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Long-Term Results of Neomedia Sinus Valsalva Repair in 489 Patients With Type A Aortic Dissection
Long-Term Results of Neomedia Sinus Valsalva Repair in 489 Patients With Type A Aortic Dissection Bartosz Rylski, MD, Joseph E. Bavaria, MD, Rita K. Milewski, MD, PhD, Prashanth Vallabhajosyula, MD, William Moser, CRNP, Emily Kremens, BS, Alberto Pochettino, MD, Wilson Y. Szeto, MD, and Nimesh D. Desai, MD, PhD Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania, and Heart Center Freiburg University, Freiburg, Germany
Background. Acute type A aortic dissection frequently occurs in patients with normally sized aortic roots. The aim of this investigation was to describe the durability of aortic valve resuspension and root repair with a novel technique of reconstruction in type A dissection. Methods. From 1993 to 2013, among 629 patients operated on for acute type A dissection 489 (62% male, median age 62 years (53; 73) underwent aortic valve resuspension and reinforcement of the sinus of Valsalva with a Teflon felt neomedia. The median follow-up time was 4.1 years (1.3; 6.8) (2075 patient-years). Results. In-hospital mortality was 11% (56/489). Survival was 69% ± 2%, 50% ± 3%, and 36% ± 5% at 5, 10, and 15 years, respectively. Freedom from moderate or severe aortic regurgitation was not influenced by the
aortic regurgitation grade at the initial operation (p [ 0.131). Freedom from proximal aortic reoperation was 96% ± 1%, 92% ± 2%, and 89% ± 4% at 5, 10, and 15 years, respectively. Seventeen patients (3%) required proximal reoperation: 10 for aortic regurgitation, including 3 with concomitant pseudoaneurysm and 2 with root aneurysm; 6 for pseudoaneurysm; and 1 for graft infection. Conclusions. Aortic root neomedia reconstruction and valve resuspension can be successfully performed in the majority of patients with type A dissection. The inhospital mortality is low, and the results are durable.
A
More than 20 years ago, we developed a standardized technique of aortic valve preservation and aortic root reconstruction using Teflon felt neomedia to recreate the media layer, providing a robust root repair [7]. The purpose of the current investigation was to determine the long-term efficacy of the neomedia reconstruction technique.
cute Stanford type A aortic dissection frequently occurs in patients with normal aortic root anatomy. Disruption of the aortic wall architecture involving the sinus segment often results in significant aortic valve insufficiency (AI) [1]. Type A dissection typically begins with a tear in the ascending aorta above the sinotubular junction, with the dissection flap extending into the sinus segment. Most patients who experience acute dissection do not have preexisting aortic valve or sinus segment pathology. Several surgical techniques have been evolved to reconstruct the sinus of Valsalva and restore aortic valve competence [2–4]; however, these methods require using external, internal, or intramural reinforcement with prosthetic, biologic, or autologous materials. Given that several recent studies have reported on the limited durability of some repair techniques, with adverse events arising from dissected tissues left at the root, total root replacement has been advocated as a more definitive repair despite its added complexity [4–6].
Accepted for publication April 1, 2014. Presented at the Fiftieth Annual Meeting of The Society of Thoracic Surgeons, Orlando, FL, Jan 25–29, 2014. Address correspondence to Dr Rylski, Heart Center Freiburg University, Hugstetter Str 55, 79106 Freiburg, Germany; e-mail: bartosz.rylski@ universitaets-herzzentrum.de.
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2014;-:-–-) Ó 2014 by The Society of Thoracic Surgeons
Patients and Methods Study Population and Definitions Between January 1993 and May 2013, among 629 patients operated on for acute Stanford type A aortic dissection at the Hospital of the University of Pennsylvania, 489 patients (78%) underwent ascending aortic replacement with aortic valve resuspension and sinus of Valsalva preservation with neomedia reconstruction. These patients constitute the study population. The rate of aortic root repairs and the total number of patients with type A dissection operated on per year throughout the study period are given in Figure 1. Acute aortic dissection was defined as a dissection operated on no later than 14 days after the onset of symptoms. The ascending aortic diameter was assessed before operation by transesophageal echocardiography and was available in 338 patients (69%). Malperfusion syndromes were diagnosed by clinical examination and 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2014.04.050
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Fig 1. Rate of aortic root repairs and total number of patients with acute type A aortic dissection operated on per year throughout the study period.
confirmed by computed tomographic angiography. Perioperative data were derived from a prospectively collected database. The institutional review committee approved this retrospective study, and the need for informed consent was waived.
Surgical Approach In all patients, previously described standardized integrated surgical management was applied [7]. Briefly, this approach included fast-track [7, 8] direct admission to the operating room and immediate operative repair, including replacement of the entire ascending aorta with distal anastomosis performed in an open fashion. The ascending aorta true lumen, the axillary, or femoral artery cannulation was used for arterial inflow. Cerebral protection was achieved by retrograde cerebral perfusion. In patients requiring more extensive arch reconstruction necessitating more than 40 minutes of circulatory arrest, we used selective bilateral antegrade cerebral perfusion. Myocardial protection was achieved with a combination of intermittent antegrade and retrograde cold blood cardioplegia. The aortic root repair included resuspension of the aortic valve with three pledged 4-0 polypropylene mattress sutures at the top of the three commissures and Teflon felt neomedia placed between the dissected layers. The Teflon felt was fashioned to reconstruct the entire dissected portion, typically filling the entire noncoronary sinus and the lateral portion of the right sinus, with care taken not to impinge on the origin of the right coronary artery (Fig 2). In case of extension of the dissection process down to the level of the coronary ostia, we beveled the Teflon felt, cutting out its central portion to create a free space for the coronary artery so that the felt filled the area on both sites of the coronary ostium but did not affect the origin of the coronary artery [7]. The Teflon felt repair was secured with a small amount of BioGlue (CroyLife Inc, Kennesaw, GA) between the dissected layers and sutured in place with a running 5-0 polypropylene suture. The proximal anastomosis with a Dacron graft was then sewn circumferentially to either the reconstructed or the undissected aorta. Typically, the Dacron graft size was chosen to be within
10% of the annular dimension as measured by echocardiography. In cases of root aneurysm (>4.5 cm), aortic valve structural leaflet pathology, intimal entry tear extending into the sinus segment, and known connective tissue disorders, the aortic root was replaced. A functional normal bicuspid aortic valve (BAV) was not a contraindication for neomedia repair. Patients who underwent aortic root replacement were excluded from the present analysis. Distal replacement of the aortic arch was performed with the patient in hypothermic circulatory arrest conditions by reinforcement of the residual arch tissue with Teflon felt neomedia.
Patient Follow-Up Surveillance follow-up data were obtained by review of medical records; by contact with the general practitioners, the patients, and their family members; or by the Social Security Death Index. Complete follow-up was available in 423 of 433 hospital survivors (98%). The patients were followed up for a total of 2075 patient-years, with a median follow-up time among survivors of 4.1 years (1.3; 6.8). Eighteen percent were followed up for 10 or more years. The durability of root repair was assessed by follow-up transthoracic echocardiography and computed tomographic angiography 6 and 12 months postoperatively, and annually thereafter. The median follow-up time for transthoracic echocardiography was 2.9 years (1.1; 4.6). Complete echocardiographic follow-up among survivors was achieved in 388 of 433 patients (90%).
Statistical Analysis Continuous data are presented as median (first quartile; third quartile); categoric variables are given as counts and percentages. For comparison of continuous variables, Student’s t test was applied when normal distribution was present as determined by the Kolmogorov-Smirnov test. For not normally distributed variables, the MannWhitney rank sum test was used. Categoric variables were compared with the c2 test. For small group sizes (n <5), Fisher’s exact test was used. Survival, freedom from reoperation, and freedom from moderate or severe aortic valve regurgitation were analyzed by the KaplanMeier method and log-rank calculations. For the final
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Fig 2. After resuspension of the aortic valve, (A) the Teflon felt fashioned according to the dissected aortic root portion (B) was placed between the dissected layers, (C) typically filling the entire noncoronary sinus and the lateral portion of the right sinus. (D) The Teflon felt was sutured in place with a running 5-0 polypropylene suture.
multivariable logistic regression model on predictors of in-hospital mortality, we evaluated age over 80 years, female gender, diabetes mellitus, Marfan syndrome (MFS), previous coronary artery bypass grafting, cardiogenic shock, malperfusion of one or more organs, total arch replacement, and cardiopulmonary bypass time. Variables with p < 0.1 in a univariate analysis were included in the multivariable logistic regression model.
three grades in 51 (10%), by two grades in 93 (19%), and by one grade in 141 (29%). Two patients had postoperative moderate AI, and 1 of them underwent concomitant aortic valve replacement. One more patient underwent conversion to aortic root replacement because of bleeding at the aortic root. Surgical details on distal aortic repair and concomitant procedures are given in Table 2.
Results
Morbidity, In-Hospital Mortality, and Survival
Demographics and Clinical Presentation
Thirty-two patients (7%) required repeated exploration of the chest for bleeding. New postoperative strokes occurred in 26 patients (5%) and transient ischemic attack in 35 (7%). Sixty-eight patients (14%) experienced acute renal failure, and 36 (7%) required temporary dialysis. The in-hospital mortality was 11% (56 of 489 patients). The primary reason for in-hospital death was heart failure in 14 patients (25%), multisystem organ failure in 28 (50%), exsanguination in 6 (11%), and neurologic events in 8 (14%). The overall survival was 83 2%, 69 2%, 50 3%, and 36 5% at 1, 5, 10, and 15 years, respectively (Fig 3).
The average age was 62 years (53; 73). In 332 patients (68%), the ages ranged between 50 and 80 years, and 56 patients (11%) were older than 80 years. Most of the patients were men (62%). BAV was observed in 7 patients (1%) and MFS with diagnosis made after operation in 11 patients (2%). Twenty-eight patients (6%) had undergone previous cardiac operations. One hundred twenty patients (25%) experienced cardiac tamponade, and 100 patients (20%) were operated on in cardiogenic shock. In 347 (71%) of all patients, aortic dissection extended beyond the aortic arch. Malperfusion syndromes were evident in 156 patients (32%) (Table 1).
In-Hospital Mortality Risk Factors Aortic Valve Repairs Preoperative moderate to severe aortic valve insufficiency was present in 147 patients (30%). All patients underwent aortic root repair with Teflon felt neomedia and aortic valve resuspension, except for those with previous aortic valve replacement (n ¼ 6). AI was reduced by four grades (from severe to no insufficiency) in 19 patients (4%), by
In the multivariable logistic regression analysis, independent predictors of in-hospital mortality were female gender (OR: 1.95; p ¼ 0.049), cardiogenic shock (OR: 3.89; p < 0.001), and malperfusion syndrome of one or more organs (OR: 6.83; p < 0.001) (Table 3). The in-hospital mortality did not differ significantly between women and men (14 vs 10%, p ¼ 0.246).
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Table 1. Demographics and Clinical Presentation Characteristic Age (years) Over 80 years old Under 65 years old Male gender Clinical presentation Current smoker Hypertension Diabetes mellitus Previous cardiac operation Previous CABG Previous AVR COPD Renal failure Coronary artery disease Prior Stroke Prior TIA MFS BAV Extent of dissection DeBakey I DeBakey II Ascending aortic diameter (cm) AI (mod-sev) Cardiac tamponade Cardiogenic shock Malperfusion One or more organs Coronary Cerebral Iliofemoral Gastrointestinal Spinal
No. (%) (n ¼ 489) 62 56 275 301
(53; 73) (11) (56) (62)
13 408 47 28 19 6 52 38 79 40 29 11 7
(3) (83) (10) (6) (4) (1) (11) (8) (16) (8) (6) (2) (1)
347 142 4.8 147 120 100
(71) (29) (4.3; 5.5) (30) (25) (20)
156 21 48 66 36 6
(32) (4) (10) (14) (7) (1)
Table 2. Surgical Procedures for Type A Aortic Dissection: Details and Outcome Variable Distal repair Hemiarch replacement Total arch replacement Thoracic aortic stent grafting Other procedures CABG Mitral valve repair CPB time (minutes) CX time (minutes) HCA time (minutes) In-hospital mortality
No. (%) (n ¼ 489) 468 (96) 21 (4) 60 (12) 7 3 205 135 35 56
(1) (1) (182; 239) (114; 162) (28; 47) (11)
CABG ¼ coronary artery bypass grafting; CPB ¼ cardiopulmonary bypass; CX ¼ cross-clamp; HCA ¼ hypothermic circulatory arrest. Categoric values are n (%), continuous values are median (first interquartile; third interquartile).
Aortic Root Reoperation Freedom from proximal reoperation was 100% 0%, 96% 1%, 92% 2%, and 89% 4% at 1, 5, 10, and 15 years, respectively (Fig 4). Seventeen patients (3%) (including 1 with MFS) at a median of 3.2 years (2.1; 6.5) postoperatively required proximal reoperations: 6 for pseudoaneurysm, 5 for severe aortic regurgitation (with concomitant mild, moderate, and severe calcification in 1 patient each), 3 for both aortic regurgitation and pseudoaneurysm, 2 for aortic regurgitation and root aneurysm, and 1 for graft infection. Four patients did
AI ¼ aortic valve insufficiency; AVR ¼ aortic valve replacement; BAV ¼ bicuspid aortic valve; CABG ¼ coronary artery bypass grafting; COPD ¼ chronic obstructive pulmonary disease; MFS ¼ Marfan syndrome; mod ¼ moderate; sev ¼ severe; TAV ¼ tricuspid aortic valve; TIA ¼ transient ischemic attack. Categoric values are n (%); continuous values are median (first interquartile; third interquartile).
Durability of Aortic Valve Resuspension Freedom from moderate or severe aortic valve regurgitation at follow-up did not differ between patients with initial no or mild valve insufficiency (99% 0%, 97% 1%, and 88% 3% at 1, 5, and 10 years, respectively) and those with initial moderate or severe valve insufficiency (98% 2%, 96% 2%, and 76% 9% at 1, 5, and 10 years, respectively) (log-rank, p ¼ 0.131), with 42 initial no or mild and 13 initial moderate or severe valve insufficiency patients remaining at risk at 10 years. Overall, 23 patients (5%) experienced moderate and 10 (2%) severe AI, and 3 patients (1%) experienced moderate and 2 (1%) severe aortic valve stenosis during the follow-up period.
Fig 3. Kaplan-Meier analysis of overall survival in patients who underwent aortic root repair for acute type A aortic dissection (number of events at 10 years: 165).
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Table 3. Multivariable Analysis of In-Hospital Mortality Risk Factors for Aortic Root Repair in Acute Type A Dissection Variable
OR
95% CI
p Value
Age >80 years Female gender Previous CABG Cardiopulmonary shock One or more organs with malperfusion Total arch replacement Cardiopulmonary bypass time
2.30 1.95 3.16 3.89 6.83
0.88-6.05 1.00-3.79 0.83-12.10 1.95-7.78 3.37-13.84
0.091 0.049 0.093 <0.001 <0.001
3.57 1.01
0.98-12.97 1.00-1.02
0.053 0.021
CABG ¼ coronary artery bypass grafting; val; OR ¼ odds ratio.
CI ¼ confidence inter-
not survive the secondary operation or the early perioperative period: 1 died of bowel ischemia 1 week after secondary aortic root replacement; 1 MFS patient died of ruptured descending thoracic aorta 10 days after uncomplicated aortic root (for pseudoaneurysm) and arch replacement; 1 patient was an intravenous drug abuser and died intraoperatively after attempted repair of proximal pseudoaneurysm accompanied by graft infection, aorto–right atrial fistula, and right ventricular failure; and 1 patient died of multisystem organ failure 4 days after aortic valve replacement and mitral valve repair for severe aortic valve stenosis and severe mitral valve insufficiency. Additionally, among 11 MFS patients, 1 more patient experienced severe AI 6 years after the primary operation but died of ruptured abdominal aneurysm before the scheduled redo operation, cumulating in two of 11 proximal aortic adverse events rate in MFS patients. None of the 7 BAV patients required proximal reoperation. One of them experienced moderate AI 18 years
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after the operation (at 83 years of age) and is treated medically.
Comment Operative Mortality of Standardized Approach to Type A Dissection The perioperative mortality rates in patients with acute type A dissection who undergo ascending aortic replacement with aortic root preservation have improved considerably over time and with increased operator experience, but they still differ widely (8% to 34%) [3, 5, 9]. Despite the high proportion of patients in cardiogenic shock (20%) and patients with malperfusion syndrome (32%), the 11% rate of in-hospital mortality in our series of 489 consecutive patients is within the lower end of the range in the published series. High-volume centers typically show improved results owing to their large practice and greater expertise. A major aspect of improving the outcomes in patients with type A dissection involves the use of a standardized perioperative approach. Our practice is to admit the patient directly to the operating room and to perform immediate operative repair, regardless of the patient’s condition and without any additional preoperative workup such as cardiac catheterization or cerebral imaging. The ascending aorta is replaced in all patients, aortic valve resuspension and sinus segment repair are performed whenever it is rational as previously described [7, 8], and all patients undergo routine open aortic arch replacement under hypothermic circulatory arrest. When we introduced our algorithm 20 years ago, we operated on fewer than 10 patients a year, and this standardized approach for infrequently performed procedures helped us to treat patients quickly and effectively. Now, on average 50 to 60 patients per year with acute type A dissection are operated on, and in 80% of them the aortic root is preserved.
Durability of Aortic Root Repair
Fig 4. Kaplan-Meier analysis of freedom from proximal reoperation (number of events at 10 years: 16).
The advantages of sinus segment and native aortic valve preservation are avoidance of coronary artery manipulation and its related potential adverse events, reduction of cross-clamp and cardiopulmonary bypass times, elimination of the risk of prosthetic valve endocarditis, and avoidance of a permanent need for anticoagulation in mechanical valve replacement. Anticoagulation therapy not only decreases the quality of life but also substantially inhibits aortic false lumen thrombosis. Patency of the false lumen in the descending aorta has been shown to be a strong independent risk factor for dissection-related late adverse events and death [10, 11]. In the current series, aortic dissection extended beyond the aortic arch in 71% of patients. More than half of the patients (56%) were younger than 65 years, and most of them might have required mechanical valve prostheses if they had undergone root replacement. Another option in such patients may be aortic root reimplantation, but this requires significantly more cardiac ischemic time, and the outcomes may be highly operator dependent.
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There is no doubt that the advantages of root preservation should be balanced against the risk of proximal reoperation in follow-up. Freedom from aortic root reoperation in patients who have undergone prior aortic repair for type A dissection with root retention has been reported to be between 69% and 95% at 10 years [3, 6, 12]. However, the limitation of those reports is the application of different aortic root repair techniques, which are strongly influenced by surgeons’ preferences. In the present series of standardized neomedia root repair, the freedom from aortic root reoperation at 10 years was 92%. Most root reinterventions were indicated by pseudoaneurysm or aortic valve regurgitation and only two of them by true aortic root aneurysm. We are unaware of any histologic studies that present the natural history of dissected sinus segment reconstructed with intramural Teflon felt, but the very low incidence of true root aneurysm after the neomedia repair supports its efficacy. Teflon felt has a profibrotic effect, frequently observed on reoperation in patients with Teflon used, for example, outside the aorta to reinforce the suture line. It is conceivable that placing the Teflon felt between dissected layers stabilizes the aortic root and prevents the development of aortic root aneurysm because of its profibrotic effect. Furthermore, the presence of Teflon felt in the media layer is very effective at preventing tears and bleeding from the needle holes in the dissected tissue. According to our experience with secondary root procedures performed in type A dissection patients operated on primarily at other institutions, a substantial number have secondary true root aneurysms, and in most of them the dissected sinus segment was not reconstructed with an intramural felt. The retrospective design of our study does not allow making a definitive statement; however, the neomedia concept applied in a large population with type A dissection showed very stable root reconstruction results. There were very few instances of reoperation for recurrent aortic insufficiency even though 30% of patients present primarily moderate to severe aortic insufficiency, which is indicative of the efficacy of this root repair technique to restore valvular geometry. In this series, 5 patients underwent proximal, secondary operations for severe AI. Recently, transcatheter aortic valve implantation, applying currently available devices, has been shown to be feasible in 43 patients with pure native aortic valve regurgitation [13]. Transcatheter aortic valve implantation is still only anecdotally used for AI without valve stenosis, but in the future it might be a treatment option for high-risk patients with aortic regurgitation or stenosis after operations for type A dissection.
Outcome in Patients With Genetically Triggered Type A Dissection In our cohort, 11 MFS patients underwent aortic valve resuspension and root repair in the emergency setting of acute type A dissection, inasmuch as their MFS diagnoses were not known at the time of operation, and their aortic roots were not dilated. One of them underwent a proximal secondary operation for pseudoaneurysm, and in 1 more patient secondary aortic valve replacement was
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indicated; however, this patient died of ruptured abdominal aorta before admission for a secondary operation. Reinforcing the sinus segment with a Teflon felt placed inside the aortic wall may prevent root dilatation in MFS patients also. However, our data do not allow us to recommend neomedia root repair in patients with MFS because the patient number is insufficient. Our policy in patients with diagnosed MFS and acute type A aortic dissection is to replace the aortic root or repair it by the means of the David reimplantation technique [14]. The Mayo Clinic group has recently demonstrated that nonreplaced sinuses of Valsalva in BAV disease after aortic valve replacement did not dilate at late follow-up [15]. In our series of neomedia root repair and aortic valve resuspension, none of the 7 BAV patients experienced aortic root aneurysm in the follow-up period, and 1 of them experienced moderate AI 18 years later and is currently being treated medically. However, more patients and longer follow-up times are required for the determination of long-term bicuspid valve and root durability. In conclusion, aortic root neomedia reconstruction and aortic valve resuspension can be successfully performed in the vast majority of patients with acute type A aortic dissection and are associated with low in-hospital mortality and low root reoperation rate in the long run. Therefore, liberal use of a composite graft replacement for type A dissection regardless of the root and valve predissection anatomy and function is not justified. We recommend that aortic root repair applying the Teflon felt neomedia concept and aortic valve resuspension should be considered in any case of acute type A dissection except for patients with aortic root aneurysm (>4.5 cm), aortic valve leaflet pathology or intimal tear extending into the sinus segment, and known connective tissue disorders.
References 1. Movsowitz HD, Levine RA, Hilgenberg AD, Isselbacher EM. Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in acute type A aortic dissection: implications for aortic valve repair. J Am Coll Cardiol 2000;36:884–90. 2. Weinschelbaum EE, Schamun C, Caramutti V, Tacchi H, Cors J, Favaloro RG. Surgical treatment of acute type A dissecting aneurysm, with preservation of the native aortic valve and use of biologic glue. J Thorac Cardiovasc Surg 1992;103:369–74. 3. Mazzucotelli JP, Deleuze PH, Baufreton C, et al. Preservation of the aortic valve in acute aortic dissection: long-term echocardiographic assessment and clinical outcome. Ann Thorac Surg 1993;55:1513–7. 4. Halstead JC, Spielvogel D, Meier DM, et al. Composite aortic root replacement in acute type A dissection: time to rethink the indications? Eur J Cardiothorac Surg 2005;27:626–32. 5. Casselman FP, Tan ES, Vermeulen FE, Kelder JC, Morshuis WJ, Schepens MA. Durability of aortic valve preservation and root reconstruction in acute type A aortic dissection. Ann Thorac Surg 2000;70:1227–33. 6. Rylski B, Beyersdorf F, Blanke P, et al. Supracoronary ascending aortic replacement in patients with acute aortic dissection type A: what happens to the aortic root in the long run? J Thorac Cardiovasc Surg 2013;146:285–90. 7. Bavaria JE, Pochettino A, Brinster DR, et al. New paradigms and improved results for the surgical treatment of acute type A dissection. Ann Surg 2001;234:336–42.
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8. Geirsson A, Bavaria JE, Swarr D, et al. Fate of the residual distal and proximal aorta after acute type A dissection repair using a contemporary surgical reconstruction algorithm. Ann Thorac Surg 2007;84:1955–64. 9. Dell’aquila AM, Concistre G, Gallo A, et al. Fate of the preserved aortic root after treatment of acute type A aortic dissection: 23-year follow-up. J Thorac Cardiovasc Surg 2013;146:1456–60. 10. Akutsu K, Nejima J, Kiuchi K, et al. Effects of the patent false lumen on the long-term outcome of type B acute aortic dissection. Eur J Cardiothorac Surg 2004;26:359–66. 11. Park KH, Lim C, Choi JH, et al. Midterm change of descending aortic false lumen after repair of acute type I dissection. Ann Thorac Surg 2009;87:103–8.
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12. Von Segesser LK, Lorenzetti E, Lachat M, et al. Aortic valve preservation in acute type A dissection: is it sound? J Thorac Cardiovasc Surg 1996;111:381–91. 13. Roy DA, Schaefer U, Guetta V, et al. Transcatheter aortic valve implantation for pure severe native aortic valve regurgitation. J Am Coll Cardiol 2013;61:1577–84. 14. Rylski B, Bavaria JE, Beyersdorf F, et al. Type A aortic dissection in Marfan syndrome: extent of initial surgery determines long-term outcome. Circulation 2014;129: 1381–6. 15. Park CB, Greason KL, Suri RM, Michelena HI, Schaff HV, Sundt TM 3rd. Fate of nonreplaced sinuses of Valsalva in bicuspid aortic valve disease. J Thorac Cardiovasc Surg 2011;142:278–84.
DISCUSSION DR RICHARD J. SHEMIN (Los Angeles, CA): This is a very nice case presentation. In the evolution of this technique, did you ever use BioGlue and then abandon it? Also, what is the thickness of the felt used in the media? Is it the standard-thickness felt that we often use for outer reconstruction and buttressing, or is it a special-order, thinner felt to fit nicely in the media? DR DESAI: I’ll answer your second question first. The felt is the regular felt. It’s a thick felt. There are some subtleties in putting the felt in, and particularly not to oversize it too much because that thick felt is pretty stiff, but a standard beveled piece works very well. In terms of BioGlue, number one, our practice has changed over time and, number two, varies a little bit between the different surgeons. We traditionally have reported this technique to use BioGlue to help glue the felt in place and then oversew it. I think that we have limited the amount of glue we use significantly. Occasionally we use a couple of drops here or there, but not in any major way. DR SHEMIN: So would you recommend that glue alone is insufficient, that the felt is the better technique? DR DESAI: Felt is a better technique. DR SHEMIN: I have a follow-up question. Obviously you described aortic roots that are relatively small. Has this made you rethink the indications for elective procedures? When people are referred with a root between, say, 4.5 and 4.8, where it’s clearly larger than the descending aorta by one and a half or close to two times, have you considered elective procedures on these patients instead of waiting for a dissection in an otherwise clinically relatively normal root? DR DESAI: That is a good point. We have looked at our data. We are presenting this at the AATS as well: the issue of size. In fact, a multinational study that we did with Bartosz Rylski, who is one of our fellows who put this together with Martin and a whole group of centers in the United States that is coming out in JACC shortly, looked at this concept of how big the aorta is when it dissects and how much it grows after it dissects. In our own experience, 80% to 90% of patients when they dissect probably had an aortic dimension that was less than 4.5 cm. We don’t really understand who dissects. There is a genetic component, clearly. Size has something to do with it, and certainly when you are in the 6-plus range or 5.5 range, it is an important indicator. We don’t know what the denominator is for the 4-cm aortas as to how many people have 4-cm aortas and what proportion of those dissect, but there is probably some genetic or biochemical
marker that we can use to identify them. Size is not the only criterion. DR SHEMIN: So what is your lower level of elective procedures if you do look at size criteria? DR DESAI: I think we generally stick with the size criteria by the guidelines: 5.5 for a standard atherosclerotic aneurysm, 5 to 5.5 for a bicuspid, and 4 to 4.5 for someone with a clear genetic syndrome, like Loeys-Dietz or Marfan. DR TOMAS D. MARTIN (Gainesville, FL): I would first like to compliment you and the University of Pennsylvania team for your results, and particularly the system you have set up for care of these patients. My first question really had to do with glue, but I think you have probably answered that. We still use a combination of felt inside and outside and glue to create the neomedia. You might comment again on why you think your technique might be better than that. I really wanted you or Dr Bavaria to comment particularly on your use of central cannulation. In today’s world, everybody talks about how you have to cannulate the axillary artery. We do not routinely cannulate the axillary artery. You use central cannulation most frequently over a wire, and many people don’t even understand that. If you wouldn’t mind commenting on that and why you think that might be better, I would appreciate it. DR DESAI: We adopted that technique probably about 7 or 8 years ago. The key thing is to look at the preoperative imaging to understand where the true lumen is. Again, we are going to be presenting our whole series of this at the AATS in April. There are two approaches to this. Number one is to either put the needle through the false lumen, through the flap, and into the true, or to try to cannulate the true directly. In our experience, most of the time we do the former; we go through the false lumen with the needle, advance it slowly until you feel it hit the flap, and then push it a little, and the blood stops coming through it, an 18-gauge needle, and then you push it a little bit farther, and then you have nice pulsatile bright red blood. We pass the wire down. We have a TEE probe in the descending aorta, and we look for the wire in the true lumen in the descending aorta. In certain situations we will also use epiaortic ultrasound to help identify which lumen is where. Then we just serially dilate and then put in a standard long femoral cannula, an 18F femoral cannula. DR ROBERT B. LEE (Paducah, KY): I have two questions. It was a great presentation, clear, concise, and reproducible. When you
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put your neointima in, it looks like the only suture line is above at the aortic level, at the anastomosis level. Are you putting any sutures at the bottom of the implant? DR DESAI: No, definitely not. DR LEE: And the second question is simple too. Have you ever considered using bovine pericardium as opposed to felt? DR DESAI: We think that the felt has a lot of beneficial effects in terms of scarring in that noncoronary sinus so it doesn’t dilate later, but it is very thrombogenic on the inside, and even if there was a little residual flow through a needle hole or something like that, it tends to thrombose it. We do have a follow-up study looking at some of the echocardiography and computed tomography parameters of these roots, and what we
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have seen is that the aortic root actually shrinks down around this felt. DR JOHN W. FEHRENBACHER (Indianapolis, IN): Have you ever seen a pseudoaneurysm in the noncoronary sinus in your postoperative follow-up? DR DESAI: No, not in that series, none. DR FEHRENBACHER: We have seen pseudoaneurysms when glue alone was used for dissections involving the sinuses, so we always use felt sandwich in addition to glue. DR DESAI: Yes, in patients who have tears within the root below the sinotubular junction, we have seen it.
Background. Acute type A aortic dissection frequently occurs in patients with normally sized aortic roots. The aim of this investigation was to describe the durability of aortic valve resuspension and root repair with a novel technique of reconstruction in type A dissection. Methods. From 1993 to 2013, among 629 patients operated on for acute type A dissection 489 (62% male, median age 62 years (53; 73) underwent aortic valve resuspension and reinforcement of the sinus of Valsalva with a Teflon felt neomedia. The median follow-up time was 4.1 years (1.3; 6.8) (2075 patient-years). Results. In-hospital mortality was 11% (56/489). Survival was 69% ± 2%, 50% ± 3%, and 36% ± 5% at 5, 10, and 15 years, respectively. Freedom from moderate or severe aortic regurgitation was not influenced by the
aortic regurgitation grade at the initial operation (p [ 0.131). Freedom from proximal aortic reoperation was 96% ± 1%, 92% ± 2%, and 89% ± 4% at 5, 10, and 15 years, respectively. Seventeen patients (3%) required proximal reoperation: 10 for aortic regurgitation, including 3 with concomitant pseudoaneurysm and 2 with root aneurysm; 6 for pseudoaneurysm; and 1 for graft infection. Conclusions. Aortic root neomedia reconstruction and valve resuspension can be successfully performed in the majority of patients with type A dissection. The inhospital mortality is low, and the results are durable.
A
More than 20 years ago, we developed a standardized technique of aortic valve preservation and aortic root reconstruction using Teflon felt neomedia to recreate the media layer, providing a robust root repair [7]. The purpose of the current investigation was to determine the long-term efficacy of the neomedia reconstruction technique.
cute Stanford type A aortic dissection frequently occurs in patients with normal aortic root anatomy. Disruption of the aortic wall architecture involving the sinus segment often results in significant aortic valve insufficiency (AI) [1]. Type A dissection typically begins with a tear in the ascending aorta above the sinotubular junction, with the dissection flap extending into the sinus segment. Most patients who experience acute dissection do not have preexisting aortic valve or sinus segment pathology. Several surgical techniques have been evolved to reconstruct the sinus of Valsalva and restore aortic valve competence [2–4]; however, these methods require using external, internal, or intramural reinforcement with prosthetic, biologic, or autologous materials. Given that several recent studies have reported on the limited durability of some repair techniques, with adverse events arising from dissected tissues left at the root, total root replacement has been advocated as a more definitive repair despite its added complexity [4–6].
Accepted for publication April 1, 2014. Presented at the Fiftieth Annual Meeting of The Society of Thoracic Surgeons, Orlando, FL, Jan 25–29, 2014. Address correspondence to Dr Rylski, Heart Center Freiburg University, Hugstetter Str 55, 79106 Freiburg, Germany; e-mail: bartosz.rylski@ universitaets-herzzentrum.de.
Ó 2014 by The Society of Thoracic Surgeons Published by Elsevier Inc
(Ann Thorac Surg 2014;-:-–-) Ó 2014 by The Society of Thoracic Surgeons
Patients and Methods Study Population and Definitions Between January 1993 and May 2013, among 629 patients operated on for acute Stanford type A aortic dissection at the Hospital of the University of Pennsylvania, 489 patients (78%) underwent ascending aortic replacement with aortic valve resuspension and sinus of Valsalva preservation with neomedia reconstruction. These patients constitute the study population. The rate of aortic root repairs and the total number of patients with type A dissection operated on per year throughout the study period are given in Figure 1. Acute aortic dissection was defined as a dissection operated on no later than 14 days after the onset of symptoms. The ascending aortic diameter was assessed before operation by transesophageal echocardiography and was available in 338 patients (69%). Malperfusion syndromes were diagnosed by clinical examination and 0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2014.04.050
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Fig 1. Rate of aortic root repairs and total number of patients with acute type A aortic dissection operated on per year throughout the study period.
confirmed by computed tomographic angiography. Perioperative data were derived from a prospectively collected database. The institutional review committee approved this retrospective study, and the need for informed consent was waived.
Surgical Approach In all patients, previously described standardized integrated surgical management was applied [7]. Briefly, this approach included fast-track [7, 8] direct admission to the operating room and immediate operative repair, including replacement of the entire ascending aorta with distal anastomosis performed in an open fashion. The ascending aorta true lumen, the axillary, or femoral artery cannulation was used for arterial inflow. Cerebral protection was achieved by retrograde cerebral perfusion. In patients requiring more extensive arch reconstruction necessitating more than 40 minutes of circulatory arrest, we used selective bilateral antegrade cerebral perfusion. Myocardial protection was achieved with a combination of intermittent antegrade and retrograde cold blood cardioplegia. The aortic root repair included resuspension of the aortic valve with three pledged 4-0 polypropylene mattress sutures at the top of the three commissures and Teflon felt neomedia placed between the dissected layers. The Teflon felt was fashioned to reconstruct the entire dissected portion, typically filling the entire noncoronary sinus and the lateral portion of the right sinus, with care taken not to impinge on the origin of the right coronary artery (Fig 2). In case of extension of the dissection process down to the level of the coronary ostia, we beveled the Teflon felt, cutting out its central portion to create a free space for the coronary artery so that the felt filled the area on both sites of the coronary ostium but did not affect the origin of the coronary artery [7]. The Teflon felt repair was secured with a small amount of BioGlue (CroyLife Inc, Kennesaw, GA) between the dissected layers and sutured in place with a running 5-0 polypropylene suture. The proximal anastomosis with a Dacron graft was then sewn circumferentially to either the reconstructed or the undissected aorta. Typically, the Dacron graft size was chosen to be within
10% of the annular dimension as measured by echocardiography. In cases of root aneurysm (>4.5 cm), aortic valve structural leaflet pathology, intimal entry tear extending into the sinus segment, and known connective tissue disorders, the aortic root was replaced. A functional normal bicuspid aortic valve (BAV) was not a contraindication for neomedia repair. Patients who underwent aortic root replacement were excluded from the present analysis. Distal replacement of the aortic arch was performed with the patient in hypothermic circulatory arrest conditions by reinforcement of the residual arch tissue with Teflon felt neomedia.
Patient Follow-Up Surveillance follow-up data were obtained by review of medical records; by contact with the general practitioners, the patients, and their family members; or by the Social Security Death Index. Complete follow-up was available in 423 of 433 hospital survivors (98%). The patients were followed up for a total of 2075 patient-years, with a median follow-up time among survivors of 4.1 years (1.3; 6.8). Eighteen percent were followed up for 10 or more years. The durability of root repair was assessed by follow-up transthoracic echocardiography and computed tomographic angiography 6 and 12 months postoperatively, and annually thereafter. The median follow-up time for transthoracic echocardiography was 2.9 years (1.1; 4.6). Complete echocardiographic follow-up among survivors was achieved in 388 of 433 patients (90%).
Statistical Analysis Continuous data are presented as median (first quartile; third quartile); categoric variables are given as counts and percentages. For comparison of continuous variables, Student’s t test was applied when normal distribution was present as determined by the Kolmogorov-Smirnov test. For not normally distributed variables, the MannWhitney rank sum test was used. Categoric variables were compared with the c2 test. For small group sizes (n <5), Fisher’s exact test was used. Survival, freedom from reoperation, and freedom from moderate or severe aortic valve regurgitation were analyzed by the KaplanMeier method and log-rank calculations. For the final
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Fig 2. After resuspension of the aortic valve, (A) the Teflon felt fashioned according to the dissected aortic root portion (B) was placed between the dissected layers, (C) typically filling the entire noncoronary sinus and the lateral portion of the right sinus. (D) The Teflon felt was sutured in place with a running 5-0 polypropylene suture.
multivariable logistic regression model on predictors of in-hospital mortality, we evaluated age over 80 years, female gender, diabetes mellitus, Marfan syndrome (MFS), previous coronary artery bypass grafting, cardiogenic shock, malperfusion of one or more organs, total arch replacement, and cardiopulmonary bypass time. Variables with p < 0.1 in a univariate analysis were included in the multivariable logistic regression model.
three grades in 51 (10%), by two grades in 93 (19%), and by one grade in 141 (29%). Two patients had postoperative moderate AI, and 1 of them underwent concomitant aortic valve replacement. One more patient underwent conversion to aortic root replacement because of bleeding at the aortic root. Surgical details on distal aortic repair and concomitant procedures are given in Table 2.
Results
Morbidity, In-Hospital Mortality, and Survival
Demographics and Clinical Presentation
Thirty-two patients (7%) required repeated exploration of the chest for bleeding. New postoperative strokes occurred in 26 patients (5%) and transient ischemic attack in 35 (7%). Sixty-eight patients (14%) experienced acute renal failure, and 36 (7%) required temporary dialysis. The in-hospital mortality was 11% (56 of 489 patients). The primary reason for in-hospital death was heart failure in 14 patients (25%), multisystem organ failure in 28 (50%), exsanguination in 6 (11%), and neurologic events in 8 (14%). The overall survival was 83 2%, 69 2%, 50 3%, and 36 5% at 1, 5, 10, and 15 years, respectively (Fig 3).
The average age was 62 years (53; 73). In 332 patients (68%), the ages ranged between 50 and 80 years, and 56 patients (11%) were older than 80 years. Most of the patients were men (62%). BAV was observed in 7 patients (1%) and MFS with diagnosis made after operation in 11 patients (2%). Twenty-eight patients (6%) had undergone previous cardiac operations. One hundred twenty patients (25%) experienced cardiac tamponade, and 100 patients (20%) were operated on in cardiogenic shock. In 347 (71%) of all patients, aortic dissection extended beyond the aortic arch. Malperfusion syndromes were evident in 156 patients (32%) (Table 1).
In-Hospital Mortality Risk Factors Aortic Valve Repairs Preoperative moderate to severe aortic valve insufficiency was present in 147 patients (30%). All patients underwent aortic root repair with Teflon felt neomedia and aortic valve resuspension, except for those with previous aortic valve replacement (n ¼ 6). AI was reduced by four grades (from severe to no insufficiency) in 19 patients (4%), by
In the multivariable logistic regression analysis, independent predictors of in-hospital mortality were female gender (OR: 1.95; p ¼ 0.049), cardiogenic shock (OR: 3.89; p < 0.001), and malperfusion syndrome of one or more organs (OR: 6.83; p < 0.001) (Table 3). The in-hospital mortality did not differ significantly between women and men (14 vs 10%, p ¼ 0.246).
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Table 1. Demographics and Clinical Presentation Characteristic Age (years) Over 80 years old Under 65 years old Male gender Clinical presentation Current smoker Hypertension Diabetes mellitus Previous cardiac operation Previous CABG Previous AVR COPD Renal failure Coronary artery disease Prior Stroke Prior TIA MFS BAV Extent of dissection DeBakey I DeBakey II Ascending aortic diameter (cm) AI (mod-sev) Cardiac tamponade Cardiogenic shock Malperfusion One or more organs Coronary Cerebral Iliofemoral Gastrointestinal Spinal
No. (%) (n ¼ 489) 62 56 275 301
(53; 73) (11) (56) (62)
13 408 47 28 19 6 52 38 79 40 29 11 7
(3) (83) (10) (6) (4) (1) (11) (8) (16) (8) (6) (2) (1)
347 142 4.8 147 120 100
(71) (29) (4.3; 5.5) (30) (25) (20)
156 21 48 66 36 6
(32) (4) (10) (14) (7) (1)
Table 2. Surgical Procedures for Type A Aortic Dissection: Details and Outcome Variable Distal repair Hemiarch replacement Total arch replacement Thoracic aortic stent grafting Other procedures CABG Mitral valve repair CPB time (minutes) CX time (minutes) HCA time (minutes) In-hospital mortality
No. (%) (n ¼ 489) 468 (96) 21 (4) 60 (12) 7 3 205 135 35 56
(1) (1) (182; 239) (114; 162) (28; 47) (11)
CABG ¼ coronary artery bypass grafting; CPB ¼ cardiopulmonary bypass; CX ¼ cross-clamp; HCA ¼ hypothermic circulatory arrest. Categoric values are n (%), continuous values are median (first interquartile; third interquartile).
Aortic Root Reoperation Freedom from proximal reoperation was 100% 0%, 96% 1%, 92% 2%, and 89% 4% at 1, 5, 10, and 15 years, respectively (Fig 4). Seventeen patients (3%) (including 1 with MFS) at a median of 3.2 years (2.1; 6.5) postoperatively required proximal reoperations: 6 for pseudoaneurysm, 5 for severe aortic regurgitation (with concomitant mild, moderate, and severe calcification in 1 patient each), 3 for both aortic regurgitation and pseudoaneurysm, 2 for aortic regurgitation and root aneurysm, and 1 for graft infection. Four patients did
AI ¼ aortic valve insufficiency; AVR ¼ aortic valve replacement; BAV ¼ bicuspid aortic valve; CABG ¼ coronary artery bypass grafting; COPD ¼ chronic obstructive pulmonary disease; MFS ¼ Marfan syndrome; mod ¼ moderate; sev ¼ severe; TAV ¼ tricuspid aortic valve; TIA ¼ transient ischemic attack. Categoric values are n (%); continuous values are median (first interquartile; third interquartile).
Durability of Aortic Valve Resuspension Freedom from moderate or severe aortic valve regurgitation at follow-up did not differ between patients with initial no or mild valve insufficiency (99% 0%, 97% 1%, and 88% 3% at 1, 5, and 10 years, respectively) and those with initial moderate or severe valve insufficiency (98% 2%, 96% 2%, and 76% 9% at 1, 5, and 10 years, respectively) (log-rank, p ¼ 0.131), with 42 initial no or mild and 13 initial moderate or severe valve insufficiency patients remaining at risk at 10 years. Overall, 23 patients (5%) experienced moderate and 10 (2%) severe AI, and 3 patients (1%) experienced moderate and 2 (1%) severe aortic valve stenosis during the follow-up period.
Fig 3. Kaplan-Meier analysis of overall survival in patients who underwent aortic root repair for acute type A aortic dissection (number of events at 10 years: 165).
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Table 3. Multivariable Analysis of In-Hospital Mortality Risk Factors for Aortic Root Repair in Acute Type A Dissection Variable
OR
95% CI
p Value
Age >80 years Female gender Previous CABG Cardiopulmonary shock One or more organs with malperfusion Total arch replacement Cardiopulmonary bypass time
2.30 1.95 3.16 3.89 6.83
0.88-6.05 1.00-3.79 0.83-12.10 1.95-7.78 3.37-13.84
0.091 0.049 0.093 <0.001 <0.001
3.57 1.01
0.98-12.97 1.00-1.02
0.053 0.021
CABG ¼ coronary artery bypass grafting; val; OR ¼ odds ratio.
CI ¼ confidence inter-
not survive the secondary operation or the early perioperative period: 1 died of bowel ischemia 1 week after secondary aortic root replacement; 1 MFS patient died of ruptured descending thoracic aorta 10 days after uncomplicated aortic root (for pseudoaneurysm) and arch replacement; 1 patient was an intravenous drug abuser and died intraoperatively after attempted repair of proximal pseudoaneurysm accompanied by graft infection, aorto–right atrial fistula, and right ventricular failure; and 1 patient died of multisystem organ failure 4 days after aortic valve replacement and mitral valve repair for severe aortic valve stenosis and severe mitral valve insufficiency. Additionally, among 11 MFS patients, 1 more patient experienced severe AI 6 years after the primary operation but died of ruptured abdominal aneurysm before the scheduled redo operation, cumulating in two of 11 proximal aortic adverse events rate in MFS patients. None of the 7 BAV patients required proximal reoperation. One of them experienced moderate AI 18 years
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after the operation (at 83 years of age) and is treated medically.
Comment Operative Mortality of Standardized Approach to Type A Dissection The perioperative mortality rates in patients with acute type A dissection who undergo ascending aortic replacement with aortic root preservation have improved considerably over time and with increased operator experience, but they still differ widely (8% to 34%) [3, 5, 9]. Despite the high proportion of patients in cardiogenic shock (20%) and patients with malperfusion syndrome (32%), the 11% rate of in-hospital mortality in our series of 489 consecutive patients is within the lower end of the range in the published series. High-volume centers typically show improved results owing to their large practice and greater expertise. A major aspect of improving the outcomes in patients with type A dissection involves the use of a standardized perioperative approach. Our practice is to admit the patient directly to the operating room and to perform immediate operative repair, regardless of the patient’s condition and without any additional preoperative workup such as cardiac catheterization or cerebral imaging. The ascending aorta is replaced in all patients, aortic valve resuspension and sinus segment repair are performed whenever it is rational as previously described [7, 8], and all patients undergo routine open aortic arch replacement under hypothermic circulatory arrest. When we introduced our algorithm 20 years ago, we operated on fewer than 10 patients a year, and this standardized approach for infrequently performed procedures helped us to treat patients quickly and effectively. Now, on average 50 to 60 patients per year with acute type A dissection are operated on, and in 80% of them the aortic root is preserved.
Durability of Aortic Root Repair
Fig 4. Kaplan-Meier analysis of freedom from proximal reoperation (number of events at 10 years: 16).
The advantages of sinus segment and native aortic valve preservation are avoidance of coronary artery manipulation and its related potential adverse events, reduction of cross-clamp and cardiopulmonary bypass times, elimination of the risk of prosthetic valve endocarditis, and avoidance of a permanent need for anticoagulation in mechanical valve replacement. Anticoagulation therapy not only decreases the quality of life but also substantially inhibits aortic false lumen thrombosis. Patency of the false lumen in the descending aorta has been shown to be a strong independent risk factor for dissection-related late adverse events and death [10, 11]. In the current series, aortic dissection extended beyond the aortic arch in 71% of patients. More than half of the patients (56%) were younger than 65 years, and most of them might have required mechanical valve prostheses if they had undergone root replacement. Another option in such patients may be aortic root reimplantation, but this requires significantly more cardiac ischemic time, and the outcomes may be highly operator dependent.
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There is no doubt that the advantages of root preservation should be balanced against the risk of proximal reoperation in follow-up. Freedom from aortic root reoperation in patients who have undergone prior aortic repair for type A dissection with root retention has been reported to be between 69% and 95% at 10 years [3, 6, 12]. However, the limitation of those reports is the application of different aortic root repair techniques, which are strongly influenced by surgeons’ preferences. In the present series of standardized neomedia root repair, the freedom from aortic root reoperation at 10 years was 92%. Most root reinterventions were indicated by pseudoaneurysm or aortic valve regurgitation and only two of them by true aortic root aneurysm. We are unaware of any histologic studies that present the natural history of dissected sinus segment reconstructed with intramural Teflon felt, but the very low incidence of true root aneurysm after the neomedia repair supports its efficacy. Teflon felt has a profibrotic effect, frequently observed on reoperation in patients with Teflon used, for example, outside the aorta to reinforce the suture line. It is conceivable that placing the Teflon felt between dissected layers stabilizes the aortic root and prevents the development of aortic root aneurysm because of its profibrotic effect. Furthermore, the presence of Teflon felt in the media layer is very effective at preventing tears and bleeding from the needle holes in the dissected tissue. According to our experience with secondary root procedures performed in type A dissection patients operated on primarily at other institutions, a substantial number have secondary true root aneurysms, and in most of them the dissected sinus segment was not reconstructed with an intramural felt. The retrospective design of our study does not allow making a definitive statement; however, the neomedia concept applied in a large population with type A dissection showed very stable root reconstruction results. There were very few instances of reoperation for recurrent aortic insufficiency even though 30% of patients present primarily moderate to severe aortic insufficiency, which is indicative of the efficacy of this root repair technique to restore valvular geometry. In this series, 5 patients underwent proximal, secondary operations for severe AI. Recently, transcatheter aortic valve implantation, applying currently available devices, has been shown to be feasible in 43 patients with pure native aortic valve regurgitation [13]. Transcatheter aortic valve implantation is still only anecdotally used for AI without valve stenosis, but in the future it might be a treatment option for high-risk patients with aortic regurgitation or stenosis after operations for type A dissection.
Outcome in Patients With Genetically Triggered Type A Dissection In our cohort, 11 MFS patients underwent aortic valve resuspension and root repair in the emergency setting of acute type A dissection, inasmuch as their MFS diagnoses were not known at the time of operation, and their aortic roots were not dilated. One of them underwent a proximal secondary operation for pseudoaneurysm, and in 1 more patient secondary aortic valve replacement was
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indicated; however, this patient died of ruptured abdominal aorta before admission for a secondary operation. Reinforcing the sinus segment with a Teflon felt placed inside the aortic wall may prevent root dilatation in MFS patients also. However, our data do not allow us to recommend neomedia root repair in patients with MFS because the patient number is insufficient. Our policy in patients with diagnosed MFS and acute type A aortic dissection is to replace the aortic root or repair it by the means of the David reimplantation technique [14]. The Mayo Clinic group has recently demonstrated that nonreplaced sinuses of Valsalva in BAV disease after aortic valve replacement did not dilate at late follow-up [15]. In our series of neomedia root repair and aortic valve resuspension, none of the 7 BAV patients experienced aortic root aneurysm in the follow-up period, and 1 of them experienced moderate AI 18 years later and is currently being treated medically. However, more patients and longer follow-up times are required for the determination of long-term bicuspid valve and root durability. In conclusion, aortic root neomedia reconstruction and aortic valve resuspension can be successfully performed in the vast majority of patients with acute type A aortic dissection and are associated with low in-hospital mortality and low root reoperation rate in the long run. Therefore, liberal use of a composite graft replacement for type A dissection regardless of the root and valve predissection anatomy and function is not justified. We recommend that aortic root repair applying the Teflon felt neomedia concept and aortic valve resuspension should be considered in any case of acute type A dissection except for patients with aortic root aneurysm (>4.5 cm), aortic valve leaflet pathology or intimal tear extending into the sinus segment, and known connective tissue disorders.
References 1. Movsowitz HD, Levine RA, Hilgenberg AD, Isselbacher EM. Transesophageal echocardiographic description of the mechanisms of aortic regurgitation in acute type A aortic dissection: implications for aortic valve repair. J Am Coll Cardiol 2000;36:884–90. 2. Weinschelbaum EE, Schamun C, Caramutti V, Tacchi H, Cors J, Favaloro RG. Surgical treatment of acute type A dissecting aneurysm, with preservation of the native aortic valve and use of biologic glue. J Thorac Cardiovasc Surg 1992;103:369–74. 3. Mazzucotelli JP, Deleuze PH, Baufreton C, et al. Preservation of the aortic valve in acute aortic dissection: long-term echocardiographic assessment and clinical outcome. Ann Thorac Surg 1993;55:1513–7. 4. Halstead JC, Spielvogel D, Meier DM, et al. Composite aortic root replacement in acute type A dissection: time to rethink the indications? Eur J Cardiothorac Surg 2005;27:626–32. 5. Casselman FP, Tan ES, Vermeulen FE, Kelder JC, Morshuis WJ, Schepens MA. Durability of aortic valve preservation and root reconstruction in acute type A aortic dissection. Ann Thorac Surg 2000;70:1227–33. 6. Rylski B, Beyersdorf F, Blanke P, et al. Supracoronary ascending aortic replacement in patients with acute aortic dissection type A: what happens to the aortic root in the long run? J Thorac Cardiovasc Surg 2013;146:285–90. 7. Bavaria JE, Pochettino A, Brinster DR, et al. New paradigms and improved results for the surgical treatment of acute type A dissection. Ann Surg 2001;234:336–42.
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8. Geirsson A, Bavaria JE, Swarr D, et al. Fate of the residual distal and proximal aorta after acute type A dissection repair using a contemporary surgical reconstruction algorithm. Ann Thorac Surg 2007;84:1955–64. 9. Dell’aquila AM, Concistre G, Gallo A, et al. Fate of the preserved aortic root after treatment of acute type A aortic dissection: 23-year follow-up. J Thorac Cardiovasc Surg 2013;146:1456–60. 10. Akutsu K, Nejima J, Kiuchi K, et al. Effects of the patent false lumen on the long-term outcome of type B acute aortic dissection. Eur J Cardiothorac Surg 2004;26:359–66. 11. Park KH, Lim C, Choi JH, et al. Midterm change of descending aortic false lumen after repair of acute type I dissection. Ann Thorac Surg 2009;87:103–8.
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12. Von Segesser LK, Lorenzetti E, Lachat M, et al. Aortic valve preservation in acute type A dissection: is it sound? J Thorac Cardiovasc Surg 1996;111:381–91. 13. Roy DA, Schaefer U, Guetta V, et al. Transcatheter aortic valve implantation for pure severe native aortic valve regurgitation. J Am Coll Cardiol 2013;61:1577–84. 14. Rylski B, Bavaria JE, Beyersdorf F, et al. Type A aortic dissection in Marfan syndrome: extent of initial surgery determines long-term outcome. Circulation 2014;129: 1381–6. 15. Park CB, Greason KL, Suri RM, Michelena HI, Schaff HV, Sundt TM 3rd. Fate of nonreplaced sinuses of Valsalva in bicuspid aortic valve disease. J Thorac Cardiovasc Surg 2011;142:278–84.
DISCUSSION DR RICHARD J. SHEMIN (Los Angeles, CA): This is a very nice case presentation. In the evolution of this technique, did you ever use BioGlue and then abandon it? Also, what is the thickness of the felt used in the media? Is it the standard-thickness felt that we often use for outer reconstruction and buttressing, or is it a special-order, thinner felt to fit nicely in the media? DR DESAI: I’ll answer your second question first. The felt is the regular felt. It’s a thick felt. There are some subtleties in putting the felt in, and particularly not to oversize it too much because that thick felt is pretty stiff, but a standard beveled piece works very well. In terms of BioGlue, number one, our practice has changed over time and, number two, varies a little bit between the different surgeons. We traditionally have reported this technique to use BioGlue to help glue the felt in place and then oversew it. I think that we have limited the amount of glue we use significantly. Occasionally we use a couple of drops here or there, but not in any major way. DR SHEMIN: So would you recommend that glue alone is insufficient, that the felt is the better technique? DR DESAI: Felt is a better technique. DR SHEMIN: I have a follow-up question. Obviously you described aortic roots that are relatively small. Has this made you rethink the indications for elective procedures? When people are referred with a root between, say, 4.5 and 4.8, where it’s clearly larger than the descending aorta by one and a half or close to two times, have you considered elective procedures on these patients instead of waiting for a dissection in an otherwise clinically relatively normal root? DR DESAI: That is a good point. We have looked at our data. We are presenting this at the AATS as well: the issue of size. In fact, a multinational study that we did with Bartosz Rylski, who is one of our fellows who put this together with Martin and a whole group of centers in the United States that is coming out in JACC shortly, looked at this concept of how big the aorta is when it dissects and how much it grows after it dissects. In our own experience, 80% to 90% of patients when they dissect probably had an aortic dimension that was less than 4.5 cm. We don’t really understand who dissects. There is a genetic component, clearly. Size has something to do with it, and certainly when you are in the 6-plus range or 5.5 range, it is an important indicator. We don’t know what the denominator is for the 4-cm aortas as to how many people have 4-cm aortas and what proportion of those dissect, but there is probably some genetic or biochemical
marker that we can use to identify them. Size is not the only criterion. DR SHEMIN: So what is your lower level of elective procedures if you do look at size criteria? DR DESAI: I think we generally stick with the size criteria by the guidelines: 5.5 for a standard atherosclerotic aneurysm, 5 to 5.5 for a bicuspid, and 4 to 4.5 for someone with a clear genetic syndrome, like Loeys-Dietz or Marfan. DR TOMAS D. MARTIN (Gainesville, FL): I would first like to compliment you and the University of Pennsylvania team for your results, and particularly the system you have set up for care of these patients. My first question really had to do with glue, but I think you have probably answered that. We still use a combination of felt inside and outside and glue to create the neomedia. You might comment again on why you think your technique might be better than that. I really wanted you or Dr Bavaria to comment particularly on your use of central cannulation. In today’s world, everybody talks about how you have to cannulate the axillary artery. We do not routinely cannulate the axillary artery. You use central cannulation most frequently over a wire, and many people don’t even understand that. If you wouldn’t mind commenting on that and why you think that might be better, I would appreciate it. DR DESAI: We adopted that technique probably about 7 or 8 years ago. The key thing is to look at the preoperative imaging to understand where the true lumen is. Again, we are going to be presenting our whole series of this at the AATS in April. There are two approaches to this. Number one is to either put the needle through the false lumen, through the flap, and into the true, or to try to cannulate the true directly. In our experience, most of the time we do the former; we go through the false lumen with the needle, advance it slowly until you feel it hit the flap, and then push it a little, and the blood stops coming through it, an 18-gauge needle, and then you push it a little bit farther, and then you have nice pulsatile bright red blood. We pass the wire down. We have a TEE probe in the descending aorta, and we look for the wire in the true lumen in the descending aorta. In certain situations we will also use epiaortic ultrasound to help identify which lumen is where. Then we just serially dilate and then put in a standard long femoral cannula, an 18F femoral cannula. DR ROBERT B. LEE (Paducah, KY): I have two questions. It was a great presentation, clear, concise, and reproducible. When you
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RYLSKI ET AL AORTIC ROOT REPAIR IN TYPE A DISSECTION
put your neointima in, it looks like the only suture line is above at the aortic level, at the anastomosis level. Are you putting any sutures at the bottom of the implant? DR DESAI: No, definitely not. DR LEE: And the second question is simple too. Have you ever considered using bovine pericardium as opposed to felt? DR DESAI: We think that the felt has a lot of beneficial effects in terms of scarring in that noncoronary sinus so it doesn’t dilate later, but it is very thrombogenic on the inside, and even if there was a little residual flow through a needle hole or something like that, it tends to thrombose it. We do have a follow-up study looking at some of the echocardiography and computed tomography parameters of these roots, and what we
Ann Thorac Surg 2014;-:-–-
have seen is that the aortic root actually shrinks down around this felt. DR JOHN W. FEHRENBACHER (Indianapolis, IN): Have you ever seen a pseudoaneurysm in the noncoronary sinus in your postoperative follow-up? DR DESAI: No, not in that series, none. DR FEHRENBACHER: We have seen pseudoaneurysms when glue alone was used for dissections involving the sinuses, so we always use felt sandwich in addition to glue. DR DESAI: Yes, in patients who have tears within the root below the sinotubular junction, we have seen it.