Current Experience With Acute Type B Aortic Dissection: Validity of the Complication-Specific Approach in the Present Era

Five-Year Results of Aortic Remodeling for Acute, Subacute, and Chronic Type B Aortic Dissection Following Endovascular Repair

Background

This study was performed to compare aortic remodeling and clinical outcomes in patients with acute, subacute, and chronic type B aortic dissection (TBAD) after thoracic endovascular aortic repair (TEVAR).

Methods

We retrospectively examined 323 consecutive patients with acute (n = 129), subacute (n = 161), and chronic (n = 33) TBAD who underwent TEVAR from June 2013 to December 2016 in in multicenter institution. Patient demographics, clinical data, and imaging characteristics were recorded and compared among the three groups.

Results

The three groups had comparable baseline characteristics. Perioperative mortality rates were similar among the acute (2.3%), subacute (0.0%), and chronic (0.0%) groups (P = 0.34). Perioperative morbidity rates, including the rates of visceral and lower limb malperfusion and cerebral infraction, were also similar. The rate of perioperative endoleak was significantly higher in the chronic group (18.1%) than in the acute (3.9%) and subacute (3.7%) groups (P = 0.02). The mean follow-up duration was 78 ± 22 months (range, 36–101 months). The mortality rates were comparable among the three groups. The rates of reintervention and lower limb malperfusion were higher in the chronic group than in the acute and subacute groups. FL diameter reduction were more robust in the acute and subacute groups than in the chronic group.

Conclusion

Patients with acute, subacute, and chronic TBAD had different outcomes in this study. Patients with acute and subacute TBAD had fewer complications than those with chronic TBAD. Aortic remodeling after TEVAR was more favorable in patients with acute and subacute TBAD than in patients with chronic TBAD. TEVAR promotes more positive remodeling at the stent graft level than at the distal level of the aorta.

Imaging and Surveillance of Chronic Aortic Dissection: A Scientific Statement From the American Heart Association

All patients surviving an acute aortic dissection require continued lifelong surveillance of their diseased aorta. Late complications, driven predominantly by chronic false lumen degeneration and aneurysm formation, often require surgical, endovascular, or hybrid interventions to treat or prevent aortic rupture. Imaging plays a central role in the medical decision-making of patients with chronic aortic dissection. Accurate aortic diameter measurements and rigorous, systematic documentation of diameter changes over time with different imaging equipment and modalities pose a range of practical challenges in these complex patients. Currently, no guidelines or recommendations for imaging surveillance in patients with chronic aortic dissection exist. In this document, we present state-of-the-art imaging and measurement techniques for patients with chronic aortic dissection and clarify the need for standardized measurements and reporting for lifelong surveillance. We also examine the emerging role of imaging and computer simulations to predict aortic false lumen degeneration, remodeling, and biomechanical failure from morphological and hemodynamic features. These insights may improve risk stratification, individualize contemporary treatment options, and potentially aid in the conception of novel treatment strategies in the future.

Successful surgical repair of traumatic aortic dissection utilizing the Najuta stent graft in a patient with pre-existing situs inversus and anomalous neck vessels

We report the case of a 39-year-old man who underwent surgical repair for traumatic Stanford type B acute aortic dissection. He was involved in a traffic accident, resulting in multiple rib fractures and a sternum fracture. On investigation, he was also found to have anatomical anomalies, namely, situs inversus and abnormality in the aortic arch and neck vessels. Thoracic endovascular aortic repair was performed as it is a less invasive procedure, thus recommended in such cases. A fenestrated thoracic endovascular aortic repair using the Najuta stent graft was found to be effective in this case where the anomalous anatomy was pre-existing.

TEVAR for complicated and uncomplicated type B aortic dissection-Systematic review and meta-analysis

BACKGROUND

Type B aortic dissection (TBAD), is defined as a dissection involving the aorta distal to left subclavian artery with the ascending aorta and the aortic arch not affected. TBAD is classified due to the time frame and presence of complications. Complicated TBAD (co-TBAD) patients have a greater mortality rate than uncomplicated TBAD (un-TBAD) and thoracic endovascular aortic repair (TEVAR) is considered the gold-standard intervention for these clinical challenges.

METHODS

We undertook a systematic review of the literature regarding TEVAR intervention in co-TBAD and un-TBAD. A comprehensive search was undertaken across four major databases and was evaluated and assessed until June 2020.

RESULTS

A total of 16,104 patients were included in the study (7772 patients co-TBAD and 8352 un-TBAD). A significantly higher proportion of comorbidities were seen in co-TBAD patients compared with un-TBAD. Acute dissection was more frequent in the co-TBAD group (73.55% vs. 66.91%), while chronic dissection was more common in un-TBAD patients (33.8% vs. 70.73%). Postprocedure stroke was higher in co-TBAD (5.85% vs. 3.92%; p < .01), while postprocedural renal failure was higher in un-TBAD patients (7.23 vs. 11.38%; p < .01). No difference was observed in in-hospital mortality however the 30 days mortality was higher in the co-TBAD group. One-year survival was higher in the uncomplicated group but this difference was not observed in the 5-year survival.

CONCLUSION

In our analysis we can appreciate that despite significantly higher comorbidities in the co-TBAD cohort, there was no difference in in-hospital mortality between the two groups and the 5-year survival did not have any difference.

Time is of the essence: where can we improve care in acute aortic dissection?

OBJECTIVES

In acute aortic dissection type A various components of the diagnostic and logistic pathways may affect the time to definitive treatment. This study aimed to characterize these components and to identify factors delaying the optimal management within our institutional referral network.

METHODS

Between January 2017 and January 2020, 96 consecutive patients with classical aortic dissection type A were admitted (28%) or referred (72%) to our tertiary care centre and analysed retrospectively. Data are presented as medians (25th-75th quartile).

RESULTS

Median age was 66 years (56-74), 63% were male. Most of the patients were primarily admitted to a cardiology department (40%), whereas about a fourth were admitted to departments for internal medicine (26%) and general surgery (27%). The median interval from the onset of symptoms to hospital admission was 2.1 (1-4.4) h. From admission to confirmed diagnosis it took 2.1 (0.6-9.5) h and the median interval from confirmed diagnosis to admission at our specialized tertiary care aortic centre was 1.5 (0.9-2.4) h. Following admission to our centre, 1.1 (0.5-1.9) h passed until the induction of anaesthesia and 0.8 (0.0-1.1) h until the start of surgery. The total interval from the onset of symptoms to the start of surgery was 7.6 h (5.1-12.3).

CONCLUSIONS

The marked variability of the time from symptoms to diagnosis at any medical facility demonstrates the importance of awareness in the optimization of the treatment of acute aortic dissection type A.

Cause-specific mortality of type B aortic dissection and assessment of competing risks of mortality

OBJECTIVE

Natural history studies of type B aortic dissection (TBAD) commonly report all-cause mortality. Our aim was to determine cause-specific mortality in TBAD and to evaluate the clinical characteristics associated with aorta-related and nonaorta-related mortality.

METHODS

Clinical and administrative records were reviewed for patients with acute TBAD between 1995 and 2017. Demographics, comorbidities, presentation, and initial imaging findings were abstracted. Cause of death was ascertained through a multimodality approach using electronic health records, obituaries, social media, Social Security Death Index, and state mortality records. Causes of death were classified as aorta related, nonaorta related, or unknown. A Fine-Gray multivariate competing risk regression model for subdistribution hazard ratio was employed to analyze the association of clinical characteristics with aorta-related and nonaorta-related mortality.

RESULTS

A total of 275 individuals met inclusion criteria (61.1 ± 13.7 years, 70.9% male, 68% white). Mean survival after discharge was 6.3 ± 4.7 years. Completeness of follow-up Clark C index was 0.87. All-cause mortality was 50.2% (n = 138; mean age, 70.1 ± 14.6 years) including an in-hospital mortality of 8.4%. Cause-specific mortality was aorta related, nonaorta related, and unknown in 51%, 43%, and 6%, respectively. Compared with patients with nonaorta-related mortality, patients with aorta-related mortality were younger at acute TBAD (69.5 ± 11.2 years vs 61.6 ± 15.5 years; P = .001), underwent more descending thoracic aortic repairs (19.4% vs 45.8%; P = .002), and had a shorter survival duration (5.7 ± 3.9 vs 3.4 ± 4.5 years; P = .002). There was clear variation in cause of death by each decade of life, with higher aorta-related mortality among those younger than 50 years and older than 70 years and a stepwise increase in nonaorta-related mortality with each increasing decade (P < .001). All-cause mortality at 1 year, 3 years, and 10 years was 15%, 24%, and 57%, respectively. After accounting for competing risks, the cumulative incidence of aorta-related mortality at 1 year, 3 years, and 10 years was 8.9%, 16.5%, and 27.2%, respectively, and that of nonaorta-related mortality was 2.7%, 7.2%, and 29%, respectively. A maximum descending thoracic aortic diameter >4 cm was associated with an increase in hazard of aorta-related mortality by 84% (subdistribution hazard ratio, 1.84; 95% confidence interval, 1.03-3.28) on multivariate competing risk regression analysis.

CONCLUSIONS

TBAD is associated with high 10-year mortality. Those at risk for aorta-related mortality have a clinical phenotype different from that of individuals at risk for nonaorta-related mortality. This information is important for building risk prediction models that account for competing mortality risks and to direct optimal and individualized surgical and medical management of TBAD.

Aortic Wall Enhancement Detected by Contrast Computed Tomography Scan Predicts Aortic Remodeling after Conservative Therapy for Acute Uncomplicated Type B Dissection

BACKGROUND

The Investigation of Stent Grafts in Aortic Dissection with extended length of follow-up trial showed that pre-emptive thoracic endovascular aneurysm repair (TEVAR) for the uncomplicated type B dissection (TBAD) in the subacute phase promotes aortic remodeling and avoids aortic-related death 5 years after onset. However, there are some patients with complete aortic remodeling (CAR) with optimal medical treatment (OMT) and severe complications after TEVAR such as retrograde type A dissection. Therefore, which patients should undergo pre-emptive TEVAR and optimal surgical timing are still under debate. We reported that aortic wall enhancement (AWE) after endovascular aneurysm repair for abdominal aortic aneurysm was associated with sac shrinkage. However, there is no report about the relationship between AWE and aortic dissection. Herein, we evaluated the relationship between AWE and acute TBAD.

METHODS

From March 2012 to May 2018, consecutive patients with acute TBAD were retrospectively collected. We retrospectively analyzed 35 patients with acute TBAD who were treated with OMT and without pre-emptive TEVAR in the subacute phase. AWE was defined as an increase of more than 20 Hounsfield units in mean computed tomography (CT) values, comparing images in delayed contrast-enhanced scans with those in plain scans evaluated within 3 months from onset. The measurement points were all slices including the wall of the false lumen. The patients with traumatic dissection, type A dissection, acute complicated type B dissection, chronic (>12 weeks) dissection, and those lost to follow-up within 3 months from onset were excluded. The primary end point was spontaneous CAR under OMT, as determined by the latest contrast-enhanced CT scan.

RESULTS

The median follow-up period from onset was 86 weeks and there were 25 cases (71.4%) with AWE. Under OMT, CAR was observed in 20 patients (57.1%); this was significantly associated with abdominal branch dissection (6/15 [40%] vs. 2/20 [10%], P = 0.050), number of tears more than 2 at onset (11/15 [73%] vs. 4/20 [20%], P = 0.003), multiple tears at 1 month after onset (9/15 [60%] vs. 4/20 [20%], P = 0.020), maximal false lumen diameter at 1 month after onset (14 vs. 8 mm, P = 0.025), and AWE within 3 months of onset (7/15 [47%] vs. 18/20 [90%], P = 0.010). Multivariate analysis demonstrated a significant difference with multiple tears at onset (P = 0.014) and AWE within 3 months of onset (P = 0.047).

CONCLUSIONS

AWE was associated with CAR under OMT for acute TBAD which is out of indication of pre-emptive TEVAR. Presence of AWE may be useful in predicting prognosis of TBAD.

Natural history of descending thoracic and thoracoabdominal aortic aneurysms

OBJECTIVES

Elucidating critical aortic diameters at which natural complications (rupture, dissection, and death) occur is of paramount importance to guide timely surgical intervention. Natural history knowledge for descending thoracic and thoracoabdominal aortic aneurysms is sparse. Our small early studies recommended repairing descending thoracic and thoracoabdominal aortic aneurysms before a critical diameter of 7.0 cm. We focus exclusively on a large number of descending thoracic and thoracoabdominal aortic aneurysms followed over time, enabling a more detailed analysis with greater granularity across aortic sizes.

METHODS

Aortic diameters and long-term complications of 907 patients with descending thoracic and thoracoabdominal aortic aneurysms were reviewed. Growth rates (instrumental variables approach), yearly complication rates, 5-year event-free survival (Kaplan-Meier), and risk of complications as a function of aortic height index (aortic diameter [centimeters]/height [meters]) (competing-risks regression) were calculated.

RESULTS

Estimated mean growth rate of descending thoracic and thoracoabdominal aortic aneurysms was 0.19 cm/year, increasing with increasing aortic size. Median size at acute type B dissection was 4.1 cm. Some 80% of dissections occurred below 5 cm, whereas 93% of ruptures occurred above 5 cm. Descending thoracic and thoracoabdominal aortic aneurysm diameter 6 cm or greater was associated with a 19% yearly rate of rupture, dissection, or death. Five-year complication-free survival progressively decreased with increasing aortic height index. Hazard of complications showed a 6-fold increase at an aortic height index of 4.2 or greater compared with an aortic height index of 3.0 to 3.5 (P < .05). The probability of fatal complications (aortic rupture or death) increased sharply at 2 hinge points: 6.0 and 6.5 cm.

CONCLUSIONS

Acute type B dissections occur frequently at small aortic sizes; thus, prophylactic size-based surgery may not afford a means for dissection protection. However, fatal complications increase dramatically at 6.0 cm, suggesting that preemptive intervention before that criterion can save lives.

Timely identification of atypical acute aortic dissection in the emergency department:a study from a tertiary hospital

Background/aim

Acute aortic dissection (AAD) is a rare but fatal disease if left untreated. Symptoms are often similar to common conditions; therefore, the diagnostic strategy is important. We aimed to identify the atypical symptoms in a timely manner without putting patients at greater risk for undetected AAD.

Materials and methods

We conducted a retrospective observational study of 59 AAD patients with both atypical and typical symptoms from January 2012 to December 2016. Patients with atypical symptoms continuing more than 30 min underwent a D-dimer test and computed tomography (CT) or computed tomographic angiography (CTA).

Results

Of the 59 AAD patients, 22 were atypical. In the atypical group, the median delay time in our hospital was 3.1 h; average delay time after July 2015 was shorter than average delay time before June 2015 (16.59 ± 24.70 vs. 1.90 ± 0.57 h, P = 0.076).

Conclusions

For patients in the emergency department who are suspected of having AAD, incorporating atypical symptoms with high levels of D-dimer into a triage strategy could improve the efficiency of clinical decision making. Furthermore, essential education directed towards the recognition of the atypical symptoms of AAD for front-line physicians may aid in a timely diagnosis, as compared with the usual assessments in the emergency department.

Suppressive effect of pitavastatin on aortic arch dilatation in acute stanford type B aortic dissection: analysis of STANP trial

OBJECTIVES

Medical therapy for patients with uncomplicated acute type B aortic dissection (ABAD) is essentially accepted for its excellent early outcome; however, long-term outcomes have not been satisfactory due to aorta-related complications. This trial was performed to investigate the efficacy of a statin as an additive that may enhance the effectiveness of conventional medical treatment in patients with ABAD.

METHODS

This was a multi-center, prospective, and randomized comparative investigation of patients with uncomplicated ABAD. Fifty patients with ABAD compatible with inclusion criteria were randomly assigned to two groups and then received administration of pitavastatin (group P) or not (group C). We followed up the patients for 1 year from study onset.

RESULTS

Two patients demised during the follow-up period (both were in group C). In addition, aorta-related interventions were performed in two patients (entry closure for aortic dissection by endovascular repair in one patient in each group). Aortic arch diameters at 1 year in group P tended to be smaller than in group C (P = 0.17), and the rate of change of the aortic arch diameters from onset to 1 year was significantly lower in group P (P = 0.046). Multivariate analysis identified patency of the false lumen was detected as a risk factor for aortic arch dilatation (P = 0.02), and pitavastatin intake was a negative risk factor (P = 0.03).

CONCLUSIONS

Pitavastatin treatment, in addition to the standard antihypertensive therapy, may have a suppressive effect on aortic arch dilatation in patients with ABAD.

Cluster analysis of acute ascending aortic dissection provides novel insight into mechanisms of distal progression

Background

Whether primary tear size impacts extent of type A dissection is unclear. Using statistical groupings based on dissection morphology, we examined its relationship to primary tear area.

Methods

We retrospectively reviewed 108 patients who underwent acute ascending dissection repair from 2000-2016. Dissection morphology was characterized using 3-dimensional (3D) reconstructions of computed tomography (CT) scan images. Two-step cluster analysis was performed to group the dissections by examining the true lumen area as a fraction of the total aortic area at various levels.

Results

Cluster analysis defined two distinct categories. This first grouping corresponds to DeBakey type I (n=71, 65.7%) with a dissection extending from the ascending aorta to the aortic bifurcation. The second grouping conforms more closely to DeBakey type II dissection (n=37, 34.3%). It differs however from the classic type II definition as the dissection may extend up to the distal arch from the ascending aorta. Compared to type I, this "extended" DeBakey type II had no malperfusion (P<0.05), a larger primary tear area (6.6 vs. 3.7 cm², P=0.009), and a greater burden of atherosclerotic coronary artery disease (P<0.05). A smaller aortic valve annulus (P=0.025) and a smaller root false lumen area (P=0.017) may explain less aortic valve insufficiency (P<0.05) in extended type II dissections. No differences in complications or survival were seen.

Conclusions

In this series, limited distal extension of DeBakey type II dissections appears to be related to a larger primary tear area and greater atherosclerotic disease burden. It is also associated with less malperfusion and aortic valve insufficiency.

Endovascular Repair in Acute Complicated Type B Aortic Dissection: 3-Year Results from the Valiant US Investigational Device Exemption Study

Acute complicated type B aortic dissection (TBAD) is a potentially catastrophic, life-threatening condition. If left untreated, there is a high risk of aortic rupture, irreversible organ or limb damage, or death. Several risk factors have been associated with acute complicated TBAD, including age and refractory hypertension. In the acute phase, even uncomplicated patients are more prone to develop complications if hypertension and pain are left medically untreated. Innovations in stent graft technologies have incrementally improved outcomes since their first use for this condition in 1999, though improvement is needed in mitigating periprocedural complications, adverse events, and mortality. In the past decade, endovascular repair has become the preferred treatment because of its superior outcomes to open repair and medical therapy. The Valiant Captivia Thoracic Stent Graft System is a third-generation endovascular stent graft with advancements in minimally invasive delivery, conformability to the anatomy, and the minimization of adverse sequelae. Herein, this stent graft is briefly reviewed and its 3-year outcomes are presented. Freedom from all-cause and dissection-related mortality was 79.1% and 90.0%, respectively. The Valiant Captivia Stent Graft represents a safe, effective intervention for acute complicated TBAD. Continued surveillance is needed to verify its longer-term durability.

Successful Treatment of Esophageal Necrosis Secondary to Acute Type B Aortic Dissection

Esophageal necrosis after descending aortic dissection has been described but with no reports of successful treatment. A 66-year-old man with aortic dissection extending from the left subclavian artery through the common iliac arteries subsequently experienced esophageal necrosis. He underwent thoracic esophagectomy, cervical end esophagostomy, and open gastrostomy tube placement. Gastrointestinal continuity was established with a gastric tube conduit in the substernal plane. An oral diet was tolerated after reconstruction. Treatment of esophageal necrosis after aortic dissection may require esophageal diversion and esophagectomy. Esophageal continuity can later be restored while avoiding the posterior mediastinum.