When to Operate on the Bicuspid Valve Patient With a Modestly Dilated Ascending Aorta

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1 When to Operate on the Bicuspid Valve Patient With a Modestly Dilated Ascending Aorta Christian D. Etz, MD, PhD, Stefano Zoli, MD, Robert Brenner, MS, Fabian Roder, MS, Moritz Bischoff, MD, Carol A. Bodian, DrPH, Gabriele DiLuozzo, MD, and Randall B. Griepp, MD Departments of Cardiothoracic Surgery and Anesthesiology, Mount Sinai School of Medicine, New York, New York; and Heartcenter Leipzig, Germany Background. Bicuspid aortic valves (BAV) are frequently associated with root/ascending aorta dilatation, but there is controversy regarding when to operate to prevent dissection of a dilated aorta associated with a well-functioning BAV. Methods. From 1988 through 2008, 158 patients (mean age: years) with a dilated ascending aorta (AA) and a well-functioning BAV were referred to our institution. All patients underwent computed tomographic (CT) scanning and digitization to calculate mean AA diameter. Forty-two patients underwent operation a median of 52 days after initial CT scan with a mean AA diameter of cm. One hundred sixteen patients (mean diameter cm) were enrolled in annual or semiannual surveillance. Seventy-one patients, 45 with 2 or more CT scans, are still under surveillance. Results. Average follow-up was years. Overall survival after the first encounter was 93% at 5 years and 85% at 10 years. A total of 87 of 158 patients had a Bentall or Yacoub procedure, with two hospital deaths (2.3%). Mean duration of surveillance in the 116 patients without immediate operation was years (481 patientyears). Average growth rate of the AA in patients with 2 scans or greater was 0.77 mm/year (p < versus normal population) with no significant impact of hypertension, sex, smoking or age. Forty-five of the 116 surveillance patients underwent operation after a mean of years (mean age years; mean AA diameter cm). Six patients died without surgery, median age 82 (range, 44 to 87) years, but none within one year of the last CT scan. Conclusions. A consistent approach to patients with a well-functioning BAV and AA dilatation, recommending operation to those with an AA diameter greater than 5 cm and deferring operation in patients under surveillance in the absence of significant enlargement (>0.5 cm/year), resulted in overall survival equivalent to a normal agematched and sex-matched population. Operation was necessary in approximately 10% of patients under surveillance each year. (Ann Thorac Surg 2010;90: ) 2010 by The Society of Thoracic Surgeons Bicuspid aortic valves (BAV) are frequently associated with root/ascending aorta (AA) dilation, but there is controversy regarding when to operate to prevent dissection of a dilated aorta associated with a well-functioning BAV [1 3]. The dilated or aneurysmal ascending aorta (AA) is at risk for spontaneous rupture and dissection, and the magnitude of this risk is closely related to the size of the aorta and the underlying pathology of the aortic wall [4 6]. The AA diameter remains a strong indication for preventive surgery in patients with inherited connective tissue disorders because the occurrence of rupture and dissection adversely alters natural history and survival even after successful emergency surgical treatment [7, 8]. In patients with BAV and valvular indications for surgery, the accompanying AA dilation is treated at the time Accepted for publication June 16, Presented at the Fifty-sixth Annual Meeting of the Southern Thoracic Surgical Association, Marco Island, FL, Nov 4 7, Address correspondence to Dr Etz, Mount Sinai School of Medicine, Department of Cardiothoracic Surgery, One Gustave L. Levy Place, PO Box 1028, New York, NY 10029; christian.etz@mountsinai.org. of valve surgery. Currently, most centers replace the AA during valve surgery for dysfunctional BAV when the diameter exceeds 4.5 cm [1, 9]. The aim of this report was to assess whether patients with BAV, a modestly dilated AA, and no significant comorbidities can safely be followed with periodic surveillance rather than preemptive surgery without an unacceptable risk of rupture or dissection. Patients and Methods From 1988 through 2008, 158 consecutive patients (mean age: years) with a dilated AA and a wellfunctioning BAV were referred to the Mount Sinai Medical Center (Fig 1). All patients underwent computed tomographic (CT) scanning and digitization according to a standard protocol to calculate the cross-sectional area of the AA and its mean diameter. Forty-two patients underwent operation a median of 52 days after an initial CT scan with a mean AA diameter of cm. A total of 116 patients (mean diameter cm) were enrolled in annual or semiannual surveillance. Seventy by The Society of Thoracic Surgeons /$36.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg ETZ ET AL 2010;90: WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 1885 Fig 1. Between 1988 and 2008, a total of 158 consecutive patients with functionally normal bicuspid aortic valves (BAV) and ascending aortic dilatation were surveyed. Forty-two patients with a mean ascending tubular diameter of cm underwent immediate surgery. One hundred sixteen patients entered the surveillance program with initial mean tubular ascending diameters of cm; 45 had two or more digitized computed tomographic scans at least 150 days apart. Another forty-five patients with a mean tubular ascending diameter of cm underwent surgery an average years after their first scan. Twenty-six patients had one scan only. one patients, 45 with 2 or more CT scans, are still under surveillance. A retrospective review of these patients was conducted using data gathered contemporaneously in our departmental database and supplemented from patient records. This research was approved by the Mount Sinai Institutional Review Board and individualized patient consent was not required. Assessment of Aortic Size Chest CT scans taken at different times and possibly at different facilities are difficult to compare with any accuracy. Even estimating the maximal diameter of the AA in serial studies poses a problem because of possible oblique angles at which diameter may be measured. For these reasons, digitization of the scans according to a fixed protocol was begun at our institution in the early 1990s, and has been the method which we have used to assess the size and growth of the aorta since the beginning of this study. The method for digitization of our CT scans and calculation of the AA diameter has previously been described in detail [10]. Computed tomographic digitization was used to assess the entire aorta periodically during surveillance (Fig 2). Serial CT scans were digitized, providing a threedimensional drawing of the AA, the transverse arch, and the descending and thoracoabdominal aorta. The tubular AA was individually identified in each three-dimensional reconstruction. Thereafter, an estimate of the diameter of the tubular AA was calculated using the mean of the minor diameters of all ellipsoid CT slices contributing to the tubular AA. The areas of these cross-sectional slices were also ascertained but analysis of the data did not find any advantage in using area rather than, or in addition to, diameter. Surgical Technique All patients included in the surgical arm of this study had a button Bentall operation, a modification of the original technique described by Kouchoukos and colleagues in 1991 [11], a valve sparing root repair (root remodeling, Yacoub) [12], or ascending aorta replacement with or without aortic valve replacement. All Bentall operations were performed with an open distal anastomosis using a period of deep hypothermic circulatory arrest. Our current technique and its rationale have previously been described in detail [13]. Briefly, cannulation for cardiopulmonary bypass was through the femoral artery in the majority of the patients (although in the last years, cannulation of the right axillary artery has become the standard approach especially in patients with atherosclerotic aneurysms) [14]. To protect the heart, crystalloid or blood cardioplegia was infused directly into the coronary ostia, and topical cooling was employed. Thorough systemic cooling to a temperature of 12 to 15 C was carried out to avoid an upward drift of the temperature during the period of circulatory arrest. A left ventricular vent was placed through the right superior pulmonary vein to allow decompression of the heart. A composite of a St. Jude valve (St. Jude Medical, St. Paul, MN) and a Hemashield graft (Boston Scientific Corp, Wayne, NJ) was used in cases for which a mechanical valve was indicated. For a prosthetic valve, the sutures were placed from the aorta to the ventricular aspect of the annulus to effect intraannular fixation of the

3 1886 ETZ ET AL Ann Thorac Surg WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 2010;90: Fig 2. Typical drawing of the 3D reconstruction of the aorta based on individually digitized CT scan as used to assess the entire aorta periodically during surveillance. Serial CT scans were digitized, providing diameter and area data of the ascending aorta, the transverse arch, and the descending and thoracoabdominal aorta. The tubular ascending aorta was individually identified in each 3D reconstruction and an estimate of the diameter of the tubular ascending aorta was calculated using the mean of the minor diameters of all ellipsoid CT slices contributing to the tubular ascending aorta. valve. In cases in which a biologic valve was chosen, a home-made composite, consisting of a pericardial valve (Edwards Lifesciences, Irvine, CA) and a Hemashield graft, was used. After sizing the aortic annulus, a series of pledgeted mattress sutures were placed from the ventricular to the aortic aspect of the annulus for fixation of the composite prosthesis in an epiannular position. After the proximal suture line was completed, the diseased aortic segment was resected, and buttons including the coronary ostia were excised. The first centimeter of the coronary arteries was mobilized and the buttons were implanted in an-end-to-side fashion with a running suture incorporating a polytetrafluoroethylene (Teflon) felt strip (Meadox Medical Inc, Oakland, NJ) to reinforce the adventitial surface of the coronary arteries. To allow the open distal anastomosis or the total aortic arch reconstruction, the head was placed downward, cardiopulmonary bypass was discontinued, and the aorta was trimmed appropriately for the extent of the replacement. The anastomosis between the trimmed polyethyleneterephthalate fiber (Dacron; DuPont, Wilmington, DE) graft and the aorta was performed with a 3-0 Prolene (Ethicon, Somerville, NJ) running suture, reinforced by an outer Teflon felt strip. Before resuming cardiopulmonary bypass, the head vessels were carefully aspirated to remove air and particulate debris. In a few cases, selective cerebral perfusion using the Mount Sinai Y-arch technique, as previously described in detail [15], was carried out. In cases thought to have an especially high risk of embolization, a brief period of retrograde perfusion through the superior vena cava, at a pressure of 20 mm Hg, was performed. Cardiopulmonary bypass was discontinued when an esophageal temperature of 34 to 36 C was reached. Follow-Up All patients were followed by the referring cardiologist and contacted periodically by our research personnel. The follow-up questionnaire included medications, cardiac events or operations, cerebral, visceral, or peripheral thromboembolic events, hemorrhage, endocarditis, and anticoagulant intake, and was completed in all cases by the patients themselves, their cardiologists, or close family members. In patients who underwent surgery, postoperative events were compiled and analyzed according to the Guidelines for Reporting Morbidity and Mortality after Cardiac Valvular Operations and our institutional checklist [16]. In addition, patients who were not immediately referred for operation were scheduled for repeat CT scans which were digitized and analyzed either annually or twice yearly, depending upon the clinical indications. Follow-up of patients under surveillance was 100% complete, with a median of 10.9 (6.4 to 19.5) years, and was closed on September 26, Statistical Methods Data were entered in an Excel spreadsheet (Microsoft Corp, Redmond, WA) and transferred to an SAS file (SAS Institute Inc, Cary, NC) for data description and analysis. Patient and disease characteristics are described as percents, median (range) or means (standard deviation). Growth rates of ascending diameters were estimated under a repeated measures model implemented with SAS Proc Mixed. Survival probabilities are estimated from Kaplan-Meier life tables. We also estimated the annual death rate for this group per person-year of follow-up, as well as the standardized mortality ratio. This gives the observed numbers of deaths relative to the number that would be expected based on New York State population death rates for comparable ages, genders, and follow-up times. Statistical significance of the standardized mortality ratio was tested under a Poisson model, implemented with SAS Proc Genmod. Results The follow-up of all 158 patients averaged years (range, 0 to 18; 1,027 patient-years). Eighty-seven patients underwent either immediate surgery (n 42), or reached criteria for surgery during surveillance and were operated on subsequently (n 45). Among the 87 patients who underwent surgery, 73 patients had a Bentall procedure; 32 patients (mean age years) with a mechanical valve (St. Jude Medical, 21 to 31 mm) and 41 patients (mean age years)

4 Ann Thorac Surg ETZ ET AL 2010;90: WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 1887 with a biologic valve (Carpentier-Edwards Perimount 21 to 29 mm; Edwards Lifesciences). Ten patients (mean age years) underwent ascending aorta replacement, six without and four with aortic valve replacement (2 mechanical, 2 biologic). Four patients (mean age years) had a valve-sparing aortic root repair (Yacoub) procedure. In eight patients, the ascending aneurysm had atherosclerotic features. Three patients had chronic type A dissection, one from a clamp injury after coronary artery bypass grafting four years earlier. All but one patient, with an 8-cm aneurysm but a past medical history of prostatic cancer who developed acute chest pain and severe aortic regurgitation, were operated on electively. Two patients died before discharge from the hospital (2.3%). Immediate Surgery Forty-two patients (mean age years), with a mean AA diameter of 5.6 (5.1 to 7.4) cm, underwent surgery after a median of 52 days after initial evaluation (Figs 1; 3). No patient with a well-functioning BAV and a tubular AA diameter below 5 cm underwent immediate surgery (Fig 2). Thirty-six patients had a Bentall procedure: 18 with a mechanical valve (mean age years) and 18 with a biologic valve (mean age 68 8 years). Five patients (mean age years) had an isolated ascending aorta replacement. One patient (47 years old) had a valvesparing (Yacoub) procedure. There was one hospital death in this group (2.2%). A 76-year-old man with severely calcified BAV and coronary artery disease underwent a biologic Bentall procedure and coronary artery bypass grafting, and died on the first day postoperatively of severe biventricular heart failure. Four patients died later during follow-up after surgery at a median age of 67 (52 to 83) years. A 52-year-old patient was discharged to a rehabilitation center, but was readmitted 3 weeks after surgery with Fig 3. Tubular AA diameter at index computed tomographic scan versus age of each individual patient entering the program; patients under surveillance (n 116) versus immediate surgery (n 42). (Data for normal ascending aorta (*) and normal ascending aorta: upper limit (*) are from Hannuksela M, Lundqvist S, Carlberg B. Thoracic aorta dilated or not? Scand Cardiovasc J 2006;40:175 8.) pancreatitis and pneumonia and died of sepsis on day 32 postoperatively. The remaining three patients, all of whom had serious other medical problems, died 2, 4, and 8 years postoperatively; one of a fatal stroke, one of confirmed myocardial infarction, and another one with terminal lung cancer. The long-term survival after immediate surgery was 89.4% after 5 years and 84.7% after 10 years of follow-up (Fig 6). Elective Surgery During Surveillance Forty-five patients (mean age years) underwent elective surgery years after their initial evaluation revealed a mean tubular AA diameter of cm; no patient in the surveillance group underwent urgent or emergent surgery. The mean number of scans was 4.3 per patient. The primary indication for surgery was an absolute diameter increase to 5.5 cm or above in 24 (53%) patients and rapid growth in 13 patients (29%). Eight (13%) patients had aneurysm-related symptoms, and 2 (4%) had worsening symptomatic aortic regurgitation. At least 13% (6 patients) presented with a combination of the above-mentioned indications for surgery. Twenty-three patients (mean age years) had a biologic Bentall procedure, and 14 patients (mean age years) had a Bentall procedure with a mechanical valve. Five patients (mean age 69 6 years) had a replacement of the ascending aorta from the sinotubular ridge; one without valve surgery, two with a mechanical, and two with a biologic valve. Three patients (58, 50, and 26 years of age) had a valve-sparing root replacement (Yacoub) operation. There was one hospital death among patients who underwent elective surgery after a period of surveillance (2.2%). A 74-year-old patient died 32 days after aortic root replacement during reoperation for aortic root and mitral valve endocarditis. Four patients died later during follow-up at a median age of 77 years (75 to 81). One patient, age 73, who had a concomitant history of malignancy, coronary artery disease, and arrhythmia, died 49 days postoperatively of congestive heart failure. The remaining three deaths, in elderly patients with substantial comorbidities, occurred several years postoperatively. Surveillance One hundred sixteen patients were followed with annual or twice yearly scans for a mean of years (481 patient-years; Figs 1; 5). On average, the diameter of the tubular ascending aorta in the last scan during surveillance on these patients (in 45 patients with 2 or more scans) was 4.6 cm (3.5 to 5.5). Diameter data from greater than 400 digitized CT scans were included in the growth analysis. The average overall growth rate in the tubular portion of the ascending aorta was 0.77 mm per year (p ; Fig 5). The rate of growth was not associated with hypertension, male sex, history of smoking, or age, nor was it associated with the diameter of the aneurysm. Adherence to the surveillance program was not uniformly compulsive. Of those who had more than one

5 1888 ETZ ET AL Ann Thorac Surg WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 2010;90: Fig 4. Long-term outcome of patients with bicuspid aortic valves (BAV) and ascending aortic dilatation that underwent immediate surgery (N 42) versus patients who entered the surveillance program (N 116) with or without elective surgery. scan, the median interval between scans was 0.68 years and 11% of scans were more than 1.25 years apart. Long-Term Outcome Overall survival after the first encounter was 93% after 5 years and 85% after 10 years (Fig 5). Sixteen of 158 patients died during follow-up, yielding an overall linearized risk of death of 1.6% per patient-year. When compared with an age-matched and sex-matched New York State population for 2002 (Fig 6), the number of observed deaths for the entire cohort was 16 versus 17.3 expected for the normal controls (observed to expected ratio 0.93). The long-term survival under surveillance (116 patients), with or without elective surgery (45 patients), was 94% after 5 years and 84% after 10 years (Fig 4). Fig 6. Long-term outcome of patients (N 158) with BAV and ascending aortic dilatation (Kaplan-Meier survival curve starting with the first encounter) versus age-matched and sex-matched NY State population. Six patients died without operation during surveillance, at a median age of 82 years (44 to 87), 1.0, 2.0, 2.4, 3.6, 3.8, and 7.7 years after the last recorded CT scan. Their AA diameters at the time of their last scans ranged from 4.3 to 5.2 cm. No patient under surveillance died within one year of their last CT scan. The youngest patient died at age 44, several years after kidney transplantation for end-stage renal failure. His death was 2 years 4 months after his last CT scan evaluation, which showed an AA diameter of 4.4 cm. A 65-year-old patient was found dead 3 years and 9 months after only a single CT scan showing an ascending aortic diameter of 4.3 cm. An 84-year-old hypertensive smoker with COPD and known coronary artery disease died of a myocardial infarct 15 months after his last CT scan evaluation showed an AA diameter of 5.2 cm. Another patient with a history of coronary artery bypass grafting, diabetes, stroke, and hypertension died at age 81, 3 years and 7 months after his last CT scan evaluation showed an AA diameter of 5.0 cm. Similarly, an 87-year-old patient with diabetes, hypertension, and pulmonary stenosis died 2 years after his last CT scan evaluation showed an ascending aorta diameter of 5.0 cm. Another patient died at age 85 of metastatic colon cancer, 7 years and 9 months after his last CT scan showed an AA diameter of 4.7 cm. Fig 5. Average growth of the ascending aorta in patients (n 116) with normally functioning bicuspid aortic valve versus normal, agerelated expansion. (Data for dotted line in this figure are derived from Hannuksela M, Lundqvist S, Carlberg B. Thoracic aorta dilated or not? Scand Cardiovasc J 2006;40:175 8.) Comment Patients with BAV have increasingly been recognized to have an enhanced risk of development of aneurysms and dissections of the AA [3, 4, 17 18]. This has led to periodic surveillance of the AA in patients with BAV, and early replacement of the AA in conjunction with other indications for cardiac surgery, chiefly aortic valve dysfunction [1, 18]. Although a consensus has developed about the guidelines for replacement of the AA in such patients, with most surgeons agreeing that a diameter exceeding 4.5 cm warrants replacement of the AA if surgery is being done on a patient with BAV for valvular or other intracardiac pathology, there is more of a dilemma when

6 Ann Thorac Surg ETZ ET AL 2010;90: WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 1889 considering what to do with patients with BAV and modest dilatation of the AA without any concomitant cardiac problems warranting operation [6, 19, 20]. The updated guidelines of the AHA 2008 [21] and the Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology [22] regarding the management of BAV-associated AA aneurysms are based on observational studies and expert consensus, and therefore still somewhat controversial [21, 23]. The AHA recommends surgery to repair the aortic root or replace the AA in patients with BAV if the diameter of the aortic root or AA is greater than 5.0 cm or if the rate of increase in diameter is 0.5 cm per year or more (level of evidence: C). In patients with BAV undergoing aortic valve replacement because of severe aortic stenosis or regurgitation, repair of the aortic root or replacement of the AA is recommended if the diameter of the aortic root or AA is greater than 4.5 cm (level of evidence: C). Our approach has been to follow these patients with CT scans and standardize the evaluation of these scans, which are repeated at least annually, in order to be able to compare them meaningfully and in order to calculate the growth rate of the aorta [9]. Previous studies have suggested that risk of rupture and of dissection of the aorta may be related to diameter and valve function [6]. There is also some evidence that rapid growth of the aneurysm is a risk factor for rupture-dissection, and consequently most surgeons feel that a growth rate exceeding 1 cm per year warrants surgery. Our decision to restrict our measurements and growth calculations to the AA was to enable accurate serial measurements for the purpose of this study, but we realize that these data do not capture all the dimensions of interest in the aortic root and AA. We are currently using volumetric measurements of the aorta from the sinuses to the innominate artery to try to obtain a fuller picture for the future of the rate of progression of dilatation of the AA in patients with BAV without valve dysfunction. Others have interesting data with regard to wall stiffness, as reflected by echocardiography. Variables other than aortic enlargement are also factored into a decision in favor of operation: advanced age, poorly controlled hypertension, smoking, and chronic obstructive pulmonary disease have all been shown to increase the risk of rupture. In this study we failed to identify any of these as significant risk factors for more rapid aortic expansion, but we had only small numbers of patients and had excluded those with the largest diameters and most rapid growth by referring them for operation before successive measurements 6 months apart could be done to evaluate growth. In recent years, the possibility of electively replacing the AA while sparing the aortic valve has been extended to patients with BAV by some surgeons with excellent results [24]. This holds out promise that a durable operation which does not involve mandatory anticoagulation may be possible for patients with a well-functioning BAV. Furthermore, recent evidence suggests that even the traditional modified Bentall procedure with a mechanical valve may not carry as high an associated risk of thromboembolic and bleeding complications as had been reported earlier, possibly because of less aggressive anticoagulation and increasingly sophisticated monitoring of Coumadin (DuPont, Wilmington, DE) use. Thus the elective replacement of the AA with relatively minimal mortality and morbidity is possible for patients with BAV deemed to have significant risk of rupture, as confirmed by our low short-term mortality. The relatively low risk of elective operation has engendered a tendency to recommend operation electively for asymptomatic patients with very modest AA dilatation [1]. The data on growth rate in those patients with BAV who had two scans at least six months apart (Fig 4) show that the rate of expansion of the aorta in patients with BAV with age is significantly faster than the growth of the aorta calculated in a normal population of patients with tricuspid aortic valves [25]. Nevertheless, AA growth in these patients with BAV is still quite slow, averaging only 0.77 mm per year. This observation is in the same range as found in other studies using a variety of serial measurement techniques, including echocardiography. Ferencik and colleagues [17] found a mean of diameter progression of 0.9 mm/year at the proximal ascending aorta in 68 patients with BAV, albeit with dysfunctional valves in 60%. Davies and colleagues [26] reported even more pronounced AA diameter increases of 1.9 mm/year in 70 patients in a BAV cohort with 100% dysfunctional BAV; there was a trend toward higher aortic growth in patients with stenosis. The exclusion of patients with serious valvular dysfunction from our cohort may account for our somewhat lower calculated rate of AA expansion as both aortic stenosis and aortic insufficiency have been shown to correlate with accelerated aneurysm growth. Our more conservative estimates of aortic enlargement may also stem from our use of minimal diameters at the site of maximal expansion of the AA rather than diameters measured on possibly oblique views from echocardiographic or CT scans. We think the reliability of our measurements, carried out in a strictly standardized manner from our CT scan reconstructions, is likely to be very high. In this small series of patients, we did not demonstrate a significant difference in growth rates between patients who required surgery at some point during surveillance and those who continued to be followed without requiring an operation. It should be borne in mind that, in accordance with accepted guidelines, strict blood pressure control and beta blocker treatment was recommended for all patients enrolled in the surveillance program. This study was an attempt to see whether our current criteria for assessing risk of rupture or dissection are succeeding in preventing aneurysm-related deaths in this relatively low-risk population. The data suggest that sudden unexplained deaths, conceivably due to aneurysm rupture or dissection, did not occur among those who adhered reasonably faithfully to the surveillance protocol. The results after surgery were also favorable, with two operative deaths among the 87 patients referred for surgery and one additional death within the first year

7 1890 ETZ ET AL Ann Thorac Surg WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 2010;90: that was likely also linked to the operation. These observations suggest that a more aggressive approach, involving earlier surgical intervention, is probably not indicated in asymptomatic patients with well-functioning BAV and modest dilatation of the aorta. The data are consistent with the idea that waiting until a diameter of 5 cm is reached in the AA is a safe strategy, and raise the possibility that it may be reasonable to defer operation even longer in patients under surveillance if the only indication is aortic size. It is important, however, that patients be carefully watched. We cannot rule out the possibility that some patients elected not to enter the surveillance program after an initial consultation showed only modest aortic dilatation, and then suffered rupture years later, or that some underwent operation elsewhere after their first visit. The initial evaluation establishing that mild dilatation of the aorta is present in conjunction with BAV offers an opportunity to emphasize to the patient the importance of antihypertensive medication, the need for periodic surveillance, and the kinds of symptoms that might suggest an urgent need for surgical intervention. Even though our data show that many patients did not adhere strictly to the recommended 6-month interval for radiographic surveillance, the other benefits of being in the surveillance program, such as smoking cessation, more attentive hypertensive treatment, and use of beta blockers, may have contributed to the favorable outcome of our strategy in these patients. A consistent approach to patients with a wellfunctioning BAV and modest AA dilatation, recommending operation to patients with an AA diameter greater than 5 cm, and placing those with smaller aortas in a surveillance program with periodic scanning and deferral of operation unless significant enlargement greater than 0.5 cm/year occurs, resulted in survival equivalent to that of a normal age-matched and sex-matched population. Growth averaged 0.77 mm/year, and operation was required in about 10% of patients annually. The results for the entire cohort are predicated on a low operative mortality ( 2%), and reasonably faithful adherence to a regimen of annual CT scans. Our observations do not preclude the possibility that a similar regimen with use of an even larger decision diameter (for example 5.5 cm) would achieve an equally good outcome. References 1. Svensson LG, Kim KH, Lytle BW, Cosgrove DM. Relationship of aortic cross-sectional area to height ratio and the risk of aortic dissection in patients with bicuspid aortic valves. J Thorac Cardiovasc Surg 2003;126: Russo CF, Mazzetti S, Garatti A, et al. Aortic complications after bicuspid aortic valve replacement: long-term results. Ann Thorac Surg 2002;74:S1773 6; discussion S Edwards WD, Leaf DS, Edwards JE. Dissecting aortic aneurysm associated with congenital bicuspid aortic valve. Circulation 1978;57: Roberts CS, Roberts WC. Dissection of the aorta associated with congenital malformation of the aortic valve. J Am Coll Cardiol 1991;17: Coady MA, Rizzo JA, Hammond GL, Kopf GS, Elefteriades JA. Surgical intervention criteria for thoracic aortic aneurysms: a study of growth rates and complications. Ann Thorac Surg 1999;67:1922 6; discussion Davies RR, Goldstein LJ, Coady MA, et al. Yearly rupture or dissection rates for thoracic aortic aneurysms: simple prediction based on size. Ann Thorac Surg 2002;73: Elefteriades JA. Natural history of thoracic aortic aneurysms: indications for surgery, and surgical versus nonsurgical risks. Ann Thorac Surg 2002;74:S ; discussion S Neri E, Barabesi L, Buklas D, et al. Limited role of aortic size in the genesis of acute type A aortic dissection. Eur J Cardiothorac Surg 2005;28: Etz CD, Homann TM, Silovitz D, et al. Long-term survival after the Bentall procedure in 206 patients with bicuspid aortic valve. Ann Thorac Surg 2007;84: Dapunt OE, de Asla RA, Griepp EB, Midulla PS, Griepp RB. Computer-generated 3D representations of the aorta: a new tool in the management of aortic aneurysm patients. Thorac Cardiovasc Surg 1994;42: Kouchoukos NT, Wareing TH, Murphy SF, Perrillo JB. Sixteen-year experience with aortic root replacement. Results of 172 operations. Ann Surg 1991;214: Sarsam MA, Yacoub M. Remodeling of the aortic valve anulus. J Thorac Cardiovasc Surg 1993;105: Ehrlich MP, Ergin MA, McCullough JN, et al. Favorable outcome after composite valve-graft replacement in patients older than 65 years. Ann Thorac Surg 2001;71: Etz CD, Plestis KA, Kari FA, et al. Axillary cannulation significantly improves survival and neurologic outcome after atherosclerotic aneurysm repair of the aortic root and ascending aorta. Ann Thorac Surg 2008;86: Hagl C, Ergin MA, Galla JD, et al. Neurologic outcome after ascending aorta-aortic arch operations: effect of brain protection technique in high-risk patients. J Thorac Cardiovasc Surg 2001;121: Edmunds LH Jr, Clark RE, Cohn LH, Grunkemeier GL, Miller DC, Weisel RD. Guidelines for reporting morbidity and mortality after cardiac valvular operations. Eur J Cardiothorac Surg 1996;10: Ferencik M, Pape LA. Changes in size of ascending aorta and aortic valve function with time in patients with congenitally bicuspid aortic valves. Am J Cardiol 2003;92: Braverman AC, Güven H, Beardslee MA, Makan M, Kates AM, Moon MR. The bicuspid aortic valve. Curr Probl Cardiol 2005;30: Borger MA, David TE. Management of the valve and ascending aorta in adults with bicuspid aortic valve disease. Semin Thorac Cardiovasc Surg 2005;17: Song HK, Bavaria JE, Kindem MW, et al. Surgical treatment of patients enrolled in the national registry of genetically triggered thoracic aortic conditions. Ann Thorac Surg 2009; 88: Bonow RO. Bicuspid aortic valves and dilated aortas: a critical review of the ACC/AHA practice guidelines recommendations. Am J Cardiol 2008;102: Vahanian A, Baumgartner H, Bax J, et al. Guidelines on the management of valvular heart disease: The Task Force on the Management of Valvular Heart Disease of the European Society of Cardiology. Eur Heart J 2007;28: Guntheroth WG. A critical review of the American College of Cardiology/American Heart Association practice guidelines on bicuspid aortic valve with dilated ascending aorta. Am J Cardiol 2008;102: Schäfers HJ, Aicher D, Langer F, Lausberg HF. Preservation of the bicuspid aortic valve. Ann Thorac Surg 2007;83: S740 5; discussion S Hannuksela M, Lundqvist S, Carlberg B. Thoracic aorta dilated or not? Scand Cardiovasc J 2006;40: Davies RR, Kaple RK, Mandapati D, et al. Natural history of ascending aortic aneurysms in the setting of an unreplaced bicuspid aortic valve. Ann Thorac Surg 2007;83:

8 Ann Thorac Surg ETZ ET AL 2010;90: WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 1891 DISCUSSION DR WILLIAM T. RYAN (Dallas, TX): I would like to congratulate the authors on a well-done paper that plagues most of us out in practice. I think it is a great attempt to try to address a very difficult problem. I have one comment and then three questions. The comment I have is basically that the absence of age, sex, hypertension, smoking, and initial diameter speaks to a genetic mechanism for this disease, and each year we get up at these meetings and talk about that, but with 3% of the population afflicted with this disease, it seems that we could do more in outlining the genetic population that is most affected and most at risk with blood studies and genomic studies, and I think that is long overdue. Hopefully somebody will do that. The first question I have is your immediate surgery group and your surveillance group had a huge number of patients who overlapped in size of ascending aorta at first diagnosis; 24 of your 45 patients with aortas of 5.5 cm or less. So my first question is, when we are out there and we see a patient at the first encounter, what size would you tell us that we should take a good risk patient to the operating room? DR ETZ: We probably, if you go 10 to 15 years back, would have said 5.5 cm and during the last couple of years there were more reports that you should go earlier, and so in the last decade I think the threshold went down and would probably have said 5 cm is a reasonable risk. With the data we see now in the retrospective analysis, we would probably go back and say if we have somebody with 5 cm, we would probably wait and see what the growth rate is. So we probably would be a little bit more conservative with the knowledge from these data. DR RYAN: I think that is exactly most of our practices. I mean, most of us have said 5 cm would go to the OR [operating room] at first encounter, but your data suggests they can be followed. The second question is rapid growth was an indication for surgery in about 30% of your surveillance group, and you outlined the recommendations in the AHA [American heart Association] guidelines. Realizing your data is a bit different from those guidelines, tell us what growth rate we need to watch for before we operate. DR ETZ: For the most part, I think the 0.5 cm of the AHA guidelines are reasonable. It always depends on which level you really look at, and you have got to be very careful which data you compare. Even with these data that were gathered in a standardized fashion from the CAT [computerized axial tomographic scans], we sometimes had huge differences from one to the other scan because people looked at the wrong area or the CAT scan wasn t perfectly perpendicular. So I think 0.5 cm is reasonable, and you can always go and, say, go do a biannual scan rate and look at six months again if you are not sure. DR RYAN: I think that your digitization is something that probably ought to be a standard way to follow these to get a more accurate aortic size and growth rate. And the final question I have alludes to the level at which you measured and the operations you did. So, in other words, you were just measuring growth rate of the ascending aorta, but the vast majority of your patients got root replacements. DR ETZ: That s right. DR RYAN: And so the question that I have is, is there any correlation either at operation or with echo between your aortic root size and your ascending aortic size and how did the interplay of those two factors affect your decision to operate? DR ETZ: There certainly is an association because it is connected. We decided for technical reasons not to choose the root diameters for the study because it is just a very short type of root and you can never be sure that your 3 mm scans are exactly the maximum diameter. But there is a connection. Just for analysis purposes, it was more convenient to use the tubular ascending aorta. We believe that there is, as you mentioned, a congenital or genetic problem: obviously it affects the root, and it is not a good idea to leave affected tissue behind. That is why most of the patients had a Bentall. That was not clear in the beginning of this study period and that is why there were some patients that had ascending replacements. But that is why they all get root replacements currently. DR LARS G. SVENSSON (Cleveland, OH): I enjoyed your paper because I think it confirms some things that we have been wondering about. You referred briefly to the European data where they have actually recommended surgery at 4 cm, and we have felt that that is too aggressive. We have a paper that we are working on with 1,800 bicuspid valve patients, and we found that if you operated below 4.5 cm, that really wasn t necessary. In fact, in that group of patients with an aorta less than 4.5 cm, only.07% required another operation in 10 years, and our freedom from reoperation was 98% at 10 years if you operated on patients with a size more than 4.5 at with a concurrent aortic valve procedure. The other point that you brought up was when to operate. We found in our patients with aortic dissection that this seemed to correlate with cross-sectional area and height, and so we use cross-sectional area divided by height in meters and if the ratio is more than 10, we recommend surgery. You have touched also on growth rates. This is something that Nick Kouchoukos and I and others have struggled with the guidelines coming out for aortic surgery from AHA, AATS, [American Association for Thoracic Surgery] ACC [American College of Cardiology], STS [Society of Thoracic Surgeons], and there are no good data, but I think your paper adds further evidence that we can probably be more conservative in these patients, and the event rate later down the road is low and tracking growth rates is reasonable. At the moment, the criteria we recommended is that if you are doing someone with a bicuspid valve and the aorta is more than 4.5 cm, then you should fix the aorta, and that is based on Tirone David s data and the Cleveland Clinic data. So your data is good additional data for us to reference. Thank you. DR ETZ: Thank you very much, Dr Svensson. Maybe one short comment. We made the same observation in the past few years and that is why we started using volume data that would incorporate the height as well as the diameter of the aorta, and we hope that we get some useful information from that in the next couple of years. DR ANTHONY L. ESTRERA (Houston, TX): Good job, Christian. I would submit to you that maybe being more aggressive might be a viable option, because 40% of your patients did require a replacement at 3.4 years. The question I have, though, is related to the normal aortic valve and the ones that got initial

9 1892 ETZ ET AL Ann Thorac Surg WHEN TO OPERATE ON THE ASCENDING AORTA IN A PATIENT WITH BAV 2010;90: replacement. How many of those patients required an aortic valve later on? Can we leave those aortic valves alone, the bicuspid aortic valve that is normal? Thank you. DR ETZ: That is certainly a very good, very important question. If you would ask Professor Schaefers from Germany, he would probably say yes, you can; you just repair it. We were not convinced in the majority of cases and that is why most of them had a Bentall procedure, about 50% with a mechanical valve and 50% with a biological valve. We don t have the data to answer that question at this point. I think if you are an expert in repairing it, you might risk it. Otherwise, a Bentall is a safe option. The Society of Thoracic Surgeons Policy Action Center The Society of Thoracic Surgeons (STS) is pleased to announce a new member benefit the STS Policy Action Center, a website that allows STS members to participate in change in Washington, DC. This easy, interactive, hassle-free site allows members to: Personally contact legislators with one s input on key issues relevant to cardiothoracic surgery Write and send an editorial opinion to one s local media senators and representatives about upcoming medical liability reform legislation Track congressional campaigns in one s district and become involved Research the proposed policies that help or hurt one s practice Take action on behalf of cardiothoracic surgery This website is now available at by The Society of Thoracic Surgeons Ann Thorac Surg 2010;90: /$36.00 Published by Elsevier Inc