technetium-tc-99m-pyrophosphate and Myocardial-Ischemia

Topics: Antibodies, Monoclonal; Coronary Circulation; Heart; Humans; Indium Radioisotopes; Myocardial Ischemia; Organometallic Compounds; Technetium; Technetium Tc 99m Pyrophosphate; Thallium; Tissue Survival; Tomography, Emission-Computed, Single-Photon

Topics: Animals; Diphosphates; Heart; Humans; Myocardial Ischemia; Myocardium; Necrosis; Radionuclide Imaging; Reperfusion Injury; Technetium Tc 99m Pyrophosphate

This report describes a 77-year-old woman with a single coronary artery who suffered an acute anterior wall myocardial infarction. The single coronary artery arose from the right coronary artery through the transverse trunk, and there were no other cardiovascular anomalies. Coronary angiography did not reveal significant coronary artery stenosis in the left anterior descending artery. The patient was treated medically in the acute phase. She developed typical angina and evidence of myocardial ischemia, and underwent successful coronary artery bypass grafting in the chronic phase with anterior chest pain.

Topics: Aged; Angina Pectoris; Coronary Angiography; Coronary Artery Bypass; Coronary Vessel Anomalies; Electrocardiography; Female; Heart; Humans; Myocardial Infarction; Myocardial Ischemia; Radiopharmaceuticals; Technetium Tc 99m Pyrophosphate; Tomography, Emission-Computed, Single-Photon

This study was undertaken to determine whether the findings of dual SPECT with Tc-99m pyrophosphate (PYP) and Tl-201 were predictive of further cardiac events after acute myocardial infarction.. The authors evaluated 88 patients with acute myocardial infarction who underwent dual SPECT for single-vessel coronary artery disease.. Twenty-nine patients showed overlapping of Tc-99m PYP and Tl-201 in the same location (overlap-positive group), and 59 patients had no overlap (overlap-negative group). In patients in the overlap-positive group, the incidence of subsequent events was significantly higher than in patients in the overlap-negative group (P < 0.001). In the overlap-positive group, the number of overlap segments in patients with further events was significantly greater than that in patients without further events (P < 0.005).. Areas with overlapping of Tc-99m PYP and Tl-201 may contain jeopardized myocardium. These results suggest that patients who have a Tc-99m PYP and Tl-201 overlap-negative scan are a low risk group, whereas patients who have more overlapping segments may require catheterization and revascularization. Thus simultaneous SPECT imaging with Tc-99m PYP and Tl-201 might be useful to identify patients with greater ischemic risk after acute myocardial infarction.

Topics: Aged; Angina Pectoris; Angioplasty, Balloon, Coronary; Cardiac Catheterization; Coronary Artery Bypass; Coronary Disease; Death, Sudden, Cardiac; Female; Follow-Up Studies; Forecasting; Heart; Humans; Image Processing, Computer-Assisted; Incidence; Male; Middle Aged; Myocardial Infarction; Myocardial Ischemia; Predictive Value of Tests; Radiopharmaceuticals; Recurrence; Risk Factors; Technetium Tc 99m Pyrophosphate; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

To evaluate whether the findings of dual single-photon emission computed tomography (SPECT) with technetium-99m pyrophosphate (Tc-99m PPi) and thallium-201 were predictive of further cardiac events in their hospital course, we studied 130 patients recovering from acute myocardial infarction (AMI). Fifty-four patients showed overlapping of Tc-99m PPi and thallium-201 in the same location (overlap positive group), and 76 patients had no overlap (overlap negative group). Of the 130 patients, 36 (28%) had a cardiac event. In patients in the overlap positive group, the incidence of subsequent events was significantly higher than in patients in the overlap negative group (44% versus 16%; p < 0.001). In the overlap positive group, the Tc-99m PPi uptake score and the number of overlap segments in patients with further events was significantly higher than those in patients without further events (10.2 +/- 5.1 versus 6.4 +/- 4.1, p < 0.005 and 5.2 +/- 2.0 versus 3.3 +/- 1.3, p < 0.001, respectively). These results suggest that patients who have a Tc-99m PPi and thallium-201 overlap negative scan can be candidates for early hospital discharge. In contrast, patients who have a greater number of overlap segments may require early catheterization and revascularization, so that simultaneous SPECT imaging Tc-99m PPi and thallium-201 might be useful for identifying patients with further ischemic risk after AMI in their hospital course.

Topics: Aged; Female; Humans; Male; Middle Aged; Myocardial Infarction; Myocardial Ischemia; Prognosis; Radiopharmaceuticals; Technetium Tc 99m Pyrophosphate; Thallium Radioisotopes; Tomography, Emission-Computed, Single-Photon

To find how some technetium-complexes to deliver the active species, TcO4(3-), to the target tissue from a dissociable polynuclear Tc5+ species in preserved states in vivo.. Effect of dissociation ability of the polynuclear Tc5+ complexes on their accumulation in ischemic myocardium was tested. Ability of dissociation as having an appropriate conformation to become biologically functional after entering the blood circulation was tested using a simple dilution method by thin layer chromatography (TLC) analysis. Various degree of ischemic myocardium slices of rat were incubated with 1/100 diluted 99mTc(5+)-succimer, 99mTc(5+)-GH and 99mTc(5+)-PPi.. The TLC patterns of 99mTc(5+)-GH and 99mTc(5+)-PPi showed the presence of a fast increasing of free Tc-species as dilution degree increased. The relative radioactivity of peak of free pertechnetate (Rf = 0.85-1.0) with 1:500 dilution was: 99mTc(5+)-succimer 0%, 99mTc(5+)-GH 28.1% +/- 1.3%, and 99mTc(5+)-PPi 46.0% +/- 2.9% respectively. The uptake of the myocardium after ischemia for 3 h was 99mTc(5+)-succimer 420% +/- 110% dose/g tissue, 99mTc(5+)-GH 710% +/- 180% dose/g tissue, and 99mTc(5+)-PPi 1295% +/- 390% dose/g tissue respectively.. The dissociation and myocardial uptake showed: 99mTc(5+)-succimer < 99mTc(5+)-GH < 99mTc(5+)-PPi, the uptake by the ischemic myocardium is positively correlated to their dissociation.

Topics: Animals; Drug Stability; In Vitro Techniques; Myocardial Ischemia; Myocardium; Organotechnetium Compounds; Radiopharmaceuticals; Rats; Sugar Acids; Technetium Tc 99m Pyrophosphate

Ischemic cell injury and the uptake mechanism of 99mTc-PYP (Pyrophosphate) were studied with preconditioning and calcium antagonist.. The coronary artery of an adult mongrel dog was clamped for 1 hour, followed by reperfusion and 99mTc-PYP injection. A control group (group C, n = 8), a group in which continuous drip infusion of diltiazem (10 mg/kg) (group D, n = 7), and a group preconditioned by six 5-minute clampings and perfusions before occlusion (group P, n = 6) were compared.. Wall motion was fully recovered in group D but not in group P after 2 hours of reperfusion. The 99mTc-PYP uptake ratio showed a significant (p < 0.05) reduction in group D (11.5 : 3.6 compared with group C), but not in group P (11.5 : 9.1, p = 0.25). The infarct area was 1.2 +/- 0.6% of the left ventricle in group D, 1.3 +/- 0.4 in group P, and 6.4 +/- 1.0 in group C (p < 0.01 in groups D and P vs. group C).. These findings suggest that preconditioning does not alleviate stunning, but it improves cell injury in spite of high uptake of 99mTc-PYP. Diltiazem protects from both stunning and cell injury, suggesting a different mechanism of myocardial protection from that of preconditioning.

Topics: Animals; Calcium Channel Blockers; Coronary Circulation; Diltiazem; Dogs; Myocardial Infarction; Myocardial Ischemia; Radionuclide Imaging; Technetium Tc 99m Pyrophosphate

We investigated metabolic factors related to the recovery of myocardial function during ischemia and after reperfusion using dichloroacetic acid (DCA) in canine models with repeated 10-min regional ischemia and reperfusion. Administration of 100 mg/kg DCA, which activates pyruvate dehydrogenase, improved regional wall motion significantly as compared with the nontreated controls (p < 0.05). The mechanism was studied by determining changes in myocardial levels of pH, glucose, lactate, and nonesterified fatty acids (NEFA). Glucose extraction was increased significantly during ischemia and reperfusion by the pretreatment of DCA (p < 0.01). the calculated contribution of glucose to myocardial oxidative metabolism during ischemia and reperfusion was greater than that of NEFA and lactate in case of DCA treatment. The uptake of [99mTc]pyrophosphate (PYP), which reflects myocardial injury, was also significantly suppressed by DCA (p < 0.01). pH was not affected by an infusion of DCA. These findings suggest that the activation of glucose metabolism by DCA, which is impaired and reduced during ischemia and reperfusion, may be responsible for the improved myocardial function after reperfusion.

Topics: Animals; Blood Glucose; Calcium; Coronary Circulation; Dichloroacetic Acid; Dogs; Fatty Acids, Nonesterified; Glucose; Hydrogen-Ion Concentration; Lactates; Lactic Acid; Myocardial Ischemia; Myocardial Stunning; Technetium Tc 99m Pyrophosphate

Technetium-99m-pyrophosphate (PYP) is bound to calcium in necrotic myocardium and has been used clinically to evaluate myocardial infarction. Technetium-99m-PYP is also reported to accumulate in myocardium with unstable angina pectoris and it is speculated that severe ischemia with noninfarcted tissue may also increase uptake of 99mTc-PYP. In this paper, 99mTc-PYP uptake was determined in various models of myocardial ischemia of short duration to examine its applicability to the assessment of myocardial viability.. In 23 open-chest dogs under anesthesia, models of ischemia-reperfusion of the left anterior descending artery (LAD) subjected to ischemia for 10, 30 or 60 min were produced. Wall motion was examined by echocardiography and myocardial blood flow was calculated using colored microspheres. Technetium-99m-PYP was injected after each ischemic intervention and reperfusion.. Technetium-99m-PYP showed 1.18 +/- 0.009 in the uptake ratio (ischemic area/normal area) following 10-min ischemia (11 dogs). The uptake ratio following 30-min ischemia (8 dogs) showed a significantly higher increase than that following 10-min ischemia (4.09 +/- 1.75; p < 0.05), permitting in vivo and ex vivo imaging. After 60-min ischemia resulting in infarction (4 dogs), 99mTc-PYP uptake of the ischemic area showed an uptake ten times that of the normal area (transmural: 12.2 +/- 2.9, epicardium: 7.5 +/- 1.9, endocardium: 16.8 +/- 4.1).. These findings indicate that since 99mTc-PYP accumulates in injured myocardium, its concurrent use with blood flow imaging is useful for the assessment of severity of ischemia, injured area and myocardial viability.

Topics: Animals; Coronary Circulation; Dogs; Heart; Myocardial Contraction; Myocardial Infarction; Myocardial Ischemia; Myocardial Reperfusion Injury; Radionuclide Imaging; Technetium Tc 99m Pyrophosphate; Time Factors; Tissue Survival

A 71-year-old woman with unstable angina was admitted to our department. Upon admission, electrocardiography revealed a QS pattern in Leads V1-V3. Left ventriculography disclosed akinesis of the anterior wall and the septum. Myocardial scintigraphy with 99mTc-pyrophosphate (PYP) revealed marked accumulation (Parkey's grade III) in the anterior wall, septum and apical region. Coronary arteriography revealed stenosis (99% with delay) in the LAD #6. Based on these findings, we performed percutaneous transluminal coronary angioplasty (PTCA) on this patient. About 3 months later, the patient underwent PTCA again because stenosis had recurred. The resting 201Tl myocardial scintigram, taken immediately after the first PTCA, demonstrated complete defects in the anterior wall, septum and apical region. After the second PTCA, no stenosis was observed. About 1 year later, the wall motion returned to normal (except in part of the apical region), suggesting that this was a case of stunned myocardium. On the same occasion, the 201Tl uptake was normal except in the apical region. The present case was regarded as stunned myocardium which demonstrated marked radioactivity accumulation when examined by 99mTc-PYP myocardial scintigraphy. In the past, 99mTc-PYP has been thought to be incorporated into irreversibly impaired myocardium (e.g., in cases of acute myocardial infarction). The uptake of 99mTc-PYP into stunned myocardium has not been reported before. Thus, this case is rare and noteworthy.

Topics: Aged; Angina, Unstable; Angioplasty, Balloon, Coronary; Female; Heart; Humans; Myocardial Ischemia; Myocardium; Radionuclide Imaging; Technetium Tc 99m Pyrophosphate