RU2841530C1 - Method for relocation of papillary muscles in correction of ischemic mitral insufficiency - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention refers to medicine, namely cardiosurgery and concerns ischemic mitral insufficiency correction. Papillary muscles are relocated with the use of fixed-length polytetrafluoroethylene support sutures. Method includes anchoring to fibrous areas of posterior heads of papillary muscles of support sutures, length of which is equal to chord length of restrictive areas of posterior flap, with taking them to side of left atrium through fibrous ring of mitral valve (MV) in area of central part of posterior flap and fixation in corresponding sections support mitral ring.

EFFECT: method enables bringing both papillary muscles together and to a fibrous ring of the mitral valve, increases cusp mobility and a coaptation area thereof.

1 cl, 2 dwg, 2 ex

Description

The invention relates to the field of medicine, namely to cardiac surgery, and concerns the correction of ischemic mitral insufficiency.

Ischemic mitral regurgitation (IMR) is a common and serious complication of ischemic heart disease, leading to a significant increase in patient mortality. Regurgitation on the mitral valve (MV) occurs due to expansion of its fibrous ring, expansion of the left ventricular cavity, and dysfunction of the papillary muscles. Left ventricular (LV) remodeling leads to displacement of the papillary muscles, tension of the cusps, and loss of coaptation.

The first randomized studies comparing mitral valve replacement and reduction annuloplasty (i.e., narrowing of the mitral annulus only) showed a high rate of mitral regurgitation (MR) recurrence in the annuloplasty group in the medium-term follow-up. Moreover, the survival rate did not differ during 5-year follow-up. From this it was concluded that isolated reduction annuloplasty can be used only for a highly selective group of patients with IMN. In other cases, other options for plastic interventions or valve replacement are required.

There are known methods for correcting ischemic mitral regurgitation, including both reduction annuloplasty and interventions on subvalvular structures. These methods include two main ideas: bringing the papillary muscles closer to the fibrous ring (FR) of the mitral valve (MV) and to each other to improve mobility and coaptation of the MV leaflets. In total, the results of such operations showed a significant reduction in the frequency of MR recurrence when compared with isolated MV annuloplasty by 4 times after 3 years of observation.

[Harmel EK, Reichenspurner N, Girdauskas E. Subannular reconstruction in secondary mitral regurgitation: A me-ta-analysis. Heart. 2018;104(21):1783-1790. doi:10.1136/heartjnl-2017-312277].

The most promising of these methods is the method of papillary muscle relocation, which ensures the convergence of the papillary muscles with the mitral valve fibrous complex. Before implantation of the supporting mitral ring, the fibrous part of the papillary muscle heads is sutured with a polytetrafluoroethylene (PTFE) thread. Then, each PTFE thread is passed under the leaflet through the mitral valve fibrous complex behind the fibrous triangles of the heart (in the projection of segments P1 or P3) and through the synthetic annuloplasty ring. To achieve optimal coaptation of the leaflets, a hydrotest is performed - the LV is filled with a physiological solution and the tension of the PTFE threads is adjusted to the optimal value. If the tension is maintained and the coaptation of the mitral valve leaflets is insufficient, the PTFE thread is pulled up more, thereby bringing the papillary muscles closer to the mitral valve fibrous complex. In case of leaflet prolapse, on the contrary, the PTFE threads are loosened. The plastic surgery is completed if the valve function is satisfactory. PTFE threads are fixed in the corresponding sections of the support ring.

[Girdauskas E, Conradi L, Harmel EK, Reichenspurner N. Minimally invasive mitral valve annuloplasty with realignment of both papillary muscles for correction of type IIIb functional mitral regurgitation. Innovations (Phila) 2017;12:329-332].

The disadvantage of this method is: difficult determination of the optimal length of the threads (degree of convergence of the papillary muscles and the MC FC) by hydrotest, which does not always correspond to the physiological conditions of the left ventricle and MC function; both insufficient convergence of the papillary muscles with the MC and their excessive reduction to the MC are possible. This affects the success of MC plastic surgery and reduces the effectiveness of the method.

A method for correcting ischemic mitral regurgitation by bringing the papillary muscles closer together (ring+sling) is known. The essence of the operation is to implant a PTFE vascular prosthesis with a diameter of 4 mm into the LV. A loop is formed from the prosthesis, which is passed under the trabeculae around the base of each papillary muscle. Then the loop is tightened until the papillary muscles come closer together. Based on the results of the hydrotest, the degree of convergence of the papillary muscles is determined. The next stage is annuloplasty with a supporting mitral ring [Christos G Mihos, Romain Capoulade, Evin Yucel et al. Mitral Valve and Subvalvular Repair for Secondary Mitral Regurgitation: Rationale and Clinical Outcomes of the Papillary Muscle Sling. Cardiol Rev. 2018 Jan/Feb;26(l):22-28. doi: 10.1097/CRD.0000000000000168].

The disadvantages of this method are: difficult determination of the degree of convergence of the papillary muscles, possible disruption of the trophism of the papillary muscles and cutting of the ring through the muscle tissue. This can lead to an unsatisfactory result, especially in patients with mild cicatricial myocardial damage; with an increased volume of the LV, insufficient convergence of the papillary muscles with the FC of the MC is possible.

A method for treating mitral insufficiency is also known, which consists in suture plastic surgery of the subvalvular structures of the mitral valve by bringing both papillary muscles closer to the plane of the fibrous ring with simultaneous bringing the papillary muscles closer to each other with opposing U-shaped sutures. The papillary muscles are sutured to the fibrous ring of the mitral valve by forming neochords from polytetrafluoroethylene: from the anterior papillary muscle to the border of the posterior leaflet segments P1-P2; 2 from the posterior papillary muscle - to the border of the posterior leaflet segments P2-P3, while dosing the pulling of the converged papillary muscles to the fibrous ring of the valve, calculating the length of the formed neochords according to the formula.

[Patent of the Russian Federation No. 2374994, IPC A61 B 17/00, published 10.12.2009, Bulletin No. 34].

The disadvantages of this method are its complexity and trauma, as there is a high probability of suture cutting, especially in the area of the papillary muscles, and the formula for calculating the length of the threads uses parameters measured by echocardiography (EchoCG), which is an operator-dependent method.

The objective of the invention is to create a simple, accessible and effective method for relocation of papillary muscles during correction of ischemic mitral insufficiency, which allows improving the results of mitral valve plastic surgery, reducing the trauma of the operation performed, reducing the risk of suture cutting and reducing the duration of the operation itself.

The technical result consists in ensuring the availability and efficiency of the method.

This is achieved by the fact that in the claimed method of papillary muscle relocation during correction of ischemic mitral insufficiency, consisting in relocation of papillary muscles using fixed-length polytetrafluoroethylene support threads, characterized in that support threads are sutured to the fibrous areas of the posterior heads of the papillary muscles, the length of which is equal to the length of the chords of the restrictive areas of the posterior leaflet, with their withdrawal to the left atrium side through the fibrous ring of the mitral valve in the area of the central part of the posterior leaflet and fixation in the corresponding areas of the supporting mitral ring. Which ensures the convergence of both papillary muscles between themselves and the fibrous ring of the mitral valve, increases the mobility of the leaflets and the area of their coaptation.

The availability and effectiveness of the claimed method are achieved by measuring the length of the chords directly during the operation to accurately determine the length of the threads, which affects the success of mitral valve plastic surgery and reduces the duration of the operation.

Implementation of the method

Access to the mitral valve is obtained and its high-quality exposure is performed. Using a caliper, the length of the chords is measured from the heads of the papillary muscles that need to be pulled up. Two loops of PTFE thread are prepared in such a way that their length corresponds to the length of the corresponding chords. The loops are sutured to the heads of the posterior components of both papillary muscles on opposite pads. The mitral valve fibrous ring is sutured using the standard technique. After this, a separate polyfilament thread with atraumatic needles is inserted into each loop for subsequent fixation of the loop to the synthetic ring. The needles of the fixing threads are used to suture the native fibrous ring along its posterior semicircle with a tendency toward the center and/or to the site of greatest tension of the chordal apparatus, bringing the sutures through the PTFE towards the left atrium. Then, a semi-rigid supporting mitral ring of the appropriate size is implanted. The removed sutures are additionally fixed on the corresponding sections of the support ring by stitching it. After the plastic surgery, the valve function is determined by a hydrotest and the correct position of the fixed loops is verified.

The claimed method is illustrated by drawings.

Fig. 1. Schematic view of MK plastic surgery using the claimed method in lateral projection (A - before surgery, B - after surgery).

Fig. 2. Schematic view of the plastic surgery of the MC according to the claimed method in direct projection (A - before the operation, B - after the operation),

where 1 - mitral valve cusps, 2 - mitral chords, 3 - papillary muscles, 4 - supporting threads, 5 - supporting mitral ring, 7 - felt pad.

More than 30 surgical interventions were performed using the claimed method, as a result of which it was established that relocation of papillary muscles using loops of a fixed length corresponding to the length of native chords, with their removal in the central part of the posterior semicircle of the mitral valve, ensures sufficient coaptation of the mitral valve leaflets. In most patients, residual regurgitation was less than grade 1.

Examples of the method implementation

Clinical case 1

Patient G., 54 years old, with grade 3 ischemic mitral valve insufficiency and critical multivessel coronary artery disease is indicated for a combined operation: mitral valve plastic surgery and coronary artery bypass grafting.

Preoperative examination data.

Transesophageal echocardiography (TEE): Ectasia of the mitral valve ring, the leaflets are not compacted, restrictive tension of the posterior leaflet is noted (mainly the P2 segment) with an increase in the depth of coaptation to 1.1 cm. mitral valve ring: 4.1 x 4.6 cm. Mitral regurgitation: grade 3, vena contracta: 0.78 cm, PISA: 0.9 cm, with reflux into the left pulmonary veins.

Coronary angiography (CAG): right type of blood supply. Left coronary artery (LCA): with irregular contours; anterior descending artery (LDA): with irregular contours, 80% stenotic in the middle segment. Diagonal artery (DA): with irregular contours, 90% stenotic in the proximal third, 80% stenotic in the middle third. Circumflex artery (OA): with irregular contours. Obtuse marginal artery (OMA): with irregular contours. Right coronary artery (RCA): with irregular contours, subtotally stenotic in the middle segment, then occluded, post-occlusion sections are filled along intersystem collaterals; right ventricular branch is 70% stenotic in the proximal third, 70% stenotic in the middle third.

Progress of the operation.

Under endotracheal anesthesia (ETA), the great saphenous vein (GSV) of the left lower limb was isolated and prepared as an autograft. Longitudinal sternotomy was performed. The left internal thoracic artery (LITA) was isolated. Pericardiotomy. Aortic cannulation, separate cannulation of the vena cava. Vent into the upper right pulmonary vein (URPV). Cardioplegic needle in the aortic root. Artificial circulation (EC) and cooling of the patient were started. Transverse clamp on the aorta. Cold and drug cardioplegia with 2000 ml of Custodiol solution. Revisions revealed diffuse damage and calcification of the coronary arteries. Distal anastomoses of autoveins with the posterior interventricular branch (PIVB), diagonal artery (DA) were performed. An anastomosis of the LITA with the LAD was performed. Access to the MV was achieved through the right atrium (RA), interatrial septum (IAS) with transition to the roof of the left atrium (LA) (Guiraudon). During MV revision: MV insufficiency is noted due to expansion of the FC and tension of the papillary muscles. The length of the chords of the P1 and P2 segments of the posterior MV leaflet was measured, which was 16 and 18 mm, respectively. Two loops of 16 and 18 mm in length were prepared from PTFE threads. The loops were sutured to the fibrous areas of the posterior heads of the papillary muscles on opposing felt pads so that they were located under the posterior leaflet. The loops were pulled to the central part of the posterior semicircle of the FC of the MV with two sutures using Etibond thread. The ends of the threads were brought out towards the LA. An Edwards Physio #32 support ring was implanted in the mitral position using 13 U-shaped sutures. The threads pulling the loops to the central part of the posterior semicircle of the mitral valve are stitched through the support ring in the corresponding areas. Hydrotest: valve function is satisfactory. Suturing of the LA, IAS, and RA with a continuous locking suture. The clamp was removed from the aorta with prevention of air embolism. Cardiac activity was restored after defibrillation. Lateral pressing of the aorta. Two proximal anastomoses of autovenous bypass grafts with the aorta were performed. Reperfusion through the grafts. Decannulation. Hemostasis. Drainage of the anterior mediastinum and pericardial cavity. Electrodes for external pacemaker are sutured. Wire sutures on the sternum. Layer-by-layer suturing of the surgical wound. Aseptic dressings.

At the control echocardiography 7 days after the operation, we note minimal (0-1 degree) regurgitation on the MV.

Clinical case 2

Patient A., 54 years old, with angina pectoris of functional class 3, two-vessel coronary artery disease, grade 4 mitral regurgitation is indicated for coronary artery bypass grafting and reconstructive surgery on the mitral valve.

Preoperative examination data.

Transesophageal echocardiography (TEE): the leaflets are not compacted, restrictive tension of the posterior leaflet (due to the presence of the asynergy zone), pseudoprolapse of the anterior leaflet; the angle of the posterior leaflet is 57 degrees. MV ring: 3.3 x 4.3 cm (N = 2.3-3.5 cm). Mitral regurgitation: 4 degrees. PISA: 1.2 cm, eccentric regurgitant jet, directed under the anterior leaflet with reflux into the pulmonary veins.

Coronary angiography (CAG): Right blood supply. Subtotal stenosis of the LAD in the proximal section. Occlusion of the RCA in the proximal section. Progress of surgery.

Under ETN, the GSV of the left lower limb was isolated and prepared as an autograft. Longitudinal sternotomy was performed. The left ITA was isolated. Pericardiotomy. Aortic cannulation, separate cannulation of the vena cava. Start of cardiopulmonary bypass. Ventilation in the VPLV. Cardioplegic cannula in the aortic root. Transverse clamp on the aorta. Cold and drug antegrade cardioplegia with 2000 ml of Custodiol solution. Using an operating microscope, a distal anastomosis of the autovein with the RCA (d less than 1.5 mm) was performed. An anastomosis of the LVGA with the LAD (d = 1.5 mm) was performed. The left atrium was opened according to Carpentier. During revision of the MV, its insufficiency is noted due to prolapse of the A3 segment due to postinfarction elongation of the anterior head of the posteromedial muscle and tension of the P1 segment. Three loop neochords 18 mm long were sutured to the A3 segment, a 12 mm long support loop was sutured to the posterior head of the anterolateral muscle, which was brought out into the LA through the base of the posterior leaflet in the P1-P2 segment with Etibond thread. A Carbomedics Armuloflex 30 support half-ring was implanted with 10 U-shaped sutures with Etibond thread. The support loop is fixed to the half-ring in the corresponding area. Hydrotest: valve function is satisfactory. The LA was sutured with a continuous suture using Prolene thread. The clamp was removed from the aorta with prevention of air embolism. Cardiac activity was restored after defibrillation. Lateral aortic retraction. Proximal anastomosis of the autovein with the aorta is performed. Reperfusion via the bypass graft. The anastomoses are tight and patent. Stop CPB with moderate cardiotonic support. Intraoperative TEE shows satisfactory valve function. Decannulation. Hemostasis. Drainage of the anterior mediastinum, pericardial cavity, and left pleural cavity. Electrodes for external pacemaker are sutured. Osteosynthesis of the sternum. Layer-by-layer wound suturing. Aseptic dressings.

At the control echocardiography 7 days after the operation, we note minimal (grade 1) regurgitation on the MV.

Thus, the claimed method is feasible and reproducible, since it is based on measurements of the length of chords directly during the operation.

Claims (6)

A method of relocation of papillary muscles in the correction of ischemic mitral insufficiency, consisting of suture plastic surgery of the subvalvular structures of the mitral valve by bringing the papillary muscles closer to the plane of the fibrous ring with simultaneous bringing the papillary muscles closer to each other with opposing U-shaped sutures, suturing the papillary muscles to the fibrous ring of the mitral valve by forming neochords from polytetrafluoroethylene (PTFE), characterized in that 2 loops of PTFE thread corresponding to the length of the native chords in the stretched segments of the mitral valve leaflets are used as support threads; the supporting threads are sutured in a U-shape to the heads of the posterior papillary muscles on opposing pads, followed by suturing of the fibrous ring of the mitral valve; a separate polyfilament thread with atraumatic needles is passed through each loop for subsequent fixation of the loop to the synthetic ring; The native fibrous ring is stitched with fixing thread needles along its posterior semicircle with a tendency toward the place of greatest tension of the chordal apparatus, bringing the sutures through the fibrous ring toward the left atrium with subsequent implantation of a semi-rigid supporting mitral ring of the appropriate size, and the brought out sutures are additionally fixed on the corresponding sections of the supporting ring by stitching it.