1. COMPARISONS OF BYPASS SURGERY WITH MEDICAL THERAPY
Trial Cooperative
Patients
Randomized
VA cooperative trial (VA)
686
1972-74
European cooperative surgical
study (ECSS)
768
1973-76
Coronary artery surgery study
(CASS)
780
1974-79
Survival
2. Severity of angina
Objective evidence of ischemia
Instability of angina (crossover 20% 6 months, 50% 5 years)
Myocardial infarction
Severity of stenosis (L. main, 3 vessel, proximal LAD)
Left ventricular dysfunction
Age
3. SUMMARY
Patients with single, double or triple vessel disease, good ventricular function
(>50%) and no exercise induced ischemia have a good prognosis.
Improved survival is seen in patients with triple vessel disease, left main disease and
reduced ejection fraction (>35%, <50%) following surgery.
Improved surgical survival is seen in patients with any two of the following clinical
risk factors: h/o hypertension, h/o myocardial infarction, resting ST- T abnormalities.
4. COMPARISON OF BYPASS SURGERY WITH ANGIOPLASTY
The randomized interventional treatment of angina (RITA) - March 1993, Lancet (longest
follow-up)
The German Angioplasty Bypass Surgery Investigation (GABI) 1994 - New England Journal
The Coronary Artery Bypass Revascularization Investigation (CABRI) August 1993
Argentine Randomized trial of Percutaneous Transluminal Coronary Angioplasty v/s
coronary artery bypass surgery (ERACI) October 1993, JACC.
5. RITA TRIAL
CABG
PTCA
Inclusion Criteria
Symptomatic or asymptomatic SVD or MVD;
suitable for equivalent revascularization
Baseline Characteristics Class 3-4
angina 59%; hx MI 43%;
3VD 12% > 3Rx 38%
Patients (n)
501
510
Early outcome
------------------In-hospital-------------------
Death
1.2%
0.8%
MI
2.4%
3.5%
Reintervention
------
6.7%
Late outcome
------------------2-2.5 years------------------
Death
3.6%
3.1%
MI
5.2%
6.7%
CABG
0.8%
18.8%
PTCA
3.2%
18.2%
Event-free survival
89%
62%
Symptom-free
78%
69%
6. GABI TRIAL
CABG
PTCA
Inclusion Criteria
Symptomatic MVD; suitable for complete revascularization
Baseline Characteristics Class
4 angina, 19%; hx MI 50%; mean LVEF 56%
Patients (n)
177
182
Early outcome
------------------In-hospital-------------------
Death
2.2%
1.1%
MI
8.0%
2.7%
Reintervention
NR
NR
Late outcome
---------------------1 year---------------------
Death
2.8%
1.6%
MI
8.0%
3.8%
CABG
1.1%
23.0%
PTCA
4.5%
27.0%
Event-free survival
94%
58%
Symptom-free
80%
80%
7. CABRI TRIAL
CABG
PTCA
Inclusion Criteria
Symptomatic or asymptomatic MVD; LVEF > 35%
Baseline Characteristics
Class 3-4
angina 66%; hx MI 42%; 3VD 40% > 3Rx 26%,
mean LVEF 63%
Patients (n)
513
541
Early outcome
---------------------30 day--------------------
Death
0.9%
1.7%
MI
2.9%
3.1%
Reintervention
1.6%
10.1%
Late outcome
--------------------1 year ---------------------
Death
2.1%
3.9%
MI
3.3%
2.9%
CABG
1.4%
20.2%
PTCA
7.2%
20.1%
Event-free survival
85%
60%
Symptom-free
91%
85%
8. ERACI TRIAL
CABG
PTCA
Inclusion Criteria
Symptomatic MVD; suitable for revascularization
Baseline Characteristics
Class 3-4 angina; LVEF > 35%
Patients (n)
64
63
Early outcome
------------------In-hospital-------------------
Death
4.6%
1.5%
MI
6.2%
6.3%
Reintervention
NR
NR
Late outcome
---------------------1 year---------------------
Death
0%
3.2%
MI
.8%
3.2%
CABG
0%
18.0%
PTCA
3.2%
14%
Event-free survival
83.5%
63.7%
Symptom-free
90%
65%
9. Survival (older 3v disease, + 2v disease, - 1v disease)
Symptom free survival
Incidence of myocardial infarction
Freedom from crossover to CABG after angioplasty (5 yrs - 25%)
Event free survival
10. For low risk patients with two vessel disease, angioplasty may provide modest
survival benefits relative to medical therapy.
In single vessel disease, the primary treatment choice is between medicine and PTCA
Survival benefits of surgical revascularization are magnified on the absolute scale by
factors that increase overall medical risk, especially left ventricular dysfunction and
advanced age. These factors tend to increase procedural risks but offer proportionately
greater long-term benefits than can be expected with medical treatment
11. Summary
The more extensive the coronary artery disease, the larger the benefit derived from
surgical revascularization
In the most severe forms of coronary artery disease (Left main, triple vessel) bypass
surgery provides the best long term survival results
In patients with two vessel disease, the higher the risk the more likely that patient will
have improved survival with bypass surgery (eg. impaired left ventricular function, older
age, co-existing vascular disease)
EXTENDED OUTLINE
Surgical Indications for Coronary Revascularization
I. Objectives of CABG
- relieve ischemia
- prolong survival
- prevent MI..
- preserve LV function
- improve exercise tolerance
II. Assessing CABG Candidates
- degree of symptoms
- associated medical problems
- evidence of reversible ischemia
- Documentation of abnormal coronaries
- LV function
III. Angina
A. Chronic Stable Angina defined as stable pain pattern for 4-6 weeks
B. Canadian Cardiovascular Society Classification
Class I. Angina: occurs with strenuous activity
Class II. Angina: pain with rapid walk or climbing multiple stairs
Class III Angina: pain with walking < 2 blocks on level ground @ a normal
pace or climbing one flight of stairs
Class IV. : pain with minimal activity or @ rest if it last < 15 min.
Unstable Angina: pain @ rest that last more than 15 min.
IV. Studies
A. General
1. three major studies of medical vs. surgical treatment
2. use of early CABG techniques
3. no LIMA
4. no wide spread use of cardioplegia
5. no postop antiplatelet therapy
B. VA Study (1970)
1. 686 patients
2. criteria
3. results:
a. 36 month survival was 87% in the medical group and 88% in the surgical
arm
b. 7 year survival 70% with medical and 77% with surgical
d. beyond 7 years any survival advantage with surgery begins to disappear
except in patients with three vessel disease and decreased LV function
C. European Cooperative Surgical Study (ECSS)
1. 768 men, < 65 yrs old, > 3 month hx of angina, @ least 2 vessel
disease, and LV function > 50%
2. results:
a. survival @ 16 months was 93.5% in the surgical group and 84.1% in the
medical group
b. survival advantage was greatest in patients with three vessel disease,
left main disease , or two vessel disease with a proximal LAD lesion
3. Conclusion:
- symptomatic stable angina with left main , three vessel, or two vessel
disease including a proximal LAD lesion benefit from surgery
D. Coronary Artery Surgery Study (CASS)
1. 2099 patients, 780 truly randomized the other chose their therapy
2. set out to answer the question which was the best therapy for patients with
minimal symptoms - most patients had class I and II angina
3. results:
a. survival @ 5 yrs was equal in medical and surgical groups
b. medical group had a 5%/ yr. conversion to surgery
c. increased survival @ 7 yrs for patients with decreased EF and three vessel
disease
4. Conclusion:
a. mild angina with an EF between 35 - 50%, and three vessel disease had
increased survival @ seven years
b. incidence of MI was the same in both groups
V. Indications for CABG
1. failure of medical therapy
2. unstable angina
3. Left main disease
4. symptomatic three vessel disease
5. post infarction angina
6. acute MI with shock
7. failed PTCA
8. reoperation for recurrent symptoms
9. congenital anomalies
10. Kawasaki's disease
A. Failure of medical therapy
B. Unstable Angina
- surgery provides increased relief of symptoms, but no survival benefit
compared to medical therapy
C. Left main
D. 3 Vessel disease and decreased LV function
E. Post-infarction Angina
F. Acute MI with Shock
G. Failed PTCA
H. Reop with recurrent symptoms
- factors associated with decreased reop survival
-
Survival
5 yr.
10 yr.
first
surgery
90%
75%
reop
80%
60% |
