Table 2

Reasons for Missing or Technically Inadequate NIRS Data in the SPECTACL Study Population

No. of Patients (n = 36)
Missing data
 Inability to track vessel with IVUS or NIRS catheter7
 Lack of signal from NIRS catheter4
 Console setup error2
 Jammed PBR1
 Improperly assembled accessory1
 Improper catheter handling1
 Incomplete catheter connection1
Technically inadequate data
 Instrumental causes
   Obstructions: guide wire, guide catheter, stent, bubbles in saline of primed catheters5
   Poor connection between catheter and PBR4
   Microscopic debris on optical fiber faces2
   Damaged optical fibers1
   System malfunction1
 Biological causes
   Features causing disturbances in blood flow: sudden changes in lumen diameter or orientation, side-branches, thrombi5
   Excessive blood depth in large arteries1

IVUS = intravascular ultrasound; NIRS = near-infrared spectroscopy; PBR = pullback and rotation; SPECTACL = SPECTroscopic Assessment of Coronary Lipid trial.