Acute coronary syndromes most commonly arise from thrombosis of lipid-rich coronary atheromas that have large plaque burden despite angiographically appearing mild.
This study sought to examine the ...outcomes of percutaneous coronary intervention (PCI) of non–flow-limiting vulnerable plaques.
Three-vessel imaging was performed with a combination intravascular ultrasound (IVUS) and near-infrared spectroscopy (NIRS) catheter after successful PCI of all flow-limiting coronary lesions in 898 patients presenting with myocardial infarction (MI). Patients with an angiographically nonobstructive stenosis not intended for PCI but with IVUS plaque burden of ≥65% were randomized to treatment of the lesion with a bioresorbable vascular scaffold (BVS) plus guideline-directed medical therapy (GDMT) versus GDMT alone. The primary powered effectiveness endpoint was the IVUS-derived minimum lumen area (MLA) at protocol-driven 25-month follow-up. The primary (nonpowered) safety endpoint was randomized target lesion failure (cardiac death, target vessel–related MI, or clinically driven target lesion revascularization) at 24 months. The secondary (nonpowered) clinical effectiveness endpoint was randomized lesion–related major adverse cardiac events (cardiac death, MI, unstable angina, or progressive angina) at latest follow-up.
A total of 182 patients were randomized (93 BVS, 89 GDMT alone) at 15 centers. The median angiographic diameter stenosis of the randomized lesions was 41.6%; by near-infrared spectroscopy–IVUS, the median plaque burden was 73.7%, the median MLA was 2.9 mm2, and the median maximum lipid plaque content was 33.4%. Angiographic follow-up at 25 months was completed in 167 patients (91.8%), and the median clinical follow-up was 4.1 years. The follow-up MLA in BVS-treated lesions was 6.9 ± 2.6 mm2 compared with 3.0 ± 1.0 mm2 in GDMT alone–treated lesions (least square means difference: 3.9 mm2; 95% confidence interval: 3.3 to 4.5; p < 0.0001). Target lesion failure at 24 months occurred in similar rates of BVS-treated and GDMT alone–treated patients (4.3% vs. 4.5%; p = 0.96). Randomized lesion–related major adverse cardiac events occurred in 4.3% of BVS-treated patients versus 10.7% of GDMT alone–treated patients (odds ratio: 0.38; 95% confidence interval: 0.11 to 1.28; p = 0.12).
PCI of angiographically mild lesions with large plaque burden was safe, substantially enlarged the follow-up MLA, and was associated with favorable long-term clinical outcomes, warranting the performance of an adequately powered randomized trial. (PROSPECT ABSORB Providing Regional Observations to Study Predictors of Events in the Coronary Tree II Combined with a Randomized, Controlled, Intervention Trial; NCT02171065)
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Summary Background Percutaneous coronary intervention (PCI) is most commonly guided by angiography alone. Intravascular ultrasound (IVUS) guidance has been shown to reduce major adverse ...cardiovascular events (MACE) after PCI, principally by resulting in a larger postprocedure lumen than with angiographic guidance. Optical coherence tomography (OCT) provides higher resolution imaging than does IVUS, although findings from some studies suggest that it might lead to smaller luminal diameters after stent implantation. We sought to establish whether or not a novel OCT-based stent sizing strategy would result in a minimum stent area similar to or better than that achieved with IVUS guidance and better than that achieved with angiography guidance alone. Methods In this randomised controlled trial, we recruited patients aged 18 years or older undergoing PCI from 29 hospitals in eight countries. Eligible patients had one or more target lesions located in a native coronary artery with a visually estimated reference vessel diameter of 2·25–3·50 mm and a length of less than 40 mm. We excluded patients with left main or ostial right coronary artery stenoses, bypass graft stenoses, chronic total occlusions, planned two-stent bifurcations, and in-stent restenosis. Participants were randomly assigned (1:1:1; with use of an interactive web-based system in block sizes of three, stratified by site) to OCT guidance, IVUS guidance, or angiography-guided stent implantation. We did OCT-guided PCI using a specific protocol to establish stent length, diameter, and expansion according to reference segment external elastic lamina measurements. All patients underwent final OCT imaging (operators in the IVUS and angiography groups were masked to the OCT images). The primary efficacy endpoint was post-PCI minimum stent area, measured by OCT at a masked independent core laboratory at completion of enrolment, in all randomly allocated participants who had primary outcome data. The primary safety endpoint was procedural MACE. We tested non-inferiority of OCT guidance to IVUS guidance (with a non-inferiority margin of 1·0 mm2 ), superiority of OCT guidance to angiography guidance, and superiority of OCT guidance to IVUS guidance, in a hierarchical manner. This trial is registered with ClinicalTrials.gov , number NCT02471586. Findings Between May 13, 2015, and April 5, 2016, we randomly allocated 450 patients (158 35% to OCT, 146 32% to IVUS, and 146 32% to angiography), with 415 final OCT acquisitions analysed for the primary endpoint (140 34% in the OCT group, 135 33% in the IVUS group, and 140 34% in the angiography group). The final median minimum stent area was 5·79 mm2 (IQR 4·54–7·34) with OCT guidance, 5·89 mm2 (4·67–7·80) with IVUS guidance, and 5·49 mm2 (4·39–6·59) with angiography guidance. OCT guidance was non-inferior to IVUS guidance (one-sided 97·5% lower CI −0·70 mm2 ; p=0·001), but not superior (p=0·42). OCT guidance was also not superior to angiography guidance (p=0·12). We noted procedural MACE in four (3%) of 158 patients in the OCT group, one (1%) of 146 in the IVUS group, and one (1%) of 146 in the angiography group (OCT vs IVUS p=0·37; OCT vs angiography p=0·37). Interpretation OCT-guided PCI using a specific reference segment external elastic lamina-based stent optimisation strategy was safe and resulted in similar minimum stent area to that of IVUS-guided PCI. These data warrant a large-scale randomised trial to establish whether or not OCT guidance results in superior clinical outcomes to angiography guidance. Funding St Jude Medical.
Measuring fractional flow reserve (FFR) with a pressure wire remains underutilized because of the invasiveness of guide wire placement or the need for a hyperemic stimulus. FFR derived from routine ...coronary angiography (FFR
) eliminates both of these requirements and displays FFR values of the entire coronary tree. The FFR
Accuracy versus Standard FFR (FAST-FFR) study is a prospective, multicenter, international trial with the primary goal of determining the accuracy of FFR
.
Coronary angiography was performed in a routine fashion in patients with suspected coronary artery disease. FFR was measured in vessels with coronary lesions of varying severity using a coronary pressure wire and hyperemic stimulus. Based on angiograms of the respective arteries acquired in ≥2 different projections, on-site operators blinded to FFR then calculated FFR
using proprietary software. Coprimary end points were the sensitivity and specificity of the dichotomously scored FFR
for predicting pressure wire-derived FFR using a cutoff value of 0.80. The study was powered to meet prespecified performance goals for sensitivity and specificity.
Ten centers in the United States, Europe, and Israel enrolled a total of 301 subjects and 319 vessels meeting inclusion/exclusion criteria which were included in the final analysis. The mean FFR was 0.81 and 43% of vessels had an FFR≤0.80. The per-vessel sensitivity and specificity were 94% (95% CI, 88% to 97%) and 91% (86% to 95%), respectively, both of which exceeded the prespecified performance goals. The diagnostic accuracy of FFR
was 92% overall and remained high when only considering FFR values between 0.75 to 0.85 (87%). FFR
values correlated well with FFR measurements ( r=0.80, P<0.001) and the Bland-Altman 95% confidence limits were between -0.14 and 0.12. The device success rate for FFR
was 99%.
FFR
measured from the coronary angiogram alone has a high sensitivity, specificity, and accuracy compared with pressure wire-derived FFR. FFR
has the promise to substantially increase physiological coronary lesion assessment in the catheterization laboratory, thereby potentially leading to improved patient outcomes.
URL: https://www.clinicaltrials.gov . Unique Identifier: NCT03226262.
The aim of this study was to evaluate optical coherence tomography (OCT) and intravascular ultrasound (IVUS) versus coronary angiography in the assessment of target lesion calcification and its ...effect on stent expansion.
IVUS is more sensitive than angiography in the detection of coronary artery calcium, but the relationship among IVUS, OCT, and angiography has not been studied.
Overall, 440 lesions (440 patients with stable angina) underwent OCT- and IVUS-guided stent implantation. Coronary calcification was evaluated using: 1) angiography; 2) IVUS (maximum calcium angle and the surface pattern); and 3) OCT (mean and maximum calcium angle, calcium length, and maximum calcium thickness).
Median patient age was 66 years, and 82.5% were men. Among 440 lesions, calcium was detected by angiography in 40.2%, IVUS in 82.7%, and OCT in 76.8%. The maximum calcium angle, maximum calcium thickness, and calcium length by OCT or IVUS increased in relation to the increasing severity of angiographically visible calcium. In 13.2% of lesions with IVUS-detected calcium, calcium was either not visible or was underestimated (>90° smaller maximum arc) by OCT mostly due to superficial OCT plaque attenuation. In 21.6% of lesions with IVUS calcium angle >180°, angiography did not detect any calcium; these lesions had thinner and shorter calcium deposits as assessed using OCT, and final minimum stent area was larger compared to those with angiographically visible calcium. In lesions with thinner calcium deposits by OCT, IVUS detected a smooth surface with reverberations whereas thick calcium deposits were associated with an irregular surface without reverberations.
Angiographic detection of target lesion coronary calcium (compared to intravascular imaging) has not changed in the past 2 decades, and angiographically invisible calcium (only detectable by IVUS or OCT) did not appear to inhibit stent expansion.
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This study sought to determine the mechanistic effects of a novel balloon-based lithoplasty system on heavily calcified coronary lesions and subsequent stent placement using optical coherence ...tomography (OCT).
The Shockwave Coronary Rx Lithoplasty System (Shockwave Medical, Fremont, California) delivers localized, lithotripsy-enhanced disruption of calcium within the target lesion (i.e., lithoplasty) for vessel preparation before stent implantation.
We analyzed OCT findings in 31 patients in whom lithoplasty was used to treat severely calcified stenotic coronary lesions.
After lithoplasty, intraplaque calcium fracture was identified in 43% of lesions, with circumferential multiple fractures noted in >25%. The frequency of calcium fractures per lesion increased in the most severely calcified plaques (highest tertile vs. lowest tertile; p = 0.009), with a trend toward greater incidence of calcium fracture (77.8% vs. 22.2%; p = 0.057). Post-lithoplasty, mean acute area gain was 2.1 mm2, which further increased with stent implantation, achieving a minimal stent area of 5.94 ± 1.98 mm2 and mean stent expansion of 112.0 ± 37.2%. Deep dissections, as part of the angioplasty effect, occurred in 13% of cases and were successfully treated with stent implantation without incidence of acute closure, slow flow/no reflow, or perforation.
High-resolution imaging by OCT delineated calcium modification with fracture as a major mechanism of action of lithoplasty in vivo and demonstrated efficacy in the achievement of significant acute area gain and favorable stent expansion.
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This study sought to determine the anatomic characteristics and clinical presentation associated with a calcified nodule (CN) as assessed by optical coherence tomography.
CN is an unusual but ...demonstrable cause of acute coronary syndromes (ACS).
We studied 889 de novo culprit lesions in 889 patients (48% ACS) who underwent optical coherence tomography before intervention. CN was defined as an eruptive accumulation of nodular calcification (small fractured calcifications). Using quantitative coronary angiography, the change in the angle of the lesion between diastole and systole was measured (angiographic Δ angle).
CN was seen in 4.2% of all lesions and was located more frequently in the ostial or mid right coronary artery. Hemodialysis (odds ratio: 4.0; 95% confidence interval: 1.1 to 13.4; p = 0.04), in-lesion angiographic Δ angle (odds ratio: 1.09; 95% confidence interval: 1.05 to 1.14; p < 0.001), and maximum calcium arc by optical coherence tomography (odds ratio: 1.02; 95% confidence interval: 1.01 to 1.02; p < 0.001) were significantly associated with the presence of a CN in the multivariable model. When we compared CNs in patients with ACS versus stable angina presentation, there was a smaller minimum lumen area (1.04 mm2 first quartile, third quartile: 0.69, 1.26 vs. 1.61 first quartile, third quartile: 1.03, 2.06 mm2; p = 0.02) accompanied by more thrombus (82.4% vs. 20.0%; p < 0.001) in CN lesions with ACS presentation. In lesions with severe calcification (maximum calcium arc >180°), 30% of ACS culprit lesions contained a CN, and the presence of a CN was associated with ACS presentation independent of other vulnerable plaque morphologies.
The presence of a CN was associated with severe calcification and larger hinge movement of the coronary artery (especially ostial and mid right coronary artery). One-third of the underlying plaque morphology of severely calcified culprit lesions in patients with ACS was caused by a CN.
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This study aims to elucidate the relationships between the flexural strength and surface topography of composite resin blocks, utilized for the CAD/CAM system, after milling in various step-over ...amounts. The rectangular specimens were milled from CAD/CAM blocks with step-over amount 0.01, 0.02, 0.05, 0.1, and 0.2 mm; further, a three-point bending test was conducted to reveal the flexural strength. The surface morphology after milling was assessed by a 3D laser microscope. The surface roughness significantly decreased by reducing the step-over amount. Although there was significant association between the surface roughness and flexural strength by the Pearson correlation, the 95% confidence intervals of the flexural strength were between the mirror-polished and sand-blasted groups. These results suggest that a precise step-over amount enables us to obtain a smooth surface. Furthermore, the flexural strength of the rough surface milled by a large step-over amount caused no damage to the composite resin for CAD/CAM crown.
Objective
The primary objective was to demonstrate diagnostic equivalence between RFR and iFR in clinical practice.
Background
The instantaneous wave‐free ratio (iFR), a nonhyperemic pressure ratio ...(NHPR), has been shown to be noninferior to fractional flow reserve (FFR) in determining coronary artery stenosis severity in intermediate lesions. However, iFR has a number of inherent limitations, including sensitive landmarking of the pressure waveform and the assumption that maximal flow and minimal microcirculatory resistance occur during a fixed period within diastole. The resting full‐cycle ratio (RFR) is a novel NHPR which evaluates the entire cardiac cycle independent of the ECG, landmark identification, and timing within the cardiac cycle.
Methods
RE‐VALIDATE RFR was designed to determine the diagnostic utility of RFR for the physiological assessment of coronary artery disease in clinical practice compared to iFR. RFR was also tested for equivalence (1% margin), diagnostic accuracy, sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), areas under the receiver operated characteristic curve (AUC), and correlations compared to calculated iFR (iFRcalc).
Results
From two centers, 501 blinded rest‐ and hyperemic pressure recordings from 431 patients were suitable for analysis according to a core laboratory. The mean FFR, RFR, and iFRcalc were 0.80 ± 0.09, 0.90 ± 0.08, and 0.90 ± 0.08, respectively. Based on a binary cut‐off approach (RFR/iFR ≤0.89), RFR demonstrated equivalence with iFRcalc (95% confidence interval: 0.025–0.019) with overall diagnostic accuracy 97.8%, sensitivity 97.8%, specificity 97.8%, PPV 96.2%, NPV 98.7%, and AUC 0.96 (0.94–0.97, p < .001). RFR had a mean bias 0.003 (95% limits of agreement: 0.019, −0.025).
Conclusions
RFR was equivalent to iFR in clinical practice. RFR is an alternative NHPR, avoiding the need for hyperemic agents, thus potentially reducing side effects, procedural time and cost compared to FFR.
We sought to investigate the characteristics and prognostic impact of healed plaque (HP) detected by optical coherence tomography (OCT) in non-culprit segments in treated vessels.
OCT analysis ...included HP having a different optical intensity with clear demarcation from underlying plaque, thin-cap fibroatheroma (TCFA), and minimal lumen area. Non-culprit lesion (NCL) was defined as a plaque with >90° arc of disease (≥0.5 mm intimal thickness), length ≥2 mm, and location >5 mm from the stent edges. Major adverse cardiac event (MACE) included cardiac death, myocardial infarction (MI), or ischemia-driven revascularization (IDR).
We studied a total of 726 NCLs in 538 patients who underwent percutaneous coronary intervention with evaluable non-culprit segments by OCT. The prevalence of an HP was 17.8% (129/726) per lesion and 21.9% (118/538) per patient. At median follow-up of 2.2 years, there were 65 NCL-related MACE events, including 6 MIs and 65 IDRs of which 87.7% had a stable presentation. The presence of untreated HP was positively correlated with subsequent NCL-related MACE (hazard ratio HR 2.01, 95% confidence interval CI, 1.20–3.37, p < 0.01). There were 16 IDRs with stable angina occurring at a specific OCT-imaged NCL where an untreated HP was positively associated with subsequent NCL-related MACE (HR 3.72, 95% CI 1.35–10.30, p = 0.01) along with TCFA (HR 10.0, 95% CI 3.20–31.40, p < 0.01) and minimal lumen area <3.5 mm2 (HR 7.42, 95% CI 2.07–26.60, p < 0.01).
An OCT-detected HP in an NCL is a marker for future (mostly) stable non-culprit-related MACE at both a patient- and lesion-level.
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•Untreated healed plaque in PCI target vessel was present in 22% of patients.•Untreated healed plaque was related to future non-culprit-related events.•Untreated healed plaque could be a marker of atherosclerotic lesion progression.
Optical coherence tomography (OCT) imaging is considered to be the only imaging modality with sufficient resolution to measure fibrous cap thickness (FCT) in vivo. However, reproducibility of the ...measurements in vivo has been unsatisfactory.
The authors aimed to investigate whether satisfactory reproducibility of FCT measurements by OCT in vivo can be achieved between independent observers.
One hundred seventy OCT pullbacks were analyzed by 2 independent observers with intravascular imaging expertise in accordance with current guidelines to assess the interobserver variability of FCT measurement by intraclass correlation coefficient (ICC). The main sources of the variability were analyzed and incorporated in lesion assessment criteria. The same 170 OCT pullbacks were reanalyzed by the same observers using the developed criteria, and the interobserver reproducibility of the measurements was reassessed. On the basis of the developed criteria, a third independent observer interpreted all 170 OCT images. Assessment of the maximal lipid arc was also undertaken similarly before and after the development of interpretation criteria.
The original ICC of the FC thickness was 0.56 (95% confidence interval CI: 0.38 to 0.69). The poor definition of necrotic core facing border of FC and the neointimal presence of macrophages and calcification contributed to the high interobserver variability of FCT measurement. The ICC of FCT measurements by OCT in vivo was 0.88 (95% CI: 0.80 to 0.93) after we developed lesion assessment criteria. The ICC for the maximal lipid arc assessment before and after was 0.76 and 0.82 respectively. The third independent observer was extensively coached and returned the ICC of 0.82 (95% CI: 0.74 to 0.87) with observer 1 and 0.90 (95% CI: 0.86 to 0.94) with observer 2.
Careful consideration of OCT features mimicking fibroatheroma lesions and imaging artifacts contributed to significantly higher levels of interobserver agreement. Interobserver variation can be partially resolved by development of standard interpretation algorithms.
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