This next series of posts designates pearls taken from Continuum education series and designed to assist preparation for vascular neurology boards. Again, many commonly understood ideas won't be blogged, only those on the fringe or confused commonly need to be blogged, so the posts may seen disjointed, but it has a purpose.
Nonmodifiable risk factors for stroke: age (doubles per decade after 55), sex (24-30% greater in men), race (2.4 fold increase for African Americans, 2 fold in Hispanics, increased in Chinese), and heredity (1.9 fold with positive family history).
Modifiable risk factors
Hypertension affects 50 million people in US, and population-attributable risk for stroke is 40 % depending on age group. In Framingham, htn > 160/95 had an age adjusted relative risk of stroke of 3.1 for men, 2.9 for women (Kannel 1970). Isolated systolic htn is also a risk factor. Dutch study showed similar. Linear relationship of stroke to bp occurs down to 115/75. JNC created a category of "prehypertension." Its defined as 120-139/80-89. These should be treated.
Atrial fibrillation
Prevalence of stroke in age>65 is 6 %. Attributable risk increases with age. In Framingham the relative risk was 20 x in patients with valvular disease + AF and 5 x in patients with AF alone. (Wolf et al 1991), which is independent of age hypertension, and other cardiac abnormalities. SPAF (Stroke in AFIB) trials clarified. SPAF studied nonvalvular afib only. SPAF I randomized to placebo, ASA or warfarin. Placebo stroke risk was 6 % per year. High risk patients were those with htn, chf, prior stroke or tia, systemic emboli, or women over 75, or LV dysfunction or increase left atrial size. SPAF III found low risk patients as defined above had stroke risk of 2 % per year on ASA and a disabling stroke risk of .8% per year. Patients with htn who were moderate risk had intermediate risk (3.6 per year). Framingham derived study based on new AF not treated with warfarin created a risk stratification model to predict 5 year risk of stroke. from JAMA 2003:
Assign points for different conditions
age <59>Points Five year risk,%
0-1 5
2-3 6
4 7
5 8
6-7 9
8 11
9 12
10 13
11 14
12 16
13 18
14 19
15 21
16 24
17 26
18 28
19 31
20 34
21 37
22 41
23 44
24 48
25 51
26 55
27 59
28 63
29 67
30 71
31 75
African Americans have less atrial fibrillation
Nonmodifiable risk factors for stroke: age (doubles per decade after 55), sex (24-30% greater in men), race (2.4 fold increase for African Americans, 2 fold in Hispanics, increased in Chinese), and heredity (1.9 fold with positive family history).
Modifiable risk factors
Hypertension affects 50 million people in US, and population-attributable risk for stroke is 40 % depending on age group. In Framingham, htn > 160/95 had an age adjusted relative risk of stroke of 3.1 for men, 2.9 for women (Kannel 1970). Isolated systolic htn is also a risk factor. Dutch study showed similar. Linear relationship of stroke to bp occurs down to 115/75. JNC created a category of "prehypertension." Its defined as 120-139/80-89. These should be treated.
Atrial fibrillation
Prevalence of stroke in age>65 is 6 %. Attributable risk increases with age. In Framingham the relative risk was 20 x in patients with valvular disease + AF and 5 x in patients with AF alone. (Wolf et al 1991), which is independent of age hypertension, and other cardiac abnormalities. SPAF (Stroke in AFIB) trials clarified. SPAF studied nonvalvular afib only. SPAF I randomized to placebo, ASA or warfarin. Placebo stroke risk was 6 % per year. High risk patients were those with htn, chf, prior stroke or tia, systemic emboli, or women over 75, or LV dysfunction or increase left atrial size. SPAF III found low risk patients as defined above had stroke risk of 2 % per year on ASA and a disabling stroke risk of .8% per year. Patients with htn who were moderate risk had intermediate risk (3.6 per year). Framingham derived study based on new AF not treated with warfarin created a risk stratification model to predict 5 year risk of stroke. from JAMA 2003:
Assign points for different conditions
age <59>Points Five year risk,%
0-1 5
2-3 6
4 7
5 8
6-7 9
8 11
9 12
10 13
11 14
12 16
13 18
14 19
15 21
16 24
17 26
18 28
19 31
20 34
21 37
22 41
23 44
24 48
25 51
26 55
27 59
28 63
29 67
30 71
31 75
African Americans have less atrial fibrillation
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