| 1. |
- Abdo, A. A., et al.
(author)
-
Gamma-ray emission concurrent with the nova in the symbiotic binary V407 cygni
- 2010
-
In: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 329:5993, s. 817-821
-
Journal article (peer-reviewed)abstract
- Novae are thermonuclear explosions on a white dwarf surface fueled by mass accreted from a companion star. Current physical models posit that shocked expanding gas from the nova shell can produce x-ray emission, but emission at higher energies has not been widely expected. Here, we report the Fermi Large Area Telescope detection of variable γ-ray emission (0.1 to 10 billion electron volts) from the recently detected optical nova of the symbiotic star V407 Cygni. We propose that the material of the nova shell interacts with the dense ambient medium of the red giant primary and that particles can be accelerated effectively to produce π0 decay γ-rays from proton-proton interactions. Emission involving inverse Compton scattering of the red giant radiation is also considered and is not ruled out.
|
|
| 2. |
|
|
| 3. |
- Sharma, T., et al.
(author)
-
Biomarkers associated with vulnerable plaques
- 2022
-
In: European Heart Journal. - : Oxford University Press. - 0195-668X .- 1522-9645. ; 43:Suppl. 2, s. 1292-1292
-
Journal article (other academic/artistic)abstract
- Background: Cardiovascular heart disease is the leading cause of mortality worldwide, with the rupture or thrombosis of an atherosclerotic plaque being the main reason behind an acute coronary syndrome. It has already been established that the morphology of atherosclerotic plaques determine their stability. A lipid rich lesion with a thin fibrous cap is more prone to rupture compared to solid fibrous lesions. In the PROSPECTII study we used Near infrared spectroscopy (NIRS) and Intravascular ultrasound (IVUS) to identify atherosclerotic plaques in the coronary arteries; NIRS-derived lipid core burden index (LCBI) and IVUS-derived plaque burden (PB) identified plaques that caused adverse cardiovascular events.Purpose: Our aim is to find biomarkers associated with LCBI or PB, to understand the development of vulnerable plaques.Methods: 902 patients were enrolled in this study after successful percutaneous coronary intervention (PCI). A combined NIRS-IVUS catheter was then used to analyze approximately 200m of coronary arteries. Blood samples for biomarker analysis were taken before the PCI procedure and plasma levels of 182 proteins associated with cardiovascular disease were assessed using a novel method for measuring proximity extension assay. Adjusted linear regression models were calculated between the biomarkers and the outcomes of interest, followed by a false discovery rate (FDR) correction.Results: We found 24 proteins associated with plaque burden and 28 proteins associated with LCBI after using a cut off of two tailed P value <0.05. An overlap of 8 biomarkers could be seen between the two groups. After adjusting the P values with FDR, Angiopoeitin like 3 (ANGPTL3) retain edits association to LCBI, and Interleukin 18 receptor 1 (IL18R1) and colony stimulating factor 1 (CSF-1) to plaque burden.Conclusion: We were able to identify different biomarker patterns associated with plaque burden compared to lipid rich vulnerable plaques. ANGPTL3 was shown to only have an association with lipid rich plaques and not with solid fibrous lesions which further supports its role in vulnerable plaques.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
- Ali, Ziad A., et al.
(author)
-
Optical Coherence Tomography Characterization of Coronary Lithoplasty for Treatment of Calcified Lesions : First Description
- 2017
-
In: JACC: Cardiovascular Imaging. - : Elsevier BV. - 1936-878X. ; 10:8, s. 897-906
-
Journal article (peer-reviewed)abstract
- Objectives This study sought to determine the mechanistic effects of a novel balloon-based lithoplasty system on heavily calcified coronary lesions and subsequent stent placement using optical coherence tomography (OCT). Background The Shockwave Coronary Rx Lithoplasty System (Shockwave Medical, Fremont, California) delivers localized, lithotripsy-enhanced disruption of calcium within the target lesion (i.e., lithoplasty) for vessel preparation before stent implantation. Methods We analyzed OCT findings in 31 patients in whom lithoplasty was used to treat severely calcified stenotic coronary lesions. Results After lithoplasty, intraplaque calcium fracture was identified in 43% of lesions, with circumferential multiple fractures noted in >25%. The frequency of calcium fractures per lesion increased in the most severely calcified plaques (highest tertile vs. lowest tertile; p = 0.009), with a trend toward greater incidence of calcium fracture (77.8% vs. 22.2%; p = 0.057). Post-lithoplasty, mean acute area gain was 2.1 mm2, which further increased with stent implantation, achieving a minimal stent area of 5.94 ± 1.98 mm2 and mean stent expansion of 112.0 ± 37.2%. Deep dissections, as part of the angioplasty effect, occurred in 13% of cases and were successfully treated with stent implantation without incidence of acute closure, slow flow/no reflow, or perforation. Conclusions High-resolution imaging by OCT delineated calcium modification with fracture as a major mechanism of action of lithoplasty in vivo and demonstrated efficacy in the achievement of significant acute area gain and favorable stent expansion.
|
|
| 7. |
- Candelaresi, Simon, et al.
(author)
-
SUPERFLARE OCCURRENCE AND ENERGIES ON G-, K-, AND M-TYPE DWARFS
- 2014
-
In: Astrophysical Journal. - 0004-637X .- 1538-4357. ; 792:1, s. 67-
-
Journal article (peer-reviewed)abstract
- Kepler data from G-, K-, and M-type stars are used to study conditions that lead to superflares with energies above 10(34) erg. From the 117,661 stars included, 380 show superflares with a total of 1690 such events. We study whether parameters, like effective temperature or rotation rate, have any effect on the superflare occurrence rate or energy. With increasing effective temperature we observe a decrease in the superflare rate, which is analogous to the previous findings of a decrease in dynamo activity with increasing effective temperature. For slowly rotating stars, we find a quadratic increase of the mean occurrence rate with the rotation rate up to a critical point, after which the rate decreases linearly. Motivated by standard dynamo theory, we study the behavior of the relative starspot coverage, approximated as the relative brightness variation. For faster rotating stars, an increased fraction of stars shows higher spot coverage, which leads to higher superflare rates. A turbulent dynamo is used to study the dependence of the Ohmic dissipation as a proxy of the flare energy on the differential rotation or shear rate. The resulting statistics of the dissipation energy as a function of dynamo number is similar to the observed flare statistics as a function of the inverse Rossby number and shows similarly strong fluctuations. This supports the idea that superflares might well be possible for solar-type G stars.
|
|
| 8. |
- Dweck, MR, et al.
(author)
-
Contemporary rationale for non-invasive imaging of adverse coronary plaque features to identify the vulnerable patient: a Position Paper from the European Society of Cardiology Working Group on Atherosclerosis and Vascular Biology and the European Association of Cardiovascular Imaging
- 2020
-
In: European heart journal. Cardiovascular Imaging. - : Oxford University Press (OUP). - 2047-2412 .- 2047-2404. ; 21:11, s. 1177-1183
-
Journal article (peer-reviewed)abstract
- Atherosclerotic plaques prone to rupture may cause acute myocardial infarction (MI) but can also heal without causing an event. Certain common histopathological features, including inflammation, a thin fibrous cap, positive remodelling, a large necrotic core, microcalcification, and plaque haemorrhage are commonly found in plaques causing an acute event. Recent advances in imaging techniques have made it possible to detect not only luminal stenosis and overall coronary atherosclerosis burden but also to identify such adverse plaque characteristics. However, the predictive value of identifying individual adverse atherosclerotic plaques for future events has remained poor. In this Position Paper, the relationship between vulnerable plaque imaging and MI is addressed, mainly for non-invasive assessments but also for invasive imaging of adverse plaques in patients undergoing invasive coronary angiography. Dynamic changes in atherosclerotic plaque development and composition may indicate that an adverse plaque phenotype should be considered at the patient level rather than for individual plaques. Imaging of adverse plaque burden throughout the coronary vascular tree, in combination with biomarkers and biomechanical parameters, therefore holds promise for identifying subjects at increased risk of MI and for guiding medical and invasive treatment.
|
|
| 9. |
- Erlinge, David, et al.
(author)
-
Identification of vulnerable plaques and patients by intracoronary near-infrared spectroscopy and ultrasound (PROSPECT II) : a prospective natural history study
- 2021
-
In: The Lancet. - : Elsevier. - 0140-6736 .- 1474-547X. ; 397:10278, s. 985-995
-
Journal article (peer-reviewed)abstract
- Background: Near-infrared spectroscopy (NIRS) and intravascular ultrasound are promising imaging modalities to identify non-obstructive plaques likely to cause coronary-related events. We aimed to assess whether combined NIRS and intravascular ultrasound can identify high-risk plaques and patients that are at risk for future major adverse cardiac events (MACEs).Methods: PROSPECT II is an investigator-sponsored, multicentre, prospective natural history study done at 14 university hospitals and two community hospitals in Denmark, Norway, and Sweden. We recruited patients of any age with recent (within past 4 weeks) myocardial infarction. After treatment of all flow-limiting coronary lesions, three-vessel imaging was done with a combined NIRS and intravascular ultrasound catheter. Untreated lesions (also known as non-culprit lesions) were identified by intravascular ultrasound and their lipid content was assessed by NIRS. The primary outcome was the covariate-adjusted rate of MACEs (the composite of cardiac death, myocardial infarction, unstable angina, or progressive angina) arising from untreated non-culprit lesions during follow-up. The relations between plaques with high lipid content, large plaque burden, and small lumen areas and patient-level and lesion-level events were determined. This trial is registered with ClinicalTrials.gov, NCT02171065.Findings: Between June 10, 2014, and Dec 20, 2017, 3629 non-culprit lesions were characterised in 898 patients (153 [17%] women, 745 [83%] men; median age 63 [IQR 55-70] years). Median follow-up was 3.7 (IQR 3.0-4.4) years. Adverse events within 4 years occurred in 112 (13.2%, 95% CI 11.0-15.6) of 898 patients, with 66 (8.0%, 95% CI 6.2-10.0) arising from 78 untreated non-culprit lesions (mean baseline angiographic diameter stenosis 46.9% [SD 15.9]). Highly lipidic lesions (851 [24%] of 3500 lesions, present in 520 [59%] of 884 patients) were an independent predictor of patient-level non-culprit lesion-related MACEs (adjusted odds ratio 2.27, 95% CI 1.25-4.13) and nonculprit lesion-specific MACEs (7.83, 4.12-14.89). Large plaque burden (787 [22%] of 3629 lesions, present in 530 [59%] of 898 patients) was also an independent predictor of non-culprit lesion-related MACEs. Lesions with both large plaque burden by intravascular ultrasound and large lipid-rich cores by NIRS had a 4-year non-culprit lesion-related MACE rate of 7.0% (95% CI 4.0-10.0). Patients in whom one or more such lesions were identified had a 4-year non-culprit lesion-related MACE rate of 13.2% (95% CI 9.4-17.6).Interpretation: Combined NIRS and intravascular ultrasound detects angiographically non-obstructive lesions with a high lipid content and large plaque burden that are at increased risk for future adverse cardiac outcomes.
|
|
| 10. |
- Figtree, Gemma A, et al.
(author)
-
Clinical Outcomes in Patients With ST-Segment Elevation MI and No Standard Modifiable Cardiovascular Risk Factors.
- 2022
-
In: JACC. Cardiovascular interventions. - 1876-7605. ; 15:11, s. 1167-1175
-
Journal article (peer-reviewed)abstract
- The author recently reported ∼50% excess early mortality in patients with first-presentation ST-segment elevation myocardial infarction (STEMI) without standard modifiable cardiovascular risk factors (SMuRFs); the cause of this is not clear.The aim of this study was to examine differences in infarct characteristics and clinical outcomes in patients with versus without SMuRFs (dyslipidemia, hypertension, diabetes mellitus, and smoking).Individual-level data were pooled from 10 randomized percutaneous intervention (PCI) trials in which infarct size was measured within 1 month by either cardiac magnetic resonance or technetium-99m sestamibi single-photon emission computed tomography imaging. First-presentation STEMI was classified into 2 groups according to the presence or absence of at least 1 SMuRF.Among 2,862 patients, 524 (18.3%) were SMuRF-less. After adjusting for study effect, SMuRF-less patients had more frequent poor pre-PCI flow Thrombolysis In Myocardial Infarction 0/1 compared with patients with at least 1 SMuRF (72.0% vs 64.1%; OR: 1.35; 95% CI: 1.08-1.70). There were no independent associations between the presence or absence of SMuRFs at baseline and infarct size (estimate = -0.35; 95% CI: -1.93 to 1.23), left ventricular ejection fraction (estimate = -0.06; 95% CI: -1.33 to 1.20), or mortality at 30 days (HR: 0.46; 95% CI: 0.19-1.07) and 1 year (HR: 0.74; 95% CI: 0.43-1.29).First-presentation STEMI patients with no identifiable baseline SMuRFs had a higher risk of Thrombolysis In Myocardial Infarction flow grade 0/1 pre-PCI. However, after adjustment, there were no significant associations between SMuRF-less status and infarct size, left ventricle ejection fraction, or mortality.
|
|
