Utilization of Carbon Dioxide Angiography and Percutaneous Balloon Angioplasty for Treatment of Transplant Renal Artery Stenosis.

BACKGROUND: Transplant renal artery stenosis (TRAS) may lead to graft dysfunction and failure. Progressive deterioration of renal allograft function may be exacerbated by contrast-induced nephrotoxicity during iodine contrast administration for renovascular imaging of allografts. We present our institutional experience of endovascular management for TRAS using CO2 digital subtraction angiography (CO2-DSA) and balloon angioplasty to manage failing renal transplants. METHODS: Four patients with renal allografts from March 2017-May 2018 were referred for graft dysfunction and pending renal transplant failure. Indications for referral included refractory hypertension, decreasing renal functioning, and elevated renovascular systolic velocities. RESULTS: Median age of the four patients was 41.5 years (22-60 years). There were two male and female patients. Chronic hypertension and type 2 diabetes mellitus were the most common comorbidities. An average total of 75 mL of CO2 was used, supplemented with 17.4 mL of iodinated contrast. All patients had improvements in renal function following intervention with a mean decrease in systolic and diastolic blood pressure of 25.8% and 21.4%, respectively. We also observed a mean decrease of BUN by 13.6% and creatinine by 37.4%. Additionally, eGFR increased by 37.7%. All allografts survived after surgery, and only one patient required repeat angioplasty for recurrence. CONCLUSIONS: CO2-DSA with balloon angioplasty can be successfully utilized to salvage deteriorating kidney allograft function in patients with TRAS.

Revascularization of atherosclerotic renal artery stenosis for chronic heart failure versus acute pulmonary oedema.

AIM: The aim of the study is to determine whether the apparent benefit of revascularization of renal artery stenosis for 'flash' pulmonary oedema extends to heart failure patients without a history of prior acute pulmonary oedema. METHODS: A prospective study of patients with renal artery stenosis and heart failure at a single centre between 1 January 1995 and 31 December 2010. Patients were divided into those with and without previous acute pulmonary oedema/decompensation. Survival analysis compared revascularization versus medical therapy in each group using Cox regression adjusted for age, estimated glomerular filtration rate, blood pressure and co-morbidities. RESULTS: There were 152 patients: 59% male, 36% diabetic, age 70 ± 9 years, estimated glomerular filtration rate 29 ± 17 mL/min per 1.73 m2 ; 52 had experienced previous acute pulmonary oedema (34%), whereas 100 had no previous acute pulmonary oedema (66%). The revascularization rate was 31% in both groups. For heart failure without previous acute pulmonary oedema, the hazard ratio for death after revascularization compared with medical therapy was 0.76 (0.58-0.99, P = 0.04). In heart failure with previous acute pulmonary enema, the hazard ratio was 0.73 (0.44-1.21, P = 0.22). For those without previous acute pulmonary oedema, the hazard ratio for heart failure hospitalization after revascularization compared with medical therapy was 1.00 (0.17-6.05, P = 1.00). In those with previous acute pulmonary oedema, it was 0.51 (0.08-3.30, P = 0.48). CONCLUSION: The benefit of revascularization in heart failure may extend beyond the current indication of acute pulmonary oedema. However, findings derive from an observational study.

Mesenchymal stem cells improve medullary inflammation and fibrosis after revascularization of swine atherosclerotic renal artery stenosis.

Atherosclerotic renal artery stenosis (ARAS) raises blood pressure and can reduce kidney function. Revascularization of the stenotic renal artery alone does not restore renal medullary structure and function. This study tested the hypothesis that addition of mesenchymal stem cells (MSC) to percutaneous transluminal renal angioplasty (PTRA) can restore stenotic-kidney medullary tubular transport function and attenuate its remodeling. Twenty-seven swine were divided into three ARAS (high-cholesterol diet and renal artery stenosis) and a normal control group. Six weeks after ARAS induction, two groups were treated with PTRA alone or PTRA supplemented with adipose-tissue-derived MSC (10 × 10(6) cells intra-renal). Multi-detector computed tomography and blood-oxygenation-level-dependent (BOLD) MRI studies were performed 4 weeks later to assess kidney hemodynamics and function, and tissue collected a few days later for histology and micro-CT imaging. PTRA effectively decreased blood pressure, yet medullary vascular density remained low. Addition of MSC improved medullary vascularization in ARAS+PTRA+MSC and increased angiogenic signaling, including protein expression of vascular endothelial growth-factor, its receptor (FLK-1), and hypoxia-inducible factor-1α. ARAS+PTRA+MSC also showed attenuated inflammation, although oxidative-stress remained elevated. BOLD-MRI indicated that MSC normalized oxygen-dependent tubular response to furosemide (-4.3 ± 0.9, -0.1 ± 0.4, -1.6 ± 0.9 and -3.6 ± 1.0 s(-1) in Normal, ARAS, ARAS+PTRA and ARAS+PTRA+MSC, respectively, p<0.05), which correlated with a decrease in medullary tubular injury score (R(2) = 0.33, p = 0.02). Therefore, adjunctive MSC delivery in addition to PTRA reduces inflammation, fibrogenesis and vascular remodeling, and restores oxygen-dependent tubular function in the stenotic-kidney medulla, although additional interventions might be required to reduce oxidative-stress. This study supports development of cell-based strategies for renal protection in ARAS.

Interventional treatment of hypertension: a new paradigm.

Hypertension is thought to contribute to more than 7 million deaths worldwide each year and contributes to the development of atherosclerotic lesions that lead to myocardial infarction and stroke. While lifestyle modifications (diet, exercise, weight loss) and pharmacotherapy have been proven to be effective in the treatment of hypertension, as many as half of patients have uncontrolled BP and remain at risk for elevated cardiovascular morbidity and mortality. The main physiologic targets for interventional treatment include alteration of blood flow to the kidney, activation of the carotid baroreflex system, and modification of the renal sympathetic nervous system. The results of prior studies and new studies of interventional treatments of resistant hypertension are covered in this review.

Long-term safety and efficacy of renin-angiotensin blockade in atherosclerotic renal artery stenosis.

PURPOSE: The activation of the renin-angiotensin-aldosterone system caused by renal ischaemia in atherosclerotic renal artery stenosis (ARAS) may be responsible for serious cardiovascular and renal consequences. The aim of the study was to assess the long-term safety, tolerability and outcomes of the use of angiotensin I-converting enzyme inhibitors (ACEis) and angiotensin receptor blockers (ARBs) in patients with ARAS. METHODS: Thirty-six patients with angiographically defined ARAS (managed either with revascularization or only with medical treatment) were prospectively assessed for the safety, tolerability and outcomes of the use of ACEis or ARBs. RESULTS: The mean period of follow-up was 88.9 ± 37.8 months. A statistically significant reduction in systolic and diastolic blood pressure was recorded over time (P < 0.001). While estimated glomerular filtration rate remained almost stable during the study period (0.816), nuclear EDTA-GFR showed a significant reduction over time (P = 0.03). Mean time from diagnosis/intervention to end-stage renal disease for the cohort of 36 patients was 165.38 ± 13.62 months. Mean overall patient survival was 135.36 ± 15.25 months, with fourteen deaths (38.8%) occurring during the observational period. ACEi/ARB therapy was discontinued transiently in only 4 subjects. CONCLUSIONS: The use of ACEis/ARBs is safe and effective in patients with ARAS independently of any parameters.

Water-soluble polyvinyl alcohol microspheres for temporary embolization: development and in vivo characteristics in a pig kidney model.

PURPOSE: To preliminarily examine whether solubility of water-soluble polyvinyl alcohol (PVA) microspheres in blood plasma changes in proportion to their degrees of saponification. The study also examined their feasibility as a temporary embolic agents in the pig renal artery. MATERIALS AND METHODS: Three types of PVA microspheres with the degrees of saponification of 97 mol% (S97), 98 mol% (S98), and 99 mol% (S99) were prepared. Seven kidneys in seven miniature pigs were embolized and divided into three groups so there would be at least two kidneys for each type of PVA. One animal in each group was euthanized immediately after angiography at 3 hours after embolization and the other one at 7 days after. In addition, one animal embolized with S99 microspheres was euthanized at 21 days after embolization. RESULTS: With S97 microspheres, the vascular network had recovered to the preembolic state by 3 hours after embolization. With S98 microspheres, blood flow in the third-order branch had been restored in the same period. With S99 microspheres, the second- and lower order branches remained occluded until 21 days. Histopathologic specimens harvested at 3 hours revealed only a trace of PVA for S97 microspheres. With S98 microspheres, the vascular lumen was still found to be filled with PVA gel. With S99 microspheres, swollen microspheres densely filled the vascular lumen even on day 21. CONCLUSIONS: Dissolution process in vitro and the duration of arterial occlusion in vivo were possibly related to the degree of saponification of PVA. This result may support feasibility of PVA microspheres as a temporary embolic agent.

Arteritis de Takayasu: caso clínico y seguimiento por 23 años / Takayasu arteritis: case-report and outcome in 23 years

La arteritis de Takayasu es una vasculitis granulomatosa, rara en pediatría, que afecta a la arteria aorta y grandes vasos, produciendo hipertensión arterial y alteración de los pulsos. Nuestro objetivo es presentar a una paciente diagnosticada a los 5 meses de edad y analizar los aspectos clínicos, de diagnóstico, tratamiento y seguimiento de esta enfermedad. Caso Clínico: Paciente de 23 años de edad sexo femenino, cuyo diagnóstico de Arteritis de Takayasu fue hecho en la época de lactante, encontrando en ella hipertensión arterial severa, diferencia de presiones en extremidades superiores, y estenosis de aorta y arterias renales. Se muestra la evolución desde el punto de vista clínico y de imágenes, destacando la importancia actual de la angio resonancia para el control de las estenosis arteriales y de la ecografía para el control de crecimiento renal. Se discute, de acuerdo a la literatura al alcance, respecto al modo de seguimiento de la actividad de la enfermedad, especialmente en relación al hemograma y velocidad de eritrosedimentación. Se analiza el tratamiento con esteroides y otros inmunosupresores, como Azatioprina y Metotrexato, así como el tiempo a usar estos medicamentos y las indicaciones, cuando corresponde, de cirugía y/o angioplastía percutánea. Conclusión: Aunque se trata de una patología poco frecuente, hay que considerarla en los niños hipertensos severos; es importante tomar las presiones en las 4 extremidades, así como los pulsos, y si es necesario debe realizarse el estudio angiográfico, el cual actualmente es posible realizarlo en forma no invasiva con Angio-Resonancia y/o Angio-TAC, con buenos resultados. El tratamiento médico, fundamentalmente con corticoides, es efectivo en la mayoría de los casos y la cirugía debe reservarse a aquellos casos en que exista riesgo de oclusión de alguna de las grandes arterias.

Hypertension and renal artery stenosis: a complex clinical scenario.

Hypertension remains the most common reason for patients to visit physicians in the United States. Although awareness of hypertension among patients continues to increase, adequate control of hypertension remains poor. In addition, as the population of patients with hypertension ages, atherosclerosis becomes increasingly prevalent. Atherosclerotic renal artery stenosis is the most common secondary cause of hypertension and can cause hypertension to be difficult to control. Atherosclerotic renal artery stenosis may also result in chronic renal insufficiency. The physician must be aware of the clinical scenarios in which renal artery stenosis may occur, methods of diagnosis, and indications for intervention.

[Arterial hypertension with hypokalemia]. / Ipertensione arteriosa con ipopotassiemia.

After a careful review of the literature on physiopathological role of the renin-angiotensin-aldosterone system in cases of arterial hypertension with hypokalaemia, a simple diagnostic procedure is suggested to differentiate between this and secondary hypertensions which, though few, are often curable. Three clinical cases examined in the medical department of Casalpusterlengo Hospital are presented in which the study of the renin-angiotensin system proved decisive for a correct diagnosis of the hypertension.

Percutaneous transluminal angioplasty for treatment of renovascular hypertension.

Four patients with typical renovascular hypertension due to atherosclerotic stenosis (3 patients) and near occlusion (one patient) were treated with percutaneous transluminal angioplasty (PTA). Two patients had malignant hypertension by clinical standards. All had significant reduction in blood pressure following angioplasty, resulting in either a normotensive state, or management with significantly less antihypertensive medication. Patency and normal renin levels were achieved within two months in 2 patients. Clinical follow-up documented continued reduction in blood pressure. Advantages of the procedure include local anesthesia, relatively little discomfort, repeatability, and the fact that surgery is not precluded if angioplasty is unsuccessful.