The twist technique: a method to minimize wire prolapse during Bird's Nest filter placement.

PURPOSE: To determine whether a twist technique can help reduce the occurrence of fine-wire prolapse proximal to the hooks of the Bird's Nest filter in the inferior vena cava. MATERIALS AND METHODS: Abdominal radiographs were retrospectively analyzed after placement of filters with no twist (n = 100), with two 360 degree twists (n = 55), or with three 360 degree twists (n = 61). RESULTS: Prolapse of 5 mm or more was encountered in 32% of cases (32 of 100 cases) in which no twists were imparted. The average length of prolapse was 2.8 cm (range, 0.5-5.1 cm). The average length of the filter nest was 9.4 cm (range 5.1-13.6 cm). Use of two 360 degree twists reduced the rate of prolapse to 9.1% (five of 55 cases) (P < .005 vs no twist); the average length of prolapse was 2.8 cm (range, 0.6-6.4 cm). The average filter-nest length was reduced 7.5 cm (range, 4.0-13.3 cm). With three 360 degree twists, prolapse occurred in 4.9% of cases (three of 61 cases) (P < .005 vs no twist). The average length of prolapse was 2.6 cm (range, 0.7-4.8 cm). The average filter-nest length was 7.8 cm (range, 3.5-12.8 cm). The difference in prolapse frequency when two twists were used as opposed to three is not statistically significant. CONCLUSION: Application of two or three 360 degree twists to the catheter-sheath unit during insertion of the Bird's Nest filter produces a statistically significant reduction in the occurrence of wire prolapse.

The Bird's Nest Filter. An alternative to long-term oral anticoagulation in patients with advanced malignancies.

Thromboembolic complications are common in patients with advanced malignancies. For these patients anticoagulation with warfarin is often complicated by severe bleeding. For this reason we evaluated the safety and efficacy of the Bird's Nest Filter, a new device capable of preventing migration of thromboemboli to the pulmonary arteries through interruption of the inferior vena cava. We report a series of 31 unselected patients with advanced malignancies and thromboembolic disease in whom the filter was used in lieu of chronic full-dose warfarin anticoagulation. No documented cases of pulmonary emboli occurred after insertion of the filter. Placement of the filter was uncomplicated. Eight patients (25.8%) developed lower-extremity edema. Venous thrombosis distal to the filter was documented in six (19.4%) patients but did not require institution of heparin or warfarin. Two patients (6.5%) required treatment with aspirin for painful lower-extremity thrombophlebitis. No filter migration was documented. We conclude that the use of the Bird's Nest Filter is an option for patients with cancer-related lower-extremity thrombosis who are at risk for pulmonary emboli and are poor candidates for full-dose systemic anticoagulation with warfarin. A prospective randomized trial comparing the filter and the new strategy of low-dose anticoagulation with warfarin will be needed to completely validate this approach.

Left femoral vein approach for the percutaneous placement of the Bird's Nest Filter.

The Bird's Nest Filter femoral catheter set has proven to be too short in some patients to permit placement in close proximity to the renal veins via the left femoral vein approach. The use of the longer, but otherwise identical Bird's Nest Filter jugular catheter set via the left femoral vein eliminates this problem.

Use of the Bird's Nest filter in oversized inferior venae cavae.

An inferior vena cava (IVC) diameter of greater than 28 mm has been considered a contraindication to the intracaval placement of Greenfield, LG-Medical (LGM), and Simon nitinol filters, necessitating biiliac placement of these devices. With the Bird's Nest filter (BNF), the maximum span of the struts, which immobilize the device, is 60 mm; this allows the placement of the BNF in an oversized IVC having a diameter of greater than 28 mm. Over a 44-month period, 799 IVC filters (547 BNF, 136 Greenfield filters, and 116 LGM filters) were inserted. BNFs were placed in 18 patients (2.3%) with an oversized IVC (diameter range, 29-42 mm); all filters were placed via the femoral route. Patient records were reviewed to determine if problems were associated with filter insertion (including insertion site femoral vein thrombosis) and to determine the prevalence of filter migration, caval thrombosis, and new or recurrent pulmonary emboli (PE) after insertion. No difficulties were encountered during insertion. There was no documented case of device migration, caval thrombosis, or clinically apparent new or recurrent PE. The data suggest that the BNF is the filtering device of choice in patients with an oversized IVC.

Influence of preservation or perfusion of intraoperatively identified spinal cord blood supply on spinal motor evoked potentials and paraplegia after aortic surgery.

Permanent ligation of arteries supplying blood to the spinal cord in operations for aortic aneurysm can lead to spinal cord ischemia, which can result in either paraparesis or paraplegia. This report describes a rapid method of intraoperative identification of those arteries that supply the spinal cord by use of an intrathecal platinum electrode to detect hydrogen in solution that has been injected into the aortic ostia. Preservation or perfusion of those identified arteries supplying the spinal cord may decrease the rate of postoperative neurologic complications. Of 28 porcine experiments with postoperative observation for 24 hours, there were 3 initial pilot experiments in which saline saturated with hydrogen was injected into the temporarily cross-clamped aorta. Twenty animals were then randomized to (1) preservation of only the vessels sequentially identified to supply blood to the spinal cord from T-13 to L-5 (n = 10); (2) division of the vessels supplying the spinal cord (n = 10). A further five animals underwent perfusion experiments wherein the identified cord arteries were perfused by a shunt, the other nonsupply arteries were divided, and the aorta was kept clamped for 45 minutes. Spinal motor evoked potentials were elicited with an intrathecal electrode and were highly sensitive for paralysis. Paralysis occurred in 0/3 pilot (p less than 0.013 vs division); 8/10 division; 1/10 preservation (p less than 0.0017 vs division); and perfusion 1/5 (p less than 0.025 vs division). Results of a pilot study in eight humans shows that the technique can be used to rapidly identify segmental arteries supplying the spinal cord, to determine if distal perfusion is supplying the spinal cord with blood flow, and if reattached segmental arteries are patent.

MR imaging of the bird's nest filter.

The appearance of the Bird's Nest inferior vena cava filter on magnetic resonance (MR) images of 11 patients is described. No complication or symptomatic filter displacement was encountered as a result of MR imaging performed at 1.5 T. The filters created significant local artifact and distortion on MR images. However, diagnostic MR images of the pelvis, spine, and brain may still be obtained.

The bird's nest inferior vena cava filter: progress report.

The bird's nest inferior vena cava filter, in clinical trial since 1982, has been placed in 568 patients at risk for pulmonary embolism. Of the 481 patients in whom the filter had been in place for 6 months or more, 440 were followed up clinically. The prevalence of clinically suspected recurrent pulmonary thromboembolism was 2.7% (12 patients) and that of inferior vena cava filter occlusion was 2.9% (13 patients). With the initial filter design, filter migration occurred in five patients. No migrations have occurred in the 147 patients treated with the filter after its modification to improve the anchoring system for greater stability. The bird's nest filter has proved safe and effective in the prevention of pulmonary embolism.

The bird's nest filter: a new percutaneous transcatheter inferior vena cava filter.

The bird's nest filter is a new transvenous stainless steel inferior vena cava filter designed for percutaneous introduction. The filter design eliminates the technical problems associated with other transvenous filters and produces an effective nonthrombogenic barrier to potential pulmonary emboli.

Percutaneous transcatheter filter for the inferior vena cava. A new device for treatment of patients with pulmonary embolism.

A filter for the inferior vena cava has been devised for treatment of pulmonary embolism. Percutaneous insertion of the filter is accomplished with the use of a sheath and an 8-F catheter. Therapeutic results involving 28 patients have been excellent. No embolism has recurred; no vena cava thrombosis has developed. Since minor surgery is unnecessary, the procedure saves time and is cost-effective.

Extraction of chronically infected transvenous pacemaker leads: report of an unusual problem.

This is a report of a patient with an impacted, chronically infected transvenous pacemaker lead whose management was complicated by the presence of a functioning contralateral transvenous pacemaker. Treatment included sustained traction on the infected lead, a left subcostal thoracotomy for placement of new sutureless epicardial leads, and retrograde right iliac vein cannulation for final snare removal of the mobilized lead. The patient is currently free of infection, and has normal pacemaker function.

Neuroangiography with iohexol.

Iohexol is a new, nonionic water-soluble contrast agent undergoing early clinical trials in the United States. Using a double-blind, parallel format, iohexol was compared with meglumine iothalamate (60 patients) for selective cerebral angiography, and with sodium meglumine diatrizoate (40 patients) for arch aortography. Iohexol produced significantly less pain than meglumine iothalamate or sodium meglumine diatrizoate. There were no significant differences in terms of heart rate, blood pressure, or electrocardiogram (ECG) changes. Both produced a transient tachycardia and hypotension after arch aortography, but significantly less so with iohexol. No significant complications occurred. Film quality was comparable between contrast agents except for diminished motion artifacts with iohexol. Iohexol appears to be a superior neuroangiographic contrast agent to current ionic drugs.

Jejunoileal arteriovenous malformation: localization for resection by segmental bowel staining techniques.

Arteriovenous malformations, submucosal vascular lakes, of the jejunum and ileum which cause chronic gastrointestinal bleeding and anemia are easily identified before operation by selective arteriography but difficult at operation owing to lack of physical signs. This report is concerned with a patient who had such a lesion located in the proximal jejunum. The involved segment was easily identified at operation by injection of Indigo Carmine solution during operation into the involved jejunal artery subselectively catheterized immediately prior to operation. The duration of jejunal staining before resection was 45 minutes in this case and varied from 35 to 55 minutes in five other patients who had right colectomy for carcinoma, providing the opportunity to inject accurately in a conveniently located radiology suite before operation. Safe, convenient, longer periods of staining which could be performed at the time of original diagnosis were demonstrated in dog experiments using "biologic" colloidal carbon in which the bowel segment was well stained at the time of sacrifice five days after injection. There were no gross or microscopic signs of injury to bowel.

Fortuitous rupture of aortic aneurysm: a catastrophic event affording time for surgical cure.

The rupture of an aortic aneurysm is generally a fatal event, but occasionally the rupture will occur into an adjacent vascular structure, thereby preventing exsanguination and affording temporary survival. Three cases are presented illustrating the fortuitous nature of the rupture of an aortic aneurysm into a vascular structure. The first patient had an atherosclerotic abdominal aortic aneurysm that ruptured into the inferior vena cava and was successfully repaired. The second case demonstrates the formation of a fistula from the aorta to the left pulmonary artery in a patient with a syphilitic thoracic aortic aneurysm. In the third patient a dissecting aneurysm of the aortic root that communicated with the right ventricle after coronary bypass surgery was successfully repaired. Rarely, aortic aneurysms will rupture fortuitously into vascular capacitance structures. These three cases emphasize the need for early accurate diagnosis and the institution of appropriate surgical measures.

Progress in treatment of thoracoabdominal and abdominal aortic aneurysms involving celiac, superior mesenteric, and renal arteries.

This is a report of surgical treatment of thoracoabdominal aortic aneurysms and aneurysms of the abdominal aorta from which the visceral vessels arise during the 18 year period from April 5, 1960, to April 20, 1978. The extent of aneurysm is divided into five groups. Group I (10 patients) involved most of the thoracic and abdominal aorta down to celiac axis. Group II (22 patients) involved most of the thoracic and abdominal aorta distal to left subclavian artery. Group III (20 patients) were those with lesser involvement of the thoracic aorta and most of the abdominal aorta. Group IV (18 patients) with involvement of the entire abdominal aorta and Group V (12 patients) with involvement of lower abdominal aorta and renal arteries. Treatment in the majority of these cases was by graft inclusion technique with visceral vessel reattachment by direct suture of orifice to openings made in the graft. Intercostal and/or lumbar arteries were also reattached in some with the more extensive lesions. Aortic and renal artery occlusion times varied from 15 to 155 minutes. Paraplegia developed in five patients with the more extensive lesions but was reduced to one-third and made less severe by reattaching intercostal and lumbar arteries. Renal dysfunction was mild in four patients and severe in three patients after operation. All these were transient except one who died while recovering from renal failure. The latter cases were those difficult to reattach or were not initially successful and required reoperation. Of the 82 patients, 77 (94%) survived operation and long-term followup was obtained in 95% of cases, 23 performed over five years ago. Actuarial curves were constructed and compared to survival curves following simple infrarenal abdominal aortic resection. The survival rate both immediately and at six years, were the same.

Celiac axis, superior mesenteric artery, and inferior mesenteric artery occlusion: surgical considerations.

Occlusion of the celiac, superior mesenteric, and inferior mesenteric artery has been studied in 46 patients treated by operation. The condition was acute and was caused by embolic obstruction of the superior mesenteric artery in four cardiac patients and detachment of the inferior mesenteric artery in two patients during removal of infrarenal abdominal aortic aneurysms. The condition was chronic and involved two or all three of the vessels in 40 patient. Embolic obstruction caused severe abdominal pain but few physical signs early in the process,, but the picture of an acute abdomen indicating bowel gangrene developed in a few hours. Ischemia from inferior mesenteric detachment was observed at operation. Patients with chronic obstruction had abdominal pain, weight loss, and diarrhea. Patients with embolic obstruction were treated successfully by embolectomy, and patients developing intraoperative sigmoid ischemia were treated by reattachment of inferior mesenteric arteries to aortic graft. Various procedures were employed in patients with chronic multiple obstruction. However, graft bypass using Dacron tubing was preferable because of its simplicity and because the frequently (48%) associated occlusive disease and aneurysm of the distal aorta were treated at the same time. Confining operation to the abdomen significantly reduced the magnitude of operation and eliminated risks in this age group. Of the 46 patients, 91% survived and were relieved of their symptoms despite associated disease. The 5-year survival rate in this group of patients was 62%.

Angiographic and pathologic correlations of hepatic focal nodular hyperplasia.

Focal nodular hyperplasia of the liver has a distinctive gross appearance which includes a central fibrous zone containing vessels with a variety of abnormalities. When focal nodular hyperplasia is visualized arteriographically, an artery enters the lesion, branches, and supplies the mass centrifugally. It is likely that the central fibrous zone is the area from which the these branches originate. Nodular hyperplasia is not a life-threatening lesion, except in women taking oral contraceptives who may have massive hemorrhage. If an asymptomatic lesion of the liver has the distinctive arteriographic centrifugal filling pattern of nodular hyperplasia, resection is not recommended as long as oral contraceptives are not used.