Key Points
- All vascular procedures have modes of failure that must be identified and managed appropriately to provide the best possible long-term results.
- It is generally accepted that achieving optimal outcomes from open surgical and endovascular procedures depends on periodic follow-up and appropriate reintervention.
- The options for follow-up range from a simple vascular history and physical examination (often including ankle-brachial index [ABI] measurement for procedures involving the lower extremity arteries) to sophisticated imaging methods such as computed tomography (CT) or magnetic resonance (MR) angiography and more invasive catheter angiography.
- Noninvasive vascular laboratory tests, particularly duplex ultrasound (DUS), are ideally suited for this purpose because they are safe and relatively low in cost, and they provide objective anatomic and physiologic information that can be used to assess the durability of a vascular intervention over time.
- The goal of routine surveillance is to identify intervention sites that are at risk for failure, even in the absence of signs or symptoms. However, this approach is justified only if the consequences of failure are severe and early reintervention can improve the outcome.
- Additional requirements are the availability of accurate testing methods with clinically relevant threshold criteria and appropriate follow-up or testing intervals.
Diagnosis
Extracranial Carotid Artery
- After carotid endarterectomy (CEA) or carotid artery stenting (CAS), the Society for Vascular Surgery (SVS) recommends surveillance with DUS at baseline and every 6 months for 2 years and annually thereafter until stable (i.e., until no restenosis or in-stent restenosis [ISR] is observed in two consecutive annual scans). The first or baseline DUS should occur soon after the procedure, preferably within 3 months, with the goal of establishing a post-treatment baseline. Considering the small risk of delayed restenosis or ISR, some interval of regular surveillance (e.g., every 2 years) should be maintained for the life of the patient. (1-B)
- For patients undergoing CAS with diabetes, aggressive patterns of ISR (type IV), prior treatment for ISR, prior cervical radiation or heavy calcification, in addition to the baseline DUS the SVS recommends surveillance with DUS every 6 months until a stable clinical pattern is established and annually thereafter. (1-B)
- The SVS recommends that DUS after CAS include at least the following assessments (1-C):
- Doppler measurement of peak systolic velocity (PSV) and end-diastolic velocity (EDV) in the native common carotid artery (CCA); in the proximal, mid, and distal stent; and in the distal native internal carotid artery (ICA). Modified threshold velocity criteria should be used to interpret the significance of these velocity measurements after CAS.
- B-mode imaging should be used to supplement and to enhance the accuracy of velocity criteria to estimate the severity of luminal narrowing.
Figure 1. Morphologic Patterns of ISR Based on B-mode Imaging
Type I, focal ≤10 mm, end-stent lesions; Type II, focal ≤10 mm, intrastent lesions; Type III, diffuse >10 mm, intrastent lesions; Type IV, diffuse >10 mm, proliferative lesions extending outside the stent; and Type V, total occlusion.
Table 1. Optimal Velocity Threshold Criteria for Varying Severity of ISR After CAS
Thoracic and Abdominal Aorta
- The SVS recommends contrast-enhanced CT scanning at 1 month and 12 months and then annually after thoracic endovascular aortic repair (TEVAR) for thoracic aortic aneurysm. If the 1-month CT scan detects an abnormality, a repeated CT scan at 6 months should be considered. (1-B)
- The SVS recommends contrast-enhanced CT scanning at 1 month, 6 months, and 12 months and then annually after TEVAR for thoracic aortic dissection. (1-B)
- The SVS recommends contrast-enhanced CT scanning at 1 month and 12 months and then annually after TEVAR for blunt thoracic aortic injury. If the 1-month CT scan detects an abnormality, a repeated CT scan at 6 months should be considered. Future studies may provide data to support longer surveillance intervals after TEVAR for traumatic injury once a stable clinical pattern is established. (1-B)
- The SVS recommends CT scanning with or without contrast enhancement at 5-year intervals after open surgical repair for thoracic aortic disease. (1-C)
- The SVS recommends contrast-enhanced CT scanning at 1 month and 12 months after endovascular aneurysm repair (EVAR), with consideration of more frequent imaging if an endoleak or other abnormality of concern is detected at 1 month. (1-B)
- The SVS recommends DUS at 12-month intervals as alternative imaging surveillance after EVAR if no endoleak or sac enlargement was detected during the first year. (1-B)
- The SVS recommends DUS and non-contrast-enhanced CT scanning as alternative imaging surveillance after EVAR in patients with contraindications to iodinated contrast agents. (1-B)
- The SVS recommends total aortic imaging with non-contrast-enhanced CT scanning at 5-year intervals after open surgical repair or EVAR to detect aneurysmal degeneration of other aortic segments. (1-C)
Mesenteric Arteries
- There are no prospective reports documenting the efficacy of a surveillance protocol after mesenteric artery stenting or bypass grafts. However, recurrent mesenteric ischemia is potentially life-threatening. Therefore, after mesenteric artery (celiac, superior mesenteric, and inferior mesenteric) angioplasty with or without stenting or mesenteric artery bypass grafting, the SVS recommends the following (1-C):
- Clinical follow-up and baseline DUS within 1 month of the procedure.
- Clinical follow-up and DUS at 6 months, 12 months, and then annually thereafter.
- The SVS suggests contrast imaging for patients with symptoms of recurrent mesenteric ischemia after mesenteric artery stents or bypass grafts or for the following DUS findings (2-C):
- Celiac axis: PSV >370 cm/s or a substantial increase from the post-treatment baseline PSV.*
- Superior mesenteric artery: PSV >420 cm/s or a substantial increase from the post-treatment baseline PSV.*
- Inferior mesenteric artery: Substantial increase from the post-treatment baseline PSV.*
Renal Arteries
- There are no prospective reports documenting the efficacy of a surveillance protocol after renal artery interventions. After renal artery angioplasty with or without stenting or renal artery bypass or endarterectomy, the SVS suggests the following (2-C):
- Clinical follow-up and baseline DUS within 1 month of the procedure.
- Clinical follow-up and DUS at 6 months and 12 months and then annually thereafter.
- The SVS suggests contrast-enhanced imaging for loss of renal parenchyma (a decrease in kidney length of >1 cm) or for the following DUS findings (2-B):
- Renal artery: PSV ≥280 cm/s or a substantial increase from the post-treatment baseline PSV.*
- Renal to aortic velocity ratio of ≥4.5.
* What constitutes a substantial increase has not been defined.
Open Lower Extremity Arterial Revascularization
- The SVS recommends clinical examination and ABI, with or without the addition of DUS, in the early postoperative period to provide a baseline for further followup after:
- aortobifemoral bypass
- iliofemoral bypass
- femoral-femoral bypass
- axillobifemoral bypass
- Based on the high prevalence of abnormalities detected by DUS as well as the relatively low associated cost and risks, the SVS recommends clinical examination, ABI, and DUS for infrainguinal vein graft surveillance. This should include an early postoperative baseline evaluation and follow-up at 3, 6, and 12 months and at least annually thereafter. (1-B)More frequent surveillance may be considered when uncorrected abnormalities are identified on DUS or when alternative vein conduits (other than great saphenous vein) are used.
- After prosthetic infrainguinal bypass grafts, the SVS recommends clinical examination and ABI, with or without the addition of DUS, in the early postoperative period to provide a baseline for further follow-up. This evaluation should be repeated at 6 and 12 months and then annually as long as there are no new signs or symptoms. (1-B)
Table 2. DUS Velocity and ABI Threshold Criteria for Stratification of Risk for Thrombosis of Infrainguinal Vein Grafts
| Category | High-velocity criteria (PSV) | Velocity ratio (Vr) | Low-velocity criteria (GFV) | Change in ABI |
|---|---|---|---|---|
| Highest risk | >300 cm/s | >3.5 | <45 cm/s | >0.15 |
| High risk | >300 cm/s | >3.5 | >45 cm/s | <0.15 |
| Moderate risk | 180–300 cm/s | >2.0 | >45 cm/s | <0.15 |
| Low risk | <180 cm/s | <2.0 | >45 cm/s | <0.15 |
Adapted from Bandyk DF, Seabrook GR, Moldenhauer P, Lavin J, Edward J, Cato R, et al. Hemodynamics of vein graft stenosis. J Vasc Surg. 1988;8:688-95.
Endovascular Lower Extremity Arterial Revascularization
- The SVS recommends clinical examination, ABI, and DUS within the first month after aortoiliac segment endovascular therapy (EVT) to provide a post-treatment baseline and to evaluate for residual stenosis. Clinical examination and ABI, with or without the addition of DUS, should be performed at 6 and 12 months and then annually as long as there are no new signs or symptoms. (1-C)
- The SVS suggests clinical examination, ABI, and DUS within the first month after femoropopliteal artery EVT to provide a post-treatment baseline and to evaluate for residual stenosis. Continued surveillance at 3 months and then every 6 months is indicated for the following (2-C):
- Patients with interventions using stents because of the potential increased difficulty of treating an occlusive vs. stenotic in-stent lesion.
- Patients undergoing angioplasty or atherectomy for critical limb ischemia because of increased risk of recurrent critical limb ischemia should the intervention fail.
- The SVS suggests clinical examination, ABI, and DUS within the first month after tibial artery EVT to provide a post-treatment baseline and to evaluate for residual stenosis. Continued surveillance at 3 months and then every 6 months should be considered. Those patients with a deteriorating clinical vascular examination, return of rest pain, nonhealing wounds or new tissue loss should undergo repeated DUS. (2-C)
