L'Italien et al used a Bayesian approach to predicting the perioperative cardiac morbidity and mortality in patients having surgery for peripheral vascular disease. The authors are from Massachusetts General Hospital in Boston.
Parameters for clinical risk score:
(1) age of patient
(2) diabetes mellitus
(3) angina pectoris
(4) congestive heart failure
(5) history of prior myocardial infarction
(6) previous coronary artery bypass procedure
|
Parameter |
Finding |
Points |
|---|---|---|
|
age of patient in years |
<= 70 years |
0 |
|
|
> 70 years |
0.5 |
|
diabetes mellitus |
absent |
0 |
|
|
present |
0.8 |
|
angina pectoris |
absent |
0 |
|
|
present |
0.8 |
|
congestive heart failure |
absent |
0 |
|
|
present |
0.6 |
|
history of prior infarction |
absent |
0 |
|
|
present |
0.5 |
|
previous coronary artery bypass procedure |
no |
0 |
|
|
yes, done <= 5 years previous |
- 2.2 |
|
|
yes, done > 5 years previous |
0 |
where:
• A coronary bypass procedure within the past 5 years was considered to have a protective effect.
clinical risk score =
= SUM(points for all 6 parameters)
Parameters for dipyridamole thallium risk score:
(1) ischemic ST wave changes
(2) fixed defect on scan
(3) reversible defect on scan
|
Parameter |
Finding |
Points |
|---|---|---|
|
ischemic ST wave changes in ECG |
absent |
0 |
|
|
present |
1.2 |
|
fixed defect |
absent |
0 |
|
|
present |
0.8 |
|
reversible defect |
absent |
0 |
|
|
present |
1.3 |
dipyridamole thallium risk score =
= SUM(points for the 3 parameters)
Calculation of estimated risk for perioperative cardiac event
(1) The initial estimated risk is looked up from Table 1 (below) based on the clinical risk score (row) and institutional complication rate (column).
(2) The final estimated risk (post-test probability) is looked up from Table 2 (below) based on the dipyridamole thallium risk score (row) and the initial estimated risk (column, from #1).
Table 1
|
|
Institutional Complication Rate |
|||||||
|---|---|---|---|---|---|---|---|---|
|
Risk Score |
2% |
4% |
6% |
8% |
10% |
12% |
14% |
16% |
|
0 to |
1% |
2% |
3% |
4% |
5% |
6% |
7% |
8% |
|
0.5 |
1% |
2% |
3% |
4% |
5% |
6% |
7% |
8% |
|
0.6 to |
1% |
3% |
4% |
6% |
7% |
9% |
11% |
12% |
|
1.0 |
2% |
3% |
5% |
7% |
8% |
10% |
12% |
13% |
|
1.1 to |
3% |
5% |
8% |
10% |
13% |
15% |
18% |
20% |
|
1.5 |
4% |
8% |
11% |
15% |
18% |
21% |
24% |
27% |
|
1.6 to |
4% |
8% |
12% |
16% |
19% |
23% |
26% |
29% |
|
2.0 |
6% |
12% |
17% |
22% |
27% |
31% |
35% |
38% |
|
2.1 to |
7% |
13% |
19% |
24% |
29% |
33% |
37% |
41% |
|
2.5 |
10% |
18% |
25% |
32% |
37% |
42% |
47% |
50% |
|
2.6 to |
11% |
20% |
27% |
34% |
40% |
45% |
49% |
53% |
|
3.0 |
15% |
27% |
36% |
43% |
50% |
55% |
59% |
63% |
where:
• The risk scores in the table is given as "> 0.5 – 1.0". Since the scores are in increments of 0.1, the next higher value after 0.5 is 0.6.
Table 2
|
|
Initial Estimated Risk |
|||||||
|---|---|---|---|---|---|---|---|---|
|
DT Score |
2.5% |
5% |
7.5% |
10% |
12.5% |
15% |
17.5% |
20% |
|
0 to |
1% |
1% |
2% |
2% |
3% |
4% |
4% |
5% |
|
0.5 |
1% |
1% |
2% |
3% |
3% |
4% |
5% |
6% |
|
0.6 to |
1% |
2% |
3% |
4% |
5% |
6% |
7% |
8% |
|
1.0 |
1% |
2% |
3% |
4% |
5% |
7% |
8% |
9% |
|
1.1 to |
2% |
3% |
5% |
7% |
8% |
10% |
12% |
14% |
|
1.5 |
2% |
5% |
7% |
10% |
12% |
15% |
17% |
20% |
|
1.6 to |
3% |
5% |
8% |
11% |
13% |
16% |
19% |
21% |
|
2.0 |
4% |
7% |
11% |
15% |
19% |
22% |
25% |
29% |
|
2.1 to |
4% |
8% |
13% |
16% |
20% |
24% |
27% |
31% |
|
2.5 |
6% |
12% |
18% |
23% |
27% |
32% |
36% |
40% |
|
2.6 to |
7% |
13% |
19% |
24% |
29% |
34% |
38% |
42% |
|
3.0 |
10% |
18% |
26% |
33% |
38% |
43% |
48% |
52% |
|
3.1 to |
12% |
21% |
30% |
37% |
43% |
48% |
53% |
57% |
|
3.5 |
14% |
24% |
34% |
42% |
48% |
53% |
58% |
62% |
Interpretation:
|
Post-Test Probability (Final Estimated Risk) |
Risk Group |
|---|---|
|
0 – 5% |
low |
|
6 – 15% |
moderate |
|
> 15% |
high |
Purpose: To use the Bayesian risk method of L'Italien et al to assess perioperative cardiac risk in a patient undergoing surgery for peripheral vascular disease.
Specialty: Cardiology, Surgery, general
Objective: risk factors, severity, prognosis, stage
ICD-10: I73,
