• Surgery;
  • coronary artery bypass grafting;
  • Pharmacology;
  • nifedipine


The management of the period after hypothermic cardiopulmonary bypass has been compared in a group of patients maintained on nifedipine therapy, a group who had the drug withdrawn at least 24 hours prior to cardiac surgery, and a control group who had never received calcium antagonists. Patients in the drug withdrawal group were significantly more likely to need vasodilator intervention than the treated (p < 0.001) or the control (p < 0.05) groups. Although nifedipine withdrawal appeared to reduce the need for inotropic support, compared to treated (p <0.001) and control groups (p <0.005), this may be at the cost of increasing systemic vascular resistance. This observation, coupled with reports of a rebound phenomenon following abrupt withdrawal of calcium antagonist therapy, suggests that nifedipine should be continued up to the time of surgery.