I¹³¹-Labeled Serum Albumin: Its Use in the Study of Cardiac Output and Peripheral Vascular Flow

The Determination of Cardiac Output by the Dilution Method without Arterial Sampling

“…If the observed pool has some later component that comes into the region after the period of primary circulation, the calibration described will be falsely high and the counting rate ratio in equation 3 will not be accurate.…”

“…A LTHOUGH earlier determinations of 14A cardiac output in this laboratory [1][2][3] by the radioisotope dilution method were performed by isolating the flow from a specific artery, such sampling is not required by the general formulation of the method. Since the obviation of the arterial puncture would considerably simplify this measurement clinically, studies have been extended 4-to determine cardiac output by focusing a gamma ray detector externally over the region of the cardiac chambers or great vessels.…”

A New Approach to the Evaluation of Peripheral Vascular Disease Using the Gamma Camera

“…Furthermore the opposite extremity simultaneously acts as a control for the extremity under investigation. This is an advantage of the "comparative" technique as suggested by Maclntyre et al (1952).…”

“…The method introduced by Smith and Quimby (1945) was later modified by Krieger et al (1952) and Maclntyre et al (1952) employing a non-diffusible radiopharmaceutical, ie n, I-labeled human serum albumin Following the intravenous injection of the tracer, an activity-time curve measured over an extremity was obtained They interpreted the rising part of the activity curve as expressing the mixing of radioactivity in plasma, which is very closely related to flow, and suggested that the final height of the plateau is indicative of the volume of the vascular bed The use of a non-diffusible tracer only assesses intravascular blood flow because there is no diffusion to extracellular space and tissues Cuypers et al (1962 and employed a technique similar to that of Mac Intyre and reported that they could not differentiate between normal subjects and patients with occlusive disease under resting conditions The flow values obtained at rest were sometimes even higher in patients with obliterative disease than in normal subjects This is in agreement with a report published by Hess (1956), who obtained similar results using d Plethysmographie technique When Cuypers et al repeated the test during hvperemic reaction following a period of ischemia, they were able to define a time parameter which was used in differentiating between normal and pathologic values They did not succeed, however, in establishing a precise mathematical analysis of blood flow nor did they obtain a consistent correlation between the obtained data and the clinical status.…”

“…In the patients the difference in the plateau level seems to be of less important diagnostic value In theory a lower plateau is thought to be compatible with a reduced vascular volume (see chapter 12 2) Maclntyre et al (1952) as well as Cuypers et al (1962) obtained a lower plateau in cases with serious occlusive disease when utilizing radioiodinated human serum albumin When using a freely diffusible tracer like чч ' 'Technetium-pertechnetate, the decreased plateau is suggestive not only of a reduced vascular volume, but also of a reduced muscular volume of the leg, which might correlate with a certain degree of atrophy of the diseased leg In our material nearly all cases with a plateau difference the plateau was equalized, or the difference became insignificant after successful surgery The surgical treatment in subgroup V (poor run-off) was disappointing In this subgroup only a partial reconstruction was possible in most cases The femoro-popliteal grafting procedures highly depend on the vascular status of the arterial tree distal to the occlusion Many authors have reported high failure rates in grafts of small size, especially when the grafting technique is complicated due to an atheromatous core of the arterial wall at the anastomosing site. High flow rates are probably important in preventing re-thrombosis in the early postoperative course (Terry, 1972;Little, 1968).…”