Balloon pulmonary angioplasty under awake veno-arterial extracorporeal membrane oxygenation in a patient with class III obesity with chronic thromboembolic pulmonary hypertension complicated with multiple serious comorbidities.

Chronic thromboembolic pulmonary hypertension (CTEPH) is a chronic disease that can rapidly deteriorate into circulatory collapse when complicated by comorbidities. We herein describe a case involving a 43-year-old woman with class III obesity (body mass index of 63 kg/m2) and severe CTEPH associated with total occlusion of the left main pulmonary artery who subsequently developed circulatory collapse along with multiple comorbidities, including acute kidney injury, pulmonary tuberculosis, and catastrophic antiphospholipid syndrome. The patient was successfully treated with two sessions of rescue balloon pulmonary angioplasty with veno-arterial extracorporeal membrane oxygenation (V-A ECMO) support under local anesthesia without sedation, at cannulation and during the V-A ECMO run, to avoid invasive mechanical ventilation. This case suggests the potential usefulness of rescue balloon pulmonary angioplasty under awake V-A ECMO support for rapidly deteriorating, inoperable CTEPH in a patient with class III obesity complicated with multiple comorbidities.

Clinical outcomes of acute myocardial infarction arising from non-lipid-rich plaque determined by NIRS-IVUS.

Acute myocardial infarction (AMI) can rarely arise from non-lipid-rich coronary plaques. This study sought to compare the clinical outcomes after percutaneous coronary intervention (PCI) between AMI showing maximum lipid-core burden index in 4 mm (maxLCBI4mm) < 400 and ≥ 400 in the infarct-related lesions assessed by near-infrared spectroscopy-intravascular ultrasound (NIRS-IVUS). We investigated 426 AMI patients who underwent NIRS-IVUS in the infarct-related lesions before PCI. Major adverse cardiovascular events (MACE) were defined as the composite of cardiac death, non-fatal MI, clinically driven target lesion revascularization (TLR), clinically driven non-TLR, and congestive heart failure requiring hospitalization. 107 (25%) patients had infarct-related lesions of maxLCBI4mm < 400, and 319 (75%) patients had those of maxLCBI4mm ≥ 400. The maxLCBI4mm < 400 group had a younger median age at onset (68 years [IQR: 57-78 years] vs. 73 years [IQR: 64-80 years], P = 0.007), less frequent multivessel disease (39% vs. 51%, P = 0.029), less frequent TIMI flow grade 0 or 1 before PCI (62% vs. 75%, P = 0.007), and less frequent no-reflow immediately after PCI (5% vs. 11%, P = 0.039). During a median follow-up period of 31 months [IQR: 19-48 months], the frequency of MACE was significantly lower in the maxLCBI4mm < 400 group compared with the maxLCBI4mm ≥ 400 group (4.7% vs. 17.2%, P = 0.001). MaxLCBI4mm < 400 was an independent predictor of MACE-free survival at multivariable analysis (hazard ratio: 0.36 [confidence interval: 0.13-0.98], P = 0.046). MaxLCBI4mm < 400 measured by NIRS in the infract-related lesions before PCI was associated with better long-term clinical outcomes in AMI patients.

Balloon Pulmonary Angioplasty for Takayasu Arteritis and Peripheral Pulmonary Artery Stenosis Mimicking Chronic Thromboembolic Pulmonary Hypertension.

Balloon pulmonary angioplasty (BPA) has been reported to be effective and safe to an acceptable level in patients with distal-type, inoperable chronic thromboembolic pulmonary hypertension (CTEPH), resulting in improved long-term survival. However, evidenced treatment options and strategy including medical therapy of antithrombotic therapy, glucocorticoids, immunosuppressants, and pulmonary hypertension (PH)-specific therapies are scarce in patients with significant PH and right heart failure associated with Takayasu arteritis and peripheral pulmonary artery stenosis, both of which mimic CTEPH. Moreover, there has been still concern on safety and lack of established methodology in performing BPA for these conditions. In this report, we would like to review recent publications including several case reports and discuss the efficacy, safety, and suitable methods of BPA in this population.

Target Lesion Lipid Content Detected by Near-Infrared Spectroscopy After Stenting and the Risk of Subsequent Target Lesion Failure.

[Figure: see text].

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.

Retrospective Comparison of Long-Term Clinical Outcomes Between Percutaneous Coronary Intervention and Medical Therapy in Stable Coronary Artery Disease With Gray Zone Fractional Flow Reserve　- COMFORTABLE Retrospective Study.

BACKGROUND: A fractional flow reserve (FFR) between 0.75 and 0.80 constitutes a "gray zone" for clinical decision-making in coronary artery disease. We compared long-term outcomes of percutaneous coronary intervention (PCI) using drug-eluting stents vs. medical therapy for coronary stenosis with gray zone FFR. Methods and Results: We retrospectively investigated the clinical outcomes of 263 patients with gray zone FFR: 78 patients in the PCI group and 185 patients in the medical therapy group. During a median follow-up of 3.7 years, the frequency of target vessel failure (TVF, defined as a composite of cardiac death, myocardial infarction [MI], or ischemia-driven target vessel revascularization [TVR]) was significantly lower in the PCI group compared with the medical therapy group (6% vs. 19%, hazard ratio [HR]:0.33, 95% confidence interval [CI]: 0.13-0.84, P=0.008). The frequency of a composite of cardiac death or MI was not different between the 2 groups (1% vs. 2%, HR: 0.61, 95% CI: 0.07-5.49, P=0.645). The frequency of ischemia-driven TVR was significantly lower in the PCI group compared with the medical therapy group (5% vs. 18%, HR: 0.28, 95% CI: 0.10-0.79, P=0.005). CONCLUSIONS: In patients with gray zone FFR, compared with medical therapy, PCI decreased the frequency of TVF, which was mainly driven by a reduction in the frequency of angina or myocardial ischemia without any difference in the frequency of cardiac death or MI.

Quantitative flow ratio and instantaneous wave-free ratio for the assessment of the functional severity of intermediate coronary artery stenosis.

OBJECTIVE: Quantitative flow ratio (QFR) is a novel physiological index of the severity of coronary stenosis. The aim of the present study was to investigate the relationship between QFR and the instantaneous wave-free ratio (iFR). PATIENTS AND METHODS: We analyzed contrast-flow QFR, iFR, and fractional flow reserve (FFR) in 100 coronary arteries with intermediate stenosis. RESULTS: There was a high correlation (r=0.71, P<0.001) and a good agreement (mean difference: -0.09±0.11) between QFR and iFR. Both QFR and iFR were correlated significantly with FFR (r=0.89, P<0.001 and r=0.76, P<0.001, respectively). The mean absolute difference between FFR and QFR was significantly smaller than that between FFR and iFR (-0.01±0.07 vs. -0.08±0.09, P<0.001). The diagnostic accuracy of QFR less than or equal to 0.80 for predicting FFR less than or equal to 0.80 was numerically higher than that of iFR less than or equal to 0.89 for predicting FFR less than or equal to 0.80 [QFR: 94% (95% confidence interval: 85-97%) vs. iFR: 74% (95% confidence interval: 65-81%)]. CONCLUSION: QFR was correlated highly with iFR as well as FFR. Like FFR and iFR, QFR might be reliable for assessing the physiological severity of coronary stenosis in the angiographic intermediate lesions.

The relationship between timing of prasugrel pretreatment and in-stent thrombus immediately after percutaneous coronary intervention for acute coronary syndrome: an optical coherence tomography study.

The optimal timing of pretreatment with prasugrel in percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) is unclear. We used optical coherence tomography (OCT) to compare in-stent thrombus volume immediately after PCI between the administration of low-dose prasugrel (20 mg loading dose) at the time of diagnosis of ACS (early prasugrel: n = 34) and the administration of low-dose prasugrel immediately after diagnostic angiography prior to PCI for ACS (late prasugrel: n = 56). The durations between the administration of prasugrel and OCT in the early prasugrel group and late prasugrel group were 5.1 ± 6.5 and 0.9 ± 0.7 h, respectively (p < 0.001). OCT detected thrombus/plaque protrusion in all stented segments. In-stent thrombus/plaque protrusion volume (2.92 ± 1.96 vs. 6.48 ± 4.97 mm3, p < 0.001), mean in-stent thrombus/plaque protrusion area (0.13 ± 0.07 vs. 0.29 ± 0.23 mm2, p < 0.001) and maximum in-stent thrombus/plaque protrusion area (0.70 ± 0.36 vs. 1.06 ± 0.56 mm2, p < 0.001) were significantly smaller in the early prasugrel group as compared with the late prasugrel group. The administration of prasugrel at the time of diagnosis of ACS was associated with significantly reduced in-stent thrombus/plaque protrusion immediately after PCI as compared with the administration of prasugrel after the coronary angiography prior to PCI.

Diagnostic Accuracy of Quantitative Flow Ratio for Assessing Myocardial Ischemia in Prior Myocardial Infarction.

BACKGROUND: A novel index of the functional severity of coronary stenosis, quantitative flow ratio (QFR), may not consider the amount of viable myocardium in prior myocardial infarction (MI) because QFR is calculated from 3D quantitative coronary angiography.Methods and Results:We analyzed QFR (fixed-flow QFR [fQFR] and contrast-flow QFR [cQFR]) and fractional flow reserve (FFR) in prior-MI-related coronary arteries (n=75) and non-prior-MI-related coronary arteries (n=75). Both fQFR and cQFR directly correlated with FFR in the prior-MI-related coronary arteries (fQFR: r=0.84, P<0.001; and cQFR: r=0.88, P<0.001) and the non-prior-MI-related coronary arteries (fQFR: r=0.91, P<0.001; and cQFR: r=0.94, P<0.001). fQFR was significantly smaller than FFR in the prior-MI-related coronary arteries (0.73±0.14 vs. 0.79±0.11, P=0.002), but there was no significant difference between fQFR and FFR in the non-prior-MI-related coronary arteries. The value of cQFR minus FFR was significantly lower in the prior-MI-related coronary arteries compared with the non-prior-MI-related coronary arteries (-0.02±0.06 vs. 0.00±0.04, P=0.010). The diagnostic accuracy of fQFR ≤0.8 and cQFR ≤0.8 for predicting FFR ≤0.80 was numerically lower in the prior-MI-related coronary arteries compared with the non-prior-MI-related coronary arteries (fQFR: 77% vs. 87%; and cQFR: 87% vs. 92%). CONCLUSIONS: When FFR is used as the gold standard, the accuracy of QFR for assessing the functional severity of coronary stenosis might be reduced in the prior-MI-related coronary arteries compared with non-prior-MI-related coronary arteries.

Effect of Early Pitavastatin Therapy on Coronary Fibrous-Cap Thickness Assessed by Optical Coherence Tomography in Patients With Acute Coronary Syndrome: The ESCORT Study.

OBJECTIVES: The aim of the present study was to assess the effect of early statin therapy on fibrous-cap thickness in coronary plaques of patients with acute coronary syndrome (ACS) by using optical coherence tomography. BACKGROUND: Statins can contribute to the stabilization of coronary plaques. METHODS: This is a prospective, randomized, active-controlled, single-center study. Patients with ACS and untreated dyslipidemia were enrolled and randomly allocated (ratio 1:1) to either the early statin group (received pitavastatin 4 mg/day from baseline) or the late statin group (received pitavastatin 4 mg/day from 3 weeks after the baseline). Optical coherence tomography was performed at baseline, 3-week, and 36-week follow-up to assess nonculprit coronary plaques in 53 patients. RESULTS: Between baseline and 3-week follow-up, fibrous-cap thickness increased in the early statin group (140 µm [interquartile range (IQR):120 to 170 µm] to 160 µm [IQR: 130 to 190 µm]; p = 0.017), but decreased in the late statin group (135 µm [IQR: 110 to 183 µm] to 130 µm [IQR: 108 to 160 µm]; p = 0.020). The percentage of increase in fibrous-cap thickness between baseline and 3-week follow-up was significantly greater in the early statin group compared with the late statin group (8.3% [IQR: 0.0% to 21.4%] vs. -5.8% [IQR: -16.0% to 0.0%]; p < 0.001). Between baseline and 36-week follow-up, fibrous-cap thickness increased comparably in the 2 groups. CONCLUSIONS: Early therapy with pitavastatin 4 mg/day for patients with ACS provided an increase in fibrous-cap thickness in coronary plaques during the first 3 weeks of follow-up and a further increase during 36 weeks of follow-up. The study was registered with UMIN Clinical Trial Registry (Effect of PitavaStatin on Coronary Fibrous-cap Thickness-Assessment by Fourier-Domain Optical CoheRence Tomography [ESCORT]; UMIN000002678).

Automated lipid-rich plaque detection with short wavelength infra-red OCT system.

Aims: Vulnerable coronary plaque is characterized by a large lipid core. Although commercially-available optical coherence tomography (OCT) systems use near-infrared light at 1300 nm wavelength, lipid shows characteristic absorption at 1700 nm. Therefore, we developed a novel, short wavelength infra-red, spectroscopic, spectral-domain OCT. The aim of the present study is to evaluate the accuracy of short wavelength (1700 nm) infra-red optical coherence tomography (SWIR-OCT) for identification of lipid tissue within coronary plaques. Methods and results: Twenty-three coronary arteries from 10 cadavers were imaged at physiological pressure with 2.7 Fr SWIR-OCT catheter. When a blood-free image was observed, the SWIR-OCT imaging core was withdrawn at a rate of 20 mm/s using an automatic pullback device. SWIR-OCT images were acquired at 94 frames/s and digitally archived. SWIR-OCT generated grey-scale cross sectional images and colour tissue maps of all of the plaque by using a lipid analysis algorithm. After SWIR-OCT imaging, the arteries were pressure-fixed, sliced by cryostat and stained with Oil Red O, and then corresponding histology was collected in matched images. Regions of interest, selected from histology, were 117 lipidic and 34 fibrotic/calcified regions. SWIR-OCT showed high sensitivity (89%) and specificity (92%) for identifying lipid tissue within coronary plaques. The positive predictive value and negative predictive value were 97% and 74%, respectively. Conclusion: SWIR-OCT accurately identified lipid tissue in coronary autopsy specimens. This new technique may hold promise for identifying histopathological features of coronary plaque at risk for rupture.

Prognosis of spontaneous coronary artery dissection treated by percutaneous coronary intervention with optical coherence tomography.

BACKGROUND: Although about half of patients with spontaneous coronary artery dissection (SCAD) face ongoing necrosis, conservative therapy is recommended due to a high complication rate in angiography-guided percutaneous coronary intervention (PCI). The aim of this study was to investigate clinical outcomes of SCAD treated by optical coherence tomography (OCT)-guided PCI. METHODS: This study consisted of consecutive 306 patients with acute coronary syndrome (ACS) who underwent OCT-guided PCI. Based on the culprit lesion morphology by OCT, patients were assigned to four groups: a SCAD group, a plaque rupture (PR) group, a calcified nodule (CN) group, and an undetermined etiology (UE) group. Successful PCI was defined as thrombolysis in myocardial infarction flow grade 3 in final angiography without any complications. Primary endpoint was defined as occurrence rate of major adverse cardiac events (MACE) including cardiac death, myocardial infarction, and unstable angina pectoris. RESULTS: OCT revealed 12 SCADs, 149 PRs, 16 CNs, and 129 UEs, respectively. No significant difference was observed in the success rate of PCI (SCAD 91.7%, PR 85.2%, CN 81.2%, UE 86.8%, p=0.88), while wire repositioning was needed in 2 SCAD cases (p<0.01). The mean follow-up periods were 17.1±13.3 months. No significant difference was observed in MACE among the groups (p=0.56). CONCLUSIONS: The clinical outcomes of OCT-guided PCI for SCAD were favorable, as well as those for other ACS etiologies. OCT-guided PCI could become a therapeutic option for SCAD compromised with ongoing necrosis.

Impact of Plaque Rupture Detected by Optical Coherence Tomography on Transmural Extent of Infarction After Successful Stenting in ST-Segment Elevation Acute Myocardial Infarction.

OBJECTIVES: The aim of the present study was to investigate the association between plaque rupture (PR) assessed by optical coherence tomography (OCT), and the transmural extent of infarction (TEI) assessed by contrast-enhanced cardiac magnetic resonance imaging (CE-CMR) in ST-segment elevation myocardial infarction (STEMI) patients after primary percutaneous coronary intervention (PCI). BACKGROUND: PR is associated with larger infarct size as assessed by cardiac enzymes in STEMI patients. CE-CMR is a favorable method to assess TEI, which can predict the prognosis of STEMI patients. METHODS: First, STEMI patients with primary PCI within 12 h after onset were enrolled and divided into 2 groups according to presence (n = 71) or absence (n = 32) of PR at the culprit lesion as assessed by pre-intervention OCT. CE-CMR was performed at 1 week after primary PCI. RESULTS: The frequency of no-reflow phenomenon (37% vs. 16%; p = 0.032) and distal embolization (24% vs. 6%; p = 0.032) was significantly higher in the rupture group compared with the non-rupture group. TEI grade was significantly greater in the rupture group (28% vs. 15% in grade 3 and 45% vs. 13% in grade 4; p < 0.001). Microvascular obstruction was more frequently seen in the rupture group (39% vs. 19%; p = 0.039). Multivariate analysis identified PR (odds ratio: 6.60, 95% confidence interval: 2.19 to 21.69; p < 0.001) and no statin use before admission (odds ratio: 3.37, 95% confidence interval: 1.06 to 11.19; p = 0.039) as independent predictors of TEI grade 3 or 4. CONCLUSIONS: PR as assessed by OCT is associated with greater TEI as assessed by CE-CMR in STEMI patients after primary PCI.

Reduction of in-stent thrombus immediately after percutaneous coronary intervention by pretreatment with prasugrel compared with clopidogrel: An optical coherence tomography study.

BACKGROUND: Prasugrel is a new-generation thienopyridine antiplatelet agent that provides more consistent and prompt platelet inhibition than clopidogrel. The aim of this study was to compare in-stent thrombus inhibition effect of pretreatment with prasugrel and clopidogrel by using optical coherence tomography (OCT) immediately after percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS). METHODS: We performed OCT immediately after PCI in 108 ACS patients pretreated with either prasugrel (n=51) or clopidogrel (n=57). OCT detected thrombus/plaque protrusion in all stented segments. RESULTS: Although stent volume (190.4±119.1mm3 vs. 189.4±95.8mm3, p=0.961), mean stent area (6.9±2.9mm2 vs. 7.1±2.0mm2, p=0.772), and minimum stent area (5.6±2.7mm2 vs. 5.4±1.7mm2, p=0.554) were not different between the two groups, in-stent thrombus/plaque protrusion volume (1.8±2.9mm3 vs. 4.5±5.3mm3, p=0.002), mean in-stent thrombus/plaque protrusion area (0.1±0.1mm2 vs. 0.2±0.2mm2, p=0.005), and maximum in-stent thrombus/plaque protrusion area (0.5±0.7mm2 vs. 0.8±0.6mm2, p=0.007) were significantly smaller in the prasugrel group compared with the clopidogrel group. CONCLUSIONS: Pretreatment with prasugrel was associated with significantly reduced in-stent thrombus/plaque protrusion immediately after PCI for ACS compared with that with clopidogrel.

Effects of intravenous bolus injection of nicorandil on renal artery flow velocity assessed by color Doppler ultrasound.

BACKGROUND: Previous animal studies have shown that a potassium channel opener, nicorandil, provokes vasodilation in renal microvasculature and increases renal blood flow. We conducted a clinical study that aimed to evaluate the effect of nicorandil on renal artery blood flow in comparison with nitroglycerin by using color Doppler ultrasound. METHODS: The present study enrolled 40 patients with stable coronary artery disease who had no renal arterial stenosis and renal parenchymal disease. The patients received intravenous administration of nicorandil (n=20) or nitroglycerin (n=20). Before and after the administration, renal artery blood flow velocity was measured by color-guided pulsed-wave Doppler. RESULTS: The peak-systolic, end-diastolic, and mean renal artery blood flow velocities before the administration were not different between the nicorandil group and the nitroglycerin group. The peak-systolic (79±15cm/s to 99±21cm/s, p<0.001; and 78±19cm/s to 85±19cm/s, p=0.004), end-diastolic (22±5cm/s to 28±8cm/s, p<0.001; and 24±6cm/s to 26±6cm/s, p=0.005) and mean (41±6cm/s to 49±9cm/s, p<0.001; and 43±9cm/s to 45±9cm/s, p=0.009) renal artery flow velocities increased significantly in either group. The nominal changes in the peak-systolic (20±10cm/s vs. 7±8cm/s, p<0.001), end-diastolic (5±4cm/s vs. 2±3cm/s, p=0.001), and mean (8±5cm/s vs. 2±2cm/s, p<0.001) renal artery blood flow velocities were significantly greater in the nicorandil group compared with the nitroglycerin group. CONCLUSION: Intravenous nicorandil increased renal artery blood flow velocity in comparison with nitroglycerin. Nicorandil has a significant effect on renal hemodynamics.

Automated characterisation of lipid core plaques in vivo by quantitative optical coherence tomography tissue type imaging.

AIMS: Qualitative criteria for plaque tissue characterisation by OCT are well established, but quantitative methods lack systematic validation in vivo. High optical attenuation coefficient µt has been associated with unstable plaque features, such as lipid core. The purpose of this study was to validate optical coherence tomography (OCT) attenuation imaging for tissue characterisation in vivo, specifically to detect lipid core in coronary atherosclerotic plaques, and to evaluate quantitatively the ability of OCT attenuation imaging to differentiate thin-cap (TCFA) and thick-cap fibroatheroma (FA). METHODS AND RESULTS: We prospectively enrolled 85 patients undergoing imaging of a native coronary segment by both OCT and near-infrared spectroscopy and intravascular ultrasound (NIRS-IVUS). Ninety-eight NIRS-positive 4 mm plaque segments were selected and matched to the OCT data. Two experienced OCT readers classified the plaque type using OCT criteria. A cap thickness of 65 µm was used to differentiate TCFA and FA. We computed an index of plaque attenuation (IPA) in the 4 mm blocks, and assessed the association of this index with plaque type. IPA differentiated between TCFA and FA (AUC=0.82 in ROC analysis; p<0.0001). LCBI was numerically, but not significantly, higher in TCFA compared to FA (p=0.097). CONCLUSIONS: IPA is an unbiased reproducible measure of tissue optical properties. The fraction of pixels with attenuation coefficient ≥11 mm-1 can identify TCFA.

Local Matrix Metalloproteinase 9 Level Determines Early Clinical Presentation of ST-Segment-Elevation Myocardial Infarction.

OBJECTIVE: Early clinical presentation of ST-segment-elevation myocardial infarction (STEMI) and non-ST-segment-elevation myocardial infarction affects patient management. Although local inflammatory activities are involved in the onset of MI, little is known about their impact on early clinical presentation. This study aimed to investigate whether local inflammatory activities affect early clinical presentation. APPROACH AND RESULTS: This study comprised 94 and 17 patients with MI (STEMI, 69; non-STEMI, 25) and stable angina pectoris, respectively. We simultaneously investigated the culprit lesion morphologies using optical coherence tomography and inflammatory activities assessed by shedding matrix metalloproteinase 9 (MMP-9) and myeloperoxidase into the coronary circulation before and after stenting. Prevalence of plaque rupture, thin-cap fibroatheroma, and lipid arc or macrophage count was higher in patients with STEMI and non-STEMI than in those with stable angina pectoris. Red thrombus was frequently observed in STEMI compared with others. Local MMP-9 levels were significantly higher than systemic levels (systemic, 42.0 [27.9-73.2] ng/mL versus prestent local, 69.1 [32.2-152.3] ng/mL versus poststent local, 68.0 [35.6-133.3] ng/mL; P<0.01). Poststent local MMP-9 level was significantly elevated in patients with STEMI (STEMI, 109.9 [54.5-197.8] ng/mL versus non-STEMI: 52.9 [33.0-79.5] ng/mL; stable angina pectoris, 28.3 [14.2-40.0] ng/mL; P<0.01), whereas no difference was observed in the myeloperoxidase level. Poststent local MMP-9 and the presence of red thrombus are the independent determinants for STEMI in multivariate analysis. CONCLUSIONS: Local MMP-9 level could determine the early clinical presentation in patients with MI. Local inflammatory activity for atherosclerosis needs increased attention.