His Coumadin has been on hold for eye surgery.
 He has a history of blood clots 
(ROOT (S (NP (PRP$ His) (NNP Coumadin)) (VP (VBZ has) (VP (VBN been) (PP (IN on) (NP (NN hold))) (PP (IN for) (NP (NN eye) (NN surgery))))) (. .)))
(ROOT (S (NP (PRP He)) (VP (VBZ has) (NP (NP (DT a) (NN history)) (PP (IN of) (NP (NN blood) (NNS clots)))))))
( ( His Coumadin ) ( ( has ( ( been ( on hold ) ) ( for ( eye surgery ) ) ) ) . ) )
( He ( has ( ( a history ) ( of ( blood clots ) ) ) ) )