Bart L. Dolmatch

Comparison of the AngioJet Rheolytic Catheter to Surgical Thrombectomy for the Treatment of Thrombosed Hemodialysis Grafts

PURPOSEnTo compare the clinical effectiveness of the AngioJet F105 rheolytic catheter to that of surgical thrombectomy for the treatment of thrombosed hemodialysis grafts.nnnMATERIALS AND METHODSnThis was a multicenter, prospective, randomized trial comparing technical success, primary patency, and complication rates. A total of 153 patients were enrolled: 82 patients in the AngioJet group and 71 patients in the surgical thrombectomy group. Patient follow-up was performed 24-48 hours, 1 month, and 6 months after the procedures.nnnRESULTSnTechnical success, as defined by the patients ability to undergo hemodialysis treatment, was 73.2% for the AngioJet group and 78.8% for the surgical thrombectomy group (P = .41). The primary patency rates of the AngioJet group were 32%, 21%, and 15% at 1, 2, and 3 months, respectively. The primary patency rates for the surgical group were 41%, 32%, and 26% at 1, 2, and 3 months, respectively. This difference approached statistical significance (P = .053). The groups had similar complication rates-14.6% in the AngioJet group and 14.1% in the surgery group-although the surgery group had more major complications (11.3%). In the AngioJet group, there was a transient increase in plasma-free hemoglobin, which normalized within 24-48 hours.nnnCONCLUSIONSnThe AngioJet F105 catheter provides similar clinical results when compared to surgical thrombectomy for the treatment of thrombosed hemodialysis grafts. The difference in patency rates between these two techniques approached statistical significance. In addition, results of both thrombectomy methods were inferior to those suggested by the Dialysis Outcomes Quality Initiative guidelines.

Rheolytic thrombectomy in the treatment of acute limb-threatening ischemia: Immediate results and six-month follow-up of the multicenter AngioJet® registry

We tested the efficacy of rheolytic thrombectomy in treating 21 patients (mean age 68+/-12 years; 66% male) and 22 vessels (limbs) who presented to the hospital within 2 weeks of the development of limb-threatening ischemia. Fifty-two percent had contraindications to use thrombolytics, and 57% had severe comorbidities. All of the vessels were occluded with thrombus on the initial angiogram. Procedural success was achieved in 20 limbs (91%). Three patients expired in the hospital, and one expired at follow-up due to nonvascular causes. Acute limb salvage was achieved in 18 of 19 limbs (95%) in the 18 survivors, and 6-month limb salvage was achieved in 16 of 18 limbs (89%) in the 17 survivors. Rheolytic thrombectomy is effective in restoring immediate blood flow in acute limb-threatening ischemia, especially in high-risk surgical patients or patients with contraindications to thrombolytic therapy.

Treatment of Type II Endoleaks with Onyx

Endoleaks are defined as persistent perfusion of an abdominal aortic aneurysm (AAA) after endovascular stent-graft deployment. The authors describe their experience treating six endoleaks with the liquid embolic agent Onyx (ethylene-vinyl-alcohol copolymer). Complete endoleak occlusion was achieved in five of six cases. Follow-up imaging has demonstrated decreased aneurysm diameter in all patients 7-29 weeks (mean = 19.2 weeks) after treatment.

Renal Artery Stent Placement for the Management of Ischemic Nephropathy

PURPOSEnTo evaluate the angiographic and clinical results of percutaneously implanted renal artery endoprostheses (stents) for the treatment of patients with ischemic nephropathy.nnnMATERIALS AND METHODSnDuring a 52-month period, 45 patients with azotemia (serum creatinine > or = 1.5 mg/dL) and atheromatous renal artery stenosis untreatable by, or recurrent after, balloon angioplasty were treated by percutaneous placement of Palmaz stents. Stent implantation was unilateral in 32 cases and bilateral in 11 cases. Clinical results were determined by measurements of serum creatinine and follow-up angiography. Clinical benefit was defined as stabilization or improvement in serum creatinine level. Angiographic patency was defined as less than 50% diameter recurrent arterial stenosis.nnnRESULTSnStent placement was technically successful in 51 of 54 (94%) renal arteries. Technical failures were stent misdeployment requiring percutaneous stent retrieval (n = 2) and inadvertent placement distal to the desired position (n = 1). Complications included acute stent thrombosis (n = 1) and early initiation of hemodialysis (within 30 days; n = 1). There were two periprocedural deaths. With use of life-table analysis, clinical benefit was seen in 78% of patients at 6 months (n = 36), 72% at 1 year (n = 24), 62% at 2 years (n = 12), and 54% at 3 years (n = 3). In patients with clinical benefit, average creatinine level was reduced from 2.21 mg/dL +/- 0.91 before treatment to 2.05 mg/dL +/- 1.05 after treatment (P = .018). Lower initial serum creatinine level was associated with a better chance of clinical benefit (P = .05). No other variables affected outcome, including patient age, sex, diabetes, implanted stent diameter, unilateral versus bilateral stent placement, or ostial versus nonostial stent positioning. Conventional catheter angiography or spiral computed tomographic (CT) angiography performed in 19 patients (28 stents) at a mean interval of 12.5 months demonstrated primary patency in 75%. Maintained stent patency appeared to correlate with renal functional benefit.nnnCONCLUSIONSnPercutaneous renal artery stent placement for angioplasty failures or restenoses provides clinical benefit in most patients with ischemic nephropathy.

Patency and Tissue Response Related to Two Types of Polytetrafluoroethylene-Covered Stents in the Dog

PURPOSEnA canine model was used to determine tissue response related to placement of two different designs of polytetrafluoroethylene (PTFE) covered stents in the peripheral vascular system.nnnMATERIALS AND METHODSnTwo types of PTFE covered stents were implanted in the iliac arteries of 15 mongrel dogs. The tissue response within and beneath these endoprostheses was studied and compared to that for control Palmaz stents with angiographic and histologic examination at 1, 3, and 6 months.nnnRESULTSnThe bare Palmaz stent endothelialized faster and with a thinner neointima than either covered stent design. Neointima formation proceeds from the ends toward the center of PTFE-covered stents regardless of design, with minimal transgraft tissue penetration. However, the pattern of neointimal response differed for the two designs and suggests that early thrombus formation at the stent-graft interface promotes neointimal development.nnnCONCLUSIONnThe bare Palmaz stent showed the least amount of luminal encroachment at all time points compared with either covered stent. Regarding the covered stents, the different patterns of tissue response with the covered stents may provide insight into the design of stent-grafts for human use.

Evaluation of a New Percutaneous Stainless Steel Greenfield Filter

PURPOSEnTo evaluate a new percutaneous Greenfield filter with an alternating hook design and over-the-wire delivery system.nnnMATERIALS AND METHODSnThe alternating hook stainless steel Greenfield filter was evaluated in a prospective clinical trial between March 10, 1994, and January 27, 1995. Filters were placed in 75 patients in nine clinical centers and follow-up with radiographs and ultrasound scans was carried out at 30 days.nnnRESULTSnClinical trial results revealed successful placement in all patients. There were four cases of filter limb asymmetry (5.3%) without clinical sequelae, with one incidence of failure to span the cava. No significant migration was found. There were no clinically suspected pulmonary emboli, but one instance of probable caval penetration (1.7%) did occur. Caval occlusion was documented in three patients (5%).nnnCONCLUSIONnThe percutaneous stainless steel Greenfield filter provides ease of insertion and improved deployment while maintaining the high standards of efficacy and safety associated with the standard and titanium Greenfield filters.

Delayed onset of ascending paralysis after thoracic aortic stent graft deployment

Delayed spinal cord ischemia after thoracic aortic aneurysm repair is an infrequent but devastating complication. The use of stent grafts to exclude aortic aneurysms is thought to decrease the incidence of the neurologic deficit because there is no period of significant aortic occlusion. We report a case of paraplegia that progressed to quadriplegia occurring 48 hours after the apparently successful deployment of a thoracic aortic stent graft.

Tissue Response to Covered Wallstents

PURPOSEnTo evaluate and compare the healing response related to two types of graft-covered Wallstents (WSs) and an uncovered WS in the canine iliac artery.nnnMATERIALS AND METHODSnEight bare mesh WSs, 10 polyethylene terephthalate interbraided WSs (PET-WSs), and six polytetrafluoroethylene covered WSs (ePTFE-WSs) were placed in the iliac arteries of 12 dogs. Arteriograms were obtained before and after implantation and at explantation. Devices were explanted at 1 month (n = 8), 3 months (n = 6), and 6 months (n = 10) and sent for histologic study.nnnRESULTSnOne ePTFE-covered stent-graft was found to be thrombosed at 3 months; the remaining 23 of 24 implants remained patent to the time of explantation. The WS and ePTFE-WS both generated a uniform myointimal cell response without inflammation. The PET-WS induced a fibrous luminal response with substantial foreign body-type inflammatory reaction around the PET fibers. Although neointima associated with the PET-WS appeared thicker than that associated with either the ePTFE-WS or the bare WS, none of the patent implants developed greater than 50% angiographic narrowing.nnnCONCLUSIONnThe PET-WS induced chronic inflammation, a response not seen with either the WS or ePTFE-WS. This may explain the occurrence of pain and/or fever in human studies of arterial PET endoluminal stent-grafts. Patency for all three implants was excellent in this model.

COMBINATION "SANDWICH THERAPY FOR EXTENSIVE RENAL, CALCULI IN 100 CONSECUTIVE PATIENTS: IMMEDIATE, LONG-TERM AND STRATIFIED RESULTS FROM A 10-YEAR EXPERIENCE

PURPOSEnWe determined the immediate and long-term efficacy of combination sandwich therapy for management of large, extensively branched calculi in 100 consecutively treated patients.nnnMATERIALS AND METHODSnWe treated 61 women and 39 men for stones ranging from 2.2 to 66 cm2 (mean 20.8) with percutaneous debulking followed by shock wave lithotripsy and, when necessary, secondary nephroscopy via the mature tract. The primary debulking was performed via 1 to 3 tracts (total 106, mean 1.06 per patient), following which 1 to 3 shock wave treatments (total 127, mean 1.3 per patient) were administered. Subsequently, 62 patients underwent 71 secondary or tertiary percutaneous procedures (mean 1.1 per patient).nnnRESULTSnTotal hospital stay ranged from 3 to 44 nights (mean 12.2) and decreased with experience. In 34 patients 40 complications developed, the most frequent of which were bleeding requiring transfusion in 14 patients and fever or sepsis delaying a planned procedure or hospital discharge in 20 patients. For patients with struvite stones the transfusion rate and fever/sepsis rate was 20 and 33%, respectively, compared to only 10 and 12%, respectively, for those patients with noninfection related stones. Of 87 patients available for 1-month radiographic followup 55 (63%) were stone-free, while 32 (37%) had discrete residual gravel. With time and experience, the stone-free rate improved from 52 to 70%. Of 55 patients followed for a mean of 40.5 months ipsilateral stones recurred in 13 (22.8%). Of 39 patients with struvite calculi 11 (28%) had recurrent bacteriuria or infection. Renal function, defined by serum creatinine, ranged from 0.6 to 3.9 mg./dl. (mean 1.3) before treatment and from 0.5 to 6.4 mg./dl. (mean 1.4) 1 to 101 months (mean 31) after treatment.nnnCONCLUSIONSnThis combined sandwich approach offers immediate and long-term results comparable to other forms of management currently available for these challenging cases. Furthermore, this approach may be applied successfully to virtually any patient with large, extensively branched or otherwise complex stones.

Directional Atherectomy Treatment for Hemodialysis Access: Early Results☆

The Simpson atherectomy device was used to treat 12 intragraft stenoses, six complete subclavian vein occlusions, and 14 venous outflow stenoses in 24 patients undergoing hemodialysis. Patients were followed up clinically and by means of venography at approximately 1, 3, 6, 9, and 12 months after treatment. Twenty-eight atherectomy specimens were examined histologically. Twenty-six (81%) of 32 lesions were treated with initial technical success. Including technical failures, seven (58%) of 12 intragraft stenoses are angiographically patent at a mean of 5.0 months and five (50%) of 10 are clinically patent at 6 months. Three (50%) of six subclavian veins are angiographically patent at a mean of 5.6 months, and four (67%) of six are clinically patent at 6 months. Three (21%) of 14 venous outflow stenoses are angiographically patent at a mean of 5.0 months and five (38%) of 13 are clinically patent at 6 months. Histologic examination showed neointimal fibromuscular hyperplasia in 26 of 28 lesions. When 30% or less angiographic residual stenosis is used as the criterion for initial technical success, directional atherectomy appears to be effective therapy for intragraft stenoses and, with balloon angioplasty, for some catheter insertion-related subclavian occlusions. Directional atherectomy appears to have a recurrence rate for venous outflow stenoses similar to that for balloon angioplasty when the same criterion is used.