Can you tell me how you create this AVF?

Hola Patricio. ¿Cómo evaluaron la mejoría en la capacidad de ejercicio?

Ru-Jeng Teng

Thanks for your interest.

We created a surgical AVF by making a bridge from the superficial femoral artery to the saphenous vein at the level of the inguinal ligament. Surgical intervention lasted 45 minutes with local anaesthetia during which the patient was under 40% 0xygen with a 96% Hb saturation. One hour after the procedure, Hb saturation with 21% 0xygen was 93% and the patient was sent home the next day. I understand that in the german and american protocol they use a device inserted percutaneously.

Estimado Marcelo:

Agradecido por la pregunta.

La capacidad o mas bien la tolerancia al ejercicio en este paciente fué medida por medio del Test de caminata de 6 minutos. El paciente tenía un rendimiento basal de 300 m (61% del teórico) y mejoró a 425 m (84% del teórico). La calidad de vida se midió con el custionario de Saint George que mejora en 3.88 ptos. el control desu enfermedad se evaluó con el CAT que mejoró de 38 a 21 pptos, mmrc y la función con gasometría, espirometría, CVL y DLCO que no se modificaron. La función hemodinámica se midió con ecocardiografía.

El Indice BODE cayó de 6 a 3 puntos.

Muchas gracias por tu respuesta. ¿Cuánto tiempo transcurrió entre las evaluaciones? Muy interesante el resultado. Nosotros tenemos una experiencia con investigadores de la PUC haciendo entrenamiento interválico de alta intensidad en pacientes EPOC (GOLD II-III)

So, it is like a modified B-T shunt for Tetralogy of Fallot. I am not a cardiologist but will taht affect the peripheral tissue oxygenation?

Yes; it does so in the sense that an AVF causes an increase in mixed venous 0xygen content and therefore arterial blood going out of left ventricle will have a higher Pa02. Because of that 0xygen delivery to peripheral tissues is also increased.

Marcelo:

La evaluación se hizo al mes de realizada la FAV. Es importante decir que en comunicaciones previas, la evaluación se ha hecho a las 12 semanas y por lo tanto, podemos asumir que el efecto de la FAV puede ser progresivo en el tiempo y por lo tanto es posible que al reevaluar al paciente en un tiempo mas alejado el efecto positivo de la FAV será mayor. En efecto, hemos controlado recientemente al paciente (a los 6 meses post intervención) y su Pa02 actual es de 73 mm Hg (97% Sa02) no sintiéndose limitado en su capacidad de ejercicio.

Hola Patricio.

Muy interesante el resultado mostrado. ¿Has pensado solicitar un financiamiento para hacer un estudio piloto? Con mucho gusto podemos ayudar con nuestra experiencia evaluando capacidad de ejercicio con VO2 en estos pacientes. Avísame si te interesa y podemos armar algo muy interesante. Estoy viajando a Palestina a dictar un curso y vuelvo el 10 de agosto por si quieres contactarte ([email protected])

What have been your results so far? I believe you are monitoring the patient. Is there some hope?

I would be thankful for your comments.

Munnir:

Our patient is doing well so far. Indeed he came by last week with a Hb sat of 97% and was started on a formal Rehabilitation Program which had been impossible before because of his poor ex. capacity.

I think this intervention is a usefull one on a limited amount of patients and on the other hand, it can give your patient a bit more time before you "confine him" to traditional oxygen therapy

thank you Patricio. It is indeed a news to me. I hope this turns out to be a good news for many patients with stage 4 COPD. Have you compared this patienta with other patients who are on domiciliary oxygen therapy? do you think this AVF technique is going to be an alternative to domicilliary oxygen therapy in future?

Munir:

I think an AVF could be an alternative to domiciliary oxygen in a very select group of GOLD IV patients: those with a strong limitation to exercise due to hypoxemia with a good response to the addition of oxygen say on 6MWT, without pulmonary hypertension or right ventricular failure for a peripheral AVF can cause pulmonary hypertension (we have demonstrated that effect on patients with end state renal failure on haemodyalisis through AVF), without C02 retention and without peripheral vascular pathology.

At this moment we are planning a multicenter trial in order to answer many questions that are open for instance: Does the positive effect of the procedure lasts long enough to become a viable alternative? Is there really an augmentation on V02 as an effect of the AVF? How can we monitor the adverse secondary effects?

The good thing is that in some patients we can obtain a better quality of life with a procedure that can be reversed if SAE occur.

This is a very interesting therapy which I was not aware of. I have a few questions. I would be grateful if you could help answer them or provide references for me to read. I note that you asked for recent research so I presume there may be some "old" research available.

1. Has research been done on animal models? I'd be grateful for references.

2. A bit more detail about the choice of limb for the fistula(s)

3. Other case reports of patients who have had this treatment outside the trial.

Would you be kind enough to translate

Personally, I find this fascinating and I am interested in what the physiological changes are before and after the procedure. I feel strongly that there are lessons and information in this approach which may help in managing acutely unwell COPD patients in ventilatory failure. Thanks in advance to any contributors.

Lawrence

There are not too many papers referring to the subject. I can address you to the ones I consider the most important:

1.- Faul JL, Galindo J, Posadas-Valay R, Elizondo-Riojas G, Martinez A,

Cooper CB. An arteriovenous fistula increases exercise capacity in patients

with COPD. Chest. 2010;138:52–58

2.- C57. CARDIOPULMONARY INTERACTIONS IN THE INTENSIVE CARE UNIT : pp. A4634-A4634

Analysis Of Cardiovascular Adaptations Of COPD Patients To An Implanted Ateriovenous Fistula

First published online as doi:10.1164/ajrccm-conference.2012.185.1_MeetingAbstracts.A4634

3.- Bertog SC, Kolmer C, Kleschnew S, Franke J, Wunderlich N, Kardos P,

Sievert H. Percutaneous femoral arteriovenous shunt creation for advanced

chronic obstructive pulmonary disease: a single-center safety and efficacy

study. Circ Cardiovasc Interv. 2012;5:118 –126

The first 2 favors the procedure and the last one doesn¨t mainly giving alerts and concerns with respect to adverse events.

I´m not aware of any animal models that relates specifically to EPOC and AVF but there is much work on AVF and renal failure.

As I said before, not every advanced EPOC patient benefits of an AVF. It is important to know that the future AVF must have at least a 1 l/min flux to be useful and at the mean time the limb vascular state must be optimal for the procedure can develope a blood steel syndrome, therefore it is preferred to use a lower extremity. As important as that, knowing the right ventricular performance of the patient is critical because of the physiological changes on hemodynamics expected to take place.

Patricio, thank you for the references. The article by Bertog et al is very interesting, and there is a reply by Faul in the same journal. I am sure you have read both. I could not access the ATS articles.

I have been fascinated from my first lessons in Cardiovascular and Respiratory Physiology in medical school about how the body maintains homeostasis, especially when there are distortions from disease processes. The discussion section in Faul et al's article higlights the potential role of an increase in mixed venous oxygen.

Dr Faul and other mention in the letter/reply to Bertog's article that they have treated about 180 patients so far. It would be helpful to know if there are any long-term complications and what advantages (in terms of risk vs benefit) the procedure has over ambulatory oxygen, especially with the availability of oxygen canisters, portable oxygen concentrators etc.

Thanks again. References below.

Faul et al's study

Chest. 2010 Jul;138(1):52-8. doi: 10.1378/chest.09-2381. Epub 2010 Apr 9.

An arteriovenous fistula increases exercise capacity in patients with COPD.

Faul JL, Galindo J, Posadas-Valay R, Elizondo-Riojas G, Martinez A, Cooper CB

Bertog et al's original paper

Circ Cardiovasc Interv. 2012 Feb 1;5(1):118-26. doi: 10.1161/CIRCINTERVENTIONS.111.964494. Epub 2012 Feb 7.

Percutaneous femoral arteriovenous shunt creation for advanced chronic obstructive pulmonary disease: a single-center safety and efficacy study.

Bertog SC, Kolmer C, Kleschnew S, Franke J, Wunderlich N, Kardos P, Sievert H.

Faul's letter/reply to Bertog's article

Circ Cardiovasc Interv. 2012 Jun;5(3):e45; author reply e46. doi: 10.1161/CIRCINTERVENTIONS.112.969691.

Letter by Faul et al regarding article, "Percutaneous femoral arteriovenous shunt creation for advanced chronic obstructive pulmonary disease: a single-center safety and efficacy study".

Faul JL, Smyth RJ, Cormican LJ, Burke CM.