Update and review of renal artery stenosis

Deep-learning-based renal artery stenosis diagnosis via multimodal fusion

PURPOSE

Diagnosing Renal artery stenosis (RAS) presents challenges. This research aimed to develop a deep learning model for the computer-aided diagnosis of RAS, utilizing multimodal fusion technology based on ultrasound scanning images, spectral waveforms, and clinical information.

METHODS

A total of 1485 patients received renal artery ultrasonography from Peking Union Medical College Hospital were included and their color doppler sonography (CDS) images were classified according to anatomical site and left-right orientation. The RAS diagnosis was modeled as a process involving feature extraction and multimodal fusion. Three deep learning (DL) models (ResNeSt, ResNet, and XCiT) were trained on a multimodal dataset consisted of CDS images, spectrum waveform images, and individual basic information. Predicted performance of different models were compared with senior physician and evaluated on a test dataset (N = 117 patients) with renal artery angiography results.

RESULTS

Sample sizes of training and validation datasets were 3292 and 169 respectively. On test data (N = 676 samples), predicted accuracies of three DL models were more than 80% and the ResNeSt achieved the accuracy 83.49% ± 0.45%, precision 81.89% ± 3.00%, and recall 76.97% ± 3.7%. There was no significant difference between the accuracy of ResNeSt and ResNet (82.84% ± 1.52%), and the ResNeSt was higher than the XCiT (80.71% ± 2.23%, p < 0.05). Compared to the gold standard, renal artery angiography, the accuracy of ResNest model was 78.25% ± 1.62%, which was inferior to the senior physician (90.09%). Besides, compared to the multimodal fusion model, the performance of single-modal model on spectrum waveform images was relatively lower.

CONCLUSION

The DL multimodal fusion model shows promising results in assisting RAS diagnosis.

Severe acute kidney injury in a patient with renal artery stenosis of a single-functioning kidney: A case report of rapid normalisation of the renal function after percutaneous transluminal angioplasty with stent placement

Revascularisation of renal arterial stenosis in acute settings, such as uncontrolled arterial hypertension, flash pulmonary oedema and/or acute renal failure, has shown controversial results in observational and prospective studies. Current guidelines do not recommend revascularisation in the occurrence of renal failure as revascularisation and best medical treatment have shown similar long-term outcomes on renal function. We describe a case of acute degradation of the renal function (with oligo-anuria and a peak creatinine of 462 µmol/L) after the re-introduction of an angiotensin-II receptor blocker (irbesartan) in a 66-year-old Caucasian diabetic male patient with bilateral renal stenosis and a right-sided single-functioning kidney, with a rapid improvement of the renal function which normalized 5 days after percutaneous angioplasty and stenting of the right renal artery.

Case report: Multiple arterial stenoses induced by autosomal-recessive hypophosphatemic rickets type 2 associated with mutation of ENPP1: a case study

Ectonucleotide pyrophosphatase/phosphodiesterase 1 (ENPP1)-related multiple arterial stenoses is a rare clinical syndrome in which global arterial calcification begins in infancy, with a high probability of early mortality, and hypophosphatemic rickets develops later in childhood. The vascular status of an ENPP1-mutated patient when they enter the rickets phase has not been thoroughly explored. In this study, we presented a case of an adolescent with an ENPP1 mutation who complained of uncontrolled hypertension. Systematic radiography showed renal, carotid, cranial, and aortic stenoses as well as random calcification foci on arterial walls. The patient was incorrectly diagnosed with Takayasu's arteritis, and cortisol therapy had little effect on reducing the vascular stenosis. As a result, phosphate replacement, calcitriol substitution, and antihypertensive medication were prescribed, and the patient was discharged for further examination. This research presented the vascular alterations of an ENPP1-mutanted patient, and while there is less calcification, intimal thickening may be the primary cause of arterial stenosis.

Dynamic changes of renal cortical blood perfusion before and after percutaneous transluminal renal artery stenting in patients with severe atherosclerotic renal artery stenosis

BACKGROUND

This study aims to observe the dynamic changes of renal artery (RA) disease and cortical blood perfusion (CBP) evaluated by contrast-enhanced ultrasound (CEUS) after percutaneous transluminal renal artery stenting (PTRAS) in patients with severe atherosclerotic renal artery stenosis (ARAS) and to analyze the relationship between CBP and prognosis.

METHODS

This was a single-center retrospective cohort study. A total of 98 patients with unilateral severe ARAS after successful PTRAS in Beijing Hospital from September 2017 to September 2020 were included. According to renal glomerular filtration rate (GFR) detected by radionuclide imaging at 12 months after PTRAS, all patients were divided into the poor prognosis group (n = 21, GFR decreased by ≥20% compared with baseline) and the control group (n = 77, GFR decreased by < 20% or improved compared with baseline). Renal artery stenosis was diagnosed by digital subtraction angiography, and renal CBP was evaluated by CEUS using TomTec Imaging Systems (Germany) before PTRAS, at 6 months and 12 months after discharge. The receiver operating characteristic (ROC) curve with area under the curve (AUC) was used to analyze the predictive value of CBP parameters, including area under ascending curve (AUC1), area under the descending curve (AUC2), rising time (RT), time to peak intensity (TTP), maximum intensity (IMAX), and mean transit time (MTT) for poor prognosis.

RESULTS

Among the 98 patients, there were 52 males (53.1%), aged 55-74 years old, with an average age of 62.1 ± 8.7 years, and an average artery stenosis of 82.3 ± 12.9%. The poor prognosis group was associated with significantly increased incidence of diabetes (76.2% vs. 41.6%), and lower levels of GFR of the stenotic kidney (21.8 mL/min vs. 25.0 mL/min) and total GFR (57.6 mL/min vs. 63.7 mL/min) (all P < 0.05), compared with the control group (P < 0.05). In addition, the rate of RA restenosis was significantly higher in the poor prognosis group than in the control group (9.5% vs. 0, χ2 = 9.462, P = 0.002). Compared with the control group, the poor prognosis group was associated with significantly decreased baseline AUC1 and AUC2, and extended duration of TTP and MTT (P < 0.05). At 6 months and 12 months of follow-up, patients in the control group were associated with markedly increased AUC1, AUC2, and IMAX, and shorter duration of RT and MTT (P < 0.05). The ROC curve showed that the predictive values of AUC1, AUC2, RT, TTP, IMAX, and MTT for poor prognosis were 0.812 (95% CI: 0.698-0.945), 0.752 (95% CI: 0.591-0.957), 0.724 (95% CI: 0.569-0.961), 0.720 (95% CI: 0.522-0.993), 0.693 (95% CI: 0.507-0.947), and 0.786 (95% CI: 0.631-0.979), respectively.

CONCLUSIONS

Preoperative renal CBP in severe ARAS patients with poor prognosis is significantly reduced, and does not show significant improvement after stent treatment over the first year of follow-up. The parameter AUC1 may be a good predictor for renal dysfunction after PTRAS in severe ARAS patients. Trial Registration: ChiCTR.org.cn, ChiCTR1800016252.

Renovascular Hypertension in Chronic Hemodialytic Patient

Background: Hypertension is a major contributor to the development of chronic kidney disease. Data in Indonesia, hypertension is still the most comorbid disease in CKD patients on dialysis (51%). Hypertension in CKD on dialysis patients is common and often uncontrolled.  Renovascular hypertension is the most common cause of secondary hypertension. Diagnosis and treatment of RAS is very important, because it can accelerate the achievement of blood pressure targets, reduce the risk and complications due to hypertension. Case Report: A 52-year-old woman with CKD has been undergoing hemodialysis for 2 years. Hypertension that was previously well controlled for 2 years required an increase in antihypertensive therapy from 2 to 4 drugs in recent months. On physical examination the blood pressure 180/90 mmHg, pulse 79 bpm, respiration 20/min, temperature 36.7oC. Conjunctiva looks anemic, cardiomegaly, lungs within normal limits, no ascites and edema in the extremities. On renal artery duplex ultrasound examination, right main renal artery acceleration time 147.65 ms, Peak Systolic Velocity (PSV) 31.9 cm/s. RI 0.69 and left main renal artery acceleration time 120.81 ms, PSV 16.9 cm/s, RI 0.61. There was 20-30% left renal artery stenosis, 80% right renal artery stenosis. A stent was placed on the right renal artery. The patient's condition after PTRA improved, but at the next follow-up, mean systole and diastole 170 mmHg and 80 mmHg, respectively. Patient received 4 antihypertensive therapy. Conclusion: Renal artery stenosis is a disease that consists of a broad spectrum of different entities with different pathophysiologies that require varied approaches to diagnose and treat. Current diagnostic tools include MRA, CTA and renal artery duplex ultrasonography. Patients with renal parenchymal disease are poorer candidates for revascularization.