Table 1

Functional and clinical severity classifications of sample

Classification	%	Total sample (n)	%	Eligible cases (n)
Canadian Cardiovascular Society
Ineligible^1-150	65	1154	16	52
Class I	7	130	17	57
Class II	1	20	3	10
Class III	1	12	3	9
Class IV a+b	18	327	34	109
Class IVc	8	147	27	83
Total		1790		320^1-151
New York Heart Association
Ineligible^1-150	65	1154	16	52
Class I	7	130	17	57
Class II	1	20	3	10
Class III	1	12	3	9
Class IV	26	474	61	192
Total		1790		320
Parsonnet 1
Good (0–4%)	44	788	41	131
Fair (5–9%)	14	252	20	65
Poor (10–14%)	10	181	12	38
High (15–19%)	7	125	7	23
Extremely high (⩾ 20%)		444	20	63
Total	25	1790		320
Parsonnet 2
Good (0–4%)	75	1345	74	236
Fair (5–9%)	21	374	21	67
Poor (10–14%)	3	53	4	13
High (15–19%)	1	18	1	4
Extremely high (⩾ 20%)	0	0	0	0
Total		1790		320
De Bono
0–40	90	1612	62	199
40–100	10	178	38	121
Total		1790		320
New Zealand score^1-151
<25	48	39	48	39
25–35	16	13	16	13
35–55	36	30	35	30
Total		82		82^1-151

↵1-150 Patients without coded signs of angina;
↵1-151 The New Zealand score relates only to 82 patients who had no missing cardiac catheterisation data (100 had cardiac catheterisation, with 18 missing data).