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Lou et al. Vessel Plus 2022;6:38 https://dx.doi.org/10.20517/2574-1209.2021.108 Page 5 of 9

Visceral/mesenteric malperfusion
While rare, visceral/mesenteric malperfusion is the most challenging and devastating variant of all the
malperfusion syndromes. It is associated with a 3- to 4-fold increase in mortality in both type A and B aortic
dissections, resulting in a mortality rate of 70%-100% . In an initial IRAD analysis of 464 patients with
[14]
[15]
ATAAD, the most common cause of death after aortic rupture was MMP .
The traditional strategy for management has been central aortic repair followed by a period of expectant
management with return to the operating room for exploratory laparotomy and possible bowel resection if
clinically indicated. Unfortunately, while central aortic repair restores true lumen flow and resolves dynamic
malperfusion, branch vessel ischemia can persist in 25% of patients due to the presence of distal re-entry
tears, persistent false lumen flow, and static branch vessel involvement . This strategy is associated with an
[16]
operative mortality of 40%-75% and has recently undergone increasing scrutiny in the literature .
[14]
In a subsequent IRAD analysis of 1809 consecutive patients with ATAAD presenting to 18 referral centers
[12]
worldwide from 1995 to 2010, the incidence of MMP was 3.8% (n = 68) . Notably, these patients were
critically ill and more likely to be older, present with coma, cerebrovascular accident, spinal cord ischemia,
acute renal failure, limb ischemia, and any kind of pulse deficit. Hospital mortality was 63.2% in those with
mesenteric malperfusion syndrome vs. 23.8% without (P < 0.001). Of the 502 patients undergoing
immediate surgery, 12 had MMP. The in-hospital mortality was 15% without malperfusion syndrome and
70% for patients with MMP. Moreover, MMP was identified as an independent predictor of in-hospital
mortality on multivariate analysis (OR = 2.5, 95%CI: 1.2-5.6). In patients with MMP, mortality was 95.2%
after medical management (n = 21), 72.7% after endovascular therapy alone, 41.7% after an open surgical or
hybrid approach (P < 0.001).

Other recent analyses have also suggested that central repair alone is insufficient to salvage these critically ill
patients. In an analysis of a Japanese database by Kawahito et al. of 1026 ATAAD patients undergoing
[17]
emergency central aortic repair, mortality was higher for those with an increased number of organ systems
affected: from 4.8% with 0 systems to 30.0% with 3 systems. In patients with malperfusion syndrome, obesity
(BMI > 30), preoperative shock (SBP < 80 mmHg), and MMP were independent predictors for hospital
death .
[17]

Given these poor outcomes with emergent central aortic repair for ATAAD with MMP, there has been an
emerging interest in the role of endovascular therapy.

INFLUENCE FROM ACUTE TBAD TREATMENT - THE EVOLVING ROLE OF
ENDOVASCULAR APPROACHES IN ATAAD MANAGEMENT
TEVAR in acute TBAD with malperfusion syndrome
In complicated acute TBAD patients with malperfusion syndrome of visceral/mesenteric vessels as well as
the lower extremities, TEVAR is now considered the gold standard. TEVAR relieves true lumen
compression as the endograft expands against a compliant dissection septum in the descending thoracic or
abdominal aorta, mitigating malperfusion related to the dynamic flap and re-establishing flow to the visceral
vascular beds as well as downstream lower extremities. Additionally, there is growing evidence that TEVAR
in the acute phase of TBAD improves aortic remodeling as well as long-term aortic-specific survival.

In comparison to optimal medical therapy and open surgery with an associated in-hospital mortality of
30%-35% , TEVAR has dramatically decreased early mortality in acute complicated TBAD patients with
[15]
low in-hospital mortality rates of 0%-8% [18-20] . One of the initial reports of TEVAR for complicated TBAD by