Metoprolol treatment for two years after coronary bypass grafting: effects on exercise capacity and signs of myocardial ischaemia

Medical Therapy After CABG: the Known Knowns, the Known Unknowns, and the Unknown Unknowns

PURPOSE

Medical therapies play a central role in secondary prevention after surgical revascularization. While coronary artery bypass grafting is the most definitive treatment for ischemic heart disease, progression of atherosclerotic disease in native coronary arteries and bypass grafts result in recurrent adverse ischemic events. The aim of this review is to summarize the recent evidence regarding current therapies in secondary prevention of adverse cardiovascular outcomes after CABG and review the existing recommendations as they pertain to the CABG subpopulations.

RECENT FINDINGS

There are many pharmacologic interventions recommended for secondary prevention in patients after coronary artery bypass grafting. Most of these recommendations are based on secondary outcomes from trials which include but did not focus on surgical patients as a cohort. Even those designed with CABG in mind lack the technical and demographic scope to provide universal recommendations for all CABG patients.

CONCLUSION

Recommendations for medical therapy after surgical revascularization are chiefly based on large-scale randomized controlled trials and meta-analyses. Much of what is known about medical management after surgical revascularization results from trials comparing surgical to non-surgical approaches and important characteristics of the operative patients are omitted. These omissions create a group of patients who are relatively heterogenous making solid recommendations elusive. While advances in pharmacologic therapies are clearly adding to the armamentarium of options for secondary prevention, knowing what patients benefit most from each therapeutic option remains challenging and a personalized approach is still required.

Association Between β-Blockers and Outcome of Coronary Artery Bypass Grafting: Before and After 1 Year

BACKGROUND

We evaluated the long-term outcomes of coronary artery bypass grafting (CABG) according to β-blocker therapy using landmark analysis. Although β-blockers have been shown to improve outcomes for ischemic heart disease, the long-term effects and optimal treatment duration of use after CABG remain unknown.

METHODS

From January 2001 to December 2014, 5382 CABG patients were stratified into 2 groups according to β-blocker therapy at discharge (β-blocker group: 3677 [68.3%], no β-blocker group: 1705 [31.7%]).

RESULTS

The primary outcome was all-cause death during 48 months of follow-up. Using propensity score-matched analysis, β-blocker therapy was associated with all-cause death during the 48-month follow-up (hazard ratio [HR], 0.62; 95% confidence interval [CI], 0.41-0.95; P = .03). The landmark analysis demonstrated that the effect of β-blockers on all-cause death was particularly significant within the first 12 months of therapy (HR, 0.37; 95% CI, 0.19-0.80; P = .01) but not after 12 months (HR, 0.92; 95% CI, 0.56-1.53; P = .77).

CONCLUSIONS

The benefits of postdischarge β-blockers may be limited to 1 year after CABG, but further studies are required to confirm this finding.

Do practice gaps exist in evidence-based medication prescription at hospital discharge in patients undergoing coronary artery bypass surgery & coronary angioplasty?

Background & objectives:

Prescription patterns of guideline-directed medical therapy (GDMT) after coronary artery bypass surgery [coronary artery bypass graft (CABG)] and percutaneous coronary intervention (PCI) at hospital discharge are often not optimal. In view of scarce data from the developing world, a retrospective analysis of medication advice to patients following CABG and PCI was conducted.

Methods:

Records of 5948 patients (post-PCI: 5152, post-CABG: 796) who underwent revascularization from 2010 to 2014 at a single tertiary care centre in north India were analyzed.

Results:

While age and gender distributions were similar, diabetes and stable angina were more frequent in CABG group. Prescription rates for aspirin 100 per cent versus 98.2 per cent were similar, while beta-blockers (BBs, 95.2 vs 90%), statins (98.2 vs 91.6%), angiotensin-converting enzyme inhibitors (89.4 vs 41.4%), nitrates (51.2 vs 1.1%) and calcium channel blockers (6.6 vs 1.6%) were more frequently prescribed following PCI. Despite similar baseline left ventricular ejection fraction (48.1 vs 51.1%), diuretics were prescribed almost universally post-CABG (98.2 vs 10.9%, P<0.001). Nearly all (94.4%) post-CABG patients received a prescription for clopidogrel. Patients undergoing PCI were much more likely to receive higher statin dose; 40-80 mg atorvastatin (72 vs <1%, P<0.001) and a higher dose of BB.

Interpretation & conclusions:

Significant differences in prescription of GDMT between PCI and CABG patients existed at hospital discharge. A substantial proportion of post-CABG patients did not receive BB and/or statins. These patients were also less likely to receive high-dose statin or optimal BB dose and more likely to routinely receive clopidogrel and diuretics. Such deviations from GDMT need to be rectified to improve quality of cardiac care after coronary revascularization.

Rationale for administering beta-blocker therapy to patients undergoing coronary artery bypass surgery: a systematic review

INTRODUCTION

Secondary preventative therapies are essential for patients undergoing coronary artery bypass graft (CABG) surgery to optimize perioperative and long-term outcomes. Beta-blockers are commonly used to treat patients with coronary artery disease and congestive heart failure (CHF), but their role for CABG patients remains unclear. The goal of this systematic review was to evaluate the rationale for administering beta-blockers to the CABG population and to assess their efficacy before and after coronary surgical revascularization.

AREAS COVERED

A systematic literature review was performed to retrieve relevant articles from the PubMed database published between 1985 and 2017.

EXPERT OPINION

Outside of the surgical field, strong evidence supports the use of beta-blockers for patients with a history of previous myocardial infarction (MI) or CHF. For the CABG population, studies have suggested that perioperative beta-blocker therapy is beneficial, with an associated reduction in mortality, particularly among those with a history of previous MI or CHF. Beta-blocker administration has also clearly been shown to lower the rate of new-onset postoperative atrial fibrillation after CABG. Among the different types of beta-blockers, perioperative carvedilol appears to be the most beneficial. In the absence of contraindications, nearly all CABG patients are candidates for perioperative beta-blocker therapy.

Secondary prevention after coronary artery bypass graft surgery: a primer

PURPOSE OF REVIEW

Despite the benefits of surgical coronary revascularization, patients continue to be at risk for ischemic events in the years that follow coronary artery bypass graft surgery (CABG), mandating the role for postoperative secondary preventive therapy. The purpose of this review was to present a summary on the subject of secondary prevention after CABG, including an overview of a recently published scientific statement, and highlight the newest studies in the field.

RECENT FINDINGS

Aspirin and statin therapy continue to be the mainstay of secondary prevention after CABG, although newer antiplatelet and lipid-lowering medicines are being actively studied for their potential benefits. Other important elements to secondary prevention after CABG include the aggressive management of hypertension, smoking cessation, and the initiation of cardiac rehabilitation.

SUMMARY

Secondary prevention is an essential component of postoperative care after CABG. Instituting preventive therapies after surgery optimizes graft patency and helps patients achieve the highest level of physical health and quality of life following CABG.

Efficacy of β-blocker therapy for secondary prevention for patients undergoing coronary artery bypass grafting surgery

PURPOSE OF REVIEW

The efficacy and safety of β-blockers in the treatment of cardiovascular diseases, such as ischemic heart disease, cardiac arrhythmias, and heart failure, have been well established for decades. In this article, we review the current opinions on the application of β-blockers for secondary prevention in patients undergoing coronary artery bypass grafting (CABG) surgery.

RECENT FINDINGS

As the average age of patients treated surgically for coronary artery disease (CAD) is increasing, it is not uncommon to have candidates for CABG presenting with concomitant atrial fibrillation, heart failure or hypertension, most of which were caused by excessive activation of the adrenergic nervous system. In a recent decade, a number of national quality-improvement efforts using a variety of techniques have been made to increase the use of β-blocker therapy before or following the CABG. Results from recent large observational studies among patients with CAD showed that β-blockers were associated with a lower risk of cardiac events only among those with heart failure or recent myocardial infarction. However, the consistent use of β-blockers could benefit those with or without prior myocardial infarction who underwent CABG and discharged alive.

SUMMARY

In real-world clinical practice, β-blockers are effective and safe to control heart rate and symptoms in patients with CAD, especially for those concomitant with left ventricular systolic dysfunction or prior myocardial infarction. Current evidence supports the preoperative use of β-blocker therapy for patients undergoing CABG as a prevention of new-onset atrial fibrillation. It is reasonable to continue β-blockers as chronic therapy in all CABG patients without contraindications after hospital discharge. Further strategies should be developed to understand and improve discharge prescription of β-blockers and long-term patient adherence.

β-blocker Therapy is Not Associated with Reductions in Angina or Cardiovascular Events After Coronary Artery Bypass Graft Surgery: Insights from the IMAGINE Trial

Purpose

To evaluate whether β-blockers were associated with a reduction in cardiovascular events or angina after Coronary Artery Bypass Graft (CABG) surgery, in otherwise stable low-risk patients during a mid-term follow-up.

Methods

We performed a post-hoc analysis of the IMAGINE (Ischemia Management with Accupril post–bypass Graft via Inhibition of angiotensin coNverting Enzyme) trial, which tested the effect of Quinapril in 2553 hemodynamically stable patients with left ventricular ejection fraction (LVEF) >40 %, after scheduled CABG. The association between β-blocker therapy and the incidence of cardiovascular events (death, cardiac arrest, myocardial infarction, revascularizations, angina requiring hospitalization, stroke or hospitalization for heart failure) or angina that was documented to be due to underlying ischemia was tested with Cox regression and propensity adjusted analyses.

Results

In total, 1709 patients (76.5 %) were using a β-blocker. Patients had excellent control of risk factors; with mean systolic blood pressure being 121 ± 14 mmHg, mean LDL cholesterol of 2.8 mmol/l, 59 % of patients received statins and 92 % of patients received antiplatelet therapy. During a median follow-up of 33 months, β-blocker therapy was not associated with a reduction in cardiovascular events (hazard ratio 0.97; 95 % confidence interval 0.74–1.27), documented angina (hazard ratio 0.85; 95 % confidence interval 0.61–1.19) or any of the individual components of the combined endpoint. There were no relevant interactions for demographics, comorbidities or surgical characteristics. Propensity matched and time-dependent analyses revealed similar results.

Conclusions

β-blocker therapy after CABG is not associated with reductions in angina or cardiovascular events in low-risk patients with preserved LVEF, and may not be systematically indicated in such patients.

Efficacy of Long-Term β-Blocker Therapy for Secondary Prevention of Long-Term Outcomes After Coronary Artery Bypass Grafting Surgery

Supplemental Digital Content is available in the text.

Background—

Conflicting results from recent observational studies have raised questions concerning the benefit of β-blockers for patients undergoing coronary artery bypass grafting (CABG). Furthermore, the efficacy of long-term β-blocker therapy in CABG patients after hospital discharge is uncertain.

Methods and Results—

The study included 5926 consecutive patients who underwent CABG and were discharged alive. The prevalence and consistency of β-blocker use were determined in patients with and without a history of myocardial infarction (MI). β-Blockers were always used in 1280 patients (50.9%) with and 1642 patients (48.1%) without previous MI after CABG. Compared with always users (n=2922, 49.3%), the risk of all-cause death was significantly higher among inconsistent β-blocker users (hazard ratio [HR], 1.96; 95% confidence interval [CI], 1.50–2.57), and never using β-blockers was associated with increased risk of both all-cause death (HR, 1.42; 95% CI, 1.01–2.00) and the composite of adverse cardiovascular events (HR, 1.29; 95% CI, 1.10–1.50). In the cohort without MI, the HR for all-cause death was 1.70 (95% CI, 1.17–2.48) in inconsistent users and 1.23 (95% CI, 0.76–1.99) in never users. In the MI cohort, mortality was higher for inconsistent users (HR, 2.14; 95% CI, 1.43–3.20) and for never users (HR, 1.59; 95% CI, 1.07–2.63). Consistent results were obtained in equivalent sensitivity analyses.

Conclusions—

In patients with or without previous MI undergoing CABG, the consistent use of β-blockers was associated with a lower risk of long-term mortality and adverse cardiovascular events. Strategies should be developed to understand and improve discharge prescription of β-blockers and long-term patient adherence.

Impact of statins and beta-blocker therapy on mortality after coronary artery bypass graft surgery

BACKGROUND

We conducted a retrospective cohort study of patients after first-time isolated coronary artery bypass graft surgery (CABG) and assessed the impact of a discharge regimen including beta-blockers and statin therapy and their relationship to long-term all cause mortality and major adverse cardiovascular events (MACE).

METHODS

We identified patients age >18 years, undergoing first time isolated CABG from 1993 to 2005. Patients were identified using the Cardiovascular Information Registry (CVIR). We collected follow-up information at 30, 60, 90 days and yearly follow-up. The registry is approved for use in research by the institutional review broad.

RESULTS

We identified 5,205 patients who underwent single isolated CABG between January 1993 and December 2005. The mean age was 64.5±9.7 years and over 70% were male. There was a significant difference in the low density lipoproteins (LDL) concentration between those with or without statin medications (134±41.9 mg/dL) (no statin) vs. 126±44.8 mg/dL (with statin), P=0.001. A discharge regimen with statin therapy was associated with and overall reduction in 30 day, 1 year and long-term mortality. In addition, overall the triple ischemic endpoint of death, myocardial infarction (MI) and stroke was also significantly lower in the statin vs. no-statin group. In addition, statin and beta-blockers exerted synergistic effect on overall mortality outcomes short-term and in the long-term. We note that the predictors of overall death include no therapy with statin therapy and age [hazard ratios (HR) 1.1, 95% CI: 1.04-1.078, P<0.001] and presence of renal failure (HR 2.0, P=0.005). The estimated 11-year Kaplan Meier curves for mortality between the two groups starts to diverge immediately post discharge after single isolated CABG and continue to diverge through out the follow-up period.

CONCLUSIONS

A post-discharge regimen of statins independently reduces overall and 1 year mortality. These results confirm those of earlier studies within a contemporary surgical population and support the current clinical guidelines.

Usefulness of postoperative heart rate as an independent predictor of mortality after coronary bypass grafting

Heart rate (HR) predicts mortality and cardiovascular events in the general population and in patients with coronary artery disease. However, little evidence is available for patients after coronary revascularization. The aim of this study was to assess the prognostic value of ambulatory postoperative HR after coronary artery bypass grafting. Data from a prospective cohort study enrolling patients who underwent nonurgent coronary artery bypass grafting from 1998 to 2002 were analyzed. Baseline postoperative HR was measured 2 months after surgery, and patients were followed annually thereafter. The primary outcome was all-cause mortality. The secondary outcome combined any of the following events: death, nonfatal acute coronary syndromes, stroke or transient ischemic attack, secondary coronary revascularization, or vascular surgery. Seven hundred ninety-four patients (mean age 65.8 ± 9.3 years) were eligible for follow-up, predominantly men (84.1%). The mean follow-up duration was 3.2 ± 1.3 years, during which 40 patients (5.0%) died. In the univariate analysis, HR >90 beats/min was significantly associated with all outcomes. After adjustments for major confounding factors and the use of β blockers, postoperative HR >90 beats/min remained significantly associated with the secondary outcome (hazard ratio 2.26, 95% confidence interval 1.04 to 4.91, p = 0.04). Association of postoperative HR >90 beats/min with all-cause mortality was only borderline in the multivariate analysis (hazard ratio 3.57, 95% confidence interval 0.90 to 14.17, p = 0.07), because of the limited sample population size. In conclusion, postoperative HR >90 beats/min may be associated with poor prognoses in patients with coronary artery disease, even after surgical revascularization.

Acute ischemic syndromes following coronary artery bypass graft surgery

Coronary artery bypass graft (CABG) surgery, performed for the control of angina pectoris, leads to postoperative relief from symptoms in most patients. Amelioration of ischemia and improvement in exercise capacity after CABG are well documented. However, patients currently undergoing CABG are more complex than in the past--they are older and are maintained on medical therapy for longer periods. A large number of these patients have had one or more previous myocardial revascularization procedures. The post-operative period would appear to be a time of vulnerability for coronary events. However, previous investigators have focused on the pre- and intraoperative aspects of peri-CABG ischemia. Outcome data suggest that the postoperative interval is at least equally important as a determinant of short- and long-term morbidity and mortality. We discuss the epidemiology, etiology, pathophysiology, and treatment of ischemic syndromes in the postoperative period after CABG. In addition, we review recent data from a series of 14 patients, observed at our institution, who underwent cardiac catheterization and, in some cases, angioplasty of the culprit vessel in the immediate postoperative period.

Cardiac medical therapy in patients after undergoing coronary artery bypass graft surgery

The purpose of this paper is to review the randomized controlled trial (RCT) data investigating cardiac medical therapy for patients after coronary artery bypass grafting (CABG). We identified RCTs with > or =100 enrolled patients that examined the impact of cardiac medical therapy on outcomes > or =1 year after CABG. The MEDLINE database was searched for trials conducted between 1966 and 2004 on the following medications: aspirin, antilipid agents, beta-blockers, calcium channel blockers (CCBs), nitrates, and angiotensin-converting enzyme (ACE) inhibitors. Both aspirin and antilipid agents were found to reduce the progression of atherosclerosis and the occurrence of graft occlusion. Cardiovascular events were decreased with antilipid agents. In small trials, beta-blockers and CCBs failed to decrease the incidence of cardiovascular events. No RCTs examined nitrates, and one small RCT documented a reduction in cardiovascular events among patients treated with ACE inhibitors. We conclude that few RCTs have examined the efficacy of cardiac medical therapy in post-CABG patients. Based on current RCT evidence, aspirin and antilipid agents should be used routinely after CABG. However, current data do not support the use of beta-blockers, CCBs, and nitrates, and more evidence is needed regarding the use of ACE inhibitors.

Effect of beta blockers after coronary artery bypass in postinfarct patients: what can we learn from available literature?

Studies have shown that beta adrenergic antagonist therapy benefits patients with coronary disease through reduced mortality rate after acute myocardial infarction and reduced incidence of postoperative atrial fibrillation after coronary artery bypass grafting. The long-term benefit of this therapy in survivors of myocardial infarction who are subsequently revascularized, however, has not been defined or studied rigorously. We reviewed the published data to clarify the role of beta blockade in patients who had surgical revascularization after myocardial infarction. We found that patients who received beta blockers after myocardial infarction had a reduced mortality rate and fewer cardiac events in most clinical situations, a benefit which likely extends to patients who have had subsequent surgical revascularization.