Acquired Factor V Deficiency Associated With Exposure to Bovine Thrombin in a Burn Patient:

Thrombin and Thrombin-Incorporated Biomaterials for Disease Treatments

Thrombin, a coagulation-inducing protease, has long been used in the hemostatic field. During the past decades, many other therapeutic uses of thrombin have been developed. For instance, burn treatment, pseudoaneurysm therapy, wound management, and tumor vascular infarction (or tumor vasculature blockade therapy) can all utilize the unique and powerful function of thrombin. Based on their therapeutic effects, many thrombin-associated products have been certificated by the Food and Drug Administration, including bovine thrombin, human thrombin, recombinant thrombin, fibrin glue, etc. Besides, several thrombin-based drugs are currently undergoing clinical trials. In this article, the therapeutic uses of thrombin (from the initial hemostasis to the latest cancer therapy), the commercially available drugs associated with thrombin, and the pros and cons of thrombin-based therapeutics (e.g., adverse immune responses related to bovine thrombin, thromboinflammation, and vasculogenic "rebounds") are summarized. Further, the current challenges and possible future research directions of thrombin-incorporated biomaterials and therapies are discussed. It is hoped that this review may provide a valuable reference for researchers in this field and help them to design safer and more effective thrombin-based drugs for fighting against various intractable diseases.

Delayed spontaneous remission of acquired factor V inhibitor refractory to immunosuppressive therapy with pregnancy-associated improvement

Introduction: Acquired factor V inhibitor (AFVI) is a rare autoimmune bleeding disorder. The treatment of AFVI is challenging, and patients often require both bleeding control and inhibitor eradication. Methods: We conducted a retrospective analysis of the medical records of a 35-year-old Caucasian woman who presented with severe AFVI-induced bleeding and subsequent immunosuppressive therapy. Results: To provide haemostasis, rFVIIa was given with good efficacy. The patient was treated with various combinations of immunosuppressive regimens over the course of 2.5 years, including plasmapheresis plus immunoglobulins, dexamethasone + rituximab, cyclophosphamide + dexamethasone + rituximab + cyclosporine, cyclosporin + sirolimus + cyclophosphamide + dexamethasone, bortezomib + sirolimus + methylprednisolone, and sirolimus + mycophenolate mofetil. Although these treatment modalities resulted in intermittent partial reversals of AFVI over 2.5 years, eventually the inhibitor became therapy-resistant. However, following the discontinuation of all immunosuppressive therapy, the patient experienced a partial spontaneous remission, which was followed by a pregnancy. During the pregnancy, the FV activity increased to 54% and the coagulation parameters returned to normal levels. The patient underwent Caesarean section without any bleeding complications and delivered a healthy child. Discussion: The use of an activated bypassing agent for bleeding control is effective in patients with severe AFVI. The presented case is unique because the treatment regimens included multiple combinations of immunosuppressive agents. This demonstrates that AFVI patients may undergo spontaneous remission even after multiple courses of ineffective immunosuppressive protocols. Additionally, pregnancy-associated improvement of AFVI is an important finding that warrants further investigation.

Topical Hemostatic Agents in Burn Surgery: A Systematic Review

Acute burn surgery has long been associated with significant intra-operative bleeding. Several techniques were introduced to limit hemorrhage, including tourniquets, tumescent infiltration, and topical agents. To date, no study has comprehensively investigated the available data regarding topical hemostatic agents in burn surgery. A systematic review was performed by two independent reviewers using electronic databases (PubMed, Scopus, Web of Science) from first available to September 10, 2021. Articles were included if they were published in English and described or evaluated topical hemostatic agents used in burn excision and/or grafting. Data were extracted on the agent(s) used, their dosage, mode of delivery, hemostasis outcomes, and complications. The search identified 1982 nonduplicate citations, of which 134 underwent full-text review, and 49 met inclusion criteria. In total, 32 studies incorporated a vasoconstrictor agent, and 28 studies incorporated a procoagulant agent. Four studies incorporated other agents (hydrogen peroxide, tranexamic acid, collagen sheets, and TT-173). The most common vasoconstrictor used was epinephrine, with doses ranging from 1:1000 to 1:1,000,000. The most common procoagulant used was thrombin, with doses ranging from 10 to 1000 IU/ml. Among the comparative studies, outcomes of blood loss were not reported in a consistent manner, therefore meta-analysis could not be performed. The majority of studies (94%) were level of evidence III-V. Determining the optimal topical hemostatic agent is limited by low-quality data and challenges with consistent reporting of intra-operative blood loss. Given the routine use of topical hemostatic agents in burn surgery, high-quality research is essential to determine the optimal agent, dosage, and mode of delivery.

Hemostasis in burn surgery--a review

Over the past 30 years, techniques of early excision and grafting along with enhancement of critical care have significantly improved survival following burn injury. Despite these advancements, large volume blood loss associated with surgical intervention continues to be a challenging aspect of burn surgery. This review article will examine the methods of limiting blood loss during surgical procedures.