Transcatheter Aortic Valve Implantation TAVI : Current Updates Magdy Mostafa, MD Professor of Cardio-Thoracic Surgery Ain-Shams University
• Europe in 2007 approved Edwards SAPIEN and CoreValve TAVI• It is described as a "runaway train“ phenomena in Europe.• TAVI procedures made up 1.2% of valve procedures in 2007,but are expected to exceed 30% in the first half of 2011 . ( Cardiology News Digital Network, Dec,2011 )• TAVI statistics presented during CardioEgypt 2012 showed thatit exceeded 51% in Europe in the last year.• USA in November 2011: Food and Drug Administration (FDA)approved TAVI after PARTNER clinical trial study is concluded .
March 1, 2012 AATS, STS , ACCF and SCAI representing cardiologists and cardiothoracic surgeons released initial recommendations for creating and maintaining transcatheter aortic valve replacement (TAVR) programs.• Cardiologists and cardiothoracic surgeons are the cornerstone forestablishing a successful program, noting that a program without bothspecialties would be fundamentally deficient.• Heart team concept that is led by the surgeon and interventionalcardiologist. In all TAVR procedures, the interventional cardiologist and surgeonmust both be present during the entire procedure ensuring joint participation andoptimal patient-centered care.( Tommaso et al., 2012 by the Society for Cardiovascular Angiography andInterventions, The Journal of Thoracic and Cardiovascular Surgery, The Annals ofThoracic Surgery, and The Journal of the American College of Cardiology )
The Team Approach for TAVICARDIOLOGISTS SURGEONS Anesthesiologists Imaging specialists (Echo, CT, MRI) (EACTS/ESC/EAPCI , Eur Heart J, 2008; 29: 1463-1470, Eur J Cardiothorac Surg 34 (2008) 1-8)
Where to perform TAVI? For optimal safety and results, a hybrid operating room with sophisticated fixedimaging is essential. This includes having the facilities to:1. Perform angiographic imaging,2. Provide cardiac anesthesia with transesophageal echocardiography ( TEE )3. Access to all preoperative diagnostic imaging.4. Having the ability to convert to an open operation with cardiopulmonary bypass.5. General anesthesia
Inclusion Criteria for TAVI After assessment by the “Team”1. Severe Symptomatic AS (valve area is < 1.0 cm² or < 0.6cm²/m²) & Pressure gradient > 50 mm Hg with normal cardiac output2. Life expectancy >1year3. Contraindication for surgery ,or High Risk for Surgery : Clinical judgement + EuroScore (logistic) > 20%; STS Score >10%4. AND/OR - Porcelain aorta - History of thoracic irradiation - Severe thoracic deformity - Patent coronary bypass (Alec Vahanian, 2008)
Access For TAVI• Femoral vein (Antigrade) : it is no longer used• Femoral artery ( Retrograde )• Left ventricular apex• Subclavian / axillary (left)• Ascending aorta ( NEW) ( Michael Mack, 2010 )
TAVI Approaches TATF Shorter timeLess invasive Less radiationPercutaneous Less contrastLocal anesthesia Easier delivery --- ---Delivery more difficult More invasiveMore stroke? Less skilled operatorsNot for all patients Less experience
Subclavian Direct Aortic• Minimally Diseased Vessel • Most Direct Access• Less Invasive Than TA • Less Invasive Than TA• Local Anesthesia Possible • Surgeons More Comfortable• Crosses Arch But Less With Access?Traumatic ?• Direct Access To Valve
Balloon aortic valvuloplasty is typically performed with a Tyshak balloon. Anangiogram is performed to confirm proper positioning of the balloon, and during ashort period of rapid ventricular pacing, the balloon is inflated.
Transcatheter transfemoral retrograde approach. The valve is advanced over a stiffguidewire into the aortic position in a retrograde manner. It is positioned such that60% of the valve is on the ventricular side, and 40% of the valve is on the aorticside of the annulus.
Transcatheter transfemoral approach – completion angiogram of the implantedaortic valve is shown. Note that the contrast filled aortic root and ascending aorta areclearly seen, along with the take-off of the right and left coronary arteries.
The cardiac apex is accessed and a transapical sheath is placed into the left ventricle. Thevalve is advanced over a stiff wire in an antegrade manner. It is positioned such that 50%of the valve lies on the ventricular side, and 50% of the valve lies on the aortic side.
A completion angiogram is performed after the transapical deployment of the valve.The implanted aortic valve is shown. The completion angiogram should not onlyconfirm that the aortic root, ascending aorta, and the coronary ostia are intact, butalso that the mitral valve apparatus has not been disrupted by the transapicalapproach.
Contra indications for TAVIGeneral contra indications 1.Aortic annulus <18mm or >27mm 2. Bicuspid valves 3. Heavy calcification in front of LM 4. LV ThrombusSpecific contraindications for transfemoral approachPeripheral arteries 1. Diameter < 8 - 9mm 2. Severe tortuosity /calcification 3. Aorto-Femoral by passAorta 1. Aneurysm of abdominal aorta with thrombosis 2. Severe angulation 3. Porcelain aorta 4. Severe atheroma of the archSpecific contraindications for transapical approach 1.Previous surgery of the LV using a patch 2. Calcified pericardium 3. Severe respiratory disease 4. Non-reachable apex (Alec Vahanian, 2008)
Diagnostic Workup for TAVI.Measurement of Ilio-Femoral diameters by Angio & MS CT.Measurements of Aortic Annulus diameter by TTE & MS CT.Study Aortic Calcification distribution by TTE & MS CT.Plane of Aortic Annulus by MS CT.Distance Annulus/ Coronary Ostia by MS CT
Plane of the Aortic Annulus/ MSCT Welt F G et al. Circulation 2011;124:2944-2948
MSCT :Distance Annulus /Coronary Ostia Welt F G et al. Circulation 2011;124:2944-2948
Differences between the Medtronic CoreValve and Edwards Sapien valve systems Medtronic CoreValve Edwards Sapien valveMinimum femoral artery 6.5 mm 7 mmdiameter requiredComposition Porcine pericardial with Bovine pericardial with steel nitinol stent stentDelivery system size required 18 French 18 French (Sapien XT only)* 22 French (23 mm valve) 24 French (26 mm valve)Native annulus size feasible for 19 mm to 27 mm 17 mm to 25 mmimplantMechanism of implantation Self-expanding Balloon expandableVentricular rhythm at time of Beating heart Rapid ventricular pacingimplant
Possible Complications post TAVI:1. Stroke: A. EARLY:Immediate ( 1st 24 hours ) post-procedural Thromboembolic risk may be due to:• Periprocedural hypotension.• Embolism of debris during valve implantation.• Thrombi can form on devices/ wires during the procedure.Newer devices that deflect or filter emboli are also currently being investigated.. (Tay et al.,JACC, Dec, 2011)
B. DelayedPersists up to the first 2 months after TAVI.The bioprosthesis itself may be a source of thromboemboli beforeendothelialization of the prosthesis is complete :1. Aggregation of platelet and fibrin on valve leaflet within a few hours after implantation.2. The native valve leaflets, may be fissured or denuded are left compressed adjacent to the stent frame, which again has thrombogenic consequences.3. Incomplete Endothelialization of stent struts. (Tay et al.,JACC, Dec, 2011)
Pathological Images ShowingIncomplete Endothelialization(A) Postmortem of a patient who died on day 25 from pulseless ventricular tachycardia.(B) Postmortem of a patient whodied on day 28 after implantationfrom stroke-related complications. Several stent struts are notendothelialized (black arrow) in thispatient. Areas with tissue ingrowth(white arrow) are also shown forcomparison. (Tay et al.,JACC, Dec, 2011)
2. Paravalvular leak:• Post TAVI moderate to major paravalvular leak varies between (4%–35%)• It results from inaccurate sizing of the native Aortic annulus.• This is partly due to intrinsic anatomic properties of the aortic root—the‘virtual ring’ is largely inhomogeneous, coursing through the muscularseptum, the membranous septum and the mitro-aortic curtain. ( Cerillo et al., 2012 )
3. New-onset AF after TAVI:• NOAF occurred in about one-third of the patients with no priorhistory of AF undergoing TAVI• The 2 factors associated with the new-onset AF after TAVI :1. Left atrial enlargement2. Use of the transapical approach.• NOAF was associated with a higher rate of stroke/systemic embolism, but not a higher mortality, at 30 days and at 1-year follow-up. ( Amat - Santos et al., JACC, Dec. 2011 & Lung et al., JACC, 2012 )
4. Atrioventricular block: Complete atrioventricular block requiring pacemaker implantation at ≤30 dayswas low (1.8% for the TF and 3.8% for TA approach), and it depends on thedepth and level of placement of the valve at the left ventricular outflow track. (Lung et al., JACC, 2012 )
5. Other major adverse events:• Major ventricular tachyarrhythmia (0%–4%)• Myocardial infarction (0%–15%)• Cardiac tamponade (2%–10%),• Conversion to surgery (0%–8%),• Vascular complication (8%–17%),• Valve-in-valve procedure (2%–12%),• Aortic dissection/perforation (0%–4%). (Yan et al., J Thorac Cardiovasc Surg 2010 )
Post TAVI Anticoagulation management• Dual antiplatelet therapy (DAPT) with clopidogrel and aspirinfor 3 to 6 months is a widely accepted strategy in (TAVI) patientsbut this approach is not evidence based. ( Lung et al., JACC Vol. 59, No. 2, 2012)• While the strategy of adding clopidogrel to aspirin for 3months after TAVI was not found to be superior to aspirin alone. ( Ussia et al, American J. of Cardiology, 2011)
Placement of AoRTic TraNscathetER Valve (PARTNER) clinical trial Study• This represents the first US 1: 1 randomized percutaneous aortic valve trial.• A total of 1058 Patient included in 2 Parallel cohort studies individuallypowered :cohort A compared surgical aortic valve replacement versus transcatheter aorticvalve implantation (TAVI) among high-risk operative candidates ( 700 Patient )cohort B examined outcomes in inoperable patients. ( 358 Patient )
One year follow-up of the multi-centre US PARTNER transcatheter heart valve study I. PARTNER cohort A : Included 700 elderly patients (median age 84.1) with severe aortic stenosis and a mean STS score of 11.8/logistic EuroSCORE 29.3 were randomized to either: TAVI or Conventional surgery at one of 25 centers. • 245 patients receiving the experimental device via transfemoral route • 105 via a transapical procedure • 350 conventional surgery Patients in the transapical group were slightly higher risk than patients in either the transfemoral-TAVI group or the aortic-valve-surgery group.
American College of Cardiology (ACC) 2011 US PARTNER cohort ATAVI vs surgery outcomes: End point TAVI Surgery p End point TAVI Surgery p Mortality Mortality 30 d 3.4 6.5 0.07 30 d 3.4 6.5 0.07 1y 24.2 26.8 0.44 1y 24.2 26.8 0.44 Major stroke Major stroke 30 d 3.8 2.1 0.20 30 y 1d 5.1 3.8 2.4 2.1 0.07 0.20 1Major vascular y 11.0 5.1 3.2 2.4 <0.001 0.07 complications, 30 d Major vascular 11.0 3.2 <0.001 complications, 309.3 Major bleeding d 19.5 <0.001 Major bleeding New-onset AF 8.6 9.3 16.0 19.5 0.006 <0.001 Moderate/severe New-onset AF 8.6 16.0 0.006 PR Moderate/severe PR 30 d 12.2 0.9 <0.001 30 y 1d 6.8 12.2 1.9 0.9 <0.001 <0.001 1y 6.8 1.9 <0.001
One year follow-up of the multi-centre US PARTNER transcatheter heart valve studyII . PARTNER cohort B :It enrolled 358 patients with severe aortic disease unable to undergosurgery at one of 21 centers and randomized them to either:• Transcatheter valve implantation (Transfemoral, Sapien Valve)or• Best medical care, including balloon valvuloplasty.
TAVI vs standard therapy at one year: Primary end pointsEnd point TAVI Standard (%) p (%)1-y all-cause death 30.7 50.7 <0.0011-y all-cause death or 42.5 71.6 <0.001repeat hospitalization ( Leon MB et al. N Engl J Med 2010 )
TAVI vs standard therapy secondary end pointsEnd point TAVI (%) Standard (%) p30-d major stroke 5.0 1.1 0.0630-d vascular complications 16.2 1.1 <0.0011-y cardiac death 19.6 41.9 <0.0011-y major bleeding 22.3 11.2 0.007Survivors: Cardiac symptoms at 1 y 25.2 58.0 <0.001 ( Leon MB et al. N Engl J Med 2010 )
One year follow-up of the multi-centre European PARTNER transcatheter heart valve study Procedural outcome. Lefèvre T et al. Eur Heart J 2011;32:148-157
One year follow-up of the multi-centre European PARTNER transcatheter heart valve study (A) Overall survival for transapical patients. (B) Overall survival for transfemoral patientsLefèvre T et al. Eur Heart J 2011;32:148-157
Why TA results may not be as good as TF !• Higher risk patients in TA * TF First programs bias against TA• Procedure “less mature” * Surgeons with lesser “wire skills” * TA started later and there still is less experience with TA• More invasive procedure, especially in high-risk patients Michael Mack, Southern Thoracic Surgical Association, 2010
European Multi-Center Experience Out of 1236 patients underwent TAVI using theEdwards SAPIEN valve, 158 patients (12.8%) thetransaortic approach was used Transaortic approach results :• No postoperative strokes• 30-day all-cause mortality rate of 7%• Major bleeding rate of 1.3%. (Bapat et al.,, STS meeting,2011)
"Transcatheter aortic valve replacement with Edwards SAPIEN valve viatransaortic route: European Multi-Center Experience" STS 2011•Initial protocol was to attempt: Transfemoral approach > Transapical > Transaortic.But now: Transfemoral approach > Transaortic access.• But why the Transaortic approach was not the first choice, given its excellentoutcomes, low risk of stroke. It is difficult to "sell" the transaortic approach to patients because it involves a 5-cm incision in the chest, either via a mini-sternotomy or a mini-thoracotomy, asopposed to a short incision at the groin. (Bapat et al.,, STS meeting,2011).
Conclusion• Heart team concept should be adopted in every TAVIprocedure• Transfemoral access need not be the default approach asno data exist from randomized clinical trials showing that it isbetter than the others .• ‘Indications are slipping’ which means that operablepatients with moderate or low risk score are getting TAVIwhen they should have surgery• Trans Aortic approach is a good and more safe alternativeto both Transfemoral and Transapical approaches.