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PubMed1993

Effects of coronary blood flow on myocardial grey level amplitude in two dimensional echocardiography: an experimental study.

OBJECTIVE: The aims were: (1) to evaluate whether differences in absolute and cyclic echocardiographic image amplitude exist in different layers (subendocardium and subepicardium) and regions (septal, anterior, lateral, inferior wall) of the canine left ventricle; (2) to assess the dependence of these variables upon local variations of coronary blood flow. METHODS: In six anaesthetised open chest dogs the circumflex coronary artery was cannulated and perfused by a roller pump with blood from their own femoral artery. Maximum coronary vasodilatation was obtained by continuous adenosine infusion. The absolute values and the transmural distribution of coronary blood flow were measured by radionuclide labelled microspheres. Echo images were obtained in short axis view by a commercially available electronic sector scanner with a 5.0 MHz transducer directly placed on the epicardial surface of the right ventricle, and digitised off-line into a matrix of 256 x 256 pixels with 25% grey level per pixel. The average grey level was calculated for each region of interest. RESULTS: In 32 different conditions, circumflex flow ranged from 0.80 to 12.89 ml.min-1.g-1 and the endocardial/epicardial ratio of flow from 0.53 to 1.73. In the circumflex region (subjected to flow changes) segmental amplitude varied from 76(SD 20) (end diastole) to 56(18) (end systole), p < 0.001. In all regions, a consistent cyclic variation was found, ranging from 9(14) to 28(16)%. For all levels of flow, subendocardial and subepicardial regions showed similar values of both absolute amplitude and cyclic variation. No significant relationship was found between transmural distribution of blood flow and either segmental amplitude (r = 0.26) or cyclic variation (r = 0.04). CONCLUSIONS: (1) a consistent cyclic grey level variation is present in all regions of the canine left ventricle, but subendocardial and subepicardial layers show similar values of both absolute amplitude and cyclic variation; (2) in the absence of severe underperfusion and echocardiographically detectable dyssynergy, absolute amplitude and cyclic variation are totally unrelated to changes in coronary blood flow.

Animals↗

PubMed1989

Quantitation of myocardial perfusion by contrast echocardiography: analysis of contrast gray level appearance variables and intracyclic variability.

Hand-agitated diatrizoate meglumine/diatrizoate sodium (MD-76) was injected above the aortic valve in seven dogs during two-dimensional echocardiographic imaging to determine the ability of contrast appearance variables (i.e., peak background-subtracted gray level intensity, time to peak contrast appearance and maximal slope of the contrast appearance curve) to predict myocardial blood flow. Regional perfusion was altered by a critical coronary stenosis (around the left anterior descending coronary artery) or by administering intracoronary adenosine (into the left circumflex coronary artery), or both. Changes in regional blood flow between control and interventions were compared with the changes in the contrast appearance variables. In addition, the ability of intracyclic variability of gray level intensity to predict myocardial perfusion was assessed. In the determination of absolute myocardial perfusion, background-subtracted peak gray level intensity and the maximal slope of the appearance curve demonstrated a fair correlation (r = 0.67 and 0.51, respectively, p less than 0.0001). However, time to peak contrast appearance did not correlate (r = 0.14, p = 0.31). Intracyclic variability of gray level intensity at control (before contrast injection) and after contrast injection also did not correlate with perfusion (r = 0.18 and 0.06, respectively). In the evaluation of relative changes in myocardial blood flow, the percent change in the maximal slope of the appearance curve correlated with the percent change in blood flow (r = 0.77, p less than 0.0001). Seven of the eight regions with greater than 3.5-fold increase in blood flow were identified by an increase in maximal slope of greater than 50%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

Maldistribution of heterogeneous coronary blood flow during canine endotoxin shock.

STUDY OBJECTIVE - The aim was to investigate whether heterogeneous coronary blood flow is maldistributed during endotoxin shock. DESIGN - Variables were studied before (t = 0) and at t = 90 and t = 120 min after bolus injection of saline (n = 6) or endotoxin (n = 6). SUBJECTS - 12 anaesthetised mongrel dogs, weight 20-27 kg, were used. MEASUREMENTS AND MAIN RESULTS - We studied myocardial blood flows in small tissue sections (of about 1 g in left and 2 g in right ventricle) with radioactive microspheres, together with haemodynamic variables and global myocardial metabolism. At t = 0 min in controls, regional flows per 100 g were heterogeneous and ranged from a factor 0.2 to 2.7 and 0.6 to 1.6 of mean flow per 100 g to the left and right ventricle respectively; heterogeneity was unchanged at t = 90 and t = 120 min. Between t = 0, t = 90, and t = 120 min regional flows correlated: r = 0.78(SD 0.14), n = 18, for left ventricle, and r = 0.70(0.17) for right ventricle. In the endotoxin group, cardiac output and mean arterial pressure decreased by 44(7) and 48(11)% respectively, and lactate increased by 3.2(0.6) mmol.litre-1 at t = 120 min. Global left ventricle blood flow and delivery and metabolism of O2 were unchanged; lactate extraction and external work fell. The ratio between global right ventricular O2 delivery and external work also rose. Regional blood flows ranged from a factor 0.2 to 2.7 and 0.1 to 1.8 of mean flow to left and right ventricles respectively; heterogeneity did not differ from controls and did not change with time. Flow correlations with time were reduced: 0.45(0.24) for left ventricle and 0.45(0.26) for right ventricle (both n = 18, p less than 0.005 v controls). The left ventricular endocardial to epicardial flow ratio fell; flow was redistributed to both layers. CONCLUSIONS - Heterogeneous blood flow is redistributed throughout the heart during canine endotoxin shock so that, at unchanged global blood flow and flow heterogeneity, flow decreases in some but increases in other areas. Flow maldistribution may be associated with focal ischaemia, which may be masked by a rise in O2 uptake for a given workload (contractile inefficiency) in overperfused areas, and may thereby contribute to a fall in global myocardial external work for a given O2 delivery.

Animals↗

PubMed1998

Positive inotropy due to lowering cyclic GMP is also mediated by increases in cyclic AMP in control and hypertrophic hearts.

The aim of the current study was to determine if lowering myocardial cyclic GMP by guanylate cyclase inhibition would add independently to the positive inotropic effects caused by raising cyclic AMP and if these effects are modified in left ventricular hypertrophy (LVH) produced by aortic valve plication. Isoproterenol (ISO) (0.1 mg x kg(-1) x min(-1)) was infused into a branch of the left anterior descending coronary artery of seven control and eight hypertrophy open-chest anesthetized dogs. After 10 min, simultaneous infusion of methylene blue (MB) (2 mg x kg(-1) x min(-1)) was initiated at the same site. Hypertrophy increased heart weight and heart weight/body weight ratio. While both drugs increased left ventricular dP/dt(max), no additional global effects were observed in either group. Changes in regional variables followed the same pattern in both groups, i.e., ISO produced an increase that was enhanced by the addition of MB. ISO increased segment shortening, with a significant change in the control group. ISO increased regional force in both groups. The addition of MB increased force above ISO levels, with a significant change in the LVH group. ISO increased regional minute work (g x mm x min(-1)) (control, 1779 +/- 428 to 2541 +/- 500; LVH, 1157 +/- 253 to 1839 +/- 404) and O2 consumption. MB further increased regional work (control, 2993 +/- 952; LVH, 2416 +/- 853) and O2 consumption. ISO raised cyclic AMP (pmoles x g(-1)) (control, 468 +/- 41 to 580 +/- 84; LVH, 445 +/- 43 to 562 +/- 71) and had no effect on cyclic GMP (pmoles x g(-1)) (control, baseline 3.27 +/- 0.22, ISO 2.87 +/- 0.23; LVH, baseline 6.84 +/- 1.12, ISO 5.66 +/- 0.54). The addition of MB lowered cyclic GMP (control, 2.41 +/- 0.26; LVH, 3.68 +/- 0.35), but also increased cyclic AMP (control, 1021 +/- 121; LVH, 1107 +/- 134). Similar results were observed in control hearts using a specific soluble guanylate cyclase inhibitor (ODQ) in terms of changes in local work, O2 consumption, and cyclic nucleotides. Thus, at least part of the positive inotropic response to lowering cyclic GMP was mediated by changes in cyclic AMP in the current model. This was true in both control and LVH animals, although baseline cyclic GMP levels were higher, and a larger reduction in cyclic GMP was observed with MB in the LVH group.

Animals↗

PubMed2002

Quantification of myocardial hypoperfusion with 99m Tc-sestamibi in patients undergoing prolonged coronary artery balloon occlusion.

Percutaneous transluminal coronary angioplasty provides an excellent opportunity to investigate the location and quantity of hypoperfusion during sudden complete occlusion of one of the major coronary arteries. Thirty-five patients referred for elective percutaneous transluminal coronary angioplasty were injected intravenously with 99mTc-sestamibi during balloon inflation. To visualize and quantify the hypoperfused region, a map of perfusion was constructed from that occlusion study and from the control study performed on the following day. Patients were divided into groups according to proximal or distal occlusion within each of the three coronary arteries. The region of myocardium supplied by each coronary artery varied in location and extended outside the typical borders for all arteries, but most prominently for the left circumflex coronary artery. The quantities of hypoperfusion varied within each artery group, but the average hypoperfusion was greater for the left anterior descending coronary artery than for either the right coronary artery or the left circumflex coronary artery. It is concluded that the quantities of hypoperfusion were highly variable within each artery group. Occlusion of the left anterior descending coronary artery was associated with the largest ischaemic region. The area of hypoperfusion extended outside the typical borders, most prominently for the left circumflex coronary artery.

Adult↗

PubMed2001

Cortical change in Alzheimer's disease detected with a disease-specific population-based brain atlas.

We report the first detailed population-based maps of cortical gray matter loss in Alzheimer's disease (AD), revealing prominent features of early structural change. New computational approaches were used to: (i) distinguish variations in gray matter distribution from variations in gyral patterns; (ii) encode these variations in a brain atlas (n = 46); (iii) create detailed maps localizing gray matter differences across groups. High resolution 3D magnetic resonance imaging (MRI) volumes were acquired from 26 subjects with mild to moderate AD (age 75.8+/-1.7 years, MMSE score 20.0+/-0.9) and 20 normal elderly controls (72.4+/-1.3 years) matched for age, sex, handedness and educational level. Image data were aligned into a standardized coordinate space specifically developed for an elderly population. Eighty-four anatomical models per brain, based on parametric surface meshes, were created for all 46 subjects. Structures modeled included: cortical surfaces, all major superficial and deep cortical sulci, callosal and hippocampal surfaces, 14 ventricular regions and 36 gyral boundaries. An elastic warping approach, driven by anatomical features, was then used to measure gyral pattern variations. Measures of gray matter distribution were made in corresponding regions of cortex across all 46 subjects. Statistical variations in cortical patterning, asymmetry, gray matter distribution and average gray matter loss were then encoded locally across the cortex. Maps of group differences were generated. Average maps revealed complex profiles of gray matter loss in disease. Greatest deficits (20-30% loss, P<0.001-0.0001) were mapped in the temporo-parietal cortices. The sensorimotor and occipital cortices were comparatively spared (0-5% loss, P>0.05). Gray matter loss was greater in the left hemisphere, with different patterns in the heteromodal and idiotypic cortex. Gyral pattern variability also differed in cortical regions appearing at different embryonic phases. 3D mapping revealed profiles of structural deficits consistent with the cognitive, metabolic and histological changes in early AD. These deficits can therefore be (i) charted in a living population and (ii) compared across individuals and groups, facilitating longitudinal, genetic and interventional studies of dementia.

Aged↗

PubMed2000

Cortical activity related to accuracy of letter recognition.

Previous imaging and neurophysiological studies have suggested that the posterior inferior temporal region participates in tasks requiring the recognition of objects, including faces, words, and letters; however, the relationship between accuracy of recognition and activity in that region has not been systematically investigated. In this study, positron emission tomography was used to estimate glucose metabolism in 60 normal adults performing a computer-generated letter-recognition task. Both a region of interest and a voxel-based method of analysis, with subject state and trait variables statistically controlled, found task accuracy to be: (1) negatively related to metabolism in the left ventrolateral inferior temporal occipital cortex (Brodmann's area 37, or ventrolateral BA 37) and (2) positively related to metabolism in a region of the right ventrolateral frontal cortex (Brodmann's areas 47 and 11, or right BA 47/11). Left ventrolateral BA 37 was significantly related both to hits and to false alarms, whereas the right BA 47/11 finding was related only to false alarms. The results were taken as supporting an automaticity mechanism for left ventrolateral BA 37, whereby task accuracy was associated with automatic letter recognition and in turn to reduced metabolism in this extrastriate area. The right BA 47/11 finding was interpreted as reflecting a separate component of task accuracy, associated with selectivity of attention broadly and with inhibition of erroneous responding in particular. The findings are interpreted as supporting the need for control of variance due to subject and task variables, not only in correlational but also in subtraction designs.

Adult↗

PubMed2000

Field-by-field evaluation of intraoperative transoesophageal echocardiography interpretative skills.

A quality assurance system is essential for the credibility and structured growth of anaesthesiology-based transoesophageal echocardiography (TEE) programmes. We have developed software (Q/A Kappa), involving a 400-line source code, capable of directly reporting kappa correlation coefficient values, using external reviewer interpretations as the 'gold standard', and thereby allowing systematic assessment of the validity of intraoperative echocardiographic interpretation. This paper presents assessment of the validity of 240 intraoperative anaesthesiologists' echocardiographic interpretations, and, in addition, the results of field testing of this prototypical software. Data, derived from consecutive cardiac surgery patients, consisted of standardized two-dimensional transoesophageal echocardiographic, colour flow and Doppler imaging sequences. Intraoperative and off-line 'gold standard' TEE interpretations were compared for 19 fields or variables using the Q/A Kappa program. The kappa correlation coefficients were highly variable and dependent on the examination field, ranging from 0.08 for apical regional wall motion scores to 1.00 for tricuspid regurgitation grade, left atrial measurement, aortic valve anatomy and left ventricular long axis and short axis global function. The correlation coefficients were also operator dependent. These data (480 interpretations) were also manually integrated into the equation required for calculation of values of the variable kappa correlation coefficient. The relationship between Q/A Kappa-derived values and manually calculated values was highly significant (p < 0.001; r = 1.0). The implications and possible explanations of the results for particular examination fields are discussed. This study also demonstrates successful seamless functioning of this software program from data entry, segmentation into tables and valid statistical analysis. These findings suggest that it is practical to provide sophisticated continuous quality improvement TEE data on a routine basis.

Adult↗

PubMed1991

Revascularization of infarcted vs. viable myocardium. Effects on symptoms, physical performance and global/regional left ventricular function.

Symptoms, physical performance and global vs. regional left ventricular (LV) function were reviewed in 25 patients with postinfarction anterior-apical akinesia and minor dyskinesia who subsequently underwent revascularization of all graftable stenotic vessels. The observed postoperative improvement in functional NYHA capacity and physical performance was not related to significant change in any systolic or diastolic variable of global LV function. 'Nonspecific postoperative septal hypokinesia' developed in most cases. The regional ejection fraction showed slight (nonsignificant) mean increase in the infarcted apex and low anterior wall supplied by the left anterior descending artery, but marked increase in the noninfarcted lateral wall supplied by the left circumflex branch. Hearts with grafted left circumflex artery showed on average lower preoperative and postoperative ejection fraction in the lateral wall than did hearts without such grafting, but the rise in regional ejection fraction was significant only after left circumflex grafting. The clinical response to coronary artery surgery is attributed mainly to functional improvement of non-infarcted myocardium. Revascularization of viable myocardium occurs directly via bypass grafts, but collateral vessels may also contribute.

Adult↗

PubMed2003

Electrical heterogeneity and arrhythmogenesis: importance of conduction velocity dispersion.

An experimental model of conduction velocity (CV) and refractory period dispersion was established to determine which variable is a determinant of myocardial vulnerability. Anesthetized swine were instrumented with a left anterior descending coronary artery catheter for regional infusion of lidocaine (n = 6), low-dose d-sotalol (n = 4), high-dose d-sotalol (n = 6), or saline (n = 6), to create dispersion in CV (lidocaine), refractoriness (d-sotalol), or neither (saline). Ventricular fibrillation thresholds (VFTs) and refractory periods were determined at five sites (one drug perfused, four non-drug perfused). CV was determined in one drug-perfused area (left ventricular epicardial apex) and one non-drug perfused area (right ventricular epicardial base). Lidocaine and low- and high-dose d-sotalol increased VFT when stimuli were delivered in the drug-perfused area. However, lidocaine decreased VFT when stimuli were delivered at non-drug perfused areas by an average of 52%. Neither d-sotalol dose affected VFT when stimuli were delivered in non-drug perfused areas. Lidocaine increased CV dispersion by 18-26 cm/s but did not alter refractoriness. Both d-sotalol doses increased dispersion in refractoriness by 15-27 ms but did not alter CV. Saline did not affect either variable. Regional lidocaine had profibrillatory effects when stimuli were delivered in non-drug perfused areas, whereas regional d-sotalol did not. Hence, CV dispersion is a more likely determinant of myocardial vulnerability than refractoriness.

Animals↗

PubMed1998

Coronary blood flow dynamics during transcutaneous electrical nerve stimulation for stable angina pectoris associated with severe narrowing of one major coronary artery.

To study the effect of transcutaneous electrical nerve stimulation (TENS) on coronary vasomotion, patients with New York Heart Association class III angina pectoris and significant single-vessel left coronary artery disease and who were also scheduled for elective percutaneous transluminal coronary angioplasty, were allocated to a study group (precordial actual TENS, n = 10) and a control group (precordial simulated TENS, n = 5, and TENS on the back, n = 3). Coronary volumetric flow was assessed in the stenotic and nonstenotic coronary artery before and after neurostimulation. The diameter (in millimeters) of the stenotic coronary artery was reduced in the study group after actual TENS (from 2.73 +/- 0.55 by 0.12 +/- 0.11; p = 0.008). In the nonstenotic coronary artery, the diameter increased in the study group (from 2.64 +/- 0.43 by 0.24 +/- 0.15; p = 0.01). In both the stenotic and nonstenotic coronary arteries, no effect was shown on the average peak velocity (centimeters per second) in the study group. The coronary volumetric flow (milliliters per minute) was reduced in the stenotic artery of the study group (from 62 +/- 18 by 8 +/- 7; p = 0.007). In the nonstenotic coronary artery, volumetric flow increased in the study group (from 57 +/- 18 by 11 +/- 10; p = 0.007). In the control group, simulated TENS and TENS on the back had no effect on the diameter of the artery, average peak velocity, or volumetric flow. In addition, in all patients, TENS had no effect on the total volumetric flow of the left coronary artery and hemodynamic variables during the study period. This observation suggests that TENS modulates regional coronary vasomotion in patients with coronary artery disease.

Aged↗

PubMed2003

High-resolution time course of hemispheric dominance revealed by low-resolution electromagnetic tomography.

OBJECTIVE: Auditory event-related brain potentials (ERPs) were recorded during a lexical decision task in response to linguistic and non-linguistic stimuli, to assess the detailed time course of language processing in general, and hemispheric dominance in particular. METHODS: Young adults (n=17) were presented with pairs of auditory stimuli consisting of words, pseudowords and words played backwards in a lexical decision task. ERPs were recorded from 21 scalp electrodes. Current densities were calculated using low-resolution electromagnetic tomography (LORETA). Statistic non-parametric maps of activity were derived from the calculated current densities and the number of active brain voxels in the left and right hemispheres was compared throughout the processing of each stimulus. RESULTS: Our results show that hemispheric dominance is highly time dependent, alternating between the right and left hemispheres at different times, and that the right hemisphere's role in language processing follows a different time course for first and second language. The time course of hemispheric dominance for non-linguistic stimuli was highly variable. CONCLUSIONS: The time course of hemispheric dominance is dynamic, alternating between left and right homologous regions, with different time courses for different stimulus classes.

Acoustic Stimulation↗

PubMed1987

Gated thallium scintigraphy in patients with coronary artery disease: an improved planar imaging technique.

The use of thallium scanning in the assessment of myocardial perfusion is well established. However, myocardial contraction leads to significant blurring of standard static images. By using electrocardiographic gating and a high sensitivity collimator, multiple view gated scans can be acquired prior to thallium redistribution. Reporting of these images on cine loop display in 100 consecutive patients undergoing coronary arteriography and 14 volunteers results in improved visual assessment of regional myocardial perfusion (with reduced interobserver variability) and, in addition, yields useful and accurate information on left ventricular function. The combination of better assessment of perfusion and information on wall motion results in improved detection of patients with significant coronary disease with no loss of specificity when compared with static images. Predictive accuracy improves from 85% to 94% with gated imaging. Gated thallium scanning could be readily applied in most centres using thallium at no extra cost and with improved predictive accuracy in the non-invasive detection of significant coronary disease.

Coronary Disease↗

PubMed1996

Aneurysm of the left sinus of Valsalva. An unusual source of cerebral embolism.

BACKGROUND: Aneurysm of the ascending aorta is rarely reported as the source of emboli. We report a patient with a minor stroke in whom a saccular aneurysm of the left sinus of Valsalva was diagnosed as the presumed source of cerebral embolism. CASE DESCRIPTION: A 49-year-old right-handed woman presented 10 days after sudden onset of right-sided hemiparesis. Her history was uneventful apart from an acute inflammation of the subcutaneous tissue in the right leg 20 years earlier. A diastolic murmur was heard best over the third left intercostal space. Results of duplex ultrasound investigation of the cerebral vessels, chest x-ray, and electrocardiography and biochemical and hematological variables were normal. CT of the brain showed a small hypodense area in the left frontal region. Transthoracic and transesophageal echocardiography detected moderate aortic regurgitation and a saccular aneurysm originating from the left sinus of Valsalva. The aneurysm had calcified walls and contained thrombotic material. Surgical closure of the aneurysm with a pericardial patch was performed to prevent recurrent embolism and rupture. Coaptation of the aortic valves was achieved, and no residual aortic regurgitation could be detected. CONCLUSIONS: We conclude that an unruptured sinus of Valsalva aneurysm should be included in the list of sources of embolism. Transthoracic echocardiography establishes the diagnosis. Transesophageal echocardiography provides additional information about the origin and size of the aneurysm and presence of thrombotic material. Surgical closure of the aneurysm prevents rupture and recurrent embolism and possibly corrects aortic regurgitation.

Aortic Aneurysm, Thoracic↗

PubMedDate not supplied

Coronary artery stenosis controlled by distal perfusion pressure: description of the servo-system and time-dependent changes in regional myocardial blood flow.

An animal model for the induction of coronary artery stenosis is described. In this model the degree of stenosis, as induced with commercially available hydraulic occluders, can be easily controlled by keeping constant the mean perfusion pressure (pcor) distal to the site of stenosis. This pcor is the input signal for a servo-system feeding a motor-pump, which determines the degree of inflation of the cuff around the left anterior interventricular coronary artery (LAICA). In each experiment pcor did not vary more than 2 mm Hg from the preset value of about 25 mm Hg. In 60 anesthetized open-chest dogs the time course of standard hemodynamic variables and regional myocardial blood flow in the center of the underperfused area, using the radioactive microsphere technique, were determined. Within 1 min after induction of stenosis heart rate and end-diastolic left ventricular pressure (plved) increased (by 20 and 60%, respectively) and mean aortic pressure and dplv/dtmax decreased (by 10 and 25%, respectively). After the initial decrease median myocardial blood flow further decreased between 1 and 5 min of stenosis from 0.63 to 0.32 ml.min-1.g-1 in the outer layers (P less than 0.05) and from 0.26 to 0.15 ml.min-1.g-1 in the inner layers (P less than 0.05), despite constant hemodynamic conditions and pcor. Between 5 and 120 min of stenosis these values remained unchanged in the outer layers, but decreased further in the inner layers to 0.08 ml.min-1.g-1 (P less than 0.05). The accurate control of pcor, the reproducibility of the levels of residual blood flow and the ease of handling the stenosis system indicate that coronary artery stenosis controlled by perfusion pressure distal to the stenosis is a useful animal model to study events during regional myocardial ischemia. With the use of this model of low flow ischemia a biphasic increase of myocardial vascular resistance was observed, which is initiated during the first minutes of coronary artery stenosis.

Animals↗

PubMed1993

Thrombolytic therapy for women with myocardial infarction: is there a gender gap? Thrombolysis and Angioplasty in Myocardial Infarction Study Group.

OBJECTIVES: The goal of this study was to investigate whether female gender portends an adverse prognosis independent of the severity of the underlying disease after acute myocardial infarction treated by thrombolysis. A total of 348 women were compared with 1,271 men enrolled in the Thrombolysis and Angioplasty in Myocardial Infarction (TAMI) trials. BACKGROUND: The reasons for gender differences in the management and prognosis of acute coronary artery syndromes remain poorly defined. The extent to which gender itself explains observed differences in outcome and use of diagnostic procedures remains unclear because confounding factors have not been specified. METHODS: Patients < 76 years of age presenting within 6 h of onset of ischemic symptoms with electrocardiographic ST segment elevation and without contraindications to thrombolysis, previous infarction in the same distribution or cardiogenic shock were prospectively enrolled in Phases 1 to 3, 5 and 7 of the TAMI trials. All patients received recombinant tissue-type plasminogen activator, urokinase or a combination of both agents. Protocol-mandated cardiac catheterization was performed during the hospital period. Rescue coronary angioplasty was carried out for reperfusion failure at angiography 90 min after initiation of thrombolytic therapy. Coronary artery bypass grafting or coronary angioplasty was performed for clinical indications. RESULTS: Women were older than men (61.0 +/- 9.7 vs. 55.8 +/- 10.1 years, mean +/- SD) and had a higher incidence of many risk factors for adverse outcome after myocardial infarction. There were no differences in baseline hemodynamic variables or time to thrombolytic treatment. Rates of acute and predischarge infarct-related artery patency and global and regional left ventricular function were similar in the two groups. Rates of in-hospital coronary angioplasty (52.6% and 54.1%) and bypass graft surgery (20.4% and 22.0%) were comparable in women and men, respectively. Women had higher unadjusted rates of mortality (9.2% vs. 5.4%, p = 0.014), reinfarction (6.4% vs. 2.6%, p = 0.005) and hemorrhagic stroke (2.0% vs. 0.55%, p = 0.017) than did men during the hospital period. When adjusted for clinical and angiographic variables, differences in mortality and hemorrhagic stroke did not reach statistical significance, and the risk of reinfarction was only marginally associated with gender. CONCLUSIONS: In selected patients undergoing thrombolytic therapy and cardiac catheterization for acute myocardial infarction, adjusted mortality rates and utilization of postlysis revascularization are similar in women and men. However, women may be at increased risk for reinfarction.

Age Factors↗

PubMed1993

Cerebral glucose metabolism as a predictor of recovery from aphasia in ischemic stroke.

OBJECTIVE: The recovery of language function seen in poststroke aphasia is significantly related to the severity of the initial neurologic deficit. However, a great deal of variability still remains in the improvement that is actually achieved. To detect predictors that will help in explaining this variability, positron emission tomography (PET) and fluorodeoxyglucose F 18 (18-F-fluorodeoxyglucose) were used and the results were analyzed by stepwise regression. DESIGN: Using PET imaging after injection of fluorodeoxyglucose F 18, the regional changes in glucose metabolism in 26 patients at a period of 12 to 18 days following an ischemic stroke involving the left middle cerebral artery were examined. A second PET examination was performed on 17 of our 26 patients who were able to perform speech activation exercises. All patients received an initial and a 4-month follow-up evaluation of language performance. SETTING: During the two PET studies and the first language assessment, the patients were hospitalized in a neurologic clinic. The follow-up evaluation of language performance was performed when the patients were ambulatory. PATIENTS: Twenty-six patients (10 women, 16 men; aged 38 to 77 years; mean +/- SD, 60 +/- 9.2 years) were selected in the study. Their aphasias were of various types and of varying severity ranging from mild impairment to severe global aphasia. MAIN OUTCOME MEASURES: For the stepwise regression analysis of variables, the following variables were analyzed in resting and activation PET to explain residual variance from the first to the second Token Test: regional cerebral metabolic rate for glucose of infarct and mirror region, left and right cerebral and cerebellar hemispheres, left and right Broca's area, left and right Wernicke's area, and left and right temporoparietal cortex. RESULTS: As was expected, early and late Token Tests exhibit a high correlation (.85). The stepwise regression analysis shows that only the left cerebral hemisphere glucose value of the resting PET had significant effect on the residual variance of the Token Test regression. Regional metabolic rates during speech activation had the largest contribution to a significant recovery from aphasia. The infarct area and its corresponding mirror region, the left Broca's area, and the entire left cerebral hemisphere accounted for 80% of the residual variance. CONCLUSIONS: These results emphasize not only the application of PET activation studies in the prediction of a tissue's potential reserve capacity but also the importance of left hemisphere integrity in the recovery of functional language.

Adult↗

PubMed1996

Cerebral HMPAO SPECT in patients with major depression and healthy volunteers.

1. The authors examined the regional cerebral distribution of [Tc-99m] HMPAO using single photon emission computed tomography (SPECT) in patients with major depression and in healthy controls. 2. 19 patients and 16 healthy controls had SPECT images of the brain acquired with 740 MBq (20 mCl) of [Tc-99m] HMPAO on a triple-headed camera equipped with fan beam collimators. 3. Mean counts per pixel were measured in 13 regions of each hemisphere and compared to the mean activity in the whole brain, the ipsilateral hemisphere, and cerebellum. A "laterality score" was calculated for each structure by subtracting the mean counts per pixel in a region of the right hemisphere from the mean counts in the homotopic region of the left hemisphere and normalizing the difference by the average in both regions. The degree of hemispheric asymmetry was calculated from the absolute values of the laterality scores. 4. The distribution of HMPAO was more variable in patients than in controls; while the mean activity ratios were not significantly different in any region. Asymmetries between homotopic regions of the limbic system were more pronounced in patients than in controls. However, there were no consistent left-to-right asymmetries in either group. 5. The present data indicate that regional cerebral distribution of HMPAO may not be discretely abnormal in depression, but demonstrates heightened variability in depressives (vs. control subjects).

Adult↗