**5. Types of endoprostheses in use**

180 Aneurysm

**Figure 6.** Classification of AAA (modified after [40])

 **A B C D E F**

Straight Tapered Reversed tapered Angulated <30° Bulge

**Figure 7.** Morphology of the aortic neck (modified after [40])

**Figure 8.** Preoperative measurements (EUROSTAR)

The grafts are classified in different manners. From the anatomic point of view, they can be: bifurcated (Ao bi-iliac), Ao – uni-iliac and tube (for Ao – Aortic – these were the most used, but now they are out of the market). They can be modular (most of them) or unibody (Powerlink).

**Figure 9** shows the images of some endoprosthesis in use today: modular (a,b,c) and unibody (d).

*a) Anaconda b) Talent c) Zenith d) Powerlink* 

#### **Figure 9.** Most used endoprosthesis

The modular devices have at least two component grafts. The main body deployed on the neck of the aneurysm *("hanging from the Aorta")* and the two legs that arrives on the common iliac arteries. The unibody prostheses build up the endoluminal channel from the bottom to the top, sitting on the aortic bifurcation (concept of anatomical fixation) [55]. This prevents distal migration of the endoprostheses.


The characteristics of the most used endografts [56, 57] are shown in the **table 2:** 

**Table 2.** The characteristics of the most used endografts [56, 57]

The characteristics of an ideal stent graft are:


The new results of the endovascular management of AAA (by type of endograft) are shown in **table 3** (retrospective or prospective studies) published in 2010 [58-63].

EVAR is not a procedure without complications[64-66]. One of the most redoubtable are the *endoleak* [67]. They are defined as persistence of the blood flow outside the lumen of the endograft, but within the aneurismal sac [68]. An endoleak may perfuse the aneurysm sac leading to aneurysm expansion and may be rupture. It represents the inability to obtain or maintain secure seal between the aortic wall and the graft [1]. The incidence of endoleaks is in range of 14%. They are classified in four types (from I to IV) [see the **table 4** [1] modified].

The technique of introduction and deployment of the endograft is shown in **figure 10**. The access sites are the two femoral arteries. The anaesthesia required is general anaesthesia or loco-regional (peridural) [69].


**Table 3.**

182 Aneurysm

**Zenith**

**Talent**

**Excluder**

**Anaconda**

**Powerlink**

**E-Vita** 

 Low overall cost, Stent-graft size ranging,

 Radial force stability, Customization

loco-regional (peridural) [69].

**Device Material Confi-**

(Cook) Polyester Modular Self-

(Medtronic) Polyester Modular Self-

(Gore) ePTFE Modular Self-

(Terumo) Twilleave Modular Self-

**(**Jotec**)** Polyester Modular Self-

The characteristics of an ideal stent graft are:

Good biocompatibility and sealing capacity,

piece

**Table 2.** The characteristics of the most used endografts [56, 57]

Long durability (metallic ultrastructure + graft material),

Delivery device flexibility, lowest delivery device size,

in **table 3** (retrospective or prospective studies) published in 2010 [58-63].

(Endologix) ePTFE One-

The characteristics of the most used endografts [56, 57] are shown in the **table 2:** 

**Endograft characteristics**

Compression-

Compression-

Compressionfit and anchors

Compression-

Compression-

Compression-

**Aortic graft diam.** 

fit and barbs 22-36 8-24 Yes

fit 24-34 8-24 Yes

23/26/28.5 12-

fit 25/28 16 Optional

fit 24/34 14-26 yes

fit and hooks 19.5-34 9-18 No

**Iliac graft diam.** 

14.5 No

**Suprarenal stent** 

**guration Deployment Fixation** 

expanding

expanding

expanding

expanding

Selfexpanding

expanding

The new results of the endovascular management of AAA (by type of endograft) are shown

EVAR is not a procedure without complications[64-66]. One of the most redoubtable are the *endoleak* [67]. They are defined as persistence of the blood flow outside the lumen of the endograft, but within the aneurismal sac [68]. An endoleak may perfuse the aneurysm sac leading to aneurysm expansion and may be rupture. It represents the inability to obtain or maintain secure seal between the aortic wall and the graft [1]. The incidence of endoleaks is in range of 14%. They are classified in four types (from I to IV) [see the **table 4** [1] modified]. The technique of introduction and deployment of the endograft is shown in **figure 10**. The access sites are the two femoral arteries. The anaesthesia required is general anaesthesia or


**Table 4.** Classification of Endoleaks [1]

Both types I and III are significant risk factors for late aneurysm rupture and should be treated. Types II are considered benign and type IV usually resolves spontaneously during the post procedure period.

With this procedure, we can reduce blood lost (using also devices like the cell-saver) and consequent transfusion requirement, ITU and hospital stay. More patients can be treated where comorbidity previously excluded them. The follow-up is done by using CT scan exams at 1, 3, 6 and 12 months after the procedure. There are changes in the aneurysm volume after endovascular repair in terms of shrinking [61,70,71].

**Figure 10.** Schema of modular endograft deployment
