[Changes in the true and false visceral segment lumen sizes following endovascular treatment of type B aortic...

The aim of the study was to assess technical success rates of endovascular procedures in acute and chronic type B aortic dissections and changes in the right (PL) and false (FL) lumen diameters in the visceral segment region during short-term and long-term follow up study periods.

From 2004 to 2009, the authors performed a prospective study, which included a total of 33 patients with acute and subacute (n = 16; 48.5%) or chronic (n = 17; 51.5%) type B dissections of the descending aorta, with dissections spreading as far as the visceral or infrarenal regions. The patients underwent successful implantations of stent grafts (SG) into the descending aorta. The study group included 7 female and 26 male subjects, at the time of the procedure, their mean age was 59 years, (34-70, the median of 56 y.o.a.). The mean follow up time was 39.3 months (8-68, the median of 41 months). During the study period, one of the patients exited due to another internal disorder, three subjects were converted to open replacements for progressing dilatation of the total diameter in the visceral or subrenal region. The true (PL) and false (FL) lumen diameters were measured at four levels: above the origin of truncus coeliacus (L 1), between the origin of truncus coeliacus and the origin of a. mesenterica superior (L 2), between the origin of a. mesenterica superior and the origin of aa. renales (L 3) and just distal to the origin of aa. renales (L 4). The measurements were performed 1 and 6 months after SG implantations and at the end of the study period.

The primary entry was successfully sealed in all the study subjects. Significant widening of the true lumen in the region sealed by the stentgraft was recorded in all the subjects, however, the false lumen did not completely disappear in 3 (9%) patients. The false lumen was completely filled with thrombus down to the celiac trunk level (L 1) within one month in 7 (21.2%) patients, within 6 months in 14 (42.4%) subjects and by the end of the study period in 19 (58.6%) patients. The true lumen continued to enlarge at all the measured levels. The most significant enlargement was recorded at L 1 during the first postoperative month (the mean change of 5.9 mm). Furthermore, narrowing of the originally patent false lumen was observed as well, with the most significant change at L1 level during the first postoperative month (the mean change of 6.5 mm). At six months and during the whole follow up study period, further increases in the right lumen diameter and in the total aortic diameter were recorded at all the measured levels. At the same time, the false lumen diameters at all the measured levels continued to narrow, if patent at all.

False lumen thrombosis along the extent of SG was recorded in 30 (91%) patients, SG filled the lumen completely and the false lumen disappeared. The true lumen expanded at all the measured visceral segment levels. The change was most significant during the first postimplantation month, and the true lumen expansions and the false lumen narrowing proceeded over the whole follow up study period, however, the progression was slower. The visceral segment true and false lumen changes will be monitored further.