Open transaortic implantation of 'Medlab-KT' prosthesis. / Otkrytaia transaortal'naia implantatsiia proteza 'Medlab-KT'.

AIM: The study was aimed at comparing the immediate clinical and haemodynamic results of open implantation of the balloon-expandable aortic prosthesis 'MedLab-KT' with the respective parameters of standard replacement of the aortic valve by a mechanical prosthesis in high-risk surgical patients. PATIENTS AND METHODS: We analysed a total of 209 cases of prosthetic repair of the aortic valve. The Study Group comprised 28 patients subjected to open implantation of the 'MedLab-KT' prosthesis in conditions of extracorporeal circulation and myocardial ischaemia and belonging to a high-surgical risk cohort. The Comparison Group included 181 patients who endured standard open prosthetic repair of the aortic valve with a mechanical prosthesis. Using the ppropensity score matching method, we selected 28 patients from the Comparison Group, followed by assessing the incidence of adverse clinical events and haemodynamic parameters of the aortic valve prosthesis at the in-hospital stage. RESULTS: There were no lethal outcomes in the study group, with one in the group of standard aortic valve repair - 3.6%. The mean operative time in the Study and Comparison Group patients amounted to 121.5±51.2 and 274.2±55.3 min (p=0.04), the duration of extracorporeal circulation to 56.1±19.5 and 119.9±23.4 min (p=0.04), that of myocardial ischaemia to 38.4±17.1 and 96.7±20.8 (p=0.03), respectively. The mean gradient on the aortic valve in the 'MedLab-KT' group was less (7.5±3.2 mm Hg) than in those of the second group (9±3.5 mm Hg), with no statistically significant differences in the parameters revealed (p=0.096). All patients of the study group were discharged from hospital in a satisfactory condition, with the haemodynamic result of the operation regarded as satisfactory. CONCLUSION: Comparing the main clinical characteristics and haemodynamic parameters in the groups of 'MedLab-KT' and aortic valve prosthetic repair at the hospital stage revealed no statistically significant differences. Open implantation of the 'MedLab-KT' prosthesis proved safe and effective.

Role of flowmetry in tactics of bypass grafting for myocardial bridge of the anterior descending artery. / Rol' floumetrii v taktike shuntirovaniia miokardial'nogo mosta perednei niskhodiashchei arterii.

The purpose of the study was to analyse the remote results of bypass grafting for myocardial bridges. Our retrospective single-centre study included a total of 17 patients subjected to coronary bypass grafting of the anterior descending artery (ADA) in connection with a detected myocardial bridge (MB). All patients underwent assessment of the coronary bypass grafts (CBG) by means of intraoperative flowmetry - transit time flow measurement (TTFM), as well as angiographic control of the CBGs in the remote period. The duration of follow up amounted to 72 months. Six patients were found to have pronounced retrograde blood flow accompanied by an elevated index of peripheral resistance (Pi) and decreased mean volumetric blood flow velocity (Qmean) below the threshold values. Compression of the ADA proximal to the anastomosis appeared to be followed by improvement of blood flow parameters, in connection with which the shunted artery was ligated with monofilament polypropylene suture 4/0. According to the findings of coronary bypass angiography (CBA) the following results were obtained: 4 occluded grafts were revealed in the group of patients in whom ligation of the ADA was not performed. In patients subjected to ADA ligation in connection with pronounced retrograde blood flow, all bypass grafts were competent. The cumulative probability of freedom from graft occlusion was significantly higher in the group of patients subjected ADA ligation proximal to the anastomosis (Log Rank=0.032).

[Risk factors for progression of atherosclerosis of the shunted coronary artery in the remote postoperative period]. / Faktory riska progressirovaniia ateroskleroza shuntiruemoi koronarnoi arterii v otdalennom periode.

The study was aimed at revealing risk factors for progression of atherosclerosis in the shunted coronary artery in the remote period following coronary artery bypass grafting. Our prospective study included a total of 292 patients having endured coronary artery bypass grafting. All patients were divided in two groups depending on the type of the bypass grafts used: either autoarterial shunts (Group 1) or autovenous grafts (Group 2). We thus assessed a total of 516 autoarterial grafts and 257 autovenous grafts, as well as the coronary arteries shunted thereby. The long-term results were evaluated by means of coronaroshuntography performed not earlier than 12 months after surgery. The average duration of follow up amounted to 53.4±26.5 months. Analysing the cumulative risk for progression of atherosclerosis in the arteries shunted demonstrated that for autoarterial grafts the rate of the development of proximal stenosis of the coronary artery (CA) shunted was lower compared with autovenous grafts (p≤0.001). The Cox regression model showed that an autovein used as a graft increased the risk for the development of occlusion of the shunted CA by 43% from the baseline each postoperative month. The presence of proximal stenosis of the shunted coronary artery amounting to or exceeding 90% increases the risk of occlusion by 68% per month. Also, for the patients with the SYNTAX scoring ≥ 32 points the risk of coronary artery occlusion increases 2.2-fold each month after the operation. Such factors as the patient's gender, the diameter of the shunted artery, diabetes mellitus, tobacco smoking, multifocal atherosclerosis by the findings of the study exerted no influence on the progression of proximal stenosis of the shunted coronary artery.

[Indices of intraoperative flowmetry, determining patency of grafts in the remote period after revascularization of the right coronary artery].

The authors studied the threshold values of ultrasound flowmetry concerning composite T-grafts, combined I-grafts, and autovenous shunts during revascularization of the right coronary artery (RCA), determining high risk for the development of shunt occlusion in the remote postoperative period. The retrospective study included a total of 223 patients subjected to revascularization of the RCA's basin with the help of composite T-grafts, combined I-grafts, and autovenous shunts. Depending on the method of bypass grafting of the RCA and its branches, all patients were subdivided into 3 groups: Group 1 was composed of 65 patients in whom the RCA basin was revascularized by a branch of the composite T-graft, Group 2 comprised 112 patients who endured autovenous aortocoronary bypass grafting, and Group 3 consisted of 46 patients in whom the RCA basin was shunted by a combined mammarovenous I-graft. The groups had no statistically significant differences on the main clinical and demographic parameters. Intraoperative assessment of the blood flow through the coronary shunts was carried out by means of ultrasound flowmetry. The remote results were evaluated based on the findings of the control coronaroshuntography which was carried out in all patients within the terms varying from 16 to 43 months. In the remote period in Group 1 patients (T-graft), 59 (90%) mammary shunts were patent, in Group 2 - 99 (88.4%) autovenous shunts, and in Group 3 (I-graft) 42 (95.5%) shunt were patent. Cumulative probability of freedom from shunt occlusion within the terms up to 3 years after surgery in Group 1 amounted to 82±0.5%, in Group 2 to 58±2.1%, and in Group 3 to 86±1.9%, with the differences between Group 2 and other groups being statistically significant (p=0.01). The Poisson regression analysis showed that the risk for graft occlusion increased by 10% with the resistance index in the branch of the T-graft from 4.0; by 8% with the resistance index in the autovein from 2.9; and by 3% with the index of resistance in the I-graft from 3.2. The conclusion was made that composite T-grafts and combined I-grafts demonstrated similar results of patency within the terms up to 3 years, possessing advantages over autovenous conduits while shunting the RCA basin. The optimal index of peripheral resistance for the autovein during revascularization of the RCA basin is up to 2.9; for the combined T-graft - up to 3.2, and for the composite T-graft - up to 4.0. Probability of shunt occlusion in the remote period does not depend upon the average volumetric blood velocity (Qmean) but is directly proportional to the value of the pulsatility index (Pi) which reflects the state of the distal bed.

[Flowmetric assessment of coronary bypass grafts in the conditions of artificial circulation and on the beating heart].

Advantages and shortcomings of aortocoronary bypass grafting on the beating heart and in the conditions of artificial circulation (AC) have long been discussed. The data on patency of bypass grafts in the remote period are indicative of comparable results of operations with and without AC or advantages of using AC. In order to determine benefits of each method it is necessary to reveal intraoperative predictors of bypass grafts occlusion in the remote period. We analyzed the results of ultrasound flowmetry of the blood flow through the left internal thoracic artery during bypass grafting of the anterior descending artery with the use of AC and on the beating heart. A retrospective study included a total of 352 patients subdivided into 2 groups: Group One was composed of 120 patients undergoing surgery in the conditions of AC and Group Two comprised 232 patients subjected to similar operations on the beating heart. Blood flow was measured with the help of flowmeter VeryQ MediStim® after termination of AC and inactivation of heparin by protamine, with systolic pressure of 100-110 mm Hg. There were no statistically significant differences between the groups by the diameter and degree of stenosis of the anterior descending artery, diameter of the left internal thoracic artery. The mean volumetric blood flow velocity (Qmean) along the shunts in Group One was higher (p=0.01). No statistically significant differences by the pulsatility index (PI) between the groups were revealed (p=0.2). A conclusion was drawn that coronary bypass grafting of the anterior descending artery by the left internal thoracic artery in the conditions of artificial circulation made it possible to achieve higher volumetric velocity of blood flow through the conduit as compared with operations on the beating heart, with similar resistance index. The immediate results of the operations with the use of the both techniques did not differ.

[Prevention of wound infection in cardiac surgery: how much is topical use of antibiotics justified?].

The authors studied efficacy of preventing wound infection of a sternotomic wound with and without conventional use of topical antibiotics, also determining predictors of the development of infectious complications after cardiosurgical interventions. Our retrospective study included a total of 1,593 patients subdivided into two groups. In Group One patients (n=951) sternal infection was prevented according to the P. Vogt technique; Group two patients (n=642) were also subjected to the same methodology, but with the exception of topical use of antibiotics. By the frequency of re-sternotomies performed, cases of superficial and deep wound infection, as well as by the average duration of operation, hospital and ICU stay there were no statistically significant differences between the groups (p<0.05). The average cost of antibacterial agents as calculated per one patient in Group One turned out substantially higher than in Group Two (amounting to 8.1±3.9 and 3.3±1.4 thousand roubles, respectively, p<0.001). Analysing possible predictors of the risk for the development of wound infection showed that the body mass index, duration of the operation, and performing re-sternotomy exerted a statistically significant influence on probability of infections complications. It was determined that using the methodology of preventing sternal infection with topical application of antibiotics led to predominance of Gram-negative flora in the wound discharge (p=0.02). Exclusion of topical use of antibiotics does not lead to an increase in the incidence rate of wound complications (p=0.78) and normalizes the ratio of Gram-negative and Gram-positive strains.

[Aorta-associated complications after prosthetic repair of the aortic valve].

The authors analyzed dependence between the presence of preoperative predictors of aorta-associated complications and risk for the development of these complications in the remote period after prosthetic repair of the aortic valve. The study included a total of 231 patients subjected to aortic valve prosthetic repair with no additional intervention on the root and ascending portion of the aorta. The follow up duration varied from 12 to 62 months. As predictors of the development of aorta-associated complications we examined such factors as the bicuspid structure of the aortic valve, dilatation of the aortic ascending portion relative to the upper border of the individually calculated norm, disordered configuration of the complex "aortic root - ascending portion of the aorta", resistant arterial hypertension, diabetes mellitus. Depending on the number of predictors for the development of aorta-associated complications the patients were subdivided into 2 groups: Group One consisting of 105 patients with two and more predictors of the development of aorta-associated complications, and Group Two comprising 126 patients with not more than one predictor of the development of aorta-associated complications. It was determined that in the first group of patients the total number of aorta-associated complications in the remote period after prosthetic repair of the aortic valve amounted to 25.7% (27 of 105 patients). The total number of aorta-associated complications in the second group amounted to 1.6% (2 of 126 patients). All detected aorta-associated complications were divided into "critical" and "noncritical". The critical complications were those the detection of which required performing a second operation in the patient: formation of an ascending aortic aneurysm and type A aortic dissection. To the "noncritical" aorta-associated complications belonged dilatation of the ascending portion of the aorta progressing at a rate of 2 mm/year. Resulting from the performed study it was determined that each specific of the examined predictors exerted no influence on the risk for the development of aorta-associated complications in the remote period after prosthetic repair of the aortic valve (p>0.05). Any combination of two and more predictors in one patient considerably increased the risk for the development of complications (p<0.001). A conclusion was made that revealing two and more predictors of the development of aorta-associated complications in one patient it is appropriate to perform a simultaneous operation of prosthetic repair of the aortic valve and the ascending aortic portion.