Assessment of renal trajectory revealed that all groups experienced a decrease in post-operative renal function on the first and second days after nephrectomy, as was expected. However, only patients in the IVC TT group recovered. At greater than 90 days, the absolute changes in estimated glomerular filtration rate (eGFR) among the IVC TT, open radical nephrectomy, and laparoscopic nephrectomy groups were –10, –25, and –25, respectively. eGFR declined by approximately 21% in the IVC TT group compared with approximately 38% in the other 2 groups.
The study authors asserted that these findings not only provide clinical proof of the reversibility of renal dysfunction, but also indicate that renal injury is hemodynamic rather than structural. This, in turn, could explain how patients with RCC and IVC thrombosis recover renal function post-operatively despite having a worse baseline estimated glomerular filtration rate (eGFR).
“This [phenomenon] cannot be explained by nephron loss,” Lorraine Scanlon, MD, of Trinity College Dublin in Ireland, stated during her oral presentation. “Congestive nephropathy offers a unifying explanation, reframing chronic kidney disease in IVC thrombosis and supporting timely thrombectomy to relieve venous pressure.”
How was this study designed?
Scanlon and her coauthors performed a comparative cohort study which included data from 2002 to 2023. The study comprised 3 groups: patients who underwent radical nephrectomy plus IVC TT (n = 23), those who underwent open radical nephrectomy alone (n = 35), and those who underwent laparoscopic radical nephrectomy alone (n = 23). The study’s primary objective was to assess the change in eGFR after more than 90 days.
At baseline, patients who underwent IVC TT had larger tumors, higher-grade kidney disease according to the American Society of Anesthesiologists physical status classification system, and poor baseline eGFR; however, this patient population also displayed superior renal preservation compared with patients who did not undergo this procedure.
How might these findings shift current understanding of acute kidney injury in the context of RCC with IVC thrombosis?
Traditional frameworks of acute kidney injury involve 3 main phases:1,2
- The pre-renal phase: characterized by decreased blood flow, or perfusion, to the kidneys
- The intrinsic phase: involving direct damage to the nephron
- The post-renal phase: caused by an obstruction in the urinary tract that prevents the outflow of urine from the kidneys. The resulting buildup of pressure and waste products leads to hydronephrosis.
Although this framework has significant utility, these mechanisms do not explain the pattern of renal function recovery observed among patients with IVC thrombosis.1
“These patients have normal arterial inflow, no parenchymal injury, and no ureteric obstruction, so the classic triad doesn't explain the renal impairment,” Scanlon explained. “This pattern [of renal recovery] doesn't behave like chronic kidney disease, which we [understand to be] structural [and irreversible]; it suggests a gap in how we conceptualize renal dysfunction in these patients.”
Accordingly, Scanlon and colleagues proposed an alternative driver of renal dysfunction present in this patient population: renal venous outflow obstruction. The resulting investigation provided clinical proof-of-concept for this proposed mechanism.
Prior to surgery, investigators found that venous obstruction was increasing pressure on the kidneys and blocking the outflow of blood, thereby decreasing filtration in the nephrons. After thrombectomy, however, the normal outflow of blood was restored and the filtration gradient normalized, leading to a recovery of nephron function.
“Ultimately, [these findings] introduce a fourth mechanism of renal dysfunction, and it may change how we [manage] patients [with RCC and IVC thrombosis] and design perioperative studies.”
References
- Scanlon L. Relief of venous congestion as a modifiable cause of renal dysfunction in RCC with IVC tumor thrombus: a comparative cohort study. Presented at: 26th Annual Meeting of the Society of Urologic Oncology. December 2-5, 2025; Phoenix, Arizona.
- Goyal A, Daneshpajouhnejad P, Hashmi MF, et al. Acute kidney injury. StatPearls. Updated November 25, 2023. Accessed December 4, 2025. https://www.ncbi.nlm.nih.gov/books/NBK441896/
