Quantitative flow ratio versus fractional flow reserve for Heart Team decision-making in multivessel disease: the randomised, multicentre DECISION QFR trial.

BACKGROUND: Vessel-level physiological data derived from pressure wire measurements are one of the important determinant factors in the optimal revascularisation strategy for patients with multivessel disease (MVD). However, these may result in complications and a prolonged procedure time. AIMS: The feasibility of using the quantitative flow ratio (QFR), an angiography-derived fractional flow reserve (FFR), in Heart Team discussions to determine the optimal revascularisation strategy for patients with MVD was investigated. METHODS: Two Heart Teams were randomly assigned either QFR- or FFR-based data of the included patients. They then discussed the optimal revascularisation mode (percutaneous coronary intervention [PCI] or coronary artery bypass grafting [CABG]) for each patient and made treatment recommendations. The primary endpoint of the trial was the level of agreement between the treatment recommendations of both teams as assessed using Cohen's kappa. RESULTS: The trial included 248 patients with MVD from 10 study sites. Cohen's kappa in the recommended revascularisation modes between the QFR and FFR approaches was 0.73 [95% confidence interval {CI} : 0.62-0.83]. As for the revascularisation planning, agreements in the target vessels for PCI and CABG were substantial for both revascularisation modes (Cohen's kappa=0.72 [95% CI: 0.66-0.78] and 0.72 [95% CI: 0.66-0.78], respectively). The team assigned to the QFR approach provided consistent recommended revascularisation modes even after being made aware of the FFR data (Cohen's kappa=0.95 [95% CI:0.90-1.00]). CONCLUSIONS: QFR provided feasible physiological data in Heart Team discussions to determine the optimal revascularisation strategy for MVD. The QFR and FFR approaches agreed substantially in terms of treatment recommendations.

Impact of Periprocedural Myocardial Injury on Long-Term Outcomes After Percutaneous Coronary Intervention Requiring Atherectomy.

The prognostic implications of cardiac troponin elevation after percutaneous coronary intervention (PCI) with atherectomy have not been established. The aim of this study was to investigate the incidence of periprocedural myocardial injury (PMI) and its association with cardiovascular events in patients with severely calcified lesions who underwent PCI with atherectomy. The study analyzed 346 patients (377 lesions) who underwent PCI with atherectomy between January 2018 and December 2021. Peak post-PCI high-sensitivity cardiac troponin (hs-cTn) was measured. The primary outcome was target lesion failure (TLF), a composite of cardiovascular death, target vessel myocardial infarction, and clinically driven target lesion revascularization. A lesion-based analysis was conducted to assess the association of PMI with TLF up to 5 years after PCI. Increase of hs-cTn was seen with 362 lesions (96%), and significant PMI, defined as hs-cTn increase ≥70 × upper reference limit, was seen with 83 lesions (22%). Significant PMI was associated with a significantly greater risk of TLF (adjusted hazard ratio 1.93, 95% confidence interval 1.12 to 3.30, p = 0.017), primarily driven by an increased risk of cardiovascular death (adjusted hazard ratio 5.29, 95% confidence interval 1.46 to 19.16, p = 0.011). In conclusion, hs-cTn increase was frequently observed in patients who underwent PCI with atherectomy, and significant PMI was associated with an increased risk of TLF and cardiovascular death.

Guideline-Directed Medical Therapy for Elderly Patients With Acute Myocardial Infarction Who Undergo Percutaneous Coronary Intervention　- Insights From a Retrospective Observational Study.

BACKGROUND: The efficacy of guideline-directed medical therapy (GDMT) in the elderly remains unclear. This study evaluated the impact of GDMT (aspirin or a P2Y12inhibitor, angiotensin-converting enzyme inhibitor or angiotensin receptor blocker, ß-blocker, and statin) at discharge on long-term mortality in elderly patients with acute myocardial infarction (AMI) who had undergone percutaneous coronary intervention (PCI).Methods and Results: Of 2,547 consecutive patients with AMI undergoing PCI in 2009-2020, we retrospectively analyzed 573 patients aged ≥80 years. The median follow-up period was 1,140 days. GDMT was prescribed to 192 (33.5%) patients at discharge. Compared with patients without GDMT, those with GDMT were younger and had higher rates of ST-segment elevation myocardial infarction and left anterior descending artery culprit lesion, higher peak creatine phosphokinase concentration, and lower left ventricular ejection fraction (LVEF). After adjusting for confounders, GDMT was independently associated with a lower cardiovascular death rate (hazard ratio [HR] 0.35; 95% confidence interval [CI] 0.16-0.81), but not with all-cause mortality (HR 0.77; 95% CI 0.50-1.18). In the subgroup analysis, the favorable impact of GDMT on cardiovascular death was significant in patients aged 80-89 years, with LVEF <50%, or with an estimated glomerular filtration rate ≥30 mL/min/1.73 m2. CONCLUSIONS: GDMT in patients with AMI aged ≥80 years undergoing PCI was associated with a lower cardiovascular death rate but not all-cause mortality.

Calcium Fracture After Intravascular Lithotripsy as Assessed With Optical Coherence Tomography.

BACKGROUND: Plaque characteristics associated with effective intravascular lithotripsy (IVL) treatment of calcification have not been investigated. This study identified calcified plaque characteristics that favor the use of IVL.Methods and Results: Optical coherence tomography (OCT) was performed in 16 calcified lesions in 16 patients treated with IVL and coronary stenting. Cross-sectional OCT images in 262 segments matched across pre-IVL, post-IVL, and post-stenting time points were analyzed. After IVL, 66 (25%) segments had calcium fracture. In multivariable analysis, calcium arc (odds ratio [OR] 1.22; 95% confidence interval [CI] 1.13-1.32; P<0.0001), superficial calcification (OR 6.98; 95% CI 0.07-55.57; P=0.0182), minimum calcium thickness (OR 0.66; 95% CI 0.51-0.86; P=0.0013), and nodular calcification (OR 0.24; 95% CI 0.08-0.70; P=0.0056) were associated with calcium fracture. After stenting, stent area was larger for segments with fracture (8.0 [6.9-10.6] vs. 7.1 [5.2-8.9] mm2; P=0.004). CONCLUSIONS: Post-IVL calcium fracture is more likely in calcified lesions with lower thickness, a larger calcium arc, superficial calcification, and non-nodular calcification, leading to a larger stent area.

Effect of Atherectomy on Lesion Preparation in Heavily Calcified Coronary Artery Disease.

Background: Percutaneous coronary intervention (PCI) of heavily calcified lesions remains challenging. This study examined whether calcified lesion preparation is better with an ablation-based than balloon-based technique. Methods and Results: Results of lesion preparations with and without atherectomy devices were compared in 121 patients undergoing optical coherence tomography (OCT)-guided PCI of heavily calcified lesions. Lesion preparation was performed with the ablation-based technique in 59 patients (atherectomy group) and with the balloon-based technique in 62 patients (balloon group). Lower grades of angiographic coronary dissections (National Heart, Lung, and Blood Institute [NHLBI] classification) occurred in the atherectomy than balloon group (atherectomy group: none, 33%; NHLBI A, 59%; B, 8%; C, 0%; D, 0%; balloon group: none, 1%; NHLBI A, 24%; B, 58%; C, 15%; D, 2%). On OCT, a large dissection was less common (49% vs. 90%; P<0.001) and calcium fractures were more frequent (75% vs. 18%; P<0.001) in the atherectomy than balloon group. In multivariable analyses, the ablation-based technique was associated with a lower grade of angiographic coronary dissection (adjusted odds ratio [aOR] 0.04; 95% confidence interval [CI] 0.01-0.12; P<0.001), a lower incidence of OCT-detected large dissection (aOR 0.09; 95% CI 0.03-0.30; P<0.001), and a higher incidence of OCT-detected calcium fracture (aOR 18.19; 95% CI 6.45-58.96; P<0.001). Conclusions: The ablation-based technique outperformed the balloon-based technique in the lesion preparation of heavily calcified lesions.

Impact of coronary plaque morphology on the precision of computational fractional flow reserve derived from optical coherence tomography imaging.

Background: Computational fractional flow reserve (FFR) was recently developed to expand the use of physiology-guided percutaneous coronary intervention (PCI). Nevertheless, current methods do not account for plaque composition. It remains unknown whether the numerical precision of computational FFR is impacted by the plaque composition in the interrogated vessels. Methods: This study is an observational, retrospective, cross-sectional study. Patients who underwent both optical coherence tomography (OCT) and FFR prior to intervention between August 2011 and October 2018 at Wakayama Medical University Hospital were included. All frames from OCT pullbacks were analyzed using a deep learning algorithm to obtain coronary plaque morphology including thin-cap fibroatheroma (TCFA), lipidic plaque volume (LPV), fibrous plaque volume (FPV), and calcific plaque volume (CPV). The interrogated vessels were stratified into three subgroups: the overestimation group with the numerical difference between the optical flow ratio (OFR) and FFR >0.05, the reference group with the difference ≥-0.05 and ≤0.05, and the underestimation group with the difference <-0.05. Results: In total 230 vessels with intermediate coronary artery stenosis from 193 patients were analyzed. The mean FFR was 0.82±0.10. Among them, 21, 179, and 30 vessels were in the overestimation, the reference, and the underestimation group, respectively. TCFA was higher in the underestimation group (60%) compared with reference (36.3%) and overestimation group (19%). Besides, it was not associated with numerical difference between OFR and FFR (NDOF) after multilevel linear regression. LPV was associated with NDOF as OFR underestimated FFR with -0.028 [95% confidence interval (CI): -0.047, -0.009] for every 100 mm3 increase in LPV. Conclusions: High lipid burden underestimates FFR when OFR is used to assess the hemodynamic importance of intermediate coronary artery stenosis. TCFA, FPV, and CPV were not independent predictors of NDOF.

Heart Team risk assessment with angiography-derived fractional flow reserve determining the optimal revascularization strategy in patients with multivessel disease: Trial design and rationale for the DECISION QFR randomized trial.

In patients with multivessel disease (MVD), functional information on lesions improves the prognostic capability of the SYNTAX score. Quantitative flow ratio (QFR®) is an angiography-derived fractional flow reserve (FFR) that does not require a pressure wire or pharmacological hyperemia. We aimed to investigate the feasibility of QFR-based patient information in Heart Teams' discussions to determine the optimal revascularization strategy for patients with MVD. We hypothesized that there is an acceptable agreement between treatment recommendations based on the QFR approach and recommendation based on the FFR approach. The DECISION QFR study is a prospective, multicenter, randomized controlled trial that will include patients with MVD who require revascularization. Two Heart Teams comprising cardiologists and cardiac surgeons will be randomized to select a revascularization strategy (percutaneous coronary intervention or coronary artery bypass graft) according to patient information either based on QFR or on FFR. All 260 patients will be assessed by both teams with reference to the anatomical and functional SYNTAX score/SYNTAX score II 2020 derived from the allocated physiological index (QFR or FFR). The primary endpoint of the trial is the level of agreement between the treatment recommendations of both teams, assessed using Cohen's κ. As of March 2022, the patient enrollment has been completed and 230 patients have been discussed in both Heart Teams. The current trial will indicate the usefulness of QFR, which enables a wireless multivessel physiological interrogation, in the discussions of Heart Teams to determine the optimal revascularization strategy for MVD.

Telecardiology in Rural Practice: Global Trends.

The management of cardiovascular diseases in rural areas is plagued by the limited access of rural residents to medical facilities and specialists. The development of telecardiology using information and communication technology may overcome such limitation. To shed light on the global trend of telecardiology, we summarized the available literature on rural telecardiology. Using PubMed databases, we conducted a literature review of articles published from January 2010 to December 2020. The contents and focus of each paper were then classified. Our search yielded nineteen original papers from various countries: nine in Asia, seven in Europe, two in North America, and one in Africa. The papers were divided into classified fields as follows: seven in tele-consultation, four in the telemedical system, four in the monitoring system, two in prehospital triage, and two in tele-training. Six of the seven tele-consultation papers reported the consultation from rural doctors to urban specialists. More reports of tele-consultations might be a characteristic of telecardiology specific to rural practice. Further work is necessary to clarify the improvement of cardiovascular outcomes for rural residents.

Prevalence of myocardial perfusion scintigraphy derived ischemia in coronary lesions with discordant fractional flow reserve and non-hyperemic pressure ratios.

BACKGROUND: Whether a coronary lesion with discordant fractional flow reserve (FFR) and non-hyperemic pressure ratios (NHPRs) causes myocardial ischemia remains unclear. This study investigates the prevalence of myocardial ischemia as assessed by myocardial perfusion scintigraphy (MPS) in coronary lesions with discordant FFR and instantaneous wave-free ratio (iFR), and, additionally, other NHPRs: resting full-cycle ratio (RFR), diastolic pressure ratio (dPR), and resting Pd/Pa. METHODS: A total of 484 coronary arteries in 295 patients with stable coronary artery disease that underwent MPS and invasive physiological pressure measurements were categorized into four groups (FFR+/NHPR+, FFR+/NHPR-, FFR-/NHPR+, and FFR-/NHPR-) using the respective cut-off values of FFR ≤ 0.80, iFR ≤ 0.89, RFR ≤ 0.89, dPR < 0.89, and Pd/Pa ≤ 0.92. The proportions of MPS-derived myocardial ischemia in a relevant myocardial territory were compared between the four groups. RESULTS: In total, 175 (36%), 61(13%), 35(7%) and 213(44%) vessels were classified into FFR+/iFR+, FFR+/iFR-, FFR-/iFR+ and FFR-/iFR- groups, respectively. The FFR+/iFR+ group had the highest proportion of MPS-derived ischemia (70%), followed by the FFR+/iFR- group (38%), the FFR-/iFR+ group (23%), and the FFR-/iFR- group (10%) (P < 0.001). Similar proportions of MPS-derived ischemia were found when RFR. (70%, 34%, 24%, and 10%, P < 0.001), dPR (70%, 38%, 26%, and 10%, P < 0.001), and Pd/Pa (70%, 31%, 22%, and 10%, P < 0.001) were used in place of iFR. CONCLUSIONS: The prevalence of MPS-derived myocardial ischemia in coronary lesions with discordance between FFR and NHPRs is lower than those with concordantly positive FFR and NHPRs, but higher than those with concordantly negative FFR and NHPRs.

Usefulness of optical coherence tomography with angiographic coregistration in the guidance of coronary stent implantation.

Optical coherence tomography (OCT)-angiography coregistration during stent implantation may be useful to avoid geographical mismatch and incomplete lesion coverage. Untreated lipid-rich plaque at stent edge is associated with subsequent stent edge restenosis. The present study sought to compare the frequency of untreated lipid-rich plaque at the stent edge between OCT-guided percutaneous coronary intervention (PCI) with and without OCT-angiography coregistration. We investigated 398 patients who underwent OCT-guided stent implantation (n = 198 in the coregistration group, and n = 200 in the no coregistration group). In OCT after PCI, untreated lipid-lich plaque was identified by the maximum lipid arc > 180˚ in the 5-mm stent edge segment. The PCI-targeted lesion characteristics and stent length were not different between the coregistration group and the no coregistration group. The frequency of untreated lipid-rich plaque in either proximal or distal stent edge segment was significantly lower in the coregistration group than in the no coregistration group (16% vs. 26%, P = 0.015). The frequency of stent-edge dissection (5% vs. 6%, P = 0.516) and untreated stenosis (2% vs. 3%, P = 0.724) was low and without significant differences between the two groups. In OCT-guided PCI, the use of OCT-angiography coregistration was associated with a reduced frequency of untreated lipid-rich plaque at stent edges. OCT-angiography coregistration has a positive impact on PCI results.

Near-infrared spectroscopy to predict microvascular obstruction after primary percutaneous coronary intervention.

BACKGROUND: Successful restoration of epicardial coronary artery patency by primary percutaneous coronary intervention (PPCI) for ST-elevation myocardial infarction (STEMI) does not always lead to adequate reperfusion at the microvascular level. AIMS: This study sought to investigate the association between lipid-rich coronary plaque identified by near-infrared spectroscopy combined with intravascular ultrasound (NIRS-IVUS) and microvascular obstruction (MVO) detected by cardiac magnetic resonance imaging (MRI) after PPCI for STEMI. METHODS: We investigated 120 patients with STEMI undergoing PPCI. NIRS-IVUS was used to measure the maximum lipid core burden index in 4 mm (maxLCBI4 mm) in the infarct-related lesions before PPCI. Delayed contrast-enhanced cardiac MRI was performed to evaluate MVO one week after PPCI. RESULTS: MVO was identified in 40 (33%) patients. MaxLCBI4 mm in the infarct-related lesion was significantly larger in the MVO group compared with the no-MVO group (median [interquartile range]: 745 [522-853] vs 515 [349-698], p<0.001). A multivariable logistic regression model showed that maxLCBI4 mm was an independent predictor of MVO (odds ratio: 24.7 [95% confidence interval: 2.5-248.0], p=0.006). Receiver operating characteristic curve analysis demonstrated that maxLCBI4 mm >600 was the optimal cut-off value to predict MVO (Youden index=0.44 and area under the curve=0.71) with a sensitivity of 75% and a specificity of 69%. CONCLUSIONS: Lipid content measured by NIRS in the infarct-related lesions was associated with the occurrence of MVO after PPCI in STEMI.

Optical coherence tomography detection of vulnerable plaques at high risk of developing acute coronary syndrome.

AIMS: The ability of optical coherence tomography (OCT) to detect plaques at high risk of developing acute coronary syndrome (ACS) remains unclear. The aim of this study was to evaluate the association between non-culprit plaques characterized as both lipid-rich plaque (LRP) and thin-cap fibroatheroma (TCFA) by OCT and the risk of subsequent ACS events at the lesion level. METHODS AND RESULTS: In 1378 patients who underwent OCT, 3533 non-culprit plaques were analysed for the presence of LRP (maximum lipid arc > 180°) and TCFA (minimum fibrous cap thickness < 65 µm). The median follow-up period was 6 years [interquartile range (IQR): 5-9 years]. Seventy-two ACS arose from non-culprit plaques imaged by baseline OCT. ACS was more often associated with lipidic plaques that were characterized as both LRP and TCFA vs. lipidic plaques that did not have these characteristics [33% vs. 2%, hazard ratio 19.14 (95% confidence interval: 11.74-31.20), P < 0.001]. The sensitivity and specificity of the presence of both LRP and TCFA for predicting ACS was 38% and 97%, respectively. A larger maximum lipid arc [1.01° (IQR: 1.01-1.01°)], thinner minimum fibrous cap thickness [0.99 µm (IQR: 0.98-0.99 µm)], and smaller minimum lumen area [0.78 mm2 (IQR: 0.67-0.90 mm2), P < 0.001] were independently associated with ACS. CONCLUSION: Non-culprit plaques characterized by OCT as both LRP and TCFA were associated with an increased risk of subsequent ACS at the lesion level. Therefore, OCT might be able to detect vulnerable plaques.

Impact of Optical Coherence Tomography Imaging on Decision-Making During Percutaneous Coronary Intervention in Patients Presented With Acute Coronary Syndromes.

BACKGROUND: Optical coherence tomography (OCT) provides valuable information to guide percutaneous coronary intervention (PCI) in acute coronary syndrome (ACS) regarding lesion preparation, stent sizing, and optimization. The aim of the present study was to compare lumen expansion of stent-treated lesions immediately after the procedure for ACS between OCT-guided PCI and angiography-guided PCI.Methods and Results:This study investigated stent-treated lesions immediately after PCI for ACS by using quantitative coronary angiography in 390 patients; 260 patients with OCT-guided PCI and 130 patients with angiography-guided PCI. Before stenting, the frequency of pre-dilatation and thrombus aspiration were not different between the OCT-guided and angiography-guided PCI groups. Stent diameter was significantly larger as a result of OCT-guided PCI (3.11±0.44 mm vs. 2.99±0.45 mm, P=0.011). In post-dilatation, balloon pressure-up (48% vs. 31%, P=0.001) and balloon diameter-up (33% vs. 6%, P<0.001) were more frequently performed in the OCT-guided PCI group. Minimum lumen diameter (2.55±0.35 mm vs. 2.13±0.50 mm, P<0.001) and acute lumen gain (2.18±0.54 mm vs. 1.72±0.63 mm, P<0.001) were significantly larger in the OCT-guided PCI group. Percent diameter stenosis (14±4% vs. 24±10%, P<0.001) and percent area stenosis (15±5% vs. 35±17%, P<0.001) were significantly smaller in the OCT-guided PCI group. CONCLUSIONS: OCT-guided PCI potentially results in larger lumen expansion of stent-treated lesions immediately after PCI in the treatment of ACS compared with angiography-guided PCI.

NIRS-IVUS for Differentiating Coronary Plaque Rupture, Erosion, and Calcified Nodule in Acute Myocardial Infarction.

OBJECTIVES: This study sought to investigate the ability of combined near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS) to differentiate plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN) in acute myocardial infarction (AMI). BACKGROUND: Most acute coronary syndromes occur from coronary thrombosis based on PR, PE, or CN. In vivo differentiation among PR, PE, and CN is a major challenge for intravascular imaging. METHODS: The study enrolled 244 patients with AMI who had a de novo culprit lesion in a native coronary artery. The culprit lesions were assessed by both NIRS-IVUS and optical coherence tomography (OCT). Maximum lipid core burden index in 4 mm (maxLCBI4mm) was measured by NIRS. Plaque cavity and convex calcium was detected by IVUS. The OCT diagnosis of PR (n = 175), PE (n = 44), and CN (n = 25) was used as a reference standard. RESULTS: In the development cohort, IVUS-detected plaque cavity showed a high specificity (100%) and intermediate sensitivity (62%) for identifying OCT-PR. IVUS-detected convex calcium showed a high sensitivity (93%) and specificity (100%) for identifying OCT-CN. NIRS-measured maxLCBI4mm was largest in OCT-PR (705 [interquartile range (IQR): 545 to 854]), followed by OCT-CN (355 [IQR: 303 to 478]) and OCT-PE (300 [IQR: 126 to 357]) (p < 0.001). The optimal cutoff value of maxLCBI4mm was 426 for differentiating between OCT-PR and -PE; 328 for differentiating between OCT-PE and -CN; and 579 for differentiating between OCT-PR and -CN. In the validation cohort, the NIRS-IVUS classification algorithm using plaque cavity, convex calcium, and maxLCBI4mm showed a sensitivity and specificity of 97% and 96% for identifying OCT-PR, 93% and 99% for OCT-PE, and 100% and 99% for OCT-CN, respectively. CONCLUSIONS: By evaluating plaque cavity, convex calcium, and maxLCBI4mm, NIRS-IVUS can accurately differentiate PR, PE, and CN.

Prognostic value of tissue-tracking mitral annular displacement by speckle-tracking echocardiography in asymptomatic aortic stenosis patients with preserved left ventricular ejection fraction.

BACKGROUND: Tissue-tracking mitral annular displacement (TMAD) by speckle-tracking echocardiography provides rapid and simple assessment of left ventricular (LV) longitudinal deformation. The purpose of this study was to evaluate the value of TMAD for the assessment of LV longitudinal deformation in patients with severe AS and preserved LV ejection fraction (LVEF). METHODS: We studied 44 patients with severe AS preserved and LVEF in whom TMAD was assessed. Using TMAD analysis software, the base-to-apex displacement of automatically defined mid-point of mitral annular line in four-chamber view was quickly assessed, and the percentage of its displacement to LV length at end-diastole (%TMAD) was calculated. We investigated the association between %TMAD and the cardiac events including appearance of symptom (dyspnea on exertion and hospitalization due to heart failure), decreased LVEF (< 50%), and cardiac death. RESULTS: During follow-up, the cardiac events developed in 16 (36%) of 44 patients. %TMAD was significantly impaired in patients with the cardiac events compared with those without the cardiac events (9.6 ± 1.9 vs 12.1 ± 2.6, p = 0.002). The cardiac events were predicted by %TMAD (HR 0.68, 95% CI 0.54-0.85; p = 0.0012). CONCLUSIONS: The present study suggests that TMAD easily and rapidly estimated by speckle-tracking echocardiography may be used as a simple method to predict occurrence of the cardiac events in asymptomatic severe AS patients with preserved LVEF.

Prevalence, Features, and Prognosis of Artery-to-Artery Embolic ST-Segment-Elevation Myocardial Infarction: An Optical Coherence Tomography Study.

Background The major underlying mechanisms contributing to acute coronary syndrome are plaque rupture, plaque erosion, and calcified nodule. Artery-to-artery embolic myocardial infarction (AAEMI) was defined as ST-segment-elevation myocardial infarction caused by migrating thrombus formed at the proximal ruptured plaque. The aim of this study was to investigate the prevalence and clinical features of AAEMI by using optical coherence tomography. Methods and Results This study retrospectively enrolled 297 patients with ST-segment-elevation myocardial infarction who underwent optical coherence tomography before percutaneous coronary intervention. Patients were divided into 4 groups consisting of plaque rupture, plaque erosion, calcified nodule, and AAEMI according to optical coherence tomography findings. The prevalence of AAEMI was 3.4%. The culprit vessel in 60% of patients with AAEMI was right coronary artery. Minimum lumen area at the culprit site was larger in AAEMI compared with plaque rupture, plaque erosion, and calcified nodule (4.0 mm2 [interquartile range (IQR), 2.2-4.9] versus 1.0 mm2 [IQR, 0.8-1.3] versus 1.0 mm2 [IQR, 0.8-1.2] versus 1.1 mm2 [IQR, 0.7-1.6], P<0.001). Lumen area at the rupture site was larger in patients with AAEMI compared with patients with plaque rupture (4.4 mm2 [IQR, 2.5-6.7] versus 1.5 mm2 [IQR, 1.0-2.4], P<0.001). In patients with AAEMI, the median minimum lumen area at the occlusion site was 1.2 mm2 (IQR, 1.0-2.1), 40% of them had nonstent strategy, and the 3-year major adverse cardiac event rate was 0%. Conclusions AAEMI is a rare cause for ST-segment-elevation myocardial infarction and has unique morphological features of plaque including larger lumen area at rupture site and smaller lumen area at the occlusion site.

Comparison of Optical Flow Ratio and Fractional Flow Ratio in Stent-Treated Arteries Immediately After Percutaneous Coronary Intervention.

BACKGROUND: Optical flow ratio (OFR) is a recently developed method for functional assessment of coronary artery disease based on computational fluid dynamics of vascular anatomical data from intravascular optical coherence tomography (OCT). The purpose of this study was to investigate the relationship between OFR and fractional flow reserve (FFR) in stent-treated arteries immediately after percutaneous coronary intervention (PCI).Methods and Results:The OFR and FFR were measured in 103 coronary arteries immediately after successful PCI with a stent. An increase in the OFR and FFR values within the stent was defined as in-stent ∆OFR and ∆FFR, respectively. The values of FFR and OFR were 0.89±0.06 and 0.90±0.06, respectively. OFR was highly correlated with FFR (r=0.84, P<0.001). OFR showed a good agreement with FFR, presenting small values of mean difference and root-mean-squared deviation (FFR-OFR: -0.01±0.04). In-stent ∆OFR showed a moderate correlation (r=0.69, P<0.001) and good agreement (in-stent ∆FFR - in-stent ∆OFR: 0.00±0.02) with in-stent ∆FFR. CONCLUSIONS: OFR showed a high correlation and good agreement with FFR in stent-treated arteries immediately after PCI.

Very late-phase vascular response after everolimus-eluting stent implantation assessed by optical coherence tomography.

Long-term safety of second generation drug-eluting stents (DES) has not yet been evaluated. We sought to evaluate the very late phase (> 3 years) vascular response after second generation everolimus-eluting stent (EES) as compared with first generation sirolimus-eluting stent (SES) by using optical coherence tomography (OCT). We examined the vascular response in 39 patients with a total of 55 DESs [31 EESs (mean 54 months after stenting) and 24 first generation SES (mean 66 months after stenting)] by OCT. The frequency of lesions with any malapposed stent struts (19% vs. 46%, p = 0.035) and evagination (6% vs. 42%, p = 0.002) was significantly lower. Segments with malapposed stent struts were significantly shorter (0.4 ± 0.9 mm vs. 1.9 ± 3.5 mm, p = 0.024), maximal malapposition area and malapposition volume were significantly smaller (0.26 ± 0.38 mm2 vs. 0.95 ± 1.54 mm2, p = 0.019, and 0.78 ± 1.35 mm3 vs. 6.22 ± 15.76 mm3, p = 0.016, respectively) in EES. Compared with first generation SES, second generation EES showed more favourable vascular responses at the very late phase.

Optical Coherence Tomography Comparison of Percutaneous Coronary Intervention Among Plaque Rupture, Erosion, and Calcified Nodule in Acute Myocardial Infarction.

BACKGROUND: Acute myocardial infarction (AMI) is caused by coronary plaque rupture (PR), plaque erosion (PE), or calcified nodule (CN). We used optical coherence tomography (OCT) to compare stent expansion immediately after primary percutaneous coronary intervention (PCI) in patients with AMI caused by PR, PE, or CN.Methods and Results:In all, 288 AMI patients were assessed by OCT before and immediately after PCI, performed with OCT guidance according to OPINION criteria for stent sizing and optimization. The frequency of OCT-identified PR (OCT-PR), OCT-PE, and OCT-CN was 172 (60%), 82 (28%), and 34 (12%), respectively. Minimum stent area was smallest in the OCT-CN group, followed by the OCT-PE and OCT-PR groups (mean [±SD] 5.20±1.77, 5.44±1.78, and 6.44±2.2 mm2, respectively; P<0.001), as was the stent expansion index (76±13%, 86±14%, and 87±16%, respectively; P=0.001). The frequency of stent malapposition was highest in the OCT-CN group, followed by the OCT-PR and OCT-PE groups (71%, 38%, and 27%, respectively; P<0.001), as was the frequency of stent edge dissection in the proximal reference (44%, 23%, and 10%, respectively; P<0.001). The frequency of tissue protrusion was highest in the OCT-PR group, followed by the OCT-PE and OCT-CN groups (95%, 88%, and 85%, respectively; P=0.036). CONCLUSIONS: Stent expansion was smallest in the OCT-CN group, followed by the OCT-PR and OCT-PE groups. Plaque morphology in AMI culprit lesions may affect stent expansion immediately after primary PCI.

Extent of the difference between microcatheter and pressure wire-derived fractional flow reserve and its relation to optical coherence tomography-derived parameters.

BACKGROUND: Although previous studies demonstrated that microcatheter-derived fractional flow reserve (mc-FFR) tends to overestimate lesion severity compared to pressure wire-derived FFR (pw-FFR), the clinical utility of mc-FFR remains obscure. The extent of differences between the two FFR systems and its relation to a lesion-specific parameter remain unknown. In this study, we sought to compare mc-FFR with pw-FFR and determine the lower and upper mc-FFR cut-offs predicting ischemic and non-ischemic stenosis, using an ischemic and a clinical FFR threshold of 0.75 and 0.80 as references, respectively. We further explored optical coherence tomography (OCT) parameters influencing the difference in FFR between the two systems. METHODS AND RESULTS: In this study, 44 target vessels with intermediate de novo coronary artery lesion in 36 patients with stable ischemic heart disease were evaluated with mc-FFR, pw-FFR and OCT. Bland-Altman plots for mc-FFR versus pw-FFR showed a bias of -0.04 for lower mc-FFR values compared to pw-FFR values. The mc-FFR cut-off values of 0.73 and 0.79 corresponded to the 0.75 ischemic pw-FFR and 0.80 clinical pw-FFR thresholds with high predictive values, respectively. The differences in the two FFR measurements (pw-FFR minus mc-FFR) were negatively correlated with OCT-derived minimum lumen area (MLA) (R = -0.359, p = 0.011). The OCT-derived MLA of 1.36 mm2 was a cut-off value for predicting the clinically significant difference between the two FFR measurements defined as >0.03. CONCLUSION: Mc-FFR is clinically useful when the specific cut-offs are applied. An OCT-derived MLA accounts for the clinically significant difference in FFR between the two systems.