Recent small subcortical infarction (RSSI) is defined as a small deep infarction in the territory of a perforating artery with maximum axial diameters (MAD) of less than 20 mm. Although RSSI is generally considered to be of a relatively favorable prognosis, about 13.5% to 43% of RSSI patients experience early neurological deterioration (END) in the acute phase, which often bring adverse effects on long-term outcomes. Although a number of risk factors for END have been identified previously, however, the risk factors of END and the underlying etiological mechanism are still ambiguous, and also the relevant intervention measures lack sufficient evidences, which is a thorny problem that clinicians have to face.

In this multicenter, large-sample prospective registry study, we ought to investigate the natural course of END in patients with RSSI. Exploring the risk factors and potential mechanism of its occurrence and development, and trying to establish a comprehensive predictive model for END that integrates multi-dimensional information including clinical symptom, demographic data, biochemical biomarker and image data, and so as to provide a valuable tool for clinical evaluation and early management. Simultaneously, our study will provide information for the design of therapeutic randomized controlled trials in the future.

RSSI patients within 72 hours of stroke onset were prospectively and consecutively enrolled from Janu 2015 to June 2024. After enrollment, Clinical data will be collected using an online electronic case report Form (e-CRF) at baseline and follow-up. Baseline data including demographic, first blood pressure, past and family history, past medications use, pre-stroke modified Rankin Scale score (mRS), assessment of mRS and NIHSS score on admission were recorded. After admission, NIHSS score was evaluated twice a day by two certified physicians, who were blinded to the study. laboratory tests including routine blood/biochemistry/renal function, etc.) Transthoracic echocardiogram, 24-hour Holter and neuroimages data including brain MRI/MRA/CTA/DSA, etc. were all collected. During hospitalization, the drug therapy (antiplatelet/anticoagulation, lipid-lowering, glucose lowering, antihypertensive, etc.) were also recorded. Early neurological deteriorations (END) were monitored by two certified physicians, who were blinded to the imaging, and the primary outcome of our study was the occurrence of END, which was defined as any increase of ≥ 2 points in the total NIHSS score or ≥ 1 point on the motor items of the NIHSS within 7 days of hospital admission with blind evaluation. And any new cerebrovascular events confirmed during hospitalization were recorded. By face-to face or telephone interviews, we extended the follow up to 1 year for our secondary outcome including ①percentage of patients with favorable functional recovery, defined as an mRS ≤1; ②Percentage of patients with new vascular events, defined as any stroke (ischemic or hemorrhage); ③Percentage of patients with the new clinical vascular events (ischemic stroke/ hemorrhagic stroke/ TIA/ MI/ vascular death) as a cluster and evaluated individually. ④Severe bleeding incidence (GUSTO definition), including fatal bleeding and symptomatic intracranial hemorrhage; ⑤ Incidence of symptomatic and asymptomatic intracranial hemorrhagic events; ⑥All-cause mortality; ⑦cognitive function (MOCA/MMSE score). The outcomes will be assessed by the neurologists blinded to study images. The quality control of all data will be held by the central center.

Inclusion Criteria:

1. Age ≥ 18 years;
2. Time from the last seen normal to enrollment ≤ 72 h.
3. Completion of brain MRI (T1/T2/Flair/DWI sequences at least). The lesion belonged to the territory of the penetrating artery( lenticulostriate area and pons) on the DWI sequence and at least one of the vascular examinations such as MRA, CTA or DSA was completed.

Exclusion Criteria:

1. Patients with low imaging quality affecting the evaluation of the data;
2. Vascular malformations, aneurysms, intracranial hemorrhagic diseases, brain abscesses, malignant space occupying lesions or other non-ischemic intracranial lesions;
3. Patients with combined malignancy, hematological disease and other systemic diseases with possible hypercoagulable state;
4. pre-stroke mRS ≥2 ;
5. END occurred before the completion of brain MRI after admission;
6. Acute endovascular treatment had been received or was planed to be done;
7. Pregnant or lactating women;
8. Participating in another ongoing study;
9. Refused to participate in the study.

prospectively enroll consecutive patients with acute RSSI within 72 hours of onset January 2015 to January 2024.