RU2661735C1 - Method of optimal hydraulic dilatation in process of preparation of autovenous conduits in operations of coronary bypass surgery - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention relates to medicine, particularly to cardiovascular surgery. Intact venous conduit after isolation is cannulated and placed in a cold solution of heparinized blood. To the aortic canula, an adapter in the form of a tee is preliminarily connected through the Luer-port, to which an additional adapter of the “male-male” type is fixed to connect with the venous conduit. After cannulation of the aorta, the venous conduit through the adapters is connected to the aortic trunk. Artificial circulation with a perfusion pressure of 50–70 mm Hg is started. Art. Against the backdrop of artificial blood circulation, the tightness of the conduit is carefully checked, if necessary, additional vascular clips are superimposed. Venous conduit is connected to the aortic line through a system of adapters with perfusion hydraulic dilatation by aortic perfusion pressure.

EFFECT: method allows to exclude the traumatic effect of uncontrolled hydrodynamic pressure on the wall of a future venous shunt in the form of gross morphofunctional changes and thereby contributing to good patency of the shunts in the early postoperative period.

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Description

The invention relates to medicine, namely to cardiovascular surgery.

The large saphenous vein (BPV) is currently the most used conuditis for coronary artery bypass grafting due to its accessibility and ease of isolation. Despite this, the occlusion and stenosis of autovenous shunts in the short and long term after surgery is an important and unresolved problem in cardiac surgery. In the short term (within 1 month), the cause of obstruction is thrombotic occlusion of shunts, while in the long term, the dominant cause of obstruction of the shunts is the atherosclerotic process with subsequent occlusion, which occurs against the background of neointima hyperplasia [1]. A key role in the early dysfunction of autovenous shunts is played by structural and functional changes in the components of the wall of venous conuditis. This is due to the influence of many factors, such as the environment and storage temperature, the effect of hydrostatic pressure during hydraulic dilatation of the vein. Storage of venous autografts in warm saline leads to the death of endotheliocytes, while storage in warm blood is accompanied by moderate changes in the endothelium. The situation is different when storing conduits in cold environments: the integrity of the endothelium is preserved in both cases, although when stored in cold saline, swelling of the conduit wall was noted [2].

Equally important is the pressure pumped during the hydraulic dilatation of the conduit. The latter is used to check for leaks, detect damage and prevent spasm caused by trauma and hypoxia during surgery and the postoperative period. [3] With manual hydraulic dilation, which is used in routine practice, hydrostatic pressure is uncontrolled and usually exceeds 300 mmHg. Art.

High pressure leads to profound structural and functional changes. Vein expansion under pressure above 300 mmHg. Art. causes serious damage to the endothelium and swelling of the wall. The vascular endothelium is flattened and destroyed, deep damage to the intima and media is noted [2]. The death of endotheliocytes leads to the accumulation of fibrin on the surface of the wall, the adhesion of platelets and neutrophils.

Damage to the endothelium activates the external coagulation cascade by a tissue factor that is expressed by subendothelium [4].

The effect of high pressure also leads to a decrease in the activity of NO synthase with an increase in the tendency to platelet aggregation, and the expression of genes that control the proliferation and migration of smooth muscle cells is enhanced [3, 5]. The activity of NO synthase correlates with the patency of shunts in the early and long-term postoperative period.

Hydraulic dilation under pressure proportional to arterial blood pressure helps to maintain the integrity of all layers of the vascular wall, the biochemical characteristics and function of the endothelium and the media, and does not reduce the synthesis of NO [3].

High hydrodynamic pressure also leads to functional changes in the wall of the future shunt. Pressure injection up to 300 mm Hg. Art. and higher leads to a decrease in the contractile response to the action of phenylephrine and a depolarizing chloride solution, as well as to a decrease in the response to endothelium-dependent vasodilators (acetylcholine and bradykinin), no changes were observed at a pressure of 100 mmHg. Art. [6]. Thus, there is an urgent need to develop a method of controlled hydraulic dilatation of a vein.

In the analyzed patent and medical literature, an adequate prototype was not found.

The objective of the invention is to provide an easily reproducible, standardized method of hydraulic dilatation of a conduit, preserving the morphofunctional characteristics of a future venous shunt.

The problem is solved in that the intact venous conduit after cannulation is cannulated and placed in a cold solution of heparinized blood. An adapter in the form of a tee is pre-connected to the aortic cannula through the port of Luer, to which an additional adapter of the “papa-papa” type is fixed for connection with a venous conduit. After canalization of the aorta, the venous conduit through the adapters is connected to the aortic trunk. Artificial blood circulation is launched with perfusion pressure of 50-70 mm RT. Art. (average 65 mmHg), carefully check the tightness of the conduit, impose additional vascular clips.

New in the method proposed as an invention is the attachment of a venous conduit to the aortic line through a system of adapters with perfusion hydraulic dilatation with aortic perfusion pressure.

The proposed method eliminates the need for labor-intensive technologies for the physiological expansion of venous conduit.

The essential features characterizing the invention, showed in the claimed combination of new properties that are not explicitly derived from the prior art in this field and are not obvious to a specialist.

An identical set of features was not found in the study of patent and medical literature.

This invention can be used in medical practice to improve the quality and effectiveness of treatment.

The present invention meets the conditions of patentability "Novelty", "Inventive step", "Industrial applicability".

The invention will be understood from the following description and the accompanying drawings, where:

In FIG. 1 shows a method for optimal hydraulic dilatation during the preparation of autovenous conduits during coronary artery bypass surgery. Close-up:

1 - Aorta;

2 - Arterial highway IR;

3 - Adapter system;

4 - Cannulated venous conduit;

In FIG. 2 - A method for optimal hydraulic dilatation during the preparation of autovenous conduits during coronary artery bypass surgery. Overview shot:

1 - Aorta;

2 - Arterial highway IR;

3 - Adapter system;

4 - Cannulated venous conduit;

In FIG. 3 is a morphological picture of changes in the wall of a vessel subjected to manual hydraulic dilation. Marked thinning of the vessel wall

In FIG. 4 is a morphological picture of changes in the wall of a vessel subjected to manual hydraulic dilation. Multiple microfractures in all shells.

In FIG. 5 is a morphological picture of changes in the vessel wall during perfusion hydraulic dilation. The layers of the vessel wall are saved.

In FIG. 6 - Results of a biophysical study. The response of the smooth muscle apparatus of the vein wall to a depolarizing solution of potassium chloride and phenylephrine:

MN - mechanical stress;

PE - phenylephrine;

mm - millimole;

μM - micromol;

KCl - potassium chloride;

NaCl - sodium chloride;

In FIG. 7 - Results of a biophysical study. The response of the smooth muscle apparatus of the vein wall to sodium nitroprusside:

MN - mechanical stress;

PE - phenylephrine;

mm - millimole;

μM - micromol;

KCl - potassium chloride;

NaCl - sodium chloride;

NP - sodium nitroprusside:

The method is as follows.

Deliver the patient to the operating room. Induction anesthesia, intubation, and catheterization of the central vein and radial artery are performed on the left. Under conditions of neuroleptanalgesia, an antiseptic solution is treated and the surgical field is limited. Cut the skin, subcutaneous tissue, perform median sternotomy. A wide T-shaped pericardiotomy is performed. After opening the pericardium, a heparin solution is administered (at the rate of 300 PIECES per 1 kg of the patient's body weight).

Simultaneously with an incision on the chest, excretion of the large saphenous vein begins with an incision in the skin and subcutaneous tissue throughout the entire length of the conduit. A vein is extracted from the surrounding tissues with maximum preservation of paravasal tissue.

After opening the pericardium, purse string sutures are applied and the cardiopulmonary bypass is connected, the connection option is selected in accordance with the planned volume of operation, while the design of the adapters is pre-connected to the aortic cannula according to the above scheme. The initiation of cardiopulmonary bypass is initiated. After this, a cannulated autologin joins the port of the adapter, the port opens (Fig. 1 and 2). The residual thrombotic masses are washed away with blood. Then, a vascular clamp of the Bulldog type is superimposed on the distal end of the vein from the aortic trunk. The perfusion hydraulic dilatation of the vein begins under the influence of perfusion pressure.

Vienna is carefully inspected, the necessary sections are clipped. After that, the port closes, the venous conduit is disconnected.

Perform transverse clamping of the aorta, and then begin antegrade cardioplegia with a solution of Custodiol in the aortic root. The main stage begins. Distal anastomoses are applied to the affected coronary arteries. The transverse clamp is removed from the aorta. After restoration of cardiac activity, lateral aortic clamping is performed with the subsequent formation of proximal anastomoses to the aorta. Artificial circulation stops, after which a flowmetric assessment of blood flow by shunts is performed. Decanulation, hemostasis. Drainage of the pericardial cavity and anterior mediastinum, if necessary, pleural cavities. Next, sternal metal osteosynthesis is performed by wire ligatures, after which soft tissues are sutured in layers. The operation ends with an aseptic dressing.

Clinical example

Patient S., 59 years old. Diagnosis: ischemic heart disease. Angina pectoris, FC III. Atherosclerosis of the coronary arteries (anterior descending artery, subtotal stenosis in pr / 3, I diagonal artery at the mouth of stenosis 75%, envelope artery in cp / 3 75%, right coronary artery 75%). NK I, FC II by NYHA.

Echocardiography before surgery: violations of global and local contractility, valve pathology not detected.

Ultrasound scanning of veins of the lower extremities: veins are passable, not dilated, compressivity is preserved.

04/06/17 - coronary artery aortocoronary and mammarocoronary artery bypass grafting was performed. Intraoperative was used hydraulic dilatation of the conduit by the proposed method. A flowmetric assessment of blood flow by shunts was performed: the volumetric velocity corresponds to the diameter of the coronary artery, the pulsatile index is less than 5, the diastolic filling is more than 65%. The operation is completed as usual.

Fragments of the vein remaining after the operation are subjected to manual hydraulic dilation with a syringe with heparinized blood. An adapter according to the type of tee connected to the cannula of the autovein is connected via a highway with a monometric sensor (the pressure value was 320 mmHg).

Samples of perfusion and manual uncontrolled hydraulic dilatation veins were investigated. A morphological and biophysical assessment of both expansion methods was carried out.

The postoperative period was uneventful, angina pectoris return, no perioperative heart attack. No complications from the lower extremities were noted, wound healing by primary intention. On the 18th day after the operation, the patient was discharged from the hospital with an improvement in the course of the current disease.

Morphological changes in the walls of the veins. Manual hydraulic dilation is characterized by thinning of the vessel wall (Fig. 3), multiple micro-fractures in all shells (Fig. 4). For perfusion dilatation, the preservation of the layers of the vessel wall is characteristic, damage caused by the expansion method is not detected (Fig. 5).

The functional state of the veins. The study of contractile activity of smooth muscles was performed by mechanography. The amplitude of the contractile responses was calculated as a percentage of the amplitude of the hyperkali contraction (equimolar substitution of 30 mM NaCl per KCl) and / or phenylephrine-induced contraction, which was taken as 100%. The ability of smooth myocytes to relax was evaluated by adding sodium nitroprusside to the shortened vein segments.

The mechanographic method showed that hyperpotassium solution causes an increase in the contraction of the smooth muscle preparation with both methods of dilatation. The amplitude of contraction is higher in fragments of veins subjected to perfusion-hydraulic dilatation. Vein fragments subjected to manual hydraulic dilatation are less sensitive to phenylephrine α-adrenergic agonist, the reduction amplitude is much lower (Fig. 6). Sodium nitroprusside causes a complete decrease in the tension of the smooth muscle preparation, reduced by both phenylephrine and hyperpotassium solution both during perfusion dilation and manual dilation (Fig. 7).

The method proposed as an invention was tested on 30 patients with exertional angina and eliminates the traumatic effect of uncontrolled hydrodynamic pressure on the wall of the future venous shunt in the form of gross morphofunctional changes. This makes it possible to exclude the negative effect of high hydrostatic pressure on the further functioning of the autovenous conduit. The proposed method is easily reproducible.

Bibliography

1. Motwani JG, Topol EJ. Aortocoronary saphenous vein graft disease: pathogenesis, predisposition, and prevention. Circulation. 1998 Mar 10; 97 (9): 916-31. Review

2. Gundry SR, Jones M, Ishihara T, Ferrans VJ. Optimal preparation techniques for human saphenous vein grafts. Surgery 1980 Dec; 88 (6): 785-94.

3. Okon EB, Millar MJ, Crowley CM, Bashir JG, Cook RC, Hsiang YN, McManus B, van Breemen C. Effect of moderate pressure distention on the human saphenous vein vasomotor function. Ann Thorac Surg. 2004 Jan; 77 (l): 108-14.

4. Verrier ED, Boyle EM Jr. Endothelial cell injury in cardiovascular surgery. Ann Thorac Surg. 1996 Sep; 62 (3): 915-22. Review

Alfonso MS, Bodin L, Souza DS. Retaining perivascular tissue of human saphenous vein grafts protects against surgical and distension-induced damage and preserves endothelial nitric oxide synthase and nitric oxide synthase activity. J Thorac Cardiovasc Surg. 2009 Aug; 138(2):334-40. doi: 10.1016/j.jtcvs. 2008.11.060. Epub 2009 Mar 10.5. Dashwood MR, Savage K, Tsui JC, Dooley A, Shaw SG,

Alfonso MS, Bodin L, Souza DS. Retaining perivascular tissue of human saphenous vein grafts protects against surgical and distension-induced damage and preserves endothelial nitric oxide synthase and nitric oxide synthase activity. J Thorac Cardiovasc Surg. 2009 Aug; 138 (2): 334-40. doi: 10.1016 / j.jtcvs. 2008.11.060. Epub 2009 Mar 10.

6. Chester AH. Buttery LD, Borland JA, Springall DR. Rothery S, Severs NJ, Polak JM, Yacoub MH. Structural, biochemical and functional effects of distendingpressure in the human saphenous vein: implications for bypass grafting. Coron. Artery Dis. 1998; 9 (2-3): 143-51.

Claims (1)

The method of hydraulic dilatation in the preparation of autovenous conduits during coronary bypass operations, characterized in that the intact venous conduit after cannulation is cannulated and placed in a cold solution of heparinized blood, then the conduit is connected to the aortic trunk to connect the conduit with the aortic trunk to the aortic cannula beforehand Luer is attached with an adapter in the form of a tee, to which an additional adapter of the “father-father” type is fixed, after cannulation of the aor s venous conduit through a data adapter connected to the aortic trunk, then artificial circulation trigger with a perfusion pressure of 50-70 mm Hg. Art., and on the distal from the aortic trunk end of the autovenous conduit, a vascular clamp is applied and the conduit is checked for leaks.

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