El regadenosón como nuevo agente de estrés para la adquisición de imágenes SPECT de perfusión miocárdica. Experiencia inicial en Holanda / Regadenoson as a new stress agent in myocardial perfusion imaging. Initial experience in The Netherlands

Objetivo. El regadenosón es un agonista selectivo para los receptores adenosínicos-2A recién aprobado para inducir estrés farmacológico con una sola inyección en bolo para la adquisición de imágenes SPECT de perfusión miocárdica (IPM). Material y Métodos. Se incluyeron 123 pacientes sucesivos referidos para IPM por sospecha de enfermedad arterial coronaria (EAC). A 66 pacientes se les hizo una prueba de estrés con regadenosón y a 57 con adenosina, ambas seguidas por SPECT de manera estándar. A los técnicos, médicos y los pacientes mismos se les pidió que reportaran sus experiencias mediante cuestionarios. Resultados. En comparación con la adenosina, el regadenosón no produjo ningún bloqueo auriculoventricular (frente al 10% tras adenosina), pero produjo una taquicardia menor y cambios de la presión arterial pequeños. Todos los síntomas tras el regadenosón fueron más leves y de duración más corta. Hubo menos pacientes que tenían síntomas graves tras el regadenosón (17% vs. 32%, p < 0,01). El efecto secundario reportado más frecuentemente fue la disnea, seguido por rubefacción y angina, pero todos estos efectos se resolvieron rápidamente. La puntuación global de los síntomas, que incluye tanto la severidad como la duración, fue significativamente más baja después del regadenosón que después de la adenosina (6,7 ± 6,3 vs. 10,0 ± 7,9, respectivamente, p < 0,01). Las imágenes SPECT fueron similares. El procedimiento con el regadenosón fue más rápido y práctico. Conclusión. El regadenosón es un nuevo agente de estrés conveniente para IPM con un perfil muy favorable para los pacientes y los departamentos de cardiología nuclear (AU)

Objective. Regadenoson is a recently approved selective adenosine-2A receptor agonist to induce pharmacological stress in myocardial perfusion imaging (MPI) procedures using a single bolus injection. Material and Methods. We included 123 patients referred for MPI because of suspected coronary arterial disease (CAD). Of these, 66 patients underwent a regadenoson stress test and 57 patients underwent an adenosine stress test preceding standard myocardial SPECT imaging. Technicians, physicians and patients were asked to report their experience using questionnaires. Results. As compared to adenosine, regadenoson did not produce any atrio-ventricular block (0 vs. 10% with adenosine), but did produce minor tachycardia and minimal blood pressure changes while all other side effects were milder and shorter. There were fewer patients with severe complaints after taking regadenoson than adenosine (17% vs. 32%, respectively, p < 0.01). The most frequent complaint reported was dyspnea, followed by flushing and chest pain. However, when they did occur, they usually disappeared rapidly. The overall symptom score, including severity and duration of side effects, was significantly lower after regadenoson than after adenosine (6.7 ± 6.3 vs. 10.0 ± 7.9, respectively; p < 0.01.) SPECT imaging results were similar. The regadenoson procedure was faster and more practical. Conclusion. Regadenoson, the new selective adenosine-2A receptor agonist, is a stress agent for MPI with a patient- and department friendly profile (AU)

[Regadenoson as a new stress agent in myocardial perfusion imaging. Initial experience in The Netherlands]. / El regadenosón como nuevo agente de estrés para la adquisición de imágenes SPECT de perfusión miocárdica. Experiencia inicial en Holanda.

OBJECTIVE: Regadenoson is a recently approved selective adenosine-2A receptor agonist to induce pharmacological stress in myocardial perfusion imaging (MPI) procedures using a single bolus injection. MATERIAL AND METHODS: We included 123 patients referred for MPI because of suspected coronary arterial disease (CAD). Of these, 66 patients underwent a regadenoson stress test and 57 patients underwent an adenosine stress test preceding standard myocardial SPECT imaging. Technicians, physicians and patients were asked to report their experience using questionnaires. RESULTS: As compared to adenosine, regadenoson did not produce any atrio-ventricular block (0 vs. 10% with adenosine), but did produce minor tachycardia and minimal blood pressure changes while all other side effects were milder and shorter. There were fewer patients with severe complaints after taking regadenoson than adenosine (17% vs. 32%, respectively, p<0.01). The most frequent complaint reported was dyspnea, followed by flushing and chest pain. However, when they did occur, they usually disappeared rapidly. The overall symptom score, including severity and duration of side effects, was significantly lower after regadenoson than after adenosine (6.7±6.3 vs. 10.0±7.9, respectively; p<0.01.) SPECT imaging results were similar. The regadenoson procedure was faster and more practical. CONCLUSION: Regadenoson, the new selective adenosine-2A receptor agonist, is a stress agent for MPI with a patient- and department friendly profile.

Synthetic analogues of the antithrombin III-binding pentasaccharide sequence of heparin. Prediction of in vivo residence times.

The synthetic pentasaccharide Org 31540/SR 90107A represents the antithrombin III (ATIII) binding region of heparin and accelerates the ATIII-mediated inhibition of coagulation factor Xa. This compound and 15 structural analogues with ATIII binding constants (Kd) ranging from 2.7 to 2600 nmol/L were compared for their plasma elimination in rats as measured from their factor Xa inhibiting activity. After administration of a low dose (100 nmol/kg body wt IV), each pentasaccharide showed a characteristic plasma half-life varying from a minimum of 0.3 hour for pentasaccharides with low affinity for ATIII to 10.9 hours for pentasaccharides with high affinity for the protein. The latter value was close to the half-life measured for radioiodinated rat ATIII (11.8 hours). We hypothesized that the elimination half-life of pentasaccharides is markedly extended by ATIII binding, of which the extent is governed by the Kd of the complex. The following observations support this hypothesis. The low-dose, low-affinity pentasaccharides were almost fully recovered in the urine without having lost anti-factor Xa activity, whereas compounds with high ATIII binding affinity were only partly recovered in the urine. With a high dose (500 nmol/kg body wt), a rapid plasma clearance of pentasaccharide was observed until a concentration similar to that of endogenous ATIII was reached, in accordance with their expected 1:1 stoichiometric interaction. The elimination of half-life was similar to that of the low dose. The relation between Kd values and plasma half-lives could be explained by assuming rapid clearance of free and coclearance of ATIII-bound pentasaccharide with the protein.(ABSTRACT TRUNCATED AT 250 WORDS)