RU2696057C2 - Method of performing norwood operation, vascular homograft and method for producing vascular homograft - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: group of inventions refers to medicine, namely to cardiosurgery. Median sternomia is performed. Pericardium is opened. Aorta, arch and its branches, open arterial duct and pulmonary trunk are mobilized. Pulmonary trunk is injected with an aortic cannula and a right atrium with a venous cannula. Blood circulation is stopped. Right atrium is opened. Interatrial septum is excised. Pulmonary trunk is bifurcated below the bifurcation. Holes in the pulmonary artery are sutured from the arterial duct. Aorta is reconstructed using a flap cut from a pulmonary artery flap so that a bend in the area of the pulmonary artery transition into the pulmonary artery branch is the lower aortic arch wall. Vascular homograft created from a pulmonary artery flap in the form of a tube with a valve located in the middle one-third of the tube is implanted between the hole in the bifurcation of the pulmonary artery and the opening in the wall of the right ventricle. Above operation is performed by means of a vascular homograft represented in the form of a tube, which is created from a flap of the pulmonary artery and contains a bivalve semilunar valve made of the native flap of the pulmonary artery located in the middle one-third of the tube. Vascular homograft is produced as follows. Pulmonary artery flap is cut along. Flap is cut out of it in the form of a strip with expansion on one of the ends and a leaf of the native semilunar valve. Then, the leaf fragment of the native semilunar valve in the lower one-third of the strip is fixed to the edges and the middle of the flap between the fixation points with a suture, which describes two arcs connecting the end points and the fixation point in the middle so that two pockets are connected. Thereafter, flap ends are sutured together to form a tube with a two-wing valve diverging on an upper end.

EFFECT: group of inventions enables to prevent haemorrhage from the jabs when creating an anastomosis, sweating plasma through the wall of the prosthesis, provide unidirectional blood movement, lower risk of such complications as false aneurysm, thrombosis, neointimal proliferation, to select an optimal size of homograft, and also to create a proximal anastomosis between a homograft and a right ventricle, with complete or almost complete excision of a muscular board, which will prevent the development of calcinosis in this area and thereby increase the service life of the homograft.

5 cl, 2 tbl, 2 ex, 1 dwg

Description

The invention relates to medicine, namely to cardiac surgery, and more specifically to the technology of Norwood surgery in newborns with hypoplastic left heart and homografts used for prosthetics of the cardiovascular system.

Left heart hypoplasia syndrome (GLOS) is a combined congenital heart disease (CHD), which includes: stenosis or atresia of the mitral and aortic valves, left ventricular hypoplasia (LV), ascending aortic hypoplasia, aortic coarctation (CA), open ductus arteriosus. It refers to common heart defects and is observed in almost 20% of children with CHD. Moreover, this syndrome is the main cause of death in up to 25% of newborns and children with CHD in the first weeks of life, of which 38% of children die in the first 48 hours, and 72% - during the 1st week of life (Medicus.ru: http: //www.medicus.ru/handbo-ok/disease/sindrom-gipoplazii-levyh-otdelov-serdca. phtml).

For the treatment of pathology, Norwood’s operation (OH) has been proposed, which can simultaneously eliminate obstruction of the systemic circulation and excess pulmonary blood flow. After its completion, an operation is then performed to create an upper bi-directional cavapulmonary anastomosis, and then Fontaine’s operation. Moreover, the effectiveness of treatment of the patient is largely determined by the results achieved during the Norwood operation.

At the same time, there is currently no consensus on the optimal execution technique and methods for ensuring the Norwood operation (http://www.fesmu.ru/elib/Article.aspx?id=199729). As a rule, the classical stepwise method developed by W. Norwood is used for the treatment of GHSV (Medicus.ru: http://www.medicus.ru/hand-book/di-sease/sindrom-gipoplazii-levyh-otdelov-serdca.ph .tml), which includes the following steps.

Stage 1. Perform a median sternotomy, open the pericardium and conduct extensive mobilization of the aorta, the arch and its branches, the open arterial duct and pulmonary trunk. The pulmonary trunk of the aortic cannula and the right atrium are cannulated and perfusion is performed to cool the patient to a temperature of 18-20 ° C. The brachiocephalic arteries are pinched with turnstiles, stop perfusion and open the right atrium. Excised the entire interatrial septum. The pulmonary trunk is cut off immediately below the bifurcation and the hole is closed with a patch.

The open arterial duct is cut off from the descending aorta, the proximal end is ligated. The aorta is dissected along the entire available length - from the root to the descending section. The cut section of the pulmonary homograft is sewn into the formed incision to create a sufficiently wide lumen of the arc and the beginning of the ascending aorta. At this stage of the operation, it is recommended to use for implantation of the aortic arch and extra-cardiac valve-containing conduit implantation between the right ventricle and pulmonary artery bifurcation using a 5 mm diameter pulmonary homograft section containing a bicuspid lunate valve.

Stage 2. 6-8 months after the completion of the first stage, the previously implanted homograft is bandaged between the right ventricle and the pulmonary artery. Fully, to the roots of the lungs, the pulmonary arteries are mobilized. The upper vena cava is cut off from the atrium. The hole in the right atrium is sutured, if necessary, increasing the atrial communication. Then, the upper edge of the right branch of the pulmonary artery is longitudinally dissected and the superior vena cava cut off from the atrium is sewn into the incision with a continuous suture.

Stage 3. After 2-3 years, an extracardiac conduit of polytetrafluoroethylene is implanted between the dissected inferior vena cava and the dissected inferior edge of the pulmonary artery.

The Gore-Tex vascular prosthesis (http://erber-yoga.net/gemo-dializ/blood119.htm) used in the Norwood operation according to the standard technique is a tube made of polytetrafluoroethylene.

The disadvantage of surgery using such vascular prostheses is increased bleeding from the injection site during the creation of an anastomosis, plasma sweating through the wall of the prosthesis, the absence of a locking mechanism in the prosthesis that provides unidirectional blood movement. In addition, when using it, there is a risk of complications such as a false aneurysm, thrombosis, and neointimal proliferation. In addition, problems arise due to the practical lack of homografts of such sizes and the need to create a proximal anastomosis between the homograft and the right ventricle, which is created by connecting the muscle “side” on the homograft (part of the heart muscle) with an opening in the right ventricle. At the same time, the muscular “side” is deprived of blood supply and calcifies rather quickly. As a result, the situation is complicated by the fact that valve flaps are fastened at this place, which are mainly a connective tissue matrix resistant to hypoxia, populated by myofibroblasts from the lumen of the vessel, and the attachment point to the wall has the largest mechanical load, then calcification muscle “side” significantly reduces the durability of the service of the homograft.

The above technology for the operation of Norwood is the closest analogue of the claimed group of inventions.

The technical problem solved by the author was to increase the effectiveness of surgical intervention.

The technical result during the Norwood operation was achieved in that in a method including median sternotomy, dissection of the pericardium, mobilization of the aorta, arch and its branches, open ductus arteriosus and pulmonary trunk, cannulation of the pulmonary trunk of the aortic cannula and the right atrium of the venous cannula, circulatory arrest , opening of the right atrium, excision of the interatrial septum, cutting off the pulmonary trunk below the bifurcation, suturing the opening in the pulmonary artery from the ductus arteriosus, dissection orths and its reconstruction in which reconstruction is carried out using a flap cut from the pulmonary homograph, so that the bend in the transition zone of the pulmonary artery trunk and the branch of the pulmonary artery of the homograft is the lower wall of the aortic arch, and between the hole in the pulmonary bifurcation and the hole in the wall a vascular homograft created from a pulmonary flap in the form of a tube with a valve located in the middle third of the tube is implanted in the right ventricle.

The excision of the muscle rim should be maximum, but not less than 80%, to ensure optimal conditions for engraftment of the homograft.

The proposed homograft, dubbed “Baby”, is a tube made of a pulmonary flap with an expanding upper end containing a bicuspid semilunar valve located in the lower third of the tube from the native pulmonary valve. The diameter of the tube intended, as a rule, for newborns is 4.5 ± 0.1 mm.

The homograft production scheme is shown in FIG. 1, where A is the cut-out fragments from the pulmonary homograft - flap and sash; B - fastening the valves to the flap; In - a flap with cusps of the lunar valve; G - homograph "Baby". The following notation is used: 1 - cut flap; 2 - cut flap of the lunar valve; 3 - a fragment of the sash used as a valve; 4 - fixation points of the sash; 5 - seam creating a tubular shape.

Homograph “Baby” for Norwood’s operation is obtained as follows: a flap is cut out of the pulmonary homograft in the form of a strip with an extension at one end 1 and the flap of the lunar valve 2, a fragment of the flap 3 in the lower third of the strip is fixed to the edges and the middle of the flap between the fixation points (points fixation 4) a mattress thread 8/0, which describes two arcs connecting the edge points and the fixation point in the middle, so that two pockets are created. Excess tissue of the sash is then cut off and the edges of the sash are fixed to the endothelium of the pulmonary flap with a second twisted suture and the suture 5 is sutured in such a way that a tube with a bicuspid valve is created, expanding at the upper end, which provides a wide anastomosis with bifurcation of the patient's pulmonary artery.

The cut flap has a length of 30 mm and a width of 16 mm with an extension at one end to 20 mm. The valve is placed at a distance of 10 mm from the narrow end of the flap. In this case, the valve flaps are sewn so that the imaginary chord along the edge of the half moon between the vertices is slightly shortened to ensure effective “floating” of the valves, providing further good closure (cooptation) of the valves.

As a result of applying the method, anastomoses (connections) are created between the exit tract of the right ventricle and bifurcation of the pulmonary artery with the vascular tissue of the Baby. In this case, the vascular tissue of the pulmonary artery with the growth of the size of the heart is able to stretch, corresponding to a change in the size of the output tract. As a result, it is possible to increase the stability of the zone of attachment of the valve and increase the zone of co-optation (closing) of the valves.

An additional advantage of the proposed modification is the tightness of the created anastomoses.

In addition, if necessary, making an oblique cut in any plane, it is possible to artificially direct the homograft away from the midline to avoid compression by the sternum, to exclude narrowing, and also to prevent its coalescence with the sternum, which otherwise makes it difficult to isolate and bandage it, with repeated surgery.

Another advantage of using the inventive homograft is that, in contrast to the analogue, when sewn up a muscle rim 3-4 mm thick, a narrowing of the hole occurred, which in turn requires cutting a larger hole in the wall of the right ventricle, which leads to more damage to the contractile function myocardium in this zone, when using the inventive technology with complete or almost complete excision of the rim, damage to the right ventricle is minimal.

The advantages of the claimed group of inventions are illustrated by the following examples.

Example 1. Obtaining a homograph "Baby" was carried out as follows. A pulmonary artery fragment was used, 40 mm long and 16 mm wide, and a flap of a lunar lobe homogaft.

To create a bicuspid valve, a semilunar valve from the tissue of the semilunar valves of the pulmonary homograph was stitched along two arcs connecting in the area of the Arantz nodule (the first point), the second point of the arches was located at the edge of the pulmonary flap at points located at the intersection of the line perpendicular to the edge of the pulmonary flap and drawn through the first point. The seam was sewn with thread Prolen 7/0 and 8/0. The free edges along the tops of the commissures were sutured with a continuous seam on a beige of a given diameter. The diameter of the bouge used was determined by the mass of the patient. So, with a weight of up to 2.5 kg, the diameter of the bougie was 3.5 mm (3 patients), with a mass of 2.5 to 3.5 kg - 4.0 mm (9 patients), with a mass of more than 3.5 kg - 4.5 mm (5 patients). After implantation of a valve-containing homograft, an anastomosis of the pulmonary artery trunk with an aortic arch, previously enlarged due to the pulmonary homograft site, was performed.

The three-dimensional configuration of the pulmonary artery, its elasticity and radial elasticity ensured the reconstruction of the aortic arch without the formation of kinks.

The implantation of the section of the pulmonary artery and the valve-containing homograph “Baby” was performed to reconstruct the aortic arch between the right ventricle and pulmonary bifurcation to create pulmonary blood flow during Norwood's surgery.

The Kaplan-Meier method was used to assess survival in the early postoperative period after Norwood surgery and before the bidirectional cavopulmonary anastomosis operation. A risk analysis was carried out with a confidence interval of 95%. P <0.05 was considered significant.

In the cardiac surgery department, 17 patients were diagnosed with a diagnosis of left hypoplasia or a single ventricle with obstruction of the aortic arch, 11 of them were male and 6 were female. In 6 out of 17 patients, a restrictive atrial septal defect was detected, requiring balloon valvuloplasty in the first three days after admission to the hospital to stabilize hemodynamics.

Balloon valvuloplasty was performed in an angiographic laboratory under the control of an X-ray examination. Two patients after balloon valvuloplasty were prescribed dopamine at a dose of 10 μg / kg / min. According to preoperative ultrasound diagnostics, contractile myocardial function was preserved in 15 patients, amounting to 60-72%, in 2 patients myocardial contractile function was moderately reduced. Four patients had regurgitation on the I-II degree atrioventricular valve, which was also an indication for the use of a valve-containing conduit (GSSS).

Fifteen patients with left ventricular hypoplasia were diagnosed with stitching of the distal end of the “Baby” without additional patch in the area of pulmonary bifurcation, with a continuous single-row upholstery (Prolen 7/0) until cardioplegia was performed. For two patients, the vascular prosthesis was originally sewn into a patch from a bovine pericardium, and then the latter was sewn into a bifurcation. After the introduction of a cardioplegic solution, cardiac arrest and excision of the interatrial septum, a “gaping” through hole with a diameter of 4-6 mm was cut out in the intervascular zone of the output section of the right ventricle. The proximal anastomosis of the “Baby” with the wall of the right ventricle was created by a continuous twisting stitch (Prolene 7/0). For four patients, an anastomosis was superimposed on the epicardium of the right ventricle.

The age of patients ranged from 2 days to 271 days. Six of these patients were operated on after 30 days of birth, and 11 patients under 30 days of birth. The average age was 6.6 ± 1.8 days. The weight of patients ranged from 2.2 to 6.1 kg, averaging 3.5 ± 0.98 kg.

Survival is presented in table 1 according to the Kaplan-Meyer method.

The delayed closure of the sternum was performed on 2.8 ± 1.1 days and did not statistically differ from the closure of the sternum in patients after Norwood surgery without the use of homografts.

The average time of IV L was 7.5 ± 1.3 days. 14 (82.3%) patients received adrenaline. The duration of administration of adrenaline is 4.8 ± 0.47 days. The discharge from the hospital in this group of patients was 24.8 ± 6.1 days after surgery.

A statistical evaluation of the survival results of censored results by the Kaplan-Meier method was performed.

The cumulative survival rate for 9 months was 0.555. All patients before the second stage of correction take aspirin at a dose of 10 mg / kg per day once. 2 weeks before surgery, aspirin was canceled.

Surgical or early mortality was considered as mortality, which occurred after the Norwood procedure within 30 days or before discharge from the hospital and amounted to 11.8%. Mortality between stages in patients who underwent Norwood surgery and a valve-containing homograft was implanted was equal to zero before Glen's surgery. None of the patients needed to perform the second stage according to emergency indications in connection with increasing cyanosis. Mortality after Glen surgery (9 patients) was not in this group. One patient 5 months after Norwood's surgery had balloon aortic angioplasty. Cardiac catheterization was performed in all patients before Glen surgery. The results of catheterization of the heart chambers in patients undergoing Norwood surgery with a valve-containing homograph before Glen's operation are presented in Table 2.

Example 2. As a result of using the “Baby” homograft during the Norwood operation in 16 newborns, who installed the “Baby”, the operation was successful - the children got better. In the comparison group of 22 newborns who had a traditional homograft with a conduit without valve installed 12 died, 7 started having complications. During the second operation in these children using the "Baby", these children recovered.

Claims (5)

1. The method of Norwood's operation, including median sternotomy, opening of the pericardium, mobilization of the aorta, arch and its branches, open ductus arteriosus and pulmonary trunk, cannulation of the pulmonary trunk of the aortic cannula and right atrium by venous cannula, circulatory arrest, opening of the right atrium, and of the atrial septum, cutting off the pulmonary trunk below the bifurcation, suturing the opening in the pulmonary artery from the ductus arteriosus, dissection of the aorta and its reconstruction, characterized in that Aortic reconstruction is carried out using a flap cut from a pulmonary flap flap, so that the bend in the area of transition of the pulmonary artery trunk to the branch of the pulmonary artery turns out to be the lower wall of the aortic arch, and a vascular homograph is implanted between the hole in the bifurcation of the pulmonary artery and the hole in the wall of the right ventricle created from a pulmonary flap in the form of a tube with a valve located in the middle third of the tube. 2. The method according to p. 1, characterized in that the excision of the muscular rim is carried out not less than 80%. 3. Vascular homograph for the Norwood operation according to claim 1 in the form of a tube, characterized in that the tube is made of a pulmonary flap flap and contains a bicuspid lunate valve made of a native pulmonary valve, located in the middle third of the tube. 4. The vascular homograft according to claim 3, characterized in that the tube has a diameter of 4.5 ± 0.1 mm. 5. A method of obtaining a homograph for Norwood’s operation, namely, a pulmonary flap is cut lengthwise, a flap is cut out of it in the form of a strip with an extension at one end and the leaf of the native lunar valve, then a fragment of the leaf of the native lunar valve in the lower third of the strip is fixed to the edges and the middle of the flap between the fixation points by a thread that describes two arcs connecting the edge points and the fixation point in the middle so that two pockets are connected, after which the edges of the flap are stitched with expanding it at the upper end of the tube with a bicuspid valve.

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