European Association for Cardio-Thoracic Surgery 29th Annual Meeting 2015 Blog – Michael Seco

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Aortic Valve Repair

Atrio-Ventricular Valves

Heart Failure Surgery

Minimally Invasive Mitral Valve Surgery

Sutureless Aortic Valve Replacement

Aortic Valve Repair

Aortic root anatomy

• Reviews: de Kerchove et al. JTCVS 2015 & de Kerchove et al. ACS 2013

• Aortic root (aka functions aortic annulus) – lower limit is the ventricle-aortic junction (VAJ, aka surgical annulus) & upper limit is the sinotubular junction (STJ)

• Normal VAJ area changes during cardiac cycle – increased during isovolumetric contraction & ejection, decreased during isovolumetric relaxation, increased during diastole

• Normal aortic annulus is oval & becomes more circular with dilation

• The annulus is larger in a bicuspid AV than a tricuspid AV

• The annulus becomes progressively larger with increased degree of AR

Aortic insufficiency repair classification

• Boodhwani et al. JTCVS 2009

• type 1 – due to dilation of the AAo ± STJ ± sinuses of Valsalva ± VAJ or cusp perforation

• type 2 – due to leaflet prolapse (excessive cusp tissue or commissural disruption)

• type 3 – due to leaflet restriction (BAV, calcification, fibrosis, rheumatic)

Aortic annuloplasty

• Re-establishing normal annulus diameter is the basis for successful AV repair

• When you need to do an annuloplasty:

• Bicuspid AV annulus – 29-30mm

• Tricuspid AV annulus – 28mm

• STJ : VAJ ratio should also be between 1 – 1.5

• Surgical dissection down to the annulus in VSARR:

• NC sinus – limit is fibrous portion of the VAJ (aorto-mitral continuity)

• NC/RC commissure – limit is membranous septum

• RC sinus – limit is muscular septum (myocardium of interventricular septum & RVOT)

• RC/LC commissure – limit is muscular septum

• LC sinus – limit is roof of LA – the only area where dissection reaches the nadir of the leaflet hinge line

• Options for annuloplasty:

• Subcommissural annuloplasty (Cabrol stich)

Also increases valve coaption by closing the inter-leaflet triangles (sometimes used for this purpose instead of annuloplasty)

• Annuloplasty is not stable over time – recurrent dilation can occur in the portions between the plication sutures – Vallabhajosyula et al. ATS 2014 & Hanke et al. JTCVS 2009

• Also creates asymmetrical shape, abolishes normal physiology in the inter-leaflet triangles

• External ring annuloplasty

• teflon/Dacron ring

• expansible external ring – Lansac et al. MMCTS 2011

• Internal ring annuloplasty

• Dacron strip

• Novel preformed ring – 2yr follow-up showed good result – Mazzitelli et al. EJCTS 2015

• Ring is close to leaflet insertion ?impingement, ?does it induce fibrosis that could extend to the leaflet

Effective & geometric height

• standardised measurements used for cusp resuspension during VSARR

• effective height (eH) – distance between the aorta-ventricular (basal) plane & central caption level

• Schäfers et al. JTCVS 2006

• used as indicator of cusp prolapse

• requires a normal amount of cusp tissue i.e no cusp retraction (e.g. ageing & inflammatory conditions)

• geometric height (gH) – maximum tissue height of the cusp

• Schäfers et al. JTCVS 2013

• cusp retraction defined as ≤16mm in tricuspid AVs & ≤19mm in BAVs

repair of retracted cusps do not do well & should be replaced instead

AV leaflet repair techniques

• types of patches

• autologous – fresh, glutaraldehyde-treated

• xenograft – pericardium, anti-calcification, decellularised, ECM

• synthetic – Gore-Tex, synthetic ECM

• techniques

• partial cusp repair – perforation, fenestration, commissure, raphe, cusp extension, unicuspid/dysmorphic valve

• full cusp repair

• aortic valve reconstruction (Ozaki procedure)

• patch use is known to be associated with decreased durability of repair/recurrent AI

Aortic valve reconstruction

• Ozaki operation is method of aortic valve reconstruction

• Ozaki et al. ICTS 2011 & Ozaki et al. JTCVS 2014

• Video

• Originally used glutaraldehyde-treated autologous pericardium for reconstruction

• Cardiocel (bovine pericardium) has been used successfully in congenital heart surgery for 8 years

• Study looked at performing the Ozaki operation using Cardiocel in sheep

• Echo at 6 months showed valves functioning well

• Explant showed preserved structure & stability of the Cardiocel tissue

• Low rate of calcification

• Neo-intima formation & re-cellularisation with host cells

Haemodynamics of David procedure

• 3D aortic root geometry & flow dynamics were assessed during the cardiac cycle in pigs with native aortic root or David procedure

• The David root is exposed to high pressures & low shear stress for a longer time during the cardiac cycle than the native aortic root, which would favour degeneration

• However clinical outcomes have of the David have been very good – perhaps there is leaflet remodelling that occurs in response to this pressure

• Not presented specifically, but apparently when same model was applied to the Yacoub repair the haemodynamic profile was superior to the David & closer the native aortic root

Atrio-Ventricular Valves

Parachute ventricular partitioning

• Used to partition off & exclude an apical aneurysm & increase EF

• Nitinol-based PTFE covered parachute-like device

• Transfemoral delivery

• Guide catheter points at the landing zone in the ventricular apex, the device is deployed, & a balloon is used to expand the nitinol frame

Transcatheter Mitral Valve Implantation (TMVI)

• Number of differences in the MV compared to the AV that makes designing transcatheter devices challenging

• Differences in anatomy

• Larger size & D shape

• Complex subvavular apparatus

• Some cords insert into the leaflet body rather than the free margin, the anterior commissure is close to the AV,

• The MV is also close to the circumflex artery

• Differences in physiology

• MV separates low-resistance from high-resistance, whilst AV separates high-resistance from high-resistance

• MV has low-resistance inflow (diastole) & high-resistance outflow (systole)

• Annulus changes dimensions up to 40% in systole

• Both aetiology & affected structures are highly varied

• Differences in design priorities

• Aim to decrease or maintain the EOA, as opposed to maximising

• The height of the device affects risk of LVOTO

• The angle of the device to the AV also affects risk of LVOTO

• Size of ventricle affects how much room there is for the device

TMVI – CardiAQ (Edwards Lifesciences)

• Bovine pericardial trileaflet valve with intra-annular sealing skirt to minimise PVL

• Mostly sits in the LA to avoid risk of LVOTO

• Transeptal & transapical delivery

• Steps: Leaflet capture, vale delivery, valve expansion

• Used in 8 patients so far with good success rate, reduction of MR to trace/none, low gradient, trace/no PVL

• Currently undergoing FDA early feasibility study & CE mark study

• http://circinterventions.ahajournals.org/content/8/7/e002135.extract

TMVI – FORTIS Valve (Edwards Lifesciences)

• Bovine pericardial trileaflet valve, D shaped frame with circular valve

• Transapical delivery

• Steps: paddles partially deployed in ventricles, leaflets captured, flange release, valve released

• FDA early feasibility study initially stopped due to valve thrombus, though anticoagulant regimen revised & study restarted

• http://www.ncbi.nlm.nih.gov/pubmed/25256325

TMVI – Tiara Valve (Neovasc Inc)

• D shaped valve, anterior portion faces the aortic valve

• Steps: atrial skirt deployed first, device is centred & orientated, then ventricular skirt deployed

• Used in 7 patients in Canada in special access scheme with good success

• Currently undergoing the TIARA-I early feasibility study

• http://www.ncbi.nlm.nih.gov/pubmed/25256324

TMVI – Tendyne Valve (Tendyne)

• D shaped outer stent with circular inner stent, apically teathered

• Transapical delivery, performed mostly with live 3D echo

• Steps: valve deployed 80% in the atrium, device rotated to orientate correctly, withdrawn into the annulus, teather secured to the apical apex

• Optimal tension on the teather is still unclear, but based on PVL & strain

• 17 implants so far

• http://interventions.onlinejacc.org/article.aspx?articleid=1905024

• https://vimeo.com/124837177

TMVI – HighLife Procedure

• 2 step procedure:

• Sub-annular ring implantation

• Valve-in-ring implantation

• All chordae should be caught in the ring

• Ventricular part delivered first, then whole valve is pushed up into the annulus, then atrial part delivered

• Transapical or transatrial delivery

• Self centuring & self positioning on release

• First in man planned for next month

Tricuspid valve repair

• The TV tends to dilate in the anterior & posterior leaflet direction (I.e not in the septal leaflet direction)

• Bicuspidation of the tricuspid valve technique

• Mattress sutures from the mid point of the posterior leaflet to the mid point of the septal leaflet

• No difference in survival compared to annuloplasty

• Mitralign transcather device for tricuspid annuloplasty

• Insertion made using RF

• First insertion make around the posterior-septal commisure

• Device is sinched down 2 plegetted sutures & creates annuloplasty

• Max distance to sinch (I.e between sutures) is 2.8cm – the tricuspid annular tissue is more fragile than mitral annular tissue, & any more distance could be damaging

• Makes the posterior leaflet redundant

• Used in 10 patients worldwide

• Tricuspid valve repair using extra cellular matrix cylinder

Heart Failure Surgery

Heartmate III CE mark trial

• Uses Maglev technology to magnetically suspend the impeller (no hydrodynamic or mechanical bearings) – allows for wide range of flow, artificial pulse (hopefully less aortic insufficiency, blood stasis, fewer GI bleeds), more consistent pump gaps (hoping to reduce haemolysis & thrombosis)

• First in-human trial, prospective, non-randomised, n=60

• Mean age 59yrs, ischaemic aetiology in 44%

• All implants via median sternotomy

• Drive line externalised with silicone to skin interface in 96% (designed to reduce infection)

• 42% had concomitant procedures (valve operations, PFO, LAA occlusion)

• mean CPB time 84min (63-110)

• 30 day outcomes

• Bleeding 30%

Quite high due to strict definition (≥4 units in first 7 days, ≥1 unit after day 7)

• 12% required reoperation

• Stroke 4% – 1 patient had difficulty engaging inflow conduit; 1 ischaemic stroke from anaphylactic shock

• 8% right heart failure (2 requiring RVAD support)

• No device malfunction, thrombosis, haemolysis

• 98% survival (1 death in the ischaemic stroke patient)

• 6 month endpoint also met, awaiting CE mark approval

• In Viena (where study was) as soon as CE mark they will stop implant Heartmate II & only use III

Lavare cycle in the HeartWare HVAD

• Lavare cycle involves periodic speed modulation which may reduce blood stasis

• Lower speed (-200rpm) for 2 sec, then higher speed (+200rpm) for 1 sec, then baseline for 60sec, then cycle starts again

• Step 1 – large vortex results in ventricular washout

• Step 2 –

• Step 3 – large ventricular washout again then normalised flow

• ReVOLVE registry (n=248) analysis of the Lavare cycle

• Significantly fewer stroke, sepsis, RHF

• Other outcomes including survival were similar

• Usually turned on after the patient leaves the OR (in Vienna)

Novel inflow cannula implant technique

• LVAD results in servely disrupted blood flow in the LV – bloods flows to the ventriclar apex instead of the AV valve, increasing the risk of thrombosis

• Study used an ex vivo dilated porcine heart (non-beating) on ECMO 4.5L

• A cone shaped prosthetic tube was attached to the mitral valve annulus to funnel blood directly into the LVAD & avoid the disturbed flow in the LV

• Resulted in higher flow rate & more streamlined elliptical shaped flow

• Acute live animal experiment – successful implanted & weaned off CPB (onto VAD only) (animal had to be terminated at 1 hr due to ethics)

• Next step is chronic animal model

LVAD less invasive approaches

• Upper hemi-sternotomy + left thoracotomy approach possible

• Helps preserve sternum for later heart transplantation

• Alternative to hemi-sternotomy is right thoracotomy or right parasternal incision

• Disadvantage is the outflow graft has to cross the midline twice as it travels to aorta

• Disadvantage is more difficult access

• Advantage is sternum is even further preserved for heart transplantation

• Related paper: Maltais et al. ACS 2014

Minimally Invasive Mitral Valve Surgery

Debate for sternotomy approach – David Adams, Mount Siani Medical Center, NY

• Achieving 100% repair rate with no residual regurgitation is the most important priority

• Some studies of the mini-thoracotomy approach have compromised repair rate or an increased rate of residual MR (3 or 4+) post repair

• Handling complexities such as annular calcification is much more difficult through a mini-thoracotomy

• To achieve good outcomes with mini or robotic mitral surgery you need to be at a super-high volume centre, which most places are not

• Meta-analyses have found increased rate of stroke, possibly due to retrograde perfusion from femoral CPB cannulation

• Limited sternotomy is not as morbid as the traditional full sternotomy but provides the same full open access, & has smaller incision with good cosmesis

Debate for minimally invasive approach – Patrick Perier, Herz und Gefäß Klinik, Germany

• Mini-thoracotomy with direct vision still requires rib spreading which is still morbid & not as ‘minimally invasive’ as possible – so it should be done as port-access surgery with video vision

• The exact same repair techniques should be replicated with the mini-thoracotomy approach

• New programs need to be highly selective of simple patients at the beginning, then progressively add more complex repairs & concomitant procedures (e.g. AF) as they gain experience

Evidence on mini-mitrals – J Grau, Cleveland Clinic, USA

• Paper: Bolling et al. ATS 2010

• Minimum of 40 mitral operations per surgeon per year are needed to achieve an 80% repair rate (deemed minimum acceptable rate)

• Paper: Holzhey et al. Circulation 2013

• Learning curve for minimally invasive approach at very high volume centre (Leipzig) was 150-200 patients

• Learning curves are surgeon-specific as well, & some required re-mentoring

• Minimum of 50-100 mini-mitrals per year are needed to be proficient

• Very difficulty achieving this number as you need to be an expert in MV repair first, then expert in minimally invasive approach

Robotic-assisted mitral valve surgery

• Robotic assistance provides many advantages in visualisation, control and precision allowing for minimally invasive repair of the most complex valve

• Video by Didier Loulmet demonstrated repair techniques

• They use a fluorescence covered endoaortic balloon (for CPB) to facilitate positioning

• Paper: Yaffee et al. JTCVS 2015

• Video atlas of robotic mitral techniques

• Related systematic review: Seco et al. ATS 2013

Sutureless Aortic Valve Replacement

Intuity valve (Edwards)

• MIS AVR meta-analyses:

• lower mortality, fewer transfusion, shorter HLOS

• longer XC & CPB times

• http://www.ncbi.nlm.nih.gov/pubmed/25064516

• Intuity valve – essentially a Magna Ease valve (Edwards) combined with stainless steal stent & sealing cloth from the Sapien 3 valve

• CADENCE MIS trial http://www.ncbi.nlm.nih.gov/pubmed/25441065

• Intuity valve via upper hemi-sternotomy (n=51) vs. standard AVR via full sternotomy (n=49)

• 3 conversions to full sternotomy with scented bioprostheses – 2 unable to fit valve properly, 1 annulus tear

• 24% relative reduction in XC time (despite mini-incision, which usually increases XC time by 16%)

• mortality not significantly different

• PPM rate not significantly different, despite stent extending lower into the ventricle. Percival valve (similar sutureless valve) has higher PPM rate, but study had higher mean age than CADENCE-MIS (78 vs. 73), which may account for difference?

• increased rate of mild PVL – potentially due to improper sizing, not aggressively debriding annular calcification

• Intuity had significantly better EOA & gradients

Management of small aortic annulus

• retrospective study comparing stented valves, Manougian procedure, stentless Freestyle prosthesis, & sutureless Percival S valve in patients with annulus <21mm

• stentless group had significantly lower mean aortic gradient & higher EOA than other groups

this was a full root replacement with Freestyle graft, allowing for a larger prosthesis than the annulus

• the Trifecta valve (St Jude) had significantly lower gradients & higher EOA than perimount, magna ease & mitroflow prostheses

Timing of individual steps in SAVR

• aim to identify specific steps where time could be saved

• exposure (stating after XC + AV assessment) – 5.3mm (10min)

• resection (resection of AV leaflets + annulus decalcification + sizing) – 8.1mm (16%)

• suturing – 17.3mm (33%)

• tying – 9.1min (18%)

• declamping – 11.9min (23%)

• sutureless valves & knot tying devices have potential to significantly reduce time

• more experienced surgeons were faster