Publications by authors named "Nieman K"
Left Atrial Volumetric/Mechanical Coupling Index: Best of Both Worlds?
J Am Soc Echocardiogr
November 2024
Background: Recent photon-counting computed tomography (PCCT) development brings great opportunities for plaque characterization with much-improved spatial resolution and spectral imaging capability. While existing coronary plaque PCCT imaging results are based on CZT- or CdTe-materials detectors, deep-silicon photon-counting detectors offer unique performance characteristics and promise distinct imaging capabilities.
Purpose: This study aims to numerically investigate the feasibility of characterizing plaques with a deep-silicon PCCT scanner and to demonstrate its potential performance advantages over traditional CT scanners using energy-integrating detectors (EID).
Article Synopsis
- Non-invasive simulations for coronary hemodynamics enhance clinical decision-making and outcomes for patients with coronary artery disease, but existing methods often overlook individual patient differences and uncertainties in data.
- The study introduces an uncertainty-aware pipeline that personalizes coronary flow simulations and predicts clinical outcomes with greater accuracy by integrating patient-specific coronary flows and addressing data uncertainties.
- Utilizing advanced statistical methods, including adaptive Markov Chain Monte Carlo sampling and a novel combination of multi-fidelity Monte Carlo estimation, the framework demonstrates improved precision and reduced uncertainty in estimating cardiac functions and coronary flows compared to traditional methods.
Background CT-derived fractional flow reserve (CT-FFR) and dynamic CT myocardial perfusion imaging enhance the specificity of coronary CT angiography (CCTA) for ruling out coronary artery disease (CAD). However, evidence on comparative diagnostic value remains scarce. Purpose To compare the diagnostic accuracy of CCTA plus CT-FFR, CCTA plus CT perfusion, and sequential CCTA plus CT-FFR and CT perfusion for detecting hemodynamically relevant CAD with that of invasive angiography.
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- A study examined the relationship between how completely patients with stable angina were revascularized (opened blocked arteries) and their cardiovascular health outcomes, using a method called fractional flow reserve (FFR) to measure artery health.
- In 900 patients, those who were incompletely revascularized had a significantly higher risk of cardiovascular events, like heart attacks, compared to those who were completely revascularized or had normal FFR readings.
- The findings suggest that ensuring complete revascularization in patients with critical artery blockages (FFR ≤ 0.80) could lead to better heart health outcomes.
Article Synopsis
- - The current clinical practice utilizes qualitative and semi-quantitative measures to assess coronary artery disease via cardiac CT, but advancements in technology are paving the way for more quantitative approaches.
- - Quantitative coronary CT angiography offers significant potential benefits for both patient management and research in the field of cardiology.
- - This document seeks to establish clear definitions and standards for how quantitative measures of coronary artery disease should be performed and reported using cardiac CT.
Coronary computed tomography angiography (cCTA) has poor specificity to identify coronary stenosis that limit blood flow to the myocardial tissue. Integration of dynamic CT myocardial perfusion imaging (CT-MPI) can potentially improve the diagnostic accuracy. We propose a method that integrates cCTA and CT-MPI to identify culprit coronary lesions that limit blood flow to the myocardium.
View Article and Find Full Text PDFComputational simulations of coronary artery blood flow, using anatomical models based on clinical imaging, are an emerging non-invasive tool for personalized treatment planning. However, current simulations contend with two related challenges - incomplete anatomies in image-based models due to the exclusion of arteries smaller than the imaging resolution, and the lack of personalized flow distributions informed by patient-specific imaging. We introduce a data-enabled, personalized and multi-scale flow simulation framework spanning large coronary arteries to myocardial microvasculature.
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- - Traditional clinical risk scores for atherosclerosis do not reliably predict major adverse cardiovascular events (MACE) due to individual complexities in disease predisposition.
- - Advances in coronary computed tomography angiography (CCTA) have enhanced the ability to accurately quantify and characterize atherosclerotic plaques, showing improved prognostic value for MACE across diverse populations.
- - Serial studies using CCTA may deepen our understanding of atherosclerosis progression and could be combined with other risk markers to improve MACE prevention, though more extensive randomized trials are needed.
Article Synopsis
- The study investigated how smoking status affects the coronary volume-to-myocardial mass ratio (V/M) in individuals with coronary artery disease (CAD) who underwent CT analysis.
- It included a sample of 2,874 participants, revealing that former smokers had higher coronary volume than never-smokers, while current smokers had greater myocardial mass but both groups exhibited lower V/M ratios compared to never-smokers.
- The findings suggest that both current and former smoking status are significant predictors of lower V/M, alongside other factors like diabetes and severity of coronary stenosis.
Article Synopsis
- - The study examines the relationship between luminal stenosis, computed tomography-derived fractional-flow reserve (FFR), and high-risk plaque features on coronary CT angiography, focusing on their impact on patient outcomes and plaque volume measurements.
- - Data from 4,430 patients were analyzed using artificial intelligence to assess coronary plaque and determine optimal plaque volume cutoffs, considering factors like age, sex, hypertension, and diabetes.
- - Results showed that patients with total plaque volume and percent atheroma volume above specific cutoffs faced higher risks of major adverse cardiac events and late revascularization within one year.
Background: The association between coronary computed tomography angiography (CTA) derived fractional flow reserve (FFR) and risk of recurrent angina in patients with new onset stable angina pectoris (SAP) and stenosis by CTA is uncertain.
Methods: Multicenter 3-year follow-up study of patients presenting with symptoms suggestive of new onset SAP who underwent first-line CTA evaluation and subsequent standard-of-care treatment. All patients had at least one ≥30 % coronary stenosis.
Objectives: To compare cardiac computed tomography (CCT) and cardiac magnetic resonance (CMR) for the quantitative assessment of the left ventricular (LV) trabeculated layer in patients with suspected noncompaction cardiomyopathy (NCCM).
Materials And Methods: Subjects with LV excessive trabeculation who underwent both CMR and CCT imaging as part of the prospective international multicenter NONCOMPACT clinical study were included. For each subject, short-axis CCT and CMR slices were matched.
Unlabelled: Background CT is helpful in guiding the revascularization of chronic total occlusion (CTO), but manual prediction scores of percutaneous coronary intervention (PCI) success have challenges. Deep learning (DL) is expected to predict success of PCI for CTO lesions more efficiently. Purpose To develop a DL model to predict guidewire crossing and PCI outcomes for CTO using coronary CT angiography (CCTA) and evaluate its performance compared with manual prediction scores.
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- - This study aimed to evaluate how coronary CT angiography (CCTA) and derived fractional flow reserve (FFR) are used clinically to assess coronary artery disease (CAD) in patients with diabetes mellitus (DM) compared to those without DM.
- - The analysis included 4,290 participants and found that patients with DM tended to have more severe CAD conditions, but both groups shared similar rates of treatment changes based on CT-FFR results and coronary revascularization.
- - Ultimately, while DM was linked to higher risk of adverse cardiovascular events over a year, it didn't significantly increase risk when accounting for the severity of arterial blockages.
Background The prognostic value of coronary CT angiography (CTA)-derived fractional flow reserve (FFR) beyond 1-year outcomes and in patients with high levels of coronary artery calcium (CAC) is uncertain. Purpose To assess the prognostic value of coronary CTA-derived FFR test results on 3-year clinical outcomes in patients with coronary stenosis and among a subgroup of patients with high levels of CAC. Materials and Methods This study represents a 3-year follow-up of patients with new-onset stable angina pectoris who were consecutively enrolled in the Assessing Diagnostic Value of Noninvasive CT-FFR in Coronary Care, known as ADVANCE (ClinicalTrials.
View Article and Find Full Text PDFComputational simulations of coronary artery blood flow, using anatomical models based on clinical imaging, are an emerging non-invasive tool for personalized treatment planning. However, current simulations contend with two related challenges - incomplete anatomies in image-based models due to the exclusion of arteries smaller than the imaging resolution, and the lack of personalized flow distributions informed by patient-specific imaging. We introduce a data-enabled, personalized and multi-scale flow simulation framework spanning large coronary arteries to myocardial microvasculature.
View Article and Find Full Text PDFObjectives: To develop a tool including exercise electrocardiography (ExECG) for patient-specific clinical likelihood estimation of patients with suspected obstructive coronary artery disease (CAD).
Methods: An ExECG-weighted clinical likelihood (ExECG-CL) model was developed in a training cohort of patients with suspected obstructive CAD undergoing ExECG. Next, the ExECG-CL model was applied in a CAD validation cohort undergoing ExECG and clinically driven invasive coronary angiography and a prognosis validation cohort and compared with the risk factor-weighted clinical likelihood (RF-CL) model for obstructive CAD discrimination and prognostication, respectively.
Low mental energy can contribute to decreased productivity, altered life balance, decreased physical performance, and ultimately affect quality of life. As such, there is a great demand for food and beverage products that positively impact mental energy. Numerous products claim to alter mental energy making continued review of the scientific evidence critical.
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- Collateral arteries serve as natural bypasses that maintain blood flow during artery blockages, and enhancing their development could be a potential treatment for cardiac ischemia.
- Research using imaging and modeling on neonate and adult mouse hearts revealed that neonate collaterals are more effective at restoring blood flow compared to those in adults.
- In adults, the growth of coronary arteries involved adding branches rather than increasing size, leading to reduced effectiveness, highlighting the difference in collateral artery functionality between fetal and adult hearts and emphasizing their importance for heart regeneration and therapeutic strategies.
The coronary vascular volume to left ventricular mass (V/M) ratio assessed by coronary computed tomography angiography (CCTA) is a promising new parameter to investigate the relation of coronary vasculature to the myocardium supplied. It is hypothesized that hypertension decreases the ratio between coronary volume and myocardial mass by way of myocardial hypertrophy, which could explain the detected abnormal myocardial perfusion reserve reported in patients with hypertension. Individuals enrolled in the multicenter ADVANCE (Assessing Diagnostic Value of Noninvasive FFRCT in Coronary Care) registry who underwent clinically indicated CCTA for analysis of suspected coronary artery disease with known hypertension status were included in current analysis.
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- The study examined the link between body mass index (BMI), coronary artery disease (CAD), and clinical outcomes using the ADVANCE Registry data.
- Out of 5014 patients, those with obesity were generally younger, had more comorbidities, but had less obstructive CAD compared to normal and overweight patients.
- Despite these differences, the risk of major cardiovascular events was similar across all BMI categories, indicating that obesity does not affect the overall risk of these events.
Coronary computed tomographic angiography (CCTA) is becoming the first-line investigation for establishing the presence of coronary artery disease and, with fractional flow reserve (FFR), its haemodynamic significance. In patients without significant epicardial obstruction, its role is either to rule out atherosclerosis or to detect subclinical plaque that should be monitored for plaque progression/regression following prevention therapy and provide risk classification. Ischaemic non-obstructive coronary arteries are also expected to be assessed by non-invasive imaging, including CCTA.
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