Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2020 Jul 15;6(8):e581.
doi: 10.1097/TXD.0000000000001034. eCollection 2020 Aug.

Postoperative Ultrasound in Kidney Transplant Recipients: Association Between Intrarenal Resistance Index and Cardiovascular Events

Anouk van de Kuit  1 , Stan Benjamens  1   2 , Camilo G Sotomayor  3 , Elsaline Rijkse  4 , Stefan P Berger  3 , Cyril Moers  1 , Stephan J L Bakker  3 , Robert C Minnee  4 , Derya Yakar  5 , Robert A Pol  1
Affiliations

Postoperative Ultrasound in Kidney Transplant Recipients: Association Between Intrarenal Resistance Index and Cardiovascular Events

Anouk van de Kuit et al. Transplant Direct. .

Abstract

Doppler ultrasound, including intrarenal resistance index (RI) measurement, is a widely used modality to assess kidney transplantation (KTx) vascularization. The aim of this study is to gain insight in the associations between early postoperative RI measurements and cardiovascular events (CVEs), all-cause mortality, and death-censored graft survival.

Methods: From 2015 to 2017, a prospective cohort study was conducted in patients in which RI measurement was performed immediately after KTx. The RI was calculated as (peak systolic velocity-end-diastolic velocity)/peak systolic velocity. End points were CVEs, all-cause mortality, and graft failure. Kaplan-Meier analyses (logrank test) were used for differences in end points. Univariate and multivariate associations were investigated by means of Cox regression analyses.

Results: RI cutoff of 0.70 was used. We included 339 recipients, of which 271 (80%) had an RI ≤ 0.70 and 68 (20%) had an RI > 0.70. CVEs were observed in 27 (8%) patients, 27 (8%) patients died, and 17 (5%) patients had graft failure during a median follow-up of 37 months (interquartile range, 33-43). Kaplan-Meier analyses and univariate Cox regression indicated a significant association with overall CVE-free survival (hazard ratios [HR], 2.79; P = 0.011; logrank test, P = 0.008) and all-cause mortality (HR, 2.59; P = 0.017; logrank test, P = 0.013) for patients with an RI above and below 0.70. An independent association was shown between an RI > 0.70 and CVE-free survival (HR, 2.48; P = 0.042) when deceased donation was not included in the model.

Conclusions: In the early postoperative period, a high RI showed to be associated with CVEs after adjustment for cardiovascular risk factors, whereas no independent association was found with overall survival and graft failure. For the interpretation of RI measurements after KTx surgery, patients' cardiovascular state should be taken into consideration.

PubMed Disclaimer

Conflict of interest statement

The authors declare no funding or conflicts of interest.

Figures

FIGURE 1.
FIGURE 1.
Kaplan-Meier curves of 1-y CVE-free survival, 1-y patient survival, and 1-y death-censored graft survival. CVEs, cardiovascular events; RI, resistance index.
FIGURE 2.
FIGURE 2.
Kaplan-Meier curves of overall CVE-free survival, overall patient survival, and overall death-censored graft survival. CVEs, cardiovascular events; RI, resistance index.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

References

    1. Kolofousi C, Stefanidis K, Cokkinos DD, et al. Ultrasonographic features of kidney transplants and their complications: an imaging review. ISRN Radiol. 2013; 2013:480862. - PMC - PubMed
    1. Benjamens S, Glaudemans AWJM, Berger SP, et al. Have we forgotten imaging prior to and after kidney transplantation? Eur Radiol. 2018; 28:3263–3267 - PubMed
    1. Kidney Disease: Improving Global Outcomes (KDIGO) Transplant Work Group. Special issue: KDIGO clinical practice guideline for the care of kidney transplant recipients. Am J Transplant. 2009; 9:S1–S155 - PubMed
    1. Radermacher J, Mengel M, Ellis S, et al. The renal arterial resistance index and renal allograft survival. N Engl J Med. 2003; 349:115–124 - PubMed
    1. Naesens M, Heylen L, Lerut E, et al. Intrarenal resistive index after renal transplantation. N Engl J Med. 2013; 369:1797–1806 - PubMed