Pathologies and treatment

Aneurysmal disease

Arterial aneurysms are defined as: Dilation or enlargement of the aorta to at least twice its normal size. While they can potentially affect all the arteries in an organism, they are mainly found at the level of the subrenal abdominal artery at the level of the knee (popliteal artery). They can be complicated by cataclysmic internal hemorrhage through rupture or occlusion of small arteries by embolism of the blood clot in the aneurysm. Risk of complications is correlated with aneurysm diameter, which is why treatment of aneurysms is indicated from a certain diameter upwards, usually 5 cm for the abdominal, or if the aneurysms are responsible for pain.

Aneurysm of the abdominal aorta viewed by scanner (*) indicates that the aneurysm contains a central white part corresponding to the interior of the artery and a dark part corresponding to the clot.
Aneurysm of the abdominal aorta viewed by scanner (*) indicates that the aneurysm contains a central white part corresponding to the interior of the artery and a dark part corresponding to the clot.
Aneurysm complicated by rupture viewed by scanner (*) indicates the aneurysm; (+) indicates a hematoma around the aneurysm, which corresponds to rupture of the artery
Aneurysm complicated by rupture viewed by scanner (*) indicates the aneurysm; (+) indicates a hematoma around the aneurysm, which corresponds to rupture of the artery.

The classical repair technique  necessitates opening of the abdomen and artificial clamping to remove the aneurysm from blood circulation. The aneurysm is opened, the clot is withdrawn, and then a vascular prosthesis is installed. Known as an open repair technique, this surgery was performed for the first time in the world in 1953 by  Pr Dubost (Hôpital Broussais, Paris). It can now be affirmed that this technique is of durable value. It necessitates a ten-day hospital stay including a few days of monitoring in intensive care. It is the first-line treatment for patients presenting with few surgical risks. Its mortality and complication rate range from 1 to 3% depending on the experience of the operating team. The vascular surgery department of the Poitiers CHU is highly trained and performs about 30 operations of this type per year.

Endovascular treatment is the other, more recent method. It was initiated by  Parodi and Volodos in the 1990s. It consists in removing the aneurysm from blood circulation by installing a prosthesis equipped with metallic stents; an aortic endoprosthesis. It is tucked into a catheter and introduced into the artery with access through the femoral artery at the fold of the groin. Once the position of the endoprosthesis has been radiologically verified during the operation, it is released. This technique is associated with particularly low mortality (1%). It renders the intervention less extensive and was initially reserved for fragile patients who would have had difficulty enduring the classical technique. However, it presents a number of drawbacks. Its preparation necessitates a number of anatomical constraints: There must exist sufficient distance between the renal arteries and the border of the aneurysm.  Following the operation, lifetime monitoring by scanner / echo doppler is required; in spite of the presence of the endoprosthesis, the aneurysm can begin to grow again through transgraft microleaks.

endoprotheses-aortiques endoprotheses-aortiques1
Example of two aortic endoprostheses regularly implanted at the Poitiers CHU.
The stent-equipped prosthesis takes on the aspect of a pair of pants.
The stent-equipped prosthesis takes on the aspect of a pair of pants.
Endoprosthesis control by scanner. Two leg extensions (*) enable blood to flow between the two legs. The surrounding aneurysm is filled with clots and is shaded dark (°).
Endoprosthesis control by scanner. Two leg extensions (*) enable blood to flow between the two legs. The surrounding aneurysm is filled with clots and is shaded dark (°).

At this time, there exist alternative techniques for treatment of more complex aneurysms; using these methods, it has become possible to reach the start of the arteries and continue through the digestive tract and the kidneys. Installation of an endoprosthesis necessitates preliminary selective catheterization of these arteries in order to “protect” them by means of small stents. They correspond to the windowed and branched aortic endoprostheses or to “chimney-graft” techniques. The vascular surgery department of the Poitiers CHU is one of the rare centers able to apply all of these endovascular techniques in the Poitou-Charentes region.

The stent-equipped prosthesis once again takes on the aspect of a pair of pants.
The stent-equipped prosthesis once again takes on the aspect of a pair of pants.
Illustration showing a windowed endoprosthesis rising above the 2 renal arteries. The holes present in the endoprosthesis permit installation of stents in the renal arteries, thereby protecting them from blood flow.
Illustration showing a windowed endoprosthesis rising above the 2 renal arteries. The holes present in the endoprosthesis permit installation of stents in the renal arteries, thereby protecting them from blood flow.
Postoperative scanner control of an endoprosthesis of the descending thoracic aorta.
Postoperative scanner control of an endoprosthesis of the descending thoracic aorta.

Treatment of aortic thoracic aneurysms has been strongly impacted by the arrival of endovascular techniques, which have markedly diminished the cumbersomeness of conventional surgery. No extra-corporeal  circulation is necessitated. The vascular surgery department performs from 5 to 10 procedures a year at the level of the thoracic aorta.[:]