[Hyperinsulinemia as a consequence of systemic venous drainage in patients with pancreas transplantation]

To evaluate the metabolic consequences of pancreatic transplantation with systemic venous drainage on beta cell function, we examined insulin and C-peptide responses to arginine and secretin in type I diabetic recipients of pancreas transplantation (n = 16), and normal controls (n = 28). Basal insulin levels were 24 +/- 3 microU/l in pancreas recipients, and 7 +/- 1 microU/l in controls (p less than 0.001). Stimulated insulin levels following arginine (MANOVA, p less than 0.001), and secretin (MANOVA, p less than 0.001) were 1.5 to 3 fold elevated compared to controls. In contrast, integrated C-peptide responses following stimulation with arginine or secretin did not differ significantly between the two groups. We conclude that recipients of pancreas allografts with systemic venous drainage have elevated basal and stimulated insulin levels and that these alterations are primarily due to alterations of first pass hepatic insulin clearance although insulin resistance secondary to immunosuppressive therapy (including prednisone) may also play a contributing role. To avoid hyperinsulinemia and its possible long term adverse consequences, transplantation of pancreas allografts in sites with portal rather than systemic venous drainage may be preferable.

Systemic venous drainage of pancreas allografts as independent cause of hyperinsulinemia in type I diabetic recipients

To evaluate the metabolic consequences of pancreas transplantation with systemic venous drainage on beta-cell function, we examined insulin and C-peptide responses to glucose and arginine in type I (insulin-dependent) diabetic pancreas recipients (n = 30), nondiabetic kidney recipients (n = 8), and nondiabetic control subjects (n = 28). Basal insulin levels were 66 +/- 5 pM in control subjects, 204 +/- 18 pM in pancreas recipients (P less than 0.0001 vs. control), and 77 +/- 17 pM in kidney recipients. Acute insulin responses to glucose were 416 +/- 44 pM in control subjects, 763 +/- 91 pM in pancreas recipients (P less than 0.01 vs. control), and 589 +/- 113 pM in kidney recipients (NS vs. control). Basal and stimulated insulin levels in two pancreas recipients with portal venous drainage were normal. Integrated acute C-peptide responses were not statistically different (25.3 +/- 4.3 nM/min in pancreas recipients, 34.2 +/- 5.5 nM/min in kidney recipients, and 23.7 +/- 2.1 nM/min in control subjects). Similar insulin and C-peptide results were obtained with arginine stimulation, and both basal and glucose-stimulated insulin-C-peptide ratios in pancreas recipients were significantly greater than in control subjects. We conclude that recipients of pancreas allografts with systemic venous drainage have elevated basal and stimulated insulin levels and that these alterations are primarily due to alterations of first-pass hepatic insulin clearance, although insulin resistance secondary to immunosuppressive therapy (including prednisone) probably plays a contributing role. To avoid hyperinsulinemia and its possible long-term adverse consequences, transplantation of pancreas allografts into sites with portal rather than systemic venous drainage should be considered.

Experimental ovine model of primary venous valve incompetence: a pilot study

PURPOSE: To compare two techniques used to create a larger animal model of venous valve incompetence. MATERIALS AND METHODS: To achieve vein dilatation as the primary cause of valve incompetence, common carotid jugular vein (JV) fistulas were created and optional filters were placed into the JV of sheep. Altogether, nine inferior vena cava filters were placed in three sheep in two stages. Six filters were placed caudal to the most caudal JV valve in three sheep and removed 6 weeks later. Then, three filters were placed across the most caudal valve in two sheep with competent valves and removed 3 weeks later. A common carotid artery-JV fistula was created in three sheep and followed-up for 1-3 weeks. Ascending and descending venograms were obtained to determine the JV sizes and function of their valves. The JVs removed at necropsy were studied with venoscopy. RESULTS: Only one of the six JVs with filters caudal to the most caudal valve had incompetent valves after filter removal at 6 weeks. In addition, only one of three JVs with the filter across the valve had incompetent valves after filter removal at 3 weeks. At 1-3-week follow-up of the group with common carotid artery-JV fistula, all three JVs had incompetent valves in the cephalad vein portion, but only one JV had an incompetent valve in its caudal portion. At venoscopy, the incompetent valves showed various degrees of damage ranging from shortening to the destruction of valve leaflets. CONCLUSION: Dilation of the valve annulus with a removable vena cava filter failed to produce valve incompetence. The promising results with the common carotid artery-JV fistula justify further detailed research.

Percutaneous autologous venous valve transplantation: short-term feasibility study in an ovine model

BACKGROUND: Limited experience with bioprosthetic venous valve percutaneously inserted into femoral veins in 15 patients has been promising in short-term results only to show disappointing long-term results. Percutaneous autogenous venous valve (PAVV) transplantation was explored in an ovine model as a possible alternative treatment. METHODS: PAVV consisted of a vein segment containing a valve that was attached to a stent template. The stent templates (n = 9) were designed and hand made in our research laboratory. They consist of two stainless steel square stents 13 or 15 mm in diameter to fit the ovine jugular veins (JV), which ranges from 10 to 15 mm in diameter. A valve-containing segment of JV was harvested and attached with sutures and barbs inside the stent template (n = 9). The valve devices were then manually folded and front loaded inside the 4 cm chamber of the 13F delivery sheath and delivered into the contralateral JV by femoral vein approach. Transplanted PAVVs were studied by immediate and 3 months venograms. Animals were euthanized at 3 months, and jugular veins harvested to perform angioscopic evaluations in vitro. RESULTS: PAVV transplantation was successful in all nine animals. Good valve function with no reflux was observed on immediate and 3 months venograms in eight valves. The transplanted maximal JV diameter ranged from 10.2 mm to 15.4 mm (mean 13.1 +/- 1.5 mm). Venoscopic examination revealed intact, flexible, nonthickened valve leaflets in eight specimens. One PAVV exhibited normal function of one leaflet only; the other cusp was accidentally cut during the transplantation procedure. All transplanted autologous valves were free of thrombus and incorporated into the vein wall of the host vessel. CONCLUSION: This study demonstrated that autogenous valve transplants remained patent and competent without long-term anticoagulation for up to 3 months. The percutaneous autogenous venous valve may provide in future minimally invasive treatment for patients with chronic deep venous insufficiency, but long-term studies need to be done to document its continued patency and function.

Orbital venous malformation: percutaneous treatment using an electrolytically detachable fibred coil

PURPOSE: To report the efficacy of percutaneous treatment of an orbital venous malformation with an electrolytically detachable fibred coil. METHODS: We report an instance of radiography-guided percutaneous treatment with an electrolytically detachable fibred coil in a 16-year-old boy with acute, spontaneous, painless proptosis on the left side, which progressed with time. RESULTS: Magnetic resonance imaging, angiography and orbitophlebography revealed a low-flow, intraorbital venous malformation. Percutaneous puncture and drainage were followed by a short remission. Following an acute recurrence, a single detachable fibred coil was deployed via a percutaneous approach under angiographic guidance. No radiological or clinical recurrences were observed over 4 years. CONCLUSIONS: Embolization of a deep orbital venous malformation with detachable fibred coils via a percutaneous approach can be highly effective, and may be considered before proceeding with open surgery.

Cardiomegaly in a premature neonate after venous umbilical catheterization

Umbilical venous catheters allow rapid central access in neonates, but may be associated with various complications. We present a case of a newborn with pericardial effusion following umbilical venous catheterization. An extremely low birth weight infant was intubated for respiratory distress syndrome and had umbilical venous and arterial lines in place. Massive cardiomegaly was noted on the subsequent chest X-ray. Echocardiography revealed a large pericardial effusion without signs of tamponade. After removing the catheter, the effusion gradually resolved. While pericardial effusion is a well-known complication of percutaneous long central lines, only a few case reports have documented sudden cardiovascular compromise associated with umbilical venous catheters. Pericardial effusion may be asymptomatic and should be suspected in infants with central catheters and progressive cardiomegaly. The prompt removal of catheters and, if signs of cardiac tamponade are present, emergency pericardiocentesis may prove to be life-saving.

Association of fatigue and psychological distress with quality of life in patients with a previous venous thromboembolic event

Health-related quality of life (QoL) has been associated with several social and medical conditions in patients with deep vein thrombosis (DVT) and pulmonary embolism (PE). To the best of our knowledge, there is no study investigating the relationship of QoL with psychological variables in this patient population. We assumed as a hypothesis an association between heightened levels of fatigue and psychological distress, as well as decreased QoL in patients with an objectively diagnosed venous thromboembolic event. Study participants were 205 consecutively enrolled out-patients (47.4 years, 54.6% men) with DVT and/or PE. Approximately 10 days before blood collection for thrombophilia work-up, QoL, fatigue, and psychological distress were assessed using the Short Form Health Survey (SF-12), the Multidimensional Fatigue Symptom Inventory Short Form (MFSI-SF) as well as the Hospitality Anxiety and Depression scale (HADS). After controlling for demographic and medical factors, fatigue (p < 0.01) but not psychological distress (p>0.05) was negatively associated with physical QoL, explaining 11.0% of the variance. Fatigue (p < 0.001) and psychological distress (p < 0.001) were significant predictors of mental QoL, explaining an additional 36.2% and 3.6% of the variance. Further analyses revealed that all subscales of the HADS (e.g. anxiety and depression) and of the MFSI-SF (e.g. general fatigue, physical fatigue, emotional fatigue, mental fatigue and vigor) were significant predictors of mental QoL. MFSI-SF subscales also predicted physical QoL. The findings suggest that fatigue and psychological distress substantially predict QoL in patients with a previous venous thromboembolic event above and beyond demographic factors.

Transesophageal echocardiography for verification of the position of the electrocardiographically-placed central venous catheter

OBJECTIVE: Compare changes in P-wave amplitude of the intra-atrial electrocardiogram (ECG) and its corresponding transesophageal echocardiography (TEE)-controlled position to verify the exact localization of a central venous catheter (CVC) tip. DESIGN: A prospective study. SETTING: University, single-institutional setting. PARTICIPANTS: Two hundred patients undergoing elective cardiac surgery. INTERVENTIONS: CVC placement via the right internal jugular vein with ECG control using the guidewire technique and TEE control in 4 different phases: phase 1: CVC placement with normalized P wave and measurement of distance from the crista terminalis to the CVC tip; phase 2: TEE-controlled placement of the CVC tip; parallel to the superior vena cava (SVC) and measurements of P-wave amplitude; phase 3: influence of head positioning on CVC migration; and phase 4: evaluation of positioning of the CVC postoperatively using a chest x-ray. MEASUREMENTS AND MAIN RESULTS: The CVC tip could only be visualized in 67 patients on TEE with a normalized P wave. In 198 patients with the CVC parallel to the SVC wall controlled by TEE (phase 2), an elevated P wave was observed. Different head movements led to no significant migration of the CVC (phase 3). On a postoperative chest-x-ray, the CVC position was correct in 87.6% (phase 4). CONCLUSION: The study suggests that the position of the CVC tip is located parallel to the SVC and 1.5 cm above the crista terminalis if the P wave starts to decrease during withdrawal of the catheter. The authors recommend that ECG control as per their study should be routinely used for placement of central venous catheters via the right internal jugular vein.

A standardized protocol for the prevention of clinically relevant venous air embolism during neurosurgical interventions in the semisitting position

OBJECTIVE: We report the results and complications associated with standardized intraoperative management designed for the prevention of hemodynamically relevant venous air embolism during surgery performed in the semisitting position. METHODS: A protocol for preoperative evaluation and intraoperative monitoring was developed and applied in 187 consecutive patients who underwent surgery in the semisitting position between 1999 and 2004. The protocol included preoperative transesophageal echocardiography examination (TEE), intraoperative TEE monitoring, catheterization of the right atrium and a combination of fluid input, positive end expiratory pressure, and standardized positioning aiming at a positive pressure in the transverse and sigmoid sinuses. Data were collected retrospectively from the charts and intraoperative anesthesiological protocols of the patients for the incidence of clinically relevant air embolism (i.e., TEE-diagnosed air embolism plus a decrease in end tidal CO2 or hemodynamic changes) and other complications related to the semisitting position. RESULTS: Three cases (1.6%) of relevant venous air embolism occurred in 187 patients. Only 1 case (0.5%) was hemodynamically relevant, with temporary arterial blood pressure decrease and heart rate increase. Pneumatocephalus leading to lethargy was a frequent postoperative finding, which resolved spontaneously in all except 1 patient with epileptic seizure and oculomotor nerve palsy attributable to space-occupying subdurally trapped air, which had to be treated surgically. There was no permanent morbidity or mortality related to the semisitting position. CONCLUSION: Fear of massive venous air embolism is one reason for dramatic decline in the use of the semisitting position in neurosurgical practice. We found that strict adherence to a standardized protocol using TEE monitoring before and during surgery; exclusion of patients with patent foramen ovale; and a combination of positive end expiratory pressure, fluid input, and a standardized position aiming a positive pressure in the transverse and sigmoid sinuses helped to greatly minimize this complication to a rate of 0.5% for hemodynamically relevant events.

Cell-based therapy facilitates venous thrombus resolution

Endothelial progenitor cells (EPC) are involved in many healing processes in cardiovascular diseases and can be found in spontaneously resolving venous thrombi. The purpose of the present study was to investigate whether the therapeutic administration of EPC might enhance the resolution of venous thrombi. For this purpose, venous thrombosis was induced in the infrarenal inferior vena cava (IVC) in 28 athymic nude rats. Culture expanded EPC derived from human peripheral blood mononuclear cells were injected intravenously two and four days after thrombus induction. Recanalisation of the IVC and thrombus organisation were assessed by laser Doppler measurements of the blood flow and immunohistochemical detection of endothelialised luminal structures in the thrombus. EPC transplantation resulted in significantly enhanced thrombus neovascularisation (capillary density: 186.6 +/- 26.7/HPF vs. 78 +/- 12.3/HPF, p<0.01; area covered by capillaries: 8.9 +/- 1.7 microm(2) vs. 2.5 +/- 1.3 microm(2), p<0.01) and was accompanied by a substantial increase in intra-thrombus blood flow (perfusion ratio: 0.7 +/- 0.07 vs. 0.3 +/- 0.08, p<0.02). These results were paralleled by augmented macrophage recruitment into resolving thrombi in the animals treated with EPC (39.4 +/- 4.7/HPF vs. 11.6 +/- 1.9/HPF, p<0.01). Our data suggest that EPC transplantation might be of clinical value to facilitate venous thrombus resolution in cases where current therapeutic options have limited success.

In search of optimal compression therapy for venous leg ulcers: a meta-analysis of studies comparing diverse [corrected] bandages with specifically designed stockings

OBJECTIVE: In search of an optimal compression therapy for venous leg ulcers, a systematic review and meta-analysis was performed of randomized controlled trials (RCT) comparing compression systems based on stockings (MCS) with divers bandages. METHODS: RCT were retrieved from six sources and reviewed independently. The primary endpoint, completion of healing within a defined time frame, and the secondary endpoints, time to healing, and pain were entered into a meta-analysis using the tools of the Cochrane Collaboration. Additional subjective endpoints were summarized. RESULTS: Eight RCT (published 1985-2008) fulfilled the predefined criteria. Data presentation was adequate and showed moderate heterogeneity. The studies included 692 patients (21-178/study, mean age 61 years, 56% women). Analyzed were 688 ulcerated legs, present for 1 week to 9 years, sizing 1 to 210 cm(2). The observation period ranged from 12 to 78 weeks. Patient and ulcer characteristics were evenly distributed in three studies, favored the stocking groups in four, and the bandage group in one. Data on the pressure exerted by stockings and bandages were reported in seven and two studies, amounting to 31-56 and 27-49 mm Hg, respectively. The proportion of ulcers healed was greater with stockings than with bandages (62.7% vs 46.6%; P < .00001). The average time to healing (seven studies, 535 patients) was 3 weeks shorter with stockings (P = .0002). In no study performed bandages better than MCS. Pain was assessed in three studies (219 patients) revealing an important advantage of stockings (P < .0001). Other subjective parameters and issues of nursing revealed an advantage of MCS as well. CONCLUSIONS: Leg compression with stockings is clearly better than compression with bandages, has a positive impact on pain, and is easier to use.