Evidence‑Based Distinction Between Lacunar Infarcts (LACI) and Partial Anterior Circulation Infarcts (PACI)
Imaging Definitions
- Lacunar infarcts appear on CT or MRI as subcortical lesions < 1.5 cm in diameter, located deep in the brain or brainstem, and lack any cortical involvement. 1
- The definition of LACI requires the absence of any concomitant cortical infarct on imaging studies. 2
- Partial anterior circulation infarcts are cortical lesions situated within the territory of the large anterior‑circulation arteries and are generally larger than lacunar strokes. 3
Clinical Presentation
- Patients with LACI commonly present with classic lacunar syndromes such as pure motor hemiparesis and exhibit lower overall stroke severity. 3
Pathophysiology
- LACI is caused by occlusive arteriopathy of small penetrating vessels, primarily due to lipohyalinosis and micro‑atheroma linked to hypertension and diabetes; atherosclerosis is not the usual mechanism. 4
- PACI is most often related to large‑artery atherosclerosis or embolic mechanisms (artery‑to‑artery or cardioembolic). 4
- Before confirming a diagnosis of LACI, clinicians should exclude potential cardioembolic sources and ipsilateral large‑artery stenosis. 5
Prognostic Implications – Mortality
- Two‑year survival for patients with LACI is approximately 85 %, markedly higher than for other ischemic stroke subtypes. 6
- One‑year mortality after a lacunar stroke is about 1.4 % versus 8.1 % for atherosclerotic strokes. 6
- Within the first 90 days, LACI mortality is roughly 3.3 %, the lowest among all ischemic stroke categories. 6
Prognostic Implications – Cardiac Risk
- Individuals with small‑vessel disease (LACI) have a lower risk of subsequent coronary events compared with patients suffering other stroke subtypes. 7
- Abnormal cardiac stress test results occur in 50 % of patients with atherosclerotic stenosis (more typical of PACI) versus 23 % in patients with other stroke etiologies, including lacunar disease. 7
Diagnostic Recommendations
- Even when a patient exhibits a classic lacunar syndrome, imaging confirmation and systematic exclusion of cardioembolic sources and large‑artery stenosis are essential to avoid misclassification. 5