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coronary microvascular resistance

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https://www.readbyqxmd.com/read/29222132/invasive-assessment-of-the-coronary-microvasculature-the-index-of-microcirculatory-resistance
#1
REVIEW
William F Fearon, Yuhei Kobayashi
Traditionally, invasive coronary physiological assessment has focused on the epicardial coronary artery. More recently, appreciation of the importance of the coronary microvasculature in determining patient outcomes has grown. Several invasive modalities for interrogating microvascular function have been proposed. Angiographic techniques have been limited by their qualitative and subjective nature. Doppler wire-derived coronary flow reserve has been applied in research studies, but its clinical role has been limited by its lack of reproducibility, its lack of a clear normal value, and the fact that it is not specific for the microvasculature but interrogates the entire coronary circulation...
December 2017: Circulation. Cardiovascular Interventions
https://www.readbyqxmd.com/read/29215470/invasive-assessment-of-microvascular-function-in-patients-with-valvular-heart-disease
#2
Takeshi Nishi, Hideki Kitahara, Saito Yuichi, Tomoko Nishi, Takashi Nakayama, Yoshihide Fujimoto, Goro Matsumiya, Yoshio Kobayashi
BACKGROUND: The aim of this study was to investigate microvascular function in patients with valvular heart disease (VHD), which causes chronic left ventricular volume and/or pressure overload, therefore change in coronary microvascular hemodynamics. PATIENTS AND METHODS: We prospectively enrolled 30 patients with VHD considered for surgery (10 aortic stenosis, 12 aortic regurgitation, and eight mitral regurgitation) and 30 controls. Intracoronary physiological assessments were performed in the unobstructed left anterior descending artery using a pressure-temperature sensor guidewire at rest and hyperemia...
December 5, 2017: Coronary Artery Disease
https://www.readbyqxmd.com/read/29209950/spect-myocardial-ischemia-in-the-absence-of-obstructive-cad-contribution-of-the-invasive-assessment-of-microvascular-dysfunction
#3
Loïc Djaïleb, Laurent Riou, Nicolas Piliero, Adrien Carabelli, Estelle Vautrin, Alexis Broisat, Julien Leenhardt, Jacques Machecourt, Daniel Fagret, Gerald Vanzetto, Gilles Barone-Rochette, Catherine Ghezzi
Coronary microvascular dysfunction has recently emerged as a major independent prognostic factor and can be invasively assessed by coronary flow reserve (CFR) and the index of microvascular resistance (IMR). The incremental prognostic value of myocardial ischemia from SPECT myocardial perfusion imaging (MPI) over clinical characteristics, cardiac risk factors, and stress test data for the prediction of hard cardiac events (myocardial infarction and cardiac death) has been well demonstrated over the last two decades regardless of the absence or presence of epicardial CAD...
December 5, 2017: Journal of Nuclear Cardiology: Official Publication of the American Society of Nuclear Cardiology
https://www.readbyqxmd.com/read/29196345/mitoprotection-attenuates-myocardial-vascular-impairment-in-porcine-metabolic-syndrome
#4
Fang Yuan, Ahmad F Hedayat, Christopher M Ferguson, Amir Lerman, Lilach O Lerman, Alfonso Eirin
INTRODUCTION: The metabolic syndrome (MetS) leads to cardiac vascular injury, which may reflect in increased retention of endothelial progenitor cells (EPC). Coronary endothelial cell (EC) mitochondria partly regulate vascular function and structure. We hypothesized that chronic mitoprotection would preserve EC mitochondria and attenuate coronary vascular injury and dysfunction in swine MetS. METHODS: Pigs were studied after 16 weeks of diet-induced MetS, MetS treated for the last 4 weeks with the mitochondria-targeted peptide elamipretide (ELAM, 0...
December 1, 2017: American Journal of Physiology. Heart and Circulatory Physiology
https://www.readbyqxmd.com/read/29192067/effect-of-myostatin-deletion-on-cardiac-and-microvascular-function
#5
Joshua T Butcher, M Irfan Ali, Merry W Ma, Cameron G McCarthy, Bianca N Islam, Lauren G Fox, James D Mintz, Sebastian Larion, David J Fulton, David W Stepp
The objective of this study is to test the hypothesis that increased muscle mass has positive effects on cardiovascular function. Specifically, we tested the hypothesis that increases in lean body mass caused by deletion of myostatin improves cardiac performance and vascular function. Echocardiography was used to quantify left ventricular function at baseline and after acute administration of propranolol and isoproterenol to assess β-adrenergic reactivity. Additionally, resistance vessels in several beds were removed, cannulated, pressurized to 60 mmHg and reactivity to vasoactive stimuli was assessed...
December 2017: Physiological Reports
https://www.readbyqxmd.com/read/29169759/abnormal-coronary-vasoreactivity-in-transient-left-ventricular-apical-ballooning-tako-tsubo-syndrome
#6
Edoardo Verna, Stefano Provasoli, Sergio Ghiringhelli, Fabrizio Morandi, Jorge Salerno-Uriarte
BACKGROUND: The exact etiology and pathophysiologic mechanisms of tako-tsubo syndrome (TTS) remain controversial. OBJECTIVE: To further evaluate the abnormal coronary vasoreactivity and its possible anatomical substrate in TTS. METHODS: We studied 47 patients (46 women; age 67±12years) who underwent diagnostic cardiac catheterization and evaluation of coronary vasoreactivity by sequential acetylcholine (Ach), nitroglycerine and adenosine testing with angiographic and intracoronary pressure-Doppler flow monitoring...
January 1, 2018: International Journal of Cardiology
https://www.readbyqxmd.com/read/29154426/microvascular-dysfunction-and-cardiac-fibrosis-in-heart-failure-with-preserved-ejection-fraction-a-case-report
#7
Nikhil Narang, Diego Medvedofsky, Kathryn Dryer, Sanjiv J Shah, Charles J Davidson, Amit R Patel, John E A Blair
We report the case of a 55-year-old woman with heart failure with preserved ejection fraction (HFpEF), who presented with hypertensive urgency and pulmonary oedema. The patient was medically optimized and underwent cardiac catheterization revealing pulmonary hypertension, elevated pulmonary capillary wedge pressure, normal cardiac index, and non-obstructive coronary disease. Invasive evaluation of coronary flow revealed blunted coronary flow reserve and increased index of microvascular resistance. Cardiac magnetic resonance imaging demonstrated reduced global myocardial perfusion and diffuse interstitial fibrosis...
November 2017: ESC Heart Failure
https://www.readbyqxmd.com/read/29146670/three-vessel-assessment-of-coronary-microvascular-dysfunction-in-patients-with-clinical-suspicion-of-ischemia-prospective-observational-study-with-the-index-of-microcirculatory-resistance
#8
Yuhei Kobayashi, Joo Myung Lee, William F Fearon, Jang Hoon Lee, Takeshi Nishi, Dong-Hyun Choi, Frederik M Zimmermann, Ji-Hyun Jung, Hyun-Jung Lee, Joon-Hyung Doh, Chang-Wook Nam, Eun-Seok Shin, Bon-Kwon Koo
BACKGROUND: Difficulty directly visualizing the coronary microvasculature as opposed to the epicardial coronary artery makes its assessment challenging. The goal of this study is to measure the index of microcirculatory resistance (IMR) in all 3 major coronary vessels to identify the clinical and angiographic predictors of an abnormal IMR. METHODS AND RESULTS: Ninety-three patients who underwent coronary physiological assessment in all 3 major coronary vessels were prospectively enrolled (59...
November 2017: Circulation. Cardiovascular Interventions
https://www.readbyqxmd.com/read/29132649/doppler-versus-thermodilution-derived-coronary-microvascular-resistance-to-predict-coronary-microvascular-dysfunction-in-patients-with-acute-myocardial-infarction-or-stable-angina-pectoris
#9
Rupert P Williams, Guus A de Waard, Kalpa De Silva, Matthew Lumley, Kaleab Asrress, Satpal Arri, Howard Ellis, Awais Mir, Brian Clapp, Amedeo Chiribiri, Sven Plein, Paul F Teunissen, Maurits R Hollander, Michael Marber, Simon Redwood, Niels van Royen, Divaka Perera
Coronary microvascular resistance is increasingly measured as a predictor of clinical outcomes, but there is no accepted gold-standard measurement. We compared the diagnostic accuracy of 2 invasive indices of microvascular resistance, Doppler-derived hyperemic microvascular resistance (hMR) and thermodilution-derived index of microcirculatory resistance (IMR), at predicting microvascular dysfunction. A total of 54 patients (61 ± 10 years) who underwent cardiac catheterization for stable coronary artery disease (n = 10) or acute myocardial infarction (n = 44) had simultaneous intracoronary pressure, Doppler flow velocity and thermodilution flow data acquired from 74 unobstructed vessels, at rest and during hyperemia...
October 10, 2017: American Journal of Cardiology
https://www.readbyqxmd.com/read/29113999/index-of-microcirculatory-resistance-at-the-time-of-primary-percutaneous-coronary-intervention-predicts-early-cardiac-complications-insights-from-the-oxami-oxford-study-in-acute-myocardial-infarction-cohort
#10
Gregor Fahrni, Mathias Wolfrum, Giovanni Luigi De Maria, Florim Cuculi, Sam Dawkins, Mohammad Alkhalil, Niket Patel, John C Forfar, Bernard D Prendergast, Robin P Choudhury, Keith M Channon, Adrian P Banning, Rajesh K Kharbanda
BACKGROUND: Early risk stratification after primary percutaneous coronary intervention (PPCI) for ST-segment-elevation myocardial infarction is currently challenging. Identification of a low-risk group may improve triage of patients to alternative clinical pathways and support early hospital discharge. Our aim was to assess whether the index of microcirculatory resistance (IMR) at the time of PPCI can identify patients at low risk of early major cardiac complications and to compare its performance against guideline-recommended risk scores...
November 7, 2017: Journal of the American Heart Association
https://www.readbyqxmd.com/read/29095792/important-role-of-endothelial-caveolin-1-in-the-protective-role-of-edh-against-no-mediated-nitrative-stress-in-microcirculation-in-mice
#11
Hiroki Saito, Shigeo Godo, Saori Sato, Akiyo Ito, Yosuke Ikumi, Shuhei Tanaka, Tomoaki Ida, Shigemoto Fujii, Takaaki Akaike, Hiroaki Shimokawa
AIMS: Nitric oxide (NO) and endothelium-dependent hyperpolarization (EDH) play important roles in maintaining cardiovascular homeostasis. We have previously demonstrated that endothelial NO synthase (eNOS) plays diverse roles depending on vessel size, as a NO generating system in conduit arteries and an EDH-mediated system in resistance arteries, for which caveolin-1(Cav-1) is involved. However, the physiological role of endothelial Cav-1 in microvessels remains to be elucidated. METHODS AND RESULTS: We newly generated endothelium-specific Cav-1-knockout (eCav-1-KO) mice...
October 27, 2017: Journal of Cardiovascular Pharmacology
https://www.readbyqxmd.com/read/29069202/association-of-inflammation-and-endothelial-dysfunction-with-coronary-microvascular-resistance-in-patients-with-cardiac-syndrome-x
#12
Ming Long, Zhibin Huang, Xiaodong Zhuang, Zena Huang, Yue Guo, Xinxue Liao, Chufan Luo
BACKGROUND: Although a proportion of CSX patients have impaired brachial artery flow-mediated dilatation (FMD) in response to hyperemia, suggesting that endothelial dysfunction in these patients may be systemic and not just confined to the coronary circulation; the underlying mechanisms triggering endothelial dysfunction in these patients are still incompletely understood. OBJECTIVES: To assess the association of the index of Microcirculatory Resistance (IMR) with endothelial dysfunction and inflammation in patients with CSX...
October 19, 2017: Arquivos Brasileiros de Cardiologia
https://www.readbyqxmd.com/read/29042091/effects-of-renal-denervation-on-coronary-flow-reserve-and-forearm-dilation-capacity-in-patients-with-treatment-resistant-hypertension-a-randomized-double-blinded-sham-controlled-clinical-trial
#13
Morten Engholm, Jannik B Bertelsen, Ole N Mathiassen, Hans E Bøtker, Henrik Vase, Christian D Peters, Jesper N Bech, Niels H Buus, Anne P Schroeder, Hans Rickers, Klavs W Hansen, Per L Poulsen, Anne Kaltoft, Kent L Christensen
BACKGROUND: Microvascular impairment is well documented in hypertension. We investigated the effect of renal sympathetic denervation (RDN) on cardiac and peripheral microvasculature in patients with treatment-resistant essential hypertension (TRH). METHODS: A randomized, single centre, double-blinded, sham-controlled clinical trial. Fifty-eight patients with TRH (ambulatory systolic BP (ASBP) ≥ 145mmHg) despite stable treatment were randomized to RDN or SHAM. RDN was performed with the unipolar Medtronic Flex catheter...
October 1, 2017: International Journal of Cardiology
https://www.readbyqxmd.com/read/29038227/quantification-of-absolute-coronary-blood-flow-and-microvascular-resistance
#14
EDITORIAL
Brahim Harbaoui, Olivier Muller
No abstract text is available yet for this article.
October 2017: Circulation. Cardiovascular Interventions
https://www.readbyqxmd.com/read/29038224/effect-of-elective-percutaneous-coronary-intervention-on-hyperemic-absolute-coronary-blood-flow-volume-and-microvascular-resistance
#15
Yoshihisa Kanaji, Tadashi Murai, Taishi Yonetsu, Eisuke Usui, Makoto Araki, Junji Matsuda, Masahiro Hoshino, Masao Yamaguchi, Takayuki Niida, Masahiro Hada, Sadamitsu Ichijyo, Rikuta Hamaya, Yoshinori Kanno, Mitsuaki Isobe, Tsunekazu Kakuta
BACKGROUND: The hemodynamics involved in the relationship between absolute coronary blood flow (ABF) volume and myocardial resistance (MR) are complex, and the effect of percutaneous coronary intervention (PCI) on their changes remains unclear. The aim of this study was to investigate the differences in hyperemic ABF and MR before and after elective PCI using a thermodilution method. METHODS AND RESULTS: We investigated 28 vessels (right coronary artery, 9; left anterior descending coronary artery, 18; left circumflex coronary artery, 1) from 28 patients with stable angina pectoris undergoing elective PCI...
October 2017: Circulation. Cardiovascular Interventions
https://www.readbyqxmd.com/read/29037762/evaluation-of-lesion-flow-coefficient-for-the-detection-of-coronary-artery-disease-in-patient-groups-from-two-academic-medical-centers
#16
Srikara V Peelukhana, Rupak K Banerjee, Tim P van de Hoef, Kranthi K Kolli, Mohamed Effat, Tarek Helmy, Massoud Leesar, Hanan Kerr, Jan J Piek, Paul Succop, Lloyd Back, Imran Arif
BACKGROUND: In this study, lesion flow coefficient (LFC: ratio of % area stenosis [%AS] to the square root of the ratio of the pressure drop across the stenosis to the dynamic pressure in the throat region), that combines both the anatomical (%AS) and functional measurements (pressure and flow), was assessed for application in a clinical setting. METHODS AND RESULTS: Pressure, flow, and anatomical values were obtained from patients in 251 vessels from two different centers...
September 11, 2017: Cardiovascular Revascularization Medicine: Including Molecular Interventions
https://www.readbyqxmd.com/read/29030424/stable-coronary-syndromes-pathophysiology-diagnostic-advances-and-therapeutic-need
#17
REVIEW
Thomas J Ford, David Corcoran, Colin Berry
The diagnostic management of patients with angina pectoris typically centres on the detection of obstructive epicardial CAD, which aligns with evidence-based treatment options that include medical therapy and myocardial revascularisation. This clinical paradigm fails to account for the considerable proportion (approximately one-third) of patients with angina in whom obstructive CAD is excluded. This common scenario presents a diagnostic conundrum whereby angina occurs but there is no obstructive CAD (ischaemia and no obstructive coronary artery disease-INOCA)...
October 13, 2017: Heart: Official Journal of the British Cardiac Society
https://www.readbyqxmd.com/read/29025901/effects-of-age-and-exercise-training-on-coronary-microvascular-smooth-muscle-phenotype-and-function
#18
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
#19
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
#20
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
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