Long-Term Results After Repair of Type A Acute Aortic Dissection According to False Lumen Patency

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1 Long-Term Results After Repair of Type A Acute Aortic Dissection According to False Lumen Patency Khalil Fattouch, MD, PhD, Roberta Sampognaro, MD, Emiliano Navarra, MD, Marco Caruso, MD, PhD, Calogera Pisano, MD, Giuseppe Coppola, MD, PhD, Giuseppe Speziale, MD, and Giovanni Ruvolo, MD Department of Cardiac Surgery, University of Palermo, Palermo, Italy Background. Late survival and freedom from retreatment on the descending aorta was evaluated after ascending aortic repair for type A acute aortic dissection (TAAAD). Methods. Between March 1992 and January 2006, 189 TAAAD patients (mean age, 52 11; range, 17 to 83 years) were included; of these, 58 had a patent false lumen, and 49 had Marfan syndrome. The descending aorta was evaluated postoperatively with computed tomography (CT). Late outcomes were assessed by Cox regression analysis and actuarial survival and freedom from retreatment by the Kaplan-Meier method. Mean follow-up was months. Results. There were 38 (20%) late deaths. At 10 years, survival was 89.8% 2.1% for patients with an occluded false lumen and 59.8% 3.5% for patients with a patent false lumen (p 0.001), and freedom from retreatment on the descending aorta was 94.2% 3.1% for an occluded false lumen and 63.7% 2.6% for a patent false lumen (p < ). Descending aortic rupture (p 0.002) and a patent false lumen (p 0.001) were predictors for late death. Patent false lumen (p ), Marfan syndrome (p 0.03), and descending aortic diameter 4.5 cm or larger (p 0.002) were predictors for retreatment. Conclusions. A patent false lumen was a predictor for late death and retreatment on the descending aorta. Marfan syndrome and aortic size exceeding 4.5 cm were predictors for late retreatment. These patients require very close follow-up and a plan for retreatment on the descending aorta to prevent sudden rupture and late death. (Ann Thorac Surg 2009;88: ) 2009 by The Society of Thoracic Surgeons Type A acute aortic dissection (TAAAD) represents a cardiovascular emergency event that requires immediate surgical treatment to reduce its life-threatening complications. In the largest review of untreated patients with TAAAD, the mortality rate was about 50% within the first 48 hours [1, 2]. A mathematical model has been developed to predict 30-day mortality to determine a cutoff for surgical intervention [3], but today, there is a general agreement that the operation must be performed as soon as possible, before complications occur or their effects become irreversible. Although the results from emergency surgical treatment are continuing to improve as a result of better surgical techniques and advances in perioperative diagnosis and care, surviving the initial operation is not a guarantee against subsequent aortic events because much of the descending thoracic aorta remains dissected. The postoperative fate of the descending aorta and false lumen is still unclear. The false lumen can undergo thrombosis or remain patent postoperatively, and the descending aorta can dilate progressively, leading to Accepted for publication June 19, Address correspondence to Dr Fattouch, University of Palermo, Cardiac Surgery Department, Via Liborio Giuffré, 5, Palermo, 90127, Italy; khalilfattouch@hotmail.com. rupture or reoperation, or both. Although early and late results of repair of TAAAD have been widely analyzed [4 13], few studies have investigated the evolution of the false lumen and the incidence of descending aorticrelated events. The aim of our study was to evaluate the long-term survival and freedom from retreatment on the descending aorta, defined as reoperation or endovascular stenting, in 189 patients who survived an operation for TAAAD. Material and Methods This study was approved by the local Ethics Committee of the University of Palermo and by the Ethics Committee of the University of Rome La Sapienza. All patients signed an informed consent. Patients and Study Design Between March 1992 and January 2006, 224 consecutive patients were operated on for TAAAD by a two surgeons (G. R., K. F.) at the University of Rome La Sapienza (before 2002) and subsequently at the University of Palermo (after 2003). The false lumen in all patients extended to the entire aorta from the ascending aorta to the iliac arteries. The incidence of in-hospital ( by The Society of Thoracic Surgeons /09/$36.00 Published by Elsevier Inc doi: /j.athoracsur

2 Ann Thorac Surg FATTOUCH ET AL 2009;88: FALSE LUMEN PATENCY AFTER REPAIR OF TYPE A DISSECTION 1245 day) deaths was 15.6% (35 patients). Follow-up was maintained on the 189 survivors (121 men, 68 women). Data were collected from the hospital computerized patient registry. Mean age was years (range, 17 Table 1. Demographics and Clinical Patients Characteristics Variables No. (%) or Mean SD (N 189) 14 (7.4) Male sex 148 (78.3) Age, y Hypertension 158 (81.5) Marfan syndrome 49 (26) Redo 15 (8) Neurologic deficit 9 (4.7) Anuria 16 (8.4) Aortic rupture 11 (5.8) Shock 15 (8) Acute myocardial infarction 3 (1.5) Aortic regurgitation 3 82 (43.3) Cardiac tamponade 21 (11) Malperfusion syndrome at presentation a Surgical procedures AAR 133 (70.3) AAR Arch 32 (17) AAR hemi-arch 24 (12.7) Bentall 34 (18) Aortic valve replacement 28 (14.8) Aortic valve resuspension 30 (15.8) Aortic valve-sparing 31 (16.4) CABG 11 (5.8) Operative variables CPB time, min Aortic cross-clamp time, min Circulatory arrest time, min Cerebral protection Antegrade perfusion 68 (36) Retrograde perfusion 63 (33.3) Only DHCA 58 (30.6) Complications Renal failure b 11 (5.8) Respiratory insufficiency c 15 (8) Low cardiac output 8 (4.2) Temporary neurologic injury 14 (7.4) Reoperation for bleeding 12 (6.3) Post-op descending aorta size, d cm (17) 3.5 to (33.3) (49.7) a Absent peripheral pulse with appropriate ischemic symptomatology, absence of renal opacification, or presence of intestinal ischemia documented at computed tomography scan. b Renal failure requiring dialysis. c Respiratory insufficiency need prolonged mechanical ventilation with or without tracheostomy. d The initial aortic size measured at hospital discharge after the first operation. AAR ascending aortic replacement; CABG coronary artery bypass grafting; CPB cardiopulmonary bypass; DHCA deep hypothermic circulatory arrest; SD standard deviation. Fig 1. In this short-axial computed tomography image, measurement of the diameter of the descending aorta (AB) was performed at the largest short-axial diameter of the outer contour of the aorta perpendicular to the dissection line. The dotted line is considered as dissection line. to 83 years). Demographics and perioperative clinical characteristics are summarized in Table 1. All patients underwent their first operation as an emergency procedure. The time from onset of symptoms to intervention was hours (range, 3 to 22 hours). Computed tomography (CT) scans were performed preoperatively on all patients to confirm diagnosis. Transesophageal echocardiography (TEE) was performed on all patients in the operating room to localize the intimal tear and to assess the aortic valve and the left ventricular function. Previous aortic valve operations had been done in 15 patients (8%), and 49 patients had Marfan syndrome. Further in-hospital treatment was required in 14 patients with early postoperative malperfusion complications. All patients underwent CT control at hospital discharge to evaluate the descending thoracic aorta. The false lumen was evaluated, and the short-axial CT images were used to measure the diameter of the descending aorta measured at different levels for each patient. Sizing was performed at the largest short-axial diameter of the outer contour of the aorta, perpendicular to the dissection line to avoid measurements of the elliptical aortic shape (Fig 1). Measurements were taken at the level of the descending aorta just after the origin of the left subclavian artery and at the level of diaphragmatic hiatus. An average between the 2 measures was considered as absolute value. Surgical Techniques All patients underwent standard longitudinal median sternotomy and cardiopulmonary bypass (CPB), with right atrial and femoral cannulation in 142 patients or axillary artery cannulation in 47. Cerebral protection was

3 1246 FATTOUCH ET AL Ann Thorac Surg FALSE LUMEN PATENCY AFTER REPAIR OF TYPE A DISSECTION 2009;88: Table 2. Causes of Late Death Causes No. (%) (N 189) Descending aortic rupture 9 (4.7) Renal failure 6 (3.1) Related to anticoagulant 3 (1.5) Cardiac failure 12 (6.3) Neurological injury 2 (1) Re-op on descending aorta 6 (3.1) Total 38 (20) performed with deep hypothermic circulatory arrest (DHCA) alone in 58 patients who had noncomplex anatomy of proximal, with DHCA and retrograde cerebral perfusion in 63, and with DHCA and selective antegrade cerebral perfusion in 68. During the first operation, when the intimal tear was located only in the ascending aorta, we simply replaced it. When the intimal tear was present or extended to the aortic arch, we partially or totally replaced it. Surgical treatment of the aortic valve or root was performed according to their pathology. Details about surgical approach are described in our previous study [11]. Follow-Up Data Clinical outcomes and survival information were obtained from our computerized outcome data collection instrument or by phone or mail contact with patients and referring cardiologists or family physicians. The descending aortic related-events are defined as aortic rupture, repeat operation, or endovascular stenting. At hospital discharge, all patients underwent CT control and we asked them to undergo CT imaging at an interval of 1 year. Postoperative CT images were collected from patients and evaluated by 2 experienced cardiovascular radiologists. A total of 1148 CT images were evaluated (mean of images per patient). The follow-up data were obtained in all patients. Follow-up began on March 2008 and ended in December 2008, with a mean follow-up of months. The closing interval during follow-up was 3 months. Fig 2. Actuarial survival rate for the entire population. Univariate analysis between the in-hospital ( 30 day) mortality and variables (Table 1) were tested using a two-sample t test for quantitative variables or the 2 test for qualitative variables. Interval-scaled variables such as age, CPB time, cross-clamp time, circulatory arrest time, and descending aortic size were analyzed by simple univariate linear regression test. Variables that were statistically significant in the univariate analysis were put into a multivariate logistic regression model. A Cox proportional hazards regression model was used to evaluate late outcomes. Where appropriate, hazard ratios (HR) and odds ratios (OR) were calculated with 95% confidence intervals (CI). Actuarial survival and other time-related events were analyzed with the Kaplan- Meier method. Log-rank test was used to compare statistical significance level. Values of p 0.05 were considered statistically significant. The SPSS software (SPSS Inc, Chicago, IL) was used. Results Hospital Mortality The in-hospital ( 30-day) mortality rate was 15.6% (35 patients). The cause of in-hospital death was multiorgan Statistical Analysis Numeric values are expressed as mean standard deviation. The frequency ratios are given as percentages. Table 3. Results of Cox Regression Analysis in All Patients Variables HR (95% CI) p Value Late death DA rupture 8.2 ( ) Patent false lumen 11.2 ( ) Retreatment on DA Patent false lumen 15.2 ( ) Marfan syndrome 3.5 ( ) 0.03 DA diameter 4.5 cm 5.8 ( ) CI confidence interval; DA descending aorta; HR hazards ratio. Fig 3. Actuarial survival rates are shown for patients with patent false lumen (solid line) vs occluded (dashed line) false lumen.

4 Ann Thorac Surg FATTOUCH ET AL 2009;88: FALSE LUMEN PATENCY AFTER REPAIR OF TYPE A DISSECTION 1247 Fig 4. Actuarial survival rates are shown for patients with Marfan syndrome (solid line) vs those without Marfan (dashed line) syndrome. failure in 8 patients, pulmonary causes in 7, low cardiac output in 6, bleeding in 5, stroke in 5, and sepsis in 4. Multiple logistic regression analysis showed that preoperative aortic rupture (OR, 4.6; 95% CI, 0.8 to 9.4; p 0.03), CPB time exceeding 210 minutes (OR, 11.5; 95% CI, 3.7 to 38.2; p 0.001), and reexploration for bleeding (OR, 9.6; 95% CI, 2.3 to 29.4; p 0.005) were predictors for in-hospital mortality. Late Death There were 38 (20%) late deaths, and the causes are listed in Table 2. By Cox regression analysis, descending aortic rupture (HR, 8.2, 95% CI, 1.8 to 25.6, p 0.002) and false lumen patency (HR, 11.2, CI, 3.9 to 36.8, p 0.001) emerged as predictors for late death (Table 3). The actuarial survival rate for the entire population was 97.7% 1.2% at 1 year, 88.2% 2.4% at 5 years, and 79.8% 2.8% at 10 years (Fig 2). The overall rate of false lumen patency was 31%. Late death was observed in 24 patients (41.3%) with a patent false lumen during the follow-up period. The actuarial survival rate for patients with patent and occluded false lumen are shown in Figure 3. Survival rates Table 4. Follow-Up Data Variable False Lumen, No. (%) Patent (n 58) Occluded (n 131) p Value Total descending aorta 28 (48.2) 6 (4.5) retreatment Reoperation 17 (29.3) 2 (1.5) Stenting 11 (19) 4 (3) Rupture 9 (15.5) 2 (1.5) Proximal aorta Reoperation 3 (5) 6 (4.5) 0.66 Rupture 1 (1.7) 1 (0.8) 0.32 Pseudoaneurysm at 2 (3.4) 3 (2.2) 0.61 anastomoses Total death 24 (41.3) 14 (10.5) 0.01 Fig 5. Freedom from endovascular or surgical retreatment on the descending aorta according to whether the false lumen was occluded (dashed line) or patent (solid line). for patients with an occluded false lumen were 100% at 1 year, 96.2% 1.2% at 5 years, and 89.8% 2.1% at 10 years. Survival rates for patients with a patent false lumen were 95.1% 1.6% at 1 year, 85.2% 2.2% at 5 years, and 59.8% 4.5% at 10 years. A statistically significant difference was found between the 2 groups (p 0.001). Eight (16.5%) deaths occurred in patients with Marfan syndrome during follow-up. The survival rates for Marfan and non-marfan patients are shown in Figure 4. The survival rate for patients with Marfan syndrome was 98.2% 1.3% at 1 year, 91.3% 2.1% at 5 years, and 82.5% 2.4% at 10 years; the survival rate for non- Marfan patients was 97.8% 1.1% at 1 year, 86.6% 1.8% at 5 years, and 79.2% 3.5% at 10 years. No statistically significant difference was found between the two groups (p 0.12). Repeat Operations on the Ascending Aorta During follow-up, 43 patients (22.7%) underwent repeat treatment on the entire aorta. The aortic root was replaced with composite graft in 9 patients (4.7%). Causes of ascending aortic reoperation were pseudoaneurysm at the proximal suture line in 5 patients, rupture in 2, and aortic root dilation with severe valve insufficiency in 2. All patients survived the second operation. Descending Aortic Rupture Descending aortic rupture was found in 11 patients (5.8%) at follow-up. A statistically significant difference was observed between the 9 patients with a patent false lumen vs 2 patients with an occluded false lumen (p 0.001; Table 4). Among them, 4 patients died of preoperative rupture, and 7 underwent surgical retreatment. In-hospital deaths occurred in 3 patients, and 2 deaths occurred after hospital discharge from cardiac and renal failure. The difference between Marfan vs non-marfan patients was not statistically significant (p 0.21).

5 1248 FATTOUCH ET AL Ann Thorac Surg FALSE LUMEN PATENCY AFTER REPAIR OF TYPE A DISSECTION 2009;88: Marfan patients with an occluded false lumen ( mm; p 0.001). From these data we deduced that patients with a patent false lumen and Marfan syndrome experience a high rate of aortic growth. Fig 6. Freedom from endovascular or surgical retreatment on descending aorta according to the presence (dashed line) or absence (solid line) of Marfan syndrome. Retreatment on Descending Aorta A repeat operation on the descending aorta was performed in 19 patients (10%) and endovascular stenting in 15 (8%; Table 4). The causes of retreatment on the descending aorta were aortic rupture, progressive aortic dilation with a patent false lumen, and aortic diameter exceeding 6 cm. The mean diameter of the descending aorta at the second operation was cm. For the patients with an occluded false lumen, freedom from retreatment on the descending aorta was 99% 0.3% at 1 year, 97.2% 1.3% at 5 years, and 94.2% 3.1% at 10 years. For the patients with a patent false lumen, freedom from retreatment was 89.3% 2.3% at 1 year, 72.2% 3.1% at 5 years, and 63.7% 2.6% at 10 years (Fig 5). A statistically significant difference was found between the 2 groups (p ). For the subgroup of patients with Marfan syndrome, freedom from retreatment on the descending aorta was 97.2% 1.2% at 1 year, 84.3% 2.1% at 5 years, and 74.5% 2.6% at 10 years. Freedom from retreatment for non-marfan patients was 98.2% 0.8% at 1 year, 89.5% 1.6% at 5 years, and 86.4% 2.3% at 10 years (Fig 6). Statistical analysis showed a significant difference between the 2 groups (p 0.03). During the follow-up period, 22 Marfan patients (15.7%) and 12 non-marfan patients (24.5%) underwent retreatment. A patent false lumen was present in 16 Marfan patients (32.6%) and in 42 non-marfan patients (30%; p 0.12). Among the 16 patients with Marfan syndrome and a patent false lumen, 12 (75%) underwent retreatment on the descending aorta. Aortic Growth Rate The yearly aortic growth rate was and mm in patients with patent and occluded false lumen, respectively (p 0.001), and and mm (p 0.02), respectively, in patients with and without Marfan syndrome. Patients with Marfan syndrome and a patent false lumen experienced a higher incidence of yearly aortic growth rate ( mm) with respect to Comment Aortic dissection is the most common catastrophic event affecting the aorta. Because the prognosis of this disease is very poor without immediate surgical treatment, patients with TAAAD require emergency operations. Although the operation remains challenging, outcomes have been improved remarkably during the last decade due to earlier diagnosis, prompt surgical therapy, advances in management of DHCA, and increased surgical experience. Despite many recent improvements in the care of patients with TAAAD, the in-hospital mortality rate remains between 10% and 30% [5 14]. The recently published data from the International Registry of Acute Aortic Dissection reports an in-hospital mortality rate of 26% after operations for TAAAD [15]. The dissecting process occurs suddenly and evolves progressively, leading to extension of the false lumen to the entire aorta. Goal of the first surgical approach consists in resection of the intimal tear and replacement of the ascending aorta with or without extension to the aortic arch. Unfortunately, surviving the first operation does not guarantee freedom from subsequent aortic events, because in many cases, the distal intimal tear cannot be resected and the false lumen frequently remains patent, leading to progressive descending aortic dilation and rupture. Late descending aortic retreatment after first surgical repair of TAAAD is relatively common. Several studies have reported an actuarial freedom from aortic reoperations of 55% to 85% at 10 years [5, 6, 8, 14, 16]. Inour study, actuarial freedom from surgical or endovascular retreatment on the descending aorta was 81.3% 3% at 10 years. We found a statistically significant difference between group of patients with a patent false lumen and patients with an occluded false lumen (p ; Fig 5) and between Marfan and non-marfan patients (p 0.03; Fig 6). By Cox regression analysis, the presence of a patent false lumen and Marfan syndrome emerged as predictors for late retreatment on descending aorta (Table 3). The finding that primary size and patency of the false lumen are the dominant factors accelerating aortic expansion is recognized. The influence of false lumen patency in determining faster subsequent growth of a dissected descending aorta has been noted previously [17, 18]. Fattori and colleagues [17] and Halstead and colleagues [18] found the yearly aortic growth rate was maximal in the descending aortic segment and significantly higher in patients with a patent false lumen. The median descending aortic growth rate of 1 mm/y found by Halstead and colleagues is considerably less than the 3.7 mm/y found by Fattori and colleagues, but in the absence of false lumen patency, the growth rate of the descending aorta in both studies was similar at 1.1 mm/y. We think

6 Ann Thorac Surg FATTOUCH ET AL 2009;88: FALSE LUMEN PATENCY AFTER REPAIR OF TYPE A DISSECTION 1249 that the higher overall growth rate reported by Fattori and colleagues reflects a 78% proportion of patients with a patent false lumen vs only 43% in the work by Halstead and colleagues. Moreover, previous studies have shown a 26.5% to 39.4% incidence of false lumen patency in patients with TAAAD after ascending aortic grafting [19, 20]. Akutsu and colleagues [21] found that patency of the false lumen is a strong independent prognostic factor for type B aortic dissection. On the other hand, Tsai and colleagues [22] in a study of 201 patients with type B aortic dissection enrolled in the International Registry found that partial thrombosis of the false lumen, compared with patency, is a significant independent predictor of late death. We observed a patent false lumen in 31% of patients. We found that patency of the false lumen significantly reduces long-term survival (Fig 3). The incidence of late death was significantly higher in the patients with a patent false lumen than in patients with an occluded false lumen (41.3% vs 10.5%; p 0.01; Table 4). Bachet and colleagues [23] showed that the presence of Marfan syndrome favors secondary dilation, but others have not confirmed this observation [17]. In our study, a high percentage of aortic growth rate was observed in patients with Marfan syndrome and in those with a patent false lumen. The presence of Marfan syndrome itself favors further dilation of the descending aorta independently from the presence of a patent false lumen. Immer and colleagues [24] showed that the extent of the TAAAD, with involvement of the supraaortic branches or combined with malperfusion syndrome, or both, the presence of a patent false lumen, and an enlarged downstream aorta seem to be important predictors of secondary dilation. Moreover, a possible role of an enlarged initial downstream aorta on late secondary distal aortic dilation was found by Griepp and colleagues [25]. We observed that a primary diameter of the descending aorta greater than 4.5 cm is a predictor of late retreatment (HR, 5.8; 95% CI, 3.5 to 22.5; p 0.002; Table 3). Among these patients, 38 (40.5%) had a patent false lumen. A high incidence of false lumen patency was found in patients with large descending aorta at first operation. In accordance with previous studies [23, 24], we suggest that patients with a large descending aorta after first operation are more frequently found to have late descending aortic dilation that can lead to aortic retreatment, in particular if the false lumen is patent. Recently, Zierer and colleagues [26] showed that the use of an antihypertensive agent is mandatory to prevent late distal aortic enlargement and prevent aortic rupture in patients have undergone aortic repair for TAAAD. In our experience, even though all patients were receiving antihypertensive therapy with optimal systolic blood pressure control ( 125 mm Hg), a high incidence of distal aortic rupture and retreatment was observed in patients with a patent false lumen. In conclusion, false lumen patency emerged as a predictor for late death and retreatment on the descending aorta. Moreover, Marfan patients with a patent false lumen experienced a higher incidence of retreatment compared with non-marfan patients, without any effect on late death. This is probably because Marfan patients undergo a strict protocol of follow-up imaging, and most operations may be performed in elective status. The incidence of distal aortic rupture that leads to reoperation or death was significantly higher in patients with a patent false lumen (Table 4). The presence of a patent false lumen led to higher yearly aortic growth rate. Furthermore, we think that in patients who undergo aortic repair for TAAAD with a residual false lumen patency, and in particular in patients with Marfan syndrome and in those with primary large descending aorta ( 4.5 cm), despite an optimal long term systolic blood pressure control, close radiographic follow-up is mandatory to prevent further dilatation or sudden aortic rupture and to plan retreatment on the descending aorta in elective status. We thank Prof Raffaele Masciangelo from the Institute of Experimental Medicine and Pathology at the University of Rome La Sapienza for the statistical analysis. References 1. Fuster V, Ip JH. Medical aspects of acute aortic dissection. Semin Thorac Cardiovasc Surg 1991;3: Anagnostopoulus CE, Prabhaker MJS, Kittle CF. Aortic dissections and dissecting aneurysms. Am J Cardiol 1972;30: Centofanti P, Flocco R, Ceresa F, et al. Is surgery always mandatory for type A aortic dissection. Ann Thorac Surg 2006;82: Ruvolo G, Fattouch K, Sinatra R, et al. Factors influencing immediate and long-term results after Button s technique. J Cardiovasc Surg 2002;43: Fann JI, Smith JA, Miller DC, et al. Surgical management of aortic dissection during a 30-year period. Circulation 1995; 92(suppl 2): Ehrlich M, Fang WC, Grabenwoger M, Cartes-Zumelzu F, Wolner E, Havel M. Perioperative risk factors for mortality in patients with acute type A aortic dissection. Circulation 1998;98(suppl 2): Safi HJ, Miller CC 3rd, Reardon MJ, et al. Operation for acute and chronic aortic dissection: recent outcome with regard to neurologic deficit and early death. Ann Thorac Surg 1998;66: Bachet J, Goudot B, Dreyfus GD, et al. Surgery for acute type A dissection. The Hospital Foch experience ( ). Ann Thorac Surg 1999;67: David TE, Armstrong S, Ivanov J, Barnard S. Surgery for acute type A dissection. Ann Thorac Surg 1999;67: Kawahito K, Adachi H, Yamaguchi A, Ino T. Early and late surgical outcomes of acute type A aortic dissection in patients aged 75 years and older. Ann Thorac Surg 2000;70: Sinatra R, Melina G, Pulitani I, Fiorani B, Ruvolo G, Marino B. Emergency operation for acute type A aortic dissection: Neurologic complications and early mortality. Ann Thorac Surg 2001;71: Kawahito K, Adachi H, Yamaguchi A, Ino T. Preoperative risck factors for hospital mortality in acute type A aortic dissection. Ann Thorac Surg 2001;71: Pansini S, Galiardotto PV, Pompei E, et al. Early and late risk factors in surgical treatment of acute type A aortic dissection. Ann Thorac Surg 1998;66: Moon MR, Sundt TM 3rd, Pasque MK, et al. Does the extent of proximal or distal resection influence outcome for type A dissections? Ann Thorac Surg 2001;71: Hagan PG, Nienaber CA, Isselbacher EM, Bruckman D, Karavite DJ, Russman PL, et al. The International Registry of

7 1250 FATTOUCH ET AL Ann Thorac Surg FALSE LUMEN PATENCY AFTER REPAIR OF TYPE A DISSECTION 2009;88: Acute Aortic Dissection (IRAD): new insights into an old disease. JAMA 2000;283: Kirsch M, Soustelle C, Houel R, Hillion Line M, Loisance D. Risk factor analysis for proximal and distal reoperations after surgery for acute type A aortic dissection. J Thoracic Cardiovasc Surg 2002;123: Fattori R, Bacchi-Reggiani L, Bertaccini P, et al. Evolution of aortic dissection after surgical repair. Am J Cardiol 2000;86: Halstead JC, Meier M, Etz C, et al. The fate of the distal aorta after repair of acute type A aortic dissection. J Thoracic and Cardiovasc Surg 2007;133: Ando M, Nakajima N, Adachi S, Nakaya M, Kawashima Y. Simultaneous graft replacement of the ascending aorta and total aortic arch for type A aortic dissection. Ann Thorac Surg 1994;57: Takahara Y, Sudo Y, Mogi K, Nakayama M, Sakurai M. Total aortic arch grafting for acute type A dissection: analysis of residual false lumen. Ann Thorac Surg 2002;73: Akutsu K, Nejima J, Kiuchi K, et al. Effects of the patent false lumen on the long-term outcome of the type B acute aortic dissection. Eur J Cardiothorac Surg 2004;26: Tsai TT, Evangelista A, Nienaber CA, et al. Partial thrombosis of the false lumen in patients with acute Type B aortic dissection. N Engl J Med 2007;357: Bachet JE, Termignon JL, Dreyfus G, et al. Aortic dissection. Prevalence, cause, and results of late reoperation. J Thorac Cardiovasc Surg 1994;108: Immer FF, Hagen U, Berdat PA, Eckstein FS, Carrel TP. Risk factors for secondary dilatation of the aorta after acute type A aortic dissection. Eur J Cardiothoracic Surg 2005;27: Griepp RB, Ergin MA, Galla JD, et al. Natural history of descending thoracic and thoracoabdominal aneurysms. Ann Thorac Surg 1999;67: Zierer A, Voeller RK, Hill KE, Kouchoukos NT, Damiano RJ, Moon MR. Aortic enlargement and late reoperation after repair of acute Type A aortic dissection. Ann Thorac Surg 2007;84: INVITED COMMENTARY We read with great interest the article by Fattouch and colleagues [1] on the long-term fate of the descending aorta after repair of acute type A dissection. This report shows that the natural history of the descending aorta after repaired acute type A dissection is similar to that seen in acute type B dissection, and confirms previous reports from the type B acute dissection literature that 3-year mortality in patients with a patent distal aortic lumen is in the range of 10% to 20% [2, 3]. The authors do not describe partial luminal thrombosis, which has been described in other research as a particularly grave sign [2]. This is a question of considerable importance and its omission from this report is regrettable. Their finding that full thrombosis leads to better long-term prognosis is consistent with Akutsu and colleagues [3], but conflicts with Tsai and colleagues [2], who found complete thrombosis to have a worse outcome than complete patency. The major contribution of this report is the precision of the estimates, due both to the relatively generous sample size and the frequency and completeness of follow-up. The rate at which these aortas expand in close follow-up, nearly 3 mm/yr, is sobering and has implications for timing and mode of treatment. This contribution adds to our conviction that regular follow-up and aggressive lifelong control of hypertension are essential best practices. As intervention strategies continue to develop, studies of the effects of intervention aimed at thrombosing the false lumen are on the horizon. Reports are beginning to appear to the effect that endovascular approaches for distal aortic dissection can facilitate thrombosis of the false lumen [4]. In this context, it is of considerable importance to resolve the question of whether a thrombosed false lumen is better or worse than a patent one. Furthermore, whether accomplishing thrombosis by intraaortic radial force from a stent can decrease enlargement and death over time is far from certain. This question is ideally suited to a randomized trial of stenting versus watchful waiting or open surgery with close follow-up. Charles C. Miller III, PhD Department of Biomedical Sciences Texas Tech University Health Sciences Center Paul L. Foster School of Medicine 5001 El Paso Dr El Paso, TX charles.miller@ttuhsc.edu Anthony L. Estrera, MD Hazim J. Safi, MD Department of Cardiothoracic and Vascular Surgery University of Texas Medical School 6400 Fannin St Houston, TX anthony.l.estrera@uth.tmc.edu; hazim.j.safi@uth.tmc.edu References 1. Fattouch K, Sampognaro R, Navarra E, et al. Long-term results after repair of type A acute aortic dissection according to false lumen patency. Ann Thorac Surg 2009;88: Tsai TT, Evangelista A, Nienaber CA, et al. Partial thrombosis of the false lumen in patients with acute Type B aortic dissection. NEJM 2007;357: Akutsu K, Nejima J, Kiuchi K, et al. Effects of the patent false lumen on the long-term outcome of the type B acute aortic dissection. Eur J Cardiothorac Surg 2004;26: Conrad MF, Crawford RS, Kwolek CJ, Brewster DC, Brady TJ, Cambria RP. Aortic remodeling after endovascular repair of acute complicated type B aortic dissection. J Vasc Surg 2009; 50: by The Society of Thoracic Surgeons /09/$36.00 Published by Elsevier Inc doi: /j.athoracsur