Peri-operative silent myocardial ischaemia in patients undergoing lower limb joint replacement surgery: an indicator of postoperative morbidity or mortality

One hundred and twenty-seven patients undergoing major lower limb joint rep lacement surgery were studied to determine the incidence of silent myocardi al ischaemia and to ascertain any link between pre-operative cardiac risk f actors, silent myocardial ischaemia and postoperative morbidity. Patients u nderwent ambulatory ECG monitoring for 4 days (on the pre-operative night a nd for 3 days postoperatively). Postoperative cardiorespiratory symptomatol ogy and morbidity was assessed by questionnaire at 3 months. Eighty-seven p atients had risk factors for silent myocardial ischaemia; 42 patients (30 w ith risk factors) had peri-operative silent myocardial ischaemia. The media n ischaemic loads (range) were 1.04 (0.32-13.31) min.h(-1) pre-operatively and 5.53 (0.26-56.39), 6.69 (0.04-42.71) and 1.23 (0.1-53.74) min.h(-1) on postoperative days 1-3, respectively. Risk factors did not predict the occu rrence of silent myocardial ischaemia or an increased ischaemic load pre-op eratively or overall postoperatively. New symptoms (chest pain, palpitation s, breathlessness or fatigue) were associated with both silent myocardial i schaemia and ischaemic load (p < 0.05). Thus cardiac risk factors do not pr edict the occurrence of silent myocardial ischaemia or adverse outcome. Per i-operative silent myocardial ischaemia was associated with increased posto perative fatigue.