Hong Kong health authorities have opened an investigation into an alleged medical blunder involving an improperly sealed catheter that led to the death of a 75-year-old man following a heart procedure at Tuen Mun Hospital.The Hospital Authority said on Thursday that the patient, who had a history of chronic obstructive pulmonary disease and high cholesterol, was admitted on Wednesday last week after his respiratory condition worsened.His health deteriorated further following an acute heart...