Kevin M. Lewis

Efficacy of hemostatic matrix and microporous polysaccharide hemospheres

BACKGROUND Microporous Polysaccharide Hemospheres (MPH) are a new plant-derived polysaccharide powder hemostat. Previous studies investigated MPH as a replacement to nonflowable hemostatic agents of different application techniques (e.g., oxidized cellulose, collagen); therefore, the purpose of this study was to determine if MPH is a surrogate for flowable hemostatic agents of similar handling and application techniques, specifically a flowable thrombin-gelatin hemostatic matrix. METHODS Hemostatic efficacy was compared using a heparinized porcine abrasion model mimicking a capsular tear of a parenchymal organ. MPH (ARISTA, 1 g) and hemostatic matrix (Floseal, 1 mL) were applied, according to a randomized scheme, to paired hepatic abrasions (40 lesions per group). Hemostatic success, control of bleeding, and blood loss were assessed 2, 5, and 10 min after treatment. Hemostatic success and control of bleeding were analyzed using odds ratios and blood loss using mean differences. RESULTS Hemostatic matrix provided superior hemostatic success relative to MPH at 5 (odds ratio: 0.035, 95% confidence interval: 0.004-0.278) and 10 min (0.032, 0.007-0.150), provided superior control of bleeding at 5 (0.006, <0.001-0.037) and 10 min (0.009, 0.001-0.051), and had significantly less blood loss at 5 (mean difference: 0.3118 mL/min, 95% confidence interval: 0.0939-0.5296) and 10 min (0.5025, 0.2489-0.7561). CONCLUSIONS These findings corroborate other MPH investigations regarding its low-level efficacy and suggest that MPH is not an appropriate surrogate for hemostatic matrix despite similar application techniques. The lack of a procoagulant within MPH may likely be the reason for its lower efficacy and need for multiple applications.

Swelling, sealing, and hemostatic ability of a novel biomaterial: A polyethylene glycol-coated collagen pad

Trends in the development of hemostatic agents are towards self-adhering pads. This study investigates a novel biomaterial made of a polyethylene glycol-coated collagen pad (PCC). The swelling and adherence of PCC were investigated in vitro, and the hemostatic and sealing ability was investigated in vivo. In vitro, the maximum swell of PCC submerged in human plasma for 24 h is 65%. The greatest swell was in thickness, averaging 24% to a mean thickness of 2.5 ± 0.19 mm (mean±SD) (N = 20). PCC withstood clinically relevant pressures when applied to a collagen casing washed with bile, lymph, urine, saline, and cerebrospinal fluid mixed at 33% and 67% with blood. In vivo, PCC provided complete hemostasis when applied to severe, arterial bleeds of actively ventilated pulmonary parenchyma at 3, 5, 8, and 10 min after application in a heparinized porcine pulmonary segmentectomy model. The mean rate of bleeding was 17.7 ± 8.6 ml/min. The lungs were ventilated at 15 ± 4 breaths per min and an airway pressure of 19 ± 2 cm H2O. PCC had no incidence of hematoma and an 11% incidence of intraoperative air leak (N = 36). These data are promising for future clinical application of a new versatile, self-adhering hemostatic sealing pad consisting of a polyethylene glycol-coated collagen.

Hemostatic efficacy of a novel, PEG-coated collagen pad in clinically relevant animal models

PURPOSE Currently available hemostatic pads are effective in treating oozing bleeds, but otherwise ineffective in more severe bleeding. This study investigates the hemostatic efficacy of a new hemostatic pad with advanced sealing properties using protein-reactive polyethylene glycol-coated collagen (PCC, Hemopatch) versus an oxidized regenerated cellulose (ORC, Tabotamp/Surgicel Original) in a leporine arterial bleeding model of vascular reconstruction and a porcine hepatic model of general surgery. METHODS In both models, paired lesions were created and treated according to a randomized scheme and evaluated up to 10 min after application (40 lesions/group/model). Arterial needle holes were created in the femoral arteries of anesthetized rabbits and hepatic lesions were created into hepatic parenchyma of anesthetized pigs. Both models were heparinized to mimic clinical comorbidity. RESULTS In the leporine vascular surgical model, PCC provided superior hemostatic success compared to ORC at 2 min (Odds Ratio of Success: 85, 95% CI: 25.8-282) and similar hemostatic success at 10 min. In the porcine hepatic model, PCC provided superior hemostatic success compared to ORC at 2 (98 vs 55%, P < 0.001), 3 (93 vs 65%, P < 0.001), 4 (98 vs 68%, P < 0.001) and 5 min (95 vs 80%, P < 0.001), but similar hemostatic success at 8 and 10 min. DISCUSSION PCC provided 75.4% greater hemostatic success at 2 min in the arterial model and was at least 100 times more likely to be hemostat effective at 2 min in the hepatic model than ORC. CONCLUSIONS PCC provided faster hemostasis than ORC in a vascular and hepatic surgical model with impaired coagulation.

Two-component polyethylene glycol surgical sealant influence on intraperitoneal infection in a refined rodent model

OBJECTIVE This study determined the influence of a 2-component polyethylene glycol surgical sealant (Coseal) as an adhesion prevention device on sepsis-related mortality and/or systemic bacterial translocation to the spleen. STUDY DESIGN A bacterial inoculum and telemetry probe were implanted in 50 treated and 49 untreated rats. Telemetry probes monitored core-body temperature to determine time of death. Spleens were collected on day 3 for quantitative bacteriology of Escherichia coli and Bacteroides fragilis. RESULTS Median survival time and mortality of treated rats (37.0 hours, 54.0%) were noninferior to untreated rats (47.5 hours, 55.1%). Median E coli titers in treated rats (2.24 log colony forming units/spleen) were significantly less than untreated rats (4.32 log colony forming units/spleen). B fragilis titers were not different. CONCLUSION This study demonstrates intraperitoneal administration of a 2-component polyethylene glycol surgical sealant as an adhesion prevention device does not alter time to death or sepsis-related mortality and/or systemic bacterial translocation to the spleen.

Randomized, Controlled Comparison of Advanced Hemostatic Pads in Hepatic Surgical Models

Blood loss during hepatic surgery leads to poor patient outcomes. This study investigates the hemostatic efficacy of a novel sealing hemostatic pad (polyethylene glycol-coated collagen, PCC) and a fibrin sealant pad (fibrin-thrombin coated collagen, FTC) in a leporine hepatic segmentectomy and a porcine hepatic abrasion model. A segmentectomy was used to compare hemostatic success and hematoma incidence in 20 rabbits (10/group). Hepatic abrasions were used to compare hemostatic success up to 10 min after application in six pigs (42 lesions/group). In the segmentectomy model, PCC achieved 100% hemostatic success within 2 min (95% CI: 72.3% to 100%) and FTC achieved 80% hemostatic success within 3 min (49.0% to 94.3%). PCC had lower hematoma incidence at 15 min (0.0 versus 11.1%) and 24 h (20.0 versus 66.7%). In the abrasion model, PCC provided superior hemostatic success at 3 (odds ratio: 24.8, 95% CI: 8.86 to 69.2, P < 0.001), 5 (66.3, 28.5 to 153.9, P < 0.001), 7 (177.5, 64.4 to 489.1, P < 0.001), and 10 min (777.6, 148.2 to 4078, P < 0.001) leading to statistically significant less blood loss. The novel sealing hemostat provides faster and more sustained hemostasis than a fibrin sealant pad in a leporine hepatic segmentectomy and a porcine hepatic abrasion model of hepatic surgery.

Development and validation of an intraoperative bleeding severity scale for use in clinical studies of hemostatic agents

Background. Clinical studies investigating topical hemostatic agents have not used standardized definitions for intraoperative bleeding. The Food and Drug Administration has recently sought use of a validated, clinician‐reported scale to standardized bleeding sites in these clinical studies. The intent of a scale is to reduce patient risk, generate labeling claims, and allow comparisons among study results. We describe the development and validation of an intraoperative bleeding severity scale. Methods. A concept phase defined the framework of the scale. A feasibility and validation phase investigated the usability, clarity, relevance, and reliability (ie, intra‐ and interobserver concordance) among surgeons and surgical specialties as required by the Food and Drug Administration for the validation of a clinician‐reported scale. Data were collected using an online tool. A total of 144 surgeons participated in the 3 phases. Results. The scale developed during the concept phase achieved an average intraobserver concordance of 0.97 and an interobserver concordance of 0.89 in the feasibility phase (N = 33); a concordance of 1.0 is perfect. The scale was refined and then achieved an average intraobserver concordance of 0.98 and an interobserver concordance of 0.91 in the validation phase with unanimous agreement by surgeons from multiple surgical specialties that the scale can be implemented into clinical studies (N = 102). Conclusion. This study validated an intraoperative bleeding severity scale for use in clinical studies investigating hemostatic agents. The scale was usable, clear, and clinically relevant with excellent reliability. The scale fulfills requirements of the Food and Drug Administration for a clinician‐reported scale and can be used to generate clinically meaningful labeling claims.

Treatment of Severe Aortic Bleeding Using Hemopatch in Swine on Dual Antiplatelet Therapy

ABSTRACT Purpose: The perioperative management of patients on antithrombotic therapy is currently an unresolved problem as these therapies pose a considerable risk for perioperative hemorrhagic complications. The presented studies investigated the efficacy of a new collagen technology to achieve hemostasis. A polyethylene glycol-coated collagen pad (PCC) was compared to a marketed fibrinogen-thrombin coated collagen pad (FTC) for the treatment of an aortotomy incision in heparinized swine on dual antiplatelet therapy. Materials and Methods: Twenty-eight 3-mm aortotomy incisions were created in nine heparinized pigs without antiplatelet therapy and treated with PCC. Sixty-eight aortotomy incisions were created in ten heparinized pigs that received clopidogrel (10–11 mg/kg) and acetylsalicylic acid (8–11 mg/kg) orally for 5 days, and treated with either PCC or FTC (N = 34/group). Dual antiplatelet therapy resulted in significantly reduced platelet function. Aortotomy incisions resulted in life-threatening bleeding of 35–292 ml/min. Results: In animals without antiplatelet treatment, PCC provided 96% immediate hemostatic success. In animals with antiplatelet treatment, FTC provided 18% immediate hemostatic success increasing to 74% after 10 min. Strikingly, PCC provided 94% immediate success increasing to 100% after 10 min. Controlling for differences in pretreatment bleeding rates, statistical model-estimated time to hemostasis was 12 times shorter in PCC-treated lesions (p < .02). Conclusion: The combination of a procoagulant collagen pad with a synthetic sealing component provides excellent hemostatic properties under a worst-case scenario. PCC rapidly and firmly adheres to tissue, thereby controlling severe arterial bleeding, even when platelet function is significantly reduced. Treatment with PCC provided superior time to hemostasis compared to FTC.

Control of bleeding in surgical procedures: critical appraisal of HEMOPATCH (Sealing Hemostat)

The need for advanced hemostatic agents increases with the complexity of surgical procedures and use of anticoagulation and antiplatelet treatments. HEMOPATCH (Sealing Hemostat) is a novel, advanced hemostatic pad that is composed of a synthetic, protein-reactive monomer and a collagen backing. The active side is covered with a protein-reactive monomer: N-hydroxysuccinimide functionalized polyethylene glycol (NHS-PEG). NHS-PEG rapidly affixes the collagen pad to tissue to promote and maintain hemostasis. The combined action of the NHS-PEG and collagen is demonstrated to have benefit relative to other hemostatic agents in surgery and preclinical surgical models. This paper reviews the published investigations and case reports of the hemostatic efficacy of HEMOPATCH, wherein HEMOPATCH is demonstrated to be an effective, easy-to-use hemostatic agent in open and minimally invasive surgery of patients with thrombin- or platelet-induced coagulopathies.

Safety and Efficacy of a Novel, Self-Adhering Dural Substitute in a Canine Supratentorial Durotomy Model

Abstract BACKGROUND Cerebrospinal fluid (CSF) leaks increase postoperative risk for complication, likelihood of reoperation, and costs. OBJECTIVE To investigate a novel, self-adhering polyethylene glycol-coated collagen pad (PCC) as a dural substitute relative to Duragen XS (DGX; Integra LifeSciences Corporation, Plainsboro, New Jersey) and as a dural sealant relative to Tachosil (Takeda Austria GmbH, Linz, Austria), a fibrinogen and thrombin-coated collagen pad (FTC). METHODS A canine supratentorial durotomy surgical model was used to investigate the safety and efficacy of PCC. For safety, 4 animals were bilaterally treated with DGX or PCC and recovered for 1, 8, or 16 wk; total 24 animals. Each animal underwent physical and neurological examinations weekly and 16-wk animals underwent a magnetic resonance imaging (MRI) examination at each time point. For efficacy, 9 animals were unilaterally treated with FTC or PCC and underwent a burst pressure test intraoperatively or 14 d postoperatively; total 36 animals. RESULTS In the safety study, no abnormal clinical signs or changes were noted on physical and neurological examinations, or in clinical pathology, CSF analysis or histopathology of DGX or PCC-treated animals. No consistent signs of cerebral compression, CSF leak, hemorrhage, or hydrocephalus were noted on MRI. In the efficacy study, no significant difference was found between FTC and PCC at each time point or overall (13.9 vs 12.3 mm Hg, n = 18 per group, P = .46). CONCLUSION PCC is safe for use as a dural substitute and effective as a dural sealant. The novel, self-adhering combination of a polyethylene glycol-based sealant and a collagen pad may offer unique benefits to the advancement of duraplasty.

Cost-effectiveness analysis of a sealing hemostat patch (HEMOPATCH) vs standard of care in cardiac surgery

Abstract Background: A recent randomized controlled trial showed that patients undergoing ascending aorta surgery treated with HEMOPATCH to control bleeding had a significantly better hemostasis success rate than with dry or wet gauze compression or similar standard of care (SOC). Objective: To compare the cost-effectiveness using two different agents for hemostasis (HEMOPATCH vs dry or wet gauze compression or similar SOC) in cardiac surgery from the European hospital perspective. Methods: A literature-based cost-effectiveness model estimating average cost per successful hemostasis event was developed based on the hemostasis efficacy difference (HEMOPATCH = 97.6%, SOC = 65.8%, p < .001). Additional clinically significant end-points studied in the trial (blood transfusions and surgical revisions) were also analyzed. It was assumed that each surgery utilized two units of HEMOPATCH (dimensions of 4.5 × 9 cm) and two units of SOC. Product acquisition costs for HEMOPATCH and SOC were included along with outcome-related costs derived from the literature and inflation-adjusted to 2017 EUR and GBP. Results are presented for an average hospital with an annual case load of 574 cardiac surgeries. One-way and probabilistic sensitivity analyses were performed. Results: Considering only product acquisition cost, HEMOPATCH had an incremental cost-effectiveness ratio (ICER) of €1,659, €1,519, €1,623, and £1,725 per hemostasis success when compared to SOC for Italy, Spain, France, and the UK, respectively. However, when considering the cost and potential difference in the frequency of transfusions and revisions compared to SOC, the use of HEMOPATCH was associated with an annual reduction of six revisions and 60 transfusions, improving the ICER to €1,440, €1,222, €1,461, and £1,592, respectively. Sensitivity analysis demonstrated model robustness. Conclusions: This analysis supports the use of HEMOPATCH over SOC in cardiac surgery in European hospitals to improve hemostasis success rates and potential cost offsets from reduced transfusions, complications, and surgical revisions.