Thomas M. Vesely

Central Venous Catheter Tip Position: A Continuing Controversy

There is continuing debate among physicians, nurses, and federal regulatory agencies regarding the correct position for the tip of a central venous catheter. The traditional approach has been to place the catheter tip within the superior vena cava. However, many interventionalists believe that the performance and durability of the catheter will be improved by positioning the catheter tip within the upper right atrium. Recently, this variability in clinical practice has become an increasingly divisive issue among physicians who insert these catheters and nurses who use them. This article is intended to elucidate the controversial issues and provide a brief review of the extensive literature on this important topic.

Lower Extremity Venous Thrombolysis with Adjunctive Mechanical Thrombectomy

PURPOSE To evaluate the use of adjunctive mechanical thrombectomy (MT) with pharmacologic catheter-directed lower extremity venous thrombolysis. MATERIALS AND METHODS Catheter-directed thrombolysis with adjunctive MT was used to treat 28 symptomatic limbs in 20 patients (22 procedures) with lower extremity deep vein thrombosis (DVT) between August 1997 and July 2001. Procedural success, major bleeding, thrombolytic infusion time, and total thrombolytic agent dose were recorded. RESULTS Procedural success was achieved in 23 of 28 limbs (82%). Fifteen patients (18 limbs) received iliac vein stents. Major bleeding was observed after three of 22 procedures (14%) and resulted in transfusion in two patients and endometrial ablation in the third patient. Mean per-limb infusion time was 16.8 hours +/- 12.8. Mean per-limb total doses were lower than those reported in published studies of DVT thrombolysis: 2.67 million U +/- 1.60 urokinase, 18.4 mg +/- 10.7 tissue plasminogen activator, and 13.8 U +/- 6.9 reteplase. Venographic analysis demonstrated minimal thrombus removal (26.0% +/- 24.1) when using MT alone, compared with substantial thrombus removal (62.0% +/- 24.9) when using MT after pharmacologic thrombolytic agents had been administered (P =.006). CONCLUSION The use of adjunctive MT to augment pharmacologic catheter-directed DVT thrombolysis provides comparable procedural success and may reduce the required thrombolytic dose and infusion duration.

Pharmacomechanical thrombolysis and early stent placement for iliofemoral deep vein thrombosis

PURPOSE To evaluate an approach to the treatment of iliofemoral deep vein thrombosis (DVT) that included pharmacomechanical catheter-directed thrombolysis with reteplase and the Helix mechanical thrombectomy device, followed by early stent placement. MATERIALS AND METHODS During 3-year period, 23 symptomatic limbs in 18 patients with iliofemoral DVT were treated with reteplase catheter-directed thrombolysis. After an initial infusion of 8 to 16 hours, any residual acute thrombus over a long segment (> 10 cm) was treated by maceration with use of the Helix thrombectomy device. Residual short-segment (< 10 cm) iliac vein thrombus and/or stenosis were treated with stent placement. Technical success, clinical success, complications, thrombolytic infusion time, total thrombolytic agent dose, fibrinogen level changes, and late limb status were retrospectively analyzed. RESULTS Technical success was achieved in 23 of 23 limbs (100%). Clinical success was achieved in 22 of 23 limbs (96%). Complete or partial thrombolysis was observed in 19 of 23 limbs (83%). Major bleeding was observed in one patient (6%) and necessitated blood transfusion. Mean per-limb thrombolytic infusion time and total dose were 19.6 hours +/- 8.1 and 13.8 U +/- 5.3 reteplase, respectively. Mean serum fibrinogen nadir and percentage drop in serum fibrinogen were 282 mg/dL +/- 167 and 47% +/- 24%, respectively. Late (mean, 19.8 +/- 11.6 months) modified Venous Disability Scores were 0 (none) for six limbs, 1 (mild) for 10 limbs, 2 (moderate) for two limbs, and 3 (severe) for no limbs. CONCLUSION In a preliminary experience, pharmacomechanical catheter-directed iliofemoral DVT thrombolysis with early stent placement was safe and effective.

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

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

Use of the Peripheral Cutting Balloon to Treat Hemodialysis-related Stenoses

PURPOSE To compare the effectiveness and safety of use of the peripheral cutting balloon (PCB) versus standard percutaneous transluminal angioplasty (PTA) for the treatment of hemodialysis-related stenoses. MATERIALS AND METHODS This prospective, randomized multicenter clinical trial included 340 patients with stenotic or thrombosed hemodialysis grafts who were randomized to receive treatment with the PCB or PTA for venous outflow stenosis. One hundred seventy-three patients underwent treatment with the PCB, 101 with stenotic grafts and 72 with thrombosed grafts. PTA was used to treat 167 patients, 94 patients with stenotic grafts and 73 with thrombosed grafts. The follow-up period extended for 6 months. RESULTS The procedural success rates were 80.8% and 75.4% for the PCB and PTA groups, respectively (P = .24). With use of the PCB, the primary patency rates of the target lesions were 84.3%, 65.8%, and 47.9% at 1 month, 3 months, and 6 months, respectively. With PTA, the primary patency rates of the target lesions were 77.7%, 63.4%, and 40.5% at 1 month, 3 months, and 6 months, respectively. The primary patency rates of the entire vascular access circuit were 82.6%, 61.0%, and 43.3% at 1 month, 3 months, and 6 months, respectively, with use of the PCB. For patients who were treated with PTA, the primary patency rates of the vascular access circuit were 75.9%, 61.0%, and 36.3% at 1 month, 3 months, and 6 months, respectively. When comparing the PCB and PTA, there was no difference in the 6-month primary patency rates in the target lesion (P = .373) or the entire vascular access circuit (P = .531). There were nine device-related complications in the PCB group (5.2%): five venous ruptures (2.9%), three venous dissections (1.7%), and one case of thrombosis (0.6%). There were no device-related complications in the PTA group. CONCLUSION This prospective, randomized trial comparing use of the PCB versus standard PTA for treatment of hemodialysis-related venous stenoses demonstrated that the PCB provides equivalent 6-month patency to PTA for stenotic and thrombosed grafts.

Use of Stent Grafts to Repair Hemodialysis Graft–related Pseudoaneurysms

PURPOSE To review the authors early experience with stent grafts to repair hemodialysis graft-related pseudoaneurysms. MATERIALS AND METHODS Eleven patients had undergone insertion of a stent graft to repair a pseudoaneurysm arising from a PTFE hemodialysis graft. The study group consists of seven women and four men with a mean age of 50.7 years. The primary indications for stent graft placement were: rapid enlargement of a pseudoaneurysm in four patients, difficulty with cannulating the graft in two patients, high risk of acute rupture in three patients, persistent bleeding from the pseudoaneurysm in one patient, and one was incidentally discovered during diagnostic fistulography. In 10 of the 11 patients, the pseudoaneurysm arose from the arterial limb of a loop-configuration graft. A stent graft was successfully deployed in all patients. The radiological and surgical records were reviewed. RESULTS The Viabahn endoprosthesis was successfully inserted and deployed in all 11 patients. Six patients underwent subsequent interventions, which ended primary patency at 39 days, 40 days, 63 days, 104 days, 120 days, and 327 days after insertion of the stent graft. However, no additional interventions have been performed in five patients and primary patency continues. In these five patients the interval of continuing primary patency is 55 days, 92 days, 103 days, 139 days, and 196 days. In this small group of patients the primary patency rate is 71% at 3 months and 20% at 6 months. DISCUSSION Early experience has demonstrated that a stent graft can successfully exclude a pseudoaneurysm from a hemodialysis graft and may prevent further enlargement and decrease the likelihood of rupture. However, in two of these 11 patients, the large pseudoaneurysm remained problematic and required subsequent surgical repair.

Air Embolism during Insertion of Central Venous Catheters

PURPOSE To determine the clinical consequences of air embolism occurring during insertion of central venous catheters. MATERIALS AND METHODS A computer search of our interventional radiology database revealed that 11,583 central venous catheters were inserted between January 1, 1995 and August 1, 2000: 7,178 were nontunneled and 4,404 were tunneled. Air embolism was reported to have occurred in 15 patients. Air embolization was recognized by audible air aspiration during catheter insertion or by fluoroscopic visualization of air within the right atrium or pulmonary artery. The radiology reports and medical records of these 15 patients were reviewed. RESULTS All 15 patients had an air embolism occur during insertion of a tunneled central venous catheter. These included eight Ash catheters, five chest wall ports, one Tesio catheter, and one Pheres-Flow catheter. Four patients remained asymptomatic. Six patients had mild symptoms that quickly resolved with supplemental oxygen. Four had moderate symptoms that also resolved with supplemental oxygen. One patient died acutely as a result of the air embolism. CONCLUSION Air embolism is a rare but potentially fatal complication of central venous catheter procedures. In our series, all occurred during insertion of a tunneled catheter through a peel-away sheath. The administration of supplemental oxygen was an effective treatment in the majority of patients.

Guidelines for Venous Access in Patients with Chronic Kidney Disease A Position Statement from the American Society of Diagnostic and Interventional Nephrology 1 Clinical Practice Committee and the Association for Vascular Access 2

At the time of hemodialysis vascular access evaluation, many chronic kidney disease patients already have iatrogenic injury to their veins which impedes the surgical construction of an arteriovenous fistula (AVF). Achieving the important goal of a greater prevalence of arteriovenous fistulae in the US hemodialysis population will require identification of those patients prior to reaching end‐stage renal disease and an educational and procedural system for preserving their veins.

Prospective Anatomic Study of the Inferior Vena Cava and Renal Veins: Comparison of Selective Renal Venography with Cavography and Relevance in Filter Placement

PURPOSE To compare the sensitivity of selective renal venography with that of cavography in the detection of variant anatomic structures of the renal vein that may affect the placement of inferior vena caval (IVC) filters and to define IVC dimensions. PATIENTS AND METHODS Flush cavography, selective bilateral renal venography, and bilateral iliac venography were performed in 108 patients referred for IVC filter placement or vena cavography. Infrarenal IVC length and width were determined with a sizing catheter during cavography. Anomalies were considered significant if they altered placement or selection of the vena cava filter or if they represented a potential collateral pathway for clot to bypass a filter. RESULTS Variant anatomic structures in the renal vein were found in 11% of patients with cavography and in 37% of patients with selective renal vein injection. Detected anomalies included circumaortic veins (n = 11), multiple veins (n = 25), retroaortic veins (n = 2), and a partially duplicated IVC (n = 1). Selective venography depicted anomalies not suspected at standard cavography in 28 cases (26%); in 20 cases (18% of population) they were significant. The average infrarenal width was 20 mm on the anteroposterior view and was 17 mm on the lateral projection. CONCLUSION IVC anomalies are common, and selective renal venography can depict significant anomalies in renal vein anatomic structures not shown at standard cavography.

Arterial Problems Associated with Dysfunctional Hemodialysis Grafts: Evaluation of Patients at High Risk for Arterial Disease

PURPOSE To retrospectively review the incidence and types of arterial problems associated with dysfunctional hemodialysis grafts in patients who are at high risk for peripheral arterial disease. MATERIALS AND METHODS During the 1-year period from February 2001 to February 2002, 40 patients with polytetrafluoroethylene hemodialysis grafts underwent upper extremity arteriography to evaluate arterial inflow to the vascular access. The indication for arteriography was based on the presence of at least two of the following risk factors for peripheral vascular disease: diabetes mellitus, hypertension, and age greater than 65 years. Thirty-three of the 40 patients were women and the median age was 65 years. Thirty-three patients had forearm loop-configuration grafts and seven had upper-arm grafts. RESULTS Upper extremity arteriography revealed 13 arterial inflow lesions in 11 of the 40 patients (28%). Ten patients had stenoses at the arterial anastomosis. Two of these patients also had stenoses in the brachial artery. One patient had a single stenosis in the brachial artery. Eight of the 11 patients (73%) underwent angioplasty of seven arterial anastomotic stenoses and three brachial artery stenoses. Comparative analysis revealed that the presence of risk factors for atherosclerotic disease did not correlate with an increased incidence of arterial inflow problems. Surprisingly, patients with diabetes mellitus had a decreased likelihood (P =.03) of having an arterial abnormality. CONCLUSION Although the incidence of arterial anastomotic stenoses in our study group was higher than previously reported, patients undergoing hemodialysis who have risk factors for peripheral vascular disease do not have a high prevalence of native arterial lesions.