Effects of alirocumab on endothelial function and coronary atherosclerosis in myocardial infarction: A PACMAN-AMI randomized clinical trial substudy

BACKGROUND AND AIMS

The effects of protein convertase subtilisin/kexin type 9 (PCSK9) inhibitors on endothelial function as assessed by flow-mediated dilation (FMD) in patients with acute myocardial infarction (AMI) are unknown. Therefore, we aimed to investigate the effects of the PCSK9 inhibitor alirocumab added to high-intensity statin on FMD, and its association with coronary atherosclerosis in non-infarct related arteries using intracoronary intravascular ultrasound (IVUS), near-infrared spectroscopy (NIRS), and optical coherence tomography (OCT).

METHODS

This was a pre-specified substudy among patients recruited at Bern University Hospital, Switzerland, for the randomized-controlled, double-blind, PACMAN-AMI trial, which compared the effects of biweekly alirocumab 150 mg vs. placebo added to rosuvastatin. Brachial artery FMD was measured at 4 and 52 weeks, and intracoronary imaging at baseline and 52 weeks.

RESULTS

139/173 patients completed the substudy. There was no difference in FMD at 52 weeks in the alirocumab (n = 68, 5.44 ± 2.24%) versus placebo (n = 71, 5.45 ± 2.19%) group (difference = -0.21%, 95% CI -0.77 to 0.35, p = 0.47). FMD improved throughout 52 weeks in both groups similarly (p < 0.001). There was a significant association between 4 weeks FMD and baseline plaque burden (IVUS) (n = 139, slope = -1.00, p = 0.006), but not with lipid pool (NIRS) (n = 139, slope = -7.36, p = 0.32), or fibrous cap thickness (OCT) (n = 81, slope = -1.57, p = 0.62).

CONCLUSIONS

Among patients with AMI, the addition of alirocumab did not result in further improvement of FMD as compared to 52 weeks secondary preventative medical therapy including high-intensity statin therapy. FMD was significantly associated with coronary plaque burden at baseline, but not with lipid pool or fibrous cap thickness.

Pretreatment With P2Y12 Inhibitors in ST-Segment Elevation Myocardial Infarction: Insights From the Bern-PCI Registry

BACKGROUND

Evidence to support immediate P2Y12 inhibitor loading in ST-segment elevation myocardial infarction (STEMI) is limited.

OBJECTIVES

This study sought to compare outcomes of STEMI patients receiving immediate or delayed P2Y12 inhibitor treatment.

METHODS

Using data from the prospective Bern-PCI registry between 2016 and 2020, we stratified STEMI patients undergoing percutaneous coronary intervention according to time periods with different institutional recommendations regarding P2Y12 inhibitor pretreatment. In cohort 1 (October 2016-September 2018), immediate P2Y12 inhibitor treatment was recommended. In cohort 2 (October 2018-September 2020), P2Y12 inhibitor treatment was recommended after coronary anatomy was confirmed. The primary endpoint was a composite of major adverse cardiac or cerebrovascular events (MACCEs) defined as all-cause death, recurrent myocardial infarction, stroke, or definite stent thrombosis at 30 days. Sensitivity analysis included only patients in whom these recommendations were followed.

RESULTS

Cohort 1 included 1,116 patients; pretreatment was actually given in 708 (63.4%). Cohort 2 included 847 patients; pretreatment was withheld in 798 (94.2%). The mean age was 65 ± 13 years, and 24% were female. Baseline characteristics were well-balanced between groups. The median difference for P2Y12 loading to angiography was 52 minutes between cohort 1 and 2 and 100 minutes between patients receiving vs not receiving pretreatment. Rates of MACCEs were similar between cohort 1 and cohort 2 (10.1% vs 8.1%; adjusted HR: 0.91; 95% CI: 0.65-1.28; P = 0.59) and between patients receiving vs not receiving pretreatment (7.1% vs 8.4%; adjusted HR: 1.17; 95% CI: 0.78-1.74; P = 0.45).

CONCLUSIONS

In this cohort study of patients with STEMI undergoing primary percutaneous coronary intervention, P2Y12 inhibitor pretreatment was not associated with improved MACCEs.

A pilot study of skin stretching and blood circulation effects of dermal suctioning in dogs

Dermal suctioning has been reported to yield effects similar to those of cupping therapy in humans and horses, including pain reduction, increased blood circulation, improved flexibility, and healing. However, there is a dearth of reported outcomes concerning cupping or dermal suctioning in dogs. In this study, we examined the physiological effects of dermal suctioning in dogs. Employing the Medicell MINI pro8 device, dermal suctioning was applied to the dorsal surfaces of eight healthy beagle dogs for 20 min. Metrics such as body surface temperature, rectal temperature, pulse rate, respiratory rate, and skin pinch test results were gauged. Seven healthy beagle dogs were used as controls, and the same measurements were performed without dermal suctioning. The results showed a significant increase in the body surface temperature and skin pinch test results after dermal suctioning. We believe that the elimination of torsion in the blood vessels and nerves in the shallow fascia positively affected the thermoregulatory mechanism, resulting in an increase in body surface temperature, and also improving skin flexibility. Thus, dermal suctioning promotes subcutaneous blood circulation and improves skin flexibility in dogs. Further research is needed to identify the mechanisms underlying the effects of dermal suctioning and evaluate the stress in dogs caused by the implementation of the process.

Concomitant Coronary Atheroma Regression and Stabilization in Response to Lipid-Lowering Therapy

BACKGROUND

The frequency, characteristics, and outcomes of patients treated with high-intensity lipid-lowering therapy and showing concomitant atheroma volume reduction, lipid content reduction, and increase in fibrous cap thickness (ie, triple regression) are unknown.

OBJECTIVES

This study was designed to investigate rates, determinants, and prognostic implications of triple regression in patients presenting with acute myocardial infarction and treated with high-intensity lipid-lowering therapy.

METHODS

The PACMAN-AMI (Effects of the PCSK9 Antibody Alirocumab on Coronary Atherosclerosis in Patients with Acute Myocardial Infarction) trial used serial intravascular ultrasound, near-infrared spectroscopy, and optical coherence tomography to compare the effects of alirocumab vs placebo in patients receiving high-intensity statin therapy. Triple regression was defined by the combined presence of percentage of atheroma volume reduction, maximum lipid core burden index within 4 mm reduction, and minimal fibrous cap thickness increase. Clinical outcomes at 1-year follow-up were assessed.

RESULTS

Overall, 84 patients (31.7%) showed triple regression (40.8% in the alirocumab group vs 23.0% in the placebo group; P = 0.002). On-treatment low-density lipoprotein cholesterol levels were lower in patients with vs without triple regression (between-group difference: -27.1 mg/dL; 95% CI: -37.7 to -16.6 mg/dL; P < 0.001). Triple regression was independently predicted by alirocumab treatment (OR: 2.83; 95% CI: 1.57-5.16; P = 0.001) and a higher baseline maximum lipid core burden index within 4 mm (OR: 1.03; 95% CI: 1.01-1.06; P = 0.013). The composite clinical endpoint of death, myocardial infarction, and ischemia-driven revascularization occurred less frequently in patients with vs without triple regression (8.3% vs 18.2%; P = 0.04).

CONCLUSIONS

Triple regression occurred in one-third of patients with acute myocardial infarction who were receiving high-intensity lipid-lowering therapy and was associated with alirocumab treatment, higher baseline lipid content, and reduced cardiovascular events. (Vascular Effects of Alirocumab in Acute MI-Patients [PACMAN-AMI]; NCT03067844).

Effect of Alirocumab Added to High-Intensity Statin on Platelet Reactivity and Noncoding RNAs in Patients with AMI: A Substudy of the PACMAN-AMI Trial

OBJECTIVE

 The effect of the PCSK9 (proprotein convertase subtilisin/kexin type 9) inhibitor alirocumab on platelet aggregation among patients with acute myocardial infarction (AMI) remains unknown. We aimed to explore the effect of alirocumab added to high-intensity statin therapy on P2Y12 reaction unit (PRU) among AMI patients receiving dual antiplatelet therapy (DAPT) with a potent P2Y12 inhibitor (ticagrelor or prasugrel). In addition, we assessed circulating platelet-derived noncoding RNAs (microRNAs and YRNAs).

METHODS

 This was a prespecified, powered, pharmacodynamic substudy of the PACMAN trial, a randomized, double-blind trial comparing biweekly alirocumab (150 mg) versus placebo in AMI patients undergoing percutaneous coronary intervention. Patients recruited at Bern University Hospital, receiving DAPT with a potent P2Y12 inhibitor, and adherent to the study drug (alirocumab or placebo) were analyzed for the current study. The primary endpoint was PRU at 4 weeks after study drug initiation as assessed by VerifyNow P2Y12 point-of-care assays.

RESULTS

 Among 139 randomized patients, the majority of patients received ticagrelor DAPT at 4 weeks (57 [86.4%] in the alirocumab group vs. 69 [94.5%] in the placebo group, p = 0.14). There were no significant differences in the primary endpoint PRU at 4 weeks between groups (12.5 [interquartile range, IQR: 27.0] vs. 19.0 [IQR: 30.0], p = 0.26). Consistent results were observed in 126 patients treated with ticagrelor (13.0 [IQR: 20.0] vs. 18.0 [IQR: 27.0], p = 0.28). Similarly, platelet-derived noncoding RNAs did not significantly differ between groups.

CONCLUSION

 Among AMI patients receiving DAPT with a potent P2Y12 inhibitor, alirocumab had no significant effect on platelet reactivity as assessed by PRU and platelet-derived noncoding RNAs.

Effect of High-Intensity Statin Therapy on Atherosclerosis (IBIS-4): Manual Versus Automated Methods of IVUS Analysis

AIMS

Standard manual analysis of IVUS to study the impact of anti-atherosclerotic therapies on the coronary vessel wall is done by a core laboratory (CL), the ground truth (GT). Automatic segmentation of IVUS with a machine learning (ML) algorithm has the potential to replace manual readings with an unbiased and reproducible method. The aim is to determine if results from a CL can be replicated with ML methods.

METHODS

This is a post-hoc, comparative analysis of the IBIS-4 (Integrated Biomarkers and Imaging Study-4) study (NCT00962416). The GT baseline and 13-month follow-up measurements of lumen and vessel area and percent atheroma volume (PAV) after statin induction were repeated by the ML algorithm.

RESULTS

The primary endpoint was change in PAV. PAV as measured by GT was 43.95 % at baseline and 43.02 % at follow-up with a change of -0.90 % (p = 0.007) while the ML algorithm measured 43.69 % and 42.41 % for baseline and follow-up, respectively, with a change of -1.28 % (p < 0.001). Along the most diseased 10 mm segments, GT-PAV was 52.31 % at baseline and 49.42 % at follow-up, with a change of -2.94 % (p < 0.001). The same segments measured by the ML algorithm resulted in PAV of 51.55 % at baseline and 47.81 % at follow-up with a change of -3.74 % (p < 0.001).

CONCLUSIONS

PAV, the most used endpoint in clinical trials, analyzed by the CL is closely replicated by the ML algorithm. ML automatic segmentation of lumen, vessel and plaque effectively reproduces GT and may be used in future clinical trials as the standard.

Impact of alirocumab on plaque regression and haemodynamics of non-culprit arteries in patients with acute myocardial infarction: a prespecified substudy of the PACMAN-AMI trial

BACKGROUND

Treatment with proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors on top of statins leads to plaque regression and stabilisation. The effects of PCSK9 inhibitors on coronary physiology and angiographic diameter stenosis (DS%) are unknown.

AIMS

This study aimed to investigate the effects of the PCSK9 inhibitor alirocumab on coronary haemodynamics as assessed by quantitative flow ratio (QFR) and DS% by three-dimensional quantitative coronary angiography (3D-QCA) in non-infarct-related arteries (non-IRA) among acute myocardial infarction (AMI) patients.

METHODS

This was a prespecified substudy of the randomised controlled PACMAN-AMI trial, comparing alirocumab versus placebo on top of rosuvastatin. QFR and 3D-QCA were assessed at baseline and 1 year in any non-IRA ≥2.0 mm and 3D-QCA DS% >25%. The prespecified primary endpoint was the number of patients with a mean QFR increase at 1 year, and the secondary endpoint was the change in 3D-QCA DS%.

RESULTS

Of 300 enrolled patients, 265 had serial follow-up, of which 193 underwent serial QFR/3D-QCA analysis in 282 non-IRA. At 1 year, QFR increased in 50/94 (53.2%) patients with alirocumab versus 40/99 (40.4%) with placebo (Δ12.8%; odds ratio 1.7, 95% confidence interval [CI]: 0.9 to 3.0; p=0.076). DS% decreased by 1.03±7.28% with alirocumab and increased by 1.70±8.27% with placebo (Δ-2.50%, 95% CI: -4.43 to -0.57; p=0.011).

CONCLUSIONS

Treatment of AMI patients with alirocumab versus placebo for 1 year resulted in a significant regression in angiographic DS%, whereas no overall improvement of coronary haemodynamics was observed.

CLINICALTRIALS

gov: NCT03067844.

Frequency and Distribution of Sheet and Nodular Calcification in Coronary Arteries in Japanese Patients

Whether a nodular calcification (NC), which is the precursor to intracoronary thrombosis, is focally or diffusely distributed in the coronary tree has major implications for ongoing efforts to identify. This study aimed to investigate the frequency and spatial distribution patterns of sheet calcification (SC) and NC in a 3-vessel examination of autopsied human hearts.A total of 323 coronary artery specimens from 110 cadavers were obtained from autopsy cases. After fixation and decalcification, the coronary artery trees were cut every 5 mm into 4-μm transverse cross-sections for histological assessment. An SC was defined as a plate-like calcification of > 1 quadrant of the vessel or > 3 mm in diameter, and NC as nodular calcium deposits separated by fibrin, and a deposit size > 1 mm in diameter.Of the 6,306 histological cross-sections, SCs and NCs were identified in 1,627 (26%) and 233 (4%) cross-sections, respectively. SCs and NCs had a similar distribution pattern in all 3 coronary arteries. In the left anterior descending artery (LAD), NCs were predominantly located in the proximal segment: the first 45 mm from the LAD ostium (72%) and the first 60 mm from the LAD ostium (84%), respectively. However, NCs were evenly distributed throughout the length of the coronary artery in the right coronary artery (RCA) and left circumflex artery (LCX).NCs coexisted with SCs, and tended to cluster in predictable parts within the proximal segments of the LAD, but were evenly distributed throughout the RCA and LCX in coronary arteries from cadavers.

Interrelation between baseline plaque characteristics and changes in coronary atherosclerosis with the PCSK9-inhibitor alirocumab: insights from the PACMAN-AMI randomized trial

Background

Patients with acute myocardial infarction (AMI) frequently experience recurrent atherothrombotic events, largely attributable to non-culprit lesions with high-risk characteristics. Statins can halt the progression of coronary atherosclerosis, and addition of protein convertase subtilisin/kexin type 9-inhibitors (PCSK9i) results in incremental low-density lipoprotein cholesterol (LDL-C) lowering and atheroma regression.

Purpose

We sought to examine the interrelation between baseline imaging characteristics, on-treatment LDL-C levels, and changes in coronary atherosclerosis as assessed by serial, multi-modality intracoronary imaging in patients with AMI.

Methods

This is a post hoc analysis from the PACMAN-AMI randomized trial. Patients were randomly allocated to biweekly alirocumab 150 mg vs. placebo on top of high-intensity statin initiated within 24h of presentation with AMI, and underwent serial imaging of the two non-infarct-related arteries at baseline and after 52 weeks. The primary endpoint was percent atheroma volume (PAV) by intravascular ultrasound (IVUS). Powered secondary endpoints were maximal lipid core burden index (maxLCBI4mm) by near-infrared spectroscopy (NIRS) and minimum fibrous cap thickness (FCTmin) by optical coherence tomography (OCT).

Results

Of 300 randomized patients (mean age 58.5±9.8 years, 18.7% women, baseline LDL-C 3.94±0.87 mmol/L), IVUS was serially performed in 265 patients (537 arteries). LDL-C levels decreased to 1.92±0.79 mmol/L with placebo and 0.61±0.61 mmol/L with alirocumab (p&lt;0.001). Compared with placebo (statin alone), alirocumab added to statin resulted in greater PAV reduction (−2.13% vs. −0.92%; p&lt;0.001), greater maxLCBI4mm reduction (−79.42 vs. −37.60; p=0.006), and greater increase in FCTmin (62.67 vs. 33.19 μm; p=0.001). Changes in PAV and maxLCBI4mm were inversely related to on-treatment LDL-C levels, and change in FCTmin was positively related to on-treatment LDL-C levels (Figure 1). Across all patients, we found significant, inverse relationships between change in PAV and baseline PAV [slope: −0.072 (95% CI −0.101 to −0.042); p&lt;0.001], between change in maxLCBI4mm and baseline maxLCBI4mm [slope: −0.437 (95% CI −0.505 to −0.369); p&lt;0.001], and between change in FCTmin and baseline FCTmin [slope: −0.436 (95% CI −0.541 to −0.332); p&lt;0.001]; these findings indicate greater PAV and maxLCBI4mm regression in lesions with greater PAV and LCBI4mm at baseline, and greater fibrous cap thickening in lesions with thinner fibrous caps at baseline.

Conclusion

In this study of intensive LDL-C lowering treatment initiated in the acute AMI setting, more favorable plaque changes were observed in patients with lower on-treatment LDL-C levels and in lesions with more adverse baseline plaque characteristics. Whether AMI patients with high-risk plaque features might derive greater clinical benefit from early initiation of intensive LDL-C-lowering therapies requires further investigation.

Funding Acknowledgement

Type of funding sources: Private company. Main funding source(s): Sanofi, Regeneron

Impact of alirocumab added to high-intensity statin therapy on platelet function in AMI patients: a pre-specified substudy of the randomized, placebo-controlled PACMAN-AMI trial

Background

Previous small observational studies have suggested a potential association of proprotein convertase subtilisin kexin type 9 (PCSK9) and platelet reactivity. However, the role of the PCSK9 inhibitor alirocumab on platelet aggregation among patients with acute myocardial infarction (AMI) remains unknown.

Purpose

We investigated the effect of alirocumab on P2Y12 reaction unit (PRU) on top of high-intensity statin therapy among AMI patients receiving dual antiplatelet therapy (DAPT) with a potent P2Y12 inhibitor (ticagrelor or prasugrel).

Methods

This was a pre-specified, powered, pharmacodynamic substudy nested within the PACMAN (effects of the PSCK9 antibody AliroCuMab on coronary Atherosclerosis in patieNts with Acute Myocardial Infarction) trial, a randomized, double-blind trial comparing biweekly alirocumab (150mg) versus placebo in AMI patients undergoing percutaneous coronary intervention (PCI). Patients recruited at Bern University Hospital, receiving DAPT with either ticagrelor or prasugrel at 4 weeks and adherent to the study drug (alirocumab or placebo) were analyzed for the current study. The VerifyNow P2Y12 point-of-care assays were used to measure PRU at baseline (i.e. before first study drug administration), 4 weeks, and 52 weeks after study drug administration (higher PRU levels indicating greater platelet aggregation). The primary endpoint was PRU at 4 weeks.

Results

Among 139 randomized patients (mean age 58.2 years [SD, 9.5], 21 [15.0%] women, mean LDL-C level 150.6mg/dL [SD, 30.9]), baseline characteristics were well balanced between groups including baseline PRU (50.0 [IQR, 120.0] in the alirocumab group vs. 62.0 [IQR, 122.0] in the placebo group, P=0.75). At 4 weeks, mean LDL-C was significantly lower in the alirocumab group (23.5 [SD, 23.7] mg/dL vs. 74.4 [SD, 30.5] mg/dL, P&lt;0.001). The majority of patients received ticagrelor DAPT at 4 weeks (57 [86.4%] vs. 69 [94.5%], P=0.14). There were no significant differences in PRU at 4 weeks (12.5 [IQR, 27.0] vs. 19.0 [IQR, 30.0], P=0.26) and at 52 weeks (25.0 [IQR, 37.0] vs. 34.0 [IQR, 59.0], P=0.07) (Figure). Consistent results were observed in 126 patients treated with ticagrelor (i.e. after excluding 13 patients treated with prasugrel) at 4 weeks (13.0 [IQR, 20.0] vs. 18.0 [IQR, 27.0], P=0.28).

Conclusion

Among AMI patients receiving DAPT with potent P2Y12 inhibitors, alirocumab had no significant effect on platelet function as assessed by PRU.

Funding Acknowledgement

Type of funding sources: Public Institution(s). Main funding source(s): Bern University Hospital

Effect of alirocumab added to high-Intensity statin therapy on endothelial function in patients with acute myocardial infarction: a sub-study of the randomized placebo-controlled PACMAN-AMI trial

Background

Endothelial dysfunction is involved early in the development of vascular dysfunction leading to atherosclerosis and cardiovascular diseases. Statins have shown to improve endothelial function. The role of the protein convertase subtilisin/kexin type 9-inhibitor (PCSK9) alirocumab on endothelial function among patients with acute myocardial infarction (AMI) remains unknown.

Purpose

We investigated the effect of alirocumab on endothelial function among AMI patients receiving PCSK9i alirocumab in addition to high intensity statin therapy.

Methods

This is a pre-specified, sub-study nested within the PACMAN-AMI (effects of the PCSK9 antibody AliroCuMab on coronary Atherosclerosis in patieNts with Acute Myocardial Infarction) trial, a randomized trial that compared the effects of biweekly PCSK9-inhibitor alirocumab 150 mg vs. placebo, initiated within 24h of presentation in patients with AMI on top of high-intensity statin. Patients recruited at Bern University Hospital and adherent to the study drug (alirocumab or placebo) were analysed for the current study. Endothelial function was assessed by flow mediated dilation (FMD) of the brachial artery at week 4 and 52 after treatment initiation.

Results

Among 139 patients (68 alirocumab, 71 placebo) completing the sub-study, baseline characteristics were well balanced between groups (alirocumab vs. placebo: mean age 57.5±10.1 years vs. 58.7±8.4 years, p=0.45; mean LDL-C 4.03±0.93 mmol/L vs. 4.05±0.74 mmol/L, p=NS). At week 52 LDL-C levels decreased to 0.65±0.71 mmol/L in the alirocumab group and to 1.98±0.71 mmol/L in the placebo group (p&lt;0.001). There was no difference in FMD at 52 weeks in the alirocumab (5.44±2.24%) versus placebo (5.45±2.19%) group (between groups difference FMD, −0.21% (95% CI −077 to 0.35), p=0.47). Compared to baseline, follow-up FMD was improved in both groups (from 4.52±1.87 to 5.44±2.24%, p&lt;0.001 in the alirocumab group and from 4.32±1.62 to 5.45±2.19%, p&lt;0.001 in the placebo group).

Conclusion

Among patients with acute myocardial infarction, the addition of subcutaneous biweekly alirocumab, compared with placebo, to high-intensity statin therapy did not result in additional improvement of endothelial function after 52 weeks of treatment.

Funding Acknowledgement

Type of funding sources: Public hospital(s). Main funding source(s): The PACMAN-AMI study was supported by a research grant from Sanofi, Regeneron and Infraredx. This substudy was funded by the University of Bern.

Diagnostic Accuracy of Optical Frequency Domain Imaging for Identifying Necrotic Cores with Intraplaque Hemorrhage in Advanced Human Carotid Plaques

This study investigated whether optical frequency domain imaging (OFDI) can identify carotid artery vulnerable plaque characteristics, focusing on lipid-rich necrotic core (NC) and intraplaque hemorrhage (IPH). Fourteen patients scheduled for carotid endarterectomy underwent OFDI scan during preoperative angiography. Atherosclerotic plaque specimens obtained from carotid endarterectomy were cut every 3-4 mm into 4-μm transverse cross-sections and stained with standard methods. Each cross-section was matched with OFDI, and histologically classified into either fibrous, calcific, pathological intimal thickening (PIT), and NC. Of 75 histologic cross-sections, 6 were categorized as fibrous (8%), 18 as calcific (24%), 9 as PIT (12%), and 42 as NC (56%). Tissues categorized as NC had significantly higher OFDI signal attenuation rates than the other tissues (p <0.001), followed by PIT, calcific, and fibrous tissues. The receiver operating characteristic analysis indicated that attenuation rates of >0.023 and >0.031 predicted the presence of NC and IPH with high areas under the curve of 0.91 and 0.88, respectively. OFDI provides potential capability for the detection of NCs with IPH of carotid artery plaques by quantitatively analyzing the attenuation rate.

Tangential signal dropout artefact in optical frequency domain imaging

BACKGROUND

Tangential signal dropout (TSD), which occurs when the optical frequency domain imaging (OFDI) beam strikes the vessel wall under a glancing angle and travels almost parallel to the vessel wall, is the most important imaging artefact leading to the erroneous diagnosis of lipid-rich plaques.

AIMS

This study aimed to evaluate the OFDI artefact of TSD, which mimics the appearance of lipid-rich plaque and macrophage (Mø) infiltration.

METHODS

A total of 1,019 histological cross-sections from 23 autopsy hearts were matched with the corresponding OFDI images. Of these, 232 OFDI cross-sections that contained signal-poor regions with diffuse borders were classified as lipid-rich plaques. The angle θ was calculated between the OFDI beam that strikes the edge of the luminal surface of the low-intensity region and that which strikes the surface line of the low-intensity region.

RESULTS

On histological evaluation, 182 (78%) cross-sections were classified as histologically lipidic/Mø infiltration, while the remaining 50 (22%) cross-sections were classified as histologically non-lipidic/Mø infiltration. The angle θ was significantly smaller in the non-lipidic/Mø infiltration group than in the lipidic/Mø infiltration group (12±6° versus 37±14°, p<0.001). Receiver operating curve analysis revealed that the optimal cut-off value of the incident angle for predicting TSD was 23° with an area under the curve of 0.98.

CONCLUSIONS

When the OFDI imaging beam strikes the tissue at an angle θ<23°, TSD artefact could occur. To eliminate image misinterpretation, our findings suggest that the OFDI catheter geometry should be considered for the accurate diagnosis of lipid-rich plaques and Mø infiltration.

The incidence, natural history, and predictive factors for tissue protrusion after drug-eluting stent implantation

OBJECTIVES AND BACKGROUND

Although tissue protrusion (TP) between the stent struts after stent implantation has been implicate as a potential factor of stent failure, the incidence, natural history, and predictive factor of TP after stent implantation remains unclear. This prospective study evaluated the fate of TP after drug-eluting stent (DES) deployment using optical coherence tomography (OCT).

METHOD AND RESULT

This study analyzed TP for 42 lesions after DES in which three serial OCTs, including preprocedure, postprocedure, and 1-month after the procedure were performed. TP was classified into the five groups: (a) persistent, (b) progressive, (c) healed, (d) regressive, and (e) late-acquired. Immediately after the procedure, 100 TPs in 37 lesions (88%) were identified. Of those, 53 (53%) were persistent, 3 (3%) were progressive, 20 (20%) were healed, and 24 (24%) were regressed at 1-month follow-up. Seven TPs in five patients (13%) were observed only at 1-month follow-up (late-acquired).

CONCLUSION

In lesions with late-acquired TP, calcified nodule was identified as an underlying plaque morphology on preprocedural OCT. A serial OCT analysis found TP occurred not only immediately after DES implantation, but also 1-month after DES implantation.

Automated classification of coronary atherosclerotic plaque in optical frequency domain imaging based on deep learning

BACKGROUND AND AIMS

We developed a deep learning (DL) model for automated atherosclerotic plaque categorization using optical frequency domain imaging (OFDI) and performed quantitative and visual evaluations.

METHODS

A total of 1103 histological cross-sections from 45 autopsy hearts were examined to compare the ex vivo OFDI scans. The images were segmented and annotated considering four histological categories: pathological intimal thickening (PIT), fibrous cap atheroma (FA), fibrocalcific plaque (FC), and healed erosion/rupture (HER). The DL model was developed based on pyramid scene parsing network (PSPNet). Given an input image, a convolutional neural network (ResNet50) was used as an encoder to generate feature maps of the last convolutional layer.

RESULTS

For the quantitative evaluation, the mean F-score and IoU values, which are used to evaluate how close the predicted results are to the ground truth, were used. The validation and test dataset had F-score and IoU values of 0.63, 0.49, and 0.66, 0.52, respectively. For the section-level diagnostic accuracy, the areas under the receiver-operating characteristic curve produced by the DL model for FC, PIT, FA, and HER were 0.91, 0.85, 0.86, and 0.86, respectively, and were comparable to those of an expert observer.

CONCLUSIONS

DL semantic segmentation of coronary plaques in OFDI images was used as a tool to automatically categorize atherosclerotic plaques using histological findings as the gold standard. The proposed method can support interventional cardiologists in understanding histological properties of plaques.

Interobserver variability in assessments of atherosclerotic lesion type via optical frequency domain imaging

BACKGROUND

To date, there have been no data available regarding the diagnostic performance of optical frequency domain imaging (OFDI) for in vivo histological classification of atherosclerotic lesions. This study investigated whether OFDI can be used to diagnose and classify histological atherosclerotic lesions in the coronary artery by ex vivo histological examinations.

METHODS

Three-hundred-fifteen histological cross-sections from 21 autopsy hearts were matched with the OFDI images. Histological cross-sections were classified into six categories: adaptive intimal thickening (AIT), pathological intimal thickening (PIT), fibrous cap atheroma (FA), fibrocalcific plaque (FC), calcified nodule, and healed erosion/rupture. The five observers with different years of experience in the interpretation of OFDI provided a single diagnosis for the OFDI scans of each cross-section according to the aforementioned six histological categories. The diagnostic accuracy and interobserver variability of lesion types for each OFDI observer were determined using histology as the gold standard.

RESULTS

The overall agreement rates between OFDI and histopathologic diagnosis for OFDI observers 1-5 were 81%, 70%, 68%, 61%, and 50% (κ values of 0.75, 0.61, 0.58, 0.49, and 0.36), respectively. Although the diagnostic accuracy of OFDI for detecting AIT and FC was excellent for all five observers, the sensitivity, and positive predictive values of OFDI for detecting PIT and FA were low in proportion to years of experience.

CONCLUSION

The diagnostic accuracy of atherosclerotic tissue properties from OFDI scans correlated with the observers' years of experience, especially when lesions contained lipid components.

The accuracy and interobserver variability in the assessment of coronary atherosclerotic plaques by optical frequency domain imaging: involving five observers with different levels of coronary imaging

Background

Whether optical frequency domain imaging (OFDI) images can realize pathological diagnosis of coronary atherosclerotic plaques, and whether its diagnostic accuracy of lesion types varies depending on the personal experience of the clinician caring for coronary intervention have not been elucidated.

Purpose

This study investigated the interobserver variability in characterizing atherosclerotic plaque types by OFDI for multiple OFDI observers with levels of different experience.

Methods

Three-hundred-thirty-three histological cross-sections from 21 autopsy hearts were co-registered with the corresponding OFDI images. Histological cross-sections were classified into the following 7 lesion types according to the modified AHA atherosclerosis classification by a single experienced pathologist blinded for OCT findings: adaptive intimal thickening (AIT), intimal xanthoma (IX), pathological intimal thickening (PIT), fibrous cap atheroma (FA), fibrocalcific plaque (FC), calcified nodule (CN), and healed erosion/rupture (HER). The five OFDI observers, unaware of the histological diagnosis, provided a single diagnosis for each corresponding OFDI image. The OFDI observer 1 was an expert interventional cardiologist with sufficient experience in OFDI imaging, followed by the OFDI observer 2, 3, and 4 as middle career interventional cardiologists who had completed training ten, seven, and four years. The OFDI observer 5 was a young career interventional cardiologist. The diagnostic accuracy of lesion types for each OFDI observer was determined taking histology as a gold standard.

Results

On histological analysis, 13% of histological cross-sections were diagnosed as AIT, 5% as IX, 23% as PIT, 25% as FA, 27% as FC, 2% as CN, and 5% as HER. The overall agreement between OFDI diagnosis and histopathologic diagnosis for OFDI observer 1 to 5 was 77%, 62%, 61%, 56%, and 46% (k values of 0.71, 0.54, 0.54, 0.45, and 0.33), respectively. Although the performance for characterizing AIT and FC was excellent and comparable among all OFDI observers, the sensitivity and positive predictive value for characterizing IX, PIT and FA varied depending on the OFDI observers' years of experience (Table). The main causes of false-positive or -negative diagnosis of FA were IX and PIT for all OFDI observers.

Conclusion

The diagnostic accuracy of atherosclerotic tissue properties from OFDI images correlated with the observers' years of experience, subspecialty training in coronary imaging, which suggests that the interpretation of OFDI images requires expertise and can be challenging to a less experienced reader.

Table 1

Funding Acknowledgement

Type of funding source: None

Prognostic Value of Psoas Muscle Mass Index in Patients With Non‒ST-Segment‒Elevation Myocardial Infarction: A Prospective Observational Study

Background Muscle wasting is an important predictor of long-term outcome in patients with cardiovascular disease, but the prognostic value of muscle wasting in patients with non‒ST-segment‒elevation myocardial infarction is not established. The aim of this study is to investigate the prognostic value of muscle wasting, defined by psoas muscle mass index (PMI), in patients with non‒ST-segment‒elevation myocardial infarction. Methods and Results A total of 132 consecutive patients with non‒ST-segment‒elevation myocardial infarction were prospectively enrolled between 2015 and 2018. Primary end point was incidence of cardiovascular events including cardiovascular deaths, non-fatal myocardial infarction, or non-fatal stroke. Cross-sectional area of the psoas muscle at the L3 vertebral level was obtained by computed tomography and PMI was calculated. The median follow-up period was 2.4 years (interquartile range, 1.1-4.0 years). There were 45 cardiovascular events (34%) during the study periods. The optimal cutoff value of PMI to predict cardiovascular events was 772 mm2/m2, as assessed by receiver operating curve analysis. Patients with reduced PMI (PMI<772 mm2/m2) had significantly higher cardiovascular events than those with preserved PMI (PMI≥772 mm2/m2) (48% versus 21%; log-rank test P<0.001). Multivariate Cox proportional hazards model revealed that reduced PMI was a statistically significant predictor of cardiovascular events (hazard ratio, 3.30; 95% CI, 1.70-6.40; P<0.001). Conclusions Muscle wasting defined as PMI is a simple and useful objective marker to predict future cardiovascular outcome in patients with non‒ST-segment‒elevation myocardial infarction. Registration Information URL: https://www.umin.ac.jp/ctr/; Unique identifier: UMIN000013445.

Loss of skeletal muscle mass predicts cardiac death in heart failure with a preserved ejection fraction but not heart failure with a reduced ejection fraction

Aims

Loss of skeletal muscle mass is an important determinant associated with poor long‐term prognosis in patients with acute decompensated heart failure (ADHF). However, limited evidence is available. This study investigated the prognostic value of the psoas muscle mass index (PMI) in patients with ADHF.

Methods and results

A total of 210 consecutive patients aged ≥60 years with ADHF were enrolled using a prospective database between 2015 and 2017. Primary endpoint was incidence of cardiac death. Cross‐sectional psoas muscle area at the L3 vertebral level was obtained by computed tomography, and PMI was calculated by height. Reduced PMI was defined as a PMI below the 25th sex‐specific percentile. Patients were also classified by their left ventricular ejection fraction (EF) as having either heart failure with a reduced ejection fraction (HFrEF, EF < 50%) or heart failure with a preserved ejection fraction (HFpEF, EF ≥ 50%). The median follow‐up period was 1.8 years. There were 44 cardiac deaths (21%) during the study period. Patients with reduced PMI had significantly higher cardiac death rates than those with preserved PMI (33% vs. 17%, log‐rank test P = 0.006). In subgroup analysis, HFpEF patients with reduced PMI had significantly higher cardiac death rates than those with preserved PMI (38% vs. 16%, log‐rank test P = 0.006); conversely, HFrEF patients had comparable cardiac death rates regardless of their PMI group (27% for reduced PMI vs. 18% for preserved PMI, log‐rank test P = 0.24). Multivariate Cox proportional hazards model revealed that patients with reduced PMI had a 2.3‐fold higher risk of cardiac death compared with patients with preserved PMI (95% confidence interval 1.23–4.42, P = 0.01).

Conclusions

Reduced PMI helps to predict long‐term outcome in patients with HFpEF but not HFrEF.

Coronary artery calcification as a novel predictive marker of unstable coronary lesion in survivors of out-of-hospital cardiac arrest without ST-segment elevation

AIM

Acute myocardial infarction (AMI) is the leading cause of out-of-hospital cardiac arrest (OHCA). A highly predictive marker is needed to identify AMI in survivors of OHCA without ST-segment elevation because the appropriate indication for emergency coronary artery angiography in patients without ST-segment segment elevation has not been determined. Accordingly, the aim of this study was to elucidate the clinical significance of coronary artery calcification in identifying survivors of OHCA without ST-segment elevation who could benefit from emergency coronary artery angiography.

METHODS

Survivors of OHCA without ST-segment elevation with no obvious extra-cardiac cause who underwent emergency computed tomography and coronary artery angiography were enrolled. Unstable coronary lesion was diagnosed using coronary artery angiography, and presence of coronary artery calcification and coronary artery calcium score were evaluated by non-contrast, non-electrocardiography gated computed tomography.

RESULTS

Thirty of 100 consecutive survivors of OHCA were diagnosed to have unstable coronary lesion. Sensitivity and specificity of coronary artery calcification in identifying unstable coronary lesion were 87% and 60%, respectively. Multivariate logistic regression analysis revealed that coronary artery calcification was an independent predictor of unstable coronary lesion (odds ratio: 7.28, 95% confidence interval: 2.00-26.56, p < 0.001).

CONCLUSION

Evaluation of coronary artery calcification by computed tomography is useful in identifying patients with unstable coronary lesion who could benefit from emergency coronary artery angiography among survivors of OHCA without ST-segment elevation on post-resuscitation electrocardiography.

P5632Different impact of lesion length on fractional flow reserve in intermediate coronary lesions between each coronary artery

Background

Previous studies reported that lesion length was an important geometric parameter in addition to the degree of stenosis in the determinant of functional significance of coronary artery stenosis. Nevertheless, the optimal cutoff value of lesion length for predicting functional significance for each coronary artery has not yet been evaluated, though previous studies revealed that the cutoff value of minimum lumen diameter measured on coronary angiography (CAG) to predict fractional flow reserve (FFR) <0.80 is different for each coronary artery

Purpose

This study evaluated whether the impact of lesion length on functional significance is similar between each coronary artery for lesions with intermediate stenosis.

Methods

Patients with suspected coronary artery disease who had at least one intermediate coronary lesion (luminal diameter stenosis of 70 to 80% by visual estimation on CAG) and underwent FFR measurement for the evaluation of myocardial ischemia were evaluated. Quantitative coronary angiography analysis including percent diameter stenosis and lesion length was performed. FFR was measured as the ratio of the mean distal coronary artery pressure to the mean aortic pressure during maximal hyperemia induced by intravenous infusion of adenosine triphosphate (150 μg /kg/min). The area under the receiver operating characteristics (ROC) curve was estimated for the best cutoff value as a predictor of FFR value of ≤0.80 for each coronary artery.

Results

A total of 221 de novo lesions that underwent FFR measurement were enrolled. The average FFR value was 0.81±0.07. Although lesion length was similar among the lesions with an FFR >0.80 at different locations, the mean lesion length was significantly longer for lesions in the right coronary artery (RCA) with an FFR ≤0.80 than for those in the left anterior descending artery (LAD) and left circumflex artery (13.4±3.4 versus 8.6±3.1 versus 12.0±3.7 mm, p<0.001). ROC analysis demonstrated that the optimal cutoff value of lesion length for predicting an FFR ≤0.80 was 10.0 mm in the LAD (0.56 area under the curve, 48% sensitivity, 76% specificity), whereas 13.1 mm in the RCA (0.84 area under the curve, 67% sensitivity, 93% specificity) (Figure).

ROC analysis of LL for FFR≤0.80

Conclusions

A longer lesion length is required to achieve FFR<0.80 in the RCA than in the other arteries. This may suggest the low possibility of an FFR ≤0.80 when stenosis is focal and short in the RCA with stenosis of 70 to 80% by visual estimation on CAG.

3284Quantification of macrophage presence and identification of thin-cap fibroatheroma by optical coherence tomography image: histopathological validation study

Background

Intracoronary optical coherence tomography (OCT) is thought to be capable of identifying a vulnerable, rupture-prone plaque based on the presence of a thin-cap fibroatheroma (TCFA). Moreover, recent studies have reported that OCT may be able to identify macrophage infiltration of the fibrous cap, a key characteristic of vulnerable plaque.

Purpose

This study evaluated the accuracy of OCT image for characterizing TCFA and identifying macrophage infiltration in comparison with histopathology.

Methods

A total of 924 focal plaques in 206 coronary arteries from 78 autopsy hearts were examined to compare OCT and histological images. By histology, 16 plaques (1.7%) were classified as TCFAsthat contained a large necrotic core covered by a thin (<65μm) fibrous-cap. Correlating OCT-histological sections were identified and OCT-derived tissue property indexes named normalized standard deviation (NSD) and signal attenuation ratio were applied on the fibrous-cap to identify inflamed fibrous-cap defined as a macrophage percentage >10% by histology.

Results

With histology as standard, the sensitivity, specificity, and negative-predictive-value of TCFAs were extremely high (more than 90%). However, the positive-predictive-value of TCFAs was only 32%, which indicated a high proportion of false-positives. Most false-positive diagnoses of OCT for TCFAs contained large amounts of foam cell accumulations on luminal surface without necrotic core. Twelve of 16 fibrous-caps were considered as inflamed and the remaining 4 were non-inflamed on histology. However, no significant difference in NSD and signal attenuation ratio were identified between them. There was moderate correlation of the fibrous-cap thickness between OCT and histology (r2 = 0.41 and p<0.01).

Conclusions

OCT is a promising intracoronary imaging modality for differentiating tissue characteristics (fibrous, calcified, or lipid-rich plaque) and identifying TCFA. However, it is still challenging to precisely identify inflammation, fibrous-cap thickness, and necrotic core in the native coronary artery. Therefore, careful interpretation is required to assess coronary vulnerable plaque by OCT.

Acknowledgement/Funding

None

107Diagnostic accuracy of optical coherence tomography for the identification of in-stent fibroatheroma following stent implantation: an ex-vivo histological validation study

Background

Previous histopathological studies have demonstrated that new atherosclerotic formation within the neointima, called neoatherosclerosis, is one of the most important mechanisms leading to both very late in-stent restenosis and stent thrombosis after stent implantation. Therefore, to distinguish lipid-containing atherosclerotic neointima from other tissues using intracoronary imaging modalities is clinically important to prevent late stent failures.

Purpose

This study evaluated the diagnostic performance of optical coherence tomography (OCT) for the detection of “in-stent fibroatheroma” following stent implantation by comparing cross-sections of the model with the corresponding histological images.

Methods

Fifty stented coronary arteries from the 31 autopsy hearts were imaged by OCT. Coronary arterial histopathological specimens, all of which included more than 30% of %neointimal hyperplasia, were compared with the corresponding OCT cross-sections. Histological in-stent fibroatheroma was defined as neointima containing large necrotic core and inflammatory cells. OCT-derived in-stent fibroatheroma comprised a low-intensity tissue containing a poorly delineated region with invisible stent strut behind low signal intensity.

Results

A total of 122 OCT cross-sections were compared with histological images. OCT examination revealed that 24 images (20%) contained low-intensity tissue inside the neointima. Of those, 5 images, in which stent strut behind low signal intensity was invisible, were diagnosed as OCT-derived in-stent fibroatheroma (4%) (Figure A). By histological analysis, only 4 images were classified as in-stent fibroatheroma (3%) (Figure B). With histology as the gold standard, the sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy for OCT-derived in-stent fibroatheroma were 100%, 99%, 80%, 100%, and 99%, respectively. The only histological finding underlying the false-positive-diagnosis of OCT-derived in-stent fibroatheroma was foam cells accumulation without necrotic core on the neointimal surface (Figure C and D). Most tissue that showed low-intensity tissue with visible stent strut by OCT contained proteoglycan matrix and organized thrombus in the absence of an underlying necrotic core.

Coregistration of OCT with histology

Conclusion

This study showed the potential capability of OCT based on the visualization of stent struts behind low-intensity regions for discriminating in-stent fibroatheroma from other neointimal tissues following stent implantation.

Clinical Implication of Coronary Artery Calcium Score in Survivors of Out-of-Hospital Cardiac Arrest

Background: The aim of this study was to evaluate the clinical ability of coronary artery calcium (CAC) score to identify acute myocardial infarction (AMI) in survivors of out-of-hospital cardiac arrest (OHCA).

Methods and Results: We studied 180 consecutive survivors of OHCA who underwent immediate non-contrast computed tomography (CT) and coronary angiography. Seventy-one patients had ST elevation or left bundle branch block (LBBB; group 1) and 109 patients did not have ST elevation or LBBB (group 2) on post-resuscitation electrocardiogram (ECG). CAC score was significantly higher in AMI compared with non-AMI in groups 1 and 2. The optimal cut-off of CAC score to identify AMI was 11.5 (sensitivity, 80%; specificity, 71%) in group 1, and 27.4 (sensitivity, 80%; specificity, 76%) in group 2. On multivariate analysis, CAC score was the strongest predictive marker of AMI (OR, 10.91; 95% CI: 6.00–25.97). In addition, CAC score was an independent predictor of 30-day survival (OR, 0.38; 95% CI: 0.15–0.95).

Conclusions: Evaluation of CAC is a useful method to identify AMI in survivors of OHCA, regardless of ST changes on post-resuscitation ECG.

Infective Endocarditis Associated with Streptococcal Toxic Shock Syndrome due to Streptococcus dysgalactiae subsp. equisimilis Infection in a Hemodialysis Patient

The risk of infective endocarditis in chronic hemodialysis patients is markedly higher than that in the general population. We report the first case of a hemodialysis patient with infective endocarditis caused by Streptococcus dysgalactiae subsp. equisimilis (SDSE) who presented with streptococcal toxic shock syndrome. In the last decade, there has been an increase in the incidence of SDSE infections. Therefore, it is important to recognize SDSE as a possible causative agent of infective endocarditis in an immunocompromised population, such as hemodialysis patients.

Examination of the appropriate timing of reperfusion therapy for recent myocardial infarction: a Japanese single-center retrospective study

BACKGROUND

The various guidelines clearly mention the treatment strategies for in patient of acute myocardial infarction (MI) presenting more than 24h from symptom onset (recent myocardial infarction, RMI). However, the appropriate timing of reperfusion for RMI is unclear.

METHODS

We retrospectively evaluated 525 consecutive MI patients who underwent percutaneous coronary intervention (PCI) in our hospital between January 2008 and December 2012.

RESULTS

Sixty RMI patients were more frequently associated with cardiac complications such as myocardial rupture (3.3% vs. 0%; p<0.01), ventricular septal rupture (3.3% vs. 0.4%; p<0.05), and congestive heart failure (15% vs. 2.6%; p<0.001) than 272 consecutive ST-elevation myocardial infarction (STEMI) patients. Of the 60 RMI patients, 33 (55.0%) underwent PCI within 7days (early-PCI group) and 27 (45.0%) underwent PCI after 7days (late-PCI group). Left ventricular ejection fraction measured by echocardiography at second hospital day was similar between the groups. The early-PCI group was more significantly associated with cardiogenic shock and heart failure and more frequently required intra-aortic balloon pumping (24.2% vs. 3.7%; p<0.05) than the late-PCI group. There were no significant differences in 30-day mortality, cardiac complications, and major cardiac events during long-term follow-up (12-36 months) between the groups.

CONCLUSION

RMI patients had a higher incidence of cardiac complications than AMI patients. Clinical outcomes were similar between patients undergoing early revascularization and those undergoing late revascularization, although the former group included a higher proportion of patients with severe cardiac failure.

The effectiveness of super-selective injection with anchor balloon technique for collateral channel assessment

The careful assessment of collateral channels is important for a retrograde approach for a chronic total coronary occlusion (CTO). This case report describes a percutaneous coronary intervention for CTO of the distal right coronary artery with good collateral circulation. All visible collateral channels failed by the retrograde approach; however, the procedure was successful using the distal atrial circumflex (AC) channel. Although this distal channel was poorly visualized on standard coronary angiography, it was clearly contrasted retrogradely from the CTO exit using a super-selective injection through the proximal AC channel as the antegrade flow was obstructed by the anchor balloon. This case highlights a unique super-selective injection with anchor balloon technique for collateral channel assessment.

Onset-to-device time of patients who arrive at off-hours: Importance of prehospital management and public awareness for patients with ST-segment elevation myocardial infarction

AIM

The influence of the time of arrival at the hospital on the door-to-device (DTD) time has been investigated; however, the influence on the onset-to-device (OTD) time is unclear in ST-segment elevation myocardial infarction (STEMI) patients. The aim of this study was to investigate the relationship between the time of arrival at the hospital and the OTD time in STEMI patients.

METHODS

We evaluated 377 STEMI patients who underwent primary percutaneous coronary intervention (pPCI) between January 2008 and December 2014.

RESULTS

During the study period, 222 patients arrived at our hospital between 9 AM and 9 PM (on-hours group) and 155 patients arrived between 9 PM and 9 AM (off-hours group). The DTD time was longer in the off-hours group than in the on-hours group (50.4 vs 39.3 minutes; P<.001), while the OTD time was longer in the on-hours group than in the off-hours group (285.7 vs 184.5 minutes, P<.001). The 30-day mortality and peak creatinine kinase levels were similar between the groups. Transfer from a non-pPCI-capable facility to our hospital was more common in the on-hours group than in the off-hours group (49.1% vs 15.5%, P<.001). The OTD time was shorter in patients who directly visited our hospital than in those who were transferred (172.9 vs 338.5 minutes, P<.001).

CONCLUSIONS

The OTD time might be markedly longer in STEMI patients who arrive at the hospital during on-hours than in those who arrive at the hospital during off-hours because of the underuse of emergency medical services at STEMI onset.

The potential hazard of drug-eluting stent-induced coronary vasospasm causing subacute stent thrombosis: a case report

Background

Drug-eluting stent (DES) -induced coronary vasospasm is a well known phenomenon after stent implantation; however, the extent of this risk is still unknown. We report a case in which DES-induced severe coronary vasospasm was clinically suspected as a cause of subacute stent thrombosis (ST).

Case presentation

A 67-year-old man came to our hospital due to chest pain with mild exercise. He was diagnosed with effort angina by coronary angiography and underwent DES implantation in the mid-left ascending artery (LAD) after the administration of dual anti-platelet therapy. The procedure was uneventful, but his symptoms changed from effort angina to rest angina after stenting. Five days after the procedure, subacute ST occurred, requiring aspiration thrombectomy and balloon angioplasty. Thereafter, he continued to report early morning chest discomfort. We performed a spasm provocation test to evaluate the coronary vasomotor response; it revealed severe stent-edge spasm in the left main trunk to the LAD, except for the stented lesion, and total occlusion of the left circumflex artery.

Conclusions

To our knowledge, the present case is the first report describing in-stent thrombosis secondary to stent-edge spasm. This case describes the potential hazard of DES-induced coronary vasospasm. Although there are several overlapping risk factors for ST development, we consider that stent-edge spasm also plays an important role in ST development. Therefore, we should monitor new-onset rest angina after stent implantation and carefully assess DES-induced coronary vasospasm.

Successful treatment of a nonagenarian patient with acute coronary syndrome complicated with chronic total occlusion of the left main coronary artery

Although chronic total occlusion of the left main coronary artery (LMCA) is considered very rare, this condition could be fatal if it becomes complicated with an acute coronary syndrome lesion in the right coronary artery (RCA) which is usually the only remaining coronary artery for the myocardium. We reported a successfully treated case of a nonagenarian patient with ST-segment elevation myocardial infarction, who had subtotal occlusion of the RCA and total occlusion of the LMCA with Rentrop grade 2 collateral coronary artery supply from the RCA.

Acute myocardial infarction with "wrap around" right coronary artery mimicking Takotsubo cardiomyopathy: a case report

Background

Takotsubo cardiomyopathy (TC) is a cardiomyopathy that shows distinctive clinical conditions first described more than 20 years ago. Because clinical features of TC mimic those of anterior acute myocardial infarction (AMI), the differential diagnosis is important in selecting the appropriate treatment strategy in the acute phase. But it was difficult to differentiate those two diseases because the TC-like findings; such as the electrocardiogram (ECG) changes and left ventricular wall motion abnormality can occur in AMI especially with the anatomical variance of the coronary artery.

Case presentation

A 63-year-old man was admitted due to sudden onset of chest pain and was in a cardiogenic shock state. His ECG showed ST-segment elevation in precordial (V2–6) and inferior leads (II, III, and aVF) and ST-segment depression in lead aVR. Blood biochemistry showed that cardiac enzymes were not elevated. Ultrasonic cardiography showed that the left ventricular apical level was akinetic, papillary muscle level was severely hypokinetic, and basal level was hyperkinetic, mimicking TC. However, coronary angiogram showed total occlusion of his right coronary artery wrapping around the cardiac apex. Successful percutaneous coronary intervention reversed his critical status.

Conclusion

To our knowledge, the present case is the first report described AMI with wrap-around RCA, mimicking TC. Although TC is increasingly recognized as a true but relatively infrequent clinical entity, it is still important to carefully rule out obstructive coronary artery disease.

Context dependent discharge characteristics of saccade-related Purkinje cells in the cerebellar hemispheres of the monkey

In the previous paper (Mano et al, 1991), we reported the discharge patterns of saccade-related Purkinje cells during visually guided saccade task, which were recorded from posterior cerebellar hemisphere, the Crus IIa. In the present study, we analysed these P-cell's simple spike activity during the spontaneous saccade in inter-trial intervals (ITI) of visually guided saccade task, comparing with the activity during the visually guided saccade. We found that the modulation of simple spike discharges during spontaneous saccade was weaker than the modulation during the visually triggered saccade. We recorded single unit discharges of Purkinje cells from cerebellar posterior hemisphere (Crus IIa) in awake Japanese monkeys (Macaca fuscata), trained to perform simple reaction time saccade task gazing at a small light rear-projected on to a tangent screen 54 cm in front of the monkey. Horizontal and vertical eye positions were measured by a corneal search coil method. Comparison of simple spike activity associated with spontaneous saccade during ITI to the activity during visually triggered saccade clarified that the discharge patterns of simple spikes are basically the same during both types of the saccades, but the amount of the phasic modulation (increase of decrease of discharge rate) were larger for all directions (up, down, left and right) during visually guided saccade than that during spontaneous saccade in all saccade-related Purkinje cells so far examined in two monkeys. The modulation, however, cannot be assumed to have been induced by the visual stimulus per se. Because, the maximum increase of simple spike discharge rate aligned at saccade onset is larger than that aligned at target jump. And, the half width of the change was wider when aligned at target light jump than when aligned at the onset of saccades, in all the four directions, indicating the changes of the firing rate were more time-locked to the onset of saccadic eye movements than to the triggering visual stimulus. The present findings suggest that the cerebellar hemisphere plays a more important role in the control of externally triggered voluntary eye movements than in the control of self-initiated, self-paced eye movements. We discussed these findings combining with previous findings on limb movement-related P-cells (Mano et al, 1980, 1986, 1989), from view point of the general role of the cerebellar hemisphere in the control of voluntary movements.

Functional properties of rotation-sensitive neurons in the posterior parietal association cortex of the monkey

We studied the functional properties of rotation-sensitive (RS) neurons of the posterior parietal association cortex in detail. We classified 58 neurons as RS neurons on the basis of statistical analysis, to indicate that their responses to rotary movement were significantly greater (P < 0.01) than those to linear movement of the same stimulus. We calculated rotation index, 1-(L/R), in 82 cells, where L/R is the ratio of net response to linear movement to that to rotary movement. All the RS neurons had rotation index greater than or equal to 0.3. The recording site of these RS neurons was localized in the posterolateral part of area PG (area 7a of Vogt), on the anterior bank of the caudal superior temporal sulcus (STS), in the region partly overlapping the medial superior temporal (MST) area. We compared the response of RS neurons to rotation with that to shearing movement as well as to linear movement. In the majority of RS neurons the ratio of shearing response to rotation response (S/R) was smaller than the ratio of linear response to rotation response (L/R), indicating that the response to rotation was not due to a simple combination of linear movements in the opposite direction. Most of the RS neurons responded to the rotary movement of a single spot as well as that of a slit, although the response was smaller (average 70%) for the former. Most of the RS neurons had large receptive fields (60-180 degrees in diameter) and their responses were independent of the position within the receptive field. The responses of most RS neurons increased monotonically with the increase in angular velocity and were also dependent on the size of the stimulus, although the rate of increase was small when the length was more than 10 degrees. The majority of RS neurons (37/58) responded better to rotation in depth than to that in the frontoparallel plane. Some of them (12/37) responded to diagonal rotation rather than to sagittal or horizontal rotation. We found that some depth RS neurons showed reversal in the preferred direction when we used a trapezoidal window-like plate as the rotating stimulus in the monocular viewing condition, just as occurs in the case of the Ames window illusion. The response of some RS neurons (5/7) was enhanced by tracking eye movement.(ABSTRACT TRUNCATED AT 400 WORDS)

Saccade-related Purkinje cells in the cerebellar hemispheres of the monkey

Extracellular single unit discharges of cerebellar Purkinje cells (P-cells) were recorded from the cerebellar hemispheres of two Japanese monkeys (Macaca fuscata) during spontaneous and visually guided eye movements. We found that saccade-related P-cells, whose simple-spike (SS) discharge rates were modulated in close correlation with saccadic eye movements, were localized in fairly restricted areas in the hemisphere, mostly in Crus IIa with some in the deep folia of Crus I. P-cells located in simple lobules, superficial folia of Crus I or in Crus IIp did not change their discharge rate during voluntary eye movements. Fifty-five saccade-related P-cells recorded from Crus I and II showed modulation of SS discharge rate related to both spontaneous and visually triggered saccades, with the modulation closely time-locked to the saccades. Two thirds (37/55) of saccade-related P-cells began to change their SS discharge rate 20-100 ms prior to the onset of saccades. The remaining one third (18/55) changed their activity approximately at the same time as the saccade onset. These saccade-related P-cells did not show changes in activity during smooth pursuit eye movements, and we did not find any P-cells in the cerebellar hemisphere which showed changes of activity preferentially during smooth pursuit eye movements. In about half (26/55) of the saccade-related P-cells, the pattern of modulation prior to and during saccades was biphasic: increase-decrease or decrease-increase. The other half (29/55) showed monophasic increases or decreases. For a given P-cell, the discharge pattern during saccades was similar for saccades of all directions, though there was a preferred direction in the amount of discharge rate modulation. The present findings suggest that the cerebellar hemisphere (Crus I and IIa) plays an important role in the control of voluntary saccadic eye movements, in addition to other cerebellar cortical areas (flocculus and posterior vermis) which are known to participate in the control of saccades.

Parietal cortical neurons responding to rotary movement of visual stimulus in space

We found in the posterior parietal association cortex (area 7a) of alert monkeys a group of neurons that were specifically sensitive to the rotation of a visual stimulus (N = 21). They responded to rotation of a stimulus in a particular direction much better than to the linear movement in any direction, regardless of shape or orientation of the stimulus. Responses were relatively independent of stimulus position within relatively large receptive fields. The majority of these neurons (N = 13) responded to rotation in depth either in the saggital, horizontal or diagonal plane rather than in the frontoparallel plane. These neurons were localized in a small region on the anterior bank of the superior temporal sulcus and may be related directly to the perception of rotation of visual objects in space.

Neural mechanisms of space vision in the parietal association cortex of the monkey

Functional properties of visual and eye-movement-related neurons of area 7a were studied in alert behaving monkeys. Visual fixation (VF) neurons had selectivity in the direction and/or distance of gaze, signaling the spatial position. Visual tracking (VT) neurons had selectivity in the direction of movement, signaling the movement in space. Many passive visual (PV) neurons were suppressed during eye movement, discriminating real from "self-induced" movement. A group of PV neurons sensitive to the depth movement responded to the changing image size. A group of neurons sensitive to the rotation of visual stimulus in space were also found in area 7a.

Saccade and blinking evoked by microstimulation of the posterior parietal association cortex of the monkey

Electrical stimulation with microelectrodes of the posterior parietal association cortex in alert behaving monkeys elicited saccadic eye movements and blinking. The sites in which saccades were elicited by electrical stimulation were concentrated in the anteromedial part of area 7a, especially in the posterior bank of the intraparietal sulcus, in a region which sends efferent projections to the frontal eye field and the superior colliculus, but they were also found in the posterolateral part of area 7a. Compared with the frontal eye fields and the superior colliculus, the threshold current for eliciting saccades was relatively high, on the average 86 microA. Moreover, the elicitation of saccade was inconsistent even with suprathreshold stimulation and suppressed during visual fixation. Latencies of the saccades were relatively long, on the average 50ms; they were longer in the posterolateral part than in the anteromedial part. Direction and amplitude of evoked saccades depended on the site of stimulation, but was independent of eye position in most cases. However, "goal-directed" saccades which depended on initial eye position were elicited in three penetrations in the posterolateral part of area 7a. The threshold of mainly in the lateral part of area 7a. The threshold of blinking was 70 microA and the latency was 50 ms on the average. In contrast to saccades, blinking was elicited constantly with each stimulus even during attentive fixation. We occasionally recorded single unit activity at the site of stimulation with the same electrodes. More than half of the units recorded at the site of blinking responded to approaching visual stimulus.(ABSTRACT TRUNCATED AT 250 WORDS)

Spatial properties of visual fixation neurons in posterior parietal association cortex of the monkey

1. A systematic study of the positional selectivity of visual fixation (VF) neurons of the posterior parietal association cortex (area 7a or PG) was made in seven hemispheres of four alert behaving monkeys. By gaze fixation on a small spot of light in space, 125 units were identified as VF neurons. the position of the fixation target was varied not only in the frontal plane, but also in depth. 2. Microelectrode penetrations were made in the anterior and posterior part of area 7a. The recording sites of 104 VF neurons, determined histologically, were distributed mainly in the posterior part: the caudal part of the posterior bank of the intraparietal sulcus and the caudal third of the anterior bank of the superior temporal sulcus. The following conclusions are based mainly on the observations of the VF neurons in the posterior part of area 7a. 3. Most of the VF neurons examined in the frontal plane (86/93) had a preferred direction of gaze along the horizontal (39/86), vertical (38/86), or diagonal axis (9/86), and their discharge rates were monotonic increasing functions of the angle of deviation from the center. 4. Many VF neurons had selectivity in the depth of fixation. The majority (41/63) were activated more intensely when the fixation point was nearer to the animal (less than 50 cm), whereas a considerable number (18/63) were activated better when the fixation point was further from the animal (100 cm or more). There were a few units (4/63) that discharged maximally at intermediate distances. 5. Thirty-two VF neurons were studied in detail along all three axes: vertical, horizontal, and depth. About half of them (17/32) were found to be selective both in the radial direction and the distance of fixation, while the others displayed selectivity in the direction of gaze alone (11/32) or in depth alone (4/32). 6. The activity of VF neurosis in the dark was compared to that in a lighted room in order to examine their relationship to eye position in detail. Half of the VF neurons tested (25/50) showed almost the same discharge rate in the dark as in the lighted room in spite of the absence of visual stimuli other than the target light in the fovea. Moreover, the discharge rate of the majority of these VF neurons displayed a close correlation with eye position, even in complete darkness. On the other hand nearly half of the VF neurons (22/50) showed a decrease in discharge rate in the dark during fixation at preferred positions suggesting that visual stimuli in the surroundings have some excitatory effects on these neurons. There were also some VF neurons whose activity decreased when the target light was interrputed. Even in such visually sensitive VF neurons, their positional selectivity depended mainly on eye position. 7...