Hepatic venous outflow obstruction in living donor liver transplantation: balloon angioplasty or stent placement?

Background

The incidence of hepatic venous outflow obstruction (HVOO) has been reported to be 5%-13% when a partial graft is used for orthotopic liver transplantation (OLT). HVOO leads to graft congestion, portal hypertension, and finally cirrhosis, which jeopardizes both graft and recipient survivals. In this study, we sought to identify perioperative factors influencing HVOO and to investigate conditions that require stent placement.

Patients and Methods

From February 1994 to December 2010, we performed 40 living donor liver transplantations (LDLT). HVOO occurred in 5 cases (12.5%), all of which were left lobe grafts. Because HVOO was not observed in patients with body weight (BW) <30 kg, we investigated the other 28 cases with BW >30 kg.

Results

There was no difference from unaffected subjects except for cold ischemic time (CIT), which was significantly longer: 86.2 ± 10.4 minutes vs 46.0 ± 4.8 minutes (P = .001). Balloon angioplasty, which was selected as the initial treatment for all stricture patients, improved 2 patients after 1 and 5 treatments, respectively, but 3 subjects underwent repeated HVOO, finally being treated with self-expandable metallic stents at 9, 6, and 10 years after LDLT, respectively. All patients finally resolved their strictures.

Conclusion

HVOO reflects intimal hyperplasia and fibrosis at the anastomotic sites or compression and twisting of the anastomosis caused by graft regeneration. In addition, progression of chronic rejection and fibrosis are possibly responsible for late-onset HVOO. Longer CIT possibly reflects difficulties in the venoplasty before anastomosis. No bleeding or thrombosis complications were observed during dilatation among our cases. The selection of the stent size for each case and careful stent deployment are important to prevent complications. Stent placement should be considered in patients with chronic rejection who are refractory to several balloon angioplasties with early-onset or late-onset HVOO.     

Does thigh compression improve venous hemodynamics in chronic venous insufficiency?

OBJECTIVE: The aim of this study was to investigate the hemodynamic effects of thigh compression in patients with deep venous incompetence. PATIENTS AND METHODS: This diagnostic test study was set in a municipal general hospital. Twelve patients with venous leg ulcers (CEAP classification, C6 Es Ad Pr; four men and eight women), with a mean age of 56.5 +/- 16.8 years, with popliteal venous reflux of more than 1 second detected with duplex scan, underwent investigation with the following methods: 1, the pressure exerted under thigh-length compression stockings class II and short-stretch adhesive compression bandages was measured with an MST tester (Salzmann, Switzerland) and a CCS 1000 device (Juzo, Germany), respectively; 2, the great saphenous vein and the femoral vein on the thigh were compressed with a pneumatic cuff (0, 20, 40, and 60 mm Hg) containing a window through which the diameters of these veins could be measured with duplex ultrasonography; and 3, with the same thigh-cuff occlusion procedure, the venous filling index (VFI) for each experiment was measured with air plethysmography. These values reflected the presence and extent of venous reflux in each experiment depending on the degree of venous narrowing. RESULTS: The mean pressure of a class II compression stocking was about 15 mm Hg at the thigh level, and adhesive bandages achieved a pressure of more than 40 mm Hg in the same location. A statistically significant reduction of the diameters of the great saphenous vein and the femoral vein could be obtained only when the cuff pressure on the thigh was equal to or higher than 40 mm Hg (P <.001). A reduction of the venous reflux (VFI) was achieved only with a thigh pressure of 60 mm Hg (P <.001). No significant reduction was seen of VFI with a thigh pressure in the range of the class II stockings. Previous investigations have shown that, in patients with deep venous incompetence, a pressure cuff on the thigh with 60 to 80 mm Hg is able to reduce ambulatory venous hypertension. CONCLUSION: Thigh compression as exerted with class II thigh-length compression stockings is not able to significantly reduce venous diameter or venous reflux. However, with a pressure of 40 to 60 mm Hg on the thigh that can be achieved with strongly applied short-stretch bandages, considerable hemodynamic improvement, including reduced venous reflux, can be obtained in patients with severe stages of chronic venous insufficiency from deep vein incompetence. The practical value of these preliminary findings should be investigated with further clinical trials.     

Prophylaxis against venous thromboembolism in orthopedic surgery

Venous thromboembolism (VTE), which is manifested as deep vein thrombosis (DVT) and pulmonary embolism (PE), represents a significant cause of death, disability, and discomfort. They are frequent complications of various surgical procedures. The aging population and the survival of more severely injured patients may suggest an increasing risk of thromboembolism in the trauma patients. Expanded understanding of the population at risk challenges physicians to carefully examine risk factors for VTE to identify high-risk patients who can benefit from prophylaxis. An accurate knowledge of evidence-based risk factors is important in predicting and preventing postoperative DVT, and can be incorporated into a decision support system for appropriate thromboprophylaxis use. Standard use of DVT prophylaxis in a high-risk trauma population leads to a low incidence of DVT. The incidence of VTE is common in Asia. The evaluation includes laboratory tests, Doppler test and phlebography. Screening Doppler sonography should be performed for surveillance on all critically injured patients to identify DVT. D-Dimer is a useful marker to monitor prophylaxis in trauma surgery patients. The optimal time to start prophylaxis is between 2 hours before and 10 hours after surgery, but the risk of PE continues for several weeks. Thromboprophylaxis includes graduated compression stockings and anticoagulants for prophylaxis. Anticoagulants include Warfarin, which belongs to Vitamin K antagonists, unfractionated heparin, low molecular weight heparins, factor Xa indirect inhibitor Fondaparinux, and the oral IIa inhibitor Melagatran and ximelagatran. Recombinant human soluble thrombomodulin is a new and highly effective antithrombotic agent. Prophylactic placement of vena caval filters in selected trauma patients may decrease the incidence of PE. The indications for prophylactic inferior vena cava filter insertion include prolonged immobilization with multiple injuries, closed head injury, pelvic fracture, spine fracture, multiple long bone fracture, and attending discretion. Multiple-trauma patients are at increased risk for DVT but are also at increased risk of bleeding, and the use of heparin may be contraindicated. Serial compression devices (SCDs) are an alternative for DVT prophylaxis. Compression devices provide adequate DVT prophylaxis with a low failure rate and no device-related complications. Immobilization is one of important reasons of VTE. The ambulant patient is far less Ukely to develop complications of inactivity, not only venous thrombosis, but also contractures, decubitus ulcers, or osteoporosis ( with its associated fatigue fractures), as well as bowel or bladder complications.     

Microvascular changes in chronic venous insufficiency—a review

Chronic venous insufficiency is the result of an impairment of the main venous conduits, causing microvascular changes. The driving force responsible for the alterations in the microcirculation is probably the intermittently raised pressure propagated from the deep system into the capillaries. The capillaries are dilated, elongated and tortuous and their endothelium is injured (irregular luminal surface, increased cytopempsis, dilated interendothelial spaces). Through the latter an increased extravasation can be observed, leading to an enlarged pericapillary space, oedema in the interstitial tissue and to the clinical finding of swelling. Haemoglobin from extravasated erythrocytes and erythrocyte fragments in the pericapillary space is degraded to haemosiderin which is responsible for hyperpigmentation. Microthrombosis in the capillaries causes microinfarction and micronecrosis. Skin areas with severe microangiopathy have reduced numbers of perfused nutritional capillaries and are characterized by a low transcutaneous (tc) po₂. The increased blood flow in the deeper skin layers does not contribute to nutrition of the superficial skin layers. The microvascular ischaemia is patchy and appears to be the main factor determining trophic changes and venous ulceration. The process of microinfarction and micronecrosis is followed by the formation of a granulation tissue, proliferation of capillaries and fibroblasts and finally wound healing by formation of scar tissue destroying the microlymphatic network. Clinically this process leads to lipodermatosclerosis, atrophy and in its most extreme form to ulceration where the compensating mechanisms are no longer able to repair the damage.     

Does severe venous insufficiency have a different etiology in the morbidly obese? Is it venous?

OBJECTIVE: Chronic venous insufficiency (CVI) is the most common cause of leg ulcers. Patients with morbid obesity are remarkable for particularly recalcitrant ulcers. Because obesity is not specifically incorporated in CEAP or other venous scoring systems, we sought to characterize this group of patients more completely. METHODS: Patients with severe CVI (CEAP clinical class, 4, 5, and 6), and class III obesity (body mass index [BMI], >40) were reviewed. Findings from clinical and duplex ultrasound scan (DU) examinations were compared with the CEAP classification, its adjunctive venous clinical severity score, and sensory thresholds. RESULTS: A review of clinic records identified 20 ambulatory patients with a mean age of 62 years, a mean BMI of 52, and a mean weight of 164 kg (361 lbs); all but one had bilateral symptoms. No evidence of venous insufficiency was detected with DU in 24 of the 39 limbs. Although some valvular incompetence was detected with DU in 15 of 39 limbs, these abnormalities were widely dispersed between 28 sites; eight limbs had findings at only one site. Ulceration (mean area, 29 cm(2)) was present in 25 limbs and necessitated 7 months for healing; 13 (52%) recurred at least once during a mean observation period of 36 months. The mean sensory threshold of 5.21 exceeded current risk thresholds used in diabetic screening programs. The distribution of CEAP clinical class was C4 (n = 14), C5 (n = 14), and C6 (n = 11). Increasing CEAP class correlated with an increased mean BMI of 47, 52, and 56, respectively (P <.01). CEAP also correlated with a rising mean venous clinical severity score of 10, 11, and 15, respectively (P <.05). CONCLUSION: Patients with class III obesity had severe limb symptoms, typical of CVI, but approximately two thirds of the limbs had no anatomic evidence of venous disease. The association of increasing limb symptoms with increasing obesity suggested that the obesity itself contributes to the morbidity.     

Surgical treatment of venous malformations in Klippel-Trénaunay syndrome

PURPOSE: Klippel-Trénaunay syndrome (KTS) is a complex congenital anomaly, characterized by varicosities and venous malformations (VMs) of one or more limbs, port-wine stains, and soft tissue and bone hypertrophy. Venous drainage is frequently abnormal because of embryonic veins, agenesis, hypoplasia, valvular incompetence, or aneurysms of deep veins. We previously reported on the surgical management of KTS. In this article, we update our experience. METHODS: Twenty patients with KTS underwent surgical treatment for VMs between July 1, 1987, and January 1, 2000. This group represented 6.9% of 290 patients with KTS who were seen at our institution during this 12.5-year study period. Surgical indications, venous anatomy (determined with duplex scan, contrast phlebography, magnetic resonance imaging or magnetic resonance phlebography), operative procedures, and complications were reviewed, and outcomes were recorded. RESULTS: Twelve male and eight female patients (mean age, 23.4 years; range, 7.7-40.6 years) underwent 30 vascular surgical procedures in 21 lower limbs. All 20 patients (100%) had varicose veins or VMs, 13 (65%) had port-wine stains, and 18 (90%) had limb hypertrophy. Pain was the most common complaint, which was present in 16 patients (80%), followed by swelling in 15 (75%), bleeding in 8 (40%), and superficial thrombophlebitis and cellulitis in 3 (15%). Imaging confirmed patent deep veins in 18 patients, hypoplastic femoral vein in 1, and entrapped popliteal veins bilaterally in 1. Four patients (20%) had large persistent sciatic veins (PSVs). The CEAP clinical classification was C-3 for 17 patients (85%), C-4 for 1 patient (5%), and C-6 for 2 patients (10%). Stripping of large lateral veins, avulsion, and excision of varicosities or VMs were performed on all limbs. Three patients required staged resections. The release of entrapped popliteal veins was performed in both limbs of one patient; another underwent a popliteal-saphenous bypass graft. One patient underwent excision of a PSV. Open and endoscopic perforator vein ligation was performed in one patient each. Two patients (12%) had hematomas that required evacuation. No patients had caval filter placement; none had postoperative deep venous thrombosis or pulmonary embolus. The mean follow-up was 63.6 months (range, 0-138 months). All patients reported initial improvement, but some varicosities recurred in 10 patients (50%), an ulcer did not heal in one, and a new ulcer developed in one, 8 years after surgery. Three patients underwent reoperation for recurrent varicosities. Follow-up CEAP scores were C-2 in 10 patients (50%), C-3 in 6 patients (30%), C-4 and C-5 in 1 patient each (5%), and C-6 in 2 patients (10%). Clinical scores improved from 4.3 +/- 2.2 to 3.1 +/- 2.3. (P =.03). CONCLUSIONS: The management of patients with KTS continues to be primarily nonoperative, but those patients with patent deep veins can be considered for excision of symptomatic varicose veins and VMs. Although the recurrence rate is high, clinical improvement is significant, and reoperations can be performed if needed. Occasionally, deep vein reconstruction, excision of PSVs, or subfascial endoscopic perforator surgery is indicated. Because KTS is rare, patients should receive multidisciplinary care in qualified vascular centers.     

Is upper extremity deep venous thrombosis underdiagnosed in trauma patients?

It has been suggested that upper extremity deep venous thrombosis (UEDVT) is as common and dangerous as lower extremity deep venous thrombosis. Pulmonary embolism (PE) is often found with no evidence of associated lower extremity deep venous thrombosis and could have originated from UEDVT. Routine screening is well accepted for lower extremity deep venous thrombosis but not for UEDVT. We hypothesized that UEDVT in trauma is frequent but undetected; therefore, routine screening of trauma patients at risk will increase the UEDVT rate and decrease the PE rate due to early diagnosis and treatment. We evaluated the incidence of UEDVT and PE over 6 months before (Group BEFORE) and 6 months after (Group AFTER) implementing a policy of screening patients at high risk for deep venous thrombosis with Duplex ultrasonography. Group BEFORE was evaluated retrospectively and group AFTER prospectively. There were 1110 BEFORE and 911 AFTER patients. The two groups were similar. Of the AFTER patients, 86 met predetermined screening criteria and were evaluated routinely by a total of 130 Duplex exams. One patient in each group developed UEDVT (0.09% vs. 0.11%, P = 1.00). The brachial vein was involved in both patients. Six BEFORE (0.54%) and 1 AFTER (0.11%) patients developed PE (P = 0.137). The single AFTER patient with PE was not screened for UEDVT because he had no high-risk criteria. UEDVT is an uncommon event with unclear significance in trauma. Aggressive screening did not result in a higher rate of UEDVT diagnosis, nor an opportunity to prevent PE.     

Do multiple venous anastomoses reduce risk of thrombosis in free-flap transfer? Efficacy of dual anastomoses of separate venous systems

Whether or not multiple venous anastomoses reduce the risk of free-flap failure is a subject of controversy. We report here, for the first time, on the importance of selecting 2 separate venous systems of the flap for dual anastomoses. The efficacy of multiple anastomoses was verified through a retrospective review of 310 cases of the free radial forearm flap transfer. Dual anastomoses of separate venous systems (the superficial and the deep) showed a lower incidence of venous insufficiency than single anastomosis did (0.7% versus 7.5%; P < 0.05). On the other hand, dual anastomoses of a sole venous system showed no significant difference in the incidence of venous insufficiency compared with single anastomosis (11.5% versus 7.5%; P = 0.48). Our results suggest that dual venous anastomoses of separate venous systems is conducive to reduced risk of flap failure and affords protection against venous catastrophe through a self-compensating mechanism that obviates thrombosis of either anastomosis.     

Stent or bypass? Treatment results in benign central venous obstruction

PURPOSE: Surgical treatment of central venous obstruction is difficult and sometimes hazardous, but not always successful. Sufficient palliation of malign stenoses can often be achieved by stent implantation. Thus it seems necessary to define the relative value of stenting in comparison to surgical reconstruction for the treatment of benign obstructions, with special respect to the long-term results. METHODS: Between 1990 and 1999, 64 central venous stents were implanted. Mediastinal vein obstructions in 23 hemodialysis patients were treated with a total of 35 stents. 29 iliofemoral stents were implanted following operative or conservative treatment of 21 venous thromboses. During the same time period, only 6 surgical bypasses were performed (all in hemodialysis patients). All patients were followed-up prospectively. Patency rates were calculated according to the life table-method. RESULTS: Following stent implantation one asymptomatic pulmonary stent embolism (2.3%) and three stent misplacements (6.8%) were documented. Two of the latter were successfully treated with another stent. In the surgical group, one patient died at eight weeks due to late complications of a cephalosporine-associated Lyell syndrome. One to five year patency rates were not significantly different among the three groups. CONCLUSION: For benign central venous stenoses in hemodialysis patients and following iliofemoral venous thrombosis, stent implantation can be recommended as a simple, safe, and durable means to restore patency. Still there is a role for surgery in severely symptomatic central venous occlusions when stent implantation is impossible or has failed.     

Central venous oxygen saturation monitoring: role in adult donor care?

Monitoring oxygen saturation of blood drawn from a catheter placed within the superior vena cava (Scvo2) has recently been promoted as a substitute for evaluating oxygen saturation of mixed venous blood drawn from the pulmonary artery (Svo2). The Svo2 reflects the balance between oxygen delivery and oxygen consumption throughout the body and, among critically ill patients, may be helpful for assessing resuscitation, cardiac function, or oxygen homeostasis end points. Use of Scvo2 instead has been promoted because of its easier access and recent use during resuscitation of patients with severe infections. Although data from healthy subjects and critically ill patients are available, no study has been done among organ donors to evaluate customary values for either Scvo2 or Svo2 or how well the values correspond. After loss of oxygen consumption in the brain following brain death, the customary values for these variables may be different from values in other groups of patients. Therefore, until donor-specific normative values for these important parameters are identified, we do not recommend that Scvo2 be used to evaluate the balance between donor oxygen consumption and delivery or as a variable to guide treatment.     

Reducing central venous catheters in chronic hemodialysis—a commitment to arteriovenous fistula creation in children

Background

An internal permanent vascular access [arteriovenous fistula (AVF) or arteriovenous graft (AVG)] is preferred over central venous catheters (CVC) for chronic hemodialysis. However, CVC remain the most commonly used access in children. The objective of this study was to evaluate our experience with AVF.

Methods

We conducted a retrospective chart review of children aged 1–18 years on chronic hemodialysis from 2001 to 2012. Patients were divided into three time periods: 2001–2005, 2006–2009 and 2010–2012. A systematic approach to AVF placement was introduced in our department in 2006 which resulted in a greater number of AVF being placed and used, but the access failure rate was still higher than desired. In 2010, a more experienced vascular surgeon was contacted to perform AVF surgery in our most difficult AVF candidates.

Results

Sixty-five AVF were created in 55 patients (67.3 % male). The median age of the patients was 14 (3–18) years. Forty-one (63.1 %) AVF were used successfully, and this number increased from 52.6 to 57.6 to 92.3 % over the three time periods, respectively. Over time, AVF use rates increased and CVC use decreased. By 2012 only 7.7 % of our patients were using a CVC. The primary patency rate was 42.9 % at 1 year; secondary patency rates were 100 and 93.8 % at 1 and 2 years, respectively. Infection and hospitalization rates were higher for CVC than for AVF [0.8 vs. 0.1 infections per access-year (p?p?Conclusions With a dedicated approach and vascular access team it is possible to decrease CVC and increase AVF use in children on hemodialysis. In our study, increased AVF use resulted in decreased access-related infection and hospitalization rates.     

Central venous catheter infection-induced Henoch-Schönlein purpura in a patient on hemodialysis

A 69-year-old man, who had been dialyzed using a permanent central venous catheter for 2 years, presented with Henoch-Schönlein purpura and positive perinuclear anti-neutrophil cytoplasmic antibody (p-ANCA). He was diagnosed with catheter-related infection by Staphylococcus aureus. After administration of antibiotic and steroid therapy, purpura disappeared and p-ANCA gradually became negative. This case supports the conclusion that infection can be pathogenesis of the vasculitis, including ANCA-positive HSP. Additionally, impregnation of catheters with antibiotics can be an effective treatment for catheter infections.     

How useful is ultrasound guidance for internal jugular venous access in children?

Purpose

The aim of this study was to determine whether US reduces number of puncture attempts, procedure time, and complication rate during IJV access in children.

Does a lidocaine patch reduce the pain at venous cannulation in adults?

In this study we evaluated whether a lidocaine patch reduces the pain relating to a venous cannulation in adults. The patch is consisted of the base containing 50% lidocaine on a thin polyester membrane. Its surface area is 15 cm2. Twenty-six adult patients scheduled for elective surgery (11 males and 15 females) were randomly divided into two groups according to application periods: Group A for 15 min and Group B for 30 min. Either the dorsal part of the hand or the radial side of the wrist was chosen and covered with the patch. Pain assessment was made by patients using a 0-100 point visual analog scale (VAS). In 7 patients of Group A, plasma lidocaine levels were measured 15 min after application by homogeneous enzyme immunoassay. The levels were further measured 30 and 60 min after application in 3 of those patients. The mean VAS score was 28.4 +/- 13.1 (mean +/- SD) for Group A and 51.8 +/- 15.9 for Group B, and the difference was statistically significant (P < 0.05). Plasma lidocaine levels were always below 0.2 microg.ml(-1). The results indicate that the skin was partially anesthetized by the lidocaine patch. A lidocaine patch may be useful and safely applicable for venous cannulation in adult patients.