When Charles Riegel underwent surgery after a heart attack in 1996, no one could have guessed that his operation would lead to a Supreme Court decision that could affect the safety of patients across the US.

During surgery, an inflatable catheter designed to open Riegel’s coronary artery ruptured, leaving him severely injured. Riegel and his wife sued Medtronic, the manufacturer of the device, but defence lawyers argued that the firm could not be held responsible as the catheter had been approved by the Food and Drug Administration. Last week, the Supreme Court agreed, saying that this ruled out legal action. …