Bilateral Versus Single Internal Mammary Artery Grafting in the Elderly: Long-Term Survival Benefit

Twenty-year outcomes of minimally invasive direct coronary artery bypass surgery: The Leipzig experience

OBJECTIVE

Minimally invasive direct coronary artery bypass (MIDCAB) surgery involving left anterior descending coronary artery grafting with the left internal thoracic artery through a left anterior small thoracotomy is being routinely performed in some specified centers for patients with isolated complex left anterior descending coronary artery disease, but very few reports regarding long-term outcomes exist in literature. Our study was aimed at assessing and analyzing the early and long-term outcomes of a large cohort of patients who underwent MIDCAB procedures and identifying the effects of changing trends in patient characteristics on early mortality.

METHODS

A total of 2667 patients, who underwent MIDCAB procedures between 1996 and 2018, were divided into 3 groups on the basis of the year of surgery: group A, 1996-2003 (n = 1333); group B, 2004-2010 (n = 627) and group C, 2011-2018 (n = 707). Groupwise characteristics and early postoperative outcomes were compared. Long-term survival for all patients was analyzed and predictors for late mortality were identified using Cox proportional hazards methods.

RESULTS

The mean age was 64.5 ± 10.9 years and 691 (25.9%) patients were female. Group C patients (log EuroSCORE I = 4.9 ± 6.9) were older with more cardiac risk factors and comorbidities than groups A (log EuroSCORE I = 3.1 ± 4.5) and B (log EuroSCORE I = 3.5 ± 4.7). Overall and groupwise in-hospital mortality was 0.9%, 1.0%, 0.6%, and 1.0% (P = .7), respectively. Overall 10-, 15-, and 20-year survival estimates for all patients were 77.7 ± 0.9%, 66.1 ± 1.2%, and 55.6 ± 1.6%, respectively.

CONCLUSIONS

MIDCAB can be safely performed with very good early and long-term outcomes. In-hospital mortality remained constant over the 22-year period of the study despite worsening demographic profile of patients.

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.

Impact of Bilateral versus Single Internal Thoracic Artery Grafting on the Long-Term Survival in Adults: A Systematic Review

Objective

To analyse the survival of patients who had undergone bilateral internal thoracic artery grafting versus those with single internal thoracic artery grafting from the available literature. Moreover, this study will review the available literature regarding which of the two techniques seems to be the safest with long-term survival and reduced mortality rates.

Methods

A literature search of the databases was conducted to retrieve studies that fall under the study design of cohort and randomized controlled clinical trials in English from January 2015 to July 2021. Finally, seven studies were selected: four cohort studies and three other from a randomized trial.

Results

The cohort studies revealed that bilateral internal thoracic artery grafting is associated with lower mortality rates and better long-term survival outcomes than single internal thoracic artery grafting, while the ART randomized controlled clinical trials showed that there is no significant difference in mortality rates between both the coronary artery bypass grafting techniques. However, all studies concluded that bilateral internal thoracic artery grafting is associated with a higher frequency of deep sternal wound infections.

Conclusion

The discrepancy in results between the cohort studies and randomized controlled clinical trial remains persistent. However, the stated advantages of bilateral internal thoracic artery grafting are not strong enough to convince surgeons to alter their practice and the wide magnitude of expectations from the ART study was reckoned as inadequate. This may well be due to the presence of limited criteria for bilateral internal thoracic artery grafting in identifying the impact on survival of extended arterial revascularization, and there is a new colossal expectation from the ongoing randomized trial based on multiple arterial grafting versus single arterial grafting.

The use of free versus in situ right internal mammary artery in coronary artery bypass grafting

INTRODUCTION

Coronary artery bypass grafting (CABG) continues to be the most commonly performed cardiac surgical procedure in the world. The use of multiarterial grafting may confer a long-term survival benefit over the use of vein grafts. However, there is a paucity of data comparing the use of in situ versus free right internal mammary artery (RIMA) in isolated CABG.

METHODS

Patients that underwent isolated CABG between 2010 and 2018 where RIMA was used in addition to a left internal mammary artery graft. Patients with prior cardiac surgery or percutaneous coronary intervention were excluded. Propensity matching was used for subanalysis. Mortality and major adverse cardiac and cerebrovascular events (MACCE) were analyzed with Kaplan-Meier survival curves and Cox multivariable regression. Heart failure-specific readmissions were assessed with cumulative incidence curves with Fine and Gray competing risk regression.

RESULTS

A total of 667 patients underwent isolated CABG. Of those, 422 had free RIMA and 245 had in situ RIMA utilized. Mortality was similar between cohorts (p = 0.199) with 5-year mortality rates of 6.6% (free) and 4.1% (in situ). MACCE was similar between cohorts, with 5-year event rates of 33.6% and 33.9% (p = 0.99). RIMA style was not a significant predictor of any outcome.

CONCLUSION

There was no difference in long-term mortality, complications, MACCE, or heart failure readmissions when comparing a contemporary cohort of patients undergoing isolated CABG utilizing RIMA as a conduit. These data may allow surgeons to consider using RIMA either as an in situ or a free conduit.

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.

Survival benefit from a second arterial conduit to the circumflex circulation persists in elderly after coronary artery bypass surgery

BACKGROUND

This retrospective propensity matched study investigated the impact of age on the survival benefit from a second arterial conduit to the left-sided circulation.

METHODS

Data for isolated coronary artery bypass surgery were collected from October 2004 to March 2014. All patients with an internal mammary artery graft to left anterior descending artery and additional arterial or venous graft to the circumflex circulation were included. Propensity matching was used to balance co-variates and generate odds of death for each observation. Odds ratios (venous vs. arterial) were charted against age.

RESULTS

The in-hospital mortality rate was 1.12% (arterial) vs. 1.24% (venous) (p = 0.77). The overall 10-year survival was 74.6% (venous) vs. 82.6% (arterial) (p = 0.001). A total of 1226 patients were successfully matched to the venous or arterial (second conduit to circumflex territory after left internal mammary artery to left anterior descending artery) cohorts. Odds ratio for death (venous to arterial) showed a linear decremental overall survival benefit for the second arterial graft to circumflex circulation with increasing age.

CONCLUSIONS

The survival benefit of a second arterial graft persists through all age groups with a gradual decline with increasing age over the decades. Elderly patients should not be denied a second arterial graft to the circumflex circulation based on age criterion alone.

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.

National Trends and Geographic Variation in Bilateral Internal Mammary Artery Use in the United States

BACKGROUND

The goal of this study was to characterize the adoption rate and regional variation in bilateral internal mammary artery (BIMA) use during coronary artery bypass grafting (CABG) in the United States.

METHODS

Observational study of 100% sample of fee-for-service Medicare beneficiaries aged 65 years or older, continuously enrolled in Parts A and B from 2009 to 2014 (n = 162,860,439). Rates of beneficiaries receiving a BIMA versus single internal mammary artery (SIMA) during CABG are expressed per 1,000 beneficiaries and aggregated by Hospital Referral Region (HRR). An HRR is a validated unit for quantifying regional variation in health care.

RESULTS

The absolute national rate of BIMA use declined during the study period from 0.21 claims per 1,000 beneficiaries in 2009 to 0.13 in 2014 (p < 0.001). When indexed to overall CABG volume, no change was seen in the frequency of BIMA use over time (p = 0.883). SIMA use ranged from 1.3 to 8.5 claims per 1,000 Medicare beneficiaries, whereas BIMA use ranged from 0 to 1.5 (p < 0.001). A significant correlation was found between regional volume of SIMA use and likelihood of BIMA use (correlation coefficient 0.673, p < 0.001). Although both SIMA and BIMA use correlated with regional volume of diagnostic cardiac catheterization, the correlation was stronger for SIMA use (correlation coefficient 0.962 versus 0.682, p < 0.001).

CONCLUSIONS

Over the past 5 years, no growth was seen in BIMA use among Medicare beneficiaries, and the frequency of BIMA use during CABG remained low. There was significant regional variation in BIMA use, however, which demonstrates opportunity for continued growth of BIMA grafting.

Female sex is not a risk factor for post procedural mortality in coronary bypass surgery in the elderly: A secondary analysis of the GOPCABE trial

OBJECTIVE

Female sex is considered a significant risk in cardiac surgery and is included in the majority of scores for risk assessment. However, the evidence is controversial and older women undergoing cardiac surgery have not specifically been investigated. We assessed the influence of female sex on surgical risk (30-day mortality) in a secondary analysis of the GOPCABE trial (German Off-Pump Coronary Artery Bypass grafting in the Elderly (GOPCABE) trial, comparing on- to off-pump) and also evaluated its impact on risk prediction from commonly used risk scores.

METHODS

We performed logistic regression analyses on the GOPCABE trial population, where patients were randomized to either on- or off-pump CABG. The study was performed in 12 cardiac surgery centers in Germany and analyzed 2394 patients having undergone CABG at age ≥75 years (1187 on-pump, 1207 off-pump). Of the 2394 patients, 755 (32%) were women. The logistic EuroSCORE and the German KCH score were calculated as expected (E) mortality and values were compared to observed (O) 30-day mortality (O/E ratio).

RESULTS

There was no difference in mortality or major cardiovascular adverse events after 30 days between men and women for both on- and off-pump CABG (men: on- vs. off-pump OR = 0.90, 95%-CI: [0.63;1.27]; women: on- vs. off-pump OR = 1.07, 95%-CI: [0.62;1.87]). Therefore, groups were combined for further analyses. Both men and women had considerable and similar comorbidities. Expected mortality was significantly higher for women than for men (logistic EuroSCORE: 8.88±6.71% vs. 7.99±6.69%, p = 0.003; KCH score: 4.42±3.97% vs. 3.57±3.65%, p = 0.001). However, observed mortality rates (O) tended to be even lower in women (2.1% vs. 3.0%). The O/E ratio was closer to 1 in men than in women (0.84 vs. 0.47). Excluding female sex from the risk models increased O/E ratio to 0.69.

CONCLUSIONS

Female sex is not a risk factor in coronary bypass surgery in the GOPCABE population. The result is the same for on- and off-pump surgery. Since female sex is a component of most risk scores, the findings may identify a potential inaccuracy in current surgical risk assessment, specifically for elderly women.

TRIAL REGISTRATION

Clinicaltrials.gov GOPCABE trial No. NCT00719667.

Cardiac surgery 2015 reviewed

For the year 2015, almost 19,000 published references can be found in PubMed when entering the search term "cardiac surgery". The last year has been again characterized by lively discussions in the fields where classic cardiac surgery and modern interventional techniques overlap. Lacking evidence in the field of coronary revascularization with either percutaneous coronary intervention or bypass surgery has been added. As in the years before, CABG remains the gold standard for the revascularization of complex stable triple-vessel disease. Plenty of new information has been presented comparing the conventional to transcatheter aortic valve implantation (TAVI) demonstrating similar short- and mid-term outcomes at high and low risk, but even a survival advantage with transfemoral TAVI at intermediate risk. In addition, there were many relevant and interesting other contributions from the purely operative arena. This review article will summarize the most pertinent publications in the fields of coronary revascularization, surgical treatment of valve disease, heart failure (i.e., transplantation and ventricular assist devices), and aortic surgery. While the article does not have the expectation of being complete and cannot be free of individual interpretation, it provides a condensed summary that is intended to give the reader "solid ground" for up-to-date decision-making in cardiac surgery.

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

BACKGROUND

Although bilateral internal mammary artery (BIMA) grafting is performed with increasing regularity in elderly patients, whether it is truly beneficial, and therefore indicated, in these patients remains uncertain. We retrospectively investigated early and late outcomes of BIMA grafting in patients aged ≥75 years.

METHODS AND RESULTS

We identified 460 patients aged ≥75 years from among 2,618 patients who underwent either single internal mammary artery (SIMA) grafting (n=293) or BIMA grafting (n=107). Early outcomes did not differ between the SIMA and BIMA patients (30-day mortality: 1.7% vs. 0%, P=0.39; sternal wound infection: 1.0% vs. 4.7%; P=0.057). Late outcomes, 10-year survival in particular, were improved in the BIMA group (36.6% vs. 48.1%, P=0.033). In the analysis of the results in propensity score-matched groups (196 patients in the SIMA group, 98 patients in the BIMA group), improved 10-year survival was documented in the BIMA group (34.8% vs. 47.6%, P=0.030). Cox proportional regression analysis showed SIMA usage (non-use of BIMA) to be a predictor for late mortality (hazard ratio: 0.65, 95% confidence interval: 0.43-0.98, P=0.042). We further compared outcomes between the total non-elderly patients (n=2,158) and total elderly patients (n=460). BIMA usage was similar, as was 30-day mortality (1.0% vs. 1.3%, respectively).

CONCLUSIONS

A survival advantage, with no increase in early mortality, can be expected from BIMA grafting in patients aged ≥75 years. (Circ J 2016; 80: 1756-1763).

Multiple arterial grafting for coronary revascularization: "A guide for the perplexed"

The surgical literature abounds with articles extolling the benefits of arterial grafting for patients with advanced coronary artery disease in need of surgical revascularization. However, examination of clinical performance demonstrates that extensive use of arterial grafting is highly selective and generally uncommon. Rather than to merely repeat multiple excellent recent literature reviews, the goal herein is to provide the reader with a guide to the evaluation of the current literature as well as to suggest fruitful areas for further research. More circumspect understanding of the strengths and weaknesses of our current knowledge base will not only help to explain the current apparent disparity between theory and practice but will hopefully inform future decision-making and patient care.