American Heart Journal
Volume 147, Issue 6 , Pages 948-949, June 2004

Secondary prevention after coronary artery bypass graft: a primary issue?

  • T.Bruce Ferguson Jr, MD

      Affiliations

    • Departments of Surgery and Physiology, LSUSHC, New Orleans, La, USA
    • Corresponding Author InformationReprint requests: T. Bruce Ferguson, Jr., MD, LSUSHC Cardiovascular Outcomes Research Group, 3535 Bienville Street, Suite E-325, New Orleans, LA 70119, USA.

Article Outline

 

See related article on page 1047.

For the past 35 years, cardiac surgeons have focused considerable effort on optimizing the procedure of coronary artery bypass grafting (CABG). Technical developments ranging from cardioplegic arrest to beating-heart surgery have been shown to make the operation safer.1, 2 Grafting of the left internal mammary artery to the left anterior descending coronary artery has been documented to favorably impact survival as much or more than any other procedure or therapy in cardiovascular medicine.3

During this same time period, CABG has undergone much public and scientific scrutiny, both externally and from within the specialty. These efforts to improve the technical aspects of CABG and perioperative CABG care have paid off; during the past decade, the risk-adjusted mortality from CABG surgery has declined by 23%, despite a 30% increase in predicted preoperative risk.4 However, despite this improvement in surgical mortality and morbidity outcomes, the long-term liabilities of CABG intervention remain largely unsatisfactorily addressed, namely, progression of graft and native atherosclerotic disease.

The study by Bradshaw et al5 in this issue of the Journal suggests an additional, new arena of focus for surgeons, CABG care providers, and their cardiovascular colleagues that may ultimately be as important as our surgical technical advances. This population-based analysis assessed, by survey techniques, CABG patients 6 to 20 years after surgical intervention to determine whether patients were on medications to treat their underlying cardiovascular disease and to prevent recurrent coronary events. The authors have documented that gaps exist in the use of recommended medications in this selected population, with variances related to disease and nondisease variables; these variances suggest areas for potential improvement in care quality and therefore improvement in long-term outcomes from CABG intervention. While the survey tool used in the study was somewhat limited, one can certainly agree with the authors' conclusion that more optimal management of the underlying disease following CABG is a concept worth investigating further. The study also raises 2 provocative issues: how is it best to characterize the post-CABG patient in the context of chronic ischemic heart disease, and what is the role, if any, for the surgical community to play in this longer-term effort?

This study highlights the changes in CABG patient characteristics that have occurred since 1993. Since CABG can be coupled now with newer pharmacologic therapies for heart failure and diabetes, there is an opportunity to positively impact the progression of disease and possibly increase the long-term efficacy of CABG. The Society of Thoracic Surgeons (STS) National Database has documented an increase in preoperative risk factors (hypertension, diabetes, chronic lung disease, New York Heart Association class IV, and 3-vessel disease) over the past decade on a national level analysis of over 1 million patients.4 The recent recognition that patients with coronary artery disease have a higher incidence of traditional cardiovascular risk factors6, 7 suggests that more aggressive preventive strategies will benefit a greater proportion of patients, and post-CABG patients are no exception.

During the time these patients were operated upon (1986–1993) the benefits of aspirin therapy and antilipid therapy were being investigated related to early- and mid-term graft patency;8, 9 however, little data regarding utilization were available, and consideration was not widely given to their use in long-term prevention of the underlying disease process. The American College of Cardiology/American Heart Association (ACC/AHA) guidelines current at that time focused on CABG as an isolated intervention unrelated to the chronicity of this underlying disease process except as it related to technical issues of the procedure; as such, they couldn't serve as a benchmark against which postsurgical prevention therapy could be compared. The variability in pharmacotherapy in post-CABG patients in this study supports the authors' suggestion that the 1999 CABG Guidelines10 are (again viewed retrospectively) limited in that comorbid disease processes (diabetes, hypertension) and risk factors (smoking) and their management are not more thoroughly addressed. What this study further suggests is that there should be a direct link between CABG guidelines that contain longer-term postsurgical prevention emphasis and the ACC/AHA Chronic Stable Angina guidelines11 for longer-term benchmarking of preventative strategies and outcomes. In short, CABG in this light becomes a singular intervention in a chronic, progressive disease process.

The fact that by 1999 (the year the survey was completed) over 60% of post-CABG patients were on statin therapy and over 35% of patients were on an angiotensin-converting enzyme inhibitor or angiotensin-receptor blocker is significant since neither of these pharmacologic therapies were widely available at the time of operation. While it is unlikely that surgeons had input into these therapies, the fact that these post-CABG patients were on these medications represents the positive opportunity highlighted by this study. Concomitantly, the underuse of these therapies suggests there is potential for quality improvement and emphasizes the need for increased provider collaboration to fit this operation into the chronic disease context. Unfortunately, Bradshaw's study lacks early postsurgery survey data to evaluate the initial postoperative and postdischarge management of these patients. The impact that these perioperative efforts might have had on the long-term therapy compliance and clinical outcomes is unknown. What is clear, however, is that for surgeons this represents a significant opportunity to have an impact on secondary prevention of coronary artery disease, by taking advantage of the perioperative and early postoperative period to influence both patients and providers. For example, CABG regional quality improvement efforts in Alabama,12 the Northern New England Study Group,13 and the STS nationally14 have documented that focused efforts at the time of hospitalization for CABG can improve significantly perioperative results. Strategies to increase these efforts to include secondary prevention of coronary heart disease in the long term should be explored.

The challenge for the cardiac surgical community to contribute to secondary prevention should not be underestimated. Surgeons must recognize, address, and develop methods that utilize the “teachable moment” opportunity of the 72- to 96-hour time frame of CABG hospitalization. In addition, the benchmark guidelines must focus attention on therapies and strategies beyond procedure-related issues of prevention and move toward disease process issues. Finally, process, utilization, and outcomes data need to be compared to the guideline benchmarks; this is likewise challenging, since both guidelines and preventive therapies are continually evolving.

The cardiac surgical community has, through its national and regional databases, outcomes analyses, and quality improvement efforts,14 the ability to link everyday practice and outcomes with guideline recommendations to evaluate not just the quality of delivered care but also its appropriateness. Bradshaw et al's study suggests that surgeons could be involved in not only the short-term but also in the long-term impact of CABG. As clinical cardiovascular care evolves from a primary focus on intervention to one based on the management of a chronic disease process, the concept that CABG, amortized medically and financially over time, is a highly effective palliative procedure in the context of this disease process should evolve as well. Secondary prevention following CABG is a first step in this process.

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References 

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PII: S0002-8703(04)00016-X

doi:10.1016/j.ahj.2003.12.024

American Heart Journal
Volume 147, Issue 6 , Pages 948-949, June 2004

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