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coronary microvascular resistance

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https://www.readbyqxmd.com/read/28007742/invasive-minimal-microvascular-resistance-is-a-new-index-to-assess-microcirculatory-function-independent-of-obstructive-coronary-artery-disease
#1
Guus A de Waard, Sukhjinder S Nijjer, Martijn A van Lavieren, Nina W van der Hoeven, Ricardo Petraco, Tim P van de Hoef, Mauro Echavarría-Pinto, Sayan Sen, Peter M van de Ven, Paul Knaapen, Javier Escaned, Jan J Piek, Justin E Davies, Niels van Royen
BACKGROUND: Coronary microcirculatory dysfunction portends a poor cardiovascular outcome. Invasive assessment of microcirculatory dysfunction by coronary flow reserve (CFR) and hyperemic microvascular resistance (HMR) is affected by coronary artery disease (CAD). In this study we propose minimal microvascular resistance (mMR) as a new measure of microcirculatory dysfunction and aim to determine whether mMR is influenced by CAD. METHODS AND RESULTS: We obtained 482 simultaneous measurements of intracoronary Doppler flow velocity and pressure...
December 22, 2016: Journal of the American Heart Association
https://www.readbyqxmd.com/read/27969910/tct-543-calculation-of-serial-index-of-microvascular-resistance-with-adjusted-wedge-pressure-in-patients-with-non-st-elevation-acute-coronary-syndrome
#2
Kevin Liou, Nigel Jepson, Virag Kushwaha, Jenny Yu, Sze-Yuan Ooi
No abstract text is available yet for this article.
November 1, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27969891/tct-524-invasive-minimal-microvascular-resistance-mmr-a-new-index-to-assess-microcirculatory-dysfunction-that-is-not-modulated-by-the-presence-of-angiographic-coronary-artery-disease
#3
Guus de Waard, Sukhjinder Nijjer, Martijn van Lavieren, Nina van der Hoeven, Ricardo Petraco, Tim van de Hoef, Mauro Echavarria Pinto, Sayan Sen, Peter van de Ven, Paul Knaapen, Javier Escaned, Jan Piek, Justin Davies, Niels van Royen
No abstract text is available yet for this article.
November 1, 2016: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/27930353/bimodal-pattern-of-coronary-microvascular-involvement-in-diabetes-mellitus
#4
Murat Sezer, Mehmet Kocaaga, Emre Aslanger, Adem Atici, Ahmet Demirkiran, Zehra Bugra, Sabahattin Umman, Berrin Umman
BACKGROUND: The contribution of functionally disturbed coronary autoregulation and structurally impaired microvascular vasodilatory function to reduced coronary flow velocity reserve, reflecting impaired coronary microcirculation in diabetes mellitus (DM), has not been clearly elucidated. The objective of this study was to identify the mechanism of coronary microvascular impairment in DM in relation to duration of disease. METHODS AND RESULTS: Coronary flow velocities in the anterior descending coronary artery were assessed by transthoracic echocardiography following angiography revealing normal epicardial coronary arteries in 55 diabetic and 47 nondiabetic patients...
November 14, 2016: Journal of the American Heart Association
https://www.readbyqxmd.com/read/27926579/the-influence-of-coronary-plaque-morphology-assessed-by-optical-coherence-tomography-on-final-microvascular-function-after-stenting-in-patients-with-st-elevation-myocardial-infarction
#5
Giovanni L De Maria, Niket Patel, Mathias Wolfrum, Gregor Fahrni, George Kassimis, Italo Porto, Sam Dawkins, Robin P Choudhury, John C Forfar, Bernard D Prendergast, Keith M Channon, Rajesh K Kharbanda, Hector M Garcia-Garcia, Adrian P Banning
OBJECTIVES: The index of microcirculatory resistance (IMR) provides a reproducible assessment of the status of coronary microvasculature in patients with ST-elevation myocardial infarction (STEMI). Frequency-domain optical coherence tomography (FD-OCT) enables detailed assessment of the morphology of coronary plaque.We sought to determine the influence of the initial culprit coronary plaque anatomy within the infarct-related artery on IMR after stenting in STEMI. PATIENTS AND METHODS: In 25 STEMI patients IMR was measured immediately before and after stent implantation...
December 6, 2016: Coronary Artery Disease
https://www.readbyqxmd.com/read/27899365/prevalence-and-clinical-significance-of-discordant-changes-in-fractional-and-coronary-flow-reserve-after-elective-percutaneous-coronary-intervention
#6
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
#7
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
#8
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
#9
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
#10
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
#11
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
#12
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
#13
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
#14
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
#15
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
#16
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
#17
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
#18
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
#19
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
#20
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
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