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Ruel M, Beanlands RS, Lortie M, Chan V, Camack N, deKemp RA, Suuronen EJ, Rubens FD, DaSilva JN, Sellke FW, Stewart DJ, Mesana TG. Concomitant treatment with oral L-arginine improves the efficacy of surgical angiogenesis in patients with severe diffuse coronary artery disease: the Endothelial Modulation in Angiogenic Therapy randomized controlled trial. J Thorac Cardiovasc Surg 2008; 135:762-70, 770.e1. [PMID: 18374753 DOI: 10.1016/j.jtcvs.2007.09.073] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/04/2007] [Revised: 09/16/2007] [Accepted: 09/25/2007] [Indexed: 02/05/2023]
Abstract
OBJECTIVE Endothelial dysfunction and decreased nitric oxide bioavailability may explain why therapeutic angiogenesis and cell therapy have mostly failed in humans. Building from previous large animal work, the Phase I Endothelial Modulation in Angiogenic Therapy trial tested the hypothesis that L-arginine, a nitric oxide donor, may be safe and effective in potentiating surgical angiogenesis in humans. METHODS Patients with surgical triple-vessel coronary disease and a severely diffusely diseased left anterior descending artery were randomized in 2 x 2 factorial fashion to receive ten 200-microg injections of vascular endothelial growth factor-165 plasmid DNA or placebo in the anterior myocardium along the proximal and mid-left anterior descending arteries, plus oral L-arginine supplementation at a dose of 6 g per day or placebo for 3 months. The distal left anterior descending artery and other coronary arteries were grafted. End points included 3-month changes in myocardial perfusion and contractility of the anterior myocardium, using (13)N-ammonia positron emission tomography and echocardiography. Baseline scans were obtained 3 to 7 days postoperatively to delineate treatment effects from the effects of coronary artery bypass grafting. RESULTS Patient (N = 19) characteristics were equivalent between groups. There was no perioperative or late mortality. Patients who received the combination of vascular endothelial growth factor and L-arginine had improved anterior wall perfusion on positron emission tomography (P = .02), a trend toward smaller perfusion defects (P = .10), and better anterior wall contractility (P = .02, Kruskal-Wallis) at 3 months versus baseline. This was corroborated by a trend toward better disease perception at 3 months versus baseline on the Seattle Angina Questionnaire (score improvement of 47 +/- 35, combination treatment group; P = .1, Kruskal-Wallis). CONCLUSION To our knowledge, this is the first study to examine concomitant substrate modification in patients undergoing new biosurgical therapies by using vascular endothelial growth factor angiogenesis. The results suggest safety and efficacy. Concomitant endothelial modulation with L-arginine not only has the potential to make angiogenesis effective but also may have implications for cell therapy trials.
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Affiliation(s)
- Marc Ruel
- Division of Cardiac Surgery, University of Ottawa, Ottawa, Ontario, Canada.
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Chen GP, Branch KR, Alessio AM, Pham P, Tabibiazar R, Kinahan P, Caldwell JH. Effect of reconstruction algorithms on myocardial blood flow measurement with 13N-ammonia PET. J Nucl Med 2007; 48:1259-65. [PMID: 17631543 PMCID: PMC2586832 DOI: 10.2967/jnumed.106.038232] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED Filtered backprojection (FBP) is the traditional method for 13N-NH3 PET studies. Ordered-subsets expectation maximization (OSEM) is popular for PET studies because of better noise properties. Scant data exist on the effect of reconstruction algorithms on quantitative myocardial blood flow (MBF) estimation. METHODS Twenty patients underwent dynamic acquisition rest/stress 13N-NH3 studies. In Part 1, 19 rest/stress image pairs were reconstructed by FBP (10-mm Hanning filter) and by OSEM with 28 subsets and 2 (OSEM2), 6 (OSEM6), or 8 iterations (OSEM8), and a 10-mm postreconstruction smoothing gaussian filter. In Part 2, 9 image pairs were reconstructed by FBP (10-mm Hanning filter) and by OSEM with 28 subsets, 8 iterations, and a gaussian 5-, 10-, or 15-mm postreconstruction smoothing filter. Average MBF (mL/min/mL of myocardium) was calculated using a 3-compartment model. RESULTS Part 1: For rest MBF, the correlations between FBP and each of the OSEM algorithms were r2 = 0.71, 0.73, and 0.77, respectively. MBF by OSEM6 (0.98 +/- 0.48 [mean +/- SD]) and OSEM8 (0.96 +/- 0.46) was not significantly different from FBP (1.02 +/- 0.39), but OSEM2 (0.80 +/- 0.37) was significantly lower (P < 0.0003). With stress, the correlations were high between FBP and OSEM6 and OSEM8 (r2 = 0.85 and 0.90), and MBF by OSEM6 and OSEM8 was not significantly different from FBP. Part 2: Resting MBF correlated well between FBP and all OSEM smoothing filters (r2 = 0.82, 0.85, and 0.88). Rest MBF using postsmoothing 5- or 10-mm filters was not different from FBP but was significantly lower with the 15-mm filter (P < 0.05). With stress, the correlations were good between FBP and OSEM regardless of smoothing (r2 = 0.76, 0.77, and 0.79). However, MBF with postsmoothing 10- and 15-mm filters was significantly lower than by FBP (P < 0.05). CONCLUSION Reconstruction algorithms significantly affect the estimation of quantitative blood flow data and should not be assumed to be interchangeable. Although aggressive smoothing may produce visually appealing images with reduced noise levels, it may cause an underestimation of absolute quantitative MBF. In selecting a reconstruction algorithm, an optimal balance between noise properties and diagnostic accuracy must be emphasized.
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Affiliation(s)
- Grace P. Chen
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington
| | - Kelley R. Branch
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington
| | - Adam M. Alessio
- Department of Radiology, University of Washington, Seattle, Washington
| | - Pam Pham
- Department of Radiology, University of Washington, Seattle, Washington
| | - Ramin Tabibiazar
- Division of Cardiology, Department of Medicine, University of California, Los Angeles, California
| | - Paul Kinahan
- Department of Radiology, University of Washington, Seattle, Washington
| | - James H. Caldwell
- Division of Cardiology, Department of Medicine, University of Washington, Seattle, Washington
- Department of Radiology, University of Washington, Seattle, Washington
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Lortie M, Beanlands RSB, Yoshinaga K, Klein R, Dasilva JN, DeKemp RA. Quantification of myocardial blood flow with 82Rb dynamic PET imaging. Eur J Nucl Med Mol Imaging 2007; 34:1765-74. [PMID: 17619189 DOI: 10.1007/s00259-007-0478-2] [Citation(s) in RCA: 309] [Impact Index Per Article: 18.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Accepted: 04/22/2007] [Indexed: 10/23/2022]
Abstract
PURPOSE The PET tracer (82)Rb is commonly used to evaluate regional perfusion defects for the diagnosis of coronary artery disease. There is limited information on the quantification of myocardial blood flow and flow reserve with this tracer. The goal of this study was to investigate the use of a one-compartment model of (82)Rb kinetics for the quantification of myocardial blood flow. METHODS Fourteen healthy volunteers underwent rest and dipyridamole stress imaging with both (13)N-ammonia and (82)Rb within a 2-week interval. Myocardial blood flow was estimated from the time-activity curves measured with (13)N-ammonia using a standard two-compartment model. The uptake parameter of the one-compartment model was estimated from the time-activity curves measured with (82)Rb. To describe the relationship between myocardial blood flow and the uptake parameter, a nonlinear extraction function was fitted to the data. This function was then used to convert estimates of the uptake parameter to flow estimates. The extraction function was validated with an independent data set obtained from 13 subjects with documented evidence of coronary artery disease (CAD). RESULTS The one-compartment model described (82)Rb kinetics very well (median R-square = 0.98). The flow estimates obtained with (82)Rb were well correlated with those obtained with (13)N-ammonia (r = 0.85), and the best-fit line did not differ significantly from the identity line. Data obtained from the subjects with CAD confirmed the validity of the estimated extraction function. CONCLUSION It is possible to obtain accurate estimates of myocardial blood flow and flow reserve with a one-compartment model of (82)Rb kinetics and a nonlinear extraction function.
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Affiliation(s)
- Mireille Lortie
- Cardiac PET Centre, University of Ottawa Heart Institute, 40 Ruskin St., Ottawa, ON K1Y 4W7, Canada
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Alessio AM, Kohlmyer S, Branch K, Chen G, Caldwell J, Kinahan P. Cine CT for attenuation correction in cardiac PET/CT. J Nucl Med 2007; 48:794-801. [PMID: 17475969 PMCID: PMC2585486 DOI: 10.2967/jnumed.106.035717] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
UNLABELLED In dual-modality PET/CT systems, the CT scan provides the attenuation map for PET attenuation correction. The current clinical practice of obtaining a single helical CT scan provides only a snapshot of the respiratory cycle, whereas PET occurs over multiple respiratory cycles. Misalignment of the attenuation map and emission image because of respiratory motion causes errors in the attenuation correction factors and artifacts in the attenuation-corrected PET image. To rectify this problem, we evaluated the use of cine CT, which acquires multiple low-dose CT images during a respiratory cycle. We evaluated the average and the intensity-maximum image of cine CT for cardiac PET attenuation correction. METHODS Cine CT data and cardiac PET data were acquired from a cardiac phantom and from multiple patient studies. The conventional helical CT, cine CT, and PET data of an axially translating phantom were evaluated with and without respiratory motion. For the patient studies, we acquired 2 cine CT studies for each PET acquisition in a rest-stress (13)N-ammonia protocol. Three readers visually evaluated the alignment of 74 attenuation image sets versus the corresponding emission image and determined whether the alignment provided acceptable or unacceptable attenuation-corrected PET images. RESULTS In the phantom study, the attenuation correction from helical CT caused a major artifactual defect in the lateral wall on the PET image. The attenuation correction from the average and from the intensity-maximum cine CT images reduced the defect by 20% and 60%, respectively. In the patient studies, 77% of the cases using the average of the cine CT images had acceptable alignment and 88% of the cases using the intensity maximum of the cine CT images had acceptable alignment. CONCLUSION Cine CT offers an alternative to helical CT for compensating for respiratory motion in the attenuation correction of cardiac PET studies. Phantom studies suggest that the average and the intensity maximum of the cine CT images can reduce potential respiration-induced misalignment errors in attenuation correction. Patient studies reveal that cine CT provides acceptable alignment in most cases and suggest that the intensity-maximum cine image offers a more robust alternative to the average cine image.
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Affiliation(s)
- Adam M Alessio
- Department of Radiology, University of Washington, Seattle, WA 98195-7987, USA.
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Affiliation(s)
- Marcelo F Di Carli
- Division of Nuclear Medicine/PET, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Abstract
Integrated positron emission tomography computed tomography (PET/CT) scanners allow a true integration of the structure and function of the heart. Myocardial perfusion PET provides a high sensitivity (91%) and specificity (89%) for the diagnosis of obstructive coronary artery disease (CAD). But, as with single photon emission CT, relative perfusion PET often uncovers only the territory subtended by the most severe coronary stenosis, leading to underestimation of the extent of CAD. In contrast, quantitative PET provides a noninvasive assessment of myocardial blood flow and coronary flow reserve and improves detection of preclinical and multivessel coronary atherosclerosis. Similarly, CT coronary angiography is an accurate means to image the entire continuum of anatomic coronary atherosclerosis from nonobstructive to obstructive CAD. However, not all coronary stenoses are hemodynamically significant and <50% of the patients with obstructive CAD on CT angiography demonstrate stress induced perfusion defects. Stress PET data complement the anatomic information on the CT angiogram by providing instant readings about the ischemic burden of coronary stenoses. Thus, combined PET/CT may be potentially superior to CT angiography alone for the guiding revascularization decisions. Further, fusion of the PET and CT angiogram images allows identification of the culprit stenosis in patients presenting with chest pain. Finally, the advances in molecular imaging and image fusion may soon make noninvasive detection of vulnerable coronary plaques a clinical reality. In summary, integrated PET/CT is a powerful new noninvasive modality that offers the potential for refined diagnosis and management of the entire spectrum of coronary atherosclerosis.
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Affiliation(s)
- Marcelo F Di Carli
- Division of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
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Machac J, Bacharach SL, Bateman TM, Bax JJ, Beanlands R, Bengel F, Bergmann SR, Brunken RC, Case J, Delbeke D, DiCarli MF, Garcia EV, Goldstein RA, Gropler RJ, Travin M, Patterson R, Schelbert HR. Positron emission tomography myocardial perfusion and glucose metabolism imaging. J Nucl Cardiol 2007; 13:e121-51. [PMID: 17174789 DOI: 10.1016/j.nuclcard.2006.08.009] [Citation(s) in RCA: 104] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Yoshinaga K, Beanlands RSB, Dekemp RA, Lortie M, Morin J, Aung M, McKelvie R, Davies RF. Effect of exercise training on myocardial blood flow in patients with stable coronary artery disease. Am Heart J 2006; 151:1324.e11-8. [PMID: 16781249 DOI: 10.1016/j.ahj.2006.03.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/15/2005] [Accepted: 03/20/2006] [Indexed: 11/22/2022]
Abstract
BACKGROUND The mechanisms by which exercise training benefits patients with coronary artery disease (CAD) are unclear but may include improved myocardial circulation. The aim of this study was to investigate the effect of exercise training on myocardial blood flow (MBF) and coronary flow reserve (CFR) in patients with stable CAD. METHODS Twelve patients with documented CAD and ischemic ST-segment depression during exercise testing were randomized to exercise training (n = 7) or sedentary life style (control; n = 5) and underwent rubidium-82 positron emission tomography pre- and postintervention. Global left ventricle MBF and regional MBF in 17 left ventricular segments were calculated. Segments with <75% uptake (2 SD below normal) on stress uptake images were defined as abnormal. RESULTS Exercise training increased global CFR by 20.8% +/- 27.9% versus control (10.5 +/- 24.1%, P = .0001). In normal segments (exercise training: n = 91; control: n = 46), exercise training did not change resting MBF (-14.1% +/- 16.3% vs -8.8% +/- 15.6%) and hyperemic MBF (-1.93% +/- 19.1% vs 2.86% +/- 20.5%, P = NS) and increased in CFR compared to control (17.0% +/- 25.5% vs 11.3% +/- 23.5%, P = .01). In abnormal segments, the change in resting MBF was not significantly different (-12.6% +/- 18.5% exercise [28 segments] vs -2.9% +/- 18.0% control [39 segments], P = NS). A significant increase was seen in hyperemic MBF with exercise (12.5% +/- 22.1% vs 2.6% +/- 16.3%, P = .02) and CFR (32.8% +/- 32.3% vs 9.5% +/- 24.8%, P = .001). CONCLUSIONS Exercise training increased CFR in normal and diseased segments, and increased hyperemic flow in diseased segments. These data provide preliminary evidence in support of a favorable effect of exercise training on blood flow to ischemic myocardium.
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Affiliation(s)
- Keiichiro Yoshinaga
- Division of Cardiology, University of Ottawa Heart Institute, Ottawa, Ontario, Canada
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59
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Hickey KT, Sciacca RR, Chou RL, Rodriguez O, Bokhari S, Bergmann SR. An improved model for the measurement of myocardial perfusion in human beings using N-13 ammonia. J Nucl Cardiol 2005; 12:311-7. [PMID: 15944536 DOI: 10.1016/j.nuclcard.2005.01.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
BACKGROUND Oxygen 15 water and nitrogen 13 ammonia are widely used for the quantitative measurement of myocardial perfusion with positron emission tomography. However, blood flow obtained with N-13 ammonia by use of the conventional 2-compartment model frequently underestimates flow by 30% to 50% compared with O-15 water. We hypothesized that this discrepancy is a result of the model configuration of N-13 ammonia and investigated changes to the mathematical model to determine whether more accurate measurements of perfusion could be obtained. METHODS AND RESULTS Twelve healthy volunteers were sequentially studied with O-15 water and N-13 ammonia at rest and during maximal coronary vasodilation with adenosine. Perfusion measurements obtained with the conventional and modified models were compared with values obtained with O-15 water. The conventional N-13 ammonia model underestimated flow by 37% +/- 16% at rest and by 20% +/- 24% with stress when compared with flows obtained with O-15 water. The modified model yielded flow values closer to the line of identity than the conventional model (y = 1.07x + 0.04 vs y = 0.69x + 0.08; respectively; P < .01). CONCLUSIONS Model changes made N-13 ammonia myocardial blood flow estimates more comparable to those obtained with O-15 and may allow for better comparison of flows obtained with these two tracers in the future. Further efforts are warranted to evaluate the accuracy of flow models in human subjects.
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Affiliation(s)
- Kathleen T Hickey
- Department of Medicine, Division of Cardiology, College of Physicians & Surgeons of Columbia University, New York, NY 10032, USA.
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Abstract
Myocardial perfusion imaging with single-photon emission CT (SPECT) is a key investigation in the work-up of patients with coronary artery disease. PET, however, with inherently better spatial and temporal resolution, offers several advantages over SPECT. The last decade has witnessed extensive application of PET techniques to assess myocardial viability and has provided valuable information important in analyzing the risk: benefit ratio for several therapeutic measures. Recent advances in PET instrumentation and radiopharmaceuticals have generated considerable interest to use PET for evaluating an array of cardiovascular disease.
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Affiliation(s)
- Amol Takalkar
- Division of Nuclear Medicine, Department of Radiology, Hospital of the University of Pennsylvania, 110 Donner Building, 3400 Spruce Street, Philadelphia, PA 19104, USA
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61
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Affiliation(s)
- Marcelo F Di Carli
- Department of Nuclear Medicine, Department of Radiology, Brigham and Women's Hospital, 75 Francis Street, Boston, MA, USA.
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Hirata K, Amudha K, Elina R, Hozumi T, Yoshikawa J, Homma S, Lang CC. Measurement of coronary vasomotor function: getting to the heart of the matter in cardiovascular research. Clin Sci (Lond) 2004; 107:449-60. [PMID: 15362973 DOI: 10.1042/cs20040226] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Measurement of endothelial function in patients has emerged as a useful tool for cardiovascular research. Although no gold standard for the measurement of endothelial function exists, the measurement of flow-mediated dilation in the brachial artery, assessed with Doppler ultrasonography, is the most studied method. However, the assumption that endothelial dysfunction detected in brachial arteries is a manifestation of systemic endothelial dysfunction including the coronary circulation may not be entirely valid. Brachial and myocardial circulations differ in terms of the microvascular architecture, the pattern of blood flow and vascular resistance (e.g. shunt vessels occur in the hand but not in the myocardium), their metabolic regulation, type of receptors that contribute to humoral regulation and the pathways that are activated to induce hyperaemia. In this context, measuring coronary vasomotor function may be more useful than brachial artery measures to predict and assess potential myocardial damage related to limited vascular responsiveness. This review aims to provide an overview of the basic concept of coronary flow reserve and its different modalities of measurement, as well as its utility in cardiovascular research.
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Affiliation(s)
- Kumiko Hirata
- Division of Cardiology, Columbia University, New York, USA
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63
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Parkash R, deKemp RA, Ruddy TD, Kitsikis A, Hart R, Beauchesne L, Beauschene L, Williams K, Davies RA, Labinaz M, Beanlands RSB. Potential utility of rubidium 82 PET quantification in patients with 3-vessel coronary artery disease. J Nucl Cardiol 2004; 11:440-9. [PMID: 15295413 DOI: 10.1016/j.nuclcard.2004.04.005] [Citation(s) in RCA: 184] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
BACKGROUND Standard perfusion imaging may underestimate the extent of disease in 3-vessel coronary atherosclerosis. This study determined whether positron emission tomography quantification of perfusion reserve by use of rubidium 82 net retention defined a greater extent of disease than the standard approach in patients with 3-vessel disease. METHODS AND RESULTS Rb-82 net retention was quantified as an estimation of absolute perfusion at rest and with dipyridamole stress by use of dynamic positron emission tomography imaging. The percent of abnormal myocardial sectors, as compared with a normal database, for a standard and quantification approach was determined. Twenty-three patients were evaluated. Defect sizes were larger in patients with 3-vessel disease (n = 13) by use of quantification methods: 44% +/- 18% of the myocardial sectors were abnormal by use of the standard approach versus 69% +/- 24% of sectors when measured by quantification of the stress-rest perfusion difference (P =.008). In patients with single-vessel disease (n = 10), defect sizes were smaller with quantification methods. CONCLUSIONS Quantification of Rb-82 net retention to measure the stress-rest perfusion difference in the myocardium defined a greater extent of disease than the standard approach in this group of patients with triple-vessel disease. More accurate measurement of the extent of coronary artery disease could facilitate better risk stratification and identify more high-risk patients in whom aggressive intervention is required.
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Affiliation(s)
- R Parkash
- Cardiac PET Center, Department of Medicine, University of Ottawa Heart Institute, Ontario, Canada
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Pirich C, Leber A, Knez A, Bengel FM, Nekolla SG, Haberl R, Schwaiger M. Relation of coronary vasoreactivity and coronary calcification in asymptomatic subjects with a family history of premature coronary artery disease. Eur J Nucl Med Mol Imaging 2004; 31:663-70. [PMID: 14740179 DOI: 10.1007/s00259-003-1426-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2003] [Accepted: 11/14/2003] [Indexed: 10/26/2022]
Abstract
Electron-beam computed tomography (EBCT) allows non-invasive imaging of coronary calcification and has been promoted as a screening tool for coronary artery disease (CAD) in asymptomatic high-risk subjects. This study assessed the relation of coronary calcifications to alterations in coronary vascular reactivity by means of positron emission tomography (PET) in asymptomatic subjects with a familial history of premature CAD. Twenty-one subjects (mean age 51+/-10 years) underwent EBCT imaging for coronary calcifications expressed as the coronary calcium score (CCS according to Agatston) and rest/adenosine-stress nitrogen-13 ammonia PET with quantification of myocardial blood flow (MBF) and coronary flow reserve (CFR). The mean CCS was 237+/-256 (median 146, range 0-915). The CCS was <100 in eight subjects and >100 units in 13. As defined by age-related thresholds, 15 subjects had an increased CCS (>75th percentile). Overall mean resting and stress MBF and CFR were 71+/-16 ml 100 g(-1) min(-1), 218+/-54 ml 100 g(-1) min(-1) and 3.20+/-0.77, respectively. Three subjects with CCS ranging from 114 to 451 units had an abnormal CFR (<2.5). There was no relation between CCS and resting or stress MBF or CFR ( r=0.17, 0.18 and 0.10, respectively). In asymptomatic subjects a pathological CCS was five times more prevalent than an abnormal CFR. The absence of any close relationship between CCS and CFR reflects the fact that quantitative myocardial perfusion imaging with PET characterises the dynamic process of vascular reactivity while EBCT is a measure of more stable calcified lesions in the arterial wall whose presence is closely related to age.
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Affiliation(s)
- Christian Pirich
- Nuklearmedizinische Klinik und Poliklinik der Technischen Universität München, Germany.
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Campisi R, Di Carli MF. Assessment of coronary flow reserve and microcirculation: a clinical perspective. J Nucl Cardiol 2004; 11:3-11. [PMID: 14752466 DOI: 10.1016/j.nuclcard.2003.11.003] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Bacharach SL, Bax JJ, Case J, Delbeke D, Kurdziel KA, Martin WH, Patterson RE. Pet myocardial glucose metabolism and perfusion imaging: Part I — Guidelines for patient preparation and data acquisition. J Nucl Cardiol 2003. [DOI: 10.1007/bf02970271] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Fuster V, Corti R, Fayad ZA, Schwitter J, Badimon JJ. Integration of vascular biology and magnetic resonance imaging in the understanding of atherothrombosis and acute coronary syndromes. J Thromb Haemost 2003; 1:1410-21. [PMID: 12871275 DOI: 10.1046/j.1538-7836.2003.00271.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The interaction between the vulnerable atherosclerotic plaque prone to disruption and thrombus formation is the cornerstone of acute coronary syndrome (ACS). Although distinct from one another, the atherosclerotic and thrombotic processes appear to be interdependent, hence the term atherothrombosis. Inflammation is a crucial common pathophysiological mechanism. Overall, the association of plaque vulnerability and ACS has been well documented. Given the multifactorial origin of atherothrombosis the best preventive approach should be aggressive management of all the risk factors. New interventions should be directed toward decreasing vulnerability of the lesions thereby decreasing the risk of ACS.
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Affiliation(s)
- V Fuster
- Mount Sinai School of Medicine, New York, NY 10029, USA.
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Schindler TH, Nitzsche E, Magosaki N, Brink I, Mix M, Olschewski M, Solzbach U, Just H. Regional myocardial perfusion defects during exercise, as assessed by three dimensional integration of morphology and function, in relation to abnormal endothelium dependent vasoreactivity of the coronary microcirculation. Heart 2003; 89:517-26. [PMID: 12695456 PMCID: PMC1767646 DOI: 10.1136/heart.89.5.517] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/20/2002] [Indexed: 12/24/2022] Open
Abstract
OBJECTIVE To test the hypothesis that scintigraphic regional myocardial perfusion defects during exercise in patients with normal coronary angiography may be related to abnormal endothelium dependent vasoreactivity of the corresponding myocardial territory in response to cold pressor testing. METHODS 38 patients were classified into two groups according to the presence or absence of exercise induced scintigraphic myocardial perfusion defects. A cold pressor test was done in all patients during routine coronary angiography, followed by dynamic positron emission tomography to establish coronary blood flow mediated vasoreactivity of the epicardial coronary artery and the myocardial territories supplied by the left anterior descending, left circumflex, and right coronary arteries. RESULTS 28 patients had regional myocardial perfusion defects while 10 had normal scintigraphic imaging. The three dimensional scintigraphic fusion image revealed 49 regional myocardial perfusion defects with a mean (SD) reversibility of the original stress defect of 20 (3)%. In patients with exercise induced regional myocardial perfusion defects, the responses of epicardial luminal area and regional myocardial blood flow (RMBF) to cold pressor testing were reduced compared with patients with normal perfusion imaging (epicardial luminal area: 5.2 (1.2) to 4.2 (0.86) mm2 v 4.7 (0.5) to 5.8 (0.5) mm2; RMBF: 0.75 (0.16) to 0.78 (0.20) ml/g/min v 0.75 (0.15) to 1.38 (0.26) ml/g/min; p < or = 0.03, respectively). In patients with regional abnormal scintigraphic perfusion, the corresponding RMBF response to cold pressor testing was more severely impaired than the mean myocardial blood flow in the remaining two vascular territories, but the difference was not significant (0.75 (0.16) to 0.78 (0.20) ml/g/min v 0.75 (0.10) to 0.87 (0.12) ml/g/min; NS). The endothelium independent increase in RMBF induced by glyceryl trinitrate did not differ between patients with exercise induced myocardial perfusion defects and those with normal perfusion images (0.75 (0.16) to 0.94 (0.09) ml/g/min v 0.75 (0.15) to 0.94 (0.09) ml/g/min; NS). There was a highly significant correlation between the endothelium dependent responses of RMBF to cold pressor testing and the severity of exercise induced scintigraphic regional myocardial perfusion defects (r = 0.95, p = 0.001). CONCLUSIONS Exercise induced scintigraphic regional myocardial perfusion defects in patients with angina but normal coronary angiography may be related to abnormal endothelium dependent vasoreactivity of the corresponding myocardial territory.
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Affiliation(s)
- T H Schindler
- Zentrum für Klinische Forschung II, Albert-Ludwig-Universität Freiburg, Germany
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69
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70
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Abstract
The interaction between the vulnerable atherosclerotic plaque and thrombus formation, a process referred to as atherothrombosis, is the cornerstone of acute coronary syndromes. Advances in noninvasive imaging have helped to identify novel approaches to plaque stabilization, with the potential to prevent plaque rupture, including lifestyle modification and dietary adjustments, as well as pharmacologic interventions such as statins. Following an acute coronary event, strategies combining mechanical and pharmacologic therapies provide considerable advances in prevention of subsequent cardiac events. Pharmacologic strategies to prevent and treat thrombotic complications related to acute coronary syndromes have been developed to dissolve preformed thrombi and to inhibit thrombogenesis. These regimens focus on inhibiting thrombin, preventing thrombi generation, blocking the initiation of coagulation, inhibiting platelet activation, and increasing fibrinolysis.
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Affiliation(s)
- Roberto Corti
- Cardiovascular Biology Research Laboratory, Mount Sinai School of Medicine, New York, New York, USA
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71
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Beanlands RSB, Ruddy TD, deKemp RA, Iwanochko RM, Coates G, Freeman M, Nahmias C, Hendry P, Burns RJ, Lamy A, Mickleborough L, Kostuk W, Fallen E, Nichol G. Positron emission tomography and recovery following revascularization (PARR-1): the importance of scar and the development of a prediction rule for the degree of recovery of left ventricular function. J Am Coll Cardiol 2002; 40:1735-43. [PMID: 12446055 DOI: 10.1016/s0735-1097(02)02489-0] [Citation(s) in RCA: 167] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES The aim of this study was to determine whether the extent of viability or scar is important in the amount of recovery of left ventricular (LV) function, and to develop a model for predicting recovery after revascularization that could be tested in a randomized trial. BACKGROUND F-18-fluorodeoxyglucose (FDG) positron emission tomography (PET) is used to define viable myocardium in patients with coronary artery disease (CAD) and severe LV dysfunction and to guide revascularization decisions. Whether this approach improves clinical outcomes has not been tested in a randomized trial. Before doing so, an objective model for prediction of recovery is required. METHODS A total of 82 patients with CAD and an ejection fraction (EF) < or =35% had FDG PET perfusion imaging before revascularization. Complete follow-up was available on 70 patients (86%). Patients had radionuclide angiograms at baseline and three months post-revascularization. RESULTS Diabetes (p = 0.029), time to operation (p = 0.008), and scar score (p = 0.001) were significant independent predictors of the change in EF. Previous coronary artery bypass graft confounded the effect of age. There was a significant interaction between the perfusion tracer used and mismatch score (p = 0.02). The multivariable prediction model incorporating PET and clinical variables had a goodness of fit with p = 0.001. Across tertiles of scar scores (I, small: 0% to 16%; II, moderate: 16% to 27.5%; III, large: 27.5% to 47%), the changes in EFs were 9.0 +/- 1.9%, 3.7 +/- 1.6%, and 1.3 +/- 1.5% (p = 0.003: I vs. III), respectively. CONCLUSIONS In patients with severe LV dysfunction, the amount of scar was a significant independent predictor of LV function recovery after revascularization. A combination of PET and clinical parameters predicts the degree of recovery. This model is being applied in a large randomized controlled trial to determine the effectiveness of therapy guided by FDG PET.
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Affiliation(s)
- Rob S B Beanlands
- Cardiac PET Centre, Divisions of Cardiology and Cardiac Surgery, University of Ottawa Heart Institute, 40 Ruskin Street, Ottawa, Ontario K1Y 4W7, Canada.
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72
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Fuster V, Corti R, Badimon JJ. The Mikamo Lecture 2002. Therapeutic targets for the treatment of atherothrombosis in the new millennium--clinical frontiers in atherosclerosis research. Circ J 2002; 66:783-90. [PMID: 12224812 DOI: 10.1253/circj.66.783] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Valentin Fuster
- The Zena and Michael Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, NY 10029, USA.
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73
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Abstract
Noninvasive vascular imaging may identify the high-risk, asymptomatic atherosclerotic patient who will substantially benefit from aggressive preventive therapies. Endothelium is a key player in the early stages of atherogenesis. Positron emission tomography (PET) and ultrasound-measured brachial artery vasoreactivity have emerged as potentially useful tools for the identification of endothelial dysfunction and, as such, early atherosclerosis. Both have been used successfully to demonstrate the association between endothelial dysfunction and established coronary artery disease risk factors, as well as clinically evident coronary artery disease. Abnormal coronary endothelial function recently has been associated with poor clinical outcomes in long-term follow-up studies. Given the close association between endothelial function in the coronary and peripheral circulation, there is particular promise for the validation of brachial artery vasoreactivity as a clinically useful tool. Finally, surveillance of endothelial function with these techniques may prove helpful in guiding aggressiveness of antiatherosclerotic therapy and effectiveness of new regimens.
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Affiliation(s)
- Daniel Edmundowicz
- Comprehensive Heart Center, University of Pittsburgh School of Medicine, 120 Lytton Avenue, Suite 302, Pittsburgh, PA 15213, USA.
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74
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Ibrahim T, Nekolla SG, Schreiber K, Odaka K, Volz S, Mehilli J, Güthlin M, Delius W, Schwaiger M. Assessment of coronary flow reserve: comparison between contrast-enhanced magnetic resonance imaging and positron emission tomography. J Am Coll Cardiol 2002; 39:864-70. [PMID: 11869854 DOI: 10.1016/s0735-1097(01)01829-0] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
OBJECTIVES The study compared flow reserve indices by magnetic resonance imaging (MRI) with quantitative measures of coronary angiography and positron emission tomography (PET). BACKGROUND The noninvasive evaluation of myocardial flow by MRI has recently been introduced. However, a comparison to quantitative flow measurement as assessed by PET has not been reported in patients with coronary artery disease (CAD). METHODS Two groups of healthy volunteers and 25 patients with angiographically documented CAD were examined by MRI and PET at rest and during adenosine stress. Dynamic MRI was performed using a multi-slice ultra-fast hybrid sequence and a rapid gadolinium-diethylenetriaminepenta-acetic acid bolus injection (0.05 mmol/l). Upslope and peak-intensity indices were regionally determined from first-pass signal intensity curves and compared to N-13 ammonia PET flow reserve measurements. RESULTS In healthy volunteers, the upslope analysis showed a stress/rest index of 2.1 plus minus 0.6, which was higher than peak intensity (1.5 plus minus 0.3), but lower than flow reserve by PET (3.9 plus minus 1.1). Localization of coronary artery stenoses (> 75%, MRI < 1.2), based on the upslope index, yielded sensitivity, specificity and diagnostic accuracy of 69%, 89% and 79%, respectively. Upslope index correlated with PET flow reserve (r = 0.70). A reduced coronary flow reserve (PET < 2.0, MRI < 1.3) was detected by the upslope index with sensitivity, specificity and diagnostic accuracy of 86%, 84% and 85%, respectively. CONCLUSIONS Magnetic resonance imaging first-pass perfusion measurements underestimate flow reserve values, but may represent a promising semi-quantitative technique for detection and severity assessment of regional CAD.
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Affiliation(s)
- Tareq Ibrahim
- Nuklearmedizinische Klinik und Poliklinik der Technischen Universität München, Munich, Germany
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75
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Corti R, Fuster V, Badimon JJ, Hutter R, Fayad ZA. New understanding of atherosclerosis (clinically and experimentally) with evolving MRI technology in vivo. Ann N Y Acad Sci 2001; 947:181-95; discussion 195-8. [PMID: 11795266 DOI: 10.1111/j.1749-6632.2001.tb03940.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Atherosclerosis and its thrombotic complications are the major cause of morbidity and mortality in industrialized countries. Despite advances in our understanding of the pathogenetic mechanisms and new treatment modalities, the absence of an adequate noninvasive method for early detection limits the prevention or treatment of patients with various degrees and localizations of atherothrombotic disease. High-resolution magnetic resonance (MR) has recently emerged as one of the most promising techniques for the noninvasive study of atherothrombotic disease. Most importantly, MR can be used to characterize plaque composition and monitor progression. Thus, MR opens new strategies, ranging from the screening of high-risk patients for early detection and treatment as well as the monitoring of target areas for pharmacological intervention.
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Affiliation(s)
- R Corti
- The Zena and Michael Wiener Cardiovascular Institute, Mount Sinai School of Medicine, New York, New York 10029, USA
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76
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Sambuceti G, Marzilli M, Fedele S, Marini C, L'Abbate A. Paradoxical Increase in Microvascular Resistance During Tachycardia Downstream From a Severe Stenosis in Patients With Coronary Artery Disease. Circulation 2001; 103:2352-60. [PMID: 11352883 DOI: 10.1161/01.cir.103.19.2352] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background
—The pathophysiology of microvascular response to a severe coronary stenosis has not been conclusively identified. The aim of this study was to characterize the human vasomotor response to pacing-induced ischemia of both the stenotic arterial segment and the distal microcirculation.
Methods and Results
—Sixteen patients with stable angina and single-vessel disease were studied. Blood flow velocity and transstenotic pressure gradient were monitored at baseline, after intracoronary adenosine (2 mg), and during ischemia induced by atrial pacing with and without adenosine. At the end of this protocol, the study was repeated after intracoronary phentolamine in 7 patients and after angioplasty in 9. Stenosis resistance was calculated as the ratio between mean pressure gradient and mean flow, and microvascular resistance as the ratio between mean distal pressure and mean flow; values were expressed as percent of baseline. Adenosine decreased (
P
<0.05) baseline microvascular resistance to 52±17%, but not stenosis resistance. Pacing increased both stenosis and microvascular resistances (244±96% and 164±60% of baseline, respectively,
P
<0.05). Addition of adenosine to pacing decreased both stenosis (143±96% of baseline,
P
<0.05 versus ischemia) and microvascular (51±17% of baseline,
P
<0.05 versus baseline and ischemia) resistances. Phentolamine did not affect coronary resistance at any step of the protocol. Angioplasty and stenting restored a progressive decline in microvascular resistance during pacing (51±19% of baseline,
P
<0.05 versus baseline).
Conclusions
—In patients with coronary artery disease, tachycardia-induced ischemia was associated with elevated resistance of both the stenotic segment and the microvasculature. Revascularization prevents this paradoxical behavior.
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Affiliation(s)
- G Sambuceti
- CNR Institute of Clinical Physiology, Pisa, Italy.
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77
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Kaufmann PA, Gnecchi-Ruscone T, di Terlizzi M, Schäfers KP, Lüscher TF, Camici PG. Coronary heart disease in smokers: vitamin C restores coronary microcirculatory function. Circulation 2000; 102:1233-8. [PMID: 10982536 DOI: 10.1161/01.cir.102.11.1233] [Citation(s) in RCA: 150] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND Coronary endothelial function and vasomotion are impaired in smokers without coronary disease, and this is thought to be due to increased oxidative stress. METHODS AND RESULTS We used positron emission tomography to measure the coronary flow reserve, an integrated measure of coronary flow, through both the large epicardial coronary arteries and the microcirculation in 11 smokers and 8 control subjects before and after administration of the antioxidant vitamin C. At baseline, coronary flow reserve was reduced by 21% in smokers compared with control subjects (P:<0.05) but was normalized after vitamin C, whereas the drug had no effect in control subjects. CONCLUSIONS The present study is the first to demonstrate that the noxious prooxidant effects of smoking extend beyond the epicardial arteries to the coronary microcirculation and affect the regulation of myocardial blood flow. Vitamin C restores coronary microcirculatory responsiveness and impaired coronary flow reserve in smokers, which provides evidence that the damaging effect of smoking is at least in part accounted for by an increased oxidative stress.
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Affiliation(s)
- P A Kaufmann
- MRC Clinical Sciences Centre, Imperial College School of Medicine, Hammersmith Hospital, London, UK
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78
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79
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Gould KL, Nakagawa Y, Nakagawa K, Sdringola S, Hess MJ, Haynie M, Parker N, Mullani N, Kirkeeide R. Frequency and clinical implications of fluid dynamically significant diffuse coronary artery disease manifest as graded, longitudinal, base-to-apex myocardial perfusion abnormalities by noninvasive positron emission tomography. Circulation 2000; 101:1931-9. [PMID: 10779459 DOI: 10.1161/01.cir.101.16.1931] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Diffuse coronary atherosclerosis is the substrate for plaque rupture and coronary events. Therefore, in patients with mild arteriographic coronary artery disease without significant segmental dipyridamole-induced myocardial perfusion defects, we tested the hypothesis that fluid dynamically significant diffuse coronary artery narrowing is frequently manifest as a graded, longitudinal, base-to-apex myocardial perfusion abnormality by noninvasive PET. METHODS AND RESULTS In this study, 1001 patients with documented coronary artery disease by coronary arteriography showing any visible coronary artery narrowing underwent rest-dipyridamole PET perfusion imaging. Quantitative severity of dipyridamole-induced, circumscribed, segmental PET perfusion defects was objectively measured by automated software as the minimum quadrant average relative activity indicating localized flow limiting stenoses. Quantitative severity of the graded, longitudinal, base-to-apex myocardial perfusion gradient indicating fluid dynamic effects of diffuse coronary artery narrowing was objectively measured by automated software as the spatial slope of relative activity along the cardiac longitudinal axis. CONCLUSIONS In patients with mild arteriographic disease without statistically significant dipyridamole-induced segmental myocardial perfusion defects caused by flow-limiting stenoses compared with normal control subjects, there was a graded, longitudinal, base-to-apex myocardial perfusion gradient significantly different from normal control subjects (P=0. 001) that was also observed for moderate to severe dipyridamole-induced segmental perfusion defects (P=0.0001), indicating diffuse disease underlying segmental perfusion defects; 43% of patients with or without segmental perfusion defects demonstrated graded, longitudinal, base-to-apex perfusion abnormalities beyond +/-2 SD of normal control subjects, indicating diffuse coronary arterial narrowing by noninvasive PET perfusion imaging.
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Affiliation(s)
- K L Gould
- Weatherhead PET Center for Preventing and Reversing Atherosclerosis, University of Texas Medical School, Houston, TX 77030, USA
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80
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Kosa I, Blasini R, Schneider-Eicke J, Dickfeld T, Neumann FJ, Ziegler S, Matsunari I, Neverve J, Schömig A, Schwaiger M. Early recovery of coronary flow reserve after stent implantation as assessed by positron emission tomography. J Am Coll Cardiol 1999; 34:1036-41. [PMID: 10520786 DOI: 10.1016/s0735-1097(99)00336-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The aim of this study was to quantitatively evaluate myocardial flow reserve in patients early after coronary stent implantation using positron emission tomography. BACKGROUND Delayed restoration of coronary flow reserve after percutaneous transluminal coronary angioplasty (PTCA) has been observed using a variety of techniques. Altered distal vasoregulation as well as residual stenosis have been considered possible explanations for this phenomenon. Although the implantation of stents may influence some of these mechanisms, little data are available characterizing coronary flow reserve early after stent placement. METHODS In 14 patients 1.6 +/- 0.6 days after stenting, N-13-ammonia positron emission tomographic studies were performed at rest and during adenosine-induced vasodilation. Myocardial blood flow was quantified using a three-compartment model. Rest and stress flow data, as well as coronary flow reserve of stented vascular territories, were compared with that of remote areas. RESULTS The stenosis decreased from 72.1 +/- 7.3% to 3.7 +/- 6.7% after stent implantation. Coronary flow in the stented areas did not differ significantly from that in remote areas either at rest (76.1 +/- 18.5 and 75.7 +/- 17.7 ml/min/100 g, respectively), or during maximal vasodilation (205.5 +/- 59.9 and 179.4 +/- 47.4 ml/min/100 g, respectively). In addition, there was no significant difference in the calculated values of coronary reserve of these two regions (2.74 +/- 0.64 and 2.43 +/- 0.55, respectively). CONCLUSIONS The mechanical support of dilated arteries by a stent not only restores the macroscopic integrity of epicardial arteries, but also results, in contrast to conventional PTCA procedures, in early recovery of flow reserve.
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Affiliation(s)
- I Kosa
- Department of Nuclear Medicine, Klinikum rechts der Isar, der Technische Universität, München, Germany
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81
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Guethlin M, Kasel AM, Coppenrath K, Ziegler S, Delius W, Schwaiger M. Delayed response of myocardial flow reserve to lipid-lowering therapy with fluvastatin. Circulation 1999; 99:475-81. [PMID: 9927392 DOI: 10.1161/01.cir.99.4.475] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Lipid-lowering therapy can improve endothelial function in patients with coronary artery disease (CAD) and hypercholesterolemia. Little is known about induced changes in myocardial microcirculation. This study prospectively investigated the temporal effects of lipid-lowering therapy with fluvastatin on coronary flow and flow reserve (CFR) in patients with CAD assessed by PET. METHODS AND RESULTS In an open clinical trial, CFR was studied in 15 patients with angiographically documented multivessel CAD and hypercholesterolemia (LDL >160 mg/dL). Dynamic 13N-labeled ammonia PET imaging in conjunction with adenosine was used to assess regional and global CFR at baseline as well as at 2 and 6 months during treatment with fluvastatin (60 to 80 mg/d). Despite a rapid decrease in total cholesterol (29+/-6%) and LDL (37+/-9%), myocardial blood flow at rest and during stress was unchanged after 2 months of treatment (2.7+/-0.9 versus 2.5+/-0.6 mL x g-1 x min-1). At 6 months, stress blood flow as well as CFR increased significantly (3.4+/-1.0 mL x g-1 x min-1). No change in hemodynamic parameters was noted during the entire study. Nine of 15 patients increased CFR by >20%. All responders demonstrated improvement in anginal symptoms, whereas nonresponders stated no change (n=4) or worsening of symptoms (n=2). The improvement in CFR was not related to the amount of lipid lowering and was independent of the severity of stenoses. CONCLUSIONS Improvement in stress blood flow and CFR is delayed compared with the lipid-lowering effect of fluvastatin, suggesting a slow recovery of the vasodilatory response to adenosine.
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Affiliation(s)
- M Guethlin
- Abteilung für Kardiologie, Klinikum München-Bogenhausen, München, Germany
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82
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Kranidis AI, Patsilinakos S, Filippatos G, Kappos K, Antonellis I, Bouki T, Tsiotika T, Anthopoulos P, Tsilias K, Anthopoulos L. Non-invasive evaluation of coronary reserve. Assessment of coronary reserve in patients with coronary artery disease by transesophageal-Doppler echocardiography. Int J Cardiol 1999; 68:107-13. [PMID: 10077407 DOI: 10.1016/s0167-5273(98)00333-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
We assessed coronary flow reserve using transesophageal Doppler echocardiography in patients with coronary artery disease. The study included 33 coronary artery disease patients who were undergoing coronary arteriography. The blood flow velocities of the left anterior descending artery before and after intravenous infusion (0.56 mg/min for 4 min) of dipyridamole were recorded using transesophageal Doppler echocardiography. Fourteen normal healthy individuals, matched for age, served as a control group. The index of coronary flow reserve, i.e. the ratio of dipyridamole to baseline maximum diastolic velocity, was calculated. Maximal coronary flow reserve in coronary artery disease patients was significantly lower than in the control group (1.4+/-0.2 vs. 2.8+/-0.3, P<0.001). The coronary artery disease patients were classified into three groups: Group A included 10 patients with <50% left anterior descending artery stenosis; Group B included seven patients with 50-69% left anterior descending artery stenosis; 16 patients with >70% left anterior descending artery stenosis constituted Group C. The maximum coronary flow reserve was significantly different for A vs. B and A vs. C. (A, 1.77+/-0.18; B, 1.51+/-0.1; C, 1.28+/-0.24). A strong and significant correlation was found between the maximum coronary flow reserve and the degree of proximal left anterior descending artery stenosis (r=0.78, P<0.001). Coronary artery disease patients without left anterior descending artery stenosis on the arteriogram exhibited lower maximum coronary flow reserve compared to the control subjects (1.78+/-0.19 vs. 2.8+/-0.3, P=0.000).
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Affiliation(s)
- A I Kranidis
- First Department of Cardiology, Evangelismos General Hospital, Athens, Greece
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83
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Baumgart D, Haude M, Goerge G, Ge J, Vetter S, Dagres N, Heusch G, Erbel R. Improved assessment of coronary stenosis severity using the relative flow velocity reserve. Circulation 1998; 98:40-6. [PMID: 9665058 DOI: 10.1161/01.cir.98.1.40] [Citation(s) in RCA: 81] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Myocardial fractional flow reserve (FFR) is based on pressure measurements. We have now sought to establish a Doppler-based concept of relative flow velocity reserve (RFVR) for the functional assessment of stenosis severity in epicardial coronary arteries. A clear threshold value to discriminate the functional severity of a coronary stenosis does not exist for coronary flow velocity reserve (CVR) based on intracoronary Doppler measurements. In contrast, the concept of FFR, which is based on intracoronary pressure measurements, has been extensively validated. An FFR value below 0.75 reliably indicates a significant stenosis. METHODS AND RESULTS RFVR is calculated as the ratio between distal CVR in the stenosed target vessel and distal CVR in a nonstenotic reference vessel. In 21 patients, RFVR was determined in 24 target vessels by use of intracoronary adenosine and correlated to the FFR, determined as the ratio of mean poststenotic to aortic pressures, in the target vessel. Stenosis severity was classified according to quantitative coronary angiography analysis. Reference diameter was 3.0+/-0.4 mm (mean+/-SD), and area stenosis was 74+/-15% (range, 40% to 95%). CVRs in the target and reference vessels were 2.1+/-0.5 and 2.6+/-0.7, respectively. FFR ranged from 0.49 to 0.99 (mean, 0.81+/-0.15) and RFVR from 0.53 to 1.0 (mean, 0.82+/-0.13). Poststenotic CVR did not correlate with either percent area stenosis (r=0.27, P=NS) or FFR (r=0.33, P=NS). In contrast, FFR as well as RFVR showed a curvilinear relation to percent area stenosis (r=0.89, P<0.0001 and r=0.79, P<0.0001, respectively). There was a close linear correlation between FFR and RFVR (r=0.91, P<0.0001). CONCLUSIONS RFVR correlates closely to FFR and to percent area stenosis, whereas the correlation of CVR with FFR and percent area stenosis is rather poor. RFVR is a promising new concept for assessment of coronary stenosis severity and clinical decision making based on Doppler measurements.
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Affiliation(s)
- D Baumgart
- Division of Cardiology, Center of Internal Medicine, University of Essen, Germany.
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84
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Baumgart D, Haude M, Liu F, Ge J, Goerge G, Erbel R. Current concepts of coronary flow reserve for clinical decision making during cardiac catheterization. Am Heart J 1998; 136:136-49. [PMID: 9665231 DOI: 10.1016/s0002-8703(98)70194-2] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Measurements of coronary flow reserve, once used only for research, have gained wide acceptance as an additional diagnostic approach in the decision-making process of diagnostic cardiac catheterization and coronary interventions. Apart from the noninvasive determination of coronary flow reserve, intracoronary Doppler flow wires have facilitated decision making in the catheterization laboratory. Different techniques, unstandardized procedures, and data from uncomparable patient populations have remained a confounding factor. This review examines current concepts of coronary flow reserve as well as methodologic considerations and pitfalls. Applications of coronary flow reserve for periinterventional assessment are evaluated on the background of practical guidance. According to a detailed examination of arterial structure and function, a normal coronary flow reserve exceeds a value of 3.0. Values below 3.0 suggest involvement of microvascular disease caused by functional or structural alterations. The influences of various factors such as age, hemodynamics, hypercholesterolemia, hypertrophy, hypertension, syndrome X, and coronary artery disease are discussed in relation to the effect on coronary flow reserve. From available information, measurements of coronary flow reserve are an adjunct to current interventional technology to optimize individual patient care. Further efforts should be undertaken to incorporate these new methods into our routine clinical decision making.
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Affiliation(s)
- D Baumgart
- Department of Cardiology, Center of Internal Medicine, University of Essen, Germany.
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85
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Jerosch-Herold M, Wilke N. MR first pass imaging: quantitative assessment of transmural perfusion and collateral flow. INTERNATIONAL JOURNAL OF CARDIAC IMAGING 1997; 13:205-18. [PMID: 9220283 DOI: 10.1023/a:1005784820067] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Recent advances with fast switching gradient coils, and the optimization of magnetic resonance techniques for multislice imaging have made it possible to apply models of contrast agent transit for the quantification of myocardial perfusion, and determination of the transmural distribution of blood flow. This article summarizes some of these recent developments and presents examples of quantitative, multi-slice myocardial perfusion imaging studies in patients and animal models. Multi-slice, true first pass imaging, with high temporal resolution, and T1-weighted, arrhythmia insensitive contrast enhancement is used for the quantification of perfusion changes accompanying mild to severe ischemia. The first pass imaging technique and the modeling approach are sufficiently robust for fitting of tissue residue curves corresponding to a wide, physiologically realistic range of myocardial blood flows. In animals this was validated by comparison to blood flow measurements with radiolabeled microspheres as gold standard. It is demonstrated that with the proposed modeling approach one can determine the myocardial perfusion reserve from two consecutive MR first pass measurements under resting and hyperemic conditions. In patients with microvascular dysfunction the MR studies show for the first time that the myocardial perfusion reserve correlates with Doppler flow measurements (linear regression with slope of 1.02 +/- 0.09; r = 0.80). Since perfusion limitations usually begin in the subendocardium as coronary flow is gradually reduced, first pass imaging with the prerequisitie spatial and temporal resolution allows early detection of a mild coronary stenosis.
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Affiliation(s)
- M Jerosch-Herold
- Department of Radiology, University of Minnesota, Minneapolis 55455, USA
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86
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Borchard U, Manz M. Studies on the efficacy and prognostic significance of drug therapy of ventricular tachyarrhythmias. Herz 1997; 22 Suppl 1:1-2. [PMID: 9259190 DOI: 10.1007/bf03044566] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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87
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Beanlands RS, deKemp R, Scheffel A, Nahmias C, Garnett ES, Coates G, Johansen HL, Fallen E. Can nitrogen-13 ammonia kinetic modeling define myocardial viability independent of fluorine-18 fluorodeoxyglucose? J Am Coll Cardiol 1997; 29:537-43. [PMID: 9060890 DOI: 10.1016/s0735-1097(96)00561-x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
OBJECTIVES The hypothesis of this study was that evaluation of myocardial flow and metabolism using nitrogen-13 (N-13) ammonia kinetic modeling with dynamic positron emission tomographic (PET) imaging could identify regions of myocardial scar and viable myocardium as defined by fluorine-18 fluorodeoxyglucose (F-18 FDG) PET. BACKGROUND Uptake of most perfusion tracers depends on both perfusion and metabolic retention in tissue. This characteristic has limited their ability to differentiate myocardial scar from viable tissue. The kinetic modeling of N-13 ammonia permits quantification of blood flow and separation of the metabolic component of its uptake, which may permit differentiation of scar from viable tissue. METHODS Sixteen patients, > 3 months after myocardial infarction, underwent dynamic N-13 ammonia and F-18 FDG PET imaging. Regions of reduced and normal perfusion were defined on static N-13 ammonia images. Patients were classified into two groups (group I [ischemic viable], n = 6; group II [scar], n = 10) on the basis of percent of maximal F-18 FDG uptake in hypoperfused segments. Nitrogen-13 ammonia kinetic modeling was applied to dynamic PET data, and rate constants were determined. Flow was defined by K1; volume of distribution (VD = K1/k2) of N-13 ammonia was used as an indirect indication of metabolic retention. RESULTS Fluorine-18 FDG uptake was reduced in patients with scar compared with normal patients with ischemic viable zones (ischemic viable 93 +/- 27% [mean +/- SD]; scar 37 +/- 16%, p < or = 0.01). Using N-13 ammonia kinetic modeling, flow and VD were reduced in the hypoperfused regions of patients with scar (ischemic viable flow: 0.65 +/- 0.20 ml/min per g, scar: 0.36 +/- 0.16 ml/min per g, p < or = 0.01; VD: 3.9 +/- 1.3 and 2.0 +/- 1.07 ml/g, respectively, p < or = 0.01). For detection of viable myocardium in these patients, the sensitivity and specificity were 100% and 80% for N-13 ammonia PET flow > 0.45 ml/min per g; 100% and 70% for VD > 2.0 ml/g; and 100% and 90% for both flow > 0.45 ml/min per g and VD > 2.0 ml/g, respectively. The positive and negative predictive values for the latter approach were 86% and 100%, respectively. CONCLUSIONS In this cohort, patients having regions with flow < or = 0.45 ml/min per g or VD < or = 2.0 ml/g had scar. Viable myocardium had both flow > 0.45 ml/min per g and VD > 2.0 ml/g. Nitrogen-13 ammonia kinetic modeling permits determination of blood flow and metabolic integrity in patients with previous myocardial infarction and can help differentiate between scar and ischemic but viable myocardium.
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Affiliation(s)
- R S Beanlands
- Division of Cardiology, E. S. Garnett Medical Imaging Research Centre, McMaster University Medical Centre, Ottawa, Ontario, Canada
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