Bilateral internal thoracic artery use in two-vessel disease does not increase the perioperative risk—A propensity score matched analysis

Background Bilateral internal thoracic arteries (BITA) are uncommonly used in the every-day practice due to safety concerns and technical challenges with Y-grafts. We hypothesized that in-situ BITA use during coronary artery by-pass grafting (CABG) for two vessel disease is equally safe to standard strategy with left internal thoracic artery-left anterior descending artery revascularization and venous graft to other target vessels. Methods A propensity score matched analysis was used to compare elective on-pump CABG patients who received in-situ BITA (BITA-group), versus left internal thoracic artery graft to the left anterior descending artery plus vein (SITA-group). Primary end points were 30-days all-cause-mortality, major adverse cardiac events and incidents and deep sternal wound infections. Results A total of 50 matched pairs (c-statistics 0.769) were selected from patients operated on between January 2015 and April 2020 using BITA (n = 50) and SITA (n = 2170). There were no inter-group differences in demographics and basic clinical characteristics. The total operation time was longer in the BITA-group (4.0 vs 3.6 hours; p = 0.004). The rate of complete revascularization was similar, as was median aortic cross-clamp time, median extracorporeal circulation time, rate of re-explorations for bleeding, deep sternal wound infections or length of stay. One patient died in BITA group, 3 days after surgery, from a non-cardiac cause. After 36 months, the survival rate was 98% for BITA-group and 96% for controls (log-rank, p = 0.577). Conclusions In-situ use of BITA during coronary revascularization for two-vessel disease is as safe and effective, as use of single ITA and vein graft. In-situ strategy abolishes allows to avoid the technically demanding composite graft configuration.

Treatment of Cardiac Surgical Wounds with Silver Dressings

Introduction. Mediastinitis is a deadly surgical site infection (SSI) after cardiac surgery. Although rare, mortality is as high as 47%. Best practices for infection prevention to eliminate this deadly complication must be identified. Surgical dressings impregnated with silver have been shown to reduce SSIs in other surgical specialties. This aim of this study is to determine if the routine use of silver surgical dressings is beneficial to prevent mediastinitis after cardiac surgery. Methods. A single-center retrospective study was performed on patients who underwent sternotomy from 2016 to 2018 at the University of Kansas Medical Center. Prior to June 2017, all cardiac surgical patients were treated with gauze surgical dressings and is designated Group A. The routine use of silver-impregnated surgical dressings was implemented in June 2017, patients after this change in practice are designated Group B. Patient characteristics and rates of deep and superficial sternal wound infections (SWI) were compared. Results. There were 464 patients in Group A and 505 in Group B. There were seven SWIs in Group A (7/464, 1.5%) and five in Group B (5/505, 1%; p = 0.57). Of these, there was one deep SWI per group (p = 0.61) and six superficial SWIs in Group A compared to four in Group B (p = 0.74). Severe COPD was higher in Group A (p = 0.04) and peak glucose was higher in Group B (p = 0.02). Conclusions.The analysis conferred no benefit with silver-impregnated surgical dressings to prevent mediastinitis. Choice of gauze surgical dressings may be preferable to reduce cost.

Antimicrobial stewardship measures in cardiac surgery and its impact on surgical site infections

Objective The goal of this study was to monitor the compliance and impact on a protocol change of surgical antimicrobial prophylaxis in cardiac surgery favouring cefazolin instead cefuroxime, initiated by the hospital’s antimicrobial stewardship team. Methods This quality improvement study was performed in a tertiary care hospital in collaboration with the department of cardiothoracic surgery and the hospitals antimicrobial stewardship team following a revision of the standard for surgical antimicrobial prophylaxis including 1029 patients who underwent cardiac surgery. 582 patients receiving cefuroxime and 447 patients receiving cefazolin respectively were compared without altering any other preventative perioperative measures including its postoperative duration of less than 24 h. Adherence and surgical site infections were compiled and analysed. Results A complete adherence was achieved. Overall surgical site infections occurred in 37 (3.6%) of the cases, 20 (3.4%) in cefuroxime patients and 17 (3.8%) in cefazolin patients (p value = 0.754). No statistically significant differences could be found in any of the primary endpoints, but there was a trend towards less deep sternal wound infections in the cefazolin group. Conclusions The study supports the role of antimicrobial stewardship in cardiac surgery and mirrors the success of a multidisciplinary team aiming to minimize adverse events by optimizing antibiotic use.

Does Incisional Negative Pressure Wound Therapy Prevent Sternal Wound Infections?

Background Incisional negative pressure wound therapy has been described as an effective method to prevent wound infections after open heart surgery in several publications. However, most studies have examined relatively small patient groups, only a few were randomized, and some have manufacturer-sponsorship. Most of the studies have utilized Prevena; there are only a few reports describing the PICO incisional negative pressure wound therapy system. Methods We conducted a prospective cohort study involving a propensity score-matched analysis to evaluate the effect of PICO incisional negative pressure wound therapy after coronary artery bypass grafting. A total of 180 high-risk patients with obesity or diabetes were included in the study group. The control group included 772 high-risk patients operated before the initiation of the study protocol. Results The rates of deep sternal wound infections in the PICO group and in the control group were 3.9 and 3.1%, respectively. The rates of superficial wound infections needing operative treatment were 3.1 and 0.8%, respectively. After propensity score matching with two groups of 174 patients, the incidence of both deep and superficial infections remained slightly elevated in the PICO group. None of the infections were due to technical difficulties or early interruption of the treatment. Conclusion It seems that incisional negative pressure wound therapy with PICO is not effective in preventing wound infections after coronary artery bypass grafting. The main difference in this study compared with previous reports is the relatively low incidence of infections in our control group.

177 Pedicled Or Skeletonized Bilateral Internal Mammary Artery Harvesting - A Meta- Analysis and Trial Sequential Analysis

Objective There is varying evidence on the role of skeletonization of internal mammary artery in reducing the risk of sternal wound infections and ischemia following bilateral internal mammary artery grafting. We opt to compare post-operative clinical outcomes of skeletonized bilateral internal mammary artery versus pedicled bilateral internal mammary artery harvesting in patients undergoing coronary artery bypass surgery. Method A comprehensive electronic search was conducted using PubMed/MEDLINE, Scopus, EMBASE, Cochrane database and Google Scholar from inception until 15th June 2020. All studies directly comparing skeletonized and pedicled bilateral internal mammary artery harvesting were included. Meta-analysis and trial sequential analysis was conducted. Results Ten studies consisting of 3728 patients (2098 patients with skeletonized bilateral internal mammary artery grafting and 1630 patients with pedicled bilateral internal mammary artery grafting) were included. Pooled effects analysis and trial sequential analysis reported significantly lower risk of sternal wound infection with skeletonized bilateral internal mammary artery harvesting (OR 0.32, 95% CI 0.20 – 0.51, p < 0.00001). S-BIMA may be associated with lower late mortality, but more information is required to confirm this. Conclusions Skeletonization reduces the risk of sternal wound infections by preserving vasculature as much as possible. This makes it an important technique for use in bilateral internal mammary artery grafting for high-risk patients.

1097 17 Years of Treating Deep Sternal Wound Infections at A Single Institution: Outcomes and Lessons Learned

Introduction Deep sternal wound infections (DSWI) are a serious complication following cardiac surgery that comprise of any infection penetrating the subcutaneous tissue of the sternum. DSWI have been found to increase mortality and worsen prognostic outcomes following surgery. Method We conducted a retrospective cohort study using hospital e-records from 2000 to 2017 of all adult patients operated on with a median sternotomy at our institution. Univariate and multivariate analysis along with mortality and Kaplan-Meier survival curves compared the DSWI population against the remaining study population, using SPSS-25 software. Results Of 15521 total patients in the study, 145 (0.9%) suffered a DSWI. Variables that were associated with DSWI included age at operation (p = 0.019), gender (p = 0.007), BMI (p = 0.001), diabetes (p < 0.0001), renal disease (p = 0.008), operative urgency (p = 0.007), type of operation (p = 0.02), Euroscore (p = <0.0001), bypass-time (p = 0.038) and crossclamp-time (p = 0.008). A logistic regression encompassing significant variables revealed that gender (p = 0.031 CI 1.45-1.96), BMI (p < 0.0001 CI 1.03-1.10), diabetes (p = 0.007 CI 1.20-3.67) and type of operation (p = 0.018 CI 1.23-1.87) remained significant when covariate contribution was eliminated. DSWI subgroup mortality was insignificant at 30 days (3.4%vs2.9%, p = 0.68) but significantly worse at 90 days (8.3%vs3.7%, p = 0.004) and at 1 year (17.2%vs5.4%, p < 0.0001). Kaplan-Meier analysis depicted a significantly worse survival distribution for the DSWI population compared to rest of study (Log-Rank<0.05). Conclusions At our centre, DSWI are attributable to certain modifiable and set demographics and contribute heavily to medium-term mortality. A better understanding of DSWI risk factors may pinpoint those at risk and benefit the multidisciplinary team to ultimately reduce the rate of DSWI.