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[Results of the dye dilution technic in peripheral arteriovenous fistulas and hyperthyroidism]
Insights
Dye dilution curves reveal distinct patterns in hyperthyroidism and arteriovenous fistulas, differing from healthy individuals. Early recirculation is noted in hyperthyroidism, while fistulas show subtle changes, impacting cardiac output assessment.
Area of Science:
- Cardiovascular Physiology
- Diagnostic Imaging Techniques
Context:
- Dye dilution curves (DDC) are utilized to assess cardiac output and circulatory dynamics.
- Arteriovenous fistulas (AVFs) and hyperthyroidism are known to alter hemodynamic parameters.
- Comparison of DDC in pathological states versus healthy subjects provides insights into physiological changes.
Purpose:
- To compare dye dilution curves in patients with arteriovenous fistulas and hyperthyroidism against healthy controls.
- To characterize the specific shapes and features of DDC in these patient groups.
- To evaluate the diagnostic utility of DDC in identifying circulatory alterations.
Summary:
- Dye dilution curves were analyzed in 122 healthy subjects, 35 patients with AVFs, and 22 with hyperthyroidism.
- Hyperthyroidism demonstrated early recirculation, while AVFs showed discrete interruptions in dilution curves, especially when occluded.
- Observed DDC variations included accelerated passage, early recirculation, humps, and asymmetrical shapes, with no distinct differences between AVF and hyperthyroid patients.
Impact:
- DDC analysis can reveal specific hemodynamic alterations associated with hyperthyroidism and AVFs.
- Understanding these DDC patterns aids in differentiating pathological circulatory states.
- Findings contribute to the interpretation of DDC in the context of shunts and altered cardiac function.
Abstract:
Dye dilution curves (DDC) from 35 patients with arteriovenous fistulas and from 22 patients with hyperthyreoidism were performed and compared with results in 122 healthy subjects. In most cases Cardiogreen was injected into an antecubital vein during reactive hyperaemia. On the arterial side, dye concentrations were recorded by ear oximetry. The appearance time was shortened in most cases. During dilution time dye curves were interrupted by an early recirculation in hyperthyreoidism, whereas in 29 patients with haemodialysis fistulas this interruption was discrete and detectable only when compared with results after occlusion of the fistulas. Different shapes of dilution curves were observed: 1. in most cases DDC seemed to be normal or near normal, often with an accelerated indicator passage; 2. DDC with an interruption of the dilution limb by an early recirculation; 3. DDD, showing a hump of the dilution limb; 4. asymmetrical DDC or DDC with a flat shoulder of the dilution limb and without a recirculation wave. Patients with hyperthyreoidism and arteriovenous fistulas had no different shapes of dilution curves. The results are discussed with special reference to the DDC in patients with central left-to-right shunts.