Bentall procedure in ascending aortic aneurysm
Ascending aorta aneurysm disease (AAAD) is characterized by its low frequency, heterogeneity and risk of rupture and dissection, complications that determine the high mortality of 94 to 100%.
These are clear indications for the need for urgent surgery.
The determining factors of these complications are the diameter of the aorta and the underlying disease; therefore, the indication of elective surgery is essential.
It is documented that an aortic diameter >5 cm has a risk of rupture and dissection up to 45% per person/year.
However, independent of the pathogenic mechanism of AAAD, the natural tendency of aneurysms is to progressively increase, with the average rate recorded as 0.42 cm/year (range: 0.1-0.52 cm/year).
The decision for surgical treatment is multifactorial and is established by the anatomic features of the aorta, underlying disease, risk of anticoagulation, age of the patient and presence of active infection, among others.
Various surgical techniques have been developed that reflect the evolution in the management of AAAD, each with advantages, limitations and specific risks.
Root replacement and ascending aorta with a tubular valved graft called the Bentall procedure is considered as an option for treatment of AAAD accompanied by annuloectasia.
This technique has shown low morbidity and mortality (1.7 to 17%) and a 5-year survival rate of 73 to 92%, being 60 to 73% at 10 years.
However, surgical mortality can vary dramatically according to hospital experience, medical equipment, disposable resources and heterogeneity of patients.
At the Hospital de Especialidades, Centro Medico Nacional de Occidente, IMSS, Guadalajara, Jalisco, the Bentall procedure is the technique used for the reconstruction of the ascending aorta; however, information is unavailable documenting hospital mortality. Therefore, the objective of this study was to determine the frequency of hospital mortality of AAAD surgically treated using the Bentall procedure in our hospital.
Figure 1. Aneurysm associated with aortic dissection and annuloectasia.
Materials and Methods We performed a descriptive study that included 23 patients with AAAD who were surgically treated with the Bentall procedure in the referred hospital between March 1, 2005 and September 30, 2008. Clinical information was obtained from medical records. Studied variables were hospital mortality, which corresponded to deaths occurring within the first 30 days postoperatively. Hospital mortality associated with surgical technique was determined from the following reasons: postoperative bleeding, dehiscence or perianastomotic leak at the level of the coronary ostia and distal and proximal anastomosis of the tubular graft to the aorta, pseudoaneurysm formation and acute coronary event. Hospital mortality unrelated to surgical technique was determined by cerebral vascular event, systemic inflammatory response, postoperative heart failure, pulmonary failure, nosocomial pneumonia, and postoperative renal failure.
Indications for emergency surgery were acute aortic dissection, hematoma of the aortic wall, NYHA functional class III, acute and severe aortic insufficiency, myocardial or distant organ infarction, and acute endocarditis. Indications for elective surgery were an aortic root diameter >5.5 cm or growth rate of 0.5 cm/year or more, diameter of 5 cm in Marfan syndrome or bicuspid aortic valve, insufficiency or severe aortic stenosis and symptomatic regardless of aneurysm size, with ejection fraction <50% and significant dilatation of left ventricular: telediastolic diameter >75 mm or telesystolic >55 mm. The Bentall procedure was performed in all patients through a median sternotomy with cardiopulmonary bypass (CPB) through the cannulation in the ascending aorta or in the femoral artery when aortic dissection and right atrial cannulation were presented (Figure 1). With moderate systemic hypothermia (30-32ºC), the ascending aorta was clamped and cardiac arrest was carried out with cold hyperkalemic crystalloid cardioplegia and local hypothermia. Aneurysm identification was done with longitudinal aortotomy and resection of the native aortic valve (Figure 2). Anastomosis of the valved tubular graft (Carbomedics, Austin, TX) with the aortic valve ring was performed with 2-0 continuous polypropylene suture (Figure 3). Cauterization was managed with two holes over the graft and through these the coronary ostia were implanted with 5-0 polypropylene suture (Figure 4). If the aneurysm was confined to the ascending aorta and was not associated with dissection, the graft was measured and the distal anastomosis to the aortic clamp was completed. In the presence of dissection, modification of the technique consisted of placing Teflon material to plicate the aortic wall and the graft in order to obliterate the false lumen and reinforce the anastomosis (Figure 5). The warm-up was begun, aortic and left chambers were purged through the aortic root and right upper pulmonary vein. After completing the distal and proximal anastomosis, the residual aortic wall was sutured around the tubular graft (Figure 6). Cabrol fistula was performed with a polytetrafluoroethylene (PTFE) graft of 8 mm or with the plicature of the right atrial appendage towards the remaining aortic tissue, with the object of avoiding a hematoma in the periprosthetic space. The procedure was completed conventionally. Descriptive statistics were used and analysis was performed sing the SPSS (Statistical Package for Social Sciences) v.8.0
program for Windows. Sciences) v.8.0 program for Windows.
Figure 3. After resection of the native valve, proximal anastomosis is performed of the tubular valve graft of the aortic ring.
Results There were a total of 1862 cases of cardiac surgery carried out from March 1, 2005 to September 30, 2008 at the Hospital de Especialidades. The procedures on the ascending aorta corresponded to 1.2% (23 cases). Average age of presentation of the AAAD was 46 years (range: 16-74 years). Males were more affected in 19/23 cases (83%) (M:F ratio 4.7:1). The most frequent etiology was nonspecific degeneration of the middle layer associated with valvular disease in 10 cases (43%), principally represented by cystic necrosis of the middle layer in 39% (nine cases) and 4% (one case) by atherosclerosis. The bivalve aorta represented 22% (five cases), genetic diseases of Marfan and Turner syndrome types and poststenotic aneurysms were 9% (two cases each), Takayasu disease and ankylosing spondylitis with 4% (one case for each) (Table 1). Heart disease coexistent with AAAD occurred in six patients (26%) and consisted of aortic coarctation in two cases (9%), ischemic heart disease, interatrial communication, severe mitral insufficiency and subaortic membrane, one case of each (4%) (Table 2). The indication for emergency surgery occurred in six cases (26%), manifested by aortic dissection and hematoma in 22% (5 cases) and NYHA functional class III in 4% (1 case). Elective surgery was performed in 17 cases (76%), aneurysmal size being the main indication for 15 cases, with average diameter of 63 mm at the time of the diagnosis and growth of 1.5 cm/year for poststenotic aneurysms
Figure 4. Coronary ostia are anastomosed to the tubular Dacron graft with 5-0 polypropylene continuous suture.
Table 1. Etiology of AAAD n = 23 % Nonspecific degenerative aneurysms • Cystic degeneration of the middle layer • Atherosclerosis Bivalve aortic valve Marfan syndrome Turner syndrome Poststenotic aneurysms Takayasu disease Ankylosing spondylitis 10 91522211 43 39 4 22 99944 AAAD, ascending aortic aneurysm disease. The procedures for the treatment of AAAD were Bentall surgery in 20 cases (87%), of which four cases (20%) were supplemented with Cabrol fistula and aortoplasty with prosthetic valve implant in three patients (13%). Concomitant procedures were performed in four cases (17%), which consisted of myocardial revascularization, closure of interatrial communication, mitral valve implant and resection of subaortic membrane (Table 3). Hospital complications occurred in eight cases (35%): abnormal bleeding with mediastinal exploration in four cases (17%), nosocomial pneumonia in three cases (13%), isolated as the causative bacteria Candida albicans and Staphylococcus haemolyticus, disturbances in the conduction and pace in three cases (13%) and septic shock in two cases (9%) (Table 4). Mortality accounted for three cases (13%): septic shock secondary to nosocomial pneumonia in two cases
Figure 5. In cases of type A aortic dissection, Teflon material was placed to obliterate the
false lumen and reinforce the anastomosis.
Figure 6. After completing the distal and proximal anastomosis, the residual aortic wall was sutured around the tubular graft (inclusion technique).
Pubblicato da: Dr. Mauro Di Marino