Incidence of thrombotic events and complications associated to inferior vena cava filters in patients with and without anticoagulation therapy / Incidencia de eventos trombóticos y complicaciones asociadas al uso de filtros de vena cava en pacientes en pacientes con o sin terapia anticoagulante

Abstract Objective: Anticoagulation is the primary management to prevent venous thromboembolism; inferior vena cava filters (IVCFs) provide a mechanical prophylactic alternative when anticoagulation is contraindicated. The aim of this study was to evaluate in IVCF patients, whether the initiation of anticoagulation therapy is associated with decreased rates of recurrent thrombotic events and device-related complications. Methods: This was a retrospective review of patients that underwent insertion of IVCF. Subjects with IVCF were studied in two groups: those initiated on anticoagulation (A) and without anticoagulation (NA). Variables as indications for IVCF, anticoagulation, recurrence of thrombosis, complications, and reinterventions were examined. Results: From April 2007 to March 2014, 54 patients underwent IVCF placement; (61% of females), with mean age of 54 years (standard deviation ± 19). 28 (52%) were initiated on anticoagulation, during a mean follow-up period of 28 months, five experienced recurrent thrombosis and three were on the A group (p=0.5); when comparing patients that developed post-thrombotic syndrome, seven were in the A group and seven in the NA. Two patients with IVC rupture were in the A group (p=0.5), and the only case of IVCF migration occurred in the A group. 11 (20%) patients died from comorbidities nonrelated to the device or procedure (four in the A cohort). Conclusions: Patients with IVCF on anticoagulation have equivalent rates of thrombotic events and device-related complications than those patients NA.

Resumen Objetivo: La anticoagulación es la terapia de elección para la prevención de tromboembolismo venoso; los filtros de vena cava inferior (FVCI) proveen una alternativa mecánica profiláctica cuando la anticoagulación está contraindicada. El objetivo de este estudio fue evaluar si la terapia anticoagulante se asocia con una tasa menor de eventos trombóticos recurrentes y complicaciones relacionadas con el dispositivo. Métodos: Los pacientes fueron categorizados en dos grupos: Aquellos a los que se les inicio anticoagulación (A) y aquellos que no (NA). Variables tales como indicación de la colocación del filtro, anticoagulación, recurrencia de trombosis y complicaciones fueron examinadas. Resultados: De abril de 2007 a marzo 2014, a 54 pacientes se les coloco un filtro (61% fueron mujeres), con una media de edad de 54 años [Desviación estándar (DE) ±19. Veintiocho (52%) fueron iniciados en anticoagulación y durante un seguimiento de 28 meses, 5 pacientes experimentaron recurrencia de trombosis, 3 en el grupo A (p=0.5). Al comparar los pacientes que desarrollaron síndrome posflebítico, 7 pertenecieron al grupo A y 7 al grupo NA. Dos pacientes con ruptura de vena cava pertenecieron al grupo A (p=0.5) y el único caso de migración del dispositivo ocurrió en el grupo A. Once (20%) pacientes fallecieron debido a comorbilidades no relacionadas con el dispositivo o el procedimiento. Conclusión: Pacientes con FVCI en anticoagulación tienen tasas de eventos trombóticos y complicaciones asociadas a los dispositivos equivalentes a aquellos pacientes sin anticoagulación.

Radiopaque nano and polymeric materials for atherosclerosis imaging, embolization and other catheterization procedures

A review of radiopaque nano and polymeric materials for atherosclerosis imaging and catheterization procedures is presented in this paper. Cardiovascular diseases (CVDs) are the leading cause of death in the US with atherosclerosis as a significant contributor for mortality and morbidity. In this review paper, we discussed the physics of radiopacity and X-ray/CT, clinically used contrast agents, and the recent progress in the development of radiopaque imaging agents and devices for the diagnosis and treatment of CVDs. We focused on radiopaque imaging agents for atherosclerosis, radiopaque embolic agents and drug eluting beads, and other radiopaque medical devices related to catheterization procedures to treat CVDs. Common strategies of introducing radiopacity in the polymers, together with examples of their applications in imaging and medical devices, are also presented.

Inferior vena cava filters in pulmonary embolism: A historic controversy / Filtros de vena cava inferior en tromboembolia pulmonar: Una controversia histórica

Abstract: Objective: Rationale for non-routine use of inferior venous cava filters (IVCF) in pulmonary embolism (PE) patients. Methods: Thrombosis mechanisms involved with IVCF placement and removal, the blood-contacting medical device inducing clotting, and the inorganic polyphosphate in the contact activation pathway were analyzed. In addition, we analyzed clinical evidence from randomized trials, including patients with and without cancer. Furthermore, we estimated the absolute risk reduction (ARR), the relative risk reduction (RRR), and the number needed to treat (NNT) based on the results of each study using a frequency table. Finally, we analyzed the outcome of our PE patients that were submitted to thrombolysis with short and long term follow-up. Results: IVCF induces thrombosis by several mechanisms including placement and removal, rapid protein adsorption, and simultaneous surface-induced activation via the contact activation pathway. Also, inorganic polyphosphate has an important role as a procoagulant, reversing the effect of anticoagulants. Randomized control trials included 904 cancer and non-cancer PE patients. In terms of ARR, RRR, and NNT, there is no evidence for routine use of IVCF. In 290 patients with proved PE, extensive thrombotic burden and right ventricular dysfunction under thrombolysis and oral anticoagulation, we observed a favorable outcome in a short- and long-term follow-up; additionally, IVCF was only used in 5% of these patients. Conclusion: Considering the complex mechanisms of thrombosis related with IVCF, the evidence from randomized control trials and ARR, RRR, and NNT obtained from venous thromboembolism patients with and without cancer, non-routine use of IVCF is recommended.

Resumen: Objetivo: Racionalidad para no utilizar en forma rutinaria filtros de vena cava inferior (FVCI) en pacientes con tromboembolia pulmonar (TEP). Métodos: Analizamos mecanismos de trombosis relacionados con la colocación o retiro de estos dispositivos médicos, incluyendo la importancia del polifosfato inorgánico en la vía de activación de contacto. Analizamos evidencia clínica de estudios aleatorizados controlados en pacientes con y sin cáncer. Mediante tablas de frecuencia estimamos de cada estudio reducción del riesgo absoluto (RRA) y relativo (RRR) y el número necesario a tratar (NNT). Finalmente, examinamos la evolución de nuestros pacientes con TEP llevados a trombolisis con seguimientos a corto y largo plazo. Resultados: FVCI inducen trombosis por diferentes mecanismos: colocación y retiro, adsorción rápida de proteínas y activación de superficie inducida en la vía de activación de contacto. El polifosfato inorgánico es un procoagulante importante para la anticoagulación. Estudios aleatorizados controlados incluyeron 904 pacientes con TEP con y sin cáncer. En términos de RRA, RRR y NNT no existe evidencia para el uso rutinario. En 290 pacientes con TEP probada, importante carga de trombo y disfunción del ventrículo derecho llevados a trombolisis y anticoagulación observamos una evolución favorable en seguimientos a corto y largo plazo. En estos pacientes los FVCI se utilizaron solo en el 5%. Conclusión: Considerando los mecanismos complejos de trombosis relacionados con los FVCI, la evidencia obtenida de los estudios aleatorizados y controlados, así como la RRA, RRR y NNT en pacientes con tromboembolismo venoso con y sin cáncer, no recomendamos el uso rutinario de FVCI.

Long-term follow-up of inferior vena cava filters in conjunction with thrombolysis and anti-coagulant therapy in prevention of pulmonary embolism in patients with deep vein thrombosis / 中国介入心脏病学杂志

Objective To analyze retrospectively long term follow up of inferior vena cava filters in conjunction with thrombolysis and anti coagulant therapy in prevention and treatment of pulmonary embolism (PE) in 24 patients with deep vein thrombosis (DVT) Methods This study included 13 males and 11 females with an average age of 52 4 years (14-86 years) Percutaneous implantation of inferior vena cava filters was performed via a femoral vein in 24 patients with acute or subacute DVT, of whom two were given conjunctive catheter based urokinase thrombolysis After the procedure, 20 patients underwent intravenous urokinase thrombolysis with subcutaneous low weight molecular heparin for 10 days and subsequent oral warfarin for six months Results All patients underwent a successful interventional procedure with an average 15 month (10-48 months) follow up One week after the procedure, relief of symptoms related to DVT was achieved in all the 24 patients Neither filter migration and thrombolic occlusion of filter nor PE and major hemorrhage were observed in this series Conclusion The use of inferior vena cava filters in conjunction with thrombolysis and anti coagulant therapy is a safe and effective treatment modality in patients with DVT, which can be used to prevent subsequent PE