Mortality following operations for lower extremity peripheral arterial disease

Figures & data

Table 1 Baseline characteristics of the cohort

Variable	Total cohort (N = 230)	Patients undergoing bypass (N = 136)	Patients undergoing amputation (N = 111)
Age
Mean age (SD)	64.1 (10.1)	62.5 (9.9)	66.6 (9.9)
Age < 60 years	66 (28.7%)	44 (32.4%)	24 (21.6%)
Age 60–70 years	94 (40.9%)	60 (44.1%)	42 (37.8%)
Age 70 years and older	70 (30.4%)	32 (23.5%)	45 (40.5%)
Sex
Male	228 (99.1%)	134 (98.5%)	111 (100%)
Race/Ethnicity
African American	83 (36.1%)	41 (30.2%)	49 (44.1%)
Latino	15 (6.5%)	4 (2.9%)	12 (10.8%)
White/Other/Unknown	132 (57.4%)	91 (66.9%)	50 (45.1%)
ABI severity
Mean ABI (SD)	0.47 (0.16)	0.47 (0.14)	0.47 (0.18)
Critical≤ 0.40	66 (28.7%)	37 (27.2%)	38 (34.2%)
Moderate 0.41 to 0.69	147 (63.9%)	92 (67.7%)	63 (56.8%)
Mild 0.70–0.89	17 (7.4%)	7 (5.1%)	10 (9.0%)
Creatinine levels
None	33 (14.4%)	21 (15.4%)	14 (12.6%)
<1.0	70 (30.4%)	43 (31.6%)	36 (32.4%)
1.0–1.5	88 (38.3%)	58 (42.7%)	35 (31.5%)
1.6 or higher	39 (17.0%)	14 (10.3%)	26 (23.4%)
Atherosclerotic risk factors
Diabetes mellitus	148 (64.4%)	70 (51.5%)	88 (79.3%)
Hypertension	181 (78.7%)	102 (75.0%)	90 (81.1%)
Hyperlipidemia	141 (61.3%)	90 (66.2%)	58 (52.3%)
Recent smoking status
Current smoking	81 (35.2%)	59 (43.4%)	29 (26.1%)
Nonsmoking	14 (6.1%)	6 (4.4%)	8 (7.2 %)
Not documented	135 (58.7%)	71 (52.2%)	74 (66.7%)
Medication use
ACE inhibitor	38 (16.5%)	20 (14.7%)	19 (17.1%)
Beta blocker	20 (8.7%)	10 (7.4%)	10 (9.0%)
Calcium channel blocker	44 (19.1%)	28 (20.6%)	17 (15.3%)
Diuretic	45 (19.6%)	18 (13.2%)	29 (26.1%)
Antihypertensive medication	98 (42.6%)	50 (36.8%)	50 (45.0%)
Lipid-lowering medication	20 (8.7%)	15 (11.0%)	5 (4.5%)
Diabetes medication	59 (25.6%)	18 (13.2%)	42 (37.8%)
Smoking cessation medication	2 (0.9%)	2 (0.9%)	0 (0.0%)
PAD medication	69 (30.0%)	35 (25.7%)	37 (33.3%)

Notes:

* Patients may have undergone more than one type of limb surgery.

Abbreviations: ABI, ankle-brachial index; ACE, angiotensin converting enzyme; PAD, peripheral artery disease.

Figure 1 Model-based estimated survival curves for survival after bypass by age.

Figure 2 Model-based estimated survival curves for survival after bypass by index ABI.

Abbreviation: ABI, ankle-brachial index.

Figure 3 Model-based estimated survival curves for survival after bypass by race/ethnicity.

Table 2 Risk factors for mortality following each type of surgery

Variable	P value	Hazard ratio	95% confidence limits
Lower extremity bypass surgery
Index ABI	0.059	0.12	0.01, 1.09
Age 70 years and older	0.048	1.88	1.01, 3.51
African American race/ethnicity	0.038	1.94	1.04, 3.62
Lower extremity amputation
Index ABI	0.089	1.46	0.90, 2.35
Days between index and amputation	0.066	1.001	1.000, 1.002
Recent smoking status#
Current smoker	0.122	0.58	0.29, 1.16
Nonsmoker	0.076	0.37	0.12, 1.11
History of CAD	0.034	1.79	1.05, 3.05
Serum creatinine*
1.0 to 1.5	0.022	2.19	1.16, 4.13
1.5 to 2.0	0.038	3.84	1.94, 7.62
2.0 or greater	<0.001	4.51	2.00, 10.17
Unmeasured	0.068	2.12	0.95, 4.77

Notes:

# P-value for overall test for smoking status = 0.089, no assessment of smoking status was used as reference.

* P-value for overall test for serum creatinine effects = 0.008, unknown status used as reference.

Figure 4 Model-based estimated survival curves for survival after amputation by smoking status.

Figure 5 Model-based estimated survival curves for survival after amputation by index ABI.

Abbreviation: ABI, ankle-brachial index.

Figure 6 Model-based estimated survival curves for survival after amputation by CAD history.

Abbreviation: CAD, coronary artery disease.

Figure 7 Model-based estimated survival curves for survival after amputation by serum creatinine.