Dextran and the prevention of postoperative thromboembolic complications

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.

Optical Coherence Tomography-Guided Percutaneous Coronary Intervention With Low-Molecular-Weight Dextran - Effect on Renal Function

BACKGROUND

The excessive volume of contrast needed is a significant limitation of optical coherence tomography (OCT)-guided percutaneous coronary intervention (PCI). Low-molecular-weight dextran (LMWD) has been used for OCT image acquisition instead of contrast media. This study compared the effects of OCT-guided PCI using LMWD on renal function and clinical outcomes to those of intravascular ultrasound (IVUS)-guided PCI.

METHODS AND RESULTS

In all, 1,183 consecutive patients who underwent intracoronary imaging-guided PCI were enrolled in this single-center, retrospective, observational study. After propensity score matching, 133 pairs of patients were assigned to undergo either OCT-guided PCI using LMWD or IVUS-guided PCI. There was no significant change from baseline in the primary endpoint, serum creatinine concentrations, after the procedure in either group. There were no significant differences between the OCT and IVUS groups in the volume of contrast medium, the incidence of contrast-induced nephropathy (1.5% vs. 2.3%; P=0.65), and major adverse cardiovascular events (MACE) at 30 days (2.3% vs. 6.0%; P=0.12) and 12 months (2.3% vs. 3.0%; P=0.70) after the procedure. Kaplan-Meier analysis at the 12-month follow-up revealed no significant difference in the incidence of MACE between the 2 groups (P=0.75).

CONCLUSIONS

OCT-guided PCI using LMWD did not negatively affect renal function and achieved similar short- and long-term clinical outcomes to IVUS-guided PCI.

Venous Thromboembolism Prophylaxis in the Surgical Patient

A questionnaire designed to assess actual practice with regard to venous thromboembolism prophylaxis (VTEP) was mailed to 100 general surgeons. Although a majority (78%) of the respondents (n = 65) indicated that they used some form of VTEP, the methods used were inadequate to protect high-risk and moderate-risk patients from thromboembolic complications. Furthermore, pulmonary embolism was not perceived as a significant prob lem by most (64%) of the respondents who did not use prophylaxis.

Clinically manifest thromboembolic complications of femoral vein catheterization for continuous renal replacement therapy

PURPOSE

The safety of femoral vein (FV) catheterization for continuous renal replacement therapy is uncertain. We sought to determine the incidence of clinically manifest venous thromboembolism (VTE) in such patients.

METHODS

We retrospectively studied patients with femoral high flow catheters (≥ 13F) (December 2005 to February 2011). Discharge diagnostic codes were independently screened for VTE. The incidence of VTE was also independently similarly assessed in a control cohort of patients ventilated for more than 2 days (January 2011 to December 2011) in the same intensive care unit (ICU).

RESULTS

We studied 380 patients. Their mean age was 61 years, and 59% were male. The mean Acute Physiology and Chronic Health Evaluation III score was 84; average duration of continuous renal replacement therapy was 74 hours, and 232 patients (61%) survived to hospital discharge with an average length of hospital stay of 22 days. Only 5 patients (1.3%) had clinically manifest VTE after FV catheterization. In the control cohort of 514 ICU patients, the incidence of VTE was 4.4% (P < .05 compared with FV group).

CONCLUSION

The incidence of clinically manifest VTE after FV catheterization with high flow catheters is low and lower to that seen in general ICU patients.

Venous thromboembolism after surgery for benign prostatic hyperplasia

A systematic review has been performed on venous thromboembolism after surgery for benign prostatic hyperplasia. The risk of deep vein thrombosis is two to four times higher after open surgery than after transurethral resection. The risk after the newer transurethral methods (laser, radiofrequency, heat) is not known. Specific studies on thromboprophylaxis are few and have limited numbers of patients. Nonetheless, thromboprophylaxis (heparin) reduces the frequency of postoperative deep vein thrombosis after open surgery. Studies on patients undergoing transurethral resection are lacking. Antifibrinolytic treatment to diminish bleeding does not seem to increase the risk of thrombosis.

Comparison of postoperative coumarin, dextran 40 and subcutaneous heparin in the prevention of postoperative deep vein thrombosis

A double-blind study was carried out to investigate the effectiveness of several preventive regimens in postoperative deep vein thrombosis (DVT). The regimens consisted of postoperative (p.o.) acenocoumarin, dextran 40 + p.o. acenocoumarin, subcutaneous (s.c.) heparin alone and s.c. heparin + p.o. acenocoumarin. The 313 patients studied were stratified according to age (40-60 vs. less than 60 years) and type of operation (laparotomy, thoracotomy, hip replacement). Dextran 40 + p.o. acenocoumarin was more effective than p.o. acenocoumarin alone, which acted as control. Subcutaneous heparin alone or together with p.o. acenocoumarin was not more effective than p.o. acenocoumarin alone during the first part of the study, when about 4000 IU twice daily were administered accidentally. When the dose had been changed to 5000 IU twice daily, better results were obtained (DVT) incidence 5.9%). The results were strongly influenced by age and type of operation. Almost no DVT occurred in patients below 60 years of age with elective abdominal surgery. The incidence of perfusion disturbances in lung scans in patients with DVT was lowest in those treated with s.c. heparin in combination with acenocoumarin.

Comparative study of isovolemic hemodilution with 3% albumin, dextran-40, and prophylactic enoxaparin (LMWH) on thrombus formation at venous microanastomosis in rats

The objective of the present investigation was to compare the effect of isovolemic hemodilution with 3% albumin, dextran-40, and enoxaparin on the prevention of thrombosis in femoral vein microanastomosis using an experimental model in rats. Forty male Wistar rats were allocated into four groups: group 1, control, thrombogenic model without previous treatment; group 2, hemodiluted, thrombogenic model with previous hemodilution; group 3, dextran-40, thrombogenic model with dextran infusion (10 ml/kg), and group 4, enoxaparin, thrombogenic model with administration of enoxaparin (0.5 mg/kg/day). Hemostatic parameters, hematologic examinations, patency of anastomosis, and histopathological examination were evaluated. The hemostatic parameters were similar in the four groups studied. Group hemodiluted, dextran-40, and enoxaparin showed significantly reduced number of red blood cells and platelets as compared with the control group. The hemodilution significantly increased the patency rates of the vein at 20 min and 48 h. Dextran-40 and enoxaparin improved the patency of the vein only at 20 min, but failed to show a significant increase in the final patency at 48 h. After 48 h, the rate of venous thrombosis, as evaluated microscopically, was significantly decreased in hemodiluted animals (1/8) as compared with controls (10/10); in rats treated with dextran-40 (7/10) and enoxaparin (5/10) the rate of venous thrombosis was significantly higher as compared with rats of the group hemodiluted. Based on these observations, it can be concluded that hemodilution with albumin 3% was a safe and more adequate procedure than the use of the schemes of administration of dextran-40 and enoxaparin used in this study to prevent thrombus formation at femoral vein microanastomosis in rats. Since hemodilution promotes reduction in blood viscosity and in erythrocyte and platelet aggregation as well as dilution of the coagulation factors themselves, its use could provide better microcirculatory blood perfusion, decreasing the risk of thrombosis, and making possible safer microsurgical procedures.

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.

Isovolemic hemodilution with dextran 60 as treatment of pancreatic ischemia in acute pancreatitis. Clinical practicability of an experimental concept

OBJECTIVE

This phase-I study transferred the concept of isovolemic hemodilution, which has been proven beneficial in the treatment of experimental acute pancreatitis to the patient.

SUMMARY BACKGROUND DATA

Pancreatic ischemia represents one main mechanism in the pathogenesis of necrotizing pancreatitis. Isovolemic hemodilution with dextran 60 has been shown experimentally to limit the progression of pancreatic necrosis by improving pancreatic microcirculation.

METHODS

Thirteen patients with clinically severe nonbiliary pancreatitis and CT-classification E according to Balthazar were enrolled. Exclusion criteria were anemia, coronary heart disease, chronic obstructive pulmonary disease, coagulopathies, and secondary referral. The volume of blood to be exchanged for dextran 60 was calculated from a nomogram based on body surface. Isovolemic hemodilution aimed at a hematocrit of 30%. Independent from the exchange procedure conventional fluid resuscitation was performed to adjust the central venous pressure at 6 +/- 2 mm Hg.

RESULTS

Whole blood (750-1,700 mL) was exchanged for dextran 60 during 45 to 70 minutes. No adverse effect was encountered; central hemodynamics were not affected. Considering a mean Ranson score of 5, mortality was low (7.7%). Progression of pancreatic necrosis was registered in only two patients subsequently undergoing surgical treatment (15%).

CONCLUSIONS

Isovolemic hemodilution is practicable in patients. A randomized trial has to prove whether isovolemic hemodilution can substantially alter the course of acute pancreatitis as anticipated from animal studies.

Therapeutic effect of isovolemic hemodilution with dextran 60 on the impairment of pancreatic microcirculation in acute biliary pancreatitis

Dextran of different molecular weight (Dx 40, Dx 60/70) has often been evaluated as adjunct treatment of experimental acute pancreatitis. A beneficial effect has been documented by a decrease in its lethality. However, the mechanism of action is poorly understood. A specific effect on the pancreatic microcirculation generally has not been documented and differentiation from unspecific improvement of pancreatic blood flow due to volume expansion has been difficult. This investigation was designed to quantify the effect of dextran on the impairment of pancreatic microcirculation during acute biliary pancreatitis by means of intravital microscopy. Dextran 60 (Dx 60, molecular weight 60,000) was chosen in light of the increase in vascular permeability in the early stage of pancreatitis as demonstrated previously in the same model. Isovolemic hemodilution, i.e., exchange of whole blood for Dx 60 was used as a mode of administration to achieve instantaneous onset of therapy without changes in intravascular volume. In the control group a progressive reduction of pancreatic capillary perfusion commenced 30 minutes after induction of acute pancreatitis, resulting in cessation of nutritive tissue perfusion after 3 hours. In the animals subjected to hemodilution, stabilization of the pancreatic microcirculation was accomplished throughout the observation period of 6 hours. Because volume-related effects could be excluded by the protocol and by monitoring central venous pressure and hematocrit, a specific effect of hemodilution with DX 60 on the pancreatic microcirculation is indicated by our results.

Diagnosis and treatment of recurrent venous thromboembolism

The diagnosis of recurrent venous thromboembolism includes an evaluation of the patient for inherited or acquired disorders, associated with an increased risk of thromboembolism. Treatment depends, in part, on the underlying disease and, in part, on an adequate understanding of the principles of anticoagulant therapy.

Low molecular weight dextran in experimental pancreatitis: effects on pancreatic microcirculation

Although low molecular weight (LMW) dextran has been said to decrease the lethality of experimental acute pancreatitis (AP) by reversing stasis in the pancreatic microcirculation, the actual mechanism(s) of action is unknown. This investigation was designed to measure the effects of low molecular weight dextran on pancreatic capillary flow (QCAP) and arteriovenous shunt flow (QAVS), and on pancreatic oxygen consumption (O2CP) following bile-trypsin-induced AP in dogs. Total pancreatic blood flow (QT) was measured with an electromagnetic flow probe on the superior pancreaticoduodenal artery (SPDA). QAVS was measured by liver trapping of 99mTc-albumin microspheres after SPDA injection. QCAP was calculated as QT minus QAVS. Seventeen dogs were treated with lactated Ringer's (LR) solution at 6.5 ml/kg/hr; 10 dogs were treated with LMW dextran 10% in normal saline at 1.5 ml/kg/hr plus LR at 5.0 ml/kg/hr. Mean arterial and central venous pressures remained constant throughout the 4-hr experiment. In the dogs receiving LR only, QT decreased from 42.7 to 24.4 ml/min (P less than 0.001); QAVS remained constant at 1.35 +/- 0.04 ml/min. During the first 30 min O2CP decreased from 1.17 to 0.76 ml O2/min (P less than 0.05) and remained constant thereafter. LMW dextran treatment altered none of these hemodynamic or metabolic parameters significantly.

CONCLUSIONS

bile trypsin AP in the dog causes significant decreases in QT and QCAP without altering QAVS. The decrease in O2CP in association with a constant QAVS suggests a metabolic block to oxygen uptake at the cellular level. Continuous infusion of LMW dextran at a dose of 1.5 ml/kg/hr in the dog does not reverse these abnormalities.

Prevention of fatal postoperative pulmonary embolism by heparin dihydroergotamine or Dextran 70

Eight thousand and one patients were admitted to a prospective, randomized multicentre trial comparing the prophylactic efficacy of heparin-dihydroergotamine (DHE) and Dextran 70 against fatal pulmonary embolism after emergency or elective orthopaedic surgery. Of the 7413 patients correctly admitted to the trial, 3698 were allocated to receive heparin-DHE and 3715 to receive Dextran 70. Twenty-eight patients in the heparin-DHE and 27 in the dextran group died within 40 days of operation. Necropsy was performed in 19 cases in each group. In 6 patients in the heparin-DHE and in 9 in the dextran group pulmonary embolism was the sole or a contributory cause of death (n.s.). In the dextran group there were more diffuse intraoperative bleeding complications (P less than 0.01), more massive postoperative haemorrhages (P less than 0.01), more small wound haematomas (P less than 0.05) and more allergic reactions (P less than 0.05). This is the first large multicentre trial dealing with elective and emergency procedures in orthopaedic patients.

A comparative study of Dextran 70 and a sulphated polysaccharide in the prevention of postoperative thromboembolic complications

A prospective randomized study has been performed, comparing a semisynthetic polysulphated xylan of vegetable origin (mol. wt approximately 4000) with Dextran 70 as prophylactic agent against postoperative thromboembolic complications following elective abdominal surgery. A total of 109 patients entered the trial and the analysis after exclusions is based on 86 patients. The overall frequency of 125I-labelled fibrinogen test-detected thrombosis was 2.9 per cent in the polysaccharide group against 19.2 per cent in the Dextran 70 group (P less than 0.05). There was no difference in haemorrhage or different complications.

Thrombosis: the relationship of hemostatic mechanisms to drug therapy

The mechanism of action and present clinical role of drugs affecting hemostasis in the therapy of spontaneous, postoperative, and posttraumatic arterial thrombosis, arterial embolism, venous thrombosis, pulmonary embolism, and intracranial aneurysm have been reviewed. Both the management of neurosurgical problems and the development of antithrombotic regimens are improving. In regard to the use of drug therapy, discussed herein, each surgeon will reach his own decision based on his findings in the individual patient, and may wisely elect in specific situations not to employ drug therapy. The comments offered in ths analysis are to be construed as suggestions not mandates, as they will undoubtedly undergo modification with time. In closing, it is appropriate to recall a famous Chinese curse: "May you live," it reads, "in a time of transition."

Incidences of fatal postoperative pulmonary embolism after prophylaxis with dextran 70 and low-dose heparin: an international multicentre study

A total of 4352 patients were admitted to a prospective' randomised multicentre trial comparing the prophylactic efficacy of dextran 70 and low-dose heparin against fatal pulmonary embolism after elective operations for general, orthopaedic, urological, and gynaecological conditions. Out of 3984 patients correctly admitted, 1993 were allocated to receive dextran 70 and 1991 to receive low-dose heparin. Withdrawal of prophylaxis because of bleeding or technical difficulties occurred more often in the heparin group, but allergic reactions were more common in the dextran group. Of the 75 patients who died within 30 days after operation, 38 had been given dextran and 37 low-dose heparin. Necropsy was performed in 33 and 32 of these cases respectively. In six patients in each group pulmonary embolism was the sole or a contributory cause of death. Of these, five patients in the dextran group and two in the heparin group had received a full course of prophylaxis. There was no statistically significant difference between the two treatment groups in the incidence of fatal pulmonary embolism after a full course of prophylaxis.

Preoperative normovolaemic haemodilution with dextran 70 as a thromboembolic prophylaxis in total in hip replacement

The effect of preoperative normovolaemic haemodilution with dextran 70 in 57 patients undergoing total hip replacement for osteoarthritis, was evaluated with respect to the production of thrombosis and pulmonary embolism. The patients were randomly allocated to one group undergoing preoperative haemodilution and one control group receiving 500 ml dextran 70 during operation and again on the second postoperative day. Before operation blood was replaced by dextran 70 to lower the hematocrit to between 25 and 30. The blood drained from the patients was used to replace blood lost at operation. Between 10 and 14 days after operation the patients were examined by perfusion lung scan, chest radiography and bilateral phlebography. Twelve patients also had 133Xe ventilation scans. The incidence of deep vein thrombosis in the two groups did not differ significantly. Pulmonary embolism was significantly decreased in the preoperative haemodilution group. One patient in the control group had clinical symptoms of, and died from, pulmonary embolism.

Acute renal vein thrombosis with dextran treatment

The case of a 35-year-old woman with active ulcerative colitis and acute left renal vein thrombosis is presented. The successful management of this patient with dextran-70 is contrasted with other modes of therapy used currently.

Prevention of postoperative thromboembolism by dextran 40, low doses of heparin, or xantinol nicotinate

The efficacy of dextran-40 infusions or low-dose heparin or xantinol-nicotinate administration in preventing postoperative thromboembolic complications has been investigated in a prospective, controlled, randomised trial as part of an international multicentre trial. 382 patients over the age of forty years undergoing elective major general surgery were investigated; 100 had a complete protocol in the control, 94 in the heparin, 92 in the dextran, and 32 in the xantinol-nicotinate group. 31 patients died: 13 in the control group, 10 in the heparin group, 6 in the dextran group, and 2 in the xantinol-nicotinate group. In 4 controls, 6 in the heparin group, and 1 in the dextran group the cause of death was acute pulmonary embolism. 4 further controls, 1 in the heparin group, and 2 in the dextran group had emboli found at necropsy, which either contributed to the deaths or were incidental findings. The distribution of pulmonary emboli in this study did not show the difference between the control and the heparin group reported in the multicentre trial. The 125I-fibrinogen test was done in all patients. The frequency of isotopic deep-vein thrombosis was 36-0% in the controls, 12-8% in the heparin group, 21-7% in the dextran group, and 40-6% in the xantinol-nicotinate group. The difference between the controls and the heparin groups was highly significant and between the control and the dextran group, probably significant. There were significantly more side-effects in the heparin group than in the dextran group.