Does coagulation differ between elderly and younger patients undergoing cardiac surgery?

Abstract

OBJECTIVE: Multiple improvements allow cardiac surgery in an increasingly older population. It is still unclear whether perioperative hemostasis differs between elderly and younger patients. DESIGN: Prospective, observational study. SETTING: Single institutional study at an urban, university-affiliated hospital. PATIENTS: Twenty-one consecutive patients aged over 80 years and 21 consecutive patients aged under 60 years undergoing first-time elective aortocoronary bypass grafting. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Modified thromboelastography (TEG) using different activators [intrinsic TEG (InTEG); extrinsic TEG (ExTEG); fibrinogen TEG (fibTEG)] was carried out to measure coagulation time [CT = reaction time (r)], clot formation time [CFT = coagulation time (k)], and maximum clot firmness [MCF = maximal amplitude (MA)]. Measurements were performed before surgery, at the end and 5 h after surgery on the intensive care unit (ICU), and on the morning of the 1st postoperative day (POD). Blood loss was slightly higher in the elderly than in the younger patients. Most TEG data were already significantly different between elderly and younger patients at baseline, indicating altered coagulation in the elderly prior to surgery (hypocoagulability). After surgery and on the ICU, elderly patients showed similar alterations in TEG to those of the younger patients (e.g. InTEG-CT: from 183+/-21 to 239+/-28 s versus from 146+/-15 to 186+/-26 s). On the 1st POD, most TEG data had returned almost to baseline values, however, they were still different between elderly and younger patients. CONCLUSIONS: Elderly cardiac surgery patients already showed moderately altered coagulation prior to surgery. Thus elderly patients may be at risk of developing postoperative alterations in hemostasis on the ICU. The exact reasons for the impaired coagulation in the elderly remains to be determined.