Combined subcutaneous and high-dose intravenous deferoxamine therapy of thalassemia.

Although the preliminary findings are encouraging, to assess the effectiveness of the SHYD program on the long-term course of thalassemia, a larger patient population and longer treatment and follow-up period are needed. The presence of cardiac abnormalities in patients in Group I suggests that to prevent heart damage in thalassemia, it may be necessary to start the HTP and effective chelation therapy at a very young age, realizing that the amount of iron removed will be small. The finding that two of the four patients who survived to receive the largest amount of Fe/kg have intact spleens and another had splenectomy at age 24 suggests that, in these patients, the spleen may have had a protective role for the heart. If this observation is confirmed, it would provide evidence that removal of the spleen may adversely affect the long-term course of patients with thalassemia. Six years' experience with the SHYD program has not provided evidence for significant acute or chronic toxicity. This suggests that it might be safe to administer the i.v. treatments at home, a program that is anticipated for the future, as it would significantly reduce cost and possibly be more convenient.

The cardiovascular effects of metrizamide in infants.

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.

Precordial contrast echocardiographic detection of patent ductus arteriosus in small preterm infants.

Clinical detection of patent ductus arteriosus (PDA) remains an important and challenging problem in the small preterm infant with respiratory distress. In this study, PDA was diagnosed in 28 small preterms using an improved contrast echocardiographic method. In these infants, the injection of saline into the aorta generated echoes which were imaged at the pulmonary valve. This was accomplished using a conventional M-mode ultrasound transducer applied at the usual precordial position. Contrast echo studies were compared with the degree of ductal patency shown by single film aortography. Ductal patency was detected by contrast echo in 29 of 31 instances of aortographically proven PDA. Indirect echo indices commonly used for detection of PDA (cardiac chamber enlargement) may be limited since factors other than left-to-right shunt can cause cardiac enlargement in distressed small preterms. This direct contrast echo technique is an easily performed, sensitive, qualitative method for confirmation of the diagnosis of PDA in small preterm infants.