Long-term outcomes after repaired acute type A aortic dissections
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《血管的通路杂志》
a Department of Adult Cardiac Surgery, Timone Hospital, Marseille, France
b LERTIM, Medicine Faculty, Marseille, France
Presented at the Aortic Surgery Symposium X, 27–28 April 2006, New York.
Abstract
The aim was to evaluate long-term outcomes after surgical treatment of acute type A dissection. Between 1993 and 2004, 199 consecutive patients were operated on for acute type A dissection. All survivors were included in an MRI follow-up program. Follow-up time averaged 4.45 years. Overall survival was 96%, 80% and 65% at 1, 5 and 10 years. The false lumen remained patent in 101 cases (69%). Predicitve factors for thrombosis of the false lumen were age >70 years old and valve-sparing aortic root reconstruction. Significant risk factors for patency of the distal false lumen were age <50 years old, De Bakey type III retrograde dissections, Bentall procedure and long-term anticoagulation. Freedom from reoperation was 98%, 96% and 69% at 1, 5 and 10 years. Eight patients required reoperations for dilatation of distal aorta at 4.7±2.8 years after the first operation. Reoperations consisted of combined surgical and endovascular procedures, without in-hospital or late deaths. Close MRI follow-up demonstrated that aortic false lumen remained patent in a majority of cases. Surgical reconstruction needing long-term anticoagulation must be avoided when possible to decrease patency of the false lumen. However, late reoperations are infrequent and can be treated with a low risk by using endovascular procedures.
Key Words: Aortic dissection; Magnetic resonance imaging; Reoperation
1. Introduction
The aim of surgical management of acute type A aortic dissection is to prevent death by rupture of the ascending aorta [1]. Because of the extent of the disease to the entire aorta, most surviving patients continue to have a patent distal false lumen [1], potentially leading to aneurysmal evolution and its complications, especially the rupture, that is the first cause of late death [2]. It has been recognized that the long-term prognosis of the patients with thrombosed false lumen is superior to that of those with patent false lumen [3]. The following study was undertaken to evaluate long-term outcomes and significant risk factors for patency of the false lumen, dissecting aneurysm evolution and reoperations after surgical treatment of acute Stanford type A dissection.
2. Material and methods
2.1. Patients
Between January 1993 and December 2004, a total of 199 consecutive patients underwent emergency surgical repair for spontaneously occurring acute Stanford type A aortic dissection in the Department of Adult Cardiac Surgery at Timone Hospital, Marseille, France.
One hundred and forty-seven patients were discharged from the hospital. There were 112 men (76%) and 35 women (24%), and their mean age was 60.6±13 years (range 30–88).
Demographics and clinical data are shown in Table 1. Mean additive EuroSCORE [4] was 9.3±2.3.
Data were collected from September to December 2004.
2.2. Anatomy
According to De Bakey classification [3], 106 patients (72%) were type I, 24 patients (16%) were type II and 17 patients (12%) were type III with retrograde extension. Locations of the primary intimal tear are listed in Table 2.
2.3. Surgical procedures
Cardiopulmonary bypass was established by median sternotomy after retrograde femoral artery cannulation. Cardiac arrest was obtained by retrograde administration of cold crystalloid cardioplegia into the coronary sinus, sometimes completed by antegrade administration in the coronary ostia. After aortic cross clamping the ascending aorta was opened, and the aortic root was inspected and repaired during systemic cooling.
Concerning the proximal aortic repair, replacement of the supracoronary ascending aorta and aortic valve resuspension was performed in 80 cases (54%), composite graft replacement of the aortic valve, sinuses, and ascending aorta with the modified Bentall technique was performed in 32 cases (22%), separate replacement of the supracoronary ascending aorta and aortic valve was performed in four cases (3%), and in 31 patients (21%) the aortic root was replaced and the aortic valve was reimplanted (valve-sparing aortic root reconstruction) according to David [5] in six cases (4%) and according to Yacoub [6] in 25 cases (17%).
Concerning the distal repair, circulatory arrest was used in 89 cases (60%). Deep hypothermic circulatory arrest (DHCA) at 15–20 °C alone was used in 15 cases (17%), associated with antegrade selective cerebral perfusion (ASCP) in 52 cases (58%) or retrograde cerebral perfusion (RCP) in the superior vena cava in 22 cases (25%). This was achieved with a hemi arch replacement in 71 cases (48%) and a total arch replacement in 18 cases (12%). In the remaining 58 patients (40%) the distal anastomoses were made under aortic cross clamping just proximal to the in nominate artery.
Proximal and distal anastomoses were made with 3-0 or 4-0 monofilament sutures reinforced by polytetrafluoroethylene band. Gelatin-resorcinol-formaldehyde (GRF) biologic glue (Colle biologique; Fii, Saint Just Malmont, France) was used in 17 cases (12%), and Tissucol fibrinous glue (Immuno AG; Vienna, Austria) was used in 139 cases (95%).
Marfan syndrome was present in six cases (4%). Concerning proximal repair, four of them (66%) had had a Bentall procedure at the first operation, and concerning distal repair, three of them (50%) had a replacement of the aortic arch (hemi arch replacement in 2, total arch replacement in 1).
2.4. Follow-up
All survivors were included in a routine follow-up program by nuclear magnetic resonance imaging (MRI), to reduce exposure to irradiation of CT-scan [1,7]. The first exam was a CT-scan and was made in-hospital before discharge of the patient, as reference. If no major pathological findings were present, the subsequent MRI was done three months postoperatively. State of the distal false lumen, aortic diameter and progression of aortic dilatation determined the further intervals for control: six months during the first year (or less for patients with evident aortic disease or diameters between 50 and 60 mm), 12 months during the next five years, then 24 months.
Aneurysm of aortic arch or thoracic descending aortic aneurysm (TDAA) was defined by a diameter of 60 mm on transversal slides at CT-scan or MRI.
All patients had transthoracic echocardiography yearly.
Clinical follow-up was updated by recent examination, phone contact, and information obtained from primary care physicians and cardiologists.
The indications for replacement of the affected aortic segment were based on that following criteria: transversal aortic diameter exceeding 60 mm, rapid progression of aortic diameter enlargement, symptomatic or ruptured aortic aneurysm.
Follow-up was completed for 146 patients (99.3%). One patient became untraceable two months after the initial operation.
Total follow-up was 626 patient-years, with a mean follow-up time of 4.45 years (two months to 11.5 years).
2.5. Statistical analysis
Data were analyzed with a commercially available package (SPSS for Windows, rel 11.5, 2002; SPSS Inc, Chicago, IL, USA). Student's t-test was used to compare continuous variables (values were expressed as means and standard deviation) between the studied groups of patients. Categorical variables were compared by 2-test or Fisher's exact test when appropriate. The effect of prognostic factors on both reoperations and cardiovascular mortality were studied computing Kaplan–Meier estimates, and curves were compared using the log-rank test. Logistic regression models were used to estimate the adjusted probabilities of late patency of the false lumen and post-dissection aortic aneurysm. Cox proportional hazards models were used to estimate the adjusted effect of prognostic factors on reoperations. All tests were two-tailed and P-values <0.05 were considered as statistically significant. Multivariate analysis was performed with a forward stepwise approach with P=0.10 as the threshold for entering or removing variables.
3. Results
3.1. Time-related survival
Overall survival estimates after initial operation (in-hospital mortality excluded) were 96%, 80% and 65% at 1, 5, and 10 years, respectively (Fig. 1).
During the follow-up period, 26 patients died (18%). Causes of late death are listed in Table 3.
3.2. Persistent patent distal false lumen
A patent distal false lumen was observed in 101 cases (69%). Thirty-nine patients (26%) were on long-term oral anticoagulant treatment.
Univariate analysis revealed that older age (more than 70 years old, odds ratio (OR)=10.16, Confidence Interval (CI)= 2.48–58.18) and valve-sparing aortic root reconstruction (OR=3.58, CI=1.34–9.62) were significant predictive factors for thrombosis of the distal false lumen; and that younger age (<50 years old, OR=5.11, CI=1.35–28.41), De Bakey type III retrograde dissections (OR=23.33, CI=3.69–171.42), Bentall procedure (OR=0.17, CI=0.03–0.62), and long-term oral anticoagulation (OR=0.31, CI=0.10–0.84) were significant risk factors for patency of the distal false lumen.
Multivariate proportional hazard regression analysis showed that age of 70 years, and David or Yacoub procedures were significant predictive factors for thrombosis of the distal false lumen (Table 4).
3.3. Distal aneurysmal evolution
Eleven patients (8%) developed aneurysmal dilatation of the distal aorta: 3 involved the aortic arch, and 8 involved the aortic arch and the thoracic descending aorta.
All the patients who developed dissecting aneurysm had a patent distal false lumen.
Patients who developed distal aortic dilatation were younger (mean age 54 years vs. 61 years), but the difference was not statistically significant (P=0.08). Marfan syndrome was a predictive factor of distal aorta dilatation (P=0.09).
3.4. Reoperations on distal aorta
Eight patients (5%) underwent 10 reoperations on the distal aorta. The secondary procedures performed are shown in Table 5. Mean interval of first reoperation on the distal aorta was 4.7±2.8 years after initial operation. One patient with Marfan syndrome who had had one endoprosthesis for a TDAA at the 2nd procedure underwent a third procedure for an aortic arch aneurysm (3 endoprostheses after transposition of the supra aortic trunks) and a fourth procedure for a type 3 endoleak in the aortic arch (2 more endoprostheses). Univariate analysis revealed that only Marfan syndrome was a significant risk factor for distal reoperations (P=0.05). Multivariate proportional hazard regression analysis revealed that Marfan syndrome was associated with distal reoperations (relative risk=4.69, P=0.07). Long-term oral anticoagulation was not an independent risk factor for distal reoperations. There was no in-hospital, paraplegia or late deaths in these ten reoperations. Actuarial estimates freedom from reoperations on the distal aorta was 98%, 96% and 69% at 1, 5 and 10 years, respectively (Fig. 2).
4. Discussion
4.1. Survival
Despite technical improvements in emergency operations for acute type A aortic dissection, in preoperative and postoperative management, in-hospital mortality rate is still catastrophic, around 15 to 30%. A significant late mortality rate exists that depends on persistent risk factors and on persistent patent distal false lumen and its evolution. Long-term survival estimates at 10 years (in-hospital mortality included) range between 30% and 60% [8]. Our long-term results seem comparable and acceptable.
4.2. Evolution of residual false lumen
The reported incidence of persistent patent distal false lumen remains high, between 75% and 100% [9]. Like another study [8], we couldn't find a relation between the use of circulatory arrest with ‘open-distal’ anastomoses and the evolution of the distal false lumen, but in the earlier years we used this technique in all patients, to examine aortic arch, excise the segment of the aorta containing the intimal tear when it originated or extended into the aortic arch or proximal descending thoracic aorta and resect the aortic cross-clamping site.
Comparing to another report [8], the rate of patients who had had a composite graft replacement with the modified Bentall technique in this study is higher (22%). The Cleveland experience [10], comparing surgical repair of ascending aortic aneurysms and dissections, concluded that composite graft replacement must be avoided if possible in the treatment of dissections because late survival of these patients was not favorable. In fact, in our study, the modified Bentall procedure was a significant risk factor for patency of the false lumen, probably because of long-term oral anticoagulation needed. Moreover, most of the patients on long-term regimen of oral anticoagulant treatment (whatever the reason) kept a patent false lumen. In comparison, patients who had valve-sparing aortic root reconstruction, and didn't need anticoagulants, had significantly more thrombosis of their false lumen. The indication for using this technique in acute aortic dissection remains a subject of debate, because it is longer than supracommissural aortic replacement or Bentall procedure, but some studies reported good intermediate-term and long-term [11] results concerning aortic valve competence with this technique in acute dissections, even with Marfan syndrome, but they didn't analyze long-term evolution of the distal false lumen.
4.3. Distal reoperations
In our study, all the patients who developed an aneurysmal dilatation of the distal aorta had a patent false lumen, confirming the results of a previous report in our institution [7]. Dilatation may lead to rupture, known to be the most common cause of late death after surgical repair of acute aortic dissection [2], especially when the diameter reaches 60 mm [12]. The Stanford experience showed that replacement of the aorta in symptomatic or expanding dissecting aneurysms improved long-term survival. In our institution, as previously reported [7,13], close follow-up by CT-scan or MRI allowed an early diagnosis of aortic dilatation and thus, an elective repair of dissecting aneurysms. Progressively we attempt, in elective indications such as emergencies, whenever it is anatomically possible or helped by previous transposition of the supraaortic trunks, to treat these TDAA and also aortic arch aneurysms with combined endovascular and surgical treatments, believing that it could lower in-hospital mortality and paraplegia observed in exclusive surgical treatment of these lesions (5% to 26%, and 7% to 36%, respectively) [14], with acceptable intermediate-term results [15]. In fact, neither death nor paraplegia occurred in our study after the ten reoperations on distal aorta. In all patients treated by endoprosthesis, false lumen thrombosed and aortic diameters reduced. However, long-term durability of endovascular treatment of TDAA remains to be demonstrated, and lifelong surveillance remains necessary.
References
Heinemann M, Laas J, Karck M, Borst HG. Thoracic aortic aneurysm after acute type A aortic dissection: necessity for follow-up. Ann Thorac Surg 1990; 49:580–584.
De Bakey ME, McCollum CH, Crawford ES. Dissection and dissecting aneurysms of the aorta: twenty-year follow-up of five hundred and twenty-seven patients treated surgically. Surgery 1982; 92:1118–1133.
Dinsmore RE, Willerson JT, Buckley MJ. Dissecting aneurysm of the aorta. Aortogrophic features affecting prognosis. Radiology 1972; 105:567–572.
Nashef SA, Roques F, Michel P, Gauducheau E, Lemeshow S, Salamon R. European system for cardiac operative risk evaluation (EuroSCORE). Eur J Cardiothorac Surg Jul 1999; 16:9–13.
David TE, Feindel CM. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovasc Surg 1992; 103:617–622.
Yacoub MH, Gehle P, Chandrasekaran V, Birks EJ, Child A, Radley-Smith R. Late results of a valve-preserving operation in patients with aneuryms of the ascending aorta and root. J Thorac Cardiovasc Surg 1998; 115:1080–1090.
Gaubert JY, Moulin G, Mesana T, Chagnaud C, Caus T, Delannoy L, Blin D, Bartoli JM, Kasbarian M. Type A dissection of the thoracic aorta: use of MR imaging for long-term follow-up. Radiology 1995; 196:363–369.
Kirsch M, Soustelle C, Houl R, Hillion ML, Loisance D. Risk factor analysis for proximal and distal reoperations after surgery for acute type A aortic dissection. J Thorac Cardiovasc Surg 2002; 123:318–325.
Yamaguchi T, Guthaner DF, Wexler L. Natural history of the false channel of type A aortic dissection after surgical repair: CT study. Radiology 1989; 170:743–747.
Lytle BW, Mahfood SS, Cosgrove DM, Loop FD. Replacement of the ascending aorta: early and late results. J Thorac Cardiovasc Surg 1990; 99:651–658.
Kallenbach K, Oelze T, Salcher R, Hagl C, Karck M, Leyh RG, Haverich A. Evolving strategies for treatment of acute aortic dissection type A. Circulation 2004; 110:suppl_IIII-243–II-249.
Pressler VM, McNamara JJ. Thoracic aortic aneurysm. Natural history and treatment. J Thorac Cardiovasc Surg 1980; 79:489–498.
Mesana TG, Caus T, Gaubert JY, Collart F, Ayari R, Bartoli JM, Moulin G, Monties JR. Late complications after prosthetic replacement of the ascending aorta: what did we learn from routine magnetic resonance imaging follow-up. Eur J Cardiothorac Surg 2000; 18:313–320.
Borst HG, Jurmann M, Bühner B, Laas J. Risk of replacement of descending aorta with a standarized left heart bypass technique. J Thorac Cardiovasc Surg 1994; 107:126–133.
Najibi S, Terramani TT, Weiss VJ, Mac Donald J, Lin PH, Redd DC, Martin LG, Chaikof EL, Lumsden AB. Endoluminal versus open treatment of descending thoracic aortic aneurysms. J Vasc Surg 2002; 36:732–737.(Vlad Gariboldia,, Dominique Grisolia, Fr)
b LERTIM, Medicine Faculty, Marseille, France
Presented at the Aortic Surgery Symposium X, 27–28 April 2006, New York.
Abstract
The aim was to evaluate long-term outcomes after surgical treatment of acute type A dissection. Between 1993 and 2004, 199 consecutive patients were operated on for acute type A dissection. All survivors were included in an MRI follow-up program. Follow-up time averaged 4.45 years. Overall survival was 96%, 80% and 65% at 1, 5 and 10 years. The false lumen remained patent in 101 cases (69%). Predicitve factors for thrombosis of the false lumen were age >70 years old and valve-sparing aortic root reconstruction. Significant risk factors for patency of the distal false lumen were age <50 years old, De Bakey type III retrograde dissections, Bentall procedure and long-term anticoagulation. Freedom from reoperation was 98%, 96% and 69% at 1, 5 and 10 years. Eight patients required reoperations for dilatation of distal aorta at 4.7±2.8 years after the first operation. Reoperations consisted of combined surgical and endovascular procedures, without in-hospital or late deaths. Close MRI follow-up demonstrated that aortic false lumen remained patent in a majority of cases. Surgical reconstruction needing long-term anticoagulation must be avoided when possible to decrease patency of the false lumen. However, late reoperations are infrequent and can be treated with a low risk by using endovascular procedures.
Key Words: Aortic dissection; Magnetic resonance imaging; Reoperation
1. Introduction
The aim of surgical management of acute type A aortic dissection is to prevent death by rupture of the ascending aorta [1]. Because of the extent of the disease to the entire aorta, most surviving patients continue to have a patent distal false lumen [1], potentially leading to aneurysmal evolution and its complications, especially the rupture, that is the first cause of late death [2]. It has been recognized that the long-term prognosis of the patients with thrombosed false lumen is superior to that of those with patent false lumen [3]. The following study was undertaken to evaluate long-term outcomes and significant risk factors for patency of the false lumen, dissecting aneurysm evolution and reoperations after surgical treatment of acute Stanford type A dissection.
2. Material and methods
2.1. Patients
Between January 1993 and December 2004, a total of 199 consecutive patients underwent emergency surgical repair for spontaneously occurring acute Stanford type A aortic dissection in the Department of Adult Cardiac Surgery at Timone Hospital, Marseille, France.
One hundred and forty-seven patients were discharged from the hospital. There were 112 men (76%) and 35 women (24%), and their mean age was 60.6±13 years (range 30–88).
Demographics and clinical data are shown in Table 1. Mean additive EuroSCORE [4] was 9.3±2.3.
Data were collected from September to December 2004.
2.2. Anatomy
According to De Bakey classification [3], 106 patients (72%) were type I, 24 patients (16%) were type II and 17 patients (12%) were type III with retrograde extension. Locations of the primary intimal tear are listed in Table 2.
2.3. Surgical procedures
Cardiopulmonary bypass was established by median sternotomy after retrograde femoral artery cannulation. Cardiac arrest was obtained by retrograde administration of cold crystalloid cardioplegia into the coronary sinus, sometimes completed by antegrade administration in the coronary ostia. After aortic cross clamping the ascending aorta was opened, and the aortic root was inspected and repaired during systemic cooling.
Concerning the proximal aortic repair, replacement of the supracoronary ascending aorta and aortic valve resuspension was performed in 80 cases (54%), composite graft replacement of the aortic valve, sinuses, and ascending aorta with the modified Bentall technique was performed in 32 cases (22%), separate replacement of the supracoronary ascending aorta and aortic valve was performed in four cases (3%), and in 31 patients (21%) the aortic root was replaced and the aortic valve was reimplanted (valve-sparing aortic root reconstruction) according to David [5] in six cases (4%) and according to Yacoub [6] in 25 cases (17%).
Concerning the distal repair, circulatory arrest was used in 89 cases (60%). Deep hypothermic circulatory arrest (DHCA) at 15–20 °C alone was used in 15 cases (17%), associated with antegrade selective cerebral perfusion (ASCP) in 52 cases (58%) or retrograde cerebral perfusion (RCP) in the superior vena cava in 22 cases (25%). This was achieved with a hemi arch replacement in 71 cases (48%) and a total arch replacement in 18 cases (12%). In the remaining 58 patients (40%) the distal anastomoses were made under aortic cross clamping just proximal to the in nominate artery.
Proximal and distal anastomoses were made with 3-0 or 4-0 monofilament sutures reinforced by polytetrafluoroethylene band. Gelatin-resorcinol-formaldehyde (GRF) biologic glue (Colle biologique; Fii, Saint Just Malmont, France) was used in 17 cases (12%), and Tissucol fibrinous glue (Immuno AG; Vienna, Austria) was used in 139 cases (95%).
Marfan syndrome was present in six cases (4%). Concerning proximal repair, four of them (66%) had had a Bentall procedure at the first operation, and concerning distal repair, three of them (50%) had a replacement of the aortic arch (hemi arch replacement in 2, total arch replacement in 1).
2.4. Follow-up
All survivors were included in a routine follow-up program by nuclear magnetic resonance imaging (MRI), to reduce exposure to irradiation of CT-scan [1,7]. The first exam was a CT-scan and was made in-hospital before discharge of the patient, as reference. If no major pathological findings were present, the subsequent MRI was done three months postoperatively. State of the distal false lumen, aortic diameter and progression of aortic dilatation determined the further intervals for control: six months during the first year (or less for patients with evident aortic disease or diameters between 50 and 60 mm), 12 months during the next five years, then 24 months.
Aneurysm of aortic arch or thoracic descending aortic aneurysm (TDAA) was defined by a diameter of 60 mm on transversal slides at CT-scan or MRI.
All patients had transthoracic echocardiography yearly.
Clinical follow-up was updated by recent examination, phone contact, and information obtained from primary care physicians and cardiologists.
The indications for replacement of the affected aortic segment were based on that following criteria: transversal aortic diameter exceeding 60 mm, rapid progression of aortic diameter enlargement, symptomatic or ruptured aortic aneurysm.
Follow-up was completed for 146 patients (99.3%). One patient became untraceable two months after the initial operation.
Total follow-up was 626 patient-years, with a mean follow-up time of 4.45 years (two months to 11.5 years).
2.5. Statistical analysis
Data were analyzed with a commercially available package (SPSS for Windows, rel 11.5, 2002; SPSS Inc, Chicago, IL, USA). Student's t-test was used to compare continuous variables (values were expressed as means and standard deviation) between the studied groups of patients. Categorical variables were compared by 2-test or Fisher's exact test when appropriate. The effect of prognostic factors on both reoperations and cardiovascular mortality were studied computing Kaplan–Meier estimates, and curves were compared using the log-rank test. Logistic regression models were used to estimate the adjusted probabilities of late patency of the false lumen and post-dissection aortic aneurysm. Cox proportional hazards models were used to estimate the adjusted effect of prognostic factors on reoperations. All tests were two-tailed and P-values <0.05 were considered as statistically significant. Multivariate analysis was performed with a forward stepwise approach with P=0.10 as the threshold for entering or removing variables.
3. Results
3.1. Time-related survival
Overall survival estimates after initial operation (in-hospital mortality excluded) were 96%, 80% and 65% at 1, 5, and 10 years, respectively (Fig. 1).
During the follow-up period, 26 patients died (18%). Causes of late death are listed in Table 3.
3.2. Persistent patent distal false lumen
A patent distal false lumen was observed in 101 cases (69%). Thirty-nine patients (26%) were on long-term oral anticoagulant treatment.
Univariate analysis revealed that older age (more than 70 years old, odds ratio (OR)=10.16, Confidence Interval (CI)= 2.48–58.18) and valve-sparing aortic root reconstruction (OR=3.58, CI=1.34–9.62) were significant predictive factors for thrombosis of the distal false lumen; and that younger age (<50 years old, OR=5.11, CI=1.35–28.41), De Bakey type III retrograde dissections (OR=23.33, CI=3.69–171.42), Bentall procedure (OR=0.17, CI=0.03–0.62), and long-term oral anticoagulation (OR=0.31, CI=0.10–0.84) were significant risk factors for patency of the distal false lumen.
Multivariate proportional hazard regression analysis showed that age of 70 years, and David or Yacoub procedures were significant predictive factors for thrombosis of the distal false lumen (Table 4).
3.3. Distal aneurysmal evolution
Eleven patients (8%) developed aneurysmal dilatation of the distal aorta: 3 involved the aortic arch, and 8 involved the aortic arch and the thoracic descending aorta.
All the patients who developed dissecting aneurysm had a patent distal false lumen.
Patients who developed distal aortic dilatation were younger (mean age 54 years vs. 61 years), but the difference was not statistically significant (P=0.08). Marfan syndrome was a predictive factor of distal aorta dilatation (P=0.09).
3.4. Reoperations on distal aorta
Eight patients (5%) underwent 10 reoperations on the distal aorta. The secondary procedures performed are shown in Table 5. Mean interval of first reoperation on the distal aorta was 4.7±2.8 years after initial operation. One patient with Marfan syndrome who had had one endoprosthesis for a TDAA at the 2nd procedure underwent a third procedure for an aortic arch aneurysm (3 endoprostheses after transposition of the supra aortic trunks) and a fourth procedure for a type 3 endoleak in the aortic arch (2 more endoprostheses). Univariate analysis revealed that only Marfan syndrome was a significant risk factor for distal reoperations (P=0.05). Multivariate proportional hazard regression analysis revealed that Marfan syndrome was associated with distal reoperations (relative risk=4.69, P=0.07). Long-term oral anticoagulation was not an independent risk factor for distal reoperations. There was no in-hospital, paraplegia or late deaths in these ten reoperations. Actuarial estimates freedom from reoperations on the distal aorta was 98%, 96% and 69% at 1, 5 and 10 years, respectively (Fig. 2).
4. Discussion
4.1. Survival
Despite technical improvements in emergency operations for acute type A aortic dissection, in preoperative and postoperative management, in-hospital mortality rate is still catastrophic, around 15 to 30%. A significant late mortality rate exists that depends on persistent risk factors and on persistent patent distal false lumen and its evolution. Long-term survival estimates at 10 years (in-hospital mortality included) range between 30% and 60% [8]. Our long-term results seem comparable and acceptable.
4.2. Evolution of residual false lumen
The reported incidence of persistent patent distal false lumen remains high, between 75% and 100% [9]. Like another study [8], we couldn't find a relation between the use of circulatory arrest with ‘open-distal’ anastomoses and the evolution of the distal false lumen, but in the earlier years we used this technique in all patients, to examine aortic arch, excise the segment of the aorta containing the intimal tear when it originated or extended into the aortic arch or proximal descending thoracic aorta and resect the aortic cross-clamping site.
Comparing to another report [8], the rate of patients who had had a composite graft replacement with the modified Bentall technique in this study is higher (22%). The Cleveland experience [10], comparing surgical repair of ascending aortic aneurysms and dissections, concluded that composite graft replacement must be avoided if possible in the treatment of dissections because late survival of these patients was not favorable. In fact, in our study, the modified Bentall procedure was a significant risk factor for patency of the false lumen, probably because of long-term oral anticoagulation needed. Moreover, most of the patients on long-term regimen of oral anticoagulant treatment (whatever the reason) kept a patent false lumen. In comparison, patients who had valve-sparing aortic root reconstruction, and didn't need anticoagulants, had significantly more thrombosis of their false lumen. The indication for using this technique in acute aortic dissection remains a subject of debate, because it is longer than supracommissural aortic replacement or Bentall procedure, but some studies reported good intermediate-term and long-term [11] results concerning aortic valve competence with this technique in acute dissections, even with Marfan syndrome, but they didn't analyze long-term evolution of the distal false lumen.
4.3. Distal reoperations
In our study, all the patients who developed an aneurysmal dilatation of the distal aorta had a patent false lumen, confirming the results of a previous report in our institution [7]. Dilatation may lead to rupture, known to be the most common cause of late death after surgical repair of acute aortic dissection [2], especially when the diameter reaches 60 mm [12]. The Stanford experience showed that replacement of the aorta in symptomatic or expanding dissecting aneurysms improved long-term survival. In our institution, as previously reported [7,13], close follow-up by CT-scan or MRI allowed an early diagnosis of aortic dilatation and thus, an elective repair of dissecting aneurysms. Progressively we attempt, in elective indications such as emergencies, whenever it is anatomically possible or helped by previous transposition of the supraaortic trunks, to treat these TDAA and also aortic arch aneurysms with combined endovascular and surgical treatments, believing that it could lower in-hospital mortality and paraplegia observed in exclusive surgical treatment of these lesions (5% to 26%, and 7% to 36%, respectively) [14], with acceptable intermediate-term results [15]. In fact, neither death nor paraplegia occurred in our study after the ten reoperations on distal aorta. In all patients treated by endoprosthesis, false lumen thrombosed and aortic diameters reduced. However, long-term durability of endovascular treatment of TDAA remains to be demonstrated, and lifelong surveillance remains necessary.
References
Heinemann M, Laas J, Karck M, Borst HG. Thoracic aortic aneurysm after acute type A aortic dissection: necessity for follow-up. Ann Thorac Surg 1990; 49:580–584.
De Bakey ME, McCollum CH, Crawford ES. Dissection and dissecting aneurysms of the aorta: twenty-year follow-up of five hundred and twenty-seven patients treated surgically. Surgery 1982; 92:1118–1133.
Dinsmore RE, Willerson JT, Buckley MJ. Dissecting aneurysm of the aorta. Aortogrophic features affecting prognosis. Radiology 1972; 105:567–572.
Nashef SA, Roques F, Michel P, Gauducheau E, Lemeshow S, Salamon R. European system for cardiac operative risk evaluation (EuroSCORE). Eur J Cardiothorac Surg Jul 1999; 16:9–13.
David TE, Feindel CM. An aortic valve-sparing operation for patients with aortic incompetence and aneurysm of the ascending aorta. J Thorac Cardiovasc Surg 1992; 103:617–622.
Yacoub MH, Gehle P, Chandrasekaran V, Birks EJ, Child A, Radley-Smith R. Late results of a valve-preserving operation in patients with aneuryms of the ascending aorta and root. J Thorac Cardiovasc Surg 1998; 115:1080–1090.
Gaubert JY, Moulin G, Mesana T, Chagnaud C, Caus T, Delannoy L, Blin D, Bartoli JM, Kasbarian M. Type A dissection of the thoracic aorta: use of MR imaging for long-term follow-up. Radiology 1995; 196:363–369.
Kirsch M, Soustelle C, Houl R, Hillion ML, Loisance D. Risk factor analysis for proximal and distal reoperations after surgery for acute type A aortic dissection. J Thorac Cardiovasc Surg 2002; 123:318–325.
Yamaguchi T, Guthaner DF, Wexler L. Natural history of the false channel of type A aortic dissection after surgical repair: CT study. Radiology 1989; 170:743–747.
Lytle BW, Mahfood SS, Cosgrove DM, Loop FD. Replacement of the ascending aorta: early and late results. J Thorac Cardiovasc Surg 1990; 99:651–658.
Kallenbach K, Oelze T, Salcher R, Hagl C, Karck M, Leyh RG, Haverich A. Evolving strategies for treatment of acute aortic dissection type A. Circulation 2004; 110:suppl_IIII-243–II-249.
Pressler VM, McNamara JJ. Thoracic aortic aneurysm. Natural history and treatment. J Thorac Cardiovasc Surg 1980; 79:489–498.
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