Regarding Stroke

What is stroke?

Stroke occurs when a brain vessel is occluded (ischemic stroke) or ruptured (hemorrhagic stroke). Consequences on patients from an occlusion or rupture of a brain vessel depends on the size and location of the resulting brain lesion.

Vessel Rapture (15%)
+
Artery obstruction (85%)

8% of deaths in Greece are caused by strokes[1]. Despite a reduction in mortality rates per stroke through modern therapies, the aging population leads to an increase in the total number of strokes per year. Recent epidemiological data from the region of Evros estimate the annual incidence of strokes to 587 per 100,000 people, 80% of whom are ischemic[2]. By projecting this rate to the Greek population, the total number of ischemic strokes could be over 50,000 per year.

Stroke Types

Ischemic Stroke

  • 1. Large vessel atherosclerosis
  • 2. Cardio embolism
  • 3. Small vessel disease
  • 4. Cryptogenic (undefined cause)[3],[4]

Hemmorrhagic Stroke

Hemorrhagic strokes may be less common than ischemic strokes but are more severe. The main cause of a brain artery rupture is uncontrolled arterial hypertension. Subarachnoid hemorrhage is a rare cause of hemorrhagic strokes that is caused by a rupture of a brain aneurysm.

Transient Ischemic Attack
Transient ischemic attack is the mildest form of ischemic stroke and does not provoke long-term neurological deficits. However, it provides a window of opportunity for diagnosing its underlying cause and adapting the prophylactic treatment in order to avoid a subsequent, possibly debilitating, ischemic stroke [5].
Cryptogenic Stroke
Cryptogenic stroke may be the commonest type of ischemic stroke[6]. Despite the progress being made on diagnostic methods, failure to accurately pinpoint a specific cause of stroke is common in clinical practice. Further diagnostic work-up after hospital discharge is therefore commonly required to select the proper secondary stroke prevention treatment. Cryptogenic stroke in Greece is the most common type of ischemic stroke, representing annually up to 220 cases per 100,000 patients, according to the most recent epidemiological data available[2]. Recent studies have revealed that paroxysmal atrial fibrillation is a major cause of cryptogenic strokes. Atrial fibrillation is a type of heart arrhythmia that is usually not life-threatening per se but can lead to cardiac thrombi formation that may embolize brain arteries, leading to ischemic strokes that are commonly severe[8]. Diagnosis through electrocardiography (ECG) may be challenging in its paroxysmal form, in which atrial fibrillation interrupts periods of normal cardiac rhythm. It may occur that runs of atrial fibrillation are not detected during continuous ECG monitoring during hospital stay because episodes may be infrequent[9]. Diagnosing atrial fibrillation is important since initiation of anticoagulation is extremely effective in reducing stroke risk by 2/3[10].

Regular Cardiac rhythm

A small pulse of electricity travels rapidly through the heart to cause muscle contraction.

Atrial Fibrillation

In atrial fibrillation, the upper chambers of the heart contract faster than the rest of the heart.

Risk scales

Risk scales may be used to preselect patients with cryptogenic stroke at high risk of underlying paroxysmal atrial fibrillation in order to proceed with further diagnostic work-up. The risk of atrial fibrillation is increased with age[11]. Atrial fibrillation prevalence is 3-4% in the general population but increases up to 20-30% in those over 80[12]. HAVOC score has been found to be reliable to predict paroxysmal atrial fibrillation detection in patients with cryptogenic stroke[13].
ΗAVOC score[14]
Risk Factor Points
Congestive heart failure 4
Hypertension 2
Age >75 2
Vascular disease 2
Coronary artery disease 2
Peripheral arterial disease 1
Obesity (body mass index >30) 1
 0-4 grades: small risk, 5-9 grades: moderate risk, 10-14 grades: high risk of underlying paroxysmal atrial fibrillation

In high-risk patients it is important to prolong ECG monitoring to detect paroxysms of atrial fibrillation, to shift from antiplatelet (common secondary prevention treatment for cryptogenic stroke) to anticoagulation therapy (indicated for secondary prevention of cardioembolic stroke due to atrial fibrillation) in eligible patients[15]. The more we prolong ECG recording the more likely the detection of arrhythmia; best results have been repeatedly reported with implantable devices[10].

4h ECG Holter may detect a mere 1.3% of cases compared to an implantable device[16]. Even 30-day ECG recording only detects 23% of patients. Approximately one in three patients with cryptogenic stroke and negative initial diagnostic work-up is found to present with paroxysmal atrial fibrillation as detected by an implantable cardiac monitoring device[17].
The Hellenic Neurological Society, the Work Team on Stroke of the Hellenic Society of Cardiology and the Hellenic Society of Cerebrovascular Diseases have published a consensus document on atrial fibrillation detection in patients after cryptogenic stroke[18].

[Click here to see the article http://www.hellenicjcardiol-gr.gr/index.php/hjc/article/view/283]

REFERENCES

[1] Wilkins E. et Al. European Cardiovascular Disease Statistics 2017; 2017:192

[2] Tsivgoulis G, et al. Stroke. 2018 Feb;49(2):288-295.

[3] Petty GW, et al. Stroke. 1999;30:2513-2516.

[4] Kolominsky-Rabas PL, et al. Stroke. 2001;32:2735-2740.

[5] Fonseca AC, et al. Eur Stroke J. 2021;6(2):V.

[6] Lee BI, et al. Cerebrovasc Dis. 2001;12:145-151.

[7] Kleindorfer DO, et al. Stroke. 2021;52(7):e364-e467.

[8] Wolf PA, et al. Stroke. 1991;22:983–8.

[9] Kurka N, et al. Stroke 2015; 46: 560 – 563.

[10] Stroke Prevention in Atrial Fibrillation Study. Circulation. 1991;84:527-539.

[11] Tsivgoulis G, et al. J Stroke. 2019;21(3):302-311.

[12] Goudevenos JA, et al. Europace. 1999;1:226-33

[13] Zhao SX, et al. Ther Adv Neurol Disord. 2019;12:1756286419842698.

[14] Kwong, C., et al. Cardiology, 138(3), 133–140.

[15] Writing Group Members, January CT, Wann LS, et al. Heart Rhythm. 2019;16(8):e66-e93.

[16] Choe WC, et al. Am J Cardiol 2015; 6:889–893.

[17] Asaithambi G, et al. J Electrocardiol. 2018;51:973-976.

[18] http://www.hellenicjcardiol-gr.gr/index.php/hjc/article/view/283