Symptomatic relief precedes improvement of myocardial blood flow in patients under spinal cord stimulation

BACKGROUND: Spinal cord electrical stimulation (SCS) has shown to be a treatment option for patients suffering from angina pectoris CCS III-IV although being on optimal medication and not suitable for conventional treatment strategies, e.g. CABG or PTCA. Although many studies demonstrated a clear symptomatic relief under SCS therapy, there are only a few short-term studies that investigated alterations in cardiac ischemia. Therefore doubts remain whether SCS has a direct effect on myocardial perfusion. METHODS: A prospective study to investigate the short- and long-term effect of spinal cord stimulation (SCS) on myocardial ischemia in patients with refractory angina pectoris and coronary multivessel disease was designed. Myocardial ischemia was measured by MIBI-SPECT scintigraphy 3 months and 12 months after the beginning of neurostimulation. To further examine the relation between cardiac perfusion and functional status of the patients we measured exercise capacity (bicycle ergometry and 6-minute walk test), symptoms and quality of life (Seattle Angina Questionnaire [SAQ]), as well. RESULTS: 31 patients (65 ± 11 SEM years; 25 male, 6 female) were included into the study. The average consumption of short acting nitrates (SAN) decreased rapidly from 12 ± 1.6 times to 3 ± 1 times per week. The walking distance and the maximum workload increased from 143 ± 22 to 225 ± 24 meters and 68 ± 7 to 96 ± 12 watt after 3 months. Quality of life increased (SAQ) significantly after 3 month compared to baseline, as well. No further improvement was observed after one year of treament. Despite the symptomatic relief and the improvement in maximal workload computer based analysis (Emory Cardiac Toolbox) of the MIBI-SPECT studies after 3 months of treatment did not show significant alterations of myocardial ischemia compared to baseline (16 patients idem, 7 with increase and 6 with decrease of ischemia, 2 patients dropped out during initial test phase). Interestingly, in the long-term follow up after one year 16 patients (of 27 who completed the one year follow up) showed a clear decrease of myocardial ischemia and only one patient still had an increase of ischemia compared to baseline. CONCLUSION: Thus, spinal cord stimulation not only relieves symptoms, but reduces myocardial ischemia as well. However, since improvement in symptoms and exercise capacity starts much earlier, decreased myocardial ischemia might not be a direct effect of neurostimulation but rather be due to a better coronary collateralisation because of an enhanced physical activity of the patients

Dose and dose rate measurements for radiation exposure scenarios in nuclear medicine

Radiation exposure for the staff in nuclear medicine departments is inevitable. After application of radiopharmaceuticals the patient himself becomes a radioactive source. Consequently, we need detailed information on the extent of radiation exposure for each single person dealing with radioactive sources and patients in nuclear medicine. In this work, dose rates of a variety of radioactive sources radiopharmaceuticals and patients in nuclear medicine were investigated. For this purpose different detectors (dosimeters, survey-meters) were used and different sources were measured for several distances between source and detector. The radioactive patient as a source can be considered as uncritical. However, this assumption only holds if members of the personnel keep a sufficient distance to the patient of at least 1 m. If treatments in the vicinity of the patient become necessary, the time spent in a closer distance should be limited. The handling of radiopharmaceuticals often involves close contact to the radioactive source. For the beta-radiation or in the mixed beta,gamma-radiation field of several high energy beta emitters ((32)P, (68)Ga, (90)Y, (188)Re) the ambient dose equivalent rate at 10 mm depth together with the directional dose equivalent rate at 0 degrees and 0.07 mm depth have to be determined. Especially for the beta emitters mentioned above these dose rates are very high. For instance the specific dose rate for (90)Y yields 4.6 Sv/(GBp.h) when dose rate measurements were performed in the closest distance to a glass vial that was practicable. Survey-meters that are only capable of measuring photons fail to provide even a rough approximation of the actual dose rate. Preparations of radiopharmaceuticals with these nuclides may consequently cause a high extremity exposure of laboratory staff. This requires measurements, demands training and a strict compliance with the established radiation safety standards. (C) 2011 Elsevier Ltd. All rights reserved

Intravenous Streptokinase in Acute Myocardial Infarction (I.S.A.M.) trial: Serial evaluation of left ventricular function up to 3 years after infarction estimated by radionuclide ventriculography

AbstractThe Intravenous Streptokinase in Acute Myocardial Infarction (I.S.A.M.) trial was a prospective, placebo-controlled, doubleblind multicenter trial of high-dose short-term intravenous streptokinase in acute myocardial infarction administered within 6 h after the onset of symptoms. Global and regional left ventricular ejection fractions were determined by radionuclide ventriculography in a subset of 120 patients 3 days, 4 weeks, 7 months, 18 months and 3 years after acute myocardial infarction.In patients with anterior myocardial infarction, left ventricular ejection fraction was higher in the Streptokinase than in the placebo group 3 days after acute infarction (49 ± 14% vs. 40 ± 11%, p = 0.02). This difference of about 10% units in ejection fraction persisted during the 3 year follow-up period. Among streptokinase-treated patients, regional left ventricular ejection fraction was higher within the infarct zone as well as in remote myocardium throughout the follow-up period. Among patients with inferior infarction, no significant differences between the treatment and control groups were demonstrable with respect to global and regional left ventricular ejection fraction.Thus, intravenous administration of streptokinase within 6 h after the onset of symptorrs of acute myocardial infarction preserves left ventricular function over a period of ⩾3 years in patients with acute anterior myocardial infarction. It improves regional myocardial function within the infarct zone as well as in remote areas. In patients with acute inferior myocardial infarction, benefit from intravenous Streptokinase is of only minor degree

Exhalation of I-131 after radioiodine therapy: measurements in exhaled air

Purpose A considerable amount of radioiodine is exhaled after radioiodine therapy leading to unwanted radiation exposure through inhalation. This study focused on the concentration of radioactivity exhaled and its chemical nature. Methods Air exhaled by 47 patients receiving I-131-iodine for different thyroid diseases (toxic goitre n=26, Graves' disease n=13, thyroid cancer n=8) was investigated with a portable constant air-flow sampler. Different chemical iodine species were collected separately (organic, elemental and aerosolic) up to 26 h after administration of the radioiodine capsule. The data approximated to a monoexponential time-activity curve when integrated over 100 h. The radioactivity in the filters was measured with a well counter at defined time points after administration. Results The radioactivity of I-131 in the exhaled air 1 h after administration ranged from 1 to 100 kBq/m(3). Two parameters (half-life of radioiodine exhalation and time-integrated activity over 100 h) were substantially higher in patients with cancer after near-total thyroidectomy (11.8 +/- 2.1 h and 535 +/- 140 kBq / m(3), respectively) than in patients with hyperfunctioning thyroid tissue due to toxic adenoma (7.6 +/- 2.5 h and 115 +/- 27 kBq / m(3), respectively) or Graves' disease (6.4 +/- 3.6 h and 113 +/- 38 kBq / m(3), respectively). The percentage of radioiodine in the exhaled air in relation to radioiodine administered to the patient was between 80 ppm and 150 ppm. The fraction of organically bound radioiodine (mean value) for all time points after administration was 94-99.9%. This percentage did not depend on the type of thyroid disease. Conclusion The amount of exhaled radioiodine is small but by no means negligible on the first day after administration. This is the first study to provide experimental evidence on a systematic basis that radioiodine becomes exhalable in vivo, i.e. in the patient. The mechanism of organification of orally administered radioiodine remains to be investigated