Impact of true or false lumen renal perfusion after type B aortic dissection on renal volume

The aim of this study was to analyse the influence of true, false, and combined lumen perfusion of renal arteries on mid- and long-term kidney volume in patients with type B aortic dissection (TBAD).

Retrospective analysis of patients diagnosed with a TBAD between 2008 and 2015 in a single high-volume European center. The origin of the renal arteries was evaluated on a dedicated 3D workstation (TeraRecon Inc., San Mateo, CA, USA) and coded as either arising from the true lumen (TL), false lumen (FL) or from a combination of both (CL). Additional evaluated anatomical parameters were renal volume, length, width, and depth of the kidneys. Measurements were recorded at the time of diagnosis (T0) and at 1-month (T1), 6-months (T2), 18-months (T3) and 36-month of follow-up time (T4).

A total of 131 renal arteries and kidneys were evaluated in 69 patients. Mean age was 64±13 years and 77% were male. The absolute number and percentage of assessed renal arteries/kidneys was 131 (100%) at T0, 89 (68%) at T1, 73 (56%) at T2, 57 (44%) at T3 and 43 (44%) at T4. At the time of diagnosis, 71.6% renal arteries originated from the TL, 19.1% from the FL and 9.2% from a CL. TEVAR was performed in 92.7% patients and nine patients had additional renal artery stenting. At T0 the mean renal volume was 212.1±70.9cm³, 178±61.2 in women versus 222.2±70.6 in men (P=0.002). Forty-three percent of the patients had a renal volume reduction ≥15% from T0 to their last available CTA. Mixed model analysis showed a significant overall renal volume reduction of 13.7cm³ from T0 to T4 (P<0.05). No significant differences in renal-volume reduction were observed depending on origin of the renal artery, though an estimated reduction of renal volume from T0 to T4 of 40.8 cm³ was seen when the kidneys were perfused by a CL, while TL perfusion only caused a reduction of 15.6 cm³ and no relevant volume change over time was observed when the renal artery originated from FL. Alongside a renal volume reduction, mixed model analysis also showed a significant serum-creatinine increase, from 0.8618mg/at T0 to 1.38±0.56 mg/dL at T4 (P<0.001), as well as a significant glomerular filtration rate reduction over time, from > 60mL/min at T0 to 49±13 mL/min at T4 (P<0.001). A negative correlation was observed between creatinine values and renal volume change, while a positive correlation was observed between GFR and renal volume change (P<0.001).

There is a significant mid-term renal-volume reduction in patients with TBAD, independent of the origin of the renal arteries. Albeit not statistically significant, combined renal artery perfusion may lead to a greater volume reduction, potentially secondary to a relevant dynamic compression by the dissection membrane. Further multicentre studies are warranted to determine the effect on long-term renal function and on possible preventive strategies.