[Hybrid grafts for aortic arch reconstruction: evolution and state of the art]. / Gibridnye protezy dlia rekonstruktsii dugi aorty: évoliutsiia i sovremennoe sostoianie.

The analysis of the gained experience in treatment of patients with pathology of the arch and descending portion of the aorta is suggestive that the 'frozen elephant trunk' technique is an effective and safe method. In this connection, there is an increasing need for universal hybrid devices characterized by ease of use and durability in various aortic pathologies. Discussed in the article is the state of the art of the technology of treatment of patient with aortic arch pathology by means of hybrid grafts, followed by comparative analysis of currently used vascular hybrid prostheses, and although none of the hybrid grafts available worldwide is either universal or ideal, the grafts for the 'frozen elephant trunk' procedure continue to be improved, which will inevitably lead to wide implementation of this technique.

[Quo vadimus? Fundamental problems of developing hybrid prostheses of thoracic aorta]. / Quo vadimus? Fundamental'nye problemy razrabotki gibridnykh protezov grudnoi aorty.

This article is a review briefly characterizing the state of the art of hybrid surgery of the thoracic aorta using the frozen elephant trunk technique worldwide and in Russia, also discussing unsolved problems of fundamental science, being key issues in creation of new models of hybrid prostheses of the thoracic aorta. The main attention is paid to the problem of radial stiffness of the stent-graft portion of the prosthesis. Performed is a detailed analysis of the factors influencing this characteristic of the sent graft: shape, size and number of cells of the stent element, thickness of the nitinol wire it is made of, method of edge connection, nitinol properties depending on the alloy grade and methods of thermoforming. It is shown that excessive stiffness leads to the development of d-SINE syndrome. This is followed by discussing the problem of optimal stiffness of stent grafts, based on the design of stent graft elements and elastic properties of the wall of the true channel of a dissecting aortic aneurysm. Also proposed is an approach to solving the problem of d-SINE, consisting in creation of conical stent grafts and/or a gradual decrease of radial stiffness of stent elements in the direction of the distal portion. Comprehensively addressed are disadvantages of the graft portion of the prosthesis, in 95% of items made of polyethylene terephthalate fiber: susceptibility to degradation associated with manufacturing defects and intraoperative microdamages, abrasive effect in the zone of contact with stent elements, partial postoperative hydrolysis and an inflammatory reaction to a foreign body, often being clinically pronounced. Also touched upon are certain aspects of creating hermetic coatings of the graft portion, with the use of vancomycin possessing low cytotoxicity as part of an antibacterial component being promising. As a whole, it is demonstrated that advances in creating a novel generation of hybrid prostheses should be associated with new approaches and materials, to be obtained at the junction of medicine and fundamental sciences.

Remote results of Florida Sleeve technique in patients with ascending aortic aneurysms and aortic insufficiency. / Otdalennye rezul'taty metodiki Florida Sleeve u patsientov s anevrizmoi voskhodiashchego otdela i aortal'noi nedostatochnost'iu.

AIM: The aim of our investigation was to assess the remote results of valve-sparing aortic root reimplantation into the graft (Florida Sleeve technique) compared with reimplantation of the aortic valve into the graft (David technique) during surgical correction of ascending aortic aneurysms accompanied by concomitant aortic insufficiency. PATIENTS AND METHODS: Our single-centre, blind, prospective, randomized study carried out from 2011 to 2015 included a total of 64 patients with ascending aortic aneurysms and aortic insufficiency. The patients were randomized into 2 groups: group I - aortic root reimplantation according to the Florida Sleeve technique (FS group) and group II - reimplantation of the aortic valve according to the T. David technique in David I modification (D group). The groups did not statistically differ by the baseline clinical profile. RESULTS: The overall 7-year survival for the FS group and D group amounted to 83% and 85.6%, respectively (p=0.98). Assessing the competing risks of mortality related to cardiovascular or other causes revealed no differences. Freedom from prosthetic repair of the aortic valve in the remote follow-up period amounted to 92.8% and 85.8% for the FS group and D group, respectively (p=0.4). According to the obtained findings, the technique of a valve-sparing operation is not a predictor of either lethality (RR 0.98 (95% CI 0.23-4.15), p=0.98) or prosthetic repair of the aortic valve (RR 2.03 (95% CI 0.40-14.63), p=0.40) in the remote period of follow up. RCONCLUSION: Aortic root reimplantation inside the prosthesis according to the Florida Sleeve technique makes it possible to simplify and accelerate the procedure of aortic root reconstruction in patients with aortic root aneurysms and concomitant aortic insufficiency, demonstrating long-term results comparable with those of the David technique.

[Hybrid approach to surgical treatment for a saccular thoracic aortic aneurysm]. / Gibridnyi podkhod pri khirurgicheskom lechenii meshotchatoi anevrizmy grudnoi aorty.

Presented herein is a clinical case report regarding hybrid surgical treatment for a saccular aneurysm of the aortic arch in a female patient. While undergoing a routine medical check-up she had been found to have fluorographic evidence strongly suggesting dilatation of the aortic thoracic portion. Based on the findings of further examination we determined the indications for surgical treatment of the thoracic portion of the aorta. The woman was subjected to reconstruction of the arch and the descending portion of the thoracic aorta according to the frozen elephant trunk technique.

[Use of extracorporeal membrane oxygenation for pulmonary haemorrhage after pulmonary endarterectomy]. / Primenenie ékstrakorporal'noi membrannoi oksigenatsii pri legochnom krovotechenii posle legochnoi éndarteréktomii.

Pulmonary haemorrhage is one of the most severe complications of pulmonary endarterectomy. To the most effective methods of combating this potentially fatal complication belongs extracorporeal membrane oxygenation (ECMO). In this article we describe a clinical case report regarding intraoperative use of central veno-arterial ECMO for pulmonary haemorrhage following thromboendarterectomy from the pulmonary arteries. According to the data of some authors, long-term ECMO support (for more than 4 days) may lead to such severe consequences as rethrombosis of pulmonary arteries and impairment of cerebral circulation. In our case we managed to avoid such complications, taking into consideration that the duration of ECMO amounted to 21 days. Resulting from the carried out comprehensive therapeutic measures by the time of discharge from hospital, a significant decrease in pulmonary artery pressure was achieved, with events of residual pulmonary hypertension.

[Florida sleeve operation in a patient with pronounced aortic root calcification]. / Operatsiia po metodike Florida Sleeve u patsienta s vyrazhennym kal'tsinozom kornia aorty.

Aneurysmatic dilatation of the aortic root and ascending portion of the aorta is one of the most complicated pathologies of the cardiovascular system. The 5-year survival rate does not exceed 13%. Especially difficult from the point of view of surgical reconstruction are variants of massive calcification of the aortic root. This article describes a case report concerning the Florida sleeve technique in a patient with diffuse calcification of the aortic root, involving the ostia of the coronary arteries. An important advantage of this type of intervention is technical simplicity consisting in no need for reimplantation of coronary artery ostia, thus decreasing the number of surgical manipulations and sutures on the aortic root, as well as reducing the risk of haemorrhage.

[Extra-anatomical bypass grafting of the thoracic aorta in a female patient with an infected pseudoaneurysm]. / Ékstraanatomicheskoe shuntirovanie grudnoi aorty u bol'noi s infitsirovannoi lozhnoi anevrizmoi.

Presented herein is the remote (more than 15-year follow up) result of successful surgical treatment of aortic coarctation complicated by septic aortitis and a false aneurysm of the anastomosis between the graft and the aortic arch. In 2002, after correction of aortic coarctation the woman was admitted to our Clinic with an incompetent proximal anastomosis and an infected aortic pseudoaneurysm. Taking into consideration the general and local septic process, repeat reconstruction of the thoracic aorta was impossible due to the risk for generalization of the infectious process and fatal complications. Therefore, the woman was subjected to extra-anatomical bypass grafting of the thoracic aorta with a synthetic graft from the ascending aorta to the infrarenal portion of the abdominal aorta in order to isolate the infection focus to be followed by removal thereof. The postoperative period turned out uneventful, with no complications. After 15 years, the woman was examined again, with her condition being stable. The findings of contrast-enhanced magnetic resonance imaging demonstrated complete patency of the extra-anatomical bypass graft. The carotid-subclavian anastomosis functioned well, without narrowed portions. No infectious complications after the carried out operations were observed. Using extra-anatomical bypass grafting with exclusion from circulation and removal of the infected portion of the aorta along with the graft is one of reliable variants of treatment for such a severe complication as an infected false aneurysm.

[Surgical treatment of chronic thromboembolic pulmonary hypertension]. / Khirurgicheskoe lechenie khronicheskoi tromboémbolicheskoi legochnoi gipertenzii.

Analysed herein are the results of pulmonary endarterectomy (PEA) performed in a total of 169 patients presenting with chronic thromboembolic pulmonary hypertension (CTEPH) at the National Medical Research Centre named after Academician E.N. Meshalkin over the period from 2004 to 2014. Pulmonary endarterectomy was carried out according to the standard technique in the conditions of assisted circulation with the use of hypothermia and circulatory arrest. The duration of follow up of patients after surgical treatment amounted to 10 years. During the in-hospital period (30 postoperative days) and in the remote period after the intervention (averagely amounting to 7.7±2.3 years), the following parameters were evaluated: the clinical status of the patients by means of the SF-36 Quality of Life Questionnaire, the 6-minute walk test, as well as the findings of instrumental methods of study, namely, transthoracic echocardiography, multispiral computed angiography of the pulmonary artery (PA), catheterization of the right portions of the heart, perfusion scintigraphy of the lungs. The obtained results demonstrated that removal of thromboembolic obstruction of the PA was followed by significant improvement of intracardiac haemodynamics, volumetric-and-functional parameters of the right portions of the heart, pulmonary perfusion, accompanied by reverse remodelling of the right heart and lesser circulation (LC), which was manifested by a decrease in the following parameters: systolic and mean blood pressure in the PA, resistance of the LC vessels, total value of perfusion deficiency of the lung, as well as by a decrease in the dimensions of the right chambers of the heart and the diameter of the pulmonary trunk. Normalization of intracardiac haemodynamics resulted in improvement of the clinical and functional state of the patients both in the immediate and remote periods, which was confirmed by elevation of the scores on all scales of the SF-36 Quality of Life Questionnaire, a 2.25-fold increase in the distance walked over a span of 6 minutes, and a decrease in the functional class of chronic heart failure according to the NYHA classification. The obtained findings suggest high efficacy of performing PEA in patients with CTEPH, thus making it possible not only to prolong the lifespan of the patients but to increase their quality of life.

[Exoprosthetic repair of the ascending portion of the aorta: midterm results]. / Ékzoprotezirovanie voskhodiashchego otdela aorty: srednesrochnye rezul'taty.

The authors analyse herein their experience gained in performing the operation of exoprosthetic repair of the ascending portion of the aorta in patients presenting with an ascending aortic aneurysm. This is followed by assessing the results in the remote period. Over the period of follow up from 2012 to 2016 a total of 23 interventions were performed. The average duration of postoperative follow up amounted to 27±9.4 (2-40) months. In the remote period we managed to obtain the data for 20 (90.1%) patients. The patients were interviewed by means of either remote or face-to-face consultations during which we performed assessment of the dimensions of the thoracic portion of the aorta by the findings of MSCT angiography of the aorta. Health-related quality of life was evaluated by means of the Short Form Health Survey Questionnaire SF-36. No statistically significant changes of the aortic sizes were revealed in the remote period as compared with the findings at discharge from hospital. Neither were there repeat interventions related to the operation performed. According to the findings of the SF-36 questionnaire, patients mainly reported improved well-being as compared with that at discharge, including patients having endured coronary artery bypass grafting or prosthetic repair of the aortic valve. Experience shows that using the technique of exoprosthetic repair of the ascending portion of the aorta makes it possible to eliminate dilatation with satisfactory remote results. However, fuller and more reliable assessment of the results requires further studies.

Risk of development of neurological complications in prosthetic repair of the aortic ascending portion and arch. / Risk razvitiia nevrologicheskikh oslozhnenii pri protezirovanii voskhodiashchego otdela i dugi aorty.

The study comprised a total of 68 patients (presenting) with chronic dissection of the aortic ascending portion and arch, undergoing surgery and subjected to measuring at various stages of the operation the level of cerebral oxygenation (rSO2) of the right and left hemispheres by means of bilateral transcranial spectroscopy. The aim of the study was to examine the risk for the development of neurological complications in patients with chronic dissection of the aortic ascending portion and arch in various methods of cerebral protection during aortic prosthetic reconstruction. Group One consisted of thirty-one 40-to-61-year-old (mean age 51 years) patients who during circulatory arrest (CA) were as cerebral protection subjected to antegrade cerebral perfusion (ACP) on the background of moderate hypothermia (23-24°C). Group Two included thirty-seven 40-to-58-year-old (mean age 48 years) patients who during CA were subjected to cerebral protection consisting in craniocerebral hypothermia on the background of total deep hypothermia (18°C). Prior to surgery and in the immediate period thereafter, all patients underwent clinical and instrumental examination of the neurological status. During CA while aortic arch repair in Group One patients at the expense of maintaining cerebral perfusion a decrease in rSO2 registered in the right and left hemispheres amounted to only 11.8 and 8.7%, respectively, compared with the baseline values. In Group Two patients during CA a decrease in rSO2 along the right and left hemispheres amounted to 29.6 and 30.9% compared with the initial values, which was statistically significantly more than in Group One (p=0.002 and p=0.003). Thus, in Group Two patients during CA cerebral hypoperfusion resulted in a considerable decrease in oxygen supply of the brain, in spite of systemic deep hypothermia and craniocerebral hypothermia, promoting reduction of cerebral metabolism. Using ACP during CA in Group One patients maintained the oxygen status of the brain at an optimal level. In Group One patients, in the early postoperative period neurological complications were registered in 12.9% of cases. In Group Two, neurological complications were noted in 35.1% of cases. The univariate logistic regression analysis demonstrated that the risk for the development of any neurological complications depended on the degree of a decrease in rSO2 during CA while prosthetic repair of the aortic arch relative to the previous values - OR 1.25; 95% CI 1.11-1.65; p=0.02. Hence, deep hypothermia and craniocerebral hypothermia used as cerebral protection during CA turned out to be less effective compared with ACP, because despite reduction of metabolic requirements of the brain, cerebral hypoperfusion substantially of neurological status impairments in the early postoperative period.

Hybrid surgery in chronic thoracoabdominal aortic dissection. / Gibridnaia khirurgiia pri khronicheskom rassloenii torakoabdominal'nogo otdela aorty.

The authors describe and analyse their experience gained in performing prosthetic repair of the thoracoabdominal portion of the aorta, combined with open aortic stenting using the Djumbodis uncovered metal stent. Over the period from 2013 to 2015 we performed a total of 16 hybrid interventions. All patients were found to have type B aortic dissection, with their false and true lumens patent. All patients underwent reconstruction of the thoracoabdominal aorta combined with open implantation of the Djumbodis uncovered metal stent into the area of lower thoracic and visceral arteries. The patients underwent either isolated prosthetic repair of the thoracic aortic portion - type A correction, or prosthetic repair of the thoracic and infrarenal portions - type B correction. In the postoperative period we performed MSCT angiography of the thoracic and abdominal aortic portions in order to control patency of the true and false lumens, patency of visceral arteries, to assess the diameter of the aorta, presence or absence of thrombosis. All five patients subjected to type B correction (100% of the total number of this type operation) were found to develop thrombosis of the false lumen, and eight patients undergoing type A correction (72.7% of the total number of operations of this type) were diagnosed with false channel thrombosis. There was 1 (6.3%) lethal case registered at the hospital stage in the group of patients with type A correction. There were no cases of neurological deficit, malperfusion of visceral organs or lower-limb ischaemia. Our experience shows that using hybrid technologies in surgery of the thoracoabdominal portion of the aorta is (appears to be) optimal from the point of view of decreasing intraoperative trauma, reducing the complications rate and without detriment to the radicality.

[Four-year follow up of the results of the first in Russia use of a hybrid prosthesis for surgical management of type I aortic dissection]. / Chetyrekhletnee nabliudenie rezul'tatov pervogo v Rossii primeneniia gibridnogo proteza pri khirurgicheskom lechenii rassloeniia aorty I tipa.

Presented in the articles is a case report of successfully using hybrid prosthesis "E-vita Open plus" (Jotec) in surgical treatment of a female patient presenting with type I chronic aortic dissection according to the DeBakey classification. Careful consideration is given to an uncomplicated course of the early and remote postoperative periods in the first-in-Russia patient to undergo surgery with the use of a new-type prosthesis. The control examinations carried out 6, 12, 28 and 39 months after the operation were unequivocally indicative of complete thrombosis of the false canal of the aorta at the level of the prosthesis and lack of signs of aortic diameter growth below the zone of the surgical intervention. An example of successful treatment of DeBakey type I aortic dissection may be regarded as an important stage in the development of more effective methods of surgery for the severe pathology concerned.

[Open stenting of thoracic aorta in combination with the borst operation].

Described herein in is a clinical case report concerning combined method of surgical treatment for chronic DeBakey type I aortic dissection: prosthetic repair of the ascending aorta and aortic arch according to Borst's technique in combination with open stenting of the descending aorta with the "Djumbodis" uncoated metal stent. This technique makes it possible to achieve expanding of the vascular prosthesis in the descending portion, thus increasing the probability of thrombosis of the false channel at this level and, consequently, to decrease the probability of further dilatation of the thoracic aorta, which is one of the main purposes in aortic reconstruction. Besides, the use of this technique does not exclude a second stage of surgical treatment, both within the framework of the classical surgical technology and with the use of endovascular methods.

[Vacuum-therapy of postoperative sternomediastinitis].

AIM: To estimate the results of sternomediastinitis management using vacuum-therapy compared with conventional treatment of such wounds. MATERIAL AND METHODS: We have retrospectively analyzed data for the period from January 2007 to October 2014. The study enrolled 79 patients with infectious complication after cardiac surgery. All patients underwent coronary artery bypass grafting. The first group included 40 patients who received conventional therapy. The second group enrolled 39 patients in whom vacuum-therapy was applied. Patients were comparable in main characteristics. RESULTS: Mortality rate was significantly lower in vacuum-therapy group (2.5% vs. 15%, p=0.05). Similarly duration of hospital-stay in the 2nd group was 29±10 days, in the 1st group - 47±11 days (p<0.01). Incidence of sepsis and other complications was significantly higher in group of conventional treatment. CONCLUSION: Vacuum-therapy for infectious complications after cardiac surgery provided good results including decrease of hospital-stay duration and mortality rate in comparison with conventional management of wounds.

[Economic Evaluation of Riociguat in Patients with Inoperable or Residual Chronic Thromboembolic Pulmonary Hypertension].

OBJECTIVE: to undertake economic evaluation of riociguat in comparison with standard practice of treating patients with inoperable or residual chronic thromboembolic pulmonary hypertension (CTEPH) in Russian healthcare. METHODS. Standard practice was revealed by means of peer interview. It comprised bosentan monotherapy with addition of sildenafil in case of disease progression. Difference in efficacy between riociguat and bosentan was established through the indirect comparison based on the results of randomized controlled trials. Difference in costs of CTEPH treatment with riociguat and standard practice eas estimated in the Markov model that simulated changes in disease functional class (FC). Direct medical costs were considered and included drugs prescriptions, in-patient and out-patient medical care. Probabilistic sensitivity analysis was conducted. RESULTS: The results of indirect comparison suggest statistically significant higher probability of favorable outcomes in case of treatment with riociguat: improvement by ≥ 1 FC (difference in proportions = 14.8% with 95% confidence interval from 0.1 to 29.5; p = 0.048) and increase of distance in 6-minute walking distance (mean difference = 42.9 m with 95% confidence interval from 10.5 to 75.3; p = 0.009). In base-case scenario difference in costs between riociguat and standard practice was 60,646.15 RUB per 1 patient per year in favor of the former. Riociguat costs were lower in 94.4% of sensitivity analysis cycles. In 72.5% of sensitivity analysis cycles costs difference in favor of riociguat was at least half of that in in base-case. In 47.3% of sensitivity analysis costs difference in favor of riociguat was equal or higher to that in base-case. CONCLUSION: The results of modeling suggest that in Russian healthcare treatment of CTEPH with riociguat is characterized by higher efficacy at lower costs.

Oxygen provision of the brain at various stages of operation in patients with chronic pulmonary artery thromboembolism.

The authors studied cerebral oxygen supply by means of cerebral oximetry in patients presenting with chronic pulmonary artery thromboembolism (PATE) at various stages of operation. The study was aimed at assessing cerebral oxygen supply while carrying out surgical treatment in patients with chronic PATE on the background of various methods of perfusion. Thromboendarterectomy (TEA) from the pulmonary artery with the use of circulatory arrest and craniocerebral hypothermia is accompanied by more pronounced impairment of oxygen supply of the brain with a decrease in the cerebral oxygenation indices by more than 30% from the baseline values. These alterations promote increased risk for the development of neurological complications in the early postoperative period. Using the technique of antegrade cerebral perfusion ensures a minimum decrease of cerebral oxygenation during TEA and contributes to a reduction of the risk for the development of neurological complications.

[Remote results of reimplantation of the aortic valve in patients with ascending aortic aneurysm accompanied by aortic insufficiency].

Valve-sparing operations on the aorta has recently been gaining ever increasing popularity due to more detailed study of physiology of the aortic root, as well as promising mid- and long-term results. The world practice uses various techniques making it possible to remove both ascending aortic aneurysm and aortic valve insufficiency. The authors herein describe and analyse their experience in performing reimplantation of the aortic valve in patients with ascending aortic aneurysm and concomitant aortic insufficiency. Specialists of the clinic of the Novosibirsk Scientific Research Institute for Circulatory Pathology during the period from 2003 to 2013 performed a total of 77 operations of reimplantation of the aortic valve in patients with ascending aortic aneurysm and pronounced aortic valve insufficiency. The majority of patients were men (57 males and 20 females), mean age 53.1±12.2 years (range 21-72). 80% of cases had NYHA functional class II-III circulatory insufficiency (degree 2.3±0.7). Preoperative examination revealed in the majority of patients (97.4%) moderate-to-severe aortic valve insufficiency and ascending aortic aneurysm. All patients underwent reimplantation of the aortic valve. The duration of artificial circulation amounted to 202.4±33 minutes, with the average time of aortic occlusion being 164±28 min. Accompanying procedures (annuloplasty of the mitral valve and/or coronary aortic bypass grafting) were performed in 12 (15.6%) cases. Additional plasty of valvular cusps was carried out in 9 (11.7%) patients, with rethoracotomy required in 5 (6.4%) cases due to haemorrhage. The average period of follow up amounted to 53.3±8.5 (3-115) months. During this time total survival amounted to 91%, with freedom from aortic valve prosthetic repair equalling 93%. The obtained findings suggest that aortic valve reimplantation into the prosthesis is a safe intervention and associated with a comparatively low level of operative lethality. Moderate aortic insufficiency at discharge is a predicting factor for repeat surgical intervention, i.e. prosthetic repair of the aortic valve. No association between the preoperative degree of aortic insufficiency, root diameter and durability of the reimplanted valve was revealed.

[Five-year results of surgical management of patients with chronic post-embolic pulmonary hypertension].

Over the period from 2004 to 2013, a total of 146 patients presenting with chronic post-embolic pulmonary hypertension (CPEPH) underwent the operation of pulmonary thromboendarterectomy (TEE) at the Centre for Surgery of the Aorta, Coronary and Peripheral Arteries. The operation was carried out according to the conventional technique with the use of hypothermia and circulatory arrest. The dynamics of the clinical and functional state was assessed by analysing the following parameters: 6-minute walk test, mean pulmonary artery pressure, and resistance of lesser circulation vessels (according to the data of catheterization of the right parts of the heart), as well as the diameter of the pulmonary artery trunk (by data of MSCT angiography of the pulmonary artery). The distance of the 6-minute walk was indicative of the corresponding functional class of chronic heart failure according to the NYHA classification. The obtained results showed that pulmonary TEE eliminates the main cause of pulmonary hypertension - thrombotic obstruction of pulmonary arteries, thus leading to normalization of the lesser circulation, a decrease in the load on the right ventricle and, consequently, to considerable improvement of the functional state of patients. Performing the operation of TEE from PA branches leads to improved clinical and functional condition of patients with CPEPH both at the hospital stage and further in the remote period after surgery, which is confirmed by a more than 2.5-fold increase of the 6-minute walk distance and a decrease of CHF functional class (by NYHA). A decrease of vascular resistance of the lesser circulation from 539.66±120.59 din×s×cm(-5) before surgery to 101.39±89.20 din×s×cm(-5) in the remote period is indicative of remodelling of the right ventricle and distal arterioles of the lesser circulation. A decrease of the PA trunk diameter from 35.10±5.25 mm before the operation to 30.30±8.65 mm in the remote period is suggestive of structural rearrangement of the pulmonary arterial bed with a tendency towards normalization and of efficacy of surgical treatment performed.