Initial Activated Clotting Time Research Articles

Protamine Dosing for Heparin Reversal after Cardiopulmonary Bypass: A Double-blinded Prospective Randomized Control Trial Comparing Two Strategies.

Drug shortages are a frequent challenge in current clinical practice. Certain drugs (e.g., protamine) lack alternatives, and inadequate supplies can limit access to services. Conventional protamine dosing uses heparin ratio-based calculations for heparin reversal after cardiopulmonary bypass and may result in excess protamine utilization and potential harm due to its intrinsic anticoagulation. This study hypothesized that a fixed 250-mg protamine dose would be comparable, as measured by the activated clotting time, to a 1:1 (1 mg for every 100 U) protamine-to-heparin ratio-based strategy for heparin reversal and that protamine would be conserved. In a single-center, double-blinded trial, consenting elective adult cardiac surgical patients without preexisting coagulopathy or ongoing anticoagulation and a calculated initial heparin dose greater than or equal to 27,500 U were randomized to receive, after cardiopulmonary bypass, protamine as a fixed dose (250 mg) or a ratio-based dose (1 mg:100 U heparin). The primary outcome was the activated clotting time after initial protamine administration, assessed by Student's t test. Secondary outcomes included total protamine, the need for additional protamine, and the cumulative 24-h chest tube output. There were 62 and 63 patients in the fixed- and ratio-based dose groups, respectively. The mean postprotamine activated clotting time was not different between groups (-2.0 s; 95% CI, -7.2 to 3.3 s; P = 0.47). Less total protamine per case was administered in the fixed-dose group (-2.1 50-mg vials; 95% CI, -2.4 to -1.8; P < 0.0001). There was no difference in the cumulative 24-h chest tube output (difference, -77 ml; 95% CI, 220 to 65 ml; P = 0.28). A 1:1 heparin ratio-based protamine dosing strategy compared to a fixed 250-mg dose resulted in the administration of a larger total dose of protamine but no difference in either the initial activated clotting time or the amount postoperative chest-tube bleeding.

Factors associated with silent cerebral events during catheter ablation for atrial fibrillation in the era of uninterrupted oral anticoagulation therapy

Abstract Background A silent cerebral event (SCE), detected by brain magnetic resonance imaging (MRI), is defined as an acute new brain lesion without clinically apparent neurological deficit, and is frequently observed after catheter ablation in atrial fibrillation (AF) patients. Although the small number of SCEs does not cause neurocognitive dysfunction, the greater volume and/or larger number of SCE lesions are reportedly related to neuropsychological decline; SCE incidence may be a surrogate marker for the potential thromboembolic risk. Thus, strategies to reduce SCEs would be beneficial. Uninterrupted oral anticoagulation strategy for peri-procedural period reportedly reduced the risk of SCEs, but the incidence hovers at 10% to 30%. We sought factors associated with SCEs during catheter ablation for AF in patients with peri-procedural uninterrupted oral anticoagulation (OAC) therapy. Methods AF patients undergoing catheter ablation were eligible (n=255). All patients took non-vitamin K antagonist oral anticoagulants (NOACs) or vitamin K antagonist (VKA) for peri-procedural OAC (&amp;gt;4 weeks) without interruption during the procedure. Brain MRI was performed within 2 days after the procedure to detect SCEs. Clinical characteristics and procedure-related parameters were compared between patients with and without SCEs. Results SCEs were detected in 59 patients (23%, SCE[+]) but not in 196 patients (77%, SCE[-]). Average age was higher in SCE[+] than SCE[-] (66±10 years vs. 62±12 years, p&amp;lt;0.05). Persistent AF prevalence, CHADS2/CHA2DS2-VASc scores, and serum NT-ProBNP levels increased in SCE[+] vs. SCE[-]. In transthoracic/transesophageal echocardiography, left-atrial dimension (LAD) was larger and AF rhythm/spontaneous echo contrast were more frequently observed in SCE[+] than SCE[-]. SCE[+] had lower initial activated clotting time (ACT) before unfractionated heparin (UFH) injection and longer time to reach optimal ACT (&amp;gt;300 sec) before trans-septal puncture than SCE [-]. In multivariate analysis, LAD, initial ACT before UFH injection, and time to reach optimal ACT were predictors for SCEs. Conclusions LAD and intra-procedural ACT kinetics affect SCEs during the procedure in patients with uninterrupted OAC for AF ablation. Shortening time to achieve optimal ACT during the procedure may reduce the risk of SCEs. Funding Acknowledgement Type of funding source: None

Risk factors for the development of significant postoperative bleeding after pediatric cardiac surgery with cardiopulmonary bypass: A nested case-control study

Background: Postoperative bleeding of more than 10% of circulating blood volume (CBV) within the first six hours after a cardiac surgery with cardiopulmonary bypass (CBS) is one of the most frequent complications associated with postoperative morbidity and mortality in children. Objectives: This study aimedto identify specific risk factors for the development of this complication in a subpopulation of Mexican pediatric patients. Methods: A nested case-control study was conducted at a tertiary level pediatric intensive care unit (PICU) of Mexico City. Cases were those children who developed bleeding of more than 10% of circulating blood volume (CBV) within the first six hours after the surgery and controls were all those children who did not presented this complication. Bivariate and logistic regression analyses were performed. A P-value less than 0.05 was considered as statistically significant. Results: Results showed that 33% (n = 21) of included children developed significant bleeding in the first six hours after the cardiac surgery. The main risk factors for developing this complication were the cyanotic congenital heart disease (P 60 minutes (P = 0.01), intraoperative bleeding volume (P = 0.04), and an initial activated clotting time > 140 seconds (P < 0.01). Conclusions: An important proportion of patients developed postoperative significant bleeding. Risk factors identified in the present study could help to identify and close monitor a subgroup of children at high risk for the development of this complication.