Purpose: Regadenoson (REG) is currently becoming the stress agent of choice in patients undergoing pharmacologic single photon emission computed tomography (SPECT). However, in patients with left bundle branch block (...Purpose: Regadenoson (REG) is currently becoming the stress agent of choice in patients undergoing pharmacologic single photon emission computed tomography (SPECT). However, in patients with left bundle branch block (LBBB) and ventricular paced rhythm (VPR), hesitation exists amongst clinicians to use REG-SPECT due to the concern that the increased heart rate could cause false positive SPECT results. We sought to evaluate the comparability of A-SPECT and REG-SPECT in patients with LBBB and VPR. Methods: Retrospective study of 30 patients who served as their own controls. All 30 patients who underwent REG-SPECT (Grp 1) were compared to their prior A-SPECT (Grp 2) done within two years prior to REG-SPECT. Heart rate (HR) and blood pressure (BP) parameters, ECG, stress perfusion and gated variables, SPECT ischemia, and side-effects were evaluated. Statistical significance was set at P < 0.05. Results: Grp 1 and Grp 2 were comparable in hemodynamic parameters with increase in HR and decrease in systolic and diastolic BP with administration of adenosine and REG stress agents. However, there were no significant differences found in hemodynamic parameters and II degree AV block between the groups. All normal A-SPECT were found to be normal with REG-SPECT. No differences could be found between the two groups among SPECT parameters. Muscle pain was significantly higher in REG (10.0% vs. 0.0%, P = 0.083) and so was the use of aminophylline (16.7% vs. 0.0%, P = 0.025) to relieve the side-effect. Conclusion: REG-SPECT can be administered in patients with LBBB and VPR patients based on favorable and comparable hemodynamic responses and arrhythmia occurrences to A-SPECT. REG-SPECT can also be used for adequate interpretation of presence or absence of SPECT ischemia particularly in the LAD territory without any concern for false positive perfusion defects.展开更多
The previous pharmacokinetic methods can be only limited to drug analysis in vitro, which provide less information on the distribution and metabolismof drugs, and limit the interpretation and assessment of pharmacokin...The previous pharmacokinetic methods can be only limited to drug analysis in vitro, which provide less information on the distribution and metabolismof drugs, and limit the interpretation and assessment of pharmacokinetics, the determination of metabolic principles, and evaluation of treatment effect. The objective of the study was to investigate the pharmacokinetic characteristics of gene recombination angiogenesis inhibitor Kringle 5 in vivo. The SPECT/CT and specific^(131)I-Kringle 5 marked by Iodogen method were both applied to explore the pharmacokinetic characteristics of^(131)I-Kringle 5 in vivo, and to investigate the dynamic distributions of^(131)I-Kringle 5 in target organs. Labeling recombinant angiogenesis inhibitor Kringle 5 using131 I with longer half-life and imaging in vivo using SPECT instead of PET,could overcome the limitations of previous methods. When the doses of^(131)I-Kringle 5 were 10.0, 7.5 and5.0 g/kg, respectively, the two-compartment open models can be determined within all the metabolic process in vivo. There were no significant differences in t1/2α, t1/2β, apparent volume of distribution and CL between those three levels. The ratio of AUC(0 1)among three different groups of 10.0, 7.5 and 5.0 g/kg was 2.56:1.44:1.0, which was close to the ratio(2:1.5:1.0). It could be clear that in the range of 5.0–10.0 g/kg, Kringle 5 was characterized by the first-order pharmacokinetics. Approximately 30 min after^(131)I-Kringle 5 was injected,^(131)I-Kringle 5 could be observed to concentrate in the heart, kidneys, liver and other organs by means of planar imaging and tomography. After 1 h of being injected, more radionuclide retained in the bladder, but not in intestinal. It could be concluded that^(131)I-Kringle 5 is mainly excreted through the kidneys. About 2 h after the injection of^(131)I-Kringle 5, the radionuclide in the heart, kidneys,liver and other organs was gradually reduced, while more radionuclide was concentrated in the bladder.The radionuclide was completely metabolized within 24 h, and the distribution of radioactivity in rats was similar to normal levels. In our study, the specific marker^(131)I-Kringle 5 and SPECT/CT were successfully used to explore pharmacokinetic characteristics of Kringle 5 in rats. The study could provide a new evaluation platform of the specific, in vivo and real-time functional imaging and pharmacokinetics for the clinical application of^(131)I-Kringle 5.展开更多
文摘Purpose: Regadenoson (REG) is currently becoming the stress agent of choice in patients undergoing pharmacologic single photon emission computed tomography (SPECT). However, in patients with left bundle branch block (LBBB) and ventricular paced rhythm (VPR), hesitation exists amongst clinicians to use REG-SPECT due to the concern that the increased heart rate could cause false positive SPECT results. We sought to evaluate the comparability of A-SPECT and REG-SPECT in patients with LBBB and VPR. Methods: Retrospective study of 30 patients who served as their own controls. All 30 patients who underwent REG-SPECT (Grp 1) were compared to their prior A-SPECT (Grp 2) done within two years prior to REG-SPECT. Heart rate (HR) and blood pressure (BP) parameters, ECG, stress perfusion and gated variables, SPECT ischemia, and side-effects were evaluated. Statistical significance was set at P < 0.05. Results: Grp 1 and Grp 2 were comparable in hemodynamic parameters with increase in HR and decrease in systolic and diastolic BP with administration of adenosine and REG stress agents. However, there were no significant differences found in hemodynamic parameters and II degree AV block between the groups. All normal A-SPECT were found to be normal with REG-SPECT. No differences could be found between the two groups among SPECT parameters. Muscle pain was significantly higher in REG (10.0% vs. 0.0%, P = 0.083) and so was the use of aminophylline (16.7% vs. 0.0%, P = 0.025) to relieve the side-effect. Conclusion: REG-SPECT can be administered in patients with LBBB and VPR patients based on favorable and comparable hemodynamic responses and arrhythmia occurrences to A-SPECT. REG-SPECT can also be used for adequate interpretation of presence or absence of SPECT ischemia particularly in the LAD territory without any concern for false positive perfusion defects.
文摘The previous pharmacokinetic methods can be only limited to drug analysis in vitro, which provide less information on the distribution and metabolismof drugs, and limit the interpretation and assessment of pharmacokinetics, the determination of metabolic principles, and evaluation of treatment effect. The objective of the study was to investigate the pharmacokinetic characteristics of gene recombination angiogenesis inhibitor Kringle 5 in vivo. The SPECT/CT and specific^(131)I-Kringle 5 marked by Iodogen method were both applied to explore the pharmacokinetic characteristics of^(131)I-Kringle 5 in vivo, and to investigate the dynamic distributions of^(131)I-Kringle 5 in target organs. Labeling recombinant angiogenesis inhibitor Kringle 5 using131 I with longer half-life and imaging in vivo using SPECT instead of PET,could overcome the limitations of previous methods. When the doses of^(131)I-Kringle 5 were 10.0, 7.5 and5.0 g/kg, respectively, the two-compartment open models can be determined within all the metabolic process in vivo. There were no significant differences in t1/2α, t1/2β, apparent volume of distribution and CL between those three levels. The ratio of AUC(0 1)among three different groups of 10.0, 7.5 and 5.0 g/kg was 2.56:1.44:1.0, which was close to the ratio(2:1.5:1.0). It could be clear that in the range of 5.0–10.0 g/kg, Kringle 5 was characterized by the first-order pharmacokinetics. Approximately 30 min after^(131)I-Kringle 5 was injected,^(131)I-Kringle 5 could be observed to concentrate in the heart, kidneys, liver and other organs by means of planar imaging and tomography. After 1 h of being injected, more radionuclide retained in the bladder, but not in intestinal. It could be concluded that^(131)I-Kringle 5 is mainly excreted through the kidneys. About 2 h after the injection of^(131)I-Kringle 5, the radionuclide in the heart, kidneys,liver and other organs was gradually reduced, while more radionuclide was concentrated in the bladder.The radionuclide was completely metabolized within 24 h, and the distribution of radioactivity in rats was similar to normal levels. In our study, the specific marker^(131)I-Kringle 5 and SPECT/CT were successfully used to explore pharmacokinetic characteristics of Kringle 5 in rats. The study could provide a new evaluation platform of the specific, in vivo and real-time functional imaging and pharmacokinetics for the clinical application of^(131)I-Kringle 5.
