Etiology and Management of Lacunar Infarcts
Lacunar infarcts are subcortical strokes measuring <1.5 cm in diameter caused primarily by small vessel disease affecting penetrating arteries deep in the brain or brain stem, rather than by atherosclerosis that affects other stroke subtypes. 1
Etiology
Pathophysiology
- Lacunar infarcts result from occlusion of a single penetrating artery deep in the brain or brain stem 2
- Two main microvascular pathologies are responsible for lacunar infarcts:
- Size of lacunar infarcts correlates with underlying pathology:
Risk Factors
- Hypertension is a major risk factor for all lacunar infarcts 2
- Diabetes mellitus is significantly associated with smaller lacunes (≤7 mm), supporting the lipohyalinotic etiology 4
- Elevated LDL cholesterol is more strongly associated with larger lacunes (8-20 mm), supporting the microatheroma etiology 4
- Other risk factors include:
Clinical Presentation
- Patients typically present with one of the classical lacunar syndromes 1:
- Pure motor hemiparesis
- Pure sensory syndrome
- Sensorimotor stroke
- Ataxic hemiparesis
- Dysarthria-clumsy hand syndrome
Diagnosis
Imaging
- Diagnosis requires neuroimaging (CT or MRI) showing a small (<1.5 cm) subcortical infarct 1
- The term "lacunar infarct" should be reserved for cystic lesions smaller than 1 cm located in the basal ganglia, brain stem, or deep white matter 5
- Potential sources of cardioembolism and ipsilateral large-artery stenosis should be excluded to confirm the diagnosis 1
Differential Diagnosis
- Approximately 8% of patients with apparent lacunar infarcts have concurrent embolic lesions, suggesting a stroke etiology other than small vessel disease 6
- These patients tend to be older, more severely affected, and have worse functional outcomes 6
- A thorough diagnostic workup for possible embolic sources is necessary even in patients with imaging-defined lacunar infarcts 6
Management
Acute Management
- Standard acute stroke management protocols apply
- Antiplatelet therapy should be tailored according to lacunar infarct size:
- More aggressive antiplatelet and anticoagulation therapy may be beneficial for larger lacunar infarcts (10-20 mm) 3
Secondary Prevention
- Key elements in secondary prevention include 2:
- Antiplatelet drugs
- Careful blood pressure control
- Statin therapy
- Modification of lifestyle risk factors
Prognosis
Short-term Prognosis
- Lacunar infarcts have a favorable short-term prognosis 2:
- Low early mortality
- Reduced functional disability on hospital discharge
Long-term Prognosis
- Long-term prognosis is less favorable 7:
- Increased risk of death, mainly from cardiovascular causes
- Risk of recurrent stroke similar to other stroke subtypes
- Increased risk of cognitive decline and dementia
- Among stroke subtypes, patients with small-artery occlusion have the highest survival rate (85% at 2 years) 1
- Factors affecting long-term prognosis include 7:
- Age
- Vascular risk factors
- High nocturnal blood pressure
- Severity of cerebral small vessel disease at onset
Progression
- Asymptomatic progression of small vessel disease is a typical feature of lacunar infarcts 2
- Larger lacunar infarcts (10-20 mm) are more likely to show progression of motor deficits than smaller ones 3
Clinical Implications
- Despite their initially favorable course, lacunar infarcts should be regarded as a potentially severe condition rather than a benign disorder 2
- Patients require adequate management and rigorous follow-up due to the increased long-term risks 2
- Risk factor modification plays a crucial role in preventing recurrence and cognitive decline 7