Photon-Counting Detector CT Virtual Monoenergetic Images for Coronary Artery Stenosis Quantification: Phantom and In Vivo Evaluation.

BACKGROUND. Calcium blooming causes stenosis overestimation on coronary CTA. OBJECTIVE. The purpose of this article was to evaluate the impact of virtual monoenergetic imaging (VMI) reconstruction level on coronary artery stenosis quantification using photon-counting detector (PCD) CT. METHODS. A phantom containing two custom-made vessels (representing 25% and 50% stenosis) underwent PCD CT acquisitions without and with simulated cardiac motion. A retrospective analysis was performed of 33 patients (seven women, 26 men; mean age, 71.3 ± 9.0 [SD] years; 64 coronary artery stenoses) who underwent coronary CTA by PCD CT followed by invasive coronary angiography (ICA). Scans were reconstructed at nine VMI energy levels (40-140 keV). Percentage diameter stenosis (PDS) was measured, and bias was determined from the ground-truth stenosis percentage in the phantom and ICA-derived quantitative coronary angiography measurements in patients. Extent of blooming artifact was measured in the phantom and in calcified and mixed plaques in patients. RESULTS. In the phantom, PDS decreased for 25% stenosis from 59.9% (40 keV) to 13.4% (140 keV) and for 50% stenosis from 81.6% (40 keV) to 42.3% (140 keV). PDS showed lowest bias for 25% stenosis at 90 keV (bias, 1.4%) and for 50% stenosis at 100 keV (bias, -0.4%). Blooming artifacts decreased for 25% stenosis from 61.5% (40 keV) to 35.4% (140 keV) and for 50% stenosis from 82.7% (40 keV) to 52.1% (140 keV). In patients, PDS for calcified plaque decreased from 70.8% (40 keV) to 57.3% (140 keV), for mixed plaque decreased from 69.8% (40 keV) to 56.3% (140 keV), and for noncalcified plaque was 46.6% at 40 keV and 54.6% at 140 keV. PDS showed lowest bias for calcified plaque at 100 keV (bias, 17.2%), for mixed plaque at 140 keV (bias, 5.0%), and for noncalcified plaque at 40 keV (bias, -0.5%). Blooming artifacts decreased for calcified plaque from 78.4% (40 keV) to 48.6% (140 keV) and for mixed plaque from 73.1% (40 keV) to 44.7% (140 keV). CONCLUSION. For calcified and mixed plaque, stenosis severity measurements and blooming artifacts decreased at increasing VMI reconstruction levels. CLINICAL IMPACT. PCD CT with VMI reconstruction helps overcome current limitations in stenosis quantification on coronary CTA.

Relative increase in production ratio of small dense low-density lipoprotein in acute coronary syndrome with high coronary plaque burden: an ex-vivo analysis.

The absolute value of small dense low-density lipoprotein (sd-LDL) including small LDL (s-LDL) and very small LDL (vs-LDL) has been shown to be associated with increased incidence of atherosclerosis. However, the impact of short-timeframe increases in sd-LDL on arteriosclerosis has not yet been elucidated. Therefore, we investigated the clinical roles of ex-vivo induced sd-LDL in acute coronary syndrome (ACS) using a novel method. This is a prospective, single-blind, and observational study that screened patients who underwent coronary angiography (CAG) for the treatment of ACS or investigation of heart-failure etiology between June 2020 and April 2022 (n = 247). After excluding patients with known diabetes mellitus and advanced renal disease, the patients were further divided into the ACS (n = 34) and control (non-obstructive coronary artery, n = 34) groups. The proportion of sd-LDL (s-LDL + vs-LDL) in total lipoproteins was observed before and after 2-h incubation at 37 ℃ (to approximate physiologic conditions) using 3% polyacrylamide gel electrophoresis. The coronary plaque burden was quantified upon CAG in the ACS group. There were no significant differences between the ACS and control groups in terms of clinical coronary risk factors. The baseline of large, medium, small, and very small LDL were comparable between the two groups. Following a 2-h incubation period, significant increases were observed in the ratios of s-LDL and vs-LDL in both the ACS and control groups (ACS, p = 0.01*; control, p = 0.01*). Notably, the magnitude of increase in sd-LDL was more pronounced in the ACS group compared to the control group, with s-LDL showing a significant difference (p = 0.03*) and vs-LDL showing a tread toward significance (p = 0.08). In addition, in both groups, there was a decrease in IDL and L-LDL, while M-LDL remained unchanged. The plaque burden index and rate of short-timeframe changes in both s-LDL (p = 0.01*) and vs-LDL (p = 0.04*) before and after incubation were significantly correlated in the ACS group. The enhanced production rate of sd-LDL induced under short-term physiologic culture in an ex-vivo model was greater in patients with ACS than in the control group. The increase in sd-LDL is positively correlated with coronary plaque burden. Short-timeframe changes in sd-LDL may serve as markers for the severity of coronary artery disease.

Comparison between the diagnostic performance of vessel fractional flow reserve and nonhyperemic pressure ratio for functionally significant coronary stenosis severity as assessed by fractional flow reserve.

BACKGROUND: Fractional flow reserve (FFR) and nonhyperemic pressure ratios (NHPRs) have been widely used to assess the functional severity of coronary stenosis. However, their measurement requires using a pressure wire, making their use in all patients difficult. The recently developed vessel fractional flow reserve (vFFR), derived from three-dimensional quantitative coronary angiography, is expected to serve as a surrogate for pressure wire assessment. METHODS: This retrospective study was conducted on patients with intermediate coronary stenosis who underwent FFR and NHPR measurements. The vFFR and NHPR values were compared for diagnosing coronary stenosis as defined by an FFR of ≤0.80, and the number of patients not requiring wire-based assessment was estimated. RESULTS: In a total of 90 lesions from 74 patients (median [SD] age 75 [12] years; men 80%), the median FFR was 0.78 (0.72-0.84), and 57% of these lesions (N = 51) exhibited an FFR of ≤0.80. vFFR provided high discrimination for coronary stenosis (area under the curve 0.80, 95% confidence interval 0.70-0.90), which was comparable to that of NHPRs (p = 0.42). High diagnostic accuracy was consistently observed across a variety of clinical presentations (i.e., old age, diabetes, target coronary artery, and left ventricular hypertrophy) (pinteraction > 0.05). In total, 55 lesions (61%) demonstrated positive or negative likelihood of coronary stenosis when vFFR was <0.73 (specificity 90%) or >0.87 (sensitivity 88%), respectively. CONCLUSION: vFFR demonstrated excellent diagnostic performance for detecting functionally significant coronary stenosis as evaluated by FFR. vFFR may be used as a surrogate for pressure wire assessment.

Comparison of quantitative flow ratio with instantaneous wave-free ratio and resting full-cycle ratio during daily routine in the catheterization laboratory.

BACKGROUND: Quantitative flow ratio (QFR) is a novel, software-based method to evaluate the physiology of coronary lesions. The aim of this study was to compare QFR with the established invasive measurements of coronary blood flow using instantaneous wave-free ratio (iFR) or resting full-cycle ratio (RFR) in daily cathlab routine. METHODS: 102 patients with stable coronary artery disease and a coronary stenosis of 40%-90% were simultaneously assessed with QFR and iFR or RFR. QFR-computation was performed by two certified experts using the appropriate software (QAngio XA 3D 3.2). RESULTS: QFR showed a significant correlation (r = 0.75, p < 0.001) to iFR and RFR. The area under the receiver curve for all measurements was 0.93 (95% confidence interval, 0.87-0.98) for QFR compared to iFR or RFR. QFR based assessment required less time with a median of 501 s (IQR 421-659 s) compared to iFR or RFR which required a median of 734 s to obtain the result (IQR 512-967 s; p < 0.001). The median use of contrast medium was similar with 21 mL (IQR 16-30 mL) for the QFR-based and 22 mL (IQR 15-35 mL) for the iFR- or RFR-based diagnostic. QFR diagnostic required less radiation. The median dose area product for QFR was 307cGycm2 (IQR 151-429 cGycm2 ) compared to 599 cGycm2 (IQR 345-1082 cGycm2 ) for iFR or RFR, p < 0.001. CONCLUSION: QFR measurements of coronary artery blood flow correlate with iFR or RFR measurements and are associated with shorter procedure times and reduced radiation dose.

Impact of physiologically diffuse versus focal pattern of coronary disease on quantitative flow reserve diagnostic accuracy.

BACKGROUND: Fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR) disagree in about 20% of intermediate coronary lesions. As the physiological pattern of coronary artery disease has a significant influence on FFR-iFR discordance, we sought to assess it may impact on the diagnostic accuracy of quantitative flow reserve (QFR). METHODS: One hundred and ninety-four patients with 224 intermediate coronary lesions were investigated with iFR, FFR, and QFR. The physiological pattern of disease was assessed with iFR Scout pullback and QFR virtual pullback in all the cases. RESULTS: A predominantly physiologically focal pattern was observed in 81 (36.2%) lesions, whereas a predominantly physiologically diffuse was observed in 143 (63.8%) cases. QFR demonstrated a significant correlation (r = 0.581, p < 0.001) and a substantial agreement with iFR, both in diffuse (AUC = 0.798) and in focal (AUC = 0.812) pattern of disease. Discordance between QFR and iFR was observed in 51 (22.8%) lesions, consisting of iFR+/QFR- (64.7%) and iFR-/QFR+ (35.3%). Notably, the physiological pattern of disease was the only variable significantly associated with iFR/QFR discordance. QFR virtual pullback demonstrated an excellent agreement (83.9%) with iFR Scout pullback in classifying the physiological pattern of disease. CONCLUSIONS: QFR has a good diagnostic accuracy in assessing myocardial ischemia independently of the pattern of coronary disease. However, the physiological pattern of disease has an influence on the QFR/iFR discordance, which occurs in ~20% of the cases. The QFR virtual pullback correctly defined the physiological pattern of disease in the majority of the cases using the iFR pullback as reference.

Elastic stent recoil in coronary total occlusions: Comparison of durable-polymer zotarolimus eluting stent and ultrathin strut bioabsorbable-polymer sirolimus eluting stent.

OBJECTIVES: To compare stent recoil (SR) of the thin-strut durable-polymer Zotarolimus-eluting stent (dp-ZES) and the ultrathin-strut bioabsorbable-polymer Sirolimus-eluting stent (bp-SES) in chronic total occlusions (CTOs) and to investigate the predictors of high SR in CTOs. BACKGROUND: Newer ultrathin drug eluting stent might be associated with lower radial force and higher elastic recoil due to the thinner strut design, possibly impacting on the rate of in-stent restenosis and thrombosis. METHODS: Between January 2017 and November 2019, consecutive patients with CTOs undergoing percutaneous coronary intervention were evaluated. Only patients treated with dp-ZES or bp-SES were included and stratified accordingly. Quantitative coronary angiography analysis was used to assess absolute SR, relative SR, absolute focal SR, relative focal SR, high absolute, and high relative focal SR. RESULTS: A total of 128 lesions (67 treated with dp-ZES and 61 with bp-SES) in 123 patients were analyzed. Between bp-SES and dp-ZES no differences were found in absolute SR (p = .188), relative SR (p = .138), absolute focal SR (p = .069), and relative focal SR (p = .064). High absolute and high relative focal SR occurred more frequently in bp-SES than in dp-ZES (p = .004 and p = .015). Bp-SES was a predictor of high absolute focal SR (Odds ratio [OR] 3.29, 95% confidence interval [CI] 1.50-7.22, p = .003]. High-pressure postdilation and bp-SES were predictors of high relative focal SR (OR 2.22, 95% CI 1.01-4.86, p = .047; OR 2.74, 95% CI 1.24-6.02, p = .012, respectively). CONCLUSIONS: Both stents showed an overall low SR. However, ultra-thin strut bp-SES was a predictor of high absolute and high relative focal SR.

Diagnostic accuracy of angiography-based vessel fractional flow reserve after chronic coronary total occlusion recanalization.

BACKGROUND: Angiography-based vessel fractional flow reserve (vFFR) demonstrated a strong correlation with invasive fractional flow reserve (FFR) in both a pre- and post-percutaneous coronary intervention (PCI) setting. However, the role of vFFR and its correlation with post-PCI FFR in chronic coronary occlusions (CTO) has not been evaluated yet. We sought to investigate the diagnostic performance of post-PCI vFFR with post-PCI FFR as a reference in patients undergoing successful CTO PCI. METHODS: Between March 2016 and April 2020, a total of 80 patients from the FFR-SEARCH (prospective registry) and FFR REACT (randomized controlled trial) studies underwent successful CTO recanalization with post-PCI FFR measurements. RESULTS: A total of 50 patients (median age 66 (interquartile range [IQR]: 56-74) years, 76% were male) were eligible for the analysis. Median post-PCI FFR was 0.89 (IQR: 0.84-0.94), while median post-PCI vFFR was 0.91 (IQR: 0.85-0.94) (p 0.10). Suboptimal physiological results, defined as FFR and vFFR <0.90, were identified in 26 (52%) and in 21 (42%) patients, respectively. A strong correlation (r = 0.82) was found between vFFR and FFR with a mean bias of 0.013 ± 0.051. Receiver-operating characteristics curve analysis revealed an excellent accuracy of vFFR in predicting FFR <0.90 (area under the curve: 0.97; 95% confidence interval: 0.93-1.00). CONCLUSION: Post-PCI vFFR shows a good correlation with post-PCI FFR and a high diagnostic accuracy for post-PCI FFR ≤0.90 in patients undergoing successful PCI of a CTO lesion.

Coronary CTA With AI-QCT Interpretation: Comparison With Myocardial Perfusion Imaging for Detection of Obstructive Stenosis Using Invasive Angiography as Reference Standard.

BACKGROUND. Deep learning frameworks have been applied to interpretation of coronary CTA performed for coronary artery disease (CAD) evaluation. OBJECTIVE. The purpose of our study was to compare the diagnostic performance of myocardial perfusion imaging (MPI) and coronary CTA with artificial intelligence quantitative CT (AI-QCT) interpretation for detection of obstructive CAD on invasive angiography and to assess the downstream impact of including coronary CTA with AI-QCT in diagnostic algorithms. METHODS. This study entailed a retrospective post hoc analysis of the derivation cohort of the prospective 23-center Computed Tomographic Evaluation of Atherosclerotic Determinants of Myocardial Ischemia (CREDENCE) trial. The study included 301 patients (88 women and 213 men; mean age, 64.4 ± 10.2 [SD] years) recruited from May 2014 to May 2017 with stable symptoms of myocardial ischemia referred for nonemergent invasive angiography. Patients underwent coronary CTA and MPI before angiography with quantitative coronary angiography (QCA) measurements and fractional flow reserve (FFR). CTA examinations were analyzed using an FDA-cleared cloud-based software platform that performs AI-QCT for stenosis determination. Diagnostic performance was evaluated. Diagnostic algorithms were compared. RESULTS. Among 102 patients with no ischemia on MPI, AI-QCT identified obstructive (≥ 50%) stenosis in 54% of patients, including severe (≥ 70%) stenosis in 20%. Among 199 patients with ischemia on MPI, AI-QCT identified nonobstructive (1-49%) stenosis in 23%. AI-QCT had significantly higher AUC (all p < .001) than MPI for predicting ≥ 50% stenosis by QCA (0.88 vs 0.66), ≥ 70% stenosis by QCA (0.92 vs 0.81), and FFR < 0.80 (0.90 vs 0.71). An AI-QCT result of ≥ 50% stenosis and ischemia on stress MPI had sensitivity of 95% versus 74% and specificity of 63% versus 43% for detecting ≥ 50% stenosis by QCA measurement. Compared with performing MPI in all patients and those showing ischemia undergoing invasive angiography, a scenario of performing coronary CTA with AIQCT in all patients and those showing ≥ 70% stenosis undergoing invasive angiography would reduce invasive angiography utilization by 39%; a scenario of performing MPI in all patients and those showing ischemia undergoing coronary CTA with AI-QCT and those with ≥ 70% stenosis on AI-QCT undergoing invasive angiography would reduce invasive angiography utilization by 49%. CONCLUSION. Coronary CTA with AI-QCT had higher diagnostic performance than MPI for detecting obstructive CAD. CLINICAL IMPACT. A diagnostic algorithm incorporating AI-QCT could substantially reduce unnecessary downstream invasive testing and costs. TRIAL REGISTRATION. Clinicaltrials.gov NCT02173275.

Reclassification of Treatment Strategy with Fractional Flow Reserve in Cancer Patients with Coronary Artery Disease.

Background and Objectives: Cancer and coronary artery disease (CAD) often coexist. Compared to quantitative coronary angiography (QCA), fractional flow reserve (FFR) has emerged as a more reliable method of identifying significant coronary stenoses. We aimed to assess the specific management, safety and outcomes of FFR-guided percutaneous coronary intervention (PCI) in cancer patients with stable CAD. Materials and Methods: FFR was used to assess cancer patients that underwent coronary angiography for stable CAD between September 2008 and May 2016, and were found to have ≥50% stenosis by QCA. Patients with lesions with an FFR > 0.75 received medical therapy alone, while those with FFR ≤ 0.75 were revascularized. Procedure-related complications, all-cause mortality, nonfatal myocardial infarction, or urgent revascularizations were analyzed. Results: Fifty-seven patients with stable CAD underwent FFR on 57 lesions. Out of 31 patients with ≥70% stenosis as measured by QCA, 14 (45.1%) had an FFR ≥ 0.75 and lesions were reclassified as moderate and did not receive PCI nor DAPT. Out of 26 patients with <70% stenosis as measured by QCA, 6 (23%) had an FFR < 0.75 and were reclassified as severe and were treated with PCI and associated DAPT. No periprocedural complications, urgent revascularization, acute coronary syndromes, or cardiovascular deaths were noted. There was a 22.8% mortality at 1 year, all cancer related. Patients who received a stent by FFR assessment showed a significant association with decreased risk of all-cause death (HR: 0.37, 95% CI 0.15−0.90, p = 0.03). Conclusions: Further studies are needed to define the optimal therapeutic approach for cancer patients with CAD. Using an FFR cut-off point of 0.75 to guide PCI translates into fewer interventions and can facilitate cancer care. There was an overall reduction in mortality in patients that received a stent, suggesting increased resilience to cancer therapy and progression.

Validation of novel 3-dimensional quantitative coronary angiography based software to calculate fractional flow reserve post stenting.

OBJECTIVES: To validate novel dedicated 3D-QCA based on the software to calculate post PCI vessel-FFR (vFFR) in a consecutive series of patients, to assess the diagnostic accuracy, and to assess inter-observer variability. BACKGROUND: Low post percutaneous coronary intervention (PCI) fractional flow reserve (FFR) predicts future adverse cardiac events. However, FFR assessment requires the insertion of a pressure wire in combination with the use of a hyperemic agent. METHODS: FAST POST study is an observational, retrospective, single-center cohort study. One hundred patients presenting with stable angina or non ST-elevation myocardial infarction, who underwent post PCI FFR assessment using a dedicated microcatheter were included. Two orthogonal angiographic projections were acquired to create a 3D reconstruction of the coronary artery using the CAAS workstation 8.0. vFFR was subsequently calculated using the aortic root pressure. RESULTS: Mean age was 65±12 years and 70% were male. Mean microcatheter based FFR and vFFR were 0.91±0.07 and 0.91±0.06, respectively. A good linear correlation was found between FFR and vFFR (r = 0.88; p <.001). vFFR had a higher accuracy in the identification of patients with FFR values <0.90, AUC 0.98 (95% CI: 0.96-1.00) as compared with 3D-QCA AUC 0.62 (95% CI: 0.94-0.74). Assessment of vFFR had a low inter-observer variability (r = 0.95; p <.001). CONCLUSION: 3D-QCA derived post PCI vFFR correlates well with invasively measured microcatheter based FFR and has a high diagnostic accuracy to detect FFR <0.90 with low inter-observer variability.

Prognostic value of quantitative flow ratio measured immediately after drug-coated balloon angioplasty for in-stent restenosis.

OBJECTIVES: This study aimed to evaluate prognostic value of quantitative flow ratio (QFR) in drug-coated balloon (DCB) angioplasty for in-stent restenosis (ISR). BACKGROUND: There is a high incidence of recurrent ISR after DCB angioplasty. QFR is a novel method for fast computation of fractional flow reserve for the target vessel based on quantitative coronary angiography (QCA) and fluid dynamics algorithms. METHODS: Patients participating in the RESTORE ISR China randomized trial were enrolled and classified into the recurrent restenosis group and the non-recurrent restenosis group. The binary classifications followed the QCA standards of ISR. Clinical and angiographic characteristics of the groups were analyzed, and the QFRs before and after lesion preparation and after final DCB angioplasty were measured and compared. RESULTS: A total of 208 patients who underwent follow-up angiography were enrolled in the study, with 226 lesions measured in total. QFR value after DCB angioplasty (odds ratio [OR] 0.88; 95% confidence interval [CI] 0.83-0.93; p < .0001 for 1 mm increase), lesion length (OR: 1.08; 95% CI: 1.01-1.15; p = .017), and vessel caliber lumen diameter (OR: 0.35; 95% CI 0.13-0.89; p = .027) were independently associated with recurrent restenosis after DCB angioplasty. The optimal QFR cut-off value was determined to be 0.90 with a sensitivity of 0.94, specificity of 0.56, and accuracy of 0.79 in predicting recurrent restenosis. CONCLUSIONS: The QFR value after DCB angioplasty is a promising predictor of DES ISR.

Quantitative flow ratio-Meta-analysis and systematic review.

INTRODUCTION: Despite of the wide evidence of use fractional flow reserve (FFR), isolated angiography evaluation is still the main tool to indicate percutaneous coronary intervention. Quantitative flow ratio (QFR) is a new functional index to assess functional significance. Recently, few studies have showed the capacity of QFR to predict significance stenosis. The aim of this research has been to describe the evidence of QFR in this clinical setting, to analyze the global diagnosis accuracy of QFR versus FFR and to compare the difference in feasibility between retrospective and prospective analysis. METHODS AND RESULTS: Systematic review of literature was performed. Eligible studies for the meta-analysis were considered those directly evaluating de QFR versus FFR. Pooled values of diagnosis test and summary receiver operator curve were calculated. Main causes of not-perform QFR analysis according to study design were also evaluated. Sixteen studies were included. Good correlation and agreement were showed. Global sensibility, specificity, PPV, and NPV were 0.84, 0.89, 0.80, and 0.92, respectively. Then, 18% of evaluated vessels could not be analyzed. Significant differences were found in the percentage of discarded vessels and the cause of nonperformed analysis between retrospective or prospective analysis. CONCLUSIONS: Excellent correlation and agreement between QFR and FFR was demonstrated. QFR assessment could be improved by its prospective analysis with a dedicated protocol.

Future culprit detection based on angiography-derived FFR.

OBJECTIVES: We sought to characterize the hemodynamic impact of mild coronary artery disease (CAD) using quantitative flow ratio (QFR, an angiography-derived fractional flow reserve [FFR]) in a population of patients with only non-significant CAD at baseline that subsequently experienced a myocardial infarction (MI). BACKGROUND: The discriminatory value of FFR in patients with mild CAD remains imperfect. METHODS: We retrospectively included patients who underwent invasive coronary angiography for an MI, in whom another angiogram had been performed within the previous 5 years. Three-dimensional quantitative coronary angiography, QFR, and lesion length analysis were conducted on lesions responsible for the MI (future culprit lesions, [FCL]) as well as on control lesions (non-culprit lesions, [NCL]). RESULTS: Eighty-three FCL and 117 NCL were analyzed in 83 patients: FCL were more severe (median % diameter of stenosis [DS] 39.1% [29.8; 45.7] vs. 29.8% [25.0; 37.2], p < .001), had lower QFR values (0.94 [0.86; 0.98] vs. 0.98 [0.96; 1.00], p < .001) and tended to be longer (15.2 mm [10.0; 27.3] vs. 12.7 mm [9.3; 22.4], p = .070) than NCL. In lesions with an interval < 2 years between baseline angiography and MI, the difference in QFR was more pronounced compared to the lesions with a longer interval (FCL: 0.92 [0.85; 0.97] vs. NCL: 0.98 [0.94; 1.00], p < .001 and FCL: 0.96 [0.88; 1.00] vs. NCL: 0.98 [0.96;1.00], p = .006 respectively) CONCLUSION: Mild coronary stenoses that are subsequently responsible for an MI (FCL) exhibit a higher DS and lower QFR years before the event. Furthermore, FCL with a lower QFR at baseline appear to lead earlier to MI.

Imaging and 2-year clinical outcomes of thin strut sirolimus-eluting bioresorbable vascular scaffold: The MeRes-1 extend trial.

OBJECTIVES: This study explores the safety and efficacy of thin strut MeRes100 sirolimus-eluting bioresorbable vascular scaffold (BRS) in patients with de novo coronary artery lesions. BACKGROUND: In interventional cardiology, the emergence of BRS technology is catalyzing the next paradigm shift. METHODS: The MeRes-1 Extend was a multicenter, prospective, single-arm, open-label study enrolling 64 patients in Spain, Macedonia, Brazil, South Africa, Malaysia, and Indonesia. The safety endpoint was major adverse cardiac events (MACE) which composed of cardiac death, myocardial infarction (MI), and ischemia-driven target lesion revascularization (ID-TLR). The imaging efficacy endpoint was mean in-scaffold late lumen loss (LLL) evaluated by quantitative coronary angiography (QCA). Optical coherence tomography (OCT) imaging was performed at baseline and 6-month follow-up. RESULTS: A total of 69 target lesions were identified in 64 enrolled patients (mean age 58.30 ± 9.02 years). Of the treated lesions, 49 (71.01%) lesions were of type B2/C. Procedural and device success was achieved in 64 and 62 patients, respectively. At 2-year follow-up, MACE was reported in one patient (1.61%) in the form of ID-TLR. There was no case of MI, cardiac death or scaffold thrombosis through 2-year. In a subset of 32 patients, paired QCA showed mean in-scaffold LLL of 0.18 ± 0.31 mm at 6-month follow-up. In a subset of 21 patients, OCT revealed 97.95 ± 3.69% strut coverage with mean scaffold area of 7.56 ± 1.79 mm2 and no evidence of strut malapposition. CONCLUSIONS: The clinical and imaging outcomes of MeRes-1 Extend trial demonstrated favorable safety and efficacy of MeRes100 sirolimus-eluting BRS in patients with de novo coronary artery lesions.

Determinants of visual-functional mismatches as assessed by coronary angiography and quantitative flow ratio.

OBJECTIVE: We aimed to evaluate the determinants of visual-functional mismatches between quantitative coronary angiography (QCA) and the quantitative flow ratio (QFR). BACKGROUND: The fractional flow reserve (FFR) has been established as a method to estimate the functional stenosis severity of coronary artery disease and to optimize decision-making for revascularization. The QFR is a novel angiography-derived computational index that can estimate the FFR without pharmacologically induced hyperemia or the use of pressure wire. METHODS: A total of 504 de novo intermediate-to-severe stable lesions that underwent angiographic and physiological assessments were analyzed. All lesions were divided into four groups based on the significance of visual (QCA-diameter stenosis [DS] > 50% and ≤ 50%) and functional (QFR ≤ 0.80 and > 0.80) stenosis severity. Patient characteristics, angiographic findings, and physiological indices were compared. RESULTS: One-hundred seventy-eight lesions (35.3%) showed discordant visual-functional assessments; mismatch (QCA-DS > 50% and QFR > 0.80) in 75 lesions (14.9%) and reverse mismatch (QCA-DS ≤ 50% and QFR ≤ 0.80) in 103 lesions (20.4%), respectively. Reverse mismatch was associated with non-diabetes, lower ejection fraction, higher Duke jeopardy score, and lower coronary flow reserve (CFR). Mismatch was associated with smaller QCA-DS, larger reference diameter, shorter lesion length, lower Duke jeopardy score, and higher CFR. Lesion location and microcirculatory resistance was not associated with the prevalence of mismatches. Reverse mismatch group had the higher prevalence of discordant decision-makings between QFR and FFR than the other three groups. CONCLUSIONS: The CFR and subtended myocardial mass were predictors of visual-functional mismatches between QCA-DS and the QFR. Caution should be exercised in lesions showing QCA-DS/QFR reverse mismatch.

Bioresorbable scaffold implantation in STEMI patients: 5 years imaging subanalysis of PRAGUE-19 study.

BACKGROUND: Bioresorbable scaffold (BRS) Absorb™ clinical use has been stopped due to higher rate of device thrombosis. Scaffold struts persist longer than 2 years in the vessel wall. Second generation devices are being developed. This study evaluates long-term invasive imaging in STEMI patients. METHODS: PRAGUE-19 study is an academic study enrolling consecutive STEMI patients with intention to implant Absorb™ BRS. A total of 83 STEMI patients between December 2012 and March 2014 fulfilled entry criteria. Coronary angiography and optical coherence tomography at 5 year follow-up was performed in 25 patients. RESULTS: Primary combined clinical endpoint (death, myocardial infarction or target vessel revascularization) occurred in 12.6% during the five-year follow-up with overall mortality 6.3%. Definite scaffold thrombosis occurred in 2 patients in the early phase after BRS implantation. Quantitative coronary angiography after 5 years demonstrated low late lumen loss of 0.11 ± 0.35 mm with binary restenosis rate of 0%. Optical coherence tomography demonstrated complete resorption of scaffold struts and mean lumen diameter of 3.25 ± 0.30 and 3.22 ± 0.49 (P = 0.73) at baseline and after 5 years, respectively. Three patients developed small coronary artery aneurysm in the treated segment. CONCLUSION: Invasive imaging results 5 years after BRS implantation in STEMI showed complete resorption of scaffold struts and stable lumen vessel diameter. Trial registration ISRCTN43696201 (retrospectivelly registred, June 7th, 2019). https://www.isrctn.com/ISRCTN43696201.

Increased Serum Malondialdehyde-Modified Low-Density Lipoprotein and Coronary Angiographic Progression After Drug-Eluting Stent Implantation in Patients With Stable Angina.

BACKGROUND: Cardiac events can occur after drug-eluting stent (DES) implantation due to coronary plaque progression at non-stented sites. Malondialdehyde-modified low-density lipoprotein (MDA-LDL) is suggested to be an atherogenic marker. This study investigated the relationship between serum MDA-LDL and angiographic progression after DES implantation.Methods and Results:In total, 207 patients who underwent percutaneous coronary intervention (PCI) using DES and follow-up coronary angiography were retrospectively analyzed. MDA-LDL was serially measured before PCI and at follow up. Persistent high MDA-LDL was defined as a MDA-LDL level more than the median value both before PCI and at follow up. Angiographic progression was assessed by serial analysis of quantitative coronary angiography. Angiographic progression occurred in 35 patients (16.9%). MDA-LDL before PCI was significantly higher in the progression group than the non-progression group in all patients (143.4±35.8 U/L vs. 103.0±33.5U/L, P<0.001) and in patients with controlled LDL-cholesterol (LDL-C <100 mg/dL both before PCI and at follow up; 121.8±32.7 U/L vs. 84.9±24.9 U/L, P<0.001). There were positive correlations between % diameter stenosis changes and serum MDA-LDL before PCI in all patients (r=0.33, P<0.01) and those with controlled LDL-C (r=0.23, P=0.04). In multivariate logistic regression analysis, persistent high MDA-LDL was an independent predictor of plaque progression. CONCLUSIONS: Increased serum MDA-LDL was associated with angiographic progression after DES implantation.

Comparison of Archival Angiographic Findings in Patients Later Developing Acute Coronary Syndrome or Stable Angina.

Acute coronary syndrome (ACS) can develop in patients with mildly to moderately stenotic lesions. However, the angiographic characteristics of lesions in patients who will later develop ACS have not been systematically investigated. For this reason, we examined the earlier angiographic findings of such patients in a retrospective study.The study population consisted of 45 consecutive ACS and 45 stable angina (SA) patients who require revascularization. All of them had received cardiac catheterization within 5 years prior to onset, for different reasons. The detailed parameters of the earlier coronary angiographies at the culprit site the whole culprit vessel, and all three vessels were compared between the two groups.Mild-to-moderate stenosis was present exclusively at the culprit site in the earlier angiographies, both in ACS and SA patients. Lesions associated with ACS progression were significantly shorter in length than those associated with SA progression (11.5 ± 5.5 versus 16.1 ± 10.5 mm, P = 0.02) and were more eccentric (eccentricity index: 0.5 ± 0.3 versus 0.7 ± 0.3, P = 0.04). Percent diameter stenosis was similar (42.2 ± 14.5 versus 44.0 ± 13.8%, P = 0.5). The mean grading scores for plaque extension and size (1-3) were significantly lower in ACS than in SA (1.4 ± 0.6 versus 1.8 ± 0.6, P = 0.01, and 1.3 ± 0.6 versus 1.7 ± 0.7, P = 0.01, respectively). Residual SYNTAX scores were significantly lower in ACS (12.5 ± 7.4 versus 16.4 ± 8.6, P = 0.03).Despite equivalent degrees of stenosis in previous angiographies, ACS occurred more frequently in patients with more focal and eccentric lesions but with less diseased coronary arteries than SA.

Diagnostic performance of quantitative flow ratio in prospectively enrolled patients: An individual patient-data meta-analysis.

OBJECTIVES: We aimed to provide robust performance estimates for quantitative flow ratio (QFR) in assessment of intermediary coronary lesions. BACKGROUND: Angiography-based functional lesion assessment by QFR may appear as a cost saving and safe approach to expand the use of physiology-guided percutaneous coronary interventions. QFR was proven feasible and showed good diagnostic performance in mid-sized off-line and on-line studies with fractional flow reserve (FFR) as reference standard. METHODS: We performed a collaborative individual patient-data meta-analysis of all available prospective studies with paired assessment of QFR and FFR using the CE-marked QFR application. The main outcome was agreement of QFR and FFR using a two-step analysis strategy with a multilevel mixed model accounting for study and center level variation. RESULTS: Of 16 studies identified, four studies had prospective enrollment and provided patient level data reaching a total of 819 patients and 969 vessels with paired FFR and QFR: FAVOR Pilot (n = 73); WIFI II (n = 170); FAVOR II China (n = 304) and FAVOR II Europe-Japan (n = 272). We found an overall agreement (mean difference 0.009 ± 0.068, I2 = 39.6) of QFR with FFR. The diagnostic performance was sensitivity 84% (95%CI: 77-90, I2 = 70.1), specificity 88% (95%CI: 84-91, I2 = 60.1); positive predictive value 80% (95%CI: 76-85, I2 = 33.4), and negative predictive value 95% (95%CI: 93-96, I2 = 75.9). CONCLUSIONS: Diagnostic performance of QFR was good with FFR as reference in this meta-analysis of high quality studies. QFR could provide an easy, safe, and cost-effective solution for functional evaluation of coronary artery stenosis.

Revascularization of coronary chronic total occlusions with subintimal tracking and reentry followed by deferred stenting: Experience from a high-volume referral center.

OBJECTIVES: To determine whether a variation of an abandoned antegrade percutaneous coronary intervention (PCI) technique, termed subintimal tracking and reentry (STAR), could be a safe and effective strategy to contend with complex coronary chronic total occlusions (CTO) when other strategies fail. BACKGROUND: Complex CTOs require advanced techniques such as the retrograde approach, which is associated with higher complication rates than antegrade strategies. METHODS: The medical records of 32 consecutive patients who underwent deferred stenting following STAR (DSS) between January 2015 and May 2017 at a high-volume referral center were retrospectively reviewed. The primary endpoint was technical success at the time of a second procedure following STAR-based balloon angioplasty, defined as successful stenting or the presence of Thrombolysis in Myocardial Infarction Study Group (TIMI) 3 flow with <50% residual stenosis if the vessel caliber was inappropriate for stenting. RESULTS: Of 781 CTO PCI procedures, STAR was performed in 45 (5.8%) and DSS in 32 (4.1%), constituting the analysis cohort. The median Japanese-CTO score was 2.5 [interquartile range (IQR) 1.0-3.0]. Median inter-procedure time was 2.4 months [1.7-3.3 months]. Technical success was achieved in 28 (88%) patients; 23 (72%) patients were treated with stents and 5 (16%) with balloon angioplasty alone. Combined complications included one clinical perforation, one MI, and one stent thrombosis. CONCLUSIONS: Deferred stenting after subintimal plaque modification via the STAR technique is a safe and effective strategy to contend with complex CTO lesions when other techniques are prohibitively high risk or have failed.