Total Renal Artery Occlusion: Recovery of Function After Revascularization

Endovascular treatment of renal artery stenosis in Germany: a retrospective analysis of the DEGIR registry 2018-2021

PURPOSE

 To provide an overview of endovascular treatment of renal artery stenosis (RAS) using the data of the Deutsche Gesellschaft für interventionelle Radiologie (DeGIR) quality management system.

MATERIALS AND METHODS

 A retrospective analysis was performed. Pre-, peri- and postprocedural data, technical success rates, complication rates, and clinical success rates at dismissal were examined.

RESULTS

 Between 2018 and 2021, 2134 angiography examinations of the renal arteries were performed: diagnostic angiography in 70 patients (3 %), balloon angioplasty in 795 (37 %), stent implantation in 1166 (55 %) and miscellaneous procedures in 103 (5 %). The lesion length was less than or equal to 5 mm in 1837 patients (87 %), between 5 and 10 mm in 197 (9 %), and between 10 and 20 mm in 62 (3 %). The degree of stenosis was less than 50 % in 156 patients (7 %), greater than 50 % in 239 (11 %), and greater than 70 % in 1472 (70 %). Occlusion was treated in 235 patients (11 %). Symptoms at discharge resolved in 600 patients (29 %), improved in 1012 (49 %), were unchanged in 77 (4 %), and worsened in 5 (0.2 %). Complications were reported in 51 patients (2.5 %) and the mortality rate was 0.15 %.

CONCLUSION

 A substantial number of patients with RAS and occlusions were treated by radiologists in Germany, with high technical success rates and low complication rates. The indication should be determined carefully as the current European guidelines for the treatment of RAS suggest that only carefully selected groups of patients will benefit from recanalizing treatment.

KEY POINTS

  · Carefully selected patient groups may benefit from endovascular treatment of renal artery stenosis.. · Analysis of the DEGIR quality management database shows that treatment of renal artery stenosis was performed by radiologists in Germany with high technical success rates and low complication rates.. · Recanalization even led to symptom improvement in a large proportion of patients with occlusions..

Pickering Syndrome: An Overlooked Renovascular Cause of Recurrent Heart Failure

ABSTRACTRecurring and rapidly developing (flash) pulmonary edema is the hallmark of Pickering syndrome, affecting patients with hypertension and atherosclerotic renal artery stenosis (either bilateral or unilateral) in a solitary functioning kidney, and impaired renal function. We herein report on a series of consecutive patients with recurrent hospital admissions for pulmonary edema, impaired renal function (chronic kidney disease class 4-5), and atherosclerotic bilateral renal artery stenosis, in whom Pickering syndrome had been long neglected. We also describe a streamlined diagnostic strategy entailing little or no need for contrast medium, thus carrying no risks of further worsening of renal function. This allowed us to make the correct diagnosis and opened the way to revascularization by percutaneous transluminal renal angioplasty with stent, which provided swift recovery of kidney function with resolution of pulmonary congestion and long-term pulmonary edema- and dialysis-free survival in all cases. In summary, these findings support the following key messages: (1) considering the diagnosis of Pickering syndrome, followed by searching atherosclerotic renal artery stenosis, is an essential step toward a life-saving revascularization that avoids dialysis and an otherwise poor outcome; and (2) a simplified strategy entailing little or no need for contrast medium, carrying no associated risks of deteriorating renal function, permits the diagnosis of Pickering syndrome.

Case Report: Endovascular Treatment of Chronic Atherosclerotic Renal Artery Total Occlusions with Failed Medical Therapy

Background

Current guidelines generally no longer support revascularization for chronic renal artery occlusive diseases because results from randomized controlled trials favor medical therapy over angioplasty. However, increasing reports indicate that patients with renal artery occlusion (RAO) can benefit from revascularization under certain circumstances.

Case summary

Here, we present a patient with renal artery stenosis (RAS) who does not have refractory hypertension or fit any clinical trial inclusion criteria by far. Medical therapy failed to prevent the progression of RAS in this patient, leading to total occlusion of his right renal artery. This patient had progressive renal insufficiency but recovered renal function after endovascular treatment.

Conclusion

This case demonstrates that angioplasty can be beneficial in selected RAO patients, especially those with residual renal function and collateral perfusion.

Prediction of Split Renal Function Improvement After Renal Artery Stenting by Blood Oxygen Level–Dependent Magnetic Resonance Imaging

Background

The discrepancy between the high technical success rate and the relatively low clinical response rate of renal artery stenting (RAS) raises the importance to identify atherosclerotic renal artery stenosis (ARAS) patients who are most likely to benefit from RAS. This study aimed to investigate the feasibility and accuracy of blood oxygen level-dependent magnetic resonance imaging (BOLD-MRI) in predicting split renal function (SRF) improvement after RAS in patients with ARAS.

Methods

Thirty patients with severe ARAS who were treated with RAS were enrolled. Baseline cortical and medullary R2* values of each kidney were measured by BOLD-MRI, and each patient’s SRF was evaluated by nuclear renal dynamic imaging at baseline and 1-month follow-up.

Results

In total, 35 severe stenotic renal arteries of the 30 patients were analyzed. At 1-month follow-up, 34 kidneys (97.1%) of severe ARAS had acquired SRF. SRF improved in 12 kidneys of 10 patients. The cortical R2* and medullary R2* values in the SRF improvement kidneys were higher than those in the non-improvement kidneys (P ≤ 0.001). The area under the curve of medullary R2* was 0.879 (95% confidence interval [CI] 0.736–1.000). A medullary R2* value ≥29.1 s^–1 was noted to provide good sensitivity (0.833, 95% CI 0.552–0.970) and specificity (0.864, 95% CI 0.667–0.953) in predicting SRF improvement. Medullary R2* value was the only independent predictor of SRF improvement in multivariable analysis (P = 0.034, OR 3.017, 95%CI 1.089–8.358).

Conclusion

This study showed that a BOLD-MRI medullary R2* value ≥29.1 s^–1 was an excellent predictor of SRF improvement in patients with severe ARAS who underwent renal artery stenting.

Atherosclerotic Renovascular Disease: A KDIGO (Kidney Disease: Improving Global Outcomes) Controversies Conference

The diagnosis and management of atherosclerotic renovascular disease (ARVD) is complex and controversial. Despite evidence from the ASTRAL (2009) and CORAL (2013) randomized controlled trials showing that percutaneous renal artery revascularization did not improve major outcomes compared with best medical therapy alone over 3-5 years, several areas of uncertainty remain. Medical therapy, including statin and antihypertensive medications, has evolved in recent years, and the use of renin-angiotensin-aldosterone system blockers is now considered the primary means to treat hypertension in the setting of ARVD. However, the criteria to identify kidneys with renal artery stenosis that have potentially salvageable function are evolving. There are also data suggesting that certain high-risk populations with specific clinical manifestations may benefit from revascularization. Here, we provide an overview of the epidemiology, diagnosis, and treatment of ARVD based on consensus recommendations from a panel of physician experts who attended the recent KDIGO (Kidney Disease: Improving Global Outcomes) Controversies Conference on central and peripheral arterial diseases in chronic kidney disease. Most focus is provided for contentious issues, and we also outline aspects of investigation and management of ARVD that require further research.

Treatment of Refractory Hypertension with Timely Angioplasty in Total Renal Artery Occlusion with Atrophic Kidney

Angioplasty for cases of chronic total occlusion of renal artery with/without atrophic kidney is generally not recommended. We herein report a 57-year-old man who presented with renin-mediated refractory hypertension caused by occlusion of a unilateral renal artery leading to kidney atrophy (length: 69 mm). Angioplasty favorably achieved blood pressure control with normalized renin secretion and enlargement of the atrophic kidney to 85 mm. Timely angioplasty can be beneficial in select patients, even with an atrophic kidney and total occlusion, especially in cases with deterioration of hypertension within six months and the presence of collateral perfusion to the affected kidney.

The Role of Hypoxia in Ischemic Chronic Kidney Disease

A gradually developing reduction in renal blood flow from atherosclerotic renovascular disease results in loss of kidney volume and a decrease in glomerular filtration rate that eventually becomes irreversible. Whether this process fundamentally reflects tissue hypoxia has been difficult to establish. Studies of human renovascular disease have indicated that reductions in blood flow of up to 30% to 40% can be tolerated with preservation of normal oxygenation and structural integrity. These observations are consistent with remarkable stability of poststenotic kidney function during sustained medical antihypertensive drug therapy in moderate renovascular disease. With more severe and sustained reductions, however, cortical oxygenation decreases and the magnitude of medullary hypoxia expands. These changes are associated with increasing renal venous levels of inflammatory cytokines, angiogenic markers, and infiltration of inflammatory cells, including tissue macrophages and T cells. Although restoring large-vessel blood flow can improve oxygenation, some of these processes reflect microvascular rarefication, remain activated, and do not depend on hemodynamic factors alone. Elucidation of tissue injury pathways associated with hypoxia opens the possibility of adjunctive therapeutic measures beyond renal revascularization. These include cell-based regeneration, mitochondrial protection, and/or angiogenic cytokine therapy to restore or preserve renal function in ischemic nephropathy.