Local Use of Hydrogel with Amiodarone in Cardiac Surgery: Experiment and Translation to the Clinic

The objective of this study was to study the use of the hydrogel biopolymer based on sodium alginate ("Colegel") with a drug substance-amiodarone-for the prevention of postoperative atrial fibrillation (POAF) in cardiac surgery. The experimental part of the study was performed on 46 rabbits. Five groups were formed: in the first group, the dose of amiodarone in hydrogel was 1 mg; in the second group-3 mg; in the third group-6 mg; in the fourth group, hydrogel was used without amiodarone; in the fifth group, 60 mg amiodarone was administered intravenously. The animals from each group were removed from the experiment for the pathomorphological study of the heart after 3, 7 and 14 days. The studied endpoints were: the heart rate control; the development of the blockades of the conduction system of the heart; and the development of inflammation according to laboratory pathomorphological studies. The translational clinical part involved a randomized clinical trial which included 60 patients, with an average age of 62 ± 8.5 years. All patients were randomized into two groups: the study group (n = 30, with the application of amiodarone hydrogel) and the control group (n = 30, without the application of amiodarone hydrogel). The dose of amiodarone in the hydrogel material was 60 mg for all patients. The heart rhythm was monitored during 5 days. The primary endpoint was the development of POAF. Secondary endpoints were: the dynamics of heart rate; the duration of the QT and PQ intervals; the development of blockades of the cardiac conduction system; as well as the dynamics of AST and ALT. According to the results of the experimental part, it was found that the method of the local epicardial delivery of amiodarone by the hydrogel material was safe. Hydrogel with amiodarone is effective for reducing the heart rate in the animal experiment in comparison to the control group and the group with the intravenous administration of the drug. The optimal dose of amiodarone in hydrogel was 1 mg per 1 kg. According to the results of the clinical part, it was found that the method of the local epicardial delivery of amiodarone as a hydrogel material proved its safety. Hydrogel with amiodarone at a dose of 60 mg was effective in preventing POAF in patients after coronary artery bypass grafting (CABG) operations in comparison to the control group (p < 0.001). The age and procedure of application of the amiodarone gel were significantly associated with POAF (p = 0.009 and p = 0.011, respectively). The use of hydrogel with amiodarone reduced the probability of developing POAF 18.9-fold. The method of the local epicardial delivery of amiodarone in the form of a hydrogel material is safe. The use of hydrogel with amiodarone after CABG reduced the probability of developing POAF.

2226The randomised study of epicardial application of hydrogel with amiodarone for prevention of postoperative atrial fibrillation in patients after coronary artery bypass grafting

Material and methods

We present an open prospective randomised study, in which 60 patients (47 male), mean age of 62±8,5 were included. Baseline clinical, laboratory and instrumental characteristics were similar in all patients. Patients didn't have any arrhythmic complains or previously registered AF. All patients underwent elective CABG and were randomised into two groups: Group #1 (n=30) - had the amiodarone-releasing hydrogel application before chest closure, and Group #2 (n=30) regular CABG surgery, no local application. We used 60 mg of amiodarone in hydrogel. This dose was experimentally determined during previously performed animal study. Heart rhythm control was monitored continuously during first 5 postoperative days and occasionally (mornings and evenings) the remaining days before the discharge. The local ethics committee approved this study design.

Results

The incidence of postoperative AF occurrence was significantly lower in Group #1: AF was registered in 3.3% cases versus 37% of patients from Group #2 (p<0.001). There was slight increase of PQ interval duration in Group #1 - 0.14 sec (0.12; 0.16), which however was significantly higher then in Group #2 - 0.12 (0.12; 0.14), (p<0.01). QRS and QT intervals were similar in both groups without significant difference.

There were no complications associated with the application procedure neither during postoperative period, such as AV block, infection or life-threatening situations.

According to 5 days ECG monitoring, the average heart rate in the Group #1 was 59 (52; 60) beats per min versus 69 beats per min (65; 75) in Group #2 (p<0.001). Temporary atrial or atrio-ventricular pacing used for correction of the heart rate if required in both groups. By the time of discharge none of the patients required permanent cardiac pacing. The length of stay in Group #1 was significantly shorter: 6 (6; 7) days versus 8 (8; 9) days (p<0,001).

Among all studied parameters, amiodarone-releasing hydrogel application and older age were statistically significant in postoperative AF occurrence (p<0.01). According to the Cox regression model amiodarone-releasing hydrogel application decreases the incidence of postoperative AF by 18,9 folds. The older age instead increases the incidence of postoperative AF by 1,2 folds.

Conclusions

The local epicardial amiodarone (60 mg) application in hydrogel before chest closure is a safe procedure. This approach showed it's effectiveness in AF prevention in patient undergoing elective CABG.

The Role of «Novel» Biomarkers of Systemic Inflammation in the Development of Early Hospital Events after Aortic Valve Replacement in Patients with Aortic Stenosis

INTRODUCTION

The pathogenesis of aortic stenosis includes the processes of chronic inflammation, calcification, lipid metabolism disorders, and congenital structural changes. The goal of our study was to determine the predictive value of novel biomarkers of systemic inflammation and some hematological indices based on the numbers of leukocytes and their subtypes in the development of early hospital medical conditions after mechanical aortic valve replacement in patients with aortic stenosis.

MATERIALS AND METHODS

This was a cohort study involving 363 patients who underwent surgical intervention for aortic valve pathology between 2014 and 2020. The following markers of systemic inflammation and hematological indices were studied: SIRI (Systemic Inflammation Response Index), SII (Systemic Inflammation Index), AISI (Aggregate Index of Systemic Inflammation), NLR (Neutrophil/Lymphocyte Ratio), PLR (Platelet/Lymphocyte Ratio), and MLR (Monocyte/Lymphocyte Ratio). Associations of the levels of these biomarkers and indices with the development of in-hospital death, acute kidney injury, postoperative atrial fibrillation, stroke/acute cerebrovascular accident, and bleeding were calculated.

RESULTS

According to an ROC analysis, an SIRI > 1.5 (p < 0.001), an SII > 718 (p = 0.002), an AISI > 593 (p < 0.001), an NLR > 2.48 (p < 0.001), a PLR > 132 (p = 0.004), and an MLR > 0.332 (p < 0.001) were statistically significantly associated with in-hospital death. Additionally, an SIRI > 1.5 (p < 0.001), an NLR > 2.8 (p < 0.001), and an MLR > 0.392 (p < 0.001) were associated with bleeding in the postoperative period. In a univariate logistic regression, SIRI, SII, AISI, and NLR were statistically significant independent factors associated with in-hospital death. In a multivariate logistic regression model, SIRI was the most powerful marker of systemic inflammation.

CONCLUSION

SIRI, SII, AISI, and NLR as novel biomarkers of systemic inflammation were associated with in-hospital mortality. Of all markers and indices of systemic inflammation in our study, SIRI was the strongest predictor of a poor outcome in the multivariate regression model.