Toward the best treatment for uncomplicated patients with type B acute aortic dissection: A consideration for sound surgical indication

Long-Term Outcomes of Chronic Type B Aortic Dissection Treated by Thoracic Endovascular Aortic Repair

Background The treatment of chronic type B aortic dissection by thoracic endovascular aortic repair has some challenges, and its long-term outcomes remain unclear. This study aimed to analyze the 5-year clinical outcomes of thoracic endovascular aortic repair of chronic type B aortic dissection, compare the differences between patients with and without adverse aortic events (AAEs), and identify risk factors for AAEs. Methods and Results Patients who underwent thoracic endovascular aortic repair of chronic type B aortic dissection from January 2009 to June 2017 were retrospectively enrolled. The primary end points were AAEs, including aorta-related death, procedural complications, and disease progression requiring reintervention. Clinical outcomes were described at the 5-year follow-up visit. The secondary end point was the comparison of the results between patients with and without AAEs. Univariable and multivariable logistic analyses were used to identify potential risk factors for AAEs. A total of 214 patients were enrolled. AAEs occurred in 46 (21.5%) patients. Compared with patients without AAEs, those with AAEs had higher rates of residual type A aortic dissection (26.1% versus 4.2%, P<0.001) and aortic diameter ≥5.5 cm (69.6% versus 11.3%, P<0.001), and a lower rate of complete false lumen thrombosis (23.9% versus 89.9%, P<0.001). Meanwhile, the median interval from symptom onset to intervention was longer in patients with AAEs (26 months versus 12 months, P=0.004). Partial or no false lumen thrombosis (adjusted odds ratio [AOR], 14.71 [95% CI, 5.67-38.14; P<0.001]) and aortic diameter ≥5.5 cm (AOR, 10.16 [95% CI, 3.86-26.73; P<0.001]) were identified as independent risk factors for AAEs. Conclusions While thoracic endovascular aortic repair of chronic type B aortic dissection might be challenging in some cases, its long-term outcomes appeared promising as this treatment was effective in preventing catastrophic aortic events. Patients with AAEs showed higher rates of residual type A aortic dissection and aortic diameter ≥5.5 cm, a lower rate of complete false lumen thrombosis, and a longer median interval from symptom onset to intervention. Failure of complete false lumen thrombosis and an aortic diameter ≥5.5 cm were predictors of AAEs.

Predictors of adverse events in uncomplicated type B aortic dissection: a systematic review with meta-analysis

INTRODUCTION

Thoracic Endovascular Aortic Repair (TEVAR) has been selectively used for uncomplicated acute type B Aortic Dissection (TBAD); however, not all cases will benefit from TEVAR. A search for high risk clinical and radiographic predictors for complications is ongoing. This systematic review and meta-analysis aimed to identify predictors of major adverse events during follow-up of uncomplicated TBAD, in order to identify who might benefit from elective TEVAR.

EVIDENCE ACQUISITION

A systematic review was conducted according to the Preferred Reporting Items for Systematic reviews and Meta-analysis (PRISMA) statement.

EVIDENCE SYNTHESIS

16 studies were included in a qualitative synthesis and 10 in the meta-analysis. Several risk factors associated to major adverse events have been described, including (1) aortic diameter ≥40 mm, (2) greater false lumen diameter (>22mm), (3) patent false lumen, (4) primary entry tear > 10mm, and (5) greater number of false lumen vessels origin. Quantitative synthesis identified an aortic diameter ≥40 mm significantly associated with major adverse events (HR=3.56; p<0.00001). Reporting of false lumen status, aortic diameters and growth, and demographic data was not always congruent with the most recent recommendations by Society for Vascular Surgery and Society of Thoracic Surgeons, published in 2020.

CONCLUSIONS

Acute and subacute patients with uncomplicated TBAD presenting with an aortic diameter ≥ 40 mm and solely treated with BMT have an increased hazard of developing major adverse events (HR), making them potential candidates for TEVAR. Remaining risk factors analysed have weaker evidence.

Association of hemodynamic factors and progressive aortic dilatation following type A aortic dissection surgical repair

Type A aortic dissection (TAAD) involves the ascending aorta or the arch. Acute TAAD usually requires urgent replacement of the ascending aorta. However, a subset of these patients develops aortic rupture due to further dilatation of the residual dissected aorta. There is currently no reliable means to predict the risk of dilatation following TAAD repair. In this study, we performed a comprehensive morphological and hemodynamic analysis for patients with and without progressive aortic dilatation following surgical replacement of the ascending aorta. Patient-specific models of repaired TAAD were reconstructed from post-surgery computed tomography images for detailed computational fluid dynamic analysis. Geometric and hemodynamic parameters were evaluated and compared between patients with stable aortic diameters (N = 9) and those with aortic dilatation (N = 8). Our results showed that the number of re-entry tears and true/false lumen pressure difference were significantly different between the two groups. Patients with progressive aortic dilatation had higher luminal pressure difference (6.7 [4.6, 10.9] vs. 0.9 [0.5, 2.3] mmHg; P = 0.001) and fewer re-entry tears (1.5 [1, 2.8] vs. 5 [3.3, 7.5]; P = 0.02) compared to patients with stable aortic diameters, suggesting that these factors may serve as potential predictors of aneurysmal dilatation following surgical repair of TAAD.

Timing of thoracic endovascular aortic repair for uncomplicated acute type B aortic dissection and the association with complications

OBJECTIVE

Previous publications have clearly established a correlation between timing of thoracic endovascular aortic repair (TEVAR) and complications after treatment of complicated acute type B aortic dissection (ATBAD). However, the temporal association of TEVAR with morbidity after uncomplicated presentations is poorly understood and has not previously been examined using real-world national data. Therefore, the objective of this analysis was to determine whether TEVAR timing of uncomplicated ATBAD (UATBAD) is associated with postoperative complications.

METHODS

The Vascular Quality Initiative TEVAR and complex endovascular aneurysm repair registry was analyzed from 2010 to 2019. Procedures performed for non-dissection-related disease as well as for ATBAD with malperfusion or rupture were excluded. Because of inherent differences between timing cohorts, propensity score matching was performed to ensure like comparisons. Univariate and multivariable analysis after matching was used to determine differences between timing groups (symptom onset to TEVAR: acute, 1-14 days; subacute, 15-90 days) for postoperative mortality, in-hospital complications, and reintervention.

RESULTS

A total of 688 cases meeting inclusion criteria were identified. After matching 187 patients in each of the 1- to 14-day and 15- to 90-day treatment groups, there were no statistically significant differences between groups. On univariate analysis, the 1- to 14-day treatment group had a higher proportion of cases requiring reintervention within 30 days (15.3%) compared with UATBAD patients undergoing TEVAR within 15 to 90 days (5.2%; P = .02). There was also a difference (P = .007) at 1 year, with 33.8% of the 1- to 14-day UATBAD patients undergoing reintervention compared with 14.5% for the 15- to 90-day group. There were no statistically significant differences on multivariable analysis for long-term survival, complications, or long-term reintervention. There was a trend toward significance (P = .08) with the 1- to 14-day group having 2.3 times the odds of requiring an in-hospital reintervention compared with the 15- to 90-day group.

CONCLUSIONS

Timing of TEVAR for UATBAD does not appear to predict mortality or postoperative complications. However, there is a strong association between repair within 1 to 14 days and higher risk of reintervention. This may in part be related to the 1- to 14-day group's representing an inherently higher anatomic or physiologic risk population that cannot be entirely accounted for with propensity analysis. The role of optimal timing to intervention should be incorporated into future study design of TEVAR trials for UATBAD.

Outcomes of fenestrated and branched endovascular aortic repair for chronic post-dissection thoracoabdominal aortic aneurysms

BACKGROUND

Aneurysmal degeneration after acute dissection occurs in a significant proportion of patients. Fenestrated and branched stent-grafting (F/BEVAR) has been increasingly used to treat these post-dissection thoracoabdominal aortic aneurysms (PD-TAAA). The aim of this study was to report early and mid-term outcomes of F/BEVAR in PD-TAAA.

METHODS

Retrospective single center analysis of a prospectively maintained database including all patients undergoing F/BEVAR for PD-TAAA between October 2010-February 2020.

RESULTS

Fifty-five patients (45 males, mean age 66±10 years) were included. Technical success was achieved in all patients. Thirty-day mortality was two (3.6%) patients. Major perioperative complications were noted in nine (16.4%) patients including five (9.1%) with transient spinal cord ischemia (SCI) and one (1.8%) with permanent paraplegia. Mean follow-up was 24 months (1-76 months). Cumulative survival rates at 12, 24 and 36 months were 87±5.5%, 83.5±6.3% and 72.2±8.1%, respectively. Estimated freedom from reintervention at 12, 24 and 36 months was 82.2±6.7%, 60.1±9.2% and 55.9±9.5%, respectively. Main reasons for reintervention were endoleaks from target vessels and common iliac arteries. Estimated target vessel patency at 12, 24 and 36 months was 97.8±1.2%, 95.4±2.1%, and 94.1±2.4%, respectively. Mean aneurysm sac regression during follow-up was 7.9±7.1 mm, with complete false lumen thrombosis in 80% of patients. No ruptures occurred during follow-up.

CONCLUSIONS

F/BEVAR for PD-TAAA is associated with low perioperative mortality and morbidity in a large volume endovascular center. Mid-term results demonstrate a high rate of aneurysm sac regression. Extended sealing with longer bridging stents for target vessels is recommended.

The Safety and Efficacy of Extended TEVAR in Acute Type B Aortic Dissection

BACKGROUND

Thoracic endovascular aortic repair (TEVAR) with endograft coverage from the left subclavian artery to the celiac artery has been hypothesized to increase spinal cord ischemia. This study analyzes the impact of extended coverage on adverse outcomes and aortic remodeling in patients with complicated acute type B aortic dissection (aTBAD).

METHODS

From January 2012 to October 2018, 91 patients underwent TEVAR for aTBAD. Median follow-up was 3.1 (interquartile range, 1.2-4.9) years and was complete in 94% of patients. The extent of aortic endograft coverage was categorized as standard (n = 39) or extended (n = 52). Contrast-enhanced imaging scans were analyzed to determine length of coverage, maximum aortic diameters, and false lumen (FL) status.

RESULTS

The mean age was 52.6 ± 13.9 years, and 66% were men. The most common indications for intervention were malperfusion (42%) and refractory pain (34%). Thirteen (14%) patients required a lumbar drain (preoperative: n = 3; postoperative: n = 10). Mean duration between scans was 2.0 ± 1.9 years. Length of aortic coverage was significantly longer in the extended group (241.7 ± 29.2 mm vs 180.8 ± 22.3 mm in the standard group; P < .001). In-hospital and overall mortality were 6% and 11%, respectively. There were no cases of paraplegia, and the incidence of spinal cord ischemia was 3%. After TEVAR, there was a higher incidence of FL obliteration or thrombosis at the distal descending thoracic aorta in the extended group (53% vs 16% in the standard group; P = .004).

CONCLUSIONS

Extended TEVAR carries a low risk of spinal cord ischemia and improves FL remodeling of the descending thoracic aorta in patients with aTBAD. This strategy may decrease the need for reinterventions on the thoracic aorta in the chronic phase of TBAD.

Acute Type B Dissection

Aortic dissections are catastrophic vascular emergencies, and early recognition and appropriate interventions can be crucial to survival. Research has changed the way aortic dissections are managed over the past two decades and will continue to contribute to the evolution of treatment modalities. Early treatment for uncomplicated type B dissections still remains controversial but certain characteristics may benefit from early intervention.

Thoracic Endovascular Aortic Repair for Acute Aortic Dissection

Thoracic endovascular aortic repair (TEVAR) for thoracic aortic disease constitutes a paradigm shift in the treatment strategy of aortic dissection, as well as thoracic aortic aneurysms. Conventionally, most patients with Stanford type B acute aortic dissection are treated using conservative medical treatment during the acute phase. However, in patients with complicated type B aortic dissection who present with life-threatening complications, TEVAR has been introduced as a novel and less-invasive alternative and has shown better early results than those observed with conventional therapy. Recently, TEVAR was reported to be effective in not only promoting thrombosis of the false lumen but also in preventing aortic enlargement observed at long-term follow-up. TEVAR has been established as first-line therapy for complicated type B aortic dissection. In contrast, a considerable number of patients who received acute phase medical treatment required surgical intervention for chronic dissecting aortic aneurysms. With the increasing popularity of TEVAR for the treatment of complicated type B aortic dissection, prophylactic and pre-emptive TEVAR has been considered in patients with uncomplicated type B aortic dissection. However, supportive evidence for this strategy is limited, and reassessment is mandatory because it is continuously evolving. Although acute type A aortic dissection is a life-threatening condition, the results of open surgery continue to improve in the modern surgical era. Open surgical treatment is well established and recognized as a gold standard even in the endovascular era. Presently, the application of TEVAR for ascending aortic dissection has undergone a change, and TEVAR is considered a viable rescue option for patients with type A aortic dissection who are not eligible for open surgical repair. However, TEVAR for the descending aorta is well-established treatment for retrograde type A dissection. Several conceptual and technical issues remain unresolved, and technological advances would lead to the development of innovative disease-specific devices and solutions in the future for endovascular treatment of acute aortic dissection. (This is a translation of Jpn J Vasc Surg 2018; 27: 337–345.)

Analysis of Risk Factors for Aortic Enlargement in Patients with Chronic Type B Aortic Dissection

Objectives: Uncomplicated type B aortic dissection is generally treated with medical management including antihypertensive therapy. The purpose of this study is to investigate risk factors associated with the aortic enlargement in medically treated patients. Methods: Between July 2004 and April 2016, 127 consecutive patients with acute type B aortic dissection were treated in our institution. Of these, 104 patients diagnosed with uncomplicated type B dissection were managed medically as an initial treatment. According to the diameter of the dissected aorta, these patients were retrospectively placed into 2 groups: 1) enlargement group (group E: n=36); and 2) unchanged group (group U: n=68). Results: There was statistically significant difference regarding the initial diameter of the dissected aorta (group E: 42±7 mm, group U: 36±7 mm) (p<0.01). As regards the aneurysm growth rate, a significant difference between both groups was noted (group E: 10±32 mm/half-year, group U -3±19 mm/half-year) (p<0.05). In all 104 patients, 42 patients (40.4%) had patent false lumen with the average number of 1.5 intimal tears. Multivariate analysis showed the relationship for aortic enlargement were patent false lumen (p<0.05, 95%CI 0.407-0.935) and initial aortic diameter (p<0.01, 95%CI 1.076-1.158). Aortic event free survival (1/5/10 years) was 100/86/77% in group E and 92/79/79% in group U, respectively no differences between two groups (p=0.747). Conclusions: The medically managed patients with uncomplicated chronic type B dissection showed excellent survival rate during long-term follow-up. The results of surgical or endovascular treatment in patients underwent initial medical therapy were also satisfactory. The patent false lumen and aortic diameter at the onset may impact on aortic enlargement. Considering our results, the feasibility of elective endovascular repairs in stable dissection remains controversial even in the endovascular era. (This is a translation of Jpn J Vasc Surg 2018; 27: 55-60.).

The distance of the primary intimal tear from the left subclavian artery predicts aortic growth in uncomplicated type B aortic dissection

OBJECTIVE

Controversy exists about the optimal treatment of acute uncomplicated type B aortic dissection (auTBAD). Optimal medical therapy (OMT) provides excellent short-term outcomes, but long-term results are poor. Ideally, auTBAD patients who will fail to respond to OMT in the chronic phase could be identified and undergo thoracic endovascular aortic repair. The purpose of this study was to identify radiographic predictors of auTBAD patients who will fail to respond to OMT.

METHODS

A review of the Emory aortic database from 2000 to 2017 identified 320 auTBAD patients initially treated with OMT. From this cohort, 121 patients with two or more contrast-enhanced imaging scans were available for analysis. These patients were initially divided into groups based on growth of the thoracic aorta ≥10 mm or intervention due to aneurysmal growth: growth (n = 72) and no growth (n = 49). TeraRecon (Foster City, Calif) imaging software was used to analyze characteristics of the primary intimal tear (PIT), false lumen, and overall aortic size. Finally, Cox proportional hazards models were constructed to estimate hazard ratios and to identify predictors of OMT failure.

RESULTS

The mean age of all patients was 54 ± 11 years, and 67% were male. Thirty-eight patients (53%) in the growth group underwent intervention. There were no differences between groups in age, hypertension, diabetes mellitus, tobacco abuse, or chronic obstructive pulmonary disease. The distance of the PIT from the left subclavian artery in patients with auTBAD was significantly shorter in the growth group (growth, 27 mm [9-66 mm]; no growth, 77 mm [26-142 mm]; P < .01). Multivariable Cox regression analysis identified the distance of the PIT from the left subclavian artery and a thoracic aortic diameter >45 mm as independent predictors of failure of OMT. Partial false lumen thrombosis was not a predictor of aortic growth.

CONCLUSIONS

The distance of the PIT from the left subclavian artery is a predictor of aortic growth in auTBAD. Patients with a primary tear located in zone 3 of the proximal descending thoracic aorta should be monitored closely and may be considered for early thoracic endovascular aortic repair in the setting of auTBAD.

Fate of uncomplicated acute type B aortic dissection and impact of concurrent aortic dilatation on remote aortic events

OBJECTIVE

This study aimed to describe the reliable prognostic factors of mortality and subsequent aortic events during the follow-up of uncomplicated type B acute aortic dissection.

METHODS

From January 2004 to December 2014, 255 patients with uncomplicated type B acute aortic dissection were admitted to our hospital. Cox proportional hazards analysis was performed to identify risk factors for all-cause mortality, aorta-related mortality, and aortic events.

RESULTS

In-hospital mortality was observed in 7 patients (2.7%). The rates of 5-year freedom from all-cause mortality, aorta-related mortality, and aortic events were 79.4% ± 2.9%, 93.3% ± 2.0%, and 71.7% ± 3.4%, respectively. The rate of 5-year freedom from aortic events was significantly lower among those with a patent false lumen (P = .006). Age and descending aorta diameter were independent risk factors of all-cause and aorta-related mortality (hazard ratio [HR], 1.08 and 1.13; 95% confidence interval [CI], 1.04-1.10 and 1.03-1.24; P = .0001 and .007, respectively). Independent risk factors for aortic events were descending aorta diameter, false lumen thickness, and dilatation of abdominal aorta (HR, 1.06; 95% CI, 1.02-1.12; P = .006; HR, 1.07; 95% CI, 1.04-1.11; P = .00002; HR, 2.01; CI, 1.20-3.38; P = .008).

CONCLUSIONS

In uncomplicated type B acute aortic dissection, the age and dilatation of the thoracic aorta were associated with a higher risk of death, whereas false lumen thickness and concurrent abdominal aortic dilatation augment the risk for aortic events.

Techniques and outcomes of secondary endovascular repair for postdissection TAA/TAAA

Postdissection aortic aneurysms (PDAA) affect 20-40% of patients with aortic dissection. Open repair remains the first line therapy of PDAA, but is still associated with high mortality and morbidity rates. Endovascular repair is increasingly being used as a less invasive treatment option. Thoracic endovascular aneurysm repair (TEVAR) covering only the proximal entry tear has proven to be insufficient in most patients with chronic PDAA and has a limited role only for PDAA with distal sealing zone in the thoracic aorta. In PDAA extending to the thoracoabdominal aorta, a more complex repair is needed to achieve aneurysm exclusion. Fenestrated and branched stent-grafts have been used lately in some expert centres to treat PDAA of the thoracoabdominal aorta with good preliminary results despite the technical difficulties in these patients (narrow true lumen, stiff chronic dissection flap, target vessels that originate from the false lumen [FL]). A subset of patients with aneurysmal degeneration mainly in the descending thoracic aorta, can be treated with TEVAR landing proximal to the celiac artery along with adjuvant techniques such as coils, plugs, glue or "Candy-Plug" and "Knickerbocker" concepts to occlude the FL, preventing retrograde flow and reducing the pressure in the aneurysm. Other options that have been used in limited numbers of patients with PDAA include the PETTICOAT (provisional extension to induce complete attachment) and STABILISE (Stent-Assisted Balloon-Induced Intimal Disruption and Relamination in Aortic Dissection Repair) techniques. This article aims to review the outcomes of different endovascular techniques and strategies available for the repair of PDAA.

Endovascular Treatment of Various Aortic Pathologies: Review of the Latest Data and Technologies

The technologies and innovations applicable to endovascular treatment for complex aortic pathologies have progressed rapidly over the last two decades. Although the initial outcomes of an endovascular aortic repair have been excellent, as long-term data became available, complications including endoleaks, endograft migration, and endograft infection have become apparent and are of concern. Previously, the indication for endovascular therapy was restricted to descending thoracic aortic aneurysms and abdominal aortic aneurysms. However, its indication has expanded along with the improvement of techniques and devices, and currently, it has become possible to treat pararenal aortic aneurysms and Crawford type 4 thoracoabdominal aortic aneurysm (TAAA) using the off-the-shelf devices. Additionally, custom-made devices allow for the treatment of arch or more extensive TAAAs. Endovascular treatment is applied not only to aneurysms but also to acute/chronic dissections. However, long-term outcomes are still unclear. This article provides an overview of available devices and the results of endovascular treatment for various aortic pathologies.

Outcomes of Thoracic Endovascular Aortic Repair for Acute Type B Dissection in Patients With Intractable Pain or Refractory Hypertension

PURPOSE

To compare uncomplicated acute type B aortic dissection (UATBAD) patients with intractable pain/refractory hypertension treated with thoracic endovascular aortic repair (TEVAR) to UATBAD subjects without these features receiving best medical therapy (BMT).

METHODS

Interrogation of the hospital database identified 101 consecutive UATBAD patients admitted between January 2011 and December 2014. Of these, 74 patients (mean age 62±13 years; 44 men) were treated with BMT; the other 27 UATBAD patients (mean age 63±13 years; 17 men) were subsequently treated with TEVAR for intractable pain (24, 89%) and/or refractory hypertension (3, 11%) at a mean 2.4±3.3 days (median 1, range 0-12) after admission. Mixed models were employed to determine differences in centerline measured aortic remodeling. Propensity analysis was employed to mitigate selection bias. Kaplan-Meier methodology was used to estimate reintervention and survival.

RESULTS

The groups were well matched; there was no difference in demographics, comorbidities, or proportion with visceral involvement (70% for TEVAR vs 86% for BMT, p=0.08). There was no significant difference in length of stay (9.6±6.3 for TEVAR vs 10.3±7.8 for BMT, p=0.3), complications (19% for TEVAR vs 24% for BMT, p=0.6), or 30-day mortality (0 for TEVAR vs 7% for BMT, p=0.1). One (4%) TEVAR patient experienced retrograde dissection. BMT resulted in greater mean increase in discharge antihypertensive medications (1.7±1.9 vs 0.7±1.7 for TEVAR, p=0.03), but there was no difference in narcotic utilization. Mean follow-up was greater in the TEVAR group (17.9±16.0 months) compared with BMT patients (11.5±10.8 months, p=0.05). TEVAR significantly improved rates of aortic diameter change (1.5% vs 12.9% for BMT, p=0.007), complete false lumen thrombosis (41% vs 11% for BMT, p=0.004), and true lumen expansion (85% vs 7% for BMT, p<0.01). However, there was no difference in reintervention (25.9% for TEVAR vs 23% for BMT, p=0.2) or survival (log-rank p=0.8).

CONCLUSION

TEVAR for UATBAD with intractable pain/refractory hypertension is safe but offers no short-term outcome advantage when compared to UATBAD patients without these features receiving BMT. A significant improvement in aortic remodeling was identified after TEVAR. The potential long-term reintervention and aorta-related mortality benefits of this favorable remodeling have yet to be defined and randomized trials are warranted.

Update on the Therapeutic Strategy of Type B Aortic Dissection

Stanford type B aortic dissection (TBAD) is a life-threatening disease. Current therapeutic guidelines recommend medical therapy with aggressive blood pressure lowering for patients with acute TBAD unless they have fatal complications. Although patients with uncomplicated TBAD have relatively low early mortality, aorta-related adverse events during the chronic phase worsen the long-term clinical outcome. Recent advances in thoracic endovascular aortic repair (TEVAR) can improve clinical outcomes in patients with both complicated and uncomplicated TBAD. According to present guidelines, complicated TBAD patients are recommended for TEVAR. However, the indication in uncomplicated TBAD remains controversial. Recent results of randomized trials, which compared the clinical outcome in patients treated with optimal medical therapy and those treated with TEVAR, suggest that preemptive TEVAR should be considered in uncomplicated TBAD with suitable aortic anatomy. However, these trials failed to show improvement in early mortality in patients treated with TEVAR compared with patients treated with optimal medical therapy, which suggest the importance of patient selection for TEVAR. Several clinical and imaging-related risk factors have been shown to be associated with early disease progression. Preemptive TEVAR might be beneficial and should be considered for high-risk patients with uncomplicated TBAD. However, an interdisciplinary consensus has not been established for the definition of patients at high-risk of TBAD, and it should be confirmed by experts including physicians, radiologists, interventionalists, and vascular surgeons. This review summarizes the current understanding of the therapeutic strategy in patients with TBAD based on evidence and expert consensus.

Serial CT Volume and Thrombus Length Measurements after Endovascular Repair of Stanford Type B Aortic Dissection

Purpose:

To evaluate the outcome of stent-graft placement in Stanford type B aortic dissection using contrast-enhanced spiral computed tomographic (CT) measurements of true and false lumen volumes and thrombus length.

Methods:

Among 18 consecutive patients (13 men; mean age 60 years, range 44–79) who underwent endovascular repair of Stanford type B dissection, 12 completed at least a 12-month follow-up, which included CT measurements of true and false lumen volumes and thrombus lengths prior to discharge and at 6 and 12 months postimplantation. Volumes were assessed in 3 different aortic segments (A1, A2, A3) extending from the proximal attachment site of the prosthesis to the aortic bifurcation. In addition, thrombus length was measured to evaluate the influence of clot formation on outcome of the false lumen volume.

Results:

Mean follow-up was 27 months (range 12–60). Within 12 months, mean true lumen volumes showed statistically significant increases in the A1 (p<0.001) and A2 (p=0.003) segments; false lumen volumes showed a significant decrease in the A1 segment (p=0.002) but an insignificant increase in the A2 segment. No substantial volume changes were observed in the A3 segment. Extension of clot formation in the false lumen varied among patients and over time. Length of stent-grafts, percentage of stented dissection length, or visceral arteries originating from the false lumen did not significantly influence thrombus development, nor did these parameters or thrombus formation distal to the prosthesis have a relationship to false lumen volumes.

Conclusions:

Volumetric analysis after endovascular repair of Stanford type B dissection shows optimal technical outcome in the stented segment, whereas the false lumen in the segment immediately adjacent to the stent-graft seems to be a vulnerable area. Extension of clot formation beyond the endograft seems to be no reliable predictor of outcome.

A Retrospective Observational Study to Assess Prescription Pattern in Patients with Type B Aortic Dissection and Treatment Outcome

Aortic dissection is a life-threatening condition. However, the use of medication to treat it remains unclear in our population, particularly in patients with a type B aortic dissection (TBAD) who do not receive surgery. This retrospective cohort study evaluated antihypertensive prescription patterns and outcomes in patients with nonsurgical TBAD. We reviewed the hospital records of patients with TBAD at a medical center in Taiwan from January 2008 to June 2013 to assess the baseline information, prescribing pattern, event rate, and clinical effectiveness of different antihypertensive treatment strategies. A Cox proportional hazards model was used to estimate outcomes in different antihypertensive strategies. The primary endpoints were all-cause mortality and hospital admission for an aortic dissection. We included 106 patients with a mean follow-up period of 2.75 years. The most common comorbidity was hypertension followed by dyslipidemia and diabetes mellitus. Study endpoints mostly occurred within 6 months after the index date. Over 80% of patients received dual or triple antihypertensive strategies. Patients treated with different treatment strategies did not have a significantly increased risk of a primary outcome compared with those treated with a monotherapy. We found no significant difference in the primary outcome following the use of different antihypertensive medication regimes.

The new indication of TEVAR for uncomplicated type B aortic dissection

The classical therapeutic indication for type B aortic dissection is based on either medication or open surgery; medication therapy is recommended for relatively stable uncomplicated type B aortic dissection. With improvements in endovascular repair and the potential risk of disease progression, it is now necessary to evaluate the requirement for revision of the therapeutic choice of uncomplicated type B aortic dissection based on morphological features and time window. Data from 252 patients diagnosed as uncomplicated type B aortic dissection from 1992 to 2015 were analyzed retrospectively. Among these cases, 117 patients received medication therapy and 135 patients underwent endovascular repair. The 60-month survival rate in the endovascular group was higher than that in the medication group (92.3% vs 67.6%). According to the morphological evaluation, visceral artery involvement and false/true lumen ratios over 0.7 were strong risk factors for medical treatment alone. Increased surgical time and blood loss were found in patients treated in the chronic phase, compared with those who underwent endovascular repair within 14 days of the onset of symptoms. With improvements in aortic remodeling techniques, endovascular repair has been shown to improve long-term survival rates of patients with uncomplicated aortic dissection. Considering the potential risk of death, we recommend that patients with visceral artery involvement and a false/true lumen ratio over 0.7 should receive endovascular repair aggressively. Furthermore, delayed endovascular repair in the chronic phase does not improve the long-term outcome of uncomplicated type B aortic dissection.

Contemporary Management Strategies for Chronic Type B Aortic Dissections: A Systematic Review

Background

Currently, the optimal management strategy for chronic type B aortic dissections (CBAD) is unknown. Therefore, we systematically reviewed the literature to compare results of open surgical repair (OSR), standard thoracic endovascular aortic repair (TEVAR) or branched and fenestrated TEVAR (BEVAR/FEVAR) for CBAD.

Methods

EMBASE and MEDLINE databases were searched for eligible studies between January 2000 and October 2015. Studies describing outcomes of OSR, TEVAR, B/FEVAR, or all, for CBAD patients initially treated with medical therapy, were included. Primary endpoints were early mortality, and one-year and five-year survival. Secondary endpoints included occurrence of complications. Furthermore, a Time until Treatment Equipoise (TUTE) graph was constructed.

Results

Thirty-five articles were selected for systematic review. A total of 1081 OSR patients, 1397 TEVAR patients and 61 B/FEVAR patients were identified. Early mortality ranged from 5.6% to 21.0% for OSR, 0.0% to 13.7% for TEVAR, and 0.0% to 9.7% for B/FEVAR. For OSR, one-year and five-year survival ranged 72.0%-92.0% and 53.0%-86.7%, respectively. For TEVAR, one-year survival was 82.9%-100.0% and five-year survival 70.0%-88.9%. For B/FEVAR only one-year survival was available, ranging between 76.4% and 100.0%. Most common postoperative complications included stroke (OSR 0.0%-13.3%, TEVAR 0.0%-11.8%), spinal cord ischemia (OSR 0.0%-16.4%, TEVAR 0.0%-12.5%, B/FEVAR 0.0%-12.9%) and acute renal failure (OSR 0.0%-33.3%, TEVAR 0.0%-34.4%, B/FEVAR 0.0%-3.2%). Most common long-term complications after OSR included aneurysm formation (5.8%-20.0%) and new type A dissection (1.7–2.2%). Early complications after TEVAR included retrograde dissection (0.0%-7.1%), malperfusion (1.3%–9.4%), cardiac complications (0.0%–5.9%) and rupture (0.5%–5.0%). Most common long-term complications after TEVAR were rupture (0.5%–7.1%), endoleaks (0.0%–15.8%) and cardiac complications (5.9%-7.1%). No short-term aortic rupture or malperfusion was observed after B/FEVAR. Long-term complications included malperfusion (6.5%) and endoleaks (0.0%-66.7%). Reintervention rates after OSR, TEVAR and B/FEVAR were 5.8%-29.0%, 4.3%-47.4% and 0.0%-53.3%, respectively. TUTE for OSR was 2.7 years, for TEVAR 9.9 months and for B/FEVAR 10.3 months.

Conclusion

We found a limited early survival benefit of standard TEVAR over OSR for CBAD. Complication rates after TEVAR are higher, but complications after OSR are usually more serious. Initial experiences with B/FEVAR show its feasibility, but long-term results are needed to compare it to OSR and standard TEVAR. We conclude that optimal treatment of CBAD remains debatable and merits a patient specific decision. TUTE seems a feasible and useful tool to better understand management outcomes of CBAD.

Efficacy and Optimal Timing of Endovascular Treatment for Type B Aortic Dissection

OBJECTIVES

To determine the efficacy and the optimal timing of thoracic endovascular aortic repair (TEVAR) for closing the primary entry in uncomplicated patients with chronic type B aortic dissection and a patent false lumen (FL).

METHODS

Thirteen patients underwent TEVAR for aortic dissection between 2008 and 2012. These patients had chronic dissection with a patent FL and expansion of the aorta. Early TEVAR was performed for five patients within 1-7 months from the index dissection (TEVAR-EC group) and delayed TEVAR was performed for eight patients within 1-16 years (TEVAR-DC group). Changes in the diameters and volumes of the true lumen (TL) and FL and the aortic remodeling were assessed by multidetector computed tomography for 3 years after TEVAR.

RESULTS

The reduction rate of FL in the thoracic aorta was notably higher in the TEVAR-EC group than in the TEVAR-DC group regardless of the presence or absence of distal retrograde flow. There was a significant TL expansion despite different timings of TEVAR.

CONCLUSIONS

Early TEVAR resulted in good prognosis and preferable aortic remodeling in uncomplicated patients with chronic type B aortic dissection and a patent FL, and we recommend early TEVAR within seven months after the index dissection.

Relationship between acute kidney injury before thoracic endovascular aneurysm repair and in-hospital outcomes in patients with type B acute aortic dissection

Objective

Acute kidney injury (AKI) frequently occurs after catheter-based interventional procedures and increases mortality. However, the implications of AKI before thoracic endovascular aneurysm repair (TEVAR) of type B acute aortic dissection (AAD) remain unclear. This study evaluated the incidence, predictors, and in-hospital outcomes of AKI before TEVAR in patients with type B AAD.

Methods

Between 2009 and 2013, 76 patients were retrospectively evaluated who received TEVAR for type B AAD within 36 h from symptom onset. The patients were classified into no-AKI vs. AKI groups, and the severity of AKI was further staged according to kidney disease: improving global outcomes criteria before TEVAR.

Results

The incidence of preoperative AKI was 36.8%. In-hospital complications was significantly higher in patients with preoperative AKI compared with no-AKI (50.0% vs. 4.2%, respectively; P < 0.001), including acute renal failure (21.4% vs. 0, respectively; P < 0.001), and they increased with severity of AKI (P < 0.001). The maximum levels of body temperature and white blood cell count were significantly related to maximum serum creatinine level before TEVAR. Multivariate analysis showed that systolic blood pressure on admission (OR: 1.023; 95% CI: 1.003–1.044; P = 0.0238) and bilateral renal artery involvement (OR: 19.076; 95% CI: 1.914–190.164; P = 0.0120) were strong predictors of preoperative AKI.

Conclusions

Preoperative AKI frequently occurred in patients with type B AAD, and correlated with higher in-hospital complications and enhanced inflammatory reaction. Systolic blood pressure on admission and bilateral renal artery involvement were major risk factors for AKI before TEVAR.

Type B Aortic Dissection: A Review of Prognostic Factors and Meta-analysis of Treatment Options

According to international guidelines, stable patients with uncomplicated Type B aortic dissection (TBAD) should receive optimal medical treatment. Despite adequate antihypertensive therapy, the long-term prognosis of these patients is characterized by a significant aortic aneurysm formation in 25-30% within four years, and survival rates from 50 to 80% at five years and 30 to 60% at 10 years. In a prospective randomized trial, preemptive thoracic endovascular aortic repair (TEVAR) in patients with chronic uncomplicated TBAD was associated with an excess early mortality (due to periprocedural hazards), but the procedure showed its benefit in prevention of aortic-specific mortality at five years of follow-up. However, preemptive TEVAR may not be the treatment of choice in all patients with uncomplicated TBAD because of the inherent periprocedural complications like stroke, paraparesis, and death, as well as stent graft-induced complications (i.e., retrograde dissection or endoleaks). Thus, the TEVAR-related deaths and complications (especially paraplegia and stroke) raise concerns that moderate the better survival with TEVAR at five years. By timely identification of those patients prone for developing complications, early intervention, preferably in the subacute or early chronic phase, may improve the overall long-term outcome for these patients. Therefore, early detectable and reliable prognostic factors for adverse events are essential to stratify patients who can be treated medically and those who will benefit from rigorous follow-up and, in the long-term, from timely, or even prophylactic, TEVAR. Several studies have identified prognostic factors in TBAD such as aortic diameter, partial false lumen thrombosis, false lumen thickness, and location of the primary entry tear. Combining these clinical and radiological predictors may be essential to implement a patient-specific approach designed to intervene only in those patients who are at high risk of developing complications to improve the long-term outcomes of patients with uncomplicated Type B aortic dissection.

Usefulness of new imaging methods for assessment of type B aortic dissection

While the medical management of uncomplicated type B aortic dissection has good outcomes in the short term, the longer term mortality can be in the region of 50% at 5 years. Up to 40% of the survivors can have significant dilatation of the false lumen with the risk of aneurysm formation and death due to rupture. The results of the randomized controlled trials ADSORB and INSTEAD-XL have shown that beneficial aortic remodelling occurs after endoluminal stent graft placement, but these trials were underpowered to show any effect on survival. Static computed tomography (CT) angiography imaging methods have been used to try to identify high risk patients using parameters such as diameter, the position and size of the entry tear, and the amount of false lumen thrombus, but these so far are not able to clinically risk stratify individual patients. In this manuscript, we present our initial experience with new MR imaging methods. These have allowed us to develop a greater understanding of aortic dissection by providing information regarding the underlying hemodynamic and biomechanics of the dissection, as well as more accurate assessment of important clinical imaging endpoints, such as false lumen thrombosis.

Predicting aortic enlargement in type B aortic dissection

Patients with uncomplicated acute type B aortic dissection (ABAD) can generally be treated with conservative medical management. However, these patients may develop aortic enlargement during follow-up, with the risk of rupture. Several predictors have been studied in recent years to identify ABAD patients at high risk of aortic enlargement, who may benefit from early surgical or endovascular intervention. This study reviewed and summarized the current available literature on prognostic variables related to aortic enlargement during follow-up in uncomplicated ABAD patients. It revealed multiple factors affecting aortic expansion including demographic, clinical, pharmacologic and radiologic variables. Such predictors may be used to identify those ABAD patients at higher risk for aortic enlargement who may benefit from closer radiologic surveillance or early endovascular intervention. This approach deserves even more consideration because a significant number of patients develop aneurysmal degeneration along the dissected segments during follow-up, and may lose the opportunity for endovascular treatment if not identified at an early stage.

A perspective review on numerical simulations of hemodynamics in aortic dissection

Aortic dissection, characterized by separation of the layers of the aortic wall, poses a significant challenge for clinicians. While type A aortic dissection patients are normally managed using surgical treatment, optimal treatment strategy for type B aortic dissection remains controversial and requires further evaluation. Although aortic diameter measured by CT angiography has been clinically used as a guideline to predict dilation in aortic dissection, hemodynamic parameters (e.g., pressure and wall shear stress), geometrical factors, and composition of the aorta wall are known to substantially affect disease progression. Due to the limitations of cardiac imaging modalities, numerical simulations have been widely used for the prediction of disease progression and therapeutic outcomes, by providing detailed insights into the hemodynamics. This paper presents a comprehensive review of the existing numerical models developed to investigate reasons behind tear initiation and progression, as well as the effectiveness of various treatment strategies, particularly the stent graft treatment.

Conservative management of chronic aortic dissection with underlying aortic aneurysm

Aortic dissection is one of the most common aortic emergencies affecting around 2000 Americans each year. It usually presents in the acute state but in a small percentage of patients aortic dissections go unnoticed and these patients survive without any adequate therapy. With recent advances in medical care and diagnostic technologies, aortic dissection can be successfully managed through surgical or medical options, consequently increasing the related survival rate. However, little is known about the optimal long-term management of patients suffering from chronic aortic dissection. The purpose of the present report is to review aortic dissection, namely its pathology and the current diagnostic tools available, and to discuss the management options for chronic aortic dissection. We report a patient in which chronic aortic dissection presented with recurring episodes of vomiting and also discuss the management plan of our patient who had a chronic aortic dissection as well as an underlying aortic aneurysm.

Acute aortic syndromes

Acute aortic syndrome is a term that describes one of a number of different pathologic entities. Each of these conditions requires urgent or emergent evaluation and may possibly require surgical intervention. However, both entities may be unfamiliar to the nonsurgical (and in some cases, surgical) practitioner and they may mimic more common diseases or be missed entirely. An understanding of the processes, nomenclature, and management options is critical in optimizing patient care.

Long-Term Outcome of Aortic Dissection With Patent False Lumen

Background—

Patent false lumen in aortic dissection has been associated with poor prognosis. We aimed to assess the natural evolution of this condition and predictive factors.

Methods and Results—

One hundred eighty-four consecutive patients, 108 surgically treated type A and 76 medically treated type B, were discharged after an acute aortic dissection with patent false lumen. Transesophageal echocardiography was performed before discharge, and computed tomography was performed at 3 months and yearly thereafter. Median follow-up was 6.42 years (quartile 1 to quartile 3: 3.31–10.49). Forty-nine patients died during follow-up (22 type A, 27 type B), 31 suddenly. Surgical or endovascular treatment was indicated in 10 type A and 25 type B cases. Survival free from sudden death and surgical-endovascular treatment was 0.90, 0.81, and 0.46 (95% CI, 0.36–0.55) at 3, 5, and 10 years, respectively. Multivariate analysis identified baseline maximum descending aorta diameter (hazard ratio [HR]: 1.32 [1.10–1.59]; P =0.003), proximal location (HR: 1.84 [1.06–3.19]; P =0.03), and entry tear size (HR: 1.13 [1.08–1.2]; P <0.001) as predictors of dissection-related adverse events, whereas mortality was predicted by baseline maximum descending aorta diameter (HR: 1.36 [1.08–1.70]; P =0.008), entry tear size (HR: 1.1 [1.04–1.16]; P =0.001), and Marfan syndrome (HR: 3.66 [1.65–8.13]; P =0.001).

Conclusions—

Aortic dissection with persistent patent false lumen carries a high risk of complications. In addition to Marfan syndrome and aorta diameter, a large entry tear located in the proximal part of the dissection identifies a high-risk subgroup of patients who may benefit from earlier and more aggressive therapy.

Thoracic EndoVascular Stent Graft Repair for Aortic Aneurysm

BACKGROUND

The number of cases employing thoracic endovascular aortic repair (TEVAR) has been increasing due to lower morbidity and mortality compared to open repair technique. The aim of this study is to evaluate the outcome of TEVAR for thoracic aortic diseases.

MATERIALS AND METHODS

Sixteen patients underwent TEVAR from October 2003 to April 2010. Mean age at operation was 59 years (20~78 years), and 11 were male. Indications for TEVAR were large aortic diameter (>5.5 cm) upon presentation in 6 patients, increasing aortic diameter during the follow-up period in 4, traumatic aortic rupture in 3, persistent chest pain in 2, and ruptured aortic aneurysm in one. The mean diameter, length and the number of the stents were 33 mm (26~40 mm), 12 cm (9.5~16.0 cm), and 1.25 (1~2), respectively. Aortography employing Multi-detector computerized tomography (MDCT) technique was performed at one week, and patients were followed up in the out-patient department at one month, 6 months, and one year postoperatively.

RESULTS

Primary technical success showing complete exclusion of the aneurysm was achieved in 15 patients. One patient showed a small endo-leak (type 1). Four patients developed perioperative stroke: Three recovered without sequelae, and one showed mild right-side weakness. There was no operative mortality. Diameter of the thoracic aorta covered by stent graft changed within 10% range in 12 patients, decreased by more than 10% in 3, and increased by more than 10% in one during mean follow-up duration of 18 months (1~73 months). There was no recurrence-related death during this period.

CONCLUSION

Intermediate-term outcome after TEVAR was encouraging. Indications for TEVAR could be extended for other thoracic aortic diseases.

Effect of chronic dissection on early and late outcomes after descending thoracic and thoracoabdominal aneurysm repair

OBJECTIVE

Although chronic aortic dissection (CD) has traditionally been considered a predictor of perioperative morbidity and mortality after descending thoracic/thoracoabdominal aneurysm repair (thoracoabdominal aortic aneurysm [TAA]), recent reports have rejected this assertion. Still, few contemporary studies document late outcomes after TAA for CD, which is the goal of this study.

METHODS

From August 1987 to December 2005, 480 patients underwent TAA; 73 (15%) CD and 407 (85%) degenerative aneurysms (DA). Operative management consisted of a clamp-and-sew technique with adjuncts in 53 (78%) CD and 355 (93%) DA patients (P < .001). Epidural cooling was used to prevent spinal cord injury (SCI) in 51 (70%) CD and 214 (53%) DA patients (P = .007). Study end points included perioperative SCI/mortality, freedom from reintervention, and long-term survival.

RESULTS

CD patients were younger (mean age 64.5 years CD vs 72.5 years DA, P < .001) and more frequently had a family history of aneurysmal disease (23% CD vs 6% DA, P < .001). Forty-three (59%) CD patients had elective TAA (vs 322 (79%) DA, P = .001). Eleven (15%) CD patients had Marfan's syndrome (vs 0% DA, P < .001), and 17 (23%) CD patients had a prior arch or ascending aortic repair (vs 16 [4%] DA, P < .001). CD patients were more likely to have Crawford type I & II thoracoabdominal aneurysms (44 [60%] vs 120 [29%] DA, P < .001), while only two (3%) CD patients had type IV aneurysms (vs 99 [24%] DA). There was no difference in perioperative mortality between the two groups (11% CD vs 8.6% DA, P = .52), nor was there a difference in flaccid paralysis, which occurred in five (7%) CD and 22 (5%) DA patients (P = .92). At 5 years, 70% of CD patients were free from reintervention versus 74% of DA (P = .36). The actuarial survival was 53% and 32% at 5 and 10 years for CD versus 47% and 17% for DA (P = .07).

CONCLUSIONS

Despite increased operative complexity, CD does not appear to increase perioperative SCI or mortality after TAA when compared with DA. Long-term freedom from aneurysm-related reintervention is similar for both groups as is survival, despite patients with CD being of younger age at presentation.

Current strategy of endovascular aortic repair for thoracic aortic aneurysms

Thoracic aortic aneurysms are extremely burdensome to treat owing to their surgical complexity. In particular, major postoperative complications lower significantly patients' quality of life. Surgical treatment has recently shifted to thoracic endovascular aortic repair (TEVAR) to respect the patients' needs and improve postoperative quality of life. This procedure is radical and innovated for thoracic aortic pathology, but the devices and the delivery systems are immature because only a little over a decade and a half has passed since starting to use them. Ready-made stent-grafts were originally indicated only for degenerated aortic aneurysms, but aortic dissection and traumatic aortic transection will become the next targets for TEVAR. This review addresses the history and changes in TEVAR as well as the current TEVAR strategy. Finally, we describe a new trial of TEVAR for aortic dissections, traumatic aortic transections, and aortic arch aneurysms.