Letter to the Editor Reply to the Letter to the Editor

In the article by Kuratani et al. [1], the investigators described excellent early and long-term results after extended selective visceral reconstruction and extended thoracic endovascular aortic repair (TEVAR). As outcome data on hybrid endovascular repair for thoraco-abdominal aortic aneurysms (TAAA) emerge, the renal implications of the procedure need to be scrutinized. Concern regarding the long-term effect on the renal function and the potential nephrotoxicity of intravenous contrast in the follow-up period must be considered [2]. In addition, manipulation of the aorta and visceral arteries may lead to the disruption of lipid-laden plaques and subsequent embolization into the renal vasculature [3,4]. Over the past 5 years, we performed the study to determine whether there is deterioration in renal function during follow-up in patients who have undergone TEVAR, as recommended by the Dutch Randomized Endovascular Aneurysm Management (DREAM) trial [5], and to explore the potential implication of lifelong surveillance of renal function with contrast-enhanced computed tomography. According to our results, mean serum-creatinine concentration increased and creatinine clearance decreased over longterm follow-up that is independent of preoperative renal disease and renal arterial occlusion in seven (12%) of 49 patients and is likely related to the repetitive administration of the contrast agent. Our results, and consecutively the conclusions, are similar to published data by Jacksonville, Pittsburgh, and New York group [2,3,4]. The findings reported by Kuratani et al. [1] included patients who had a lower frequency of some co-morbidities, including diabetes and hypertension, compared with the cohorts described in previous studies. Moreover, Asian people have lower body mass index and all findings reported by Kuratani et al. are of little help to clarify conflicting results about nephrotoxicity of intravenous contrast in the follow-up period from other observational studies and clinical trials [3,4]. Renal failure (RF) has been reported as one of the leading causes of postoperative death following conventional thoraco-abdominal aneurysm repair; also endovascular repair involved new potential risks specific to the procedure. According to our study results, the etiology of postoperative RF most likely is multifactorial, resulting from a combination of mechanical, atheroembolic, and contrastrelated contributors. In particular, the relationship between contrast type and volume and renal function after TEVAR has not been established. Contrast-induced renal insufficiency is reversible, yet in our patients, the noted creatinine rise was permanent in only one case of those patients who had deterioration of renal function: this suggests factors other than contrast exposure alone as contributory, suggesting atheroembolic sequelae. Unfortunately, obtained findings of the well-written article by Kuratani et al. [1] only analyzed data from a regional consortium and does not describe strategies, which could be adopted to minimize the likelihood of adverse renal effects associated with their hybrid procedure at all stages of evaluation and intervention. Only with demographic data, which are comparable between European and Asian population, and treatment recommendations for prevention of RF, we could attempt to push the limits of such or similar hybrid procedures in the treatment for TAAA.