Diagnostic accuracy of intracoronary optical coherence tomography-derived fractional flow reserve for assessment of coronary stenosis severity.

AIMS: A novel method for computation of fractional flow reserve (FFR) from optical coherence tomography (OCT) was developed recently. This study aimed to evaluate the diagnostic accuracy of a new OCT-based FFR (OFR) computational approach, using wire-based FFR as the reference standard. METHODS AND RESULTS: Patients who underwent both OCT and FFR prior to intervention were analysed. The lumen of the interrogated vessel and the ostia of the side branches were automatically delineated and used to compute OFR. Bifurcation fractal laws were applied to correct the change in reference lumen size due to the step-down phenomenon. OFR was compared with FFR, both using a cut-off value of 0.80 to define ischaemia. Computational analysis was performed in 125 vessels from 118 patients. Average FFR was 0.80±0.09. Accuracy, sensitivity, specificity, positive predictive value, and negative predictive value for OFR to identify FFR ≤0.80 was 90% (95% CI: 84-95), 87% (95% CI: 77-94), 92% (95% CI: 82-97), 92% (95% CI: 82-97), and 88% (95% CI: 77-95), respectively. The AUC was higher for OFR than minimal lumen area (0.93 [95% CI: 0.87-0.97] versus 0.80 [95% CI: 0.72-0.86], p=0.002). Average OFR analysis time was 55±23 seconds for each OCT pullback. Intra- and inter-observer variability in OFR analysis was 0.00±0.02 and 0.00±0.03, respectively. CONCLUSIONS: OFR is a novel and fast method allowing assessment of flow-limiting coronary stenosis without pressure wire and induced hyperaemia. The good diagnostic accuracy and low observer variability bear the potential of improved integration of intracoronary imaging and physiological assessment.

Comparison of two and three dimensional quantitative coronary angiography to intravascular ultrasound in the assessment of left main coronary artery bifurcation lesions.

BACKGROUND: Angiographic evaluation of left main coronary artery (LMCA) bifurcation lesions is often limited. two dimensional (2D) quantitative coronary angiography (QCA) with segmental analysis provides accuracy for quantification of the degree of stenosis in the main vessel and side branch ostium but can be affected by foreshortening and variable magnification. The accuracy of three dimensional (3D) QCA has recently developed to overcome 2D QCA limitations, however, accuracy and precision of 3D bifurcation QCA measurements in LMCA bifurcation lesions has not been established. METHODS: We investigated whether such 3D and 2D bifurcation QCA measurements differ in their accuracy in assessing significant LMCA bifurcation lesions defined by intravascular ultrasound (IVUS) as a minimum luminal area (MLA) <6 mm(2) of LMCA and MLA <4 mm(2) of proximal left anterior descending (LAD) and/or proximal left circumflex (LCX) RESULTS: LMCA bifurcation lesions were assessed in 44 patients undergoing elective percutaneous coronary intervention. From 2D QCA measurements, MLA correlated moderately with threshold intravascular ultrasound MLA for LMCA (r = 0.81, P < 0.000 1), LAD (r = 0.54, P = 0.000 1) and LCX (r = 0.58, P < 0.000 1). Severity of lesion as MLA by derived 3D QCA, correlated moderately with threshold intravascular ultrasound MLA for LMCA (r = 0.84, P < 0.000 1), LAD (r = 0.53, P = 0.000 2); LCX (r = 0.66, P < 0.000 1). Overall, the C statistics tended to be slightly higher for 3D QCA and 2D QCA measurements in LMCA segment compared with proximal LAD and LCX segments, and there were no significant predictive power of percent diameter stenosis and percent area stenosis on 3D QCA for LCX IVUS MLA <4 mm(2) (percent diameter stenosis: area under curve 0.55, cutoff 23%, sensitivity 88%, specificity 37%, P = 0.618 6; percent arer stenosis: area under curve 0.56, cutoff 41%, sensitivity 83%, specificity 38%, P = 0.518 4, respectively). CONCLUSIONS: The accuracy of 3D bifurcation QCA in detecting significant LMCA bifurcation lesions is limited, especially the proximal LCX ostium. When IVUS is not available or contraindicated, 3D QCA may assist in the evaluation of intermediate LMCA lesions with MLA.

Quantitative assessment of late lumen loss after biodegradable polymer and permanent polymer sirolimus-eluting stents implantation.

BACKGROUND: Sirolimus-eluting stents (SES) are reported to be associated with reduced late lumen loss (LLL), resulting in less frequent restenosis when compared to bare-metal stent. The current study aimed to assess the difference in LLL between SES with biodegradable and with permanent polymer. METHODS: From March 2010 to June 2011, 300 consecutive patients having only biodegradable polymers or permanent polymer SES for all diseased vessels were included. Serial quantitative coronary analysis was performed on both the "in-stent" and "segment" area, including the stented segment, as well as both five mm margins proximal and distal to the stent. The primary endpoint was the LLL defined as the minimal lumen diameter (MLD) post-stenting minus the MLD at nine-month after the indexed procedure. RESULTS: LLL was comparable between the two stents. Importantly, LLL for the distal segment (median 0.05 mm, interquartile 0 to 0.09 mm) was less severe compared with in-stent (median 0.13 mm, interquartile 0.08 to 0.18 mm) and proximal segment LLL (median 0.12 mm, interquartile 0.06 to 0.14 mm, all P < 0.001). In general, the LLL was associated with the post-procedure MLD (b = 0.28, P = 0.002), hyperlipidemia (b = 0.14, P = 0.021), and calcified lesions (b = 0.58, P = 0.001). The R(2) and Radj of the multiple regression model were 0.651 and 0.625, respectively. CONCLUSIONS: SES with either biodegradable or permanent polymer had lower value of LLL. The small amount of LLL at the distal segment possibly contributed to the less distal edge stenosis.

Comparison between the NERS (New Risk Stratification) score and the SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) score in outcome prediction for unprotected left main stenting.

OBJECTIVES: This study aimed to compare the NERS (New Risk Stratification) and SYNTAX (Synergy between Percutaneous Coronary Intervention with Taxus and Cardiac Surgery) scores for prognostication after stenting of unprotected left main stenosis in a "real-world" setting. BACKGROUND: In contrast to existing systems, the NERS score encompasses clinical, procedural, and angiographic characteristics. METHODS: The NERS score was derived from 260 patients with unprotected left main stenosis who underwent percutaneous coronary intervention and tested in 337 patients in a consecutive left main registry (66.55 +/- 10.49 years, 78.9% men) undergoing percutaneous coronary intervention in a prospective, multicenter trial. Six-month clinical and angiographic follow-up was obtained in 100% and 88.9% of patients, respectively. The primary end point was major adverse cardiac events (MACE), encompassing myocardial infarction, all-cause death, and target vessel revascularization. Receiver-operator characteristic (ROC) curve was generated for the comparison of NERS versus SYNTAX scores. RESULTS: The NERS score consisted of 54 variables (17 clinical, 4 procedural, and 33 angiographic). A NERS score > or =25 demonstrated a sensitivity and specificity of 92.0% and 74.1% (MACE as state variable), respectively, significantly higher than SYNTAX intermediate risk (20.5% and 25.4%) or SYNTAX higher risk (70.5% and 35.2%, p for all <0.001). At follow-up, myocardial infarction, cardiac death, and target vessel revascularization occurred in 3.0%, 5.6%, and 13.1% of patients, respectively, for a composite MACE of 26.0%. A NERS score > or =25 (hazard ratio: 1.13; 95% confidence interval [CI]: 1.11 to 1.16; p < 0.001) was the only independent predictor of cumulative MACE and stent thrombosis at follow-up (odds ratio: 31.04; 95% CI: 19.36 to 67.07; p < 0.001). CONCLUSIONS: The NERS score was more predictive of MACE than the SYNTAX score was. Further study is needed to address their relative roles in assessment for appropriateness of coronary artery bypass graft versus percutaneous coronary intervention for unprotected left main coronary artery stenosis.