I have been told that i have had basal ganglia lacunar infarct, will this lead to demincia?

Yes, specifically the so called vascular dementia, result of multiple strokes along the years. Treating their cause, if known, may delay significantly onset of dementia.

If you fail to treat risk factors for stroke such as hypertension, diabetes, hypertriglyceridemia, you would be at risk for additional small strokes, leading to a lacunar state, and full-fledged vascular dementia. This can be delayed and perhaps even controlled by prevention. See your doctor and get this handled.