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- Danad, Ibrahim, et al.
(author)
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Quantitative Assessment of Myocardial Perfusion in the Detection of Significant Coronary Artery Disease Cutoff Values and Diagnostic Accuracy of Quantitative [O-15]H2O PET Imaging
- 2014
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In: Journal of the American College of Cardiology. - : Elsevier BV. - 0735-1097 .- 1558-3597. ; 64:14, s. 1464-1475
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Journal article (peer-reviewed)abstract
- BACKGROUND Recent studies have demonstrated improved diagnostic accuracy for detecting coronary artery disease (CAD) when myocardial blood flow (MBF) is quantified in absolute terms, but there are no uniformly accepted cutoff values for hemodynamically significant CAD. OBJECTIVES The goal of this study was to determine cutoff values for absolute MBF and to evaluate the diagnostic accuracy of quantitative [O-15]H2O positron emission tomography (PET). METHODS A total of 330 patients underwent both quantitative [O-15]H2O PET imaging and invasive coronary angiography in conjunction with fractional flow reserve measurements. A stenosis >90% and/or fractional flow reserve <= 0.80 was considered obstructive; a stenosis <30% and/or fractional flow reserve >0.80 was nonobstructive. RESULTS Hemodynamically significant CAD was diagnosed in 116 (41%) of 281 patients who fulfilled study criteria for CAD. Resting perfusion was 1.00 +/- 0.25 and 0.92 +/- 0.23 ml/min/g in regions supplied by nonstenotic and significantly stenosed vessels, respectively (p < 0.001). During stress, perfusion increased to 3.26 +/- 1.04 ml/min/g and 1.73 +/- 0.67 ml/min/g, respectively (p < 0.001). The optimal cutoff values were 2.3 and 2.5 for hyperemic MBF and myocardial flow reserve, respectively. For MBF, these cutoff values showed a sensitivity, specificity, and accuracy for detecting significant CAD of 89%, 84%, and 86%, respectively, at a per-patient level and 87%, 85%, and 85% at a per-vessel level. The corresponding myocardial flow reserve values were 86%, 72%, and 78% (per patient) and 80%, 82%, and 81% (per vessel). Age and sex significantly affected diagnostic accuracy of quantitative PET. CONCLUSIONS Quantitative MBF measurements with the use of [O-15]H2O PET provided high diagnostic performance, but both sex and age should be taken into account.
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- Kolh, P, et al.
(author)
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Guidelines on myocardial revascularization
- 2010
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In: European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery. - : Oxford University Press (OUP). - 1873-734X .- 1010-7940. ; 3838 Suppl, s. S1-S52
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Journal article (peer-reviewed)
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- Laaksonen, Marko, 1975-, et al.
(author)
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Perfusion heterogeneity does not explain excess muscle oxygen uptake during variable intensity exercise
- 2010
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In: Clinical Physiology and Functional Imaging. - 1475-0961 .- 1475-097X. ; 30:4, s. 241-249
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Journal article (peer-reviewed)abstract
- The association between muscle oxygen uptake (VO2) and perfusion or perfusion heterogeneity (relative dispersion, RD) was studied in eight healthy male subjects during intermittent isometric (1 s on, 2 s off) one-legged knee-extension exercise at variable intensities using positron emission tomography and a-v blood sampling. Resistance during the first 6 min of exercise was 50% of maximal isometric voluntary contraction force (MVC) (HI-1), followed by 6 min at 10% MVC (LOW) and finishing with 6 min at 50% MVC (HI-2). Muscle perfusion and O2 delivery during HI-1 (26 ± 5 and 5·4 ± 1·0 ml 100 g−1 min−1) and HI-2 (28 ± 4 and 5·8 ± 0·7 ml 100 g−1 min−1) were similar, but both were higher (P<0·01) than during LOW (15 ± 3 and 3·0 ± 0·6 ml 100 g−1 min−1). Muscle VO2 was also higher during both HI workloads (HI-1 3·3 ± 0·4 and HI-2 4·1 ± 0·6 ml 100 g−1 min−1) than LOW (1·4 ± 0·4 ml 100 g−1 min−1; P<0·01) and 25% higher during HI-2 than HI-1 (P<0·05). O2 extraction was higher during HI workloads (HI-1 62 ± 7 and HI-2 70 ± 7%) than LOW (45 ± 8%; P<0·01). O2 extraction tended to be higher (P = 0·08) during HI-2 when compared to HI-1. Perfusion was less heterogeneous (P<0·05) during HI workloads when compared to LOW with no difference between HI workloads. Thus, during one-legged knee-extension exercise at variable intensities, skeletal muscle perfusion and O2 delivery are unchanged between high-intensity workloads, whereas muscle VO2 is increased during the second high-intensity workload. Perfusion heterogeneity cannot explain this discrepancy between O2 delivery and uptake. We propose that the excess muscle VO2 during the second high-intensity workload is derived from working muscle cells.
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| 9. |
- Laaksonen, Marko, et al.
(author)
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Regional differences in blood flow, glucose uptake and fatty acid uptake within quadriceps femoris muscle during dynamic knee-extension exercise
- 2013
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In: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6319 .- 1439-6327. ; 113:7, s. 1775-1782
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Journal article (peer-reviewed)abstract
- The purpose of the present study was to investigate the regional differences in glucose and fatty acid uptake within skeletal muscle during exercise. Blood flow (BF), glucose uptake (GU) and free fatty acid uptake (FFAU) were measured in four different regions (vastus lateralis, VL; rectus femoris, RF; vastus intermedius, VI; and vastus medialis, VM) of the quadriceps femoris (QF) muscle during low-intensity, knee-extension exercise using positron emission tomography. BF was higher in VI than in VL, RF and VM (P < 0.05). FFAU was higher in VI (P < 0.001) but also in VM (P < 0.05) compared with VL and RF. In contrast, GU was higher in RF compared with VL (P < 0.05) but was not significantly different to VM or VI (both P = NS). FFAU within these four muscle regions correlated significantly with BF (r = 0.951, P < 0.05), whereas no significant relationship was observed between GU and BF (r = 0.352, P = NS). Therefore, skeletal muscle FFAU, but not GU, appears to be associated with BF during low-intensity exercise. The present results also indicate considerable regional differences in substrate use within working QF muscle. As such, an important methodological outcome from these results is that one sample from a specific part of the QF muscle does not represent the response in the entire QF muscle group.
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- Laaksonen, Marko S, 1975-, et al.
(author)
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VO2peak, myocardial hypertrophy, and myocardial blood flow in endurance-trained men
- 2014
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In: Medicine and science in sports and exercise. - 1530-0315. ; 46:8, s. 1498-1505
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Endurance training induces cardiovascular and metabolic adaptations, leading to enhanced endurance capacity and exercise performance. Previous human studies have shown contradictory results in functional myocardial vascular adaptations to exercise training, and we hypothesized that this may be related to different degrees of hypertrophy in the trained heart. METHODS: We studied the interrelationships between peak aerobic power (V̇O2peak), myocardial blood flow (MBF) at rest and during adenosine-induced vasodilation, and parameters of myocardial hypertrophy in endurance-trained (ET, n = 31) and untrained (n = 17) subjects. MBF and myocardial hypertrophy were studied using positron emission tomography and echocardiography, respectively. RESULTS: Both V̇O2peak (P < 0.001) and left ventricular (LV) mass index (P < 0.001) were higher in the ET group. Basal MBF was similar between the groups. MBF during adenosine was significantly lower in the ET group (2.88 ± 1.01 vs 3.64 ± 1.11 mLg-1min-1, P < 0.05) but not when the difference in LV mass was taken into account. V̇O2peak correlated negatively with adenosine-stimulated MBF, but when LV mass was taken into account as a partial correlate, this correlation disappeared. CONCLUSIONS: The present results show that increased LV mass in ET subjects explains the reduced hyperemic myocardial perfusion in this subject population and suggests that excessive LV hypertrophy has negative effect on cardiac blood flow capacity.
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- Rissanen, Tuomas T., et al.
(author)
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The bottleneck stent model for chronic myocardial ischemia and heart failure in pigs
- 2013
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In: American Journal of Physiology. Heart and Circulatory Physiology. - : American Physiological Society. - 0363-6135 .- 1522-1539. ; 305:9, s. H1297-H1308
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Journal article (peer-reviewed)abstract
- A large animal model of chronic myocardial ischemia and heart failure is crucial for the development of novel therapeutic approaches. In this study we developed a novel percutaneous one-and two-vessel model for chronic myocardial ischemia using a stent coated with a polytetrafluoroethylene tube formed in a bottleneck shape. The bottleneck stent was implanted in the proximal left anterior descending (LAD) or proximal circumflex artery (LCX), or in both proximal LCX and mid LAD 1 wk later (2-vessel model), and pigs were followed for 4-5 wk. Ejection fraction (EF), infarct size, collateral growth, and myocardial perfusion were assessed. Pigs were given antiarrhythmic medication to prevent sudden death. The occlusion time of the bottleneck stent and the timing of myocardial infarction could be modulated by the duration of antiplatelet medication. Fractional flow reserve measurements and positron emission tomography imaging showed severe ischemia after bottleneck stenting covering over 50% of the left ventricle in the proximal LAD model. Complete coronary occlusion was necessary for significant collateral growth, which mostly had occurred already during the first wk after the stent occlusion. Dynamic and competitive collateral growth patterns were observed. EF declined from 64 to 41% in the LCX model and to 44% in the LAD model 4 wk after stenting with 12 and 21% infarcted left ventricle in the LCX and LAD models, respectively. The mortality was 32 and 37% in the LCX and LAD models but very (71%) high in the two-vessel disease model. The implantation of a novel bottleneck stent in the proximal LAD or LCX is a novel porcine model of reversible myocardial ischemia (open stent) and ischemic heart failure (occluded stent) and is feasible for the development of new therapeutic approaches.
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| 18. |
- Rydén, Lars, et al.
(author)
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ESC Guidelines on diabetes, pre-diabetes, and cardiovascular diseases developed in collaboration with the EASD
- 2013
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In: European Heart Journal. - : Oxford University Press (OUP). - 0195-668X .- 1522-9645. ; 34:39, s. 3035-3087
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Journal article (peer-reviewed)abstract
- This is the second iteration of the European Society of Cardiology (ESC) and European Association for the Study of Diabetes (EASD) joining forces to write guidelines on the management of diabetes mellitus (DM), pre-diabetes, and cardiovascular disease (CVD), designed to assist clinicians and other healthcare workers to make evidence-based management decisions. The growing awareness of the strong biological relationship between DM and CVD rightly prompted these two large organizations to collaborate to generate guidelines relevant to their joint interests, the first of which were published in 2007. Some assert that too many guidelines are being produced but, in this burgeoning field, five years in the development of both basic and clinical science is a long time and major trials have reported in this period, making it necessary to update the previous Guidelines.
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| 27. |
- Wijns, W, et al.
(author)
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Myocardial revascularization
- 2011
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In: REVISTA PORTUGUESA DE CARDIOLOGIA. - : Elsevier BV. - 0870-2551 .- 2174-2049. ; 30:12, s. 951-1005
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Journal article (other academic/artistic)
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