Kranthi Kolli | University of Cincinnati (original) (raw)

Papers by Kranthi Kolli

and functional diagnosis of ischemic coronary artery disease: a pilot study

Circulation, 2020

Background: Virtual functional assessment index (vFAI), an alternative approach for assessing hem... more Background: Virtual functional assessment index (vFAI), an alternative approach for assessing hemodynamic significance of stenosis has been shown to enhance the diagnostic performance of coronary computed tomography angiography (CCTA) based on evaluating the area under pressure drop-flow curve for a stenosis. Previously, this was assessed via computational fluid dynamics. We investigated the evaluation of vFAI from CCTA images using 3D printing and an in vitro flow loop and its efficacy as compared to the invasively measured fractional flow reserve (FFR). Methods and Results: Eighteen patients with varying degrees of coronary artery disease who underwent non-invasive CCTA scans and invasive FFR of their left anterior descending coronary artery (LAD) were included. The LAD artery was segmented and reconstructed using Mimics (Materialise inc.,). The segmented models were then 3D printed using Carbon 3D printer (Carbon Inc.,) with rigid resins. An in vitro flow circulation system repre...

Objectives and Background. Functional assessment of coronary lesion severity during cardiac cathe... more Objectives and Background. Functional assessment of coronary lesion severity during cardiac catheterization is conducted using diagnostic parameters like fractional flow reserve (FFR; pressure derived) and coronary flow reserve (CFR; flow derived). However, the complex hemodynamics of stenosis might not be sufficiently explained by either pressure or flow alone, particularly in the case of intermediate stenosis. CDP (ratio of pressure drop across a stenosis to distal dynamic pressure), a non-dimensional index derived from fundamental fluid dynamic principles based on a combination of intracoronary pressure and flow, may improve the functional assessment of coronary lesion severity. Methods. We performed a meta-analysis of seven studies, retrieved from MEDLINE and PubMed, comparing the results of FFR and CFR of the same lesions. Two studies reported functional measurements (pressure and flow) obtained in individual patients. Five studies reported two-dimensional plots of FFR vs CFR. ...

Circulation, 2017

Introduction: Primary prevention of heart disease is most appropriate in patients with high risk ... more Introduction: Primary prevention of heart disease is most appropriate in patients with high risk of coronary heart disease (CHD) events. Coronary artery calcium score (CACS) is known to be an indep...

Circulation, 2015

Background. Failure to achieve maximal hyperemia in coronary arteries during fractional flow rese... more Background. Failure to achieve maximal hyperemia in coronary arteries during fractional flow reserve (FFR) may result in under-estimation of pressure drop (ΔP) and over-estimation of FFR, and possi...

intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year... more intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year (monthly) by the American lymphatics, including experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the publishes original investigations on the physiology of the heart, blood vessels, and AJP-Heart and Circulatory Physiology

The Journal of invasive cardiology, 2015

Invasive diagnosis of coronary artery disease utilizes either anatomical or functional measuremen... more Invasive diagnosis of coronary artery disease utilizes either anatomical or functional measurements. In this study, we tested a futuristic parameter, lesion flow coefficient (LFC, defined as the ratio of percent coronary area stenosis (%AS) to the square root of the ratio of the pressure drop across the stenosis to the dynamic pressure in the throat region), that combines both the anatomical (%AS) and functional measurements (pressure and flow) for application in a clinical setting. In 51 vessels, simultaneous pressure and flow readings were obtained using a 0.014" Combowire (Volcano Corporation). Anatomical details were assessed using quantitative coronary angiography (QCA). Fractional flow reserve (FFR), coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR), and hyperemic microvascular index (HMR) were obtained at baseline and adenosine-induced hyperemia. QCA data were corrected for the presence of guidewire and then the LFC values were calculated. LFC was co...

Introduction: Wall shear stress (WSS) is an established predictor of coronary atherosclerosis pro... more Introduction: Wall shear stress (WSS) is an established predictor of coronary atherosclerosis progression. Prior studies have reported that high WSS has been associated with high-risk plaque characteristics (APCs). WSS and APCs are quantifiable by coronary CT angiography (CCTA) but to date, the relationship of coronary lesion ischemia—evaluated by fractional flow reserve (FFR)—to WSS and APCs has not been examined. Methods: WSS measures were obtained from 100 evaluable patients who underwent CCTA and invasive coronary angiography with FFR. Patients were categorized according to tertiles of mean WSS values defined as low (5-146 dyne/cm 2 ), intermediate (146-259 dyne/cm 2 ), and high (259-891 dyne/cm 2 ). Coronary ischemia was defined as FFR ≤0.80. Stenosis severity by CCTA was determined by minimal luminal diameter (MLD) at the site of greatest stenosis within a vessel. APCs by CCTA were defined as positive remodeling (PR), low attenuation plaque (LAP), and spotty calcification (SC)...

Introduction: Advances in coronary computed tomography angiography (CCTA) imaging and 3D printing... more Introduction: Advances in coronary computed tomography angiography (CCTA) imaging and 3D printing have enabled fabrication of physical models of coronary arterial geometry. Computational fluid dynamics (CFD) applied to CCTA allows determination of fractional flow reserve—or the hyperemic pressure ratio (P d /P a ) across a stenosis from a typically acquired CT (FFR CT ), and has been demonstrated to be a non-invasive “gold standard” for determining ischemia. We evaluated the influence of prescribed flow rates on P d /P a by 3D printed models compared to CFD evaluation. Methods: Prescribed flows were evaluated using an in vitro experimental flow loop with a pump circulating blood analog fluid at steady-state flow (Fig 1A). A 50% diameter stenosis (DS) model with a smooth Gaussian shape was fabricated using VeroClear rigid material in an Objet260 Connex printer. Mean proximal pressure (P a ) was maintained at 90 mm Hg using a linear flow needle valve. P d /P a at differing prescribed ...

Purpose: To develop a novel in vitro method of evaluating coronary artery ischemia using a combin... more Purpose: To develop a novel in vitro method of evaluating coronary artery ischemia using a combination of noninvasive coronary CT angiograms (CCTA) and 3D printing. Materials and Methods: Five patients with varying degrees of coronary artery disease who underwent non-invasive CCTA scans and invasive fractional flow reserve (FFR) of their left anterior descending coronary artery (LAD) were included in this study. The LAD artery was segmented and reconstructed using Mimics (Materialise). The segmented models were then 3D printed using a Carbon (Carbon Inc.,) and Objet260 Connex (Stratasys) printers with urethane methacrylate (UMA) family of rigid resins and Veroclear, respectively. An in vitro flow circulation system representative of invasive measurements in a cardiac catheterization laboratory was developed to experimentally evaluate the hemodynamic parameters of pressure and flow. Physiological coronary circulation was modelled in vitro as flow‐dependent stenosis resistance in seri...

The Journal of invasive cardiology, 2012

OBJECTIVES AND BACKGROUND Decisions based on invasive functional diagnostic measurements are ofte... more OBJECTIVES AND BACKGROUND Decisions based on invasive functional diagnostic measurements are often made in the setting of fluctuating hemodynamic variables that may alter resting or hyperemic measurements. The purpose of this investigation is to analyze the effect of myocardial contractility (CY) on invasive functional parameters. We hypothesize that the pressure drop coefficient (CDPe; ratio of pressure drop to distal dynamic pressure) and fractional flow reserve (FFR; ratio of average pressures distal and proximal to a stenosis) are not affected by fluctuations in CY and can distinguish between different severities of epicardial stenosis. METHODS Simultaneous measurements of distal coronary-arterial pressure and velocity were performed in 10 pigs using a dual-sensor tipped guidewire for heart rate (HR) <110 bpm and HR >110 bpm, in the presence of coronary lesions of <50% area stenosis (AS) and >50% AS. Variations in myocardial function and vascular resistance were indu...

DOMAIN EFFECTS IN THE FINITE/INFINITE TIME STABILITY PROPERTIES OF A VISCOUS SHEAR FLOW DISCONTIN... more DOMAIN EFFECTS IN THE FINITE/INFINITE TIME STABILITY PROPERTIES OF A VISCOUS SHEAR FLOW DISCONTINUITY

Stroke

Introduction: Deep learning is a novel machine learning approach that enables automated extractio... more Introduction: Deep learning is a novel machine learning approach that enables automated extraction and classification of imaging features. We aimed to use deep learning to enhance detection of brain infarction. Methods: Patients with acute ischemic stroke admitted to our institution between 2011-2015 were prospectively registered in an IRB-approved database. On a subset of these patients, radiologists annotated the images by marking infarct area. Data was split randomly into a training set and test set (80:20). Deep learning models, including a 3D multi-scale fully convolutional neural network, were developed and trained on the training set and independently tested on the test set. The performance of this model was compared to the expert consensus interpretation. Diagnostic test characteristics including the area under the curve (AUC) for the deep learning algorithm were calculated both at a voxel and imaging-study level. Computer-generated heat maps were created to denote the possi...

Journal of the American College of Cardiology

Advanced Engineering Materials

Journal of the American College of Cardiology

Current cardiovascular risk prediction models employ limited sets of variables which confine thei... more Current cardiovascular risk prediction models employ limited sets of variables which confine their predictive potential. Machine learning has emerged as a novel approach to handle high-dimensional datasets, but has yet to be adequately explored for its ability to enhance clinical risk prediction. We

Journal of the American Heart Association

Background The ability to accurately predict the occurrence of in‐hospital death after percutaneo... more Background The ability to accurately predict the occurrence of in‐hospital death after percutaneous coronary intervention is important for clinical decision‐making. We sought to utilize the New York Percutaneous Coronary Intervention Reporting System in order to elucidate the determinants of in‐hospital mortality in patients undergoing percutaneous coronary intervention across New York State. Methods and Results We examined 479 804 patients undergoing percutaneous coronary intervention between 2004 and 2012, utilizing traditional and advanced machine learning algorithms to determine the most significant predictors of in‐hospital mortality. The entire data were randomly split into a training (80%) and a testing set (20%). Tuned hyperparameters were used to generate a trained model while the performance of the model was independently evaluated on the testing set after plotting a receiver‐operator characteristic curve and using the output measure of the area under the curve ( AUC ) and...

JACC: Cardiovascular Interventions

Discordance between the physiological diagnostic parameters like fractional flow reserve (FFR) an... more Discordance between the physiological diagnostic parameters like fractional flow reserve (FFR) and coronary flow reserve (CFR) is related to the presence of diffuse and/or focal stenoses and the associated pressure loss due to flow disturbances. In this study, using an in silico approach, we non-

European heart journal, Jan 27, 2018

Artificial intelligence (AI) has transformed key aspects of human life. Machine learning (ML), wh... more Artificial intelligence (AI) has transformed key aspects of human life. Machine learning (ML), which is a subset of AI wherein machines autonomously acquire information by extracting patterns from large databases, has been increasingly used within the medical community, and specifically within the domain of cardiovascular diseases. In this review, we present a brief overview of ML methodologies that are used for the construction of inferential and predictive data-driven models. We highlight several domains of ML application such as echocardiography, electrocardiography, and recently developed non-invasive imaging modalities such as coronary artery calcium scoring and coronary computed tomography angiography. We conclude by reviewing the limitations associated with contemporary application of ML algorithms within the cardiovascular disease field.

JACC. Cardiovascular imaging, Jan 11, 2018

and functional diagnosis of ischemic coronary artery disease: a pilot study

Circulation, 2020

Background: Virtual functional assessment index (vFAI), an alternative approach for assessing hem... more Background: Virtual functional assessment index (vFAI), an alternative approach for assessing hemodynamic significance of stenosis has been shown to enhance the diagnostic performance of coronary computed tomography angiography (CCTA) based on evaluating the area under pressure drop-flow curve for a stenosis. Previously, this was assessed via computational fluid dynamics. We investigated the evaluation of vFAI from CCTA images using 3D printing and an in vitro flow loop and its efficacy as compared to the invasively measured fractional flow reserve (FFR). Methods and Results: Eighteen patients with varying degrees of coronary artery disease who underwent non-invasive CCTA scans and invasive FFR of their left anterior descending coronary artery (LAD) were included. The LAD artery was segmented and reconstructed using Mimics (Materialise inc.,). The segmented models were then 3D printed using Carbon 3D printer (Carbon Inc.,) with rigid resins. An in vitro flow circulation system repre...

Objectives and Background. Functional assessment of coronary lesion severity during cardiac cathe... more Objectives and Background. Functional assessment of coronary lesion severity during cardiac catheterization is conducted using diagnostic parameters like fractional flow reserve (FFR; pressure derived) and coronary flow reserve (CFR; flow derived). However, the complex hemodynamics of stenosis might not be sufficiently explained by either pressure or flow alone, particularly in the case of intermediate stenosis. CDP (ratio of pressure drop across a stenosis to distal dynamic pressure), a non-dimensional index derived from fundamental fluid dynamic principles based on a combination of intracoronary pressure and flow, may improve the functional assessment of coronary lesion severity. Methods. We performed a meta-analysis of seven studies, retrieved from MEDLINE and PubMed, comparing the results of FFR and CFR of the same lesions. Two studies reported functional measurements (pressure and flow) obtained in individual patients. Five studies reported two-dimensional plots of FFR vs CFR. ...

Circulation, 2017

Introduction: Primary prevention of heart disease is most appropriate in patients with high risk ... more Introduction: Primary prevention of heart disease is most appropriate in patients with high risk of coronary heart disease (CHD) events. Coronary artery calcium score (CACS) is known to be an indep...

Circulation, 2015

Background. Failure to achieve maximal hyperemia in coronary arteries during fractional flow rese... more Background. Failure to achieve maximal hyperemia in coronary arteries during fractional flow reserve (FFR) may result in under-estimation of pressure drop (ΔP) and over-estimation of FFR, and possi...

intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year... more intact animal to the cellular, subcellular, and molecular levels. It is published 12 times a year (monthly) by the American lymphatics, including experimental and theoretical studies of cardiovascular function at all levels of organization ranging from the publishes original investigations on the physiology of the heart, blood vessels, and AJP-Heart and Circulatory Physiology

The Journal of invasive cardiology, 2015

Invasive diagnosis of coronary artery disease utilizes either anatomical or functional measuremen... more Invasive diagnosis of coronary artery disease utilizes either anatomical or functional measurements. In this study, we tested a futuristic parameter, lesion flow coefficient (LFC, defined as the ratio of percent coronary area stenosis (%AS) to the square root of the ratio of the pressure drop across the stenosis to the dynamic pressure in the throat region), that combines both the anatomical (%AS) and functional measurements (pressure and flow) for application in a clinical setting. In 51 vessels, simultaneous pressure and flow readings were obtained using a 0.014" Combowire (Volcano Corporation). Anatomical details were assessed using quantitative coronary angiography (QCA). Fractional flow reserve (FFR), coronary flow reserve (CFR), hyperemic stenosis resistance index (HSR), and hyperemic microvascular index (HMR) were obtained at baseline and adenosine-induced hyperemia. QCA data were corrected for the presence of guidewire and then the LFC values were calculated. LFC was co...

Introduction: Wall shear stress (WSS) is an established predictor of coronary atherosclerosis pro... more Introduction: Wall shear stress (WSS) is an established predictor of coronary atherosclerosis progression. Prior studies have reported that high WSS has been associated with high-risk plaque characteristics (APCs). WSS and APCs are quantifiable by coronary CT angiography (CCTA) but to date, the relationship of coronary lesion ischemia—evaluated by fractional flow reserve (FFR)—to WSS and APCs has not been examined. Methods: WSS measures were obtained from 100 evaluable patients who underwent CCTA and invasive coronary angiography with FFR. Patients were categorized according to tertiles of mean WSS values defined as low (5-146 dyne/cm 2 ), intermediate (146-259 dyne/cm 2 ), and high (259-891 dyne/cm 2 ). Coronary ischemia was defined as FFR ≤0.80. Stenosis severity by CCTA was determined by minimal luminal diameter (MLD) at the site of greatest stenosis within a vessel. APCs by CCTA were defined as positive remodeling (PR), low attenuation plaque (LAP), and spotty calcification (SC)...

Introduction: Advances in coronary computed tomography angiography (CCTA) imaging and 3D printing... more Introduction: Advances in coronary computed tomography angiography (CCTA) imaging and 3D printing have enabled fabrication of physical models of coronary arterial geometry. Computational fluid dynamics (CFD) applied to CCTA allows determination of fractional flow reserve—or the hyperemic pressure ratio (P d /P a ) across a stenosis from a typically acquired CT (FFR CT ), and has been demonstrated to be a non-invasive “gold standard” for determining ischemia. We evaluated the influence of prescribed flow rates on P d /P a by 3D printed models compared to CFD evaluation. Methods: Prescribed flows were evaluated using an in vitro experimental flow loop with a pump circulating blood analog fluid at steady-state flow (Fig 1A). A 50% diameter stenosis (DS) model with a smooth Gaussian shape was fabricated using VeroClear rigid material in an Objet260 Connex printer. Mean proximal pressure (P a ) was maintained at 90 mm Hg using a linear flow needle valve. P d /P a at differing prescribed ...

Purpose: To develop a novel in vitro method of evaluating coronary artery ischemia using a combin... more Purpose: To develop a novel in vitro method of evaluating coronary artery ischemia using a combination of noninvasive coronary CT angiograms (CCTA) and 3D printing. Materials and Methods: Five patients with varying degrees of coronary artery disease who underwent non-invasive CCTA scans and invasive fractional flow reserve (FFR) of their left anterior descending coronary artery (LAD) were included in this study. The LAD artery was segmented and reconstructed using Mimics (Materialise). The segmented models were then 3D printed using a Carbon (Carbon Inc.,) and Objet260 Connex (Stratasys) printers with urethane methacrylate (UMA) family of rigid resins and Veroclear, respectively. An in vitro flow circulation system representative of invasive measurements in a cardiac catheterization laboratory was developed to experimentally evaluate the hemodynamic parameters of pressure and flow. Physiological coronary circulation was modelled in vitro as flow‐dependent stenosis resistance in seri...

The Journal of invasive cardiology, 2012

OBJECTIVES AND BACKGROUND Decisions based on invasive functional diagnostic measurements are ofte... more OBJECTIVES AND BACKGROUND Decisions based on invasive functional diagnostic measurements are often made in the setting of fluctuating hemodynamic variables that may alter resting or hyperemic measurements. The purpose of this investigation is to analyze the effect of myocardial contractility (CY) on invasive functional parameters. We hypothesize that the pressure drop coefficient (CDPe; ratio of pressure drop to distal dynamic pressure) and fractional flow reserve (FFR; ratio of average pressures distal and proximal to a stenosis) are not affected by fluctuations in CY and can distinguish between different severities of epicardial stenosis. METHODS Simultaneous measurements of distal coronary-arterial pressure and velocity were performed in 10 pigs using a dual-sensor tipped guidewire for heart rate (HR) <110 bpm and HR >110 bpm, in the presence of coronary lesions of <50% area stenosis (AS) and >50% AS. Variations in myocardial function and vascular resistance were indu...

DOMAIN EFFECTS IN THE FINITE/INFINITE TIME STABILITY PROPERTIES OF A VISCOUS SHEAR FLOW DISCONTIN... more DOMAIN EFFECTS IN THE FINITE/INFINITE TIME STABILITY PROPERTIES OF A VISCOUS SHEAR FLOW DISCONTINUITY

Stroke

Introduction: Deep learning is a novel machine learning approach that enables automated extractio... more Introduction: Deep learning is a novel machine learning approach that enables automated extraction and classification of imaging features. We aimed to use deep learning to enhance detection of brain infarction. Methods: Patients with acute ischemic stroke admitted to our institution between 2011-2015 were prospectively registered in an IRB-approved database. On a subset of these patients, radiologists annotated the images by marking infarct area. Data was split randomly into a training set and test set (80:20). Deep learning models, including a 3D multi-scale fully convolutional neural network, were developed and trained on the training set and independently tested on the test set. The performance of this model was compared to the expert consensus interpretation. Diagnostic test characteristics including the area under the curve (AUC) for the deep learning algorithm were calculated both at a voxel and imaging-study level. Computer-generated heat maps were created to denote the possi...

Journal of the American College of Cardiology

Advanced Engineering Materials

Journal of the American College of Cardiology

Current cardiovascular risk prediction models employ limited sets of variables which confine thei... more Current cardiovascular risk prediction models employ limited sets of variables which confine their predictive potential. Machine learning has emerged as a novel approach to handle high-dimensional datasets, but has yet to be adequately explored for its ability to enhance clinical risk prediction. We

Journal of the American Heart Association

Background The ability to accurately predict the occurrence of in‐hospital death after percutaneo... more Background The ability to accurately predict the occurrence of in‐hospital death after percutaneous coronary intervention is important for clinical decision‐making. We sought to utilize the New York Percutaneous Coronary Intervention Reporting System in order to elucidate the determinants of in‐hospital mortality in patients undergoing percutaneous coronary intervention across New York State. Methods and Results We examined 479 804 patients undergoing percutaneous coronary intervention between 2004 and 2012, utilizing traditional and advanced machine learning algorithms to determine the most significant predictors of in‐hospital mortality. The entire data were randomly split into a training (80%) and a testing set (20%). Tuned hyperparameters were used to generate a trained model while the performance of the model was independently evaluated on the testing set after plotting a receiver‐operator characteristic curve and using the output measure of the area under the curve ( AUC ) and...

JACC: Cardiovascular Interventions

Discordance between the physiological diagnostic parameters like fractional flow reserve (FFR) an... more Discordance between the physiological diagnostic parameters like fractional flow reserve (FFR) and coronary flow reserve (CFR) is related to the presence of diffuse and/or focal stenoses and the associated pressure loss due to flow disturbances. In this study, using an in silico approach, we non-

European heart journal, Jan 27, 2018

Artificial intelligence (AI) has transformed key aspects of human life. Machine learning (ML), wh... more Artificial intelligence (AI) has transformed key aspects of human life. Machine learning (ML), which is a subset of AI wherein machines autonomously acquire information by extracting patterns from large databases, has been increasingly used within the medical community, and specifically within the domain of cardiovascular diseases. In this review, we present a brief overview of ML methodologies that are used for the construction of inferential and predictive data-driven models. We highlight several domains of ML application such as echocardiography, electrocardiography, and recently developed non-invasive imaging modalities such as coronary artery calcium scoring and coronary computed tomography angiography. We conclude by reviewing the limitations associated with contemporary application of ML algorithms within the cardiovascular disease field.

JACC. Cardiovascular imaging, Jan 11, 2018