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Surgical Swine Model of Chronic Cardiac Ischemia Treated by Off-Pump Coronary Artery Bypass Graft Surgery
Published on: March 27, 2018
Ten-year follow-up of survival and myocardial infarction in the randomized Coronary Artery Surgery Study
E L Alderman1, M G Bourassa, L S Cohen
1Stanford University, California.
Insights
The Coronary Artery Surgery Study found no overall survival difference between medical and surgical treatments for coronary artery disease at 10 years. However, surgery improved survival for patients with reduced ejection fraction.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Clinical Trials
Background:
- Coronary artery disease management involves medical therapy and surgical revascularization.
- The Coronary Artery Surgery Study (CASS) aimed to compare these strategies.
- Long-term outcomes and patient subgroups require further investigation.
Purpose of the Study:
- To compare the 10-year survival and morbidity outcomes of initial medical versus surgical treatment for coronary artery disease.
- To identify patient subgroups who may benefit from specific treatment strategies.
Main Methods:
- Randomized controlled trial involving 780 patients.
- Comparison of initial medical therapy versus coronary artery bypass graft surgery.
- 10-year follow-up assessing cumulative survival and freedom from nonfatal myocardial infarction.
Main Results:
- No significant difference in 10-year cumulative survival between medical (79%) and surgical (82%) groups.
- No significant difference in freedom from death and nonfatal myocardial infarction (medical 69% vs. surgical 66%).
- Patients with ejection fraction < 0.50 showed improved survival with initial surgery (61% vs. 79%, p=0.01).
- Patients with ejection fraction >= 0.50 had better freedom from events with medical therapy (75% vs. 68%, p=0.04).
Conclusions:
- Initial surgical treatment offers long-term survival benefits for patients with left ventricular dysfunction.
- For patients with mild stable angina and normal left ventricular function, initial medical therapy provides equivalent survival to initial surgery.
- Treatment strategy should consider individual patient characteristics, particularly left ventricular function.
Abstract:
The Coronary Artery Surgery Study (CASS) randomized 780 patients to an initial strategy of coronary surgery or medical therapy. Of medically randomized patients, 6% had surgery within 6 months and a total of 40% had surgery by 10 years. At 10 years, there was no difference in cumulative survival (medical, 79% vs. surgical, 82%; NS) and no difference in percentage free of death and nonfatal myocardial infarction (medical, 69% vs. surgical, 66%; NS). Patients with an ejection fraction of less than 0.50 exhibited a better survival with initial surgery treatment (medical, 61% vs. surgical, 79%; p = 0.01). Conversely, patients with an ejection fraction greater than or equal to 0.50 exhibited a higher proportion free of death and myocardial infarction with initial medical therapy (medical, 75% vs. surgical, 68%; p = 0.04) although long-term survival remained unaffected (medical, 84% vs. surgical, 83%; p = 0.75). There were no significant differences either in survival and freedom from nonfatal myocardial infarction, whether stratified on presence of heart failure, age, hypertension, or number of vessels diseased. Thus, 10-year follow-up results confirm earlier reports from CASS that patients with left ventricular dysfunction exhibit long-term benefit from an initial strategy of surgical treatment. Patients with mild stable angina and normal left ventricular function randomized to initial medical treatment (with an option for later surgery if symptoms progress) have survival equivalent to those patients randomized to initial surgery.
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