Evaluation of Latex Immunoturbidimetric Assay Thresholds and HIT in Cardiothoracic Surgery.

BACKGROUND: Heparin-induced thrombocytopenia (HIT) is a common differential diagnosis in cardiothoracic surgery. The latex immunoturbidimetric assay (LIA) is an enhanced immunoassay that has recently been introduced for the detection of total HIT immunoglobulin and retains a higher specificity of 95% compared to the enzyme-linked immunosorbent assay. OBJECTIVES: To investigate if a semiquantitative relationship exists between increasing LIA levels beyond the current positivity threshold and its correlation to positive serotonin release assay results in cardiothoracic surgery. METHODS: This was a multicenter, observational cohort of cardiothoracic surgery patients initiated on anticoagulation with heparin-based products. To conduct sensitivity and specificity analysis of LIA values, HIT positive was defined as a LIA value ≥1 unit/mL and HIT negative was defined as a LIA level <1 unit/mL. A receiver operating characteristic (ROC) analysis was utilized to evaluate the predictive performance of the LIA. RESULTS: At manufactures' cutoffs of ≥1.0 unit/mL, LIA sensitivity and specificity was 93.8% and 22%, respectively, yielding a false positive rate of 78%. At a higher cutoff of 4.5 units/mL, LIA sensitivity and specificity was 75% and 71%, respectively, yielding a false positive rate of 29% and an area under the ROC curve of 0.75 (P = .01; 95% confidence interval: 0.621-0.889). Bivalirudin was initiated in 84.6% of false positive LIA results. CONCLUSION: This study suggests that the diagnostic accuracy of the LIA can be optimized by increasing the LIA positivity threshold. Proposing a higher LIA cutoff, may mitigate unwarranted anticoagulation and bleeding outcomes.

Benzonatate Safety and Effectiveness: A Systematic Review of the Literature.

OBJECTIVE: To review the available literature regarding the treatment effects and efficacy of benzonatate needed to better inform patients, providers, and regulators evaluating its role in modern medical therapies. DATA SOURCES: Comprehensive literature searches were conducted in PubMed, Embase (Elsevier), Cochrane Library, and Scopus for original research articles evaluating the effectiveness, tolerability, and safety profile of benzonatate from January 1956 through August 2022. STUDY SELECTION AND DATA EXTRACTION: The identified studies were screened for relevance and then assessed for inclusion through a full-text review, data extraction, and quality assessment by multiple reviewers using the online software Covidence. DATA SYNTHESIS: The selection process resulted in 37 articles consisting of 21 cohort studies, 5 experimental studies, and 11 case studies and series. Initial clinical studies exploring potential therapeutic benefits collected data from very small populations and limited clinical settings. Safety is primarily assessed in terms of toxicity due to overdose or inappropriate use. Quality assessment raised concerns for high degrees of biases primarily related to the limited sample size, data collection, generalizability, and study design. RELEVANCE TO PATIENT CARE AND CLINICAL PRACTICE: This review reveals substantial limitations within existing evidence pertaining to the safety and clinical effectiveness of benzonatate and thus, a need for large observational studies or randomized trials to better characterize its role and value in modern medical practice. CONCLUSIONS: Rising safety concerns should bring closer scrutiny upon the prescription of benzonatate whose approval is founded upon evidence that would not stand up to current regulatory review.

Analysis of Bicarbonate-Based Purge Solution in Patients With Cardiogenic Shock Supported Via Impella Ventricular Assist Device.

BACKGROUND: The Impella device is a continuous axial flow pump which provides hemodynamic support by expelling blood into the aorta. The manufacturer recommends using dextrose-based heparin containing solutions as the default purge. As an alternative to anticoagulant solutions, a bicarbonate-based purge solution has been proposed with limited data substantiating adequate protection and durability. OBJECTIVE: To assess the impact of a bicarbonate-based purge solution on Impella pump thrombosis and bleeding outcomes. METHODS: Single-center, retrospective study of cardiogenic shock patients who received an Impella between December 2020 through September 2021. Patients were evaluated based on whether they received bicarbonate-based purge solutions or remained on heparin-based purge solutions. The primary outcome was the rate of Impella pump thrombosis, defined as multiple purge pressures greater than 800 mm Hg. Secondary outcomes included incidence of bleeding defined as a drop in Hgb of at least 2 g/dL along with use of blood products and supratherapeutic anticoagulation defined as an aPTT of greater than 70 seconds. RESULTS: Forty-three patients received bicarbonate-based purge solutions and 49 controls received heparin. The incidence of purge thrombosis by purge pressure threshold was similar between the two groups (16.3% vs 12.2%, P = 0.58). The rate of bleeding was lower with bicarbonate-based purge (27.9% vs 65.3%, P < 0.05) driven by a drop in Hgb of more than 2 g/dL. The rate of supratherapeutic anticoagulation was higher in the heparin arm (65.3% vs 27.9%, P < 0.05). CONCLUSION AND RELEVANCE: Nonanticoagulant purge alternatives offer the potential to reduce bleeding complications and laboratory monitoring burden while maintaining durability.

Renin Angiotensin Aldosterone System Antagonism in 2019 Novel Coronavirus Acute Lung Injury.

It has been established that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses angiotensin-converting enzyme 2 (ACE2), a membrane-bound regulatory peptide, for host cell entry. Renin-angiotensin-aldosterone system (RAAS) inhibitors have been reported to increase ACE2 in type 2 pneumocyte pulmonary tissue. Controversy exists for the continuation of ACE inhibitors, angiotensin II receptor blockers, and mineralocorticoid receptor antagonists in the current pandemic. ACE2 serves as a regulatory enzyme in maintaining homeostasis between proinflammatory angiotensin II and anti-inflammatory angiotensin 1,7 peptides. Derangements in these peptides are associated with cardiovascular disease and are implicated in the progression of acute respiratory distress syndrome. Augmentation of the ACE2/Ang 1,7 axis represents a critical target in the supportive management of coronavirus disease 2019-associated lung disease. Observational data describing the use of RAAS inhibitors in the setting of SARS-CoV-2 have not borne signals of harm to date. However, equipoise persists, requiring an analysis of novel agents including recombinant human-ACE2 and existing RAAS inhibitors while balancing ongoing controversies associated with increased coronavirus infectivity and virulence.