Abstract
Background
The optimal initial management for uncomplicated acute type B aortic dissection (uATBAD) remains unclear. We evaluated 1-year aortic remodeling and clinical outcomes of thoracic endovascular aortic repair (TEVAR) vs exclusively optimal medical therapy for uATBAD.
Methods
Patients with uATBAD were retrospectively grouped by initial treatment modality, with 52 patients treated with TEVAR and 142 with optimal medical therapy. Clinical outcomes and aortic remodeling were compared at presentation and 1-year follow-up. Aortic remodeling parameters, including change in true lumen diameter, full lumen diameter, and true lumen index, and extent of false lumen thrombosis were assessed at 12 thoracoabdominal levels and compared between treatment groups.
Results
TEVAR had lower 30-day/in-hospital mortality than optimal medical therapy (0% vs 11.3%; P < .01). Reintervention rates did not differ between groups (P > .05). Thirty-one TEVAR and 42 optimal medical therapy patients were included in remodeling analysis with a median follow-up of 6.9 months (interquartile range, 3.6-10.8 months). Change in true lumen diameter and true lumen index was greater in TEVAR than in optimal medical therapy from left subclavian artery to the diaphragm (P < .001). Change in full lumen diameter showed no difference between groups except at the superior mesenteric artery (P = .04). At the thoracic aortic levels, TEVAR showed significant shift toward full false lumen thrombosis (P < .001).
Conclusions
TEVAR was associated with favorable aortic remodeling as well as short-term and midterm outcomes compared with optimal medical therapy in patients with uATBAD. The positive remodeling is more pronounced at thoracic aortic levels.
Visual Abstract
In Short.
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Thoracic endovascular aortic repair may render improved aortic remodeling in uncomplicated acute type B dissection compared with medical therapy.
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Thoracic endovascular aortic repair has short-term clinical outcomes equal to or better than those of medical therapy in uncomplicated acute type B dissection.
Thoracic aortic dissections are associated with substantial morbidity and mortality worldwide.1 Whereas thoracic endovascular aortic repair (TEVAR) has been established as the primary treatment strategy for patients with complicated type B aortic dissection, the best treatment approach for uncomplicated presentation is still evolving.1,2
Optimal medical therapy (OMT) alone has traditionally been the standard of care for patients with uncomplicated acute type B aortic dissection (uATBAD).2 However, growing evidence suggests that it may lead to aneurysmal instability, requiring open aortic intervention during the chronic phase.3 Therefore, TEVAR with medical therapy is being increasingly considered for uATBAD, especially in patients presenting with high-risk radiologic features.4
Positive aortic remodeling in type B aortic dissection is an important factor in the efficacy of TEVAR vs OMT.5 In this single-institutional study, we aimed to compare clinical and aortic remodeling outcomes at 1 year in patients with uATBAD treated with TEVAR and medical therapy vs exclusively with OMT.
Material and Methods
Study Population
The electronic health records of patients presenting with uATBAD (defined by the Society for Vascular Surgery and The Society of Thoracic Surgeons reporting standards for type B aortic dissections6) from July 1992 to February 2023 were included in the study. Patients were grouped by initial intervention: TEVAR, if treated with TEVAR and medical therapy; or OMT, if treated exclusively with medical therapy. Patient demographics, comorbidities, and clinical outcomes were collected from medical records (Supplemental Methods).
Assessment of Aortic Remodeling on Thoracoabdominal Aorta
Patients with imaging available at presentation and 1-year follow-up were included in aortic remodeling analysis. Aortic remodeling parameters including true lumen diameter (TLD), full lumen diameter (FLD), and true lumen index (TLi), defined as the ratio of TLD to FLD, were measured at 12 thoracoabdominal levels by previously validated methodology.7 Extent of false lumen thrombosis was categorized as full thrombosis if only thrombus was observed, partial thrombosis if both thrombus and contrast material were observed, or patent if only evidence of contrast material was observed. Perfusion of visceral vessels was recorded as coming from the false lumen, true lumen, or both.
Statistical Analysis
Analyses were performed with R version 4.1.1 (R Foundation for Statistical Computing). Categorical variables are presented as frequency with percentages and compared by Pearson χ2 or Fisher exact test. Normal distribution of continuous variables was assessed by Shapiro-Wilk test and further analyzed with Student t-test or Mann-Whitney U test. Analysis of covariance was used to account for the number of days between initial and 1-year scans as a covariate in comparing the change in diameter or index between treatment groups. Significance threshold was P < .05. For initially significant results in analysis of false lumen thrombosis between initial and 1-year scans, post hoc analysis with Fisher exact test was performed by the Bonferroni method for P value adjustment.
Results
Study Population
A total of 194 patients were included in clinical analysis, with 52 triaged to treatment with TEVAR and 142 to OMT. The overall study cohort’s mean age was 64.6 ± 14.5 years, with most patients having a comorbidity diagnosis of hypertension (72.7%). The TEVAR group contained more patients with hypertension (86.5% vs 67.6%; P = .01) and medical history of smoking (59.6% vs 40.8%; P = .03) than the OMT group (Table 1).
Table 1.
Patient Demographics and Clinical Outcomes
| Variable | All |
OMT |
TEVAR |
P Value |
|---|---|---|---|---|
| (N = 194) | (n = 142) | (n = 52) | ||
| Baseline demographics | ||||
| Age, y | 64.6 (14.5) | 64.4 (15.1) | 65.3 (12.6) | .66 |
| Female | 75 (38.7) | 60 (42.3) | 15 (28.8) | .13 |
| Body mass index, kg/m2 | 29.6 (8.6) | 29.2 (8.1) | 30.5 (9.8) | .41 |
| Hypertension | 141 (72.7) | 96 (67.6) | 45 (86.5) | .01 |
| Smoking | 89 (45.9) | 58 (40.8) | 31 (59.6) | .03 |
| Dyslipidemia | 70 (36.1) | 45 (31.7) | 25 (48.1) | .05 |
| Diabetes | 25 (12.9) | 15 (10.6) | 10 (19.2) | .18 |
| Myocardial infarction | 13 (6.7) | 11 (7.7) | 2 (3.8) | .52 |
| Coronary artery disease | 34 (17.5) | 22 (15.5) | 12 (23.1) | .31 |
| Chronic kidney disease | 26 (13.4) | 18 (12.7) | 8 (15.4) | .80 |
| Cerebrovascular accident | 18 (9.3) | 11 (7.7) | 7 (13.5) | .35 |
| Postintervention outcomes | ||||
| 30-day mortality | 16 (8.2) | 16 (11.3) | 0 (0) | .007 |
| 30-day reintervention | 27 (13.9) | 23 (16.2) | 4 (7.7) | .16 |
| 6-month follow-up | ||||
| Stroke | 9 (4.6) | 8 (5.6) | 1 (1.9) | .28 |
| Paraplegia | 3 (1.5) | 3 (2.1) | 0 (0) | .55 |
| Renal failure | 17 (8.8) | 16 (11.3) | 1 (1.9) | .02 |
| Sepsis | 4 (2.1) | 3 (2.1) | 1 (1.9) | >.99 |
| Malperfusion | 12 (6.2) | 12 (8.5) | 0 (0) | .02 |
| 2-year mortality | 37 (19.1) | 33 (23.2) | 4 (7.7) | .01 |
| 2-year reintervention | 74 (38.1) | 58 (40.8) | 16 (30.8) | .27 |
Data are presented as mean (SD) or frequency (% of total).
OMT, optimal medical therapy; TEVAR, thoracic endovascular aortic repair.
Clinical Outcomes
The 30-day/in-hospital mortality was 0% in the TEVAR group and 11.3% in OMT (P < .01). TEVAR showed lower mortality rates than OMT at 2 years (7.7% vs 23.2%, P = .01) and no difference in reintervention rates (30.8% vs 40.8%; P = .27). At 6-month follow-up, TEVAR patients had lower rates of renal failure (1.9% vs 11.3%; P = .02) and malperfusion (0% vs 8.5%; P = .02) than OMT patients (Table 1).
Aortic Remodeling
A total of 73 patients had comprehensive imaging data for analysis of aortic remodeling, of whom 31 underwent TEVAR and 42 received OMT. The median radiologic follow-up between the groups did not statistically differ (OMT, 9.0 months [interquartile range, 3.8-11.9 months]; TEVAR, 5.9 months [interquartile range, 2.9-9.9 months]; P = .09; Supplemental Table 1). Initial measurements of FLD and TLD before intervention are shown in Supplemental Table 2.
Aortic remodeling changes for the TLD, FLD, and TLi are presented in Supplemental Tables 3 and 4. We observed a greater increase in TLD for patients undergoing TEVAR than for those receiving OMT at the thoracoabdominal levels of the left subclavian artery (6.5 mm vs −0.4 mm; P < .001), carina (8.5 mm vs 0.6 mm; P < .001), left inferior pulmonary vein (9.4 mm vs 0.4 mm; P < .001), left atrium (8.0 mm vs −0.2 mm; P < .001), and diaphragm (6.7 mm vs −0.8 mm; P < .001; Figure 1A).
Figure 1.
Change in (A) true lumen diameter, (B) full lumen diameter, and (C) true lumen index at 1 year, by thoracoabdominal level. (OMT, optimal medical therapy; TEVAR, thoracic endovascular aortic repair.)
The changes in FLD did not statistically differ between the groups except at the level of the superior mesenteric artery, where there was a greater increase in diameter in OMT vs TEVAR (2.4 mm vs 0.6 mm; P = .04; Supplemental Table 3; Figure 1B). There was a significantly greater increase in TLi for TEVAR than for OMT at the thoracoabdominal levels of the left subclavian artery (0.11 vs −0.03; P < .001), carina (0.16 vs 0.00; P < .001), left inferior pulmonary vein (0.18 vs 0.0; P < .001), left atrium (0.16 vs −0.03; P < .001), diaphragm (0.12 vs −0.06; P < .001), and superior mesenteric artery (0.05 vs −0.02; P = .04; Supplemental Table 4; Figure 1C).
TEVAR improved false lumen full thrombosis in the thoracic aorta from 29% (9/31) to 74.2% (23/31) during the study period (Table 2; Figure 2). TEVAR did not show significant changes in false lumen thrombosis in the abdominal aorta. No significant changes in false lumen thrombosis in the thoracic and abdominal aorta were observed with OMT (Table 2; Figure 2).
Table 2.
False Lumen Thrombosis by Aortic Level
| Aortic Level | OMT (n = 42) |
TEVAR (n = 31) |
||||
|---|---|---|---|---|---|---|
| Initial Scan | 1 Year | P Value | Initial Scan | 1 Year | P Value | |
| Thoracic aorta | .42 | <.001 | ||||
| Full thrombosis | 4 (9.5) | 7 (16.7) | 9 (29) | 23 (74.2) | ||
| Partial thrombosis | 11 (26.2) | 7 (16.7) | 8 (25.8) | 7 (22.6) | ||
| Patent | 27 (64.3) | 28 (66.7) | 14 (45.2) | 1 (3.2) | ||
| Abdominal aorta | .80 | .60 | ||||
| Full thrombosis | 5 (11.9) | 5 (11.9) | 6 (19.4) | 10 (32.3) | ||
| Partial thrombosis | 3 (7.1) | 5 (11.9) | 8 (25.8) | 6 (19.4) | ||
| Patent | 34 (81) | 32 (76.2) | 17 (54.8) | 15 (48.4) | ||
Data are presented as n (% of total). Post hoc analysis, with P value adjustment by the Bonferroni method, was conducted for initially significant values.
OMT, optimal medical therapy; TEVAR, thoracic endovascular aortic repair.
Figure 2.
False lumen thrombosis status for thoracic endovascular aortic repair (TEVAR) and optimal medical therapy (OMT) in (A) thoracic aorta and (B) abdominal aorta.
Visceral vessel perfusion status was not significantly altered between the time points for any treatment group or vessel (Supplemental Table 5 and Supplemental Figure 1).
Comment
In this study, we investigated the comparative efficacy of TEVAR vs OMT in the treatment of uATBAD. Our analysis showed that TEVAR had significantly reduced 30-day/in-hospital and 2-year mortality compared with OMT. At 6 months, TEVAR showed fewer rates of malperfusion and renal failure than OMT. Moreover, superior aortic remodeling was observed with TEVAR, including false lumen thrombosis and increases in TLD and TLi, especially at thoracic levels from the left subclavian artery to the diaphragm.
The degree of aortic remodeling after dissection is an important determinant of long-term prognosis of patients and further need for surgical intervention.8 Lou and coworkers9 showed that in uATBAD, maximum aortic diameter did not differ at follow-up between TEVAR and OMT and that false lumen status favored TEVAR over OMT. Our study confirms these remodeling findings while delineating the specific thoracoabdominal levels at which TEVAR markedly surpassed OMT and supplementing with lumen-specific measurements. These data further bolster the evolving evidence favoring TEVAR for the management of both complicated type B aortic dissection and uATBAD.
The safety benefit of OMT was highlighted by the International Registry of Acute Aortic Dissection database study, in which patients had a 10.7% 30-day mortality.10 This study was performed in the era of OMT vs open surgical repair. We found 30-day/in-hospital mortality to be 0% with TEVAR and 11.3% with OMT. In addition, 2-year mortality was higher in the OMT group along with rates of renal failure and malperfusion at 6 months. This suggests that the improved aortic remodeling achieved with TEVAR may have contributed to the superior clinical outcomes compared with OMT. These findings are supported by the prospective, randomized ADSORB trial, which found improved remodeling with TEVAR management compared with medical therapy alone but no difference in mortality at 1 year.5
This study’s retrospective, single-center, and small population design may limit its generalizability to other institutions and power to detect differences between study groups. Throughout this study period, the efficacy and safety of TEVAR technology have significantly changed, which may have influenced the decision-making behind treatment plans for patients and their outcomes. In addition, our limited follow-up period limits our ability to evaluate long-term remodeling.
In conclusion, TEVAR promoted more favorable aortic remodeling than OMT for uATBAD, predominantly at the thoracic aortic levels. These findings further support more integration of TEVAR in the initial treatment paradigm for uATBAD.
Acknowledgments
The Supplemental Material can be viewed in the online version of this article [https://doi.org/10.1016/j.atssr.2025.01.012] on https://www.annalsthoracicsurgeryshortrep.org.
The study was approved by the Yale University institutional review board on March 2, 2017, with last update on August 27, 2024 (IRB #2000020356).
Funding Sources
Adrian Acuna Higaki reports financial support was provided by National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health under Award No. T35DK104689.
Disclosures
Prashanth Vallabhajosyula reports a relationship with Terumo Aortic that includes: consulting or advisory; and with Medtronic Aortic that includes: consulting or advisory. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
Footnotes
Presented as an ePoster at the Sixty-first Annual Meeting of The Society of Thoracic Surgeons, Los Angeles, CA, Jan 24-26, 2025.
Supplementary Data
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