Is Bilateral Internal Mammary Arterial Grafting Beneficial for Patients Aged 75 Years or Older?

Sternal wound infections following internal mammary artery grafts for a coronary bypass: A meta-analysis

The meta-analysis aims to evaluate and compare the sternal wound infections following internal mammary artery grafts for a coronary bypass. Examinations comparing bilateral internal mammary artery to single internal mammary artery for coronary artery bypass grafting were among the meta-analyses from various languages that met the inclusion criteria. Using dichotomous random- or fixed-effect models, the results of these investigations were examined, and the Odd Ratio (OR) with 95% confidence intervals (CIs) was computed. A total of 31 examinations from 2001 to 2023 were recruited for the current analysis including 181 503 personals with coronary artery bypass grafting. Bilateral internal mammary artery had significantly higher sternal wound infection (OR, 1.51; 95% CI, 1.37-1.68, p < 0.001), superficial sternal wound infection (OR, 1.72; 95% CI, 1.16-2.56, p = 0.007), deep sternal wound infection (OR, 1.62; 95% CI, 1.41-1.86, p < 0.001), sternal wound infection in diabetics (OR, 1.48; 95% CI, 1.16-1.90, p = 0.002), sternal wound infection in elderly (OR, 1.38; 95% CI, 1.22-1.57, p < 0.001), sternal wound infection in pedicled preparation (OR, 1.70; 95% CI, 1.30-2.23, p < 0.001) and sternal wound infection in skeletonized preparation (OR, 1.40; 95% CI, 1.09-1.81, p = 0.009) compared to single internal mammary artery in personals with coronary artery bypass grafting. Bilateral internal mammary artery grafting is linked to a higher risk of impaired wound healing, particularly in diabetic individuals, elderly, pedicled preparation, and skeletonized preparation. Nevertheless, caution should be exercised while interacting with its values since examinations were performed by different surgeons with different skills on different types of personals.

Bilateral internal thoracic artery coronary grafting: risks and benefits in elderly patients

AIMS

Whether bilateral internal thoracic artery (BITA) grafting benefits elderly patients in coronary artery bypass grafting (CABG) remains unclear since they tend to have a limited life expectancy and severe comorbidities. We aim to evaluate the outcomes of BITA vs. single internal thoracic artery (SITA) grafting in elderly patients.

METHODS AND RESULTS

A meta-analysis was performed by database searching until May 2021. Studies comparing BITA and SITA grafting among elderly patients were included. One randomized controlled trial, nine propensity score matching, and six unmatched studies were identified, with a total of 18 146 patients (7422 received BITA grafting and 10 724 received SITA grafting). Compared with SITA grafting, BITA grafting had a higher risk of deep sternal wound infection (DSWI) [odds ratio: 1.67; 95% confidence interval (CI): 1.22-2.28], and this risk could not be significantly reduced by the skeletonization technique. Meanwhile, BITA grafting was associated with a higher long-term survival [hazard ratio: 0.83; 95% CI: 0.77-0.90], except for the octogenarian subgroup. Reconstructed Kaplan-Meier survival curves revealed 4-year, 8-year, and 12-year overall survival rates of 85.5%, 66.7%, and 45.3%, respectively, in the BITA group and 79.3%, 58.6%, and 34.9%, respectively, in the SITA group. No significant difference was observed in early mortality, perioperative myocardial infarction, perioperative cerebral vascular accidents, or re-exploration for bleeding.

CONCLUSION

Compared with SITA grafting, BITA grafting could provide a long-term survival benefit for elderly patients, although this benefit remained uncertain in octogenarians. Meanwhile, elderly patients who received BITA were associated with a higher risk of DSWI and such a risk could not be eliminated by the skeletonization technique.

Meta-Analysis of Bilateral Versus Single Internal Thoracic Artery Grafting in Patients ≥70 Years of Age

The optimal choice of graft material in patients ≥70 years of age undergoing coronary artery bypass grafting remains unknown. A systematic review of literature was conducted by searching PubMed, Embase, Web of Science, and Cochrane Library databases for original publications that compared bilateral internal thoracic artery (BITA) grafting with single internal thoracic artery grafting in patients ≥70 years of age. Data were extracted by 2 independent investigators and meta-analyzed with the use of random effects. A total of 10 studies, including 11,185 patients, met the inclusion criteria. No differences in early mortality and morbidity, with the exemption of sternal wound complications which were more frequently observed in the BITA group (odds ratio 1.72, 95% 1.00 to 2.96 confidence interval [CI], p = 0.05; propensity score-matched population odds ratio 1.58, 95% CI 1.09 to 2.29, p = 0.02), were observed. Overall survival was superior in the overall patient population (hazard ratio [HR] 0.76, 95% CI 0.66 to 0.86, p <0.001), after applying a blanking period of 3 months to the overall patient population (HR 0.77, 95% CI 0.64 to 0.92, p = 0.005) as well as in the matched population (HR 0.72, 95% CI 0.58 to 0.89, p = 0.002); in all cases, a benefit was readily seen within a few years after surgery. The difference in freedom from major adverse cardiac and cerebrovascular events failed to reach statistical significance (overall patient population HR 0.55, 95% CI 0.27 to 1.13, p = 0.10; matched population HR 0.52, 95% CI 0.23 to 1.16, p = 0.11). In conclusion, BITA grafting can be safely performed in patients ≥70 years of age as late clinical benefits are expected to manifest themselves readily within a few years after surgery.

Multiple versus single arterial grafting in the elderly: a meta-analysis of randomized controlled trials and propensity score studies

INTRODUCTION

The benefit of adding a second arterial conduit is still controversial, mainly in specific subgroups. We conducted a meta-analysis of randomized controlled trials (RCTs) and propensity score (PS) studies comparing survival and early results in elderly patients who underwent coronary artery bypass grafting (CABG) with multiple (MAG) versus single arterial grafting (SAG).

EVIDENCE ACQUISITION

MEDLINE, Web of Science and Cochrane Library were used to find relevant literature (1960-April 2020). Survival at a ≥ 1-year follow-up and early outcomes were evaluated. Outcomes were collected from matched samples or PS adjusted analysis: hazard ratio (HR) along with their variance, frequencies or odds ratios. Random effect models were used to compute combined statistical measures and 95% confidence intervals (CI) through generic inverse variance method (time-to-event) or Mantel-Haenszel method (binary events).

EVIDENCE SYNTHESIS

Eleven PS cohorts and 1 RCT comprising > 18,800 patients older than 70 (>6200 MAG and >12,500 SAG) were included in this meta-analysis. MAG was associated with lower long-term mortality (pooled HR: 0.81, 95%CI: 0.72-0.91, p<0.01, I2=64%) in the absence of higher risk of early mortality (pooled OR: 0.74, 95%CI: 0.44 to 1.25, p=0.27, I2=0%). In a meta-regression, MAG survival advantage was more pronounced in studies with a higher MAG usage rate (β = -0.0052, p=0.021).

CONCLUSIONS

Current evidence suggests that advanced age should not limit MAG's use considering its benefits in long-term survival. Of note, an individualized patient selection for this approach is warranted.

Bilateral vs Single Internal Mammary Artery Grafts for Coronary Artery Bypass in the United States

BACKGROUND

The use of the bilateral internal mammary artery (BIMA) in coronary artery bypass grafting remains controversial. The objective of this study was to investigate the long-term outcomes using the BIMA vs the single internal mammary artery (SIMA) in the United States.

METHODS

Medicare beneficiaries who underwent primary isolated coronary artery bypass surgery using the SIMA or BIMA from 1999 to 2010 were included in this retrospective study, with follow-up through 2014. Greedy matching algorithms were used for 1:4 matching on propensity score based on age, gender, year of surgery, and comorbidities. Kaplan-Meier survival analyses were performed. The primary outcome was death from any cause.

RESULTS

A total of 1,156,339 and 25,005 patients who were 72 ± 7.6 years of age and 70.3 ± 7.9 years of age underwent primary isolated coronary artery bypass surgery using SIMA and BIMA, respectively. Matching created comparable groups with 95,780 SIMA and 24,160 BIMA patients. Matched median survival using SIMA vs BIMA was 11.8 vs 12.4 years (P < .001) and 9.6 vs 10 years in diabetic patients (P = .006), respectively. At 10 years of follow-up, the respective survival rates of using SIMA vs BIMA were 58.3% vs 61.1%, respectively. The stratified matched median survival using SIMA vs BIMA with 1, 2, 3, and 4 or more aortocoronary bypasses were 11.8 vs 12.3 years (P = .005), 11.7 vs 12.5 years (P < .001), 11.9 vs 12.3 years (P = .01), and 11.4 vs 12 years (P = .02), respectively.

CONCLUSIONS

Primary isolated coronary artery bypass surgery using the BIMA rather than the SIMA was associated with improved long-term survival. This survival advantage was independent of aortocoronary bypass grafts or patient diabetes status.

Robustness of the Comparative Observational Evidence Supporting Class I and II Cardiac Surgery Procedures

Background

Current cardiac surgery guidelines give Class I and II recommendations to valve‐sparing root replacement over the Bentall procedure, mitral valve (MV) repair over replacement, and multiple arterial grafting with bilateral internal thoracic artery based on observational evidence. We evaluated the robustness of the observational studies supporting these recommendations using the E value, an index of unmeasured confounding.

Methods and Results

Observational studies cited in the guidelines and in the 3 largest meta‐analyses comparing the procedures were evaluated for statistically significant effect measures. Two E values were calculated: 1 for the effect‐size estimate and 1 for the lower limit of the 95% CI. Thirty‐one observational studies were identified, and E values were computed for 75 effect estimates. The observed effect estimates for improved clinical outcomes with valve‐sparing root replacement versus the Bentall procedure, MV repair versus replacement, and grafting with bilateral internal thoracic artery versus single internal thoracic artery could be explained by an unmeasured confounder that was associated with both the treatment and outcome by a risk ratio of more than 16.77, 4.32, and 3.14, respectively. For MV repair versus replacement and grafting with bilateral internal thoracic artery versus single internal thoracic artery, the average E values were lower than the effect sizes of the other measured confounders in 33.3% and 60.9% of the studies, respectively. For valve‐sparing root replacement versus the Bentall procedure, no study reported effect sizes for associations of other covariates with outcomes.

Conclusions

The E values for observational evidence supporting the use of valve‐sparing root replacement, MV repair, and grafting with bilateral internal thoracic artery over the Bentall procedure, MV replacement, and grafting with single internal thoracic artery are relatively low. This suggests that small‐to‐moderate unmeasured confounding could explain most of the observed associations for these procedures.

Wound Infection after CABG Using Internal Mammary Artery Grafts: A Meta-Analysis

BACKGROUND

 Internal mammary arteries show better long-term patency rates than venous grafts. The use of both mammary arteries is associated with a higher risk of sternal wound infections. This meta-analysis was designed to assess the incidence of a wound healing disorder after bilateral compared with single mammary artery bypass grafting. Compared with existing meta-analysis this paper includes more current literature and one randomized controlled trial.

METHODS

 A literature search was performed using PubMed and the Cochrane Library. The quality of the articles was assessed by the Newcastle Ottawa Scale. The odds ratio was used as a measure of the chance of developing a wound healing disorder after bilateral internal mammary artery (BIMA) surgery. Meta-analyses were performed for different subgroups.

RESULTS

 Twenty studies met the quality criteria, including one randomized controlled trial. The use of both mammary arteries significantly increased the risk of superficial (odds ratio [OR] 1.72) and deep (OR 1.75) wound healing disorder in the total population (OR 1.80) as well as in the diabetic subgroup (OR 1.38) and with both preparation techniques. The increased risk with BIMA grafting was present independently of the preparation technique (pedicled: OR 1.89, skeletonized: OR 1.37).

CONCLUSION

 Bilateral internal mammary artery grafting, especially in high-risk and diabetic patients, is associated with an increased risk of wound healing impairment. Skeletonized preparation does not eliminate the elevated wound healing disorder risk after BIMA use.

Short-term results of bilateral internal mammary arterial grafting for patients aged 60-75 years - a retrospective study

Background

Bilateral internal mammary artery (BIMA) grafting has a good long-term survival rate and graft patency rate, but it is only recommended in young patients due to its high technical requirements and high incidence of sternal complications. Previous studies indicated that BIMA grafting has a significant benefit in patients aged 50–59 years, but this benefit does not extend to patients aged > 60 years. Thus, this study was designed to analyse the immediate artery graft function, short-term (3 months) results, and experience in preventing sternal complications for BIMA grafting in elderly patients (60–75 years old).

Methods

Clinical records and echocardiographic and coronary artery computed tomography angiography data of 155 patients who underwent BIMA grafting for coronary artery disease between 2015 and 2017 in our hospital were analysed retrospectively to summarise the operative experience and short-term (3 months) results. Patients were divided into two groups: Group A (n = 95), aged < 60 years and Group B (n = 60), aged 60–75 years. The operation time, aortic clamp time, and cardiopulmonary bypass time of these two groups were compared to analyse the operation difficulty and the flow and pulsatility index were compared to analyse the immediate artery graft function. The left ventricular end-diastolic dimension (LVEDD) and left ventricular ejection fraction (LVEF) of these two groups were compared to analyse heart function.

Results

There were no significant differences in the operation time, aortic clamp time, and cardiopulmonary bypass time as well as the flow and pulsatility index between these two groups (P > 0.05). There was no significant difference in the incidence of sternal wound complications, graft occlusion, and other common complications 3 months post-BIMA grafting between these two groups (P > 0.05). Furthermore, there was no significant difference in LVEDD and LVEF between the groups 3 months post-operation (P > 0.05).

Conclusions

BIMA grafting was safe and effective for older patients (60–75 years). Similar to younger patients (< 60 years), BIMA grafting in elderly patients (60–75 years) can also achieve a satisfactory short-term (3 months) result. Thus, advanced age (60–75 years) should not be a contraindication for BIMA grafting.

Bilateral internal thoracic artery versus single internal thoracic artery: a meta-analysis of propensity score-matched observational studies

The lack of benefit in terms of mid-term survival and the increase in the risk of sternal wound complications published in a recent randomized controlled trial have raised concerns about the use of bilateral internal thoracic artery (BITA) in myocardial revascularization surgery. For this reason, we decided to explore the current evidence available on the subject by carrying out a meta-analysis of propensity score-matched studies comparing BITA versus single internal thoracic artery (SITA). PubMed, EMBASE and Google Scholar were searched for propensity score-matched studies comparing BITA versus SITA. The generic inverse variance method was used to compute the combined hazard ratio (HR) of long-term mortality. The DerSimonian and Laird method was used to compute the combined risk ratio of 30-day mortality, deep sternal wound infection and reoperation for bleeding. Forty-five BITA versus SITA matched populations were included. Meta-analysis showed a significant benefit in terms of long-term survival in favour of the BITA group [HR 0.78; 95% confidence interval (CI) 0.71-0.86]. These results were consistent with those obtained by a pooled analysis of the matched populations comprising patients with diabetes (HR 0.65; 95% CI 0.43-0.99). When compared with the use of SITA plus radial artery, BITA did not show any significant benefit in terms of long-term survival (HR 0.86; 95% CI 0.69-1.07). No differences between BITA and SITA groups were detected in terms of 30-day mortality or in terms of reoperation for bleeding. Compared with the SITA group, patients in the BITA group had a significantly higher risk of deep sternal wound infection (risk ratio 1.66; 95% CI 1.41-1.95) even when the pooled analysis was limited to matched populations in which BITA was harvested according to the skeletonization technique (risk ratio 1.37; 95% CI 1.04-1.79). The use of BITA provided a long-term survival benefit compared with the use of SITA at the expense of a higher risk of sternal deep wound infection. The long-term survival advantage of BITA is undetectable when compared with SITA plus radial artery.

Total Arterial Off-Pump Coronary Artery Bypass Grafting: A 10-Year Experience

Background:

Arterial grafts had better mid-term and long-term patency than saphenous vein grafts in coronary artery bypass grafting (CABG). We summarized our experience with total arterial off-pump coronary artery bypass grafting (OPCAB) and assessed the early clinical results, surgical complications, and follow-up.

Methods:

From January 2007 to May 2017, 508 coronary artery disease patients undergoing total arterial OPCAB were enrolled. Clinical features, approaches, outcomes of surgical treatments, and follow-up data of these patients were studied retrospectively. A total of 122 patients underwent single left internal mammary artery (IMA)-left anterior descending artery grafts, whereas the other 386 patients underwent multiple vessel grafts.

Results:

The average distal anastomosis was 2.34 ± 0.97 (range: 1–4). All the patients were discharged from hospital except one died. A total of 457 (90.32%) patients were followed up. In the 4-, 7-, and 10-year follow-up groups, the rate of death from any cause was 1.19%, 6.47%, and 10.67%; rate of cardiac death was 0.60%, 2.88%, and 3.33%; rate of repeat revascularization was 0.00%, 3.60%, and 8.67%; rate of ischemic symptoms was 1.79%, 7.91%, and 11.33%; and incidence of stroke was 2.38%, 4.32%, and 6.67%, respectively. Poor medication adherence was observed in 9.38% of the follow-up population.

Conclusions:

Total arterial OPCAB with bilateral IMA, radial artery, and right gastroepiploic artery grafting yielded satisfactory early and midterm outcomes in this patient group, without a significant increase in early mortality or morbidity. Moreover, the long-term outcomes are also positive.

Bilateral Internal Mammary Artery Bypass Grafting: Sternal Wound Infection in High-Risk Population. Should Sternal Infection Scare Us?

Background

Bilateral internal mammary arteries (BIMAs) remain underused in coronary artery bypass grafting (CABG), especially in elderly, diabetic, and obese patients. This study investigated incidence of sternal wound infection (SWI), sternal instability (SI), and reintervention for bleeding (RIB) in this high-risk population.

Methods

A single-center retrospective observational study was performed in "Grand Hôpital de Charleroi, Gilly, Belgium." A total of 319 patients undergoing CABG from December 2011 to December 2015 were included. Three main outcome measures (SWI, SI, and RIB) were investigated in obese vs nonobese, diabetic vs nondiabetic, and elderly vs younger patients.

Results

In all, 14 SWI, 11 SI, and 6 RIB were discounted. Death rate was as follows: SWI: 2/14 vs 17/305 (P = .178), SI: 2/11 vs 17/308 (P = .081), and RIB: 2/6 vs 17/313 (P = .004). In obese (n = 113) vs nonobese (n = 206) patients, there was no difference for SWI (P = .263), SI (P = .565), and RIB (P = .332). In diabetic (n = 118) vs nondiabetic (n = 201) patients, there was no difference for SWI (P = .642), SI (P = .497), and RIB (P = .298). In elderly (n = 62) vs younger (n = 257) patients, there was no difference for SWI (P = .619), SI (P = .915), and RIB (P = .385).

Conclusions

Obesity, age, and diabetes treated by insulin (or not) do not seem to be risk factors for developing SWI, SI, or RIB in patients receiving a CABG using BIMA. Nevertheless, mortality was higher in RIB group.

Use Rate and Outcome in Bilateral Internal Thoracic Artery Grafting: Insights From a Systematic Review and Meta-Analysis

Background

This meta‐analysis was designed to assess whether center experience affects the short‐ and long‐term results and the relative benefits of bilateral internal thoracic artery grafting (BITA) for coronary artery bypass grafting.

Methods and Results

MEDLINE and EMBASE were searched to identify all articles reporting the outcome of BITA in patients undergoing coronary artery bypass grafting. The BITA center experience was gauged according to the percentage use of BITA in the institutional overall coronary artery bypass grafting population (%BITA). The primary outcome was long‐term all‐cause mortality. Secondary outcomes were operative mortality, perioperative myocardial infarction, perioperative stroke, deep sternal wound infections (DSWIs), and major postoperative adverse event. The rates of the primary and secondary outcomes were calculated after adjusting for %BITA. Primary and secondary outcomes were also compared between the BITA and the single internal thoracic artery arms in the adjusted studies. Meta‐regression was used to evaluate the effect of %BITA on the primary and secondary outcomes. Thirty‐four studies (27 894 patients undergoing BITA) were included. In the pooled analysis, the incidence rate for long‐term mortality was 2.83% (95% confidence interval, 2.21%–3.61%). %BITA was significantly and inversely associated with long‐term mortality and the rate of DSWI. In the pairwise comparison, %BITA was significantly and inversely associated with the risk of long‐term mortality and DSWI in the group undergoing BITA.

Conclusions

BITA series with higher %BITA report significantly lower long‐term mortality and DSWI rate as well as higher long‐term survival advantage and lower relative risk of DSWI in their BITA cohort. These findings suggest that a specific volume‐outcome relationship exists for BITA grafting.

Unmeasured Confounders in Observational Studies Comparing Bilateral Versus Single Internal Thoracic Artery for Coronary Artery Bypass Grafting: A Meta-Analysis

Background

Observational studies suggest a survival advantage with bilateral single internal thoracic artery (BITA) versus single internal thoracic artery grafting for coronary surgery, whereas this conclusion is not supported by randomized trials. We hypothesized that this inconsistency is attributed to unmeasured confounders intrinsic to observational studies. To test our hypothesis, we performed a meta‐analysis of the observational literature comparing BITA and single internal thoracic artery, deriving incident rate ratio for mortality at end of follow‐up and at 1 year. We postulated that BITA would not affect 1‐year survival based on the natural history of coronary artery bypass occlusion, so that a difference between groups at 1 year could not be attributed to the intervention.

Methods and Results

We searched MEDLINE and Pubmed to identify all observational studies comparing the outcome of BITA versus single internal thoracic artery. One‐year and long‐term mortality for BITA and single internal thoracic artery were compared in the propensity‐score–matched (PSM) series, that is, the form of observational evidence less prone to confounders. Thirty‐eight observational studies (174 205 total patients) were selected for final comparison. In the 12 propensity‐score–matched series (34 019 patients), the mortality reduction for BITA was similar at 1 year and at the end of follow‐up (incident rate ratio, 0.70; 95% confidence interval, 0.60–0.82 versus 0.77; 95% confidence interval, 0.70–0.85; P for subgroup difference=0.43).

Conclusions

Unmeasured confounders, rather than biological superiority, may explain the survival advantage of BITA in observational series.