Venous thrombolysis and venous angioplasty

Venous thrombosis of the upper extremities was successfully lysed in 7 patients using selective infusion of urokinase. Selective lysis requires a lower dosage of urokinase and has a lower rate of side effects. Venous angioplasty was applied in 2 patients with stenoses of the subclavian vein, 3 with stenosis in dialysis shunts, and 1 patient with a long stenosis of the iliac vein. Venous angioplasty was successful and particularly useful in dialysis shunt stenoses.     

The importance of preoperative evaluation of the subclavian vein in dialysis access planning.

Adequate venous outflow is critical to the proper function of a vascular-access graft (arteriovenous fistula) used for chronic hemodialysis. Stenosis of the subclavian vein can significantly compromise this venous outflow. The development of such subclavian vein stenoses has been associated with the prior placement of temporary subclavian vein dialysis catheters. We evaluated the importance of preoperative detection of these stenoses before placement of a permanent vascular-access graft in the upper extremity. Upper extremity venography was performed before placement of a permanent vascular-access graft in 43 patients. A total of 62 extremities were evaluated. A 40% prevalence of moderate or severe subclavian vein stenosis was found in patients with prior or existing temporary dialysis catheters in the subclavian vein. No stenoses were found in patients without a history of dialysis catheters in the subclavian vein. This difference in the prevalence of subclavian vein stenosis is statistically significant (p less than .001). In no case was the stenosis suspected clinically. Before placement of a permanent vascular-access graft, the subclavian vein should be evaluated in all patients with a history of a temporary dialysis catheter in the subclavian vein. The use of sites other than the subclavian vein for temporary dialysis is strongly encouraged.     

External beam irradiation as an adjunctive treatment in failing dialysis shunts

PURPOSE: To evaluate the utility of low-dose irradiation as adjunctive treatment for failing dialysis shunts related to stenoses. MATERIALS AND METHODS: Thirty-one patients with 41 lesions in their dialysis shunts were successfully enrolled for this study. After imaging of the shunt and calculation of venous stenoses, each patient was randomized into one of two segments of the protocol: (i) angioplasty and/or stent placement alone, and (ii) angioplasty and/or stent placement followed by external beam irradiation. All patients with significant venous stenoses (> or =50%) were treated with appropriately sized PTA (percutaneous transluminal angioplasty) and Wallstents. Patients randomized to the external irradiation segment underwent localized irradiation via a Theratron cobalt unit of 7 Gy 0-24 hours and 24-48 hours after intervention. Those patients randomized to the control group received no additional treatment. Clinical follow-up included resumption of successful dialysis with appropriate hemodynamic parameters. Two follow-up shunt images were obtained, follow-up 1 (fu-1) from 90 to 179 days and follow-up 2 (fu-2) from 180 to 365 days. Percentages of significant recurrent stenoses, defined as greater than 50%, were recorded and re-treated as needed. RESULTS: Sixteen of the 31 patients underwent external beam irradiation. There were 21 lesions in the test group that underwent irradiation after intervention, and 20 lesions were treated with intervention alone. There were seven native arteriovenous fistulas and 24 Gore-tex grafts. All stenoses were either venous outflow stenoses (68%) or central stenoses (32%). The authors utilized chi2 analysis to compare restenoses rates between the control and irradiated groups at fu-1 (P<.99) and fu-2 (P<.10). CONCLUSIONS: Although the results show that external beam irradiation has minimal effects on the restenoses of dialysis grafts when used in conjunction with PTA and stent placement, further studies with a larger, more homogenous population are needed to assess the trend of improving patency rates after external beam irradiation.     

Stenoses in dialysis fistulas: treatment with percutaneous angioplasty

Percutaneous transluminal angioplasty (PTA) was performed on 30 stenotic lesions in 25 dialysis access fistulas. The fistulas were in 23 patients with a mean age of 53 years. Lesions were detected with angiography within a few days after poor flow or increased venous pressure was documented during dialysis. Twenty-two lesions were in patients with polytetrafluoroethylene graft fistulas, five were in patients with bovine carotid fistulas, and three were in patients with endogenous arteriovenous fistulas. There were 28 venous stenoses (20 at the anastomotic site and eight more proximally) and two arterial stenoses. The overall success rate was 80%, with a 6-month patency of 76% and a mean patency after PTA of 9.4 months. Among the venous lesions, the success was 100% for proximal lesions and 71% for anastomotic lesions. There were two technical failures, which required surgery for revision of the fistulas, and four self-limited hematomas. PTA is a safe and effective treatment for stenoses in dialysis fistulas, particularly for lesions remote from the anastomotic sites.     

Percutaneous transluminal angioplasty of stenotic lesions in dialysis vascular accesses

Forty-five stenoses behind arteriovenous fistulas in 35' haemodialysed patients were treated with percutaneous transluminal angioplasty (PTA). Immediate stenoses dilatation results in relation to the AVF type were haemodynamically significant in 40 cases (88%), with poorer results on bovine heterograft stenoses. Dilatation results in relation to the site of the lesion showed haemodynamically efficient angioplasty on stenoses next to the anastomosis (67.5%) but a poor result on distal lesions (4 cases). We observed 4 cases of thrombosis but 2 recovered after treatment, one after local fibrinolytic perfusion one after surgical thrombectomy. Follow-up over a period of one to 18 months (mean 8 months) including angiography and appreciation of the dialysis quality were performed in 30 patients who had a successful dilatation. PTA appears to be a technically feasible and clinically effective method of treating stenoses lying on the venous limb fistula in patients on chronic haemodialysis.     

Cutting balloon angioplasty for primary treatment of hemodialysis fistula venous stenoses: preliminary results

PURPOSE: To assess the efficacy of the cutting balloon as the primary tool in percutaneous transluminal angioplasty of hemodialysis access stenoses. MATERIALS AND METHODS: A prospective study of symptomatic patients with stenoses of 50% or more in their hemodialysis accesses was undertaken. Provided that no contraindication to the use of cutting balloons existed, the stenoses were treated with the cutting balloon with use of a maximum of a 1:1.1 ratio between expected vessel diameter and balloon diameter. In cases in which dilation to the full diameter of the cutting balloon left a greater than 30% residual stenosis, postprocedural dilation with conventional balloons was carried out. Patient access function was followed. Twenty-nine patients with 42 stenoses have now reached 6 months of follow-up after cutting balloon angioplasty. RESULTS: Technical and clinical success rates were 100%. Slight local extravasation occurred in three cases: two had continued pain after the balloon was deflated and were therefore treated with balloon compression with resolution of symptoms and angiographic findings. In two cases, elastic recoil required stent placement to correct the stenosis. At 6 months, 22 patients (76%) remain in the primary patency category. Inclusion of those with primary assisted patency yields 26 patients (90%), and an additional patient had secondary patency, for a total of 93%. Two patients died of causes not directly related to dialysis. CONCLUSION: The high degree of technical and clinical success likely reflects the lack of major complications. The 6-month follow-up results match those of other series. Further follow-up will show whether this technique produces better results over the long term.     

血透内瘘闭塞的介入治疗

目的讨论使已闭塞的血透内瘘恢复功能的介入治疗方法。方法4例患者采用PTD行经皮机械血栓切除术、尿激酶血栓溶解及时严重狭窄的静脉流出道、动静脉吻合口行PTA治疗共进行了5次介入治疗。结果4例患者的血透内瘘术后即刻恢复了功能,造影示内瘘血流通畅,吻合口有震颤、杂音明显,静脉明显搏动。结论采用多种介入方法治疗闭塞的血透内瘘是一种安全、简单、有效的方法,尤其适合门诊病人的治疗。     

Using pullback pressure measurements to identify venous stenoses persisting after successful angioplasty in failing hemodialysis grafts

OBJECTIVE: We used pullback pressure measurements to identify venous stenoses persisting after angioplasty of failing hemodialysis grafts. MATERIALS AND METHODS: Fifty angioplasty procedures were performed in 32 patients with elevated venous pressures at dialysis. Grafts were initially evaluated on digital subtraction angiography, and all stenoses measuring greater than 50% on angiography underwent angioplasty. In successful cases (residual stenosis < 30%), pullback pressure measurements were obtained from the superior vena cava to the graft to identify hemodynamically significant (> 10 mm Hg) stenoses. These lesions were then treated with repeated angioplasty. RESULTS: Hemodynamically significant stenoses with a gradient range of 10-27 mm Hg (mean, 16 mm Hg) were found in nine (18%) of 50 procedures. All gradients occurred at sites of previous angioplasty. Repeated angioplasty of these stenoses performed with larger angioplasty balloons reduced gradients to less than 3 mm Hg in six stenoses and to 5 mm Hg in three stenoses. In this subgroup, primary patency was eight (89%) of nine stenoses at 1 month and 2 months and five (56%) of nine stenoses at 6 months. Using life table analysis, we found that primary patency of the entire population was 84% at 1 month, 66% at 2 months, and 47% at 6 months. The mean time between interventions was 6 months, and the thrombosis rate was 0.32 per year. CONCLUSION: Pullback pressure measurements are a useful adjunct to angiography to evaluate the hemodynamic results of angioplasty in patients with failing hemodialysis grafts.     

The porcine hemodialysis access model

PURPOSE: To create a porcine hemodialysis access model that reliably reproduces intimal hyperplasia (IH) of the outflow vein similar to that which causes access failure in human patients undergoing dialysis treatments. MATERIALS AND METHODS: Surgical technique for creation of side-to-side iliac-artery-to-ipsilateral-iliac-vein (IAV) native fistulas and IAV conduits was optimized in three standard-bred pigs. Persistent patency of fistulas and conduits was demonstrated in two additional pigs allowed to survive for 1 week. IAV fistulas and contralateral 2-cm polytetrafluoroethylene IAV conduits were created in five additional pigs. Venous outflow from these fistulas and conduits was evaluated with venography and intravascular ultrasound (IVUS) immediately after creation (day 0) and at 2-week intervals for as long as 64 days. Animals were killed at 30 days (n = 1), 42 days (n = 2), or 64 days (n = 2), and the arteries, veins, and conduits were evaluated histologically. RESULTS: IAV native fistulas remained patent until the animals' death and conduits remained patent for at least 14 days in four of five pigs; both the fistula and conduit likely occluded before 16-day follow-up in the fifth pig. At 42-64 days, venography demonstrated maximum fistula outflow vein diameter stenoses of 53%-76% and maximum conduit outflow vein stenoses of 44%-84%, and IVUS demonstrated maximum area stenoses of 64%-86% and 43%-82%, respectively. Three of five conduits occluded, one before 16-day follow-up, one between 14 and 28 days, and the other after 42 days. Histologic sections demonstrated IH predominantly affecting the veins at the anastomoses and central (cephalad) to the anastomoses in all pigs. CONCLUSION: This porcine model reproduces IH in the fistula or conduit outflow vein with measurable stenosis. Such a model might allow relevant preclinical evaluation of interventional devices and techniques intended to reduce the effects of IH in human patients undergoing dialysis treatments.     

Venöse Interventionen

This article focuses on the percutaneous treatment options of venous thromboses and occlusions. Interventional therapy modalities for mediastinal, brachial, axillar, cerebral, and mesenteric thromboses are reviewed. Stenoses of the superior vena cava are most often caused by mediastinal malignomas. Balloon angioplasty together with stent implantation is an effective method for revascularisation in cases of upper venous congestion. Benign central venous stenoses are common in dialysis patients for whom interventional therapy using balloon angioplasty has proven excellent results. In the treatment of insufficient dialysis access, percutaneous techniques represent the first-choice option. Regarding cerebral and mesenteric thrombosis, interventional therapy is restricted to selected individual cases.     

Venous interventions. Part 2: Thromboses of the upper torso and mesenteric veins

This article focuses on the percutaneous treatment options of venous thromboses and occlusions. Interventional therapy modalities for mediastinal, brachial, axillar, cerebral, and mesenteric thromboses are reviewed. Stenoses of the superior vena cava are most often caused by mediastinal malignomas. Balloon angioplasty together with stent implantation is an effective method for revascularisation in cases of upper venous congestion. Benign central venous stenoses are common in dialysis patients for whom interventional therapy using balloon angioplasty has proven excellent results. In the treatment of insufficient dialysis access, percutaneous techniques represent the first-choice option. Regarding cerebral and mesenteric thrombosis, interventional therapy is restricted to selected individual cases.     

MR angiography of the forearm--visualization of the internal dialysis shunt

Phase contrast MR angiography (MRA) of the forearm was performed in 10 healthy volunteers and 3 patients with chronic renal failure. In all volunteers, MRA demonstrated two arteries (radial artery and ulnar artery) and several cutaneous veins. In patients with chronic renal failure, internal dialysis shunts were clearly visualized and the stenoses of the shunts which were confirmed by later DSA were also well defined. It is concluded that MRA may be a valuable technic in the evaluation of internal dialysis shunts.     

The site of atheromatosis in the subclavian and vertebral arteries and its implication for angioplasty

We analysed the site of plaques and stenoses in the subclavian and vertebral arteries, to improve the safety of percutaneous transluminal angioplasty (PTA) in high-risk patients. These lesions were assessed on arteriograms of 35 patients with stenoses and occlusions of the subclavian and vertebral arteries; the degree of stenoses was measured. Of 19 subclavian artery stenoses 17 (89 %) were in the segment proximal to the vertebral artery; 30 (79 %) of 38 vertebral artery stenoses were on the medial wall. With this knowledge, a double-balloon technique using a simultaneous transbrachial and transfemoral approach for angioplasty of high-risk subclavian or combined subclavian and vertebral artery stenoses and occlusions was used successfully in seven patients. This new technique may broaden the endovascular therapeutic possibilities in the rare but dangerous situation where plaque extends directly from the stenotic subclavian artery into the origin of the vertebral artery. Received: 1 July 1998 Accepted: 15 December 1998     

Treatment of venous outflow stenoses in thigh grafts with Wallstents.

OBJECTIVE: We studied the effectiveness of Wallstent deployment to treat elastic femoral and iliac vein stenoses in patients with lower extremity hemodialysis grafts. MATERIALS AND METHODS: Between August 31, 1992, and October 13, 1997, 44 metallic stents were deployed in 20 patients to treat stenoses exhibiting immediate, significant elastic recoil after angioplasty. Twenty-four stents were placed in the femoral and saphenous veins, and the remaining 20 stents were placed in the iliac veins. Follow-up was provided by the nephrology and surgical service at our institution and by electronic review of patients' charts. The follow-up period was from August 31, 1992, until October 1, 1998. RESULTS: Stents were successfully inserted and stenotic lesions dilated in 100% of procedures. Each patient successfully completed at least one session of dialysis after the procedure. The primary patency rate of stents was 87% 60 days after the procedure, 51% 180 days after, 39% 1 year after, and 20% 2 years after. The secondary patency rate was 95% 60 days after the procedure, 92% 180 days after, 81% 1 year after, and 62% 2 years after. Complications were limited to two graft infections that developed 5 and 7 days after stent placement. CONCLUSION: Treatment of elastic venous stenoses is effective in patients with lower extremity dialysis grafts using metallic stents. The patency rates of these devices placed in the iliac and femoral veins are comparable with those of metallic stents placed in upper extremity and central veins.     

Cutting Balloon angioplasty for the treatment of haemodyalisis vascular accesses: midterm results

PURPOSE: The purpose of this study was to assess the effectiveness of Cutting Balloon angioplasty in the treatment of stenoses in haemodialysis arteriovenous accesses. MATERIALS AND METHODS: Over the past 2 years, we have observed 80 patients with stenotic haemodialysis accesses; 24 of these (mean age 66.4 years, range 50-81) with 26 stenoses of 24 accesses (21 Cimino-Brescia fistulas and 3 dialysis loops) were selected for Cutting Balloon angioplasty. In 11 cases, the Cutting Balloon device was used after failure to dilate the access with a high-pressure balloon whereas in 15 cases (10 focal stenoses and 5 restenoses), it was used as a first choice. Two Cutting Balloon devices had a diameter of 8 mm, two of 7 mm, 11 of 6 mm, eight of 5 mm and one of 4 mm. The follow-up was performed by colour Doppler ultrasound (CDUS) and clinical assessment at 1, 3, 6, 12, 18 and 24 months. RESULTS: In all patients, postprocedure angiography demonstrated immediate technical success. No periprocedural complications occurred. Follow-up examinations (range 3-24 months, mean 18.2 months) demonstrated patency of the vascular access and its good functioning during dialysis in 23/24 cases (95%). Only in one case did we observe a haemodynamically significant restenosis, which was treated again with Cutting Balloon angioplasty. CONCLUSIONS: Cutting Balloon angioplasty is safe and effective in the treatment of haemodialysis access stenosis, especially in cases of severe stenosis, with low restenosis rate both in the short and medium term.     

Stent Grafts for Central Venous Occlusive Disease in Patients with Ipsilateral Hemodialysis Access

PurposeTo assess long-term outcomes of stent grafts in patients with symptomatic central venous stenoses and occlusions ipsilateral to hemodialysis grafts or fistulas.Materials and MethodsThe study included 52 of 55 consecutive patients with symptomatic stenoses of the central veins draining upper limb dialysis access grafts or fistulas treated with stent grafts. Indications for stent grafts were poor angioplasty results, rapid recurrence, or total occlusion. Endpoints were lesion patency and access patency following intervention. Mean follow-up was 25 months with a median of 24 months and 1.25 additional procedures per patient year. Patency rates were calculated using Kaplan-Meier analysis.ResultsAll stent grafts were successfully deployed. The lesion patency rates at 6, 12, 24, and 36 months after intervention were 60%, 40%, 28%, and 28%. The access patency rates at 6, 12, 24, and 36 months after intervention were 96%, 94%, 85%, and 72%. There was one major complication and no minor complications. In 40 patients (77%), the internal jugular vein confluence was covered by the stent graft. In five patients, the dialysis circuits became occluded, with no clinical sequelae in four; one patient was lost to follow-up. The contralateral brachiocephalic vein was covered in three patients (6%), preventing contralateral access construction in one patient.ConclusionsCentral vein stent graft placement in patients with hemodialysis access is associated with prolonged access patency. Coverage of major vein confluences, which occurred in 83% of the patients in this series, can compromise future access and should be avoided whenever possible by careful technique.     

Vascular rupture complicating transluminal angioplasty applied on a failed dialysis vascular access in a patient under chronic steroid therapy

We report a case of venous rupture complicating percutaneous transluminal angioplasty (PTA) applied on a failed dialysis vascular access (VA) in a patient on chronic steroid therapy. This complication resulted in a rapidly growing hematoma which was successfully controlled by a prolonged reinflation of the balloon catheter at the angioplasty site. The absence of oversizing of the balloon catheter and the low inflation pressure at which the perforation occurred suggest a vessel fragility which was probably induced by a long-standing steroid therapy. In dialysis patients in whom steroid therapy does not represent an infrequent therapeutic modality, this potential risk of vascular rupture should be carefully weighted while treating VA stenoses with the use of PTA. Received 10 January 1996; Revision received 18 March 1996; Accepted 23 July 1996     

Colour doppler flow imaging of the carotid arteries

Summary 53 patients with carotid artery atherosclerosis were examined by colour Doppler flow imaging. These results were compared with real time duplex sonography and continuous wave Doppler sonography. In 48 low degree stenoses (<50%) the B-mode showed 36 smooth and 12 ulcerated plaque surfaces. In 24 high degree stenoses (>50%) 10 plaques were smooth and 14 ulcerated. In the low degree stenoses, which exhibited smooth surfaces in B-mode examination, colour flow Doppler showed nine additional cases with turbulences in the area of the stenotic site. This indicates that plaque ulcerations in low degree stenoses are underestimated. In contrast, in nearly all cases with high degree stenoses marked turbulences could be demonstrated by colour Doppler flow imaging independent of the B-mode showing regular or ulcerated plaque surfaces. Additionally, the duplex ultrasound diagnosed a carotid artery occlusion in 11 cases, but the colour coded Doppler was able to assess a remaining blood flow in two out of these 11 cases. Our results suggest that the colour Doppler flow imaging as a noninvasive technique is an advantage in diagnosing plaque ulcerations and it is more precise in diagnosing carotid occlusions than duplex-sonography is.     

Placement of venous stents: clinical experience with a self-expanding prosthesis.

A self-expanding vascular prosthesis was used to treat 20 venous stenoses or occlusions in 13 patients. The lesions were caused by tumor (n = 5), postoperative fibrous scars (n = 2), and chronic hemodialysis fistulas (n = 13). Follow-up ranged between 6 weeks and 53 months (mean follow-up, 14.9 months). Acute occlusion occurred in two stents, one within a tumor stenosis and one in a dialysis shunt after 3 days and 2 days, respectively. Balloon angioplasty, thrombolysis, and aspiration in the first case and balloon angioplasty and thrombolysis in the second case successfully restored patency. Definite occlusion occurred in these two patients after 8 weeks and 5 months, respectively. Ten secondary interventions were performed in three patients with 10 restenoses who had stenotic arm veins in chronic hemodialysis at presentation. Five of seven patients who received treatment for stenoses associated with hemodialysis underwent successful kidney transplantation 5-27 months after placement of vascular stents. Both patients who received treatment for benign strictures had patent stents at follow-up examinations performed at 45 and 53 months, respectively. Four of five stents placed for malignant stenoses were patent at venography (n = 3) or autopsy (n = 1).     

Comparison of SMART stent placement for arteriovenous graft salvage versus successful graft PTA

PURPOSE: To compare the SMART (shape memory alloy recoverable technology) stent with percutaneous transluminal angioplasty (PTA) alone in hemodialysis access venous stenoses. MATERIALS AND METHODS: A prospective, nonrandomized study was undertaken in 60 patients with dysfunctional polytetrafluoroethylene dialysis grafts. Indications for stent placement were acute PTA failure, rapid restenosis, and vessel perforation. The primary endpoint was improved graft patency in patients treated with stents compared with that in patients whose disease responded to PTA alone. The secondary endpoints were lower postprocedural midgraft pressures and similar complication rates compared with PTA alone. RESULTS: The key venous stenosis was at the graft-to-vein anastomosis in all but two patients. Thirty-five patients showed a response to PTA alone. Sixteen patients received stents for stenoses greater than 30% after angioplasty, six for rapidly recurrent stenosis, and three for venous rupture. Nine patients received stents across the level of the elbow joint. Stenosis after intervention was significantly less frequent in the stent group (7% vs 16%; P = .001), but the midgraft systolic pressure ratios did not significantly differ. The clinical success rates were 100% after stent implantation and 97% after PTA alone. Except for venous rupture, there were no procedure-related complications, and, excluding early graft thrombosis, there were no complications at 30 days. A single stent fracture was found on follow-up. The mean primary graft patency times were 5.6 months after PTA and 8.2 months after stent treatment (P = .050). When stents were placed across the level of the elbow joint, the mean primary graft patency time was 8.9 months. CONCLUSION: Implantation of the SMART stent is safe and effective for the treatment of residual or rapidly recurrent dialysis access venous stenoses and is associated with better patency than PTA alone.