12 g butera metodiche interventistiche

Metodiche interventistiche nelle patologie cardiache congenite

Gianfranco Butera Policlinico San Donato IRCCS

What is fetal interven.on?

•  Fetal interven7on is reaching inside the uterus to help a fetus who has a problem.

•  All fetal interven7on is really maternal-‐fetal interven7on

Focus is on defects which can be accurately identified antenatally and

which cause progressive and permanent damage to the fetus if

not corrected.

Michael Tynan and Lindsey Allan

256

Balloon dilatation of the aortic valve in the fetus:

a report of two cases

Darryl Maxwell, Lindsey Allan, Michael J Tynan

AbstractBecause they had irreversible damage to

the left ventricular myocardium none of

12 patients with critical aortic stenosis

diagnosed prenatally survived after

postnatal treatment. This experience

prompted three attempts at intrauterine

balloon dilatation of the aortic valve in

two fetuses with this condition. On each

attempt the balloon catheter was

successfully delivered to the left ventri-

cle. In the first fetus the aortic valve was

not crossed and the fetus died the next

day. In the second fetus the balloon was

correctly positioned across the aortic

valve and inflated in the valve ring. After

delivery, a further balloon angioplasty

was performed; this relieved the stenosis

but the patient died five weeks later from

persisting left ventricular dysfunction

related to endocardial fibroelastosis.

Balloon angioplasty is feasible in fetal

life but the prognosis depends on the

ability of the relief of stenosis to limit,

prevent, or allow regression of left

ventricular damage before delivery.

Department ofFetal Medicine,Guy's Hospital,LondonD MaxwellDepartment ofPerinatal Cardiology,Guy's Hospital,LondonL AllanDepartment ofPaediatric Cardiology,Guy's Hospital,LondonM J TynanCorrespondence to

Dr Lindsey Allan,Department of Perinatal

Cardiology, 15th Floor,Guy's Hospital, St Thomas's

Street, London SEI 9RT.

Accepted for publication22 January 1991

The mildest forms of congenital aortic

stenosis may become haemodynamically

important only in late adult life when calcifica-

tion becomes a prominent feature whereas the

most severe forms are life threatening in

infancy. In the neonate mortality is high and

left ventricular dysfunction with endocardial

fibroelastosis is common. Even when the

obstruction to the left ventricular outflow tract

is relieved the left ventricle often fails to

maintain cardiac output.

Recently, it has become possible to detect

both aortic stenosis and the severer forms of

endocardial fibroelastosis in fetal life. In our

unit, 28 fetuses were identified as having aortic

stenosis alone (two cases) or aortic stenosis

with endocardial fibroelastosis (26 cases). In

two of the 12 mothers who elected to continue

the pregnancy there was an intrauterine death.

None of the 10 livebirths survived; only four

survived long enough for treatment by balloon

dilatation of the aortic valve. In addition, we

saw another prenatal feature that influenced

the outcome. In four of the 28 fetuses, the left

ventricle failed to grow normally as gestation

advanced and the left ventricle became hypo-

plastic which made the neonate unsuitable for

relief of aortic valve obstruction.'

Balloon dilatation is a well established

technique for the relief of pulmonary or aortic

Br Heart J 1991;65:256-8

stenosis in children.23 Its efficacy in the new-

born is being compared with that of surgical

valvotomy.4 We attempted balloon dilatation

in the fetus in an attempt to improve the

dismal prognosis for this condition by

relieving obstruction to the aortic valve before

irreversible left ventricular damage had

developed and to try to prevent the growth

failure that we had seen. We report our

experience in two fetuses in whom balloon

dilatation of the aortic valve was attempted.

Patients and methodsBoth patients were referred to the Department

of Perinatal Cardiology after a four chamber

view of the heart in the local hospital indicated

an abnormality. They were examined by an

Advanced Technical Laboratories Mark 4

sector scanner and a Hewlett Packard 77020A

phased array scanner with 5 MHz transducers.

Both machines can be used for Doppler

evaluation of intracardiac velocities and the

Hewlett Packard 77020A can be used for colour

flow mapping.The parents were extensively counselled

about the experimental nature of the

procedures to be attempted. The therapeutic

procedures were performed in the Fetal

Medicine Unit at Guy's Hospital with an

Acuson 128 ultrasound system for visualisation

of the needle course and manipulation of the

guide wires and balloon catheters. Eighteen

gauge transabdominal chorionic villus sam-

pling needles were used (Rockett, London).

For needle puncture of the umbilical cord and

cardiac chambers we used a freehand ultra-

sound guided method adapted from the tech-

nique first described by Daffos et al.' The

maternal skin was infiltrated by local anaes-

thetic before each needle insertion. Intra-

uterine and intracardiac pressures were

measured by a sterile system of fluid-filled

tubing connected from the hub ofthe needle via

a solid state transducer to a Siemans Mingograf

by a previously described method.6 In the first

procedure we used a USCI coronary balloon

catheter, diameter 2-5 mmwhen inflated. In the

second case a 3-5 mm diameter balloon was

custom made by NuMed.

CASE 1This 23 year old woman (para 2) was initially

referred at 22 weeks' gestation. The left

ventricle was of normal size for the gestation

but was contracting poorly. There was little

discernible forward flow into the left ventricle

or aorta. The left ventricular wall showed

• 12 fetuses, 27-33 weeks, 8 isolated AS, 2 AA, 2 PS+AS • 7/8 Pts with isolated AS – technically successful • 4 died within 24 hours of fetal intervention • 6 died after postnatal therapy • 2 survivors

• One had procedure at 33 weeks (dilated LV - would not have developed HLHS?)

• One survivor – procedure was technically unsuccessful

Aim of Fetal Cardiac Interven.ons

1)  Promote ventricular growth and func7on •  Univentricular Biventricular circula7on

•  Aor7c stenosis with evolving HLHS •  Pulmonary stenosis or atresia and evolving HRHS

2)  Improve survival •  HLHS with intact atrial septum •  Salvage procedures (e.g. hydrops)

•  Fetal pacing for complete heart block?

The most common fetal cardiac interven7on procedure is AORTIC VALVULOPLASTY

The primary indica7on for fetal aor7c valvuloplasty is to alter the in utero natural

history of midgesta7on fetal aor7c stenosis with evolving HLHS

HLHS

Selec.on Guidelines for Fetal Aor.c Valvuloplasty

3 POINTS

1.  The dominant cardiac anatomic anomaly is valvar aor7c stenosis

2.  Evolving HLHS 3.  There is poten7al for a technically successful

procedure and biventricular outcome postnatally.

1.   The dominant cardiac anatomic anomaly is valvar aor.c stenosis

with ALL of the following: – Decreased mobility of valve leaflets – Antegrade Doppler color flow jet across aor7c valve smaller than the valve annulus diameter

– No or minimal subvalvar LV ouWlow obstruc7on


2. Evolving HLHS

–  LV func7on qualita7vely depressed AND

–  EITHER retrograde or bidirec7onal flow in the transverse aor7c arch (between the first 2 brachiocephalic vessels) at any 7me during the cardiac cycle

– OR two of the following: •  Monophasic MV inflow (Doppler profile of MV inflow without discrete E and A waves),

•  Le\-‐to-‐right flow across atrial septum or intact atrial septum (bulging le\ to right),

•  Bidirec7onal flow in pulmonary veins


3. There is poten.al for a technically successful procedure and biventricular outcome postnatally

1 point for each of the following: •  LV long axis Z-‐score > 0 •  LV short axis Z-‐score > 0 •  Aor7c anulus Z-‐score > -‐3.5 •  Mitral valve anulus Z-‐score > -‐2 •  Mitral valve or aor7c stenosis maximum gradient ≥ 20 mmHg

A score ≥4 had 100% sensi7vity, 53% specificity, 38% posi7ve predic7ve value, and 100% nega7ve predic7ve value.


Fetal angioplasty

•  Maternal conscious seda7on and regional spinal blockade conducted by an anesthesiologist.

•  An appropriate fetal lie is achieved by external version. •  Maternal posi7oning is kept with le\ uterine displacement. •  To promote uterine relaxa7on mothers are given nifedipine

20 mg TID for 48-‐72 hours, star7ng 12-‐24 hours before the procedure.

•  If ideal fetal posi7oning cannot be agained by external manipula7on, the procedure should be abandoned.

•  A\er op7mal fetal posi7on is achieved, the fetus is anesthe7zed using a mixture of fentanil (5-‐10 micrograms/kg), pancuronium (10-‐20 micrograms/Kg) and atropine (20 micrograms/kg) given intramuscularly or in the umbilical chord using a 21-‐22G Chiba needle.

•  Cardiac access is agained through direct needle puncture of the fetal heart via the uterus and the fetal chest wall.

•  Under con7nuous two-‐dimensional ultrasound guidance a 15-‐cm-‐long 17-‐to-‐18-‐gauge Chiba needle (with a stylet) is advanced to the target

•  The imaging plane is carefully adjusted to yield a picture in which both the en7re needle length and the target cardiac chamber are included in the field of view

Fetal angioplasty

•  The Ventricle is entered at the apex, with the needle course parallel to the ouWlow track directed at the steno7c/atre7c semilunar valves.

•  In this way the valves can be crossed almost blindly, with minimal wire and catheter manipula7on.

•  A\er stylet removal, the catheter system is introduced and advanced un7l the sha\ mark reaches the proximal hub of the needle.

•  Balloon posi7oning for infla7on is based on the external aforemen7oned measurements and ultrasound imaging, with emphasis given to the visualiza7on of the guide wire

Fetal angioplasty

•  Balloons are inflated with pressure gauges to allow precise es7mates of infla7on diameters.

•  Balloon diameters 10-‐30% larger than the aor7c or pulmonary valve annulus are selected for valve dila7on.

•  Two to four infla7ons are performed depending on the fetal clinical status.

•  A\er dilata7on, the whole system (needle + balloon + wire) is withdrawn as a unit through the fetal cardiac wall and out of the fetal and maternal bodies to avoid shearing off the balloon from the catheter sha\.

Fetal angioplasty

•  A pre-‐marked system (a rapid exchange 10 mm long coronary balloon pre mounted over a cut-‐off 0.014” floppy 7p guide wire) is advanced to the desired loca7on.

•  The needle, guide wire, and balloon sha\s are premeasured and marked so that posi7oning within the fetal heart is known from external measurements rather than the ultrasound imaging alone.

•  The balloon sha\ is marked with sterile tapes so that no more than the full length of the balloon is extruded out of the Chiba needle 7p when fully advanced.

•  The wire is also fixed with sterile tapes so that no more than 3-‐4 cm of the distal flexible wire straight 7p extruded out from the balloon 7p.

Fetal angioplasty

Fetal angioplasty

Fetal Interven7on for AS Aor7c Regurgita7on

•  Agempted procedures n=92 •  Technically successful 71/92 (77%) •  Aor7c regurgita7on

– None 1/3, mild 1/3, mod-‐severe 1/3 •  Fetuses with mod-‐severe were younger •  Larger BAR associated with more severe AR (>1.2) •  AR had no associa7on with fetal demise •  85% were born with none or mild AR

•  48% Technically successful and live born have achieved a biventricular repair

1.  Bradycardia (40%) – treatable 2.  Hemopericardium requiring drainage 3.  Balloon rupture – resolves 4.  Moderate-‐severe AR (40%) – resolves 5.  Peri-‐procedural fetal demise (10%)

Complications

Mizrahi-Arnaud A - Pediatric Research 2007

Fetal Aor.c Regurgita.on

Antegrade flow Aor7c regurgita7on

Results 2 Ventricle 1 Ventricle Unsuccessful

Mean±SD Z scores of the aor.c annulus (A), MV annulus (B), LV short axis (C), and LV long axis (D) at the .me of prenatal interven.on and at the latest follow-‐up fetal echocardiogram aXer technically

successful interven.on and comparison fetuses (control).

McElhinney D B et al. Circulation. 2009;120:1482-1490

Summary In utero balloon aor.c valvuloplasty

•  AR occurred in 63% of our fetuses after BAV (44/69 technically successful)

•  AR resolved completely in 73% who had AR (28/38 live-born)

•  AR grade improved among the remaining 7/10 patients who had any residual AR at birth

•  2 patients had moderate or severe AR at birth and one had mild AR

Fetal AR

1.  Why does fetal AR appear to be well tolerated? 1.  Low systemic resistance – placenta

2.  High LVEDP in fetus with AS – mi7gates the degree of AR

3.  RV is providing circulatory support

2.  Why does AR improve post-‐BAV? 1.  Unique hemodynamics result in less mechanical stress

on the valve

2.  Fetal valves are dynamic, contain prolifera7ng cells with an immature phenotype

3.  Underlying pathologic stenosing process

Personal experience

•  2 cases

•  24 Weeks GA

•  Detec7on at 22 WGA

•  Pa7ents should have a prenatal echocardiographic diagnosis of PA/IVS or cri7cal pulmonary stenosis with the following features:

•  membranous pulmonary atresia, with iden7fiable pulmonary valve (PV) leaflets or membrane,

•  no or minimal systolic opening, •  and no or minimal color Doppler ultrasound flow across the pulmonary valve (PV);

•  an intact ventricular septum; •  le\-‐to-‐right shun7ng across a patent ductus arteriosus (PDA);

Pulmonary atresia/IVS and evolving hypoplas.c right heart syndrome

•  Pa7ents should have a prenatal echocardiographic diagnosis of PA/IVS with the following features:

•  right heart hypoplasia, with a tricuspid valve (TV) annulus Z score below < 2 and an iden7fiable but qualita7vely small right ventricle (RV)

•  with no evidence of RV growth a\er 2-‐4 weeks of serial echocardiographic evalua7on.

•  Cases with fetal diagnosis of major coronary-‐to-‐RV fistulas should be excluded. Pulmonary valvuloplasty is performed between 24 and 30 weeks’ gesta7on.

Pulmonary atresia/IVS and evolving hypoplas.c right heart syndrome

Pulmonary atresia/IVS

Tricuspid Valve Z-‐score > -‐3 at mid-‐ and late fetal echo is an indicator of biventricular repair

Pulmonary atresia/IVS

1.  Bradycardia (40%) – treatable

2.  Hemopericardium requiring drainage

3.  Balloon rupture – resolves

4.  Moderate-‐severe PR – resolves

5.  Peri-‐procedural fetal demise (10%)

Tworetzky W, McElhinney DB, Marz GR, Benson CB, Brusseau R, Morash D, Wilkins-‐Haug LE,Lock JE, Marshall AC. In utero valvuloplasty for pulmonary atresia with hypoplasMc right ventricle: techniques and outcomes. Pediatrics. 2009 Sep 124(3):e510-‐8.

10 cases reported (GA 21-‐28 weeks). Success 60%. Fetuses who underwent successful interven7ons were older (range: 23–28 weeks; median: 26 weeks).

The procedure on the right ventricle is more challenging

due to: the more complex RV geometry, the smaller size of

the right ventricle compared to the le\, and the fact that

RVOT is behind the sternum.

Atrial septostomy in HLHS

Atrial septostomy in HLHS

Limita.ons/Failures of Fetal Interven.ons

1)  Technical limita7ons •  Fetal posi7oning •  Fetal stabiliza7on / movement

•  Imaging •  Equipment inadequacies

2)  Biological limita7ons

•  No animal model •  Late referral

•  Pa7ent selec7on •  No uniform postnatal approach

Thank you for your agen7on

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12 g butera metodiche interventistiche