Are salvage techniques safe and effective in the treatment of peritoneal dialysis catheter-related exit-site and tunnel infections? A systematic review and description of the authors' preferred technique.

BACKGROUND: Peritoneal dialysis catheter (PDC)-related infections account for significant morbidity, PD disruptions and costs. Patients with refractory exit-site or tunnel track infections without peritonitis may need catheter removal and reinsertion which can be complicated by bleeding, organ injury, catheter failure or malposition. Some patients may need to switch to haemodialysis in such a setting. An alternative is a salvage procedure. The purpose of this systematic review is to evaluate the safety and efficacy of salvage techniques. METHODS: A comprehensive search of PubMed, Medline and Scopus databases was performed from inception to December 2021 in accordance with PRISMA guidelines. After a broad search, articles were stratified into two main categories for assessment: (1) cuff-shaving (CS) techniques and its variations of en-bloc resection (BR) and/or catheter diversion (CD) and (2) partial reimplantation with CD. RESULTS: A total of 409 patients (445 salvage procedures) from 20 studies were included in analysis. Of 409 patients, 234 patients (57.2%) underwent 251 (56.4%) CS procedures and its variations, 163 patients (39.9%) underwent 182 (40.9%) partial PDC reimplantations with CD and 12 patients (2.7%) underwent local curettage. Overall PDC salvage rate after intervention was 73.2%. Overall PDC removal rate attributable to infection was 26.8%. Overall complication rate attributable to the procedures was 2.7%, with the most common complication being dialysate leakage (n = 10) followed by PDC laceration (n = 1) and subcutaneous haematoma (n = 1). We also included a description of our technique of BR of infected tissue, CS and CD. In a series of six patients, the PDC salvage rate was 83.3% and median PDC survival after intervention was 10 months. CONCLUSION: PDC salvage techniques are relatively safe and provide reasonable catheter salvage rates in selected patients. Results of this review should lend weight to consideration of a salvage-first approach as an option in selected patients.

Effect of short-term low molecular weight heparin on patency following successful salvage of arteriovenous access with recurrent thrombosis.

AIM: This study aims to investigate the effect of low molecular weight heparin (LMWH) in maintaining the patency of arteriovenous (AV) access with recurrent thrombosis. METHODS: Following successful thrombectomy, 66 patients with recurrent thrombosis were included in the study. The primary, assisted primary and secondary patency rates of patients who received LMWH (n = 24) were compared with those who did not receive anticoagulant (n = 42) using Kaplan-Meier analysis. Cox-regression analysis was performed to investigate potential predictors of patency rates. RESULTS: The mean dose of enoxaparin used was 40 ± 13.1 mg or 0.74 ± 0.2 mg/kg daily for a median duration of 14 (IQR 7,28) days. The mean trough anti-Xa concentrations measured after two doses of LMWH was 0.17 ± 0.13 IU/mL. Kaplan-Meier analyses for mean primary, assisted primary and secondary patency rates of LMWH vs no anticoagulation groups were 149 (95% CI: 91 - 207) vs 87 (95% CI: 42-132) days (P < .006), 230 (95% CI: 142-320) vs 107 (95% CI: 62-150) days (P = .01) and 438 (299-579) vs 294 (95% CI: 197-392) days (P = .08) respectively. LMWH remained a significant protective predictor of primary (HR: 0.49; 95% CI: 0.25-0.86; P = .02) and assisted primary patency rates (HR: 0.51; 95% CI: 0.27-0.98; P = .04) after adjusting for patient age, access age, type of AV access, presence of peripheral vascular disease and haemoglobin levels. CONCLUSION: LMWH may improve short and mid-term patency rates for AV accesses with recurrent thrombosis.

The utility of endovenous cyanoacrylate glue ablation for incompetent saphenous veins in the setting of venous leg ulcers.

OBJECTIVE: Patients with venous leg ulcers (VLUs) represent the worse spectrum of chronic venous insufficiency (CVI). The Early Venous Reflux Ablation (EVRA) landmark trial published in 2018 demonstrated that early endovenous intervention results in faster healing of VLUs. We describe our post-EVRA experience using endovenous cyanoacrylate glue ablation (ECGA) to treat superficial venous reflux on an early basis and assess its efficacy and safety in the setting of VLUs. METHODS: There were 37 patients (39 legs, 43 truncal veins) with 43 discrete venous ulcers who underwent ECGA for CVI symptoms and VLUs. They received compression therapy and regular dressings for the VLUs postoperatively and were reviewed at 1 week, 3 months, 6 months, and 12 months after the procedure. Postoperative healing time for VLUs and complications were recorded along with the patient's satisfaction and postprocedure pain scores. RESULTS: The venous ulcers were all <30 cm2 before ECGA. The mean time for VLU healing from operation was 73.6 ± 21.9 days, and the primary occlusion rate of the CVI at both 1 week and 3 months was 100%. No major adverse events were observed except for one case of deep venous thrombosis. There was significant improvement in the revised Venous Clinical Severity Score postoperatively from 11 ± 1.63 (baseline) to 5.6 ± 1.37 (P < .001) at 3-month follow-up (on a scale of 0 to 27, with the severity of symptoms at a maximal 27). The visual analog scale scores for pain were low postoperatively, decreasing from a preoperative score of 6.84 ± 1.42 to 2.72 ± 1.59 (P < .001) at the 3-month follow-up (on a scale of 1-10, with 10 being the most severe pain). The median time to return to normal activities was 7 days (interquartile range, 5-7 days). CONCLUSIONS: ECGA together with compression therapy for VLUs is both safe and effective in this population of Asian patients. ECGA for patients with VLUs has excellent patient acceptability, minimal morbidity, and low recanalization rates at 12 months. Larger extensive studies and longer follow-up periods are required to validate the preliminary outcomes of this paper, and if it is proven to significantly improve ulcer healing rates, this will change the way we approach chronic venous ulceration.

Non-randomized safety and performance evaluation of the av-Guardian vascular access system.

INTRODUCTION: The ability to successfully cannulate the arteriovenous fistula reliably is a critical step in the delivery of hemodialysis therapy. The av-Guardian vascular access system (Advent Access, Singapore) is designed to overcome the technical barrier to establishing reliable blunt needle access in patients with mature arteriovenous fistula. METHODS: This was a first-in-man, prospective, non-randomized trial (registered on the Australian New Zealand Clinical Trial Registry (ACTRN12617000501347)) performed to assess the safety and feasibility of achieving repeatable successful cannulation via av-Guardian vascular access system to facilitate blunt needling in patients with mature arteriovenous fistula. The primary endpoints of the study included rate of successful hemodialysis sessions via av-Guardian vascular access system cannulation over 3 months and safety of the implants. RESULTS: A total of six patients (four patients with brachiocephalic and two with radiocephalic arteriovenous fistula) were enrolled in the study. A pair of av-Guardian vascular access system were implanted, one each at the arterial and venous cannulation sites, under local anesthesia. Overall, the rate of successful cannulation through the av-Guardian vascular access system over 3 months in 216 hemodialysis sessions was 98.1% (212/216) at the arterial site and 94.4% (204/216) at the venous site. Significantly, 90% and 85.5% of the cannulations at the arterial and venous site, respectively, were successful at first attempt. Blood flow rates within the arteriovenous fistula were unaffected by the devices. CONCLUSION: The results demonstrated the safety and feasibility of a subcutaneously implanted, extravascular device in achieving repeatable successful cannulation via a constant site, to facilitate blunt needling in matured arteriovenous fistula in limited number of patients.

The permanent catheter.

An elderly woman receiving hemodialysis via a right brachiocephalic arteriovenous fistula presented to the clinic for elective removal of a tunneled hemodialysis catheter inserted 5 years ago. The catheter had not been removed earlier at the patient's request. Removal was now unsuccessful in the clinic. Exploration in the operating room revealed the innominate vein had fibrosed around the length of the catheter. The procedure was abandoned, catheter cut short and the remnant left in situ. This case serves as a reminder to exercise caution if there is difficulty in removing the catheter even after the cuff is dissected free, and to remove them once a working fistula or graft is available. Failing which, the patient bears an unnecessary risk of line infection, or as in this case, the catheter may unintentionally end up what its common misnomer "perm-cath" alludes to--becoming truly "permanent."

Randomized clinical trial of cutting balloon angioplasty versus high-pressure balloon angioplasty in hemodialysis arteriovenous fistula stenoses resistant to conventional balloon angioplasty.

PURPOSE: To compare the efficacy and safety of cutting balloon angioplasty (CBA) versus high-pressure balloon angioplasty (HPBA) for the treatment of hemodialysis autogenous fistula stenoses resistant to conventional percutaneous transluminal angioplasty (PTA). MATERIALS AND METHODS: In a prospective, randomized clinical trial involving patients with dysfunctional, stenotic hemodialysis arteriovenous fistulas (AVFs), patients were randomized to receive CBA or HPBA if conventional PTA had suboptimal results (ie, residual stenosis > 30%). A total of 516 patients consented to participate in the study from October 2008 to September 2011, 85% of whom (n = 439) had technically successful conventional PTA. The remaining 71 patients (mean age, 60 y; 49 men) with suboptimal PTA results were eventually randomized: 36 to the CBA arm and 35 to the HPBA arm. Primary and secondary target lesion patencies were determined by Kaplan-Meier analysis. RESULTS: Clinical success rates were 100% in both arms. Primary target lesion patency rates at 6 months were 66.4% and 39.9% for CBA and HPBA, respectively (P = .01). Secondary target lesion patency rates at 6 months were 96.5% for CBA and 80.0% for HPBA (P = .03). There was a single major complication of venous perforation following CBA. The 30-day mortality rate was 1.4%, with one non-procedure-related death in the HPBA group. CONCLUSIONS: Primary and secondary target lesion patency rates of CBA were statistically superior to those of HPBA following suboptimal conventional PTA. For AVF stenoses resistant to conventional PTA, CBA may be a better second-line treatment given its superior patency rates.

Duplex ultrasonography arteriography as first-line investigation for peripheral vascular disease.

INTRODUCTION: The gold standard for evaluation of the lower extremity arterial tree is catheter angiography. Duplex arterial-occlusive imaging or duplex ultrasonography arteriography, a noninvasive technique, is used as the first-line investigation in patients with peripheral vascular disease at our centre. Based on the results of duplex imaging, patients who require angiographic intervention then proceed with simultaneous catheter arteriography and intervention. This study aimed to compare the results of duplex imaging alone as the first-line investigation against the eventual results of catheter angiography, and to assess the impact of the former on patients' clinical outcomes. METHODS: All cases involving patients who underwent duplex imaging followed by angiographic intervention, from May 2008 to February 2009, were discussed at weekly interdisciplinary meetings. Only patients who underwent lower limb imaging were included in the study. Those who were involved in grafts and stent surveillance studies, as well as those with incomplete duplex images were excluded. RESULTS: During the study period, 113 duplex imaging studies of the lower limb followed by percutaneous transluminal angioplasty were performed at our hospital for peripheral vascular disease. The iliac artery was visualised in 40 images, but could not be visualised in 73 images. There was a potential change in management in three cases due to radiological differences between the duplex images and angiography films. CONCLUSION: In our series, duplex imaging was found to be accurate enough to guide initial clinical management of patients with peripheral vascular disease. This modality is the preferred first-line investigation for such patients at our centre.

A rare case of septic deep vein thrombosis in the inferior vena cava and the left iliac vein in an intravenous drug abuser.

The patient was a 41 year-old Chinese female, a known intravenous drug abuser (IVDA), who presented with a left inguinal discharging sinus. A computed tomography (CT) scan showed inflammation in the left groin involving the left femoral vein and resulting in thrombus within the iliac veins extending to the distal portion of the inferior vena cava. Septic deep vein thrombosis is a well-recognized complication in intravenous drug abusers (IVDA) when large proximal veins are used for drug injection. Life threatening complications such as septic pulmonary embolism and right sided infective endocarditis may result. The aims of treatment are to prevent the septic thrombus from further embolisation and also to remove the thrombus. Treatment options include catheter directed thrombolysis, mechanical thrombectomy, endovascular treatment, surgical thrombectomy and excision of the involved venous segment.

The "SAFARI" technique using retrograde access via peroneal artery access.

The "SAFARI" technique or subintimal arterial flossing with antegrade-retrograde intervention is a method for recanalisation of chronic total occlusions (CTOs) when subintimal angioplasty fails. Retrograde access is usually obtained via the popliteal, distal anterior tibial artery (ATA)/dorsalis pedis (DP), or distal posterior tibial artery (PTA). Distal access via the peroneal artery has not been described and has a risk of continued bleeding, leading to compartment syndrome due to its deep location. We describe our experience in two patients with retrograde access via the peroneal artery and the use of balloon-assisted hemostasis for these retrograde punctures. This approach may potentially give more options for endovascular interventions in lower limb CTOs.

Bare nitinol stent enabled recanalization of long-segment, chronic total occlusion of superficial femoral and adjacent proximal popliteal artery in diabetic patients presenting with critical limb ischemia.

PURPOSE: To evaluate our experience of limb salvage with bare nitinol stent enabled recanalization of long length occlusions of superficial femoral artery (SFA) and adjacent proximal popliteal artery (PPA) in diabetic patients. METHODS: A total of 573 patients underwent 842 lower limb interventions from August 2006 to September 2008 at our institute. A retrospective review was done of diabetic patients undergoing recanalization of long length SFA/adjacent PPA (>10 cm) occlusions with self expanding bare nitinol stents evaluating their impact on limb salvage. RESULTS: Forty-four patients (mean age 65.2 years, M:F 25:19) underwent 49 long-length (>10 cm) SFA/PPA stenting procedures over a period of 26 months. Diabetics comprised 66% of patients (n=29, mean age: 63.7 years, M: F 19:10). The infrapopliteal distal run-off in this diabetic subgroup comprised one vessel (n=14/29, 48%), two vessels (n=12/29, 41%), and three vessels (n=3/29, 10%). The spectrum of critical limb ischemia included rest pain (n=8), ulcer (n=7) and gangrene (n=14). The lengths of occlusions recanalized were 10-39 cm. A total of 58 stents (individual length 10-17 cm, average diameter 6 mm, mean 2 stents per patient) were placed with average length of stented segment being 23.8 cm. Four patients had stents placed through ipsilateral popliteal artery approach with rest placed through femoral artery approach. Significant complications of the procedure included distal embolization (n=3) successfully managed with thrombolysis and popliteal arteriovenous fistula in one patient undergoing recanalization through popliteal approach, managed with covered stent placement. No procedure related mortality occurred during thirty-day follow-up period. All were followed up over an average duration of twelve months post-procedure. Three patients died due to associated medical conditions during this period. The following amputations were done on follow-up (three toe amputations, five forefoot amputations, three below-knee amputations, two above-knee amputations). The overall limb salvage rate was 80%. CONCLUSION: Our study shows beneficial result of SFA/PPA stent placement in diabetic occlusions with significant concomitant infrapopliteal disease.

Endovenous laser therapy in the treatment of lower-limb venous ulcers.

PURPOSE: To assess the efficacy of endovenous laser therapy (EVLT) in the treatment of lower-limb venous ulcers secondary to venous reflux. MATERIALS AND METHODS: Forty-four of 139 patients referred for EVLT from January 2004 to August 2007 had nonhealing venous ulcers. Preprocedural duplex ultrasound (US) was performed to document saphenous venous reflux secondary to saphenofemoral/saphenopopliteal junction incompetence, deep venous insufficiency, and deep vein thrombosis. Follow-up intervals were within 1 week, monthly until ulcer healing, and every 6 months thereafter. Mean follow-up period was 35.8 months (range, 8.1-59.3 months). RESULTS: Mean great saphenous vein (GSV) diameter and length treated were 9.9 mm (range, 5.5-16.0 mm) and 36.7 cm (range, 20.0-60.0 cm). Mean laser energy used was 3,292 J (range, 1,392-4,971 J). Mean energy deposited per centimeter of vein was 93.6 J/cm (range, 45.2-182.0 J/cm). Mean laser time was 232 seconds (range, 99-347 sec). Fifteen patients with follow-up duplex US had no GSV flow at 6 months, with nonvisualization indicating complete obliteration. Ulcer healing occurred as early as 1 week after the procedure in some patients. Cumulative healing rates at 1, 3, 6, and 12 months were 82.1%, 92.5%, 92.5%, and 97.4%, respectively. No ulcer had recurred at 1 year, but ulcers recurred in five patients at 14, 14, 23, 35, and 52 months after EVLT, respectively. One patient with a nonhealing ulcer 2 years after treatment developed well differentiated squamous cell carcinoma. CONCLUSIONS: Ulcer epithelization occurred with continued GSV occlusion and loss of flow. Most ulcers healed within 3 months with no recurrence at 1 year. Nonhealing ulcers should undergo biopsy to exclude malignant transformation.

Endovascular treatment of gastroduodenal artery aneurysm.

Gastroduodenal artery aneurysms are rare. Common causes include blunt trauma, pancreatitis, infection, autoimmune disorders, vascular intervention and surgery. We report 2 patients with gastroduodenal artery aneurysms, the first being an idiopathic true aneurysm and the next, a pseudoaneurysm resulting from pancreatitis. Diagnoses were made by computed tomography scans with successful embolization of both patients. Treatment of gastroduodenal artery aneurysms includes surgery, endovascular techniques or observation. Embolization is a feasible option for gastroduodenal artery aneurysms and pseudoaneurysms.

Extra-anatomic revascularization and aortic exclusion for mycotic aneurysms of the infrarenal aorta and iliac arteries in an Asian population.

OBJECTIVES: To study the clinical presentation, management and eventual outcome of patients with mycotic abdominal aortic aneurysms managed with aortic exclusion and extra-anatomic reconstruction. DESIGN: A retrospective chart review of 18 cases treated at a single institution. METHODS: Medical records of 18 patients admitted to our institution from October 1997 to July 2006 with a diagnosis of mycotic abdominal aortic aneurysms were reviewed. In all cases, the diagnosis was confirmed by abdominal computed tomography and empirical parenteral antibiotics were administered. Seventeen patients had surgical debridement, aneurysm exclusion, and extra-anatomic reconstruction. The antibiotics were continued in the postoperative period for 6 weeks. RESULTS: Immunosuppression was present in 72%, with diabetes mellitus present in 56%. Salmonella sp was the causative organism in 72% of cases. Most patients presented late, with a 67% incidence of contained rupture. Seventy-two percent needed early or emergency surgery with less than 1 week of preoperative antibiotics. Disease-specific mortality was 39% (7/18). There was 1 late death during the mean follow-up period of 34 +/- 26 months. One patient with an infrarenal aneurysm arising relatively close (neck, 2 cm) to the renal arteries died on table when proximal ligatures cut through the friable aortic wall, resulting in uncontrollable exsanguination. One third of patients on long-term graft surveillance developed mild to moderate stenosis at the anastomotic site. CONCLUSIONS: Empirical antibiotics must be started early, aiming to achieve 1 week of antibiotics prior to surgery. In the Asian population, 3 characteristics are apparent: (1) most patients are immunocompromised; (2) patients present late in the course of disease; and (3) Salmonella is usually responsible. Extra-anatomic bypass may provide a safe option for revascularization of mycotic aneurysms of the iliac arteries and infrarenal aorta.

Arteriovenous fistula aneurysm--plicate, not ligate.

INTRODUCTION: Arteriovenous fistula (AVF) created for haemodialysis can be complicated by aneurysm formation. CLINICAL PICTURE: Ligation of the fistula is often required to prevent aneurysmal rupture and the life-threatening haemorrhage that ensues. Other methods of treatment involve using foreign bodies like mesh and grafts. TREATMENT: We describe a new method in the treatment of this condition--plication. It involves plicating the excess free wall of the aneurysm with sutures and does not require resection or anastomosis. OUTCOME: Early results show that this method shrinks the aneurysm size and reduces the risk of haemorrhage. CONCLUSION: The AVF can continue to be used and the patient is spared the agony of having to go through the entire cycle of creating a new vascular access site.

A case report of endovascular stenting in Salmonella mycotic aneurysm: a successful procedure in an immunocompromised patient.

INTRODUCTION: Mycotic aneurysms are associated with high mortality rates and are managed in the local setting with extra-anatomical bypass followed by ligation, exclusion and debridement of the aneurysm. This is the first case of successful endovascular stenting in an immunocompromised patient with Salmonella mycotic aneurysm. CLINICAL PICTURE: A middle-aged man who was HIV positive had Salmonella septicaemia. He developed abdominal pain 5 days after admission and a computed tomography (CT) scan of the abdomen revealed infrarenal aortitis. He developed a mycotic aneurysm 3 weeks later. TREATMENT: He opted for endovascular stenting and after prolonged antibiotic therapy and negative blood cultures, he underwent the procedure using a Talent stent, with an iliac extension. OUTCOME: He was discharged 1 week after stenting and maintained on oral bactrim based on sensitivity. At 1-year follow-up, he remains well symptomatically and CT scan showed no endoleak or collection. CONCLUSION: Endovascular stenting, though a fairly new procedure, can be successfully deployed even in a mycotic aneurysm in the right setting.

Diagnosis and surgical management of popliteal artery entrapment syndrome.

BACKGROUND: The purpose of the present study was to report the authors' experience of surgically treating eight limbs in six patients for popliteal artery entrapment syndrome (PAES), over a 10-year period. METHODS: From 1995 to 2004, six patients (eight limbs) underwent surgery for PAES at a single institution. The patients' data were collected retrospectively from the case records and operative notes. RESULTS: There were six patients with a mean age of 34 years (range, 27-38 years) at diagnosis and five of them were male. Two patients were found to have bilateral involvement. Both patients had symptoms involving both limbs and underwent bilateral surgery. Intermittent claudication was the most frequent presenting symptom (seven of eight limbs). All the patients had Delaney's type III PAES. Popliteal artery release was performed in all eight limbs and this was combined with a vein patch or a reversed long saphenous vein bypass graft in four limbs because the arteries in these four limbs were diseased or occluded. At a median follow up of 15 months (range, 40 days-9 years), five (seven limbs) of the six patients (eight limbs) were cured of their symptoms. One patient who presented late with rest pain and dusky toes underwent popliteal artery release, endarterectomy and a vein patch repair for an occluded popliteal artery. However, her limb could not be salvaged and her affected limb had to be amputated. CONCLUSION: Popliteal artery entrapment syndrome is a rare but important cause of peripheral vascular insufficiency especially in young patients. Early diagnosis and surgical intervention is imperative for good operative outcome and to prevent limb loss.

Severe acute respiratory syndrome in surgical patients: a diagnostic dilemma.

BACKGROUND: The diagnosis of severe acute respiratory syndrome (SARS) in surgical patients can potentially be missed based on current World Health Organization (WHO) case definitions. METHOD: We report a retrospective case series of 10 surgical inpatients diagnosed with SARS following an outbreak in the surgical wards. Patients were included if they fulfilled the WHO case definition of probable SARS, had an active surgical problem and were admitted to the surgical wards during the outbreak period. Clinical histories, laboratory investigations and radiological findings were reviewed and analyzed. RESULTS: The mean age of the cohort was 57.6 years (range: 38-78 years). Nine patients had concomitant medical conditions. Three patients were in the early postoperative period, while the remaining seven were admitted for surgical related infections. All patients presented with fever, but only eight had accompanying respiratory symptoms. Lymphopenia and raised lactate dehydrogenase (LDH) was seen in seven patients. Eight patients had positive bacterial cultures. The primary abnormality on chest radiograph was air-space opacification. Rapid progression of radiological changes was seen in seven patients. Mortality rate for our cohort is 20%. CONCLUSION: The diagnosis of SARS in surgical patients differs from that previously described in normal patients. An apparent cause of fever and positive blood cultures cannot exclude a diagnosis of SARS. The current WHO case definition could result in delayed or even missed diagnosis. Early isolation of febrile patients with a positive contact history must be undertaken, even in the face of another identifiable cause.

Polyurethane grafts: a viable alternative for dialysis arteriovenous access?

Polyurethane grafts, promoted for their self-sealing properties and low complication rates, were recently introduced for hemodialysis access. We review our experience with this graft material to determine its complication and patency rates. Between January 1995 and December 1999, 118 patients, 75 female and 43 male, with a mean age of 51 years, had a total of 163 polyurethane arteriovenous grafts inserted. The grafts were mostly 6 mm in diameter (69.3%), placed in a loop configuration (91.4%) in the forearm (49.7%). The median follow-up period was 12 months. The grafts were first cannulated for hemodialysis at a median time of 19 days after implantation, with 12% used within 3 days. Thrombosis and infection were the most common complications at rates of 32.7% and 30.0%, respectively. Infection was the most common cause of graft loss (61.5%). These complications were amenable to salvage intervention. The 1-year primary and secondary patency rates were 73% and 86%, respectively; the 3-year secondary patency rate, 72%. The 1-year serviceability rate was 64%. With satisfactory patency rates and the advantage of its self-sealing properties permitting early cannulation, polyurethane grafts provide a viable alternative for hemodialysis access. Early recognition and appropriate management of complications can prolong graft survival.

Utility of portable continuous-wave Doppler examination in screening for postoperative deep vein thrombosis.

BACKGROUND: Early and accurate diagnosis of post-surgical deep vein thrombosis (DVT) can be difficult and time-consuming, even with duplex ultrasonography. Portable continuous-wave Doppler ultrasonography may be useful in screening patients for postoperative DVT. Further confirmation of Doppler-positive cases by duplex ultrasound might then be more cost-effective. METHODS: All major post-surgical patients from the departments of general surgery, orthopaedic surgery and colorectal surgery were screened on the third postoperative day for DVT by assessing the quality of the flow signal ("whoosh") obtained by placing the probe over the femoral vein and subsequently over the popliteal vein, both with a distal squeeze, as well as assessment of phasic flow with respiration. An absent or attenuated "whoosh" was judged to be suspicious for DVT and required formal duplex ultrasonography. The first 800 consecutive patients were studied to determine the sensitivity, specificity and accuracy of portable Doppler ultrasonography for DVT screening. RESULTS: Twenty-four cases of DVT were diagnosed, comprising seven cases in the proximal veins and 17 cases in the calf veins. The sensitivity of Doppler ultrasonography was 12.5% and the specificity was 96.8%. The positive and negative predictive values were 10.7% and 97.3%, respectively. CONCLUSIONS: Portable Doppler ultrasonography does not have adequate accuracy to be used as a quick screening tool for DVT.