Transient ischemic attack: early signs and stroke prevention

A transient ischemic attack (TIA) is a brief episode of focal neurological symptoms caused by a localized disruption of blood flow in the brain, spinal cord, or retina, without evidence of tissue infarction on imaging. This "tissue" definition replaces the outdated time threshold (up to 24 hours). The concept is simple: if there are no signs of tissue damage, we call it an attack; if there are, it's a stroke, even if the symptoms resolve. [1]

An attack is not a "mini-stroke," but a high-risk signal: the risk of stroke increases significantly in the coming days and weeks, especially in the first 48 hours. Establishing rapid screening and preventative care routes dramatically reduces this risk. [2]

The modern approach is based on three pillars: urgent diagnosis, rapid initiation of prevention of recurrent events (antiplatelet agents or anticoagulants depending on the cause, correction of risk factors), and targeted correction of the causes (carotid artery stenosis, atrial fibrillation, dissection, etc.). [3]

Epidemiology and short-term risks

The prevalence of attacks varies by region; in the United States, estimates in the early 2000s were around 240,000 episodes per year, and the 90-day risk of stroke was historically estimated at 10-18%. In the era of rapid "TIA clinics" and early prevention, average risks are lower, but the first 2-7 days remain critical. [4]

Systematic reviews and large registries show that expedited screening pathways and immediate treatment reduce early recurrent strokes by tens of percent (a classic example is the EXPRESS program). In modern networks, the risk of 90-day stroke after an attack can drop to approximately 3-5% if the patient is screened and treated within the first 24 hours. [5]

Table 1. Epidemiological landmarks

Indicator	Typical landmark	Comment
90-day risk of stroke after attack (historical cohorts)	10-18%	Decreases on fast routes. [6]
Maximum risk	The first 48 hours	Half of the relapses may occur in the early period. [7]
Modern rapid response networks	≈3-5% by day 90	With immediate examination and treatment. [8]

Reasons

The main mechanisms are thromboembolism in atrial fibrillation, atherothrombosis of large arteries (including critical stenosis of the internal carotid artery), diseases of small arteries (lacunar mechanisms), less commonly dissections of the carotid/vertebral arteries, paradoxical embolism with an open oval window, etc. Determining the source is fundamentally important: the choice of antiplatelet agents, anticoagulation, and vascular interventions depends on it. [9]

Table 2. Common causal categories and what to look for

Category	What to suspect	What will help confirm
Cardioembolism (atrial fibrillation, etc.)	Paroxysmal arrhythmia	Long-term rhythm monitoring, echocardiography. [10]
Atherosclerosis of large arteries	Internal carotid stenosis, plaques	Ultrasound duplex, CT angiography/MR angiography. [11]
Small artery disease	Lacunas, risk factors	MRI with diffusion-weighted imaging. [12]
Dissection	Young age, neck pain, injury	CT angiography/MR angiography. [13]
Paradoxical embolism (PFE)	In young people, cryptogenic events	Echo with bubble test; closure - not in "pure" attack without infarction. [14]

Risk factors

Modifiable factors: hypertension, dyslipidemia, smoking, diabetes, obesity, low physical activity, and alcohol abuse. Non-modifiable factors: age, family history, and male gender. Control of blood pressure, lipids, and lifestyle are key to reducing future risk. [15]

Table 3. What most influences recurrence risk (and what we influence)

Factor	What to do
Arterial hypertension	Achieve <130/80 mmHg as tolerated. [16]
Lipids (low density lipoproteins)	High-intensity statin therapy; aim <70 mg/dL (≈<1.8 mmol/L). [17]
Smoking	Complete refusal, termination programs. [18]
Diabetes	Glycemic control, individual goals. [19]

Pathogenesis and "tissue" logic

The underlying cause is a short-term critical drop in perfusion in a specific artery's circulation. If blood flow is quickly restored and no infarction occurs, MRI diffusion will show no focal restricted diffusion; this is what distinguishes an attack from a stroke. However, up to 60% of clinical "attacks" may have a focal diffusion pattern—in this case, a stroke with rapidly resolving symptoms. [20]

Symptoms

Sudden focal symptoms include weakness or numbness on one side, impaired speech, vision (including amaurosis fugax), coordination, and sensory impairment. Onset is sudden, and symptoms resolve completely within minutes or hours. Even with complete resolution, the situation should be considered urgent. [21]

Diagnostics: What, When, and Why

1. Immediate assessment using the "stroke-like" principle: determine the time of onset and current symptoms, measure blood pressure, glucose, and saturation; rule out mimicry (e.g., hypoglycemia). Simultaneously, arrange an urgent referral to a stroke specialist/TIA Clinic—ideally within 24 hours. [22]
2. Neuroimaging. If available, MRI of the brain with diffusion is the most sensitive method for confirming the absence of infarction and searching for "mimics." If MRI is unavailable, computed tomography (to rule out hemorrhage) with targeted angiography to evaluate the arteries. [23]
3. Imaging of the arteries of the head and neck: duplex ultrasound of the carotid arteries, computed tomography angiography or magnetic resonance angiography - to search for stenoses/occlusions and dissections. [24]
4. Cardiac assessment and arrhythmia detection. Electrocardiogram (ECG) for all; prolonged rhythm monitoring (24-30 days or more) significantly increases the detection of atrial fibrillation compared to short recordings (CRYSTAL-AF data, etc.). Echocardiography - as indicated (embolic sources). [25]
5. Basic tests: complete blood count, platelets, coagulogram, lipids, glucose/glycated hemoglobin, electrolytes; additional tests - as clinically indicated (vasculitis, thrombophilia - selectively). [26]

Table 4. Visualization methods: what each one provides

Method	What does it reveal best?	When it is especially useful
MRI with diffusion	Acute infarction, "facial expressions"	The gold standard of "tissue" definition. [27]
CT scan of the head	Hemorrhage, gross pathologies	Fast and accessible, start screen. [28]
CT angiography/MR angiography	Stenosis, occlusion, dissection	Planning tactics for carotid disease. [29]
Duplex ultrasound	Hemodynamic stenosis of the carotid artery	Screening and dynamics. [30]

Differential diagnosis

Common "mimics": migraine with aura, focal seizures with postictal Todd paresis, hypoglycemia, vestibular paroxysms, functional impairment, transient global amnesia. Vascular stereotype (sudden onset, focality, correspondence to arterial circulation), neuroimaging, and laboratory "red flags" help distinguish these. [31]

Table 5. Attack against "mimics"

State	Pros	Tips against
Attack	Sudden focality, vascular pool	No migraine/attack triggers, MR diffusion is negative. [32]
Migraine with aura	Gradual increase, “positive” phenomena	Atypical foci, young people without risk factors. [33]
Seizure + Todd's paresis	Piecemeal symptoms, postictal period	History of epileptic phenomena/EEG. [34]
Hypoglycemia	Sweating, tremors, low glucose	Regression against the background of glycemic correction. [35]

Short-term risk assessment

The ABCD2 score (age, blood pressure, clinical presentation, duration, diabetes) has historically been used for triage, but it is insufficient for determining urgency: some patients with a low score are still considered high risk (especially based on MRI/angiography findings). Advanced models, such as ABCD3-I (which takes into account recurrent attack and imaging data), are more accurate in predicting risk, but are more expensive and complex. Current guidelines prioritize urgent evaluation of all patients, without delays based on scores. [36]

Table 6. ABCD2 (quick reminder) and ABCD3-I (expansion)

Parameter	ABCD2 (0-7)	ABCD3-I complements
Clinic/time/factors	Yes	+ re-attack ("Dual"), + visualization (infarction/stenosis)
Application	Rough stratification	More accurate forecast, more difficult in practice
What's important in 2025	Does not delay the examination	The decision to examine everyone is immediate. [37]

Treatment

Immediately (first contact):
If an attack is suspected and there are no signs of bleeding, aspirin 300 mg is prescribed as soon as possible (unless there are contraindications) and a specialist assessment is arranged within 24 hours. This is the position of NICE and several national guidelines. In parallel, blood pressure, glycemia, temperature, and hydration should be monitored. [38]

Antiplatelet therapy:
For most non-cardioembolic attacks, dual therapy with aspirin plus clopidogrel for a short period is considered initial: large randomized trials, CHANCE and POINT, demonstrated a reduction in early ischemic events with the addition of clopidogrel, with a compromise in bleeding with a longer course. The optimal duration is approximately 21 days (up to 30 days), followed by a switch to a single antiplatelet agent. Aspirin plus ticagrelor is an alternative in some patients, but bleeding is more common. [39]

Anticoagulation in Atrial Fibrillation
If the attack is due to atrial fibrillation and there is no infarction based on imaging, it is reasonable to initiate a direct oral anticoagulant immediately (unless contraindicated). In the case of a stroke (not an attack), the timing is determined by the severity and risk of hemorrhagic transformation; modern trials (ELAN, TIMING) support early initiation in carefully selected situations. [40]

Carotid disease: when to intervene
For symptomatic 70-99% ipsilateral internal carotid artery stenosis, carotid endarterectomy is recommended if the surgical risk is <6%, and within 14 days of the event. For 50-69% stenosis, the benefit is more modest and depends on age, gender, and comorbidities. Stenting is considered in patients with high surgical risk or unfavorable anatomy. [41]

Prevention for years to come
Target values: blood pressure <130/80 mmHg (if tolerated), low-density lipoprotein <70 mg/dL - high-intensity statin with the addition of ezetimibe/PCSK9 inhibitors if needed; smoking cessation; Mediterranean-type diet; regular physical activity. These measures are equally important after stroke and after an attack. [42]

Table 7. Antithrombotic therapy during an attack (simplified)

Situation	The first 21-30 days	After 21-30 days
Non-cardioembolic attack	Aspirin + clopidogrel (short course)	One antiplatelet agent (aspirin or clopidogrel) [43]
Alternative	Aspirin + ticagrelor (selective)	One antiplatelet agent
Atrial fibrillation, no infarction	Direct oral anticoagulant immediately	Continue anticoagulation

Table 8. Carotid revascularization (post-symptoms)

Degree of stenosis	Preferred tactics	Deadlines
70-99%	Endarterectomy with acceptable risk	Preferably ≤14 days from symptoms
50-69%	Consider individually	Early consultation with a vascular surgeon
<50%	Conservative optimization	Intervention is not indicated
[44]

Heart Rate Monitoring: Why It's Critical

A brief electrocardiogram misses paroxysms. Extended monitoring (days to weeks) significantly increases the detection of atrial fibrillation; implantable recorders detect arrhythmia in a significant proportion of patients over months to years (CRYSTAL-AF). The "catch" directly depends on the duration of observation. [45]

Table 9. Detectability of atrial fibrillation with different strategies

Strategy	Typical horizon	Relative detectability
Holter 24-48 hours	1-2 days	Low (skips paroxysms)
External loop recorder	2-4 weeks	Above, an acceptable compromise
Implantable monitor	Months-years	Maximum detectability (CRYSTAL-AF, etc.). [46]

When to see a doctor

Always - immediately. Any sudden focal symptom (speech, face, arm, leg, vision, coordination), even if it has already passed, is a reason to immediately call an ambulance or go to a stroke center. "Wait first and decide later" is dangerous during attacks. [47]

Prevention

1. Control blood pressure to target values.
2. High-intensity statins with targeted reduction of low-density lipoproteins; if necessary, ezetimibe/PCSK9 inhibitors.
3. Complete cessation of smoking; moderate aerobic exercise regularly; Mediterranean diet.
4. In atrial fibrillation - long-term anticoagulation according to the risk scale. [48]

Forecast

With prompt evaluation and initiation of therapy, most patients avoid early stroke. The worst short-term outcomes are in patients with MRI diffusion stenosis (essentially a stroke), severe carotid artery stenosis, and unrecognized atrial fibrillation. Long-term prognosis is determined by risk factor control and treatment adherence. [49]

Frequently asked questions

1) "If the symptoms have gone away, maybe it's not a big deal?"
Gone doesn't mean safe. This is a "warning shot": the risk is highest in the first 2-7 days, and a quick route dramatically reduces it. [50]

2) "Does everyone need dual antiplatelet therapy?"
No. A short course of aspirin and clopidogrel is useful for non-cardioembolic attacks and minor strokes, started within 24 hours; then monotherapy is used. The choice and duration are determined by a specialist, taking into account the risk of bleeding. [51]

3) "Are dual antiplatelet agents also needed for atrial fibrillation?"
No. Anticoagulation with a direct oral anticoagulant is required (unless there are contraindications); dual antiplatelet agents do not replace anticoagulation. In the case of a "pure" attack, anticoagulation can be started immediately. [52]

4) "When is carotid surgery performed?"
For symptomatic stenosis of 70-99% - as soon as possible, within 14 days, endarterectomy is preferred. For 50-69%, the decision is made on an individual basis; for <50% - medical management. [53]

5) "Should a patent foramen ovale be closed?"
Closure is discussed in selected patients after a stroke, not in a "pure" attack without infarction. The decision is made by a multidisciplinary team. [54]

Table 10. “Quick start” for suspected attack (outpatient/emergency department)

Step	Action	For what
Straightaway	Aspirin 300 mg (if there are no contraindications)	Reducing the risk of early events. [55]
≤24 h	Visit to a stroke specialist / TIA Clinic	Window of opportunity for prevention. [56]
≤24-48 h	MRI with diffusion + arterial imaging	Confirm the "tissue" definition and reason. [57]
≤7 days	Advanced rhythm monitoring	To detect paroxysmal fibrillation. [58]

Table 11. What definitely not to do

Error	What is dangerous?
Wait for symptoms to recur	The period of highest risk is missed. [59]
Rely only on ABCD2 score for urgency	Risk may be underestimated in some patients. [60]
Delay in visualization of arteries	Missing stenosis, dissection. [61]
Prescribe dual antiplatelet agents "for a long time"	Extra bleeding without benefit. [62]