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CARDIOVASCULAR JOURNAL OF AFRICA • Volume 27, No 3, May/June 2016

AFRICA

145

strokes in two. All five patients with neurological complications

survived and were released from hospital. One stroke patient died

of pneumonia with sepsis within three years. Twenty-six (51%)

patients required transfusions of more than 500 ml packed red

blood cells after surgery, and four (8%) underwent re-sternotomy

for haemostasis. Furthermore, 12 (23%) had pneumonia, five

(9%) had ARDS, and 22 (43%) developed acute renal failure.

The subclavian group showed a significantly lower incidence of

mediastinitis (

p

=

0.01), neurological dysfunction (

p

<

0.001), acute

renal failure (

p

=

0.03), and mortality (

p

=

0.04) (Table 2).

In the 24-hour postoperative biochemistry data (Table 2),

we found metabolic acidosis and hyperamylasaemia to be

significantly higher (

p

<

0.05) in the femoral artery group. In

addition, higher troponin I and C-reactive protein and lower

albumin levels were also noted in the femoral artery group (

p

<

0.05). The survivors in the subclavian artery group had a shorter

mean ventilator-dependent duration (6.0

±

4.8 vs 6.4

±

3.5 days)

as well as ICU (8.9

±

5.8 vs 13.3

±

9.1 days) and hospital stay (18.8

±

9.8 vs 34.1

±

22.6 days) than those in the femoral artery group.

The compared Kaplan–Meier survival curve for the two

groups is shown in Fig. 1. All 40 survivors were followed up

for three years with annual CT angiography. Two patients died

within one year of surgery, one of sudden death and the other

of a cerebral vascular accident. Two more patients died within

the next two years, one of pneumonia with severe sepsis and the

other following recurrent dissection of the aortic root.

According to the outcomes of the annual CT angiography

(Fig. 2), three root re-dissections were found; two underwent

re-do Bentall’s operation and the other died of sudden death

without re-operation. Four arch dissections without branch

involvement were found and all four adopted conservative

treatment. Two arch aneurysms were found and one underwent

re-do arch reconstruction due to impending rupture. Three

dissecting aneurysms of the descending aorta were found and all

three underwent thoracic endovascular aortic repair (TEVAR).

The other 28 were diagnosed with type B dissection and adopted

conservative treatment. Overall survival was 75% at one year and

70% at three years.

Results of univariate and multivariate analysis are shown in

Table 3. Logistic regression analysis revealed independent risk

factors for hospital death as pre-operative respiratory failure,

peri-operative CPB

>

200 min, postoperative severe acidosis (pH

<

7.2), and troponin I

>

2.0 ng/ml.

Discussion

There is a trend towards cannulation of the axillary artery for

extracorporeal circulation in patients with AADA,

1-4

but the

debate is ongoing and several possible reasons could explain this

deficiency, including the following: (1) the urgency of AADA

does not allow for complicated surgical techniques but instead

requires a simple, rapid and safe approach to achieve rapid

extracorporeal circulation; (2) the different individual situations

demand an individual approach, and it is difficult to relate

outcome to the cannulation site; (3) the number of procedures

performed at each centre is rather small, especially in Asia, while

a multicentre approach is not practicable owing to the different

strategies practiced at different centres; and (4) most important

of all, the severity of the AADA hinges on the location of the

torn intima and the extent of the dissection, which also demands

different types of procedures. In this study, we enrolled only

cases involving ascending aorta reconstruction to avoid major

Table 2. Post-operative general data and short-term outcomes

Postoperative data

Total

Femoral

group

(

n

=

26)

Subclavian

group

(

n

=

25)

p

-value

pH

7.26

±

0.15 7.35

±

0.05 0.01

PaO

2

(mmHg)

115

±

92 136

±

75 0.37

HCO

3

-

(mEq/dl)

20.5

±

4.5 22.6

±

3.1 0.06

Amylase (U/l)

316

±

482 101

±

159 0.04

Lipase (U/l)

98

±

158 41

±

57 0.09

GOT (U/l)

391

±

1078 70

±

113 0.14

GPT (U/l)

286

±

890 33

±

29 0.16

Troponin I (ng/ml)

7.5

±

11.9 0.1

±

0.3 0.003

CRP (mg/dl)

10.9

±

8.0 5.4

±

3.5 0.003

Albumin (g/dl)

2.9

±

0.4 3.3

±

0.4 0.001

Short-term outcomes

Total number,

n

(%)

51

26 (100)

25 (100)

Transfusion

>

500 ml,

n

(%)

26 (51)

15 (57)

11 (44)

0.32

Resternotomy,

n

(%)

4 (8)

2 (7)

2 (8)

1.00

Mediastinitis,

n

(%)

2 (4)

2 (7)

0 (0)

0.01

Neurological dysfunction,

n

(%)

5 (9)

5 (19)

0 (0)

0.001

Pneumonia,

n

(%)

12 (23)

8 (27)

4 (16)

0.36

ARDS,

n

(%)

5 (9)

3 (11)

2 (8)

0.67

Acute renal failure,

n

(%)

22 (43)

15 (57)

7 (28)

0.03

Mortality,

n

(%)

11 (21)

9 (34)

2 (8)

0.04

The biochemical tests were recorded 24 hours after surgery. GOT, glutamate

oxaloacetate transaminase; GPT, glutamate pyruvate transaminase; CRP,

C-reactive protein; ARDS, acute respiratory distress syndrome.

0 50 100 150 200 250 300 350

Days

Cum survival

1.0

0.8

0.6

0.4

0.2

0.0

Subclavian canulation

Femoral canulation

+

+

Fig. 1.

Kaplan–Meier survival curve in relation to the two

groups.

40 survivors

3 root re-dissection

4 arch dissection

2 arch aneurysm

3 dissecting

aneurysm of

descending aortic

28 type B

dissection

2 re-do Bentall’s

procedure

Conservative

treatment

1 re-do arch

reconstruction

3 TEVAR

Conservative

treatment

Fig. 2.

Outcomes of the annual CT angiography and follow-up

intervention.