Endovascular management of acute extensive iliofemoral deep venous thrombosis caused by May-Thurner syndrome.

PURPOSE: The authors report their experience on the treatment of acute extensive iliofemoral deep venous thrombosis (DVT) due to May-Thurner syndrome using endovascular techniques. MATERIALS AND METHODS: During a 1-year period, 10 symptomatic women (age range, 22-52 years; mean, 35.5 years) were referred for treatment. After ascending venography, an infusion catheter system was placed and urokinase was infused locally into the thrombus burden. After near complete clot dissolution (> or = 95%) or lytic stagnation, the residual left common iliac vein narrowing was treated by means of angioplasty and/or placement of Wallstent endoprosthesis. All patients continued to receive oral warfarin. Patients were followed-up by means of clinic visits, and stent patency was assessed by means of duplex Doppler sonography performed at 1, 3, 6, and 12 months, and then yearly thereafter. RESULTS: The total dose of urokinase used and the duration of infusion were 5.87 +/- 2.57 million units (range, 3.18-10.7) and 51.95 +/- 21.57 hours (range, 26.5-89), respectively. After completion of thrombolytic therapy, the iliac vein narrowing was successfully treated by deployment of a Wallstent endoprosthesis in all 10 patients because of failure of angioplasty. No major bleeding complications occurred. Initial clinical success was 100%, with complete resolution of symptoms in all patients. One patient, who was hypercoagulable and was receiving chemotherapy for metastatic adenocarcinoma, had recurrent symptomatic acute DVT 1 month after therapy. She underwent successful repeated lysis. The remaining nine patients were asymptomatic, with a mean follow-up of 15.2 months (range, 6-36 months). One asymptomatic patient, at 36-month follow-up ultrasound, had iliac vein occlusion and well-developed venous collaterals. Serial ultrasonography in all 10 patients showed no evidence of valvular insufficiency in the femoral and popliteal veins. CONCLUSION: Catheter-directed thrombolytic therapy for the treatment of acute extensive iliofemoral DVT due to May-Thurner syndrome is an effective method for restoring venous patency and provides relief of the acute symptoms. The underlying left common iliac vein lesion invariably needs to undergo stent placement.

New hemodynamic test for assessment of failing hemodialysis grafts: the saline infusion test.

PURPOSE: To validate the saline infusion test, a new hemodynamic test for assessment of failing hemodialysis access grafts. MATERIALS AND METHODS: Over a 12-month period, 31 procedures were performed in 25 patients with synthetic forearm loop grafts for hemodialysis. Pre- and postangioplasty measurements of static graft pressures and infusion pressures were obtained. For the saline infusion test, graft pressure was measured while saline was infused at a rate of 600 mL/min for 10 seconds with arterial inflow occluded. Comparison was made to percent outflow stenosis as determined with pre- and postangioplasty angiograms. RESULTS: There was no correlation between either the static intragraft pressure (r = .085, P = .654) or the normalized pressure ratio (r = .136, P = .4676) and venous outflow stenosis in the preangioplasty group. When pressure was measured during infusion, a significant Pearson correlation was observed between infusion pressure and percent of angiographic stenosis (r = .60, P = .0002). All three pressure tests were significantly correlated to the percent stenosis identified after angioplasty. CONCLUSIONS: Pressure measured in the graft during the saline infusion test at a standard rate that simulates optimal graft flow correlates with the angiographic degree of stenosis and warrants further investigation as a useful adjunct to the assessment of revascularization results.

Safety of short stay observation after peripheral vascular intervention.

PURPOSE: To determine whether short observation periods (less than or equal to 4 hours) are safe in outpatients undergoing arterial peripheral vascular interventions. MATERIALS AND METHODS: A retrospective review of 203 patient medical records from the Interventional Vascular Department for 239 lower extremity or abdominal procedures (161 men and 78 women) during a 5-year period was completed. The average patient age was 62.2 years (range, 32-83 years). Thirty-six patients had more than one procedure. Indication, intervention, coagulation status, complication rate, and hospitalizations within 7 days after discharge from the short stay unit (SSU) were reviewed and the outcome was measured. Patients were grouped according to the length of their observation period (< or =4 hours or >4 hours) for statistical analysis. RESULTS: In 85% of the procedures (204 procedures), claudication was the primary indication for intervention. Angioplasty (203 procedures) was also commonly performed. Ninety procedures (38%) required stent placement, and other interventional procedures performed were pulse-spray thrombolysis (eight procedures), atherectomy (two procedures), and stent-graft placement (one procedure). None of the patients required hospitalization as a result of their radiologic intervention within 7 days after discharge from the SSU. Specifically, there were no major "at home" complications in patients discharged after an observation period of < or =4 hours. Two patients were admitted for outpatient procedures and were subsequently hospitalized as a result of a complication from the procedure. The complication rate (including minor complications) was 8% (seven of 87) in the < or =4 hour observation period group compared with 24.3% (37 of 152) in the >4 hour group (P < .01). This difference was due to a greater number of minor hematomas in the >4 hour group. CONCLUSION: Based on the authors' findings, many interventional vascular procedures can be performed safely on an outpatient basis with relatively short observation times. Early discharge from the SSU did not result in an increased readmission rate to the hospital because of delayed complications.

Synthetic dialysis shunts: thrombolysis with the Cragg thrombolytic brush catheter.

PURPOSE: To evaluate the effectiveness of the Cragg thrombolytic brush catheter for declotting of synthetic arteriovenous dialysis shunts. MATERIALS AND METHODS: In this randomized controlled trial, 77 patients with synthetic forearm loop shunts that were thrombosed were randomly assigned to undergo pharmacomechanical thrombolysis with a pulsed spray (n = 34) or a thrombolytic brush catheter (n = 43). The following findings were evaluated: declotting time, urokinase dose, procedure time, complications, and shunt patency at the first dialysis session and at 3 months. All data were collected prospectively in an unblinded manner. RESULTS: The total amount of urokinase used, including secondary interventions, was 243,657 IU with the catheter versus 476,563 IU with the pulsed spray (P = .001). At 15 minutes, clot lysis was successful in 66% of the patients with the catheter versus in 19% with the pulsed spray (P = .001). At 30 minutes, clot lysis was successful in 98% with the catheter versus 47% with the pulsed spray (P = .001). Procedure complication rates and patency at 3 months were similar for the catheter and the pulsed-spray groups. CONCLUSION: Use of the Cragg catheter with urokinase offered faster and more complete clot lysis than did use of the pulsed spray with urokinase. The amount of urokinase used with the catheter was half that used with the pulsed spray. Shunt patency at 3 months was similar for the two treatment methods.

New thrombolytic brush catheter in thrombosed polytetrafluoroethylene dialysis grafts: preclinical animal study.

PURPOSE: To assess the safety, efficacy, endothelial changes, and risks of pulmonary embolic events after the use of a new thrombolytic brush catheter in mature thrombosed polytetrafluoroethylene (PTFE) dialysis grafts in an animal model. MATERIALS AND METHODS: Loop configuration PTFE grafts were implanted in the femoral vessels of 12 canines 4 weeks before mechanical thrombosis was performed. The thrombus was allowed to consolidate for 24 hours in 10 animals, 72 hours in one animal, and 7 days in one animal. Standard percutaneous criss-cross catheter access was performed, and a soft, low-speed, brush (6 mm in diameter), aided by 250,000 U of periprocedural urokinase, was utilized for thrombolysis. The native vessels, just distal to the anastomosis, and lungs were evaluated macro- and microscopically. RESULTS: Thrombolysis was complete in all grafts with the exception of a small segment between the crossing of the access vascular sheaths. The total thrombolysis time ranged from 8 to 12 minutes; this included 5 minutes of pulse-spray lacing. No difference in thrombolysis time was found with regard to the age or amount of thrombus. Minimal endothelial changes were noted and no evidence of acute pulmonary embolus was found on necropsy or histologic studies. CONCLUSION: This method offers a simple, safe, and efficient means of recanalization of thrombosed PTFE dialysis grafts in this canine model.

Occlusive and aneurysmal peripheral arterial disease: assessment of a stent-graft system.

PURPOSE: To assess the use of a recently developed stent-graft system for treatment of occlusive lesions and aneurysms in the iliac and femoropopliteal arteries. MATERIALS AND METHODS: The stent-graft consisted of a nitinol stent framework covered by a thin-walled polyester fabric. The device was used in 105 patients with symptomatic peripheral vascular disease. Implant locations were iliac artery (n = 38), femoral artery (n = 62), and popliteal artery (n = 5). RESULTS: Initial technical success was achieved in all patients except one with occlusive disease and one with aneurysmal disease. Residual stenosis after stent-graft implantation was 0.5% +/- 3. Mean ankle-brachial index increased from 0.53 to 0.98. Complications were hematoma (n = 3), pseudoaneurysm (n = 2), puncture site thrombosis (n = 1), early graft thrombosis (n = 8), graft misplacement (n = 1), distal embolization (n = 2), delayed thrombosis (n = 14), pain and fever (n = 27). At the iliac level, primary patency was 97% and secondary patency was 100%. At the femoral level, primary patency was 59% and secondary patency was 81%. CONCLUSION: Endoluminal bypass with a percutaneously delivered stent-graft is feasible. Technical results are good, and the number of complications is few at the iliac level. At the femoropopliteal level, patency is not as good and the number of complications is higher.

Abdominal aortic aneurysms: preliminary technical and clinical results with transfemoral placement of endovascular self-expanding stent-grafts.

PURPOSE: To evaluate treatment of infrarenal abdominal aortic aneurysm (AAA) with a new endoluminal stent-graft. MATERIALS AND METHODS: In 26 male patients, straight or bifurcated nitinol stents covered with woven Dacron graft material were implanted to treat eccentric saccular AAA (n = 3) or AAA involving the bifurcation and common iliac arteries (n = 23), with follow-up from 8 days to 8 1/2 months. RESULTS: Implantation was technically successful in all but one of the 26 (96%) patients (leak of the stent-graft for more than 3 months necessitated implantation of an additional covered stent). In seven of the 26 patients, minor residual perfusion persisted immediately after implantation, but complete thrombosis occurred within 7 days. Five procedure-related complications occurred: distal embolization (n = 2); local hematoma, which necessitated surgery (n = 1); acute hepatic failure due to gastric bleeding, in a patient with liver cirrhosis (n = 1); and stent-graft occlusion due to emboli originating from the left atrium (n = 1). CONCLUSION: Exclusion of AAA from circulation was feasible, safe, and clinically effective with the new stent-graft.

[Endoluminal therapy of infrarenal abdominal aortic aneurysms: a new interventional technique]. / Die endoluminale Therapie des infrarenalen Bauchaorten-aneurysmas--ein neues interventionelles Verfahren.

PURPOSE: With a series of 31 transluminal stent-graft procedures, we assessed the feasibility and clinical effectiveness of a new stent-graft for the treatment of infrarenal abdominal aortic aneurysms (AAAs). METHODS: We treated the patients (male; mean age 71 years) with straight or bifurcated nitinol stents covered with woven dacron graft material for infrarenal eccentric saccular AAA (n = 4) or AAA involving the bifurcation and the common iliac arteries (n = 27). The 18-F delivery system was advanced via a surgical arteriotomy and the stent-graft was placed under fluoroscopic control. Follow-up period ranged from 8 days to 9 months. RESULTS: The implantation of the stent-grafts was technically successful in 30/31 cases. Procedure-related complications were acute hepatic failure due to gastric bleeding in a patient with liver cirrhosis, graft occlusion due to emboli originating from the left atrium (n = 1), macro-embolisation (n = 3), local haematoma (n = 1) and av-fistula (n = 1) requiring surgery. A post-implantation syndrome with leukocytosis and elevated C-reactive protein was observed in all patients. CONCLUSIONS: Endoluminal repair of infrarenal AAA with use of dacron covered nitinol stent-grafts is feasible, safe and clinically effective. However, careful long-term evaluation is necessary.

A retrievable nitinol vena cava filter: experimental and initial clinical results.

PURPOSE: The authors describe the properties of a new retrievable nitinol vena cava filter and report experimental and initial clinical results. MATERIALS AND METHODS: The filters, made of nitinol monofilament wire that forms a spiral cone and retrieval wire, were introduced through an indwelling 5.5-F transfemoral sheath into the infrarenal portion of the inferior vena cava in 10 sheep. In seven animals, four 4 x 30-mm radiopaque clots were injected below the filter to test its thrombus-trapping efficacy. Aspiration thrombectomy was then attempted, and the filter was removed. Follow-up venography was performed 1 week after placement in three other animals. After successful preclinical testing, the filter was implanted and retrieved in two patients. RESULTS: All 10 filters were successfully and easily placed in sheep. All filters were thrombus-free at follow-up venography. All clots injected in the iliac veins were trapped by the filter and successfully removed by means of aspiration thrombectomy. All 10 filters were retrieved without difficulty. Temporary filter implantation and retrieval were accomplished in two patients for 5 and 7 days. In one patient, infrafilter thrombus was aspirated. Perisheath thrombosis occurred in both patients. One patient subsequently underwent permanent filter placement. CONCLUSION: Temporary vena cava filtration is feasible. Potential advantages include easy placement, surveillance, and retrieval. One current limitation is pericatheter thrombosis, which may be eliminated by a less thrombogenic sheath.

Iliac artery stent placement: clinical experience with a nitinol stent.

PURPOSE: To determine the effectiveness of a prototype nitinol stent in the iliac arteries. MATERIALS AND METHODS: Fourteen patients with arteriosclerotic lesions of the iliac arteries (nine stenoses, five occlusions) were treated percutaneously with a prototype nitinol vascular stent (Cragg stent) after unsuccessful percutaneous transluminal angioplasty. RESULTS: In 13 patients available for follow-up, the mean ankle-brachial index (ABI) increased from 0.4 +/- 0.32 (standard deviation) before the procedure to 0.81 +/- 0.27 after the procedure (P < .01). After 6, 12, and 24 months, the mean ABI was 0.97 +/- 0.2, 0.87 +/- 0.15, and 0.89 +/- 0.1, respectively. In two patients, radial stiffness of the stent was too low to completely eliminate a high-grade, calcified stenosis; long-term patency of the vessel, however, was preserved. In all other patients, stent placement achieved good vascular reconstitution. No stent occlusion or restenosis was observed. CONCLUSION: The results with the Cragg stent were similar to those with other commercially available stents. These preliminary results require confirmation with a larger series.

Nitinol intravascular stent: results of preclinical evaluation.

PURPOSE: To test an expandable nitinol intraluminal stent for hoop strength, biocompatibility, corrosion resistance, and patency. MATERIALS AND METHODS: Forty-four stents were implanted in the iliac arteries of 22 sheep. Follow-up was performed with angiography and histologic examination for up to 6 months. RESULTS: All but one stent remained widely patent during the follow-up period. Two stents in two sheep were placed incorrectly early in the study; these sheep were not followed up. Hoop strength was found to be superior to that of a similar, commercially available, self-expanding stent. Minimal corrosion was seen at 6 months, and the stent appears to be biocompatible. The stent has good radiopacity and deploys with minimal foreshortening. CONCLUSION: The stent can be reliably and safely deployed in the vascular system. Clinical trials in humans are warranted.

Percutaneous femoropopliteal graft placement.

PURPOSE: Femoropopliteal bypass surgery is now recommended for the treatment of long-segment or diffuse superficial femoral artery disease. The authors describe a technique for percutaneous placement of a prosthetic femoropopliteal graft. PATIENTS AND METHODS: The technique has been accomplished with conventional polytetrafluoroethylene graft material and a variety of implantation techniques in eight patients. RESULTS: Technical success was achieved in all patients who underwent graft placement. Grafts up to 28 cm in length were placed, and graft patency was demonstrated up to 10 months after implantation. Six of the eight patients were asymptomatic during the follow-up period; one patient who had symptoms during this time underwent thrombolysis and redilation of the distal stent, and the symptoms resolved. In the other patient with symptoms, the procedure failed clinically because of poor runoff. CONCLUSION: This study demonstrates the feasibility of percutaneous graft placement in the femoral artery, but durability must be established in relation to traditional bypass surgery before it can be recommended on a wider scale.

Percutaneous femoropopliteal graft placement.

Femoropopliteal bypass surgery is now recommended for the treatment of long-segment or diffuse superficial femoral artery disease. The authors describe a technique for percutaneous placement of a prosthetic femoropopliteal graft. The technique has been accomplished with conventional polytetrafluoroethylene graft material and a variety of implantation techniques. Technical success was achieved in eight patients who underwent graft placement. Grafts up to 28 cm in length were placed, and graft patency was demonstrated up to 6 months after implantation. Six of the eight patients were asymptomatic during the follow-up period; one patient who had symptoms during this time underwent thrombolysis and redilation of the distal stent, and the symptoms resolved. This study demonstrates the feasibility of percutaneous graft placement in the femoral artery, but durability must be established in relation to traditional bypass surgery before it can be recommended on a wider scale.

Management of infrainguinal occluded vein bypasses with a combined approach of thrombolysis and surveillance. A prospective study.

Intra-arterial thrombolysis with urokinase was attempted on 23 occluded infrainguinal vein bypasses. Lesions revealed by thrombolysis included 11 anastomotic stenoses, five midbypass stenoses, five native artery stenoses, and five unusable diffusely stenotic vein conduits. Adjunctive procedures performed immediately after successful thrombolysis included 10 local surgical revisions, five balloon angioplasties, and five new vein bypasses. Three nonanastomotic vein bypass stenoses and two common iliac artery stenoses were detected using a surveillance protocol in subsequent follow-up of patients with patent bypasses. Twelve-month patency following thrombolysis (including immediate failures) was 52.4%. The use of thrombolysis in the management of occluded vein bypasses allows the identification and correction of pathological lesions. Once revised, continued vein bypass patency may be improved with a surveillance program.

Effect of antineoplastic agents on smooth muscle cell proliferation in vitro: implications for prevention of restenosis after transluminal angioplasty.

The effect of several antineoplastic agents on vascular smooth muscle cell proliferation was studied in vitro. Both fluorouracil and cytarabine produced significant concentration-dependent inhibition of smooth muscle cell proliferation in cultured porcine pulmonary artery in vitro, while cyclophosphamide stimulated growth. For fluorouracil, inhibition was near maximal at a concentration of 13.0 microgram/mL and was seen with both coincubation and 2-hour preincubation of fluorouracil with quiescent cells. Fluorouracil is a promising agent for inhibition of intimal proliferation. Further work is warranted to determine its effect in vivo.

Comparison of the efficacy of digital subtraction and film-screen angiography of the lower limb: prospective study in 50 patients.

We prospectively compared current digital subtraction angiography (DSA) with conventional film-screen angiography (FSA) of the lower limb for evaluation of areas of arterial stenosis and degree of arterial visualization. Fifty patients had both DSA and FSA of a single lower limb. Specific anatomic sites (examiner-selected sites) throughout the lower limb were marked on each film by an experienced angiographer (examiner). These sites consisted of the common femoral, superficial femoral, popliteal, anterior tibial, posterior tibial, peroneal, and dorsalis pedis arteries and bypass grafts, when present. The films were then reviewed blindly by two different experienced angiographers (observers). All sites were graded for the degree of arterial narrowing based on a standard scale (grade 1 = normal, grade 5 = occluded) that also included grading for nonvisualization (grade 6). Each observer also selected the most stenotic site in each anatomic area (observer-selected sites). The data were analyzed for the entire lower limb and at specific anatomic sites. DSA sites were judged to be slightly more narrowed (p less than .05) in the superficial femoral artery by both observers and in the common femoral artery, bypass graft, and overall by a single observer. No other significant differences were found in grade of stenosis or vessel visualization for examiner-selected sites. For observer-selected sites, observers agreed on the location of the most stenotic site 76% of the time for FSA and 69% of the time for DSA. No significant difference was found in grade of stenosis or vessel visualization for either observer for the entire lower limb or at specific anatomic sites. These findings were present when all sites chosen were considered and when there was agreement between sites chosen on FSA and DSA for each observer. In conclusion, optimal-quality FSA and DSA produced virtually equivalent results for angiography of the lower limb for both grade of stenosis/occlusion and vessel visualization.

Randomized double-blind trial of midazolam/placebo and midazolam/fentanyl for sedation and analgesia in lower-extremity angiography.

Safety and efficacy of two drug regimens used for sedation and analgesia during lower-extremity angiography were studied. Midazolam (loading dose 14.5 micrograms/kg; maintenance dose, 7.2 micrograms/kg) with or without fentanyl (loading dose, 0.725 micrograms/kg; maintenance dose, 0.362 micrograms/kg) was administered in a blind fashion as an IV bolus to 50 patients. Hemodynamic responses were monitored, and a standardized questionnaire was given to the patient before, immediately after, and 8-24 hr after the procedure. Physicians also were asked questions after the procedure. Heart rate and oxygen saturation were not significantly different before and 2 min after administration or between groups. A small but significant decrease in blood pressure occurred 2 min after the loading dose was given in both groups. Both drug regimens had statistically significant anxiolytic effects; however, anxiolytic effects were superior in the midazolam/fentanyl group (p less than .02). Patients rated the overall effectiveness of anesthesia with midazolam/fentanyl as superior (p less than .02). Analysis of physicians' judgments of the effectiveness of sedation and analgesia showed a statistically significant advantage for the midazolam/fentanyl group (p less than .01). We conclude that midazolam/fentanyl appears to be as safe as and more efficacious than midazolam alone for sedation and analgesia during lower-extremity angiography.