Sternal wound infection after coronary artery bypass grafting using bilateral internal thoracic artery: prevention and management

Reduction of Sternal Infection in Off-pump CABG by Modified Pedicle Harvesting

Invited Commentary

Bilateral Internal Thoracic Artery Harvest and Deep Sternal Wound Infection in Diabetic Patients

Bilateral Internal Mammary Artery Grafting and Risk of Sternal Wound Infection: Evidence From Observational Studies

We previously introduced techniques to harvest and use the right internal thoracic artery in minimally invasive coronary artery bypass grafting (CABG) via a single left thoracotomy for revascularization with bilateral internal thoracic arteries (BITA). We report our short-term outcomes of patients who underwent minimally invasive CABG using BITA and a single internal thoracic artery (SITA). Consecutive patients who underwent minimally invasive CABG using BITA or SITA at a Japanese medical center between February 2012 and December 2015 were reviewed retrospectively. Preoperative, intraoperative and 30-day postoperative outcomes were analysed. Perioperative data for the SITA cohort is presented to provide a context in which the outcomes of the BITA cohort can be evaluated. A total of 25 and 37 patients underwent BITA and SITA revascularization, respectively. The mean duration of the operation was longer in the BITA group than in the SITA group (265 ± 104 vs 336 ± 73 min). There were no deaths in the BITA group and one death in the SITA group. There were no strokes in either cohort, and new haemodialysis was required in one patient in each group. All BITA grafts were harvested without major complications and were all patent on computed tomography angiograms 1 week following the operations. BITA can be safely harvested in a reproducible manner under direct vision via a small left thoracotomy. The potential advantages of minimally invasive CABG using BITA, although yet to be established, include a long-term survival benefit conferred by BITA grafts and elimination of the risk of sternal wound infection, in addition to the established advantages of minimally invasive coronary artery surgery. This approach has the potential for further optimization with hybrid revascularization strategies.

Sternal wound infections (SWIs) can be subdivided into two types, superficial or deep, that require different treatments. The clinical diagnosis of superficial SWI is normally easy to perform, whereas the involvement of deep tissues is frequently difficult to detect. Therefore, there is a need for an imaging study that permits the assessment of SWIs and is able to distinguish between superficial and deep SWI. The present work was a prospective study aiming to evaluate the role of technetium-99m hexamethylpropylene amine oxime (99mTc-HMPAO) labelled leucocyte scan in SWI management. Twenty-eight patients with suspected SWIs were included in the study. On the basis of clinical examination they were subdivided into three groups: patients with signs of superficial SWI (group 1), patients with signs of superficial SWI and suspected deep infection (group 2) and patients with suspected deep SWI without superficial involvement (group 3). Ten patients previously submitted to median sternotomy, but without suspected SWI, were also included in the study as a control group (group 4). All patients with suspected SWI had bacteriological examinations of wound secretion, if present. In addition 99mTc-HMPAO labelled leucocyte scan was performed in all patients. The patients of groups 1, 2 and 3 were treated on the basis of the clinical signs and microbiological findings, independently of the scintigraphic results. The patients of group 4 did not receive treatment. The final assessment of infection was based on histological and microbiological findings or on long-term clinical follow-up. Sensitivity, specificity, accuracy and positive and negative predictive values for scintigraphic and non-scintigraphic results were calculated. In the diagnosis of superficial and deep SWI, clinical and microbiological examination (combined) yielded, respectively, a sensitivity of 68.7% and 100%, a specificity of 77.3% and 80.8%, an accuracy of 73.7% and 86.8%, a positive predictive value of 68.7% and 70.6% and a negative predictive value of 77.3% and 100%. The scintigraphic results obtained in superficial SWI yielded a sensitivity of 56.2%, a specificity of 90.9%, an accuracy of 76.3%, a positive predictive value of 81.8% and a negative predictive value of 74.1%, while, by contrast, in deep SWI all of these values were 100%. Therefore, one can conclude that 99mTc-HMPAO labelled leucocyte scan permits accurate diagnosis of deep SWI, solving the main clinical problem in this field. In the present study the categorisation of patients without taking into account 99mTc-HMPAO labelled leucocyte planar scan findings caused a non-negligible number of cases of superficial SWI to be treated as though they were deep SWI. This "overestimation" led to unnecessary surgery, increased and prolonged use of antibiotics with more (higher) toxicity and additional expense.

Background There is debate whether the use of more arterial grafts during coronary artery bypass graft surgery provides advantages to the standard operation using the left internal thoracic artery plus vein grafts. We review data from the Arterial Revascularisation Trial to determine whether there is support for the multiple arterial graft hypothesis. Methods Patients undergoing coronary artery bypass graft for clinical reasons and who provided written informed consent were randomised to standard coronary artery bypass graft using the single internal thoracic artery or use of bilateral internal thoracic arteries. Additional vein grafts could be used. The primary outcome was all-cause mortality at 10 years and exploratory analyses were carried out to test the multiple arterial graft hypothesis. Results A total of 3102 patients were enrolled (1548 bilateral internal thoracic artery and 1554 single internal thoracic artery). Follow-up to 10 years for vital status was 98% complete. In the bilateral group, 14% of patients received a single internal thoracic artery only and use of radial artery grafts occurred in about 20% of patients in both groups. Aspirin was used in 81% of the patients, beta-blockers in 74%, statins in 90% and angiotensin-converting enzyme inhibitors or angiotensin receptor blockers in 73%. At 10 years, death rates were 20.3% and 21.2% in the bilateral internal thoracic artery and single internal thoracic artery groups, respectively (hazard ratio 0.96, 95% confidence intervals 0.82 to 1.12; p = 0.62) and composite of all-cause mortality, myocardial infarction or stroke 24.9% and 27.3%, respectively (hazard ratio 0.90, 95% confidence interval 0.79 to 1.03; p = 0.12). Exploratory analyses using the ‘as-treated’ approach indicate that outcomes were better in patients who received multiple arterial grafts (adding the right internal thoracic and/or radial arteries) compared with a single arterial graft. This effect appeared to be greater in patients with diabetes and those aged 70 years or less. Use of total arterial grafting without vein grafts may provide the best outcomes. Limitations The elevated cross-over rate between bilateral internal thoracic artery and single internal thoracic artery and the non-randomised use of radial artery grafts may have contributed to a loss of power to detect a difference in mortality between the two groups. Moreover, secondary analyses are prone to bias as they compare non-randomised groups. Conclusions The Arterial Revascularisation Trial is one of the largest long-term studies in cardiac surgery. The primary analysis did not show a mortality benefit for bilateral internal thoracic artery at 10 years, perhaps due to high crossover rates in the bilateral internal thoracic artery group and concomitant use of the radial artery. Secondary analyses suggest a mortality benefit for patients receiving multiple arterial grafts compared with single arterial graft with possible greater effects in patients with diabetes and separately in patients aged 70 years or above. The trial will follow patients to 15 years and the continuing Randomized Comparison of the Clinical Outcome of Single versus Multiple Arterial Grafts trial will further test the multiple arterial graft hypothesis. Trial registration This trial is registered as ISRCTN46552265. Funding This project was funded by the British Heart Foundation, the UK. Medical Research Council and the National Institute for Health and Care Research (NIHR) Efficacy and Mechanism Evaluation programme and will be published in full in Efficacy and Mechanism Evaluation; Vol. 10, No. 7. See the NIHR Journals Library website for further project information.

Effect of bilateral internal thoracic artery harvesting on deep sternal wound infection in diabetic patients: Review of literature

Impact of the second internal thoracic artery on short- and long-term outcomes in obese patients: A propensity score matched analysis

Very Long-term Outcome of Bilateral Internal Thoracic Artery in Diabetic Patients: A Systematic Review and Reconstructed Time-To-Event Meta-analysis

BackgroundBilateral 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.MethodsA 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.ResultsA 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).ConclusionsIn-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.

Contrasting results of recent randomized controlled trials (RCTs) comparing off-pump and on-pump coronary artery bypass graft (CABG) surgery, as well as the lack of evidence for any survival benefit of bilateral internal thoracic artery (ITA) grafting over single ITA use, has intensified the debate about the role of the off-pump technique and bilateral ITA use in CABG surgery. We therefore investigated our 15-year experience in off-pump CABG with bilateral ITA grafting and evaluated temporal trends in preoperative characteristics and postoperative outcomes. Demographic, intra-operative, and outcome data of 1,199 consecutive patients undergoing off-pump CABG with bilateral ITA grafting was prospectively collected in a computerized database. Patients who underwent on-pump cardiac procedures and other extra-cardiac procedures were excluded from this study. Assessment of changes in perioperative characteristics and parameters with time was performed by dividing the whole cohort into three groups (2003-2007, 2008-2012, and 2013-2017) based on the year of surgery. The overall 30-day mortality was 0.6%, with no differences observed between the three time cohorts (0.6%, 0.7%, 0.5%; P=0.8). The perioperative stroke rate for whole cohort was 0.6% and demonstrated a significant reduction in the last two time cohorts (1%, 0.5%, 0.5%; P<0.0001). The overall incidence of deep sternal wound infections was 0.7%, but was marginally higher in the last time-cohort (0.6%, 0.5%, 0.9%; P=0.7). Overall survival for the entire cohort was 92.9%±1% and 78.9%±4% at 5 and 10 years follow-up, respectively. Older age at surgery and presence of peripheral vascular disease were the only predictors of late mortality. Off-pump CABG with bilateral skeletonized ITAs is a safe operation and is associated with a low mortality and morbidity, which can be maintained in high volume center unit over a long period of time. The long-term survival of patients undergoing such an operation is excellent.

Surgical site infection is a common complication following cardiac surgery. Triclosan-coated sutures have been shown to reduce the rate of infections in various surgical wounds, including wounds after vein harvesting in coronary artery bypass grafting patients. Our purpose was to compare the rate of infections in sternotomy wounds closed with triclosan-coated or conventional sutures. A total of 357 patients that underwent coronary artery bypass grafting were included in a prospective randomized double-blind single-center study. The patients were randomized to closure of the sternal wound with either triclosan-coated sutures (Vicryl Plus and Monocryl Plus, Ethicon, Inc., Somerville, NJ, USA) (n = 179) or identical sutures without triclosan (n = 178). Patients were followed up after 30 days (clinical visit) and 60 days (telephone interview). The primary endpoint was the prevalence of sternal wound infection according to the Centers for Disease Control and Prevention (CDC) criteria. The demographics in both groups were comparable, including age, gender, body mass index, and rate of diabetes and smoking. Sternal wound infection was diagnosed in 43 patients; 23 (12.8%) sutured with triclosan-coated sutures compared to 20 (11.2%) sutured without triclosan (p = 0.640). Most infections were superficial (n = 36, 10.1%), while 7 (2.0%) were deep sternal wound infections. There were 16 positive cultures in the triclosan group and 17 in the non-coated suture group (p = 0.842). The most commonly identified main pathogens were Staphylococcus aureus (45.4%) and coagulase-negative staphylococci (36.4%). Skin closure with triclosan-coated sutures did not reduce the rate of sternal wound infection after coronary artery bypass grafting. (clinicaltrials.gov: NCT01212315).

Objectives Despite encouraging late outcomes, the use of bilateral internal thoracic artery (BITA) grafting for myocardial revascularization in diabetic patients remains controversial because of an increased risk of sternal wound complications. In the present study, early- and long-term outcomes of the use of left-sided BITA versus single internal thoracic artery (SITA) grafting in young (< 65 years of age) diabetic patients were reviewed retrospectively. Methods A total of 250 propensity score pair-matched diabetic patients, operated on between February 2000 and December 2011, receiving either BITA (n = 125) or SITA (n = 125) grafting were analyzed retrospectively. In each group, 104 patients were males, and mean age was 60.1 ± 5.3 years. Follow-up was 2.1 to 14.8 years (mean, 9.3 ± 3.5 years) and complete for 100%. Results Incidence of deep sternal wound infection was 2.4 versus 3.2% (p = 0.722). Rethoracotomy due to bleeding occurred in 4.8 versus 3.2% (p = 0.608). The 5-, 10-, and 14-year estimates of survival were 93.4, 76.6, and 67.5% (BITA) versus 89.5, 81.5, and 32.8% (SITA); p = 0.288. Freedom from reangiography/intervention (60.5 vs. 63.9%) during follow-up was comparable (p = 0.507) as well as infarction rate (93.8 vs. 95.1%, p = 0.833) and redoes (p = 0.672, exclusively valve surgery) were comparable. Freedom from thromboembolic or cerebrovascular events did not show any significant differences (94.0 vs. 94.0%, p = 0.78). Multivariate analysis identified poor ejection fraction as predictor for decreased long-term survival. Neither age nor gender or urgency had an influence on long-term mortality. Conclusion Left-sided BITA grafting may be performed routinely even in diabetic patients without increased incidence of postoperative wound-healing complications. Survival rates after 5, 10, and 14 years were comparable for BITA and SITA grafting.

The use of bilateral internal thoracic arteries (BITA) has been associated with improved long-term outcomes following coronary artery bypass graft (CABG) surgery. The objective of this study was to evaluate the impact of BITA use on long-term survival among patients with low ejection fraction (EF) undergoing CABG. Between April 1991 and October 2011, 2035 consecutive patients underwent primary BITA grafting. Among them, there were 129 patients with left ventricular EF ≤40%. During the same time period, 1666 primary CABGs were performed using a single internal thoracic artery (SITA) in patients with EF ≤40%. A propensity score optimal matching algorithm was used to create the matched SITA and BITA groups (n = 111 in each group). Also, Cox regression multivariable analyses were performed to determine the independent risk factors for long-term mortality. The date of death was obtained from provincial vital statistics. There was no difference in operative mortality between matched BITA and SITA (n = 2, 1.8% vs n = 1, 0.9%, respectively, P = 0.6) groups. The mean follow-up was 8.6 ± 5.1 and 7.7 ± 5.5 years for BITA and SITA groups, respectively (P = 0.2). Five-, 10- and 15-year survival rates were 93.7, 77.5 and 59.0% in the matched BITA patients vs 82.8, 68.1 and 65.2% in the matched SITA patients (P = 0.3). In multivariate analysis, the independent risk factors for late mortality among hospital survivors were: insulin-dependent diabetes [adjusted hazard ratio (HR): 3.4, 95% confidence interval (CI): 1.4-8.4, P = 0.008], perioperative intra-aortic balloon pump insertion (HR: 3.2, 95% CI: 1.5-6.9, P = 0.004), postoperative deep sternal wound infection (HR: 7.4, 95% CI: 2.2-24.1, P = 0.001) and neurological complications (HR: 3.5, 95% CI: 1.4-8.4, P = 0.006). Choice of BITA versus SITA was not an independent predictor of long-term mortality (P = 0.3). The use of a second internal thoracic artery (ITA) does not prolong late survival in patients with low EF undergoing CABG compared with a propensity-matched group of SITA graft patients.