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coronary microvascular resistance

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https://www.readbyqxmd.com/read/29025901/effects-of-age-and-exercise-training-on-coronary-microvascular-smooth-muscle-phenotype-and-function
#1
Judy M Muller-Delp, Kazuki Hotta, Bei Chen, Bradley Jon Behnke, Joshua J Maraj, Michael D Delp, Tiffani R Lucero, Jeremy A Bramy, David B Alarcon, Hannah E Morgan, Morgan R Cowan, Anthony D Haynes
Coronary microvascular function and blood flow responses during acute exercise are impaired in the aged heart, but can be restored by exercise training. Coronary microvascular resistance is directly dependent on vascular smooth muscle function in coronary resistance arterioles; therefore, we hypothesized that age impairs contractile function and alters the phenotype of vascular smooth muscle in coronary arterioles. We further hypothesized that exercise training restores contractile function and reverses age-induced phenotypic alterations of arteriolar smooth muscle...
October 12, 2017: Journal of Applied Physiology
https://www.readbyqxmd.com/read/28990847/obstructive-sleep-apnoea-from-respiratory-events-to-coronary-microvascular-dysfunction
#2
Sofia Morra, François Roubille
Obstructive sleep apnoea (OSA) is an emerging and independent risk factor for cardiovascular diseases; coronary artery disease (CAD) is higher in OSA patients, even in the absence of other traditional cardiovascular risk factors. There is little evidence to show abnormalities in coronary blood flow (CBF) and disorders in coronary vascular resistance (CVR), occurring during the obstructive respiratory event, suggesting coronary microvascular dysfunction (CMD) as a potential mechanism of ischaemic heart disease (IHD) OSA-as a related consequence...
October 9, 2017: Acta Cardiologica
https://www.readbyqxmd.com/read/28984631/right-ventricular-perfusion-physiology-and-clinical-implications
#3
George J Crystal, Paul S Pagel
Regulation of blood flow to the right ventricle differs significantly from that to the left ventricle. The right ventricle develops a lower systolic pressure than the left ventricle, resulting in reduced extravascular compressive forces and myocardial oxygen demand. Right ventricular perfusion has eight major characteristics that distinguish it from left ventricular perfusion: (1) appreciable perfusion throughout the entire cardiac cycle; (2) reduced myocardial oxygen uptake, blood flow, and oxygen extraction; (3) an oxygen extraction reserve that can be recruited to at least partially offset a reduction in coronary blood flow; (4) less effective pressure-flow autoregulation; (5) the ability to downregulate its metabolic demand during coronary hypoperfusion and thereby maintain contractile function and energy stores; (6) a transmurally uniform reduction in myocardial perfusion in the presence of a hemodynamically significant epicardial coronary stenosis; (7) extensive collateral connections from the left coronary circulation; and (8) possible retrograde perfusion from the right ventricular cavity through the Thebesian veins...
October 4, 2017: Anesthesiology
https://www.readbyqxmd.com/read/28920099/fast-virtual-fractional-flow-reserve-based%C3%A2-upon-steady-state-computational-fluid-dynamics-analysis-results-from-the-virtu-fast-study
#4
Paul D Morris, Daniel Alejandro Silva Soto, Jeroen F A Feher, Dan Rafiroiu, Angela Lungu, Susheel Varma, Patricia V Lawford, D Rodney Hose, Julian P Gunn
Fractional flow reserve (FFR)-guided percutaneous intervention is superior to standard assessment but remains underused. The authors have developed a novel "pseudotransient" analysis protocol for computing virtual fractional flow reserve (vFFR) based upon angiographic images and steady-state computational fluid dynamics. This protocol generates vFFR results in 189 s (cf >24 h for transient analysis) using a desktop PC, with <1% error relative to that of full-transient computational fluid dynamics analysis...
August 2017: JACC. Basic to Translational Science
https://www.readbyqxmd.com/read/28905113/influence-of-increased-heart-rate-and-aortic-pressure-on-resting-indices-of-functional-coronary-stenosis-severity
#5
Lorena Casadonte, Bart-Jan Verhoeff, Jan J Piek, Ed VanBavel, Jos A E Spaan, Maria Siebes
Baseline assessment of functional stenosis severity has been proposed as a practical alternative to hyperemic indices. However, intact autoregulation mechanisms may affect intracoronary hemodynamics. The aim of this study was to investigate the effect of changes in aortic pressure (Pa) and heart rate (HR) on baseline coronary hemodynamics and functional stenosis assessment. In 15 patients (55 ± 3% diameter stenosis) Pa, intracoronary pressure (Pd) and flow velocity were obtained at control, and during atrial pacing at 120 bpm, increased Pa (+30 mmHg) with intravenous phenylephrine (PE), and elevated Pa while pacing at sinus heart rate (PE + sHR)...
September 13, 2017: Basic Research in Cardiology
https://www.readbyqxmd.com/read/28851731/exploring-coronary-circulatory-response-to-stenosis-and-its-association-with-invasive-physiologic-indices-using-absolute-myocardial-blood-flow-and-coronary-pressure
#6
Joo Myung Lee, Doyeon Hwang, Jonghanne Park, Jinlong Zhang, Yaliang Tong, Chee Hae Kim, Ji-In Bang, Minseok Suh, Jin Chul Paeng, Gi Jeong Cheon, Bon-Kwon Koo
Background -Although invasive physiologic assessment for coronary stenosis has become a standard practice to guide treatment strategy, coronary circulatory response and changes in invasive physiologic indices, according to different anatomical and hemodynamic lesion severity, have not been fully demonstrated in patients with coronary artery disease. Methods -One hundred fifteen patients with left anterior descending artery stenosis who underwent both (13)N-ammonia positron emission tomography (PET) and invasive physiologic measurement were analyzed...
August 29, 2017: Circulation
https://www.readbyqxmd.com/read/28700893/coronary-microvascular-disease-as-an-early-culprit-in-the-pathophysiology-of-diabetes-and-metabolic-syndrome
#7
REVIEW
Hicham Labazi, Aaron J Trask
Metabolic syndrome (MetS) is a group of cardio-metabolic risk factors that includes obesity, insulin resistance, hypertension, and dyslipidemia; these are also a combination of independent coronary artery disease (CAD) risk factors. Alarmingly, the prevalence of MetS risk factors are increasing and a leading cause for mortality. In the vasculature, complications from MetS and type 2 diabetes (T2D) can be divided into microvascular (retinopathy and nephropathy) and macrovascular (cardiovascular diseases and erectile dysfunction)...
September 2017: Pharmacological Research: the Official Journal of the Italian Pharmacological Society
https://www.readbyqxmd.com/read/28663361/hyperaemic-microvascular-resistance-predicts-clinical-outcome-and-microvascular-injury-after-myocardial-infarction
#8
Guus A de Waard, Gregor Fahrni, Douwe de Wit, Hironori Kitabata, Rupert Williams, Niket Patel, Paul F Teunissen, Peter M van de Ven, Sabahattin Umman, Paul Knaapen, Divaka Perera, Takashi Akasaka, Murat Sezer, Rajesh K Kharbanda, Niels van Royen
OBJECTIVES: Early detection of microvascular dysfunction after acute myocardial infarction (AMI) could identify patients at high risk of adverse clinical outcome, who may benefit from adjunctive treatment. Our objective was to compare invasively measured coronary flow reserve (CFR) and hyperaemic microvascular resistance (HMR) for their predictive power of long-term clinical outcome and cardiac magnetic resonance (CMR)-defined microvascular injury (MVI). METHODS: Simultaneous intracoronary Doppler flow velocity and pressure measurements acquired immediately after revascularisation for AMI from five centres were pooled...
June 29, 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/28653312/link-of-renal-microcirculatory-dysfunction-to-increased-coronary-microcirculatory-resistance-in-hypertensive-patients
#9
Cong Lin, Pu Zhang, Yangjing Xue, Yinqing Huang, Kangting Ji
BACKGROUND: This study investigated the correlation between renal microcirculation and coronary microcirculation in hypertensive patients. METHODS: Participants consisted of 231 consecutive candidates who were referred to the Second Affiliated Hospital of Wenzhou Medical University from March 2014 to May 2016 for elective coronary angiography due to suspected myocardial ischemia. All participants were evaluated for the index of microvascular resistance (IMR), coronary flow reserve (CFR), and fractional flow reserve (FFR) using a pressure wire...
June 27, 2017: Cardiology Journal
https://www.readbyqxmd.com/read/28649956/the-ati-score-age-thrombotic-burden-index-of-microcirculatory-resistance-determined-during-primary-percutaneous-coronary-intervention-predicts-final-infarct-size-in-patients-with-st-elevation-myocardial-infarction-a-cardiac-magnetic-resonance-validation-study
#10
Giovanni Luigi De Maria, Mohammad Alkhalil, Mathias Wolfrum, Gregor Fahrni, Alessandra Borlotti, Lisa Gaughran, Sam Dawkins, Jeremy Langrish, Andrew Lucking, Robin Choudhury, Italo Porto, Filippo Crea, Erica Dall'Armellina, Keith Channon, Rajesh Kharbanda, Adrian Banning
AIMS: The age-thrombus score-index of microcirculatory resistance (ATI) score is a diagnostic tool able to predict suboptimal myocardial reperfusion before stenting, in patients with ST elevation myocardial infarction (STEMI). We aimed to validate the ATI score against cardiac magnetic resonance imaging (cMRI). METHODS AND RESULTS: The ATI score was calculated prospectively in 80 STEMI patients. cMRI was performed within 48 hours in all patients and in 50 patients at six months follow up to assess the extent of infarct size (IS%) and microvascular obstruction (MVO%)...
June 27, 2017: EuroIntervention
https://www.readbyqxmd.com/read/28600102/physiologic-mechanism-of-discordance-between-instantaneous-wave-free-ratio-and-fractional-flow-reserve-insight-from-13-n-ammonium-positron-emission-tomography
#11
Joo Myung Lee, Doyeon Hwang, Jonghanne Park, Yaliang Tong, Bon-Kwon Koo
BACKGROUND: Invasive physiologic indices, such as fractional flow reserve (FFR) or instantaneous wave-free ratio (iFR), are used in clinical practice. We sought to evaluate the physiological mechanism of discordance between iFR and FFR using (13)N-ammonia positron emission tomography (PET)-derived quantitative parameters. METHODS: Data from 113 patients, who underwent both (13)N-ammonia PET and invasive FFR and iFR measurement, were analyzed. Coronary circulatory indices, such as myocardial blood flow (MBF), coronary flow reserve (CFR), microvascular resistance, and trans-stenosis resistance were compared between patients with discordant results (low FFR despite high iFR) and those with concordant abnormal results (low FFR and low iFR), using cut-off values of FFR≤0...
September 15, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/28595700/angiotensin-converting-enzyme-inhibition-early-after-heart-transplantation
#12
RANDOMIZED CONTROLLED TRIAL
William F Fearon, Kozo Okada, Jon A Kobashigawa, Yuhei Kobayashi, Helen Luikart, Sean Sana, Tiffany Daun, Steven A Chmura, Seema Sinha, Garett Cohen, Yasuhiro Honda, Michael Pham, David B Lewis, Daniel Bernstein, Alan C Yeung, Hannah A Valantine, Kiran Khush
BACKGROUND: Cardiac allograft vasculopathy (CAV) remains a leading cause of mortality after heart transplantation (HT). Angiotensin-converting enzyme inhibitors (ACEIs) may retard the development of CAV but have not been well studied after HT. OBJECTIVES: This study tested the safety and efficacy of the ACEI ramipril on the development of CAV early after HT. METHODS: In this prospective, multicenter, randomized, double-blind, placebo-controlled trial, 96 HT recipients were randomized to undergo ramipril or placebo therapy...
June 13, 2017: Journal of the American College of Cardiology
https://www.readbyqxmd.com/read/28577226/pet-measurements-of-myocardial-blood-flow-post-myocardial-infarction-relationship-to-invasive-and-cardiac-magnetic-resonance-studies-and-potential-clinical-applications
#13
Henry Gewirtz
This review focuses on clinical studies concerning assessment of coronary microvascular and conduit vessel function primarily in the context of acute and sub acute myocardial infarction (MI). The ability of quantitative PET measurements of myocardial blood flow (MBF) to delineate underlying pathophysiology and assist in clinical decision making in this setting is discussed. Likewise, considered are physiological metrics fractional flow reserve, coronary flow reserve, index of microvascular resistance (FFR, CFR, IMR) obtained from invasive studies performed in the cardiac catheterization laboratory, typically at the time of PCI for MI...
June 2, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/28576663/impact-of-ranolazine-on-coronary-microvascular-dysfunction-micro-study
#14
Bina Ahmed, Judith Mondragon, Mark Sheldon, Stacey Clegg
BACKGROUND: Patients with angina and coronary microvascular dysfunction, without evidence of structural or epicardial coronary disease (Type I CMVD) remain without evidence based treatment options. Previous work has demonstrated that ranolazine can improve angina frequency and stability among patients with Type 1 CMVD; however, the mechanism remains unclear. Therefore, the objective of this pilot project was to assess the impact of ranolazine on Type I CMVD as measured using an invasive tool to measure global resistance (index of microcirculatory resistance (IMR))...
September 2017: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/28566295/significance-of-microvascular-function-in-visual-functional-mismatch-between-invasive-coronary-angiography-and-fractional-flow-reserve
#15
Taishi Yonetsu, Tadashi Murai, Yoshihisa Kanaji, Tetsumin Lee, Junji Matsuda, Eisuke Usui, Masahiro Hoshino, Makoto Araki, Takayuki Niida, Masahiro Hada, Sadamitsu Ichijo, Rikuta Hamaya, Yoshinori Kanno, Tsunekazu Kakuta
BACKGROUND: Despite a moderate correlation between angiographical stenosis and physiological significance, the mechanism of discordance has not been fully elucidated, particularly regarding the significance of microvascular function. This study sought to clarify whether microvascular function affects visual-functional mismatch between quantitative coronary angiography (QCA) and fractional flow reserve (FFR). METHODS AND RESULTS: We assessed QCA, FFR, coronary flow reserve, and the index of microcirculatory resistance in 849 non-left-main coronary lesions with visually estimated intermediate stenoses from 532 patients...
May 31, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/28550173/experimental-cardiac-radiation-exposure-induces-ventricular-diastolic-dysfunction-with-preserved-ejection-fraction
#16
Hirofumi Saiki, Gilles Moulay, Adam J Guenzel, Weibin Liu, Teresa D Decklever, Kelly L Classic, Linh Pham, Horng H Chen, John C Burnett, Stephen J Russell, Margaret M Redfield
Breast cancer radiotherapy increases the risk of heart failure with preserved ejection fraction (HFpEF). Cardiomyocytes are highly radioresistant, but radiation specifically affects coronary microvascular endothelial cells, with subsequent microvascular inflammation and rarefaction. The effects of radiation on left ventricular (LV) diastolic function are poorly characterized. We hypothesized that cardiac radiation exposure may result in diastolic dysfunction without reduced EF. Global cardiac expression of the sodium-iodide symporter (NIS) was induced by cardiotropic gene (adeno-associated virus serotype 9) delivery to 5-wk-old rats...
August 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/28526024/protective-effect-on-the-coronary-microcirculation-of-patients-with-diabetes-by-clopidogrel-or-ticagrelor-predict-study-rationale-and-design-a-randomized-multicenter-clinical-trial-using-intracoronary-multimodal-physiology
#17
Enrico Cerrato, Alicia Quirós, Mauro Echavarría-Pinto, Hernan Mejia-Renteria, Andres Aldazabal, Nicola Ryan, Nieves Gonzalo, Pilar Jimenez-Quevedo, Luis Nombela-Franco, Pablo Salinas, Iván J Núñez-Gil, José Ramón Rumoroso, Antonio Fernández-Ortiz, Carlos Macaya, Javier Escaned
BACKGROUND: In diabetic patients a predisposed coronary microcirculation along with a higher risk of distal particulate embolization during primary percutaneous intervention (PCI) increases the risk of peri-procedural microcirculatory damage. However, new antiplatelet agents, in particular Ticagrelor, may protect the microcirculation through its adenosine-mediated vasodilatory effects. METHODS: PREDICT is an original, prospective, randomized, multicenter controlled study designed to investigate the protective effect of Ticagrelor on the microcirculation during PCI in patient with diabetes mellitus type 2 or pre-diabetic status...
May 19, 2017: Cardiovascular Diabetology
https://www.readbyqxmd.com/read/28521932/discordance-between-fractional-flow-reserve-and-coronary-flow-reserve-insights-from-intracoronary-imaging-and-physiological%C3%A2-assessment
#18
Sung Gyun Ahn, Jon Suh, Olivia Y Hung, Hee Su Lee, Yasir H Bouchi, Wenjie Zeng, Rounak Gandhi, Parham Eshtehardi, Bill D Gogas, Habib Samady
OBJECTIVES: The aim of this study was to investigate the epicardial and microvascular substrates associated with discordances between fractional flow reserve (FFR) and coronary flow reserve (CFR) values. BACKGROUND: Discordances between FFR and CFR remain poorly characterized. METHODS: FFR, hyperemic stenosis resistance (HSR), and intravascular ultrasound were performed as indexes of epicardial function and CFR and hyperemic microvascular resistance (HMR) as measures of microvascular function in 94 patients with moderate coronary stenosis...
May 22, 2017: JACC. Cardiovascular Interventions
https://www.readbyqxmd.com/read/28514327/postoperative-assessment-of-myocardial-function-and-microcirculation-in-patients-with-acute-coronary-syndrome-by-myocardial-contrast-echocardiography
#19
Li Jiang, Hong Yao, Zhao-Guang Liang
BACKGROUND Postoperative myocardial function and microcirculation of acute coronary syndrome (ACS) was assessed by myocardial contrast echocardiography (MCE). MATERIAL AND METHODS Eighty-nine ACS patients treated with percutaneous coronary intervention (PCI) were detected by MCE and two-dimensional ultrasonography before and a month later after PCI respectively. Their myocardial perfusion was evaluated by myocardial contrast score (MSC) and contrast score index (CSI); cross-sectional area of microvessel (A), average myocardial microvascular impairment (β), and myocardial blood flow (MBF) were analyzed by cardiac ultrasound quantitative analysis (CUSQ), and fractional flow reserve (FFR) change was observed...
May 17, 2017: Medical Science Monitor: International Medical Journal of Experimental and Clinical Research
https://www.readbyqxmd.com/read/28506937/bivalirudin-infusion-to-reduce-ventricular-infarction-the-open-label-randomised-bivalirudin-infusion-for-ventricular-infarction-limitation-bival-study
#20
Robert Jan van Geuns, Georgios Sideris, Niels Van Royen, Rami El Mahmoud, Roberto Diletti, Claire Bal Dit Sollier, Jerome Garot, Nina W Van Der Hoeven, Bernardo Cortese, Li Ding, Ilknur Lechthaler, Efthymios N Deliargyris, Prodromos Anthopoulos, Ludovic Drouet
AIMS: The aim of the study was to investigate whether bivalirudin versus unfractionated heparin (UFH) reduces infarct size (IS) for primary percutaneous coronary intervention (PPCI) in large acute myocardial infarction (AMI). METHODS AND RESULTS: This multicentre open-label trial randomised 78 patients undergoing PPCI for large AMI to bivalirudin or UFH. The primary endpoint was IS, assessed by cardiac magnetic resonance (CMR) five days after PPCI. Secondary endpoints included index of microcirculatory resistance (IMR), CMR-assessed microvascular obstruction (MVO) and ejection fraction, and biomarkers for thrombin activity and cell injury...
August 4, 2017: EuroIntervention
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