Clinical Indications



Fig. 5.1
The patient population with suspected CAD that is clinically most suitable for undergoing coronary CT angiography is highlighted in blue and has a pretest likelihood of disease of 20–70%. CT coronary angiography is very accurate in ruling out disease over a wide range of clinical presentations, as can be seen in the very low posttest likelihood after a negative CT (below 10% for pretest likelihoods of up to 70%). Thus, coronary CT angiography allows reliable exclusion of disease. However, patients with a likelihood of less than 20% may not benefit from noninvasive testing because of the very low positive predictive value in this group, which may lead to a rather high rate of unnecessary conventional coronary angiographies. This calculation, made according to the Bayes’ theorem, is based on the overall sensitivity and specificity of coronary CT angiography in patients with suspected CAD, as specified in Chap. 25 and modified from Schuetz et al. Ann Intern Med 2010



Thus, the preferred patient population for CT coronary angiography has a pretest likelihood of CAD of 20–70%. In Tables 5.1, 5.2, and 5.3, patients with a pretest likelihood in this range are highlighted in blue. The markings in the tables make it easy to identify those patients who are most likely to benefit from coronary CT angiography and to simultaneously exclude others who should not undergo this test. These tables may also be helpful in increasing the cost-effectiveness of coronary CT angiography, as costly and unnecessary secondary examinations, which are more likely in very low (<20%) and high-likelihood patients (>70%), can potentially increase societal costs related to the diagnosis of CAD.


Table 5.1
Likelihood (in %) of CAD according to sex, age, and symptomsa





























































Men
Women

Age (years)
Nonanginal chest painb

Atypical anginac

Typical anginad

Age (years)
Nonanginal chest painb

Atypical anginac

Typical anginad

30–39
0.8
4
26
30–39
5
22
70

40–49
3
13
55
40–49
14
46
87

50–59
8
32
79
50–59
22
59
92

60–69
19
54
91
60–69
28
67
94


a The range of patients who are most likely to benefit from coronary CT angiography is highlighted in blue (those with a likelihood of 20–70%). In the 30–69-year age range, all men with atypical symptoms would be expected to benefit from CT, whereas women with atypical angina pectoris would be suitable candidates for coronary CT angiography only if they were older than 50 years of age. Modified from Diamond and Forrester New Engl J Med 1979

b Only one of the three characteristics of angina pectoris is present (either retrosternal localization of pain, pain precipitated by exercise or decreased at rest, or on nitrate medication)

c Only two of the three characteristics of angina pectoris are present

d All of the three characteristics of angina pectoris are present



Table 5.2
Posttest likelihood (in %) of CAD in women after an electrocardiographic stress test (ST depression), according to age and symptomsa




























































































































































































Women

ST depression (mm)
Age (years)
Asymptomatic
Nonanginal chest painb

Atypical anginac

Typical anginad

0–0.5
30–39
0.1
0.2
1
7
 
40–49
0.2
0.7
3
22
 
50–59
0.8
2
10
47
 
60–69
2
5
21
69

0.5–1.0
30–39
0.3
0.7
4
24
 
40–49
0.9
3
12
53
 
50–59
3
8
31
78
 
60–69
7
17
52
90

1.0–1.5
30–39
0.6
2
9
42
 
40–49
2
6
25
72
 
50–59
7
16
50
89
 
60–69
15
33
72
95

1.5–2.0
30–39
1
3
16
59
 
40–49
4
11
39
84
 
50–59
12
28
67
94
 
60–69
25
49
83
98

2–2.5
30–39
3
8
33
79
 
40–49
10
24
63
93
 
50–59
27
50
84
98
 
60–69
47
72
93
99.1

>2.5
30–39
11
24
63
93
 
40–49
28
53
86
98
 
50–59
56
78
95
99.3
 
60–69
76
90
98
99.7


a The range of women who are most likely to benefit from coronary CT angiography is highlighted in blue (20–70%). Modified from Diamond and Forrester New Engl J Med 1979

b Only one of the three characteristics of angina pectoris is present (either retrosternal localization of pain, pain precipitated by exercise or decreased at rest, or on nitrate medication)

c Only two of the three characteristics of angina pectoris are present

d All of the three characteristics of angina pectoris are present

Please note that 1.0 mm is equal to 0.1 mV



Table 5.3
Posttest likelihood (in %) of CAD in men after an electrocardiographic stress test (ST depression), according to age and symptomsa
































































































































































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Mar 14, 2016 | Posted by in CARDIOVASCULAR IMAGING | Comments Off on Clinical Indications

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Men

ST depression (mm)
Age (years)
Asymptomatic
Nonanginal chest painb

Atypical anginac

Typical anginad

0–0.5
30–39
0.4
1
6
25
 
40–49
1
4
16
61
 
50–59
2
6
25
73
 
60–69
3
8
32
79

0.5–1.0
30–39
2
5
21
68
 
40–49
5
13
44
86
 
50–59
9
20
57
91
 
60–69
11
26
65
94

1.0–1.5
30–39
4
1
38
83
 
40–49
11
26
64
94
 
50–59
19
37
75
96
 
60–69
23
45
81
97

1.5–2.0
30–39
8
19
55
91
 
40–49
20
41
78
97
 
50–59
31
53
86
98
 
60–69
37
62
90
99

2.0–2.5
30–39
18
38
76
96
 
40–49
39
65
91
99
 
50–59
54
75
94
99.2
 
60–69
61
81
96
99.5