studies were very small.
How up-to-date is this evidence?
The evidence is current to February 2022.
Based on low certainty evidence, we found no clear difference between DUS and standard surveillance in preventing limb amputation, morbidity, and mortality after lower limb revascularisation. We found no studies on DUS surveillance after angioplasty or stenting (or both), only studies on bypass grafting. High-quality RCTs should be performed to better inform the best medical surveillance of lower limb revascularisation that may reduce the burden of peripheral arterial disease.
Lower extremity atherosclerotic disease (LEAD) – also known as peripheral arterial disease – refers to the obstruction or narrowing of the large arteries of the lower limbs, most commonly caused by atheromatous plaque.
Although in many cases of less severe disease patients can be asymptomatic, the major clinical manifestations of LEAD are intermittent claudication (IC) and critical limb ischaemia, also known as chronic limb-threatening ischaemia (CLTI). Revascularisation procedures including angioplasty, stenting, and bypass grafting may be required for those in whom the disease is severe or does not improve with non-surgical interventions.
Maintaining vessel patency after revascularisation remains a challenge for vascular surgeons, since approximately 30% of vein grafts may present with restenosis in the first year due to myointimal hyperplasia. Restenosis can also occur after angioplasty and stenting. Restenosis and occlusions that occur more than two years after the procedure are generally related to progression of the atherosclerosis. Surveillance programmes with duplex ultrasound (DUS) scanning as part of postoperative care may facilitate early diagnosis of restenosis and help avoid amputation in people who have undergone revascularisation.
To assess the effects of DUS versus pulse palpation, arterial pressure index, angiography, or any combination of these, for surveillance of lower limb revascularisation in people with LEAD.
The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, CINAHL, and LILACS databases and World Health Organization International Clinical Trials Registry Platform and ClinicalTrials.gov trials registers to 1 February 2022.
We included randomised controlled trials (RCTs) and quasi-RCTs that compared DUS surveillance after lower limb revascularisation versus clinical surveillance characterised by medical examination with pulse palpation, with or without any other objective test, such as arterial pressure index measures (e.g. ankle-brachial index (ABI) or toe brachial index (TBI)).
Our primary outcomes were limb salvage rate, vessel or graft secondary patency, and adverse events resulting from DUS surveillance. Secondary outcomes were all-cause mortality, functional walking ability assessed by walking distance, clinical severity scales, quality of life (QoL), re-intervention rates, and functional walking ability assessed by any validated walking impairment questionnaire. We presented the outcomes at two time points: two years or less after the original revascularisation (short term) and more than two years after the original revascularisation (long term).
We used standard Cochrane methodological procedures. We used the Cochrane RoB 1 tool to assess the risk of bias for RCTs and GRADE to assess the certainty of evidence. We performed meta-analysis when appropriate.
We included three studies (1092 participants) that compared DUS plus pulse palpation and arterial pressure index (ABI or TBI) versus pulse palpation and arterial pressure index (ABI or TBI) for surveillance of lower limb revascularisation with bypass. One study each was conducted in Sweden and Finland, and the third study was conducted in the UK and Europe. The studies did not report adverse events resulting from DUS surveillance, functional walking ability, or clinical severity scales.
No study assessed surveillance with DUS scanning after angioplasty or stenting, or both. We downgraded the certainty of evidence for risk of bias and imprecision.
Duplex ultrasound plus pulse palpation and arterial pressure index (ABI or TBI) versus pulse palpation plus arterial pressure index (ABI or TBI) (short-term time point)
In the short term, DUS surveillance may lead to little or no difference in limb salvage rate (risk ratio (RR) 0.84, 95% confidence interval (CI) 0.49 to 1.45; I² = 93%; 2 studies, 936 participants; low-certainty evidence) and vein graft secondary patency (RR 0.92, 95% CI 0.67 to 1.26; I² = 57%; 3 studies, 1092 participants; low-certainty evidence).
DUS may lead to little or no difference in all-cause mortality (RR 1.11, 95% CI 0.70 to 1.74; 1 study, 594 participants; low-certainty evidence).
There was no clear difference in QoL as assessed by the 36-item Short Form Health Survey (SF-36) physical score (mean difference (MD) 2 higher, 95% CI 2.59 lower to 6.59 higher; 1 study, 594 participants; low-certainty evidence); the SF-36 mental score (MD 3 higher, 95% CI 0.38 lower to 6.38 higher; 1 study, 594 participants; low-certainty evidence); or the EQ-5D utility score (MD 0.02 higher, 95% CI 0.03 lower to 0.07 higher; 1 study, 594 participants; low-certainty evidence).
DUS may increase re-intervention rates when considered any therapeutic intervention (RR 1.38, 95% CI 1.05 to 1.81; 3 studies, 1092 participants; low-certainty evidence) or angiogram procedures (RR 1.53, 95% CI 1.12 to 2.08; 3 studies, 1092 participants; low-certainty evidence).
Duplex ultrasound plus pulse palpation and arterial pressure index (ABI or TBI) versus pulse palpation plus arterial pressure index (ABI or TBI) (long-term time point)
One study reported data after two years, but provided only vessel or graft secondary patency data. DUS may lead to little or no difference in vessel or graft secondary patency (RR 0.83, 95% CI 0.19 to 3.51; 1 study, 156 participants; low-certainty evidence). Other outcomes of interest were not reported at the long-term time point.