Hemostasis system in patients with bradycardias after the implantation of dual-chamber pacemakers

Introduction: As with many other surgical interventions, the implantation of a pacemaker may be associated with adverse outcomes in the immediate or distant period. The search for probable risk factors of adverse outcomes may promote the development of effective and safe management methods of patients with pacemaker postoperatively. One of the important directions in this field is the investigation of the effect of pacemaker implantation on the hemostasis system of these patients.

Aim: To evaluate the effect of the implantation of dual-chamber pacemaker on the hemostasis system of patients with different kinds of bradyarrhythmias and to determine probable risk factors for unfavorable outcomes in this groupof patients.

Materials and methods: The study was performed with the financial support of the Russian Foundation for Basic Research within the Scientific Project No. 19-315-90109. The prospective study (ClinicalTrials.gov ID, NCT04499612) enrolled 61 patients (men, 45.9%) with a mean age of 71.5 ± 8.8 years. The groupwho received surgical treatment included 23 patients with atrioventricular (AV) block and 25 patients with sick sinus syndrome (SSS), and the groupwith conservative treatment included 13 patients with AV blocks and SSS, but without indications for pacemaker implantation. Anticoagulant therapy was given to one patient with AV block, 12 patients with SSS, and five patients with conservative therapy. All the remaining patients received antiplatelet therapy. The surgical groupunderwent ultrasound examination of the veins of the upper and lower extremities and sampling of peripheral venous blood before and 7 days after pacemaker implantation to determine the level of fibrinogen (FI) and activity of blood coagulation factors VIII (FVIII) and IX (FIX), antithrombin III (AT III), and protein C. In the conservative group, a similar examination was conducted only on inclusion in the study.

Results:  In patients with AV block, a significant increase in blood fibrinogen was noted at 7 days after surgery (р=0.042). In the intergroupcomparison, the activity of AT III after the implantation was higher in the surgical groupthan in the conservative group(р=0.018 and р=0.006, respectively). After surgery, the activity of FVIII and FIX was lower in patients with SSS on anticoagulant therapy than in patients with antiplatelet therapy (р=0.048 and р=0.015, respectively). Based on the receiver operating characteristics analysis, the risk factors for lethal outcomes were reduced activity of AT III in patients with AV block and increased activity of FIX in patients with SSS.

Conclusions: The balance of the hemostasis system in patients with AV blocks on antiplatelet therapy was shifted toward hypercoagulation within at least 7 days after pacemaker implantation. The use of anticoagulants in patients with SSS caused a shift toward hypocoagulation. The reduced activity of AT III in patients with AV block and increased activity of FIX in patients with SSS are prognostic factors for lethal outcomes.