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Biomedical subjects

K Valji

Publications and source records attributed to K Valji.

At least 19 recordsLinked to original sources

Integral role of interventional radiology in the development of a pediatric liver transplantation program.

The aim of this study was to examine the role of interventional radiology (IR) in the pretransplant evaluation of potential living-related liver transplantation (LRLT) donors and in the post-transplant management of pediatric liver transplant recipients. Medical records and procedural reports were reviewed of 12 potential donors and five recipients for left lateral segment liver transplants. Procedures performed by the IR Division, clinical indications, and complications were tabulated. Retrospective calculation of radiation exposure to the skin and gonads of the donors and recipients were made. Three-dimensional ultrasound (3D US) was used in all 12 potential donors to screen for the donor with the most appropriately sized left lateral segment. The four optimal donor candidates underwent contrast angiography in order to measure the diameter and screen for variant arterial supply to the left lateral segment. Pretransplantation, one recipient underwent mesenteric angiography with indirect portography to confirm thrombosis of the portal vein and to prove patency of the splenomesenteric venous confluence. Three children underwent LRLT and two children received split livers from cadaveric donors. Thirty-two IR procedures were performed after transplantation (Tx) in the four transplant survivors (one child died following Tx). These IR procedures included: ultrasound-guided percutaneous liver biopsy to evaluate the pathologic cause of liver dysfunction (seven); placement of nasal jejunal feeding tubes (three) or a peripherally inserted central catheter (four) for nutritional and pharmacologic support; large-volume diagnostic and therapeutic paracentesis (two) and thoracentesis (one); percutaneous catheter drainage of symptomatic large pleural effusions (two), large-volume chylous ascites (one) (with later drain removal [one]), and a large biloma (one); percutaneous biliary drain placement (three), biliary drain replacement (two), and balloon cholangioplasty (four) to relieve obstructive jaundice from biliary enteric anatomic strictures; and mesenteric arteriography (one) for suspected thrombosis of the hepatic artery. No complications occurred. Mean skin and gonadal radiation doses were 193 mGy and 27 mGy, respectively, for donors, and 164 mGy and 60 mGy, respectively, for recipients. Even in a program such as this, with a limited series of pediatric liver Txs, it is apparent that IR plays an integral role in optimizing the clinical outcome and use of resources. Specific benefits included: selection of optimal donors; accurate mapping of the donor and occasionally recipient hepatic vasculature; and, most importantly, providing relatively safe minimally invasive procedures for nutritional support and diagnosis and management of untoward events after Tx. When possible, ultrasound guidance should be used to avoid excessive cumulative fluoroscopic exposure to recipients.

Adolescent↗

Pulmonary embolism from pulse-spray pharmacomechanical thrombolysis of clotted hemodialysis grafts: urokinase versus heparinized saline.

PURPOSE: To compare the frequency and extent of pulmonary embolism (PE) occurring during pulse-spray pharmacomechanical thrombolysis (PSPMT) of clotted hemodialysis grafts with use of either urokinase (UK) or heparinized saline (HS). Postintervention primary patency and complication rates were compared for each method of thrombolysis. METHODS AND MATERIALS: Twenty-seven patients were enrolled in this prospective, randomized, double-blind study evaluating PE with two PSPMT agents. The doses of heparin were similar between groups. The only variable was that one group of patients received UK and the other received HS. In two cases, the venous anastomosis could not be crossed. Eleven patients were treated with UK and 14 with HS. Nuclear medicine perfusion lung scans were performed before treatment and after graft declotting procedures. Lung perfusion was quantified to 10% of a pulmonary segment (0 = normal perfusion, 1 = segmental perfusion defect), with nine segments counted for each lung. RESULTS: Baseline nuclear medicine perfusion lung scan results were abnormal (> or = 20% segmental perfusion defect) in 19 patients (70.4%). New PE (one or more pulmonary segments) occurred in two patients treated with UK (18.2%) and nine patients treated with HS (64.3%; P = .04). All cases of PE were asymptomatic. Quantitative global pulmonary perfusion analyses revealed that treatment with UK improved flow to 0.2 +/- 2.0 pulmonary segments, whereas treatment with HS decreased perfusion to 1.0 +/- 1.7 segments (P = .16, NS). Although postintervention primary patency rates were similar according to life-table analysis (P = .76, NS), complication rates were higher with use of HS (n = 4, 28.6%) than with use of UK (n = 2, 18.2%) (P = .6, NS). CONCLUSIONS: All PE were asymptomatic during PSPMT, but treatment with UK reduced the rate of PE and tended to result in smaller defects in lung scan results. Most patients undergoing hemodialysis have abnormal baseline perfusion scan results, but PSPMT with UK improved many of them. The postintervention primary patency rates were similar between groups, but complications were more frequent after treatment with HS.

Adult↗

Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures.

PURPOSE: To evaluate the usefulness of information provided by three-dimensional ultrasound (3D US) and to determine whether 3D US decreased the number of passes required to obtain portal vein (PV) access during creation of transjugular intrahepatic portosystemic shunts (TIPS). MATERIALS AND METHODS: Intermittent 3D US volume acquisitions were obtained during creation of TIPS in 20 patients. Useful information provided by 3D US was tabulated. The number of passes required to achieve PV access was recorded and results were compared retrospectively to 25 patients who underwent TIPS without 3D US. RESULTS: 3D US documented that the operator's opinion of which hepatic vein had been selected was incorrect in nine patients (45%), detected unfavorable PV anatomy that required modification of equipment or technique in seven patients (35%), permitted estimation of the trajectory required to access the targeted PV in all patients (100%), assisted in selecting the optimal point along the hepatic vein for origination of the needle pass in 11 patients (55%), allowed avoidance of a large hepatocellular carcinoma in one patient (5%), and confirmed that access into the main PV was intrahepatic in four patients (20%). The mean number of needle passes decreased from 10.4 in the historic control group to 4.6 in the 3D US group (P = .0001). CONCLUSION: 3D US provided imaging information that detected technical errors and altered anatomy, and provided positional and directional information to significantly improve needle pass efficiency.

Adult↗

Adjunctive 3D US for achieving portal vein access during transjugular intrahepatic portosystemic shunt procedures.

PURPOSE: To evaluate the usefulness of information provided by three-dimensional ultrasound (3D US) and to determine whether 3D US decreased the number of passes required to obtain portal vein (PV) access during creation of transjugular intrahepatic portosystemic shunts (TIPS). MATERIALS AND METHODS: Intermittent 3D US volume acquisitions were obtained during creation of TIPS in 20 patients. Useful information provided by 3D US was tabulated. The number of passes required to achieve PV access was recorded and results were compared retrospectively to 25 patients who underwent TIPS without 3D US. RESULTS: 3D US documented that the operator's opinion of which hepatic vein had been selected was incorrect in nine patients (45%), detected unfavorable PV anatomy that required modification of equipment or technique in seven patients (35%), permitted estimation of the trajectory required to access the targeted PV in all patients (100%), assisted in selecting the optimal point along the hepatic vein for origination of the needle pass in 11 patients (55%), allowed avoidance of a large hepatocellular carcinoma in one patient (5%), and confirmed that access into the main PV was intrahepatic in four patients (20%). The mean number of needle passes decreased from 10.4 in the historic control group to 4.6 in the 3D US group (P = .0001). CONCLUSION: 3D US provided imaging information that detected technical errors and altered anatomy, and provided positional and directional information to significantly improve needle pass efficiency.

Adult↗

Early rethrombosis of clotted hemodialysis grafts: graft salvage achieved with an aggressive approach.

OBJECTIVE: The purpose of this study was to assess the efficacy of repeated pulsed spray pharmacomechanical thrombolysis for salvage of early rethrombosis of hemodialysis grafts and to identify factors that predict successful outcome. MATERIALS AND METHODS: Thirty-four patients with initial successful thrombolysis were referred for repeated thrombolysis because of early rethrombosis. Repeated thrombolysis occurred within 1 month of initial thrombolysis. Technical success and patency rates were calculated. Causes of graft thrombosis and procedural modifications were analyzed. RESULTS: The 39 rethrombosed grafts were successfully treated using pharmacomechanical thrombolysis, and patients underwent subsequent hemodialysis. The underlying flow-limiting stenoses were treated with balloon angioplasty using a larger balloon (41%), a same-size angioplasty balloon (18%), stent placement (15%), or increased anticoagulation (5%). A new stenosis location was discovered in 18%. Mean primary patency was 80.9 days (2.6 months) and secondary patency was 235.4 days (7.8 months). With life table analysis, 1-, 3-, 6-, and 12-month primary patency rates were 72%, 31%, 23%, and 15%, and secondary patency rates were 77%, 62%, 51%, and 31%, respectively. Graft patency rates in our study were compared with our institutional historic graft patency rates, with no significant difference noted (p = 0.76). No major procedural complications occurred. CONCLUSION: Adequate technical success and patency rates for pharmacomechanical thrombolysis occur even for hemodialysis grafts that rethrombose within 1 month. After thrombolysis, aggressive search for and treatment of additional stenoses are warranted.

Blood Vessel Prosthesis↗

Detection and treatment of dysfunctional hemodialysis access grafts: effect of a surveillance program on graft patency and the incidence of thrombosis.

PURPOSE: To determine the value of a hemodialysis graft surveillance program in reducing the incidence of graft thrombosis and prolonging graft patency by means of early detection and percutaneous transluminal angioplasty (PTA) of graft-related stenoses. MATERIALS AND METHODS: For 4-1/2 years, routine graft examination and measurement of several dialysis parameters were used to identify 106 cases of suspected graft dysfunction in 57 patients (56 men, one woman; aged 27-76 years). Graft-related stenoses detected with angiography were treated with PTA. RESULTS: Abnormal physical examination findings were the most common sole indication of graft dysfunction. Of the 106 cases referred for angiographic evaluation, 97 (92%) had at least one lesion. PTA was successful in 88 of 90 treated cases. The primary patency rates at 1 year were 16% for arteriovenous fistulas (AVFs) and 23% for polytetrafluoroethylene (PTFE) grafts. Early detection of stenoses by means of surveillance and repeated PTA enabled 1-year primary assisted patency rates of 67% for AVFs and 68% for PTFE grafts. The incidence of graft thrombosis fell from 48% in 1988 to 17% in 1994 (P < .001). CONCLUSION: The hemodialysis graft surveillance program resulted in a statistically significant reduction in the incidence of graft thrombosis. Although primary patency rates after PTA were low, repeated PTA of detected stenoses allowed good primary assisted patency rates.

Adult↗

Prolonging the life of difficult hemodialysis access using thrombolysis, angiography, and angioplasty.

Prolonging the life of vascular access sites is one of the most pressing problems facing the nephrology team in the ongoing care of chronic hemodialysis patients. Thus, the ability to salvage a failing vascular access is important in any circumstance, but salvage is particularly critical in medically complicated situations. The following case presents just such a situation, one in which available access sites were limited and in which salvaging the function of a local access site obviated the need for major surgical intervention for more than 4 years. This example shows the efficacy of nonsurgical thrombolysis and the place of vascular radiology in the long-term preservation of access patency and follow-up care.

Aged↗

Postangiographic femoral artery pseudoaneurysms: further experience with US-guided compression repair.

PURPOSE: To assess the efficacy of ultrasound-guided compression repair (UGCR) in postcatheterization femoral artery pseudoaneurysms. MATERIALS AND METHODS: One hundred thirty-three patients with pseudoaneurysms were considered for UGCR. Patients underwent compression with duplex and color Doppler ultrasound. Immediate and long-term successes were evaluated. RESULTS: Seven patients were not candidates for UGCR. UGCR was technically possible in 117 of the 126 patients who were candidates. UGCR was successful in 109 patients. The failure rate was significantly higher in patients who were receiving anticoagulant medication (P < .001). Pseudoaneurysm size, age, and structure (simple vs multiloculated) had no bearing on success or failure. The time required for successful compression was not related to treatment with anticoagulants but was related to pseudoaneurysm structure. Complications included one case of a distal embolus and two episodes of hypotension. CONCLUSION: UGCR is a simple and expedient method for the treatment of postcatheterization femoral artery pseudoaneurysms.

Aneurysm, False↗

Hand ischemia in patients with hemodialysis access grafts: angiographic diagnosis and treatment.

PURPOSE: To determine the cause of symptoms and efficacy of transcatheter therapy in a series of patients with dialysis grafts and hand pain referred for arteriography. MATERIALS AND METHODS: Thirteen patients with 14 hemodialysis grafts underwent arteriography for possible hand ischemia. The sites of proximal graft anastomosis were the distal radial artery (n = 6) and the mid- to distal brachial artery (n = 6). Transcatheter therapy was performed via the graft or by antegrade brachical puncture. RESULTS: The cause of symptoms was ischemia from obstructive arterial disease in seven cases (three with superimposed steal), graft steal alone in three, ischemic monomelic neuropathy in two, and carpal tunnel syndrome in two. Five arterial stenoses were treated with angioplasty, with improvement or resolution of symptoms in four patients. CONCLUSION: In this group, symptoms were usually the result of inflow or outflow arterial disease, alone or in combination with graft steal. Transcatheter therapy (angioplasty or embolization) is effective in selected cases.

Adult↗

Transcatheter treatment of thrombosed hemodialysis access grafts.

Thrombosis of access grafts is a frequent problem for patients being treated with long-term hemodialysis. Transcatheter techniques have recently been used in the primary management of failed dialysis grafts. This article reviews current methods for transcatheter treatment. Several thrombolytic techniques are discussed, including pharmacologic, pharmacomechanical, and mechanical methods. Methods for treatment of underlying graft stenosis are considered. Complications associated with these procedures are reviewed. The percutaneous techniques are compared among themselves and with standard surgical procedures for graft revision. Finally, several evolving methods for prevention of dialysis graft thrombosis are considered.

Catheterization, Peripheral↗

Pulse-spray pharmacomechanical thrombolysis of thrombosed hemodialysis access grafts: long-term experience and comparison of original and current techniques.

OBJECTIVE: Pulse-spray pharmacomechanical thrombolysis is an evolving method for the treatment of vascular occlusions in which a highly concentrated fibrinolytic agent is injected as a high-pressure spray directly into thrombus. The purpose of this retrospective study was to analyze our long-term experience with this technique for the treatment of clotted hemodialysis grafts and to compare the efficacy and safety of the original and current methods. SUBJECTS AND METHODS: Over 6 years, 284 cases of dialysis graft thrombosis were considered suitable for treatment with pulse-spray thrombolysis. The original technique involved the injection of highly concentrated urokinase directly into a clot through two crisscross catheters with multiple side holes. The current technique includes early fragmentation of residual clot with a balloon catheter, intrathrombic injection of heparin, mechanical treatment of a lysis-resistant clot at the arterial anastomosis, and routine administration of aspirin. After thrombolysis, underlying obstructions were treated with balloon angioplasty, atherectomy, or stents. The technical success, immediate clinical success, and frequency of complications for the entire population were analyzed. In addition, the results for 36 cases treated with the original technique were compared with the results for 37 recent cases treated with the current technique. RESULTS: Of 284 cases considered suitable for treatment, thrombolysis was not done in eight cases because the venous anastomosis could not be crossed. Thrombolysis was discontinued in two cases because of extravasation of contrast material. The technical success for all grafts considered for treatment was 96%; 92% of treated grafts remained patent for at least 24 hr. Major complications occurred in 1% of cases, and minor complications occurred in 9% of cases. The clinical efficacies of the original and current techniques were 86% and 92%, respectively. The mean thrombolytic agent infusion time was reduced from 44 +/- 20 min to 23 +/- 13 min (p < .001). The overall procedure time for the recently treated subgroup was 67 +/- 26 min. There was no significant difference in the frequencies of major and minor complications between the treatment subgroups. CONCLUSION: Pulse-spray pharmacomechanical thrombolysis is a reliable, rapid, and safe method for recanalization of occluded dialysis grafts. The current technique has been proven as safe and effective as the original technique but offers the advantage of a significant reduction in the time required for the infusion of thrombolytic agent.

Anastomosis, Surgical↗

Is thrombolysis of occluded popliteal and tibial bypass grafts worthwhile?

PURPOSE: We analyzed the short- and long-term results for patients undergoing thrombolysis of occluded infrainguinal bypass grafts at our institution over a 62-month period. METHODS: Thirty-one patients with 40 episodes of graft thrombosis in 33 grafts managed by thrombolysis were retrospectively reviewed. The effects of graft age, material, and anatomy, symptoms, treatment, anticoagulation, and occlusion duration were evaluated for impact on patency after thrombolysis. Dose and duration of therapy with use of the technique of pulse-spray thrombolysis was assessed. RESULTS: Thrombolysis successfully reestablished patency in 92% of grafts treated. Mean lysis time and urokinase dose were 118 minutes and 607,000 units, respectively. Responsible lesions were identified and treated by angioplasty or surgery in 35 of 37 cases. The patency rate after thrombolysis was 28% at 30 months, and the secondary patency rate was 46% at 18 months. Duration of occlusion, symptoms, treatment, graft anatomy, and prior graft revision did not impact on patency. Mean secondary patency was 21.5 months in grafts in place over 1 year and 7.0 months in grafts in place for less than 1 year. Mean secondary patency was 23.8 months in polytetrafluoroethylene grafts and 8.4 months in vein grafts. The limb salvage rate was 84% at 30 months, and the patient survival rate was 84% at 42 months. CONCLUSIONS: Pulse-spray thrombolysis is effective in rapidly recanalizing thrombosed infrainguinal grafts. Grafts failing in the first year after placement should generally be replaced, reserving thrombolysis and revision for grafts greater than 1 year old. Vein grafts tolerate thrombosis less well than synthetic conduits and have decreased long-term patency.

Adult↗

Overdilation of the Wallstent to optimize portal decompression during transjugular intrahepatic portosystemic shunt placement.

PURPOSE: To optimize shunt size with overdilation of the Wallstent during creation of a transjugular intrahepatic portosystemic shunt (TIPS). MATERIALS AND METHODS: A TIPS was created in 25 patients with variceal bleeding (n = 22) or intractable ascites (n = 3). All shunts were created with one or more Wallstents that were dilated with an 8- or 10-mm balloon. In 11 patients with inadequate portal decompression or persistent filling of varices, shunts were overdilated with a 12-mm balloon. RESULTS: Mean portosystemic pressure gradient fell from 18.0 mm Hg +/- 6.4 (standard deviation) to 6.8 mm Hg +/- 2.8 after shunt placement. In 11 patients in which shunts were overdilated, the mean gradient fell from 12.7 mm Hg +/- 5.6 after 10-mm dilation to 6.9 mm Hg +/- 2.8 (P = .01) after 12-mm dilation. In six, variceal filling occurred after 10-mm dilation but diminished or ceased after overdilation. Stent disruption did not occur. New or worsened encephalopathy occurred in four of 14 patients with 10-mm and six of 11 patients with 12-mm shunt dilation and responded to medical therapy in all but two. CONCLUSION: Overdilation of the Wallstent during TIPS placement is effective and safe in patients with inadequate portal decompression after 10-mm shunt dilation.

Adult↗