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To determine if radiocontrast impairs vascular relaxation of the renal artery, segments (4-5 mm in length) of canine renal artery were suspended in vitro in organ chambers to measure isometric force (95% O2/5% CO2, at 37 C). Arterial segments with and without endothelium were placed at the optimal point of their length-tension relation and incubated with 10 microM indomethacin to prevent synthesis of endogenous prostanoids. The presence of nonionic radiocontrast (iohexol, Omnipaque 350, 1 ml in 25 ml control solution, 4% (v/v)) did not alter endothelium-dependent relaxation to acetylcholine in rings precontracted with both norepinephrine and prostaglandin F2alpha (N = 6). When the rings were precontracted with prostaglandin F2alpha, the presence of ionic contrast did not inhibit the relaxation of the arteries. However, in canine renal arteries contracted with norepinephrine, the presence of ionic radiocontrast (diatrizoate meglumine and diatrizoate sodium, MD-76, 1 ml in 25 ml control solution, 4% (v/v)) inhibited relaxation in response to acetylcholine, sodium nitroprusside (N = 6 in each group), and isoproterenol (N = 5; P < 0.05). Rings were relaxed less than 50% of norepinephrine contraction. Following removal of the contrast, vascular relaxation in response to the agonists returned to normal. These results indicate that ionic radiocontrast nonspecifically inhibits vasodilation (both cAMP-mediated and cGMP-mediated) of canine renal arteries contracted with norepinephrine. This reversible impairment of vasodilation could inhibit normal renal perfusion and act as a mechanism of renal failure following radiocontrast infusion. In the adopted experimental protocol the isoproterenol-induced relaxation of renal arteries precontracted with norepinephrine was more affected, suggesting a pivotal role of the cAMP system.

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Objetivo: Determinar cual de los medios de contraste (MC) iónicos producía con mayor frecuencia y gravedad de reacciones adversas (RA) en la urografía excretora(UE),en el Hospital Roosevelt,Guatemala, desde abril de 1996 a febrero de 1997.Material y Métodos: Se realizó un estudio prospectivo seleccionando a 200 pacientes sometidos a UE, que fueron divididos en cuatro grupos(cada uno con n=50),según el MC yodado, hidrosoluble, iónico y alta osmolaridad administrado por vía intravenosa (IV) en dosis de 80 a 100 ml:1) iodamida,2) ioxitalamato,3), amidotrizoato y 4)diatrizoato. Se incluyeron pacientes mayores de 12 años, ambulatorios u hospitalizados, sin antecedentes de RA a los MC, asma, sensibilización al yodo y sin insuficiencia cardíaca congestiva. Se clasificacon las RA en leves, moderadas y graves, según la Organización Mundial de la Salud. Se estabaleció el puntaje de gravedad(PG):RA leve=2,RA moderada=4 y RA grave=8; el PG total(PGT) y el PG promedio (PGP). La gravedad se dividió en baja, intermedia y alta. Se usó distribución de frecuencias en porcentajes y chi cuadrado con p menor o igual de 0,05(5/100). Resultados: La frecuencia de RA fue de 31/100. Leves el 93/100, las moderadas el 7/100 y no hubo graves. El 38/100 de los pacientes con iodamida tuvo RA.La frecuencia de RA de los MC tuvo un valor de p=0,713.El amidotrizoato tuvo el PGP m s alto (4,4); el ioxitalamato tuvo el PGP mas bajo (3,3). El 54/100 de los pacientes tuvo gravedad baja y el 46/100 tuvo intermedia. Discusión: La frecuencia de RA a los MC iodamida, ioxitalamato, amidotrizoato y diatrizoato en la UE fue alta, mayor que lo reportado y sin diferencias importantes entre ellos.Las RA leves fueron muy frecuentes y las moderadas raras. La ausencia de RA graves indica la seguridad de los MC. No hubo diferencias importantes en la gravedad. El PG valoró con objetividad la gravedad de las RA a los MCiónicos usados en UE

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Transient vagal bradycardia occurring during coronary arteriography (CA) immediately following intracoronary injection of ionic contrast medium is believed to be a component of the von Bezold-Jarisch reflex (BJ). Data obtained from experimental animals using buspirone (BSP) and other 5-HT1A receptor ligands suggest that these serotonergic receptors modulate the excitability of cardiac vagal motoneurones (CVM). This is a preliminary investigation of the possible effects of BSP in altering the bradycardia of patients submitted to CA for diagnostic purposes. Patients were divided into two age- and race-matched groups: control (C:N = 45, age 58.6 +/- 1.6 years, mean arterial blood pressure (MAP) 109 +/- 2.4 mmHg, heart rate (HR) 79 +/- 2.9 bpm) and BSP-treated (B:N = 14, age 58.9 +/- 2.1 years, MAP 111 +/- 4.5 mmHg, HR 76 +/- 3.4 bpm). The prevalent underlying pathology was coronary artery disease. Patients with acute angina, congestive heart failure, symptomatic arrhythmia and patients requiring atropine were excluded. CA was performed by a standard procedure using diatrizoate (MD-76) as contrast agent. The left and then the right coronary ostia were selectively catheterized and 8 ml of contrast medium was injected (over a period of 3 sec). HR was measured from ECG tracings before and after contrast injection into the left (LC) and right (RC) coronary arteries. Peak bradycardia was measured as the longest R-R interval during the first 15 sec after the injection minus the pre-injection R-R value, and reported as delta R-R. Group B patients received BSP tablets 48 and 24 h before the examination (30 mg/day po). There was no statistically significant difference (P > 0.05) in bradycardia between groups (C:LC = -147 +/- 23, RC = -155 +/- 25; B: LC = -143 +/- 44, RC = -234 +/- 56 msec). These results suggest that, in contrast to experimental animals, the central 5-HT1A receptors of humans are not relevant for modulating the excitability of CVM in the BJ reflex. However, since drugs and diseases can affect the responses, further studies are necessary to clarify this issue.

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A case of rhabdomyolysis associated with an iodinated contrast medium (sodium diatrizoate) in a patient with chronic renal failure is presented for the purpose of discussing this association. Clinical manifestations were: diffuse myalgias, proximal muscular weakness and an acute reversible deterioration of the renal function. Muscle biopsy showed the typical pattern found in rhabdomyolysis, that is, cellular necrosis with no inflammation signs and myolytic areas. The temporal association between the rhabdomyolysis and the use of the contrast medium suggests a causal relationship. The present case allows us to postulate that the skeletal muscle injury was secondary to direct toxicity and/or the compromise of muscle blood perfusion by the contrast medium in a susceptible muscle due to previous renal failure. It is suggested that this group of substances should be incorporated to the list of agents capable of causing non traumatic rhabdomyolysis.

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We describe a patient with a longstanding paraplegia who developed spinal myoclonus on 3 different occasions spanning one year, once after an enhanced CT scan and twice after excretory urographies, one of which was also followed by a generalized tonic-clonic seizure. To our knowledge only one case of spinal myoclonus secondary to the administration of intravenous contrast material in a patient with a spinal arteriovenous malformation has yet been reported. Taken together, the findings in these cases suggest that spinal myoclonus following intravenous iodine administration is indicative of an underlying spinal cord lesion.

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We describe a patient with a longstanding paraplegia who developed spinal myoclonus on 3 different occasions spanning one year, once after an enhanced CT scan and twice after excretory urographies, one of which was also followed by a generalized tonic-clonic seizure. To our knowledge only one case of spinal myoclonus secondary to the administration of intravenous contrast material in a patient with a spinal arteriovenous malformation has yet been reported. Taken together, the findings in these cases suggest that spinal myoclonus following intravenous iodine administration is indicative of an underlying spinal cord lesion.

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Se presenta un caso de rabdomiolisis asociado al uso de medio de contraste iodado (diatrizoato de sodio) en un paciente con insuficiencia renal crónica con el propósito de comunicar esta asociación. Sus manifestaciones clínicas fueron mialgias difusas, debilidad muscular y deterioro agudo y reversible de la función renal. La biopsia mostró anormalidades típicas de rabdomiolisis. Se presume que, en este caso, el daño muscular fue secundario a toxicidad directa y/o compromiso crítico del flujo sanguínio muscular por el medio de contraste iodado en un músculo susceptible a la injuria por efecto de la insuficiencia renal. Los medios de contraste iodados deben ser adicionados a la lista de fármacos capaces de provocar rabdomiolisis no traumática, la cual puede ser una complicación más común que lo apreciado

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Se presenta un caso de rabdomiolisis asociado al uso de medio de contraste iodado (diatrizoato de sodio) en un paciente con insuficiencia renal crónica con el propósito de comunicar esta asociación. Sus manifestaciones clínicas fueron mialgias difusas, debilidad muscular y deterioro agudo y reversible de la función renal. La biopsia mostró anormalidades típicas de rabdomiolisis. Se presume que, en este caso, el daño muscular fue secundario a toxicidad directa y/o compromiso crítico del flujo sanguínio muscular por el medio de contraste iodado en un músculo susceptible a la injuria por efecto de la insuficiencia renal. Los medios de contraste iodados deben ser adicionados a la lista de fármacos capaces de provocar rabdomiolisis no traumática, la cual puede ser una complicación más común que lo apreciado (AU)

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Six patients died suddenly following the administration of radio contrast media. All had received the so-called older agents which are being replaced by newer contrast agents, which are characterized by reduced osmolality. Five of the six patients experienced almost immediate difficulty in breathing followed by death.

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