Hydrodynamic thrombectomy system versus pulse-spray thrombolysis for thrombosed hemodialysis grafts: a multicenter prospective randomized comparison

PURPOSE

To evaluate the safety and efficacy of a hydrodynamic thrombectomy system in a prospective, multicenter randomized comparison with pulse-spray thrombolysis in hemodialysis grafts.

MATERIALS AND METHODS

Nine centers enrolled 120 adult patients with recently (</=14 days) thrombosed hemodialysis grafts. Graft venography was used to confirm occlusion in 62 patients randomly assigned to thrombectomy and 58 to thrombolysis. For thrombolysis, a mixture of 5,000 U of heparin and 250,000 U of urokinase was distributed throughout the thrombus, first to the venous then to the arterial graft end. For thrombectomy, the catheter was passed in the same sequence. Technical success was removal of 80% or more of thrombus. Clinical success was technical success plus the ability to dialyze. Also assessed were total procedure time, thrombus treatment time, procedure-related blood loss, other complications, and 30- and 90-day outcomes.

RESULTS

Patient demographics were comparable. Technical success rates were 95% (59 of 62) for thrombectomy and 90% (52 of 58) for thrombolysis (P: =.31). Clinical success rates were 89% (55 of 62) and 81% (47 of 58), respectively (P: =.24). At 30 days, 69% (43 of 62) and 66% (38 of 58), respectively, could be dialyzed through the graft (P: =.70); at 90 days, the rates were 40% (25 of 62) and 41% (24 of 58), respectively (P: =.91). None of these differences or those for procedure-related blood loss and early and late complications were statistically significant. Thrombus treatment times of 16.8 minutes for thrombectomy and 23.4 minutes for thrombolysis were significantly different (P: <.01).

CONCLUSION

The hydrodynamic thrombectomy system is at least as efficacious and safe as pulse-spray thrombolysis but shortens thrombus treatment time.

Thrombolytic therapy with use of alteplase (rt-PA) in peripheral arterial occlusive disease: review of the clinical literature. The Advisory Panel

PURPOSE

The clinical literature describing the use of alteplase in the treatment of peripheral arterial occlusive (PAO) disease is reviewed.

MATERIALS AND METHODS

The literature database was acquired by a MEDLINE search using the Boolean keyword string: tissue plasminogen activator and/or rt-PA and peripheral not animal. A review was performed to identify the dose range of alteplase, technique of infusion, use of anticoagulation, clinical success rates, and risk of complications.

RESULTS

Forty-six clinical studies were identified. There are few prospective, randomized clinical trials and a lack of standardized protocols and endpoints. Use of catheter-directed infusions of recombinant tissue plasminogen activator (rt-PA) may be beneficial versus surgery in the initial management of acute limb ischemia (< 14 days) and in reducing the magnitude of subsequent surgical or percutaneous revascularization. For patients with chronic limb ischemia (> 14 days), irreversible acute limb ischemia, or advanced diabetic arteriopathy, catheter-directed infusion of rt-PA or other plasminogen activators may be unsuitable. The risk of adverse bleeding appears related to the overall dose and duration of infusion. These risks appear similar to those of urokinase. The role of heparin in increasing adverse bleeding during rt-PA therapy is unclear.

CONCLUSIONS

There is no generally accepted dose or technique for administering catheter-directed thrombolysis using alteplase; however, several studies have demonstrated its clinical safety and efficacy. Formal studies will be required to determine the optimal dose, technique of infusion, the role of anticoagulation, and complication rates when alteplase is used for PAO disease.

Balloon angioplasty or stent placement in patients with azotemic renovascular disease: a retrospective comparison of clinical outcomes

In this study comparing functional outcomes of renal angioplasty alone (PTRA) or angioplasty with stent placement in patients with renal artery stenosis (> or =60%) and renal insufficiency, 69 patients were treated with PTRA or stent placement. After censoring, the PTRA group included 15 patients with a mean age of 75 years, mean serum creatinine (Cr) of 2.9 +/- 1.4 mg/dL, and mean follow-up of 10 months. The stent placement group included 40 patients with a mean age of 71 years, mean Cr of 2.6 +/- 1.2 mg/dL, and mean follow-up of 12 months. Stenting was performed primarily in four cases and after suboptimal angioplasty in the remainder. Benefit was defined as either stabilization (+/-20%) or improvement in serum Cr levels. Technical success was achieved in 16 of 17 (94%) PTRA patients and 55 of 58 (95%) patients receiving stents. Complications included one surgically repaired axillary pseudoaneurysm, one distal stent positioning requiring a second stent, one stent protruding 5 mm into the aorta, two dissections requiring additional stents, one retroperitoneal hematoma, and one intrarenal atheroembolism treated with thrombolysis. Three patients (mean initial Cr 3.9 mg/dL) required hemodialysis within 30 days of stenting. One patient discontinued dialysis after stenting. There were two procedure-related deaths. An overall benefit was seen in 40% of patients after PTRA and 66% of patients after stent placement. For the stent placement and PTRA groups, cumulative clinical benefit was 77% and 80%, respectively, at 3 months; 69% and 64%, respectively, at 6 months; 61% and 41%, respectively, at 12 months; and 48% and 14%, respectively, at 24 months. A 50% loss of cumulative benefit was seen 34 months after stenting and 11.5 months after PTRA. In the stent and PTRA groups, benefit was noted in 77% and 57%, respectively, of patients with an initial Cr of 2.3 or less, 53% and 25%, respectively, of patients with an initial Cr level higher than 2.3, and 44% and 17%, respectively, of patients with an initial Cr level of 3.0 mg/dL or more. For patients with renal insufficiency, renal artery stenting provides superior clinical results compared with PTRA, mostly because late deterioration occurs after PTRA. Outcomes are related to pretreatment serum Cr level.

Transjugular intrahepatic portosystemic shunt (TIPS) for Budd-Chiari syndrome or portal vein thrombosis: review of indications and problems

OBJECTIVE

The aim of this study was to evaluate the role of transjugular intrahepatic portosystemic shunt (TIPS) in patients who present with portal vein thrombosis (PVT) or Budd-Chiari Syndrome (BCS).

METHODS

Nine patients with recent PVT and four patients with BCS underwent TIPS. The diagnosis was confirmed by color Doppler ultrasound and by angiogram in most patients. Patients were followed clinically and had TIPS checked periodically for patency. The end point was mortality, subsequent surgical shunting or orthotopic liver transplantation (OLT).

RESULTS

TIPS was placed in 13 of 15 (87%) patients with BCS or PVT. The mean decrease in pressure gradient was 56%. Median and mean follow-up were 14 months and 16.9 months. Procedure related complications occurred in two of 13 (15%), both in the PVT group. Direct procedural mortality was one of 13 (8%). The majority of patients with PVT (five of eight) underwent OLT. Of the remaining three, one patient subsequently developed a cavernous transformation of portal vein but is stable, one patient is stable, without further variceal bleeding, and one patient died because of multiple organ failure. In patients with BCS, three of four (75%) did well with TIPS, but one patient required immediate surgical shunting after occlusion of the TIPS. Two patients underwent OLT and the fourth patient is stable 2 yr later but has cirrhosis on biopsy.

CONCLUSIONS

In patients with BCS, TIPS placement is effective and can be used as a bridge to liver transplantation. TIPS in the noncavernous PVT group should only be recommended when cirrhosis and uncontrollable variceal bleeding are present.

Placement of a PTFE-covered Wallstent through a 12 Fr sheath for the exclusion of a common iliac artery aneurysm

We describe a technique for transfemoral endovascular exclusion of an iliac artery aneurysm with a reconstrained polytetrafluoroethylene (PTFE)-covered Wallstent inserted through a 12 Fr sheath after right femoral artery cutdown. The procedure was successfully performed, with evidence of complete aneurysm exclusion at 4-month follow-up. This technique reduces the caliber of the introducer needed to deploy the covered Wallstent. It should be noted that because of a leak, an additional covered Palmaz stent was also deployed.

Feasibility of using a swine portal vein containing a metallic stent for creating a portacaval shunt

RATIONALE AND OBJECTIVES

We evaluated the feasibility of using a metallic stented portal vein as a conduit for portacaval shunt in pigs.

METHODS

A metallic self-expanding stent was placed in the portal vein of five pigs under combined ultrasound and fluoroscopic guidance via a percutaneous transhepatic approach. After 6 weeks, a portacaval shunt was performed using the stented portal vein as a conduit. A single angiogram followed immediately by sacrifice and histologic examination was performed on each pig at a varying time interval postshunt.

RESULTS

One pig died 3 days after the shunt procedure because of a presumed surgical technical failure and a consequent thrombosed portal vein. Angiographic patency of the portacaval shunt was confirmed in the four remaining pigs. Postmortem histologic evaluation showed more complete endothelialization and subintimal organization in the more chronic stents. Thrombus occurred only in the stent of the pig that died. There was no significant luminal obstruction in the other four stents.

CONCLUSION

Our results suggest that a stented portal vein can be used successfully as a conduit for portacaval shunt in pigs.

Percutaneous interventions in adults receiving pediatric "en bloc" double renal grafts

PURPOSE

To present technical adaptations of percutaneous interventional techniques required for the small size vessels and ureters of "en bloc" transplanted pediatric kidneys.

METHODS

Over a 4-year period, 12 adult patients received en bloc pediatric double renal transplants. Small system percutaneous interventional techniques were used in seven patients to approach the infantile renal arteries and urinary collecting systems for 11 percutaneous transluminal renal angioplasties, 4 antegrade pyelograms, and 3 nephrostomies.

RESULTS

Prior to intervention, these patients averaged a creatinine of 2.5 mg%, which decreased to 1.4 mg% at 46 months (range, 22-68) following the first intervention. With a mean follow-up of 42 months (range, 5-47), 9 of 12 (75%) transplants are functioning with an average serum creatinine of 1.3 mg%.

CONCLUSION

With the assistance of percutaneous management of postoperative arterial and ureteral lesions, the prognosis of en bloc renal grafts can approach that of the standard adult renal allograft.

Transjugular intrahepatic portosystemic shunt in nonliver transplant candidates: is it indicated?

BACKGROUND

Transjugular intrahepatic portosystemic shunt (TIPS) is an effective treatment of severe portal hypertension complications. Liver transplantation (LT) candidacy has not been a prerequisite to TIPS placement in some medical centers.

OBJECTIVES

To investigate the outcome and survival of non-LT candidates after TIPS.

METHODS

From November 1991 to February 1994, all patients referred for TIPS placement were evaluated for LT candidacy. Exclusions for LT included: age (> 70 yr), other significant medical conditions, or noncompliance. Indications for TIPS included refractory variceal bleeding during an acute bleed, recurrent bleeding after more than or equal to four sessions of sclerotherapy, or refractory ascites.

RESULTS

Sixty patients received TIPS. Nineteen were considered non-LT candidates. Over a 2-yr follow-up, 14 of these non-LT candidates did not survive. Their median age was 63.5 compared with 56.5 yr for LT candidate nonsurvivors (p < 0.05). Among the 14 non-LT candidate nonsurvivors, 10 were Childs C class, and eight had emergent TIPS placement. The 2-year mortality rate was 84% for non-LT candidates versus 24% for LT candidates. Median survival time for non-LT candidates was 2.6 months compared with 20 months in the LT candidates (p < 0.001). Only one death was due to a TIPS-related complication.

CONCLUSIONS

TIPS is unquestionably an advancement in the management of patients with portal hypertension complications. Non-LT candidates, compared with LT candidates, tended to be older and of a Child-Pugh C class, and they had survival rates often less than 90 days post-TIPS. Given these high mortality rates, we need to address whether TIPS is indicated in these non-LT candidates.

Percutaneous transluminal angioplasty for transplant renal artery stenosis

A recent report has challenged the efficacy and safety of percutaneous transluminal angioplasty (PTA) for the treatment of transplant renal artery stenosis (TRAS). From January 1983 to December 1990, 24 PTA procedures were performed for TRAS in 18 patients. The stenoses were anastomotic in two cases, in the main renal artery in 14, and segmental in eight. After PTA, the residual stenosis was less than 20% in 14 (58%), 20%-50% in four (17%), and greater than 50% in six (25%). The mean diastolic blood pressure decreased from 106 mm Hg 1 day prior to PTA to 82 mm Hg 1 day after PTA. Long-term follow-up mean diastolic blood pressure (at 2-32 months) was 93 mm Hg (P less than .01). Eleven of the 18 patients (63%) had a 10% or greater reduction in diastolic blood pressure on long-term follow-up. Major complications occurred in two patients; one groin hematoma required surgical evacuation, and one polar infarct led to hypertension that was difficult to control. No surgical revisions of the transplant renal artery were necessary. The authors' data indicate that PTA should remain the treatment of choice for nonanastomotic TRAS.

Biliary strictures in hepatic transplantation

Between August 1985 and December 1990, 198 liver transplantations were performed. Among 18 patients, 20 biliary strictures were identified, which were categorized as anastomotic (n = 6), nonanastomotic central hilar (n = 8), and nonanastomotic peripheral (n = 6). Pretransplant disease, hepatic artery patency, presence of acute or chronic rejection, and donor cold ischemia times were tabulated for each case. Among the six patients with peripheral strictures, three had sclerosing cholangitis prior to transplantation. Three patients with nonanastomotic strictures experienced chronic rejection. The mean cold ischemia time for patients with nonanastomotic strictures was 9.75 hours versus 8.1 hours for nonstrictured transplants (P = .025). Balloon dilation was performed in 13 patients; follow-up longer than 6 months was available for nine patients. Dilation was successful in four cases. Among the five failures, only one patient has needed surgery. An association was noted between nonanastomotic biliary strictures and prolonged donor cold ischemia time, between peripheral nonanastomotic strictures and pretransplant sclerosing cholangitis, and between nonanastomotic strictures and chronic rejection. Percutaneous balloon dilation was found useful in the treatment of the strictured transplant.

Ultrarapid urokinase in hemodialysis access occlusion

Over a 3-month period, 14 consecutive hemodialysis access occlusions were treated with 1-1.25 million IU of urokinase (UK) delivered at a rate of 20,000 IU/min. After systemic heparin administration, lytic infusion via the crossed-catheter technique was performed with use of pediatric microdrip pumps, with determination of success within 1 hour. Patency was established radiographically in 11 of 14 occlusions, for a 79% immediate success rate. At 285-day mean follow-up, 9% (one of 11) remained patent without further radiologic or surgical intervention; graft survival was 64% (seven of 11). No significant complications occurred with use of ultrarapid UK. The 1-hour outpatient procedure safely allowed for rapid triage between surgical and radiologic intervention, minimal catheter manipulation or physician dependency, shorter duration compression of any bleeding venipuncture sites during UK administration, and greater patient comfort because of shortened procedure times.

Embolization of a giant renal arterial aneurysm

A 49-year-old man presented with right flank pain. Angiography revealed a giant right renal arterial aneurysm. Giant renal arterial aneurysms are typically treated by nephrectomy. In this patient the aneurysm was embolized successfully with multiple Gianturco-Wallace coils and polyvinyl alcohol. This case indicates that embolization may be a reasonable alternative to nephrectomy.

The pump maneuver: an atraumatic adjunct to enhance US needle tip localization

Real-time ultrasound (US)-guided biopsies and drainage procedures require constant visualization of the needle tip. Ensuring optimum needle tip visualization is paramount to the success of these procedures. The authors have found that pumping the stylet in and out of a stationary needle shaft increases the echo-genicity of the needle shaft and tip, thereby facilitating needle localization. This technique, which we have termed "the pump maneuver," is a quick, useful, and atraumatic adjunct to be considered during US-guided percutaneous needle biopsy and drainage procedures.

Gastric pneumatosis: sign of biliary stent-related perforation

Gastric pneumatosis developed 4 months after a Carey-Coons biliary endoprosthesis was placed in an 85-year-old woman with pancreatic carcinoma. Radiographs revealed a change in the position of the stent. This combination of findings suggested that more than simple stent migration had occurred. At endoscopy, duodenal perforation was confirmed and the stent repositioned. Subsequently, the pneumatosis resolved.

Percutaneous treatment of urine leaks in renal transplantation patients

The data on post-renal transplantation urine leaks in 23 patients were retrospectively reviewed to assess the role of percutaneous urine-diverting procedures in their treatment. The leaks were confirmed by means of antegrade pyelography, and either a nephrostomy catheter or a nephroureteral stent was placed. Nephrostography was performed frequently to evaluate leak closure. Urinary diversion was continued for an average of 68 days. Leak closure was documented in 20 of 23 (87%) cases. In four patients, concomitant infection or multiorgan failure precluded adequate therapy. One patient developed a ureteral stricture after the urine-diverting procedure and required surgical correction. The results suggest that percutaneous urine-diverting procedures are a definitive treatment for post-renal transplantation urine leaks.

US guidance of interventional procedures

Advances in ultrasound (US) machine and transducer design have improved the ability of US to guide interventional procedures. Though affording excellent guidance without radiation and at relatively low cost, US remains underutilized because of lack of understanding and experience in this technique. This article illustrates the role that US has in interventional radiology and explains how to place a needle in a target under US guidance.

Magnetic resonance imaging of adrenal cortical carcinoma

Five cases of adrenal cortical carcinoma examined with magnetic resonance (MR) are presented. Clinical histories, computed tomographic (CT) scans, and final pathologic findings were reviewed in each case. All masses were hypointense compared to the liver on T1-weighted images and became hyperintense compared to the liver on T2-weighted images. Signal intensity of adrenal masses, fat, and liver were measured. Adrenal/liver and adrenal/fat signal intensity ratios were then calculated. All the masses were readily identified with MR. The MR also demonstrated displacement or invasion of adjacent organs, as well as liver metastases. The inferior vena cava was also identified in each case. Even though there were no consistent MR findings to diagnose adrenal cortical carcinomas accurately, superior blood vessel identification and multiplanar capabilities may make MR the imaging modality of choice in evaluating the extent of disease and in planning surgical excision.

Imaging of abdominal aortic aneurysms

There is no single correct approach to evaluate aortic aneurysm. Variations in individual cases, equipment availability, technical expertise, and surgeons' preference frequently dictate the workup. Sonography is optimal for screening and follow-up in uncomplicated cases. CT is excellent in preoperative and postoperative evaluation of aneurysms and their potential complications. Angiography is used to determine visceral-branch involvement and define variations in vascular anatomy, although its routine preoperative use is controversial. MR imaging has emerged as a powerful tool to visualize and stage aneurysms.

Quadrilateral space syndrome: a rare cause of shoulder pain

The authors report a case of quadrilateral space syndrome in a baseball pitcher. The diagnosis was made by means of subclavian arteriography performed with the arm in abduction and external rotation. This entity is a rare cause of shoulder pain caused by occlusion of the posterior humeral circumflex artery in the quadrilateral space.

Cranial ultrasonography and the prediction of cerebral palsy in infants weighing less than or equal to 1200 grams at birth

The rôle of serial cranial ultrasonography in the prediction of cerebral palsy was examined in 116 surviving infants with birthweights less than or equal to 1200 g. All underwent serial real-time sonographic examinations of the brain on days one, five and 21, then monthly, until term corrected age. Intraventricular hemorrhage (IVH) was diagnosed in 48 infants, and three had periventricular leukomalacia. Of the 116 infants, 31 had ultrasound abnormalities at term. At 12 to 18 months corrected age 12 infants had cerebral palsy and 38 were classified as suspect; the other 66 were normal. There was a clear association between risk group, based on sonographic findings at term, and outcome. Infants with IVH whose cranial ultrasounds failed to become normal by term corrected age were at higher risk for cerebral palsy than those with normal examinations at term, regardless of the severity of IVH. Thus an abnormal ultrasound at term corrected age was highly predictive of cerebral palsy, especially among survivors of IVH. It remained the best predictor of cerebral palsy, even when other perinatal and neonatal variables were considered. In contrast, duration of mechanical ventilation, rather than sonographic findings, was the best predictor of suspect neuromotor status.

Prolonged mechanical ventilation and intracranial hemorrhage: impact on developmental progress through 18 months in infants weighing 1,200 grams or less at birth

In this prospective, longitudinal study, the relative impact of intracranial hemorrhage and prolonged mechanical ventilation on developmental progress during the first 18 months of life of infants weighing 1,200 g or less at birth was examined. A total of 159 surviving infants were divided into two groups: infants with and those without intracranial hemorrhage. These groups were then subdivided into groups of infants receiving prolonged mechanical ventilation (greater than 21 days) and those mechanically ventilated for 21 days or less, thus creating four subgroups. Group 1 (intracranial hemorrhage and prolonged mechanical ventilation) and group 3 (intracranial hemorrhage and no prolonged mechanical ventilation) showed no statistically significant differences for severity of intracranial hemorrhage, persistence of ventriculomegaly, or presence of periventricular leukomalacia. A repeated-measures analysis of variance demonstrated a main effect for prolonged mechanical ventilation on outcome as measured by the Bayley Mental Development Index and Bayley Psychomotor Development Index at 4, 8, 12, and 18 months of age (corrected for prematurity). Forward stepwise regression revealed prolonged mechanical ventilation to the best predictor of Bayley indexes at all ages except 4 months of age, for which the Psychomotor Development Index was best predicted by length of hospitalization. No main effect for intracranial hemorrhage was demonstrated, but the motor performance of infants with intracranial hemorrhage declined significantly with age. By contrast prolonged mechanical ventilation was associated with uniformly poor performance at every age and serves as a powerful marker for poor developmental progress during the first 18 months of life in infants weighing 1,200 g or less at birth.

Mycotic right coronary artery aneurysm: CT and MR diagnosis

A clostridial mycotic aneurysm of the right coronary artery was diagnosed by the use of multiple imaging modalities including gated magnetic resonance imaging. Percutaneous drainage was performed as a palliative measure in hope of avoiding repeat sternotomy.

Cavitary periventricular leukomalacia: incidence and short-term outcome in infants weighing less than or equal to 1200 grams at birth

One hundred surviving infants with birthweights less than or equal to 1200 g were examined longitudinally, using real-time ultrasonography of the brain. Five infants were diagnosed as having cavitary periventricular leukomalacia (PVL). One infant expired within a month following discharge; the remaining four entered a follow-up program and received developmental assessments. Three infants had moderate-severe spastic diplegia and the fourth had spastic quadriplegia. Cavitary PVL can be diagnosed in vivo and predicts future motor delay or cerebral palsy. Since the typical site of PVL involves the optic radiations, and the incidence of visual-perceptual disturbances is high in premature infants, further research is needed to explore the possible relationship between these two abnormalities.

Congenital hepatic artery aneurysm simulating pancreatic carcinoma

The authors report a case of a hepatic artery aneurysm that simulated a mass in the head of the pancreas. The correct diagnosis was made preoperatively based on several findings: curvilinear calcification within the mass on CT, a well-defined cystic collection on ultrasound, absence of biliary duct dilatation or jaundice, and presence of other aneurysms.

Dynamic CT in the evaluation of physiologic status of renal transplants

Dynamic computed tomographic scans were performed in 23 patients to evaluate perfusion and function of renal transplants. Using corticomedullary junction and corticoarterial junction attenuation/time curve analysis, we were able to differentiate normal renal transplants from those undergoing rejection. Corticomedullary junction time was used to assess function and was significant in distinguishing normal renal transplants from those with rejection (p less than 0.001). Similarly, corticoarterial junction time was used to assess perfusion and had a significance of p less than 0.05. The study demonstrates the ability of computed tomography to yield excellent physiologic information.