Bilateral Internal Mammary Artery Research Articles

Impacts of Skeletonized Bilateral Internal Mammary Artery Bypass Grafting on the Risk of Deep Sternal Wound Infection.

This single-center study aimed to evaluate the incidence of deep sternal wound infection (DSWI) following skeletonized bilateral internal mammary artery (BIMA) harvest in a Chinese cohort. Using propensity score matching, this study also provided a present-day assessment of the impacts of skeletonized BIMA grafting versus skeletonized single internal mammary artery (SIMA) grafting on early outcomes.From January 2014 to December 2017, 2403 eligible patients were entered into either a BIMA group (n = 368) or a SIMA group (n = 2035). The incidence of DSWI was recorded. Analysis of early outcomes was further performed for propensity score-matched (1:1) cohorts.The BIMA group received a similar incidence of DSWI as did the SIMA group (1.6% versus 0.9%, P = 0.247). No significant differences between subgroup diabetic-BIMA, subgroup nondiabetic-BIMA, subgroup diabetic-SIMA, and subgroup nondiabetic-SIMA were found regarding the incidence of DSWI (2.0%, 1.4%, 1.0%, and 0.7%, respectively; P > 0.05 between groups). After matching, treatment type (skeletonized BIMA grafting versus skeletonized SIMA grafting) was not an independent risk factor for postoperative DSWI (OR = 1.309, 95% CI 0.897-2.714, P = 0.704) or predictors of other early outcomes. Additionally, the two matched groups shared similar early outcomes (including postoperative DSWI), regardless of whether or not the merger with diabetes (all P > 0.05).Skeletonized BIMA harvest as compared with skeletonized SIMA harvest was not associated with an increased risk of DSWI, regardless of whether or not the merger with diabetes. Patients with skeletonized BIMA grafting received similar surgical mortality and major postoperative morbidity as did matched patients with skeletonized SIMA grafting.

Does Bilateral Internal Mammary Artery Grafting Better Suit Patients With Diabetes? - Two Different Ways to Explore Outcomes.

This analysis compared short-term mortality, sternal wound infection (SWI), and long-term survival outcomes in diabetic patients who underwent coronary artery bypass grafting (CABG) with bilateral (BIMA) vs. single (SIMA) internal mammary artery, as well as in diabetic vs. non-diabetic patients undergoing BIMA grafting.Methods and Results:Nineteen studies were included in the study, covering 21,143 different patients. Of these patients, 6,464 underwent CABG with BIMA, 10,264 underwent CAGB with SIMA, 11,584 had diabetes, and 6,717 did not. Compared with SIMA, BIMA had a significantly lower risk of in-hospital mortality (odds ratio [OR] 0.73, P=0.02), but a significantly higher risk of SWI (OR 1.30, P=0.04). However, compared with non-diabetic patients who underwent CABG with BIMA, diabetic patients with BIMA grafting did not have significantly higher risks of either mortality (OR 1.22, P=0.53) or SWI (OR 1.10, P=0.72). No significant differences were detected with different harvesting techniques. Longer term, BIMA was associated with a significantly higher rate of survival than SIMA (hazard ratio [HR] 0.76, P<0.001). Results from the 2 types of comparisons indicate that BIMA is a preferable option for diabetic patients, even though it has a higher risk of infection. CABG with BIMA is also associated with a long-term survival benefit.

Robotic off-pump totally endoscopic hand-sewn coronary artery bypass using in-situ bilateral internal mammary artery

The tips and tricks of robotic totally endoscopic coronary artery bypass have not been fully described. In this video tutorial, we present our experience and provide information about technical considerations and other details that will help support surgeons interested in starting a totally-endoscopic coronary artery bypass surgery program.

Blood consumption in total arterial coronary artery bypass grafting

BackgroundAccumulating evidence consistently demonstrates that blood transfusion in cardiac surgery is related to decreased short- and long-term survival. We aimed to evaluate periprocedural blood loss and transfusion rates in elective, isolated total arterial coronary artery bypass grafting (CABG) using exclusively skeletonized bilateral internal mammary arteries (IMAs).MethodsWe identified 1011 consecutive patients with coronary artery disease who underwent CABG between 1/2007 and 12/2014. Of them, 595 patients who presented preoperative hemoglobin levels >9md/dl and underwent elective, isolated CABG for multi-vessel coronary artery disease were included in the study population. 419 patients (70.4%) received total arterial CABG using skeletonized bilateral IMAs, in 176 patients (29.6%) mixed CABG (single IMA & saphenous vein) was performed. Propensity score adjustment using 16 variables was applied to control for treatment effect.ResultsIn patients undergoing total arterial CABG, heterologous blood transfusion could be avoided in 87.8% of all cases. Propensity score adjusted results showed a significantly lower incidence of erythrocyte concentrate transfusion in patients undergoing total arterial CABG compared to mixed CABG (odds ratio 2.74, 95% confidence interval 1.38–5.43, P = 0.004). There were no statistically significant differences in the rates of thrombocyte concentrate (P = 0.39) and fresh frozen plasma transfusions (P = 0.07).ConclusionsIn this study, patients who underwent elective, isolated total arterial CABG using exclusively skeletonized bilateral IMAs showed reduced transfusion rates of erythrocyte concentrates compared to mixed CABG using a combination of single IMA and saphenous vein grafts. No evidence for a higher incidence of complications was found with a total arterial approach.

Contemporary outcomes of coronary artery bypass grafting in obese patients.

This study evaluated the impact of obesity on outcomes of coronary artery bypass grafting (CABG) with particular attention to cases using bilateral internal mammary arteries (BIMAs). Patients undergoing isolated CABG from 2011 to 2017 at a single institution were categorized by body mass index (BMI): 18.5 to 24.9 kg/m2 , 25.0 to 29.9 kg/m2 , 30.0 to 34.9 kg/m2 , and ≥35 kg/m2 , respectively. The primary outcomes were mortality and readmission. Subgroup analysis was performed on CABGs using BIMAs. Adjusted Cox model curves were used for survival analyses and cumulative incidence function for readmissions. A total of 4980 patients underwent CABG with BMIs of 18.5 to 24.9 kg/m2 (17.8%; n = 884), 25.0 to 29.9 kg/m2 (35.0%; n = 1745), 30.0 to 34.9 kg/m2 (27.5%; n = 1368), and ≥35 kg/m2 (19.7%; n = 983), respectively. Patients with BMI 18.5 to 24.9 kg/m2 had a higher overall Society of Thoracic Surgeons predicted risk of mortality. Adjusted survival was similar across BMI groups, and readmission risk was highest in those with a BMI of 18.5 to 24.9 kg/m2 (P = .01). Increasing BMI was associated with higher rates of postoperative deep sternal wound infection (DSWI). CABG was performed with BIMA in 820 (16%). In patients undergoing CABG with BIMA use, there were no differences in survival, readmissions, or DSWI rates between BMI groups. CABG, including with the use of BIMA, can be performed in obese patients without an increased risk of mortality or hospital readmission out to 5 years. Although rates of postoperative DSWI increase with increasing BMI, this finding did not appear to be magnified in patients with BIMA, although the sample size was limited in this subanalysis. These data support the notion that BIMA use should not be precluded in the obese.

Is the Use of BIMA in CABG Sub-Optimal? A Review of the Current Clinical and Economic Evidence Including Innovative Approaches to the Management of Mediastinitis.

Bilateral internal mammary artery (BIMA) in coronary artery bypass grafting (CABG) has traditionally been limited. This review looks at the recent outcome data on BIMA in CABG focusing on the management of risk factors for mediastinitis, one of the potential barriers for more extensive BIMA utilization. A combination of pre-, intra- and postoperative strategies are essential to reduce mediastinitis. Limited data indicate that the incidence of mediastinitis can be reduced using closed incision negative-pressure wound therapy as a part of these strategies with the possibility of offering patients best treatment options by extending BIMA to those with a higher risk of mediastinitis. Recent economic data imply that the technology may challenge the current low uptake of BIMA by reducing the short-term cost differentials between single internal mammary artery and BIMA. Given that most published randomized controlled trials and meta-analyses of observational long-term outcome data favor BIMA, if short-term complications of BIMA including mediastinitis can be controlled adequately, there may be opportunities for more extensive use of BIMA leading to improved long-term outcomes. An ongoing study looking at BIMA in high-risk patients may provide evidence to support the hypothesis that mediastinitis should not be a factor in limiting the use of BIMA in CABG.

Prevention of Sternal Dehiscence Following Use of Bilateral Internal Mammary Arteries in OPCAB

Purpose: We harvested bilateral Internal Mammary Arteries and made LIMA-RIMA Y in all the patients undergoing OPCAB at our center irrespective of the presence or absence of various risk factors for sternal dehiscence. The purpose of this study was to find an effective way of sternal closure in patients undergoing OPCAB with both the Internal Mammary Arteries harvested for grafting. Method: The patients who did not have any risk factors were placed in group I and all of them had a standard six wire closure of sternotomy. The patients having any risk factors were placed in group II. The patients in group II were randomized by including every alternate patient from group II to subgroup II A and every other alternate patient from group II to subgroup II B. Patients in subgroup II A again had a standard closure of sternotomy while in patients of subgroup II B bilateral Robiscek repair and four-five interlocking figure of eight wires were used for closure of sternotomy. Results: The patients who had risk factors for sternal dehiscence had higher risk for sternal dehiscence as compared to patients without any risk factors if bilateral Internal Mammary Arteries were harvested for OPCAB. But if we used bilateral Robiscek repair with four to five interlocking figure of eight wires for sternal closure then the rate of sternal complications in the patients with risk factors for sternal dehiscence was not more than the patients without risk factors. Conclusion: We can harvest bilateral Internal Mammary Arteries for OPCAB without fear of sternal complications even in patients with high risk for sternal dehiscence if we use bilateral Robiscek repair with four to five interlocking figure of eight wires for sternal closure.

Early and long-term outcomes of bilateral inthernal thoracic artery grafting for coronary artery bypass surgery

To evaluate safety of coronary artery bypass surgery using bilateral internal mammary artery and effectiveness of this procedure in long-term postoperative period. The study involved 129 patients who underwent CABG for the period 2006-2007. There were 2 groups of patients depending on surgical strategy: group 1 (n=61) - double IMA harvesting, group 2 (n=68) - CABG using single IMA. Short-term results were compared using standard statistical methods. Long-term survival was compared using Kaplan-Meyer method. Revascularization index was 3.014±0.76 in the 1st group and 3.1±0.73 in the 2nd group (p>0.05). In-hospital mortality was 0% and 1.47%, respectively (p> 0.05). A 10-year survival was 95.1% and 91.2%, respectively (p>0.05). Freedom from cardiac events (mortality, myocardial infarction, recurrent angina pectoris) was significantly different (95% vs. 81%, p<0.05). Significantly lower rate of adverse cardiac events in long-term postoperative period in comparison with conventional CABG clearly demonstrates high quality of life after coronary artery bypass surgery using bilateral internal mammary artery for a long time. Therefore, this procedure is preferred in patients with coronary artery disease.

Complete myocardial revascularization in patients with multiple-vessel coronary artery disease and partial or complete absence of the grafts for coronary artery bypass surgery

Complete revascularization in patients with multiple-vessel coronary artery disease and partial or complete absence of the grafts is still actual problem for cardiac surgeons. The main causes of the absence of conduits for coronary artery bypass surgery are aging of population, increased incidence of repeated coronary artery bypass surgery and prevalence of varicose vein disease of the lower extremities. The most perspective approaches characterized by acceptable early and long-term postoperative outcomes are bilateral internal mammary artery grafting, sequential bypass including autoarterial grafts, as well as hybrid revascularization methods. However, treatment strategy is individualized in each patient.

Successful Endovascular Therapy for Bilateral Internal Mammary Artery Injuries Caused by Cardiopulmonary Resuscitation: A Case Report

Successful Endovascular Therapy for Bilateral Internal Mammary Artery Injuries Caused by Cardiopulmonary Resuscitation: A Case Report

Validation and Performance Comparison of Two Scoring Systems Created Specifically to Predict the Risk of Deep Sternal Wound Infection after Bilateral Internal Thoracic Artery Grafting

Background: The Gatti and the bilateral internal mammary artery (BIMA) scores were created to predict the risk of deep sternal wound infection (DSWI) after bilateral internal thoracic artery (BITA) grafting. Methods: Both scores were evaluated retrospectively in two consecutive series of patients undergoing isolated multi-vessel coronary surgical procedures-i.e., the Trieste (n = 1,122; BITA use, 52.1%; rate of DSWI, 5.7%) and the Besançon cohort (n = 721; BITA use, 100%; rate of DSWI, 2.5%). Baseline patient characteristics were compared between the two validation samples. For each score, the accuracy of prediction and predictive power were assessed by the area under the receiver-operating characteristic curve (AUC) and the Goodman-Kruskal gamma coefficient, respectively. Results: There were significant differences between the two series in terms of age, gender, New York Heart Association functional class, chronic lung disease, left ventricular function, surgical priority, and the surgical techniques used. In the Trieste series, accuracy of prediction of the Gatti score for DSWI was higher than that of the BIMA score (AUC, 0.729 vs. 0.620, p = 0.0033). The difference was not significant, however, in the Besançon series (AUC, 0.845 vs. 0.853, p = 0.880) and when only BITA patients of the Trieste series were considered for analysis (AUC, 0.738 vs. 0.665, p = 0.157). In both series, predictive power was at least moderate for the Gatti score and low for the BIMA score. Conclusions: The Gatti and the BIMA scores seem to be useful for pre-operative evaluation of the risk of DSWI after BITA grafting. Further validation studies should be performed.

Sternal wound closure in the current era: the need of a tailored approach.

Median sternotomy remains the most common access to perform cardiac surgery procedures. However, the experience of the operating surgeon remains a crucial factor during sternal closure to avoid potential complications related to poor sternal healing, such as mediastinitis. Considering the lack of major randomized controlled trials and the heterogeneity of the current literature, this narrative review aims to summarize the different techniques and approaches to sternal closure with the aim to investigate their reflections into clinical outcomes and to inform the choice on the most effective closure method after median sternotomy. A literature search through PubMed, Embase, EBSCO, Cochrane database of systematic reviews, and Web of Science from its inception up to April 2019 using the following search keywords in various combinations: sternal, sternotomy, mediastinitis, deep sternal wound infection, cardiac surgery, closure. Single wire fixation methods, at present, seems the most useful method to perform sternal closure in routine patients, although patients with a fragile sternum might benefit more from a figure-of-eight technique. In high-risk patients (e.g. chronic pulmonary disease, obesity, bilateral internal mammary artery harvesting, diabetes, off-midline sternotomy), rigid plate fixation is currently the most effective method, if available; alternatively, weave techniques could be used. The choice among the sternal closure techniques should be mainly inspired and tailored on the patient's characteristics, and correct judgement and experience play a pivotal role. A decisional algorithm has been proposed as an attempt to overcome the absence of specific guidelines and to guide the operative approach. This operative approach might be used also in non-cardiac procedure in which median sternotomy is required, such as in case of thoracic surgery.

Skeletonisation contributing to a reduction of sternal wound complications: a retrospective study in OPCAB patients

BackgroundSternal wound complications (SWC) are a rare but potentially life-threatening complication after coronary artery bypass grafting (CABG) surgery. Especially the use of bilateral IMA (BIMA) grafts as opposed to single IMA (SIMA) grafts is associated with an increased risk of SWC. Skeletonised harvesting has been proposed to reduce this risk. The purpose of this study was to retrospectively investigate the effect of skeletonisation on SWC after off-pump coronary artery bypass grafting (OPCAB) in a centre with a high volume of off-pump procedures and high frequencies of BIMA.MethodsFrom January 2010 to November 2016, 1900 consecutive patients underwent OPCAB surgery at the University Hospitals of Leuven. The first group (n = 1487) received non-skeletonised IMA grafts, whereas the second group (n = 413) received skeletonised grafts. Optimal wound management was pursued in all patients. A new four-grade classification for SWC was developed. Incidence and grade of SWC as well as overall survival were assessed.ResultsAnalysis of diabetic patients showed a lower incidence of SWC in the skeletonised (12/141, 8.5%) compared to the non-skeletonised group (82/414, 19.8%) [odds ratio 0.46, 95% confidence interval (0.23;0.88), p = 0.019] as well as a lower grade [0.45 (0.24;0.871), p = 0.018]. There was no significant effect on overall survival [0.67 (0.19;2.32), p = 0.529]. Subanalysis of this population revealed that the observed effects were most prominent in patients receiving BIMA grafts, with 6/56 (10.7%) SWC in the skeletonised and 62/252 (24.6%) in the non-skeletonised group [0.37 (0.15;0.90), p = 0.028 for incidence], as well as a lower grade [0.36 (0.15;0.88), p = 0.025]. These advantages were not significant in diabetic patients receiving SIMA grafts nor in the full study population.ConclusionsThis study, using a more sensitive classification of SWC, shows in a large group of patients that, in combination with optimized wound management, the skeletonisation technique is associated with a clear reduction in the incidence and grade of SWC in diabetic patients receiving BIMA grafts. This encourages the extension of BIMA use in OPCAB to this risk population.

Total arterial revascularization strategies: A meta-analysis of propensity score-matched observational studies.

We explored the current evidence available on total arterial revascularization (TAR) carrying out a meta-analysis of propensity score-matched studies comparing TAR versus non-TAR strategy. PubMed, EMBASE, and Google Scholar were searched for propensity score-matched studies comparing TAR vs non-TAR. The generic inverse variance method was used to compute the combined hazard ratio (HR) of long-term mortality. The Der-Simonian and Laird method were used to compute the combined risk ratio (RR) of 30-day mortality, deep sternal wound infection, and reoperation for bleeding. Eighteen TAR vs non-TAR matched populations were included. Meta-analysis showed a significant benefit in terms of long-term survival of the TAR group over the non-TAR group (HR: 0.73; 95% confidence interval [CI]: 0.68-0.78). Better long-term survival over non-TAR strategy was confirmed by both subgroups: TAR withthe bilateral internal mammary artery (BIMA) and TAR without BIMA. Meta-regression suggests that TAR may offer a higher protective survival effect in diabetic patients (coefficient: -0.0063; 95% CI: -0.01 to 0.0006), when carried out with BIMA (coefficient: -0.15; 95% CI: -0.27 to -0.03) or using three arterial conduits (coefficient: -0.12; 95% CI: -0.25 to 0.007). A TAR strategy carried out using BIMA, differently from TAR without BIMA, increases the risk of deep sternal infection (RR: 1.44; 95% CI: 1.17-1.77). TAR provides a long-term survival benefit compared with the non-TAR strategy. Also, compared with TAR without BIMA, TAR with BIMA may offer a higher protective long-term survival effect at the expense of a higher risk of sternal deep wound infection.

Rigid Primary Sternal Fixation Reduces Sternal Complications Among Patients at Risk

The optimal sternal closure technique in patients at elevated risk after cardiac surgery has not been elucidated. Between January 2006 and July 2015, 15,048 consecutive adult patients underwent cardiac surgery via median sternotomy using cardiopulmonary bypass. Rigid sternal fixation using 3 separate techniques (peristernal polyether ether-ketone banding, titanium plating, and stainless steel multibraided cables with cannulated screws) was used in 1111 patients (group A), whereas conventional peristernal/transsternal wiring was used in 13,937 patients (group B). Predictors of deep sternal wound infection or dehiscence were evaluated, and propensity score analysis was used to create 2 matched groups; 1050 group A patients (94.5%) were matched to group B patients. Mean time to presentation was 31 ± 70.3 days (median, 19) after surgery. There was a decreased incidence of deep sternal wound infection or dehiscence among propensity score-matched group A compared with group B patients (1.9% vs 2.7%, P= .13), although it was not statistically significant. On multivariate analysis, group A was associated with a 33% relative risk reduction of deep sternal wound infection or dehiscence (odds ratio, 0.67; 95% confidence interval, 0.48-0.94; P= .02); this was entirely due to a protective effect associated with polyether ether-ketone banding (odds ratio, 0.4; 95% confidence interval, 0.3-0.7; P= .0002). In the subgroup of bilateral internal mammary artery grafting patients (n= 886), there was a strong protective trend associated with preventative sternal fixation, although it was not statistically significant (odds ratio, 0.3; 95% confidence interval, 0.09-1.09; P= .06). Primary sternal fixation in patients at risk of sternal complications is associated with decreased sternal infection and/or dehiscence. Primary fixation may expand the use of bilateral internal mammary artery grafting to patient populations at increased risk for sternal complications.

Outcome of Robot-Assisted Bilateral Internal Mammary Artery Grafting via Left Pleura in Coronary Bypass Surgery.

Studies are extremely limited for the investigation of the clinical outcome of da Vinci robot-assisted bilateral internal mammary artery (BIMA) grafting in coronary artery bypass grafting (CABG) surgery. This study aimed to explore the short-term outcome of da Vinci robot-assisted BIMA grafting through the left pleural space. Relevant data were collected from patients with multi-vessel coronary artery disease receiving two kinds of CABG: a group of patients receiving da Vinci robot-assisted CABG with BIMA grafting, and another group of patients receiving sternotomy CABG with BIMA grafting. Primary endpoints, which included cardiovascular and renal endpoints, were analyzed between the groups using the chi-square test, analysis of variance test, and Kaplan–Meier analysis. Compared with the conventional group (n = 22), the robotic group (n = 22) had a significantly longer operation time (12.7 ± 1.7 vs. 8.5 ± 1.5 hours; p < 0.01) and a marginally lower mean of serum creatinine at baseline (1.2 ± 0.3 vs. 2.0 ± 1.7 mg/dL; p = 0.04). Primary endpoints (5, 22.7% vs. 12, 54.5%; p = 0.03) and renal endpoints (1, 4.5% vs. 7, 31.8%; p = 0.02) at six months were significantly reduced in the robotic group compared with the conventional group. There were no differences in cardiovascular endpoints at six months between the groups (1, 4.5% vs. 0; p = 1.00). The data showed that da Vinci robot-assisted BIMA grafting was safe, with equal cardiovascular events and lowered renal events at six months, as compared to conventional sternotomy BIMA grafting, despite the longer procedure time. The short-term study suggests that da Vinci robot-assisted BIMA grafting may be considered a favorable surgical option for patients with severe coronary artery disease.

Early clinical outcomes of minimally invasive coronary surgery-total arterial coronary revascularization

Objective: To summarize the early experience and clinical value of minimally invasive coronary surgery-total arterial coronary revascularization (MICS-TACR) through the left anterior small incision. Methods: Between May 2015 and June 2018, a total of 31 consecutive cases [21 males and 10 females, aged (63.2±9.3) years] in Peking University Third Hospital who were performed MICS-TACR with bilateral internal mammary artery and radial artery were enrolled. Meanwhile, 1 489 cases of conventional median sternal incision off-pump coronary artery bypass grafting (OPCABG) were matched as control group. According to exclusion criteria and matching score, 90 cases [55 males and 35 females, aged (63.8±9.5) years] were selected as the control group, and the perioperative data of the two groups were compared. All patients in MICS-TACR group underwent postoperative angiography and the graft patency was evaluated. Results: There were no statistically significant differences in baseline data between the two groups. The perioperative blood transfusion of MICS-TACR group was less than control group [0(0,0) U vs 0(0,4) U, P=0.003]. There were no statistically significant differences in operative mortality, intraoperative and postoperative intra-aortic balloon pump (IABP) and extracorporeal membrane oxygenation (ECMO) use, re-operation rate, perioperative major adverse cardiac and cerebrovascular events (MACCE), new-onset renal failure, atrial fibrillation, and multiple organ failure between the two groups. Postoperative angiography showed that there was no significant difference in the patency rate between the MICS-TACR group and control group(all P>0.05). Conclusion: Total arterial coronary revascularization can be successfully accomplished under the left anterior small incision, and the early clinical outcome is satisfied.

Clinical outcomes of total arterial off-pump coronary revascularization in patients with left ventricular dysfunction

Objective: To compare the advantages and disadvantages of total arterial revascularization (TAR) and conventional off-pump coronary artery bypass (OPCAB) grafting in patients with left ventricular dysfunction (LVD). Methods: Between January 2008 and March 2015, 76 patients who were scheduled to undergo selective OPCAB were selected for cardiac surgery in Zhongshan Hospital, Fudan University. The left ventricular ejection fraction of enrolled patients was less than 35%. Among those patients, 38 patients in TAR group underwent total arterial OPCAB with bilateral internal mammary artery, left and/or right radial artery, and another 38 patients in control group underwent conventional OPCAB with left internal mammary artery and great saphenous vein. The clinical data of all patients were collected. The follow-up was performed within 36 months. Results: There was no significant difference in preoperative clinical data between the two groups (all P>0.05). Additionally, there was no significant difference in the application rate of internal mammary artery, positive inotropic drugs and intra-aortic balloon pump (IABP) use between the two groups (all P>0.05). The operation time of TAR group was longer than that of control group [(278.3±31.2) min vs (196.7±19.1) min, P<0.01]. There was no significant difference in perioperative mortality between the two groups (5.3% vs 7.9%, P=0.64). The volume of operative drainage and blood transfusion in TAR group increased significantly at 24 hours after operation [(895.0±236.2) ml vs (585.4±172.5) ml, (656.3±84.4) ml vs (433.3±62.9) ml, both P<0.01]. There was no significant difference in perioperative complications such as heart, kidney and lung failure between the two groups (all P>0.05). At 12 months after operation, there were no significant differences in survival rate, cardiac death rate, angina recurrence, myocardial infarction, re-treatment rate of revascularization, re-hospitalization rate from cardiac insufficiency, graft patency rate, cardiac function and echocardiographic data between the two groups (all P>0.05). From 24 to 36 months after operation, all the above indexes in TAR group were better than those in control group except for echocardiographic data (all P<0.05). Conclusions: For LVD patients, the early clinical efficacy of the two surgical methods is similar, but for the long-term outcomes, the whole arterial OPCAB operation is obviously superior. However, the shortcomings of total arterial OPCAB are that operative drainage and the use of blood products increased significantly after operation.

Abstract 171: User Beware: Understanding the Adjusted Estimates of Propensity Score Methods

Background: Propensity score methods are used in observational studies to compensate for the lack of random allocation by balancing measured baseline characteristics between treated and untreated patients. Yet default implementations of propensity score methods may lead to contradictory findings. Our goal was to illustrate differences in treatment effect estimates produced using propensity score methods such as matching and inverse probability weighting (IPW). Methods: We used data from a retrospective analysis of the Northern New England Cardiovascular Disease Study Group registry that studied reintervention after single internal mammary artery (SIMA) versus bilateral internal mammary artery (BIMA) conduit use in 41,481 coronary artery bypass grafting (CABG) procedures from 1992-2014. Results: The mean duration of follow-up was 13.2 (IQR: 7.4-17.7) years. In our standard multivariable Cox regression analysis, the adjusted HR for reintervention was 0.83 (95% confidence interval (CI): 0.75-0.92) in patients receiving BIMA compared to SIMA (Table). The 1:1 propensity matched analysis (HR=0.79, 95% CI: 0.69-0.91) and IPW estimate among the treated (HR=0.83, 95% CI: 0.75-0.92) show a similar protective treatment effect of BIMA use on reintervention. However, the IPW approach for the overall population effect unusually showed no difference between BIMA and SIMA on reintervention-free survival (HR=1.08, 95% CI: 0.94-1.24). Conclusions and Relevance: The adjusted HR for reintervention after BIMA versus SIMA use in CABG was remarkably different for the two IPW estimates. This difference is attributed to the population represented by the two IPW approaches- the IPW among the treated estimate represents the effect in the average study population, whereas the IPW in the treated represents the effect in the treated population alone. Determining how the study population is balanced (weighted to look like the overall study population versus treated group) is a large driver of treatment effect, and a key element of propensity score methods. Ultimately, the treatment effect estimate desired should drive the choice of propensity score adjustment method.

AIncisional Negative Pressure Wound Therapy (INPWT) for Coronary Artery Bypass Grafting Patients

Background: Surgical site infections are major complications of coronary artery bypass grafting using bilateral internal thoracic arteries. In this study we reviewed the results of using INPWT for high risk patients with coronary artery bypass grafting (CABG) using bilateral internal mammary arteries. Patients and methods: From January 2013 to December 2016, patients with coronary artery bypass grafting using bilateral mammary arteries were enrolled in this study. Patients were from Kasr El-Einy, Beni-Suef and Fayoum University Hospitals. The total number was 427 patients, where INPWT was used in 161 patient, and conventional sterilized dressing was done in 266 patients. 2 groups were matched for statistical analysis, the first group was the control and the second group was where INPWT was used. Results: The results related to sternal wound infections were similarly attributed to the conventional group (10.9%) and the INPWT group (10.2%) (P=1.00). Patients treated with INPWT had less rate of infection than those with conventional dressing (5.5% versus 10.2%, P= 0.210), this difference was not statistically significant. Interaction tests also showed comparable results for SSI (surgical site infections) among patients with or without significant co-morbidities. Conclusion: This study suggests that the use of INPWT did not decrease the incidence of sternal wound infections in patients who had CABG surgery using bilateral internal mammary harvesting (BIMA). A larger randomized study is needed to evaluate the efficacy of this technique.