American Heart Journal
Volume 148, Issue 1 , Pages 5-6, July 2004

Coronary revascularization and quality of life

  • Mark A Hlatky, MD

      Affiliations

    • Donald W Reynolds Cardiovascular Clinical Research Center, Stanford University School of Medicine, Stanford, Calif, USA
    • Corresponding Author InformationReprint requests: Mark A. Hlatky, MD, Stanford University School of Medicine, HRP Redwood Bldg, Room 150, Stanford, CA 94305-5405, USA.

Article Outline

 

See related article on page 112.

The ultimate goal of therapy is to increase length of life, quality of life, or both in treated patients. Although the effects of cardiovascular therapies on mortality have been studied intensively, their effects on quality of life have received far less scrutiny. In particular, coronary revascularization has been examined more thoroughly for its effect on mortality and irreversible complications than for its effect on functional status and quality of life. Fortunately, more clinical trials now measure these important patient-oriented outcomes.

The sum of evidence from clinical trials of coronary bypass grafting surgery and of coronary angioplasty compared with medical therapy shows mortality rates are reduced in proportion to the extent of disease.1, 2 Bypass grafting surgery prolongs life in patients with left main disease or triple-vessel disease, especially in the setting of reduced left ventricular function.1 Angioplasty does not significantly reduce mortality rates in patients with stable coronary disease,2 but does so in patients with acute ST-segment elevation myocardial infarction.3 The effects of an aggressive approach to coronary angiography and revascularization in acute coronary syndromes has been more controversial. Although early randomized trials found no advantage to a strategy of routine angiography and aggressive coronary revascularization,4, 5 recent studies have shown an invasive approach reduces cardiac events,6, 7, 8 primarily non-fatal recurrent myocardial infarction. The invasive approach to acute coronary syndromes costs significantly more than a conservative approach,9, 10, 11 however, and the value provided by the additional invasive procedures has not been fully established.

A favorable effect on quality of life of the invasive strategy to acute coronary syndromes would provide further justification for its wider application. Coronary revascularization in patients with stable angina reduces anginal symptoms compared with medical therapy.1, 2 Objective evidence of myocardial ischemia is also reduced by coronary revascularization,12, 13 an important additional piece of evidence because therapy is unblinded in most trials and performing a procedure exerts a strong placebo effect.14, 15, 16

Quality of life is a broader concept than symptoms and includes the effect of a disease process on a patient's ability to function and enjoy life in multiple dimensions, including its physical, emotional, and social aspects. A conceptual model of patient outcomes17 suggests that symptoms of disease are the primary mediators of disease effects on health-related quality of life. Thus, in patients with coronary disease, symptoms of angina and dyspnea should be the principal determinants of health-related quality of life. Indeed, the presence and severity of angina significantly reduces various measures of quality of life.18, 19

The report from the Fragmin and/or Early Revascularization During Instability in Coronary Artery Disease (FRISC-II) trial20 provides important data on quality of life in patients randomized to undergo either an invasive or conservative approach to acute coronary syndromes. The invasive strategy resulted in better physical and emotional function on several quality of life scales that generally persisted for 12 months of follow-up. The investigators also demonstrated that the presence and severity of angina had a significant and graded adverse impact on quality of life during follow-up.20 This study extends the previous reports from FRISC-II, which showed less angina6 and exercise-induced ischemia21 in the patients who were assigned to undergo the invasive approach. This evidence of improved quality of life provides more support for the invasive approach to acute coronary syndromes.

Understanding the mechanism by which an invasive strategy improves quality of life is important in applying the FRISC-II results to clinical practice. My interpretation is that the invasive strategy led to more coronary revascularization, which reduced the frequency and severity of angina, which in turn improved the patients' quality of life. This interpretation is consistent with the conceptual model of how quality of life is affected by disease17 and is supported by the data from the Second Randomised Intervention Treatment of Angina (RITA-2) trial, which showed that the better quality of life in patients randomized to undergo coronary revascularization was completely due to differences in the prevalence of subsequent angina.19 A similar effect in FRISC-II is suggested by their finding of a strong and graded effect of angina on quality of life and the lower prevalence of angina in patients assigned to undergo the invasive strategy.20

It is important to recall that the FRISC-II study was conducted according to a protocol that permitted revascularization in the non-invasive strategy only for refractory symptoms despite maximal medical therapy.6 If revascularization had been performed as needed to control less severe angina in the non-invasive strategy, would the quality of life outcomes have been affected? It is reasonable to speculate that the significant difference in subsequent angina and quality of life found in the FRISC-II trial may be the result of this protocol-mandated high threshold for angiography and revascularization among patients assigned to undergo the non-invasive strategy. This artificial approach to symptom management is unlikely to be followed outside of a clinical trial, especially in the United States where patients and their doctors are unlikely to tolerate persistent angina. Although the FRISC-II trial results are valid within the strict design of a randomized trial, they may not necessarily be able to be generalized to routine practice. The non-invasive strategy of “watchful waiting” does not require that angina and poor quality of life be tolerated.

The FRISC-II data strongly suggest that quality of life will be enhanced by effective control of anginal symptoms. It is less certain that quality of life will be significantly improved by an early invasive approach in clinical practice. If recurrent angina is treated aggressively, quality of life should be equivalent with either an invasive or a non-invasive strategy to acute coronary syndromes.

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References 

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PII: S0002-8703(04)00124-3

doi:10.1016/j.ahj.2004.03.003

American Heart Journal
Volume 148, Issue 1 , Pages 5-6, July 2004

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