You must realize that cardiovascular health is largely based on societal habits and diet. A doctor living and working in India largely unfamiliar with an American patients dietary, stress, and daily habits wouldn't be adequately equipped to treat an american patient for something as serious as Cardiovascular ailments. Not only that, but they would risk forfeiture of their insurance coverage by taking medical advice and treatment from a non-FDA approved medical provider. Further, foreign medical providers who may have plans to migrate to the US wouldn't participate as this would hinder any potential of them ever becoming licensed in the US.