Transcatheter closure of patent foramen ovale with the SpiderTM PFOOccluder:Initial Clinical Experience

Department of Cardiology ,

Guangdong Cardiovascular Institute

Dr Yigao Huang, Dr Caojin Zhang

Patent foramen ovale (PFO) is quite common, with pr

evalence estimates from 10% to 35% of patients as deter

mined by ultrasound and autopsy studies, respectively.

The prevalence decreases gradually with increasing a

ge, from 34.3% during the first three decades to 20.2% d

uring the ninth decade.

1.Hagen PT, Scholz DG, Edwards WD. Mayo Clin Proc. 1984,59(1):17-20.

3. Fisher DC, Fisher EA, Budd JH,et al. Chest. 1995,107(6):1504-9.

2. Konstadt SN, Louie EK, Black S,et al. Anesthesiology. 1991,74(2):212-6.

4. Stendel R, Gramm HJ, Schröder K,et al. Anesthesiology. 2000 ,93(4):971-5.

Background

Prevalence of PFO is higher in patients with paradoxi

cal embolism and associated with increased risk for recu

rrent thromboembolic events.

The increased risk for recurrent thromboembolic even

ts can be avoided by percutaneous closure of PFO, surgi

cal closure or permanent oral anticoagulation .

1.Taaffe M, Fischer E, Baranowski A,et al. Am J Cardiol. 2008 ,101(9):1353-8.

Transcatheter closure of PFO is a promising alte

rnative to surgical closure or anticoagulation thera

py .

Currently,several devices are used for PFO closu

re, such as Amplatzer occluder , Helex occluder , a

nd CardioSEAL-STARflex occluder.

The aim of the present study was to evaluate t

he safety, feasibility and usefulness for closure of

PFO with a new PFO occluder - the SpiderTM

PFO Occluder(Lifetech Scientific (Shenzhen) C

o.Ltd,China.).

The SpiderTM PFO Occluder

Animal experiment

Material and methods

Guangxi BA-MA Mini-pigs were selected .

(provide by Guangxi University ,Animal technology college)

The fossa ovalis is punctured to establish the animal model of

PFO .

The SpiderTM PFO Occluder was chosen to occlude PFO und

er guidance of fluoroscopy.

After occlusion, mini-pigs were sacrifized at month 1, 2 ， 3

and 6 for gross inspection and microscopic inspection.

Puncture right femoro iliac vein after dissection

Position 8 F femoral arterial sheath

Perform pulmonary arterial angiography

Puncture atrial septum and position left atrial wire

Exchange to 10 F long sheath

Position occluder(16 mm)

The procedure of animal experiment

12 Guangxi BA-MA Mini-pigs were sele

cted to complete this experiment.

weight: 28.2 ±3.8 kg

procedure time ： 66.75±38.58 min

X-ray exposure time: 22.09±13.38 min

Results

The animal model of patent foramen ovale

The left atrium disc of the SpiderTM PFO Occluder after implantation

The right atrium disc of the SpiderTM PFO Occluder after implantation

The microscopic inspection at 1 month after occlusion

(micro× 100)

The microscopic inspection at 2 months after occlusion

(micro× 100)

The microscopic inspection at 3 months after occlusion (micro× 100)

The microscopic inspection at 6 months after occlusion

(micro× 200)

Results

No vegetation, thrombosis, broken strut, or erosion

was found on the surface of all devices.

The PFOs were completely occluded ,observed by T

TE from 1 to 6 months after occlusion.

The surface of the device was almost fully covered 1

month after occlusion. The left and right discs of the o

ccluder were primarily covered by accretionary collag

enous fibers and endothelial layers which are graduall

y thickening.

Clinical trialClinical trial

Patient Population

Between January 2006 and September 2008

25 patients with a PFO underwent percutaneous PFO closure.

The presence of a PFO was confirmed by transthoracic echoc

ardiography(TTE) and/or transesophageal echocardiography (T

EE) with a spontaneous or provocable (Valsalva manoeuvre) ri

ght-to-left shunt (RLS)

All patients gave written informed consent before the implant

ation procedure.

Degree of right-to-left shunt

Spontaneous or provoked right-to-left shunt was semi-quantitatively graded according to the amount of bubbles detected in the left atrium after crossing the interatrial septum on a still frame:

grade 0 = none,

grade 1 = minimal (1–5 bubbles),

grade 2 = moderate (6–20 bubbles),

grade 3 = severe (>20 bubbles) .The PFO size was additionally determined by multiplane two-dimensional TEE as recently reported by Schuchlenz et al.

Percutaneous PFO closureThe procedure was performed under local anaesthesia. The chosen PFO occluder was mounted on the delivery system and loaded into the transseptal sheath, with care taken to prevent air embolism. The occluder was advanced through the sheath into the left atrium until the left atrial part of the device was unfolded.After that, the whole unit was withdrawn under fluoroscopic and echocardiographic guidance against the interatrial septum. After it was determined that the device was in the correct position, the introducer sheath was further withdrawn, while constant tension was applied on the delivery cable until the right atrial part of the device unfolded. Optimal placement of the device was assured by TTE and the absence of a residual shunt after deployment by color flow Doppler and micro-bubble administration.

Set up the track

The procedure was performed under fluoroscopic guidance

The procedure was performed under echocardiographic guidance

The occluder is well positioned and shaped after the occlusion

Post interventional Treatment

All patients were treated with aspirin 100

mg once daily for 6 months, at which time

the medication was stopped unless required

for another indication.

Follow-Up Evaluation

A two-dimensional TTE, chest X-ray and routine-ECG was performed at 24 hours after transcatheter PFO closure . Patients were followed-up prospectively by TTE and/or TEE and clinically at 24 hours, 1 month, 3 months, 6 months, and 12 months after device implantation and yearly thereafter. Including extensive neurological (by a neurologist experienced in cerebrovascular diseases) and medical examination with a 12-lead ECG and a TTE and/or TEE at rest and during Valsalva-Maneuver. Follow-up events included death, recurrent neurological or peripheral thromboembolic events, and the need of reintervention for significant residual shunt or device malalignment.

Results

25 cases with PFO were diagnosed by TTE or TEE

male ： 10cases ； female ： 15cases;

mean age 35.1±13.8 years, range, 15 to 56 years

3 patients with brain embolism after more than 4 months

3 patients after thrombolytic therapy for a snake-like thrombus

on PFO

6 patients (2 male,4 female) with a repeated migraine history.

8 patients with platypnea-orthodeoxia syndrome

One patient with decompression sickness

4 cases without any symptoms (by physical examination)

22 patients had an ASD like closure (the catheter passe

d through the PFO directly)

3 patients needed an atrial septum puncture

All 25 cases procedure were successful.

Procedure time ( pass PFO) :37±45min

X-ray exposure time ： 17±34min

3 procedure time( AIS puncture) ： 153、 90 and 73min，respectively

X-ray exposure time: 121 、 40 and 26 min， respectively

TTE or TEE examination after operation 24 － 48 hours:

The position and shape of the occluders were good

Results

There were no deaths or no complications (i.e. air em

bolism or thromboembolism, bleeding, occluder dislod

gement, infection ,myocardial infarction or others) dur

ing the procedure.

Seven patients had frequent atrial premature beats o

r transient atrial tachycardia during implantation, whic

h terminated medically after implantation.

All patients have completed clinical follow-up at least 6 months(25±11,6-39 months).

No complications

No migraine

Blood examination:

Homocytology shows no abnormality

Renal function shows no abnormality

Liver function is normal

Follow-up

The SpiderTM PFO occluder is the first device made in China.

The SpiderTM PFO occluder have some special characters :

1. Conventional Right Atrial Disc.

2. Left Atrial Disc is a ePTFE membrane with four or six

braided ceramic deposit anchors, which may minimize

risk of thrombus formation.

3.An active link between the Left Atrial Disc and the

Right Atrial Disc allows the Left Atrail Disc to conform

to the anatomy of atrial septum.

Discussion

1.Taaffe M, Fischer E, Baranowski A, et al. Am J Cardiol. 2008,101(9):1353-1358.2.Spies C, Khandelwal A, Timmemanns I,et al. Catheter Cardiovasc Interv. 2008 ,72(7):966-70.

3.Luermans JG, Post MC, Plokker HW,et al. Neth Heart J. 2008 ,16(10):332-6.

The summary conclusion of the present study is tha

t the interventional PFO closure

ｗ ith the SpiderTM PFO occluder is a safe and effecti

ve technique with a high success rate.

Our data is in good agreement with previous studie

s using different transcatheter occluder systems.

SpiderTM PFO occluder is a good choice for a transcath

eter PFO closure

If the catheter passes directly through PFO to create th

e path, a relative small size device can be selected.

If it is difficult for catheter passing the PFO (over 20

minutes) , the method of puncturing the atrial septum s

hould be used, and a relative larger size device will be

selected.

Firstly, our patient population was a selecte

d cohort referred to our institution for percuta

neous PFO closure and might differ from othe

r series published.

Secondly, the number of our patient populat

ion was smaller than other studies’.

Limitations of our study

Conclusion

Transcatheter closure of PFO with the SpiderT

M PFO Occluder is a safe and effective therapeuti

c option .

To further evaluate this strategy, randomized tr

ials comparing this device with other devices an

d therapies have to be performed

Guangdong General hospital