Transapical Aortic Valve Implantation: Therapy of Choice for Patients With Aortic Stenosis and Porcelain Aorta?

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1 Transapical Aortic Valve Implantation: Therapy of Choice for Patients With Aortic Stenosis and Porcelain Aorta? Jörg Kempfert, MD, Arnaud Van Linden, MD, Axel Linke, MD, PhD, Gerhard Schuler, MD, PhD, Ardawan Rastan, MD, PhD, Sven Lehmann, MD, Lucas Lehmkuhl, MD, Friedrich-Wilhelm Mohr, MD, PhD, and Thomas Walther, MD, PhD Clinics for Cardiac Surgery, Cardiology, and Radiology, University of Leipzig, Heart Center, Leipzig, Germany Background. Conventional aortic valve replacement can be technically challenging in patients with porcelain aorta and is associated with a high rate of stroke and mortality. Porcelain aorta is even sometimes seen as contraindication for surgery. Minimally invasive offpump transapical aortic valve implantation may be an optimal strategy to treat elderly patients with porcelain aorta requiring aortic valve replacement. Methods. Twenty-nine patients with severe aortic stenosis and porcelain aorta underwent transapical aortic valve implantation. Mean age was years (range, 64 to 93 years), with 65.5% female. Logistic EuroSCORE and the Society of Thoracic Surgeons score were 37.7% 18.1% and 12.8% 2.2%, respectively. Peripheral vascular disease (41.4%) and carotid artery stenosis (58.6%) were frequent, and 17.2% of patients had experienced a stroke previously. The majority of patients were redo cases (51.2%), and 10.3% were dependent on chronic hemodialysis. In 13.8% of all patients, intraoperatively detected porcelain aorta caused an attempt at conventional aortic valve replacement by means of sternotomy to be aborted. Results. All valves were implanted successfully without embolization or aortic dissection. All procedures were primarily performed off-pump, but 4 patients required secondary cardiopulmonary bypass as a result of complications. Median procedure time was 80 minutes, and median intensive care unit stay was 1 day. Stroke occurred in 1 patient only. Thirty-day mortality was 17.2%. Mild paravalvular leak was seen in 31.0%, and mild to moderate regurgitation occurred in 1 patient. Conclusions. Transapical aortic valve implantation is a promising approach to treat elderly patients with porcelain aorta requiring aortic valve replacement. It is associated with acceptable outcome and low stroke rates. (Ann Thorac Surg 2010;90: ) 2010 by The Society of Thoracic Surgeons Conventional aortic valve replacement (AVR) can be technically demanding and is associated with increased mortality and morbidity, especially as a result of the perioperative stroke risk in patients with an unclampable heavily calcified ascending aorta (porcelain aorta) [1 4]. Porcelain aorta is sometimes even seen as a contraindication for surgery in elderly high-risk patients in whom most surgeons will hesitate to perform an extended surgical procedure involving circulatory arrest and replacement of the ascending aorta. The number of elderly patients presenting with porcelain aorta and additional comorbidities requiring AVR may, however, increase in the future, owing to the increase in life expectancy. Accepted for publication June 14, Presented at the Poster Session of the Forty-sixth Annual Meeting of The Society of Thoracic Surgeons, Fort Lauderdale, FL, Jan 25 27, Address correspondence to Dr Walther, Universität Leipzig, Herzzentrum, Klinik für Herzchirurgie, Strümpellstrasse 39,Leipzig, 04299, Germany; walt@medizin.uni-leipzig.de. Coronary artery bypass grafting can be performed with a no-touch off-pump technique and facilitates an approach by which any aortic manipulations can be avoided. Even for mitral and tricuspid valve surgery alternative techniques using peripheral cannulation and a beating heart have been described, facilitating a clampless procedure [5]. Until recently, clamping of the aorta was unavoidable in aortic valve surgery. With the clinical introduction of transcatheter aortic valve implantation techniques [6 9], new minimally invasive options have now become available to treat this special patient subgroup. Transcatheter aortic valve implantation seems well suited for patients with porcelain aorta as it allows for beating-heart valve implantation without cardiopulmonary bypass (CPB) and most importantly without clamping of the ascending aorta. Although transfemoral retrograde transcatheter aortic valve implantation is feasible in patients with porcelain aorta [10], the transapical approach avoids the oftencalcified femoral and abdominal vessels in these patients and might be associated with a lower stroke rate owing to the fact that the antegrade technique requires strong 2010 by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc doi: /j.athoracsur

2 1458 KEMPFERT ET AL Ann Thorac Surg MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT 2010;90: manipulation around the often heavily calcified aortic arch. Patients and Methods Patients Between February 2006 and February 2009 a total of 210 high-risk elderly patients with severe aortic stenosis underwent transapical aortic valve implantation (TA- AVI) at our institution. The presence of a porcelain aorta was suspected by chest roentgenography or cardiac catheterization and then confirmed by multislice computed tomography scan (Fig 1). Twenty-nine patients were identified as having a true porcelain aorta. This group forms the study population. The mean age was years (range, 64 to 93 years), with 65.5% female. Logistic EuroSCORE and The Society of Thoracic Surgeons score were 37.7% 18.1% and 12.8% 2.2%, respectively. Preoperative characteristics of the patients are presented in Table 1. The majority of patients were redo cases (51.7%), and 13.8% had already had an aborted attempt of conventional AVR through means of a sternotomy because of intraoperatively detected porcelain aorta. All patients were discussed in an interdisciplinary team to decide on the best treatment option in each individual patient. After informed consent all patients underwent TA-AVI using the Edwards SAPIEN device (Edwards Lifescience, Irvine, CA). Approval was granted by the local Institutional Review Board. Implantation Technique All procedures were performed in a fully equipped hybrid operating room with a high-quality imaging system (Axiom Artis, Siemens Inc, Forchheim, Germany) by a specialized team involving cardiac surgeons, cardiologists, and cardiac anesthetists. Before skin incision a femoral safety net consisting of an arterial sheath and a venous wire was placed [11], and a CPB system was always available on standby and ready to use. Transapical aortic valve implantation was performed as previously described in detail [9]. Briefly, in all patients a left anterolateral minithoracotomy was performed in the fifth or sixth intercostal space, and the left Table 1. Preoperative Status Variable n 29 Age (y) (range 64 93) Female (n/%) 19/65.5 Redo procedure (n/%) 15/51.2 Logistic EuroSCORE (%) STS score (%) Left ventricular EF NYHA class Peripheral vascular disease (n/%) 12/41.4 Hypertension (n/%) 29/100 Diabetes mellitus (n/%) 8/27.6 Carotid artery stenosis (n/%) 10/34.5 Status after stroke (n/%) 5/17.2 Status after aborted sternotomy (n/%) 4/13.8 Chronic lung disease (n/%) 18/62.1 Renal disease (GFR 60 ml/h) (n/%) 17/58.6 Mean aortic gradient (mm Hg) Maximal aortic gradient (mm Hg) Concomitant aortic regurgitation (n/%) 23/79.3 EF ejection fraction; GFR glomerular filtration rate; NYHA New York Heart Association; STS Society of Thoracic Surgeons. ventricular apex was exposed and secured by two 2-0 Prolene (Ethicon, Somerville, NJ) pursestring sutures. After apical puncture a soft guidewire was advanced in antegrade fashion across the stenotic aortic valve followed by a soft-tip 14F sheath. With the help of a right Judkins catheter a superstiff guidewire was passed into the descending aorta with minimal manipulations around the aortic arch only. Balloon valvuloplasty (Fig 2A) was performed during rapid ventricular pacing, then the apical application sheath was inserted, and the valve was positioned and implanted using a stepwise approach under a second interval of rapid pacing (Fig 2B). Hemodynamic performance of the implanted valve was assessed by transesophageal echocardiography and angiography (Fig 2C) in parallel to routine apical and chest wall closure. After the procedure all patients were transferred to the postanesthetic recovery room for early extubation after an ultrafast-track protocol. Statistics For statistical analysis data were 100% complete. Continuous variables are expressed as mean standard deviation for Gaussian distribution and otherwise median values only. Categorical data are given as proportions. Follow-Up All patients had echocardiographic examination before discharge, and follow-up data are available up to 1 year. Fig 1. Postoperative three-dimensional reconstruction (A) and computed tomographic scan (B) of porcelain aorta. Results All valves were implanted successfully without embolization or aortic dissection (Fig 3). There was no severe paravalvular leak observed, and only 1 patient demon-

3 Ann Thorac Surg KEMPFERT ET AL 2010;90: MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT 1459 Fig 2. Intraoperative balloon valvuloplasty (A), valve implantation (B), and final angiographic result (C) of porcelain aorta. strated a moderate paravalvular insufficiency. Angiography and transesophageal echocardiography revealed a trivial to mild paravalvular leak in 31.0% of all patients. Antegrade hemodynamic performance of the valves was excellent with a mean transvalvular gradient of mm Hg. Twelve patients received a 23-mm valve, and 17, a 26-mm SAPIEN prosthesis. Mean oversizing was 2.4 mm (Table 2). The median duration of the procedure was 80 minutes. All procedures were initially started off-pump, but in 4 patients conversion to CPB was necessary using the femoral safety net: 2 patients (both with left ventricular ejection fraction 0.30) required temporary support owing to hemodynamic instability, but could be easily weaned after valve implantation. In 1 patient CPB was used to unload the ventricle to solve apical bleeding. The last patient required CPB support because of an occlusion of the left mainstem artery. This patient was converted to a full sternotomy and received two bypass grafts using the on-pump beating heart technique. The patient recovered and was discharged in good condition. Median intensive care unit stay was 1 day, and 9 patients had acute renal failure requiring temporary hemodialysis. Five patients required new pacemaker implantation as a result of atrioventricular block. Stroke occurred in only 1 patient with hemiplegia and cerebral infarction detected in a postoperative computed tomography scan. The hemiplegia was temporary, and after rehabilitation a complete recovery was observed. Overall 30-day mortality was 17.2% (Table 3). Of the 24 patients who survived the first 30 days, 16 patients were in good condition at 1 year of follow-up. No Fig 3. Postoperative three-dimensional reconstruction (A) and computed tomographic scan (B) of porcelain aorta. valve-related late complications occurred. In this period 2 patients were lost and another 6 patients died. In 2 patients the cause of death was unclear, and 4 died as a result of noncardiac reasons. Comment Porcelain aorta remains a challenging problem in cardiac surgery. The best way to treat such patients requiring AVR has not been established yet. The incidence of porcelain aorta varies from 1.2% to 28% with an increasing incidence in older patients and in patients with coronary artery disease combined with aortic valve stenosis [3, 12]. One reason for this great range is the varying definition of the phenomenon porcelain aorta. Imaging methods to preoperatively identify porcelain aorta are computed tomography, chest roentgenography, and also cardiac catheterization. At present none of these methods has been accepted as the gold standard for detecting a heavily calcified and unclampable ascending aorta [1]. The most sensitive technique for detecting ascending aortic atherosclerosis is probably the epiaortic Table 2. Postoperative Outcome Variable n 29 Successful valve implantation (n/%) 29/100 Off-pump treatment (n/%) 25/86.2 Median procedure time (min) 80 (range, ) Fluoroscopy time (min) Contrast dye (ml) Oversizing (mm) Median ventilation time (min) 528 (range, ) 30-day mortality rate (n/%) 5/17.2 Temporary hemodialysis (n/%) 9/31.0 Stroke rate (n/%) 1/3.4 New pacemaker implantation (n/%) 5/17.2 Transvalvular or paravalvular leak 9/31 1 (n/%) Transvalvular or paravalvular leak 1/3.4 1 (n/%) Left ventricular EF Mean aortic gradient (mm Hg) Maximal aortic gradient (mm Hg) EF ejection fraction.

4 1460 KEMPFERT ET AL Ann Thorac Surg MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT 2010;90: Table 3. Causes of Perioperative Deaths Cause n 5 Sudden death 1 Septic multiorgan failure 3 Pulmonary embolism 1 intraoperative echocardiography [13, 14]. Sometimes a heavily calcified aorta is even not recognized until manual palpation can be performed after sternotomy and exposure of the ascending aorta. Patients with a true (completely calcified ascending aorta) porcelain aorta form a unique patient group. Most of these patients will present with numerous additional risk factors like advanced age, coronary artery disease, carotid artery stenosis, history of cerebrovascular accidents, and peripheral arterial disease. Thus this patient population represents a truly high-risk cohort. Unfortunately both The Society of Thoracic Surgeons score and the EuroSCORE fail to represent this increased operative risk for conventional AVR as the calculations are capable only of taking into account the additional risk factors but not the porcelain aorta itself. The best way to deal with porcelain aorta and aortic valve surgery is still unknown. Surgical techniques for AVR in these patients include AVR under deep hypothermic circulatory arrest with or without endarterectomy of the ascending aorta or replacement of the ascending aorta [4, 15, 16]. Endovascular clamping using a balloon [2] is another approach but requires manipulation of the heavily calcified aorta that may result in a certain risk for stroke. Another option to avoid the ascending aorta and cross-clamping is the apicoaortic conduit [17, 18]. The drawback of this technique is that it is only feasible if no additional aortic valve regurgitation is present. In addition, in patients with porcelain aorta significant calcification of the descending aorta is frequent. Thus, anastomosis of the conduit to the descending aorta may turn out to be a challenging task. In our opinion, for relatively young patients, replacement of the calcified aorta under circulatory arrest still might be the most appropriate solution, as this will partly cure the disease. In addition it allows for implantation of a mechanical prosthesis. The apicoaortic conduit is an option for patients with a large aortic annulus diameter when suitable transcatheter prostheses are not available yet. Although different approaches have been described and some of them are quite innovative, all these techniques require CPB as well as manipulations at the calcified aorta to some extent. Thus potential stroke remains a concern. In coronary artery bypass grafting procedures, offpump revascularization using both internal thoracic arteries and sequential Y grafts facilitate a no-touch aortic approach. Hence, this technique basically solved the problem of porcelain aorta in isolated coronary artery bypass grafting patients. With the evolution of transcatheter aortic valve implantation, a new technology to treat high-risk elderly patients similarly avoiding aortic cross-clamping and CPB has become available. Both delivery routes, transfemoral retrograde and transapical antegrade, have been proven to be feasible in such patients. However, in patients presenting with porcelain aorta, peripheral vascular disease may be a frequent condition. Thus the transapical technique may be more appropriate in most of these patients to avoid the often heavily calcified femoral vessels, the abdominal aorta, and most importantly the aortic arch to provide maximal patient safety. Stroke is a devastating complication after cardiac surgery. The presence of a heavily calcified aorta is associated with a significantly increased risk of cerebral embolism during conventional cardiac surgery [12, 19, 20]. In our series only one stroke (3.4%) occurred in a group of high-risk patients with porcelain aorta; 41.4% presented with peripheral vascular disease and 17.2% had had a stroke before the procedure, indicating the high-risk nature of this special patient subgroup. In view of this high-risk profile a stroke rate of 3.4% is acceptable. A 30-day mortality of 17.2% seems to be respectable considering that these patients had several comorbidities and the study group included some of the very early TA-AVI procedures at the beginning of our learning curve. A trend toward lower mortality rates was seen with time, which suggests that there was a learning curve present and that the procedure improved regarding valve positioning, imaging, and management of potential complications. There were 4 deaths in the first half and only 1 death in the second. From our experience in TA-AVI procedures in the presence of porcelain aorta, we believe that too aggressive oversizing should be avoided and that repeat ballooning in case of paravalvular leaks should be performed reluctantly. With this strategy, we have not experienced a case of annular rupture, although that remains one of the major concerns with the TA-AVI technique in heavily calcified aortic roots. Regarding the occurrence of paravalvular leaks we observed only 1 patient (3.4%) with a leak graded higher than mild. In contrast, 9 patients (31%) demonstrated a mild paravalvular leak and 19 patients (65.5%) had trivial or none. These results are comparable to our overall experience and typical for transcatheter aortic valve implantation. The incidence of postoperative renal failure was high in patients with preoperative renal disease (glomerular filtration rate 60 ml/h), although only limited doses of contrast dye were used. The postoperative strategy for patients with acute renal failure was an early dialysis. All dialysis was temporary, and no chronic renal failure occurred. Limitations The study group consisted of all patients who underwent TA-AVI in whom porcelain aorta was identified; the overall number, however, is still limited. The results presented only represent our initial clinical experience

5 Ann Thorac Surg KEMPFERT ET AL 2010;90: MINIMALLY INVASIVE AORTIC VALVE REPLACEMENT with this special patient subgroup. Larger studies and longer follow-up will be required to scientifically prove the superiority of TA-AVI over conventional surgical strategies in patients with porcelain aorta requiring AVR. Conclusions Transapical aortic valve implantation is a promising approach to treat elderly high-risk patients with porcelain aorta requiring AVR and is associated with acceptable outcome and low stroke rates. This truly minimally invasive approach facilitates a no-touch aortic off-pump technique in patients with porcelain aorta requiring AVR. References 1. Jayalath RW, Mangan SH, Golledge J. Aortic calcification. Eur J Vasc Endovasc Surg 2005;30: Ooi A, Iyenger S, Langley SM, et al. Endovascular clamping of porcelain aorta in aortic valve surgery using Foley catheter. Heart Lung Circ 2006;15: Gillinov AM, Lytle BW, Hoang V, et al. The atherosclerotic aorta at aortic valve replacement: surgical strategies and results. J Thorac Cardiovasc Surg 2000;120: Byrne JG, Aranki SF, Cohn LH. Aortic valve operations under deep hypothermic circulatory arrest for the porcelain aorta: no-touch technique. Ann Thorac Surg 1998;65: Loulmet DF, Patel NC, Jennings JM, et al. Less invasive intracardiac surgery performed without aortic clamping. Ann Thorac Surg 2008;85: Cribier A, Eltchaninoff H, Bash A, et al. Percutaneous transcatheter implantation of an aortic valve prosthesis for calcific aortic stenosis: first human case description. Circulation 2002;106: Webb JG, Pasupati S, Humphries K, et al. Percutaneous transarterial aortic valve replacement in selected high-risk patients with aortic stenosis. Circulation 2007;116: Walther T, Falk V, Borger MA, et al. Minimally invasive transapical beating heart aortic valve implantation proof of concept. Eur J Cardiothorac Surg 2007;31: Walther T, Dewey T, Borger MA, et al. 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Management of the calcified aorta: an alternative method of occlusion. Ann Thorac Surg 1983;36: Svensson LG, Sun J, Cruz HA, et al. Endarterectomy for calcified porcelain aorta associated with aortic valve stenosis. Ann Thorac Surg 1996;61: Gammie JS, Krowsoski LS, Brown JM, et al. Aortic valve bypass surgery: midterm clinical outcomes in a high-risk aortic stenosis population. Circulation 2008;118: Hirota M, Oi M, Omoto T, et al. Apico-aortic conduit for aortic stenosis with a porcelain aorta; technical modification for apical outflow. Interact Cardiovasc Thorac Surg 2009;9: Bucerius J, Gummert JF, Borger MA, et al. Stroke after cardiac surgery: a risk factor analysis of 16,184 consecutive adult patients. Ann Thorac Surg 2003;75: Floyd TF, Shah PN, Price CC, et al. Clinically silent cerebral ischemic events after cardiac surgery: their incidence, regional vascular occurrence, and procedural dependence. Ann Thorac Surg 2006;81: INVITED COMMENTARY Management of aortic stenosis in the presence of porcelain aorta remains a formidable challenge in cardiac surgery. Reported options in the past have included endarterectomy and replacement of the aorta under deep hypothermic circulatory arrest, or apicoaortic conduit in the absence of significant aortic insufficiency. However, both are high-risk procedures with the potential for significant mortality and morbidity, especially in elderly patients who already present with other surgical risk factors. Transcatheter aortic valve implantation (AVI) has emerged as an important therapeutic option for patients with severe aortic stenosis not amenable to open surgical intervention. Patients with porcelain aortas would definitively fit into this category. However, because these patients often present with significant aortoiliac and peripheral vascular disease, the transfemoral approach to transcatheter AVI is not an option. Kempfert and coauthors [1] are therefore to be congratulated for presenting their early experience managing this challenging problem with transapical AVI. The group from Leipzig has already published their extensive experience with transapical AVI using the Edwards SAPIEN (Edwards Lifesciences, Irvine, CA) valve [2 4]. The risk profile in this series of 29 patients is significant, with a mean logistic European System for Cardiac Operative Risk Evaluation of 37.7% and Society of Thoracic Surgeons score of 12.8%. The 30-day mortality rate of 17.2% (5 of 29) and stroke rate of 3.5% (1 of 29) compare favorably with those in their previously reported series [2]. The group reported a higher-than-usual pacemaker implantation rate of 17.2%, compared with other published studies on the SAPIEN valve. One may hypothesize that among patients with porcelain aorta, the high degree of calcium embedded in the aortic valve and annulus may cause compression of the membranous septum after valve deployment, causing permanent heart block. In addition, despite a small contrast dose, postoperative renal failure requiring dialysis developed in 31% of patients, suggesting a significant atheroembolic risk from wire manipulation in the porcelain aorta across the arch by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc doi: /j.athoracsur