The Phenomenon of Thrombotic Microangiopathy in Cancer Patients.

Thrombotic microangiopathy (TMA) encompasses a range of disorders characterized by blood clotting in small blood vessels, leading to organ damage. It can manifest as various syndromes, including thrombotic thrombocytopenic purpura (TTP), hemolytic-uremic syndrome (HUS), and others, each with distinct causes and pathophysiology. Thrombo-inflammation plays a significant role in TMA pathogenesis: inflammatory mediators induce endothelial injury and activation of platelet and coagulation cascade, contributing to microvascular thrombosis. Primary TMA, such as TTP, is primarily caused by deficient ADAMTS13 metalloproteinase activity, either due to antibody-mediated inhibition or intrinsic enzyme synthesis defects. In cancer patients, a significant reduction in ADAMTS13 levels and a corresponding increase in VWF levels is observed. Chemotherapy further decreased ADAMTS13 levels and increased VWF levels, leading to an elevated VWF/ADAMTS13 ratio and increased thrombotic risk. Drug-induced TMA (DITMA) can result from immune-mediated or non-immune-mediated mechanisms. Severe cases of COVID-19 may lead to a convergence of syndromes, including disseminated intravascular coagulation (DIC), systemic inflammatory response syndrome (SIRS), and TMA. Treatment of TMA involves identifying the underlying cause, implementing therapies to inhibit complement activation, and providing supportive care to manage complications. Plasmapheresis may be beneficial in conditions like TTP. Prompt diagnosis and treatment are crucial to prevent serious complications and improve outcomes.

Predictors of Premature Ventricular Contractions Development in Patients With SARS-CoV-2 Infection.

Background: Epidemiological studies have demonstrated that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)-positive patients often develop atrial fibrillation, premature ventricular contractions (PVCs), and conduction disorders. The manifestation of ventricular cardiac arrhythmias accentuates the risk of sudden cardiac death. Methods: A retrospective study was conducted on the cohort of 1,614 patients admitted for coronavirus disease 2019 (COVID-19). Patients were categorized into two groups based on the occurrence of PVCs. Group I comprised 172 patients diagnosed with PVCs of Lown-Wolf class II - IV upon hospital admission; group II (control group) consisted of 1,442 patients without this arrhythmia. Each patient underwent comprehensive clinical, laboratory, and instrumental evaluations. Results: The emergence of PVCs in individuals afflicted with COVID-19 was associated with a 5.879-fold heightened risk of lethal outcome, a 2.904-fold elevated risk of acute myocardial infarction, and a 2.437-fold increased risk of pulmonary embolism. Upon application of diagnostic criteria to evaluate the "cytokine storm", it was discovered that the occurrence of the "cytokine storm" was notably more frequent in the group with PVCs, manifesting in six patients (3.5%), compared to 16 patients (1.1%) in the control group (P < 0.05). The mean extent of lung tissue damage in group I was significantly greater than that of patients in group II (P < 0.05). Notably, the average oxygen saturation level, as measured by pulse oximetry upon hospital admission was 92.63±3.84% in group I and 94.20±3.50% in group II (P < 0.05). Conclusions: The presence of PVCs in COVID-19 patients was found to elevate the risk of cardiovascular complications. Significant independent predictors for the development of PVCs in patients with SARS-CoV-2 infection include: age over 60 years (risk ratio (RR): 4.6; confidence interval (CI): 3.2 - 6.5), a history of myocardial infarction (RR: 3.5; CI: 2.6 - 4.6), congestive heart failure (CHF) with reduced left ventricular ejection fraction (RR: 5.5; CI: 3.9 - 7.6), respiratory failure (RR: 2.3; CI: 1.7 - 3.1), and the presence of a "cytokine storm" (RR: 4.5; CI: 2.9 - 6.0).