Total arch replacement with separated graft technique and selective antegrade cerebral perfusion Flashcards Preview

CVPR 312 Cardiac Pathophysiology > Total arch replacement with separated graft technique and selective antegrade cerebral perfusion > Flashcards

Flashcards in Total arch replacement with separated graft technique and selective antegrade cerebral perfusion Deck (23):
1

It is essential to select the optimum method of cerebral protection and operative technique for arch repair to improve the surgical outcome of arch aneurysm or dissection. Selective antegrade cerebral perfusion (SACP) is our current method of choice if ?

required cerebral protection time exceeds 30 minutes.

2

What is a safe and effective for brain protection in a majority of patients

Moderate hypothermic two-arch vessel perfusion (innominate artery or right axillary artery and left common carotid artery)

3

What is the preferred surgical procedure used for arch aneurysm or dissection?

The separated graft technique using 4-branched graft

4

SACP allows us to perform meticulous arch repair and facilitates the time-consuming total arch replacement for complex aortic arch pathology and results in an acceptable mortality which is?

(less than 4%) and morbidity (stroke 3%).

5

The two major causes of postoperative neurological dysfunction are

cerebral ischemic injury due to interruption of the cerebral circulation and cerebral embolism due to disloged atherosclerotic debris during the surgical procedure.

6

Three major techniques of cerebral protection

1.) (DHCA) with (RCP)
2.) (DHCA) without (RCP)
3.) (SACP) with moderate hypothermia (Preferred Method)

7

We routinely perform preoperative cerebral 4-vessel (bilateral internal carotid and vertebral arteries) angiography and cerebral computed tomographic scanning or magnetic resonance imaging for what purpose ?

Rule out cerebrovascular diseases, and to select the site of cerebral perfusion.

8

We monitor cerebral perfusion pressure through

-the right radial arterial pressure and bilateral catheter tip pressure and perfusion flow rate.
-EEG or BIS to monitor the electrical activity of brain.

9

What is two-channel near-infrared spectroscopy (NIRS) used for?

to estimate regional cerebral oxygenation

10

use internal jugular venous oxygen saturation to monitor

cerebral oxygen saturation

11

use transcranial Doppler sonography to measure

the flow velocity in the middle cerebral artery.

12

Before the ascending aorta is cannulated, epiaortic echo scanning and transesophageal echocardiography are routinely performed to

assess whether atherosclerotic plaques are present in the ascending aorta and the aortic arch.

13

If the ascending aorta is found to be inappropriate for arterial cannulation by epiaortic echo scanning because of the presence of atherosclerotic debris, the preferred alternative site for arterial cannulation is the?

right axillary artery.

14

SACP is commenced at a rate of

10 mL/kg/min

15

The left subclavian artery is kept cross-clamped during SACP except in the following cases where additional left subclavian artery perfusion is instituted:

(I) occlusion of the right vertebral artery; (II) lack of adequate intracranial communication and (III) dominant left vertebral artery.

16

The radial artery pressure as well as bilateral catheter tip pressures are adjusted to maintain a mean perfusion pressure of around

40 mmHg

17

The radial artery pressure as well as bilateral catheter tip pressures are adjusted to maintain a mean perfusion pressure of around 40 mmHg. During CPB, arterial blood pH is managed utilizing

alpha-stat strategy.

18

More recently, unilateral cerebral perfusion through the right axillary artery instead of bilateral cerebral perfusion is used in selected patients undergoing

hemiarch replacement for acute type A dissection

19

SACP can extend the safe duration of cerebral protection up to

90 minutes, and facilitates complex aortic arch repair

20

2 hypothermia-related complications

pulmonary insufficiency and coagulopathy

21

The suggested drawback of SACP includes the risk of cerebral embolism or malperfusion while cannulating the arch vessels. In order to avoid cerebral embolization of the dislodged atherosclerotic debris during arch vessel cannulation, special care should be taken as follows:

1.) arch vessels are transected about 1 cm distal to their origin where they are free from atherosclerotic debris.
2.) avoid cerebral malperfusion in acute aortic dissection, the true lumen should be distinguished from the false lumen

22

Since we have adopted SACP and the separated graft technique in patients with acute type A dissection, we have become more aggressive at performing extended aortic arch replacement in selected patients. Our current 6 indications for total arch replacement in these patients are:

(I) acute aortic arch dissection with a tear in the aortic arch; (II) acute type A aortic dissection with a tear in the proximal descending aorta (retrograde type A dissection); (III) rupture or massive false lumen of the aortic arch;
(IV) compromise of arch vessels;
(V) coexistent aortic arch aneurysm; and
(VI) young Marfan patient without serious dissection-related complications.

23

It is critical to avoid embolic events during the operation through a number of important steps:

(I) epiaortic echo scanning is routinely performed to select the site of ascending aortic cannulation;
(II) the right axillary artery is used as an alternative site of cannulation if the ascending aorta is not suitable;
(III) the arch vessels are transected where they are free from atherosclerosis and are cannulated under direct vision through the transected vessel;
(IV) antegrade systemic perfusion through the side branch of the arch graft is commenced after the distal anastomosis is completed to prevent retrograde embolization;
(V) the ascending or descending aorta containing clot or atheroma is completely resected and is replaced with the branched arch graft.