Hong Kong health authorities have opened an investigation into a suspected medical blunder involving an improperly sealed catheter used in a heart operation on a 75-year-old man who later died 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 attack,...