Impact of prior percutaneous coronary intervention on the outcome of coronary artery bypass surgery: A multicenter analysis

Follow-Up and Outcome after Coronary Bypass Surgery Preceded by Coronary Stent Implantation

BACKGROUND

 Guidelines on myocardial revascularization define recommendations for percutaneous coronary intervention (PCI) or coronary artery bypass graft (CABG) surgery. Only little information exists on long-term follow-up and quality of life (QoL) after CABG preceded by PCI. The aim of our study was to evaluate the impact of prior PCI on outcome and QoL in patients with stable coronary artery disease who underwent CABG.

METHODS

 In our retrospective study, CABG patients were divided in: CABG preceded by PCI: PCI-first (PCF), and CABG-only (CO) groups. The PCF group was further divided in guideline-conform (GCO) and guideline nonconform (GNC) subgroups, according to the SYNTAX score (2014 European Society of Cardiology [ESC]/European Association for Cardio-Thoracic Surgery [EACTS] guidelines). Thirty days mortality, major adverse cardiac events, and QoL using the European Quality-of-Life-5 Dimensions were evaluated.

RESULTS

 A total of 997 patients were analyzed, of which 784 underwent CABG without (CO), and 213 individuals with prior PCI (PCF). The latter group consisted of 67 patients being treated in accordance (GCO), and 24 in discordance (GNC) to the 2014 ESC/EACTS guidelines. Reinfarction (PCF: 3.8% vs. CO: 1.0%; p = 0.024), re-angiography (PCF: 17.6% vs. CO: 9.0%; p = 0.004), and re-PCI (PCF: 10.4% vs. CO: 3.0%; p < 0.001) were observed more frequently in PCF patients. Also, patients reported better health status in the CO compared to PCF group (CO: 72.48 ± 19.31 vs. PCF: 68.20 ± 17.86; p = 0.01). Patients from the guideline nonconform subgroup reported poorer health status compared to the guideline-conform group (GNC: 64.23 ± 14.56 vs. GCO: 73.42 ± 17.66; p = 0.041) and were more likely to require re-PCI (GNC: 18.8% vs. GCO: 2.4%; p = 0.03). Also, GNC patients were more likely to have left main stenosis (GCO: 19.7% vs. GNC: 37.5%; p < 0.001) and showed higher preinterventional SYNTAX score (GCO: 18.63 ± 9.81 vs. GNC: 26.67 ± 5.07; p < 0.001).

CONCLUSION

 PCI preceding CABG is associated with poorer outcomes such as reinfarction, re-angiography, and re-PCI, but also worse health status and higher rehospitalization. Nevertheless, results were better when PCI was guideline-conformant. This data should impact the Heart Team decision.

Coronary Artery Bypass Graft Surgery After Primary Percutaneous Coronary Intervention in Patients With ST-Elevation Myocardial Infarction

OBJECTIVE

To determine whether primary percutaneous coronary intervention (PPCI) is associated with adverse outcomes following coronary artery bypass graft (CABG) among patients with ST-elevation myocardial infarction (STEMI).

METHODS

Patients presenting with acute STEMI who underwent CABG between September 2015 and November 2020 were included. Among 354 patients, 222 (62.7%) underwent PPCI prior to CABG (PPCI+CABG group) and were compared with the rest of the patients (CABG only group). The effects of PPCI on primary endpoints---including in-hospital mortality, length of stay (LOS), and bleeding events---were investigated using the stabilised inverse probability weighting method (S-IPW). Further, in-hospital mortality in various PPCI subgroups was analysed using univariable regression.

RESULTS

Patients with and without PPCI were comparable regarding their baseline and surgical characteristics, except that those without PPCI were more likely to have left-main disease (29.5% vs 16.2%, p-value=0.003). Among the PPCI+CABG group, 3.6% mortality and 55.9% bleeding events occurred, and the LOS was 7 [5-10] days. The respective figures for the CABG only group were 4.5%, 50.8%, and 7 [6-10.5] days. Primary percutaneous coronary intervention, as a whole, was not significantly associated with either morality (S-IPW odds ratio (S-IPW OR) 0.61; p=0.393), LOS logarithm (S-IPW β -0.050; p=0.403), or bleeding events (S-IPW OR 1.06; p=0.821). Nevertheless, the unadjusted mortality risk was significantly higher in complicated PPCIs compared with the CABG only group (OR 7.50, 95% CI 2.03-27.77); it was also higher among some other PPCI subgroups, albeit non-significantly.

CONCLUSION

This study found that PPCI did not confer additional risk regarding in-hospital mortality, LOS, or bleeding among patients with acute STEMI who underwent CABG. However, some PPCI subgroups, especially those with complicated PPCI, were at increased risk.

Coronary Anastomosis In Stent-Useful to Do When No Other Alternative Is Given?

Background  Many patients being referred for coronary artery bypass grafting have a history of percutaneous coronary intervention (PCI). Case Description  In a patient after multiple PCI of the left anterior descending artery (LAD), repeated in-stent stenosis was diagnosed. The LAD being covered with stents to the periphery, no meaningful anastomosis with stent-free vessel was possible. After thorough discussion with the patient, the referring cardiologist, and our local heart team, an in-stent anastomosis was planned and created, that was found to be angiographically patent 21 months after surgery with the patient free from angina. Conclusion  Without any alternative treatment method given, our approach of in-stent anastomosis confers a good mid-term angiographic result.

Late Myocardial Infarction and Repeat Revascularization after Coronary Artery Bypass Grafting in Patients with Prior Percutaneous Coronary Intervention

Objectives: The aim of the present study was to evaluate the risk of late mortality and major adverse cardiovascular and cerebral events after coronary artery bypass grafting (CABG) in patients with prior percutaneous coronary intervention (PCI). Methods: A total of 2948 patients undergoing isolated CABGs were included in a prospective multicenter registry. Outcomes were adjusted for multiple covariates in logistic regression, Cox proportional hazards analysis and competing risk analysis. Results: In all, 2619 patients fulfilled the inclusion criteria of this analysis. Of them, 2199 (79.1%) had no history of PCI and 420 (20.9%) had a prior PCI. An adjusted analysis showed that a single prior PCI and multiple prior PCIs did not increase the risk of 30-day and 5-year mortality. Patients with multiple prior PCIs had a significantly higher risk of 5-year myocardial infarction (SHR 2.566, 95%CI 1.379–4.312) and repeat revascularization (SHR 1.774, 95%CI 1.140–2.763). Similarly, 30-day and 5-year mortality were not significantly increased in patients with prior PCI treatment of single or multiple vessels. Patients with multiple vessels treated with PCI had a significantly higher risk of 5-year myocardial infarction (SHR 2.640, 95%CI 1.497–4.658), repeat revascularization (SHR 1.648, 95%CI 1.029–2.638) and stroke (SHR 2.215, 95%CI 1.056–4.646) at 5-year. The risk for repeat revascularization was also increased with a prior single vessel PCI, but not for other outcomes. Conclusions: Among patients undergoing CABGs, multiple prior PCIs seem to increase the risk of late myocardial infarction and the need for repeat revascularization, but not the risk of mortality.

Prior percutaneous coronary intervention and outcomes in patients after coronary artery bypass grafting: a meta-analysis of 308,284 patients

Background:

The association between prior percutaneous coronary intervention (PCI) and prognosis after coronary artery bypass grafting (CABG) remains uncertain. We aimed to evaluate the aforementioned association in a meta-analysis.

Methods:

PubMed, Cochrane’s Library, and Embase databases were searched for potential studies. A random-effects model was used for the meta-analysis. Meta-regression was performed to evaluate the influence of study characteristics on the outcomes.

Results:

Thirty-six follow-up studies with 308,284 patients were included, and 40,892 (13.3%) patients had prior PCI. Pooled results showed that prior PCI was associated with higher risks of early (in-hospital or within 1 month) all-cause mortality [odds ratio (OR): 1.26, 95% confidence interval (CI): 1.11–1.44, p = 0.003; I² = 64%] and major adverse cardiovascular events (MACEs; OR: 1.36, 95% CI: 1.12–1.66, p = 0.002, I² = 79%), but not with late (follow-up durations from 1 to 13 years) mortality (OR: 1.03, 95% CI: 0.95–1.13, p = 0.44, I² = 46%) or MACEs (OR: 1.03, 95% CI: 0.97–1.09, p = 0.38, I² = 0%). Meta-regression showed that the study characteristics of patient number, age, sex, diabetic status, and proportion of patients with prior PCI did not affect the outcomes. Sensitivity analyses limited to multivariate studies excluding patients with acute PCI failure showed similar results (early mortality, OR: 1.25, p = 0.003; early MACE, OR: 1.50, p = 0.001; late mortality, OR: 1.03, p = 0.70).

Conclusion:

The current evidence, mostly from retrospective observational studies, suggests that prior PCI is related to poor early clinical outcomes, but not to late clinical outcomes, after CABG.

Factors affecting mortality after coronary bypass surgery: a scoping review

Objectives

Previous research reports numerous factors of post-operative mortality in patients undergoing isolated coronary artery bypass graft surgery. However, this evidence has not been mapped to the conceptual framework of care improvement. Without such mapping, interventions designed to improve care quality remain unfounded.

Methods

We identified reported factors of in-hospital mortality post isolated coronary artery bypass graft surgery in adults over the age of 19, published in English between January 1, 2000 and December 31, 2019, indexed in PubMed, CINAHL, and EMBASE. We grouped factors and their underlying mechanism for association with in-hospital mortality according to the augmented Donabedian framework for quality of care.

Results

We selected 52 factors reported in 83 articles and mapped them by case-mix, structure, process, and intermediary outcomes. The most reported factors were related to case-mix (characteristics of patients, their disease, and their preoperative health status) (37 articles, 27 factors). Factors related to care processes (27 articles, 12 factors) and structures (11 articles, 6 factors) were reported less frequently; most proposed mechanisms for their mortality effects.

Conclusions

Few papers reported on factors of in-hospital mortality related to structures and processes of care, where intervention for care quality improvement is possible. Therefore, there is limited evidence to support quality improvement efforts that will reduce variation in mortality after coronary artery bypass graft surgery.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13019-022-01784-z.

Coronary Artery Bypass Graft Surgery in Patients With Acute Coronary Syndromes After Primary Percutaneous Coronary Intervention: A Current Report From the North-Rhine Westphalia Surgical Myocardial Infarction Registry

Background Coronary artery bypass grafting has remained an important treatment option for acute coronary syndromes, particularly in patients (1) with ongoing ischemia and large areas of jeopardized myocardium, if percutaneous coronary intervention (PCI) cannot be performed; (2) following successful PCI of the culprit lesion with further indication for coronary artery bypass grafting; and (3) where PCI is incomplete, not sufficient, or failed. Methods and Results We aimed to analyze coronary artery bypass grafting outcome following prior PCI in acute coronary syndromes from the North-Rhine-Westphalia surgical myocardial infarction registry comprising 2616 patients. Primary end points were in-hospital all-cause mortality and major adverse cardio-cerebral event. Patients were 68±11 years of age, had 3-vessel and left main-stem disease in 80.4% and 45.3%, presenting a logistic EuroSCORE of 15.1% in unstable angina, 20.3% in non-ST-segment-elevation myocardial infarction, and 23.5% in ST-segment-elevation myocardial infarction. A history of PCI was present in 36.2% and PCI was performed within 24 hours before surgery in 5.2% in unstable angina, 5.9% in non-ST-segment-elevation myocardial infarction, and 16.1% in ST-segment-elevation myocardial infarction. PCI failed in 5.3% in unstable angina, 6.8% in non-ST-segment-elevation myocardial infarction and 17.2% in ST-segment-elevation myocardial infarction, and 28.8% of patients presented with cardiogenic shock. In-hospital mortality without PCI was 7.4%, but increased to 8.7% with prior PCI >24 hours, 14.5% with prior PCI <24 hours, and 14.1% with failed PCI (P<0.003). The in-hospital major adverse cardio-cerebral event rate was 16.4% without PCI, but 17.4% with prior PCI >24 hours, 25.6% with prior PCI <24 hours, and 41.3% with failed PCI (P=0.014). Multivariable logistic regression analysis showed prior PCI (P=0.039), as well as failed PCI (P=0.001) to be predictors for in-hospital all-cause mortality and major adverse cardio-cerebral event. Conclusions In the current PCI era, immediately prior or failed PCI before coronary artery bypass grafting in acute coronary syndromes is associated with high perioperative risk, cardiogenic shock, and increased morbidity and mortality.

Multiple percutaneous coronary interventions may negatively impact cardiac remodelling after bypass surgery

OBJECTIVES

Many patients undergo percutaneous coronary intervention (PCI) multiple times before being referred for coronary artery bypass grafting (CABG), in which bypass grafts are often anastomosed to small distal targets with higher risk of graft failure. We aimed to assess whether multiple PCIs adversely affect the long-term outcomes of patients who undergo CABG subsequently.

METHODS

A cohort of 368 patients with no history of PCI underwent initial isolated CABG between 2003 and 2013 (no PCI group). Ninety-seven patients who had undergone PCI 2 or more times preoperatively during the same period constituted the multiple PCI group. After propensity score matching, the group outcomes were compared.

RESULTS

There were no significant differences in the 10-year all-cause mortality and major adverse cardiac and cerebrovascular event rates in both groups. Although the left ventricular end-diastolic dimension in the multiple PCI group did not change markedly (from 48.0 ± 6.0 to 47.2 ± 7.9 mm; P = 0.25), it decreased significantly in the no PCI group (from 48.3 ± 6.1 to 44.9 ± 9.1 mm; P < 0.001). The left ventricular end-systolic dimension in the no PCI group decreased significantly (from 34.1 ± 8.7 to 31.4 ± 8.6 mm; P = 0.024), while it in the multiple PCI group did not (from 33.6 ± 8.3 to 32.7 ± 8.6 mm; P = 0.21).

CONCLUSIONS

For complex coronary artery disease, early surgical intervention could be considered with respect to postoperative left ventricular remodelling during the long-term follow-up.

Effect of Multiple Prior Percutaneous Coronary Interventions on Outcomes After Coronary Artery Bypass Grafting

BACKGROUND

The effect of multiple prior percutaneous coronary interventions (PCIs) before subsequent coronary artery bypass grafting (CABG) on long-term outcomes has not been well elucidated.Methods and Results:Between 2007 and 2016, 1,154 patients undergoing primary isolated CABG in our institution had no prior PCI (Group N), 225 had a single prior PCI (Group S), and 272 had multiple prior PCIs (Group M). Cumulative incidences of all-cause death, cardiac death and myocardial infarction (MI) at 10 years post-CABG were highest in Group M. After adjusting for confounders, the risk of all-cause death was higher in Group M than in Group N (hazard ratio [HR] 1.45; 95% confidence interval [CI], 1.10-1.91; P<0.01). Between Groups N and S, however, the risk of all-cause death was not different. The risks of cardiac death and MI were likewise higher in Group M than in Group N (HR, 2.39; 95% CI, 1.55-3.71; P<0.01 and HR, 3.65; 95% CI, 1.16-11.5; P=0.03, respectively), but not different between Groups N and S. The risk of repeat revascularization was not different among any of the groups.

CONCLUSIONS

Multiple prior PCIs was associated with higher risks of long-term death and cardiovascular events. The incidence of repeat revascularization after CABG was low regardless of the history of single/multiple PCIs.

Obstructive sleep apnea-induced multi-organ dysfunction after elective coronary artery bypass surgery in coronary heart disease patients

Background

The aim of this study was to explore the underlying impact of obstructive sleep apnea (OSA) on postoperative parameters of multi-organ function among coronary heart disease (CHD) patients following elective coronary artery bypass grafting (CABG).

Methods

Electronic literature databases were searched manually and automatically for relevant English articles. All of the included articles focused on a comparison of the incidence of postoperative parameters of multi-organ function in CHD patients undergoing elective CABG with and without OSA. Studies were excluded if they met any one of the following criteria: (I) duplicate publication; (II) ongoing or unpublished studies; (III) only published as abstracts or conference proceedings; and (IV) less than 30 patients in the patient cohort.

Results

A total of 13 articles met our inclusion criteria. The current study demonstrated OSA significantly increased the incidence of major adverse cardiac and cerebrovascular events (MACCEs) in CHD patients undergoing elective CABG compared with the controls [odds risk (OR), 1.97; 95% CI, 1.50 to 2.59, P<0.0001]. In addition, OSA was associated with an increased risk of new revascularization in CHD patients undergoing elective CABG (OR, 9.47; 95% CI, 2.69 to 33.33, P<0.0001). Moreover, reintubation and tracheostomy in the OSA group was increased 243% (OR, 3.43; 95% CI, 1.35 to 8.71; P=0.009) and 372% (OR, 4.72; 95% CI, 1.23 to 18.13; P=0.024), respectively, compared with the control group. Besides, we also confirmed OSA significantly increased the acute kidney injury (AKI) incidence by 124% (OR, 2.24; 95% CI, 1.07 to 4.72; P<0.0001).

Conclusions

OSA may contribute to postoperative multi-organ dysfunction among CHD patients undergoing elective CABG by increasing the incidence of MACCEs, especially new revascularization, as well as respiratory, and renal complications.

Long-term survival in patients who had CABG with or without prior coronary artery stenting

Objective

To conduct a large-scale, single-centre retrospective cohort study to understand the impact of prior percutaneous coronary intervention (PCI) on long-term survival of patients who then undergo coronary artery bypass graft (CABG).

Methods

Between 1999 and 2017, a total of 11 332 patients underwent CABG at a hospital in the UK. The patients were stratified into those who received PCI (n=1090) or no PCI (n=10 242) prior to CABG. A total of 1058 patients from each group were matched using propensity score matching. Kaplan-Meier estimates were used to assess risk-adjusted survival in patients with prior PCI. Cox proportional hazards (CoxPH) model was then used to assess the effect of prior PCI and other variables in patients undergoing CABG.

Results

The immediate postoperative outcome showed no difference in number of grafts per patients, blood transfusion, hospital stay or 30 days mortality between the groups. There was no significant difference in 5 years (90.8% vs 87.9), 10-year (76.5% vs 74.6%) and 15-year (64.4% vs 64.7%) survival between the non-PCI versus PCI groups. The Cox proportional hazards model further supports the null hypothesis as the PCI variable was found to be non-significant (CoxPH=1.03, p=0.75, CI=0.87–1.22) implying there was no difference in hazard of death for CABG patients with or without previous PCI. However, the model did yield information on the covariates that do affect the hazard of death.

Conclusion

There is no difference in 5-year, 10-year and 15-year survival between patients undergoing CABG with or without prior PCI. However, certain patient, preoperative and intraoperative risk factors were identified with high hazard of death which needs to be investigated further.

Effect of previous coronary stenting on subsequent coronary artery bypass grafting outcomes

OBJECTIVES

The effect of previous coronary stenting on subsequent coronary artery bypass graft is inconclusive.

METHODS

We used Taiwan's National Health Insurance Database to retrospectively evaluate patients with multivessel coronary artery bypass graft between January 2000 and December 2013. Overall, 32,335 patients who received coronary artery bypass graft were included, of whom 3028 had previous coronary stenting. Propensity-score matching yielded 2977 cases each for evaluation under the previous stenting and no stenting groups. The 30-day mortality and major adverse cardiac events, including all-cause mortality, acute myocardial infarction, and revascularization, were considered primary outcomes.

RESULTS

The number of coronary artery bypass grafts decreased per year. However, the percentage of patients who had previous coronary stent implantation before coronary artery bypass graft increased steadily (P for trend <.001), and the average number of stents implanted in a patient also increased per year (P for trend <.001). The previous stent group had a significantly greater 30-day mortality rate than did the no-stent group (7.2% vs 5.0%; odds ratio, 1.47; 95% confidence interval, 1.19-1.82). The previous stent group had a greater rate of revascularization (14.4% and 10.0%; subdistribution hazard ratio, 1.50; 95% confidence interval, 1.30-1.74) in the last follow-up at year 13.

CONCLUSIONS

Previous coronary stenting before coronary artery bypass graft for multivessel coronary artery disease significantly increased 30-day mortality but did not affect late survival. However, patients who had coronary stenting before coronary artery bypass graft experienced more revascularization events during late follow-up.

Risk of perioperative coronary stent stenosis or occlusion in patients with previous percutaneous coronary intervention undergoing coronary artery bypass grafting surgery

OBJECTIVES

There is an ongoing discussion about how to treat coronary stents during bypass surgery: Should patent stents be left alone and the stented vessels be ungrafted, or should every stented coronary artery receive a bypass graft? This study aims to determine the relevance of perioperative stent stenosis or occlusion on postoperative outcomes up to 3 years postoperatively.

METHODS

Patients undergoing coronary artery bypass grafting surgery (CABG) (±concomitant procedures) with previous percutaneous coronary intervention from 4 centres were prospectively included in this observatory study between April 2015 and June 2017. A coronary angiography was conducted between the fifth and seventh postoperative days. The preoperative and postoperative angiograms were assessed in a core laboratory, assessing the patencies of coronary stents and bypass grafts. The core lab investigators were blinded to the patients' characteristics and perioperative course.

RESULTS

A total of 107 patients were included in the study. In the postoperative coronary angiography, 265 bypass grafts and 189 coronary stents were examined angiographically. Ninety-seven percent of preoperatively patent stents remained patent. New coronary stent stenoses were observed in 5 patients (4.7%). All 5 patients were asymptomatic and managed conservatively. Bypass stenoses were observed in 12 patients (11%), of whom were managed conservatively, 4 underwent percutaneous coronary intervention and 1 underwent redo-CABG. Two years postoperatively, 97% of patients were alive. Patients with new stent stenosis tended to have a better survival compared with patients with bypass stenosis (100% vs 73%; P = 0.09) up to 3 years postoperatively.

CONCLUSIONS

Perioperative coronary stent stenosis occurs rarely. It is safe to leave a patently stented coronary vessel without bypass grafting.

Does Prior Percutaneous Coronary Intervention Influence the Outcomes of Coronary Artery Bypass Surgery?

Introduction

Percutaneous coronary intervention (PCI) has been increasingly performed to treat coronary artery disease. The performance of multiple PCI has also been increasing. Consequently, the percentage of patients presenting for coronary artery bypass graft (CABG) surgery is reported to vary from 13 to 40%. The influence of previous PCI on CABG outcomes has been studied in single center, regional studies, registries and meta-analyses. Some reports showed a negative effect on mortality and morbidity in early or long-term follow-up, but others did not find this influence.

Methods and Results

A cohort of 3007 patients consecutively operated for CABG, 261 of them with previous PCI, were included in this analysis. Comparison of the groups "previous PCI" and "primary CABG" was made in the original cohort and in a propensity score matched cohort of 261 patients. There were some differences in preoperative clinical characteristics in both types of cohort, even in the matched one. Outcomes were compared at 30 days, 1 year and 5 years of follow-up. There were no statistically significant differences in mortality in any period or cohort. There were some differences in other outcomes as readmission and composite events, including cardiovascular death at 1 and 5 years of follow-up. These differences, neverthless, were not confirmed in comparison with the matched cohort.

Conclusion

Although there are some limitations in this study, it was not found consistent negative influence of previous PCI on CABG.

Prior Percutaneous Coronary Interventions May Be Associated With Increased Mortality After Coronary Bypass Grafting: A Meta-Analysis

There is conflicting evidence for adverse outcomes after coronary artery bypass surgery (CABG) with prior percutaneous intervention (PCI). A literature search was performed from 1998 to 2017 and articles with primary or secondary outcomes of survival, major adverse cardiovascular events (MACE), and myocardial infarction in CABG patients with prior PCI were included. Forest plots were generated from odds ratios for survival, MACE, and myocardial infarction for unmatched and propensity-matched data. Heterogeneity between studies was assessed for all outcomes using I². Funnel plots were generated for early survival, survival at 5 years, survival at >5 years, and MACE. Thirty-one studies were included over 18 years with 194,544 patients without PCI prior to CABG and 23,519 patients (12.09%) with prior PCI. Prior PCI did not adversely affect survival among the included studies (inverse rate ratio: 1.12, 95% confidence interval: 0.98-1.27, P = 0.110. MACE was significantly worse for those with prior PCI (odds ratio: 1.26, confidence interval: 1.02-1.55, P = 0.03). The relative risk of mortality associated with prior PCI has decreased significantly over the last 2 decades. Studies with higher percentage of prior PCI patients had higher relative mortalities. There was significant heterogeneity between studies for the treatment effects. PCI prior to CABG in recent times does not adversely affect survival despite adverse early and late MACE rates. However, high institutional rates of prior PCI may be associated with increasing mortality after CABG.

Prognostic Impact of Multiple Prior Percutaneous Coronary Interventions in Patients Undergoing Coronary Artery Bypass Grafting

Background

Multiple percutaneous coronary interventions (PCIs) are considered determinant of poor outcome in patients undergoing coronary artery bypass grafting (CABG), but scarce data exist to substantiate this.

Methods and Results

Patients who underwent CABG without history of prior PCI or with PCI performed >30 days before surgery were selected for the present analysis from the prospective, multicenter E‐CABG (European Multicenter Study on Coronary Artery Bypass Grafting) registry. Out of 6563 patients with data on preoperative SYNTAX (Synergy between PCI With Taxus and Cardiac Surgery) score, 1181 patients (18.0%) had undergone PCI >30 days before CABG. Of these, 11.6% underwent a single PCI, 4.4% 2 PCIs, and 2.1% ≥3 PCIs. PCI of a single main coronary vessel was performed in 11.3%, of 2 main vessels in 4.9%, and of 3 main vessels in 1.6% of patients. Multivariable analysis showed that differences in early mortality and other outcomes were not significantly different in the study cohorts. The adjusted hospital/30‐day mortality rate was 1.8% in patients without history of prior PCI, 1.9% in those with a history of 1 PCI, 1.4% after 2 PCIs, and 2.5% after ≥3 PCIs (adjusted P=0.8). The adjusted hospital/30‐day mortality rate was 2.0% in those who had undergone PCI of 1 main coronary vessel, 1.3% after PCI of 2 main vessels, and 3.1% after PCI of 3 main coronary vessels (adjusted P=0.6).

Conclusions

Multiple prior PCIs are not associated with increased risk of early adverse events in patients undergoing isolated CABG. The present results are conditional to survival after PCI and should not be viewed as a support for a policy of multiple PCI as opposed to earlier CABG.

Clinical Trial Registration

URL: http://www.Clinicaltrials.gov. Unique identifier: NCT02319083.

See Editorial by https://doi.org/10.1161/JAHA.118.010609

The number of strata in propensity score stratification for a binary outcome

INTRODUCTION

Non-interventional and other observational studies have become important in medical research. In such observational, non-randomized studies, groups usually differ in some baseline covariates. Propensity scores are increasingly being used in the statistical analysis of these studies. Stratification, also called subclassification, based on propensity scores is one of the possible methods. There is the quasi-standard of using five strata. In this paper we focus on a binary outcome and evaluate the above-mentioned standard of using five strata.

MATERIAL AND METHODS

Bias and power for different numbers of strata are investigated with a simulation study. The methods are illustrated using data from a study where patients with diabetes mellitus and triple vessel disease undergoing coronary artery bypass surgery with and without previous percutaneous coronary intervention were compared.

RESULTS

We show that more than five strata can be more powerful and give less biased results. However, using more than ten strata hardly gives any further benefit.

CONCLUSIONS

When applying a stratification, more than five strata may be preferable, especially because of increased power. Our simulation study does not show a clear winner; hence a useful strategy could be to work with five as well as with ten strata.

Impact of prior coronary stenting on the outcome of subsequent coronary artery bypass grafting

BACKGROUND

The percentage of patients referred for coronary artery bypass grafting (CABG) who have previously undergone percutaneous coronary interventions (PCIs) is increasing. The purpose of this study was to review the outcomes of patients who had received coronary stenting before CABG, and to examine the validity of a mortality risk stratification system in this patient group.

METHODS

From 2010 to 2012, 439 patients who underwent isolated CABG at our medical center were reviewed. The patients were divided into two study groups: those who had previously received coronary artery stenting (97 patients, 24.7%), and those who had not (342 patients, 75.3%). The patients who received balloon angioplasty were excluded.

RESULTS

There were no significant differences in baseline characteristics. The prior stenting group had a lower risk of mortality, although the difference was not significant. The prior stenting group had fewer graft anastomoses (p = 0.005), and hence a significantly shorter cardiopulmonary bypass time (p = 0.045) and shorter aortic cross-clamping time. Surgical mortality was similar between the two groups. The durations of intensive care unit stay and hospitalization were also similar. The discriminatory power of the logistic European System for Cardiac Operative Risk Evaluation (EuroSCORE) was lower in both group.

CONCLUSIONS

Prior coronary stenting does not affect short-term mortality in patients subsequently undergoing CABG surgery. The EuroSCORE does not predict perioperative mortality well for the patients who undergo coronary stenting before CABG.

Repeated Target Vessel Revascularization After Coronary Artery Bypass for In-Stent Restenosis

BACKGROUND

The purpose of this study was to examine the impact of previous percutaneous coronary intervention with stent on long-term outcomes after off-pump coronary artery bypass grafting (OPCAB).

METHODS

Between January 2001 and December 2014, 1,668 patients with triple-vessel disease undergoing OPCAB were reviewed and divided into 2 groups. The no-stent group (n = 1,409) included patients who underwent OPCAB as a primary revascularization procedure and the stent group (n = 259) included patients with a history of percutaneous coronary intervention with stent. The mean follow-up duration was 5.32 ± 3.39 years.

RESULTS

After propensity score matching, characteristics of both groups were comparable (n = 259 in each group). In-hospital mortality (n = 3 [1.2%] in both groups; p > 0.999) was similar. The 14-year overall survival rate (75.6% ± 6.6% in the no-stent group versus 71.9% ± 8.5% in the stent group; p = 0.917) and freedom from major adverse cardiac and cerebrovascular events (MACCEs) rate (68.3% ± 6.6% versus 54.6% ± 8.5%; p = 0.239) were also similar. However, freedom from target vessel revascularization (TVR) rate at 14 years was significantly higher in the no-stent group (97.2% ± 1.7% versus 76.9% ± 6.5%; p < 0.001). The independent risk factor for late TVR was in-stent restenosis (hazard ratio, 3.355; 95% confidence interval, 1.925 to 5.848; p < 0.001) and it also was a risk factor for MACCEs (hazard ratio, 1.645; 95% CI, 1.105 to 2.448; p = 0.014).

CONCLUSIONS

Previous intracoronary stenting does not increase long-term mortality, but grafting to previously stented target vessels with in-stent restenosis increases the risk of repeat TVR and MACCEs.

Description of a Heart Team approach to coronary revascularization and its beneficial long-term effect on clinical events after PCI

OBJECTIVE AND BACKGROUND

We present a first description of a Heart Team (HT)-guided approach to coronary revascularization and its long-term effect on clinical events after percutaneous coronary intervention (PCI). The HT approach is a structured process to decide for coronary bypass grafting (CABG), PCI or conservative therapy in ad hoc situations as well as in HT conferences. As a hypothesis, during the long-term course after a PCI performed according to HT rules, a low number of late revascularizations, especially CABGs, are expected (F-PCI study).

METHODS

In this monocentric study, the HT approach to an all-comer population was first analyzed and described in general with the help of a database. Next the use of a HT approach was described for a more homogeneous subgroup with newly detected CAD (1.CAD). Those patients in whom the HT decision was PCI (which was a 1.PCI) were then studied with the help of questionnaires for clinical events during a very long-term follow-up. Events were CABG, PCI, diagnostic catheterization (DCath) and death.

RESULTS

A significant number of patients were presented to HT conferences: 22 % out of all 11,174 catheterizations, 24 % out of all 7867 CAD cases and 35 % out of 3408 1.CAD cases. Most of these patients had multi-vessel disease (MVD). Conference decisions were isolated CABG in 46-66 %, PCI in 10-14 %, valvular surgery in 9-16 %, HTx in 10-21 % (Endstage heart failure candidates for surgery) and conservative therapy (Medical or no therapy, additional diagnostic procedures or no adherence to recommended therapy) in 2-3 %. However, most PCIs, ad hoc and elective, were performed under Heart Team rules, but without conference. During follow-up of 1.PCI patients (Kaplan-Meier analysis), CABG occurred in only 15 % of patients, PCI in 37 % and DCath in 65 %; mortality of any course was 51 %. Mortalities were similar in one-vessel disease and in a population of the same year, matched for age and sex (p < 0.057), but mortality was higher in 1.PCI patients with MVD (p < 0.001). Beyond 2 years, Kaplan-Meier curves were linear.

CONCLUSION

The structured Heart Team approach is an effective tool for ad hoc and conference-based clinical decision-making with a sustained clinical benefit. This is demonstrated in low late CABG (and PCI) rates after a 1.PCI, without elevated mortality. The all-comer population supports the universal value of these data. Stable annual event rates late after PCI suggest a conversion to stable CAD. Heart Team conferences are also important tools in cases of valvular and end-stage heart disease.

Coronary Artery Bypass Grafting After Percutaneous Intervention Has Higher Early Mortality: A Meta-Analysis

BACKGROUND

We compared early adverse events and midterm survival between primary coronary artery bypass grafting (pCABG) and CABG in patients with percutaneous intervention (secondary CABG, sCABG) because data on this topic are very limited.

METHODS

A systematic review of published literature was done to obtain original studies fulfilling the search criteria. The end points studied were early mortality, stroke, renal failure, myocardial infarction, and the need for an intra-aortic balloon pump. A random-effect inverse variance weighted analysis was performed. The results are presented as risk ratios (RR) (95% confidence interval); p < 0.05 was considered statistically significant.

RESULTS

Fourteen studies (84,983 pCABG patients and 14,775 sCABG patients) were included in the systematic review. Early mortality was lower with primary CABG (RR 1.54 [1.19-2]; p = 0.007). The incidence of myocardial infarction was also less with pCABG than with sCABG. (RR 1.46 [1.04-2.06]; p = 0.06). Patients undergoing pCABG were 14% (0% to 55%; p = 0.04). Less likely to need an intra-aortic balloon pump. Although renal failure was lower with pCABG (RR 1.254 [1.047-1.502]; p = 0.014), the stroke rates were comparable in both cohorts (p = 0.95). Renal failure was favorable in the primary CABG cohort. Early stroke was comparable between the two cohorts (p = 0.95). The pooled hazard ratios demonstrated comparable survival at the end of 3 years (p = 0.36).

CONCLUSIONS

Patients undergoing CABG after prior percutaneous therapy have a higher incidence of myocardial infarction and mortality in the postoperative period. However, midterm survival is comparable in both cohorts.

Impact of prior intracoronary stenting on late outcomes of coronary artery bypass surgery in diabetics with triple-vessel disease

OBJECTIVE

Recent studies have indicated that coronary artery bypass grafting (CABG) outcomes in patients with prior stents are suboptimal. We aimed to study the impact of prior percutaneous coronary intervention (PCI) with stenting (PCI-S) on late CABG mortality in diabetic patients with triple-vessel disease.

METHODS

We reviewed the primary nonemergency CABG experience from a single U.S. institution (n = 7005; 1996-2007, Toledo, Ohio). Diabetics with triple-vessel disease (n = 1583) were identified and divided into 2 groups: (1) prior PCI-S (n = 202); and (2) no prior PCI (No-PCI [n = 1381]). Hierarchic Cox proportional hazards models were used to assess the effect of prior PCI-S on 5-year mortality after CABG. A propensity score for PCI-S and No-PCI patients was derived using a nonparsimonious logistic regression and used to generate a 1:1 (PCI-S to No-PCI) matched cohort.

RESULTS

In model 1, after adjusting for preoperative clinical characteristics, medications, off-pump surgery, and isolated CABG surgery status, prior PCI-S was associated with a 39% increased risk of mortality (hazard ratio [HR] = 1.39, with 95% confidence interval [CI; 1.02, 1.90]; P = .04). Further adjustment for date of surgery (model 2) (HR = 1.39, with 95% CI [1.02, 1.91]; P = .04) or operative parameters (model 3) (HR = 1.38, with 95% CI [1.01, 1.88]; P = .046) did not alter the association. The 1:1 matched-cohort analysis confirmed the increased risk associated with PCI-S (HR = 1.61, with 95% CI [1.03, 2.51]; P = .037).

CONCLUSIONS

Patients who have both diabetes and triple-vessel disease, and have undergone prior PCI-S, have poorer long-term outcomes after CABG compared with those who have had no prior PCI-S.

Does really previous stenting affect graft patency following CABG? A 5-year follow-up: The effect of PCI on graft survival

The aim of this study was to compare the graft patency rates among patients who had a previous history of percutaneous coronary intervention (PCI) followed by coronary artery bypass grafting surgery (CABG) with the patients who had experienced CABG surgery alone. The 69 patients who were included in the study had a history of bare metal stent implantation prior to CABG (group 1). The coronary angiography results were compared with 69 patients who had a previous history of CABG (group 2). Graft patency rates of the left anterior descending artery and circumflex anastomoses are statistically significant for both groups, whereas the right coronary artery anastomoses are not statistically significant (p = 0.008; 0.009; 0.2). Graft patency rate of LIMA-LAD anastomoses was 43.9 ± 10.8 % in group 1 and 86.2 ± 6 % in group 2 for means of 60 months (p = 0.0001) and circumflex coronary artery anastomosis is 28.9 ± 0.9 % in group 1, 65.7 ± 10.8 % in group 2 (p = 0.0001) and the right coronary artery anastomosis is 37.2 ± 13.6 % in group 1, 56.4 ± 8.9 % in group 2 (p = 0.0001). The graft patency rates of coronary arteries without previous stent implantation were higher than the patients with previous stent implantation and experienced CABG. The results suggest that prior PCI may induce atherosclerotic events in the vessel that can adversely affect graft patency after surgery.

Immediate Postoperative Complications in Patients Undergoing CABG; Investigating the Role of Prior Coronary Stenting

Introduction: Approximately 15 to 30% of patients undergoing percutaneous coronary intervention (PCI) will require repeated revascularization. There is an ongoing debate concerning the impact of prior PCI on subsequent coronary artery bypass graft (CABG) surgery. This study sought to compare immediate post-CABG complications between patients with and without previous coronary stenting.

Methods: A total of 556 CABG candidates including 73 patients with previous coronary stenting and 483 patients without prior stenting were enrolled in this retrospective-prospective study. Demographic information, cardiac markers (CK-MB, Troponin T), and postoperative data including inotrope administration, intra-aortic balloon pump (IABP) use, bleeding, pathological electrocardiography (ECG) changes, and overall complications were compared between the two groups.

Results: The mean age of the patients in stented group was significantly higher than that in unstented group (63.49±7.71 vs. 61.37±9.80 years, p=0.05). The mean serum level of Troponin T 12 h postoperation was significantly higher in the same group (323.26±33.16 vs. 243.30±11.52 ng/dL; p=0.03). Comparing the stented and unstented groups, the rates of inotrope use (17.8% vs. 7.2%; p=0.003), significant bleeding (15.1% vs. 4.3%; p=0.001), and overall complications (32.9% vs. 11.6%; odds ratio: 3.74 with 95% confidence interval of 2.13-6.55, p<0.001) were significantly higher in the former group. The association between overall complications and prior stenting was independent (odd ratio: 3.06). No significant connections were found between postoperative complications and stent number or type.

Conclusion: A positive history of previous coronary stenting significantly increases the risk of immediate post-CABG complications.

Continuative statin therapy after percutaneous coronary intervention improves outcome in coronary bypass surgery: a propensity score analysis of 2501 patients

OBJECTIVES

A history of percutaneous coronary intervention increases the risk of death and complications of coronary artery bypass grafting. This retrospective multicenter study evaluated the impact of continuative use of statin on postoperative outcomes when subsequent elective coronary artery bypass grafting is required after percutaneous coronary intervention.

METHODS

Among 14,575 patients who underwent isolated first-time coronary artery bypass grafting between January 2000 and December 2010, 2501 who had previous percutaneous coronary intervention with stenting and fulfilled inclusion criteria were enrolled. Continuative statin therapy was used in 1528 patients and not used in 973 patients. Logistic multiple regression and propensity score analyses were used to assess the risk-adjusted impact of statin therapy on in-hospital mortality and major adverse cardiac events. The Cox proportional hazards model was constructed to assess the effect of continuative statin therapy on 24-month outcome.

RESULTS

At multivariate analysis, age more than 70 years, 3-vessel or 2-vessel plus left main coronary disease, multivessel percutaneous coronary intervention, ejection fraction 0.40 or less, diabetes mellitus, and logistic European System for Cardiac Operative Risk Evaluation 5 or greater were independent predictors of hospital mortality and major adverse cardiac events. After propensity score matching, conditional logistic regression analysis demonstrated that continuative statin therapy before coronary artery bypass grafting reduced the risk for hospital and 2-year mortality (odds ratio [OR], 0.27; 95% confidence interval [CI], 0.12-0. 57; P=.004 and OR, 0.6; 95% CI, 0.36-0.96; P=.04, respectively) and major adverse cardiac events (OR, 0.31; 95% CI, 0.18-0.78; P=.003 and OR, 0.5; 95% CI, 0.34-0.76; P=.006, respectively).

CONCLUSIONS

Long-term statin treatment after percutaneous coronary intervention improves early and midterm outcome when surgical revascularization will be required.

CABG mortality is not influenced by prior PCI in low risk patients

BACKGROUND AND AIMS

An increasing number of patients referred for coronary artery bypass grafting (CABG) have had prior percutaneous coronary intervention (PCI). We sought to determine whether a relationship exists between increased postoperative mortality and morbidity following CABG procedure in patients with prior PCI.

METHODS

Over an 18-month period, 950 patients having first-time isolated CABG were divided into two groups based on absence (Group A, 819 patients--86.21%) or presence of a prior PCI (Group B, 131 patients--13.79%).

RESULTS

In the prior PCI population, 74 patients (56.4%) had only one stent, and only 6.8% had multiple admissions for PCI. The overall incidence of three vessel disease in the entire patient population was only 65% and the average ejection fraction was 52%. Multivariate analysis demonstrated age (OR 1.080; 95% CI: 1.020 to 1.145; p = 0.009), left ventricular ejection fraction (OR 0.939; 95% CI: 0.901 to 0.978; p = 0.002), and emergency surgery (OR 0.138; 95% CI: 0.0.045 to 0.424; p = 0.001) as risk factors for 30-day mortality, while age (OR 1.059; 95% CI: 1.016 to 1.104; p = 0.007) and emergency surgery (OR 0.205; 95% CI: 0.078 to 0.537; p = 0.001) predicted major adverse cardiac events (MACE). Prior PCI did not influence mortality or MACE at 30 days.

CONCLUSION

In this study involving low risk patients, a PCI prior to CABG did not increase morbidity or mortality.

[Correlation between previous coronary artery stenting and early mortality in patients undergoing coronary artery bypass graft surgery]

BACKGROUND

In this study, we examine the effect of previous percutaneous intervention on the rate of adverse perioperative outcome in patients undergoing coronary artery bypass graft surgery (CABG).

METHODS

Outcomes of 240 CABG patients, collected consecutively in an observational study, were compared. Gp A (n=35) had prior PCI before CABG and Gp B (n=205) underwent primary CABG.

RESULTS

Statistically significant results were obtained for the following preoperative criteria: previous myocardial infarction: 48.6% vs 36.6% (P=0.003), distribution of CAD (P=0.0001), unstable angina: 45.7% vs 39% (P=0.04). For intraoperative data, the total number of established bypasses was 2.6 (GpA) vs 2.07 (Gp B) (P=0.017), with the number of arterial bypass grafts being: 20% vs 13% (P=ns). Regarding the postoperative course, no significant difference in troponine I rate, 24-hour bleeding: 962 ml (Gp A) vs 798 ml (Gp B) (P=0.004), transfusion (PRBC unit): 3.63 (Gp A) vs 2.5 (Gp B) (P=0.006). Previous PCI emerged as an independent predictor of postoperative in-hospital mortality (OR 2.24, 95% CI [1.52-2.75], P<0.01).

CONCLUSION

Patients with prior PCI presented for CABG with more severe CAD. Thirty-day mortality and morbidity were significantly higher in patients with prior PCI.

Impact of arterial revascularization in patients undergoing coronary bypass

BACKGROUND AND AIM

A debate over alternative therapeutic strategies for multivessel coronary disease is currently ongoing. We aimed at analyzing the results of myocardial revascularization with arterial conduits.

METHODS

We retrospectively reviewed 10,752 patients undergoing isolated coronary bypass surgery within our hospital's group. Average follow-up was 37.2 months. Through propensity-matching, we generated three groups (3584 patients each) on the basis of the revascularization strategy: use of one mammary artery plus venous grafts, use of two mammary arteries plus venous graft, and total arterial revascularization.

RESULTS

Overall operative mortality was 2.8%. Patient-related factors (renal failure, advanced age, recent myocardial infarction, depressed LVEF, diabetes) were identified as predictors of mortality (logistic regression). Although mortality was not statistically different among groups, patients receiving more than one arterial conduit displayed in the long-term better freedom from cardiac death and from adverse cardiac events (repeat revascularization, myocardial infarction, recurrent angina) (Kaplan-Meier analysis). Use of only one arterial conduit, diabetes and depressed LVEF predicted cardiac mortality, and adverse events (Cox regression). No differences in any endpoint emerged among patients receiving two arterial conduit plus venous grafts or total arterial revascularization.

CONCLUSIONS

These data strongly support the practice of using two arterial conduits rather than one. The operative and late results of coronary surgery with arterial conduits are optimal and should serve as a current benchmark for the comparison with state-of-the-art percutaneous interventions.

[Modern coronary surgery, the SYNTAX trial and updated guidelines]

Coronary artery bypass grafting (CABG), a modern and safe procedure, is considered the therapy of choice in the care of patients with multi-vessel disease. The 3-year results of the SYNTAX trial not only showed surgical advantages in terms of repeat revascularisation, but the results also demonstrated significant surgical benefit for myocardial infarction and survival rates. More differentiated analyses showed distinct disadvantages in percutaneous coronary intervention (PCI) associated with the greater complexity of coronary pathology. PCI tends to be a comparable therapeutic option only in certain cases of left main stem lesions or multi-vessel disease. The findings from the SYNTAX study herald a new era in the treatment of coronary heart disease in which, as recommended in the updated guidelines issued by the EACTS/ESC in 2010, the interventionalist and the surgeon, working closely together as a"heart team", provide a sound therapy plan for affected patients.

Impact of repeated percutaneous coronary intervention on long-term survival after subsequent coronary artery bypass surgery

(Background)

In the current stent era, aggressive repeated percutaneous coronary intervention (PCI) has become more common. The aim of this study was to investigate the impact of previous repeated PCI on the subsequent coronary artery bypass grafting (CABG).

(Methods)

Between January 1990 and January 2008, a total of 894 patients underwent first-time isolated elective CABG. Among the 894 patients, 515 patients had had no PCI (group A), 179 patients had had single PCI (Group B), and 200 patients had had multiple PCI (2-15 times, mean 3.6 ± 2.3 times) (group C) before CABG. These groups were compared in terms of early and late clinical results.

(Results)

Preoperative left ventricular ejection fraction was significantly higher in group A (group A;58 ± 13%, group B;54 ± 12%, and group C;54 ± 12%). Number of bypass grafts was significantly smaller in group C (A:3.3 ± 1.0, B 3.4 ± 0.9, C 3.1 ± 1.0). Although there was no statistically significant difference among the groups, in-hospital mortality in group C was higher than that in group A and B (A:1.6%, B:1.1%, C:3.5%, p = 0.16). Survival analysis by Kaplan-Meier method (mean follow-up: 58 ± 43 methods) revealed that freedom from all-cause death and cardiac death was significantly lower in group C in comparison with group A. Freedom from cardiac event was significantly higher in group C than that in group A. Multivariate analysis identified a number of previous PCI as an independent risk factor for cardiac death.

(Conclusions)

Repeated PCI increased risk for long-term prognosis of subsequent CABG.

Coronary stenting before coronary artery bypass graft surgery in diabetic patients does not increase the perioperative risk of surgery

OBJECTIVE

A negative relationship between coronary stenting before coronary artery bypass graft (CABG) surgery and the perioperative mortality and morbidity has been shown in diabetic patients. We tried to assess this relationship in a 2-institution database.

METHODS

In the years 2005 and 2006, 1125 of 3311 patients undergoing CABG surgery had diabetes mellitus (33.9%), and 185 (16.4%) of the diabetic patients had at least 1 previous stent. There was no evidence of any clinically significant difference in the preoperative and intraoperative parameters between diabetics with or without previous stents.

RESULTS

Thirty-day mortality (no-stent group, 3.86%; stent group, 1.62%) and postoperative major adverse cardiovascular and cerebrovascular events (MACCEs; mortality, stroke, myocardial infarction, renal failure) (no-stent group, 12.2%; stent group, 5.9%) occurred more often in diabetic patients without coronary stents. Logistic regression for 30-day mortality using possible confounders including preoperative stent showed a significant positive effect of preoperative coronary stenting (OR, 0.157; 95% CI limits, 0.033-0.737). Taking percutaneous coronary intervention out of the calculation model, this positive effect was no longer significant (OR, 0.344; CI, 0.091-1.298). Logistic regression for perioperative MACCE, with as well as without percutaneous coronary intervention as a confounder, also showed a significant positive effect of preoperative coronary stenting (OR, 0.231; 95% CI, 0.091-0.590).

CONCLUSIONS

Coronary stenting before CAGB in diabetic patients does not predispose to a higher perioperative risk regarding mortality and morbidity after CABG surgery.