[Effect of the degree of stenosis of the right coronary artery on remote results of bypass grafting]. / Vliianie stepeni stenoza pravoi koronarnoi arterii na otdalennye rezul'taty shuntirovaniia.

AIM: The purpose of this study was to assess the long-term results of right coronary artery bypass grafting and identify predictors of coronary artery bypass graft occlusion. PATIENTS AND METHODS: Our retrospective single-centre study included a total of 245 patients subjected to isolated coronary artery bypass graft operations during the follow up period from 2010 to 2015. All patients endured bypass grafting of the right coronary artery (RCA) with either autovenous or autoarterial conduits. Control coronary bypass angiography was performed in all patients in connection with a relapse of angina pectoris. The duration of the follow up period amounted to 43.7±20.2 months. The patients were divided into two groups depending on the type of the conduit used to bypass the RCA. Group One patients (n=106) endured bypass grafting of the RCA and its branches using the internal thoracic artery. Group Two patients (n=139) underwent autovenous coronary artery bypass grafting of the RCA basin. By the main clinical, demographic and intraoperative parameters the groups were statistically homogeneous (p>0.05). The effect of the degree of proximal stenosis, the diameter of the grafted artery on the viability of bypass grafts was assessed. RESULTS: During the follow-up period up to 84 months, 19 (17.9%) occluded arterial and 29 (20.9%) venous conduits were revealed. The Kaplan-Meier analysis showed that the probability of the absence of venous graft occlusion during the follow-up period up to 84 months was significantly lower than that of arterial grafts (log rank=0.012). The Cox regression analysis results revealed that shunt occlusion was influenced by the degree of proximal stenosis and the diameter of the shunted artery. CONCLUSION: When shunting a moderate stenosis of the RCA (up to 70%), an advantage of autovenous conduits was revealed. When shunting the RCA with a critical stenosis and occlusion, advantages were revealed for the internal thoracic artery.

Results of flowmetric assessment of composite Y-grafts and autovenous coronary artery bypass grafts. / Rezul'taty floumetricheskoi otsenki kombinirovannykh I-graftov i autovenoznykh aortokoronarnykh shuntov.

AIM: The purpose of the study was to perform intraoperative assessment of blood flow in coronary bypass grafts of the 'first' and 'third' order according to Calafiore A.M. with the help of the TTFM technique and to compare the obtained results. PATIENTS AND METHODS: This retrospective, single-centre study enrolled a total of 222 patients subjected to coronary artery bypass grafting (CABG) from January to November 2017. Depending on the type of bypass grafting of the posterior interventricular artery (PIVA), the patients were divided into 2 groups. Group One consisted of 108 patients undergoing bypass grafting of the PIVA with the help of combined Y-grafts from the right internal thoracic artery (RTIA). Group Two was composed of 114 patients subjected to autovenous coronary artery bypass grafting of the PIVA. Blood flow was assessed with the help of the VeriQ MediStim® flowmeter after termination of extracorporeal circulation (ECC), at systolic pressure of 100-110 mm Hg. The parameters of blood flow were assessed using the 1.5- and 2-mm probes. In a specially designed protocol we registered the type of the shunt, the bypassed artery, and values of flowmetry parameters. We also evaluated the pattern of the flowmetric curve according to Takemi Handa et al. RESULTS: The obtained findings revealed a statistically significant difference in the values of Qmean (p=0.001), with the PI values in the groups not statistically differing (p=0.14). Thus, in patients with similar parameters influencing the volumetric velocity of blood flow (the degree of proximal stenosis, diameter of the bypassed artery, mean systolic AP and HR) the value of Qmean was higher in the group with coronary artery bypass grafting (CABG), i. e., in the group of the 'first-order' conduits. Therefore, an autovein directly anastomosed to the aorta experiences grater haemodynamic overload, which completely confirms the theory of Calafiore A.M. CONCLUSION: First-order conduits (CABG) appear to experience greater wall strain because of greater haemodynamic overload as compared with third-order conduits (Y-grafts). A composite Y-graft may be an alternative technique of bypass grafting of the basin of the right coronary artery (RCA). A composite Y-graft has greater resistance to wall shear stress than an autovein anastomosed to the aorta.

[Predictors of early occlusion of coronary bypass grafts in patients with extremely low ejection fraction]. / Prediktory rannei okkliuzii koronarnykh shuntov u patsientov s kraine nizkoi fraktsiei vybrosa.

The authors carried out a retrospective study aimed at revealing predictors of early incompetence of coronary bypass grafts in patients with the ejection fraction below 30%. The study included a total of 104 patients presenting with coronary artery disease and the ejection fraction below 30%, who over the period from 2009 to 2016 underwent coronary artery bypass grafting with the use of autovenous and autoarterial conduits. 77 patients endured plasty of an aneurysm of the left ventricle (LV), 89 patients sustained plasty of the valvular apparatus. All patients were subjected to control coronary bypass angiography (CBA) within 12 postoperative months. Thus, we analysed a total of 184 autoarterial and 84 autovenous shunts. The findings of CBA revealed occlusions of 2 (1%) arterial and 10 (11%) venous conduits. Analysing the coronary bypass angiographies of the patients ranked according to the values of the effective stroke volume index demonstrated the following regularity: a decrease in the LV effective stroke volume index of less than 30 ml/m2 was accompanied bу increased incidence of thrombosis of autovenous shunts in the immediate postoperative period. Predictors of early occlusion of coronary bypass grafts were revealed by means of the Cox regression analysis. It was determined that using an autovein increased the risk of occlusion of the shunt by 26%, a decrease in the effective stroke volume index of the left ventricle by 1 ml/m2 increased the risk of early occlusion of coronary bypass grafts by 18%, a decrease in the diameter of the shunted artery by 0.5 mm increased the risk for early occlusion of the shunt by 12%, a decrease in the blood flow velocity (Qmean) by 1 ml/m2 increased the risk for occlusion of the shunt by 10%, a decrease in the peripheral resistance index (RI) by 1 unit elevated the risk of early occlusion of the bypass graft by 12%. Analysing the revealed independent predictors with the help of the neural network method demonstrated that the strongest influence on early incompetence of the coronary bypass graft was exerted by the type of the conduit and effective stroke index.

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).

[Flowmetric and angiographic predictors of occlusion of coronary bypass grafts]. / Floumetricheskie i angiograficheskie prediktory okkliuzii koronarnykh shuntov.

OBJECTIVE: The study was aimed at assessing remote (up to 42 months) results of coronary artery bypass grafting (CABG) and revealing flowmetric and angiographic predictors of coronary bypass graft occlusion. PATIENTS AND METHODS: Our retrospective single-centre study included a total of 141 patients undergoing coronary artery bypass grafting (CABG). All patients were subjected to assessment of coronary bypass grafts by means of transit-time flowmetry (TTFM), as well as angiographic control of coronary bypass grafts in the remote period. The duration of follow up amounted to 42 months. We performed flowmetric assessment of blood flow by the following parameters: mean volumetric blood flow velocity (Qmean), peripheral resistance (PR), as well as studied angiographic parameters such as: the degree of proximal stenosis of the bypassed coronary artery (CA), the diameter of the bypassed CA. Competence of bypass grafts after carried out coronaroshuntography (CSG) was determined according to the classification of Fitzgibbon. RESULTS: We performed flowmetric and angiographic assessment of 235 autoarterial and 117 autovenous bypass grafts. During the follow-up period of up to 42 months we revealed 33 (14%) occluded arterial conduits and 30 (25.6%) venous ones. The Kaplan-Meier analysis demonstrated that the probability of the lack of occlusions of venous grafts amounted to 74.4±5.8%, with that of arterial grafts equalling 86±3.3%, i. e. during the follow-up period of up to 42 months, the probability of occlusion of venous grafts was reliably higher than that of arterial ones (Log Rank=0.006). The Cox regression analysis made it possible to reveal that occlusion of grafts was influenced by an increase in the peripheral resistance index (p=0.033, HR=1.374), a decrease of volumetric blood flow velocity in the graft (Qmean) (p=0.005; HR=0.981), and by the type of the graft (venous) (p=0.001; HR=2.587). CONCLUSIONS: 1) arterial grafts appeared to yield better results of myocardial revascularisation within the terms up to 42 months as compared with venous coronary artery bypass grafting; 2) using a vein increases the risk for the development of graft occlusion 2.5-fold each month after the operation; 3) an increase in the peripheral resistance index (PR) by 1 unit elevates the risk of occlusion of the coronary graft 1.3-fold with each month after the operation; 4) a decrease in the volumetric blood flow velocity (Q) by 1 ml leads to an increase in the risk of graft occlusion by 2% with each month after the operation.

Preoperative and intraoperative assessment of volumetric blood flow velocity through the internal thoracic artery in patients with cad. / Predoperatsionnaia i intraoperatsionnaia otsenka ob''emnoi skorosti krovotoka po vnutrennei grudnoi arterii u bol'nykh IBS.

The left internal thoracic artery (ITA) is currently an artery of choice for revascularization of coronary arteries. Ultrasonographic duplex scanning (USDS) and ultrasound Doppler flowmetry (UDF) are sequential techniques to control patency of the ITA at stages of rendering care for patients on restoring coronary blood flow. We compared two methods of measuring the volumetric blood flow velocity: by means of USDS and UDF. The obtained results were statistically processed. It was determined that transthoracic USDS and intraoperative UDF in the assessment of the volumetric blood velocity through the ITA in patients with coronary artery disease are comparable methods, provided the patients have similar parameters of central haemodynamics.

[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.

[Comparative analysis of the results of using the method of elimination of sternal infection and standard methodology of cardiosurgical operations].

Postoperative mediastinitis belongs to one of the severest complications of cardiosurgical operations. There have been suggested many methods of pre- and intraoperative prevention of sternal infection. Summarizing the obtained experience, in 2006 specialists of the EurAsia Heart Foundation under the leadership of Professor P. Vogt (Im Park Clinic, Zurich, Switzerland) elaborated and suggested a methodology of eliminating sternal infection, which according to the author s opinion made it possible to decrease the frequency of the development of sternal infection from 5.6 to 0%. This methodology was implemented at the Federal Centre of Cardiovascular Surgery (city of Penza) in July 2012, thus leading to a decrease in the rate of wound complications from 4.05 to 0.3%.

[Ultrasonic doppler flowmetry in intraoperative diagnosis of coronary bypass grafts incompetence].

According to the findings of many authors, occlusion of bypass grafts may develop as early as during surgery in 4-12% of patients. At discharge from hospital this index may reach 5-20%, increasing to 30% within the first year. Incompetence of bypass grafts is in many cases a consequence of errors in surgical technique and may therefore be decreased by means of improving the control over quality of coronary bypass grafting. Using the method of ultrasound Doppler flowmetry in the conditions of artificial circulation and clamped artery, we assessed a total of 64 composite bypass grafts. Blood flow was assessed by such parameters as the pulsatility index (PI), mean volumetric blood flow velocity (Qmean), and percentage of diastolic volumetric filling (DF). The obtained results were statistically processed. The mean values of blood flow parameters were obtained, followed by determining dependence between peripheral resistance (PI) prior to removal of the clamp from the aorta and peripheral resistance (PI) measured after termination of extracorporeal circulation.

[Intraoperative assessment of composite bypass grafts by means of ultrasonic Doppler flowmetry].

The use of the both internal thoracic arteries while forming a composite bypass graft has been suggested as a method making it possible to carry out total myocardial revascularization. However, controversial still remain the problem of the distribution of blood in these bypass grafts, as well as that concerning T-grafts' capability of providing the sufficient blood inflow to the basin of the coronary arteries being bypassed. The method of ultrasonic Doppler flowmetry was used to perform the intraoperative assessment of 59 composite bypass grafts along such parameters as the pulsatility index (PI), mean volume blood flow velocity (Qmean), and percentage of diastolic volumetric filling (DF). The obtained findings were statistically processed making it possible to obtain the average parameters of blood flow for the composite bypass grafts and their branches. A dependence was established between blood flow distribution in the composite conduit and the degree of the lesion of the artery being bypassed.