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coronary microvascular resistance

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https://www.readbyqxmd.com/read/27899365/prevalence-and-clinical-significance-of-discordant-changes-in-fractional-and-coronary-flow-reserve-after-elective-percutaneous-coronary-intervention
#1
Junji Matsuda, Tadashi Murai, Yoshihisa Kanaji, Eisuke Usui, Makoto Araki, Takayuki Niida, Sadamitsu Ichijyo, Rikuta Hamaya, Tetsumin Lee, Taishi Yonetsu, Mitsuaki Isobe, Tsunekazu Kakuta
BACKGROUND: Fractional flow reserve (FFR) and coronary flow reserve (CFR) are well-validated physiological indices; however, changes in FFR and CFR after percutaneous coronary intervention (PCI) remain elusive. We sought to evaluate these changes and to investigate whether physiological indices predict cardiac event-free survival after PCI. METHODS AND RESULTS: Physiological assessment of 220 stenoses from 220 patients was performed before and after PCI. The changes in FFR and CFR were studied, and factors associated with CFR change were investigated...
November 29, 2016: Journal of the American Heart Association
https://www.readbyqxmd.com/read/27898505/clinical-role-of-post-angioplasty-hyperemic-microvascular-resistances-in-chronic-ischemic-left-ventricular-dysfunction
#2
Riccardo Gorla, Edoardo Verna, Simone Scotti, Sergio Ghiringhelli, Laura Zoli, Stefano Provasoli, Silvana Garancini, Roberto De Ponti, Jorge A Salerno-Uriarte
AIMS: To investigate the impact of hyperemic microvascular resistances (HMRs) on myocardial perfusion and contractility after percutaneous coronary intervention (PCI) in chronic ischemic left ventricular dysfunction (CILVD). METHODS: The current retrospective study included 48 patients with CILVD of the left anterior descending territory undergoing HMRs assessment before and after PCI with a dual-sensor intracoronary pressure-flow wire. The severity of resting myocardial underperfusion and contractile dysfunction of the left anterior descending territory was scored as summed rest score (SRS-T) by single photon emission tomography, wall motion score index (WMSI-T) and left ventricular ejection fraction (LVEF) by transthoracic echocardiography before PCI and after 3 months...
November 24, 2016: Journal of Cardiovascular Medicine
https://www.readbyqxmd.com/read/27866132/a-tool-for-predicting-the-outcome-of-reperfusion-in-st-elevation-myocardial-infarction-using-age-thrombotic-burden-and-index-of-microcirculatory-resistance-ati-score
#3
Giovanni Luigi De Maria, Gregor Fahrni, Mohammad Alkhalil, Florim Cuculi, Sam Dawkins, Mathias Wolfrum, Robin P Choudhury, John C Forfar, Bernard D Prendergast, Tuncay Yetgin, Robert Jan van Geuns, Matteo Tebaldi, Keith M Channon, Rajesh K Kharbanda, Peter M Rothwell, Marco Valgimigli, Adrian P Banning
AIMS: Restoration of effective myocardial reperfusion by primary percutaneous coronary intervention (PPCI) in patients with ST-elevation myocardial infarction is difficult to predict. A method to assess the likelihood of a suboptimal response to conventional pharmacomechanical therapies could be beneficial. We aimed to derive and validate a scoring system that can be used acutely at the time of coronary reopening to predict the likelihood of downstream microvascular impairment in patients with STEMI...
November 20, 2016: EuroIntervention
https://www.readbyqxmd.com/read/27848160/coronary-flow-reserve-and-relative-flow-reserve-measured-by-n-13-ammonia-pet-for-characterization-of-coronary-artery-disease
#4
Sang-Geon Cho, Ki Seong Park, Jahae Kim, Sae-Ryung Kang, Ho-Chun Song, Ju Han Kim, Jae Yeong Cho, Young Joon Hong, Zeenat Jabin, Hee Jeong Park, Geum-Cheol Jeong, Seong Young Kwon, Jin Chul Paeng, Hyeon Sik Kim, Jung-Joon Min, Ernest V Garcia, Henry Hee-Seung Bom
OBJECTIVE: We evaluated the relationships between coronary flow reserve (CFR) and relative flow reserve (RFR) measured by N-13 ammonia positron emission tomography (PET) for characterization of epicardial coronary artery disease (CAD). METHODS: Sixty-nine consecutive stable angina patients underwent N-13 ammonia PET, coronary computed tomography angiography (CCTA), and if necessary, invasive coronary angiography (CAG) within 2 weeks. Myocardial blood flow (MBF), CFR, RFR, and coronary vascular resistance of the reference arterial territory (CVRref) were measured by N-13 ammonia PET...
November 15, 2016: Annals of Nuclear Medicine
https://www.readbyqxmd.com/read/27803036/comparative-prognostic-utility-of-indexes-of-microvascular-function-alone-or-in-combination-in-patients-with-an-acute-st-segment-elevation-myocardial-infarction
#5
David Carrick, Caroline Haig, Nadeem Ahmed, Jaclyn Carberry, Vannesa Teng Yue May, Margaret McEntegart, Mark C Petrie, Hany Eteiba, Mitchell Lindsay, Stuart Hood, Stuart Watkins, Andrew Davie, Ahmed Mahrous, Ify Mordi, Ian Ford, Aleksandra Radjenovic, Keith G Oldroyd, Colin Berry
BACKGROUND: Primary percutaneous coronary intervention is frequently successful at restoring coronary artery blood flow in patients with acute ST-segment-elevation myocardial infarction; however, failed myocardial reperfusion commonly passes undetected in up to half of these patients. The index of microvascular resistance (IMR) is a novel invasive measure of coronary microvascular function. We aimed to investigate the pathological and prognostic significance of an IMR>40, alone or in combination with a coronary flow reserve (CFR≤2...
December 6, 2016: Circulation
https://www.readbyqxmd.com/read/27771399/noninvasive-ct-derived-ffr-based-on%C3%A2-structural-and%C3%A2-fluid-analysis-a-comparison-with-invasive-ffr-for-detection-of-functionally-significant-stenosis
#6
Brian S Ko, James D Cameron, Ravi K Munnur, Dennis T L Wong, Yasuko Fujisawa, Takuya Sakaguchi, Kenji Hirohata, Jacqui Hislop-Jambrich, Shinichiro Fujimoto, Kazuhisa Takamura, Marcus Crossett, Michael Leung, Ahilan Kuganesan, Yuvaraj Malaiapan, Arthur Nasis, John Troupis, Ian T Meredith, Sujith K Seneviratne
OBJECTIVES: This study describes the feasibility and accuracy of a novel computed tomography (CT) fractional flow reserve (FFR) technique based on alternative boundary conditions. BACKGROUND: Techniques used to compute FFR based on images acquired from coronary computed tomography angiography (CTA) are described. Boundary conditions were typically determined by allometric scaling laws and assumptions regarding microvascular resistance. Alternatively, boundary conditions can be derived from the structural deformation of coronary lumen and aorta, although its accuracy remains unknown...
October 14, 2016: JACC. Cardiovascular Imaging
https://www.readbyqxmd.com/read/27767984/the-optimum-hematocrit
#7
Walter H Reinhart
The hematocrit (Hct) determines the oxygen carrying capacity of blood, but also increases blood viscosity and thus flow resistance. From this dual role the concept of an optimum Hct for tissue oxygenation has been derived. Viscometric studies using the ratio Hct/blood viscosity at high shear rate showed an optimum Hct of 50-60% for red blood cell (RBC) suspensions in plasma. For the perfusion of an artificial microvascular network with 5-70μm channels the optimum Hct was 60-70% for high driving pressures. With lower shear rates or driving pressures the optimum Hct shifted towards lower values...
October 21, 2016: Clinical Hemorheology and Microcirculation
https://www.readbyqxmd.com/read/27747373/coronary-flow-reserve-in-patients-with-resistant-hypertension
#8
Sebastian Völz, Sara Svedlund, Bert Andersson, Gan Li-Ming, Bengt Rundqvist
Resistant hypertension is associated with increased risk for cardiovascular events. Coronary flow reserve (CFR) is impaired in patients with hypertension and an independent predictor of cardiac mortality. However, there are no published data on CFR in the subset of treatment-resistant hypertension. The aim of this study was to assess CFR in patients with resistant hypertension. Twenty-five consecutive patients with primary resistant hypertension, scheduled for renal denervation, 25 matched patients with controlled hypertension, and 25 healthy controls underwent transthoracic colour Doppler echocardiography at rest and during adenosine infusion...
October 17, 2016: Clinical Research in Cardiology: Official Journal of the German Cardiac Society
https://www.readbyqxmd.com/read/27721212/randomised-trial-to-compare-a-protective-effect-of-clopidogrel-versus-ticagrelor-on-coronary-microvascular-injury-in-st-segment-elevation-myocardial-infarction-cv-time-trial
#9
Sang-Don Park, Man-Jong Lee, Yong-Soo Baek, Sung-Woo Kwon, Sung-Hee Shin, Seong-Ill Woo, Dae-Hyeok Kim, Jun Kwan, Keum-Soo Park
AIMS: Ticagrelor has shown greater, more rapid and more consistent platelet inhibition than clopidogrel. However, the superiority of ticagrelor for preventing ischaemic damage in STEMI patients has not been proven. The aim of this trial was to assess whether ticagrelor is superior to clopidogrel in preventing microvascular injury in ST-elevation myocardial infarction (STEMI). METHODS AND RESULTS: Patients with STEMI underwent prospective random assignment to receive a loading dose (LD) of clopidogrel 600 mg or ticagrelor 180 mg (1:1 ratio) before primary percutaneous coronary intervention (PCI)...
October 10, 2016: EuroIntervention
https://www.readbyqxmd.com/read/27699259/microvascular-resistance-of-the-culprit-coronary-artery-in-acute-st-elevation-myocardial-infarction
#10
David Carrick, Caroline Haig, Jaclyn Carberry, Vannesa Teng Yue May, Peter McCartney, Paul Welsh, Nadeem Ahmed, Margaret McEntegart, Mark C Petrie, Hany Eteiba, Mitchell Lindsay, Stuart Hood, Stuart Watkins, Ahmed Mahrous, Samuli M O Rauhalammi, Ify Mordi, Ian Ford, Aleksandra Radjenovic, Naveed Sattar, Keith G Oldroyd, Colin Berry
BACKGROUND: Failed myocardial reperfusion is common and prognostically important after acute ST-elevation myocardial infarction (STEMI). The purpose of this study was to investigate coronary flow reserve (CFR), a measure of vasodilator capacity, and the index of microvascular resistance (IMR; mmHg × s) in the culprit artery of STEMI survivors. METHODS: IMR (n = 288) and CFR (n = 283; mean age [SD], 60 [12] years) were measured acutely using guide wire-based thermodilution...
May 5, 2016: JCI Insight
https://www.readbyqxmd.com/read/27694191/plasma-concentration-of-serotonin-is-a-novel-biomarker-for-coronary-microvascular-dysfunction-in-patients-with-suspected-angina-and-unobstructive-coronary-arteries
#11
Yuji Odaka, Jun Takahashi, Ryuji Tsuburaya, Kensuke Nishimiya, Kiyotaka Hao, Yasuharu Matsumoto, Kenta Ito, Yasuhiko Sakata, Satoshi Miyata, Daisuke Manita, Yuji Hirowatari, Hiroaki Shimokawa
AIMS: Although the importance of coronary microvascular dysfunction (CMD) has been emerging, reliable biomarkers for CMD remain to be developed. We examined the potential usefulness of plasma concentration of serotonin to diagnose CMD in patients with suspected angina and unobstructive coronary arteries. METHODS AND RESULTS: We enrolled 198 consecutive patients (M/F 116/82, 60.2 ± 13.3 years old) who underwent acetylcholine provocation test and measured plasma serotonin concentration...
October 2, 2016: European Heart Journal
https://www.readbyqxmd.com/read/27515327/coronary-physiology-during-exercise-and-vasodilation-in-the-healthy-heart-and-in-severe-aortic-stenosis
#12
Matthew Lumley, Rupert Williams, Kaleab N Asrress, Satpal Arri, Natalia Briceno, Howard Ellis, Ronak Rajani, Maria Siebes, Jan J Piek, Brian Clapp, Simon R Redwood, Michael S Marber, John B Chambers, Divaka Perera
BACKGROUND: Severe aortic stenosis (AS) can manifest as exertional angina even in the presence of unobstructed coronary arteries. OBJECTIVES: The authors describe coronary physiological changes during exercise and hyperemia in the healthy heart and in patients with severe AS. METHODS: Simultaneous intracoronary pressure and flow velocity recordings were made in unobstructed coronary arteries of 22 patients with severe AS (mean effective orifice area 0...
August 16, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27511978/comparison-of-fractional-flow-reserve-assessment-with-demand-stress-myocardial-contrast-echocardiography-in-angiographically-intermediate-coronary-stenoses
#13
Juefei Wu, David Barton, Feng Xie, Edward O'Leary, John Steuter, Gregory Pavlides, Thomas R Porter
BACKGROUND: Real-time myocardial contrast echocardiography (RTMCE) directly measures capillary flow (CBF), which in turn is a major regulator of coronary flow and resistance during demand or hyperemic stress. Although fractional flow reserve (FFR) was developed to assess the physiological relevance of an epicardial stenosis, it assumes maximal microvascular vasodilation and minimal resistance during vasodilator stress. Therefore, we sought to determine the relationship between CBF assessed with RTMCE during stress echocardiography and FFR in intermediate coronary lesions...
August 2016: Circulation. Cardiovascular Imaging
https://www.readbyqxmd.com/read/27449710/prevalence-and-comorbidities-of-double-diabetes
#14
S R Merger, W Kerner, M Stadler, A Zeyfang, P Jehle, M Müller-Korbsch, R W Holl
BACKGROUND: A growing number of people with type 1 diabetes (T1DM) are identified with features of metabolic syndrome (MS) known as "double diabetes", but epidemiologic data on the prevalence of MS in T1DM and its comorbidities are still lacking. Aim of this cross sectional study is to better estimate the prevalence of MS in T1DM, and to assess its association with comorbidities. METHODS: Data of 31,119 persons with autoimmune diabetes mellitus were analysed for signs of MS and presence of late complications...
September 2016: Diabetes Research and Clinical Practice
https://www.readbyqxmd.com/read/27342881/the-influence-of-elective-percutaneous-coronary-intervention-on-microvascular-resistance-a-serial-assessment-using-the-index-of-microcirculatory-resistance
#15
Tadashi Murai, Tetsumin Lee, Yoshihisa Kanaji, Junji Matsuda, Eisuke Usui, Makoto Araki, Takayuki Niida, Keiichi Hishikari, Sadamitsu Ichijyo, Rikuta Hamaya, Taishi Yonetsu, Mitsuaki Isobe, Tsunekazu Kakuta
This study investigates whether hyperemic microvascular resistance (MR) is influenced by elective percutaneous coronary intervention (PCI) by using the index of microcirculatory resistance (IMR). Seventy-one consecutive patients with stable angina pectoris undergoing elective PCI were prospectively studied. The IMR was measured before and after PCI and at the 10-mo follow-up. The IMR significantly decreased until follow-up; the pre-PCI, post-PCI, and follow-up IMRs had a median of 19.8 (interquartile range, 14...
September 1, 2016: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/27291778/functional-adaptations-of-the-coronary-microcirculation-to-anaemia-in-fetal-sheep
#16
Sonnet S Jonker, Lowell Davis, Divya Soman, J Todd Belcik, Brian P Davidson, Tamara M Atkinson, Adrienne Wilburn, Samantha Louey, George D Giraud, Jonathan R Lindner
KEY POINTS: In fetuses, chronic anaemia stimulates cardiac growth; simultaneously, blood flow to the heart muscle itself is increased, and reserve blood flow capacity of the coronary vascular bed is preserved. Here we examined functional adaptations of the capillaries and small blood vessels responsible for delivering oxygen to the anaemic fetal heart muscle using contrast-enhanced echocardiography. We demonstrate that coronary microvascular flux rate doubled in anaemic fetuses compared to control fetuses, both at rest and during maximal flow, suggesting reduced microvascular resistance consistent with capillary widening...
November 1, 2016: Journal of Physiology
https://www.readbyqxmd.com/read/27274171/predictive-value-of-neutrophil-lymphocyte-ratio-and-platelet-lymphocyte-ratio-in-patients-with-coronary-slow-flow
#17
Mustafa Çetin, Emrullah Kiziltunc, Özgül Uçar Elalmış, Zehra Güven Çetin, Muhammed Bora Demirçelik, Hülya Çiçekçioğlu, Alparslan Kurtul, Selçuk Özkan, Candan Mansuroğlu Avan, Ender Örnek, Feridun Vasfi Ulusoy
BACKGROUND: Increased microvascular resistance due to chronic inflammation is assumed to be one of the mechanisms associated with coronary slow flow (CSF). Previous studies have shown that the platelet-to-lymphocyte ratio (PLR) and the neutrophil-lymphocyte ratio (NLR) are markers of inflammation for various diseases. In this study we aimed to evaluate the relationship between CSF and PLR-NLR. METHODS: Seventy-eight patients with CSF and 50 patients with normal coronary flow were enrolled into this study...
May 2016: Acta Cardiologica Sinica
https://www.readbyqxmd.com/read/27220268/suppression-of-bim-by-microrna-19a-may-protect-cardiomyocytes-against-hypoxia-induced-cell-death-via-autophagy-activation
#18
Yan-Hua Gao, Ju-Ying Qian, Zhang-Wei Chen, Ming-Qiang Fu, Jian-Feng Xu, Yan Xia, Xue-Feng Ding, Xiang-Dong Yang, Yuan-Yuan Cao, Yun-Zeng Zou, Jun Ren, Ai-Jun Sun, Jun-Bo Ge
Microvascular obstruction (MO), one of unfavorable complications of percutaneous coronary intervention (PCI), is responsible for the lost benefit of reperfusion therapy. Determination of microRNA-19a, a member of the miR-17-92 cluster, using quantitative real-time polymerase chain reaction (PCR) revealed notably down-regulated microRNA-19a, in myocardium with MO. Nonetheless, the role of miR-19a in MO and the underlying mechanism remains to be elucidated. To this end, an in vitro microembolization model in cardiomyocytes was used...
August 22, 2016: Toxicology Letters
https://www.readbyqxmd.com/read/27219714/preprocedural-fractional-flow-reserve-and-microvascular-resistance-predict-increased-hyperaemic-coronary-flow-after-elective-percutaneous-coronary-intervention
#19
Tadashi Murai, Yoshihisa Kanaji, Taishi Yonetsu, Tetsumin Lee, Junji Matsuda, Eisuke Usui, Makoto Araki, Takayuki Niida, Mitsuaki Isobe, Tsunekazu Kakuta
BACKGROUND: Epicardial focal coronary artery stenosis, diffuse coronary disease, and microvascular resistance (MR) may limit coronary flow. The purpose of percutaneous coronary intervention (PCI) is to increase coronary flow by targeting epicardial lesions. After PCI, MR might change and affect coronary flow. We investigated whether PCI influences MR using the index of microcirculatory resistance (IMR) and if pre-PCI fractional flow reserve (FFR) or MR predicts the post-PCI change in hyperaemic coronary flow...
May 24, 2016: Catheterization and Cardiovascular Interventions
https://www.readbyqxmd.com/read/27113960/index-of-microvascular-resistance-after-early-conversion-from-calcineurin-inhibitor-to-everolimus-in-heart-transplantation-a-sub-study-to-a-1-year-randomized-trial
#20
Ole Geir Solberg, Knut Stavem, Asgrimur Ragnarsson, Dan Ioanes, Satish Arora, Knut Endresen, Jūratė Šaltytė Benth, Lars Gullestad, Einar Gude, Arne K Andreassen, Lars Aaberge
BACKGROUND: Microvascular function in transplanted hearts can be evaluated by methods used in routine left heart catheterization follow-up after heart transplantation (HTx). This sub-study of a randomized study compared the effects of everolimus (EVR) and calcineurin inhibitor (CNI) treatment on microvascular function as expressed by the index of microvascular resistance (IMR) at 1 year after HTx. A secondary objective was to compare the change in IMR from 7-11 weeks to 1 year after HTx between randomized groups...
August 2016: Journal of Heart and Lung Transplantation
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