Possible mechanisms and controversies of protective effects of risk factors against stroke severity

Incidence and risk factors for diffusion-weighted imaging (+) lesions after intracranial stenting and its relationship with symptomatic ischemic complications

BACKGROUND AND PURPOSE

Little is known about high-signal lesions in magnetic resonance diffusion-weighted imaging (DWI [+]) after stenting for intracranial atherosclerotic stenosis. This study aimed to evaluate the incidence, distribution, risk factors, and clinical implications of DWI (+) after intracranial stenting.

METHODS

A total of 123 patients (male:female=88:35, mean age, 64.1 years) with symptomatic intracranial atherosclerotic stenosis (mean stenosis, 76.1±7.7%) underwent both stenting and poststenting DWI. The incidence, distribution (embolic-alone versus stenosis-associated perforator/mixed), and risk factors of DWI (+) and its relationship with symptomatic ischemic complications (SIC, including stroke or transient ischemic attack) were retrospectively evaluated.

RESULTS

Forty-three patients (35.0%) had DWI (+). Middle cerebral artery, smaller distal parent artery, and treatment-related dissection were independent risk factors for DWI (+) (P<0.05). SIC occurred in 4 patients (3.3%), all of whom had DWI (+). Of the patients with DWI (+), neither the number nor the volume of DWI (+) differed significantly between SIC and asymptomatic patients: median number/patient, 3.5 (range, 2-11) versus 2.0 (range, 1-11) and median volume/patient, 329.8 mm(3) (range, 76-883.5 mm(3)) versus 119.5 mm(3) (range, 32.5-873.0 mm(3)). However, SIC occurred more frequently in the stenosis-associated perforator/mixed type (3/11, 27.3%) than in the embolic-alone type (1/32, 3.1%; P<0.05).

CONCLUSIONS

The incidence of DWI (+) after intracranial stenting for intracranial atherosclerotic stenosis was 35.0%. Middle cerebral artery, smaller distal parent artery, and treatment-related dissection were independent risk factors for DWI (+). SIC occurred more frequently in the stenosis-associated perforator/mixed type than in the embolic-alone type.

The impact of smoking on the severity of acute ischemic stroke

OBJECTIVES

This study investigated the impact of smoking on the initial severity of acute ischemic stroke and examined its subsequent outcome.

METHODS

Patient data was collected from the Stroke Registry in the Chang Gung Healthcare System (SRICHS). A total of 2650 patients admitted for acute ischemic stroke from January to December 2009 were included. Baseline characteristics were compared between smokers and non-smokers. Factors affecting the initial severity and the recovery from neurological deficit were examined by logistic regression analysis. The patients were further divided according to stroke mechanism for subgroup analysis.

RESULTS

The total number of smokers and non-smokers was 817 (31.9%) and 1833 (69.1%), respectively. Univariate analysis showed that smokers had lower NIHSS scores on admission than did non-smokers (P<0.001). In subgroup analysis, smokers with small-vessel occlusions frequently had higher NIHSS scores on admission than did non-smokers (P=0.001). However, smokers with cardioembolic stroke had lower NIHSS scores on admission as compared to non-smokers (P=0.024). No subgroup had smoking as a significant factor for neurological recovery during hospitalization.

CONCLUSIONS

Smoking correlated with higher NIHSS scores on admission for small-vessel occlusion. Conversely, it was associated with lower NIHSS scores on admission for cardioembolism.