chiniofon and Myocardial-Infarction

Intracardiac thrombi can be localized and quantified by Indium-111-labelling of thrombocytes with a high sensitivity and specificity. The scintigraphic procedure has a complementary evidence to echocardiography. Scintigraphy shows activity and age of thrombosis, whereas echocardiography seems to be superior in determination of mass and localization. In older thrombi scintigraphy fails because of organisation and endothelialization of the thrombus surface. For the reason of determination of the age of an intraventricular thrombus this method might have an increasing acceptance.

Topics: Aged; Blood Platelets; Coronary Disease; Coronary Thrombosis; Heart Ventricles; Humans; Hydroxyquinolines; Indium Radioisotopes; Male; Myocardial Infarction; Organometallic Compounds; Oxyquinoline; Radionuclide Imaging; Recurrence

Eighteen patients with postinfarction left ventricular aneurysms (LVAs) were examined with Indium-111-labeled autologous platelet scintigraphy to identify intracardiac thrombi and to investigate the effect of antithrombotic agents on thrombogenesity within their LVAs. Left ventriculography (LVG), and two-dimensional echocardiography were also carried out to assess the diagnostic ability of the platelet imaging. Indium-111-platelet scintigraphy for the detection of LVA mural thrombi had a sensitivity of 60% and a specificity of 100%. Four of six patients with false-negative scintigraphic studies had been under antiplatelet therapy. Eight of the nine patients who had showed active platelet deposition on initial examination had not received antiplatelet therapy. Thereafter, five of these nine were treated with tichlopidine (300 mg/day) for 29.8 +/- 5.0 days. On the second platelet study, two had resolution and the other three had interruption of intra-aneurysmal deposition, which remained positive. In only one patient of the three, the third platelet study was performed after warfarin therapy. It took two weeks after beginning the therapy to completely interrupt platelet deposition within the LVA in this patient. ECG gated radionuclide ventriculography and Thallium-201-myocardial scintigraphy were also performed to assess left ventricular wall motion of left ventricular ejection fraction (LVEF) and myocardial blood perfusion. Thallium-201-SPECT showed apical or anteroapical perfusion defects and the radionuclide ventriculography correctly identified all 18 apical and anteroseptal aneurysms which were confirmed by LVG methods. The comparison between the thrombus positive group and the thrombus negative group was carried out on both the LVEF and the period from the last myocardial infarction to the initial platelet scanning study. There were no statistical differences in the LVEF and the interval (34.5 +/- 12.5% vs 37.3 +/- 14.6%, 39.6 +/- 52.6 days vs 89.6 +/- 108.3 days) between the two groups. These results suggest that Indium-111-labeled platelet scintigraphy can be a reliable method for the identification of active left ventricular mural thrombi and a practical method of judging antiplatelet and anticoagulant therapy.

Topics: Adult; Aged; Blood Platelets; Evaluation Studies as Topic; Heart Aneurysm; Humans; Hydroxyquinolines; Indium Radioisotopes; Male; Middle Aged; Myocardial Infarction; Organometallic Compounds; Oxyquinoline; Radionuclide Imaging; Thrombosis

Lipoxygenase metabolites of arachidonic acid have been implicated in myocardial injury induced by coronary artery occlusion and reperfusion, as dual inhibitors of the lipoxygenase and cyclooxygenase enzymes, but not selective cyclooxygenase inhibitors, reduce infarct size. However, interpretation of these studies has been clouded by the lack of specificity of the drugs previously used. A specific 5-lipoxygenase inhibitor, REV-5901, has recently been developed. This drug inhibits A23187-induced immunoreactive leukotriene B4 generation by canine neutrophils (IC50 approximately 2.5 microM), and when given intravenously, attenuates the formation of a leukotriene D4-like material in blood ex vivo. The release of bioassayable leukotriene-like material from rabbit hearts infarcted in vivo and subsequently perfused in vitro is prevented by REV-5901. Moreover, the inhibitor also acts as an end-organ antagonist to prevent the spasmogenic effects of the peptide-containing leukotrienes in vitro with an IC50 approximately 0.1 microM. REV-5901 (10 + 2 mg/kg i.v.) reduces infarct size produced by coronary artery occlusion and reperfusion in the anesthetized dog from 56.6 +/- 2 to 28.6 +/- 3.7% of the hypoperfused zone. Salvage of the ischemic myocardium occurs independently of any apparent hemodynamic effect of the drug, but is accompanied by a diminution in neutrophil accumulation in the ischemic heart. It is proposed that inhibition of leukotriene B4 formation by REV-5901 suppresses the accumulation of neutrophils, thereby attenuating neutrophil-mediated cardiac damage.

Topics: Animals; Arachidonate Lipoxygenases; Dogs; Hydroxyquinolines; Leukotriene B4; Lipoxygenase Inhibitors; Male; Myocardial Infarction; Neutrophils; Quinolines; Rabbits; SRS-A

The uptake of indium-111 labelled neutrophils was examined in 30 patients with acute myocardial infarction by planar imaging and single photon emission computed tomography. The time from venepuncture to reinjection of the autologous labelled neutrophils was less than 2.5 hours and imaging was carried out 24 hours later. Twenty three patients had a positive uptake of neutrophils in the myocardium and imaging was improved by single photon emission computed tomography. There was a significant difference between the intervals from the onset of chest pain to injection of labelled neutrophils between patients with positive and negative images; early reinjection was more likely to produce a positive image. Indeed, all nine patients reinjected within 18 hours of the onset of symptoms had positive images. The results suggest that the stimulus for activation and migration of neutrophils is transient; this is an important factor if neutrophil release products play a role in cell damage after coronary occlusion.

Topics: Acute Disease; Acute-Phase Reaction; Female; Heart; Humans; Hydroxyquinolines; Indium; Inflammation; Liver; Male; Middle Aged; Myocardial Infarction; Neutrophils; Organometallic Compounds; Oxyquinoline; Radioisotopes; Spleen; Tomography, Emission-Computed

Intracardiac and arterial thrombi were examined by scintigraphy using In-111-oxine labeled autologous platelets. In 22 cases of myocardial infarction including six with ventricular aneurysms, four had positive findings of thrombi on imaging and detected also by echocardiography. All four had ventricular aneurysms. The so-called "moya-moya" echoes (fuzzy echoes) were demonstrated in two of these four cases. We encountered two cases with positive findings on imaging in 13 with mitral valve disease. These two had systemic embolic episodes after scintigraphic examination. "Moya-moya" echoes were detected in the left atrial cavity in four with negative findings on imaging. Positive images were obtained in two of three with acute arterial occlusive disease, and in both cases platelet deposition was observed in the proximal site of obstruction. Though thrombectomy was performed for one of these two cases, no thrombus was detected at the site of platelet deposition. After one month, re-examination revealed only negative findings in all sites in both these patients. In the six cases of aortic aneurysm, three had platelet deposition within their aneurysms, and surgery was performed for these positive cases, but one of them had no thrombus. Positive images were obtained in only one of seven patients with chronic arterial occlusive disease. Coagulation tests and platelet studies were investigated for patients with positive or negative platelet scans. Only the data of the thrombo-test showed a significant difference (97 +/- 9% vs 23 +/- 7%, p less than 0.001). Three cases of positive imaging became negative after anticoagulant therapy. We tried ECT for eight cases 24 hours after injection of In-111-oxine labeled platelets. Three cases showed clear images of thrombi, while the planar images could not detect them at an early stage. Therefore, we propose that ECT can be a useful technique for diagnosing intracardiac thrombi in early stage.

Topics: Aged; Arterial Occlusive Diseases; Blood Platelets; Child; Child, Preschool; Heart Diseases; Humans; Hydroxyquinolines; Indium; Infant; Infant, Newborn; Male; Myocardial Infarction; Organometallic Compounds; Oxyquinoline; Thrombosis; Tomography, Emission-Computed

Since indium-111 platelet scintigraphy for the detection of left ventricular thrombosis often shows considerable non-specific blood pool activity a subtraction method using simultaneous technetium-99m blood pool scintigraphy was undertaken in 11 subjects with well documented remote myocardial infarction, who served as positive or negative controls, and in 18 consecutive patients with acute myocardial infarction. The results were compared with those of cross sectional echocardiography. Thirteen patients had transmural myocardial infarction and the calculated count per pixel in the left ventricle of the subtracted indium-111 platelet scintigram was (mean (SD)) 0.28(0.35), but five patients with subendocardial myocardial infarction had a mean count of 0.04(0.06). In seven patients with transmural myocardial infarction (two anterior and five inferior) left ventricular thrombosis was detected by indium-111 platelet scintigraphy but in only one of these by cross sectional echocardiography. None of the patients with subendocardial myocardial infarction had left ventricular thrombosis. Subtracted left ventricular counts correlated well with the visual results. It is concluded that left ventricular platelet sequestration after acute myocardial infarction may be quantified and precisely located and that quantitative longitudinal studies of the natural history and drug intervention are now possible.

Topics: Adult; Aged; Blood Platelets; Echocardiography; Female; Heart; Heart Ventricles; Humans; Hydroxyquinolines; Indium; Male; Middle Aged; Myocardial Infarction; Organometallic Compounds; Oxyquinoline; Radionuclide Imaging; Subtraction Technique; Thrombosis