Antifibrinolytics and cardiac surgery: The past, the present, and the future

Lack of efficacy of aprotinin over tranexamic acid in type A aortic dissection repair

BACKGROUND

The role of aprotinin in modern cardiac surgery is not well defined. While licensed for use in isolated coronary artery bypass grafting it is more commonly used for cases deemed to be at an increased risk of bleeding. The relative efficacy, and safety profile, of aprotinin as compared to other antifibrinolytics in these high-risk cases is uncertain.

STUDY DESIGN AND METHODS

A retrospective observational study with propensity matching to determine whether aprotinin versus tranexamic acid reduced bleeding or transfusion requirements in patients presenting for surgical repair of type A aortic dissection (TAD).

RESULTS

Between 2016 and 2022, 250 patients presented for repair of TAD. A total of 231 patients were included in the final analysis. Bleeding and transfusion were similar between both groups in both propensity matched and unmatched cohorts. Compared to tranexamic acid, aprotinin use did not reduce transfusion requirements for any product. Rates of bleeding in the first 12 h, return to theater and return to intensive care unit with an open packed chest were similar between groups. There was no difference in rates of renal failure, stroke, or death.

CONCLUSION

Aprotinin did not reduce the risk of bleeding or transfusion requirements in patients undergoing repair of type A aortic dissections. Efficacy of aprotinin may vary depending on the type of surgery performed and the underlying pathology.

A Novel Trypsin Kunitz-Type Inhibitor from Cajanus cajan Leaves and Its Inhibitory Activity on New Cancer Serine Proteases and Its Effect on Tumor Cell Growth

A novel trypsin inhibitor from Cajanus cajan (TIC) fresh leaves was partially purified by affinity chromatography. SDS-PAGE revealed one band with about 15 kDa with expressive trypsin inhibitor activity by zymography. TIC showed high affinity for trypsin (Ki = 1.617 μM) and was a competitive inhibitor for this serine protease. TIC activity was maintained after 24 h of treatment at 70 °C, after 1 h treatments with different pH values, and β-mercaptoethanol increasing concentrations, and demonstrated expressive structural stability. However, the activity of TIC was affected in the presence of oxidizing agents. In order to study the effect of TIC on secreted serine proteases, as well as on the cell culture growth curve, SK-MEL-28 metastatic human melanoma cell line and CaCo-2 colon adenocarcinoma was grown in supplemented DMEM, and the extracellular fractions were submitted salting out and affinity chromatography to obtain new secreted serine proteases. TIC inhibited almost completely, 96 to 89%, the activity of these serine proteases and reduced the melanoma and colon adenocarcinoma cells growth of 48 and 77% respectively. Besides, it is the first time that a trypsin inhibitor was isolated and characterized from C. cajan leaves and cancer serine proteases were isolated and partial characterized from SK-MEL-28 and CaCo-2 cancer cell lines. Furthermore, TIC shown to be potent inhibitor of tumor protease affecting cell growth, and can be one potential drug candidate to be employed in chemotherapy of melanoma and colon adenocarcinoma.

Anesthetic Management of Middle Aortic Syndrome in an Adult: A Case Report

Middle aortic syndrome (MAS) is a rare disorder characterized by narrowing of the aorta. Depending on the location and extent of aortic narrowing, surgical management may be necessary to prevent long-term sequelae, such as stroke and congestive heart failure. We report a case of MAS and discuss the unique intraoperative anesthetic considerations including hemodynamic monitoring proximal and distal to the aortic narrowing, minimizing the risk of spinal cord ischemia, and utilization of intraoperative dobutamine stress testing to guide surgical management.

Antifibrinolytics in the treatment of traumatic brain injury

PURPOSE OF REVIEW

Traumatic brain injury (TBI) is a leading cause of trauma-related deaths, and pharmacologic interventions to limit intracranial bleeding should improve outcomes. Tranexamic acid reduces mortality in injured patients with major systemic bleeding, but the effects of antifibrinolytic drugs on outcomes after TBI are less clear. We therefore summarize recent evidence to guide clinicians on when (not) to use antifibrinolytic drugs in TBI patients.

RECENT FINDINGS

Tranexamic acid is the only antifibrinolytic drug that has been studied in patients with TBI. Several recent studies failed to conclusively demonstrate a benefit on survival or neurologic outcome. A large trial with more than 12 000 patients found no significant effect of tranexamic acid on head-injury related death, all-cause mortality or disability across the overall study population, but observed benefit in patients with mild to moderate TBI. Observational evidence signals potential harm in patients with isolated severe TBI.

SUMMARY

Given that the effect of tranexamic acid likely depends on a variety of factors, it is unlikely that a 'one size fits all' approach of administering antifibrinolytics to all patients will be helpful. Tranexamic acid should be strongly considered in patients with mild to moderate TBI and should be avoided in isolated severe TBI.

Osmotic Adaptation by Na+-Dependent Transporters and ACE2: Correlation with Hemostatic Crisis in COVID-19

COVID-19 symptoms, including hypokalemia, hypoalbuminemia, ageusia, neurological dysfunctions, D-dimer production, and multi-organ microthrombosis reach beyond effects attributed to impaired angiotensin-converting enzyme 2 (ACE2) signaling and elevated concentrations of angiotensin II (Ang II). Although both SARS-CoV (Severe Acute Respiratory Syndrome Coronavirus) and SARS-CoV-2 utilize ACE2 for host entry, distinct COVID-19 pathogenesis coincides with the acquisition of a new sequence, which is homologous to the furin cleavage site of the human epithelial Na+ channel (ENaC). This review provides a comprehensive summary of the role of ACE2 in the assembly of Na+-dependent transporters of glucose, imino and neutral amino acids, as well as the functions of ENaC. Data support an osmotic adaptation mechanism in which osmotic and hemostatic instability induced by Ang II-activated ENaC is counterbalanced by an influx of organic osmolytes and Na+ through the ACE2 complex. We propose a paradigm for the two-site attack of SARS-CoV-2 leading to ENaC hyperactivation and inactivation of the ACE2 complex, which collapses cell osmolality and leads to rupture and/or necrotic death of swollen pulmonary, endothelial, and cardiac cells, thrombosis in infected and non-infected tissues, and aberrant sensory and neurological perception in COVID-19 patients. This dual mechanism employed by SARS-CoV-2 calls for combinatorial treatment strategies to address and prevent severe complications of COVID-19.