[Treatment of pulmonary vein stenosis secondary to radiofrequency ablation]. / Tratamiento de estenosis de venas pulmonares secundaria a ablación por radiofrecuencia.

Isolation of the pulmonary veins by applying radiofrequency is an effective treatment for atrial fibrillation. One of the potential complications with higher clinical compromise utilizing this invasive technique is the occurrence of stenosis of one or more pulmonary veins. This complication can be treated by angioplasty with or without stent implantation, with an adequate clinical improvement, but with a high rate of restenosis.

Tratamiento de estenosis sintomática de venas pulmonares secundaria a ablación por radiofrecuencia

El aislamiento de las venas pulmonares mediante la aplicación de radiofrecuencia es un tratamiento efectivo de la fibrilación auricular. Una de las complicaciones potenciales y de mayor compromiso clínico de esta técnica invasiva es la estenosis de una o varias venas pulmonares. Esta complicación puede ser tratada mediante angioplastia con o sin colocación de stent, logrando una adecuada mejoría clínica, aunque con un alto índice de recurrencia por re-estenosis.

Isolation of the pulmonary veins by applying radiofrequency is an effective treatment for atrial fibrillation. One of the potential complications with higher clinical compromise utilizing this invasive technique is the occurrence of stenosis of one or more pulmonary veins. This complication can be treated by angioplasty with or without stent implantation, with an adequate clinical improvement, but with a high rate of restenosis.

Tratamiento de estenosis sintomática de venas pulmonares secundaria a ablación por radiofrecuencia

El aislamiento de las venas pulmonares mediante la aplicación de radiofrecuencia es un tratamiento efectivo de la fibrilación auricular. Una de las complicaciones potenciales y de mayor compromiso clínico de esta técnica invasiva es la estenosis de una o varias venas pulmonares. Esta complicación puede ser tratada mediante angioplastia con o sin colocación de stent, logrando una adecuada mejoría clínica, aunque con un alto índice de recurrencia por re-estenosis.(AU)

Isolation of the pulmonary veins by applying radiofrequency is an effective treatment for atrial fibrillation. One of the potential complications with higher clinical compromise utilizing this invasive technique is the occurrence of stenosis of one or more pulmonary veins. This complication can be treated by angioplasty with or without stent implantation, with an adequate clinical improvement, but with a high rate of restenosis.(AU)

Tratamiento de estenosis de venas pulmonares secundaria a ablación por radiofrecuencia. / [Treatment of pulmonary vein stenosis secondary to radiofrequency ablation].

Isolation of the pulmonary veins by applying radiofrequency is an effective treatment for atrial fibrillation. One of the potential complications with higher clinical compromise utilizing this invasive technique is the occurrence of stenosis of one or more pulmonary veins. This complication can be treated by angioplasty with or without stent implantation, with an adequate clinical improvement, but with a high rate of restenosis.

Protection of Distal Embolization in High-Risk Patients with Acute ST-Segment Elevation Myocardial Infarction (PREMIAR).

Distal embolization may decrease myocardial reperfusion after primary percutaneous coronary intervention (PCI). Nonetheless, results of previous trials assessing the role of distal protection during primary PCI have been controversial. The Protection of Distal Embolization in High-Risk Patients with Acute ST-Segment Elevation Myocardial Infarction Trial (PREMIAR) was a prospective, randomized, controlled study designed to evaluate the role of filter-based distal protection during PCI in patients with acute ST-segment elevation myocardial infarction at high risk of embolic events (including only baseline Thrombolysis In Myocardial Infarction grade 0 to 2 flow). The primary end point was continuous monitoring of ST-segment resolution. Secondary end points included core laboratory analysis of angiographic myocardial blush, ejection fraction measured by cardiac ultrasound, and adverse cardiac events at 6 months. From a total of 194 enrolled patients, 140 subjects were randomized to PCI with or without embolic protection, and 54 were included in a registry arm due to the presence of angiographic exclusion criteria. Baseline characteristics were comparable between arms. The rate of complete ST-segment resolution (>or=70%) at 60 minutes was similar in patients treated with or without distal protection (61.2% vs 60.3%, respectively, p = 0.85). Angiographic myocardial blush (67% vs 70.7%, p = 0.73), in-hospital ejection fraction (47.4 +/- 9.9% vs 45.3 +/- 7.3%, p = 0.29), and combined end point of death, heart failure, or reinfarction at 6 months (14.3% vs 15.7%, p = 0.81) were consistently achieved in a similar proportion in the 2 groups. In conclusion, the use of filter-based distal protection is safe and effectively retrieves debris; however, such use does not translate into an improvement of myocardial reperfusion, left ventricular performance, or clinical outcomes.

Multicenter randomized comparison of direct vs. conventional stenting: the DIRECTO trial.

With conventional stenting, predilatation frequently induces dissections that require deploying stents longer than originally planned. To assess whether direct stenting is safe and may prevent dissections and reduce the length of stents implanted, we conducted a randomized study comparing direct (n = 73) and conventional (n = 78) stenting. Direct stenting was successful in 89% of cases, 11% crossed over to predilation without complications. Dissections occurred more frequently in conventional stenting group (10.3% vs. 1.4%; P = 0.034), but did not translate to a significant stent length difference (16.31 +/- 7.6 vs. 15.31 +/- 5.5; P = NS). Periprocedure creatine kinase elevation and number of balloons utilized were lower with direct stenting.

Estudios experimentales / Experimental studies

El estudio randomizado doble ciego es el dise±o de elección para la investigación clínica. Permite inferir si existe una relación causal entre la intervención aplicada y el efecto producido, y es ideal para valorar la eficacia de programas de tratamiento. La randomización elimina el sesgo producido por confounding variables (caracteristicas basales de los pacientes que pueden influir sobre el resultado del estudio).El desconocimiento por parte de los investigadores y pacientes del tratamiento asignado, previene los sesgos que se producen durante la evaluación y adjudicación de eventos. En este capitulo describimos los pasos a seguir en el dise±o de un estudio prospectivo randomizado doble ciego y repasaremos brevemente otros dise±os de estudios experimentales utilizados con menor frecuencia. SUMMARY: The best experimental desing for clinical investigation is the prospective randomized blinded trial. This desing offers strength in causal inference and therefore is specially suited for testing the efficacy of treatment programs. Randomization eliminates bias due to preparandomization confounding variables, and blinding of intervention eliminates bias in the evaluation and adjudication for events. In the following chapter we will provide a guide for designing a prospective randozimed double blind study and will briefly review other experimental study designs used less frequently

Estudios experimentales / Experimental studies

El estudio randomizado doble ciego es el dise±o de elección para la investigación clínica. Permite inferir si existe una relación causal entre la intervención aplicada y el efecto producido, y es ideal para valorar la eficacia de programas de tratamiento. La randomización elimina el sesgo producido por confounding variables (caracteristicas basales de los pacientes que pueden influir sobre el resultado del estudio).El desconocimiento por parte de los investigadores y pacientes del tratamiento asignado, previene los sesgos que se producen durante la evaluación y adjudicación de eventos. En este capitulo describimos los pasos a seguir en el dise±o de un estudio prospectivo randomizado doble ciego y repasaremos brevemente otros dise±os de estudios experimentales utilizados con menor frecuencia. SUMMARY: The best experimental desing for clinical investigation is the prospective randomized blinded trial. This desing offers strength in causal inference and therefore is specially suited for testing the efficacy of treatment programs. Randomization eliminates bias due to preparandomization confounding variables, and blinding of intervention eliminates bias in the evaluation and adjudication for events. In the following chapter we will provide a guide for designing a prospective randozimed double blind study and will briefly review other experimental study designs used less frequently