Historical Background
In recent years there has been a shift in the treatment of aortoiliac occlusive disease (AIOD) from open surgical treatment to endovascular interventions. Endovascular treatment for Trans-Atlantic Inter-Society Consensus (TASC) class A lesions is considered standard. Recommendations are not as clear for more complex disease, including TASC class B and C lesions, but even these are often treated with interventional therapy with excellent results. As catheter-based interventions have advanced, the treatment spectrum has widened to include TASC class D lesions ( Table 31-1 ). Although, a surgical approach continues to be recommended for patients with low operative risk for complex aortic and iliac TASC class D lesions, recent studies have revealed comparable technical success and durability when compared with open reconstruction. A hybrid approach for treating occlusive disease that extends into the femoral arteries has further increased endovascular options for AIOD.
| Study | No. Patients (technical success rate, %) | Follow-up (yr) | Primary Patency (%) | Secondary Patency (%) | Limb Salvage (%) |
|---|---|---|---|---|---|
| Uher et al. | 73 (97) | 3 | 69 | 81 | NR |
| Henry et al. | 105 (88) | 6 | 52 | 66 | NR |
| Leville et al. | 92 (91) | 3 | 76 | 90 | 97 |
| Kashyap et al. | 86 (100) | 3 | 74 | 95 | 98 |
| Rzucidlo et al. | 34 (100) | 1 | 70 | 88 | 100 |
Preoperative Care
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Preoperative physical examination should include a determination of ankle-brachial index; assessment of severity of comorbidities, including renal, cardiac, and functional limitations; and estimated life expectancy. Patients who cannot tolerate general anesthesia and have limited life expectancy, minimal functional performance, or a hostile abdomen may be better served with endovascular treatment.
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Preoperative imaging is performed to determine the extent of aortoiliac disease, with particular attention given to associated common femoral artery or infrainguinal disease. Computed tomography angiography is preferred over conventional angiography and magnetic resonance angiography because of its capacity to assess arterial calcification. In patients with renal insufficiency (estimated glomerular filtration rate of less than 45 mL/min/1.73 m 2 ), hydration is recommended before and after the imaging.
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Optimization of comorbidities should be undertaken as follows:
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Patients with significant renal insufficiency should be admitted before intervention for hydration. Volume loading with sodium bicarbonate and N -acetylcysteine has been shown to reduce risk of renal failure.
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Smoking cessation reduces graft failure, risk of myocardial infarction, and progression of peripheral artery disease.
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Perioperative beta-blockade is recommended for patients with cardiac disease.
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Aspirin is recommended at a daily dosage of 162 to 325 mg, and clopidogrel (75 mg daily) has been found to reduce the risk of ischemic events.
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Most endovascular procedures can be performed under local anesthesia and sedation. However, if a hybrid procedure is planned, regional or general anesthesia is recommended. Cardiac stress testing has been recommended for patients undergoing vascular surgery, but recent evidence suggests a selective approach to testing may be appropriate based on the application of a cardiac risk index.
Pitfalls and Danger Points
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Rupture. Increased risk in small, calcified vessels is often observed in female patients. The external iliac artery is most vulnerable. In high-risk situations an access sheath should be selected at the outset that allows delivery of a covered stent.
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Dissection
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Embolization
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Thrombosis. Activated clotting time (ACT) should be maintained between 250 and 300 seconds during interventions.
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Access site bleeding
Endovascular Strategy
The TASC classification of aortic and iliac artery occlusive disease provides a framework for considering endovascular options and outcomes (see Table 30-1 ). Endovascular treatment is preferred for TASC class A and B lesions. However, surgery should be considered for treatment of TASC class C and D disease in patients at low operative risk, with endovascular approaches reserved for high-risk patients or those with other factors, such as a hostile abdomen, that would complicate surgical repair.
Unfavorable Anatomic Features for Interventions on Common and External Iliac Arteries
Large irregular calcifications, especially close to the aortic or iliac bifurcation, increase concern for vessel rupture during stenting or dilation and may require a covered stent. Extension of disease into the common femoral artery precludes stenting in this region, and a hybrid procedure with femoral endarterectomy should be considered.
Adjunctive Thrombolysis and Percutaneous Mechanical Thrombectomy
Motarjeme and associates found that a short course of thrombolysis may assist in crossing an aortoiliac occlusive lesion. However, most lesions can be crossed without the need for thrombolysis, and its routine use is not necessary. Thrombolysis may reduce the juxtarenal thrombus burden before stent placement as a means to decrease renal emboli. The role of percutaneous mechanical thrombectomy in subacute or chronic disease is not well defined, with an inherent risk of distal embolization.
Avoiding Embolization, Dissection, and Rupture
Minimizing wire and catheter manipulation across a lesion at high risk for embolization, such as those that are heavily calcified with an irregular plaque or ulceration, is prudent and should dictate early intraoperative anticoagulation. In heavily calcified vessels, a low-profile, predilation balloon should be considered followed by primary stenting. Aggressive balloon dilation after stent placement may reduce the risk of embolization, because the stent traps potential embolic debris.
It is often difficult to avoid dissection in a heavily calcified iliac artery. Intravascular ultrasound (IVUS) may be used before dilation to confirm vessel diameter and lesion length, and thus reduce the potential for vessel rupture by assuring appropriate device sizing. Self-expanding rather than balloon-expandable stents also allow for a more controlled dilation, with covered stents permitting dilation in vessels at risk for rupture. If there is concern that vessel dilation is inadequate, IVUS may be used to confirm that an appropriate vessel diameter has been achieved. Pain may be noted with iliac angioplasty, but severe pain may be a sign of rupture.
Endovascular Technique
Aortic Occlusion
Sheath Placement
Antegrade recanalization is easier than retrograde traversal of a lesion, and access sites should be planned for the arm and both groins. Using a 4-Fr sheath, retrograde brachial artery access is obtained and the wire is manipulated through the descending thoracic and abdominal aorta to the point of occlusion. A flush aortogram is performed, including the abdomen and pelvis, with careful and extended imaging of the vessels beyond the occlusion to determine precisely where the vessel reconstitutes. A multi-purpose angled (MPA) catheter, such as one from Cook Medical (Bloomington, Ind.) or a straight catheter, such as a Quick-Cross (Spectranetics, Colorado Springs, Colo.), is then advanced to the level of the occlusion.
Crossing a Lesion
An angled Glidewire (Terumo Medical Corp., Somerset, N.J.) is manipulated through the occlusion “cap” using a drilling technique. This involves advancing the catheter to the level of the occlusion, with forward force maintained on the catheter to keep it in position, and then rapidly spinning the wire to “drill” through the occlusion, advancing the catheter as a pathway is created ( Fig. 31-1 ). The most difficult part of the occlusion to traverse is the proximal cap, which is often hard to penetrate. Once access through the cap is achieved, the surgeon can more easily advance the wire. After passing the wire and advancing the catheter through the occlusion, an intraluminal position is confirmed by removing the wire and noting blood return through the catheter. Pressure measurement through the catheter or a contrast injection is performed to assure luminal reentry. When crossing the lesion and reentering the true lumen of the aorta proves challenging, a combination of antegrade and retrograde access can be used to achieve through-and-through arm to groin access.
