Aortoiliac Interventions for Occlusive Disease

Introduction

Endovascular treatment of complex (TASC C and D) lesions of the aortoiliac arteries has been increasingly adopted since the early 2000s, especially after the introduction of stent grafts. Although the primary patency rates are reported to be 60%–86% at 5 years, which is lower than with direct revascularization, secondary patency rates are comparable ranging from 80% to 98%. In the most recent meta-analysis, the 5-year patency rates were reported to be 91% in patients with claudication and 87% in patients with critical limb ischemia. Mortality and morbidity were 3.3% and 8.3%, which is the main reason for adopting minimally invasive alternatives. There are no modern studies comparing direct revascularization with endovascular revascularization in patients with complex aortoiliac occlusive disease in large numbers; however, a few small series have explored this issue. Overall, they have shown that endovascular treatment has inferior primary patency with similar secondary patency rates and lower morbidity and mortality.

In contrast to outcomes in the femoropopliteal segment, patency of TASC C and D lesions in the iliac segment has been reported to be comparable with that of TASC A and B lesions. In a series of 433 patients who had systematic iliac stenting between 1997 and 2009, with a median follow-up of 72 months, primary patency rates at 5 and 10 years were 83% and 71%, respectively, in the TASC II C/D group and 88% and 83% in the TASC II A/B group ( P =0.17). However, the risk of complications (vessel rupture, dissections, loss of branch vessels, early and late occlusions, distal embolization) increased with the complexity of the revascularization. The complication rate was higher in the C/D group (9% versus 3%, P =0.014), with significantly longer procedure times in the above referenced study.

The most important aspect of aortoiliac revascularization is to anticipate and to avoid complications via careful preoperative planning. In addition to obtaining a detailed history and physical examination, any patient with suspected aortoiliac occlusive disease should undergo preoperative imaging, ideally with a computed tomography angiogram. The amount of calcium and clot content within the vessels, the anatomy of the critical vessels, and the anticipated re-entry level are all crucial to planning treatment of these lesions. However, despite appropriate planning, complications will occur and, in that event, timely and appropriate management can minimize adverse outcomes.

Patient Preparation

Management of aortoiliac disease often requires a combination of both open and endovascular techniques. While many complex lesions can be addressed percutaneously, a significant proportion of patients (up to 20%) have bulky common femoral artery disease and will require concomitant femoral endarterectomy. Open access may also be preferred in the setting of acute or subacute occlusion, as it facilitates protection from distal embolization. In addition, antegrade iliac crossing may result in a common femoral dissection, which is typically managed via open repair. If open femoral intervention is either likely or anticipated, the procedure should be performed in a setting appropriate for a hybrid repair.

Crossing aortoiliac lesions can be performed in either a retrograde or antegrade fashion and it is not unusual to need a combination of both approaches. Therefore, the possibility of both brachial and femoral access should be anticipated, and the patient should be prepared accordingly at the beginning of the procedure. Upper extremity access typically requires a sheath at least 90 cm in length. However, longer sheaths and crossing catheters up to 125 cm should be available for taller patients or in the event that a radial approach is preferred. When crossing via a contralateral femoral approach, a deflectable sheath may be necessary to increase support, especially when dealing with a short common iliac stump.

In the rare event that an aortoiliac lesion cannot be crossed, there should be a clear plan for open intervention. If revascularization is urgent, the patient should be prepared for possible femoral–femoral or axillary–femoral bypass at the beginning of the procedure.

Crossing and Treating Aorto-Iliac Lesions

There are four main issues to address when planning an endovascular intervention for aortoiliac lesions: (1) antegrade versus retrograde crossing; (2) femoral versus brachial access; (3) re-entry method; (4) stent selection. Of these, the crossing direction is the most important as it will, in many respects, dictate each of the subsequent choices. However, every decision is ultimately predicated on the desire to minimize the risks of vessel perforation, embolization, and occlusion associated with a difficult re-entry.