Intrarenale Dopplerflußanalysen bei nierentransplantierten Patienten 
mit stabiler Transplantatfunktion

Ik, Restrepo-Schäfer; Wb, Schwerk; Tf, Müller; Prinz, Heino; Görg, Christian; Arnold, Richard

doi:10.1055/s-1999-14242

Cited by 22 publications

(3 citation statements)

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“…A next step would be to compare intrarenal RI in patients with renal artery stenosis and the internal carotid RI to harden this suggestion. We could not show a positive correlation between renal function and RI as described in former studies (14,38). Only patients with a low FRS had a significant correlation with the transplant RI in our cohort, while Heine et al found that renal transplant recipients with a high cardiovascular risk had increased RIs.…”

Section: Discussioncontrasting

confidence: 66%

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation

Köger

Engelberger

Thalhammer

et al. 2021

In Vivo

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Background/Aim: Patients after kidney transplants are at risk of cardiovascular morbidity. An elevated resistance index (RI) is associated with renal graft failure, while a decreased RI can be due to a renal artery stenosis. The RI can also be measured in the carotid artery. Whether a correlation between intrarenal RI after kidney transplant in adult patients and the RI of the internal carotid artery exists is still unclear. Patients and Methods: In this prospective cross-sectional study, RI of kidney transplants and of the internal carotid artery were measured with duplex sonography. Carotid intima-media thickness as well as the Framingham risk score and the Augmentation index, all known markers of atherosclerosis, were assessed. Correlations between the RI in Carotid artery and the RI of the kidney transplant were based on Spearmen test with the level of significance set at p<0.05. Results: Ninety-eight consecutive patients [60% male, mean age of 48.7 (±15.6)] were included. The mean interval after transplantation was 27.5 (±8.5) months and mean serum creatinine was 308 (±220.3) mmol/ml The RI of the internal carotid artery and the renal transplant were significantly correlated (p<0.05). A correlation between the RIs and the Augmentation Index was found. Conclusion: The RI of the kidney transplant is correlated with the RI of the carotid artery and to markers of general atherosclerosis. This observation may be helpful to identify patients after kidney transplant with higher risk for cardiovascular events and gain indirect information on transplant renal artery stenosis.Kidney transplant is the most frequently performed organ transplant (1). Computed tomography (CT) and coronary Angio-CT are used for risk stratification in kidney transplant candidates for risk stratification before transplantation (2). It is the treatment of choice in end-stage renal disease (ESRD) and is ideally performed before initiation of hemodialysis (3). It is also more cost-effective than long-term dialysis (4). Color-coded Doppler sonography (CCDS) is part of the postoperative surveillance (5). The surveillance may start as early as during, but should be initiated immediately after transplant (6). Besides the diagnosis of arterial or venous obstruction, the intrarenal vascular resistance, called Resistance Index (RI) is measured (7). While the RI can be difficult to measure in orthotope kidneys it is often easier to assess in the more superficial transplant in the iliac fossa. Nonetheless, accessibility can be limited due to different factors such as pain, obesity, flatulence amongst others. The RI has been a proven to be sensitive marker of graft dysfunction, but is unspecific (8). The RI of the kidney transplant adapts rapidly to the host ( 9). An elevated RI of 0.80 (normal range=0.6-0.7) or higher indicates an unfavorable prognosis of renal function as well as increased mortality (10). A decreased RI can be a sign for a renal stenosis (11). RI measurement is observer dependent (12). There is a significant association between an incr...

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Section: Discussioncontrasting

confidence: 66%

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation

Köger

Engelberger

Thalhammer

et al. 2021

In Vivo

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“…We could also show that there is a positive association between mean kidney transplant RI and mean internal carotid artery RI. We could not show a positive correlation between renal function and RI as described in former studies [11,30]. Only patients with a low FRS had a signi cant correlation with the transplant RI in our cohort, while Heine et al found that renal transplant recipients with a high cardiovascular risk had increased RIs.…”

Section: Discussioncontrasting

confidence: 65%

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation.

Köger

Engelberger²,

Wüthrich

et al. 2021

Preprint

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Background Patients after kidney transplant are at risk of cardiovascular morbidity. Surveillance of kidney transplants is mandatory to ensure a maximal transplant lifespan. Renal function is measured by levels of creatinine (clearance) while morphological aspects and other parameters like the kidney-size and Resistance Index are assessed with Duplex sonography. An elevated Resistance Index is associated with renal graft failure. The Resistance Index can also be measured in the carotid artery. It is uncertain whether a correlation between intrarenal RI after kidney transplant and the RI of the internal carotid artery exists. Material and Methods Resistance index of kidney transplants and of the carotid artery were measured with duplex sonography in adult patients after kidney transplant. Carotid intima-media thickness as well as the Framingham risk score and the Augmentation index, all known markers of atherosclerosis, were assessed. Statistical analysis was performed with STATA. Continuous data were expressed as means +/- standard deviation and compared by Kruskal-Wallis Test. Correlations between the RI in Carotid artery and the RI of the kidney transplant were based on Spearmen test with the level of significance set at p < 0.05. Results 98 consecutive patients (60% male, mean age of 48.7 (+/-15.6)) were included. Mean interval after transplantation was 27.5 (+/- 8.5) months and the mean serum creatinine was 308 (+/- 220.3) mmol/L. The RI of the internal carotid artery and the renal transplant were significantly correlated (p < 0.05). A strong correlation between the RIs and the Augmentation Index (AIx) was found. Conclusion The RI of the kidney transplant is correlated with the RI of the carotid artery and to markers of general atherosclerosis. This observation may be helpful to identify patients after kidney transplant with higher risk for cardiovascular events.

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“…Conversely, with colour Doppler, it is sometimes not possible to evaluate if a visualized vascular disturbance like a reduced perfusion of one renal pole is significant or due to technical limitations. It is known that diagnostic findings in Doppler ultrasound are limited when the allograft lies deep within the iliac fossa [ 33 ]. In these cases, CES can differentiate between a real and an apparent perfusion defect and spares a further examination by MRI or CT (Figure 4 ).…”

Section: Indications For Ces In Kidney Transplant Recipientsmentioning

confidence: 99%

When is contrast-enhanced sonography preferable over conventional ultrasound combined with Doppler imaging in renal transplantation?

et al. 2015

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Conventional ultrasound in combination with colour Doppler imaging is still the standard diagnostic procedure for patients after renal transplantation. However, while conventional ultrasound in combination with Doppler imaging can diagnose renal artery stenosis and vein thrombosis, it is not possible to display subtle microvascular tissue perfusion, which is crucial for the evaluation of acute and chronic allograft dysfunctions. In contrast, real-time contrast-enhanced sonography (CES) uses gas-filled microbubbles not only to visualize but also to quantify renal blood flow and perfusion even in the small renal arterioles and capillaries. It is an easy to perform and non-invasive imaging technique that augments diagnostic capabilities in patients after renal transplantation. Specifically in the postoperative setting, CES has been shown to be superior to conventional ultrasound in combination with Doppler imaging in uncovering even subtle microvascular disturbances in the allograft perfusion. In addition, quantitative perfusion parameters derived from CES show predictive capability regarding long-term kidney function.

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Intrarenale Dopplerflußanalysen bei nierentransplantierten Patienten mit stabiler Transplantatfunktion

Cited by 22 publications

References 0 publications

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation

Association of Intrarenal Resistance Index and Systemic Atherosclerosis After Kidney Transplantation.

When is contrast-enhanced sonography preferable over conventional ultrasound combined with Doppler imaging in renal transplantation?

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