Do I have a medical malpractice/negligence case

My husband was diabetic for years, he had a stent placed in his heart in 2003 and suffered broken hips 1 in 2011 the other in 2013. despite these health problems he was seen 3/2014 by his primary and a couple months later by his cardiologist both telling him every was doing great,despite his swollen/discolored legs. in Aug 2014 he died of cardiac arrest-noted on the death certificate, the coroner had said it was most likely a blood clot. Shouldn't one or both of his doctors have done some type of testing or treatment to help him avoid blood clots?