BALLOON AORTIC VALVULOPLASTY

Dr.N.PraveenFinal Yr PG

IntroductionAortic stenosis (AS) is the most common form of adult valvular heart

disease, more prevalent in the aging population.Surgical Aortic Valve Replacement (SAVR) is the treatment of choice,

only definitive treatment to relieve symptoms or to improve survival.Despite extensive/exhaustive guidelines and recommendations one

third of patients are not referred to surgery – because of old age, left ventricular dysfunction and comorbidities.

Balloon Aortic Valvuloplasty (BAV) fills the gap and its successor Transcatheter Aortic Valve Implantation (TAVI) will be an option for the surgical high risk patients.

Otto et al N Engl J Med 1999;341:142–7

Ideal patientPalliative procedureBRIDGE TO SURGERYFrail patientsExtremely oldCompromised clinical status from concomitant CAD and other

extracardiac comorbidities.

Indications for BAV in adultsCardiogenic shock.Bridge to aortic valve surgery.Symptomatic critical AS requiring emergency noncardiac

surgery.Poor surgical candidate owing to high risk – age > 90 yrs.Diagnostic testing in low gradient/low output settingCongenital aortic stenosisRheumatic aortic stenosisPredilatation before TAVI

Circulation March 27, 2007 vol. 115 no. 12e334-e338

Goals A 100% increase in the aortic valve area.

Symptomatic improvement

Maximum pressure exerted on the valve leaflets during balloon inflation.

Proper balloon sizing.Optimal contact with the valve structures.

Final valve area is a determinant of the prognosis.

Why BAV is not successful as that of PBMV?

The results of BAV are limited by the pathology involved in the disease.

Degenerative AS is MC etiology.Chronic inflammatory process.Commissural fusion is not the predominant feature in majority of

older patients with calcific AS.Fracture of nodular calcium deposits – leaflet mobility improved –

increased valve opening – blood flow increased during LV contraction.

MECHANISMS OF ACTION

The effects of BAV on stenosed aortic valves are poorly understood, but several mechanisms appear likely.• Primarily, balloon-induced fracturing of calcified nodules creates

hinge points, which along with the creation of cleavage planes in collagenous stroma, results in improved leaflet flexibility and valve opening.

• Separation of fused leaflets is uncommon given its infrequent occurrence in this patient population with calcific aortic stenosis.

• Enhanced compliance or stretching of the adjacent annulus and calcified aortic root has also been suggested.

When maximally inflated, a 20-mm diameter balloon (occupying a 3.14 cm2 cross-sectional area) significantly enlarges the stenosed valve orifice by 3 mechanisms:

stretching of valve tissue, rupturing of commissural fusion and

breaking of calcific deposits. These last 2 mechanisms are the most effective, in both tricuspid and bicuspid forms of AS,to render the cusps more flexible .Stretching alone may give only a temporary increase in valve area with an elastic return of the leaflets to their initial stenosing position and may explain, at least in part, the occurrence of restenosis. Inflation of the balloon is well tolerated with no deleterious decrease in blood pressure in two-thirds of the cases because the balloon opens the commissures, allowing blood ejection through these openings. It does not produce calcific emboli, probably because calcium deposits remain imbedded in the leaflets, covered by the endothelium. Finally, it very infrequently produces acute severe aortic regurgitation. Careful choice of balloon size is necessary to obtain on effective opening; most often a 20-mm diameter balloon but sometimes a balloon up to 23 mm is used.

Am J Cardiol. 1988 Dec 1;62(17):1241-7http://www.ncbi.nlm.nih.gov/pubmed/3195485

Two approaches Retrograde approachAntegrade approach

The Retrograde approachFirst described by Lababidi in infants and children.Alain Cribier et al in adults.Procedure time < 1 hr.Less complications

Dr.Zuhdi Lababidi

Steps in the procedurePatient preparation.

Equipments – guidewires,sheath,balloon catheters.Retrograde crossing of the native aortic valve.Rapid ventricular pacing (RVP)Balloon inflation.Simultaneous gradients across the aortic valveHemostasis.

Patient preparation

Mild sedation with IV midazolam, local anaesthesia.Femoral arterial and venous access – 8F sheath.UFH 3000-5000IU IV at start of procedure.Coronary angiography in the same sitting, if needed coronary

intervention will also be done after BAV.Right heart catheterization – Swan Ganz thermodilution catheter.For TAVI – Supraaortic angiography – shallow LAO, followed by

abdominal and pelvic angiography.

Guidewire Extra stiff Amplatz 0.035”, 270 cm length guidewire

(Cook,Bjaeverskov,Denmark)All catheter exchanges.Stabilizing the valvuloplasty balloon during

Inflation.DeflationWithdrawal

Large pigtail shaped curve is formed at the distal end of the wire with a dull instrument to prevent ventricular perforation and to decrease ectopy.

Sheaths

8F arterial sheath is replaced over the extrastiff wire with a 10F,12F or

14F sheath, depending on the balloon catheter required.

Reduction in the profile of the devices – reduces local complications at

the femoral artery puncture site.

12-14 F sheaths – hemostasis by preclosing with a 10F Prostar device

(Prostar, Abbott Vascular, Redwood City,Ca).

10 F sheath – 8F angioseal device (Angioseal Vascular closure device,St

Jude Medical,Belgium) at the end of the procedure.

Balloon catheters

Tyshak balloon – retrograde techniqueInoue balloon – antegrade technique

Double balloon technique – antegrade

Catheters /Balloons Sheath size/ length of balloons

Double sized Cribier Letac catheters. 12-14 F

Z med II balloon catheter (Numed Inc.,Hokinton NY, USA). 12-14 F

Cristal balloons (Balt Extrusion,Montmorency,France) 10 F23 mm diameter balloons(usually used) 45 mm

25 mm diameter balloon 50 mm20 mm diameter balloon (if < 19 mm on echocardiography,

densely calcified)45 mm

25 mm diameter balloon (if aortic annulus diameter is >24 mm, 25% cases)

Retrograde crossing of the aortic valve AL -2 commonly used.Dual multilumen or pigtail catheter – peripheral augmentation is absent. Straight tip, fixed core ,0.035” guide wire.40LAO – catheter positioned at the rim of the valve.Catheter is slowly pulled back, firm clockwise rotation maintained to direct the

catheter tip toward the centre of the valve plane.Guidewire is carefully moved in and out of the catheter tip, sequentially mapping

the valve surface and exploring the valve orifice.Once as the wire crosses, the catheter positioned at the middle of LV.Transvalvular gradient is obtained from the side arm of the femoral sheath.Cardiac output measured.Aortic valve area by Gorlin’s equation.

Rapid ventricular pacing (RVP)6F temporary bipolar pacing lead – RV posterior wallPulse generator – 200 to 220 beats/min

Effective pacing is – precipitous fall in blood pressure to at least 50 mm Hg.

Initial 200/min – no response – increase to 220/min

If 2:1 block is seen,rate is reduced to 180 beats/min or modify the lead position.

Demand mode at 80 /min - in case of VAGAL response, AV conduction interruption leading to bradycardia or asystole in repsonse to balloon inflation.

In the past, before the use of RVP, always challenging to maintain the balloon in the optimal position during balloon inflation.

Figure 3. Rapid ventricular pacing stabilises the balloon when it is inflated. A pacing catheter is placed in the right ventricle. Rapid ventricular pacing is initiated at approximately 180–220 bpm and temporarily leads to a drop in systemic pressure. The balloon is inflated only after the pacing rate is reached and the blood pressure drops, and pacing is also continued until the balloon is deflated

Contrast solutionShort extension tubing with a three way stop cock attached is

connected to a hand held 30 ml leur lock syringe filled with diluted

contrast.

Contrast dilution at 15% contrast to 85% saline – reduces viscosity

- facilitates inflation, deflation cycles.

Further steps in BAVDiagnostic catheter is removed from the LV over the extrastiff wireLooped flexible segment of wire is carefully maintained in the LV

cavity.8F sheath is replaced by the 10F sheath over the extra stiff wire.After flushing the distal lumen and applying negative pressure on the

balloon port, the balloon catheter is mounted on the extra stiff wire.The system advanced into the aorta and allowed to rest above the

aortic valve.Partial inflation and then completely deflated one or more times to

completely purge it of air bubbles.

Cont…De airing of the balloon in the ascending aorta – lowest balloon profile

while crossing the aortic arch – decreasing the risk of atheromatous

plaque dislodgement and embolization.

Balloon catheter is advanced across the aortic valve centering the

valve between two markers.

The inflated balloon would tend to pop into the LV abruptly, striking

the apex,or would “eject” itself back into the aorta with the possibility

of disrupting atheromatous plaque,which would embolize.

Balloon inflationClear communication between the operators manipulating the balloon

catheter and the pacing device.RVP and simultaneous forward pressure on the balloon catheter and forward

pressure on the extra stiff wire help stabilize the balloon during inflation.Traction on the guidewire causes forward movement on the balloon.Pushing the guidewire displaces the balloon in the aortic direction

allowing for better positioning.RVP turned on, balloon inflation is started quickly and with enough

pressure to rapidly inflated the balloon as soon as the blood pressure falls.RVP continued for few seconds after the balloon reaches the maximum

inflation.Balloon is rapidly deflated, pacer is turned off, the balloon withdrawn from

the valve – clear coordination is required to allow restoration of antegrade flow while maintaining safe wire position in LV.

Figure 1. Balloon aortic valvuloplasty (BAV) via the retrograde approach. After correctly positioning across the stenotic valve the balloon is inflated with dilute contrast material. Note the temporary pacing wire in the right ventricle and the pigtail shapin g of the left ventricular wire

Figure 1. Balloon aortic valvuloplasty (BAV) via the retrograde approach. After correctly positioning across the stenotic valve the balloon is inflated with dilute contrast material. Note the temporary pacing wire in the right ventricle and the pigtail shaping of the left ventricular wire

Rapid balloon deflation and restoration of blood flow were important to minimize the time of hypoperfusion and hypotension.

Allow time for heart and BP to return to preinflated parameters before proceeding to inflate the balloon again.

Observe the wave form of the aortic pressure tracing, as well as heart rate response, rhythm and BP recovery.

A sudden change in waveform with loss of dicrotic notch or falling diastolic pressure could indicate the presence of severe AR.

Improvement of the pressure slope is suggestive of successful procedure.

Particular care must be taken as the deflated balloon is drawn through the sheath.

If resistance encountered, remove the catheter and sheath as a single unit.

Residual gradient – simultaneous measurement of pressure in the LV and in the aorta.

Significant gradient – next larger balloon may be chosen and the sequence is repeated.

Final stepsPull back gradient is obtained after the final balloon inflation.Remove the pacemaker.Cardiac output is measured.Final aortic valve area is calculated.Supraaortic angiography – for presence and severity of AR.If contrast not used,assessment can be by TTE.

Figure 2. Aortic and left ventricular traces pre- and post-valvuloplasty. The mean aortic pressure gradient has reduced significantly from 50 mmHg to 25 mmHg

Optimal resultDoubling of the valve area.Decreasing the gradient by 50% compared with the baseline value.

Immediate management after BAVManual compression is used for hemostasis at the venous entry site.Arterial hemostasis is achieved with closure device.Pneumatic pressure device in case of technical failure.Uncomplicated cases – discharge in 2 days.In case of severe CHF or cardiogenic shock – monitoring in ICU with

inotropic support is required.MC cause of hypotension – vagal reactions.Pericardial tamponade or retroperitoneal bleed not to be forgotten.

Antegrade approachBlock and colleaguesTransseptal approach.Severe peripheral vascular disease.

Dr.Peter.C.Block

Steps in the procedurePatient preparationTransseptal catheterizationCrossing the aortic valve.Atrial septostomyAntegrade balloon aortic valvuloplasty

Patient preparationMild IV sedation and local anaesthesia.Femoral venous access bilaterally obtained – 8F sheath in Rt. femoral

vein and 6F sheath in Lt. femoral vein.Coronary angiography through 6F sheath – brachial(or radial) artery.Pigtail placed above the aortic valve.Right heart catheterization and baseline hemodynamics measurements

are recorded.Left femoral vein access, bipolar pacing catheter –RV apex.RVP as needed.

Trans septal catheterization8F Mullins sheath.Brockenbrough needle via the right femoral vein.Crossing the septum – left lateral view.A pigtail catheter is positioned in the ascending aorta through out the procedure

for monitoring the blood pressure, as a reference marker for the trans septal puncture.

Middle third of a virtual line connecting the distal tip of the pigtail catheter adjacent to the aortic calcification and the posterior border of the heart.

After entry into LA is confirmed, then UFH 5000 IU is administered IV.7F Swan Ganz catheter which has an inner lumen compatible with a 0.035 inch

guidewire across the mitral valve into the LV Under fluoroscopic guidance - 40 RAO projection.

Trans aortic gradient - Swan Ganz in LV and pigtail in aorta.Aortic valve area calculated by Gorlin’s equation.

Crossing the aortic valveMullins sheath is advanced approx. 2cm beyond the mitral valve.Balloon of the Swan Ganz catheter is inflated and directed into the

LVOT approaching the native aortic valve.A 0.035’’ straight wire may facilitate crossing the aortic valve with the

balloon deflated, as the catheter pushed over the wire into the ascending aorta.

Wire is removed, and the balloon is reinflated.Catheter is advanced into the descending aorta and positioned at the

level of the distal aortic bifurcation with an Amplatz 0.035” ,360 cm long extrastiff guidewire.

Balloon is deflated and the catheter is removed.

The “essential” guidewire loop in the left ventricle

Large loop in the guidewire to be kept in the left ventricle.Straightening of the guidewire between the mitral valve and the aortic

valve can keep the mitral valve open, resulting in severe mitral regurgitation with hemodynamic deterioration.

Loop within the left ventricle is maintained with continuous monitoring at each step of the procedure.

8F sheath is replaced with a 10 F sheath for the subsequent balloon dilatation using the cristal balloon catheter (12F or 14F if NuMed balloons are used).

Atrial septostomyThe atrial septum is dilated with an 8mm diameter balloon septostomy

catheter through the 10 F sheath in the right femoral vein.

Diluted solution of contrast media:saline (15:85) is used with a 10 ml

syringe for atleast two balloon inflations of 30 seconds each.

Antegrade Balloon Aortic ValvuloplastySame balloon catheters are used as for retrograde approach.Dilatation of the aortic valve is done preferentially with the 23 mm

diameter balloon, which is advanced through the 10 F sheath and positioned across the aortic valve, while the loop is maintained in the LV.

Same steps as in retrograde technique.Not feasible to measure the gradient after inflations of each diameter

of balloon with this technique.Aortic pressure waveform for the hemodynamic result.

If a significant fall in diastolic pressure does not occur, then the next

larger balloon size can be chosen.

When two or three inflations using the largest selected balloon size are

completed, the balloon catheter is removed.

A 6F pigtail catheter is advanced over the extrastiff wire and

positioned over the arch so that the wire can be removed shielded by

the catheter, thus avoiding injury to the aorta or the mitral valve.

Final gradient – pigtail in the LV and other catheter in the aorta.Supra aortic angiogram can be obtained.Pacing catheter can be removed if there is no AV conduction defect.Swan Ganz catheter for the final hemodynamic results.Hemotasis is obtained by manual compression over the artery and the

vein after sheath removal.Bed rest for 24 hours.ICU monitoring required for patients who presented in caridogenic

shock.

Results using contemporary BAV techniques.

141 consecutive patients

Severe Aortic stenosis – high risk for surgery or inoperable

January 2002 to April 2005

Average age was 80.3±10 years.

45 % were women

NYHA IV -80%

LVEF < 30% - 28%

Emergency procedure in cardiogenic shock – 5.6% cases

Retrograde approach in 95% of the cases.

Largest balloon used was 23 mm balloon size – 84% of the procedures.

Agatiello C,Eltchaninoff H et al.Arch Mal Coeur 99;195-200:2006.

Results Immediate resultsIncrease in aortic valve area from 0.59± 0.19 to 1.02± 0.34 cm² (p<0.001)

Decrease in transvalvular gradient from 49.3± 21.2 to 22.2± 11.8 mm Hg (p<0.001)

Post BAV AR grade 2 – 14%, grade 3 – 3.5%,grade 4 1.4 % cases.

Death – 6 patients (4%)

Nonfatal severe complications – 9 patients (6%) - 2 transient strokes,5 complete AV block,2 severe AR.Vascular complications – 8,no surgical repair.

Discharge from the hospital was at 5.6± 3 days.

Clinically apparent neurological deficit - < 2%.

Embolization of atheromatous debris – rare.

Agatiello C,Eltchaninoff H et al. Arch Mal Coeur 99;195-200:2006.

Comparisons of complication rates in the Rouen Series and in the Mansfield Registry

Complications Mansfield Scientific Aortic Valvuloplasty Registry

1986-1988(N=492)

Rouen Series2002-2005(N=141)

Procedural death 2(4.9%) 3 (2.1%)Post procedural death (<7 days) 12(2.6%) 3(2.1%)

Cerebral embolic events 11(2.2%) 2(1.4%)Transient ischemic attacks 5(1.1%) 0(0%)

Ventricular perforation with tamponade

11(2.2%) 0(0%)

Severe AR 5(1.1%) 2(1.4%)Vascular complications (surgical

repair)27(5.5%) 0(0%)

Non fatal arrhythmias 5(1.1%) 5(3.5%)MI,sepsis,renal failure 8(1.6%) 1(1%)

Non calcific aortic stenosisPredominantly fibrotic – well suited for BAV.Procedure effective in 80-90% cases.Mortality rate of approx. 0.7%.Survival at 8 yrs - 95%Need for repeat intervention of 25% at 4yrs and 50% at 8 yrs.Rosenfeld et al –

no deaths,no embolic events.Intermediate follow up at 38 months - 50% patients required no

further intervention.

Current perspectives of BAV No Class I or IIA Recommendations for BAV.Class II B Recommendations for adult patients with severe AS are 1.hemodynamic unstable patients, candidates for bridge to surgery.2.as a palliative procedure for patients with severe comorbid

conditions which would preclude AVR.3.criticalsymptomatic AS4.contributing role of AS to dyspnea in patients with severe lung

disease.5.to assess myocardial contractile reserve in patients with lowgradient

or low EF.