Current Management of Chronic Type B Aortic Dissection
Between June 2005 and December 2013, 107 patients at our institution underwent index repair of CTBAD, of whom 75 (70%) underwent endovascular-based procedures (44 TEVAR, 27 hybrid arch, four hybrid TAAA) and 32 (30%) underwent open procedures (nine open descending, 23 open TAAA). The proportion of patients undergoing endovascular repair was equivalent between the first [2005–2009] and second [2010–2013] halves of the study period [42 of 56 (75%) vs. 33 of 51 (65%), P=0.29]. Demographic characteristics are shown in Table 1, and anatomic and procedural characteristics are shown in Table 2. CTD, prior aortic surgery and aortic dissection anatomy were strongly associated with the choice of operation. Ninety percent of CTD patients underwent open repair (the remaining CTD patient was a 77-year-old Marfan patient who underwent zone 0 hybrid arch repair with a Dacron proximal landing zone from prior ascending aortic replacement) compared to 24% of non-CTD patients. Approximately half of the patients in the study had a history of repaired DeBakey type I dissection with residual CTBAD, and only 17% of these patients were candidates for isolated TEVAR repair. Conversely, 60% of patients with isolated descending aortic dissection (DeBakey type IIIa or IIIb) underwent TEVAR as the index procedure. In concert with these findings, patients with a history of prior aortic surgery were less likely to undergo isolated TEVAR intervention and 80% required hybrid or open aortic reconstructions. In total, 80% of patients underwent elective operation and 20% underwent urgent or emergent repair for reasons outlined above.
Thirty-day in-hospital adverse events are listed in Table 3. The lowest rates of procedural morbidity and mortality were observed with isolated TEVAR, from which no patients experienced stroke, paraplegia or death within the perioperative period. The overall rates of stroke, paraplegia and operative mortality following any endovascular-based repair option were 0%, 0% and 4%, respectively, and the rate of retrograde type A aortic dissection was 4%. In contrast, adverse neurologic events were higher following open aortic repair, with cumulative rates of stroke, paraplegia and operative mortality of 16%, 9% and 6%, respectively. Hospital length of stay was also significantly longer following open repair (median 8 days versus median 4 days for endovascular repair, P=0.001).
To further examine factors associated with poor outcomes in the open repair group, univariate risk factors for major morbidity (stroke, paraplegia/paraparesis or dialysis) or death within 1-year follow-up of operation were assessed (Table 4). In total, 25% (8 of 32) of open repair patients experienced major morbidity or 1-year mortality. The strongest univariate risk factors for poor outcomes were older age and operation within the first half of the study period. Notably, CTD patients did well following open surgery and only 1 of 9 (11%) experienced a major adverse event in the form of a small subdural hematoma secondary to lumbar cerebrospinal fluid drainage that was managed conservatively.
Overall and aorta specific survival for the entire patient cohort is depicted in Figure 1. The overall 1-, 3-, and 5-year survival rates were 87% [95% confidence interval (CI), 80–93%], 77% (95% CI, 68–86%) and 69% (95% CI, 59–80%), respectively, and 5-year aorta specific survival was 92% (95% CI, 87–98%). The aortic deaths in the series (n=9) included six patients who died in the 30-day in-hospital period following the index operation (n=5) or staged reintervention for aortoesophageal fistula (n=1), two patients who died of late ascending aortic complications unrelated to the CTBAD repair, and one patient who experienced a type Ia endoleak following zone 0 hybrid arch repair where operative reintervention was deferred due to advanced dementia and other prohibitive comorbidities.
(Enlarge Image)
Figure 1.
Kaplan-Meier estimates of overall and aorta specific survival for all patients undergoing chronic type B aortic dissection repair.
Overall survival stratified by procedure type is shown in Figure 2. The 1-year survival rates were similar across procedures at 90% (95% CI, 82–100%) for TEVAR, 77% (95% CI, 63–95%) for hybrid arch, 100% (95% CI, 100–100%) for hybrid TAAA, 89% (95% CI, 71–100%) for open descending, and 87% (95% CI, 74–100%) for open TAAA repair. Cumulative 1- and 5-year survival rates were likewise similar between endovascular-based and open procedures and were 86% (78–95%) and 65% (53–80%), respectively, for endovascular-based repairs and 88% (77–100%) and 79% (65–96%), respectively, for open repairs.
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Figure 2.
Kaplan-Meier estimates of overall survival stratified by (A) endovascular or (B) open procedure type. TEVAR, thoracic endovascular aortic repair; TAAA, thoracoabdominal aortic aneurysm.
Reinterventions during follow-up are shown in Table 5, stratified by procedure type and location of aortic reintervention. In total, 17% of patients required reintervention for descending aortic pathology and 7% required reintervention for arch pathology, for a total aortic reintervention rate of 23%. Over a median follow-up interval of 34 months, the rate of descending aortic reintervention was 24% (n=18) following endovascular-based repairs and 0% following open repairs (P=0.001). Approximately half of the descending aortic reinterventions (8 of 18; 44%) were required to treat stent graft complications (five endoleak, two stent graft collapse, one stent graft-induced new entry tear) and the remainder were required to treat metachronous pathology (n=2) or progressive aneurysmal disease related to persistent distal fenestrations (n=8). The majority (11 of 18; 61%) of descending aortic reinterventions were able to be addressed via TEVAR alone. However, 9% (7 of 75) of endovascular-based repair patients ultimately required conversion to hybrid arch, hybrid TAAA or open TAAA repair due to type Ia endoleak (n=1), aortoesophageal fistula (n=1) or persistent distal fenestrations leading to continued proximal aneurysm expansion or distal aneurysm disease (n=5). Overall freedom from descending aortic reintervention rates for endovascular patients are shown in Figure 3. At 3-years, freedom from descending aortic reintervention rates were 68% (95% CI, 54–85%) for TEVAR, 82% (95% CI, 67–100%) for hybrid arch and 25% (95% CI, 5–100%) for hybrid TAAA repairs. Reintervention for arch pathology was required in seven patients, including two TEVAR patients who underwent emergent repair of retrograde type A aortic dissection (the remaining retrograde type A aortic dissection patient died prior to operative intervention). All other arch reinterventions entailed treatment of metachronous arch pathology unrelated to the CTBAD repair.
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Figure 3.
Kaplan-Meier estimates of freedom from descending aortic reintervention stratified by endovascular procedure type. TEVAR, thoracic endovascular aortic repair; TAAA, thoracoabdominal aortic aneurysm.
Results
Demographic, Anatomic, and Procedural Data
Between June 2005 and December 2013, 107 patients at our institution underwent index repair of CTBAD, of whom 75 (70%) underwent endovascular-based procedures (44 TEVAR, 27 hybrid arch, four hybrid TAAA) and 32 (30%) underwent open procedures (nine open descending, 23 open TAAA). The proportion of patients undergoing endovascular repair was equivalent between the first [2005–2009] and second [2010–2013] halves of the study period [42 of 56 (75%) vs. 33 of 51 (65%), P=0.29]. Demographic characteristics are shown in Table 1, and anatomic and procedural characteristics are shown in Table 2. CTD, prior aortic surgery and aortic dissection anatomy were strongly associated with the choice of operation. Ninety percent of CTD patients underwent open repair (the remaining CTD patient was a 77-year-old Marfan patient who underwent zone 0 hybrid arch repair with a Dacron proximal landing zone from prior ascending aortic replacement) compared to 24% of non-CTD patients. Approximately half of the patients in the study had a history of repaired DeBakey type I dissection with residual CTBAD, and only 17% of these patients were candidates for isolated TEVAR repair. Conversely, 60% of patients with isolated descending aortic dissection (DeBakey type IIIa or IIIb) underwent TEVAR as the index procedure. In concert with these findings, patients with a history of prior aortic surgery were less likely to undergo isolated TEVAR intervention and 80% required hybrid or open aortic reconstructions. In total, 80% of patients underwent elective operation and 20% underwent urgent or emergent repair for reasons outlined above.
Procedural Outcomes
Thirty-day in-hospital adverse events are listed in Table 3. The lowest rates of procedural morbidity and mortality were observed with isolated TEVAR, from which no patients experienced stroke, paraplegia or death within the perioperative period. The overall rates of stroke, paraplegia and operative mortality following any endovascular-based repair option were 0%, 0% and 4%, respectively, and the rate of retrograde type A aortic dissection was 4%. In contrast, adverse neurologic events were higher following open aortic repair, with cumulative rates of stroke, paraplegia and operative mortality of 16%, 9% and 6%, respectively. Hospital length of stay was also significantly longer following open repair (median 8 days versus median 4 days for endovascular repair, P=0.001).
To further examine factors associated with poor outcomes in the open repair group, univariate risk factors for major morbidity (stroke, paraplegia/paraparesis or dialysis) or death within 1-year follow-up of operation were assessed (Table 4). In total, 25% (8 of 32) of open repair patients experienced major morbidity or 1-year mortality. The strongest univariate risk factors for poor outcomes were older age and operation within the first half of the study period. Notably, CTD patients did well following open surgery and only 1 of 9 (11%) experienced a major adverse event in the form of a small subdural hematoma secondary to lumbar cerebrospinal fluid drainage that was managed conservatively.
Survival
Overall and aorta specific survival for the entire patient cohort is depicted in Figure 1. The overall 1-, 3-, and 5-year survival rates were 87% [95% confidence interval (CI), 80–93%], 77% (95% CI, 68–86%) and 69% (95% CI, 59–80%), respectively, and 5-year aorta specific survival was 92% (95% CI, 87–98%). The aortic deaths in the series (n=9) included six patients who died in the 30-day in-hospital period following the index operation (n=5) or staged reintervention for aortoesophageal fistula (n=1), two patients who died of late ascending aortic complications unrelated to the CTBAD repair, and one patient who experienced a type Ia endoleak following zone 0 hybrid arch repair where operative reintervention was deferred due to advanced dementia and other prohibitive comorbidities.
(Enlarge Image)
Figure 1.
Kaplan-Meier estimates of overall and aorta specific survival for all patients undergoing chronic type B aortic dissection repair.
Overall survival stratified by procedure type is shown in Figure 2. The 1-year survival rates were similar across procedures at 90% (95% CI, 82–100%) for TEVAR, 77% (95% CI, 63–95%) for hybrid arch, 100% (95% CI, 100–100%) for hybrid TAAA, 89% (95% CI, 71–100%) for open descending, and 87% (95% CI, 74–100%) for open TAAA repair. Cumulative 1- and 5-year survival rates were likewise similar between endovascular-based and open procedures and were 86% (78–95%) and 65% (53–80%), respectively, for endovascular-based repairs and 88% (77–100%) and 79% (65–96%), respectively, for open repairs.
(Enlarge Image)
Figure 2.
Kaplan-Meier estimates of overall survival stratified by (A) endovascular or (B) open procedure type. TEVAR, thoracic endovascular aortic repair; TAAA, thoracoabdominal aortic aneurysm.
Reinterventions During Follow-up
Reinterventions during follow-up are shown in Table 5, stratified by procedure type and location of aortic reintervention. In total, 17% of patients required reintervention for descending aortic pathology and 7% required reintervention for arch pathology, for a total aortic reintervention rate of 23%. Over a median follow-up interval of 34 months, the rate of descending aortic reintervention was 24% (n=18) following endovascular-based repairs and 0% following open repairs (P=0.001). Approximately half of the descending aortic reinterventions (8 of 18; 44%) were required to treat stent graft complications (five endoleak, two stent graft collapse, one stent graft-induced new entry tear) and the remainder were required to treat metachronous pathology (n=2) or progressive aneurysmal disease related to persistent distal fenestrations (n=8). The majority (11 of 18; 61%) of descending aortic reinterventions were able to be addressed via TEVAR alone. However, 9% (7 of 75) of endovascular-based repair patients ultimately required conversion to hybrid arch, hybrid TAAA or open TAAA repair due to type Ia endoleak (n=1), aortoesophageal fistula (n=1) or persistent distal fenestrations leading to continued proximal aneurysm expansion or distal aneurysm disease (n=5). Overall freedom from descending aortic reintervention rates for endovascular patients are shown in Figure 3. At 3-years, freedom from descending aortic reintervention rates were 68% (95% CI, 54–85%) for TEVAR, 82% (95% CI, 67–100%) for hybrid arch and 25% (95% CI, 5–100%) for hybrid TAAA repairs. Reintervention for arch pathology was required in seven patients, including two TEVAR patients who underwent emergent repair of retrograde type A aortic dissection (the remaining retrograde type A aortic dissection patient died prior to operative intervention). All other arch reinterventions entailed treatment of metachronous arch pathology unrelated to the CTBAD repair.
(Enlarge Image)
Figure 3.
Kaplan-Meier estimates of freedom from descending aortic reintervention stratified by endovascular procedure type. TEVAR, thoracic endovascular aortic repair; TAAA, thoracoabdominal aortic aneurysm.
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