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PCTA vs. CABG FAQ

PCTA vs. CABG

1.	What baseline clinical characteristics relate to short- and long-term survival after the diagnosis of coronary artery disease?
2.	What is the interaction of these baseline characteristics with treatment received and which characteristic best identifies the most efficacious treatment for an individual patient?
3.	What characteristics of coronary anatomy best define prognosis, and what is the interrelationship of treatment received and outcome as a function of extensiveness of coronary artery disease?
4.	What are the early outcomes of percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) in patients with two- and three-vessel coronary artery disease?
5.	What is the difference in the five-year survival of patients in the BARI trial treated with CABG or PTCA?
6.	Compare the time course of ischemic endpoints and the need for further medical care in BARI patients receiving PTCA or CABG?
7.	Describe differences in cost of care and quality of life in similar patients treated with CABG or PTCA?

1.	What baseline clinical characteristics relate to short- and long-term survival after the diagnosis of coronary artery disease?

Cardiac markers of short-term mortality in patients with coronary artery disease include left ventricular dysfunction, extensiveness of coronary artery disease, congestive heart failure, and acuteness of presentation. Other marker s of short-term mortality include advanced age, prior cardiac surgical procedure, and non-cardiac vascular disease and co-morbidity, especially renal or pulmonary dysfunction. Baseline characteristics that influence long-term survival, regardless of the therapy chosen, include left ventricular ejection fraction, age, co-morbidity, non-cardiac vascular disease, congestive heart failure, and myocardial infarction within 24 hours of presentation.

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2.	What is the interaction of these baseline characteristics with treatment received and which characteristic best identifies the most efficacious treatment for an individual patient?

An optimal strategy of assigning patients to the most appropriate therapy would tend to equalize the power of prognostic variables in the total population of patients, thereby negating treatment-related differences observed for individual variables. If treatment selection could be perfect, the relative power of each prognostic variable would converge on that defined only by its biologic importance. Most characteristics which identify a high risk of medical treatment in patients with coronary disease also identify patients with increased risk of either angioplasty or bypass surgery.

Coronary anatomy is the single exception to this generalization. Therefore, this baseline characteristic is most useful for identifying the most effective treatment for an individual patient. More diffuse or severe coronary atherosclerosis is associated with increased mortality in medically-treated patients, in contrast to only minimal increase in mortality risk in surgically-treated patients. Patients treated with angioplasty tend to fall between surgically- and medically-treated patients in short- and long-term outcome defined by anatomic extensiveness of disease. All other prognostic markers tend to elevate the relative risk equally in all treatment groups. Therefore, any absolute benefit conferred by either interventional treatment as a function of coronary anatomy tends to be amplified by the other markers of increased risk.

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3.	What characteristics of coronary anatomy best define prognosis, and what is the interrelationship of treatment received and outcome as a function of extensiveness of coronary artery disease?

The descriptors of coronary anatomy shown to be related to prognosis and useful for treatment selection include the number of 75% and 95% stenosis and the presence and location of a left anterior descending coronary artery (LAD). Patients with a 60% or greater stenosis of the left main coronary artery have survival benefit from surgery in comparison to medical treatment or angioplasty, and these patients should receive this treatment unless contraindications are present. Except for patients with a 95% stenosis of the proximal LAD, patients with single-vessel disease treated medically have sufficiently good prognosis that the addition of PTCA or CABG does not substantially alter their survival. Interventional therapy in these patients is commonly used for treatment of angina or pain because of acute coronary occlusion. Because long-term survival is as good or better than with CABG, patients with lesions approachable by angioplasty should receive this treatment if prevention is to be done.

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5.	What is the difference in the five-year survival of patients in the BARI trial treated with CABG or PTCA?

Five year survival in the BARI trial for 1829 randomized patients was 89.3% for CABG and 86.3% for PTCA (p=.17). However, patients subseted by those with diabetes treated with either oral agents or insulin showed a 15% survival advantage of CABG over PTCA at five years in contrast to no survival difference between assessments for those patients without diabetes. Similar trends are apparent in the smaller CABRI trial and suggest that CABG should be considered the first line of treatment in this patient group. These results raise a question of whether PTCA might also be less effective than CABG in single-vessel patients who are diabetic. Further investigation is needed to define the mechanisms underlying the better observed outcome in diabetic patients treated with CABG in comparison to angioplasty.

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6.	Compare the time course of ischemic endpoints and the need for further medical care in BARI patients receiving PTCA or CABG?

The BARI trial compared secondary endpoints related to ischemia, such as angina, anti-angina medication, ischemia on treadmill, repeat hospitalizations, and repeat revascularization procedures in the two randomized reports. Each o f these ischemia markers showed more abnormalities in patients treated with angioplasty. Both therapies were quite effective in relieving angina and decreasing ischemia on treadmill testing. However, small but significant differences in these parameters suggested CABG provided more definitive relief of myocardial ischemia than PTCA. Need for secondary procedures was most marked in the PTCA group, which required one or more secondary procedures in 70% of the PTCA population at five years in comparison to 10% of the CABG population. However, with the use of one or more additional PTCAs, only 30% of the PTCA population required CABG within five years. Therefore, for patients with an overriding goal to avoid CABG, the choice of PTCA will be 70% effective in achieving the goal with one or more PTCAs but without an additional penalty of greater risk of myocardial infarction. However, for patients who have as a primary goal the definitive relief of symptoms with little chance of requiring further intervention, CABG would be the preferred treatment.

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7.	Describe differences in cost of care and quality of life in similar patients treated with CABG or PTCA?

Extensive comparisons of markers of self-rated health quality of life assessments, physical function scores, and the time of returning to work or other productive life activities differed little between the PTCA and CABG patients in the BARI trial. Both interventional therapies were effective in improving quality of life. Comparative cost of the two treatments showed angioplasty to be less expensive initially, but as recurrent procedures were required in t he PTCA group, the cost of PTCA approached the cost of CABG by the end of five years of follow-up. At this time, CABG remained $2,000 more expensive than PTCA. However, patients with diabetes, three-vessel disease, and advanced age (markers suggesting more favorable outcomes with coronary surgery), also had a lower cost for a CABG strategy than for PTCA. PTCA was less expensive than CABG in non-diabetic, two-vessel disease and in younger patients. These results suggest that the most efficacious treatment also tended to be the most cost-effective treatment over the five-year study period.

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PCTA vs. CABG FAQ

PCTA vs. CABG

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