Threshold Peak Research Articles

Automated assessment of functional lung imaging with 68Ga-ventilation/perfusion PET/CT using iterative histogram analysis

PurposeFunctional lung mapping from Ga68-ventilation/perfusion (V/Q) PET/CT, which has been shown to correlate with pulmonary function tests (PFTs), may be beneficial in a number of clinical applications where sparing regions of high lung function is of interest. Regions of clumping in the proximal airways in patients with airways disease can result in areas of focal intense activity and artefact in ventilation imaging. These artefacts may even shine through to subsequent perfusion images and create a challenge for quantitative analysis of PET imaging. We aimed to develop an automated algorithm that interprets the uptake histogram of PET images to calculate a peak uptake value more representative of the global lung volume.MethodsSixty-six patients recruited from a prospective clinical trial underwent both V/Q PET/CT imaging and PFT analysis before treatment. PET images were normalised using an iterative histogram analysis technique to account for tracer hotspots prior to the threshold-based delineation of varying values. Pearson’s correlation between fractional lung function and PFT score was calculated for ventilation, perfusion, and matched imaging volumes at varying threshold values.ResultsFor all functional imaging thresholds, only FEV1/FVC PFT yielded reasonable correlations to image-based functional volume. For ventilation, a range of 10–30% of adapted peak uptake value provided a reasonable threshold to define a volume that correlated with FEV1/FVC (r = 0.54–0.61). For perfusion imaging, a similar correlation was observed (r = 0.51–0.56) in the range of 20–60% adapted peak threshold. Matched volumes were closely linked to ventilation with a threshold range of 15–35% yielding a similar correlation (r = 0.55–0.58).ConclusionsHistogram normalisation may be implemented to determine the presence of tracer clumping hotspots in Ga-68 V/Q PET imaging allowing for automated delineation of functional lung and standardisation of functional volume reporting.

A Simple Method to Create Corners for the Lookup Table-Based MOSFET Models Through Inputs and Outputs Mapping

This article presents a simple method to create corner models to capture process variations for the lookup table-based MOSFET models through inputs and outputs mapping. The electrical specifications, including the threshold voltage, peak transconductance, ON-state resistance, saturation current, and gate oxide thickness, can be fitted through five model parameters. The effectiveness of the method is demonstrated by both the FinFET model BSIM-CMG and the planar MOSFET measurement data.

Hyperkalemia excursions are associated with an increased risk of mortality and hospitalizations in hemodialysis patients.

BackgroundHyperkalemia is common among hemodialysis (HD) patients and has been associated with adverse clinical outcomes. Previous studies considered a single serum potassium (K) measurement or time-averaged values, but serum K excursions out of the target range may be more reflective of true hyperkalemia events. We assessed whether hyperkalemia excursions lead to an elevated risk of adverse clinical outcomes.MethodsUsing data from 21 countries in Phases 4–6 (2009–18) of the Dialysis Outcomes and Practice Patterns Study (DOPPS), we investigated the associations between peak serum K level, measured monthly predialysis, over a 4-month period (‘peak K’) and clinical outcomes over the subsequent 4 months using Cox regression, adjusted for potential confounders.ResultsThe analysis included 62 070 patients contributing a median of 3 (interquartile range 2–6) 4-month periods. The prevalence of hyperkalemia based on peak K was 58% for >5.0, 30% for >5.5 and 12% for >6.0 mEq/L. The all-cause mortality hazard ratio for peak K (reference ≤5.0 mEq/L) was 1.15 [95% confidence interval (CI) 1.09, 1.21] for 5.1–5.5 mEq/L, 1.19 (1.12, 1.26) for 5.6–6.0 mEq/L and 1.33 (1.23, 1.43) for >6.0 mEq/L. Results were qualitatively consistent when analyzing hospitalizations and a cardiovascular composite outcome.ConclusionsAmong HD patients, we identified a lower K threshold (peak K 5.1–5.5 mEq/L) than previously reported for increased risk of hospitalization and mortality, with the implication that a greater proportion (>50%) of the HD population may be at risk. A reassessment of hyperkalemia severity ranges is needed, as well as an exploration of new strategies for effective management of chronic hyperkalemia.

Constraining reionization in progress at z = 5.7 with Lyman-α emitters: voids, peaks, and cosmic variance

ABSTRACT A number of independent observations suggest that the intergalactic medium was significantly neutral at z = 7 and that reionization was, perhaps, still in progress at z = 5.7. The narrowband survey, SILVERRUSH, has mapped over 2000 Lyman-α emitters (LAEs) at these redshifts ( G58). Previous analyses have assumed that reionization was over by z = 5.7, but this data may actually sample the final stages of reionization when the last neutral islands were relegated to the cosmic voids. Motivated by these developments, we re-examine LAE void and peak statistics and their ability to constrain reionization. We construct models of the LAE distribution in (1 Gpc h−1)3 volumes, spanning a range of neutral fractions at z = 5.7 and 6.6. Models with a higher neutral fraction show an enhanced probability of finding holes in the LAE distribution. When comparing models at fixed mean surface density, however, LAEs obscured by neutral gas in the voids must be compensated by visible LAEs elsewhere. Hence, in these models, the likelihood of finding an overdense peak is also enhanced in the latter half of reionization. Compared to the widely used angular two-point correlation function (2PCF), we find that the void probability function (VPF) provides a more sensitive test of models during the latter half of reionization. By comparison, at neutral fractions $\sim 50{{\ \rm per\ cent}}$, the VPF and a simple peak thresholding statistic are both similar to the 2PCF in constraining power. Lastly, we find that the cosmic variance and large-scale asymmetries observed in the SILVERRUSH fields are consistent with large-scale structure in a ΛCDM universe.

Characterization of a method to study urodynamics and bladder nociception in male and female mice.

Abdominal electromyogram or visceromotor response (VMR) elicited by bladder distension is a validated as a measure of bladder nociception in mice, however it is not without its limitations. The aim of this study is to address some of these limitations and validate voiding evoked VMR as a measure of bladder nociception mice. Using both male and female C57BL/6 mice we assessed the VMR response to cytometry- induced voiding before and after instillation of 0.5% acetic acid into the bladder. We then delivered intravesical lidocaine to confirm the VMR response as nociceptive. VMR and correlative cystometric bladder pressures were analyzed. We found that the VMR can be evoked by continuous fluid infusion into the bladder of both male and female mice. This response is potentiated after bladder injury and can be attenuated by administration of a local anesthetic, providing strong evidence that this method can be used to evaluate bladder nociception. Further, evaluation of cystometric pressure traces obtained during VMR recording revealed that intercontraction intervals were not altered after bladder injury in either male or female mice. However, we did observe a decrease in peak threshold pressures after bladder injury in female mice, which could be rescued by lidocaine administration. In conclusion, this technique can measure the VMR and bladder nociception associated with voiding in both female and male mice. Although confounds still exist with the use of anesthesia, further exploration of non-anesthetized voiding-evoked VMR is warranted.

The acute physiological and perceptual effects of recovery interval intensity during cycling-based high-intensity interval training

PurposeThe current study sought to investigate the role of recovery intensity on the physiological and perceptual responses during cycling-based aerobic high-intensity interval training.MethodsFourteen well-trained cyclists (dot{V}{text{O}}_{{{text{2peak}}}}: 62 ± 9 mL kg−1 min−1) completed seven laboratory visits. At visit 1, the participants’ peak oxygen consumption (dot{V}{text{O}}_{{{text{2peak}}}}) and lactate thresholds were determined. At visits 2–7, participants completed either a 6 × 4 min or 3 × 8 min high-intensity interval training (HIIT) protocol with one of three recovery intensity prescriptions: passive (PA) recovery, active recovery at 80% of lactate threshold (80A) or active recovery at 110% of lactate threshold (110A).ResultsThe time spent at > 80%, > 90% and > 95% of maximal minute power during the work intervals was significantly increased with PA recovery, when compared to both 80A and 110A, during both HIIT protocols (all P ≤ 0.001). However, recovery intensity had no effect on the time spent at > 90% dot{V}{text{O}}_{{{text{2peak}}}} (P = 0.11) or > 95% dot{V}{text{O}}_{{{text{2peak}}}} (P = 0.50) during the work intervals of both HIIT protocols. Session RPE was significantly higher following the 110A recovery, when compared to the PA and 80A recovery during both HIIT protocols (P < 0.001).ConclusionPassive recovery facilitates a higher work interval PO and similar internal stress for a lower sRPE when compared to active recovery and therefore may be the efficacious recovery intensity prescription.

Laser-induced softening analysis of a hardened aluminum alloy by physical simulation

The study focuses on the analysis of the softening effects of the work-hardened aluminum alloy sheets EN AW 5754 H32 1.5 mm thick, through the physical simulation of thermal cycles induced in the material by laser heat treatments (LHTs). A numerical-experimental approach was implemented to define the laser thermal cycles and to subsequently reproduce them on the GleebleTM 3180 physical simulator. The obtained softening was measured by microhardness and metallographic analysis tests. For the definition of laser thermal cycles, preliminary tests with a 2.5 kW CO2 laser source have been realized, and a three-dimensional transient finite element thermal models were developed and calibrated with the experimental results. The investigated laser heat treatment parameters explored thermal cycles with different shape, interaction time, and peak temperature. Physical simulation tests were performed using laser thermal cycles that showed the maximum softening of the aluminum alloy. A three-dimensional transient finite element thermoelectric model was developed to design the shape of the Gleeble specimens, which satisfy the heating and cooling rate required by laser thermal cycles. Results obtained show that it is possible to physically simulate the investigated laser thermal cycles, reducing the cross section of the shaped part of the specimen. Softening effects depend on the thermal cycle shape. Greater softening is observed by increasing the interaction time and the peak temperature, but beyond a peak temperature threshold value, negligible effects are detected.

Examining the impact of inducible ischemia on myocardial fibrosis and exercise capacity in hypertrophic cardiomyopathy

Myocardial ischemia in hypertrophic cardiomyopathy (HCM) is associated with poor outcomes. Vasodilator stress cardiac magnetic resonance (CMR) can detect and quantitate inducible ischemia in HCM patients. We hypothesized that myocardial ischemia assessed by CMR is associated with myocardial fibrosis and reduced exercise capacity in HCM. In 105 consecutive HCM patients, we performed quantitative assessment of left ventricular volume and mass, wall thickness, segmental wall thickening percent, segmental late Gadolinium enhancement (LGE), and extracellular volume fraction (ECV). Time-signal intensity curves of first pass perfusion sequences were generated for each segment at stress and rest. A myocardial perfusion reserve index (MPRI) (stress/rest slope) was calculated. Patients who underwent an echocardiographic (n = 73) and cardiopulmonary exercise test (n = 37) within 30 days were included. The mean age was 53.2 ± 15.4 years; 60% were male, and 82 patients had asymmetric hypertrophy. Segments with end diastolic thickness ≥ 1.2 cm had a higher burden of LGE (4.1% vs 0.5% per segment), reduced MPRI (2.6 ± 1.5 vs 3.1 ± 1.8) and reduced thickening percent (48.9 ± 41.7% vs. 105.3 ± 59.5%), (P < 0.0001 for all comparisons). Patients with ischemia (any segment with MPRI < 2) were more likely to have dynamic left ventricular outflow tract (LVOT) obstruction (63.3% vs 36.7%, P = 0.01), to be smokers (17% vs 6.9%, P = 0.04), and had a higher ECV (30% vs 28%, P = 0.04). The total LGE burden was similar between the two groups (P = 0.47). Increasing ischemia burden (number of segments with MPRI < 2) was associated with worsened ventilatory efficiency (VE/VCO2) (P < 0.001) but not peak oxygen consumption or anerobic threshold (P > 0.2). In a patient-level multivariable logistic regression model, only LVOT obstruction remained a significant predictor of ischemia burden (P = 0.03). Myocardial ischemia by CMR is associated with myocardial segmental dysfunction and interstitial fibrosis, as assessed by ECV, in HCM patients, even in segments free of LGE. Conversely, quantitative ischemia burden was not associated with replacement fibrosis as assessed by total LGE burden. Patients with ischemia had greater prevalence of dynamic LVOT obstruction; and in a subset of patients with cardiopulmonary exercise testing, ischemia burden was associated with worsened ventilatory efficiency.

Internally stiffened foam-filled carbon fiber reinforced composite tubes under impact loading for energy absorption applications

Fiber reinforced plastics can absorb energy, in the unlikely event of a crash, on the other hand, foam improves the structural integrity of the device being filled with. Therefore, foam-filled carbon fiber reinforced plastic (CFRP) composites are extensively used as an energy absorber for safety enhancement. Current study aims to characterize the impact response of CFRP composite tubes filled with polyurethane foam with five different combinations. The CFRP tubes were internally stiffened with sheets, tubes and hats made of CFRP composite. In addition, the internally stiffened tubes were filled with polyurethane (PU) foam for structural integrity. Specimens were then tested under dynamic crushing using a drop weight impactor with an impact energy of 75 J. During the tests, the behaviors of specimens were recorded by high speed camera. Visual inspections and micrographs of the specimens were also investigated. The results revealed that the peak force, threshold force, and energy absorbed were increased by using the PU foam inside the CFRP composite tubes. The energy absorption did not show significant improvement by adding the internal CFRP reinforcements, whereas, the peak load improvement was considerable. The specimen filled with only PU foam yielded the best specific energy absorption among all the specimens.

Monolithic integration of ultraviolet microdisk lasers into photonic circuits in a III-nitride-on-silicon platform.

Ultraviolet microdisk lasers are integrated monolithically into photonic circuits using a III-nitride-on-silicon platform with gallium nitride (GaN) as the main waveguide layer. The photonic circuits consist of a microdisk and a pulley waveguide, terminated by out-coupling gratings. In this Letter, we measure quality factors up to 3500 under continuous-wave excitation. Lasing is observed from 374 to 399 nm under pulsed excitation, achieving low-threshold energies of 0.14mJ/cm2 per pulse (threshold peak powers of 35kW/cm2). A large peak-to-background dynamic of around 200 is observed at the out-coupling grating for small gaps of 50 nm between the disk and the waveguide. These devices operate at the limit of what can be achieved with GaN in terms of operation wavelength.

Statistical extrapolation methods for estimating extreme loads on wind turbine blades under turbulent wind conditions and stochastic material properties

According to the IEC Standard 61400-1, designers of wind turbines are required to apply statistical extrapolation techniques to estimate the extreme (ultimate) load. In the present article, the certification procedure is assessed under the uncertainty of the material properties using a simulated load time series of the National Renewable Energy Laboratory 5MW reference wind turbine rotor. The uncertainty of the material properties is introduced in the elastic properties of the composite materials based on the OptiDAT composite material database. The assessment relies on the comparison of the estimated blade extreme loads and deflections, obtained for the reference and the stochastically varied material properties. It is found that the variability of the material properties does not affect the estimated ultimate moments (differences &lt; 1.5%) but affects the maximum flapwise deflection (differences ~8%). It is concluded that the peak over threshold peak extraction technique and the three-parameter Weibull fitting functions outperform among those considered in the article.

Study on the matching feature of current parameters for inducing contraction of orbicularis oris muscle by artificial facial nerve in rabbit with peripheral facial paralysis

Objective: To explore the optimal matching of the current parameters about artificial facial nerve (AFN) for inducing contraction of the orbicularis oris muscle (OOM) in rabbit with peripheral facial paralysis. Methods: According to the combinations of different stimulus parameters, at different time points, we used AFN to induce contraction of the affected side OOM of the paralyzed rabbit in waking state. We recorded the current amplitudes of the threshold stimulation and peak stimulation under each combination, then compared the total charge of the stimulus consumption under different combinations. Results: Compared the total stimulus charge consumption of the AFN threshold stimulation and that in the peak stimulation respectively under different stimulus frequency and pulse width matching combinations, we found that the frequency, the pulse width and the interaction of the frequency and pulse width among different groups could affect the total charge, the differences were statistically significant (P<0.05). Conclusions: When AFN stimulus frequency is 60 Hz and the stimulus pulse width is 100 μs, the output current intensity is relatively lowest and the total consumed charge is the lowest under the premise of effectively inducing the paralytic side OOM contraction. Thus we recommend this stimulus parametric combination as the optimal combination for meeting the low power consumption of AFN.

Performance Analysis of OFDM With Peak Cancellation Under EVM and ACLR Restrictions

This paper presents performance analysis of an adaptive peak cancellation method to reduce the high peak-toaverage power ratio (PAPR) for OFDM systems, while keeping the out-of-band (OoB) power leakage as well as an in-band distortion power below the pre-determined level. In this work, the increase of adjacent leakage power ratio (ACLR) and error vector magnitude (EVM) are estimated recursively using the detected peak amplitude. We present analytical framework for OFDM-based systems with theoretical bit error rate (BER) representations and detection of optimum peak threshold based on predefined EVM and ACLR requirements. Moreover, the optimum peak detection threshold is selected based on the oretical design to maintain the predefined distortion level. Thus, their degradations are automatically restricted below the pre-defined levels which correspond to target OoB radiation. We also discuss the practical design of peak-cancellation (PC) signal with target OoB radiation and in-band distortion through optimizing the windowing size of the PC signal. Numerical results show the improvements with respect to both achievable bit error rate (BER) and PAPR with the PC method in eigen-beam space division multiplexing (E-SDM) systems under restriction of OoB power radiation. It can also be seen that the theoretical BER shows good agreements with simulation results.

A NOVEL VALIDATED UHPLC METHOD FOR ESTIMATION OF ASSAY AND ITS RELATED SUBSTANCES OF TRICHOSTATIN-A

Objective: The main objective of the research work is to develop and validate a rapid UHPLC method for the estimation of assay and its related substances of Trichostatin A (TSA) in pharmaceutical samples.&#x0D; Methods: The UHPLC method developed for chromatographic separation between TSA and its related compounds on Poroshell 120 SB C18(50×4.6) mm; 2.7 µm RRLC column using Agilent RRLC (UHPLC) system with linear gradient elution.&#x0D; Results: The developed UHPLC method has shown excellent chromatographic separation between TSA and its related compounds within 12 min run time, during validation experiments, specificity study revealed that the peak threshold was more than the peak purity and no purity flag was observed. Repeatability, intra, and inter-day precision results were well within the tolerable limits. Limits of detection concentrations were found between 0.075 to 0.077 ppm and the limit of quantitation is between 0.252 to 0.258 ppm for related compounds and TSA. The related substances method recoveries were found between 80 and 120 % and assay method recovery was found between 98.0 to 102.0%.&#x0D; Conclusion: The developed method capability was proven for the assay of TSA and its related compounds in pharmaceutical samples and the method shows eco-friendlier than routine, conventional HPLC methods in terms of analysis time, cost and HPLC effluent waste.

A Domain Adaptive Density Clustering Algorithm for Data With Varying Density Distribution

As one type of efficient unsupervised learning methods, clustering algorithms have been widely used in data mining and knowledge discovery with noticeable advantages. However, clustering algorithms based on density peak have limited clustering effect on data with varying density distribution (VDD), equilibrium distribution (ED), and multiple domain-density maximums (MDDM), leading to the problems of sparse cluster loss and cluster fragmentation. To address these problems, we propose a Domain-Adaptive Density Clustering (DADC) algorithm, which consists of three steps: domain-adaptive density measurement, cluster center self-identification, and cluster self-ensemble. For data with VDD features, clusters in sparse regions are often neglected by using uniform density peak thresholds, which results in the loss of sparse clusters. We define a domain-adaptive density measurement method based on K-Nearest Neighbors (KNN) to adaptively detect the density peaks of different density regions. We treat each data point and its KNN neighborhood as a subgroup to better reflect its density distribution in a domain view. In addition, for data with ED or MDDM features, a large number of density peaks with similar values can be identified, which results in cluster fragmentation. We propose a cluster center self-identification and cluster self-ensemble method to automatically extract the initial cluster centers and merge the fragmented clusters. Experimental results demonstrate that compared with other comparative algorithms, the proposed DADC algorithm can obtain more reasonable clustering results on data with VDD, ED and MDDM features. Benefitting from a few parameter requirements and non-iterative nature, DADC achieves low computational complexity and is suitable for large-scale data clustering.

Controlling backbreak and enhancing fragmentation in dragline bench blasting—a geo-engineering approach

Dragline bench blasting contributes to about 200 million m3 of overburden excavation in India. Large-sized bench blasts with multiple rows (8–10 nos.) and holes per row (18–20 nos.) are carried out to obtain a dragline cut measuring, typically, 80 m in width and 200 m in length. Backbreak is generally observed in such blasts, which deteriorates blasting efficiency, fragmentation, and dragline utilization. Rockmass disposition, blast design, explosive selection, and blast-induced ground vibration were found to be the key contributing factors affecting backbreak and fragmentation. In this research work, in situ P wave velocity profiles were generated using 24-channel seismic refraction tomography for competency mapping of the rockmass. Seismic tomography identified three sonically distinct layers up to a depth of 22–30 m. Near-field vibration monitoring was conducted to record ground vibration signatures using two triaxial borehole geophones installed within a distance of 40 m from the last row of the blast and the vibration levels up to 839.71 mm/s and backbreaks extending up to 9.9 m were observed. Fragmentation analysis was carried out using scaled photography and WipFrag software. Behavior of backbreak and mean fragment size with peak vector sum of ground vibration, in situ P wave velocity, and bench stiffness was examined. This was followed by development of mathematical models for predicting backbreak and mean fragment size. Suitable blast design, charging scheme, and delay configuration were suggested based on rockmass competency, threshold peak particle velocity, and desired fragmentation. The suggested pattern was implemented and found to control backbreak within 5.5 m and mean fragment size at 43.38 cm.

AIUM Practice Parameter for the Performance of an Ultrasound Examination of Solid-Organ Transplants.

AIUM Practice Parameter for the Performance of an Ultrasound Examination of Solid-Organ Transplants.

Return Period of Characteristic Discharges from the Comparison between Partial Duration and Annual Series, Application to the Walloon Rivers (Belgium)

The determination of the return period of frequent discharges requires the definition of flood peak thresholds. Unlike daily data, the volume of data to be processed with the generalization of hourly data loggers or even with an even finer temporal resolution quickly becomes too large to be managed by hand. We therefore propose an algorithm that automatically extracts flood characteristics to compute partial series return periods based on hourly series of flow rates. Thresholds are defined through robust analysis of field observation-independent data to obtain five independent flood peaks per year in order to bypass the 1-year limit of annual series. Peak over thresholds were analyzed using both Gumbel’s graphical method and his ordinary moments method. Hydrological analyses exhibit the value in the convergence point revealed by this dual method for floods with a recurrence interval around 5 years. Pebble-bedded rivers on impervious substratum (Ardenne rivers) presented an average bankfull discharge return period of around 0.6 years. In the absence of field observation, the authors have defined the bankfull discharge as the Q0.625 computed with partial series. Annual series computations allow Q100 discharge determination and extreme floods recurrence interval estimation. A comparison of data from the literature allowed for the confirmation of the value of Myer’s rating at 18, and this value was used to predict extreme floods based on the area of the watershed.

Detection algorithm of regional peak motion based on acceleration sensor

In this paper, an algorithm of regional peak motion detection based on acceleration sensor is designed. Firstly, the acceleration model is processed by triaxial integration method, and then the signal is filtered by Gaussian filter. Finally, the step result is obtained by combining regional peak detection, threshold limit and other methods. Through the analysis of the data collected by the acceleration sensor, we can extract the parameters representing the motion attitude of the object from the single-chip microcomputer system, and dynamically modify the parameter value set by the system according to the current system motion attitude, and compare the value with the current motion attitude parameter, so as to judge whether the current count is effective. At the same time, this device can be well applied in the industrial system to achieve convenient and effective counting function. The results show that the step counting algorithm in this paper has high accuracy.

Effects of ticagrelor on cardiorespiratory fitness in patients after percutaneous coronary intervention

Objective: To investigate the effects of ticagrelor on cardiorespiratory fitness in patients with coronary heart disease after percutaneous coronary intervention (PCI). Methods: A total of 1 073 patients, who were diagnosed as coronary heart disease and underwent cardiopulmonary exercise testing (CPET) within 1 year after PCI, were enrolled from September 2017 to September 2019 in Peking University Third Hospital, including 309 patients in ticagrelor group and 764 patients in clopidogrel group. Clinical information, blood test results, echocardiographic parameters, cardiorespiratory fitness related parameters (including peak oxygen uptake (VO(2)), anaerobic threshold VO(2), peak oxygen pulse (VO(2)/HR) and carbon dioxide ventilation equivalent (VE/VCO(2)) slope), coronary lesions and intervention information were obtained. Cardiopulmonary fitness related indexes were compared between the two groups, and the correlation between ticagrelor use and cardiopulmonary fitness related indexes was analyzed by multivariate logistic regression. Patients who underwent CPET within 1 month after PCI were included in the subgroup analysis. Results: In ticagrelor group, the age was (60.3±10.3) years, and 253(81.9%) cases were male. The age of clopidogrel group was (60.6±10.0) years, and there were 608(79.6%) males. No significant differences were observed in peak VO(2), anaerobic threshold VO(2), and peak VO(2)/HR between the two groups (all P>0.05), but the VE/VCO(2) slope was significantly higher in the ticagrelor group than in the clopidogrel group (30.075 (27.207, 33.603) vs. 28.853 (25.970, 32.336), P<0.001). Logistic regression analysis suggested that the peak VO(2), anaerobic threshold VO(2) and peak VO(2)/HR were not significantly correlated with the ticagrelor use (all P>0.05), while the VE/VCO(2) slope was independently correlated with ticagrelor use (OR=1.098, 95%CI 1.032-1.168, P=0.003). Subgroup analysis of patients who underwent CPET within 1 month after PCI also indicated that no significant difference were observed in peak VO(2), anaerobic threshold VO(2), peak VO(2)/HR and VE/VCO(2) slope between the two groups (all P>0.05). Logistic regression analysis suggested that the peak VO(2), anaerobic threshold VO(2) and peak VO(2)/HR were not significantly correlated with ticagrelor use (all P>0.05), while the VE/VCO(2) slope was significantly correlated with ticagrelor use (OR=1.132, 95%CI 1.030-1.244, P=0.010). Conclusion: Among coronary heart disease patients after PCI, treatment with clopidogrel does not result in significant decrease in exercise endurance as compared with patients treated with ticagrelor.