Efficiency of myocardial protection using blood cardioplegia in cardiac surgery

Proven effectiveness of heart protection for up to 2 hours with a single administration of Normacor

Yavorovsky A.G., Komarov R.N., Aliyev V.A., Puzenko D.V., Bagdasarov P.S., Neizvestnykh D.P., No I.I.

View PDF

Clinical center: First Moscow State Medical University named after I.M. Sechenov, Ministry of Health of Russia (Moscow)
Study design: Experimental study under intentional anemia conditions in an animal model

Purpose of the study

Determination of the maximum safe time for aortic clamping when using the cardioplegic solution Normacor® as a myocardial protector.

The study was conducted on 5 mini-pigs weighing from 31 to 37 kg.

The surgeries were performed using cardiopulmonary bypass. A mixture of Normacor No. 1 cardioplegic solution (400 ml) and oxygenated blood was administered in a 1:2 ratio.

Every 30 minutes (up to the 180th minute), a myocardial biopsy was taken for further examination of histological and histochemical parameters.

During the operation, conditions of intentional anemia were created with hematocrit values of 15-17.

Experimental surgery on a mini-pig using cardiopulmonary bypass

Section

Histological examination

According to histological examination, changes characteristic of ischemic myocardial damage, under conditions of intentional anemia, began to appear after the 120th minute of aortic clamping and administration of a single dose of Normacor® and reached a maximum by the 180th minute.

Left ventricular myocardium at different stages of surgery, stained with hematoxylin and eosin.

Left ventricular myocardium at 120 minutes, hematoxylin and eosin staining.

Section

120 minutes - reversible degenerative changes in cardiomyocytes

cytoplasm lysis
stromal edema
diapedesis
foci of coagulation

Section

Immunohistochemical study

Succinate dehydrogenase (SDH) concentrations began to decline after the 120th minute (from 6 points at baseline to 4 points) and reached 2 points by the 180th minute. Hypoxia-inducible factor levels (2 points at baseline) decreased by the 30th minute (1.4 points), increased until the 150th minute (4 points), and decreased almost to baseline by the 180th minute (2-4 points).

SDH content — 6 points at baseline (6-point scale). Van Gieson staining.

Hypoxia-inducible factor — 2 points at baseline (6-point scale). Van Gieson staining.

Conclusion

The first morphological signs of ischemia were detected 120 minutes after aortic clamping and a single administration of Normacor.

This means that Normacor® provides effective cardiac protection for 120 minutes from the moment of a single administration of cardioplegia following aortic cross-clamping. Therefore, a single dose of the solution is sufficient for most cardiac surgeries.