PERCUTANEOUS INTERVENTIONS IN OBSTRUCTIVE CHD

Dr.Tahsin.NJan 2012

Overview

1. Endovascular Stents

2. Balloon Aortic Valvuloplasty

3. Balloon Pulmonary Valvuloplasty

4. Perforation of the Atretic Pulmonary Valve

5. Mitral Valve Dilation

6. Tricuspid Valve Dilation

7. Coarctation, Recoarctation and Aortic Arch

Obstructions

8. Branch Pulmonary Artery Stenoses

9. Pulmonary Vein Stenoses

10. Systemic Vein Stenoses

Endovascular Stents

Low profile that allows introduction through small delivery

sheaths

Easy crimp ability or availability as premounted stents

Possibility for re-expansion to adult size

High degree of flexibility for placement around curved

structures

Allowance for rehabilitation of vessels that are overlapped

by the placed stent through the stent meshwork/cells

(e.g., open-cell design)

High radial force to accommodate very tight and scarred

lesions

Rounded atraumatic edges that avoid damage to the

vessel and the balloon

Nonexisting or low degree of stent-shortening during

expansion

Stent material - MRI compliant, noncorrosive, and

does not lead to increased blood levels of metal

Low risk of neointimal proliferation, possibly through

internal coating

Possibility of biodegradable material with a platform

to sustain drug coating to minimize tissue reaction

Balloon Aortic Valvuloplasty

Indications

Peak-to-peak gradient >60 mm Hg

Asymptomatic patients

Peak-to-peak gradient > 50 mm Hg

Symptomatic patient or

ECG changes - ischemic

AS in the critically ill neonate

Dilated left ventricle and poor left ventricular

function

Retrograde - Less traumatic

Antegrade - Better balloon position, No arterial injury

Single balloon - Antegrade

Double balloon - More dilation older patients

Cross aortic valve ; most difficult step

JR / JL /Multipurpose Catheter

Balloon across valve;

Rapid inflation & deflation

Longer balloons

Adenosine – Cardiac standstill

Rapid RV pacing

Balloon size

Single-balloon technique - 80% of the measured aortic

annulus diameter

Double-balloon technique - combined diameters 1.2

times the measured diameter of the aortic annulus

Complications

Femoral artery complications –

Avoided by

Antegrade approach

Carotid approach

Double balloon

Aortic regurgitation with AVR

Outcome

Gradient by 60% to 70% or to a gradient of 30 to 40

mm of Hg

Long-term results surgical valvotomy – palliative

without a sternotomy or cardiopulmonary bypass

In pediatric patients and young adults is now the

standard initial procedure in most centers

Balloon Pulmonary Valvuloplasty

First introduced by Kan et al. in 1982

December 1986 - 28 centers - reporting to VACA

- successful and safe technique in >680 cases

Standard therapeutic procedure for pulmonary valvar

stenosis in all ages from the newborn period throughout

adult life

Maximum instantaneous systolic echo gradients of 35

mm Hg with evidence of right ventricular hypertrophy

Long exchange wire to LPA or Duct – Desc. aorta

Optimum balloon diameter - between 1.2 and 1.3 times the

size of the pulmonary valve annulus for a single-balloon

dilation

Low pressure balloons Tyshak II (NuMED, Hopkinton, NY)

with a lower profile

Smaller size

High-pressure balloons ZMed II (NuMED, Hopkinton, NY)

or the double-balloon technique

Larger size – older pts

Dysplastic, thickened pulmonary valves

Associated supravalvar narrowing

Smaller coronary balloons can facilitate predilating the

valve

Gradient across the nondysplastic pulmonary valve to <10 mm

Hg Reduction in the RV-to-systemic pressure ratio

Relief of the valvar stenosis may unmask infundibular obstruction

Infundibular obstruction - dynamic - regress with time

Dysplastic valves

higher-pressure

gradient reduction less

Immediate results

Good immediate results >95% pts

Very Low mortality rates

Improved Rv fn

Decrease in TR

Complications

Arrhythmia

Hypotension / collapse

Blood loss

RV / Tricuspid valve injury

Pulm valve / annulus disruption

VACA registry

Death 0.24%

Major complications 0.35%

Long term results

Restenosis - 5% to 11% within 10 years

Risk factors

Infancy

Very dysplastic pulmonary valves

Undersized balloon

No evidence of increased PV replacement

Perforation of the Atretic Pulmonary Valve

Pulmonary atresia with intact ventricular septum

(PA/IVS)

Palliative

Acutely decompresses the right ventricle

Facilitate growth of an initially hypoplastic right

ventricle

Suitability by 2D echocardiography

Minimal criteria

Tripartite right ventricle

Membranous atretic pulmonary valve

Well formed infundibulum

Measure right ventricular and systemic arterial pressures

RV angiography with 20-degree cranial angulation & lateral

projection Measure pulmonary valve plate diameter

Exclude of RV-dependent coronary circulation

LV angiography - same projection – Assess Valve plate

Nykanen RF perforation wire and the Baylis radiofrequency

puncture generator

Power setting of 5 W/s

Balloon dilation performed

Low-profile balloon valvuloplasty catheter- Mini-

Tyshak

Diameter of about 130% of the valve plate annulus

Ductal stenting / surgical shunt – 50%

Outcome

Most series are very small - include fewer than five

patients

Overall procedural mortality - 8%

Incidence of procedural complications -15%

75% - biventricular or one-and-a-half ventricle

circulation

Mitral Valve Dilation

Anatomy of congenital MS

Variable

Less favorable for balloon dilation than rheumatic

Femoral veins - transseptal approach – LA - LV

Single or double balloon

Inoue

Two balloon diameters = the measured or estimated maximal normal mitral valve diameter for the patient

Transseptal Puncture

Transseptal needleBrockenbrough needle with a transseptal Mullins introducer set (Cook)

Radiofrequency energy

Minimal force and a much lower risk of injuring adjacent

structures

Toronto transseptal catheter with the 8 Fr TorFlex

transseptal sheath and dilator

Curved at the end by about 210 degrees - avoid

continued perforation of adjacent structures

Increased stiffness

Larger patients

In small infants

4 or 5 French Judkins right (JR) catheter

A 180-cm 0.035-inch outer diameter coaxial injectable

catheter (Baylis) is loaded over a 260-cm 0.024-inch

Nykanen RF perforation wire

McElhinney et al. 108 patients with congenital MS

Median age - 18 months

BMV - reduction of the mean gradient by - 38%

Significant MR - 28%

Overall 5-year survival - 69%

Later stages of the institutional experience - 87%

The early mortality BMV = surgical mitral valvuloplasty

Initial procedure - typical congenital MS or double-orifice

mitral valve

Surgical approach - supra valve mitral ring and

parachute mitral valve

Parachute MV

Not a contraindication to BMV

Less effective - single papillary muscle or severe

shortening or virtual absence of the chordal apparatus

Tricuspid Valve Dilation

Congenital TS

Associated with other cardiac lesions

Less amenable to balloon valvuloplasty than rheumatic

Similar to BMV

Balloon size equal to estimated TV diameter

A successful dilation should eliminate any transvalvar gradient

Limited experience

Coarctation, Recoarctation and Aortic Arch Obstructions

1979 Sos et al. native coarctation in postmortem specimens

1980 Dr. James Lock et al excised human coarctations as well as experimentally induced coarctations in lambs

Dr. Ronald Grifka and Dr. Charles E. Mullins et al., - Texas Children's Hospital - endovascular stent therapy to treat coarctation

1995, Suarez de Lezo reported the first large series of stent implantation to treat native and recurrent coarctation in humans using the Palmaz stent

1999 Cheatham first reported on a new stent design, the Cheatham-Platinum (CP) stent - also available in a PTFe-covered variety

Cylindrical fixed maximal-diameter dilating balloons-

high pressures

Goal of the procedure –

Reduction in the gradient to <10 mm Hg or

90% relief of the obstruction angiographically

Zabal et al. - cohort of 54 pts - observational study

Residual gradient of >10 mm Hg was associated with

a significantly higher failure index (heart-related

death, a gradient on follow-up of >20 mm Hg, and

the need for reintervention or complications such as

aneurysm formation)

Balloon Dilation in CoA

Stents in CoA

Bare or Covered Stent

In smaller patients with an

expected diameter below average

adult size, the Genesis XD or the

Mega LD stents with a maximum

expandable diameter of 18 mm.

If larger maximum diameters are

required, the Max LD, the

Cheatham-Platinum, or older

Palmaz XL (Cordis, Warren, NJ)

stents with maximum expandable

diameters >25 mm

Cheatham-Platinum covered stent

Balloon angioplasty alone for native coarctation in smaller children and infants - 66% recoarctation rate.

Interventions for native coarctation - greater incidence of aortic aneurysm formation

Catastrophic events as a direct result of aneurysms are rare

Dilation of native coarctation more reasonable for discrete lesions in patients >7 to 12 months of age

In the larger child, primary stent therapy for native coarctation - gradual conservative expansion of stents over two or three procedures to reduce the incidence of dissection or aneurysm formation

Branch Pulmonary Artery StenosesAccepted standard procedure - not amenable to surgical repair

Reduction in the RV -to-systemic pressure ratio - good indicator for a successful outcome.

Individual pressure gradients to branch pulmonary arteries may be less meaningful

IJV or transhepatic approaches eliminates some of the double-S curves that have to be traversed from a femoral venous approach – better pushability

Balloon should preferably between 2 to 3 times the stenotic area

High pressure balloons & Cutting balloons may be required

Intravascular stents have become the primary mode of therapy for branch pulmonary artery stenoses (except infants)

Pulmonary Vein Stenoses

Surgical & transcatheter interventions for pulmonary vein stenoses - uniformly bad long-term outcome

Performed as a last resort before considering heart - lung transplantation

Restenosis is observed in most cases

Stents –

No better medium- or long-term results than (cutting) balloon angioplasty alone

Short-term results may be superior than angioplasty

High percentage of complications - systemic stent embolization

Systemic Vein Stenoses

Successful and carries little risk - even in freshly operated lesions

Surgical alternative for these lesions is poor to nonexistent

Stenosis recurs in most cases

The balloon size between 2 & 3 times the diameter of the stenosed segment

Primary therapy for long-standing venous lesions - intravascular stents

RF energy with covered stents may allow the recanalization of even completely obstructed venous structures

Results of central venous stent implantations - excellent.

No adverse reactions or long-term complications of the stents

Venous restenoses when stents were overdilated

Conclusion

Treatment of choice in many conditions

Evidence to prove superiority over Sx is lacking

No randomised Trials, only institutional series

More dedicated hardwares are required

Number of centres offering expert Rx increased recently

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