Diagnosis, Management, and Outcome of Aortitis at a Single Center

BACKGROUND

Aortitis is a rare condition with inflammatory or infectious etiology that can be difficult to diagnose due to the highly variable clinical presentation and nonspecific symptoms. However, current literature on the diagnosis, management, and prognosis of aortitis is extremely scarce.

METHODS

We retrospectively reviewed all patients' charts who were diagnosed with giant cell arteritis, Takayasu arteritis, or noninfectious aortitis presenting at a single center between January 1, 2009, and April 17, 2015. Data collected included demographics, medical history, comorbidities, laboratory and imaging data, management, and outcome.

RESULTS

Among the included 15 patients presenting with aortitis at our center, 53% were diagnosed with Takayasu arteritis, 33% with idiopathic inflammatory aortitis, and 13% with giant cell arteritis. All patients received steroid treatment, 67% received adjunctive immunosuppressants or immunomodulators, and 33% underwent interventional procedures. Based on clinical presentation and laboratory and imaging findings at the last follow-up visit for each patient, 67% showed improvement, 27% had no change in disease activity, and 7% had a progression of the disease.

CONCLUSIONS

Takayasu arteritis was found to be more common than idiopathic inflammatory aortitis and giant cell arteritis among our 15 cases diagnosed with aortitis. All patients received medical therapy and 33% received interventional procedures, leading to 67% improvement of disease activity or related complications. This article also offers a comprehensive review of the diagnosis, management, and outcome of aortitis, supplementing the very limited literature on this disease.

Fibrinogen Level as a Surrogate for the Outcome of Thrombolytic Therapy Using Tissue Plasminogen Activator for Acute Lower Extremity Intravascular Thrombosis

Purpose:

Monitoring of fibrinogen level is used to predict bleeding during lower extremity tissue plasminogen activator (tPA) infusions for peripheral arterial or venous thrombolysis. This practice is not fully addressed in the literature.

Materials and Methods:

We retrospectively reviewed fibrinogen levels and studied bleeding rate from charts of patients who underwent lower extremity tPA infusions at a single hospital from January 2010 to May 2012.

Results:

The rate of thrombolytic success did not correlate with fibrinogen level ( P = .53). The rate of major bleeding was significantly higher for patients with a fibrinogen level at or below 150 mg/dL ( P = .01). Patients whose tPA infusion was terminated within 46 hours had significantly lower rates of major bleeding ( P = .01) and thrombolytic failure ( P < .01). Periprocedural systolic blood pressure above 160 mm Hg was a risk factor for major bleeding ( P = .02). There was no association between concomitant aspirin use ( P = .90, .51) or hourly tPA dose ( P = .71, .62) and thrombolytic success or major bleeding, respectively.

Conclusion:

Fibrinogen level ≤150 mg/dL is associated with increased risk of major bleeding during tPA infusions. We suggest serial fibrinogen measurement as a viable method to monitor bleeding risk during lower extremity tPA infusions.

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.

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.

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.

Time course of satisfaction of search

"Satisfaction of search" (SOS) refers to the effect in which a second lesion remains undetected after detection of another lesion on the same radiograph. The objective of this study was to clarify our understanding of SOS by relating it to total time of inspection and time intervals before, between, and after discovery of lesions. Detection accuracy of native lesions in chest radiographs, before and after the addition of a simulated nodular lesion, was measured for ten observers. Analysis of data from this and a previous experiment showed that average perceptual accuracy of individual receiver operating characteristic curves was significantly reduced with the addition of the nodules. Plots and analyses of search time revealed that, on average, during a typical 46-second inspection of a case, simulated nodules were found at 18 seconds, native abnormalities at 25 seconds, and false positives occurred at 33 seconds. Time needed to find nodules did not depend on whether native lesions were present; time to find native lesions did not change with addition of nodules; and total search time was the same for images with one, two, or no lesions. The detection results show that the SOS effect was obtained, but that interrupting search in order to measure it also diminishes accuracy. Analysis of the time course data relates SOS to perceptual capture and strategic halting of search.

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.

Six-month follow-up after thermal balloon angioplasty in canine iliac arteries

We performed thermal balloon angioplasty in 10 iliac arteries in 5 mongrel dogs. By perfusing a modified angioplasty balloon with hot (100 degrees C) saline, a mean balloon temperature of 84 degrees C was obtained. Angiographic and histologic follow-up at 6 months revealed no thrombosis or aneurysm formation but it did reveal fibrotic transformation of the media. Initial overdilatation was maintained in 9 of 10 arteries. We conclude that medial sclerosis induced by thermal balloon angioplasty does not result in aneurysm or thrombosis in dogs.

Nephrotoxicity from contrast material in renal insufficiency: ionic versus nonionic agents

Controversy exists over whether use of low-osmolality contrast agents is of any benefit in mitigating the risk of contrast material-induced nephrotoxicity (CN) in patients with impaired renal function. To test this hypothesis, 101 adult inpatients with high serum creatinine levels (range, 1.4-2.4 mg/dL [120-210 mumol/L]) undergoing contrast material-enhanced computed tomography were randomized to receive ionic or nonionic (low-osmolality) contrast agents in a uniform dose. Changes in serum creatinine level at 48 hours were measured. Seven (14%) of the 50 patients receiving ionic contrast media experienced an increase of 25% or more in serum creatinine level. Only one (2%) of the 51 patients receiving nonionic contrast agents experienced such an increase, a statistically significant difference (P less than .05). In the subset of 25 diabetic patients, the difference was of a similar magnitude. These data suggest that ionic contrast media are more likely than nonionic contrast agents to cause mild exacerbation of renal insufficiency when given intravenously. However, there were no cases of clinically important CN in the study.

Hematoma formation after diagnostic angiography: effect of catheter size

The authors studied the effect of catheter size on the development of hematomas after catheterization. Four hundred ninety-nine patients who underwent routine diagnostic angiography were randomized to receive either 5-F or 7-F catheters. Small hematomas were more frequent in the 7-F catheter group (P less than .05); however, there was no difference in the frequency of larger hematomas between groups. Compression time was slightly but significantly (P less than .001) longer in the 7-F group. When catheter size; duration of the procedure; and patient age, weight, blood pressure and coagulation status were considered as independent variables, patient weight was the most accurate predictor of hematoma formation. The authors conclude that catheter size does not affect the development of a clinically significant hematoma after diagnostic angiography and that other factors such as patient weight are more important in this regard.

Two urokinase dose regimens in native arterial and graft occlusions: initial results of a prospective, randomized clinical trial

The effects of two urokinase (UK) dose regimens on lysis time, lytic success, primary clinical success, and frequency of complications of peripheral thrombolysis were compared. Seventy-two intraarterial UK infusions were performed by means of standard catheter-directed infusion techniques in 63 patients with symptomatic peripheral arterial or bypass graft occlusions. Patients were prospectively randomized to high-dose (250,000 U/h for 4 hours and then 125,000 U/h) or low-dose (50,000 U/h) regimens. The mean time to complete lysis was 20.8, 26.0, 16.5, and 18.2 hours for the high-dose artery, low-dose artery, high-dose graft, and low-dose graft groups, respectively (P was not significant). Respective mean infusion durations were 27.1, 35.4, 22.2, and 25.3 hours. Clinical success was achieved in 65%-85% of cases. The frequency of complications was equivalent between groups, except for a higher frequency of minor bleeding complications in the high-dose group. The two urokinase dose regimens studied were equally effective in enabling peripheral thrombolysis.

Peripheral atherectomy: experimental results with a new device

The size of present rotational atherectomy devices is limited in part by a tendency to produce vessel torsion. The authors designed and investigated a large-bore rotational atherectomy device for peripheral atherectomy in a single pass without significant torsion. A plaque was retrieved from 36 of 40 cadaveric iliac arteries. The mean plaque size was 8.4 x 3.9 mm, and the average number retrieved per artery was two. Thirty of 34 severely calcified arteries were treated successfully. Effluent study revealed no distal embolization; however, six perforations and four dissections occurred. Preliminary results suggest that a cutting surface with a relatively large diameter can be designed to be effective without producing vessel torsion. Changes in future designs will include added flexibility and expandable cutting surfaces to enhance safety and minimize entry diameter.

Thermal balloon angioplasty in a canine model: preliminary results

Preliminary results suggest that thermal balloon angioplasty (BA) may produce plaque welding, decreased elastic recoil, and increased luminal caliber. The authors report results of a simple method of thermal BA in a canine model. Seven mongrel dogs (15-25 kg) underwent conventional BA of each iliac artery with balloons that were 1-2 mm larger than the vessel lumen. The balloons were then perfused with a mixture of saline and contrast material at either 25 degrees C (control) or 100 degrees C for 1 minute. Compared with baseline measurements, thermal BA produced greater lumen enlargement (+16.7%) than control BA (+3.4%) immediately after the procedure (P less than .05). This trend persisted in vessels studied after a delay of 2, 4, or 12 weeks. Histologic sections from specimens studied after a delay demonstrated intimal hyperplasia in both the thermally treated and control arteries. Medial sclerosis was consistently seen in the thermally treated arteries. The authors conclude that thermal BA results in immediate and delayed increases in arterial diameter compared with conventional BA due to decreased elastic recoil and medial sclerosis.

Plaque modification with tetracycline: enhanced tissue ablation with the excimer laser

Tetracycline has been shown to collect selectively in atherosclerotic plaque and is a known photosensitizing agent. To determine if tetracycline enhances the photoablative effects of the ultraviolet xenon-fluorine excimer laser, the authors exposed four cadaveric aortic samples to tetracycline and four to only normal saline. Ninety-three sites in the samples were subjected to laser energy and analyzed with light microscopy for crater depth and width and for degree of thermal injury. Forty-three of the sites were histologically normal, and 50 were atherosclerotic. Crater depth did not differ significantly in atherosclerotic and normal sites not exposed to tetracycline. Atherosclerotic sites exposed to tetracycline showed significantly deeper craters compared with those in normal, exposed sites. The effects of tetracycline exposure and histologic characteristics (normal vs atherosclerotic) on crater width and thermal injury were independent and additive. When the excimer laser is used for treatment, tetracycline can definitely enhance atherosclerotic plaque ablation.

New guide wire for high-flow infusion

A new open-ended guide wire with a large internal diameter was compared with two other open-ended guide-wire and catheter infusion systems. Simple experiments were performed to compare flow rates and ability to track. The larger internal diameter of the new wire allowed higher flow rates and accepted an 0.025-inch (0.64-mm) guide wire. The flexibility of the new infusion wire was shown to be equivalent to that of the catheter system. The authors conclude that the new wire has advantages in terms of flow rates and ability to track, compared with presently available infusion systems.

Techniques for lower-limb angiography: a comparative study

Three separate variables--volume of contrast material, site of contrast material injection, and arterial inflow occlusion--were tested in a prospective, randomized fashion in 52 patients to determine the best technique for lower-limb angiography. Twelve patients received 30 and 60 mL of contrast material injected at the level of the external iliac artery (EIA), 20 patients received 60 mL injected at the level of the EIA with and without inflow occlusion, and 20 patients received 120 mL injected at the level of the aortic bifurcation and 60 mL injected at the level of the EIA. A total of 104 angiograms were obtained, two in each patient. Two examiners reviewed all angiograms in a blinded fashion, initially as 104 separate studies for diagnostic adequacy (ie, the need for additional angiography) and then as 52 paired studies for direct comparison of the quality of arterial filling (ie, the best-appearing angiogram). The 60-mL studies were significantly better (P less than .001) in both categories when compared with both the 30- and the 120-mL studies. There was, however, no significant difference between the 60-mL studies with and without inflow occlusion. The authors conclude that the best screen-film lower-limb angiograms are obtained with large volumes (60 mL) of contrast material injected below the pelvic vessels (EIA).

Vascular applications of laser

The authors review the current experimental and clinical literature relating to the use of lasers in peripheral vascular disease. During the past few years, significant strides have been made in effective harnessing of laser energy for percutaneous revascularization. However, the role of lasers in treating vascular disease is not yet clear. Thus current application of laser technology in this area should be considered experimental until adequate clinical studies confirm its efficacy.

Thrombus-trapping efficiency of the Greenfield filter in vivo

A total of 100 radiopaque blood clots were injected into seven adult sheep under fluoroscopic observation to assess the clot-trapping efficiency of the Greenfield vena caval filter. Eleven percent of the clots passed through the filter, with all failures limited to the two smallest clot sizes: 4 x 10 mm (five of 25) and 4 x 30 mm (six of 25). The Greenfield filter was 100% efficient in trapping larger clots (8 x 10 mm and 8 x 30 mm). There was a tendency toward poorer clot-trapping performance when the Greenfield filter was tilted within the vena cava, but this was not significant. There were no significant differences in hemodynamic measurements obtained immediately before and after injection of each clot, and no significant changes were noted in the animal's hemodynamic status or in blood gas measurements in those cases in which the clots passed through the filter. Since the caval diameter in sheep approximates that in humans, the authors conclude that the Greenfield filter in the clinical setting is capable of stopping large, likely fatal, emboli and a large number of smaller, possibly less clinically significant, emboli.

Incidental fibromuscular dysplasia in potential renal donors: long-term clinical follow-up

The clinical natural history of renal arterial fibromuscular dysplasia (FMD) in patients with normal blood pressure is unknown, to the authors' knowledge. The authors reviewed the results of 1,862 renal angiograms obtained in potential renal donors. FMD was present in 71 patients (3.8%). The average age at which FMD was discovered was 50.8 years. Seventy-five percent of the patients with FMD were female. Of 30 patients who did not undergo nephrectomy, eight (26.6%) developed hypertension over a mean followup interval of 7.5 years. Of 19 patients who underwent nephrectomy, despite the presence of FMD, five (26.3%) developed hypertension over a mean follow-up interval of 4.4 years. In comparison, three subjects (6.1%) (from a randomized control group of 49 age- and sex-matched healthy individuals) developed hypertension over a mean follow-up period of 7.1 years. The authors conclude that asymptomatic middle-aged individuals with renal FMD develop hypertension at a rate greater than that of age-matched control subjects with normal blood pressure.

Thrombosed polytetrafluoroethylene hemodialysis fistulas: salvage with combined thrombectomy and angioplasty

Combined thrombectomy and angioplasty was performed for 19 thrombosed polytetrafluoroethylene grafts. Patency for more than 1 week was achieved in 16 of the 19 grafts (84%). The average duration of graft function after angioplasty in all 19 grafts was 7.1 months (range, 0-32.3 months). Eleven of the 19 grafts (58%) were functioning 5 months after the procedure; seven are still functioning. Combined thrombectomy and angioplasty offers a viable alternative to thrombolytic therapy or complete surgical revision.

Political trends in vascular and interventional radiology: a randomized survey

There is a trend in the United States toward the performance of vascular and interventional radiology procedures by nonradiologists. A survey was conducted of 2.069 U.S. radiologists to define better the current status of and gather opinions on the future of vascular and interventional radiology. A total of 715 (35%) completed questionnaires were returned. Cross tabulations among subgroups of respondents were performed to address key issues. The median proportion of time spent in the performance of vascular and interventional radiology was 10%, and 51.5% of the radiologists surveyed were in groups that included a fellowship-trained interventional radiologist. More than half (54.4%) of the radiologists indicated that nonradiologists have expressed interest in performing vascular and interventional techniques. According to 13.4% of the radiologists surveyed, cardiologists performed at least some peripheral angiography or angioplasty. The vast majority of radiologists (96.8%) did not want other specialties to assume vascular and interventional radiology procedures, but 16.8% believed these procedures will eventually be lost to other specialties. The results indicate that vascular and interventional radiology is being infringed on to a relatively large degree by other specialties.

Urinary obstruction in renal transplants: diagnosis by antegrade pyelography and results of percutaneous treatment

We reviewed our experience with 51 renal transplants to evaluate the accuracy of antegrade pyelography as compared with that of sonography and nuclear renography in the diagnosis of transplant obstruction. Also, the results of percutaneous treatment were analyzed in 44 of these patients. Obstruction was clinically suspected in all of the patients (increased serum creatinine levels and decreased urine output). Antegrade pyelography showed obstruction in 44 (86%) of the 51 patients, and nephrostomy drainage catheters were inserted. Sonography showed pyelocaliectasis in all 49 cases in which it was performed; in 42, the pyelocaliectasis was due to obstruction (14% false-positive rate). Nuclear renography showed obstruction in only six (18%) of 33 cases in which it was performed; all six cases proved to be obstructed (0% false-positive rate and 82% false-negative rate). Twenty-two (50%) of the 44 patients treated with nephrostomy drainage were managed successfully without surgical intervention; seven of these 22 required balloon dilation of ureteric strictures in addition to catheter decompression of the collecting system. The average duration of catheterization required for successful percutaneous treatment was 35 days. This experience suggests that antegrade pyelography has a definite role in the workup of patients suspected of having renal transplant obstruction. The percutaneous access permits successful catheter drainage. Compared with antegrade pyelography, sonography is reasonably accurate in determining the presence of urinary obstruction, although false-positive diagnoses are found in a substantial number of patients. Nuclear renography is not, however, a useful indicator of obstruction owing to its high false-negative rate. Percutaneous treatment of urinary obstruction in transplantation patients proves successful in approximately 50% of cases.

Urine leaks after renal transplantation: value of percutaneous pyelography and drainage for diagnosis and treatment

We reviewed our experience with 12 renal transplant patients who had urine leaks to compare the accuracies of sonography and nuclear renography with that of antegrade pyelography in establishing the diagnosis. The leak was proved by surgery in 11 of the 12 cases. We also determined the role of diverting percutaneous nephrostomy drainage in the treatment of such leaks. The diagnosis was established by sonography in eight (67%) of the 12 patients. Nuclear renography, performed in nine patients, showed decreased renal function but showed the leak in only three (33%) of the nine cases. Antegrade pyelography, performed in all 12 patients, showed leakage in 10 (83%). In the other two patients, follow-up nephrostograms done within 24 hr showed leaks near the ureterovesical anastomotic site. Seven of 11 patients who were managed with a combination of percutaneous nephrostomy drainage and surgical reconstruction were treated successfully (i.e., a functioning graft was retained); however, only one patient was managed successfully by percutaneous methods alone. Antegrade pyelography is more accurate than sonography and nuclear renography in the detection of urine leakage after renal transplantation. However, percutaneous nephrostomy drainage appears useful only as an adjunct to surgery for treatment of this complication.

Spermatic vein embolization with hot contrast material: fertility results

Spermatic venography with hot contrast material embolization was undertaken in 81 patients with varicoceles and infertility. Long-term follow-up information was available in 91% of the patients, and there was an overall conception rate of 40.5%. Embolization with hot contrast material was easily performed without special embolization devices and proved to be a safe and effective technique.

Current trends in the management of urinary stones

The treatment of renal and ureteral stones has undergone rapid and major changes over the past ten years. Extracorporeal shockwave lithotripsy has become the most commonly used modality for the treatment of renal and upper ureteral stones. Lower ureteral stones are more commonly being approached by retrograde techniques. Percutaneous nephrolithotomy, medical therapy, and open surgical nephrolithotomy offer viable alternatives in given situations. Presented here is the current application of each of these techniques, both alone and in combination, for the treatment of urinary stones.

Safe splenoportography

The records of 37 patients who had undergone splenoportography, including one group of 12 who were studied before 1976 and a second group of 25 who were studied after 1977, were reviewed. The primary difference was that in the second group, the tract in the spleen was occluded with absorbable gelatin sponge (Gelfoam) plugs as the needle was withdrawn. In addition, there were minor changes in technique, such as changes in the needle puncture angle and entry site. When the new technique was used, there was a significant decrease in the complications traditionally associated with splenoportography. This procedure is safe and deserves to be considered the procedure of choice in patients in whom precise anatomic information is needed preoperatively that cannot be obtained with noninvasive procedures such as ultrasound or magnetic resonance imaging.

A new vena caval filter for percutaneous placement and retrieval: experimental study

A new vena caval filter that can be inserted percutaneously through an angiographic catheter is described. The filter is secured by controlled penetration of the caval wall and is designed for percutaneous retrieval. The filter was easily and safely placed and removed in 11 mongrel dogs, and in an in vitro study, the filter was shown to be highly effective and less dependent than the Greenfield filter on positioning. The authors believe that the filter will be suitable for prophylactic placement in patients at high risk for pulmonary thromboembolic disease.

Obliteration of the gallbladder without formal cholecystectomy. A feasibility study

Obliteration of the gallbladder without formal cholecystectomy was attempted in 36 rabbits, using an open technique for cannulation of the gallbladder during laparotomy. The gallbladder was cannulated, the proximal cystic duct was occluded with cyanoacrylate-nitrocellulose 2% wt/wt, and the gallbladder mucosa was exposed to various sclerosing agents to induce fibrosis. Heated 60% diatrizoate meglumine and absolute alcohol induced a controllable chronic cholecystitis with transmural fibrosis within two weeks, a result not seen with morrhuate sodium or in the control groups. All animals survived without complications, and no instances of common bile duct damage or occlusion was noted. The results reported are promising and indicate the need for further studies of this technique for its efficacy and safety.