High mortality after coronary bypass surgery in patients with high-grade left main coronary artery stenosis

Figures & data

Figure 1.  Contrast injected into the right coronary artery in a patient with complete total occlusion of the left main coronary artery. The left ventricular epicardial arteries are filled via extensive collaterals.

Table I.  Characteristics of patients undergoing coronary artery bypass in relation to degree of left main coronary artery obstruction.

		Left main stem pathology
	No stenosis (n = 3370)	Low-grade stenosis (n = 261)	High-grade stenosis (n = 224)	Complete occlusion (n = 15)
Age (years)	58±8	60±8	61±8	62±8
Body mass index (kg/m^2)	26±4	26±3	26±4	27±4
Creatinine clearance (ml/min)	83±23	83±25	80±25	78±18
No. distal anastomoses	2.9±3.7	3.6±1.1	3.4±1.2	3.1±0.7
Mammary artery graft (%)	(74)	(77)	(72)	(87)
Female gender (%)	(15)	(13)	(19)	(13)
Hypertension (%)	(26)	(26)	(28)	(40)
Hyperlipidemia (%)	(8)	(10)	(6)	(40)
Diabetes mellitus	(9)	(10)	(8)	(13)
Previous AMI (%)	(54)	(52)	(35)	(53)
Unstable angina (%)	(6)	(8)	(8)	(20)
History of stroke (%)	(3)	(7)	(5)	(0)
Peripheral vascular disease (%)	(6)	(6)	(12)	(7)
Year of surgery
1970–1979 (%)	(18)	(6)	(12)	(20)
1980–1989 (%)	(82)	(94)	(88)	(53)
No. obstructed arteries
One vessel (%)	(16%)
Two vessel (%)	(34%)	(24%)	(23%)	(33%)
Three vessel (%)	(47%)	(73%)	(69%)	(67%)
Missing (%)	(1%)	(3%)	(8%)
Left ventricular function
Normal (%)	(58)	(59)	(61)	(60)
Reduced (%)	(35)	(37)	(32)	(27)
Severely reduced (%)	(4)	(3)	(4)	(13)
Missing (%)	(3)	(1)	(3)	(0)

AMI = acute myocardial infarction.

Figure 2.  Survival in patients without stenosis, low-grade stenosis, high-grade stenosis and chronic total occlusion of the left main coronary artery. Number of remaining patients at five and ten years are indicated.

Table II.  Early, 5-year and 10-year mortality after coronary artery bypass grafting in relation to degree of left main coronary artery stenosis.

Time period	Left main coronary artery pathology
	No stenosis n = 3370	Low-grad stenosis n = 261		High-grade stenosis n = 224
≤30 days Deaths	63 deaths (1.9%)	6 deaths (2.3%)		14 deaths (6.3%)
	OR	OR	95% CI	OR	95% CI
Crude	1.0	1.2	0.5–2.9	3.5	1.9–6.4
Adjusted for age and year of surgery	1.0	1.1	0.5–2.5	2.7	1.5–5.0
Multivariate adjustment ^a	1.0	1.0	0.4–2.4	2.6	1.4–4.8
>30 days and ≤5 years Deaths	n = 3307 297 deaths (9.0%)	n = 255 25 deaths (9.8%)		n = 210 29 deaths (13.8%)
	RR	RR	95% CI	RR	95% CI
Crude	1.0	1.1	0.7–1.7	1.6	1.1–2.3
Adjusted for age	1.0	1.0	0.7–1.5	1.4	0.9–2.1
Multivariate adjustment ^b	1.0	0.9	0.7–1.2	1.4	1.1–1.8
> 30 days and ≤10 years Deaths	n = 3307 753 deaths (22.7%)	n = 255 62 deaths (24.3%)		n = 210 66 deaths (31.4%)
	RR	RR	95% CI	RR	95% CI
Crude	1.0	1.1	0.8–1.4	1.5	1.2–1.9
Adjusted for age	1.0	1.0	0.7–1.3	1.3	1.0–1.7
Multivariate adjustment ^c	1.0	1.0	0.8–1.3	1.5	1.1–1.8

^a Adjusted for age, year of surgery, previous acute myocardial infarction, number distal anastomoses and number obstructed coronary vessels.

^b Adjusted for age, previous acute myocardial infarction and number obstructed coronary vessels.

^c Adjusted for age and previous acute myocardial infarction.

OR = odds ratio; CI = confidence interval; RR = relative risk.

Table III.  Causes of late deaths during two five-year periods after coronary artery bypass grafting in relation to degree of left main coronary artery obstruction.

Time period and cause of death	Left main coronary artery pathology
> 30 days ≤ 5 years	No stenosis (n = 3307)	Low-grade stenosis (n = 255)	High-grade stenosis (n = 210)	Complete occlusion (n = 15)
Total deaths	n = 297	n = 25	n = 29	n = 1
Ischaemic heart disease (%)	185 (5.6)	18 (7.1)	18 (8.6)	1 (9)
Stroke (%)	22 (0.7)	3 (1.2)	2 (1)	0
Malignancy (%)	51 (1.5)	1 (0.4)	5 (2.4)	0
Other causes (%)	39 (1.2)	3 (1.2)	4 (1.9)	0
>5 ≤10 years	n = 3010	n = 230	n = 181	n = 14
Total deaths	n = 456	n = 37	n = 37	n = 4
Ischaemic heart disease (%)	278 (9.2)	23(10.0)	22 (12.2)	4 (29)
Stroke (%)	25 (0.8)	3 (1.3)	3 (1.7)	0
Malignancy (%)	66 (2.2)	5 (2.2)	5 (2.8)	0
Other causes (%)	87 (2.9)	6 (2.6)	7 (3.9)	0