Periprocedural Intravascular Hemolysis During Atrial Fibrillation Ablation: A Comparison of Pulsed Field With Radiofrequency Ablation.

BACKGROUND: Hemolysis-related renal failure has been described after pulmonary vein isolation (PVI) with pulsed-field ablation (PFA). OBJECTIVES: This study sought to compare the potential for hemolysis during PVI with PFA vs radiofrequency ablation (RFA). METHODS: In consecutive patients, PVI was performed with PFA or RFA. Blood samples were drawn at baseline, immediately postablation, and 24 hours postablation. Using flow cytometry, the concentration of red blood cell microparticles (RBCµ) (fragments of damaged erythrocytes) in blood was assessed. Lactate dehydrogenase (LDH), haptoglobin, and indirect bilirubin were measured at baseline and 24 hours. RESULTS: Seventy patients (age: 64.7 ± 10.2 years; 47% women; 36 [51.4%] paroxysmal atrial fibrillation) were enrolled: 47 patients were in the PFA group (22 PVI-only and 36.4 ± 5.5 PFA applications; 25 PVI-plus, 67.3 ± 12.4 pulsed field energy applications), and 23 patients underwent RFA. Compared to baseline, the RBCµ concentration increased ∼12-fold postablation and returned to baseline by 24 hours in the PFA group (median: 70.8 [Q1-Q3: 51.8-102.5] vs 846.6 [Q1-Q3: 639.2-1,215.5] vs 59.3 [Q1-Q3: 42.9-86.5] RBCµ/µL, respectively; P < 0.001); this increase was greater with PVI-plus compared to PVI-only (P = 0.007). There was also a significant, albeit substantially smaller, periprocedural increase in RBCµ with RFA (77.7 [Q1-Q3: 39.2-92.0] vs 149.6 [Q1-Q3: 106.6-180.8] vs 89.0 [Q1-Q3: 61.2-123.4] RBCµ/µL, respectively; P < 0.001). At 24 hours with PFA, the concentration of LDH and indirect bilirubin increased, whereas haptoglobin decreased significantly (all P < 0.001). In contrast, with RFA, there were only smaller changes in LDH and haptoglobin concentrations (P = 0.03) and no change in bilirubin. CONCLUSIONS: PFA was associated with significant periprocedural hemolysis. With a number of 70 PFA lesions, the likelihood of significant renal injury is uncommon.

Systematic analysis of mucosal-associated invariant T cells in haematological malignancies.

Mucosal-associated invariant T-cells (MAIT) are unconventional T-cells with cytotoxic and pro-inflammatory properties. Previous research has reported contradictory findings on their role in cancerogenesis with data being even scarcer in haematological malignancies. Here, we report the results of a systematic analysis of MAIT cells in treatment-naïve patients with a broad range of haematological malignancies. We analysed peripheral blood of 204 patients and 50 healthy subjects. The pool of haematological patients had a statistically significant lower both the absolute value (median values, 0.01 × 109/L vs. 0.05 × 109/L) of MAIT cells and their percentage (median values 0.94% vs. 2.56%) among T-cells compared to the control group. Separate analysis showed that the decrease in the absolute number of MAIT cells is significant in patients with acute myeloid leukaemia, myeloproliferative neoplasms, plasma cell myeloma, B-cell non-Hodgkin lymphomas, otherwise not specified, diffuse large B-cell lymphoma, follicular lymphoma, mantle cell lymphoma, marginal zone lymphoma compared to the control population. Furthermore, in haematological malignancies, MAIT cells overexpress PD-1 (average values, 51.7% vs. 6.7%), HLA-DR (average values, 40.2% vs. 7%), CD38 (average values, 25.9% vs. 4.9%) and CD69 (average values, 40.2% vs. 9.2%). Similar results were obtained when comparing patients with individual malignancies to the control population. Our data show that the depletion of circulating MAIT cells is a common observation in a broad spectrum of haematological malignancies. In addition to their reduced numbers, MAIT cells acquire an activated/exhausted phenotype.

Myocardial Damage, Inflammation, Coagulation, and Platelet Activity During Catheter Ablation Using Radiofrequency and Pulsed-Field Energy.

BACKGROUND: Pulsed-field ablation (PFA) represents a new, nonthermal ablation energy for the ablation of atrial fibrillation (AF). Ablation energies producing thermal injury are associated with an inflammatory response, platelet activation, and coagulation activation. OBJECTIVES: This study aimed to compare the systemic response in patients undergoing pulmonary vein isolation (PVI) using pulsed-field and radiofrequency (RF) energy. METHODS: Patients with AF indicated for PVI were enrolled and randomly assigned to undergo PVI using RF (CARTO Smart Touch, Biosense Webster) or pulsed-field (Farapulse, Boston-Scientific) energy. Markers of myocardial damage (troponin I), inflammation (interleukin-6), coagulation (D-dimers, fibrin monomers, von Willebrand antigen and factor activity), and platelet activation (P-selectin, activated GpIIb/IIIa antigen) were measured before the procedure (T1), after trans-septal puncture (T2), after completing the ablation in the left atrium (T3), and 1 day after the procedure (T4). RESULTS: A total of 65 patients were enrolled in the pulsed-field ablation (n = 33) and RF ablation (n = 32) groups. Both groups were similar in baseline characteristics (age 60.5 ± 12.7 years vs 64.0 ± 10.7 years; paroxysmal AF: 60.6% vs 62.5% patients). Procedural and left atrial dwelling times were substantially shorter in the PFA group (55:09 ± 11:57 min vs 151:19 ± 41:25 min; P < 0.001; 36:00 ± 8:05 min vs 115:58 ± 36:49 min; P < 0.001). Peak troponin release was substantially higher in the PFA group (10,102 ng/L [IQR: 8,272-14,207 ng/L] vs 1,006 ng/L [IQR: 603-1,433ng/L]). Both procedures were associated with similar extents (>50%) of platelet and coagulation activation. The proinflammatory response 24 h after the procedure was slightly but nonsignificantly higher in the RF group. CONCLUSIONS: Despite 10 times more myocardial damage, pulsed-field ablation was associated with a similar degree of platelet/coagulation activation, and slightly lower inflammatory response. (The Effect of Pulsed-Field and Radiofrequency Ablation on Platelet, Coagulation and Inflammation; NCT05603637).

High pre-transplant Mucosal Associated Invariant T Cell (MAIT) count predicts favorable course of myeloid aplasia.

AIMS: Mucosal Associated Invariant T (MAIT) cells are unconventional T cells with anti-infective potential. MAIT cells detect and fight against microbes on mucosal surfaces and in peripheral tissues. Previous works suggested that MAIT cells survive exposure to cytotoxic drugs in these locations. We sought to determine if they maintain their anti-infective functions after myeloablative chemotherapy. METHODS: We correlated the amount of MAIT cells (measured by flow cytometry) in the peripheral blood of 100 adult patients before the start of myeloablative conditioning plus autologous stem cell transplantation with the clinical and laboratory outcomes of aplasia. RESULTS: The amount of MAIT cells negatively correlated with peak C-reactive protein level and the amount of red blood cell transfusion units resulting in earlier discharge of patients with the highest amount of MAIT cells. CONCLUSION: This work suggests the anti-infectious potential of MAIT cells is maintained during myeloid aplasia.

Cellular and humoral immune response to SARS-CoV-2 mRNA vaccines in patients treated with either Ibrutinib or Rituximab.

Patients treated with B-cell-targeting therapies like Rituximab or Ibrutinib have decreased serological response to various vaccines. In this study, we tested serological and cellular response to SARS-CoV-2 mRNA vaccines in 16 patients treated with Ibrutinib, 16 treated with maintenance Rituximab, 18 patients with chronic lymphocytic leukaemia (CLL) with watch and wait status and 21 healthy volunteers. In comparison with the healthy volunteers, where serological response was achieved by 100% subjects, patients on B-cell-targeting therapy (Ibrutinib and Rituximab) had their response dramatically impaired. The serological response was achieved in 0% of Rituximab treated, 18% of Ibrutinib treated and 50% of untreated CLL patients. Cell-mediated immunity analysed by the whole blood Interferon-γ Release immune Assay developed in 80% of healthy controls, 62% of Rituximab treated, 75% of Ibrutinib treated and 55% of untreated CLL patients. The probability of cell-mediated immune response development negatively correlates with disease burden mainly in CLL patients. Our study shows that even though the serological response to SARS-CoV-2 vaccine is severely impaired in patients treated with B-cell-targeting therapy, the majority of these patients develop sufficient cell-mediated immunity. The vaccination of these patients therefore might be meaningful in terms of protection against SARS-CoV-2 infection.

Acute myeloid leukemia with variant t(8;10;21).

The t(8;21)(q22;q22) is one of the most common chromosomal abnormalities in acute myeloid leukemia (AML). Approximately 3-4% of AML cases are associated with additional chromosomal abnormalities. Their impact on the prognosis of the disease remains to be established. Here we report a case of t(8;10;21) AML with mutated c-KIT that shared key morphological features with classical t(8;21) leukemias, including the M2 morphology pattern and CD34, HLA-DR phenotype. The 63-year-old female was treated with two inductioncontaining Daunoribicine and Cytarabine and four cycles of intermediate-dose Cytarabine (1.5 g/m2) and achieved long-lasting remission.

Sex differences in endothelial function of aged hypertriglyceridemic rats - effect of atorvastatin treatment.

The aim of the study was to test the hypothesis that the effect of atorvastatin on endothelium-dependent relaxation of the superior mesenteric artery (SMA) may differ in male vs. female aged hypertriglyceridemic rats (HTGs). Experiments were performed on 11-month-old male and female Prague hereditary HTGs. Atorvastatin (ATO) was administered p.o. in the dose of 0.30 mg/100g/day. Controls received vehiculum. After two months of ATO administration blood pressure, serum triglycerides (TG) and total cholesterol (CHOL) were determined. Endothelial function of SMA was studied in vitro using evaluation of relaxant responses of precontracted SMA to acetylcholine. The serum TG of control male HTGs were found to be statistically higher than those of female controls, while CHOL and blood pressure did not share gender differences. Responses of SMA of female control HTGs were statistically decreased compared to their male counterparts. ATO treatment induced decrease in blood pressure and TG of both males and females, yet CHOL values were reduced only in females. The protective effect of ATO on SMA endothelial function was much more pronounced in females compared to males. We conclude that vascular endothelial dysfunction of aged HTG rats is more severe and more attenuated by ATO in females compared to males. The protective effect of ATO on vascular endothelial function does not seem to depend solely on its lipid lowering action.

Distinct lethal arrhythmias susceptibility is associated with sex-related difference in myocardial connexin-43 expression.

OBJECTIVES: To elucidate gender-related differences in occurrence of sudden cardiac death the myocardial connexin-43 (Cx43) and the susceptibility of male and female rat hearts to ventricular fibrillation (VF) were investigated. METHODS AND RESULTS: Ventricular tissues taken from male and female normotensive Wistar and spontaneously hypertensive (SHR) rats were processed for immuno-fluorescence and immuno-blotting of Cx43. Susceptibility to ventricular fibrillation was examined in isolated heart preparation using either electrical stimulation or low K+ perfusion. Results showed that VF susceptibility of male either normotensive or hypertensive rats was significantly increased comparing to female counterparts. In correlation, ventricular expression of Cx43 was markedly lower in males of both normotensive and hypertensive rats comparing to females. SHR in addition exhibited abnormal myocardial Cx43 distribution due to structural remodelling. CONCLUSIONS: Findings indicate that higher level of myocardial Cx43 expression is linked with lower lethal arrhythmia susceptibility and vice versa. It appears that Cx43 can be involved in sex-related differences in incidence of life-threatening arrhythmias.