Assessment of the renal angina index in patients hospitalized in a cardiac intensive care unit.

The renal angina index (RAI) is a validated scoring tool for predicting acute kidney injury (AKI). We investigated the efficacy of the RAI in 2436 heterogeneous patients (mean age, 70 years) treated in cardiac intensive care units (CICUs). The RAI was calculated from creatinine and patient condition scores. AKI was diagnosed by the Kidney Disease: Improving Global Outcome criteria. The primary and secondary endpoints were the development of severe AKI and all-cause mortality, respectively. Four hundred thirty-three patients developed AKI, 87 of them severe. In multivariate analyses, the RAI was a significant independent predictor of severe AKI. During the 12-month follow-up period, 210 patients suffered all-cause death. Elevated RAI was independently associated with all-cause mortality, as was NT-proBNP (p < 0.001). The RAI is a potent predictor not only of severe AKI but also of adverse outcomes and substantially improved the 12-month risk stratification of patients hospitalized in CICUs.

Preprocedural physiological assessment of coronary disease patterns to predict haemodynamic outcomes post-PCI.

BACKGROUND: Even with intracoronary imaging-guided stent optimisation, suboptimal haemodynamic outcomes post-percutaneous coronary intervention (PCI) can be related to residual lesions in non-stented segments. Preprocedural assessment of pathophysiological coronary artery disease (CAD) patterns could help predict the physiological response to PCI. AIMS: The aim of this study was to assess the relationship between preprocedural pathophysiological haemodynamic patterns and intracoronary imaging findings, as well as their association with physiological outcomes immediately post-PCI. METHODS: Data from 206 patients with chronic coronary syndrome enrolled in the ASET-JAPAN study were analysed. Pathophysiological CAD patterns were characterised using Murray law-based quantitative flow ratio (µQFR)-derived indices acquired from pre-PCI angiograms. The diffuseness of CAD was defined by the pullback pressure gradient (PPG) index. Intracoronary imaging in stented segments after stent optimisation was also analysed. RESULTS: In the multivariable analysis, diffuse disease - defined by the pre-PCI µQFR-PPG index - was an independent factor for predicting a post-PCI µQFR <0.91 (per 0.1 decrease of PPG index, odds ratio 1.57, 95% confidence interval: 1.07-2.34; p=0.022), whereas the stent expansion index (EI) was not associated with a suboptimal post-PCI µQFR. Among vessels with an EI ≥80% and post-PCI µQFR <0.91, 84.0% of those vessels had a diffuse pattern preprocedure. There was no significant difference in EI between vessels with diffuse disease and those with focal disease. The average plaque burden in the stented segment was significantly larger in vessels with a preprocedural diffuse CAD pattern. CONCLUSIONS: A physiological diffuse pattern preprocedure was an independent factor in predicting unfavourable immediate haemodynamic outcomes post-PCI, even after stent optimisation using intracoronary imaging. Preprocedural assessment of CAD patterns could identify patients who are likely to exhibit superior immediate haemodynamic outcomes following PCI.

FRAX assessment in people ageing with HIV.

OBJECTIVES: Current British HIV Association (BHIVA) guidelines recommend the use of FRAX for the routine assessment of bone fracture risk in people living with HIV over 50 years of age every 3 years. Bone mineral density measurement with dual-energy X-ray absorptiometry (DXA) scan is recommended for those with increased fracture risk (FRAX major > 10%). Our objectives were to estimate the prevalence of and risk factors for osteoporosis in a population of PLWH aged > 50 years and assess the utility of FRAX in predicting the presence of DXA-proven osteoporosis in this cohort. METHODS: This was a cross-sectional study of a cohort of PLWH aged > 50 years attending the Chelsea and Westminster Hospital and who had a DXA scan between January 2009 and December 2018. FRAX scores were calculated using the Sheffield algorithm. Multiple regression models and Cohen's kappa values were used to assess risk factors for osteoporosis and agreement between FRAX and DXA scan results, respectively. RESULTS: In all, 744 patients were included (92.9% male, mean age 56 ± 5 years). The prevalence rates of osteoporosis (at DXA scans) and osteopenia were 12.2% and 63.7%, respectively. FRAX major was > 10% in only two patients, while 90/91 (98.9%) patients with osteoporosis had a normal FRAX score. The presence of osteoporosis was significantly associated with low body mass index and estimated glomerular filtration rate (p < 0.05). CONCLUSION: Our results indicate that FRAX scores did not predict the presence of osteoporosis in our population of PLWH over 50 years of age and therefore FRAX scores may not be the appropriate tool to define eligibility to perform DXA scans in PLWH.

Combined Assessment of D-Dimer with the Get with the Guidelines-Heart Failure Risk Score and N-Terminal Pro-B-Type Natriuretic Peptide in Patients with Acute Decompensated Heart Failure with Preserved and Reduced Ejection Fraction.

The prognostic role of D-dimer in different types of heart failure (HF) is poorly understood. We investigated the prognostic value of D-dimer on admission, both independently and in combination with the Get With The Guidelines-Heart Failure (GWTG-HF) risk score and N-terminal pro-B-type natriuretic peptide (NT-proBNP), in patients with preserved left ventricular ejection fraction (LVEF) and acute decompensated HF (HFpEF) or reduced LVEF (HFrEF). Baseline D-dimer levels were measured on admission in 1670 patients (mean age: 75 years) who were hospitalized for worsening HF. Of those patients, 586 (35%) were categorized as HFpEF (LVEF ≥ 50%) and 1084 as HFrEF (LVEF < 50%). During the 12-month follow-up period after admission, 360 patients died. Elevated levels (at least the highest tertile value) of D-dimer, GWTG-HF risk score, and NT-proBNP were all independently associated with mortality in all HFpEF and HFrEF patients (all p < 0.05). Adding D-dimer to a baseline model with a GWTG-HF risk score and NT-proBNP improved the net reclassification and integrated discrimination improvement for mortality greater than the baseline model alone in all populations (all p < 0.001). The number of elevations in D-dimer, GWTG-HF risk score, and NT-proBNP were independently associated with a higher risk of mortality in all study populations (HFpEF and HFrEF patients; all p < 0.001). The combination of D-dimer, which is independently predictive of mortality, with the GWTG-HF risk score and NT-proBNP could improve early prediction of 12-month mortality in patients with acute decompensated HF, regardless of the HF phenotype.

On-site assessment of computed tomography-derived fractional flow reserve in comparison with myocardial perfusion imaging and invasive fractional flow reserve.

Myocardial perfusion imaging (MPI) using Single Photon Emission Computed Tomography has been established as a standard noninvasive tool for risk stratification of coronary artery disease (CAD). We evaluated the diagnostic performance of on-site workstation-based computed tomography-derived fractional flow reserve (CT-FFR) in comparison with MPI using invasive fractional flow reserve (invasive FFR) as a gold standard. We enrolled 97 patients with suspected CAD. Diagnostic performance of CT angiography (CTA), and CT-FFR was compared in 105 lesions of 97 patients. Invasive FFR ≤ 0.8 was detected in 38 (36%) lesions. Diagnostic performance of CT-FFR was improved compared with CTA (AUC 0.83 vs. 0.60, p < 0.0001). The lesions with both CTA and MPI findings (n = 47), invasive FFR ≤ 0.8 was detected in 19 (40.4) lesions. CT-FFR (AUC 0.81, 95% CI 0.72-0.94) significantly improved diagnostic performance compared with CTA-50% (AUC 0.59, p = 0.00019) and MPI (AUC 0.64, p = 0.0082). In lesions with ≥ 50% on CTA (n = 42), diagnostic accuracy of CT-FFR (AUC 0.81) was significantly superior to MPI (AUC 0.64, p = 0.0239). In conclusions, CT-FFR improved diagnostic accuracy to detect invasive FFR ≤ 0.8 compared with luminal stenosis on CTA and ischemia on MPI. Patients with ≥ 50% stenosis on CTA would be the candidates for CT-FFR.

Serial volumetric assessment of coronary fibroatheroma by optical frequency domain imaging: insights from the TROFI trial.

Aims: Coronary lesions precursors of acute events remain elusive, since they undergo continuous changes and their temporal changes are not very well-characterized. In natural history studies, optical frequency domain imaging (OFDI) has been used only to assess fibroatheromas as a 2D structure and sometimes in a single frame fashion. We aim at describing the serial volumetric modifications of the fibrous cap (FC) of the fibroatheromas as determined by OFDI over a 6-month follow-up period. Methods and results: In 49 patients, OFDI investigation was performed following treatment of culprit lesion and at 6-month follow-up in patients with ST-segment elevation myocardial infarction (STEMI). A fully automatic volumetric quantification of FC was done in all lipid-containing frames of non-culprit lesions in the infarct related artery. These lesions were matched at baseline and 6-month follow-up. A total of 58 non-culprit lipid rich lesions (34 TCFAs and 24 thick-cap fibroatheroma [ThCFA]) were found in 34 patients at baseline. Overall, there was a FC volume decrease of 1.57 (Inter-quartile Range [IQR] -4.13 to 0.54) mm3 at 6-months. 27% of the lesions changed their phenotype over time (TCFA or ThCFA). TCFAs that became ThCFAs at follow-up had smaller mean and maximal FC as compared with lesions that remained TCFAs (P = 0.01 for both). Conclusions: Non-culprit fibroatheromas located in the infarct related artery of patients with STEMI had a volumetric reduction of the FC after 6-month follow-up. Quantitative FC assessment was able to differentiate high-risk lesions that became ThCFAs. There was a considerable change of plaque phenotype (TCFAs or ThCFAs) over time.

Imaging assessment of bioresorbable vascular scaffolds.

Vascular reparative therapy has become a reality with bioresorbable scaffolds (BRSs). To assess acute and long-term performance of the device, multimodality imaging would be essential. Radiopacity of metal hinders the imaging assessment, whereas radiolucent polymeric scaffolds allow for a precise imaging assessment with either invasive or non-invasive modality at baseline and at follow-up, which is one of the advantages of polymeric BRSs. Recent large trials evaluating clinical results of the first-generation BRS technology raised concerns about the safety and efficacy of these devices, namely, scaffold thrombosis. Intensive research with multimodality imaging in the field is being conducted to have in-depth understanding of the issues, which will facilitate the improvement of implantation techniques and the development of the next-generation BRSs. The current review focuses on the clinical application of the imaging modalities to assess the short- and long-term performance of the Absorb BVS.

Assessment of trough rivaroxaban concentrations on markers of coagulation activation in nonvalvular atrial fibrillation population.

Whether trough-phase rivaroxaban concentrations provide sufficient anticoagulation needs more study. We evaluated levels of coagulation activation markers in the trough concentration phase in nonvalvular atrial fibrillation (NVAF) patients, and the correlation between these markers and rivaroxaban concentration. Fifty-five Japanese NVAF patients received 24-week rivaroxaban treatment of either 15 or 10 mg once-daily in the morning. Of these, 26 patients had no history of anticoagulant therapy (naive group) and 29 had switched from warfarin (warfarin group). D-dimer and prothrombin fragment 1 + 2 (F1 + 2) levels, and protein C activities were measured at 0 (baseline), 12 and 24 weeks of rivaroxaban treatment just before the patient's regular dosing time (trough phase). For 49 patients, D-dimer, F1 + 2, and rivaroxaban concentrations were also measured twice between 28 and 32 weeks of rivaroxaban treatment at non-trough times to achieve a range of drug concentrations for correlation analysis. For the naive group, D-dimer and F1 + 2 levels were significantly reduced (p < 0.01) from baseline at 12 and 24 weeks. For the warfarin group, these values were unchanged for D-dimer but significantly increased (p < 0.01) for F1 + 2. Protein C activity was unchanged in the naive group and was increased (p < 0.01) in the warfarin group. Prothrombin time (r = 0.92, p < 0.0001) and activated partial thromboplastin time (r = 0.54, p < 0.0001) correlated with rivaroxaban concentration, but not D-dimer and F1 + 2 levels. In conclusion, rivaroxaban in the trough phase is comparable to warfarin in reducing D-dimer levels. Although trough level rivaroxaban suppresses F1 + 2 less than warfarin, the higher activities of protein C with rivaroxaban treatment compared to warfarin treatment may counterbalance this. Lack of correlation between rivaroxaban concentration and D-dimer and F1 + 2 levels suggests that trough concentrations of rivaroxaban reduce their concentrations as effectively as higher levels do.

Assessment of endothelial shear stress in patients with mild or intermediate coronary stenoses using coronary computed tomography angiography: comparison with invasive coronary angiography.

Characterization of endothelial shear stress (ESS) may allow for prediction of the progression of atherosclerosis. The aim of this investigation was to develop a non-invasive approach for in vivo assessment of ESS by coronary computed tomography angiography (CTA) and to compare it with ESS derived from invasive coronary angiography (ICA). A total of 41 patients with mild or intermediate coronary stenoses who underwent both CTA and ICA were included in the analysis. Two geometrical models of the interrogated vessels were reconstructed separately from CTA and ICA images. Subsequently, computational fluid dynamics were applied to calculate the ESS, from which ESSCTA and ESSICA were derived, respectively. Comparisons between ESSCTA and ESSICA were performed on 163 segments of 57 vessels in the CTA and ICA models. ESSCTA and ESSICA were similar: mean ESS: 4.97 (4.37-5.57) Pascal versus 4.86 (4.27-5.44) Pascal, p = 0.58; minimal ESS: 0.86 (0.67-1.05) Pascal versus 0.79 (0.63-0.95) Pascal, p = 0.37; and maximal ESS: 14.50 (12.62-16.38) Pascal versus 13.76 (11.44-16.08) Pascal, p = 0.44. Good correlations between the ESSCTA and the ESSICA were observed for the mean (r = 0.75, p < 0.001), minimal (r = 0.61, p < 0.001), and maximal (r = 0.62, p < 0.001) ESS values. In conclusion, geometrical reconstruction by CTA yields similar results to ICA in terms of segment-based ESS calculation in patients with low and intermediate stenoses. Thus, it has the potential of allowing combined local hemodynamic and plaque morphologic information for risk stratification in patients with coronary artery disease.

Comparison between two- and three-dimensional quantitative coronary angiography bifurcation analyses for the assessment of bifurcation lesions: A subanalysis of the TRYTON pivotal IDE coronary bifurcation trial.

BACKGROUND: Three-dimensional (3D) quantitative coronary angiography (QCA) provides more accurate measurements by minimizing inherent limitations of two-dimensional (2D) QCA. The aim of this study was to compare the measurements between 2D and 3D QCA analyses in bifurcation lesions. METHODS AND RESULTS: A total of 114 cases with non-left main bifurcation lesions in the TRYTON pivotal IDE Coronary Bifurcation Trial (ClinicalTrials.gov: NCT01258972) were analyzed using a validated bifurcation QCA software (CAAS 5.10, Pie Medical Imaging, Maastricht, the Netherlands). All cases were analyzed in matched projections between pre- and post-procedure. The 2D analysis was performed using one of two angiographic images used for 3D reconstruction showing a larger distal bifurcation angle. In the treated segments (stent and balloon), there were no differences in minimal luminal diameter (MLD) between 2D and 3D, while diameter stenosis (DS) was significantly higher in 2D compared to 3D both pre-procedure and post-procedure (53.9% for 2D vs. 52.1% for 3D pre-procedure, P < 0.01; 23.2% for 2D vs. 20.9% for 3D post-procedure, P = 0.01). In the sub-segment level analysis, lengths of proximal main branch, distal main branch, and side branch were consistently shorter in 2D compared to 3D both pre-procedure and post-procedure. Using 3D QCA, the anatomic location of the smallest MLD or the highest DS was relocated to a different bifurcation sub-segment in a considerable proportion of the patients compared to when 2D-QCA was used (kappa values: 0.50 for MLD, 0.55 for DS). CONCLUSIONS: Our data showed differences in addressing anatomical severity and location of coronary bifurcation lesions between in vivo 2D and 3D QCA analyses. More studies are needed to investigate potential clinical benefits in using 3D approach over 2D QCA for the assessment of bifurcation lesions.

Incidence and imaging outcomes of acute scaffold disruption and late structural discontinuity after implantation of the absorb Everolimus-Eluting fully bioresorbable vascular scaffold: optical coherence tomography assessment in the ABSORB cohort B Trial (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions).

OBJECTIVES: This study sought to describe the frequency and clinical impact of acute scaffold disruption and late strut discontinuity of the second-generation Absorb bioresorbable polymeric vascular scaffolds (Absorb BVS, Abbott Vascular, Santa Clara, California) in the ABSORB (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions) cohort B study by optical coherence tomography (OCT) post-procedure and at 6, 12, 24, and 36 months. BACKGROUND: Fully bioresorbable scaffolds are a novel approach to treatment for coronary narrowing that provides transient vessel support with drug delivery capability without the long-term limitations of metallic drug-eluting stents. However, a potential drawback of the bioresorbable scaffold is the potential for disruption of the strut network when overexpanded. Conversely, the structural discontinuity of the polymeric struts at a late stage is a biologically programmed fate of the scaffold during the course of bioresorption. METHODS: The ABSORB cohort B trial is a multicenter single-arm trial assessing the safety and performance of the Absorb BVS in the treatment of 101 patients with de novo native coronary artery lesions. The current analysis included 51 patients with 143 OCT pullbacks who underwent OCT at baseline and follow-up. The presence of acute disruption or late discontinuities was diagnosed by the presence on OCT of stacked, overhung struts or isolated intraluminal struts disconnected from the expected circularity of the device. RESULTS: Of 51 patients with OCT imaging post-procedure, acute scaffold disruption was observed in 2 patients (3.9%), which could be related to overexpansion of the scaffold at the time of implantation. One patient had a target lesion revascularization that was presumably related to the disruption. Of 49 patients without acute disruption, late discontinuities were observed in 21 patients. There were no major adverse cardiac events associated with this finding except for 1 patient who had a non-ischemia-driven target lesion revascularization. CONCLUSIONS: Acute scaffold disruption is a rare iatrogenic phenomenon that has been anecdotally associated with anginal symptoms, whereas late strut discontinuity is observed in approximately 40% of patients and could be viewed as a serendipitous OCT finding of a normal bioresorption process without clinical implications. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856).

Fast virtual functional assessment of intermediate coronary lesions using routine angiographic data and blood flow simulation in humans: comparison with pressure wire - fractional flow reserve.

AIMS: To develop a simplified approach of virtual functional assessment of coronary stenosis from routine angiographic data and test it against fractional flow reserve using a pressure wire (wire-FFR). METHODS AND RESULTS: Three-dimensional quantitative coronary angiography (3D-QCA) was performed in 139 vessels (120 patients) with intermediate lesions assessed by wire-FFR (reference standard: ≤0.80). The 3D-QCA models were processed with computational fluid dynamics (CFD) to calculate the lesion-specific pressure gradient (ΔP) and construct the ΔP-flow curve, from which the virtual functional assessment index (vFAI) was derived. The discriminatory power of vFAI for ischaemia- producing lesions was high (area under the receiver operator characteristic curve [AUC]: 92% [95% CI: 86-96%]). Diagnostic accuracy, sensitivity and specificity for the optimal vFAI cut-point (≤0.82) were 88%, 90% and 86%, respectively. Virtual-FAI demonstrated superior discrimination against 3D-QCA-derived % area stenosis (AUC: 78% [95% CI: 70- 84%]; p<0.0001 compared to vFAI). There was a close correlation (r=0.78, p<0.0001) and agreement of vFAI compared to wire-FFR (mean difference: -0.0039±0.085, p=0.59). CONCLUSIONS: We developed a fast and simple CFD-powered virtual haemodynamic assessment model using only routine angiography and without requiring any invasive physiology measurements/hyperaemia induction. Virtual-FAI showed a high diagnostic performance and incremental value to QCA for predicting wire-FFR; this "less invasive" approach could have important implications for patient management and cost.

Assessment of plaque evolution in coronary bifurcations located beyond everolimus eluting scaffolds: serial intravascular ultrasound virtual histology study.

PURPOSE: To evaluate the atherosclerotic evolution in coronary bifurcations located proximally and distally to a bioresorbable scaffold. METHODS: Thirty bifurcations located >5 mm beyond the scaffolded segment, being investigated with serial intravascular ultrasound virtual histology (IVUS-VH) examinations, at baseline and 2-years, in patients enrolled in the ABSORB cohort B1 study were included in this analysis. In each bifurcation, the frames portraying the proximal rim, in-bifurcation, and distal rim of the ostium of the side branch were analyzed. The geometric parameters and plaque types were evaluated at baseline and 2-years follow-up. RESULTS: There were no significant differences in the geometrical parameters such as lumen, vessel and plaque areas as well as in the composition of the atheroma between baseline and 2-years follow-up.When we separately examined the bifurcations located proximally and distally to the scaffolded segment, no changes were found at the distal bifurcations, while at the proximal bifurcations there was a statistical significant decrease in the plaque burden (36.67 ± 13.33% at baseline vs. 35.06 ± 13.20% at 2 years follow-up, p = 0.04).Ten necrotic core rich plaques were found at baseline, of which 2 regressed to either fibrotic plaque or to intimal thickening at 2 years follow-up. The other 8 did not change. Disease progression was noted in 3 plaques (1 adaptive intimal thickening, 1 fibrotic and 1 fibrocalcific plaque) that evolved to necrotic rich plaques. CONCLUSIONS: Plaque regression was noted at the bifurcations located proximally to the bioresorbable scaffold but not at these located distally. Additional studies are required to confirm this finding and examine further the effect of drug elution on atherosclerotic evolution.

The edge vascular response following implantation of the Absorb everolimus-eluting bioresorbable vascular scaffold and the XIENCE V metallic everolimus-eluting stent. First serial follow-up assessment at six months and two years: insights from the first-in-man ABSORB Cohort B and SPIRIT II trials.

AIMS: To assess serially the edge vascular response (EVR) of a bioresorbable vascular scaffold (BVS) compared to a metallic everolimus-eluting stent (EES). METHODS AND RESULTS: Non-serial evaluations of the Absorb BVS at one year have previously demonstrated proximal edge constrictive remodelling and distal edge changes in plaque composition with increase of the percent fibro-fatty (FF) tissue component. The 5 mm proximal and distal segments adjacent to the implanted devices were investigated serially with intravascular ultrasound (IVUS), post procedure, at six months and at two years, from the ABSORB Cohort B1 (n=45) and the SPIRIT II (n=113) trials. Twenty-two proximal and twenty-four distal edge segments were available for analysis in the ABSORB Cohort B1 trial. In the SPIRIT II trial, thirty-three proximal and forty-six distal edge segments were analysed. At the 5-mm proximal edge, the vessels treated with an Absorb BVS from post procedure to two years demonstrated a lumen loss (LL) of 6.68% (-17.33; 2.08) (p=0.027) with a trend toward plaque area increase of 7.55% (-4.68; 27.11) (p=0.06). At the 5-mm distal edge no major changes were evident at either time point. At the 5-mm proximal edge the vessels treated with a XIENCE V EES from post procedure to two years did not show any signs of LL, only plaque area decrease of 6.90% (-17.86; 4.23) (p=0.035). At the distal edge no major changes were evident with regard to either lumen area or vessel remodelling at the same time point. CONCLUSIONS: The IVUS-based serial evaluation of the EVR up to two years following implantation of a bioresorbable everolimus-eluting scaffold shows a statistically significant proximal edge LL; however, this finding did not seem to have any clinical implications in the serial assessment. The upcoming imaging follow-up of the Absorb BVS at three years is anticipated to provide further information regarding the vessel wall behaviour at the edges.

Advanced three-dimensional quantitative coronary angiographic assessment of bifurcation lesions: methodology and phantom validation.

AIMS: Validation of new three-dimensional (3-D) bifurcation quantitative coronary angiography (QCA) software. METHODS AND RESULTS: Cardiovascular Angiography Analysis System (CAAS 5v10) allows 3-D angiographic reconstructions based on two or more 2-D projection images. Measurements for minimal lumen diameter (MLD), reference vessel diameter (RVD), percent diameter stenosis (DS) and bifurcation angle (BA) were validated against precision manufactured phantom bifurcations. Length measurements were validated against angiographic measurement catheters inserted into a plexiglas bifurcation phantom. In 3-D reconstructions based on two 2-D images, acquired at variable rotation and angulation, accuracy and precision (mean difference ± SD) of the 11-segment model for MLD, RVD and DS were 0.013±0.131 mm, -0.052±0.039 mm and -1.08±5.13%, respectively; inter-observer variability was 0.141 mm, 0.058 mm and 5.42%, respectively. Adding the antero-posterior (optimal) projection to these basic reconstructions resulted in reduced variability (0.101 mm, 0.041 mm and 3.93% for MLD, RVD and DS, p<0.01 for all) and showed a trend towards improved precision (0.109 mm, 0.031 mm and 4.26%, respectively, p>0.05 for all). In basic reconstructions, accuracy and precision for BA was -1.3±5.0°, whereas inter-observer variability was 7.5°; respective measures for length were 0.15±0.26 mm and 0.54 mm. Adding the antero-posterior projection resulted in decreased precision (0.47 mm, p<0.01) and increased variability (1.03 mm, p<0.01) for length measurements; precision (5.4°) and variability (7.9°) for BA did not change significantly (p>0.30). CONCLUSIONS: Advances in the methodology of 3-D reconstruction and quantitative analysis for bifurcation lesions translated into highly accurate, precise and reproducible measures of diameter, length and BA.

Quantitative optical frequency domain imaging assessment of in-stent structures in patients with ST-segment elevation myocardial infarction: impact of imaging sampling rate.

BACKGROUND: The impact of the sampling rate (SR) of optical frequency domain imaging (OFDI) on quantitative assessment of in-stent structures (ISS) such as plaque prolapse and thrombus remains unexplored. METHODS AND RESULTS: OFDI after stenting was performed in ST-segment elevation myocardial infarction (STEMI) patients using a TERUMO OFDI system (Terumo Europe, Leuven, Belgium) with 160 frames/s and pullback speed of 20 mm/s. A total of 126 stented segments were analyzed. ISS were classified as either attached or non-attached to stent area boundaries. The volume, mean area and largest area of ISS were assessed according to 4 frequencies of SR, corresponding to distances between the analyzed frames of 0.125, 0.25, 0.50 and 1.0 mm. ISS volume was calculated by integrating cross-sectional ISS areas multiplied by each sampling distance using the disk summation method. The volume and mean area of ISS became significantly larger, while the largest area became significantly smaller as sampling distance became larger (1.11 mm(2) for 0.125 mm vs. 1.00 mm(2) for 1.0 mm, P for trend=0.036). In addition, variance of difference was positively associated with increasing width of sampling distance. CONCLUSIONS: Quantification of ISS is significantly influenced by the applied frequency of SR. This should be taken into account when designing future OFDI studies in which quantitative assessment of ISS is critical for the evaluation of STEMI patients.