Effects of Serum Potassium on Mortality in Patients With ST-Elevation Myocardial Infarction.

INTRODUCTION: Disturbances in potassium levels can induce ventricular arrhythmias and heighten mortality in patients with ST-elevation myocardial infarction (STEMI). This study evaluates the influence of sK levels on seven-day mortality and incidence of ventricular arrhythmias in STEMI patients to further improve clinical guidelines and outcomes. METHODS: This retrospective, propensity-matched study analyzed approximately 250,000 acute STEMI patients from 55 major academic medical centers/healthcare organizations (HCOs) in the US Collaborative Network of the TriNetX database. The sK levels recorded on the day of STEMI diagnosis were categorized into four cohorts: sK ≤ 3.4 (hypokalemia), 3.5 ≤ sK ≤ 4.5 (normal-control), 4.6 ≤ sK ≤ 5.0 (high-normal), and sK ≥ 5.1 (hyperkalemia). Patient cohorts were propensity-matched using linear and logistic regression for demographics. Outcomes of seven-day mortality, ventricular tachycardia (VT), and ventricular fibrillation (VF) were compared between these cohorts and the control group. RESULTS: The analysis showed hypokalemia was linked to significantly higher seven-day mortality (7.2% vs. 4.3%; RR 1.69; p<0.001), and increased rates of VT and VF. Similarly, hyperkalemia was associated with elevated mortality (12.7% vs. 4.6%; RR 2.76; p<0.001), VT, and VF rates. High-normal sK levels showed increased mortality (7.4% vs. 4.7%; RR 1.58; p<0.001), but unchanged VT or VF rates compared to the normal sK group. CONCLUSION: This comprehensive study highlights the correlation of sK levels with death in STEMI patients, revealing a nearly doubled risk of mortality with hypokalemia and almost triples with hyperkalemia. More notably, the mortality for STEMIs is higher for high-normal vs normal sK values. Additionally, hypokalemia and hyperkalemia were found to significantly elevate VT and VF risks.

Support for Thrombolytic Therapy for Acute Stroke Patients on Direct Oral Anticoagulants: Mortality and Bleeding Complications.

Background: Alteplase (tPA) is the initial treatment for acute ischemic stroke. Current tPA guidelines exclude patients who took direct oral anticoagulants (DOAC) within the prior 48 hours. In this propensity-matched retrospective study we compared acute ischemic stroke patients treated with tPA who had received DOACs within 48 hours of thrombolysis to those not previously treated with DOACs, regarding three outcomes: mortality; intracranial hemorrhage (ICH); and need for acute blood transfusions (as a marker of significant blood loss). Methods: Using the United States cohort of 54 healthcare organizations in the TriNetx database, we identified 8,582 stroke patients treated with tPA on DOACs within 48 hours of thrombolysis and 46,703 stroke patients treated with tPA not on DOACs since January 1, 2012. We performed propensity score matching on demographic information and seven prior clinical diagnostic groups, resulting in a total of 17,164 acute stroke patients evenly matched between groups. We recorded mortality rates, frequency of ICH, and need for blood transfusions for each group over the ensuing 7- and 30-day periods. Results: Patients treated with tPA on DOACs had reduced mortality (3.3% vs 7.3%; risk ratio [RR] 0.456; P < 0.001), fewer ICHs (6.8% vs 10.1%; RR 0.678; P < 0.001), and less risk of major bleeding as measured by frequency of blood transfusions (0.5% vs 1.5%; RR 0.317; p < 0.001) at 7 days post thrombolytic, than the tPA patients not on DOACS. Findings for 30 days post-thrombolytics were similar/statistically significant with lower mortality rate (7.2% vs 13.1%; RR 0.550; P < 0.001), fewer ICHs (7.6% vs 10.8%; RR 0.705; P < 0.001), and fewer blood transfusions (0.9% vs 2.0%; RR 0.448; P < 0.001). Conclusion: Acute ischemic stroke patients treated with tPA who received DOACs within 48 hours of thrombolysis had lower mortality rates, reduced incidence of ICH, and less blood loss than those not on DOACs. Our study suggests that prior use of DOACs should not be a contraindication to thrombolysis for ischemic stroke.

Tenecteplase Versus Alteplase for Acute Stroke: Mortality and Bleeding Complications.

STUDY OBJECTIVE: Intravenous thrombolysis with alteplase has been the foundation of initial treatment of acute ischemic stroke for several decades. Tenecteplase is a thrombolytic agent that offers logistical advantages in cost and administration relative to alteplase. There is evidence that tenecteplase has at least similar efficacy and safety outcomes compared with alteplase for stroke. In this study, we compared tenecteplase versus alteplase for acute stroke in a large retrospective US database (TriNetX) regarding the following 3 outcomes: (1) mortality, (2) intracranial hemorrhage, and (3) the need for acute blood transfusions. METHODS: In this retrospective study using the US cohort of 54 academic medical centers/health care organizations in the TriNetX database, we identified 3,432 patients treated with tenecteplase and 55,894 patients treated with alteplase for stroke after January 1, 2012. Propensity score matching was performed on basic demographic information and 7 previous clinical diagnostic groups, resulting in a total of 6,864 patients with acute stroke evenly matched between groups. Mortality rates, the frequency of intracranial hemorrhage, and blood transfusions (as a marker of significant blood loss) were recorded for each group over the ensuing 7- and 30-day periods. Secondary subgroup analyses were conducted on a cohort treated from 2021 to 2022 in an attempt to determine whether temporal differences in acute ischemic stroke treatment would alter the results. RESULTS: Patients treated with tenecteplase had a significantly lower mortality rate (8.2% versus 9.8%; risk ratio [RR], 0.832) and lower risk of major bleeding as measured by the frequency of blood transfusions (0.3% versus 1.4%; RR, 0.207) than alteplase at 30 days after thrombolysis for stroke. In the larger 10-year data set of patients with stroke treated after January 1, 2012, patients receiving tenecteplase were not found to have a statistically different incidence of intracranial hemorrhage (3.5% versus 3.0%; RR, 1.185) at 30 days after the administration of the thrombolytic agents in patients. However, a subgroup analysis of 2,216 evenly matched patients with stroke treated from 2021 to 2022 demonstrated notably better survival and statistically lower rates of intracranial hemorrhage than the alteplase group. CONCLUSION: In our large retrospective multicenter study using real-world evidence from large health care organizations, tenecteplase for the treatment of acute stroke demonstrated a lower mortality rate, decreased intracranial hemorrhage, and less significant blood loss. The favorable mortality and safety profiles observed in this large study, taken together with previous randomized controlled trial data and operational advantages in rapid dosing and cost-effectiveness, all support the preferential use of tenecteplase in patients with ischemic stroke.

Folding is coupled to dimerization of Tctex-1 dynein light chain.

Equilibrium analyses have been performed to elucidate the role of dimerization in folding and stability of dynein light chain Tctex-1. The equilibrium unfolding transition was monitored by intrinsic fluorescence intensity, fluorescence anisotropy, and circular dichroism and was modeled as a two-state mechanism where a folded dimer dissociates to two unfolded monomers without populating thermodynamically stable monomeric or dimeric intermediates. Sedimentation equilibrium and chemical cross-linking experiments performed at increasing concentrations of denaturants show no change in the association state before the unfolding transition and are consistent with the two-state model of dissociation coupled to unfolding. A linear dependence on denaturant concentration is observed by fluorescence intensity and anisotropy before unfolding in the 0-2 M GdnCl, and 0-4 M urea concentration range. This change is not protein concentration-dependent and possibly reflects relief of quenching associated with premelting conformational disorder in the vicinity of Trp 83. The data clearly show that the dissociation-coupled unfolding mechanism of Tctex-1 is different from the three-state denaturation mechanism of its structural homologue light chain LC8. The absence of a stable monomer in Tctex-1 offers insight into its functional differences from LC8.