Role of Interventional Catheterization in Post-Operative

TOF Patients

Jennifer Rutledge, MDOctober 25, 2013

What is our role?

• To keep patients with TOF away from the surgeons as long as possible

What is our role?

• Treat / palliate the residual lesions patients may be left with and delay the need for future cardiac surgery

• Hopefully to improve outcome and quality of life

Outline

• When, Why and How?– Timing of intervention

• Immediate post-operative versus later– Palliative procedures versus complete repair

• Shunts• Pulmonary arteries• Conduits and Valves

Timing of Intervention: Early Post-Op

• Patients who have difficulty recovering after surgery have a higher incidence of residual lesions

• Diagnostic cath can be performed safely in the early post-op period and often results in the discovery of lesions that require further intervention

Timing of Intervention: Early Post-Op

• Interventional cath has historically been avoided in the immediate post-op period

• Concerns:– Transport of critically ill patients– Worsening clinical status as a result of the

procedure– Fear of disruption (rupture) of fresh suture line

Timing of Intervention: Early Post-Op

• Commonly thought a minimum of 6 weeks of adequate scar tissue formation is required for safe intervention

• Recent data suggests intervention can be performed safely < 6 weeks

• Performance of successful catheter intervention can improve survival to discharge

Timing of Intervention: Early Post-Op

• Intervention only considered if the lesion is severe enough to compromise clinical status and repeat surgery is considered to be high risk

• Requires multidisciplinary team• Interventional cath doc• Surgeon• Intensivist• Anesthesiologist• Nurses, RT, anesthesia and radiology technicians• ECMO team• Operating room team including nursing and perfusion

Timing of Intervention

• Timing of catheterization outside of the immediate post-op period is largely based on non-invasive imaging and standard criteria– Significant right ventricular outflow tract

obstruction– Branch pulmonary artery stenosis – Severe pulmonary valve regurgitation

Types of Intervention: Neonatal Shunts

• Rarely performed in this population– Anomalous coronary artery– Multiple large VSD’s or TOF/AVSD– Contraindication to bypass

• Central versus modified Blalock-Taussig shunt

Shunts

• Shunt obstruction can occur 3-20% of cases– Thrombosis, suture line stenosis, intimal

proliferation, vascular distortion, ductal tissue constriction

– Results in cyanosis of the patient – can be life-threatening

– Most often occurs acutely after surgery but can occur late

– Risk factors: small shunt and pulmonary artery size, polycythemia, competitive blood flow

Shunts

• Interventional cath options:– Mechanical or pharmacological disruption of clot

• Goal is to break up the clot and dislodge it distally, improving flow across the shunt

• Can be achieved manually by using catheters/wires/balloons but only useful for fresh clot

• May be achieved by local thrombolysis or thrombectomy

– Local injection of TPA – often requires prolonged infusions» Not practical for shunts or fresh post-op patients

Shunts

• Shunt thrombosis most often develops in association with a stenosis of the shunt and/or adjacent blood vessel– Balloon dilation or stenting performed to disrupt

the clot and treat the stenotic lesion– In the immediate post-op period stenting likely

safer • More predictable and durable result, less recoil of

vessel, smaller balloon/stenosis ratio for effective expansion

Shunts

Shunts

Shunts

Pulmonary Arteries

• Branch pulmonary artery stenosis is a well-known association in TOF population– Post-surgical: at suture line (shunts, proximal

branches), ductal constriction– Native: proximal or distal branches

• Balloon dilation or stenting– What type of intervention is determined by

patient/vessel size and anatomy, timing of surgical intervention (past, present and future)

Pulmonary Arteries

• Lots of toys– Regular balloons– High pressure balloons– Ultra-high pressure balloons– Cutting balloons

Pulmonary Arteries

• Intravascular Stents:– Ideally we like to implant stents that can be

further dilated to adult size– Depending on the patient size, this is not always

possible• Place smaller stents that will then need to be cut across

at the time of subsequent surgery

Pulmonary Arteries

Bergersen L et al. Cardiol Young 2005;15:597-604

Pulmonary Arteries

Bergersen L et al. Cardiol Young 2005;15:597-604

Pulmonary Arteries

Pulmonary Arteries

Pulmonary Arteries

Angtuaco, M. et al. Cathet Cardiovasc Int. 2011;77:395-399.

Pulmonary Artery Growth

Conduits

• Frequently used in patients with TOF at various stages of life

• Conduits fail due to stenosis and/or regurgitation

• Freedom from conduit replacement 68-95% at 5 years and 0-59% at 10 years

• Surgical conduit revision may be delayed in some patients by cath intervention

Conduits

• Balloon dilation alone rarely achieves good result

• Contraindication to conduit stenting– Anomalous coronary

artery positioned behind the conduit

• Risk of coronary compression

Conduits

Peng LF et al. Circulation 2006;113:2598-2605.

Freedom from conduit surgery

Conduits

• Risk factors for need for earlier re-intervention– Younger age, higher pre-stent RV pressure,

diagnosis OTHER than TOF, homograft conduits, conduits ≤ 10 mm

• Stent fracture seen in 43%– 89% immediately behind the sternum– 82% had compromise of the integrity of the stent

Peng LF et al. Circulation 2006;113:2598-2605.

Conduits

Chronic Pulmonary Regurgitation

• Any patient with transannular patch repair• Majority of patients following conduit or

bioprosthetic valve implantation• Ultimately all patients with TOF will require

therapy (repeated) for chronic PR

Transcatheter Valves

• Developed to treat dysfunctional bioprosthetic valves or conduits and reduce number of and prolong time to next surgical intervention

• Two current options– Medtronic Melody valve– Edwards Sapien valve

Melody Valve

• Bovine jugular vein; platinum/iridium stent

• Available in Canada since late 2005; as of May 2013 there have been over 5000 implants in 180 centers in 35 countries– ~50% have underlying diagnosis of TOF

Melody Valve

• Can be considered in patients:– > 30 kg, vessels large enough to accommodate the

22F sheath– Implant site 16-22 (24) mm in diameter – Evidence of conduit/valve dysfunction

Melody Valve

www.medtronic.com

Patie

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Regurgitation Stenosis Mixed

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Melody Valve

Courtesy Medtronic

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Baseline Patient CharacteristicsConduit Type

US IDEUKGermanItalianCanadian

Melody Valve

Courtesy Medtronic

Long-term OutcomesPulmonary Valve Competence by Echocardiography

0%

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3 years

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Long Term Pulmonary Valve Competence

Courtesy Medtronic

Courtesy Medtronic

Melody Valve

• Freedom from re-operation:– Canada: 91%, 83% and 83% at 12, 24 and 36

months, respectively• Freedom from transcatheter intervention

– Canada: 91% 1 year, 80% 2 year

Courtesy Medtronic

ComplicationsStent Fractures (%)Pa

tient

s, %

24 28 12 30 7.5Follow up (months)

Melody Valve: Complications

• Stent fracture in 5-25%– Increased use of pre-stenting of conduits reduces

this risk• Conduit rupture - ~4% requiring treatment

(covered stent/surgery)– <1% “uncontained” rupture but can be fatal

• Coronary artery compression– Can be seen in ~5% of patients during test evaluation– Can be catastrophic

Morray BH et al. Circ Cardio Int;2013:6:535-542

Transcatheter Valve

• Melody valve was expanded the role of interventional cath in post-operative patients

• Limited size range• There are many patients with conduits and

valves that are not candidates for a Melody valve

Sapien Valve

• Bovine pericardial valve leaflets hand-sewn into a slotted stainless steel stent

• Fabric sealing cuff on lower portion of stent• Designed for aortic position• Can be considered for pulmonary valves/conduits

~21 - 30 mm in diameter, patients > 30-35 kg• Shorter stent requires that conduits are fully

stented prior to Sapien valve insertion

Edwards Lifesciences

Sapien Valve

Sapien vs. Melody

Faza et al. Cathet Cardiovasc Int 2013;82(4):E535-41.

Sapien vs. Melody

Faza et al. Cathet Cardiovasc Int 2013;82(4):E535-41.

Transannular Patch

• What about the really large RVOT’s?• Medtronic Native Outflow Tract Pulmonary

Valve

Courtesy Medtronic

Medtronic’s Early Feasibility Study: Non-randomized, Prospective

• Primary Objective:– Obtain in vivo data to confirm assumptions on loading conditions for

future in vitro frame evaluations• Secondary Objectives:

– Characterize procedural feasibility, safety & TPV performance• Up to 20 subjects - Consented for 5 year follow-up at 3 North

American Centers (Implants spring 2014 – F/U to 2019)– The Hospital for Sick Children ,Toronto Canada – Dr. Lee Benson– Nationwide Children’s Hospital, Columbus Ohio – Dr. John Cheatham– Children’s Hospital, Boston MA – Dr. Jim Lock

Courtesy Medtronic

Courtesy Medtronic

Conclusion

• Patients with TOF are left with residual lesions• Cardiac cath lab procedures can treat or

palliate many of these lesions and delay the need for repeat cardiac surgery

• Future advances will expand the therapeutic options to include a broader range of patient diagnoses and patient sizes