Swine Femoral Artery Research Articles

Self-Oxidated Hydrophilic Chitosan Fibrous Mats for Fatal Hemorrhage Control.

Enriching erythrocytes and platelets in seconds and providing a fast seal in bleeding sites is vital to fatal hemorrhage control. Herein, hydrophilic chitosan fibrous mats (CECS-D mats) are fabricated by introducing hydrophilic carboxyethyl groups and subsequent catechol groups onto chitosan fibers. Due to strong hydrophilicity, CECS-D mats exhibit rapid liquid-absorption capacity, especially instantaneous absorptivity to the rabbit blood, which can achieve erythrocyte and platelet aggregations quickly by concentrating blood, thus promoting the formation of blood clots. Furthermore, the mats are self-oxidated to form quinone-amine adducts or quinone multimers by adjusting pH conditions, which not only provides tissue adhesion but also induces erythrocyte aggregation and platelet adhesion, further enhancing the seal and triggering quick closure to achieve fast hemostasis. Therefore, the mats reveal superior hemostatic performance in rabbit liver and spleen models over CECS mats and gauze. Especially in the fatal femoral artery injury model of rabbits, the mats reduce the blood loss by ∼75% and shortened the bleeding time by ∼50% compared with CECS mats, which have been reported to have the same hemostatic effect as commercialized Celox products in a swine femoral artery injury model. Besides, the mats are cytocompatible and degradable as well as antibacterial. This chitosan mat is a promising hemostatic material for fatal hemorrhage control.

Poor Below Knee Runoff Impacts Femoropopliteal Stent Failure and Fluoropolymer Antithrombotic Effect in Healthy Swine Model

Poor below knee (BTK) runoff is a predictor of stent failure after endovascular femoropopliteal artery treatment; however, lack of pathological evaluation has prevented characterisation of stent failure. The study aimed to investigate the impact of poor BTK runoff and the antithrombotic effect of the polymer of fluoropolymer coated paclitaxel eluting stents (FP-PESs) in a healthy swine femoropopliteal artery model. FP-PESs and bare metal stents (BMSs) and FP-PES and polymer free paclitaxel coated stents (PF-PCSs) were implanted in the bilateral femoral arteries of healthy swine (n= 6, respectively) following coil embolisation in both tibial arteries to induce poor BTK runoff. Histological assessment and intravascular imaging device evaluation were performed at one month. The Japanese Association for Laboratory Animal Science approved the study protocol (reference number: IVT22-90). Optical coherence tomography showed significantly lower percent area stenosis in FP-PES compared with BMS (37.3%, [interquartile range (IQR), 25.6-54.3] % vs. 92.5%[IQR, 75.5 - 96.1] %, respectively, p= .031), and PF-PCS (8.3%[IQR, 4.5 - 27.0] % vs. 31.2%[IQR, 23.3 - 52.2] %, respectively, p= .031). Histopathological evaluation demonstrated that thin fibrin attachment without re-stenosis was the most dominant neointimal tissue characteristic in FP-PES. On the other hand, neointimal tissue characteristics with significant restenosis of BMS and PF-PCS were mainly organising or organised thrombus. Organising and or organised thrombus attachment due to poor BTK runoff was the main cause of in stent restenosis of the swine femoral artery. FP-PES demonstrated the least percent area stenosis, suggesting the importance of the antithrombotic effect of polymer.

Novel cross-linked polysaccharide-polyelectrolyte hemostatic foam improves survival compared to CombatGauze in swine femoral artery hemorrhage model.

Uncontrolled hemorrhage is the leading cause of preventable death in combat and civilian trauma. Efficacious hemostatic agents in junctional hemorrhage can quell blood loss and improve survival. We hypothesized that a novel hemostatic foam of starch and chitosan would improve hemostasis, and thereby increase survival in a swine femoral artery hemorrhage model when compared to CombatGauze. A novel hemostatic foam of starch and chitosan was created and modified over the study period. 30 pigs (4 excluded) were assigned to treatment using either foam version 1 (FV1, n = 9) or 2 (FV2, n = 8), or CombatGauze (CG, n = 9) in a standard swine femoral artery hemorrhage model. Animals were observed for 150 minutes. Outcomes assessed included hemostasis, survival, post-treatment blood loss, IV fluid volume, and hemodynamic and laboratory trends. Hemostasis prior to 150 minutes was similar with 44.4%, 77.8%, and 50% of swine treated with CG, FV1 and FV2, respectively (Kaplan-Meyer and log-rank test [KM-LR] p > 0.05). Survival to 150 minutes was improved in swine treated with FV1 (100%) compared to CG (55.6%) (KM-LR p = 0.02). Survival was similar between FV1 and FV2 (75%) (KM-LR p > 0.05), and between CG and FV2 (KM-LR p > 0.05). Using mixed model for longitudinal data, MAP decreased significantly in CG- and FV2-treated swine, while there was no significant change in MAP in FV1-treated swine. Trends in lactic acid, hematocrit, platelets, INR, and TEG were more favorable for FV1 compared to CG. In this preclinical study of junctional hemorrhage, survival was improved in swine treated with version 1 of a novel chitosan/starch foam compared to CombatGauze. Trends in hemodynamics and laboratory data were also more favorable in the FV1-treated swine. This novel hemostatic foam may be an effective alternative to current hemostatic agents. not applicableStudy type: Original research: animal research.

Bioabsorbable Fibrillar Gauze Dressing Based on N-Carboxyethyl Chitosan Gelling Fibers for Fatal Hemorrhage Control.

Death from lethal hemorrhage remains a major problem in various emergency scenarios. There is a continuous interest in the development of absorbable hemostatic dressings that can control hemorrhage rapidly and can be left in the wound site without removal. In this study, we report a hemostatic gauze dressing based on N-carboxyethyl chitosan (CECS) gelling fibers. The CECS fibrillar gauze combines ultra-hydrophilic, cationic chemical property of the fiber components with the fluffy nonwoven material form, exhibiting good conformability for wound filling, high fluid uptaking capacity, and enhanced blood-concentrating effect. In a swine femoral artery injury model, the CECS fibrillar gauze achieves shorter time to hemostasis and less blood loss compared with commercially available hemostatic dressings. This chitosan gelling fiber gauze demonstrates comparable bioabsorbability to clinically used absorbable hemostat and thus may be applied to treat fatal hemorrhage both in emergency medical services and in internal surgical procedures.

Injectable zein gel with in situ self-assembly as hemostatic material

Zein is a biocompatible and biodegradable corn protein with promising properties for biomedical applications. It is hydrophobic with the ability to self-assemble in an aqueous medium. It can also form a gel in hydroalcoholic solvents at higher concentrations. Few studies have investigated the biomedical significance of zein gels. Herein, we exploited the injectability and water-responsive increase in stiffness of zein gel to achieve hemostasis by physical blockage of the wound and clot formation. The release of components from the gel further aided blood clotting and gave a higher clot strength than a natural clot, which can prevent rebleeding. Rabbit aortic injury and swine femoral artery injury models were used to evaluate the hemostatic efficacy of the zein gel. Zein gel was effective in both hemostatic models without applying external compression due to an in situ increase in stiffness, while the control (Celox™ Gauze) required external compression at the wound site. The zein gel was easily removed after hemostasis due to hydrophobic self-assembly. Overall, zein gel is proposed as an effective hemostatic product for any wound shape owing to its good shape adaptability and rapid in situ blood-responsive stiffness increase.

Cellulose fibers-reinforced self-expanding porous composite with multiple hemostatic efficacy and shape adaptability for uncontrollable massive hemorrhage treatment

Uncontrollable hemorrhage leads to high mortality and thus effective bleeding control becomes increasingly important in the military field and civilian trauma arena. However, current hemostats not only present limitation when treating major bleeding, but also have various side effects. Here we report a self-expanding porous composites (CMCP) based on novel carboxymethyl cellulose (CMC) fibers and acetalized polyvinyl alcohol (PVA) for lethal hemorrhage control. The CMC fibers with uniform fibrous structure, high liquid absorption and procoagulant ability, are evenly interspersed inside the composite matrix. The obtained composites possess unique fiber-porous network, excellent absorption capacity, fast liquid-triggered self-expanding ability and robust fatigue resistance, and their physicochemical performance can be fine-tuned through varying the CMC content. In vitro tests show that the porous composite exhibits strong blood clotting ability, high adhesion to blood cells and protein, and the ability to activate platelet and the coagulation system. In vivo hemostatic evaluation further confirms that the CMCP presents high hemostatic efficacy and multiple hemostatic effects in swine femoral artery major hemorrhage model. Additionally, the CMCP will not fall off from the injury site, and is also easy to surgically remove from the wound cavity after the hemostasis. Importantly, results of CT tomography and 3D reconstruction indicate that CMCP can achieve shape adaptation to the surrounding tissues and the wound cavities with different depths and shapes, to accelerate hemostasis while protecting wound tissue and preventing infection.

Fabrication of an expandable keratin sponge for improved hemostasis in a penetrating trauma

Effective hemostasis improvements for penetrating traumas remain a research priority for civilian and noncivilian applications. Herein, we fabricated an expandable keratin sponge (EKS) for the hemostatic treatment of a penetrating trauma based on the excellent hemostatic ability of keratin and the expandable property of polyacrylamide (PAM). EKSs with semi-interpenetrating networks were fabricated by radical polymerization of keratin and PAM, and the EKS showed rapid expansion upon blood absorption. This sponge exhibited effective hemostasis on a rat penetrating liver hemorrhage, and the expansion of the EKS was dependent on the bleeding volume. In addition, the results of a shear wave elastography analysis showed that the elasticity of the liver tissue increased from 12.5 kPa to 21.2 kPa after the penetrating liver trauma treated by the EKS, and the mechanical strength of the liver tissue was maintained after 1 h of the EKS application. Further in vivo tests indicated the effectiveness of the EKS for hemostasis in a swine femoral artery transection hemorrhage model. This EKS is promising for hemostatic applications.

CRT-300.19 Evaluation of Safety and Efficacy of Ranger Paclitaxel-Coated Balloon in a Swine Femoral Artery Model

Drug-coated balloon (DCB) have emerged as a therapeutic alternative in the treatment of peripheral vascular disease. The aim of this study was designed to evaluate the safety and efficacy of a Ranger DCB in a swine femoral artery model. The femoral arteries of 42 swine were treated with low

Randomized controlled trial comparing dynamic simulation with static simulation in trauma.

Current general surgery residents have limited exposure to open trauma operative cases. Simulation supplements variable rotation volume and provides experience with critical but rarely performed procedures. Open simulation classically focuses on static models with anatomic accuracy but lacks practicality when hemorrhage control is the lifesaving maneuver. We sought to evaluate whether training on a dynamic simulator, while much less expensive than training on a static cadaver, might be at least as effective in training surgery residents to expeditiously place temporary vascular shunts (TVSs). Our research team developed an inexpensive, reusable dynamic simulator with ongoing hemorrhage to instruct trainees in the steps of TVS placement. We enrolled 54 general surgery residents in a noninferiority randomized controlled trial comparing training of TVS placement on the dynamic simulator (n = 28) versus a cadaver arm (n = 26). After standardized video didactics, trainees practiced on either the simulator or cadaver arm. After the trainees achieved competency, they were tested on placing a TVS for a live swine femoral artery injury. Two blinded trauma surgeons evaluated the recorded performances. Residents did not differ in baseline characteristics between groups, and all residents in both groups successfully completed the TVS placement test. Subjects trained on the simulator placed the TVS faster than those trained on a cadaver (584 seconds vs. 751 seconds; difference, +167 seconds faster; 90% confidence interval [CI], +52 to +282 seconds), with a trend toward faster time to hemorrhage control (110 seconds vs. 148 seconds; difference, +38 seconds faster; 90% CI, -8 to +84). There was no significant difference in Objective Structured Assessment of Technical Skills scores (3.72 vs. 3.44; difference, +0.27 units better; 90% CI, -0.04 to +0.59). Training on a dynamic simulator resulted in noninferior time to completion of vascular shunt placement compared with training on a cadaver. The addition of dynamic hemorrhage to simulators might inexpensively augment trauma skills training.

Evaluation of Hemostatic Effects of Carbonized Hair-Loaded Poly(L-Lactic) Acid Nanofabrics.

Carbonized human hair is used to stop bleeding in traditional Chinese medicine. The present study was aimed to prepare a novel nanofiber containing carbonized human hair and evaluate its hemostatic effect. Carbonized human hair-loaded poly(L-lactic) acid nanofiber was prepared by electrospinning. The hemostatic efficacies of dressings composed of either carbonized human hair, carbonized human hair-loaded poly(L-lactic) acid nanofiber, Yunnan White Drug power or poly(L-lactic) acid nanofiber were investigated in several swine arterial and venous bleeding models. Blood loss and bleeding time were measured. In vitro, carbonized human hair, carbonized human hair-loaded nanofiber and Yunnan White Drug Powder significantly shortened the clotting time in comparison with the nanofiber control group. The hemostatic effects of the carbonized human hair-load nanofiber on liver and spleen traumatic wounds were better than those of carbonized human hair and Yunnan White Drug Powder in terms of blood loss and bleeding time. Similar effects were observed in swine femoral artery wound model. In the swine femoral vein wound model, bleeding could not be stopped in the control animals. In the carbonized human hair group, Yunnan White Drug Powder group and carbonized human hair-load nanofiber group, bleeding was stopped in 83.3%, 83.3% and 100% of the animals, respectively. In conclusion, dressing using carbonized human hair-load nanofibers is effective in controlling severe, uncontrolled bleeding. This dressing may offer a cheap alternative to dressings composed of coagulation proteins.

Enhanced accumulation of LDLs within the venous graft wall induced by elevated filtration rate may account for its accelerated atherogenesis

ObjectiveTo test the hypothesis that the venous graft when implanted in an arterial bypass might endure a significantly elevated water filtration rate, leading to fast infiltration/accumulation of low-density lipoproteins (LDLs) within the graft wall and hence the accelerated atherogenesis. MethodsWe measured filtration rates of the swine femoral artery and lateral saphenous vein under venous and arterial hemodynamic conditions in vitro. Based on the measured filtration rates, we numerically simulated LDL transport in an arterial bypass model with a venous graft. Moreover, in order to validate the theoretical prediction, we measured DiI-LDLs uptake by both arteries and veins under arterial condition. ResultsThe experimental results showed that when subjected to arterial hemodynamic condition, the filtration rate of the venous wall was increased sharply, and significantly higher than that of the artery. Moreover, different from the hydraulic conductivity of artery, the venous one would increase with increasing pressure. The numerical results showed that for the venous graft, both luminal surface LDL concentration and LDL accumulation within the vessel wall were significantly higher than those for the host artery. In addition, the experiment, which was used to confirm theoretical prediction, showed that the amount of DiI-LDLs uptake by the venous wall was much higher compared with arterial wall. ConclusionThe present study suggests that the accelerated atherogenesis of the venous graft is attributable to its elevated filtration rate that may lead to both aggravated concentration polarization of LDLs and enhanced convective transport of LDLs into the graft wall.

Vascular, downstream, and pharmacokinetic responses to treatment with a low dose drug‐coated balloon in a swine femoral artery model

This study was designed to evaluate the safety of a novel drug-coated balloon (DCB) with 2 µg/mm(2) paclitaxel and a carrier comprised of polysorbate and sorbitol in a swine femoral artery model. DCB have emerged as a therapeutic alternative in the treatment of peripheral vascular disease. The femoral arteries of 45 swine were treated with low pressure balloon inflation either 1× clinical dose (single inflation, 2 µg/mm(2) paclitaxel) or 4× dose (2 DCBs, each with 4 µg/mm(2) paclitaxel) or control (uncoated) balloons. The treated arteries, downstream vascular beds, and organs were assessed histologically at 28, 90, and 180-days. Twenty-four swine were treated with 1× dose for pharmacokinetic analysis through 30 days. Arterial tissue paclitaxel concentration was 58.8 ± 54.2 ng/mg at 1-hr and 0.3 ± 0.4 ng/mg at 30 days, whereas plasma paclitaxel could no longer be detected after 1 day. The treated arteries displayed minimal endothelial loss, fibrin deposition, and inflammation with long-term dose-dependent drug effect (medial smooth muscle cell loss) peaking at 90 days for both 1× (1.1 ± 1.4 vs. 0.0 ± 0.0, P = 0.008) and 4× dose (2.0 ± 1.5 vs. 0.0 ± 0.0, P < 0.001). In parallel, healing of the treated arteries was evident by significantly greater medial proteoglycan and collagen deposition at 180 days. No evidence of ischemia from downstream emboli or systemic toxicity was observed even for 4× DCB groups. The findings indicate desired pharmacologic levels with biologic effects at early and healing at late time points in the treated arteries, without evidence of significant downstream emboli or systemic toxicity, consistent with safety of the Lutonix DCB.

A Novel Swine Model to Evaluate Arterial Vessel Injury after Mechanical Endovascular Thrombectomy

Few animal models have been reported to evaluate and compare mechanical endovascular thrombectomy (MET) devices used to treat human ischemic stroke. These models may contribute to the understanding of arterial injury induced by a MET device and potentially by extrapolation to human intracranial arteries. We have developed a novel swine model for MET that allows visualization of the thrombus/device interaction and characterization of mechanical impact on the vessel wall. Twenty superficial femoral arteries were occluded with radiopaque thrombus, and 20 without thrombus were treated with thrombectomy devices. Acute histopathological changes were evaluated. The swine femoral artery, which is comparable in size to the human middle cerebral artery or basilar artery, may offer a useful animal model for the study of histologic alterations induced by MET.

A Salmon Thrombin-Fibrinogen Dressing Controls Hemorrhage in a Swine Model Compared to Standard Kaolin-Coated Gauze

Battlefield hemorrhage remains the primary cause of death in potentially survivable combat injuries with noncompressible hemorrhage. Fibrin dressings have great potential for reducing mortality, however are limited by cost, availability, and disease transmission.Dressings comprising a soluble dextran dressing with lyophilized salmon thrombin and fibrinogen (STF) were tested against Combat Gauze (CG) as a control in a standard swine femoral artery hemorrhage model. Ten female swine were used in each arm of the study.Survival, blood loss, and time to hemostasis were similar between the two dressings. Two of the CGtreated animals that survived exsanguinated during the simulated walking maneuver. Three CG-treated animals formed a clot within the wound, but the clot did not adhere to the femoral artery injury. All ten of the STF-treated animals formed a clot in the wound that adhered and sealed the arterial injury site, even in three animals that did not survive. None of the STF-treated animals bled following the simulated walking maneuver. Three of five STF-treated animals reestablished blood flow distal to the injury as demonstrated by angiography.The STF dressing is as efficacious as CG in treating hemorrhage in this model of a lethal injury. Further, the STF dressing formed a fibrin sealant over the injury, whereas CG achieved hemostasis by occlusive compression of the artery. The sealant property of the STF dressing allowed reestablishment of antegrade blood flow into the distal limb, demonstrating that this dressing has the potential of limb salvage in addition to control of life-threatening hemorrhage.

High Range Resolution Ultrasonographic Vascular Imaging Using Frequency Domain Interferometry With the Capon Method

For high range resolution ultrasonographic vascular imaging, we apply frequency domain interferometry with the Capon method to a single frame of in-phase and quadrature (IQ) data acquired using a commercial ultrasonographic device with a 7.5 MHz linear array probe. In order to tailor the adaptive beam forming algorithm for ultrasonography we employ four techniques: frequency averaging, whitening, radio-frequency data oversampling, and the moving average. The proposed method had a range resolution of 0.05 mm in an ideal condition, and experimentally detected the boundary couple 0.17 mm apart, where the boundary couple was indistinguishable from a single boundary utilizing a B-mode image. Further, this algorithm could depict a swine femoral artery with a range beam width of 0.054 mm and an estimation error for the vessel wall thickness of 0.009 mm, whereas using a conventional method the range beam width and estimation error were 0.182 and 0.021 mm, respectively. The proposed method requires 7.7 s on a mobile PC with a single CPU for a 1×3 cm region of interest. These findings indicate the potential of the proposed method for the improvement of range resolution in ultrasonography without deterioration in temporal resolution, resulting in enhanced detection of vessel stenosis.

Development of a Standard Swine Hemorrhage Model for Efficacy Assessment of Topical Hemostatic Agents

The diverse information of efficacy of hemostatic products, obtained from different military laboratories using different models, has made it difficult to ascertain the true benefit of new hemostatic agents in military medicine. The aim of this study was to recommend a standard hemorrhage model for efficacy testing acceptable by most investigators in the field and avoid contradictory and duplicative efforts by different laboratories. The swine femoral artery injury model (6-mm arteriotomy) with some modifications was tested to standardize the model. The suggested modifications included no splenectomy, one-time treatment, 30 seconds free bleeding, and 5 L limit for fluid resuscitation. The model was tested with all or some of these modifications in four experimental conditions (n = 5-6 pigs per condition) using Combat Gauze (CG) as control agent. The primary end points including blood pressure, blood loss, and survival rates were modestly changed in the four conditions. The second experimental condition in which bleeding was treated with a single CG with 3-minute compression produced the most suitable results. The average blood loss was 99 mL/kg, and hemostasis was achieved in one-third of the pigs, which led to matching survival rate. A rigorous hemorrhage model was developed for future evaluation of new hemostatic agents and comparison with CG, the current standard of care. This model may not be suitable for testing every agent and some modifications may be necessary for specific applications. Furthermore, laboratory studies using this or similar models must be accompanied by operational testing in the field to confirm the efficacy and practical utility of selected agents when used on the battlefield.

Preliminary Study of the Effects of Smectite Granules (WoundStat) on Vascular Repair and Wound Healing in a Swine Survival Model

WoundStat (WS) (TraumaCure, Bethesda, MD) is a topical hemostatic agent that effectively stops severe hemorrhage in animal models. To the best of our knowledge, no survival study has been conducted to ensure long-term product safety. We evaluated vascular patency and tissue responses to WS in a swine femoral artery injury model with survival up to 5 weeks. Anesthetized swine received a standardized femoral artery injury with free hemorrhage for 45 seconds followed by WS application. One hour after application, the WS was removed, the wound copiously irrigated, and the artery repaired using a vein patch. Six groups of three animals received WS and were killed either immediately after surgery or at weekly intervals up to 5 weeks. Three control animals were treated with gauze packing and direct pressure followed by identical vascular repair and survival for 1 week. At the time of killing, angiograms were performed, and tissue was collected for histopathology. Hemostasis was complete in all WS animals. All animals survived the procedure, and there were no clinically evident postoperative complications. Vascular repairs were angiographically patent in 15 of 18 animals (83%) receiving WS. Histopathologic examination of WS animals revealed severe diffuse fibrogranulomatous inflammation, early endothelial degeneration with subsequent intimal hyperplasia, moderate myocyte necrosis, and fibrogranulomatous nerve entrapment with axonal degeneration. Although an effective hemostatic agent, WS use was associated with a substantial local inflammatory response and neurovascular changes up to 5 weeks postinjury.

Addition of a propyl gallate-based procoagulant to a fibrin bandage improves hemostatic performance in a swine arterial bleeding model

Fibrin bandages manufactured by Nycomed Austria (TC-S) were modified by the addition of Hemostyptin (HS), a proprietary platelet-activating reagent containing propyl gallate. HS was added as an additional layer to TC-S fibrin bandages and the bandages were tested for hemostatic efficacy in a swine femoral artery bleeding model. Injuries were treated with a TC-S+HS bandage preparation using HS lyophilized onto a bandage surface that was then attached to the fibrin dressing. This preparation qualitatively and quantitatively exhibited more robust blood clotting at the surgical site than the control bandages. TC-S+HS bandages were more effective than control bandages with a difference in blood loss of 251.8±66.5 g for TC-S bandage alone, n=12 vs. 121±40.7 g, n=13 for the TC-S+HS bandage, P=0.05. Bleeding times were shortened for animals treated with the HS fortified bandages and residual platelets counts in these animals were higher.

ε-Amino caproic acid additive decreases fibrin bandage performance in a swine arterial bleeding model

ε-Amino caproic acid (EACA), a lysine analog that inhibits the activity of plasmin, was added to Nycomed (TC-S) fibrin bandages, and the bandages were tested for hemostatic efficacy in a swine femoral artery bleeding model. The blood loss using the bandage with EACA (TC-S+EACA; 728.8±132 g, n=5) was much greater as compared to the TC-S bandage alone (TC-S; 237.8±47.9 g, n=6, p=.02). The time to “cessation of bleeding” ( T b) was also increased for animals treated with TC-S+EACA bandages compared to the TC-S controls (33.6±10.8 min vs. 9.2±2.2 min; p=.05). Although plasma fibrinogen concentration decreased in animals treated with the TC-S+EACA bandage, activated partial thromboplastin times (aPTT) and thrombin times (TT) were decreased. Animals treated with the TC-S control bandage exhibited no changes in fibrinogen, aPTT or TT. Prothrombin times (PT) were unchanged in either group. In conclusion, addition of EACA to the Nycomed product decreased fibrin bandage efficiency.

Evaluation of annexin V as a platelet-directed thrombus targeting agent

Annexin V is a human phospholipid binding protein (M r 36,000) that binds with high affinity to activated platelets in vitro. We studied the biodistribution and thrombus binding of annexin V in rabbit and swine models of fully occlusive arterial thrombi formed 1–2 h prior to injection of annexin V. Iodinated annexin V was cleared from blood in a rapid early phase ( t 1 2 = 6.4 min, 76% of radioactivity) and a slower late phase ( t 1 2 = 71 min, 24% of radioactivity). Organ uptake was highest in the kidney and spleen and lowest in heart and skeletal muscle. Thrombus/blood uptake ratios were (mean ± SEM): 6.39 ± 1.80 for rabbit iliac artery, 6.97 ± 1.45 for swine carotid artery, and 7.68 ± 1.70 for swine femoral artery (all p values < 0.01 versus control artery); a control protein, ovalbumin, showed an uptake ratio of 0.59 ± 0.08 in swine femoral artery thrombi. These results indicate that annexin V is useful as an agent for selective targeting of platelet-containing thrombi.