17-iodoheptadecanoic-acid and Angina-Pectoris

The results described in the literature of myocardial scintigraphy with radioiodinated heptadecanoic acid (IHDA) to detect coronary stenoses are contradictory. In the present study, IHDA scintigraphy was performed in nine control subjects and 67 patients with coronary artery disease. The acquisition time was 75 min and background correction was not applied. The time-activity curves of regions of interest were analyzed by curve fitting with a monoexponential plus constant. Two parameters were used: the halftime value of the monoexponential (T1/2 in min) and the ratio of the amplitude (A) of the monoexponential and the total activity at time t = 0 (amplitude + constant = A + C): A/A + C as a percentage. Based on the control group, a region of normal T1/2 values and A/A + C ratios was defined, for each calculated T1/2-A/A + C pair the probability of originating from a normal region was calculated. The value of the IHDA test, using the index of merit (sensitivity + specificity-100%), increased in the patient group without MI with the severity of the stenosis (21%, 24% and 47% for stenoses greater than or equal to 75%, greater than or equal to 90% and greater than or equal to 99%). In patients with MI, only small positive values in regions of non-infarct-related vessels were found (-1%-16%). It is concluded that the value of the IHDA test to detect stenoses of coronary arteries is too low to apply this test in clinical practice. However, a new type of analysis is offered, based on curve fitting of individual pixels.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Angina Pectoris; Fatty Acids; Humans; Iodine Radioisotopes; Myocardial Infarction; Myocardium; Radionuclide Imaging

On the basis of the results which we obtained having performed 25 examinations on 15 patients with angina pectoris syndrome, myocardial infarctions and condition after bypass operation the preparation 123I hepatadecanoic acid produced in the Central Institute for Nuclear Research Rossendorf is very well suited for the scintigraphic demonstration of the myocardium. Moreover it is possible to recognize selectively diagnostically interesting regions with different radioactivity intake, retention and elimination of the radiopharmacon pharmacon and with the help of quantitative parameters to characterize concerning the metabolic efficiency. We consider the 123I hepatadecanoic acid suitable for the clinical use in establishing the global and regional metabolic efficiency of the myocardium. It is very well to be used for the primary diagnostics and represents an evident diagnostic remedy for the assessment of the course of myocardial diseases and the success of therapy.

Topics: Adult; Aged; Angina Pectoris; Cardiac Output; Coronary Artery Bypass; Fatty Acids; Humans; Middle Aged; Myocardial Contraction; Myocardial Infarction; Postoperative Complications; Radionuclide Imaging

Calculation of metabolic turnover rates with 123I-heptadecanoic acid (123I-HA) can detect regional myocardial ischaemia in patients with coronary artery disease. We have previously demonstrated different turnover rates in patients with stable angina compared with myocardial infarction. Twelve patients with unstable angina have now been studied: 8 patients showed imaging defects in 12 different myocardial regions and in 4 no defects were observed. Turnover rates were derived from time-activity curves and expressed in minutes half-time (t 1/2). All 12 regions with accumulation defects showed increased t 1/2 values (45.4 +/- 4.8 min) compared to normally perfused zones (29.1 +/- 3.6 min). The results suggest that the use of 123I-HA can identify ischaemic areas of myocardium in unstable angina and that the turnover of 123I-HA is different from that already established in the areas with infarction.

Topics: Angina Pectoris; Angina, Unstable; Fatty Acids; Female; Heart; Humans; Iodine Radioisotopes; Male; Middle Aged; Myocardium; Radionuclide Imaging

The potential value of 123I-heptadecanoic acid (123I-H degree A) in myocardial scintigraphy has recently been assessed in patients with acute myocardial infarction (AMI) by studying regional myocardial metabolism (Van der Wall et al. 1981 a). To determine the metabolic behavior of 123I-H degree A in patients with stable angina pectoris (AP) as well, 30 patients with AP were included in this study: 18 patients were exercised and 12 patients were studied at rest. Regional myocardial metabolism was evaluated by generating background subtracted time-activity curves, acquired by external detection over normally perfused and ischemic regions during a 30-min period after intravenous injection of 123I-H degree A. Following monoexponential curve-fitting, clearance rates were measured representing turnover rate (T1/2) of 123I-H degree A. The exercise group showed prolonged T1/2 values of 46.7 +/- 7.1 min (mean +/- SD) in ischemic regions and 28.7 +/- 3.6 min in normally perfused regions. The group at rest did not reveal any scintigraphic abnormalities and showed normal T1/2 values in all myocardial regions (29.1 +/- 4.7 min). Our observations of prolonged turnover rates in ischemic areas differ from the results of our recent study in patients with AMI, which demonstrated fast turnover rates in infarcted tissue. These data imply that 123I-H degree A permits the study of myocardial metabolism in patients with AP and the discrimination of normally perfused, reversibly ischemic (AP) and irreversibly ischemic (AMI) myocardium.

Topics: Adult; Aged; Angina Pectoris; Coronary Angiography; Exercise Test; Fatty Acids; Heart; Humans; Iodine Radioisotopes; Male; Middle Aged; Radionuclide Imaging