Effect of contrast medium versus low-molecular-weight dextran for intracoronary optical coherence tomography in renal insufficiency.

Low-molecular-weight dextran (LMWD) is considered a safe alternative to contrast media to displace blood during optical coherence tomography (OCT) imaging, but concerns remain. The purpose of this study was to investigate whether using LMWD for OCT protects against kidney injury in patients with renal insufficiency compared with contrast media. We retrospectively identified 474 patients with renal insufficiency (estimated glomerular filtration rate < 60 ml/min/1.73 m2) who underwent OCT during coronary angiography or percutaneous coronary intervention; 110 patients with LMWD plus contrast medium (LMWD group) and 364 patients with contrast medium exclusively (Contrast group). We evaluated differences between the two groups and performed propensity score-matched subgroup comparisons. Compared with the Contrast group, the LMWD group had worse baseline renal function, higher prevalence of diabetes mellitus and percutaneous coronary intervention history, higher C-reactive protein and N-terminal pro B-type natriuretic peptide levels, lower hemoglobin levels, and lower left ventricular ejection fraction. The median total volume of contrast medium in the Contrast group was 230.0 ml vs. 61.8 ml of LMWD in addition to 164.0 ml of contrast medium in the LMWD group. Renal function was consistently impaired in the LMWD group within 5 days, at 1-month, and 1-year follow-up (P < 0.001). Two propensity score-matched analyses adjusted for either total volume used or contrast media volume consistently indicated a trend toward worsening renal function in the LMWD group at the 1-year follow-up. No protective benefit for renal function from using LMWD instead of contrast media for OCT was observed in patients with renal insufficiency.

Ventricular Fibrillation During Optical Coherence Tomography/Optical Frequency Domain Imaging　- A Large Single-Center Experience.

BACKGROUND: The risks of ventricular fibrillation (Vfib) associated with frequency-domain optical coherence tomography (OCT)/optical frequency domain imaging (OFDI) remain undetermined.Methods and Results:We retrospectively studied the occurrence of Vfib during OCT/OFDI for unselected indications. The frequency of Vfib and patient and procedural characteristics were investigated. A total of 4,467 OCT/OFDI pullback examinations were performed in 1,754 patients (median of 2.0 [2.0-3.0] pullbacks for 1.0 [1.0-1.3] vessels). OCT/OFDI was performed during PCI in 899 patients (51.3%). The contrast injection volume per pullback was 14.4 (11.7-17.2) mL with a flow rate of 3.4 (3.2-3.5) mL/s. Vfib occurred in 31 pullbacks (0.69%) in 30 patients (1.7%). No cases of Vfib occurred when using low-molecular-weight dextran. On multivariate analysis, contrast volume was the only independent factor for predicting Vfib (odds ratio, 1.080; 95% confidence interval, 1.008-1.158, P=0.029). The best cutoff value of contrast volume for predicting Vfib was 19.2 mL (area under the curve, 0.713, P<0.001; diagnostic accuracy, 87.1%). CONCLUSIONS: The present large, single-center registry study indicated that Vfib during OCT/OFDI was rare for unselected indications. Contrast injection volume used to displace blood should be limited to avoid Vfib.

Impact of Pressure Signal Drift on Fractional Flow Reserve-Based Decision-Making for Patients With Intermediate Coronary Artery Stenosis.

BACKGROUND: Fractional flow reserve (FFR) is an important physiological measure of intermediate coronary artery stenosis. Pressure signal drift (PD) is widely recognized but has largely been ignored in FFR measurements. We sought to determine the effect of PD on FFR-derived decision-making. METHODS AND RESULTS: We analyzed 1,218 FFR measurements for intermediate stenosis in 940 patients, in which the pullback maneuver confirmed PD ≤3 mmHg. The primary objectives were to determine the frequency and magnitude of PD and its effect on decision-making on the basis of an FFR cutoff of 0.80. In all, 479 (39.3%) measurements showed PD. PD was significantly associated with age, hypertension, reference diameter, left anterior descending artery lesion location, and read-out FFR values. Classification discordance between read-out and PD-corrected FFR values was detected in 44 (3.6%) measurements in total and in 9.2% of PD cases. The decision changed from FFR ≤0.80 to FFR >0.80 in 40 (3.3%) and vice versa in 4 (0.3%) measurements. PD showed no effect on decision-making when the FFR read-out value was ≤0.76 or ≥0.83. CONCLUSIONS: PD is not uncommon, and its effect on FFR-based decision-making was not negligible in the range between 0.77 and 0.82 where reclassification occurred in 18.7% of FFR measurements. (Circ J 2016; 80: 1812-1819).