Tissue characteristics of residual lesion in patients with acute coronary syndrome caused by plaque rupture versus plaque erosion: a single-center, retrospective, observational study.

Patients with acute coronary syndrome (ACS), frequently caused by plaque rupture (PR), often have vulnerable plaques in residual lesions as well as in culprit lesions. However, whether this occurs in patients with plaque erosion (PE) as well is unknown. We retrospectively analyzed the data of 88 patients with ACS who underwent both optimal coherence tomography (OCT) and intravascular ultrasound (IVUS). Based on plaque morphology of the culprit lesions identified using OCT, patients were classified into PE (n=23) and PR (n=35) groups. The tissue characteristics of residual lesions evaluated using integrated backscatter IVUS were compared between both groups after percutaneous coronary intervention. The PE group had a significantly lower percent lipid volume and a higher percent fibrous volume than the PR group (35.0±17.8% vs 49.2±13.4%, p<0.001; 63.2±17.1% vs 50.3±13.1%, p=0.002, respectively). Receiver operating characteristic curve analysis revealed that percent lipid volume in the residual lesions was a significant discriminant factor in estimating the plaque morphology of the culprit lesion (optimal cut-off value, <43.5%; sensitivity and specificity values were 73.9% and 68.6%, respectively). In conclusion, patients with PE had a significantly lower percent lipid volume and a significantly higher percent fibrous volume in the residual lesions than those with PR, suggesting that the nature of coronary plaques in patients with PE is different from that of those with PR.

Differential Impact of Renal Function on the Diagnostic Performance of Resting Full-Cycle Ratio in Patients With Renal Dysfunction.

Background: Physiological assessments using fractional flow reserve (FFR) and resting full-cycle ratio (RFR) have been recommended for revascularization decision making. Previous studies have shown a 20% rate of discordance between FFR and RFR. In this context, the correlation between RFR and FFR in patients with renal dysfunction remains unclear. This study examined correlations between RFR and FFR according to renal function. Methods and Results: In all, 263 consecutive patients with 370 intermediate lesions were enrolled in the study. Patients were classified into 3 groups according to renal function: Group 1, estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2; Group 2, 30 mL/min/1.73 m2≤eGFR<60 mL/min/1.73 m2; Group 3, eGFR <30 mL/min/1.73 m2. The discordance between FFR and RFR was assessed using known cut-off values for FFR (≤0.80) and RFR (≤0.89). Of the 370 lesions, functional significance with FFR was observed in 154 (41.6%). RFR was significantly correlated with FFR in all groups (Group 1, R2=0.62 [P<0.001]; Group 2, R2=0.67 [P<0.001]; Group 3, R2=0.46 [P<0.001]). The rate of discordance between RFR and FFR differed significantly among the 3 groups (Group 1, 18.8%; Group 2, 18.5%; Group 3, 42.9%; P=0.02). Conclusions: The diagnostic performance of RFR differed based on renal function. A better understanding of the clinical factors contributing to FFR/RFR discordance, such as renal function, may facilitate the use of these indices.

Diagnostic Performance of High-Resolution Intravascular Ultrasound for Abnormal Post-Stent Findings After Stent Implantation　- A Comparison Study Between High-Resolution Intravascular Ultrasound and Optical Coherence Tomography.

BACKGROUND: High-resolution intravascular ultrasound (HR-IVUS) is the most recently developed IVUS technology, which allows the detailed assessment of intravascular structures. The aim of this study was to evaluate the diagnostic performance of HR-IVUS in the detection of abnormal post-stent findings.Methods and Results:Patients with acute coronary syndrome underwent both HR-IVUS and optical coherence tomography (OCT) for post-stent evaluations. Quantitative measurements for stented segments and qualitative assessments for abnormal post-stent findings (stent edge dissection, intrastent tissue protrusion, and incomplete stent apposition [ISA]) were performed. Forty-seven patients underwent both HR-IVUS and OCT after stent implantation. HR-IVUS identified a larger minimal lumen area and a larger minimal lumen diameter than OCT (6.66±1.98 mm2vs. 5.61±1.79 mm2and 2.87±0.42 mm vs. 2.63±0.43 mm, respectively; both P<0.001). The sensitivity of HR-IVUS for the identification of stent edge dissection, intrastent tissue protrusion, and ISA were 20.0%, 48.9%, and 27.2%, respectively. CONCLUSIONS: In terms of post-stent evaluation, the diagnostic performance of HR-IVUS remains insufficient. Abnormal post-stent findings might be underestimated when performing HR-IVUS due to its low sensitivity.

Independent predictors of discordance between the resting full-cycle ratio and fractional flow reserve.

The resting full-cycle ratio (RFR), a novel resting index, is well correlated with and shows good diagnostic accuracy to the fractional flow reserve (FFR). However, discordance results between the RFR and FFR have been observed to occur in about 20% of cases. This study aimed to clarify the prevalence and factors of discordant results between the RFR and FFR through a direct comparison of these values in daily clinical practice. A total of 220 intermediate coronary lesions of 156 consecutive patients with RFR and FFR measurements were allocated to four groups according to RFR and FFR cutoff values. We compared the angiographic, clinical, and hemodynamic variables among the groups. Discordant results between the RFR and FFR were observed in 19.6% of vessels, and the proportion of discordant results was significantly higher in the left main trunk and left anterior descending artery (LM + LAD) than in non-LAD vessels (25.2% vs. 12.3%, p = 0.006). In the multivariable regression analysis, LM + LAD location, hemodialysis, and peripheral artery disease were associated with a low RFR among patients with a high FFR. Conversely, the absence of diabetes mellitus and the presence of higher hemoglobin levels were associated with a higher RFR among patients with a low FFR. Specific angiographic and clinical characteristics such as LM + LAD location, hemodialysis, peripheral artery disease, and absence of diabetes mellitus and anemia can be independent predictors of physiologic discordance between the RFR and FFR.

Impact of antiplatelet therapy on tissue prolapse at super acute phase after stenting: serial OCT study in acute coronary syndrome patients.

Although drug-eluting stents have improved clinical outcomes, percutaneous coronary intervention (PCI) for acute coronary syndrome (ACS) remains a challenging procedure in terms of thrombus management. A new-generation P2Y12 receptor inhibitor, prasugrel, provides more rapid and potent antiplatelet action compared with clopidogrel. Prasugrel achieved significant reduction of ischemic events compared with clopidogrel in ACS. The aim of this optical coherence tomography (OCT) study was to evaluate temporal changes in tissue prolapse after stenting under different antiplatelet regimens (aspirin plus prasugrel or clopidogrel) in ACS patients. A total of 119 ACS patients were randomized to either prasugrel or clopidogrel at the time of PCI. OCT analysis was available in 119 patients at baseline (just after stenting), 77 patients at 2 weeks, and 62 patients at 4 months after stenting. Cross-sectional analysis for every 1 mm was performed at in-stent and adjacent reference segment. Tissue prolapse area was calculated by lumen area minus stent area within the stented segment. Baseline patient and procedural characteristics were not different between the prasugrel and clopidogrel groups. Tissue prolapse area was significantly lower in the prasugrel compared with the clopidogrel group after stenting (0.24 ± 0.23 vs. 0.36 ± 0.23 mm2, p = 0.003) and at 2 weeks (0.11 ± 0.13 vs. 0.19 ± 0.16 mm2, p = 0.005). However, there was no significant difference at 4 months. In conclusion, our study suggests prasugrel was effective in reducing tissue prolapse in the super acute phase in ACS patients compared with clopidogrel. However, the effect of tissue prolapse reduction was not different up to 4 months follow-up.

Clinical feasibility of resting full-cycle ratio as a unique non-hyperemic index of invasive functional lesion assessment.

The resting full-cycle ratio (RFR) is a new physiologic index to assess myocardial ischemia. RFR and fractional flow reserve (FFR), the conventionally used index, have not been directly compared in evaluating the entire cardiac cycle. Accordingly, we aimed to compare the diagnostic performance of RFR directly with FFR and clarify the clinical feasibility of RFR as a unique non-hyperemic index in evaluating the cardiac cycle. The diagnostic performance of RFR was compared with FFR using an automated online calculation software. A total of 156 consecutive patients with 220 intermediate lesions were enrolled. RFR showed significant correlation with FFR (r = 0.774, p < 0.001). RFR systole and RFR diastole did also with FFR (r = 0.918, p < 0.001, and r = 0.733, p < 0.001, respectively). With FFR < 0.80 as a reference standard, RFR showed good diagnostic accuracy (DA: 80.5%), similar DA between RFR systole and RFR diastole (79.6% and 87.5%, p = 0.58, respectively), and good DA in any lesion locations, especially in non-left anterior descending coronary artery (LAD) lesions (73.7% and 87.6% for LAD vs. non-LAD, p < 0.05, respectively). RFR is a feasible and reliable non-hyperemic index regardless of the difference in cardiac cycle in evaluating physiological lesion severity in daily practice.

Epidemiological Features and Clinical Presentations of Acute Coronary Syndrome in Young Patients.

Objective Although acute coronary syndrome (ACS) is an uncommon entity in young patients, it constitutes an important problem due to the devastating effects of the disease on the more active lifestyle of young patients. At present, there are no guidelines regarding the prevention of ACS in young patients. Methods We performed a retrospective study of ACS patients between 2014 and 2017. Epidemiological data, clinical findings, and short-term outcomes were evaluated between young ACS patients (≤50 years old) and elderly ACS patients (>50 years old). Results Of a total of 361 consecutive ACS patients, 37 were young ACS patients (10.2%). Compared with elderly ACS patients, young ACS patients showed a higher prevalence of males (94.6% vs. 73.8%, p<0.001), current smoking (70.3% vs. 29.9%; p<0.001), and overweight persons (67.6% vs. 27.8%, p<0.001). The eicosapentaenoic acid (EPA)/arachidonic acid (AA) ratio was significantly lower in young ACS patients than in elderly ACS patients [0.17 (0.12-0.25) vs. 0.25 (0.18-0.37), p=0.002]. The prevalence of cardio-pulmonary arrest and percutaneous cardiopulmonary support use was higher in young ACS patients than in elderly ACS patients (24.3% vs. 8.6%, p=0.003, 16.2% vs. 3.1%, p<0.001). Conclusion The features were markedly different between young ACS patients and elderly ACS patients. In young ACS patients, smoking, being overweight, and a low EPA/AA ratio were distinctive risk factors, and more serious clinical presentations were observed at the onset of ACS than in older patients.

Diagnostic Performance of High-Resolution Intravascular Ultrasound for the Detection of Plaque Rupture in Patients With Acute Coronary Syndrome.

BACKGROUND: The new 60-MHz high-resolution intravascular ultrasound (HR-IVUS) is the next-generation IVUS technology, providing higher image resolution than conventional IVUS. It gives clear images of plaque morphology and can discriminate the underlying mechanism of acute coronary syndrome (ACS). Our study aimed to evaluate the diagnostic performance of 60-MHz HR-IVUS in the detection of plaque rupture in patients with ACS.Methods and Results:Patients with ACS who underwent percutaneous coronary intervention for de novo native coronary artery lesions were enrolled. Both HR-IVUS and optical coherence tomography (OCT) were performed for the culprit lesions prior to interventions other than aspiration thrombectomy. Keeping plaque rupture detected by OCT as the gold standard, the diagnostic performance of HR-IVUS was evaluated. Overall, 70 patients underwent both HR-IVUS and OCT examinations. Of these, imaging assessments by HR-IVUS were available for all 70 patients (100%), and those by OCT were available for 54 patients (77.1%). Sensitivity, specificity, positive predictive value, negative predictive value, and accuracy of HR-IVUS for identifying a plaque rupture were 84.8%, 57.1%, 75.7%, 70.6%, and 74.1%, respectively. CONCLUSIONS: HR-IVUS had high sensitivity, but modest specificity for identifying OCT-derived plaque rupture. Compared with results from previous conventional IVUS studies, HR-IVUS might have increased ability to detect OCT-derived plaque rupture, but there is still substantial scope for improvement, especially in the specificity.

Spontaneous haemophilus influenzae type B meningoventriculitis with intraventricular debris.

Here we report the first case of spontaneous occurrence of Haemophilus influenzae type B meningoventriculitis. A 47-year-old man suffered from fever and headache. He had neck stiffness, and his cerebrospinal fluid (CSF) was turbid and yellowish. Gram staining and latex agglutination test of his CSF indicated that Haemophilus influenzae type B was the causative organism. Cranial CT and MRI revealed right ventricular debris accumulation, periventricular hyperintense signal, and periventricular ependymal enhancement. He was treated with intravenous administration of antibiotics, and his clinical condition and MRI findings gradually improved. Six weeks after onset, he was discharged without sequelae.