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Biomedical subjects

D G Mathey

Publications and source records attributed to D G Mathey.

At least 55 records · Page 3Linked to original sources

Thallium-201/technetium-99m pyrophosphate overlap in patients with acute myocardial infarction after thrombolysis: prediction of depressed wall motion despite thallium uptake.

Intracoronary thallium-201/technetium-99m pyrophosphate planar scintigraphy was performed in 60 patients with acute myocardial infarction undergoing intracoronary thrombolysis to predict salvage of myocardium immediately after thrombolysis. In eight patients a significant overlap of new thallium uptake and technetium pyrophosphate accumulation was found after thrombolysis. Intravenous planar thallium scintigraphy revealed thallium uptake in the region of overlap in all patients; circumferential profile analysis showed no difference in the thallium scintigrams before and after technetium injections. Both findings indicate that overlap is not the result of scattering of technetium into the thallium window. Emission computed tomography revealed thallium/technetium pyrophosphate uptake in identical slices and regions. Regional wall motion in the area of overlap remained depressed in all patients, in contrast to patients with similar thallium uptake without overlap. These data suggest that thallium/technetium pyrophosphate overlap reflects the close proximity of viable and necrotic myocardial cells and predicts depressed wall motion after thrombolysis.

Adult↗

Advantages and applications of the centerline method for characterizing regional ventricular function.

We sought to identify theoretical advantages and applications of the centerline method for quantitative assessment of regional ventricular function. Motion was measured along 100 chords constructed perpendicular to a centerline drawn midway between the end-diastolic and end-systolic contours, and normalized for heart size. Abnormality was expressed in units of standard deviations from the mean motion in a normal reference population to indicate both the severity and significance of the wall motion abnormality. The mean abnormality averaged over 100 chords correlated highly with the area ejection fraction (r = .97). The centerline method uses a "sliding window" to measure motion where it is abnormal, because assessment of wall motion in predefined regions of the ventricular contour underestimates abnormality. From the 100 data points, the extent (% of contour) of regional abnormalities can also be determined. The severity of hypokinesis at the site of acute myocardial infarction correlated better with infarct size estimated from creatine kinase release (r = -.78) than did the ejection fraction or the circumferential extent of hypokinesis. Because the centerline method measures motion along locally determined vectors, and requires no apex, origin, coordinate system, or geometric reference figure, it can be applied to contours as dissimilar as the 60 degree left anterior oblique projection of the left ventricle and the 75 degree left anterior oblique projection of the right ventricle.

Computers↗

Measurement of regional wall motion from biplane contrast ventriculograms: a comparison of the 30 degree right anterior oblique and 60 degree left anterior oblique projections in patients with acute myocardial infarction.

The value of performing biplane vs single plane analysis of regional wall motion from contrast ventriculograms was determined in 102 patients who received thrombolytic therapy and who underwent biplane ventriculography during acute myocardial infarction (n = 67), at follow-up more than 2 weeks later (n = 80), or both (n = 45). Hypokinesis in the infarct region and hyperkinesis in the noninfarct region were measured by the centerline method in the respective artery territories, which were defined from the data of 62 patients with single-vessel disease and were expressed in units of standard deviations from the mean of 32 normal subjects. Hypokinesis was more severe and extended over a longer segment of the left ventricular contour when measured in the right anterior oblique (RAO) projection in thrombosis of the left anterior descending coronary artery (LAD) but more severe and extensive in the left anterior oblique (LAO) projection in circumflex stenosis. Hyperkinesis opposite the LAD or the circumflex was greater in the LAO projection. In patients with thrombosis of the right coronary artery, wall motion abnormalities were similar in the two projections. Thus the evaluation of hypokinesis caused by acute coronary thrombosis and of the effect of therapeutic interventions in salvaging function can be adequately evaluated from single-plane 30 degree RAO ventriculograms, except in the small minority of patients with circumflex thrombosis.

Cineradiography↗

Development of pulmonary aneurysm in primary pulmonary hypertension: a case report.

Selected cases of severe primary pulmonary arterial hypertension and associated pulmonary vascular disease have been related to the oral ingestion of aminorex fumarate, an anorexigen obviously responsible for an epidemic of primary pulmonary hypertension in Western Europe between 1967 and 1970. This report describes a fifteen year follow-up of a female patient with aminorex fumarate related pulmonary hypertension and the uncommon finding of the formation of an excessive fusiform pulmonary trunk aneurysm in the late stage of the disease process. The progressive clinical course was followed by serial chest x-ray films and repeat right heart catheterization. The diagnosis of a main stem pulmonary artery aneurysm was noninvasively established by two-dimensional echocardiography and confirmed by contrast-enhanced computed tomography and radionuclide blood pool imaging. The patient is alive, thus no histologic correlate of this entity is available at present.

Aminorex↗

Treatment of pulmonary hypertension.

Reversible causes of pulmonary hypertension, such as mitral stenosis or pulmonary embolism, should be corrected causally. The therapy of pulmonary hypertension is difficult in those diseases where the causes or mechanisms are not understood or are unknown. In chronic obstructive lung disease, the primary objective is to improve airflow and alveolar ventilation (theophylline, beta-sympathicomimetics). Long-term oxygen (more than 18 hours a day) should be used in patients with paO2 below 55 mm Hg, since a reduction in pulmonary vascular resistance and a prolonged survival has been demonstrated. The role of vasodilator therapy (hydralazine, nitrates, diazoxide, captopril, calcium-blockers and others) in chronic obstructive lung disease remains uncertain. In primary pulmonary hypertension, a pulmonary vasodilator is recommended after demonstrating (for example with an infusion of prostaglandin I2), that the increased pulmonary vascular resistance is still reversible. The initiation of therapy should be performed cautiously under hemodynamic monitoring.

Adrenergic beta-Agonists↗

[Early noninvasive detection of reperfusion and infarct by intravenous technetium 99m pyrophosphate scintigraphy following thrombolysis].

To determine whether technetium-99-pyrophosphate accumulation immediately after intravenous thrombolysis can serve as a marker of reperfusion and infarct size, 17 patients with acute myocardial infarction were studied. Immediately after thrombolysis 10 mCi of technetium-99m pyrophosphate were injected intravenously. Coronary and left ventricular angiography were then performed in all patients, revealing patent coronary arteries in 13 patients. In all patients, 0.3 and 0.5 mCi of thallium-201 were injected into the right and left coronary artery, respectively, followed by planar scintigraphy. 6 patients with patent coronary arteries and a large thallium-201 defect had massive (more than one third of the cardiac silhouette) pyrophosphate accumulation (group A), whereas 7 patients with a small or no thallium-201 defect in the presence of a patent infarct artery had either focal or no pyrophosphate accumulation (group B). In contrast, 4 patients with an occluded infarct artery showed no acute pyrophosphate uptake despite a large thallium-201 defect (group C). Emission computed tomography confirmed the planar scintigraphic data in group A patients and revealed small thallium-201 defects and focal pyrophosphate accumulation in group B patients with negative planar scintigrams. Global and regional ejection fractions in the infarct area, measured from the acute and follow-up left ventricular angiograms, were higher in group A than in group B and C patients. It is concluded that early intravenous technetium-99m pyrophosphate scintigraphy in patients with acute myocardial infarction undergoing intravenous thrombolysis may serve as an indicator of reperfusion and infarct size.

Adult↗

Double-blind randomised trial of intravenous tissue-type plasminogen activator versus placebo in acute myocardial infarction.

In a double-blind randomised trial 129 patients with first myocardial infarction of less than 6 h duration were allocated to treatment with human recombinant tissue-type plasminogen activator (rt-PA) given intravenously over 90 min, or to placebo infusion. Coronary angiography at the end of this infusion showed that the infarct-related vessel was patent in 61% of 62 assessable coronary angiograms in the rt-PA-treated group compared with 21% in the control group. Treatment with rt-PA was not accompanied by any major complications. In the rt-PA group the circulating fibrinogen level at the end of the catheterisation was 52 +/- 29% (mean +/- SD) of the starting value.

Adult↗

[Time dependence of myocardial preservation after thrombolysis. Consequences for indication and procedure].

To examine whether the limitation in infarct size after effective thrombolytic therapy is time-dependent the relationship between left ventricular wall motion in the infarct region and the time interval between onset of symptoms and intracoronary streptokinase infusion was investigated. The relationship was significant: When intracoronary thrombolytic therapy was begun within 2 hours, wall motion was almost always within normal limits, whereas the probability of wall motion improvement fell to less than 50%, when treatment was begun later. As a further step a lysis procedure was examined which took account of these findings: the intravenous bolus injection of urokinase. Approximately one hour after bolus injection coronary patency could be demonstrated angiographically in 60% of the infarct patients. A clinically relevant limitation of the infarct size was found in those patients in whom lysis therapy could be begun within 2 hours. On the basis of these findings, a thrombolytic therapy seems to be indicated in all patients with acute myocardial infarction when lysis treatment can be begun within 2 hours. The intravenous urokinase therapy, by virtue of its simplicity, is an alternative to intravenous streptokinase therapy.

Angiography↗

Kinetics of serum creatine kinase and creatine kinase-MB after intracoronary thrombolysis.

The kinetics of the activity of total creatine kinase (CK) and creatine phosphokinase isoenzyme muscle-brain were investigated in 48 patients with acute myocardial infarction after successful intracoronary thrombolysis, and compared to the enzyme activities in 17 patients in whom thrombolysis failed. CK activity peaked significantly earlier after a successful thrombolysis than after an unsuccessful attempt: in patients with successful thrombolysis, CKmax = 10.5 +/- 3.7 h and in patients with an unsuccessful attempt, CKmax = 19.3 +/- 5.9 h; p less than or equal to 0.05. The area under the activity time curve after successful thrombolysis was significantly smaller than after unsuccessful thrombolysis: in patients with successful thrombolysis, CK area = 25,255 U/l per day and in patients with an unsuccessful attempt, CK area = 32,602 U/l per day; p = 0.015. There was a negative correlation between the area under the CK serum curve after successful thrombolysis, and the change of regional wall motion at the site of the acute infarct (p less than or equal to 0.05). From the smaller area under the CK curve in patients after successful thrombolysis, and the significant negative correlation of this measurement with regional left ventricular wall motion, we conclude that myocardial salvage after intracoronary thrombolysis can be assessed by serial CK measurements.

Coronary Circulation↗

Intravenous urokinase in acute myocardial infarction.

To achieve reperfusion early, an intravenous bolus of 2 million units of urokinase was administered in 50 patients with transmural acute myocardial infarction (AMI) 1.8 +/- 2.5 hours after the onset of symptoms. Coronary angiography performed 1.1 +/- 0.6 hours after urokinase therapy revealed patent coronary arteries in 30 patients (60%), with no significant difference between those with anterior and those with inferior AMI. Reocclusion occurred in only 1 of 24 patients restudied. Failure to achieve reperfusion was not related to the degree of systemic fibrinolytic activity, which was equally high in patients who did and those who did not achieve reperfusion, as evident from serially obtained fibrinogen measurements (77 +/- 52 vs 84 +/- 24 mg/dl, difference not significant). Plasmin activity, measured serially from 15 minutes to 24 hours after urokinase in 7 patients, was maximal at 15 minutes and undetectable after 3 hours. Wall motion at the infarct site measured from contrast ventriculograms was significantly better at follow-up only in patients in whom reperfusion was achieved and who received urokinase within 2 hours after the onset of symptoms as compared with patients in whom reperfusion was not achieved (-1.2 +/- 1.4 vs -2.4 +/- 0.9 standard deviations from normal, p less than 0.05). Peak serum creatine kinase level was significantly lower in patients in whom reperfusion was achieved than in those in whom it was not or those who had rethrombosis (802 +/- 763 vs 1,973 +/- 1,071 U/liter, p less than 0.005).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

Time from onset of symptoms to thrombolytic therapy: a major determinant of myocardial salvage in patients with acute transmural infarction.

To determine whether myocardial salvage after successful intracoronary or intravenous thrombolysis is time dependent, the relation between left ventricular wall motion and the time to treatment was studied in 69 patients admitted less than 3 hours after onset of acute transmural myocardial infarction (42 patients with reperfusion by intracoronary streptokinase, 27 by intravenous urokinase). A similar significant relation between the time to treatment and the severity of regional hypokinesia at follow-up was found in the intracoronary and intravenous groups. To better define this relation, particularly during the early phase of infarction, the groups were combined. In patients in whom thrombolytic treatment was initiated within 2 hours after symptom onset, wall motion at follow-up was within 2 standard deviations of the normal mean in 82% (14 of 17 patients). If treatment was started 2 to 5 hours after symptom onset, the probability of improved wall motion decreased to 46% (24 of 52 patients, p less than 0.025). The time/wall motion relation appeared to be independent of infarct location, angiographically visible collateral vessels and the presence of subtotal coronary artery occlusion. The severity of hypokinesia at follow-up study correlated with the magnitude of peak serum creatine kinase (r = -0.71), indicating that thrombolytic therapy initiated within 2 hours after the onset of symptoms improves regional left ventricular function and reduces infarct size more than later therapy does.

Adolescent↗

Scintigraphic evidence of the "no reflow" phenomenon in human beings after coronary thrombolysis.

To assess whether the absence of new thallium-201 uptake after successful intracoronary thrombolysis reflects a disturbance of myocardial cell function or lack of capillary reperfusion, dual isotope scintigraphic studies with thallium-201 and technetium-99m micro-albumin aggregates were performed in 16 patients with acute anterior myocardial infarction. Intracoronary thallium-201 and technetium-99m scintigraphy performed before intracoronary thrombolysis in 12 of the 16 patients resulted in identical thallium-201 and technetium-99m defect sizes. Immediately after intracoronary thrombolysis, thallium-201 and technetium-99m scintigraphy was repeated in 11 of the 12 patients. In 4 of the 11, the initial thallium and technetium scintigraphic defects were significantly reduced, and in 6 of the 11, they were only slightly reduced; there was no difference in the size of the residual defect as assessed with both radionuclides in all 10 of the 11 patients. In the eleventh patient, there was a significant reduction of the initial technetium-99m scintigraphic defect but no change in the size of the thallium-201 defect. In four other patients, scintigrams were obtained only after intracoronary thrombolysis; these revealed no difference in thallium-201 and technetium-99m defect size. In seven of eight patients restudied 2 to 4 weeks after intracoronary thrombolysis, thallium-201 and technetium-99m defect sizes were identical with those immediately after intracoronary thrombolysis; in the eighth patient there was no difference in thallium-201 and technetium-99m defect size, although such a difference had been present immediately after intracoronary thrombolysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

Clinical use of ultrashort-lived radionuclide krypton-81m for noninvasive analysis of right ventricular performance in normal subjects and patients with right ventricular dysfunction.

The ultrashort-lived radionuclide krypton-81m, eluted in 5% dextrose from a bedside rubidium-81m generator, was intravenously infused for rapid imaging of the right-sided heart chambers in the right anterior oblique projection adjusted for optimal right atrioventricular separation. Left-sided heart and lung background was minimized by rapid decay and efficient exhalation of krypton-81m, requiring no algorithm for background correction. A double region of interest method decreased the variability in the assessment of ejection fraction to 5%. In 10 normal subjects, 11 patients with pulmonary hypertension, 4 patients with right ventricular outflow tract obstruction and 4 patients with right ventricular infarction, right ventricular ejection fraction determined by krypton-81m equilibrium blood pool imaging ranged from 14 to 76%. The correlation between these values and those determined by cineangiography according to Simpson's rule was close: r = 0.93 for all data points (p less than 0.001), r = 0.92 for studies at rest (p less than 0.001) and r = 0.93 for exercise studies (p less than 0.001). Exercise-related changes in right ventricular function revealed a disturbed functional reserve with pulmonary hypertension and right ventricular infarction, whereas in compensated right ventricular outflow tract obstruction there was a physiologic increase in ejection fraction with exercise (p less than 0.001). Thus, equilibrium-gated right ventricular imaging using ultrashort-lived krypton-81m is a simple, accurate and reproducible method with potential for serial assessment of right ventricular ejection fraction in a variety of right ventricular anatomic and functional abnormalities, both at rest and during exercise. Advantages of this method include an extremely low radiation dose to patients and clear right atrioventricular separation without the need to correct for background activity.

Adult↗

First clinical results with digital flashing tomosynthesis in coronary angiography.

Digital flashing tomosynthesis (D-FTS) investigations have been performed using a new nonlinear reconstruction algorithm. It is called extreme-value decoding and produces significantly less artefact than back projection used commonly in tomosynthesis. The reduction of artefact allows the use of tomosynthesis based on only four projections in the case of dilute objects, i.e. objects with only a small number of high absorbing voxels. This condition can be realized in angiography by cancelling soft-tissue and bones by subtraction (e.g. DSA technique). The new technique has been carried out in 10 patients with coronary artery disease after investigation with standard 35 mm cineangiography. For the recording step of the D-FTS images we have used a multiple X-ray source. For the digital nonlinear reconstruction step we have used a VAX 11/780 computer. The estimated degree of stenosis found by D-FTS tomograms shows good accordance with the cineangiographic studies. The amount of contrast medium, the X-ray dose, and the investigation time are significantly reduced, because D-FTS requires only a single pre- and post-injection multiple perspective-image for each coronary artery.

Cineangiography↗

Coronary angiography with flashing tomosynthesis.

Thirty-four patients with coronary artery disease were studied with standard 35 mm coronary cineangiography and flashing tomosynthesis, to assess the value of the latter technique to detect stenotic coronary arteries. All occluded vessels and all coronary stenoses seen by cineangiography were also found by flashing tomosynthesis. A correlation coefficient of r = 0.85 (P less than 0.001) was determined between the degrees of stenosis obtained by the two techniques. With flashing tomosynthesis, less contrast medium was needed, the investigation time was shorter, and the radiation exposure markedly reduced. At present, dynamic events, such as collateral blood flow, cannot be evaluated. We conclude that coronary arterial stenoses and occlusions can be reliably evaluated by flashing tomosynthesis. Further technological developments are necessary for the technique to gain clinical acceptance.

Adult↗

Factors that determine recovery of left ventricular function after thrombolysis in patients with acute myocardial infarction.

The coronary and ventricular angiograms of 47 patients with acute myocardial infarction in whom reperfusion was achieved by intracoronary streptokinase were quantitatively analyzed to determine the factors that affect recovery of regional left ventricular function after reperfusion. Hypokinesis in the infarct region was measured by the centerline method and expressed in terms of standard deviations (SDs) from normal. Severity of coronary artery stenosis was measured quantitatively. Hypokinesis showed more significant improvement after thrombolysis in patients with minimum stenosis diameter of greater than 0.4 mm than in those with severe residual stenosis, i.e., stenosis producing a minimum diameter of 0.4 mm or less (1.0 +/- 1.3 SD/chord, n = 31, vs 0.0 +/- 0.9 SD/chord, n = 7; p less than .05). Improvement in hypokinesis was greater in patients who received thrombolytic therapy within 2 hr than in those treated later (2.1 +/- 1.1, n = 8, vs 0.7 +/- 1.0 SD/chord, n = 28; p less than .001). These results indicate that angiographic reperfusion alone may not be sufficient: reperfusion must provide adequate flow and be achieved early to salvage myocardial function.

Adult↗

Lysis of left ventricular thrombi with urokinase.

In 16 patients with recent myocardial infarction (3 to 12 week old) and with large left ventricular thrombi systemic thrombolysis with urokinase was performed. Left ventricular thrombi were diagnosed by two-dimensional echocardiography; in all patients the mural thrombus was located in the area of recent myocardial infarction. Each of three patients suffered an embolic episode before the initiation of thrombolytic therapy and the episode caused a stroke in one. Urokinase was infused intravenously at a rate of 60,000 U/hr for 2 to 8 days in combination with intravenous heparin (200 units/kg X 12 hr). Left ventricular thrombi were successfully lysed in 10 of 16 patients, as determined by two-dimensional echocardiography. In four of the six remaining patients only partial thrombolysis was achieved and in two thrombolytic treatment failed. There was no evidence of embolic events during thrombolysis in any of the 16 patients. The success of thrombolysis seemed to depend on the age of the thrombus: the thrombus was dissolved in eight of nine patients undergoing thrombolysis within 4 weeks of the acute myocardial infarction vs in two of seven patients receiving treatment later (p = .057). The presence of a left ventricular aneurysm or depressed left ventricular function also appeared to reduce the likelihood of successful thrombolysis. All patients were discharged on oral anticoagulants. At 6 months follow-up (n = 9) no recurrence of left ventricular thrombus was found. These results show that left ventricular thrombi can be safely lysed by intravenous urokinase. However, for better definition of the risk and benefit of this new therapy further investigation is necessary.

Adult↗