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Progress in Cardiovascular Diseases 1987Infarct expansion and infarct extension are events early in the course of myocardial infarction with serious short- and long-term consequences. Infarct expansion,... (Clinical Trial)
Clinical Trial Review
Infarct expansion and infarct extension are events early in the course of myocardial infarction with serious short- and long-term consequences. Infarct expansion, disproportionate thinning, and dilatation of the infarct segment probably begin within hours of acute infarction and usually reach peak extent within seven to 14 days. Clinical data suggest that infarct expansion occurs in approximately 35% to 45% of anterior transmural myocardial infarctions and to a lesser extent in infarctions at other sites. Although expansion usually develops in large infarcts, the extent of transmural necrosis rather than absolute infarct size predicts its occurrence. Expansion has an adverse effect on infarct structure and function for several reasons. Functional infarct size is increased because of infarct segment lengthening, and expansion results in over-all ventricular dilatation. Thus, patients with expansion of an infarct have poorer exercise tolerance, more congestive heart failure symptoms, and greater early and late mortality than those without expansion. Infarct rupture and late aneurysm formation are two additional structural consequences of infarct expansion. Experimental and clinical data suggest that the incidence and severity of expansion can be modified by interventions. Increased ventricular loading conditions and steroidal and nonsteroidal antiinflammatory agents make expansion more severe. Reperfusion of the infarct segment and pharmacologic interventions that decrease ventricular afterload lessen the severity of expansion. Previous myocardial infarction and preexisting ventricular hypertrophy may also limit the development of infarct expansion. Infarct extension is defined clinically as early in-hospital reinfarction after a myocardial infarction. The pathologic finding of infarct extension is necrotic and healing myocardium of several different recent ages within the same vascular territory. Although this pathologic criterion usually cannot be verified, studies employing invasive and noninvasive assessment of patients with early reinfarction provide evidence that the new myocardial injury is usually in the same vascular risk region as the original infarction. A variety of different criteria have been applied in the clinical diagnosis of infarct extension, and this has resulted in a large range of estimated frequencies from under 10% to as high as 86%. High estimates are found in studies using one or two nonspecific criteria such as ST segment shift or reelevation of total CK. The lowest rates have been found when combinations of criteria are used.(ABSTRACT TRUNCATED AT 400 WORDS)
Topics: Adrenergic beta-Antagonists; Anticholesteremic Agents; Anticoagulants; Aspirin; Cholesterol; Clinical Trials as Topic; Coronary Artery Bypass; Dipyridamole; Heart; Humans; Myocardial Infarction; Myocardium; Prognosis; Recurrence; Sulfinpyrazone
PubMed: 2888158
DOI: 10.1016/0033-0620(87)90004-1 -
The American Journal of Cardiology Nov 1991Infarct expansion can be defined pathologically as a distortion of ventricular topography produced by thinning and disproportionate dilation of the infarct segment.... (Review)
Review
Infarct expansion can be defined pathologically as a distortion of ventricular topography produced by thinning and disproportionate dilation of the infarct segment. Large transmural infarcts tend to be associated with greater propensity for infarct expansion. Two-dimensional echocardiography has made it feasible to detect these acute alterations in cardiac topography by serial examination of patients with acute myocardial infarction. A practical approach to the echocardiographic quantification of expansion involves analysis of end-diastolic cross-sectional echo views at the papillary muscle level, which can be used as fixed internal landmarks to divide the left ventricle into 2 segments, anterior and posterior. An off-line computer system can be used to track relative lengths of these segments as well as their thicknesses over time. In the initial clinical study, one third of patients with acute anterior transmural infarcts showed an average 50% increase in the infarct segment length beginning within the first 3 days of infarction, characterized by disproportionate progressive dilation and transmural thinning of this zone. These patients demonstrated a significantly higher mortality than those without expansion. Later studies demonstrated not only continuing dilation of the infarcted anterior wall, but also progressive dilation of the noninfarcted posterior wall, underscoring the importance of continuing long-term noninvasive follow-up. Not only is expansion associated with a poor clinical outcome; it has also been shown experimentally and clinically to be modifiable or even preventable by various therapeutic maneuvers, which may well improve survival. Because of the limitations of the echocardiographic window, it is often possible to obtain only a single cross-sectional view of high quality, and even then technical quality may not be sufficiently high to enable detailed quantitative analysis.(ABSTRACT TRUNCATED AT 250 WORDS)
Topics: Animals; Cardiomegaly; Humans; Myocardial Infarction; Myocardium
PubMed: 1836095
DOI: 10.1016/0002-9149(91)90259-n -
Archives of Pathology & Laboratory... May 1980Because patient prognosis is related in part to infarct size, therapies that could limit infarct size should be beneficial. The development of such therapies has been... (Review)
Review
Because patient prognosis is related in part to infarct size, therapies that could limit infarct size should be beneficial. The development of such therapies has been hampered by the lack of proven techniques to measure infarct size or to assess the effect of therapy in living patients. In addition, the evolution of ischemic cell death in human infarcts is not understood, and therefore the amount of ischemic myocardium that might be salvageable at various times after the onset of myocardial infarction is unknown. Experimental studies have contributed to our understanding of the evolution of acute myocardial infarcts. However, there is a continuing need for experimental and human anatomical studies to validate indirect in vivo techniques of estimating infarct size. In addition, reliable experimental models in which potential therapies can be tested are needed. In dogs, infarct size is predetermined in part by the amount of myocardium at risk and the amount of collateral flow in this risk region. Measuring these parameters should provide a framework within which the effects of therapy on infarct size can be assessed.
Topics: Animals; Arrhythmias, Cardiac; Cardiomegaly; Cell Survival; Collateral Circulation; Coronary Vessels; Creatine Kinase; Dogs; Dye Dilution Technique; Electrocardiography; Histological Techniques; Humans; Isoenzymes; Methods; Myocardial Infarction; Myocardium; Myoglobin; Oxygen Consumption; Prognosis; Risk; Shock, Cardiogenic; Time Factors
PubMed: 6445181
DOI: No ID Found -
Journal of Neuroimaging : Official... Jul 2018The thalamus is a part of the diencephalon, containing numerous connections between the forebrain and subcortical structures. It serves an important function as a relay... (Review)
Review
The thalamus is a part of the diencephalon, containing numerous connections between the forebrain and subcortical structures. It serves an important function as a relay center between the cerebral cortex and the subcortical regions, particularly with sensory information. The thalamus also plays a major role in regulating arousal and the levels of awareness. Distinct vascular distribution of the thalamus give rises to different syndromic presentation of thalamic nuclei infarcts. The clinical records and available imaging studies of patients with confirmed thalamic territory infarcts on magnetic resonance imaging (MRI) at the University Hospital of Rochester were reviewed and analyzed. This analysis was then used to provide an effective summary of thalamic vascular anatomy, the clinical symptoms, and syndromes associated with strokes in the affected territories. Specifically, we review the syndromes associated with classic vascular territories, including the anterior, paramedian, inferolateral, and posterior thalamic nuclei, that are supplied by the polar (tuberothalamic), paramedian, inferolateral (thalamogeniculate), and posterior choroidal arteries, respectively. In addition, we will also review the variant thalamic territories and associated infarction syndromes of the anteromedian, central, and posterolateral territories. This review article is aimed to better the clinical and radiologic understanding as well as the diagnosis of classic and variant thalamic territory infarcts. This article will also briefly touch on the recovery of function after thalamic infarcts.
Topics: Brain Infarction; Humans; Magnetic Resonance Imaging; Neuroimaging; Risk Factors; Stroke; Thalamic Diseases; Thalamus
PubMed: 29460331
DOI: 10.1111/jon.12503 -
Journal of Stroke and Cerebrovascular... Oct 2018Spinal cord infarction is an uncommon disease varying in its clinical presentation. This study describes the clinical and radiological presentation of spinal cord... (Observational Study)
Observational Study
INTRODUCTION
Spinal cord infarction is an uncommon disease varying in its clinical presentation. This study describes the clinical and radiological presentation of spinal cord infarcts in 17 consecutive patients.
MATERIAL AND METHODS
Clinical and MR imaging data of 17 patients were reviewed. Inclusion criteria were acute or subacute presentation (peak within 72 hours) and MRI showing typical signal changes on T2WI compatible with spinal cord infarct. Exclusion criteria were clinical or MRI findings suggesting other etiologies.
RESULTS
Clinical presentation included dissociative anesthesia, weakness of limbs, back or neck pain, and autonomic symptoms with symptom onset to peak time ranging from few minutes to 48 hours in patients with anterior spinal artery infarct (n = 16), and weakness and sensory loss in ipsilateral upper limb in patient with posterior spinal artery infarct (n = 1). One patient presented with "man-in-the-barrel syndrome (MIB)." MRI findings in anterior spinal artery infarcts included pencillike hyperintensities on T2 sagittal (n = 16, 100%) and "owl eye" appearance on T2 axial (n = 6, 37.5%) images. Diffusion restriction was noted in 8 cases and enhancement was noted in 2 cases. The posterior spinal artery infarct showed T2 hyperintensity in left posterior paramedian triangular distribution in cervical cord (C2-C7). Follow-up was available for 9 patients (period ranging from 15-41 months). Four patients had a favorable outcome who could walk independently, 1 patient could walk with support, and 2 patients were wheelchair bound. Two patients died.
CONCLUSION
Spinal cord infarction is a rare but important cause of acute spinal syndrome. Typical distribution and appropriate imaging can help in timely diagnosis.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Child; Dependent Ambulation; Diffusion Magnetic Resonance Imaging; Disability Evaluation; Female; Humans; Infarction; Male; Middle Aged; Mobility Limitation; Predictive Value of Tests; Recovery of Function; Retrospective Studies; Risk Factors; Spinal Cord; Spinal Cord Ischemia; Time Factors; Treatment Outcome; Walking; Wheelchairs; Young Adult
PubMed: 30093205
DOI: 10.1016/j.jstrokecerebrovasdis.2018.06.008 -
Basic Research in Cardiology Nov 2008This review takes a critical look at the current effectiveness of reperfusion therapy for acute myocardial infarction and at the potential for cardioprotective agents to... (Review)
Review
This review takes a critical look at the current effectiveness of reperfusion therapy for acute myocardial infarction and at the potential for cardioprotective agents to improve it. Reperfusion alone limits the median value of infarct size to approximately 50% of the ischemic region. However, the range of infarct sizes is very wide, and one-fourth of these patients have more than 75% of the ischemic zone infarcted despite successful coronary reperfusion. Available studies suggest that mortality and morbidity is increased when more than 20% of the left ventricle is infarcted. Therefore, to be effective infarct size-limiting therapy would have to reduce infarction to or below this 20% target. To achieve this goal in the quartile of patients with the biggest infarcts the cardioprotective agent would have to be potent enough to reduce infarct size from its current value of 75% of the ischemic zone to 40% or less. While ischemic preconditioning and some pretreatment drugs might be potent enough to achieve this goal, few of the agents given at the clinically relevant time of at or just before reperfusion have exhibited such potency. Several cardioprotective agents have recently been evaluated in clinical trials but their results have been disappointing. Some of the poor clinical trial performance may stem from study designs which fail to identify those patients falling within the upper quartile of infarct sizes, presumably the only group that would be expected to actually benefit from a reduction in infarct size. Other possible causes could be that co-morbidities or drugs patients are taking may block the pathways involved in the anti-infarct effect or that the drugs simply do not protect even in animal models. Few agents have been thoroughly tested in clinically relevant animal models prior to their testing in man.
Topics: Animals; Cardiotonic Agents; Disease Models, Animal; Humans; Myocardial Infarction; Myocardial Reperfusion; Signal Transduction; Treatment Outcome
PubMed: 18716709
DOI: 10.1007/s00395-008-0743-y -
The Canadian Journal of Neurological... Sep 2019Brain neoplasms are the second-most prevalent cancer of childhood for which surgical resection remains the main treatment. Intraoperative MRI is a useful tool to...
BACKGROUND
Brain neoplasms are the second-most prevalent cancer of childhood for which surgical resection remains the main treatment. Intraoperative MRI is a useful tool to optimize brain tumor resection. It is, however, not known whether intraoperative MRI can detect complications such as hyperacute ischemic infarcts.
METHODS
A retrospective analysis of pre- and intraoperative MRIs including DWI sequence and correlation with early and 3-month postoperative MRIs was conducted to evaluate the incidence of hyperacute arterial infarct during pediatric brain tumor resection. Patient demographics, pathological type, tumor location, resection type as well as preoperative tumoral vessel encasement, evolution of the area of restricted diffusion were collected and analyzed comparatively between the group with acute infarct and the control group. Extent of the hyperacute infarct was compared to both early postsurgical and 3-month follow-up MRIs.
RESULTS
Of the 115 cases, 13 (11%) developed a hyperacute arterial ischemic infarct during brain tumor resection. Tumoral encasement of vessels was more frequent in the infarct group (69%) compared to 25.5% in the control group. Four cases showed additional vessel irregularities on intraoperative MRI. On early follow-up, the infarcted brain area had further progressed in six cases and was stable in seven cases. No further progression was noted after the first week post-surgery.
CONCLUSIONS
Hyperacute infarcts are not rare events to complicate pediatric brain tumor resection. Tumoral encasement of the circle of Willis vessels appears to be the main risk factor. Intraoperative DWI underestimates the final extent of infarcted tissue compared to early postsurgical MRI.
Topics: Brain Infarction; Brain Neoplasms; Child; Child, Preschool; Diffusion Magnetic Resonance Imaging; Female; Humans; Incidence; Intraoperative Complications; Intraoperative Period; Male; Neurosurgical Procedures; Retrospective Studies
PubMed: 31179961
DOI: 10.1017/cjn.2019.226 -
Topics in Magnetic Resonance Imaging :... Dec 2000Magnetic resonance imaging offers the unique opportunity to directly visualize the size and location of myocardial infarcts (MIs) with excellent spatial resolution.... (Comparative Study)
Comparative Study Review
Magnetic resonance imaging offers the unique opportunity to directly visualize the size and location of myocardial infarcts (MIs) with excellent spatial resolution. Because infarct size is the most important determinant of postinfarct outcome, precise determination of infarct size may be valuable to risk stratify patients after acute MI. In addition, infarct imaging may provide direct information on the amount of irreversibly injured myocardium and thus can be used to identify myocardial viability in dysfunctional regions. Acute infarcts can be recognized as hyperintense signal on T2-weighted spin-echo images. This technique, however, does not identify chronic infarcts and may overestimate infarct size by including area at risk. Also, T2-weighted images often have a low signal-to-noise ratio. Contrast-enhanced perfusion imaging provides better-quality images. Extravascular contrast agents such as (Gd-DTPA) gadolinium diethyletriamine-pentaacetic acid identify infarcts as hyperenhanced regions on images acquired late after contrast injection. In addition, these tracers can examine the integrity and permeability of infarct microvasculature on first-pass perfusion images. Necrosis avid tracers and 23Na imaging are other new exciting approaches to identify infarcted myocardium acutely after MI. These techniques, are still investigational, and their value for clinical imaging remains to be established.
Topics: Contrast Media; Female; Gadolinium DTPA; Humans; Magnetic Resonance Imaging; Male; Myocardial Infarction; Radiographic Image Enhancement; Sensitivity and Specificity
PubMed: 11153704
DOI: 10.1097/00002142-200012000-00006 -
Practical Neurology Oct 2023
Topics: Humans; Infarction; Brain Stem Infarctions; Medulla Oblongata; Magnetic Resonance Imaging
PubMed: 37147121
DOI: 10.1136/pn-2023-003732 -
Der Nervenarzt Aug 1990Our pathogenetically oriented classification system of hemispheric brain infarctions is reviewed. New data are presented to validate this classification from various... (Review)
Review
Our pathogenetically oriented classification system of hemispheric brain infarctions is reviewed. New data are presented to validate this classification from various points of view. A retrospective analysis of 73 patients with large striato-capsular infarcts demonstrated that two-thirds of them had a source of embolism either in the carotid bifurcation or in the heart. SPECT-imaging in patients with hemispheric brain infarctions of various origin revealed that the area of exhausted cerebral perfusion reserve largely exceeds the area of the infarct visible on CT if a hemodynamically caused low-flow infarction is present. This is not the case in the territorial type. Measurement of the hemispheric vasomotor reactivity to capnic stimuli confirmed this finding by demonstrating a severely reduced VMR in low-flow infarctions, but not in thrombo-embolically caused territorial infarctions. Lacunar infarctions due to occlusion of single long penetrating arteries should be judged as either "unequivocal", "probable" or "possible lacunae" and should be differentiated from small lacunar-like infarctions in the cortex ("non-lacunae") which represent small territorial infarctions due to thromboembolism of small pial arteries. Infarctions in the temporo-parieto-occipital watershed area are difficult to distinguish from territorial infarctions within the posterior part of the middle cerebral artery distribution. For research purposes, such patients should be excluded in order to keep the subgroups homogeneous. Consequences of this classification system for diagnostic and therapeutic strategies in stroke patients are discussed.
Topics: Blood Flow Velocity; Cerebral Infarction; Cerebrovascular Circulation; Humans; Regional Blood Flow; Tomography, X-Ray Computed
PubMed: 2234222
DOI: No ID Found