Room-temperature quantum emission from interface excitons in mixed-dimensional heterostructures

The development of van der Waals heterostructures has introduced unconventional phenomena that emerge at atomically precise interfaces. For example, interlayer excitons in two-dimensional transition metal dichalcogenides show intriguing optical properties at low temperatures. Here we report on room-temperature observation of interface excitons in mixed-dimensional heterostructures consisting of two-dimensional tungsten diselenide and one-dimensional carbon nanotubes. Bright emission peaks originating from the interface are identified, spanning a broad energy range within the telecommunication wavelengths. The effect of band alignment is investigated by systematically varying the nanotube bandgap, and we assign the new peaks to interface excitons as they only appear in type-II heterostructures. Room-temperature localization of low-energy interface excitons is indicated by extended lifetimes as well as small excitation saturation powers, and photon correlation measurements confirm antibunching. With mixed-dimensional van der Waals heterostructures where band alignment can be engineered, new opportunities for quantum photonics are envisioned.

Impact of diabetes mellitus and triglyceride glucose index on mortality and cardiovascular outcomes in patients with chronic coronary syndrome undergoing coronary computed tomography angiography

Background

There is limited knowledge regarding whether an elevated triglyceride glucose (TyG) index can serve as a prognostic marker for mortality and cardiovascular outcomes, independent of diabetes mellitus (DM) and plaque burden, in patients with chronic coronary syndrome (CCS).

Methods

Patients with CCS (n = 684) were categorized into subgroups based on the presence of DM, and patients without DM were further divided into two groups based on presence or absence of an elevation of TyG index >8.8. Coronary plaque burden was evaluated using coronary computed tomography angiography. Major cardiovascular adverse event (MACE) was defined as a composite event of nonfatal myocardial infarction, unstable angina or unplanned coronary revascularization, stroke, non-cardiovascular mortality and cardiovascular mortality.

Results

Patients without DM exhibited significantly greater plaque and epicardial adipose tissue volumes than those with DM. Multivariable Cox proportional hazards models demonstrated that DM and an elevated TyG index >8.8 were independently associated with the risk of MACE after adjusting for age, sex, and plaque volume. Patients with DM (hazard ratio, 3.74; 95% confidence interval, 1.97-7.08; p < 0.001) and patients without DM with an elevated TyG index (hazard ratio, 1.99; 95% confidence interval, 1.01-3.91; p = 0.045) had an increased risk of MACE.

Conclusion

This study indicates that DM and an elevated TyG index are predictors of MACE, independent of plaque volume, in patients with CCS.

Utility and optimal dose of nicorandil for physiological assessment of the femoropopliteal artery

BACKGROUND

Nicorandil is widely used as a vasodilator for the physiological assessment of coronary arteries because of its usefulness and safety; however, there are no data on its use in peripheral arteries.

AIMS

To identify the utility of nicorandil and its appropriate dose for the physiological assessment on the femoropopliteal artery.

METHODS

We retrospectively enrolled patients from three institutes in which physiological assessment was carried out with various doses of nicorandil before treatment. Twenty-four femoropopliteal artery stenotic lesions from 22 patients were included. The nicorandil doses used were 2, 4, and 6 mg. Twenty-two lesions were also assessed using 30 mg of papaverine. The pressure gradient (PG) and peripheral fractional flow reserve (pFFR) were calculated based on the mean and systolic pressure levels. We examined the correlation of each parameter with the peak systolic velocity ratio (PSVR) based on the duplex ultrasound images using Spearman's rank correlation coefficient. Systemic blood pressure was assessed for safety.

RESULTS

The correlations were higher for mean pressure-based parameters than for systolic pressure-based parameters. As the nicorandil dose increased, the correlations among PG, pFFR, and PSVR also increased (mean pressure-based PG: 2 mg, r = 0.360; 4 mg, r = 0.498; 6 mg, r = 0.694, mean pressure-based pFFR: 2 mg, r = -0.479; 4 mg, r = -0.469; 6 mg, r = -0.641). The blood pressure after the administration of 6 mg of nicorandil was low, and the median systemic mean pressure was 65 mmHg.

CONCLUSION

A 4 mg dose of nicorandil is effective and safe for the mean pressure-based physiological assessment of lesions in the femoropopliteal artery.

Segmentation of anatomical layers and imaging artifacts in intravascular polarization sensitive optical coherence tomography using attending physician and boundary cardinality losses

Intravascular ultrasound and optical coherence tomography are widely available for assessing coronary stenoses and provide critical information to optimize percutaneous coronary intervention. Intravascular polarization-sensitive optical coherence tomography (PS-OCT) measures the polarization state of the light scattered by the vessel wall in addition to conventional cross-sectional images of subsurface microstructure. This affords reconstruction of tissue polarization properties and reveals improved contrast between the layers of the vessel wall along with insight into collagen and smooth muscle content. Here, we propose a convolutional neural network model, optimized using two new loss terms (Boundary Cardinality and Attending Physician), that takes advantage of the additional polarization contrast and classifies the lumen, intima, and media layers in addition to guidewire and plaque shadows. Our model segments the media boundaries through fibrotic plaques and continues to estimate the outer media boundary behind shadows of lipid-rich plaques. We demonstrate that our multi-class classification model outperforms existing methods that exclusively use conventional OCT data, predominantly segment the lumen, and consider subsurface layers at most in regions of minimal disease. Segmentation of all anatomical layers throughout diseased vessels may facilitate stent sizing and will enable automated characterization of plaque polarization properties for investigation of the natural history and significance of coronary atheromas.

Thoracic Aortic Plaque Burden and Prediction of Cardiovascular Events in Patients Undergoing 320-row Multidetector CT Coronary Angiography

AIM

Wide volume scan (WVS) coronary computed tomography angiography (CCTA) enables aortic arch visualization. This study assessed whether the thoracic aortic plaque burden (TAPB) score can predict major cardiovascular adverse events (MACE) in addition to and independently of other obstructive coronary artery disease (CAD) attributes.

METHODS

This study included patients with suspected CAD who underwent CCTA (n=455). CCTA-WVS was used to assess CAD and the prognostic capacity of TAPB scores. Data analysis included the coronary artery calcification score (CACS), CAD status and extent, and TAPB score, calculated as the sum of plaque thickness and plaque angle at five thoracic aortic segments. The primary endpoint was MACE defined as a composite event comprised of ischemic stroke, acute coronary syndrome, and cardiovascular death.

RESULTS

During a mean follow-up period of 2.8±0.9 years, 40 of 455 (8.8%) patients experienced MACE. In the Cox proportional hazards model adjusted for clinical risks (Suita cardiovascular disease risk score), we identified TAPB score (T3) as a predictor of MACE independent of CACS ＞400 (hazards ratio [HR], 2.91; 95% confidence interval [CI], 1.26-6.72; p=0.012) or obstructive CAD (HR, 2.83; 95% CI, 1.30-6.18; p=0.009). The area under the curve for predicting MACE improved from 0.75 to 0.795 (p value=0.008) when TAPB score was added to CACS ＞400 and obstructive CAD.

CONCLUSIONS

We found that comprehensive non-invasive evaluation of TAPB and CAD has prognostic value in MACE risk stratification for suspected CAD patients undergoing CCTA.

Tissue responses to everolimus-eluting stents implanted in severely calcified lesions following atherectomy

Histopathological examination has revealed that stents on severely calcified plaques were associated with delayed vascular healing. Although atherectomy devices can increase the number of malapposed struts, tissue responses to implanted drug eluting stents in atherectomy patients remain largely unknown. This retrospective observational study included 30 patients who underwent atherectomy and everolimus-eluting stent (EES) deployment for severely calcified coronary lesions (biodegradable polymer EES (BP-EES), n = 15; durable polymer EES (DP-EES), n  = 15). Optical coherence tomography was carried out at baseline and follow-up, and struts with acute stent malapposition (ASM) were categorized as struts on modified calcium (mod-Ca), non-modified calcium (non-mod-Ca), or non-calcium (non-Ca). Adequate vascular healing, defined as ASM resolution with neointimal coverage, was compared between the BP-EES and DP-EES groups. Multivariate linear regression analysis using a generalized estimated equation revealed that BP-EES use was associated with significantly better adequate vascular healing compared with DP-EES (odds ratio [OR]: 3.691, 95% confidence interval [CI] 1.175-11.592, P = 0.025). adequate vascular healing was associated with the underlying plaque morphology (mod-Ca vs non-mod-Ca: OR 2.833, 95% CI 1.491-5.384, P = 0.001; non-Ca vs non-mod-Ca: OR 1.248, 95% CI 0.440-3.543, P = 0.677). This study demonstrates that drug-eluting stent selection and calcium modification are possible factors affecting vascular healing of malapposed struts in severely calcified lesions.

Innate Immune System Regulated by Stimulator of Interferon Genes, a Cytosolic DNA Sensor, Regulates Endothelial Function

Background Sterile inflammation caused by metabolic disorders impairs endothelial function; however, the underlying mechanism by which hyperglycemia induces inflammation remains obscure. Recent studies have suggested that stimulator of interferon genes (STING), a key cytosolic DNA sensor in the innate immune system, contributes to the pathogenesis of inflammatory diseases. This study examines the role of the STING in endothelial dysfunction in streptozotocin-induced diabetic mice. Methods and Results Injection of streptozotocin promoted the expression of STING and DNA damage markers in the aorta of wild-type mice. Streptozotocin elevated blood glucose and lipid levels in both wild-type and STING-deficient mice, which showed no statistical differences. Genetic deletion of STING ameliorated endothelial dysfunction as determined by the vascular relaxation in response to acetylcholine (P<0.001) and increased endothelial nitric oxide synthase phosphorylation in the aorta (P<0.05) in STZ-injected mice. Endothelium-independent vascular response to sodium nitroprusside did not differ. Treatment with a direct STING agonist, cyclic GMP-AMP, or mitochondrial DNA increased inflammatory molecule expression (eg, VCAM1 and IFNB) and decreased endothelial nitric oxide synthase phosphorylation in human umbilical vein endothelial cells, partially through the STING pathway. Cyclic GMP-AMP significantly impaired endothelial function of aortic segments obtained from wild-type mice, which was ameliorated in the presence of C-176, a STING inhibitor, or a neutralizing interferon-β antibody. Furthermore, the administration of C-176 ameliorated endothelial dysfunction in STZ-induced diabetic mice (P<0.01). Conclusions The DNA damage response regulated by STING impairs endothelial function. STING signaling may be a potential therapeutic target of endothelial dysfunction caused by hyperglycemia.

Role of plaque imaging for identification of vulnerable patients beyond the stage of myocardial ischemia

Chronic coronary syndrome (CCS) is a progressive disease, which often first manifests as acute coronary syndrome (ACS). Imaging modalities are clinically useful in making decisions about the management of patients with CCS. Accumulating evidence has demonstrated that myocardial ischemia is a surrogate marker for CCS management; however, its ability to predict cardiovascular death or nonfatal myocardial infarction is limited. Herein, we present a review that highlights the latest knowledge available on coronary syndromes and discuss the role and limitations of imaging modalities in the diagnosis and management of patients with coronary artery disease. This review covers the essential aspects of the role of imaging in assessing myocardial ischemia and coronary plaque burden and composition. Furthermore, recent clinical trials on lipid-lowering and anti-inflammatory therapies have been discussed. Additionally, it provides a comprehensive overview of intracoronary and noninvasive cardiovascular imaging modalities and an understanding of ACS and CCS, with a focus on histopathology and pathophysiology.

Evaluations of coronary microvascular dysfunction in a patient with thrombotic microangiopathy and cardiac troponin elevation: a case report

Background

Thrombotic microangiopathy (TMA) syndromes include thrombotic thrombocytopenic purpura (TTP) and haemolytic uremic syndrome, and contribute to myocardial infarction and multiple organ failure. Although coronary microvascular dysfunction (CMD) is the key for understanding the pathophysiology of cardiac involvement in TMA, there is limited knowledge on the recovery from CMD in patients with TMA.

Case summary

An 80-year-old woman was brought to the emergency department due to worsening back pain, dyspnoea on exertion, jaundice, and fever. Although she had typical TTP symptoms and elevated cardiac troponin level, ADAMTS13 activity was preserved (34%), leading to the diagnosis of TMA with myocardial infarction. She underwent plasma exchange and was administered aspirin and prednisolone. Magnetic resonance imaging revealed iliopsoas abscess, which is a possible aetiologic factor of sepsis-related TTP. She had impaired coronary flow reserve (CFR) with angiographically non-obstructive epicardial coronary arteries. Improved CFR was observed on follow-up, suggesting existence of transient CMD caused by TMA. After treatment of the iliopsoas abscess with antibiotics for 3 months, she was discharged without any adverse complications.

Discussion

Coronary microvascular dysfunction is an underlying mechanism of myocardial infarction, with or without epicardial obstructive coronary artery stenosis. TMA is characterized by pathological lesions caused by endothelial cell damage in small terminal arteries and capillaries, with complete or partial occlusion caused by platelet and hyaline thrombi. CMD and its recovery are keys for understanding the natural history of cardiac involvement in TMA. In vivo evaluations of CMD can provide mechanistic insights into the cardiac involvement in TMA.

Risk factors for rectal bleeding after volumetric-modulated arc radiotherapy of prostate cancer

Background

It is crucially important to understand the risk factors for rectal bleeding after volumetric-modulated arc radiotherapy (VMAT) for prostate cancer to prevent subsequent rectal bleeding. We assayed clinical and dosimetric data to investigate the risk factors for rectal bleeding after VMAT of prostate cancer.

Materials and methods

This study included 149 patients with prostate cancer who received VMAT from February, 2012 to June, 2020. Irradiated total doses were 78 Gy/39 fractions in 33 patients (22.1%), 76 Gy/38 fractions in 89 (59.7%), 74 Gy/37 fractions in 4 (2.7%), and 72 Gy/36 fractions in 23 (15.4%). We investigated multiple clinical and dosimetric factors with reference to rectal bleeding.

Results

The median observation period was 38 months. Fourteen patients (9.4%) experienced rectal bleeding: five (3.4%) were classified as Grade 2, and nine (6.0%) as Grade 1. There were significant differences between Grade ≥ 1 and Grade 0 patients in the overlap region of the planning target volume (PTV) and the rectum, the rectal V30-75, and the mean rectal dose (p < 0.05). There were significant differences between Grade 2 and Grade 0-1 patients in rectal V30-65 and mean rectal dose (p < 0.05).

Conclusions

Rectal bleeding occurred, but its grades and rate of occurrence were permissible. Higher rectal doses were shown to be related to rectal bleeding, and reduction of low/intermediate and mean rectal doses will be important for preventing rectal bleeding.

Aortic arch plaque morphology in patients with coronary artery disease undergoing coronary computed tomography angiography with wide-volume scan

BACKGROUND

Wide-volume scanning with 320-row multidetector computed tomography coronary angiography (CTCA-WVS) enables the assessment of the aortic arch plaque (AAP) morphology and coronary arteries without requiring additional contrast volume. This study aimed to investigate the prevalence of AAPs and their association with coronary artery disease (CAD) and major adverse cardiovascular events (MACEs) in patients who underwent CTCA-WVS.

METHODS

This study included 204 patients without known CAD (mean age, 65 years; 53% men) who underwent CTCA-WVS. We evaluated the presence of aortic plaques in the ascending aorta, aortic arch, and thoracic descending aorta using CTCA-WVS. Large aortic plaques were defined as plaques of at least 4 mm in thickness. A complex aortic plaque was defined as a plaque with ulceration or protrusion. MACEs were defined as composite events of cardiovascular (CV) death, nonfatal myocardial infarction, and ischemic stroke.

RESULTS

AAPs and large/complex AAPs were identified in 51% ( n = 105) and 18% ( n = 36) of the study patients, respectively. The prevalence of AAPs with large/complex morphology increased with CAD severity (2.1% in no CAD, 12% in nonobstructive CAD, and 39% in obstructive CAD). The univariate Cox hazard model demonstrated that the predictors associated with MACEs were diabetes, obstructive CAD, and large/complex AAPs. Independent factors associated with large/complex AAPs were male sex [odds ratio (OR), 2.90; P = 0.025], stroke history (OR, 3.48; P = 0.026), obstructive CAD (OR, 3.35; P = 0.011), and thoracic aortic calcification (OR, 1.77; P = 0.005).

CONCLUSION

CTCA-WVS provides a comprehensive assessment of coronary atherosclerosis and thoracic aortic plaques in patients with CAD, which may improve the stratification of patients at risk for CV events.

Determinants of Non-calcified Low-Attenuation Coronary Plaque Burden in Patients Without Known Coronary Artery Disease: A Coronary CT Angiography Study

Background

Although epicardial adipose tissue (EAT) is associated with coronary artery disease (CAD), it is unclear whether EAT volume (EAV) can be used to diagnose high-risk coronary plaque burden associated with coronary events. This study aimed to investigate (1) the prognostic impact of low-attenuation non-calcified coronary plaque (LAP) burden on patient level analysis, and (2) the association of EAV with LAP volume in patients without known CAD undergoing coronary computed tomography angiography (CCTA).

Materials and Methods

This retrospective study consisted of 376 patients (male, 57%; mean age, 65.2 ± 13 years) without known CAD undergoing CCTA. Percent LAP volume (%LAP, <30 HU) was calculated as the LAP volume divided by the vessel volume. EAT was defined as adipose tissue with a CT attenuation value ranging from −250 to −30 HU within the pericardial sac. The primary endpoint was a composite event of death, non-fatal myocardial infarction, and unstable angina and worsening symptoms requiring unplanned coronary revascularization >3 months after CCTA. The determinants of %LAP (Q4) were analyzed using a multivariable logistic regression model.

Results

During the follow-up period (mean, 2.2 ± 0.9 years), the primary endpoint was observed in 17 patients (4.5%). The independent predictors of the primary endpoint were %LAP (Q4) (hazard ratio [HR], 3.05; 95% confidence interval [CI], 1.09–8.54; p = 0.033] in the Cox proportional hazard model adjusted by CAD-RADS category. Cox proportional hazard ratio analysis demonstrated that %LAP (Q4) was a predictor of the primary endpoint, independnet of CAD severity, Suita score, EAV, or CACS. The independent determinants of %LAP (Q4) were CACS ≥218.3 (p < 0.0001) and EAV ≥125.3 ml (p < 0.0001). The addition of EAV to CACS significantly improved the area under the curve (AUC) to identify %LAP (Q4) than CACS alone (AUC, EAV + CACS vs. CACS alone: 0.728 vs. 0.637; p = 0.013).

Conclusions

CCTA-based assessment of EAV, CACS, and LAP could help improve personalized cardiac risk management by administering patient-suited therapy.

Reverse Takotsubo Cardiomyopathy as a Cause of Acute Chest Pain in a Young Woman Following COVID-19 Vaccination

Supplemental Digital Content is available in the text.

Epicardial adipose tissue volume is associated with low-attenuation plaque volume in subjects with or without increased visceral fat: a 3-vessel coronary artery analysis with CT angiography

Background

Low-attenuation plaque (LAP) with a CT value of less than or equal 30 HU on coronary CT angiography (CCTA) is a marker of high-risk plaque features that leads to future acute coronary syndromes. Perivascular and epicardial adipose tissue (EAT) have been shown to be associated with progression of high-risk coronary plaques through metabolic and inflammatory mechanisms. However, association of EAT with LAP volume in three coronary arteries in subjects with or without visceral obesity remain unclear.

Aims

This study aimed to investigate the association of EAT volume (EAV) and coronary 3-vessel LAP volume in subjects with or without visceral obesity who underwent CCTA.

Methods

Patients who underwent CCTA without known coronary artery disease were included in the study (525 patients). Study subjects were classified as having non-obstructive or obstructive coronary artery disease according to the degree of coronary artery stenosis on CCTA. The plaque volume and EAV of the main vessel of the left anterior descending artery, left circumflex artery, and right coronary artery were measured with VINCENT software. Coronary plaque composition was classified as calcified plaque (CP, &gt;150HU), noncalcified plaque (NCP, 30–150HU), and Lap (&lt;30HU). The %LAP volume of the three coronary arteries was classified into quartiles. Multiple logistic regression analysis was used to analyze the factors associated with the %LAP volume.

Results

Compared with subjects without increase visceral fat, subjects with increased visceral fat had a significantly higher BMI, a greater total plaque volume, a greater total %LAP volume, a greater EAV, and a lower mean CT value of EAT. A significant correlation was observed between EAV and %LAP volume (R=0.24, p&lt;0.001). EAV (odds ratio; 1.83, 95% confidence interval 1.071–3.141, p-value 0.027) and type 2 diabetes mellitus (odds ratio 1.76, 95%confidence interval 1.042–3.000, p-value 0.034) appeared to be independent predictors of %LAP volume (Q4), when adjusted by age, gender, BMI&gt;25 kg/m2, visceral fat &gt;100cm2, LogCRP, coronary artery calcium score&gt;300, and obstructive coronary artery disease requiring revascularization.

Conclusion

This study suggests that LAP volume, which reflects the high-risk plaques in the three coronary arteries, is associated with EAV in subjects with or without increased visceral fat. Further research is needed whether pharmacological therapeutic intervention enables the prevention of coronary plaque progression and destabilization through the reduction of EAV in patients.

Funding Acknowledgement

Type of funding sources: None.

Clinical significance of aortic arch plaques simultaneously assessed with coronary atherosclerosis on cardiovascular outcomes in patients undergoing coronary CT angiography

Aims

Computed tomography (CT) coronary angiography is a useful diagnostic imaging modality in assessing presence, severity, and extent of coronary artery disease (CAD). Aortic arch plaques have been shown to be an underlying cause of embolic stroke and also related to increased risk of cardiovascular events. Yet, conventional CTCA imaging protocol does not include aortic arch for the reduction of radiation exposure. This study aimed to investigate prevalence of aortic arch plaques simultaneously assessed by CTCA and their clinical significance in combination with the presence of obstructive CAD for prediction of CVD events in patients with suspected CAD.

Methods

This study consisted of 310 (mean age, 66 years old, 42% female) patients with suspected CAD undergoing CTCA between 2017 and 2019. All CTCA examination was performed with 320-row detector scanner using ECG-triggered prospective gating method. Aortic arch images were simultaneously acquired during CTCA scanning without an increase of contrast media. Using Agatston method, coronary artery calcium score (CACS) was categorized into either of the groups having CACS of 0, 0–99, 100–299, or more than 300. The presence of CAD was reported as non-obstructive or obstructive CAD. High-risk featured aortic plaque was defined as large plaques &gt;4 mm in thickness showing ulceration or protrusion. A composite event of cardiovascular disease, including all-cause mortality, non-fatal myocardial infarction, unplanned hospitalization requiring revascularization or stroke was defined as the primary endpoint.

Results

Patients having CACS of 0, 0–99, 100–299, and &gt;300 were found in 41%, 24%, 15%, 20%%, respectively, where obstructive CAD was diagnosed in 11%. Aortic HRPs in ascending aorta, aortic arch, and thoracic descending aorta were observed in 1.6%, 6.9%, and 15%, respectively. During a mean follow-up period of 2.2 years, the primary endpoint was observed in 27 patients (8.7%). Cox regression hazard model demonstrated an independent association of aortic arch high-risk plaques (HR; 3.2, 95% CI; 1.20–8.64, p=0.02) and obstructive CAD (HR; 3.3, 95% CI; 1.45–7.92, P=0.005) when adjusted by age, CACS, and chronic kidney disease. Kaplan-Meier curve analysis showed a worse outcome of patients with aortic HRP and obstructive CAD compared to those without aortic plaques and obstructive CAD (p&lt;0.001).

Conclusion

This study demonstrated an independent association of aortic arch high-risk featured plaques with CVD events. Further study is warranted whether pharmacological interventional therapies can reduce future CVD risks in patients with CAD and aortic arch plaques.

Funding Acknowledgement

Type of funding sources: None.

Polarimetric Signatures of Coronary Thrombus in Patients With Acute Coronary Syndrome

BACKGROUND

Intravascular polarization-sensitive optical frequency domain imaging (PS-OFDI) offers a novel approach to measure tissue birefringence, which is elevated in collagen and smooth muscle cells, that in turn plays a critical role in healing coronary thrombus (HCT). This study aimed to quantitatively assess polarization properties of coronary fresh and organizing thrombus with PS-OFDI in patients with acute coronary syndrome (ACS).Methods and Results:The POLARIS-I prospective registry enrolled 32 patients with ACS. Pre-procedural PS-OFDI pullbacks using conventional imaging catheters revealed 26 thrombus-regions in 21 patients. Thrombus was manually delineated in conventional OFDI cross-sections separated by 0.5 mm and categorized into fresh thrombus caused by plaque rupture, stent thrombosis, or erosion in 18 thrombus-regions (182 frames) or into HCT for 8 thrombus-regions (141 frames). Birefringence of coronary thrombus was compared between the 2 categories. Birefringence in HCTs was significantly higher than in fresh thrombus (∆n=0.47 (0.37-0.72) vs. ∆n=0.25 (0.17-0.29), P=0.007). In a subgroup analysis, when only using thrombus-regions from culprit lesions, ischemic time was a significant predictor for birefringence (ß (∆n)=0.001 per hour, 95% CI [0.0002-0.002], P=0.023).

CONCLUSIONS

Intravascular PS-OFDI offers the opportunity to quantitatively assess the polarimetric properties of fresh and organizing coronary thrombus, providing new insights into vascular healing and plaque stability.

Intracoronary polarimetry for characterizing coronary plaque vulnerability in patients with coronary artery disease

Background

Intracoronary polarimetry with polarization-sensitive (PS-) optical frequency domain imaging (OFDI) measures polarization properties, including birefringence and depolarization, in parallel with structural features of conventional OFDI (Figure 1A). Collagen, which imparts mechanical integrity to fibrous caps, and collagen-synthesizing smooth muscle cells exhibit elevated birefringence. Depolarization is increased by the presence of macrophages and lipid/necrotic cores.

Purpose

This study aimed to compare conventional OFDI and polarimetric signatures of coronary lesions between patients with acute coronary syndrome (ACS) and chronic coronary syndrome (CCS). Furthermore, we aimed to determine a birefringence cut-off value for identifying which fibrous caps belong to ACS culprit lesions.

Methods

This study consisted of 37 patients with ACS (n=23) or CCS (n=14). ACS culprit lesions (ACS-lesions) and CCS stenotic lesions (CCS-lesions) were included in the analysis (820 mm). Qualitative and quantitative conventional OFDI analysis included the presence of plaque rupture, macrophage infiltration, micro-vessels, thrombus, stenosis severity, fibrous cap thickness (FCT), lipid arc, lipid-burden and calcium-burden index. Birefringence and depolarization of the coronary lesions and fibrous caps were measured in the cross-sectional images showing the minimum FCT or minimum luminal area. Predictors of ACS-lesions were investigated by multivariate regression analysis. Receiver operating characteristic (ROC) analysis was used to determine the birefringence cut-off value identifying ACS fibrous caps (ACS-caps).

Results

There were no significant differences in clinical characteristics between the two groups, except for previous history of coronary artery disease. Compared to CCS-lesions, ACS-lesions featured higher lipid-burden index and maximum lipid arc (both p&lt;0.05). ACS-lesions featured lower birefringence and higher depolarization than CCS-lesions (p&lt;0.05). Multivariable regression demonstrated an independent association of birefringence with ACS-lesions (p&lt;0.05), even after adjusting for the conventional OFDI findings. Limiting the analysis to the fibrous caps, ACS-caps exhibited significantly lower birefringence (p&lt;0.05) and higher depolarization (p&lt;0.05) that CCS-caps. ROC analysis for differentiating ACS-caps from CCS-caps found that a birefringence value of 0.0004 results in a sensitivity and specificity of 88% and 82%, respectively (Figure 1B, AUC = 0.82).

Conclusions

Intracoronary polarimetry provides quantitative assessment of coronary lesions related to their composition. Birefringence was an independent robust predictor of ACS-lesions. Decreased birefringence and pronounced depolarization within the ACS-caps may indicate increased collagenolytic activity and macrophage infiltration, respectively. These results suggest that polarization properties may serve as quantitative imaging markers for assessing plaque vulnerability.

Figure 1

Funding Acknowledgement

Type of funding source: Other. Main funding source(s): This work was supported by the National Institutes of Health and by Terumo Corporation.

Polarization-sensitive OFDI findings of vascular tissue response following drug-eluting stent implantation in patients with coronary artery disease

 

Intravascular polarimetry (IVP) with polarization-sensitive (PS-) optical frequency domain imaging (OFDI) measures polarization properties of the coronary arterial wall in parallel with the conventional OFDI images (Figure 1A). Tissues rich in collagen and smooth muscle cells (SMCs) appear birefringent, while the presence of lipid and macrophages causes depolarization. Because drug-eluting stents (DES) are designed to prevent SMC proliferation and collagen deposition, we hypothesized that neointimal tissue would exhibit low birefringence. The accumulation of lipid-laden macrophages characteristic of neoatherosclerosis should result in notable depolarization.

Methods

This study included 19 DES imaged with PS-OFDI in 13 patients (median follow-up period of 1.5 years). Coronary segments stented &gt;90 days were analyzed every 1 mm. We analyzed polarization properties of the neointima in a total of 455 frames, and in additional 97 frames of native atherosclerosis remote from the stented segments. Neointima, delineated by the lumen and the inner boundary of the stent, was manually segmented in the intensity images using MATLAB. The median birefringence in all areas of the segmented neointima featuring a depolarization of ≤0.2 and the median depolarization across the entire neointima were computed for each frame after masking the guidewire shadow. Frames presenting intensity features of macrophages, lipid or calcifications extending to at least one adjacent frame were classified as neoatherosclerosis (n=112), and otherwise as normal neointima (n=343). For comparison with neoatherosclerosis, polarization properties of native atherosclerosis (n=97) were measured. We also categorized all frames of a stented segment according to the presence of in-stent restenosis (ISR) and/or stent thrombosis (ST) (204 frames from 5 patients). A generalized linear model using a generalized estimating equation or one-way ANOVA was used for statistical analysis.

Results

The major findings of the present study are: 1) neoatherosclerosis exhibited lower birefringence than native atherosclerosis (p&lt;0.001, Figure-1B); 2) depolarization was positively associated with neoatherosclerosis (β=0.86, p&lt;0.001) and ISR/ST (β=0.72, p=0.002), while birefringence was not (Figure 1C); 3) birefringence was positively correlated with the duration after DES implantation (β=5.22×10–3, p&lt;0.001, Figure 1D). For the detection of neointimas within stents with ISR, the best cut-off value for depolarization was 0.033 with a sensitivity of 77% and a specificity of 57% (AUC=0.72). For comparison, using only conventional OFDI parameters to detect stents with ISR, the AUC were 0.52 for calcium area, 0.62 for lipid arc, and 0.63 for macrophage accumulations.

Conclusions

This study suggests that IVP provides quantitative assessment of vascular healing after DES implantation and may help clinical decision making in patients at high risk of stent failure.

Figure 1

Funding Acknowledgement

Type of funding source: Public grant(s) – National budget only. Main funding source(s): This work was supported by the National Institutes of Health.

Intravascular Polarimetry: Clinical Translation and Future Applications of Catheter-Based Polarization Sensitive Optical Frequency Domain Imaging

Optical coherence tomography (OCT) and optical frequency domain imaging (OFDI) visualize the coronary artery wall and plaque morphology in great detail. The advent of these high-resolution intracoronary imaging modalities has propelled our understanding of coronary atherosclerosis and provided enhanced guidance for percutaneous coronary intervention. Yet, the lack of contrast between distinct tissue types and plaque compositions impedes further elucidation of the complex mechanisms that contribute to acute coronary syndrome (ACS) and hinders the prospective identification of plaques susceptible to rupture. Intravascular polarimetry with polarization-sensitive OFDI measures polarization properties of the coronary arterial wall using conventional intravascular imaging catheters. The quantitative polarization metrics display notable image contrast between several relevant coronary plaque microstructures that are difficult to identify with conventional OCT and OFDI. Tissues rich in collagen and smooth muscle cells exhibit birefringence, while lipid and macrophages cause depolarization. In this review, we describe the basic principles of intravascular polarimetry, discuss the interpretation of the polarization signatures, and outline promising avenues for future research and clinical implications.

Physiological 18F-FDG uptake in the normal adult anal canal: evaluation by PET/CT

OBJECTIVE

Despite their benefit for detecting primary tumors, data for normal ¹⁸F-fluoro-2-deoxy-D-glucose (FDG) uptake in the anal canal are insufficient. Here we used positron emission tomography-computed tomography (PET/CT) to determine the uptake of FDG in the normal adult anal canal (AC) and to evaluate its clinical significance compared with that of anal cancer.

METHODS

We conducted a retrospective study of-PET/CT images in the anal region, of 201 consecutive patients without symptoms or pathology taken from January 2015 to August 2019, after excluding two patients (one each with Crohn's disease and hemorrhoid). These patients were included in the normal group, and data of eight patients with anal cancer were collected from January 2011 to August 2019 for comparison. FDG uptake was quantitatively evaluated (compared with the maximum standardized uptake value [SUV_max] to the SUV_max values of liver and distal rectum) and qualitatively (compared with background) in early and delayed phases. Normal grade 3 uptake was qualitatively defined as FDG uptake higher than the surrounding muscles.

RESULTS

In the normal group, mean anal canal SUV_max of early phase was: 2.26 (range 1.00-6.30), and delayed phase: 2.52 (range 1.00-8.80). Their ratios to liver SUV_max were early: 0.74 (range 0.24-2.25), and delayed: 0.81 (range 0.23-2.32); ratios to rectal SUV_max were early: 0.87 (range 0.30-1.89), and delayed: 0.90 (range 0.30-1.27). Qualitatively, 25 patients (15.4%) had normal grade 3 uptake during the early and delayed phases. In contrast, qualitative data showed that all patients with anal cancer exhibited high FDG uptake in the anal canal. The mean early- and delayed-phase values of SUV_max of the anal canal and anal cancer group were 11.09 (range 5.40-17.73) and 14.23 (range 6.70-22.85), respectively. There was a significant difference between the mean-early and -delayed anal SUV_max values of the normal grade 3 and anal cancer groups. Furthermore, the ratios to liver SUV_max were significantly different between the two groups.

CONCLUSIONS

PET/CT scans occasionally showed high FDG uptake in the anal canal of healthy adults. Comparing the SUV_max values of liver FDG uptake may help differentiate between normal tissue and anal cancer.

Biomechanical Stress Profiling of Coronary Atherosclerosis: Identifying a Multifactorial Metric to Evaluate Plaque Rupture Risk

OBJECTIVES

The purpose of this study was to derive a biomechanical stress metric that was based on the multifactorial assessment of coronary plaque morphology, likely related to the propensity of plaque rupture in patients.

BACKGROUND

Plaque rupture, the most frequent cause of coronary thrombosis, occurs at locations of elevated tensile stress in necrotic core fibroatheromas (NCFAs). Finite element modeling (FEM), typically used to calculate tensile stress, is computationally intensive and impractical as a clinical tool for locating rupture-prone plaques. This study derived a multifactorial stress equation (MSE) that accurately computes peak stress in NCFAs by combining the influence of several morphological parameters.

METHODS

Intravascular ultrasound and optical frequency domain imaging were conducted in 30 patients, and plaque morphological parameters were defined in 61 NCFAs. Multivariate regression analysis was applied to derive the MSE and compute a peak stress metric (PSM) that was based on the analysis of plaque morphological parameters. The accuracy of the MSE was determined by comparing PSM with FEM-derived peak stress values. The ability of the PSM in locating plaque rupture sites was tested in 3 additional patients.

RESULTS

The following parameters were found to be independently associated with peak stress: fibrous cap thickness (p < 0.0001), necrotic core angle (p = 0.024), necrotic core thickness (p < 0.0001), lumen area (p < 0.0001), necrotic core including calcium areas (p = 0.017), and plaque area (p = 0.003). The PSM showed excellent correlation (R = 0.85; p < 0.0001) with FEM-derived peak stress, thus confirming the accuracy of the MSE. In only 56% (n = 34) of plaques, the thinnest fibrous cap thickness was a determining parameter in identifying the cross section with highest PSM. In coronary segments with plaque ruptures, the MSE precisely located the rupture site.

CONCLUSIONS

The MSE shows potential to calculate the PSM in coronary lesions rapidly. However, further studies are warranted to investigate the use of biomechanical stress profiling for the prognostic evaluation of patients with atherosclerosis.

P176 Left ventricular diastolic function by gated myocardial perfusion SPECT strongly reflects NT-ProBNP

Background

The importance of left ventricle diastolic dysfunction (LVDD) has been recognized widely, as it is well established that heart failure with preserved ejection fraction has a poor prognosis. Furthermore, N-terminal pro–B-type natriuretic peptide (NT-ProBNP) is used as a marker of heart failure. However, the association between LVDD and NT-proBNP is unclear. 

Purpose

The aim of this study was to clarify the association between LVDD and NT-ProBNP. 

Methods

In this study, an index based on gated myocardial perfusion SPECT using CardioREPO software for the diagnosis of LVDD was used. Out of the 171 patients who underwent myocardial perfusion imaging (MPI) between January 2015 and December 2018, 163 individuals (116 men and 47 women) completed MPI and NT-ProBNP. Patients were classified into 4 groups: NT-ProBNP levels below 125 pg/ml (n = 52), NT-ProBNP levels 125 to 400 pg/ml (n = 33), NT-ProBNP levels 400 to 900 pg/ml (n = 23), and NT-ProBNP levels over 900 pg/ml (n = 37). CardioREPO parameters (peak filling rate　(PFR), 1/3 mean filling rate (MFR), and time to peak filling rate/R-R (TTPFR)) were compared between the 4 NT-ProBNP groups. 

Results

Of the 163 patients, 55 had LVDD. The PFR and 1/3MFR were associated with LVDD. There was a statistically significant difference in PFR and 1/3 MFR between the NT-ProBNP levels below 125 pg/ml group and the NT-ProBNP levels 400 to 900 pg/ml group (PFR = 2.51+/-1.11 vs. 1.80+/-0.65, p = 0.001; 1/3 MFR = 1.41+/-0.55 vs. 1.06+/-0.47, p = 0.006, Table).

Conclusions

The MPI indices obtained by CardioREPO software were useful in the diagnosis of LVDD. The evaluation of LVDD by MPI correlated with NT-Pro BNP level is thought to have a clinical utility in the diagnosis and management of LVDD.

Variable: NT-ProBNP 　 0-125 (n = 52) 125-400 (n = 33) 400-900 (n = 23) 900- (n = 37) p Age 66 ± 11 72 ± 11 68 ± 17 70 ± 12 0.133 Male 40 (77%) 22 (12%) 18 (78%) 23 (62%) 0.36 Left ventricular diastolic dysfunction 8 (15%) 4 (12%) 10 (43%) 27 (73%) &lt;0.001 E/A 0.9 ± 0.3 0.8 ± 0.2 1.1 ± 0.7 1.4 ± 0.9 (35) &lt;0.001 E/e" 10.27 ± 3.69 (20) 8.83 ± 3.56 (10) 12.46 ± 3.75 (12) 20.25 ± 8.30 (25) &lt;0.001 rest-PFR /s 2.51 ± 1.11 2.06 ± 0.58 2.16 ± 0.65 1.80 ± 0.65 0.001 rest-1/3 MFR /s 1.41 ± 0.55 1.19 ± 0.41 1.16 ± 0.50 1.06 ±0.47 0.008 rest-TTPFR ms 177 ± 53 181 ± 69 198 ± 80 166 ± 85 0.38 rest-TTPFR / R-R 　 0.19 ± 0.06 0.20 ± 0.11 0.21 ±0.09 0.21 ± 0.15 0.92

Intravascular Polarimetry for Tissue Characterization of Coronary Atherosclerosis

The microscopic tissue structure and organization influence the polarization of light. Intravascular polarimetry leverages this compelling intrinsic contrast mechanism by using polarization-sensitive optical frequency domain imaging to measure the polarization properties of the coronary arterial wall. Tissues rich in collagen and smooth muscle cells appear birefringent, while the presence of lipid causes depolarization, offering quantitative metrics related to the presence of important components of coronary atherosclerosis. Here, we review the basic principle, the interpretation of polarization signatures, and first clinical investigations of intravascular polarimetry and discuss how this extension of contemporary intravascular imaging may advance our knowledge and improve clinical practice in the future.

Intravascular Polarimetry in Patients With Coronary Artery Disease

OBJECTIVES

The aims of this first-in-human pilot study of intravascular polarimetry were to investigate polarization properties of coronary plaques in patients and to examine the relationship of these features with established structural characteristics available to conventional optical frequency domain imaging (OFDI) and with clinical presentation.

BACKGROUND

Polarization-sensitive OFDI measures birefringence and depolarization of tissue together with conventional cross-sectional optical frequency domain images of subsurface microstructure.

METHODS

Thirty patients undergoing polarization-sensitive OFDI (acute coronary syndrome, n = 12; stable angina pectoris, n = 18) participated in this study. Three hundred forty-two cross-sectional images evenly distributed along all imaged coronary arteries were classified into 1 of 7 plaque categories according to conventional OFDI. Polarization features averaged over the entire intimal area of each cross section were compared among plaque types and with structural parameters. Furthermore, the polarization properties in cross sections (n = 244) of the fibrous caps of acute coronary syndrome and stable angina pectoris culprit lesions were assessed and compared with structural features using a generalized linear model.

RESULTS

The median birefringence and depolarization showed statistically significant differences among plaque types (p < 0.001 for both, one-way analysis of variance). Depolarization differed significantly among individual plaque types (p < 0.05), except between normal arteries and fibrous plaques and between fibrofatty and fibrocalcified plaques. Caps of acute coronary syndrome lesions and ruptured caps exhibited lower birefringence than caps of stable angina pectoris lesions (p < 0.01). In addition to clinical presentation, cap birefringence was also associated with macrophage accumulation as assessed using normalized SD.

CONCLUSIONS

Intravascular polarimetry provides quantitative metrics that help characterize coronary arterial tissues and may offer refined insight into coronary arterial atherosclerotic lesions in patients.

Ankle-brachial index, arterial stiffness, and biomarkers in the prediction of mortality and outcomes in patients with end-stage kidney disease

BACKGROUND

Although ankle-brachial index (ABI) and brachial-ankle pulse wave velocity (baPWV) are significant predictors of major adverse cardiovascular event (MACE), their prognostic value in association with biomarkers has not been fully evaluated in patients with end-stage kidney disease (ESKD).

HYPOTHESIS

We hypothesized that ABI/baPWV would provide better prognostic value independent of biomarkers in ESKD patients.

METHODS

This study included 104 ESKD patients treated with maintenance hemodialysis who underwent ABI and baPWV examinations and laboratory tests, including brain-natriuretic peptide, high-sensitive cardiac troponin T (hs-cTnT), and high-sensitive C-reactive protein (hs-CRP). MACE was defined as a composite event of all-cause death, acute coronary syndrome, and stroke.

RESULTS

During a mean follow-up of 3.6 ± 1.7 years, a total of 51 MACE were observed. The independent factors associated with MACE were age >75 years (adjusted hazard ratio [HR], 2.15; P < .05), abnormal ABI (adjusted HR, 2.01; P < .05), left ventricular ejection fraction (LVEF) <50% (adjusted HR, 3.33; P < .001), the upper tertile of hs-cTnT (adjusted HR, 2.77; P < .05), and hs-CRP (HR, 1.96; P < .05). However, baPWV did not remain as an independent predictor of MACE in the entire cohort and also in patients without abnormal ABI. The combination of predictors improves the predictive value of MACE, providing increased HR with 4.00 for abnormal ABI + hs-CRP, 4.42 for abnormal ABI + hs-cTnT, and 7.04 for abnormal ABI + LVEF <50% (all P < .001).

CONCLUSION

Abnormal ABI is a robust predictor of MACE independent of biomarkers and their combination provides better risk stratification compared with a single predictor in ESKD patients.

Coronary Plaque Microstructure and Composition Modify Optical Polarization: A New Endogenous Contrast Mechanism for Optical Frequency Domain Imaging

OBJECTIVES

This study aimed to evaluate whether polarimetry, performed using a modified optical frequency domain imaging (OFDI) system, can improve the assessment of histological features relevant to characterizing human coronary atherosclerosis.

BACKGROUND

The microscopic structure and organization of the arterial wall influence the polarization of the infrared light used by OFDI. Modification of the OFDI apparatus, along with recently developed image reconstruction methods, permits polarimetric measurements simultaneously with conventional OFDI cross-sectional imaging through standard intravascular imaging catheters.

METHODS

The main coronary arteries of 5 cadaveric human hearts were imaged with an OFDI system capable of providing polarimetric assessment. Cross-sectional views of tissue birefringence, measured in refractive index units, and depolarization, expressed as the ratio of depolarized signal to total intensity, were reconstructed, together with conventional OFDI images. Following imaging, the vessels underwent histological evaluation to enable interpretation of the observed polarization features of individual tissue components.

RESULTS

Birefringence in fibrous tissue was significantly higher than in intimal tissue with minimal abnormality (0.44 × 10-3 vs. 0.33 × 10-3; p < 0.0001). Birefringence was highest in the tunica media (p < 0.0001), consistent with its high smooth muscle cell content, cells known to associate with birefringence. In fibrous areas, birefringence showed fine spatial features and close correspondence with the histological appearance of collagen. In contrast, necrotic cores and regions rich in lipid elicited significant depolarization (p < 0.0001). Depolarization was also evident in locations of cholesterol crystals and macrophages.

CONCLUSIONS

Intravascular measurements of birefringence and depolarization can be obtained using conventional OFDI catheters in conjunction with a modified console and signal processing algorithms. Polarimetric measurements enhance conventional OFDI by providing additional information related to the tissue composition and offer quantitative metrics enabling characterization of plaque features.

Optic axis mapping with catheter-based polarization-sensitive optical coherence tomography

Birefringence offers an intrinsic contrast mechanism related to the microstructure and arrangement of fibrillary tissue components. Here we present a reconstruction strategy to recover not only the scalar amount of birefringence but also its optic axis orientation as a function of depth in tissue from measurements with catheter-based polarization sensitive optical coherence tomography. A polarization symmetry constraint, intrinsic to imaging in the backscatter direction, facilitates the required compensation for wavelength-dependent transmission through system elements, the rotating catheter, and overlying tissue layers. Applied to intravascular imaging of coronary atherosclerosis in human patients, the optic axis affords refined interpretation of plaque architecture.

Repeatability Assessment of Intravascular Polarimetry in Patients

Intravascular polarimetry with polarization sensitive optical frequency domain imaging (PS-OFDI) measures polarization properties of the vessel wall and offers characterization of coronary atherosclerotic lesions beyond the cross-sectional image of arterial microstructure available to conventional OFDI. A previous study of intravascular polarimetry in cadaveric human coronary arteries found that tissue birefringence and depolarization provide valuable insight into key features of atherosclerotic plaques. In addition to various tissue components, catheter and sample motion can also influence the polarization of near infrared light as used by PS-OFDI. This paper aimed to evaluate the robustness and repeatability of imaging tissue birefringence and depolarization in a clinical setting. 30 patients scheduled for percutaneous coronary intervention at the Erasmus Medical Center underwent repeated PS-OFDI pullback imaging, using commercial imaging catheters in combination with a custom-built PS-OFDI console. We identified 274 matching cross sections among the repeat pullbacks to evaluate the reproducibility of the conventional backscatter intensity, the birefringence, and the depolarization signals at each spatial location across the vessel wall. Bland-Altman analysis revealed best agreement for the birefringence measurements, followed by backscatter intensity, and depolarization, when limiting the analysis to areas of meaningful birefringence. Pearson correlation analysis confirmed highest correlation for birefringence (0.86), preceding backscatter intensity (0.83), and depolarization (0.78). Our results demonstrate that intravascular polarimetry generates robust maps of tissue birefringence and depolarization in a clinical setting. This outcome motivates the use of intravascular polarimetry for future clinical studies that investigate polarization properties of arterial atherosclerosis.

Associations of sensitive cardiac troponin-I with left ventricular morphology, function and prognosis in end-stage renal disease patients with preserved ejection fraction

Sensitive cardiac troponin I (cTnI) predicts all-cause and cardiovascular mortality in various clinical settings. However, its clinical significance in hemodialysis (HD) patients with preserved left ventricular ejection fraction (LVEF) has not been fully elucidated. This study investigated the association of cTnI with LV morphology and function, and its long-term outcome in HD patients with preserved LVEF. This prospective study consists of 96 HD patients with preserved LVEF (69 ± 8 years and 63% male) who underwent two-dimensional echocardiographic examination and biomarker tests including cTnI, brain natriuretic peptide, and high-sensitive C-reactive protein. The primary endpoint was all-cause death and secondary endpoint was cardiovascular death. Factors independently associated with cTnI were systolic blood pressure (β = - 0.239, p = 0.011), heart rate (β = 0.216, p = 0.021), LV mass index (β = 0.231, p = 0.020), and E to e' ratio (β = 0.237, p = 0.016). During a mean follow-up of 3.6 years, primary and secondary endpoints were observed in 23 (24%) and 18 (19%) patients, respectively. In the multivariate Cox proportional hazard analysis, the upper cTnI tertile has significantly increased risk of all-cause mortality [hazard ratio (HR), 2.69; 95% confidence interval (CI), 1.139-6.386; p = 0.024] and that of cardiovascular death (HR, 4.56; 95% CI 2.021-16.968; p = 0.006) independent of echocardiographic measures and other serum biomarkers. In HD patients with preserved LVEF, serum cTnI levels were significantly associated with diastolic function and risk of mortality independent of echocardiographic variables and other biomarkers.