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Home > Press Center > Press Releases from 2005 Annual Meeting > Endografts are promising treatment for acute and chronic aortic dissections

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Jill Goodwin
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A preliminary study suggests that endografts may offer a promising means for treating acute and chronic descending thoracic aortic dissections. Tae K. Song, MD headed the study team at Harbor UCLA Medical Center, Torrance, Calif., and presented the results at the annual meeting of the Society for Vascular Surgery in Chicago.

Aortic dissection is a tear or separation of the tissue layers within the aortic wall, which allows blood to surge into the wall. This column of blood forms a false lumen or channel within the aorta, which usually extends distally to the lower parts of the body. This often results in compromised blood flow in any artery coming off the aorta, and the aortic valve may become dysfunctional. Dissection is considered acute if it is less than two weeks old. It is associated with high morbidity and mortality rates. Dissection is called chronic in  patients who have had the condition longer than two weeks. They usually have a better prognosis.
 
The study sought to evaluate the impact of thoracic endografts in excluding acute and chronic descending thoracic aortic dissections and to compare postoperative outcomes of endograft placement for both acute and chronic interventions. All patients in the study were chosen on the basis of having a Stanford Type B dissection (distal to the left subclavian artery) as determined by intravascular ultrasound. All 42 patients (25 acute, 17 chronic) were enrolled in FDA-approved protocols from August 1999 to March 2005. CT reconstructions were used to make 3D imaging and quantitative volume assessments of false lumen regressions.

Complete thrombosis of the false lumen in the segment covered by the endograft occurred in 25 of the 41 patients within one month (61 percent) and in 15 of 17 patients within one year (88 percent). Volume regression of the false lumen was 66.4 percent (acute) and 91.9 percent (chronic) at 6 months, but only the chronic dissections proceeded to zero. Acute dissections without reintervention were found to have increases in true lumen volume of 32.1 percent and 41.7 percent at 6 and 12 months, compared to 15.2 percent and 37.0 percent for chronic dissections. Acute dissections requiring reintervention demonstrated minimal changes in true lumen volume from 6 to 12 months (4.8 percent to 3.9 percent). A lack of true lumen volume increase and increasing false lumen volumes are suggestive of continued false lumen pressurization and the need for secondary reintervention. Thirteen patients (31 percent) required 18 secondary interventions for proximal endoleaks (6), junctional leaks (3), continued perfusion of the false lumen from distal re-entry sites (3), and surgical conversion (4) for retrograde dissection. There was a 6.7 percent procedural mortality and no paraplegia.  The left subclavian artery was occluded in 11 patients (26 percent) with no complaints of arm ischemia, but there was a possible association with posterior circulation strokes (3/11).

In his summary, Dr. Song concluded that the study’s preliminary experience with endografts for acute and chronic dissections has shown promising results with a dramatically reduced risk of paraplegia and lower mortality compared to open surgical treatment and/or results from medical treatment alone. The high rate of regression of dissections and low rate of complications with endograft treatment of both acute and chronic dissections warrants further investigation, Song said.