Health care administrators in New Zealand developed criteria for prioritizing certain surgical procedures during the early 1990's. One of the procedures selected was for coronary artery bypass. It was hoped that better prioritization would optimize the use of medical resources and ensure accountability in care.
Parameters used to evaluate surgical candidates:
(1) degree of coronary artery obstruction (percent diameter occluded)
(2) angina, using the Canadian Cardiovascular Society criteria after appropriate medical treatment
(3) exercise stress test findings, using the Bruce protocol
(4) ability to work, care for dependents, or live independently
|
Parameter |
Finding |
Points |
|
degree of coronary artery obstruction |
no coronary artery disease (no arterial occlusion >= 50%) |
0 |
|
|
1 vessel disease with 50-74% occlusion |
8 |
|
|
1 vessel disease at 75-89% occlusion (*) |
9 |
|
|
1 vessel disease >= 90% occlusion |
14 |
|
|
1 vessel disease >= 90% in proximal left anterior descending artery |
19 |
|
|
2 vessel disease with 50-74% occlusion (*) |
9 |
|
|
2 vessel disease at 75-89% occlusion (*) |
15 |
|
|
2 vessel disease with both >= 90% |
15 |
|
|
2 vessel disease >= 90% involving left anterior descending artery |
19 |
|
|
2 vessel disease >= 90% involving the proximal left anterior descending artery |
19 |
|
|
3 vessel disease with 50-74% occlusion (*) |
9 |
|
|
3 vessel disease >= 75% (*) |
19 |
|
|
3 vessel disease with >=90% in at least 1 vessel |
19 |
|
|
3 vessel disease with 75-89%, involving the proximal left anterior descending artery (*) |
19 |
|
|
3 vessel disease with >=90% in proximal left anterior descending artery |
27 |
|
|
left main artery 50-74% occluded (*) |
27 |
|
|
left main artery 75-89% occluded (*) |
32 |
|
|
left main artery >= 90% occluded |
36 |
|
angina |
no angina symptoms |
0 |
|
|
angina on strenuous exertion (Class I) |
1 |
|
|
angina on walking or climbing stairs rapidly (Class II) |
2 |
|
|
angina on walking 1 or 2 level blocks (Class III) |
8 |
|
|
unstable angina, pain at rest (Class IVA) |
18 |
|
|
unstable angina on oral treatment, in hospital. Symptoms improved on treatment but angina occurs with minimal provocation (Class IVB) |
22 |
|
|
unstable angina in hospital on intravenous heparin or glyceryl trinitrate (Class IVC) |
26 |
|
exercise stress test findings using the Bruce protocol |
negative |
0 |
|
|
mildly positive |
8 |
|
|
positive |
12 |
|
|
very positive |
22 |
|
ability to work, care for dependents, or live independently |
no change |
0 |
|
|
not threatened but more difficult |
1 |
|
|
threatened but not immediately |
5 |
|
|
immediately threatened |
16 |
Table 1, page 136
where:
• Some of the entries for the degree of coronary artery obstruction differ from that shown in the table, as follows
|
Text above |
Reason for Change |
|
2-3 vessel disease with 50-74% occlusion (*) |
original text "> 1 vessel disease (50-74%)" |
|
1 vessel disease at 75-89% occlusion (*) |
original text "75%"; entry matches other cells in table |
|
2 vessel disease at 75-89% occlusion (*) |
original text "50-89%", but 50-74% already scored above |
|
3 vessel disease >= 75% (*) |
degree occlusion unspecified; 50-74% already scored above |
|
3 vessel disease with 75-89% in proximal left anterior descending artery (*) |
original text "75%"; adjusted entry to match other cells in table |
|
left main artery 50-74% occluded (*) |
original text "50%"; next level was "75%" |
|
left main artery 75-89% occluded (*) |
original text "75%"; next level was ">= 90%" |
Bruce protocol:
(1) negative:
(1a) none of the findings below, or
(1b) test stopped at stage IV
(2) mildly positive: test stopped at stage III
(3) positive:
(3a) any of the criteria below but the patient not on optimal treatment, or
(3b) patient unable to progress beyond stage II for other reasons
(4) very positive:
(4a)>= 2 mm ST wave depression +/- angina in stage I; or
(4b) fall in blood pressure > 15 mm Hg in stages I or II; or
(4c) ventricular tachycardia or fibrillation in stages I or II; or
(4d) unsafe to perform test
priority score for coronary artery bypasss surgery =
= SUM(points for the 4 parameters)
Interpretation:
• minimum score: 0
• maximum score: 100
• The higher the score, the more significant the coronary artery disease.
• Scores >= 55 were associated with a considerable reduction in the quality of life. Life expectancy was reduced 1-2 years in the absence of surgery.
• Scores 35-54 were associated with a much reduced quality of life, mainly through pain on exertion. Life expectancy was reduced 8-12 months in the absence of surgery.
• Scores of 25-34 were associated with intermittent symptomatology. Life expectancy was reduced 4-8 months in the absence of surgery.
Specialty: Cardiology
ICD-10: ,
