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The Journal of Thoracic and... Dec 2014Open thoracoabdominal aortic aneurysm (TAAA) repair traditionally carries substantial perioperative morbidity and mortality, primarily from distal aortic ischemia.... (Review)
Review
OBJECTIVES
Open thoracoabdominal aortic aneurysm (TAAA) repair traditionally carries substantial perioperative morbidity and mortality, primarily from distal aortic ischemia. Advances in surgical techniques, adjuncts, and strategies have greatly improved outcomes.
METHODS
We analyzed outcomes of 1267 open consecutive TAAA repairs between January 2005 and September 2013. We provided cold crystalloid renal perfusion whenever the renal ostia were accessible; according to extent of repair, we selectively used left heart bypass and provided isothermic blood to the celiac axis and superior mesenteric artery. Repair was extensive (Crawford extent I and II) in 717 cases (57%). Left heart bypass was used in 645 (51%) cases, cold crystalloid renal perfusion in 987 (78%), and isothermic visceral perfusion in 318 (25%). Additional patient-specific surgical adjuncts included endarterectomy of renal or visceral vessels, open stent placement within these vessels, or use of both techniques; at least one was used in 447 repairs (35%).
RESULTS
Thirty-day survival was 95% (1198/1267); overall operative mortality was 8% (104/1267). Acute renal dysfunction occurred in 155 (12%), renal failure requiring hemodialysis at hospital discharge in 84 (7%), and bowel ischemia in 9 (<1%). Extent II and III TAAA repairs carried the highest risks of postoperative renal dysfunction and renal failure requiring hemodialysis at hospital discharge.
CONCLUSIONS
Contemporary protective strategies allow open TAAA repair with substantially fewer renal and visceral ischemic complications. Although bowel ischemia is uncommon, renal failure remains a concern, especially in extent II and extent III TAAA repairs. Additional studies are needed to identify and improve renal protection strategies.
Topics: Aortic Aneurysm, Thoracic; Hospital Mortality; Humans; Ischemia; Kidney; Perfusion; Regional Blood Flow; Renal Circulation; Renal Dialysis; Renal Insufficiency; Time Factors; Treatment Outcome; Vascular Surgical Procedures; Viscera
PubMed: 25135232
DOI: 10.1016/j.jtcvs.2014.06.072 -
Seminars in Nephrology Jan 2015The kidney is comprised of heterogeneous cell populations that function together to perform a number of tightly controlled, complex and interdependent processes. Renal... (Review)
Review
The kidney is comprised of heterogeneous cell populations that function together to perform a number of tightly controlled, complex and interdependent processes. Renal endothelial cells contribute to vascular tone, regulation of blood flow to local tissue beds, modulation of coagulation and inflammation, and vascular permeability. Both ischemia and sepsis have profound effects on the renal endothelium, resulting in microvascular dysregulation resulting in continued ischemia and further injury. In recent years, the concept of the vascular endothelium as an organ that is both the source of and target for inflammatory injury has become widely appreciated. Here we revisit the renal endothelium in the light of ever evolving molecular advances.
Topics: Acute Kidney Injury; Endothelial Cells; Endothelium, Vascular; Humans; Ischemia; Kidney; Microvessels; Renal Circulation; Sepsis
PubMed: 25795503
DOI: 10.1016/j.semnephrol.2015.01.010 -
Journal of Vascular Surgery. Venous and... Mar 2018Although nutcracker syndrome (NS) is rare, patients presenting with symptoms or signs and anatomic compression of the left renal vein (LRV) can be considered for... (Review)
Review
OBJECTIVE
Although nutcracker syndrome (NS) is rare, patients presenting with symptoms or signs and anatomic compression of the left renal vein (LRV) can be considered for intervention. Open, laparoscopic, and endovascular techniques have been developed to decrease the venous outflow obstruction of the LRV. The paucity of data regarding the management of this uncommon disease process poses a challenge for adequate recommendations of the best treatment modality. Herein, we aim to present a systematic review for the management of NS.
METHODS
We used the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement standards to systematically search the electronic databases of MEDLINE from October 1982 to July 2017 for articles about the management of NS. Included were studies in English, Spanish, and German in all age groups.
RESULTS
The literature search provided 249 references. After abstract and full review screening for inclusion, 17 references were analyzed. Eight (47%) described the open surgical approach. The LRV transposition was the most commonly reported technique, followed by renal autotransplantation. Seven (41.11%) described the endovascular technique of stent implantation, and two (11.7%) described the minimally invasive laparoscopic extravascular stent implantation.
CONCLUSIONS
NS is a rare entity. Multiple techniques have been developed for the treatment of this condition. However, the rarity of this syndrome, the paucity of data, and the short-term follow-up of the existing evidence are the disadvantages that prevent recommendations for the best treatment strategy. Up to now, open surgical intervention, specifically LRV transposition, has been considered by some experts the mainstay for treatment of NS. The endovascular approach is gaining strength as more evidence has become available. However, the long-term patency and durability of this approach remain to be elucidated. Therefore, careful selection of patients is necessary in recommending this technique.
Topics: Endovascular Procedures; Hemodynamics; Humans; Laparoscopy; Postoperative Complications; Renal Artery; Renal Circulation; Renal Nutcracker Syndrome; Stents; Time Factors; Treatment Outcome; Vascular Grafting; Vascular Patency
PubMed: 29292117
DOI: 10.1016/j.jvsv.2017.11.005 -
Current Opinion in Nephrology and... May 2015Over the past decade, a variety of MRI methods have been developed and applied to many kidney diseases. These MRI techniques show great promise, enabling the noninvasive... (Review)
Review
PURPOSE OF REVIEW
Over the past decade, a variety of MRI methods have been developed and applied to many kidney diseases. These MRI techniques show great promise, enabling the noninvasive assessment of renal structure, function and injury in individuals. This review will highlight the current applications of functional MRI techniques for the assessment of renal disease and discuss future directions.
RECENT FINDINGS
Many pathological (functional and structural) changes or factors in renal disease can be assessed by advanced MRI techniques. These include renal vascular structure and function (contrast-enhanced MRI, arterial spin labelling), tissue oxygenation (blood oxygen level dependent MRI), renal tissue injury and fibrosis (diffusion or magnetization transfer imaging, magnetic resonance elastography), renal metabolism (chemical exchange saturation transfer, spectroscopic imaging), nephron endowment (cationic-contrast imaging), sodium concentration (23Na-MRI) and molecular events (targeted-contrast imaging).
SUMMARY
Current advances in MRI techniques have enabled the noninvasive investigation of renal disease. Further development, evaluation and application of the MRI techniques should facilitate better understanding and assessment of renal disease, and the development of new imaging biomarkers, enabling the intensified treatment of high-risk populations and a more rapid interrogation of novel therapeutic agents and protocols.
Topics: Animals; Humans; Kidney; Kidney Diseases; Magnetic Resonance Imaging; Oxygen Consumption; Renal Circulation; Risk Assessment
PubMed: 26066472
DOI: 10.1097/MNH.0000000000000122 -
Physiological Reports Mar 2023The present study was to examine sex and strain differences in glomerular filtration rate (GFR) and renal blood flow (RBF) in C57BL6, 129/Sv, and C57BLKS/J mice, three...
The present study was to examine sex and strain differences in glomerular filtration rate (GFR) and renal blood flow (RBF) in C57BL6, 129/Sv, and C57BLKS/J mice, three commonly used mouse strains in renal research. GFR was measured by transdermal measurement of FITC-sinitrin clearance in conscious mice. RBF was measured by a flow probe placed in the renal artery under an anesthetic state. In C57BL6 mice, there were no sex differences in both GFR and RBF. In 129/Sv mice, females had significantly greater GFR than males at age of 24 weeks, but not at 8 weeks. However, males had higher RBF and lower renal vascular resistance (RVR). Similar to 129/Sv, female C57BLKS/J had significantly greater GFR at both 8 and 24 weeks, lower RBF, and higher RVR than males. Across strains, male 129/Sv had lower GFR and higher RBF than male C57BL6, but no significant difference in GFR and greater RBF than male C57BLKS/J. No significant difference in GFR or RBF was observed between C57BL6 and C57BLKS/J mice. Deletion of eNOS in C57BLKS/J mice reduced GFR in both sexes, but decreased RBF in males. Furthermore, there were no sex differences in the severity of renal injury in eNOS dbdb mice. Taken together, our study suggests that sex differences in renal hemodynamics in mice are strain and age dependent. eNOS was not involved in the sex differences in GFR, but in RBF. Furthermore, the sexual dimorphism did not impact the severity of renal injury in diabetic nephropathy.
Topics: Mice; Male; Animals; Female; Mice, Inbred C57BL; Kidney; Hemodynamics; Renal Circulation; Vascular Resistance; Glomerular Filtration Rate
PubMed: 36946063
DOI: 10.14814/phy2.15644 -
Hypertension (Dallas, Tex. : 1979) Feb 2020Impaired renal autoregulation permits more transmission of disturbance in systemic blood pressure, which initiates barotrauma in intrarenal microvasculatures such as...
Impaired renal autoregulation permits more transmission of disturbance in systemic blood pressure, which initiates barotrauma in intrarenal microvasculatures such as glomerular and tubulointerstitial capillaries, contributing to the development of kidney damage and deterioration in renal function, especially under the conditions with high blood pressure. Although it has been postulated that autoregulatory efficiency is attenuated in the aging kidney, direct evidence remains lacking. In the present study, we measured the autoregulation of renal blood flow, myogenic response of afferent arteriole (Af-Art), tubuloglomerular feedback in vivo with micropuncture, as well as tubuloglomerular feedback in vitro in isolated perfused juxtaglomerular apparatus in young and aged C57BL/6 mice. We found that renal blood flow was not significantly changed in response to a defined elevation of renal arterial pressure in young mice but significantly increased in aged mice. Additionally, myogenic response of Af-Art measured by microperfusion with a stepwise increase in perfusion pressure was significantly blunted in the aging kidney, which is associated with the attenuation of intraluminal pressure-induced intracellular calcium increases, as well as the reduced expression of integrin α5 (Itga5) in Af-Art. Moreover, both tubuloglomerular feedback in vivo and in vitro were nearly inactive in the aging kidney, which is associated with the significantly reduced expression of adenosine A1 receptor (A1AR) and suppressed vasoconstrictor response to adenosine in Af-Art. In conclusion, this study demonstrates that aging impairs renal autoregulation with blunted myogenic response and inhibited tubuloglomerular feedback response. The underlying mechanisms involve the downregulations of integrin α5 and A1AR in the Af-Art.
Topics: Aging; Animals; Blood Pressure; Disease Models, Animal; Glomerular Filtration Rate; Homeostasis; Hypertension; Kidney; Male; Mice; Mice, Inbred C57BL; Renal Circulation; Vasoconstriction
PubMed: 31838907
DOI: 10.1161/HYPERTENSIONAHA.119.13588 -
La Clinica Terapeutica 2020The aim of the present study was to demonstrate the relationship between hypertension stages according to JNC-8 classification and mean renal frame count (RFC), which is...
OBJECTIVE
The aim of the present study was to demonstrate the relationship between hypertension stages according to JNC-8 classification and mean renal frame count (RFC), which is an indicator of renal perfusion.
METHODS
In this retrospective study, 100 hypertensive patients without obstructive renal artery disease, who had been evaluated with renal artery angiography for hypertension, were allocated into 2 groups (Stage 1 and Stage 2 hypertension). During coronary angiography, the patients were evaluated by selective renal angiography using 6F Judkins catheter. Cineangiographic images were evaluated by the same clinician and mean RFC was estimated for both renal arteries. Injections during renal angiography were performed with power injector and same amount of radiopaque media with same speed was used for all patients.
RESULTS
There was no significant difference between the groups in terms of age, sex, duration of hypertension, and laboratory markers. Stage 2 hypertensive patients (Group 2) had a significantly higher mean RFC than Stage 1 hypertensive patients (Group 1) (p<0.001). The mean RFC of both kidneys in Group 2 was significantly higher than that of Group 1 (p<0.001 and p=0.023, respectively).
CONCLUSIONS
This study showed that the mean RFC increased with increases in hypertension levels and it could be used as an indicator of renal perfusion, which is an indirect marker of renal function. If renal artery flow gets slower, blood pressure levels increase and there is a proportional relationship between these two variables (mean RFC and blood pressure levels). This study also demonstrated that there was a statistically significant correlation between mean RFC and JNC-8 hypertension stages.
Topics: Aged; Contrast Media; Coronary Angiography; Female; Humans; Hypertension; Kidney; Kidney Function Tests; Male; Middle Aged; Renal Circulation; Retrospective Studies
PubMed: 32141485
DOI: 10.7417/CT.2020.2203 -
American Journal of Nephrology 2016Obesity is largely responsible for the growing incidence and prevalence of diabetes, cardiovascular and renal diseases. Current strategies to prevent and treat obesity... (Review)
Review
Obesity is largely responsible for the growing incidence and prevalence of diabetes, cardiovascular and renal diseases. Current strategies to prevent and treat obesity and its consequences have been insufficient to reverse the ongoing trends. Lifestyle modification or pharmacological therapies often produce modest weight loss which is not sustained and recurrence of obesity is frequently observed, leading to progression of target organ damage in many obese subjects. Therefore, research efforts have focused not only on the factors that regulate energy balance, but also on understanding mechanisms of target organ injury in obesity. Summary and Key Message: Microvascular (MV) disease plays a pivotal role in progressive kidney injury from different etiologies such as hypertension, diabetes, and atherosclerosis, which are all important consequences of chronic obesity. The MV networks are anatomical units that are closely adapted to specific functions of nutrition and removal of waste in every organ. Damage of the small vessels in several tissues and organs has been reported in obesity and may increase cardio-renal risk. However, the mechanisms by which obesity and its attendant cardiovascular and metabolic consequences interact to cause renal MV injury and chronic kidney disease are still unclear, although substantial progress has been made in recent years. This review addresses potential mechanisms and consequences of obesity-induced renal MV injury as well as current treatments that may provide protection of the renal microcirculation and slow progressive kidney injury in obesity.
Topics: Adipose Tissue; Animals; Humans; Inflammation; Microcirculation; Microvessels; Neovascularization, Pathologic; Obesity; Renal Circulation; Renal Insufficiency, Chronic
PubMed: 27771702
DOI: 10.1159/000452365 -
American Journal of Physiology.... Nov 2019Human studies of renal hemodynamics and metabolism in obesity are insufficient. We hypothesized that renal perfusion and renal free fatty acid (FFA) uptake are higher in...
Human studies of renal hemodynamics and metabolism in obesity are insufficient. We hypothesized that renal perfusion and renal free fatty acid (FFA) uptake are higher in subjects with morbid obesity compared with lean subjects and that they both decrease after bariatric surgery. Cortical and medullary hemodynamics and metabolism were measured in 23 morbidly obese women and 15 age- and sex-matched nonobese controls by PET scanning of [O]-HO (perfusion) and 14()-[F]fluoro-6-thia-heptadecanoate (FFA uptake). Kidney volume and radiodensity were measured by computed tomography, cardiac output by MRI. Obese subjects were re-studied 6 mo after bariatric surgery. Obese subjects had higher renal volume but lower radiodensity, suggesting accumulation of water and/or lipid. Both cardiac output and estimated glomerular filtration rate (eGFR) were increased by ~25% in the obese. Total renal blood flow was higher in the obese [885 (317) (expressed as median and interquartile range) vs. 749 (300) (expressed as means and SD) ml/min of controls, = 0.049]. In both groups, regional blood perfusion was higher in the cortex than medulla; in either region, FFA uptake was ~50% higher in the obese as a consequence of higher circulating FFA levels. Following weight loss (26 ± 8 kg), total renal blood flow was reduced ( = 0.006). Renal volume, eGFR, cortical and medullary FFA uptake were decreased but not fully normalized. Obesity is associated with renal structural, hemodynamic, and metabolic changes. Six months after bariatric surgery, the hemodynamic changes are reversed and the structural changes are improved. On the contrary, renal FFA uptake remains increased, driven by high substrate availability.
Topics: Adult; Bariatric Surgery; Fatty Acids; Female; Glomerular Filtration Rate; Hemodynamics; Humans; Kidney; Kidney Cortex; Kidney Medulla; Magnetic Resonance Imaging; Middle Aged; Obesity, Morbid; Renal Circulation; Tomography, X-Ray Computed; Weight Loss
PubMed: 31550182
DOI: 10.1152/ajpendo.00135.2019 -
Journal of Vascular Surgery Apr 2019Horseshoe kidney (HSK), referring to the abnormal fusion of the lower renal poles, represents one of the most common renal anomalies. One of its most significant... (Review)
Review
BACKGROUND
Horseshoe kidney (HSK), referring to the abnormal fusion of the lower renal poles, represents one of the most common renal anomalies. One of its most significant features is the anomalous vasculature, with a number of accessory renal arteries originating from the aorta, the mesenteric arteries, and even the iliac arteries supplying both the renal kidneys and the renal isthmus.
METHODS
A literature review was performed to identify and to present the most recent data regarding classification and imaging evaluation of HSK concomitant with abdominal aortic aneurysm (AAA). Furthermore, an in-depth analysis of both open surgical and endovascular repair is made for management of this rare medical condition.
RESULTS
The anomalous renal vasculature of HSK has led to the introduction of a number of classification systems, with Eisendrath's being currently the most commonly used. The concomitant presence of HSK in patients suffering from AAA plays a major role in preoperative planning, with a number of factors taken into consideration in deciding on either an open repair or an endovascular approach. Open repair requires careful decision-making between a transperitoneal and a left retroperitoneal approach to reach the aneurysm sac. In addition, technical points include the decision to divide the renal isthmus or not and the necessity of salvage or reimplantation of anomalous renal vessels. On the other hand, an endovascular approach requires careful preoperative imaging and evaluation of both the renal function and vasculature to decide on catheterization and salvage of accessory renal arteries or their exclusion.
CONCLUSIONS
The concomitant presence of AAA and HSK poses a challenge for the modern vascular surgeon, who must possess all required technical skills-both endovascular and open repair-to deal accordingly with this rarely encountered medical condition. Preoperative determination of the perfusion pattern is necessary for the treatment strategy.
Topics: Aortic Aneurysm, Abdominal; Blood Vessel Prosthesis Implantation; Endovascular Procedures; Fused Kidney; Humans; Renal Circulation; Risk Factors; Treatment Outcome
PubMed: 30591298
DOI: 10.1016/j.jvs.2018.10.009