( ( ( ( ( ( atherosclerosis , ) or ) ( hardening ( of ( the arteries ) ) ) ) , ) ( which ( can ( lead ( to heart ) ) ) ) ) ( ( ( attacks and ) strokes ) . ) )
(ROOT (S (NP (NP (NNS atherosclerosis)) (, ,) (CC or) (NP (NP (VBG hardening)) (PP (IN of) (NP (DT the) (NNS arteries)))) (, ,) (SBAR (WHNP (WDT which)) (S (VP (MD can) (VP (VB lead) (PP (TO to) (NP (NN heart)))))))) (VP (VP (VBZ attacks)) (CC and) (VP (VBZ strokes))) (. .)))
atherosclerosis , or hardening of the arteries, which can lead to heart attacks and strokes .
(ROOT (S (NP (DT A) (NN heart) (NN attack) (CC or) (NN stroke)) (VP (VBZ is) (ADVP (RB often)) (NP (NP (DT a) (NN result)) (PP (IN of) (NP (JJ untreated) (NNS atherosclerosis))))) (. .)))