( ( Left untreated ) ( , ( it ( ( can ( lead ( to ( ( ( ( ( amputation , ) ( heart attacks ) ) , ) and ) strokes ) ) ) ) . ) ) ) )
(ROOT (S (S (VP (VBN Left) (S (ADJP (JJ untreated))))) (, ,) (NP (PRP it)) (VP (MD can) (VP (VB lead) (PP (TO to) (NP (NP (NN amputation)) (, ,) (NP (NN heart) (NNS attacks)) (, ,) (CC and) (NP (NNS strokes)))))) (. .)))
Left untreated, it can lead to amputation, 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))))) (. .)))