title: Neural network pattern recognition analysis of graft flow characteristics improves intra-operative anastomotic error detection in minimally invasive CABG.
abstract: OBJECTIVE
  The intra-operative assessment of the quality of anastomosis in minimally invasive coronary artery bypass surgery (CABG) is critical. Recent investigations demonstrated that flow probes used intra-operatively to assess anastomotic errors may give the surgeon a false sense of confidence as only severely stenotic anastomoses (>90%) could be reliably detected. We developed a neural network system using graft flow data and assessed its potential to improve anastomotic error detection.
  
  
  METHODS
  Mammary to LAD grafts (n = 46) were constructed in mongrel dogs off-pump. Continuous beat-to-beat graft flow was recorded using transit-time flow probes. Various degrees of anastomotic stenoses (0-100%) were created by an additional suture. The degree of anastomotic stenosis was confirmed by postoperative angiography. A learning vector quantization neural network was created using heart rate, mean aortic pressure, mean systolic, maximum systolic, minimum systolic, mean diastolic, maximum diastolic, minimum diastolic, and mean graft flows. In addition, a spectral analysis of the flow waveforms was performed and the magnitude and phase of the first five harmonics were used to further develop the neural network.
  
  
  RESULTS
  The neural network pattern recognition system was 94% accurate in detecting any stenosis >50%. To validate the model, a testing set was used with 20% of the data values, and the accuracy remained at 100% above chance alone.
  
  
  CONCLUSIONS
  Pattern recognition of transit-time flow probe tracings using neural network systems can detect anastomotic errors significantly better than the surgeon's visual assessment, thereby improving the clinical outcome of minimally invasive CABG.
authors.affiliation: Jewish Hospital Cardiothoracic Surgical Research Institute at the University of Louisville, Department of Surgery, University of Louisville, School of Medicine, KY 40202, USA.
authors.forename: P B
authors.initials: PB
authors.lastname: Cerrito
authors.forename: S C
authors.initials: SC
authors.lastname: Koenig
authors.forename: D J
authors.initials: DJ
authors.lastname: VanHimbergen
authors.forename: S F
authors.initials: SF
authors.lastname: Jaber
authors.forename: D L
authors.initials: DL
authors.lastname: Ewert
authors.forename: P A
authors.initials: PA
authors.lastname: Spence
mesh_terms: D000714:Anastomosis, Surgical; D000818:Animals; D001026:Coronary Artery Bypass / Q000379:methods*; D004285:Dogs; D005583:Fourier Analysis; D006801:Humans; D007432:Intraoperative Period; D019060:Minimally Invasive Surgical Procedures; D016571:Neural Networks, Computer; D011237:Predictive Value of Tests; D012372:ROC Curve; D012039:Regional Blood Flow; D016896:Treatment Outcome