Impact of some intraoperative factors on wound infection in cardiac surgery

Relevanc. Surgical Site Infection (SSI) after open heart surgery is a significant problem in clinical, social, and economic aspect which causes the need to identification of the preferred procedures for successful prevention of the SSI.Objectives. To determine risk of the SSI in cardiac surgery depending on complexity of intervention, using of cardiopulmonary bypass (CBP) and use of both internal mammary arteries (IMA).Methods. Prospective observations study from 2010 to 2019 in cardiac surgery department of the Ural Institute of Cardiology, where in total 4993 open heart surgery procedures were consecutively performed. All SSI cases were recorded up to 90 days after surgery. The analysis was performed to identify risk of cardiopulmonary bypass (CPB), bilateral IMA grafting and combined procedures on the risk of the postoperative wound infection.Results. During the investigation period, total 220 cases of the SSI (4,5%) have been registered of the 4993 patients undergoing open heart surgery. It included 42 cases of deep sternal infection (0,9%) and 178 cases of superficial infection (3,6%). The main pathogen identified was Staphylococcus epidermidis (56,4%). During the hospital period, 151 cases (66,5%) of SSI have been detected, with the median time to detection of the complication 6 days. The relative mortality risk in deep sternal infection group was 4,4 times higher than in the group without SSI (HR 4,6, 95 % CI 1,5-13,9, p=0,003624). CABG increases the relative risk of SSI in compare with non-CABG procedures (OR 3,086169; 95%CI 1,281 – 7,437), while the complexity of the operation (combined versus isolated interventions) does not significantly increase the risk (OR 0.972283; 95% CI: 0.696 - 1.359). The incidence of SSI in the group of in situ BIMA grafting was 8.8%, significantly increasing the likelihood of the SSI in compare to those with SIMA (OR 2.167983, 95% CI 1.463 - 3.212; p =0,000057). CBP significantly increases the risk of postoperative wound infections (OR 1.523890, 95% CI 1.149 - 2.022, p = 0.001742).Conclusions. Refusal of cardiopulmonary bypass, simultaneous procedures and bilateral coronary artery bypass does not allow completely to avoid postoperative wound infections. Nevertheless, the technical features of the preparations and use of grafts, including skeletonization, prevention of coagulation and the preference for sequential composite CABG, can reduce the risk associated with the type of the open heart surgery.

First results of using a bidirectional U-shaped sternal suture in patients who have suffered a deep sternal infection

Introduction. Sternomediastinitis in patients undergoing open heart operation remains a formidable complication. Treatment of a sternal infection is a complex and multi-component process. Closing of the sternal wound is one of the decisive steps in the treatment of sternomediastinitis. This is due to the fact that an insufficiently static state of the sternum in itself leads to a relapse of purulent-septic complications. At the same time, we have to work with non-native bone that has undergone inflammatory and destructive changes and multiple mechanical damage.The objective of the study was to evaluate the results of using the developed bidirectional U-shaped sternal suture for reosteosynthesis of the sternum in patients after postoperative mediastinitis.Methods and materials. The results of treatment of 16 patients with deep sternal infection in the early postoperative period were analyzed. All patients were divided into two groups according to the type of used sternal sutures. The first group consisted of 8 patients in whom a developed bidirectional U-shaped sternal suture was used for sternum reosteosynthesis. In the second group, in 8 patients, the sternal cusps were brought together using classic sternal figure-of-8 suture. A two-stage tactics of treatment was used both in the first and in the second groups of patients. Surgical debridement of the wound with removal of the primary sternal sutures was performed in the first stage. Subsequently, vacuum-assisted therapy was carried out using antiseptics. The second stage was the closure of the sternal wound after cleaning and decontamination of the wound.Results. Signs of sternal suture failure were not observed in the first group. Three patients underwent repeated plasty of the sternum due to the incompetence of the sternal sutures in the second group. One patient had relapse of wound infection.Conclusion. The developed bi-directional U-shaped sternal suture in patients after postoperative sternomediastinitis provides the prevention of inconsistency of sternum.

SURGICAL TREATMENT OF COMPLICATIONS AFTER STERNOTOMY

Summary. The article presents materials of laboratory and instrumental diagnostics of 44 patients with sternal osteomyelitis and comparative treatment with VAC - therapy and open method. Diagnosis was verified by multispiral computed tomography. Ultrasound showed the best results to control the cleaning and healing of sternotomy wounds. The bacterial spectrum showed a predominance of gram-positive microflora in 52.38 % of patients. The use of VAC therapy reduced the duration of hospitalization of patients from (20,3±2,7) to (13,6±5,8) days. Materials and methods. We analyzed the results of treatment of 22 patients who were treated at the State Institution “V.T. Zayceva IGUS NAMSU “in the period from 2014 to 2020 with osteomyelitis of the sternum (OS) after sternotomies. The material for the bacterial study was the isolation of a sternal wound. The antibiotic susceptibility of the isolated bacterial cultures was studied by disco-diffusion method and on agar. Diagnosis of multislice computed tomography (MSCT) was performed using Toshiba Aquilion 64 (Japan). Results and discussion. Wound infection was detected in 42 patients out of 44 examined. A total of 34 strains of microorganisms, representatives of different taxa. S. aureus was dominant and accounted for 23.81 % of the total number of isolates of this genus. In 14.28 % of cases there was contamination of S. epidermidis. E. coli and K. pneumonia 14.28 and 9.52 %, respectively. The most effective in vitro were lincomycin and especially carbopenems (imipenem). Among the instrumental studies we performed fistulography, ultrasound diagnostics (ultrasound) and MSCT. We used VAC therapy in 31 patients and in 13 patients by bandaging depending on the stage of the wound process. The duration was (4.7 ± 1.3) days. There was a decrease in the duration of wound cleansing: with superficial sternal infection — (12.8 ± 5.2) and (4.7 ± 1.3) days; with deep sternal infection — (25.3 ± 1.4) and (10.9 ± 2.2) days; term of hospitalization of patients with superficial sternal infection — (27.3 ± 5.6) and (13.6 ± 5.8) days; term of hospitalization of patients with deep sternal infection — (41.2 ± 3.5) and (20.3 ± 2.7) days. Conclusions. 1. In the diagnosis of OS should be preferred MSCT, which allows to verify the diagnosis in up to 99 % of cases, and the use of ultrasound to monitor the cleaning and healing of sternotomy wounds. The use of VAC therapy reduced the duration of hospitalization of patients from (20,3±2,7) to (13,6±5,8) days.

Longitudinal-cross-linking method of the sternum osteosynthesis – an additional way for the prophylaxis of deep sternal infection in cardiac surgery patients

The OBJECTIVE of the study was to compare the results of using the longitudinal – cross-linking method of sternum osteosynthesis with other methods (single wire stitches, 8-shaped wire stitches) for cardiosurgery patients.METHODS AND MATERIALS. The study included 3,150 patients, which were operated on in Samara cardiology dispensary named after V. P. Poliakov from 2012 to 2018. Patients were divided into 2 groups. Group 1 (1397 patients, operated on from 2012 to 2014) used single wire stitches or 8-shaped wire stitches for sternum osteosynthesis. Group 2 (1753 patients, operated from 2015 to 2018) used the longitudinal -cross-linking method of sternum osteosynthesis. The incidence of instability of the sternum without infection, superficial postoperative wound infection, deep sternal infection and hospital mortality were evaluated.RESULTS. Groups (1–68 % of men, average age (59.4±9,9) years; 2–68 % of men, average age 62.3±8.5) were significantly different in obesity patients (25.6 & 29.3 %, p=0.02), amount of smokers (50.5 & 64.2 %, p<0.001) and amount of urgent cases (3 & 10 %, p<0.001). The incidence of sternal instability without infection was less in group 2 (0.64 & 0.29 %; OR, 2.29; 95 % CI, 0.76 to 6.8; p=0.1). The amount of deep sternal infection was significant less in group 2 (1.6 & 0.6 %; OR, 2.53; 95 % CI, 1.2 to 5.2; p=0.009). The hospital mortality was 3.9 % in group 1 and 2.96 % in group 2 (OR, 1.34; 95 % CI, 0.9 to 1.9; p=0.1).CONCLUSION. The longitudinal-cross-linking method of sternum osteosynthesis is the available method that can significantly reduce the incidence of deep sternal infection in cardiosurgery.

RISK FACTORS FOR WOUND INFECTION DEVELOPMENT IN PATIENTS AFTER MEDIAN STERNOTOMY

More than 53,000 open heart and thoracic aortic surgeries are performed annually in the Russian Federation. The main access for these operations is the median sternotomy. The aim of the study was to assess risk factors and their influence on wound infection development in patients after median sternotomy. Materials and Methods. Fifty-eight patients were enrolled in a retrospective, and prospective study. All patients were divided into two groups comparable by sex and age. Group 1 included 28 patients with sternal infection in the early postoperative period, Group 2 consisted of 30 patients without purulent-inflammatory complications of a sternal wound. Results. Diabetes mellitus, obesity, generalized atherosclerosis and their combination are more common in patients with purulent-inflammatory wound complications in comparison with patients of Group 2. The abovementioned diseases are respectively 3.2; 2.9; 2.4; 5.4 times as frequent as in Group 2 (p<0.05). The duration of cardiopulmonary bypass, aortic occlusion, and surgery duration in patients with postoperative wound infection was significantly longer than in patients without sternal infection (p<0.05). Conclusion. Diabetes mellitus, obesity, generalized atherosclerosis and their combination are observed significantly more often in patients with wound infection. A longer time for surgery, cardiopulmonary bypass and aortic occlusion contributes to wound infection development in patients after median sternotomy. Keywords: risk factors, median sternotomy, wound infection, open heart surgery. Ежегодно в Российской Федерации выполняется более 53 000 операций на открытом сердце и грудном отделе аорты. Основным доступом при данных операциях является срединная стернотомия. Цель исследования – оценка влияния факторов риска на развитие раневой инфекции у пациентов после срединной стернотомии. Материалы и методы. Исследование ретроспективное, проспективное. 58 больных были распределены на две сопоставимые по полу и возрасту группы. В первую вошли 28 пациентов с наличием стернальной инфекции в раннем послеоперационном периоде, во вторую – 30 пациентов без гнойно-воспалительных осложнений стернальной раны. Результаты. Сахарный диабет, ожирение, генерализованный атеросклероз и их сочетание у пациентов с гнойно-воспалительными раневыми осложнениями по сравнению с больными второй группы встречаются чаще в 3,2; 2,9; 2,4; 5,4 раза соответственно (p<0,05). Продолжительность проведения искусственного кровообращения, окклюзии аорты и длительность выполнения операции у пациентов с послеоперационной раневой инфекцией были достоверно больше, чем у пациентов без признаков стернальной инфекции (p<0,05). Выводы. Сахарный диабет, ожирение, генерализованный атеросклероз и их сочетание у больных с раневой инфекцией наблюдаются достоверно чаще. Более длительное время проведения операции, искусственного кровообращения и окклюзии аорты способствует возникновению раневой инфекции у пациентов после срединной стернотомии. Ключевые слова: факторы риска, срединная стернотомия, раневая инфекция, операции на открытом сердце.

Анализ развития стернальной инфекции у кардиохирургических больных

A clinical study including 68 patients of a cardiac profile who developed sternal infection in the postoperative period was conducted. Patients were divided into two groups: 1 group – 42 patients with a sternal infection of soft tissues and the 2nd group – the 26th patient with a sternal infection of a breast. The received results were processed statistically. The received data confirmed that patients of both groups had an accompanying pathology: diabetes mellitus and chronic obstructive diseases of lungs. The risk factor for infection development during sternotomy were an average duration of operation that in the 1st group was 280,9 minutes and in the 2nd group the operation duration was 270,4 minutes. Another risk factor was duration of use of the device of artificial blood-flow; cardiac support was used for 24nd group. A prolonged artificial pulmonary ventilation was used in 39 (92,9 %) patients of the 1st group and 22 (84,6 %) patients of the 2nd group.

Unilateral Pedicled Pectoralis Major Harvested by Endoscopic-Assisted Method Achieves Adequate Management of Sternal Infection and Mediastinitis

Background Bilateral PM muscles or combination with rectus abdominis or omentum are commonly used for upper and lower sternal wound infections. Unilateral PM harvesting using endoscopic-assisted method may have a simple, safe, and reliable entire muscle harvesting with comparable result of less donor-site violation. Methods A retrospective review was performed from 2003 till 2015 on 38 patients referred to a single plastic surgeon for treatment of sternal wound infection following median sternotomy for cardiovascular surgery. After the humerus insertion of PM was cut with the assistance of endoscope visualization, all the other PM insertions on the sternum, rib, and clavicle were divided, the unilateral pedicled PM can be advanced approximately 10 cm to cover the cephalad and caudal sternum, and fill the retrosternal mediastinum. Results Four re-explorations in three patients for postoperative hematoma occurred. No early recurrent infection for wound dehiscence experienced. Three patients died of multiple organs failures as 30-day mortality. Two patients underwent late recurrent infections; one patient had twice wire infection removals at 4 and 6 months after transfer, and the other had another PM for rib osteomyelitis in 3 years. Conclusion Unilateral PM transfer is justified to provide a simple, reliable, straightforward procedure for sternal infection management and mediastinal obliteration without violation of second flap in compromised patients.

Are two internal thoracic grafts better than one? An analysis of 5301 cases

OBJECTIVES Although bilateral internal thoracic artery (BITA) grafting is associated with improved survival, many surgeons are reluctant to use this technique due to its greater complexity and the potentially increased risk of sternal infection. This observational study examined if BITA grafting provides improved outcomes compared with single internal thoracic artery (SITA) grafting in patients with multivessel coronary disease. METHODS Patients in our institution who underwent BITA grafting during 1996–2011 were compared to those who underwent SITA grafting during the same period. To adjust for differences in demographic and clinical characteristics, patients were matched by propensity score. The Cox model was used to identify predictors of decreased survival and the Kaplan–Meier analysis was performed, both for the entire cohort and for the matched cohort. RESULTS SITA patients were older than BITA patients, included more females, and were more likely to have chronic obstructive lung disease, an ejection fraction <30%, diabetes, renal insufficiency, peripheral vascular disease and emergency and repeat operations. Three-vessel and left main diseases were more common among BITA patients, and operative mortality was reduced (2.1% vs 3.6% for SITA, P = 0.002). Sternal infection and stroke rates were similar for the groups. Ten-year Kaplan–Meier survival of BITA patients was better (71.2% vs 56.8%, respectively, P < 0.001). BITA grafting was found to be a predictor of better survival in the analysis of the matched cohort (P < 0.001). CONCLUSIONS Our results support the routine use of BITA grafting in patients who undergo myocardial revascularization.