Long-Term Experience of Girdling the Ascending Aorta With Dacron Mesh as Definitive Treatment for Aneurysmal Dilation

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1 Long-Term Experience of Girdling the Ascending Aorta With Dacron Mesh as Definitive Treatment for Aneurysmal Dilation Oved Cohen, MD, Jonah Odim, MD, PhD, David De La Zerda, MD, Chidi Ukatu, MD, Raj Vyas, BS, Neil Vyas, BA, Kathy Palatnik, BS, and Hillel Laks, MD Division of Cardiac Surgery, David Geffen School of Medicine at University of California, Los Angeles, Los Angeles, California Background. The management of the mildly to moderately dilated ascending aorta (3.5 to 4.9 cm) in cardiac surgery remains controversial. Therapeutic options have included radical aortic resection with synthetic graft substitution, external aortic reinforcement or wrap, with or without partial aortic wall excision, and a watch-andwait approach. We reviewed our institutional experience with Dacron (DuPont, Wilmington, DE) mesh wrap support of dilated ascending aortas. Methods. During the last 20 years, 102 patients with aneurysmal dilatation of the ascending aorta underwent wrapping of the ascending aorta with a fine Dacron mesh from the ventricular-aortic junction to the origin of the innominate artery. For the last 10 years, the wrap was anchored to the aortic annulus with pledgeted sutures. Aortic diameters up to 6 cm, without focal areas of thinning, were wrapped. Aortic diameters exceeding 6 cm, or with focal thinning, underwent tailored aortic wall resection and wrapping. Primary end points of the study included mortality, aortic diameter growth, dissection or rupture, or both. Results. The mean age of the group was years (range, 12 to 90 years). A single patient underwent aortic wrapping without cardiopulmonary bypass. Sixty-six patients (65%) required additional aortic valve surgery. Five patients (5%) had reinforcement of dilated sinuses with glutaraldehyde-treated pericardial patches combined with wrapping. Twenty-seven patients (26%) had combined coronary and valve surgery, and 2 patients had coronary revascularization alone. There was neither early nor hospital mortality. Among the 81 patients (79%) we were able to contact, 7 (7%) late deaths had occurred at 0.5, 1, 3, and 9 years after operation that were unrelated to aortic Before the era of excisional therapy with synthetic graft replacement for aortic aneurysms, less drastic attempts were made to reduce aortic wall tension by various forms of banding, using a variety of synthetic materials: cellophane, polyethylene, and Gore-Tex Presented at Aortic Surgery Symposium X, New York, NY, April 27 28, Address correspondence to Dr Cohen, Division of Cardiac Surgery, David Geffen School of Medicine at UCLA, Le Conte Ave, Rm B, CHS, Los Angeles, CA ; oved.cohen@gmail.com. pathology. Various levels of follow-up were obtained in the 88 patients (86.2%). In 78 patients, echocardiograms, computed tomography angiograms, or magnetic resonance angiograms were obtained. In 2 of these patients, aneurysmal dilatation of the sinuses developed below the wrap and reoperation was required. No patient in whom the mesh wrap was anchored to the aortic annulus required reoperation. All 81 patients that were contacted by us and monitored by referring physicians were asymptomatic and free of problems related to the aorta. The mean ( SD) preoperative diameter of the ascending aorta was mm (range, 35 to 87 mm), the postwrap intraoperative diameter was mm (range, 20 to 40 mm), and the follow-up postoperative aortic diameter was mm (range, 27 to 52 mm). The mean average change in the aortic diameter during the follow-up period was mm (range, 7 to22 mm), a mean of 8%. The mean follow-up period was 5.7 years (median, 4.77 years; range, 9 days to 21 years). There were no infections or other early complications related to the wrap. Conclusions. Dacron mesh support of the moderately dilated aneurysmal ascending aorta, alone or in conjunction with coronary revascularization, aortic root surgery, or valvular operations, or both, is safe and durable. Dacron mesh is transparent and stretchable, permitting tight girdling of the aorta. These properties prevent hematoma formation, facilitate proximal vein graft anastomoses, and provide visualization and access to aortic suture lines. Finally, this technique retards further aortic dilation, altering the natural history of aortic aneurysms. (Ann Thorac Surg 2007;83:S780 4) 2007 by The Society of Thoracic Surgeons (W.L. Gore & Associates, Flagstaff, AZ). Some of these methods failed from compression atrophy of the artery or development of new aneurysmal areas not originally externally reinforced [1, 2]. Aortic wrapping or girdling, with or without partial resection, is an alternative to graft replacement for selected aneurysms of the ascending aorta ( 5 cm) [3 8]. In instances of a dilated ascending aorta (4 to 5 cm), the Dacron (DuPont, Wilmington, DE) mesh wrap can be used to reduce aortic diameter, reduce wall tension according to the law of Laplace, and prevent 2007 by The Society of Thoracic Surgeons /07/$32.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg AORTIC SURGERY SYMPOSIUM X COHEN ET AL 2007;83:S780 4 GIRDLING THE ASCENDING AORTA FOR DILATION S781 further dilation and complications of aneurysms, including rupture and dissection. In 1991, we first described a technique of wrapping the dilated aorta to reduce diameter and prevent future enlargement and to prevent dissection and rupture [3]. This technique was considered an alternative to resection and graft substitution. Ten years later, Odim and colleagues [4] presented excellent intermediate-term follow-up in 48 consecutive patients in whom this strategy had been used. We now present our long-term results of aortic girdling in 102 consecutive patients that potentially alters the natural history of dilated and aneurysmal ascending aortas before the hinge-point diameter of 6 cm, when the hazard for the complications of rupture and dissection significantly escalates. Table 2. Operative Factors Factor N (%) a CBP time (min) (0 312) Aortic cross-clamp time (min) (0 234) Dacron wrap only 5 (5) Dacron wrap CABG 2 (2) Dacron wrap AVR 66 (65) Dacron wrap CABG AVR 17 (17) Dacron wrap other 7 (7) Dacron wrap CABG AVR other 5 (5) a Continious variables presented as mean (Range) or number (%). AVR aortic valve replacement/repair; CABG coronary artery bypass grafting; CBP cardiopulmonary bypass. Patients and Methods Table 1. Demographic and Comorbid Factors Factor N (%) Male gender 83 (81) Age (years) a (12 to 89) Age distribution (years): (39) (18) (25) (14) 80 6 (6) Coronary artery disease 25 (25) Prior MI 6 (6) Aortic valve disease 81 (80) Mitral valve disease 18 (18) LVH 38 (37) Rheumatic heart disease 18 (18) Congenital heart disease 11 (11) Marfan syndrome 5 (5) Previous cardiac operation 14 (14) Diabetes Mellitus 4 (4) Hypertension 37 (36) Chronic renal failure 6 (6) Tobacco use 22 (22) a Age is presented as mean (range). LVH left ventricular hypertrophy; MI myocardial infarction. This study involved review of medical records, operative notes, echocardiograms, computed tomography angiograms (CTA) or magnetic resonance angiograms (MRA), cardiac catheterization data, and outpatient records of all patients undergoing fine Dacron mesh wrapping of the ascending aorta as a central feature, or combined with another cardiac procedure, at our institution. Primary end points of this retrospective study were mortality and freedom from aortic reoperation. Secondary end points were aortic diameter growth or enlargement and complications, including aortic rupture and dissection. Growth of the ascending aorta was determined from serial measurements of the maximal diameters of the ascending aorta derived from echocardiography or CT or MR imaging. This study was approved by the University of California, Los Angeles Institutional Review Board for patient-oriented outcome-based clinical research. The board also waived the need for patient consent to the study. From August 1984 through September 2003, 102 patients (19% women) underwent the wrap procedure for dilated and aneurysmal aortic disease. The mean age was years (range, 12 to 89); half (50 of 102) of the group was aged older than 60 years. Most of the patients had other cardiovascular and systemic comorbidities: 80% had aortic valve disease, 11% had associated mitral valve disease, 25% had important coronary artery occlusive disease, and 11% had congenital heart disease. Systemic comorbidities included hypertension in 36%, tobacco abuse in 22%, chronic renal failure in 18%, and diabetes mellitus in 4% (Table 1). Concomitant cardiac procedures Fig 1. Operative view shows the mechanism of girdling the dilated ascending aorta with fine Dacron mesh and gradual narrowing of diameter with multiple right-angle clamps secured with multiple interrupted 3-0 polypropylene mattress sutures.

3 S782 AORTIC SURGERY SYMPOSIUM X COHEN ET AL Ann Thorac Surg GIRDLING THE ASCENDING AORTA FOR DILATION 2007;83:S780 4 Surgical Technique The heart and great vessels are exposed through a median sternotomy. An epicardial echocardiographic scan is performed to evaluate atheromatous involvement of the aorta, wall thickness, aortic dimensions, and aortic valve function. The aortopulmonary window is dissected free, and the ascending aorta is completely mobilized from the main and right pulmonary artery to the pericardial reflection. A fine Dacron mesh wrap (Boston Scientific, Medi-Tech, Wayne, NJ) is then passed around the ascending aorta (Fig 1) and anchored in the area of the noncoronary sinus with anchoring sutures that are placed through the mesh with pericardial pledgets. The mesh is prepared by cutting a triangle to accommodate the left coronary artery (Fig 2), and is then passed just above the right coronary artery and the left main coronary artery and is cinched up in the mid ascending aorta to reduce the diameter of the aorta to 3.5 cm. Anchoring sutures placed in the annulus of the noncoronary sinus are passed through the mesh and reinforced with bovine pericardial pledgets. The edges of the mesh are anchored without tension below the aortic incision above the right coronary artery. The wrap is then anchored to the pericardial reflection at the level of the innominate artery. The upper and lower edges of the mesh are not excessively tightened to avoid compression of the left coronary artery and erosion at the edge of the mesh (Fig 3). At the end of the procedure, a transesophageal echocardiogram is performed to demonstrate the size and appearance of the ascending aorta and the function of the aortic valve. Follow-Up Follow-up was conducted over the last 6 months and was possible in 88 (86.2%) of 102 patients. The follow-up echocardiogram data and medical condition and status were obtained from the referring cardiologists. The mean follow-up period was years (range, 0.06 to 21 years). End points of this study were early and late mortality, freedom from reoperation, and late valve function. In 78 patients, we had an updated and recent echocardiogram, CTA, or MRA. Eighty patients were contacted directly and are asymptomatic and doing well. Fig 2. Dacron mesh technique of wrapping the dilated ascending aorta with suture fixation in the noncoronary sinus at the ventricular aortic junction, with care taken not to compromise the right and left coronary arteries, and distal anchoring at the pericardial reflection at the take-off of the innominate artery. were required in 97 patients (95%): 65% had wrap and aortic valve replacement (AVR), 17% had wrap, coronary artery bypass grafting (CABG), and AVR; and 2% had wrap and CABG. In addition, 7 patients had an aortic wrap and another cardiac procedure, and 5 patients had an aortic wrap, CABG, AVR, and another cardiac procedure (Table 2). Fig 3. Final operative view demonstrates aortic diameter reduction of a dilated aneurysmal ascending aorta with fine Dacron mesh wrap.

4 Ann Thorac Surg AORTIC SURGERY SYMPOSIUM X COHEN ET AL 2007;83:S780 4 GIRDLING THE ASCENDING AORTA FOR DILATION S783 Table 3. Echocardiographic Follow-Up Measurement a AAD Change Pre-Op AAD Patients (n) Pre-Op (mm) Intra-Op (mm) Latest Follow-Up In mm % 50 mm (32 49) (20 39) b (27 52) ( 5 22) 8% 50 mm (50 87) (20 40) (28 45) ( 7 12) 8% Total (32 87) (20 40) (27 52) ( 7 22) 8% a Data are presented as mean (range). b A 12-year-old child with Marfan syndrome had an AAD of 20 mm. AAD maximal ascending aortic diameter; mm millimeter. Results Mortality There was no hospital or early mortality. Seven late deaths occurred at 0.5, 1, 3, and 9 years postoperatively, but none were related to aortic pathology. Two individuals died after acute myocardial infarction. One patient developed end-stage heart failure and subsequently underwent orthotopic heart transplantation. He died suddenly after transplantation. One patient died of cerebrovascular accident or stroke. In 3 patients the causes of death were not identified. Aneurysmal dilatation of the sinuses below the wrap developed in 2 patients and required reoperation. Since we started anchoring the wrap to the ventricular-aortic junction at the level of the noncoronary sinus 10 years ago, we have not seen this phenomenon. During the last 6 months, 81 patients were successfully contacted. They had neither cardiovascular symptoms nor known problems related to the ascending aorta and root. The mean ( SD) preoperative diameter of the ascending aorta was mm (range, 35 to 87 mm), the mean postwrap intraoperative diameter was mm (range, 20 to 40 mm; Table 3), and the mean latest follow-up aortic diameter was mm (range, 27 to 52 mm; Table 3). The average change in aortic diameter during the follow up period was mm (range, 7 to 22; Table 3), an average of 8%. The mean follow-up period was 5.7 years (median, 4.77 years; range, 9 days to 21 years). Comment The ideal reparative technique for ascending aortic aneurysms remains elusive despite important progress and refinements in surgical technique and management. Although graft replacement for an ascending aortic aneurysm is now performed relatively safely and remains the accepted surgical procedure, we cannot ignore the hospital mortality of 4.5% to 20% and morbidity that such extended operations carry [9 12], particularly in our aging and sickly population. A less physiologically intrusive technique that is safe, effective, and reproducible, and that can be performed with cardiopulmonary bypass, or without for isolated aneurysms of the ascending aorta, Fig 4. Histopathologic cross-section trichrome staining of aorta wrapped with fine Lars Dacron mesh (arrows) in white light and polarized light demonstrates the absence of hematoma formation between the wrap and aortic adventitia and no erosion of mesh through the wall. There is severe fibrosis in the outer half of the aortic wall (A), with diffuse loss of elastic tissue in the media. The medial degenerative changes of the media are associated with adventitial fibrosis with foreign body giant cell reaction associated with the presence of the Dacron wrap. This 33- year-old man with Marfan syndrome underwent aortic valve repair with subcommissural annuloplasties, repair of sinuses with glutaraldehyde-treated pericardial patches, and Dacron mesh wrap of the ascending aorta. Two years later, he required aortic valve repair for severe insufficiency.

5 S784 AORTIC SURGERY SYMPOSIUM X COHEN ET AL Ann Thorac Surg GIRDLING THE ASCENDING AORTA FOR DILATION 2007;83:S780 4 is certainly an attractive option. In this respect, the indications for aortic wrapping, risks of the procedure, and late complications are pertinent to the debate about surgical approach. Indications for the aortic wrap or girdle are greatly influenced by aortic morphology and pathology. Of the three principal forms of dilation poststenotic, annuloaortic ectasia (marfanoid), and tubular the poststenotic form, which represents about 13% of all ascending aneurysms, appears most suitable for this procedure, especially if the patient who undergoes aortic valve replacement is elderly or is at high risk for any other reason. There is general agreement that patients with ascending aneurysms with a diameter exceeding 6 cm (hinge point for increased hazard for rupture and dissection), those that are saccular rather than fusiform or have significant dilatation of either the annulus or sinuses, or both, should not undergo aortic wrapping [13]. In the case of important connective tissue disease, such as Marfan syndrome, the hinge point is earlier, at a diameter of 5.5 cm. In recent years, there has been a growing tendency to wrap the dilated ascending aorta over replacement in certain circumstances, despite continued suspicion about the efficacy of this strategy. Some studies report good short-term and medium-term results [13 19]. In our 20- year experience with the Dacron mesh wrap remodeling technique for treatment of the dilated ascending aorta, we have witnessed neither a significant increase in ascending aortic diameter at follow-up nor rupture or dissection. In addition, save for 2 patients in whom the proximal extent of the wrap was not secured to the aortic annulus in the noncoronary sinus early in our experience, we have not seen any complications or new aneurysmal changes. In view of this experience, we believe that proximal and distal anchorage is critical to prevent displacement of the wrap. The safety of the wrap is confirmed by histology (Fig 4), which reveals no evidence of infection, invasion, or erosion of the synthetic mesh through the aortic wall. The retrospective and nonrandom design of this study and the small number of patients who were lost to follow-up limit the conclusions that can be drawn. It is important to recognize that the findings of this long-term study may not apply to patients who have symptomatic ascending aortic aneurysms or asymptomatic pathology with a diameter exceeding 6 cm. 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