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The cardiovascular effects of metrizamide in infants
Insights
Metrizamide, a low-osmolality contrast agent, offers cardiovascular advantages over diatrizoate in infants. It causes less serum osmolality increase, fewer cardiac dimension changes, and a reduced heart rate challenge during angiography.
Area of Science:
- Pediatric Cardiology
- Radiology
- Pharmacology
Background:
- Conventional ionic contrast agents can induce significant cardiovascular changes in pediatric patients.
- Assessing the safety and efficacy of newer, low-osmolality contrast agents is crucial for vulnerable populations.
Purpose of the Study:
- To compare the cardiovascular effects of metrizamide (nonionic, low-osmolality) versus meglumine sodium diatrizoate (ionic, conventional) in children under 3 years.
- To evaluate hemodynamic and biochemical responses to these contrast agents during angiography.
Main Methods:
- Prospective study involving 30 children under 3 years of age.
- Measurement of left ventricular pressures, heart rate, cardiac dimensions (echocardiography), and blood chemistries before and after contrast injection.
- Comparison of metrizamide and meglumine sodium diatrizoate.
Main Results:
- Serum osmolality significantly increased with diatrizoate but not metrizamide.
- Diatrizoate increased both end-diastolic and end-systolic dimensions; metrizamide did not change end-diastolic dimensions and decreased end-systolic dimensions.
- Both agents increased left ventricular pressures similarly, but diatrizoate caused a greater heart rate increase.
- Radiographic opacification quality was comparable.
Conclusions:
- While intracardiac pressure effects are similar, metrizamide is advantageous in critically ill infants.
- Metrizamide's benefits include a smaller increase in serum osmolality, favorable cardiac dimension changes, and a reduced heart rate challenge.
- Metrizamide may be a safer contrast option for pediatric angiography.
Abstract:
A prospective study was performed in 30 children under 3 years of age to compare the cardiovascular effects of a nonionic contrast material of low osmolality, metrizamide, with those of a conventional ionic contrast material, meglumine sodium diatrizoate. Left ventricular end-diastolic pressure, left ventricular peak systolic pressure, heart rate, echocardiographically obtained end-diastolic and end-systolic dimension, and blood chemistries were obtained before and after angiography. Neither contrast material changed serum sodium, potassium, or creatinine levels. However, serum osmolality rose significantly following injection of diatrizoate, but not metrizamide. Both end-diastolic and end-systolic dimensions increased after diatrizoate injection. However, end-diastolic dimension was unchanged and end-systolic dimension fell after metrizamide infusion. Both contrast materials raised left ventricular peak systolic pressure and left ventricular end-diastolic pressure after injection; the magnitude of these pressure changes was the same for both agents. Heart rate increased with diatrizoate to a significantly greater degree than with metrizamide. There was no difference in the quality of radiographic opacification. It is concluded that although the effects on intracardiac pressures are similar for both contrast materials, metrizamide may be advantageous in the critically ill infant because it causes a smaller increase in osmolality, fewer changes in cardiac dimensions, and a reduced heart rate challenge.