The Greenfield Vena Cava Filter: Indications and Discussion
Indications and Discussion
No technique can be evaluated without establishing an “ideal” standard. In our view, such an ideal caval interruptive approach would incorporate the following features: (1) The procedure should be applicable with safety and efficacy by physicians of reasonable skill after modest periods of training. (2) The procedure should be performed without general anesthesia and with minimal patient invasion. (3) The approach should not interfere, acutely, with caval blood flow to a significant degree. (4) All potential emboli above a defined size (eg, 2 mm diameter) should be prevented. (5) Acute and chronic complications of the procedure (eg, bleeding, caval thrombosis) should be minimal. (6) The approach should be applicable despite concurrent anticoagulant or thrombolytic therapy. (7) The interruption should be reversible. alta white teeth whitening
Except for its use with thrombolytic therapy (for which there are few data) and the current permanency of its insertion, the Greenfield filter appears to approximate these ideal goals. As experience with the device has widened and the initially favorable reports concerning safety, caval patency, etc, have been confirmed, indications for insertion have understandably been liberalized. Early use was confined to patients with known DVT/PE and either complications from, or contraindications to anticoagulation; and to patients who experienced recurrent pulmonary embolism despite anticoagulant therapy. An excellent analysis of these indications has been published. Many authors have since argued for a wider use of the device. Of the cases presently reviewed, the indications for insertion were as follow: anticoagulation (AC) contraindicated, 154 (34 percent); failure of AC, 130 (29 percent); complication of AC, 66 (15 percent); prophylactic placement, 72 (16 percent); other, 30 (6 percent).
We routinely insert this filter in patients undergoing pulmonary thromboendarterectomy for pulmonary hypertension due to chronic proximal pulmonary artery clot. These patients now number over 30. Despite the high intracaval pressures often present in these patients and the common use of heparin, no significant complications have occurred. We have been gratified to see resolution of venous stasis problems postoperatively in some patients as their venous pressures return to normal, despite the presence of the filter. Because of the nature of the underlying disease, we make an effort to maintain all such patients on longterm anticoagulation. There have been no caval thromboses, and no embolic recurrences.