ISCHEMIC STROKE / PREVENTION

Vascular risk factors

Created 26/03/2021, last revision 22/12/2022

Vascular risk factors
Non-modifiable risk factors
(cannot be changed)
  • previous stroke
  • person’s age
    • older people have a higher risk of developing cardiovascular disease. A healthy lifestyle is recommended to help reduce the risk
  • race
    • people of South Asian, African, or Caribbean descent have a higher risk of developing cardiovascular disease
  • male sex
  • family history

    • having a first-degree relative who developed CVD at a relatively young age (father/brother developed CVD before the age of 55, or mother/sister developed CVD before the age of 65)
    • a family history of high blood pressure, high cholesterol, and type 2 diabetes may also increase the likelihood of developing these conditions, which in turn may increase the risk of CVD
Modifiable risk factors
(can be reduced or controlled with altered behavior)
  • hypertension
  • dyslipidemia (high levels of fats in the blood, such as cholesterol and triglycerides)
  • diabetes
  • heart disease
    • atrial flutter and fibrillation
    • thrombus in the left atrium or ventricle
    • valvular defects
    • spontaneous echo contrast
    • atherosclerotic plaques and thrombi in the ascending aorta
  • cerebrovascular occlusive disease
  • smoking
  • hematologic disorders
  • overweight/obesity
  • lack of exercise
  • hyperhomocysteinemia
  • stress
  • drug abuse
  • alcoholism
  • hormonal contraception
  • migraine
  • inflammatory markers
    • C-reactive protein (CRP)
    • erythrocyte sedimentation rate (ESR)
    • fibrinogen, ferritin, and some other acute-phase proteins
  • sleep disorders (sleep apnea syndrome – SAS)

.

Vascular risk factors

↓

Subclinical damage
endothelial dysfunction, enlarged IMT, increased arterial stiffness, myocardial hypertrophy, vascular hypertrophy, microalbuminuria

↓

Manifest cardiovascular diseases (CVD)
stroke/TIA, coronary artery disease (CAD), peripheral artery disease (PAD), aneurysm

Progression of atherosclerosis

Cardiovascular risk

The overall cardiovascular risk depends on:

  • risk factors control → ASCVD Risk Estimator Plus
    • a value of > 5% is considered as high risk (probability of death from cardiovascular disease in the next 10 years > 5%)
  • subclinical damage of target organs
  • clinical manifestation of CVD
    • people with overt CVD or renal disease have a high (> 5%) or very high (> 10%) risk of vascular death in the next 10 years
    • type 1 diabetes (T1D) with microalbuminuria and type 2 diabetes (T2D) have a high cardiovascular risk (> 5%)

Ankle-brachial pressure index (ABPI)

  • the Ankle-Brachial Pressure Index (ABPI) is a quick, non-invasive way to check peripheral artery disease (PAD)
    • the disease occurs when narrowed arteries reduce the blood flow to the limbs
    • an abnormal ABPI may be an independent predictor of mortality, as it reflects the burden of atherosclerosis
  • it is a ratio of the blood pressure at the ankle to the blood pressure in the upper arm (brachial BP)
    • the patient must be in the supine position, without the head or any extremities dangling over the edge of the table
    • the brachial BP is measured in both arms, and the higher value is used
  • a low ABPI index indicates narrowing or occlusion of peripheral arteries in the legs

   ankle BP

ABPI = ———————————

brachial BP

Interpretation of ABPI
> 1.3 abnormal  (vessel hardening due to calcifications)
1-1.2 normal
0.9-0.99
 acceptable
0.8-0.89 mild PAD
 0.8 – 0.5 moderate PAD
< 0.5 severe PAD

Intima-media thickness (IMT)

  • the standard measurement is performed in B-mode on the far wall of the CCA, 10 mm proximal to the bifurcation
    • use high-resolution images
    • optimize the insonation angle (90° to the vessel wall)
  • measure the distance between the 2 echogenic lines
    • the 1st line is the lumen-intima interface
    • the 2nd line is the media-adventitia interface
  • obtain at least five measurements on each side and get an average value (“average IMT”); specialized software may be helpful  Automated IMT measurement (GE LOGIQ) [Baldassare, 2000]
  • avoid atherosclerotic plaques when measuring IMT (lesions > 1.5 mm are already considered plaque)
  • echogenicity, especially of the media, may be increased in the presence of fatty infiltration and thickening
  • IMT > 95th. percentile for age and sex is considered abnormal (usually IMT >1 mm is abnormal)
Carotid intima-media thickness (CIMT)
Intima-media thickness (IMT) on ultrasound imaging
Female (95. percentile)
 Male (95. percentile)
45 y
 55 y
 65 y
 45 y 55 y
 65 y
0.73
 0.91 1.04
0.89
 1 1.3

95.th percentile  [Howard, 1993]

Age
 P25 P50
 P75
Men <30 0.39 0.43 0.48
Men 31-40  0.42 0.46 0.50
Men 41-50 0.46 0.50 0.57
Men >50  0.46 0.52 0.62
Women <30 0.39 0.40 0.43
Women 31-40 0.42 0.45 0.49
Women 41-50 0.44 0.48 0.53
Women >50 0.50 0.54 0.59

Prognostic value of IMT measurement

  • not only atherosclerotic plaques but also IMT can quantify atherosclerosis burden in asymptomatic patients
  • IMT should be assessed in each extracranial ultrasound examination
    • increased IMT is the first stage of atherosclerosis and, if left untreated, is followed by plaque formation
    • clinical and epidemiological studies have shown an association between IMT and coronary artery disease (CAD), stroke, and peripheral vascular disease (PAD) (ROTTERDAM, ACAPS trials ) [Lorenz, 2007]
    • thickening of IMT correlates with the presence of traditional vascular risk factors (BMI, hypertension, hypercholesterolemia, diabetes, smoking)
    • some authors recommend including IMT and the presence of AS plaques among the classic vascular risk factors [Chambless, 2010]
    • some publications question the importance of IMT in predicting CV events [Costanzo, 2010] [Ruijter, 2012]
  • detection of subclinical atherosclerosis is important in patients with borderline risk and multiple risk factors, as it moves the patient into the high-risk category (SCORE ≥ 5%) with all therapeutic consequences
  • pharmacological studies have shown a reduction in the rate of progression of IMT with hypolipidemic therapy and antihypertensive drugs (ACAPS, METEOR)
    • rosuvastatin did not induce disease regression
  • on the other hand, a meta-analysis of 41 randomized trials showed regression of cardiovascular events with hypolipidemic drugs but did not show a relationship between a decrease in CV events and a regression of IMT [Costanzo, 2010]
  • an increase in IMT can also be found in non-atherosclerotic diseases (e.g., Takayasu´s arteritis)

I. Risk factors used to stratify CV risk according to ASCVD Risk Estimator Plus

  • sex
  • race
  • blood pressure
  • total cholesterol, LDL, HDL
  • history of diabetes and smoking
  • therapy (antithrombotic therapy, statins, antihypertensive drugs)

II. Target organs subclinical damage

  • left ventricular hypertrophy
  • sonographically proven thickening of the arterial wall (carotid IMT ≥ 0.9 mm) or the presence of atherosclerotic plaques (atherosclerosis)
  • ankle-brachial pressure index (ABPI) ratio < 0.9
  • slight increase in serum creatinine (115-133 μmol / l)
  • microalbuminuria (30-300 mg / 24hrs)
  • ↓ glomerular filtration rate (< 60ml / min / 1.73 m3)

III. Clinical manifestation

  • cerebrovascular disease
  • heart disease
    • myocardial infarction
    • angina pectoris
    • chronic congestive heart failure (CHF)
  • aneurysms
    • a serious complication that can occur anywhere in your body
    • besides sudden life-threatening rupture, a slow leak is possible. If a blood clot within an aneurysm dislodges, it may block an artery ostium and cause hypoperfusion
  • renal impairment
    • diabetic/non-diabetic nephropathy
    • decrease in renal function (serum creatinine > 133 μmol/L)
  • peripheral vascular disease (PAD)
  • advanced retinopathy
    • with hemorrhage or exudates
    • papilledema (optic disc swelling)
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Vascular risk factors
link: https://www.stroke-manual.com/vascular-risk-factors/