title: Application of support vector machine classifiers to preoperative risk stratification with myocardial perfusion scintigraphy.
abstract: BACKGROUND
  Myocardial perfusion single-photon emission computed tomography (SPECT) has been used for risk stratification before non-cardiac surgery. However, few authors have used mathematical models for evaluating the likelihood of perioperative cardiac events.
  
  
  RESULTS
  This retrospective cohort study collected data of 1,351 patients referred for SPECT before non-cardiac surgery. We generated binary classifiers using support vector machine (SVM) and conventional linear models for predicting perioperative cardiac events. We used clinical and surgical risk, and SPECT findings as input data, and the occurrence of all and hard cardiac events as output data. The area under the receiver-operating characteristic curve (AUC) was calculated for assessing the prediction accuracy. The AUC values were 0.884 and 0.748 in the SVM and linear models, respectively in predicting all cardiac events with clinical and surgical risk, and SPECT variables. The values were 0.861 (SVM) and 0.677 (linear) when not using SPECT data as input. In hard events, the AUC values were 0.892 (SVM) and 0.864 (linear) with SPECT, and 0.867 (SVM) and 0.768 (linear) without SPECT.
  
  
  CONCLUSIONS
  The SVM was superior to the linear model in risk stratification. We also found an incremental prognostic value of SPECT results over information about clinical and surgical risk.
authors.affiliation: Department of Radiology, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan. kasa76@yahoo.co.jp
authors.forename: Tomotaka
authors.initials: T
authors.lastname: Kasamatsu
authors.forename: Jun
authors.initials: J
authors.lastname: Hashimoto
authors.forename: Hitoshi
authors.initials: H
authors.lastname: Iyatomi
authors.forename: Tadaki
authors.initials: T
authors.lastname: Nakahara
authors.forename: Jingming
authors.initials: J
authors.lastname: Bai
authors.forename: Naoto
authors.initials: N
authors.lastname: Kitamura
authors.forename: Koichi
authors.initials: K
authors.lastname: Ogawa
authors.forename: Atsushi
authors.initials: A
authors.lastname: Kubo
mesh_terms: D000368:Aged; D015331:Cohort Studies; D005260:Female; D006331:Heart Diseases / Q000601:surgery*; D006801:Humans; D008297:Male; D008962:Models, Theoretical; D055414:Myocardial Perfusion Imaging; D011300:Preoperative Care; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D015899:Tomography, Emission-Computed, Single-Photon