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Detection of active left ventricular thrombosis during acute myocardial infarction using indium-111 platelet
Insights
Platelet scintigraphy using indium-111 effectively identifies left ventricular thrombosis in patients with anterior myocardial infarction. This imaging technique aids in monitoring therapy for patients at risk of embolization.
Area of Science:
- Cardiology
- Nuclear Medicine
- Diagnostic Imaging
Background:
- Acute myocardial infarction (AMI) poses a risk for left ventricular thrombosis (LVT) and systemic embolization.
- Platelet scintigraphy offers a potential in vivo method to detect thrombin activity and LVT.
- Identifying LVT is crucial for guiding therapeutic interventions in AMI patients.
Purpose of the Study:
- To evaluate the utility of indium-111 platelet scintigraphy in identifying and assessing active left ventricular thrombosis in patients with acute myocardial infarction.
- To correlate scintigraphic findings with clinical outcomes, including systemic embolization and neurologic events.
- To explore the potential role of scintigraphy in monitoring antiplatelet and anticoagulant therapies.
Main Methods:
- Forty-one patients with acute myocardial infarction underwent indium-111 platelet scintigraphy.
- Platelets were labeled with indium-111 and injected intravenously.
- Patients were imaged post-injection, and followed for clinical events like death, discharge, or cardiac surgery, and evidence of systemic embolization.
Main Results:
- Left ventricular thrombosis was detected in 10 of 21 patients (48%) with anterior transmural myocardial infarctions.
- No left ventricular thrombosis or emboli were observed in patients with subendocardial or inferior transmural myocardial infarctions.
- Neurologic episodes occurred in three patients with LVT and one without, suggesting a complex relationship.
Conclusions:
- Indium-111 platelet scintigraphy is a valuable tool for identifying left ventricular thrombosis in anterior myocardial infarction.
- The technique can aid in risk stratification for systemic embolization in this patient group.
- Platelet scintigraphy may assist in monitoring the efficacy of antiplatelet and anticoagulant therapies for LVT prevention.
Abstract:
Platelet scintigraphy with radioactive indium-111 may be used both to identify and to reflect the activity of thrombin in vivo in man. Forty-one patients with acute myocardial infarction were studied for active left ventricular thrombosis by platelet scintigraphy and followed until in-hospital death, discharge, or same-admission cardiac surgery for evidence of systemic embolization. A total of 4.7 +/- 2.4 X 10(9) platelets (mean +/- 1 SD) labelled with 381 mu Ci +/- 51 mu Ci of indium-111 was injected intravenously at 91 +/- 88 hours following the onset of chest pain. Patients were imaged in multiple views on the day of and three to four days after injection of the platelet suspension. Group 1 (n = 29) had transmural myocardial infarctions, of which 21 were anterior (peak total level of creatine phosphokinase [CPK], 2,272 +/- 2,026 IU; mean +/- 1 SD) and eight were inferior (CPK level, 1,673 +/- 589 IU). Group 2 (n = 12) had subendocardial myocardial infarctions (CPK level 799 +/- 751 IU). Those with subendocardial and transmural inferior myocardial infarctions had neither left ventricular thrombosis nor emboli. Ten (48 percent) of 21 with anterior transmural myocardial infarctions had left ventricular thrombosis by platelet scintigraphy. Three with and one without such thrombosis by scintigraphy had acute neurologic episodes. In the group with anterior myocardial infarctions, seven of ten patients with and four of 11 without left ventricular thrombosis received heparin subcutaneously (chi 2 = 1.22 [Yates correction]; p greater than 0.30). We conclude that platelet scintigraphy may be used to monitor antiplatelet and anticoagulant therapy in patients with anterior transmural myocardial infarctions who are at risk for left ventricular thrombosis and systemic embolization.