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

BACKGROUND: 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). METHODS: 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). RESULTS: 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). CONCLUSIONS: 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.