Functional Coronary Lesion Severity Research Articles

Assessment of the functional severity of coronary lesions from optical coherence tomography based on ensembled learning

BackgroundAtherosclerosis is one of the most frequent cardiovascular diseases. The dilemma faced by physicians is whether to treat or postpone the revascularization of lesions that fall within the intermediate range given by an invasive fractional flow reserve (FFR) measurement. The paper presents a monocentric study for lesions significance assessment that can potentially cause ischemia on the large coronary arteries.MethodsA new dataset is acquired, comprising the optical coherence tomography (OCT) images, clinical parameters, echocardiography and FFR measurements collected from 80 patients with 102 lesions, with stable multivessel coronary artery disease. Having the ground truth given by the invasive FFR measurement, the dataset is challenging because almost 40% of the lesions are in the gray zone, having an FFR value between 0.75 and 0.85. Twenty-six features are extracted from OCT images, clinical characteristics, and echocardiography and the most relevant are identified by examining the models’ accuracy. An ensembled learning is performed for solving the binary classification problem of lesion significance considering the leave-one-out cross-validation approach.ResultsEnsemble models are designed from the multi-features voting from 5 features models by prediction aggregation with a maximum accuracy of 81.37% and a maximum area under the curve score (AUC) of 0.856.ConclusionsThe proposed explainable supervised learning-based lesion classification is a new method that can be improved by training with a larger multicenter dataset for further designing a tool for guiding the decision making of the clinician for the cases outside the gray zone and for the other situation extra clinical information about the lesion is needed.

Diagnostic performance of computational fluid dynamics (CFD)-based fractional flow reserve (FFR) derived from coronary computed tomographic angiography (CCTA) for assessing functional severity of coronary lesions.

Fractional flow reserve (FFR) is the gatekeeper for lesion-specific revascularization decision-making in patients with stable coronary artery disease (CAD). The potential of noninvasive calculation of FFR from coronary computed tomographic angiography (CCTA) to identify ischemia-causing lesions has not been sufficiently assessed. The objective of this study was to evaluate the feasibility and diagnostic accuracy of a novel computational fluid dynamics (CFD)-based technology, termed as AccuFFRct, for the diagnosis of functionally significant lesions from CCTA, using wire-based FFR as a reference standard. A total of 191 consecutive patients who underwent CCTA and FFR measurement for suspected or known CAD were retrospectively enrolled at 2 medical centers. Three-dimensional anatomic model of coronary tree was extracted from CCTA data, CFD was applied subsequently with a novel strategy for the computation of FFR in a blinded fashion by professionals. Results were compared to invasive FFR, a threshold of ≤0.80 was used to indicate the hemodynamically relevant stenosis. On a per-patient basis, the overall accuracy, sensitivity, specificity of AccuFFRct for detecting ischemia were 91.78% (95% CI: 86.08% to 95.68%), 92.31% (95% CI: 81.46% to 97.86%) and 91.49% (95% CI: 83.92% to 96.25%), respectively; those for per-vessel basis were 91.05% (95% CI: 86.06% to 94.70%), 92.73% (95% CI: 82.41% to 97.98%) and 90.37% (95% CI: 84.10% to 94.77%), respectively. The AccuFFRct and FFR was well correlated on per-patient (r=0.709, P<0.001) and per-vessel basis (r=0.655, P<0.001). The AUC of AccuFFRct determination was 0.935 (95% CI: 0.881 to 0.969) and 0.927 (95% CI: 0.880 to 0.960) on per-patient and per-vessel basis. This novel CFD-based CCTA-derived FFR shows good diagnostic performance for detecting hemodynamic significance of coronary stenoses and may potentially become a new gatekeeper for invasive coronary angiography (ICA).

Functional assessment of myocardial ischaemia by intracoronary ECG

IntroductionIn patients with chronic coronary syndrome, percutaneous coronary intervention targets haemodynamically significant stenoses, that is, those thought to cause ischaemia. Intracoronary ECG (icECG) detects ischaemia directly where it occurs. Thus,...

Current status of assessment of fractional flow reserve.

oronary angiography presently remains the main method for the diagnosis and instruction of epicardial coronary disease. However, precise characterization of the significance for any given stenosis is limited by the inability to identify intermediate coronary lesions responsible for ischemia. In clinical practice, in addition to the assessment of the anatomical details of vessel narrowing, a more precise assessment of the impediment to coronary blood flow has become extremely important. At present, several physiological parameters have been introduced to improve discrimination in functional coronary lesion severity during cardiac catheterization. Of these parameters, myocardial fractional flow reserve (FFR) has been the most frequently used and is being increasingly applied to assess the functional significance of intermediate lesions. FFR can provide important information, both for decision making in diagnostic angiography and for monitoring and evaluating coronary interventions.

Hyperemia-free delineation of epicardial and microvascular impairments using a basal index.

The assessment of functional coronary lesion severity using intracoronary hemodynamic parameters like the pressure-derived fractional flow reserve and the flow-derived coronary flow reserve are known to rely critically on the establishment of maximal hyperemia. We evaluated a hyperemia-free index, basal pressure drop coefficient (bCDP), that combines pressure and velocity for simultaneous assessment of the status of both epicardial and microvascular circulations. In 23 pigs, simultaneous measurements of distal coronary arterial pressure and flow were performed using a dual-sensor tipped guidewire in the settings of both normal and abnormal microcirculation with the presence of epicardial lesions of area stenosis (AS) < 50% and AS > 50%. The bCDP, a parameter based on fundamental fluid dynamics principles, was calculated as the transtenotic pressure-drop divided by the dynamic pressure in the distal vessel, measured under baseline (without hyperemia) conditions. The group mean values of bCDP for normal (84 ± 18) and abnormal (124.5 ± 15.6) microcirculation were significantly different. Similarly, the mean values of bCDP from AS < 50% (72.5 ± 16.1) and AS > 50% (136 ± 17.2) were also significantly different (p < 0.05). The bCDP could significantly distinguish between lesions of AS < 50% to AS > 50% under normal microcirculation (52.1 vs. 85.8; p < 0.05) and abnormal microcirculation (84.9 vs. 172; p < 0.05). Further, the bCDP correlated linearly and significantly with the hyperemic parameters FFR (r = 0.42, p < 0.05) and CDP (r = 0.50, p < 0.05). The bCDP is a promising clinical diagnostic parameter that can independently assess the severity of epicardial stenosis and microvascular impairment. We believe that it has an immediate appeal for detection of coronary artery disease if validated clinically.

RADIONUCLIDE QUANTITATIVE IN ASSESSMENT OF MYOCARDIAL BLOOD FLOW

The aim of this study were to develop a radionuclide method for quantitative estimation of the myocardial blood flow (MBF). Twelve patients with suspected coronary artery disease underwent both Tc-99mmethoxyisobutylisonitrile (MIBI) imaging and coronary arterial injection of Tc-99m-radioalbumin macroaggregates (MAA). The myocardial uptake and MBF obtained using radionuclide angiocardiography and relative distributions of Tc-99m-MIBI were compared with the obtained using whole body with MAA as the gold standard. The myocardial uptake and MBF measured by MIBI imaging showed a good linear correlation with the myocardial uptake and MBF measured by MAA. These results indicate that MBF may be estimated by Tc-99m-MIBI imaging and can be used for the early detection and estimation of the functional severity of coronary lesions.

Editorial The time has come to move from coronary angiography to physiological assessment of coronary lesions

Editorial The time has come to move from coronary angiography to physiological assessment of coronary lesions

Response to Michiels et al and Sen et al Regarding Article, “Diagnostic Accuracy of Combined Intracoronary Pressure and Flow Velocity Information During Baseline Conditions: Adenosine-Free Assessment of Functional Coronary Lesion Severity”

Response to Michiels et al and Sen et al Regarding Article, “Diagnostic Accuracy of Combined Intracoronary Pressure and Flow Velocity Information During Baseline Conditions: Adenosine-Free Assessment of Functional Coronary Lesion Severity”

Letter by Michiels et al Regarding Article, “Diagnostic Accuracy of Combined Intracoronary Pressure and Flow Velocity Information During Baseline Conditions: Adenosine-Free Assessment of Functional Coronary Lesion Severity”

We read with interest the article by van de Hoef and colleagues about the value of the coronary stenosis pressure drop-flow velocity ratio (ΔP/V) in the evaluation of coronary stenosis.1 We congratulate the authors with this meticulous and well-written investigational report; however, we have a number of comments. Again (as with iFR in the recently published ADVISE study),2 the authors claim in their subtitle that they demonstrate the diagnostic performance of an adenosine-free assessment of functional coronary lesion severity. In recent literature, there seems to be an unjustified quest for proving that on one hand (very) high doses of intracoronary adenosine are necessary to …

Letter by Sen et al Regarding Article, “Diagnostic Accuracy of Combined Intracoronary Pressure and Flow Velocity Information During Baseline Conditions: Adenosine-Free Assessment of Functional Coronary Lesion Severity”

We read with great interest the study by van de Hoef et al1 demonstrating the ability of the hyperemia-free Basal Stenosis Resistance index to detect ischemia. This is the second study in recent months to report that the hemodynamic significance of a coronary stenosis can be assessed without the administration of potent vasodilators.2 We believe that this is a highly significant observation, which may lead to a paradigm shift reversing the a priori …

Diagnostic Accuracy of Combined Intracoronary Pressure and Flow Velocity Information During Baseline Conditions

The assessment of functional coronary lesion severity using intracoronary physiological parameters such as coronary flow velocity reserve and the more widely used fractional flow reserve relies critically on the establishment of maximal hyperemia. We evaluated the diagnostic accuracy of the stenosis resistance index during nonhyperemic conditions, baseline stenosis resistance index, compared with established hyperemic intracoronary hemodynamic parameters, because achievement of hyperemia can be cumbersome in daily clinical practice. A total of 232 patients, including 299 lesions (mean stenosis diameter 55%±11%), underwent myocardial perfusion scintigraphy for documentation of reversible perfusion defects. Distal coronary pressure and flow velocity were assessed with sensor-equipped guidewires during baseline and maximal hyperemia, induced by an intracoronary bolus of adenosine (20-40 µg). We determined stenosis resistance (SR) during baseline and hyperemic conditions as well as fractional flow reserve and coronary flow velocity reserve. The discriminative value for myocardial ischemia on myocardial perfusion scintigraphy of all parameters was compared using receiver-operating-characteristic curves. Baseline SR showed good agreement with myocardial perfusion scintigraphy. The diagnostic performance of baseline SR (area under the curve, 0.77; 95% CI, 0.71-0.83) was as accurate as fractional flow reserve and coronary flow velocity reserve (area under the curve, 0.77; 95% CI, 0.71-0.83 and area under the curve, 0.75; 95% CI, 0.68-0.81 respectively; P>0.05 compared with baseline SR for both). However, hyperemic SR, combining both pressure and flow velocity information during hyperemia, was superior to all other parameters (area under the curve, 0.81; 95% CI, 0.76-0.87; P<0.05 compared with all other parameters). Combined pressure and flow velocity measurements during baseline conditions may provide a useful tool for functional lesion severity assessment without the need for potent vasodilators.

Role of fractional and coronary flow reserve in clinical decision making in intermediate coronary lesions

Adequate patient selection for percutaneous coronary intervention is of the greatest importance in order to minimize early and late complications. Therefore, objective evidence for myocardial ischemia is mandatory for the management of patients with coronary artery disease, in particular in multivessel disease and those with intermediate lesions (40–70% diameter stenosis on angiography). The use of sensor-equipped guidewires for the assessment of functional coronary lesion severity has become extensive in the cardiac catheterization laboratory. The hemodynamic indices derived from intracoronary pressure or flow measurements, fractional flow reserve and coronary flow reserve, show a high agreement with noninvasive stress testing. Furthermore, deferral of percutaneous coronary intervention for hemodynamically nonsignificant lesions is associated with a low major adverse cardiac event rate. However, since these indices are based on either intracoronary pressure or flow, they do not investigate the hemodynami...

Quantitative Assessment of Regional Myocardial Flow Reserve Using Tc-99m-Sestamibi Imaging-Comparison With Results of O-15 Water PET-

The aims of this study were to develop a method for quantitative estimation of the myocardial blood flow index (MBFI) and myocardial flow reserve (MFR) of the whole left ventricle using (99m)technetium (Tc-99m)-sestamibi imaging. Twenty-two patients with suspected coronary artery disease and 7 controls underwent both Tc-99m-sestamibi imaging and O-15 water positron emission tomography (PET). The global MBFI was calculated on the basis of the microsphere model from the ratio of the myocardial count to the area under the time - activity curve on the aortic arch. The regional MBFI was calculated from the relative distributions of Tc-99m-sestamibi uptake values. The regional MBFI and MFR (Tc-MFR) obtained using single-photon emission computed tomography were compared with the myocardial blood flow (MBF) and MFR (PET-MFR) obtained using PET as the gold standard. Regional MBFI significantly correlated with the MBF obtained using PET. Regional Tc-MFR also correlated with the regional PET-MFR, with some underestimation. These results indicate that regional MBF and MFR may be estimated by dynamic Tc-99m-sestamibi imaging and can be used for the early detection and estimation of the functional severity of coronary lesions without the need for a PET camera.

Rationale of combined intracoronary pressure and flow velocity measurements.

The routine use of sensor-tipped guide wires for the assessment of functional coronary lesion severity has become widespread in the catheterization laboratory. The physiological parameters derived from pressure or flow velocity measurements, fractional flow reserve, relative and absolute coronary blood flow velocity reserve show a high agreement with noninvasive stress testing for myocardial ischemia. However, since these parameters are based on either intracoronary pressure or flow velocity, they do not investigate the hemodynamics of the coronary circulation completely, leading to ambiguous or conflicting outcomes. Only the use of simultaneously measured distal pressure and flow velocity will avoid any possible misinterpretation of the data. We have successfully used an index of stenosis resistance during maximal hyperemia to characterize the functional significance of a coronary stenosis. Recent developments in guide wire technology, currently used for research investigations, put these simultaneous measurements within clinical reach.