Efficacy of Dextran Solutions in Vascular Surgery

Dynamic hydrogel-metal-organic framework system promotes bone regeneration in periodontitis through controlled drug delivery

Periodontitis is a prevalent chronic inflammatory disease, which leads to gradual degradation of alveolar bone. The challenges persist in achieving effective alveolar bone repair due to the unique bacterial microenvironment's impact on immune responses. This study explores a novel approach utilizing Metal-Organic Frameworks (MOFs) (comprising magnesium and gallic acid) for promoting bone regeneration in periodontitis, which focuses on the physiological roles of magnesium ions in bone repair and gallic acid's antioxidant and immunomodulatory properties. However, the dynamic oral environment and irregular periodontal pockets pose challenges for sustained drug delivery. A smart responsive hydrogel system, integrating Carboxymethyl Chitosan (CMCS), Dextran (DEX) and 4-formylphenylboronic acid (4-FPBA) was designed to address this problem. The injectable self-healing hydrogel forms a dual-crosslinked network, incorporating the MOF and rendering its on-demand release sensitive to reactive oxygen species (ROS) levels and pH levels of periodontitis. We seek to analyze the hydrogel's synergistic effects with MOFs in antibacterial functions, immunomodulation and promotion of bone regeneration in periodontitis. In vivo and in vitro experiment validated the system's efficacy in inhibiting inflammation-related genes and proteins expression to foster periodontal bone regeneration. This dynamic hydrogel system with MOFs, shows promise as a potential therapeutic avenue for addressing the challenges in bone regeneration in periodontitis.

Open-source hardware- and software-based cryomicroscopy system for investigation of phase transitions in cryobiological research

The development of inexpensive equipment adapted for the study of a specific biological object is very important for cryobiology. In the presented work, we have proposed a simple system for microscopy utilising open-source platform Arduino. Testing this system showed that it had sufficient sensitivity to determine the physical processes occurring in a cryopreserved sample such as intra- and extracellular water crystallisation and salt eutectic. Utilising this system, we investigated the mechanisms of cryoprotection and cryodamage of testis interstitial cells (ICs) in cryoprotective media, which included cryoprotective agents such as dimethyl sulphoxide (Me2 SO), as well as foetal bovine serum or polymers (dextran, hydroxyethyl starch and polyethylene glycol). It was shown that a serum-/xeno-free medium that included 0.7 M Me2 SO and 100 mg/mL dextran was able to reduce intracellular water crystallisation in cells, change the structure of extracellular ice, and reduce salt eutectic and recrystallisation. All these effects correlated with better IC survival after cryopreservation in the medium. This medium is potentially less toxic as it has lower concentrations of Me2 SO compared to serum-containing media developed for cryopreservation of testicular cells. This would pave a way for the creation of nontoxic serum-free compositions that does not require removal before use of cryopreserved living cells for laboratory practice or in clinics.

Intraoperative Infusion of Dextran Confers No Additional Benefit after Carotid Endarterectomy but Is Associated with Increased Perioperative Major Adverse Cardiac Events

BACKGROUND

Intraoperative dextran infusion has been associated with reduction of an embolic risk in patients undergoing carotid endarterectomy (CEA). Nonetheless, dextran has been associated with adverse reactions, including anaphylaxis, hemorrhage, cardiac, and renal complications. Herein, we aimed to compare the perioperative outcomes of CEA stratified by the use of intraoperative dextran infusion using a large multiinstitutional dataset.

METHODS

Patients undergoing CEA between 2008 and 2022 from the Vascular Quality Initiative database were reviewed. Patients were categorized by use of intraoperative dextran infusion, and demographics, procedural data, and in-hospital outcomes were compared. Logistic regression analysis was utilized to adjust for differences in patients while assessing the association between postoperative outcomes and intraoperative infusion of dextran.

RESULTS

Of 140,893 patients undergoing CEA, 9,935 (7.1%) patients had intraoperative dextran infusion. Patients with intraoperative dextran infusion were older with lower rates of symptomatic stenosis (24.7% vs. 29.3%; P < 0.001) and preoperative use of antiplatelets, anticoagulants and statins. Additionally, they were more likely to have severe carotid stenosis (>80%; 49% vs. 45%; P < 0.001) and undergo CEA under general anesthesia (96.4% vs. 92.3%; P < 0.001), with a more frequent use of shunt (64.4% vs. 49.5%; P < 0.001). After adjustment, multivariable analysis showed that intraoperative dextran infusion was associated with higher odds of in-hospital major adverse cardiac events (MACE), including myocardial infarction [MI] (odds ratio [OR], 1.76, 95% confidence interval [CI]: 1.34-2.3, P < 0.001), congestive heart failure [CHF] (OR, 2.15, 95% CI: 1.67-2.77, P = 0.001), and hemodynamic instability requiring vasoactive agents (OR, 1.08, 95% CI: 1.03-1.13, P = 0.001). However, it was not associated with decreased odds of stroke (OR, 0.92, 95% CI: 0.74-1.16, P = 0.489) or death (OR, 0.88, 95% CI: 0.58-1.35, P = 0.554). These trends persisted even when stratified by symptomatic status and degree of stenosis.

CONCLUSIONS

Intraoperative infusion of dextran was associated with increased odds of MACE, including MI, CHF, and persistent hemodynamic instability, without decreasing the risk of stroke perioperatively. Given these results, judicious use of dextran in patients undergoing CEA is recommended. Furthermore, careful perioperative cardiac management is warranted in select patients receiving intraoperative dextran during CEA.

Traversing the diverse avenues of exopolysaccharides-based nanocarriers in the management of cancer

Exopolysaccharides are unique polymers generated by living organisms such as algae, fungi and bacteria to protect them from environmental factors. After a fermentative process, these polymers are extracted from the medium culture. Exopolysaccharides have been explored for their anti-viral, anti-bacterial, anti-tumor, and immunomodulatory effects. Specifically, they have acquired massive attention in novel drug delivery strategies owing to their indispensable properties like biocompatibility, biodegradability, and lack of irritation. Exopolysaccharides such as dextran, alginate, hyaluronic acid, pullulan, xanthan gum, gellan gum, levan, curdlan, cellulose, chitosan, mauran, and schizophyllan exhibited excellent drug carrier properties. Specific exopolysaccharides, such as levan, chitosan, and curdlan, have demonstrated significant antitumor activity. Moreover, chitosan, hyaluronic acid and pullulan can be employed as targeting ligands decorated on nanoplatforms for effective active tumor targeting. This review shields light on the classification, unique characteristics, antitumor activities and nanocarrier properties of exopolysaccharides. In addition, in vitro human cell line experiments and preclinical studies associated with exopolysaccharide-based nanocarriers have also been highlighted.

The usage and outcomes of dextran in the treatment of acute deep venous thrombosis

OBJECTIVES

In this study, we retrospectively compared the outcomes of patients with acute deep vein thrombosis treated with dextran 40 infusion and unfractionated heparin with those of patients treated with unfractionated heparin alone.

METHODS

We evaluated 104 patients with the diagnosis of acute deep vein thrombosis. The pain complaints of the patients at the time of admission and the pain complaints in the calf with dorsiflexion of the foot were evaluated with the visual analogue pain scale, and the calf diameter of affected limbs was measured. Fifty five patients had dextran 40 infusion and unfractionated heparin treatment concomitantly (Group HD), while 49 patients had unfractionated heparin treatment (Group H). Heparin dose was adjusted to obtain 1.5- to 2.5-fold of normal activated partial thromboplastin time in both groups. Oral anticoagulant, warfarin sodium, was administered in the first day and resumed. Unfractionated heparin infusion therapy was resumed until international normalized ratio values of 2-2.5 were obtained. Dextran 40 infusion therapy was administered for 3 days. Calf diameters, current pain, and calf pain at foot dorsiflexion were recorded at 48 h and 72 h. 65 patients were distal, and 39 patients were proximal and popliteal acute DVT. None of the patients had phlegmasia. All were acute DVT.

RESULTS

At 48 and 72 h of therapy, it was determined that the decrease of the calf diameter and the pain were more significant both at 48th and 72nd hours in the Group HD. The calf circumference change, especially at 72 h, was 2.58 ± 0.39 cm in the group receiving heparin + dextran, while it was 1.76 ± 0.56 cm in the group receiving only heparin. (p = 0.000). While there were only 1.24 ± 1.02 people in the group that received dextran at 72 h, leg pain persisted in 3.35 ± 1.11 people in the other group. (p = 0.000). Evaluation was made only with calf vein diameter measurement. When patients with Homan's sign were evaluated for their calf pain at foot dorsiflexion; both groups had decreased pain at 48th and 72nd hours.

CONCLUSION

In this study, we observed that the use of dextran 40 infusion therapy concomitantly with unfractionated heparin accelerates recovery substantially and decreases patient complaints significantly in early stages. In particular, reduction in leg pain and calf circumference reduction were more adequate in the dextran group. The early decrease in the calf circumference will have clinical consequences such as less heparin intake, earlier return to normal life, and a decrease in the total cost of treatment. Since the antithrombotic and anticoagulant effects of dextran are well known, we think that its use in this treatment as well as venous thromboembolism prophylaxis should be discussed.

Pitfalls and promises of bile duct alternatives: A narrative review

Biliodigestive anastomosis between the extrahepatic bile duct and the intestine for bile duct disease is a gastrointestinal reconstruction that abolishes duodenal papilla function and frequently causes retrograde cholangitis. This chronic inflammation can cause liver dysfunction, liver abscess, and even bile duct cancer. Although research has been conducted for over 100 years to directly repair bile duct defects with alternatives, no bile duct substitute (BDS) has been developed. This narrative review confirms our understanding of why bile duct alternatives have not been developed and explains the clinical applicability of BDSs in the near future. We searched the PubMed electronic database to identify studies conducted to develop BDSs until December 2021 and identified studies in English. Two independent reviewers reviewed studies on large animals with 8 or more cases. Four types of BDSs prevail: Autologous tissue, non-bioabsorbable material, bioabsorbable material, and others (decellularized tissue, 3D-printed structures, etc.). In most studies, BDSs failed due to obstruction of the lumen or stenosis of the anastomosis with the native bile duct. BDS has not been developed primarily because control of bile duct wound healing and regeneration has not been elucidated. A BDS expected to be clinically applied in the near future incorporates a bioabsorbable material that allows for regeneration of the bile duct outside the BDS.

Phase transitions and mechanisms of cryoprotection of serum-/xeno-free media based on dextran and dimethyl sulfoxide

The development of serum-/xeno-free media may help avoid the drawbacks of using serum and its components, such as probable contamination, instability of composition, or difficulty in sterilization. The objectives of this research were to investigate the use of combinations of a permeating cryoprotective agent (Me₂SO) and non-permeating (polyvinyl alcohol, polyvinylpyrrolidone, polyethylene glycol, hydroxyethyl starch, dextran) polymers for cryopreservation of interstitial cells (ICs) of rat testis, and to propose the mechanism of cryoprotection of such compositions. In the course of this study, the best combination was 100 mg/ml dextran (M.m. 40 kDa) (Dex40) with 0.7 M Me₂SO in Ham's F12. The ICs were additionally cooled and warmed to different end temperatures (-30, -50, -50 and -196 °C) to determine which temperature intervals contributed most to the IC loss. Then, the cryoprotective action of this serum-/xeno-free medium was investigated in comparison with serum or albumin-containing media by differential scanning calorimetry (DSC) and thermomechanical analysis (TMA). The results showed that the medium based on Dex40 did not decrease the amount of ice formed. However, it could undergo other phase separation and phase transformation to form glassy states. Potential cell-damaging physical processes such as eutectic crystallization/melting, recrystallization of NaCl and/or Me₂SO derivatives, found in serum-containing media and taking place in specific temperature intervals, were not observed in the Dex40 based media. This was in good correlation with indicators of cell survival. Additionally, the application of Dex40 allowed using Me₂SO in lower concentrations (0.7 M) than required for serum-containing media (1.4 M), which may decrease the toxicity of serum-/xeno-free media.

Protein-free solution containing trehalose and dextran 40 for cryopreservation of human adipose tissue-derived mesenchymal stromal cells

We tested the efficacy of lactated Ringer's solution with 3% trehalose and 5% dextran 40 (LR-3T-5D) as a vehicle solution for cryopreservation using human adipose-derived mesenchymal stromal cells (hADSCs) with dimethyl sulfoxide (Me2SO). We also tested the effect of the Me2SO concentration in the cryopreservation solution, and the effect of washing with lactated Ringer's solution with 3% trehalose (LR-3T) and replacement with LR-3T or LR-3T-5D. LR-3T-5D was more effective for cell viability, viable cell recovery ratio, annexin V-positive ratio, and colony-forming capacity as a vehicle solution for cryopreservation with 10% Me2SO than LR. The additive effects as cryoprotectants of trehalose and dextran 40 were confirmed to be dose dependent. The cell viability, cell proliferation ability, cell differentiation ability, and the ratio of cell surface positive/negative markers of hADSCs were well maintained after cryopreservation with LR-3T-5D containing 10% Me2SO in liquid nitrogen or in a -80 °C freezer. The cell viability and the proliferation curve in LR-3T-5D with 5% Me2SO were comparable to those with 10% Me2SO. LR-3T-5D was superior to LR-3T as a replacement solution in terms of viability and annexin V positivity. Our data showed that LR-3T-5D is effective as a vehicle solution for cryopreservation. Reducing Me2SO concentration to 5%, and washing and replacement with fresh LR-3T and LR-3T-5D after thawing, are feasible approaches to maintain cryopreservation efficacy.

Gd(DOTA)-grafted submicronic polysaccharide-based particles functionalized with fucoidan as potential MR contrast agent able to target human activated platelets

Early detection of thrombotic events remains a big medical challenge. Dextran-based submicronic particles bearing Gd(DOTA) groups and functionalized with fucoidan have been produced via a simple and green water-in-oil emulsification/co-crosslinking process. Their capacity to bind to human activated platelets was evidenced in vitro as well as their cytocompatibility with human endothelial cells. The presence of Gd(DOTA) moieties was confirmed by elemental analysis and total reflection X-ray fluorescence (TRXF) spectrometry. Detailed characterization of particles was performed in terms of size distribution, morphology, and relaxation rates. In particular, longitudinal and transversal proton relaxivities were respectively 1.7 and 5.0 times higher than those of DOTAREM. This study highlights their potential as an MRI diagnostic platform for atherothrombosis.

Comparison of dextran and albumin on blood coagulation in patients undergoing major gynaecological surgery

Background

Hydroxyethyl starches have been withdrawn from the European market. In Sweden, dextran was the main colloid until 2000, when starches overtook the market. After the recent 6S-trial, it was suggested that dextran could be reinstituted, but concerns for greater coagulopathy, bleeding and anaphylaxis still remain. An experimental study from our department indicated that isovolemic substitution of dextran-70 did not derange the von Willebrand function more than albumin 5%, considering the fact that dextran is hyperoncotic in comparison to albumin 5% and, therefore, induces a greater plasma volume expansion and thereby a greater dilutional coagulopathy.

Methods

Eighteen patients undergoing major gynaecological surgery were assigned to receive either 5% albumin or 6% dextran-70 with 9 patients in each group. Standard coagulation tests, including prothrombin time (PT), activated partial thromboplastin time (aPTT), fibrinogen and platelet count, viscoelastic coagulation test thromboelastometry (ROTEM) and the Multiplate platelet aggregation test were used to test for coagulation defects at different time points perioperatively. Blood loss, blood loss replacement data and haemodynamic parameters were retrieved from anaesthetic and postoperative charts. A local departmental fluid and transfusion/infusion protocol assured haemoglobin > 90 g/l and mean arterial pressure > 65 mmHg with Ringer’s acetate in addition to the colloid use.

Results

There were no differences in demographic data between the groups. The tissue factor-activated (EXTEM) clot-structure parameter ROTEM A10 was decreased significantly in the dextran group as compared to the albumin group after the infusion of 500 ml of either colloid solution. The PT and aPTT were significantly prolonged, and the platelet count decreased postoperatively in the dextran group, whereas albumin only deranged fibrinogen levels as compared to preoperative levels. There were no differences in Multiplate platelet aggregometry, amount of haemorrhage or transfusion of blood components between the groups.

Conclusions

Standard plasma-based coagulation tests, platelet count and whole blood viscoelastic clot structure are affected by 6% dextran-70 to a greater extent than by 5% albumin, but platelet aggregation is not. Future studies should use more advanced haemodynamic monitoring to assess isovolemic plasma volume expansion with dextran and whether this affects haemostasis to a lesser degree.

In vitro evaluation of the effect of haemodilution with dextran 40 on coagulation profile as measured by thromboelastometry and multiple electrode aggregometry

We evaluated the effects of haemodilution with either dextran 40 or 0.9% normal saline on coagulation in vitro using rotational thromboelastometry (ROTEM®, Pentapharm Co., Munich, Germany) and multiple electrode aggregometry (Multiplate® Platelet Function Analyser, Dynabyte, Munich, Germany). Venous blood samples obtained from 20 healthy volunteers were diluted in vitro with dextran 40 or normal saline by 5%, 10% and 15%. Fibrinogen concentration, ROTEM-EXTEM® (screening test for the extrinsic coagulation pathway), FIBTEM® (an EXTEM-based assay of the fibrin component of clot) parameters including coagulation time, clot formation time, alpha angle, maximum clot firmness and lysis index were measured in the undiluted sample and at each level of haemodilution. Dextran 40 at 15% haemodilution significantly prolonged coagulation time, clot formation time and significantly decreased the alpha angle and maximal clot firmness (EXTEM amplitude at five minutes [A5] and ten minutes [A10]) compared with normal saline. The FIBTEM assay (maximal clot firmness and FIBTEM A5 and A10) showed a marked decrease in maximal clot firmness at all dilutions suggesting impaired fibrinogen activity and a risk of bleeding. Multiple electrode aggregometry did not demonstrate any platelet dysfunction. Haemodilution with dextran 40 causes significant impairment in clot formation and strength compared to saline haemodilution and undiluted blood. At the levels of in vitro haemodilution designed to reflect the clinical use of dextran infusions, no significant fibrinolysis or platelet inhibition was observed.

Long term performance evaluation of small-diameter vascular grafts based on polyvinyl alcohol hydrogel and dextran and MSCs-based therapies using the ovine pre-clinical animal model

The functional and structural performance of a 5cm synthetic small diameter vascular graft (SDVG) produced by the copolymerization of polyvinyl alcohol hydrogel with low molecular weight dextran (PVA/Dx graft) associated to mesenchymal stem cells (MSCs)-based therapies and anticoagulant treatment with heparin, clopidogrel and warfarin was tested using the ovine model during the healing period of 24 weeks. The results were compared to the ones obtained with standard expanded polyetetrafluoroethylene grafts (ePTFE graft). Blood flow, vessel and graft diameter measurements, graft appearance and patency rate (PR), thrombus, stenosis and collateral vessel formation were evaluated by B-mode ultrasound, audio and color flow Doppler. Graft and regenerated vessels morphologic evaluation was performed by scanning electronic microscopy (SEM), histopathological and immunohistochemical analysis. All PVA/Dx grafts could maintain a similar or higher PR and systolic/diastolic laminar blood flow velocities were similar to ePTFE grafts. CD14 (macrophages) and α-actin (smooth muscle) staining presented similar results in PVA/Dx/MSCs and ePTFE graft groups. Fibrosis layer was lower and endothelial cells were only detected at graft-artery transitions where it was added the MSCs. In conclusion, PVA/Dx graft can be an excellent scaffold candidate for vascular reconstruction, including clinic mechanically challenging applications, such as SDVGs, especially when associated to MSCs-based therapies to promote higher endothelialization and lower fibrosis of the vascular prosthesis, but also higher PR values.

In vitro and in vivo evaluation of blood coagulation activation of polyvinyl alcohol hydrogel plus dextran-based vascular grafts

Polyvinyl alcohol hydrogel (PVA) is a water-soluble synthetic polymer that is commonly used in biomedical applications including vascular grafting. It was argued that the copolymerization of PVA with dextran (Dx) can result in improvement of blood-biomaterial interactions. The focus of this experimental study was to assess that interaction through an in vivo and in vitro evaluation of the coagulation system activation. The thrombogenicity of the copolymer was determined by quantification of platelet adhesion through the lactate dehydrogenase assay, determination of whole blood clotting time, and by quantification of platelet activation by flow cytometry. The thrombin-antithrombin complex blood levels were also determined. The obtained results for the in vitro assays suggested a non-thrombogenic profile for PVA/Dx. Additionally in vivo coagulation and hematological parameters were determined in an animal model after PVA/Dx vascular graft implantation. For coagulation homeostasis assessment, the intrinsic and extrinsic pathway's activation was determined by measuring prothrombin time (PT) and activated partial thromboplastin time (aPTT). Other markers of coagulation and inflammation activation including d-dimers, interleukin-6, and C-reactive protein were also assessed. The PVA/Dx copolymer tended to inhibit platelet adhesion/activation process and the contact activation process for coagulation. These results were also confirmed with the in vivo experiments where the measurements for APTT, interleukin-6, and C-reactive protein parameters were normal considering the species normal range of values. The response to those events is an indicator of the in vitro and in vivo hemocompatibility of PVA/Dx and it allows us to select this biomaterial for further preclinical trials in vascular reconstruction.

Biocompatibility and hemocompatibility of polyvinyl alcohol hydrogel used for vascular grafting--In vitro and in vivo studies

Polyvinyl alcohol hydrogel (PVA) is a synthetic polymer with an increasing application in the biomedical field that can potentially be used for vascular grafting. However, the tissue and blood-material interactions of such gels and membranes are unknown in detail. The objectives of this study were to: (a) assess the biocompatibility and (b) hemocompatibility of PVA-based membranes in order to get some insight into its potential use as a vascular graft. PVA was evaluated isolated or in copolymerization with dextran (DX), a biopolymer with known effects in blood coagulation homeostasis. The effects of the mesenchymal stem cells (MSCs) isolated from the umbilical cord Wharton's jelly in the improvement of PVA biocompatibility and in the vascular regeneration were also assessed. The biocompatibility of PVA was evaluated by the implantation of membranes in subcutaneous tissue using an animal model (sheep). Histological samples were assessed and the biological response parameters such as polymorphonuclear neutrophilic leucocytes and macrophage scoring evaluated in the implant/tissue interface by International Standards Office (ISO) Standard 10993-6 (annex E). According to the scoring system based on those parameters, a total value was obtained for each animal and for each experimental group. The in vitro hemocompatibility studies included the classic hemolysis assay and both human and sheep bloods were used. Relatively to biocompatibility results, PVA was slightly irritant to the surrounding tissues; PVA-DX or PVA plus MSCs groups presented the lowest score according to ISO Standard 10993-6. Also, PVA was considered a nonhemolytic biomaterial, presenting the lowest values for hemolysis when associated to DX.

Intraoperative use of dextran is associated with cardiac complications after carotid endarterectomy

OBJECTIVE

Although dextran has been theorized to diminish the risk of stroke associated with carotid endarterectomy (CEA), variation exists in its use. We evaluated outcomes of dextran use in patients undergoing CEA to clarify its utility.

METHODS

We studied all primary CEAs performed by 89 surgeons within the Vascular Study Group of New England database (2003-2010). Patients were stratified by intraoperative dextran use. Outcomes included perioperative death, stroke, myocardial infarction (MI), and congestive heart failure (CHF). Group and propensity score matching was performed for risk-adjusted comparisons, and multivariable logistic and gamma regressions were used to examine associations between dextran use and outcomes.

RESULTS

There were 6641 CEAs performed, with dextran used in 334 procedures (5%). Dextran-treated and untreated patients were similar in age (70 years) and symptomatic status (25%). Clinical differences between the cohorts were eliminated by statistical adjustment. In crude, group-matched, and propensity-matched analyses, the stroke/death rate was similar for the two cohorts (1.2%). Dextran-treated patients were more likely to suffer postoperative MI (crude: 2.4% vs 1.0%; P = .03; group-matched: 2.4% vs 0.6%; P = .01; propensity-matched: 2.4% vs 0.5%; P = .003) and CHF (2.1% vs 0.6%; P = .01; 2.1% vs 0.5%; P = .01; 2.1% vs 0.2%; P < .001). In multivariable analysis of the crude sample, dextran was associated with a higher risk of postoperative MI (odds ratio, 3.52; 95% confidence interval, 1.62-7.64) and CHF (odds ratio, 5.71; 95% confidence interval, 2.35-13.89).

CONCLUSIONS

Dextran use was not associated with lower perioperative stroke but was associated with higher rates of MI and CHF. Taken together, our findings suggest limited clinical utility for routine use of intraoperative dextran during CEA.

Potential role of PMD-TCD monitoring in the management of hemodynamically unstable intracranial stenosis

A 54-year-old woman started to loose vision 2 days prior to admission and also experienced left-sided headache, nausea, emesis, and disorientation. Magnetic resonance imaging (MRI) revealed bilateral posterior cerebral artery and cerebellar infarctions. Transcranial power motion Doppler (PMD-TCD) showed blunted flow signal in the proximal basilar artery (BA) suggestive for a high-grade stenosis also seen on magnetic resonance angiography (MRA). Dual antiplatelet therapy with aspirin and clopidogrel was started. Catheter angiography confirmed the proximal high-grade BA stenosis. After angiography, the patient experienced hypertensive crisis with severe headache. Blood pressure was lowered and headache resolved. One hour later she developed fluctuating level of consciousness and motor symptoms. PMD-TCD findings were suggestive for an intraluminal thrombus that moved from the proximal to the distal basilar artery, presumably further contributing to brain stem hypoperfusion and neurological deterioration. To achieve a compromise between lower blood pressure and maintenance of brain perfusion, hypervolemic hemodilution with intravenous dextran-40 was initiated. Patient's symptoms resolved to baseline and MRI showed no new parenchymal lesions.

Anaphylactoid reactions to Dextran 40 and 70: Reports to the United States Food and Drug Administration, 1969 to 2004

BACKGROUND

Clinical dextrans, such as Dextran 40 and Dextran 70, are associated with anaphylactoid reactions caused by dextran-reactive immunoglobulin G antibodies. When infused immediately before clinical dextrans, dextran 1 significantly reduces the incidence of severe anaphylactoid reactions. The objective of the study was to describe the frequency and characteristics of reports submitted to the United States Food and Drug Administration (FDA) for anaphylaxis or anaphylactoid events after clinical dextran administration.

METHODS

We searched the FDA's Adverse Event Reporting System for reports associated with a clinical dextran and describing anaphylaxis/anaphylactoid reactions. Our case definition for a probable anaphylaxis/anaphylactoid event required signs or symptoms from at least two body systems, with at least one sign or symptom being hypotension, vasodilation, or respiratory difficulty, and onset within 60 minutes. Other reports were considered possible cases if the reporter specifically described the reaction as anaphylaxis or an anaphylactoid reaction. Premier RxMarket Advisor provided estimates of total US hospitalizations with clinical dextran or dextran 1 administration from 2000 to 2004, based on discharge billing data from a sample of US hospitals. The IMS National Sales Perspective provided estimates of total doses of dextrans sold in the United States from 1999 to 2004, based on volumes of dextrans sold in a sample of retail and nonretail outlets.

RESULTS

The FDA received 366 clinical dextran adverse event reports from 1969 to 2004, of which 90 (24.6%) were anaphylaxis/anaphylactoid events. The ratio of hospitalizations where clinical dextran was administered to hospitalizations where dextran 1 was administered was 28.4:1. The expected ratio would be 1:1 if all clinical dextran patients had received dextran 1 pretreatment. The ratio of clinical dextran doses sold to dextran 1 doses sold in the United States was 38.6:1.

CONCLUSIONS

A high proportion of adverse event reports for clinical dextrans described anaphylaxis or anaphylactoid reactions. Hospital discharge and product sales data suggest that dextran 1 has not been used consistently before clinical dextran administration in recent years. To reduce the risk of anaphylactoid reactions, physicians should consider routine administration of dextran 1 before the infusion of a clinical dextran.