American Journal of Critical Care. 2004;13: 411-415
Copyright © 2004 by the American Association of Critical-Care Nurses.
Secondary Prevention of Hyperlipidemia After Coronary Artery Bypass Graft: From Acute Care to Primary Care
By
Marcia L. Brackbill, PharmD and
Christine Sytsma, RN, MSN.
From
Shenandoah University School of Pharmacy (MLB) and the Heart and Vascular Center, Winchester Medical Center (CS), Winchester, Va.
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Abstract
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• 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.
Several secondary prevention trials1,2 have indicated that cholesterol-lowering therapy with statins reduces the numbers of coronary deaths and nonfatal myocardial infarctions. Convincing research3,4 also supports the idea that initiation of treatment with a cholesterol-lowering agent after coronary artery bypass graft (CABG) surgery decreases detrimental effects of atherosclerosis in saphenous vein grafts and improves survival. A multicenter, double-blind, randomized, angiographic trial3 of treatment with lovastatin included more than 1351 patients who had undergone CABG surgery. The results indicated that aggressive lowering of serum concentrations of low-density lipoprotein (LDL) cholesterol to less than 2.59 mmol/L (100 mg/dL) was significantly more effective than moderate lowering of LDL (target 2.59–3.63 mmol/L [100–140 mg/dL]) in reducing the progression of atherosclerotic lesions in the saphenous vein graft regardless of other cardiac risk factors such as age, sex, smoking, hypertension, or diabetes.3 Grafts showed progression of atherosclerosis in 27% of patients with aggressive LDL lowering compared with 39% of patients who had only moderate LDL lowering (P < .001).3 An analysis of the Cholesterol and Recurrent Events trial also indicated a survival benefit of statin therapy in patients who had CABG surgery. In that study,4 by 5 years after the surgery, the risk of cardiovascular death or nonfatal myocardial infarction was reduced by 33% in patients treated with pravastatin compared with patients given a placebo.
Incorporating changes from various cardiovascular trials, a third update of the National Guidelines for Cholesterol Management has been published by the National Cholesterol Education Program. These guidelines support an LDL goal of less than 2.59 mmol/L (100 mg/dL) for secondary prevention of heart disease.5 Cardiac surgeons at our institution follow these guidelines when evaluating patients for antihyperlipidemic therapy immediately after surgery. Also, members of a multidisciplinary team consisting of a nurse practitioner, a case manager, staff nurses, a clinical pharmacist, and a dietician help educate the patients during the hospital stay about the importance of secondary prevention of hyperlipidemia.
| Cholesterol-lowering agents decrease atherosclerosis in saphenous vein grafts and improve survival after CABG surgery.
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Studies6–9 have indicated the number of patients being evaluated for and started on antihyperlipidemic therapy after CABG surgery. However, little information has been published on the transition between hospital management and primary care management of hyperlipidemia in the community setting. Information is minimal on the number of patients who continue taking their antihyperlipidemic medications or receive subsequent cholesterol monitoring after leaving an acute care surgical service where therapy was initiated. Belcher et al6 found that 27.9% of patients were taking a statin 1 year after CABG surgery, but these researchers did not indicate if antihyperlipidemic therapy was initiated in the acute care or primary care setting after discharge from the hospital.
The objectives of this study were to determine (1) the frequency of use of antihyperlipidemic agents before CABG surgery, at the time of discharge from the hospital, and approximately 9 months after discharge and (2) the occurrence of cholesterol monitoring by a primary care provider at least once between discharge after CABG surgery and telephone follow-up.
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Methods
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This observational study was conducted at a 400-bed regional medical center that has a comprehensive heart program with a yearly case base of more than 500 patients who undergo CABG surgery. Patients were selected during daily clinical rounds for inclusion in the study.
All patients more than 21 years old who underwent CABG surgery between September 1 and December 31, 2001, were included in the study. Patients who underwent concomitant procedures such as transmyocardial revascularization, aortic valve replacement, mitral valve replacement, carotid endarterectomy, or repair of an abdominal aortic aneurysm were also included. Patients were excluded if they had valvular surgery without CABG surgery or if they died during their hospitalization.
As per normal routine, a multidisciplinary team evaluated all patients who had CABG surgery as candidates for secondary prevention of hyperlipidemia, and education was provided after the surgery. After surgery, patients began taking their preoperative antihyperlipidemic agent again or started taking an antihyperlipidemic agent for the first time at the discretion of the cardiac surgeon and/or nurse practitioner. Most antihyperlipidemic therapy involves taking a statin. However, any prescription antihyperlipidemic agent and/or regimen initiated for purposes of secondary prevention of hyperlipidemia was recorded. In addition, baseline cholesterol levels were recorded when available.
Before discharge, each patient’s chart was reviewed by the study investigators; data were recorded on a standardized data collection form and entered into a computerized database (Access, Microsoft).
Study patients were contacted once by telephone approximately 9 months (range, 5–12 months) after discharge to evaluate the current status of antihyperlipidemic therapy, cholesterol monitoring follow-up, reduction in cardiac risk factors, and functional status. One study investigator conducted all follow-up telephone interviews to maximize reliability. Twelve health-related questions were asked during follow-up. Table 1
lists questions specific to this study.
The medical center’s quality assurance committee approved the protocol for this study.
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Results
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A total of 175 patients underwent CABG surgery during the study period. Of these patients, 163 patients met the inclusion criteria. Of these 163 patients, 135 were contacted by telephone for a follow-up interview between 5 and 12 months after their surgery. Twenty-eight people were lost to follow-up because of death or inability to contact them by telephone after at least 6 attempts on separate occasions.
The mean age of the study population was 65.6 years. Mean ages for men and women were 65.2 and 66.3 years, respectively. Table 2 gives the demographics of the study population.
The frequency of use of antihyperlipidemic agents before surgery, at discharge, and between 5 and 12 months after discharge and the frequency of cholesterol monitoring follow-up are summarized in Table 3.
Five patients who were taking an antihyperlipidemic agent at discharge were no longer taking one when asked during telephone follow-up. Reasons for discontinuation included increased liver enzyme levels (2 patients), myopathy (2 patients), and the expense (1 patient).
| Almost all patients started taking lipid-lowering agents after CABG surgery and most continued taking the agents for 9 months.
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Sixty patients were not taking an antihyperlipidemic agent before the CABG surgery. For each patient, treatment with a statin agent was initiated for secondary prevention.
Various other questions about functional status and cardiac risk factors were asked during the telephone interview. Recurrent smoking habits were also evaluated; those results are shown in Table 4.
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Discussion
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Ninety-five percent of patients were receiving an antihyperlipidemic agent at the time of discharge. This percentage is much higher than reported in other published studies,6–9 in which 14% to 47% of patients who had CABG surgery were taking antihyperlipidemic agents. Cardiac surgeons at our institution have taken an active role in evaluating all postoperative patients for secondary prevention of hyperlipidemia. If a patient is not taking an antihyperlipidemic agent before surgery, he or she is evaluated as a candidate per the latest guidelines of the National Cholesterol Education Program and starts taking an agent before discharge.
Medication compliance after discharge from the hospital and follow-up with subsequent cholesterol monitoring are of paramount importance for continued protection against progressive coronary artery disease. After an extensive search of the literature, we found only minimal information about the number of patients who continue taking an antihyperlipidemic agent after leaving an acute care cardiovascular surgical service.6 Patients typically see their cardiac surgeon during a single follow-up office appointment, provided that no postoperative complications occur. In our study, we found that 91% of patients continued taking an antihyperlipidemic agent after they left the care of the surgeon. Furthermore, 84% of our patients had visited their primary care provider for further cholesterol monitoring. Primary care providers will continue treatment for secondary prevention when such treatment is initiated by referring physicians, in this instance the cardiac surgeon. Therefore, it is crucial that patients in the surgical setting be evaluated for antihyperlipidemic therapy and that such therapy be started before they are discharged from the hospital.
The large percentage of people who were still taking an antihyperlipidemic agent at the time of our follow-up may also be due, in part, to the monitoring and education provided. Education should be viewed as an intervention. When patients are given full and easy-to-understand explanations of the importance of lowering cholesterol levels and modifying other risk factors, compliance increases. In addition, during a one-on-one session with each patient and the patient’s family, clinicians are able to assess potential reasons for the patient’s compliance or noncompliance.
A strong community referral program at the time of discharge also is an important factor in getting most patients to continue taking antihyperlipidemic agents during their transition to the primary care environment. Patients must be able to afford medications they start taking while in the hospital. Nurse case managers are acutely aware of this perceived reason for noncompliance. Before discharge, they work with lower income patients to search for alternative funding available through the community and pharmaceutical companies.
| Use of nurse case managers and consistent communication with the primary care provider enhances patients’ medication compliance.
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Central to the success of any intervention after discharge after CABG surgery is the recognition of the key role of the primary care provider. With increased specialization, the importance of this role may be overlooked. It is the primary care provider, in conjunction with the patient and the patient’s family, who is charged with follow-through on changes in lifestyle and risk-modification practices.
At our institution, the cardiac surgeon places a personal call to both the referring cardiologist and the primary care provider at the conclusion of surgery. He or she updates them on the nature of the surgery and the status of the patient. A brief operative summary is also promptly faxed to the physician’s office. Within 48 hours of a patient’s discharge, the case manager completes a synopsis of the patient’s stay, which includes any specific concerns (ie, follow-up on a high level of thyroid-stimulating hormone found during hospitalization or a newly elevated level of glycosylated hemoglobin A). Specific goals for lipid management are also noted in the comments section. A computer-generated medication record is also sent so that the physician is informed of the medications the patient is receiving at the time of discharge. It is crucial that the primary care provider be aware of lipid goals as well as medication changes in case the patient calls about some postoperative concerns.
Although not a focus of the investigation, patients were also questioned about other cardiac risk factors during the telephone follow-up. An alarming 57% of patients who smoked before CABG continued to smoke despite counseling on smoking cessation. Medication to assist with smoking cessation was prescribed for some patients. Clearly, further study on behavior modification to prevent further smoking is needed, and a stronger emphasis must be placed on smoking cessation before patients are discharged from the hospital.
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Limitations
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One limitation of this study was the patients lost to follow-up. In order to allow patients adequate time to follow up with their primary care provider, at least 5 months elapsed before we contacted our study patients. However, during this time, some patients relocated and were unavailable by telephone.
Another limitation was the method of follow-up via telephone, which lacks anonymity. Also, patients might answer questions in a positive light in order to be perceived as "compliant" patients. The questions used during the follow-up interview were not tested for reliability or validity before use. The study was done at a single medical facility with an essentially white client base, characteristics that limit the ability to apply the results to a more heterogeneous population.
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Recommendations for Further Research
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It is difficult for physicians in the acute care setting to evaluate the effectiveness of newly initiated antihyperlipidemic agents without having access to subsequent cholesterol values obtained in the primary care setting. Further research linking care in the acute care setting with care provided in the primary care setting will help practitioners evaluate the effectiveness of discharge practices in achieving desired secondary prevention outcomes.
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Conclusion
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A large percentage of patients who have CABG surgery receive an antihyperlipidemic agent for secondary prevention of hyperlipidemia when they are discharged from the hospital. Most patients who continue taking an antihyperlipidemic agent or begin taking such an agent after CABG surgery keep taking the agent and obtain follow-up cholesterol monitoring in the primary care setting.
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REFERENCES
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- Scandinavian Simvastatin Survival Study Group. Randomised trial of cholesterol lowering in 4444.patients with coronary heart disease: the Scandinavian Simvastatin Survival Study (4S). Lancet. 1994;344:1383–1389.[Medline]
- Sacks FM, Pfeffer MA, Moye LA, et al. The effect of pravastatin on coronary events after myocardial infarction in patients with average cholesterol levels. N Engl J Med. 1996;335:1001–1009.[Abstract/Free Full Text]
- The Post Coronary Artery Bypass Graft Trial Investigators. The effect of aggressive lowering of low-density lipoprotein cholesterol levels and low-dose anticoagulation on obstructive changes in saphenousvein coronary artery bypass grafts [published correction appears in N Engl J Med. 1997;337:1859]. N Engl J Med. 1997;336:153–162.[Abstract/Free Full Text]
- Flaker GC, Warnica JW, Sacks FM, et al. Pravastatin prevents clinical events in revascularized patients with average cholesterol concentrations. Cholesterol and Recurrent Events CARE Investigators. J Am Coll Cardiol. 1999;34:106–112.[Abstract/Free Full Text]
- Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults. Executive Summary of the Third Report of the National Cholesterol Education Program (NCEP) Expert Panel on Detection, Evaluation, and Treatment of High Blood Cholesterol in Adults (Adult Treatment Panel III). JAMA. 2001;285:2486–2497.[Free Full Text]
- Belcher PR, Gaw A, Cooper M, Brown M, Wheatley DJ, Lindsay GM. Are we negating the benefits of CABG by forgetting secondary prevention? J Hum Hypertens. 2002;16:691–697.[Medline]
- Khanderia U, Faulkner TV, Townsend KA, Streetman DS. Lipid-lowering therapy at hospital discharge after coronary artery bypass grafting. Am J Health Syst Pharm. 2002;59:548–551.[Free Full Text]
- Northridge DB, Shandall A, Rees A, Buchalter MB. Inadequate management of hyperlipidaemia after coronary bypass surgery shown by medical audit. Br Heart J. 1994;72:466–467.[Abstract/Free Full Text]
- Irving RJ, Oram SH, Boyd J, Rutledge P, McRae F, Bloomfield P. Ten-year audit of secondary prevention in coronary bypass patients. BMJ. 2000;321:22–23.[Free Full Text]
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Abstract
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