Lipid Lowering in "Very High Risk" Patients Undergoing Coronary Artery Bypass Surgery and Its Projected Reduction in Risk for Recurrent Vascular Events: A Monte Carlo Stepwise Simulation Approach.

ABSTRACT: 2018 AHA guidelines provide criteria to identify patients at very high risk (VHR) for adverse vascular events and recommend an low density lipoprotein-C (LDL-C) level <1.8 mmol/L. Data regarding the 10-year risk for adverse vascular events in coronary artery bypass grafting (CABG) patients at VHR and the need for nonstatin therapies in the VHR cohort are limited. We queried a national cohort of CABG patients to answer these questions. The projected reduction of LDL-C from stepwise escalation of lipid-lowering therapy (LLT) was simulated; Monte Carlo methods were used to account for patient-level heterogeneity in treatment effects. Data on preoperative statin therapy and LDL-C levels were obtained. In the first scenario, all eligible patients not at target LDL-C received high-intensity statins, followed by ezetimibe and then alirocumab; alternatively, bempedoic acid was also used. The 10-year risk for an adverse vascular event was estimated using a validated risk score. Potential risk reduction was estimated after simulating maximal LLT. Before CABG, 8948 of 27,443 patients (median LDL-C 85 mg/dL) were at VHR. In the whole cohort, 31% were receiving high-intensity statins. With stepwise LLT escalation, the proportion of patients at target were 60%, 78%, 86%, and 97% after high-intensity statins, ezetimibe, bempedoic acid, and alirocumab, respectively. The projected 10-year risk to suffer a vascular event reduced by 4.6%. A large proportion of CABG patients who are at VHR for vascular events fail to meet 2018 AHA LDL-C targets. A stepwise approach, particularly with the use of bempedoic acid, can significantly reduce the need for more expensive proprotein convertase subtilisin kexin 9 inhibitors.

Outcomes of coronary artery bypass grafting in patients with heart failure with a midrange ejection fraction.

BACKGROUND: Coronary artery bypass grafting (CABG) improves survival in patients with heart failure and severely reduced left ventricular systolic function (LVEF). Limited data exist regarding adverse cardiovascular event rates after CABG in patients with heart failure with midrange ejection fraction (HFmrEF; LVEF > 40% and < 55%). METHODS: We analyzed data on isolated CABG patients from the Veterans Affairs national database (2010-2019). We stratified patients into control (normal LVEF and no heart failure), HFmrEF, and heart failure with reduced LVEF (HFrEF) groups. We compared all-cause mortality and heart failure hospitalization rates between groups with a Cox model and recurrent events analysis, respectively. RESULTS: In 6533 veterans, HFmrEF and HFrEF was present in 1715 (26.3%) and 566 (8.6%) respectively; the control group had 4252 (65.1%) patients. HFrEF patients were more likely to have diabetes mellitus (59%), insulin therapy (36%), and previous myocardial infarction (31%). Anemia was more prevalent in patients with HFrEF (49%) as was a lower serum albumin (mean, 3.6 mg/dL). Compared with the control group, a higher risk of death was observed in the HFmrEF (hazard ratio [HR], 1.3 [1.2-1.5)] and HFrEF (HR, 1.5 [1.2-1.7]) groups. HFmrEF patients had the higher risk of myocardial infarction (subdistribution HR, 1.2 [1-1.6]; P = .04). Risk of heart failure hospitalization was higher in patients with HFmrEF (HR, 4.1 [3.5-4.7]) and patients with HFrEF (HR, 7.2 [6.2-8.5]). CONCLUSIONS: Heart failure with midrange ejection fraction negatively affects survival after CABG. These patients also experience higher rates myocardial infarction and heart failure hospitalization.

Off-Pump Coronary Artery Bypass Grafting: Department of Veteran Affairs' Use and Outcomes.

Background Coronary artery bypass can be performed off pump (OPCAB) without cardiopulmonary bypass. However, trends over time for OPCAB versus on-pump (ONCAB) use and long-term outcome has not been reported, nor has their long-term outcome been compared. Methods and Results We queried the national Veterans Affairs database (2005-2019) to identify isolated coronary artery bypass procedures. Procedures were classified as OPCAB on ONCAB using the as-treated basis. Trend analyses were performed to evaluate longitudinal changes in the preference for OPCAB. The median follow-up period was 6.6 (3.5-10) years. An inverse probability weighted Cox model was used to compare all-cause mortality between OPCAB and ONCAB. From 47 685 patients, 6759 (age 64±8 years) received OPCAB (14%). OPCAB usage declined from 16% (2005-2009) to 8% (2015-2019). Patients with triple vessel disease who received OPCAB received a lower mean number of grafts (2.8±0.8 versus 3.2±0.8; P<0.01). The ONCAB 5-, 10-, and 15-year survival rates were 82.9% (82.5-83.3), 60.4% (59.8-61.1), and 37.2% (36.1-38.4); correspondingly, OPCAB rates were 80.7% (79.7-81.7), 57.4% (56-58.7), and 34.1% (31.7-36.6) (P<0.01). OPCAB was associated with increased risk-adjusted all-cause mortality (hazard ratio, 1.15 [1.13-1.18]; P<0.01) and myocardial infarction (incident rate ratio, 1.16 [1.05-1.28]; P<0.01). Conclusions Over 15 years, OPCAB use declined considerably in Veterans Affairs medical centers. In Veterans Affairs hospitals, late all-cause mortality and myocardial infarction rates were higher in the OPCAB cohort.

Adverse events after coronary artery bypass grafting in patients with preoperative metabolic syndrome: A 10-year follow-up of the Veterans Affairs Database.

INTRODUCTION: Data regarding 10-year survival and adverse cardiovascular events in patients with metabolic syndrome (MET) after coronary artery bypass grafting (CABG) is limited. METHODS: We compared 10-year events rates for veterans undergoing isolated CABG (January 1, 2005, to December 31, 2014, follow-up October 31, 2019) stratified by presence of metabolic syndrome (MET+) versus without (MET-). A multivariable weighted Cox model was used to analyze all-cause mortality. Competing risk analysis was used to calculate cumulative event rates for congestive heart failure, myocardial infarction, and cerebrovascular events. The Fine-Gray subhazard model was used to determine adjusted association of MET with myocardial infarction and stroke. Congestive heart failure was modeled as a recurrent-event analysis. RESULTS: Nationally, 9615 adults (median age, 60 years; 98.9% men) underwent isolated coronary artery bypass grafting at 41 centers); among them, 3121 out of 9615 (32.5%) had MET. The prevalence of MET increased from (27.88% in 2005 to 34.02% in 2014; P = .02). MET+ group members were likely younger (median age, 63 vs 64 years; P < .01), White (72% vs 68%), and had more peripheral vascular disease (30% vs 28%; P = .04). Multivessel (72% vs 70%; P = .23) and multiarterial (4% vs 4%; P = .14) grafting was performed equally. With a median follow-up of 6.5 years, survival was similar (P = .26); however, MET was associated with higher risks for myocardial infarction (21% vs 16%; hazard ratio, 1.3; P < .01) and recurrent admissions for congestive heart failure. CONCLUSIONS: Patients with metabolic syndrome undergoing coronary artery bypass grafting have higher 10-year cardiovascular event rates.

Revascularization in ischaemic heart failure with preserved ejection fraction: a nationwide cohort study.

AIMS: Despite the common occurrence of coronary artery disease (CAD) and heart failure (HF) with preserved ejection fraction (HFpEF), there is limited evidence to guide revascularization. METHODS AND RESULTS: We investigated the long-term outcomes of coronary artery bypass grafting (CABG) in patients with HF and significant CAD across the spectrum of ejection fraction, using a large national cohort of patients from the Veteran Affairs (VA) Medical Centers in the US. Patients with HF were stratified into groups, HFpEF, HF with mid-range ejection fraction (HFmrEF), and HF with reduced ejection fraction (HFrEF) and compared to patients with no preoperative HF. We analysed 10 396 patients. Despite an increased hazard in the first year following revascularization, the long-term survival (median follow-up 6.6 years; interquartile range 3.7-10.1) of HFpEF post-CABG was similar to controls (hazard ratio 0.85, 95% confidence interval 0.68-1.06), but survival progressively declined with HFmrEF and HFrEF. Similar trends were seen with recurrent HF hospitalization with lower risk with baseline HFpEF (43.9 ± 6.9/100 patient-years) compared to HFmrEF (65.9 ± 3.8/100 patient-years) and HFrEF (93.4 ± 4.8/100 patient-years). Although HFpEF patients had lower mortality and HF hospitalization post-CABG compared to patients with a lower ejection fraction, they experienced the highest rates of future myocardial infarction. CONCLUSION: Although HFpEF patients with CAD have greater short-term risk post-CABG, their long-term survival is comparable to controls. However, they are at increased risk for HF hospitalizations and myocardial infarction. These data support the safety of CABG in HFpEF patients and suggest continuum of mortality risk for ischaemic HF when stratified by baseline ejection fraction before revascularization.

Emerging trends in mediastinitis: National Veterans Health Administration experience with methicillin-resistant Staphylococcus aureus prevention.

OBJECTIVES: Perioperative bacterial decolonization and prophylactic antibiotic therapy at the Veterans Affairs Health Care System have changed over the past decade. Our objectives were to identify associated changes in the microbiology of mediastinitis and to perform a contemporary survival analysis in patients with mediastinitis after isolated coronary artery bypass grafting procedure. METHODS: From January 2006 to December 2015, 45,323 consecutive patients underwent coronary artery bypass grafting at 83 medical centers. The Veterans Affairs Health Care System nationwide administrative database was queried to identify patients with postoperative mediastinitis and obtain patient-level data. Simple descriptive statistics and multivariable logistic regression were used to analyze microbiologic data and identify risk factors for infection. Poisson regression was used to determine yearly incidence estimates. Cox proportional hazard model identified predictors of long-term survival from date of operation. RESULTS: During the study period, 348 patients (0.78%) developed postoperative mediastinitis-with a stable rate of incidence (Cochrane-Armitage test, P = .69). Of patients with microbiologic data, 75.5% of infections (n = 188) were caused by gram-positive and 24.5% (n = 61) gram-negative organisms. The incidence of methicillin-resistant Staphylococcus aureus mediastinitis decreased during the study period (Cochrane-Armitage test, P = .013). Gram-negative mediastinitis occurred earlier than gram-positive mediastinitis (median, 15.0 vs 25.0 days; P < .0001). Patients with mediastinitis did not have increased 30-day mortality (2.0% vs 1.9%; P = .9), but had worse long-term survival compared with uninfected patients (P < .0001). CONCLUSIONS: The incidence of methicillin-resistant S aureus mediastinitis has decreased over the past decade. Gram-negative bacteria are responsible for 1 in 4 cases of mediastinitis and infection is diagnosed earlier in the postoperative period than gram-positive mediastinitis. These findings highlight the need for efforts to prevent gram-negative and methicillin-susceptible S aureus mediastinitis.

Pre-operative glycaemic control and long-term survival in diabetic patients after coronary artery bypass grafting.

OBJECTIVES: We analysed the Veteran Affairs data to evaluate the association of pre-operative glycated haemoglobin (HbA1c) and long-term outcome after isolated coronary artery bypass grafting (CABG). METHODS: Veterans with diabetes mellitus and isolated CABG (2006-2018) were divided into 4 groups (I: HbA1c <6.5%, II: HbA1c 6.5-8, III 8-10% and IV: HbA1c >10%). The relationship of pre-operative HbA1c and long-term survival was evaluated with a multivariable Cox proportional hazards model and reported as hazard ratios (HR). The cumulative incidence of secondary end-points [myocardial infarction (MI) and repeat revascularization (percutaneous intervention)] for each group was modelled as competing events with cause-specific Cox proportional hazards models. RESULTS: Overall, 16 190 patients (mean age 64.9 years, male 98%; insulin dependent 53%) with diabetes mellitus underwent isolated CABG. We observed 19.4%, 45.4%, 27% and 8.2% patients in groups I, II, III and IV, respectively. Patients with HbA1c >10% were the youngest (mean age 60.9 years) and had high rates of Insulin dependence (78%). In patients with HbA1c >10%, improvement in levels was observed in 76%. The median follow-up observed was 5.8 (3.2-8.8) years. Compared to the study mean HbA1c (7.3%), mortality rate increased with HbA1c levels >8%, and especially with pre-operative HbA1c levels >9%. Compared to patients with HbA1c <8%, HbA1c 8-10% and >10% were associated with increased MI (HR 1.24 and HR 1.39, respectively) and need for reintervention (HR 1.20 and HR 1.24, respectively). CONCLUSIONS: In patients undergoing CABG, pre-operative HbA1c >8% is associated with the increased risk of mortality and adverse cardiac events.