Stephen Sackur speaks to a brilliant heart surgeon - veteran of more than 30,000 operations - but his growing international reputation rests less on his medical skill, more on his business brain. He wants to do for major surgery what Henry Ford did for the motor car - make it affordable for the masses, by means of mass production. He's building what he calls medical cities across India and beyond - but can this vision of delivering a public good for private profit really change healthcare around the world?