title: Perioperative myocardial infarctions are common and often unrecognized in patients undergoing hip fracture surgery.
abstract: BACKGROUND
  The aim of this prospective cohort study was to assess the incidence and characteristics of acute myocardial infarction in patients undergoing surgery for acute hip fracture.
  
  
  METHODS
  A consecutive cohort of patients (n = 200, 68 men) referred to acute surgical correction of hip fracture was studied. Troponin T (TnT) measurements and electrocardiographic (ECG) recordings were performed at admission, before operation, and on the first and 2nd postoperative days, which were used for diagnosis.
  
  
  RESULTS
  The age of the patients ranged from 32 to 98 years (mean, 80.8 years), and 65 patients had a history of coronary artery disease. A significant rise in TnT as a sign of myocardial infarction was observed in 71 patients (35.5%), and 25 of them had a TnT elevation exceeding five times the upper normal limit. TnT elevation was observed in 36 patients (51%) already before surgery. Seven patients (10%) had ST elevation myocardial infarction, 23 patients (32%) had new ST depressions, and 21 patients (30%) had no new ST segment changes in the serial electrocardiographic recordings. In 40 patients (56%), the perioperative myocardial infarction was the first manifestation of coronary artery disease. Multivariate logistic regression revealed that old age (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.02-1.10; p = 0.002), earlier revascularization (OR, 3.29; 95% CI 1.12-9.73; p = 0.03), and heart failure (OR, 2.42; 95% CI 1.04-5.61; p = 0.04) were independent predictors of TnT elevation. Majority of myocardial infarctions were asymptomatic or unrecognized. Evidence-based medications of myocardial infarction were seldom started and cardiologist was consulted in 12 patients (16.9%).
  
  
  CONCLUSIONS
  Patients with hip fracture often develop asymptomatic and clinically unrecognized perioperative myocardial infarctions. Earlier diagnosis and appropriate treatment of cardiac infarction may improve survival of hip fracture patients.
  
  
  METHODS
  Epidemiologic study, level III.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, Turku University Hospital, Turku, Finland.
authors.forename: Pauliina
authors.initials: P
authors.lastname: Hietala
authors.forename: Marjatta
authors.initials: M
authors.lastname: Strandberg
authors.forename: Niko
authors.initials: N
authors.lastname: Strandberg
authors.forename: Eero
authors.initials: E
authors.lastname: Gullichsen
authors.forename: K E Juhani
authors.initials: KE
authors.lastname: Airaksinen
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D017023:Coronary Angiography; D004562:Electrocardiography; D005260:Female; D005387:Finland / Q000453:epidemiology; D005500:Follow-Up Studies; D005592:Fracture Fixation; D006620:Hip Fractures / Q000150:complications / Q000601:surgery*; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology; D059035:Perioperative Period; D011379:Prognosis; D011446:Prospective Studies; D012307:Risk Factors