Comparison of myocardial fractional flow reserve and intravascular ultrasound for the assessment of slotted-tube stents.

Intravascular ultrasound (IVUS) and myocardial fractional flow reserve (FFR) have been reported to provide similar results for assessment of coil stent deployment. Their relative value in slotted-tube stents has not been investigated. Fourteen patients subjected to coronary angioplasty and IVUS-guided elective stenting with a slotted-tube stent underwent IVUS assessment and FFR measurement following stent implantation at inflation pressures of 12 and 18 atm. FFR values (mean +/- SD) preangioplasty, postangioplasty, and poststenting at 12 atm and 18 atm, were 0.58 +/- 0.07, 0.83 +/- 0.05, 0.94 +/- 0.02, and 0.94 +/- 0.02, respectively. After inflation at 12 atm, the area under the receiver operating characteristic (ROC) curve for the concordance of IVUS and FFR measurements was 0.89 (P = 0.02). Six patients had either an abnormal IVUS (n = 2) or FFR < 0.94 (n = 1) or both abnormal IVUS and FFR < 0.94 (n = 3) after the first inflation and had a second inflation at 18 atm. The area under the ROC curve for the concordance between IVUS and FFR final measurements was 0.855 (P = 0.10). Perfect concordance between IVUS and FFR was seen only for FFR values less than 0.91 or larger than 0.94. Overall, IVUS and FFR have substantial concordance with respect to slotted-tube stent deployment. However, FFR values between 0.91 and 0.94 after inflation are difficult to interpret.