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\begin{document}

\title{Limited vs Extended Repair for Type A Aortic Dissection involving Aortic
Arch}



\author[1]{Matthew Henn}%
\author[2]{Marc Moon}%
\affil[1]{The Ohio State University Wexner Medical Center}%
\affil[2]{Washington University}%


\vspace{-1em}



  
  \date{June 14, 2024}


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\selectlanguage{english}
\begin{abstract}
Significant controversy exists in the management of type A aortic
dissections with aortic arch involvement. There is a substantial
variability in approaches to this complex problem ranging from simply
replacing the ascending aorta to total arch replacement with frozen
elephant trunk -- all of which balance the competing interests of
reducing operative risk and reducing risk of reintervention. The
diversity of clinical details, variability of surgical experience, and
lack of significant randomized data make a consensus approach to these
patients unlikely. However, it is important to understand the risks and
benefits of each technique, and herein we evaluate the outcomes of each.
Our approach to these patients has been to reserve arch replacement for
those who have arch aneurysmal disease, imminent risk of rupture, or
cerebral malperfusion, and perform a hemiarch replacement in all other
scenarios with arch involvement. Such approach is easily taught, safe,
and reproducible while focusing more on survival rather than long-term
freedom from reintervention.%
\end{abstract}%



\sloppy


\emph{Abstract}

Significant controversy exists in the management of type A aortic
dissections with aortic arch involvement. There is a substantial
variability in approaches to this complex problem ranging from simply
replacing the ascending aorta to total arch replacement with frozen
elephant trunk -- all of which balance the competing interests of
reducing operative risk and reducing risk of reintervention. The
diversity of clinical details, variability of surgical experience, and
lack of significant randomized data make a consensus approach to these
patients unlikely. However, it is important to understand the risks and
benefits of each technique, and herein we evaluate the outcomes of each.
Our approach to these patients has been to reserve arch replacement for
those who have arch aneurysmal disease, imminent risk of rupture, or
cerebral malperfusion, and perform a hemiarch replacement in all other
scenarios with arch involvement. Such approach is easily taught, safe,
and reproducible while focusing more on survival rather than long-term
freedom from reintervention.

The extent of surgical repair for type A aortic dissections involving
the aortic arch remains a controversial topic -- particularly with
regards to the distal extent of repair. The competing interests of
mitigating operative risk and avoiding late re-intervention are at the
forefront of this controversary. The conservative approach of simply
replacing the ascending aorta while avoiding intervention on the
dissected arch is the fastest and safest approach. However, leaving a
residual false lumen in the arch and descending aorta leads to aortic
dilation, which is associated with high re-intervention rates with
significant morbidity and mortality.\textsuperscript{1-3}

Conversely, total arch replacement at the time of acute dissection has
the advantage of decreasing the patency of the false lumen of the
residual aorta, which can induce reverse remodeling of the aorta leading
to decreased risk of aneurysmal dilation.\textsuperscript{4, 5} The
obvious benefit is a reduction in late re-interventions on the arch and
proximal descending aorta -- at the cost of increased operative
risk.\textsuperscript{4-6}

Unfortunately, decision-making in the extent of repair is not so
clear-cut. In addition to limited ascending replacement and total arch
replacement there are a multitude of variations in surgical approach
including composite root replacement, hemiarch replacement, classic
elephant trunk, open frozen elephant trunk, descending replacement, and
multiple novel endovascular techniques. This diversity in approach
combined with the broad spectrum of clinical variables, significant
diversity in clinical experience, and lack of any randomized data in the
literature has made a consensus on extent of surgical repair unlikely.

In the evaluation of each approach, it is important to first understand
the operative risk and risk of re-intervention after the different
strategies of type A dissection repair. At Washington University in St.
Louis, we evaluated the natural history of the residual aorta after
repair of acute type A aortic dissections over 10 years. In our series
of 168 patients, freedom from reoperation was 74\%, and over half of the
re-operations did not involve the aortic arch.\textsuperscript{3} After
multivariable regression, independent predictors of reoperation included
non-resected primary tear, absence of postoperative B-blocker therapy,
and elevated systolic blood pressure at late follow-up. Interestingly,
the extent of distal repair (ascending aortic replacement vs hemiarch)
did not affect aortic growth or need for late
reoperation.\textsuperscript{3}

In a follow-up series, we further explored these findings in 252
patients who underwent type A repair over the course of 25
years.\textsuperscript{7} Initial operative mortality was 16\% with a
5-year and 10-year survival of 78\%, and 59\%, respectively. Late
reoperation rate was 13\% and elevated systolic blood pressure at late
follow-up was found to be a powerful predictor of reoperation.
Specifically, freedom from reoperation for those with SBP \textless{}120
mm Hg was significantly higher at 92 \selectlanguage{ngerman}±5\% compared to with those with
SBP 120 mm Hg to 140 mm Hg (74\%±7\%) or \textgreater{}140 mm Hg
(49\%±14\%, P\textless{}.001).\textsuperscript{7} Further, reoperation
was markedly increased in patients not on B-blocker therapy. These
findings suggest that long-term, aggressive blood pressure control with
B-blockers is more important in avoiding late reoperation than the
extent of distal aortic resection.\textsuperscript{3, 6, 7}

In another robust series from Mt. Sinai\textsuperscript{2} including 179
patients who underwent type A aortic dissection repair, there was an
operative mortality of 13\% with a 5-year and 10-year survival of 78\%
and 66\%, respectively. The cumulative risk of reoperation on the distal
aorta at 10 years was 16\% -- one quarter of which were on the abdominal
aorta. The majority of patients in the series underwent hemiarch
replacement (54\%) or ascending replacement (36\%), and the most
important risk factors for reoperation were an aortic diameter exceeding
4 cm and a patent false lumen.\textsuperscript{2} Nonetheless, 84\% of
patients were free from aortic reintervention a decade after their
repair.

These data are similar to older data from France\textsuperscript{8} in
which 160 consecutive patients underwent Type A repair and 77\% were
free from reoperation on the arch or distal aorta at 10 years. In this
series, 15\% underwent arch replacement and distal extent of aortic
resection at initial operation did not significantly influence the risk
of distal reoperation. However, operative mortality was nearly double
more contemporary series at 32\% with 5-year and 10-year survival of
57\% and 52\%, respectively.\textsuperscript{8}

Lastly, data from Cleveland\textsuperscript{9} in which 208 patients
underwent type A repair with an operative mortality of 14\%, 85\% were
free from aortic re-intervention at 10 years. Over half of the
re-interventions were on the proximal aorta and extent of initial distal
resection did not influence reoperation or survival. However, 15\% of
patients underwent total arch replacement at the initial operation and
had significantly worse survival than those that underwent isolated
ascending replacement or hemiarch replacement.\textsuperscript{9}

Perhaps more important than the raw numbers of aortic reoperation is the
mortality of reoperation. In our group and others, the perioperative
mortality of reoperation on the distal aorta after type A repair appears
to be relatively low -- between 7-13\%.\textsuperscript{2, 3, 8} The
largest series evaluating the outcomes of distal aortic re-intervention
following type A dissection repair is from Roselli and
colleagues.\textsuperscript{1} They evaluated 305 type A aortic
dissection repair survivors who underwent 429 subsequent interventions
on the distal aorta over the course of 2 decades. Initial repairs
included ascending aorta replacement (74\%) and arch repair (25\%), and
the most common indication for re-intervention was distal aneurysmal
disease (95\%). Re-interventions included combinations of ascending
repair (69\%), Elephant trunk (48\%), total arch replacement (74\%), and
descending/thoracoabdominal replacement (37\%) with an overall
in-hospital mortality of 6.1\% and 10-year survival of 65\%. Not
surprisingly, infection, concomitant CABG, and combined arch and
descending repairs were associated with reduced in-hospital and late
survival.\textsuperscript{1}

Strategies to mitigate aneurysmal disease of the arch and descending
aorta following acute type A repair have led to various frozen elephant
trunk techniques. Pochettino and colleagues\textsuperscript{10} compared
42 hemiarch replacements to 36 hemiarch replacements with additional
open antegrade thoracic stent-grafting. Circulatory arrest times were
higher in the stented group, but operative mortality was equivalent
(14\%). At 15.9 months, open thoracoabdominal aneurysm repair was
required in 11\% of standard hemiarch patients compared with 0\% in
those with a frozen elephant trunk (p=0.08). However, one major
concerning trend was that transient paresis occurred in 9\% of the
stented group compared to 2\% of the non-stented
group.\textsuperscript{10} Further, 25\% of patients in the stented
group underwent endovascular reintervention to achieve false-lumen
obliteration.

Roselli and colleagues\textsuperscript{11} have developed a modified
technique of open frozen elephant trunk during acute type A repair that
includes a branched graft deployed in an antegrade fashion into the
descending aorta and left subclavian. Overall outcomes of this technique
have been impressive with an operative mortality of 4.2\% after 72 cases
and complete obliteration of the false lumen in 72\% of patients.
However, 4.2\% of patients suffered spinal cord injury and the
reintervention rate was 28\% at 5 years -- albeit all of reinterventions
were endovascular and there were no reintervention mortalities or late
paralysis.

Avoiding spinal cord ischemia is of critical importance when employing
the frozen elephant trunk technique and a recent meta-analysis by
Preventza and colleagues\textsuperscript{12} explored this relationship.
In their pooled analysis of 35 studies with 3154 patients who underwent
frozen elephant trunk, spinal cord ischemia was significantly higher
with stent length 15cm or greater or coverage beyond T8 than with stent
length of 10cm (11.6\% vs 2.5\%, P \textless{} .001). However, it is
important to mention that there is no distinction between permanent vs
transient spinal cord injury, and adjuncts such as cerebrospinal fluid
drainage and permissive hypertension can rescue patients who develop
spinal cord injury after distal aortic coverage.\textsuperscript{13, 14}

The most radical approach to acute type A dissections with arch
involvement is the total arch replacement with classic or frozen
elephant trunk. Most centers reserve total arch replacements for
patients with arch tears or an aneurysmal disease. However, if an arch
replacement is required, excellent results can be achieved in
experienced centers. Sun and colleagues\textsuperscript{4} from Beijing
performed a total arch replacement with frozen elephant trunk in 104
patients with type A dissection, reporting a low mortality rate of
8.6\%. Despite a low rate of radiographic follow-up with computed
tomography scans done in 65 patients at a mean of 4.6 years, no patient
underwent an intervention on the distal aorta, and the false lumen was
completely obliterated in 63. However, it is notable that there was a
2.9\% new postoperative paraplegia rate. In another impressive series of
total arch replacements from Japan, Omura and
colleagues\textsuperscript{15} performed 88 total arch replacements with
classic elephant trunk achieving a hospital mortality of 10.2\% and a
95\% freedom from intervention from reoperation at 5 years.

While results such as these achieve the goal of comparable mortality
with a lower reintervention rate compared to ascending and hemiarch
replacements, we must keep in mind that all data presented herein are
from aortic centers of excellence. It is difficult to imagine we can
expect such results in less experienced centers, particularly when the
most common hospital to perform type A dissection repair in the United
States does an average of 1 per year.\textsuperscript{16} As such, our
approach at Washington University in St. Louis has been to reserve total
arch replacement for cases in which the arch is aneurysmal, at imminent
risk of rupture, or there is cerebral malperfusion. For all other
scenarios, we tend to extend resection to a hemiarch when the tear
extends into the arch. Such technique is reproducible to our trainees
and can achieve the ultimate goal of maximizing survival rather than
long-term freedom from reintervention, which we mitigate with strict
long-term blood pressure control and beta blocker use.

\emph{References}

1. Roselli EE, Loor G, He J, Rafael AE, Rajeswaran J, Houghtaling PL,
Svensson LG, Blackstone EH and Lytle BW. Distal aortic interventions
after repair of ascending dissection: the argument for a more aggressive
approach. \emph{J Thorac Cardiovasc Surg} . 2015;149:S117-24 e3.

2. Halstead JC, Meier M, Etz C, Spielvogel D, Bodian C, Wurm M, Shahani
R and Griepp RB. The fate of the distal aorta after repair of acute type
A aortic dissection. \emph{J Thorac Cardiovasc Surg} . 2007;133:127-35.

3. Zierer A, Voeller RK, Hill KE, Kouchoukos NT, Damiano RJ, Jr. and
Moon MR. Aortic enlargement and late reoperation after repair of acute
type A aortic dissection. \emph{Ann Thorac Surg} . 2007;84:479-86;
discussion 486-7.

4. Ma WG, Zhang W, Wang LF, Zheng J, Ziganshin BA, Charilaou P, Pan XD,
Liu YM, Zhu JM, Chang Q, Rizzo JA, Elefteriades JA and Sun LZ. Type A
aortic dissection with arch entry tear: Surgical experience in 104
patients over a 12-year period. \emph{J Thorac Cardiovasc Surg} .
2016;151:1581-92.

5. Watanuki H, Ogino H, Minatoya K, Matsuda H, Sasaki H, Ando M and
Kitamura S. Is emergency total arch replacement with a modified elephant
trunk technique justified for acute type A aortic dissection? \emph{Ann
Thorac Surg} . 2007;84:1585-91.

6. Waterford SD, Gardner RL and Moon MR. Extent of Aortic Replacement in
Type A Dissection: Current Answers for an Endless Debate. \emph{Ann
Thorac Surg} . 2018;106:1246-1250.

7. Melby SJ, Zierer A, Damiano RJ, Jr. and Moon MR. Importance of blood
pressure control after repair of acute type a aortic dissection: 25-year
follow-up in 252 patients. \emph{J Clin Hypertens (Greenwich)} .
2013;15:63-8.

8. Kirsch M, Soustelle C, Houel R, Hillion ML and Loisance D. Risk
factor analysis for proximal and distal reoperations after surgery for
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9. Sabik JF, Lytle BW, Blackstone EH, McCarthy PM, Loop FD and Cosgrove
DM. Long-term effectiveness of operations for ascending aortic
dissections. \emph{J Thorac Cardiovasc Surg} . 2000;119:946-62.

10. Pochettino A, Brinkman WT, Moeller P, Szeto WY, Moser W, Cornelius
K, Bowen FW, Woo YJ and Bavaria JE. Antegrade thoracic stent grafting
during repair of acute DeBakey I dissection prevents development of
thoracoabdominal aortic aneurysms. \emph{Ann Thorac Surg} .
2009;88:482-9; discussion 489-90.

11. Roselli EE, Idrees JJ, Bakaeen FG, Tong MZ, Soltesz EG, Mick S,
Johnston DR, Eagleton MJ, Menon V and Svensson LG. Evolution of
Simplified Frozen Elephant Trunk Repair for Acute DeBakey Type I
Dissection: Midterm Outcomes. \emph{Ann Thorac Surg} . 2018;105:749-755.

12. Preventza O, Liao JL, Olive JK, Simpson K, Critsinelis AC, Price MD,
Galati M, Cornwell LD, Orozco-Sevilla V, Omer S, Jimenez E, LeMaire SA
and Coselli JS. Neurologic complications after the frozen elephant trunk
procedure: A meta-analysis of more than 3000 patients. \emph{J Thorac
Cardiovasc Surg} . 2020;160:20-33 e4.

13. Lou X and Chen EP. Commentary: The elephant in the room: Walking the
walk and talking the talk after a frozen elephant trunk
procedure.\emph{J Thorac Cardiovasc Surg} . 2020;160:34-35.

14. Lou X, Duwayri YM, Jordan WD, Jr., Chen EP, Veeraswamy RK and
Leshnower BG. The Safety and Efficacy of Extended TEVAR in Acute Type B
Aortic Dissection. \emph{Ann Thorac Surg} . 2020.

15. Omura A, Miyahara S, Yamanaka K, Sakamoto T, Matsumori M, Okada K
and Okita Y. Early and late outcomes of repaired acute DeBakey type I
aortic dissection after graft replacement. \emph{J Thorac Cardiovasc
Surg} . 2016;151:341-8.

16. Chikwe J, Cavallaro P, Itagaki S, Seigerman M, Diluozzo G and Adams
DH. National outcomes in acute aortic dissection: influence of surgeon
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. 2013;95:1563-9.

\selectlanguage{english}
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