Are we negating the benefits of CABG by forgetting secondary prevention?

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.

Secondary revascularization after CABG surgery

CABG surgery is an effective way to improve symptoms and prognosis in patients with advanced coronary atherosclerotic disease. Despite multiple improvements in surgical technique and patient treatment, graft failure after CABG surgery occurs in a time-dependent fashion, particularly in the second decade after the intervention, in a substantial number of patients because of atherosclerotic progression and saphenous-vein graft (SVG) disease. Until 2010, repeat revascularization by either percutaneous coronary intervention (PCI) or surgical techniques was performed in these high-risk patients in the absence of specific recommendations in clinical practice guidelines, and within a culture of inadequate communication between cardiac surgeons and interventional cardiologists. Indeed, some of the specific technologies developed to reduce procedural risk, such as embolic protection devices for SVG interventions, are largely underused. Additionally, the implementation of secondary prevention, which reduces the need for reintervention in these patients, is still suboptimal. In this Review, graft failure after CABG surgery is examined as a clinical problem from the perspective of holistic patient management. Issues such as the substrate and epidemiology of graft failure, the choice of revascularization modality, the specific problems inherent in repeat CABG surgery and PCI, and the importance of secondary prevention are discussed.

Improved survival after coronary artery bypass grafting has not influenced the mortality disadvantage in patients with diabetes mellitus

OBJECTIVES

We sought to compare mortality after coronary artery bypass grafting in patients with and without diabetes mellitus undergoing operations during different time periods.

METHODS

We performed analyses of 12,415 primary isolated coronary artery bypass grafting operations performed during 1970-2003, with follow-up of 5-year mortality up to December 2006.

RESULTS

The prevalence of diabetes mellitus continuously increased up to 25% among patients undergoing coronary artery bypass grafting in 2003. The 1892 patients with type 2 diabetes mellitus were older, more often female, and more frequently had cardiovascular risk factors, acute coronary syndrome, 3-vessel disease, and severely reduced left ventricular function than patients without diabetes mellitus. Early mortality was 3.4% in patients with diabetes mellitus versus 1.8% in patients without diabetes mellitus. The multivariable adjusted odds ratio was 2.0, and the 95% confidence interval was 1.4 to 2.7. Early adjusted mortality was significantly lower in patients operated on during 2000-2003 than those operated on during 1970-1989 in patients with diabetes mellitus (odds ratio, 0.3; 95% confidence interval, 0.1-0.9) and without diabetes mellitus (odds ratio, 0.4; 95% confidence interval, 0.2-0.7). Mortality until 5 years was 14.6% in patients with diabetes mellitus versus 8.3% in patients without diabetes mellitus (hazard ratio, 1.8; 95% confidence interval, 1.5-2.0). Five-year mortality was reduced by 40% in patients operated on during 2000-2003 compared with that seen in those operated on during 1970-1989 in patients with and without diabetes mellitus.

CONCLUSIONS

Diabetes mellitus was associated with an almost 2-fold increased risk of early and 5-year mortality. Early and late mortality were substantially reduced in patients with and without diabetes mellitus operated on more recently, but the mortality disadvantage associated with diabetes mellitus was not eliminated.

Secondary prevention after coronary artery bypass grafting – what do we know?

There is insufficient knowledge about secondary prevention after coronary artery bypass grafting (CABG). Most of it is gathered from patients suffering from myocardial infarction and angina pectoris, only a minority of whom have undergone CABG. Whereas it seems clear that these patients should give up smoking and reduce low-density lipoprotein (LDL) cholesterol, there is uncertainty about the optimal antiplatelet regimen and antithrombotic treatment. There are some data indicating the benefit of behaviour modification. There is room for improvement and more knowledge when it comes to secondary prevention after CABG.

Patterns and predictors of statin use after coronary artery bypass graft surgery

OBJECTIVES

The benefits of statin therapy for patients with coronary artery disease have been well documented, including those occurring after coronary artery bypass graft surgery. The purposes of this study were to assess statin prescription rates in patients who have undergone coronary artery bypass graft surgery and to identify the determinants of postoperative statin administration.

METHODS

A retrospective cohort of 9284 Medicare patients aged 65 years or older who underwent coronary artery bypass graft surgery (1995-2004) was assembled by using linked hospital and pharmacy claims data. Rates of statin use after hospital discharge were calculated, and predictors of postoperative statin use were identified by using generalized estimating equations.

RESULTS

Overall, 35.9% of patients received statins within 90 days of coronary artery bypass graft surgery discharge. Use of statins within 90 days after coronary artery bypass graft surgery steadily improved during the study period, from 13.1% in 1995 to 60.9% in 2004. Patient factors independently associated with an increase in postoperative statin therapy included preoperative statin use (odds ratio, 7.69), later year of operation (odds ratio, 1.22 per additional year), and additional postoperative medications (odds ratio, 1.16 per additional medication). Factors independently associated with a decrease in postoperative statin therapy included peripheral vascular disease (odds ratio, 0.60), diabetes mellitus (odds ratio, 0.67), stroke (odds ratio, 0.77), and older age (odds ratio, 0.96 per additional year). Surgeon and hospital characteristics were not independently associated with postoperative statin use.

CONCLUSIONS

Statins are considerably underused after coronary artery bypass graft surgery, although recent prescription rates are increasing. Patterns of use do not appear to correlate with coronary artery disease risk. These findings highlight the need for targeted quality improvement initiatives to increase the rate of statin administration to this at-risk population.

Effect of risk-adjusted diabetes on mortality and morbidity after coronary artery bypass surgery

BACKGROUND

Diabetes is commonly regarded as a risk factor for mortality and morbidity after coronary artery bypass surgery.

METHODS

Between April 1997 and December 2002, 6,033 consecutive patients underwent isolated coronary artery bypass surgery. Eight hundred and fourteen (13.5%) patients had diabetes (530 oral-dependent, 284 insulin-dependent). Patients with diet-controlled diabetes were classified as nondiabetics. Deaths occurring over time were described using Kaplan-Meier techniques. To control for differences in patient characteristics, we constructed a propensity score (for diabetes) and this was included along with the comparison variable in multivariate logistic regression and Cox proportional hazards analyses.

RESULTS

In-hospital mortality was significantly higher for diabetic patients in the univariate analyses; however, this association disappeared after adjusting for the propensity score. Further analyses found that insulin-dependent diabetes was associated with an increased incidence of acute renal failure (adjusted odds ratio 4.15; p = 0.002), deep sternal wound infection (adjusted odds ratio 2.96; p = 0.039), and prolonged postoperative stay (adjusted odds ratio 1.60; p = 0.017). Oral-controlled diabetes was not associated with any of these outcomes. Four hundred and ninety-eight (8.3%) deaths occurred during the study follow-up. After adjusting for patient characteristics, the adjusted hazard ratio of midterm mortality for diabetes was 1.35; p = 0.013.

CONCLUSIONS

Insulin-dependent diabetes has a significant impact on in-hospital morbidity. Although diabetic patients are not at increased risk of in-hospital mortality, longevity is significantly decreased during a five-year follow-up period.

Clinical assessment alone will not benefit patients with coronary heart disease: failure to achieve cholesterol targets in 12,045 patients--the Healthwise II study

Healthwise II, a nurse-led audit programme in primary care during 1999-2002, assessed the uptake of secondary preventative measures for coronary heart disease (CHD). Risk factors, cardiovascular medications and blood cholesterol were recorded; 'at risk' patients were invited for a review after 6 months. Of 17,570 patients assessed, CHD was clinically present in 12,045 (69%); in these, aspirin usage was high (78%) but fewer patients were on a beta-blocker (40%), angiotensin-converting enzyme inhibitor (27%) or statin (49%). Blood pressure (BP) was controlled (<140/90) in only 41% of patients. Total cholesterol was >5 mmol/l in 49% of all CHD patients, half of whom were taking a statin. In the statin users, total cholesterol was uncontrolled (>5 mmol/l) in 38%. At follow-up, BP control remained at 42%, statin use increased to 57% and cholesterol remained elevated in 46%. Simple assessment in an audit programme fails to trigger change, and risk-factor modification for CHD remains inadequate.

Secondary Prevention of Hyperlipidemia After Coronary Artery Bypass Graft: From Acute Care to Primary Care

• Background Clinical trials have established that secondary prevention of hyperlipidemia in patients after coronary artery bypass graft (CABG) surgery prevents progression of atherosclerosis. A multidisciplinary team promotes secondary prevention by prescribing antihyperlipidemic agents, screening for risk factors, and providing education on disease, diet, and medications. Information is minimal on the number of patients who continue with antihyperlipidemic therapy or follow-up with a primary care provider for cholesterol management after antihyperlipidemic therapy is initiated in an acute surgical setting.

• Objectives To determine (1) the frequency of use of antihyperlipidemic agents before CABG surgery, at hospital discharge, and approximately 9 months after discharge and (2) the occurrence of cholesterol monitoring by a primary care provider at least once between discharge and telephone follow-up.

• Methods Observational study of 135 patients undergoing CABG surgery at a regional medical center during a 4-month period. Patients were contacted by telephone between 5 and 12 months after discharge and asked about continued use of antihyperlipidemic agents and cholesterol monitoring since discharge.

• Results Before surgery, 56% of the patients were taking an antihyperlipidemic agent. At discharge, 95% were taking an antihyperlipidemic agent. At the time of study follow-up, 91% were still taking an antihyperlipidemic agent, and 84% had follow-up cholesterol monitoring by their primary care provider.

• Conclusion Initiation of an antihyperlipidemic agent and provision of education during hospitalization for CABG surgery results in a high percentage of patients continuing antihyperlipidemic therapy and having cholesterol levels monitored by their primary care provider after discharge.