Transcatheter aortic valve implantation (TAVI): an example of how to organise a TAVI programme

Transcription

1 original article Transcatheter aortic valve implantation (TAVI): an example of how to organise a TAVI programme J M ten Berg R Heijmen As the population ages, aortic valve stenosis becomes more prevalent. Patients who are symptomatic due to aortic valve stenosis have a severely diminished life expectancy and are, therefore, candidates for surgical aortic valve replacement. 1 That said, many of these patients (estimated up to one-third) do not undergo surgery, mainly because of the presence of severe comorbidities and the associated surgical risk. 2 This group of high-risk patients may be candidates for the recently developed transcatheter aortic valve implantation (TAVI) strategies In this article, we describe the decision-making process and how we perform the procedure in our clinic with a focus on the multidisciplinary approach we use. Catheter laboratory equipment Following thorough training in a skills lab and onsite support from a demonstrator (in the first 10 cases), we started to perform TAVI with the transfemoral approach using the CoreValve system (Medtronic Inc, Minneapolis, MN, USA) in June Since then, our TAVI programme has expanded to also include the SAPIEN valve (Edwards Lifesciences, Irvine, CA, USA) using the transapical approach. In our clinic, both operators (interventional cardiologist and cardiothoracic surgeon) were trained to use the CoreValve and the SAPIEN systems and both were trained in all the necessary associated procedures, including puncture techniques, valve crossing, valve placement etc. The only procedure solely performed by the cardiothoracic surgeon is the placement of the left anterolateral mini-thoracotomy. To help facilitate these procedures, we are currently developing a new, fully equipped, hybrid operating room at our facility. Until this is complete, we perform these procedures in the catheterisation laboratory, as the use of fluoroscopy is crucial. Patient selection The selection of patients who are candidates for TAVI is very important. The decisionmaking process needs to be done within a multidisciplinary team, consisting of interventional cardiologists, cardiothoracic surgeons, echocardiographers, and dedicated cardiac anaesthesiologists. Initially, patient Baseline requirements for evaluation in the heart team Clinical data (e.g. severity of symptoms, NYHA class) Data on co-morbidities (e.g. renal function and lung disease [FEV 1 ]) Life expectancy > 1 year TTE to evaluate the severity of the aortic valve stenosis as well as mitral valve disease. If needed, low-dose dobutamine echo to exclude pseudo aortic valve stenosis Recent (< 1 year) coronary and left ventricular angiogram Pulmonary pressure based on invasive measurement or echocardiography Visualization of the aorta ascendens (angiography or CT) STS score and EuroSCORE Additional requirements for evaluation in the transcatheter valve team Measurement of annulus size initially by TEE Visualisation of size, calcification and tortuosity of iliac and femoral arteries Calcification of the aortic arch (angiography, CT angiogram, MR angiogram) jurriën M TEN BERG ben swinkels GIJS MAST Department of Cardiology robin HEIJMEN TOM de kroon Department of Cardiothoracic Surgery St Antonius Hospital, Nieuwegein, the Netherlands Table 1 Requirements for evaluation CT, computed tomography; FEV 1, forced volume vital capacity; MR, magnetic resonance; NYHA, New York Heart Association; STS, Society of Thoracic Surgeons; EuroSCORE, European System for Cardiac Operative Risk Evaluation; TTE, transthoracic echocardiography; TEE, transoesophageal echocardiography 3

2 fig. 1 SAPIEN device fig. 2 CoreValve device data (including regional and extra-regional referrals) are discussed in the heart team (Table 1). Following this, and only when considered unsuitable for conventional aortic valve surgery, patients are referred to the transcatheter valve team. This team consists of two interventional cardiologists and two cardiothoracic surgeons who decide on the suitability of TAVI as well as the best approach (transfemoral or transapical; see Table 1 for additional requirements). All candidates for TAVI are seen in the outpatient clinic by an interventional cardiologist or cardiothoracic surgeon as well as an anaesthesiologist from the team to assess the life expectancy and the frailty of the patient, and to discuss with the patient and his/her family the risks associated with the procedure. At the same time, it is also important to highlight that surgery, in the event of complications during TAVI, is not an option for patients who have been previously denied surgery. In patients with cerebral disease (e.g. Alzheimer s disease), the evaluation from a neurologist and/or geriatrician is also taken into consideration. Throughout the decision-making process we do not follow strict criteria based on the STS score or EuroSCORE alone. 11,12 These scores were not developed for high-risk aortic valve replacement in patients (most high-risk patients were excluded from the original scores STS or EuroSCORE) and they can overestimate the actual mortality. Importantly, they do not include factors such as severe pulmonary fibrosis, a porcelain aorta or the frailty of the patient. Therefore, we consider a range of factors in the decision-making process and consider clinical judgment of the utmost importance. In addition, we do not accept patients for TAVI purely based on the personal preference of the patient. Which TAVI valve to use There are currently two valves commercially available: the balloon-expandable SAPIEN device which comes in two sizes (23 mm valve for annulus sizes up to 21 mm, and 26 mm valve for annulus sizes up to 25 mm; Figure 1) and the CoreValve system, consisting of a self-expanding valved frame which also comes in two sizes (26 mm stent for annulus sizes up to 23 mm, and 29 mm stent for annulus sizes up to 27 mm; Figure 2). As the CoreValve frame anchors in the ascending aorta, it should not be larger than 45 mm. The selection of the TAVI valve and the approach (transfemoral or transapical) is based on size, calcification and tortuosity of the femoral and iliac arteries, the calcification 4

3 of the aortic arch and the size of the annulus. If the size of the peripheral arteries is < 7 mm or if they are heavily calcified or tortuous, the apical approach is chosen. If the annulus size (measured by transesophageal echocardiogram [TEE] in a 3-chamber view; Figure 3) is > 25 mm, a CoreValve stent-valve prosthesis is chosen. In exceptional cases where the peripherals are < 6 mm and the annulus size is > 25 mm, a subclavian approach with the CoreValve stent-valve prosthesis is chosen. As the size of the delivery catheters will decrease in the near future (CoreValve 16 Fr and SAPIEN 18 Fr), the decision of which route to use and what valve to place may also change. The procedure: which approach to use? Transfemoral approach The procedures are performed in a catheterisation laboratory as optimal fluoroscopy during the procedure is crucial. A cardiologist and a catheter-skilled cardiothoracic surgeon conduct all procedures together (cover picture). They perform all steps of the procedure such as puncture of the femoral artery, valve crossing and placement of the valve in an alternating pattern. All procedures are performed under general anaesthesia administered by one of the dedicated anaesthesiologists in the team. In all patients, the TEE is used to help guide valve placement. The femoral artery is punctured (we do not use echoguidance) and a Prostar device (Perclose Inc., Menlo Park, CA, USA) is inserted. Then, using fluoroscopy to guide, an 18 Fr sheath is placed following administration of heparin (monitored at an activated clotting time [ACT] of 250 seconds). A final sizing of the annulus is performed by TEE before the CoreValve is loaded in the delivery catheter. A temporary balloon-tipped pacemaker lead is placed, via the jugular vein, in the right ventricular apex. Balloon dilatation (size of the balloon based on the size of the annulus) is performed under rapid pacing (180 bpm) to avoid slippage of the balloon. Maximal deployment (expansion) of the balloon has to be obtained (no residual waste). Balloon dilatation is performed just before the valve is successfully loaded to keep the time between valve dilatation and CoreValve frame placement to a minimum and prevent risk of haemodynamic deterioration of the patient. Valve placement is based on angiographic markers (calcium in the sinus, pigtail in the right coronary sinus) and echo markers making sure that the stent lands just above the base of the anterior mitral leaflet (Figure 4). At this point, we try to place the CoreValve as high within the left ventricular outflow tract as possible (max 6 mm below the annulus) to avoid high grade conduction abnormalities. Aortic valve LV Left ventricle PMVL Left atrium Annulus (=24 mm) AMVL LA CoreValve Right ventricle Aortic valve Ascending aorta fig. 3 TEE 3-chamber view fig. 4 TEE CoreValve 5

4 regurgitation is evaluated using TEE and angiography. Balloon dilatation of the stent with a bigger balloon is only performed if more than moderate regurgitation persists beyond 10 minutes after placement. In most cases, balloon dilatation of the CoreValve is not necessary as the regurgitation decreases over time due to the radial force of the device. After an uncomplicated procedure, the patient is usually extubated within 60 minutes. A permanent pacemaker is placed in all patients who develop any high-grade atrioventricular (AV) block the day after the procedure. TEE is performed the day after placement and patients stay in intensive care for at least 24 hours. They are admitted for at least 3 days to capture late complications such as conduction abnormalities. After discharge, all patients are seen in the outpatient clinic by one of the cardiologists at 6 weeks, 3, 6 and 12 months, and yearly thereafter; transthoracic echocardiography (TTE) is performed at each visits. Transapical approach In contrast to the transfemoral route, during a transapical procedure fluoroscopy is usually limited to a fixed position perpendicular to the aortic annulus displaying all relevant areas together due to the short distance between apex and annulus. Since there are no available data showing a benefit for either approach, we randomly assign our patients to increase our experience in both techniques, unless circumstances preclude the transfemoral or transapical route. Such circumstances include peripheral vascular disease, atheromatous aortic arch, severe chronic obstructive pulmonary disease, open wound or the aortic annulus size. Similar to the transfemoral approach, this procedure is performed by both the cardiothoracic surgeon and interventional cardiologist working closely together. The patient is placed under general anaesthetic with normal ventilation (i.e. no single lung ventilation is required). At first, TEE is used to measure the aortic annulus size and to ensure that it will, at least, accommodate the largest available valve size (aortic annulus < 24.5 mm for the 26 mm SAPIEN valve). Once confirmed, the appropriate valve is unpacked and prepared for implantation. A left anterolateral mini-thoracotomy is placed in the fifth intercostal space. Using minimal rib spreading, the apex of the left ventricle can be palpated. If required, the next intercostal space can be opened through the same skin incision. The pericardium is cut longitudinally and traction sutures are placed, which also can be used to distract the apex downwards to optimise exposure. In the case of a redo procedure, intrapericardial adhesions should be cleared at the apex. Using palpation of the anterior septum, the left anterior descending artery can be determined and a location is chosen slightly lateral and anterior to the true apex. Two purse-string sutures (Prolene 2-0, large needle) with interrupted Teflon pledgets are carefully placed sufficiently deep without penetrating the ventricular cavity. There is limited additional space for temporary epicardial pacemaker leads, so we prefer to use a transjugular venous lead. Prior to valve introduction, the haemodynamic response to rapid pacing is tested. Following administration of 5000 IU of heparin (aim ACT 250 seconds), a pigtail catheter is introduced transfemorally and positioned in the right coronary sinus. In the case of poor left ventricular function, a transvenous guidewire can be placed in advance to allow immediate cannulation for temporary extracorporeal support when needed. Next, the apex is punctured and a 6 Fr sheath is placed inside the ventricle followed by a stiff guidewire across the aortic valve and aortic arch towards the abdominal aorta. We prefer to skip the 14 Fr sheath used for balloon dilatation, and 6

5 introduce the 26 Fr transapical delivery sheath immediately to reduce blood loss while exchanging the various sheaths. The largebore sheath is adequately de-aired. Angiography clearly illustrates the aortic root and the C-arm is positioned accordingly. Next, balloon valvuloplasty (diameter, 20 mm) is performed during rapid ventricular pacing. The loader containing the crimped valve, the orientation of which is thoroughly checked, is introduced carefully and positioned in the annulus. During rapid pacing, the balloon is inflated halfway, followed by angiography. Any necessary position changes can still be made, after which the balloon is fully expanded and the valve placed. TEE, as well as angiography, is employed to assess valve function immediately, and again within the next half hour. When considered adequate, the apical sheath is removed and the apex securely closed using the purse-string sutures. We prefer to use rapid pacing, and hence temporary haemodynamic cessation, while closing the apex to prevent accidental tearing with potential dramatic consequences. Following standard closure of the thoracotomy, leaving one intrapleural drain, the patient is usually extubated within 1 hour. Results Between June 2007 and September 2009, a total of 95 patients were referred to our team to evaluate the possibility of a percutaneous Baseline characteristics of TAVI patients (n=73) Values are presented as mean ± SD or n (%) Mean age (yrs) 81.1 ± (9.6) 85 < (31.5) 80 < (21.9) < (37.0) Male 29 (39.7) Logistic EuroSCORE 22.0 ± 15.2 Standard EuroSCORE 10 ± 3 STS score 6.6 ± 6.2 History of: Ischaemic stroke 5 (6.8) Recent myocardial infarction* 0 (0.0) Old myocardial infarction** 12 (16.4) PCI 23 (31.5) Balloon aortic valve plasty 6 (8.2) CABG 21 (28.8) Re-CABG 3 (4.1) Biological AVR 1 (1.4) Cardiac surgery*** 22 (30.1) Body mass index (kg/m 2 ) 27 ± 5 NYHA Class I 0 (0.0) II 1 (1.4) III 59 (80.8) IV 13 (17.8) Hypertension (n; %) 29 (39.7) Severe pulmonary hypertension 15 (20.5) Peripheral arterial disease 15 (20.5) Carotid disease 7 (9.6) Paroxysmal atrial fibrillation 6 (8.2) Chronic/permanent atrial fibrillation 13 (17.8) Chronic lung disease 21 (28.8) Serum creatinine (µmol/l/mg/dl) 108 ± 46 / 1.2 ± 0.5 Dialysis 0 (0.0) Type 1 diabetes 4 (5.5) Type 2 diabetes 11 (15.1) Aortic annulus size (mm) TTE 21.8 ± 1.6 TEE 22.8 ± 1.6 Transfemoral approach 56 (76.7) (all CoreValve) Transapical approach 17 (23.3) (all SAPIEN) CoreValve prosthesis size 26 mm 33 (45.2) 29 mm 23 (31.5) SAPIEN prosthesis size 23 mm 2 (2.7) 26 mm 15 (20.5) Table 2 Baseline characteristics of TAVI patients (n=73) TAVI, transcatheter aortic valve implantation; PCI, percutaneous coronary intervention; CABG, coronary artery bypass graft; EuroSCORE, European System for Cardiac Operative Risk Evaluation; AVR, aortic valve replacement; NYHA, New York Heart Association; STS, Society of Thoracic Surgeons; TTE, transthoracic echocardiography; TEE, transoesophageal echocardiography. * 6 weeks before TAVI; **> 6 weeks before TAVI; ***Requiring opening of the pericardium; Systolic pulmonary artery pressure > 60 mmhg; Claudication, surgical or percutaneous intervention to the extremities, excluding carotid disease; Transient ischaemic attack, carotid endarterectomy, carotid occlusion or > 50% carotid stenosis. 7

6 Table 3 Echocardiographic data of patients 1 week before and 1 week after TAVI (n=73) TAVI, transcatheter aortic valve implantation; PAP, pulmonary artery pressure Table 4 Complications after TAVI TAVI, transcatheter aortic valve implantation intervention. Patients were referred from 25 centres in the Netherlands and from two centres outside the Netherlands. Of these, 13 patients were considered surgical candidates; 11 patients were operated on and two died while on the waiting list. In five patients, only balloon angioplasty was performed as these patients were considered unsuitable for TAVI due to a severely compromised clinical condition. Two of these patients died early after balloon angioplasty. In 73 patients, TAVI was performed. The clinical and echocardiographic characteristics of the patients at baseline, and one week prior to Echocardiographic data of patients 1 week before and 1 week after TAVI (n=73) Values are presented as mean ± SD or n (%) Before TAVI After TAVI Left ventricular ejection fraction 50% 49 (67.1) 54 (74.0) 30 < 50% 16 (21.9) 11 (15.1) < 30% 8 (11.0) 3 (4.1) Unknown 0 (0.0) 5 (6.8) Left ventricular hypertrophy No 5 (6.8) 5 (6.8) Mild 27 (37.0) 31 (42.5) Moderate 30 (41.1) 20 (27.4) Severe 11 (15.1) 9 (12.3) Unknown 0 (0.0) 8 (11.0) Maximum gradient (mmhg) 73.6 ± ± 8.4 Unknown 0 (0.0) 6 (8.2) Aortic valve area (cm 2 ) 0.69 ± ± 0.9 Unknown 0 (0.0) 69 (94.5) Aortic regurgitation No 30 (41.1) 32 (43.8) Mild 32 (43.8) 32 (43.8) Moderate 10 (13.7) 5 (6.8) Severe 1 (1.4) 0 (0.0) Unknown 0 (0.0) 4 (5.5) Systolic PAP (mmhg) 44.5 ± ± 12.1 Unknown 5 (6.8) 31 (42.5) and one week following TAVI are summarised in Tables 2 and 3, respectively. The number of patients who died, suffered an ischaemic stroke, or underwent pacemaker implantation because of third-degree AV block after TAVI are summarised in Table 4, and the causes of death in Table 5. Conclusions TAVI is a new treatment option for those symptomatic patients who are not surgical candidates or in whom the risk of complications during conventional surgery is deemed to be too high. As ongoing trials will Complications after TAVI Values are presented as n (%) Complication Death Transfemoral Transapical approach approach (n=56) (n=17) During TAVI 0 (0.0) 0 (0.0) from TAVI / in hospital 8 (14.3) 2 (11.8) from TAVI or later if still in hospital 8 (14.3) 2 (11.8) Ischaemic stroke During TAVI 1(1.8) 0 (0.0) from TAVI / in hospital 6 (10.7) 0 (0.0) from TAVI or later if still in hospital 6 (10.7) 0 (0.0) Pacemaker implantation During TAVI 0 (0.0) 0 (0.0) from TAVI / in hospital 16 (28.6) 1 (5.9) from TAVI or later if still in hospital 16 (28.6) 1 (5.9) 8

7 Cause of death (< 30 days from TAVI or later if still in hospital) Cause of death Transfemoral Transapical Values are presented approach approach as n (%) (n=56) (n=17) Heart failure 0 (0.0) 1 (5.9) Multiple organ failure 0 (0.0) 1 (5.9) Myocardial infarction 1 (1.8) 0 (0.0) Ischaemic stroke 4 (7.1) 0 (0.0) Sepsis 1 (1.8) 0 (0.0) Pneumonia 1 (1.8) 0 (0.0) Ischaemic colitis 1 (1.8) 0 (0.0) demonstrate positive results of using TAVI in high-risk patients, even more patients will become candidates for this procedure. To obtain optimal results, the selection of candidate patients is crucial and we consider it essential that this is done in a multidisciplinary team including cardiologists, cardiothoracic surgeons and dedicated cardiac anaesthesiologists. In addition, the procedure itself should always be performed by the same multidisciplinary team, leading to a better overall outcome. Our results, thus far, are promising and comparable to those from recently presented registries, suggesting that our approach in performing TAVI is a valid one. Table 5 Cause of death (< 30 days from TAVI or later if still in hospital) TAVI, transcatheter aortic valve implantation Address for correspondence J. M ten Berg MD, PhD, FACC, FESC. Department of Cardiology, St. Antonius Hospital, PO Box 2500, 3435 CM Nieuwegein, the Netherlands berg03@antoniusziekenhuis.nl DISCLOSURES: The opinions and factual claims herein are solely those of the authors and do not neccesarily reflect those of the publisher, editor-in-chief, editorial board and supporting company. RH is a consultant to Medtronic, Inc. JtB, BS, EGM, and TdDK have no relevant disclosures. REFERENCES 1 Nkomo VT et al. Burden of valvular heart diseases: a population-based study. Lancet 2006;368(9540): Lung B et al. Decision-making in elderly patients with severe aortic stenosis: why are so many denied surgery? Eur Heart J 2005;26(24): Cribier A et al. Early experience with percutaneous transcatheter implantation of heart valve prosthesis for the treatment of end-stage inoperable patients with calcific aortic stenosis. J Am Coll Cardiol 2004;43(4): Grube E et al. Percutaneous implantation of the CoreValve self-expanding valve prosthesis in high-risk patients with aortic valve disease: the Siegburg first-in-man study. Circulation 2006;114(15): Grube E et al. Percutaneous aortic valve replacement for severe aortic stenosis in high-risk patients using the second- and current third-generation self-expanding CoreValve prosthesis: device success and 30-day clinical outcome. J Am Coll Cardiol 2007;50(1): Chiam PT, Ruiz CE. Percutaneous transcatheter aortic valve implantation: assessing results, judging outcomes, and planning trials: the interventionalist perspective. JACC Cardiovasc Interv 2008;1(4): Webb JG et al. Percutaneous aortic valve implantation retrograde from the femoral artery. Circulation 2006;113(6): Webb JG et al. Percutaneous transarterial aortic valve replacement in selected high-risk patients with aortic stenosis. Circulation 2007;116(7): Ye J, Cheung A et al. Six-month outcome of transapical transcatheter aortic valve implantation in the initial seven patients. Eur J Cardiothorac Surg 2007;31(1): Vahanian A et al. Transcatheter valve implantation for patients with aortic stenosis: a position statement from the European Association of Cardio-Thoracic Surgery (EACTS) and the European Society of Cardiology (ESC), in collaboration with the European Association of Percutaneous Cardiovascular Interventions (EAPCI). Eur Heart J 2008;29(11): Nashef SA et al. European system for cardiac operative risk evaluation (EuroSCORE). Eur J Cardiothorac Surg 1999;16(1): Shroyer AL et al. The Society of Thoracic Surgeons: 30-day operative mortality and morbidity risk models. Ann Thorac Surg 2003;75(6): ; discussion Let us know what you think of this issue us at confluence@axon-com.com or return the freepost comments card included in this issue. Your feedback is important to us! 9