Chapter 11 Intensive Care Unit

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SECTION 1 • Techniques and Methods in Critical Care

extremity, mesenteric, or renal systems may often be effectively relieved by thrombus extraction (e.g., stroke) or by stenting, as may symptoms that persist despite optimal medical management. In advanced centers, quite sophisticated manipulations, such as aortic stent graft reconstruction, realignment of true lumen flow, and fenestration, can be success- fully accomplished. Traumatic aortic injuries (e.g., pseudoaneurysm, minimal intimal tear, flow-limiting lesions) are evaluated and perhaps better addressed with less morbidity than open surgical repairs. The same principle of endovascular stent graft repair often (but not invariably) is feasible for ruptured thoracic or abdominal aortic aneurysm. These IR procedures carry lower morbidity than invasive surgery and are usually possible, assuming that the anatomy is favor- able and the procedure is undertaken emergently. Symptomatically, ischemic smaller vessels of the brain, extremities, and mesentery can also be stented effectively, assuming such preconditions are met. Venous Thrombosis IR has been rapidly developing a useful role for both submassive and massive venothrombosis. IR should be engaged early for consultation regarding catheter- based lytic infusions into the pulmonary artery or thrombectomy when standard medical management

fails and/or systemic fibrinolysis is contraindicated. The appropriate place of temporary prophylaxis by IVC filter has been clarified recently but not entirely resolved (see below and Chapter23). All but a few of the newer filtering devices are approved for permanent placement despite their option for catheter-based removal (Fig. 11-28). Most if not all of present day filters are MRI compatible. At least one of the latest filter options (VenaTech [B. Braun Interventional Systems Inc. Bethlehem, PA, USA]) is convertible over the short term from filtering to nonfiltering functions. With these improved features, the indications for IVC filters include patients with known VTE at high risk from anticoagulation and those failing such therapy. Perioperative patients with VTE or long bone and pelvic fractures often are candidates, as are those postendovascular thrombolysis/thrombec- tomy with residual deep vein thrombosis. Patients who are immobilized with precarious cardiopulmo- nary compensation who would not be expected to withstand recurrent embolism are often considered. Interventional radiology now performs essential functions for early stroke (e.g., mechanical throm- bectomy) and for intracranial hemorrhage evalu- ation and management. These services include diagnosis and treatment of vascular anomalies,

FIGURE 11-28. One of many types of IVC filter (VenaTech). After the high-risk period for embolism has passed, the core can be snared by its hook and removed. This allows the cage to remain permanently in place, acting as a stent rather than an occlusive obstruction.