RU2335290C2 - Method of myocardium protection during operations on heart - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to cardiosurgery and concerns myocardium protection during operations on heart. For this purpose cardioplegic solution based on autoblood with ratio of autoblood and crystalloid component 4:1 is introduced into coronary vessels. Solution is cooled to 10-12°C and introduced in steps: 1 step 200 ml, 2 step - 100 ml, 3 and further steps - 15 ml. Each further step is started after application of distal coronary anastomosis, and/or if myocardium temperature rises higher than 15°C, and/or recommencement of electromechanical activity of myocardium. Before removal of clamp from aorta heat blood reperfusion of myocardium with phosphocreatin preparations is performed. Cardioplegia is performed in conditions of normothermal perfusion.

EFFECT: ensuring spontaneous recovery of rhythm of heart contractions, reduction of post-operation period and reduction of frequency of complications development during and after operation.

5 tbl, 5 dwg

Description

The invention relates to the field of surgery, in particular to cardiac surgery and can be used for heart surgery.

A known method of protecting myocardium during heart surgery is blood-based cold cardioplegia (HKKP) by perfusion of the coronary bed with chilled heparinized blood, supplemented by local cooling of the heart with fine-crushed ice and general hypothermic perfusion (Buckberg GD Update on current techniques of myocardial protection. // Ann. Thorac. Surg. - 1995. - Vol.60, No. 3. - P.805-814).

The disadvantages of this method are: the danger of the formation of microtrombi of the coronary bed, damage to the intima of the coronary arteries, due to the low temperature of the injected cardioplegic solution (4 ° C). Also, with local cooling of the heart and general hypothermia, blood viscosity increases, microcirculation worsens, enzyme activity decreases, which generally increases the duration of the recovery period.

The purpose of the invention is the elimination of the negative effects of hypothermia and the reduction of the recovery period of patients after heart surgery.

The goal is achieved by the fact that during cardioplegia (CP) the ratio of blood and crystalloid component is 4: 1, the solution is cooled at least 10 ° C, the phased introduction of the solution: 1 stage 200 ml, 2 stage 100 ml, 3 and then 75 ml stages , the beginning of each subsequent stage is the completion of the application of the distal coronary anastomosis, the increase in myocardial temperature above 15 ° C or the resumption of the electromechanical activity of the myocardium (but not more than after 15-20 minutes), conduct thermal blood reperfusion of the myocardium before removing the clamp from the aorta from the prep with phosphocreatine, cardioplegia is performed under normothermic perfusion.

The method is implemented as follows:

1. Blood is drawn by the pump from the cardiotome reservoir, then it is mixed with a crystalloid solution using a tee connector (the flow is regulated by the pump segment), the resulting mixture of blood and crystalloid is fed into a heat exchanger, and then into cardioplegic cannulas. The ratio of the performance of the pump segments for blood supply and crystalloid is set as 4: 1.

2. The introduction of a cardioplegic solution is carried out in the aortic root, immediately after applying a clamp to the aorta in an amount under a pressure of 100-130 mm Hg to overcome the resistance of a contracting heart. The volume of crystalloid solution according to cardioplegia sessions: 1 session 200 ml, 2 session 100 ml, 3 and further - 75 ml each. The volume of the last portion of the cardioplegic solution (CRC) and the K ⁺ content in it are determined taking into account the potassium content in the perfusate, the presence of ECG activity, as well as the estimated time the surgeon finishes the main stage of the operation.

3. Combined administration of a cardioplegic solution is necessary, while for the induction of cardiac arrest, administration of the solution is only antegrade, the retrograde route of administration of CRC is used in repeated sessions of cardioplegia. Repeated infusions of the cardioplegic mixture are carried out after each formed distal coronary anastomosis, when the myocardial temperature rises above 15 ° C or when electromechanical activity is resumed (but not more than after 15-20 minutes).

4. To prevent the occurrence of “oxygen and heat shock” to the cold anoxized myocardium and reperfusion injuries, it is necessary to inject a warm cardioplegic solution based on blood with the addition of phosphocreatine preparations immediately before removing the clamp from the aorta.

5. The duration of the introduction of CRC depends on the method of administration (antetrograde), the session of cardioplegia and resistance in the cardioplegic line and averaged 1.8 minutes.

6. HKKP was carried out in the conditions of normothermic perfusion (t ° C in the esophagus 34-35 ° C).

We analyzed the results of clinical observations in 110 patients with coronary artery disease, operated on an open heart using various methods of myocardial protection, for the period from January 2000 to May 2004 in the clinic of cardiovascular surgery named after P.A. Kupriyanov of the Military Medical Academy named after S.M. Kirov.

All patients, depending on the option of intraoperative myocardial protection, are divided into 3 groups (table 1).

Group 1 - 40 patients who underwent open heart surgery under the conditions of pharmacological cold crystalloid cardioplegia (according to the method of VNTSH - Konstantinov B.A., 1981) and hypothermic perfusion.

Group 2 - 40 patients who underwent open heart surgery under conditions of intermittent thermal blood potassium cardioplegia (according to the method of Calafiore A.M. et al., 1995) and normothermic perfusion.

Group 3 - 30 patients who underwent open heart surgery under conditions of cold blood potassium cardioplegia (according to the method of Buckberg G.D. et al., 1995) and normothermic perfusion (“warm body-cold heart”).

Differences between groups by age, sex and body weight were not significant (p> 0.05) (Table 1).

Table 1 Brief characteristics of patients Sign 1 group (n = 40) 2 group (n = 40) 3 group (n = 30) Abs. % Abs. % Abs. % Floor: men 40 one hundred 39 97.5 28 93.3 women 0 0 one 2,5 2 6.7 Age 54.8 ± 1.2 53.4 ± 1.4 57.3 ± 1.7 Body mass 82.2 ± 1.5 84.8 ± 1.4 83.4 ± 2.1

The severity of the initial condition of the patients was evaluated by the following signs:

1) functional class (FC) of angina pectoris according to the classification of the Canadian Heart and Vascular Association (CCS);

2) the initial severity of the operated patients according to the New York Association of Cardiology (NYHA);

3) circulatory failure (NK) according to the classification of M.D. Strazhesko and V.Kh. Vasilenko, 1935;

4) a history and number of myocardial infarction;

5) the presence of postinfarction aneurysm of the left ventricle;

6) ejection fraction of the left ventricle (EF);

7) the degree of damage to the coronary bed according to coronarography;

8) the presence of myocardial hypertrophy;

9) the presence of concomitant pathology.

The results of the preoperative examination on these grounds are presented in table 2 and figure 1.

table 2 Clinical characteristics of patients Sign 1 group (n = 40) FHKP 2 group (n = 40) ITKKP 3 group (n = 30) HKKP Abs. % Abs. % Abs. % Angina II FC 2 5 2 5 one 3.3 III FC 22 55 22 55 fifteen fifty IV FC fourteen 32,5 12 thirty 13 43.3 unstable 2 5 four 10 one 3.3 Myocardial infarction 29th 72.5 28 70 21 70 Repeated MI 10 25 6 fifteen 9 thirty Rhythm disturbances 8 twenty 8 twenty 7 23.3 NK 0 degree four 10 5 12.5 2 6.7 Tax Code I degree 16 40 eighteen 45 fourteen 46.6 NK IIa degree twenty fifty 17 42.5 fourteen 46.6

From the data presented in table 2, it can be seen that for all the signs characterizing the severity of the initial state, patients of all groups had statistically insignificant differences.

The severity of the initial condition of the operated patients was also evaluated according to the generally accepted classification of the New York Association of Cardiology (NYHA). The vast majority of patients belonged to functional classes III and IV (Fig. 1): group 1 - 30 people (75%), group 2 - 30 people (75%), group 3 - 21 people (70%). Differences between groups are not statistically significant (p> 0.05).

As the data in Fig. 2 show, there are significant differences in the groups by the presence of fibrillation at the stage of induction of KP: in group III, fibrillation was registered in 3 (10%) cases, in group II - in 9 (22.5%) cases, while in group I in 18 (45%) cases. The lower incidence of fibrillation at the stage of induction of CP allows to significantly save the energy reserves of the myocardium and prevent its damage.

Table 3 presents a comparative description of the course of the post-occlusal period in the period from 0 to 60 minutes.

Table 3 The course of the recovery period in patients Recovery period FHKP (n = 40) ITK KP (n = 40) HKKP (n = 30) Abs. % Abs. % Abs. % Self-restoration of cardiac activity eighteen* 45 29th 72.5 twenty 66.7 through defibrillation 22 * 55 eleven 27.5 10 33.3 Paroxysmal ventricular tachycardia fourteen* 35 5 12.5 four 13.3 Application of temporary EX 8* twenty four 10 3 10 The use of cardiotonics (dopamine, etc.) to move away from IR thirty one hundred 29th 97.5 12* 40 The use of adrenaline for the departure from IR eighteen* 45 13 32,5 one 3.3 * - differences between groups are statistically significant (p <0.05)

As can be seen from the data presented, for most of the signs characterizing the course of the recovery period in the myocardium, there is a significant difference in the indicators in group I compared with groups II and III, and in the direction of deterioration.

After removing the clamp from the aorta, the main sign of effective myocardial protection is spontaneous recovery of heart contractions. In the first group of observations, where myocardial protection was carried out with a cold crystalloid solution, self-restoration of cardiac activity was observed only in 45% of patients. At the same time, in patients for whom myocardial protection was carried out with a cardioplegic solution based on blood, independent restoration of cardiac activity took place in more than half of the operated patients: in group II - in 72.5% of cases; in group III - in 66.7% of cases (figure 3). This indicates a more complete restoration of the cardiomyocyte at the time of removal of the clamp from the aorta.

** - differences between groups 1 and 2, 1 and 3 are statistically significant (p <0.01).

In order to study the intraoperative anti-ischemic myocardial protection, the inotropic support values were compared in groups with different cardioprotection methods during the first three days after surgery (Table 4).

Table 4 Doses of cardiotonics (according to dopamine) during the first three days after surgery, (μg / kg · min) Day after surgery FHKP (n = 40) ITK KP (n = 40) HKKP (n = 30) Abs. Abs. Abs. First 5.56 ± 0.37 * 4.92 ± 0.22 * 1.2 ± 0.28 * Second 4.99 ± 0.49 * 4.0 ± 0.25 * 0.73 ± 0.33 * Third 4.36 ± 0.55 * 2.17 ± 0.34 * 0.63 ± 0.3 * Total days 4.4 ± 0.3 * 3.3 ± 0.3 * 0.8 ± 0.2 * * - differences between groups are statistically significant (p <0.05)

As the data in Table 4 show, there are significant differences between all three groups, both in the dosage of inotropic drugs and in the duration of their use in the early postoperative period. At the same time, when using blood pharmacological cold cardioplegia as an intraoperative myocardial protection, the level of inotropic stimulation and its duration decreases on average by 4 times.

To assess the effectiveness of myocardial protection and the incidence of myocardial damage, we also used biochemical markers of cardiomyocyte death (Figs. 4-5).

Changes in the activity of total creatine phosphokinase (CPK) and its myocardial isoenzyme MB with high reliability indicate damage to myocardial cells (Korovkin B.V., 1965). A study of the activity of these enzymes in the dynamics of the disease allows us to judge the severity of myocardial infarction and the area of necrosis (Savchuk V.I. et al., 1980; Tsvetkovskaya G.A. et al., 2001).

The activity of total serum creatine phosphokinase in the first 5 days after coronary bypass surgery was significantly different in all the studied groups, which reflects the degree of general damage to muscle tissue that inevitably occurs during the main stage of the operation, although it is not a specific indicator of damage to the heart muscle. The smallest it was in group III, the largest - in group I (figure 4).

When assessing the performance of the KFK-MB isoenzyme (Fig. 5), a significantly smaller increase (2 times) was found in patients of groups III and II (p <0.05).

Postoperative complications occurred in 13 (32.5%) patients of the first group, in 9 (22.5%) patients of the second group and in 3 (10%) patients of the third group, the differences between the groups were significant (p <0.05). Data on the types of complications and the frequency of their development are presented in Table 5. There was a significantly lesser development of bleeding and purulent-septic complications in the postoperative period in groups using blood-based cardioplegia and normothermic perfusion (II and III), compared with the first group, where crystalloid cardioplegia and hypothermic perfusion were used to protect myocardium.

Table 5 Types and frequency of postoperative complications Sign FHKP (n = 40) ITK KP (n = 40) HKKP (n = 30) Abs. % Abs. % Abs. % Intraoperative myocardial infarction 7 * 17.5 four* 10 one* 3.3 Bleeding 5* 12.5 2 5 2 6.7 Purulent septic 3 * 7.5 one 2,5 - 0 Pneumothorax 2 5 3 7.5 one 3.3 Hyperthermia one 2,5 - 0 - 0 * - differences between groups are significant (p <0.05)

As can be seen from the data presented, there are significant differences between the groups for the development of myocardial infarction during surgery.

A more favorable course of the intraoperative period in groups of patients who used a blood-based cardioplegic solution also contributed to a smoother course of the immediate postoperative period. This is evidenced by:

1. Reduction in the duration of mechanical ventilation (mechanical ventilation) by 1.83 times in group II and 3.6 times in group III, which was 5.4 ± 0.9 and 10.8 ± 0.5 hours in the third and second groups, respectively, in comparison with the first group - 19.8 ± 1.3 hours (p <0.0001);

2. The length of stay of patients in the intensive care unit and intensive care unit, which was 2.5 ± 0.2 and 2.9 ± 0.2 days, respectively, in groups III and II, and in group I - 4.1 ± 0.3 days (p <0.001);

3. The duration of the postoperative period, which was: 16.5 ± 0.7 days in the third group, 20.1 ± 0.7 days in the second group, compared with the first group - 23.9 ± 1.3 days (p < 0.05).

The number of adverse outcomes after coronary bypass surgery was significantly less in the groups using blood-based cardioplegia: in the second group, 3 patients died (7.5%), in the third group, one patient died (3.3%), while in the first group, mortality amounted to 12.5% (5 patients). The differences between all groups are significant (p <0.05).

Thus, our proposed method of myocardial protection, used in heart surgery in the 3rd group of patients, leads to the following.

- To reduce the incidence of fibrillation at the stage of cardioplegia induction by 1.2 times.

- An increase in the frequency of spontaneous rhythm recovery after aortic release.

- Reducing the need for inotropic stimulation to correct the syndrome of small cardiac output after surgery by 3.2 times.

- Less pronounced metabolic changes in the myocardium and blood.

- The reduction in the postoperative period, which amounted to: 16.5 ± 0.7 days in the group where the proposed method of myocardial protection was used, against 20.1 ± 0.7 days in the control group (p <0.05).

- Reducing the incidence of postoperative complications and mortality (1.7 times).

Claims (1)

A method of protecting the myocardium during cardiac surgery by introducing a cooled cardioplegic solution based on autoblood into the coronary vessels, characterized in that the solution is injected into the coronary vessels at a 4: 1 ratio of autoblood and crystalloid component, the solution is cooled to 10-12 ° C, and the solution is driven in stages: 1 stage 200 ml, 2 stage - 100 ml, 3 and further stages of 75 ml, each subsequent stage begins after application of the distal coronary anastomosis, and / or when the myocardial temperature rises above 15 ° C, and / or the resumption of electromechanical myocardial activity, and before removing the clamp from the aorta, thermal blood reperfusion of the myocardium with phosphocreatine preparations is carried out, cardioplegia is performed under conditions of normothermic perfusion.

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