Treatment of atherosclerotic renal artery stenosis: time for a new approach

Diagnosis and Treatment of Renal Artery Stenosis in China in the Era of Donation After Cardiac Death

Background

The aim of this study was to investigate the clinical features and treatment strategies of transplant renal artery stenosis (TRAS) with kidneys from donation after cardiac death (DCD).

Material/Methods

We collected the clinical data of donors and recipients of single-center DCD-induced TRAS from January 2015 to June 2017.

Results

All the 8 cases of TRAS were from hypertensive cerebrovascular accident DCD-originated kidneys. The mean donor age was 53.5 (45~57) years, with mean BMI 27.8 (26.4~32.3) kg/m², atherosclerosis index 5.8 (4.9~7.0), and renal atherosclerotic plaque. Clinical features of TRAS were: refractory hypertension with elevated serum creatinine >50%, and negative urine protein and occult blood. Ultrasound of transplanted kidneys showed renal blood flow index 0.49 (0.43~0.55). Angiography confirmed the diagnosis of renal artery trunk or secondary branch stenosis. There were 2 cases of moderate stenosis and 6 cases of severe stenosis. Six patients underwent stent implantation and 2 patients underwent balloon dilatation. Seven patients had serum creatinine recovery after interventional therapy during follow-up. The transplanted kidney of 1 patient ruptured 6 h after interventional therapy and was then resected.

Conclusions

The incidence of TRAS with hypertensive cerebrovascular accident DCD-originated kidneys is relatively high, which is a warning to kidney transplant physicians. Digital subtraction angiography (DSA) is the most reliable diagnostic means of TRAS and can be performed concurrently with intervention therapy. If the donor has severe atherosclerosis, plaques that are visible to the unaided eye in the renal artery trunk should be removed as completely as possible.

Blood pressure decreases after revascularization in atherosclerotic renal artery disease: A cohort study based on a multidisciplinary meeting

Background

In atherosclerotic renal artery disease, the benefit of revascularization is controversial. A clinical decision-making process based on a multidisciplinary meeting was formalized in the Lyon university hospital.

Objectives

To investigate whether this decisional process ensured a clinical benefit to patients assigned to renal revascularization.

Methods

Single-centre retrospective cohort study, including patients diagnosed from April 2013 to February 2015 with an atherosclerotic renal artery disease with a peak systolic velocity >180cm/s. For each patient, the decision taken in multidisciplinary meeting (medical treatment or revacularization) was compared to the one guided by international guidelines. Blood pressure values, number of antihypertensive medications, presence of an uncontrolled or resistant hypertension, and glomerular filtration rate at one-year follow-up were compared to baseline values. Safety data were collected.

Results

Forty-nine patients were included: 26 (53%) were assigned to a medical treatment and 23 (47%) to a renal revascularization. Therapeutic decision was in accordance with the 2013 American Health Association guidelines and with the 2017 European Society of Cardiology guidelines for 78% and 22% of patients who underwent revascularization, respectively. Patients assigned to revascularization presented a significant decrease in systolic blood pressure (-23±34mmHg, p = 0.007), diastolic blood pressure (-12±18mmHg, p = 0.007), number of antihypertensive medications (-1.00±1.03, p = 0.001), and number of uncontrolled or resistant hypertension (p = 0.022 and 0.031) at one-year follow-up. Those parameters were not modified among patients assigned to medical treatment alone. There was no grade 3 adverse event.

Conclusion

Based on a multidisciplinary selection of revascularization indications, patients on whom a renal revascularization was performed exhibited a significant improvement of blood pressure control parameters with no severe adverse events.

Disease or adaptation: another look at the practice of medicine

The practice of medicine has changed considerably over the past few decades and is now focusing more and more on early intervention strategies. As a result, we tend to consider pre-symptomatic abnormalities, however small, already as a potential target for treatment. In this viewpoint, we argue that we should put more emphasis on pathophysiological thinking as many of the so-called early abnormalities may, in fact, reflect adaptive mechanisms rather than disease. This view should influence medical care and education, emphasizing the importance of knowledge of pathophysiology.

[Management of atherosclerotic renal-artery stenosis in 2016]

Endovascular revascularization as treatment of atherosclerotic renal-artery stenosis (aRAS) is controversial since 3 large and multicentric randomised trials (CORAL, ASTRAL, STAR) failed to prove the superiority of percutaneous transluminal renal-artery stenting (PTRAS) over medical treatment only (MT). However, considering the multiple bias of these trials, among which questionable inclusion criterias, these results must be extrapolated in clinical practice with caution. New pathophysiological data have been helping to understand why restoring blood flow does not necessarily lead to kidney function improvement. Today, the diagnostic approach must in one hand confirm the artery stenosis and on the other hand assess its severity and impact on the kidney. Therapeutic options still lie on the American guidelines published in 2006, since no study data can be reasonably used in everyday practice. However, particular sub-groups of patients who could benefit from revascularisation have been identified through recent cohort studies. Further prospective studies are needed in order to confirm the superiority of PTRAS in these populations. Meanwhile, multidisciplinary approach should be promoted, in order to provide the best treatment for each patient.

Atherosclerotic Renal Artery Stenosis and Hypertension: Pragmatism, Pitfalls, and Perspectives

For many years and even decades, a diagnostic work-up to look for a secondary form of hypertension, particularly of renovascular origin, has been a central tenet in medicine. Atherosclerotic renal artery stenosis is considered the most common cause of renovascular hypertension. However, advances in understanding the complex pathophysiology of this condition and the recently documented futility of renal revascularization bring into question whether atherosclerotic renal artery stenosis truly causes "renovascular hypertension." From a clinical point of view, a clear distinction should be made between hypertension associated with atherosclerotic renal artery stenosis and hypertension caused by renal artery stenosis-induced activation of the renin-angiotensin-aldosterone system. Most patients with atherosclerotic renal artery stenosis do not have a form of hypertension that is remediable or improved by angioplasty; to expose them to the cost, inconvenience, and risk of a diagnostic work-up add up to little more than a wild goose chase. However, with very few exceptions, medical therapy with antihypertensives and statins remains the cornerstone for the management of patients with atherosclerotic renal artery stenosis and hypertension.

The use of intrarenal Doppler ultrasonography as predictor for positive outcome after renal artery revascularization

Whether patients with renal artery stenosis should undergo therapeutic revascularization is controversial. In this retrospective study, we evaluated prognostic intrarenal Doppler ultrasound parameters that might have a predictive value for a beneficial response after renal revascularization. From January 2003 until December 2012, all renovascular interventions for renal artery stenosis were analyzed. The resistive index and the maximal systolic acceleration were determined by Doppler ultrasonography prior to intervention. Thirty-two patients who underwent a renal revascularization procedure were included: 13 combined positive responders and 19 combined non-responders. The combined positive responders had a significant lower resistive index than the combined non-responders (0.5 vs. 0.6, P = 0.001) and a significant lower maximal systolic acceleration (1.0 vs. 3.8, P = 0.001) before revascularization. A prediction model (RI ≤ 0.5 and ACC_max ≤ 1.3 m/s²) was formulated to identify a subgroup that benefits from renal revascularization. This model has an expected sensitivity of 69% and specificity of 89% for improvement in renal function and/or blood pressure after revascularization. The non-invasive intrarenal Doppler ultrasound parameters resistive index and maximal systolic acceleration can be used as tools to predict improvement in renal function and/or blood pressure after revascularization of renal artery stenosis. The clinical value of this prediction model should be evaluated in a prospective trial.

Treatment of hypertension in patients with atherosclerotic renal artery stenosis, updated

Atherosclerotic renal artery stenosis (ARAS) is a fairly common disease of elderly patients and is discovered incidentally in 6.3% to 38% in those undergoing diagnostic cardiac or abdominal angiography. Of those patients diagnosed with renal artery stenosis, in 90% it is due to ARAS and in 10% to fibromuscular dysplasia (FMD), which is a disease of younger persons, mostly females. Renal artery stenosis is frequently associated with hypertension and impaired renal function, and it is perceived by many physicians as the primary cause of hypertension and renal failure. For this reason, they believe that hypertension and renal failure can be significantly improved by performing percutaneous transluminal renal angioplasty (PTRA) with a stent placement as the preferred treatment instead of medical therapy. This practice has led to an increase in angioplasties, especially by interventional cardiologists who are familiar with the procedure. However, the results of several randomized studies comparing interventional therapy with medical therapy have shown no significant difference between the 2 treatment modalities in blood pressure reduction and prevention and in worsening of renal function. Similar results have been found by nonrandomized trials in patients treated selectively with PTRA. For this review, a Medline search was conducted of the English-language literature from January 1, 2006 to December 31, 2013, using the terms atherosclerotic renal artery stenosis and renal artery stenosis; 6 pertinent randomized studies were selected. These studies, with collateral literature, are discussed in this review. The data show that PTRA with stent plus medical therapy in patients with ARAS is not superior to medical therapy alone in lowering the blood pressure, in preventing renal function deterioration, and in reducing all-cause mortality, cardiovascular morbidity or mortality, and strokes.

Radionuclides in nephrourology, Part 2: pitfalls and diagnostic applications

Radionuclide renal scintigraphy provides important functional data to assist in the diagnosis and management of patients with a variety of suspected genitourinary tract problems, but the procedures are underutilized. Maximizing the utility of the available studies (as well as the perception of utility by referring physicians) requires a clear understanding of the clinical question, attention to quality control, acquisition of the essential elements necessary to produce an informed interpretation, and production of a report that presents a coherent impression based on data contained in the report and that specifically addresses the clinical question. To help achieve these goals, part 1 of this review addressed the available radiopharmaceuticals, quality control, and quantitative indices, including the measurement of absolute and relative renal function. Part 2 assumes familiarity with part 1 and focuses on the common clinical indications of suspected obstruction and renovascular hypertension; part 2 also summarizes the status of radionuclide renal imaging in the evaluation of the transplanted kidney and the detection of infection, discusses potential pitfalls, and concludes with suggestions for future research. The series of SAM questions accompanying parts 1 and 2 has been designed to reinforce and extend points made in the review. Although the primary focus is the adult patient, aspects of the review also apply to the pediatric population.

Secondary arterial hypertension: when, who, and how to screen?

Secondary hypertension refers to arterial hypertension due to an identifiable cause and affects ∼5-10% of the general hypertensive population. Because secondary forms are rare and work up is time-consuming and expensive, only patients with clinical suspicion should be screened. In recent years, some new aspects gained importance regarding this screening. In particular, increasing evidence suggests that 24 h ambulatory blood pressure (BP) monitoring plays a central role in the work up of patients with suspected secondary hypertension. Moreover, obstructive sleep apnoea has been identified as one of the most frequent causes. Finally, the introduction of catheter-based renal denervation for the treatment of patients with resistant hypertension has dramatically increased the interest and the number of patients evaluated for renal artery stenosis. We review the clinical clues of the most common causes of secondary hypertension. Specific recommendations are given as to evaluation and treatment of various forms of secondary hypertension. Despite appropriate therapy or even removal of the secondary cause, BP rarely ever returns to normal with long-term follow-up. Such residue hypertension indicates either that some patients with secondary hypertension also have concomitant essential hypertension or that irreversible vascular remodelling has taken place. Thus, in patients with potentially reversible causes of hypertension, early detection and treatment are important to minimize/prevent irreversible changes in the vasculature and target organs.