Renal Artery Diameter Research Articles

E0658 Establishment of York pig model of acute myocardial infarction with acute decompensated heart failure by coronary occlusion with balloon and injecting of microembolus

ObjectiveTo evaluate the method of yorkpig model of AMI-ADHF by coronary occlusion with balloon and injecting of microembolus and evaluate the change of coronary and renal haemodynamic parameters on York...

E0656 The effect of recombinant human B-type natriuretic peptid on coronary circulation and renal haemodynamics in York pigs model of acute myocardial infarction with heart failure

ObjectiveTo evaluate the impact of intravenous administration of rhBNP on coronary and renal artery haemodynamics in York pigs model of AMI-ADHF.Methods14 York pigs were included in this study. After the...

E0626 The effects of recombinant human B-type natriuretic peptid on coronary circulation and renal haemodynamics in York pigs model of acute myocardial infarction with heart failure

ObjectiveTo evaluate the impact of intravenous administration of rhBNP on coronary and renal artery haemodynamics in York pigs model of AMI-ADHF.MethodsFourteen York pigs were included in this study. After the...

Comparative analysis of conventional ultrasonography and contrast-enhanced ultrasound in diagnosis of renal artery stenosis

Objective To compare contrast-enhanced ultrasound and conventional ultrasound in determining artery stenosis of varying degrees of accuracy. Methods Using conventional ultrasound and contrast-enhanced ultrasound renal artery stenosis was diagnosed.And the renal artery diameter stenosis were measured the extent to which digital subtraction angiography (DSA) as the standard diagnostic accuracy of two methods to determine the rate. Results 50 patients were diagnosed as renal artery stenosis with DSA,21 patients stenosis rate 30%-49%,23 patients stenosis rate 50%-75%,6 patients stenosis rate ＞75%.diagnose accordance rate 78%(38/50)with conventional color doppler and 92% (46/50) with contrast-enchanced ultrasound.The difference was statistically significant (P＜0.05＝. Conclusion Using ultrasound imaging of the renal artery stenosis to determine the degree had higher accuracy than the conventional ultrasonic testing method,was suitable for clinical application. Key words: Renal artery obstruction; Ultrasonography; Angiography

Can renal dimensions and the main renal artery diameter point to the presence of an accessory renal artery? a 64-slice CT study

To evaluate whether renal dimensions and the main renal artery (mRA) diameter can provide indirect evidence of the presence or absence of accessory renal arteries (aRA). The study group consisted of 167 patients (83 women, 84 men; mean age, 52.4±13.1 years) who presented to our radiology department for abdominal CT examinations with various indications. CT examination was performed on a 64-slice CT scanner in the arterial phase. The kidney diameters were recorded. The number of renal arteries supplying each kidney was evaluated, and their diameters were measured. We attempted to determine a formula that could be used to predict the presence or absence of aRAs. One or multiple aRAs were found in 76 (22.8%) of the 334 kidneys. The mRA diameter was 5.51±0.96 mm. The mRA diameter was smaller in kidneys with aRAs than in those without (P < 0.001). A cut-off value of 4.15 mm for the diameter of mRA to predict the presence of aRAs led to negative and positive predictive values of 80% and 90%, respectively. A formula that can predict that an aRA is absent with 97% accuracy given the values of the mRA diameter and the kidney length was determined using logistic regression. The mRA diameter (4.15 mm) alone and the results of the formula developed herein employing the mRA diameter and kidney length can respectively predict the presence or absence of an aRA with high accuracy.

Multidetector row computed tomography evaluation of the micropig kidney as a potential renal donor

Multidetector row computed tomography (MDCT) provides anatomical information about the kidney and other internal organs. Presently, the suitability of 64-channel MDCT to assess the kidney of healthy micropigs was evaluated. Morphological evaluations of the kidney and the major renal vessels of six healthy micropigs were carried out using MDCT, recording kidney volume and the diameter and length of renal arteries and veins. The mean diameters and lengths of the renal artery were 0.44 ± 0.05 and 4.51 ± 0.55 cm on the right side and 0.46 ± 0.06 and 3.36 ± 0.27 cm on the left side, respectively. The mean diameters and lengths of the renal vein were 1.44 ± 0.52 and 4.22 ± 1.29 cm on the right side and 1.38 ± 0.17 and 5.15 ± 0.87 cm on the left side, respectively. The mean volume of the right kidney was 79.3 ± 14.5 mL and of the left kidney was 78.0 ± 13.9 mL. The data presented in this study suggest that the MDCT offers a noninvasive, rapid, and accurate method for the evaluation of the renal anatomy in living kidney donors. It also provides sufficient information about extra-renal anatomy important for donor surgery and determination of organ suitability.

Anatomy character of renal artery and treatment of living-donor renal transplantation

To study the anatomy characters of renal artery and the treatment of multiple arteries in living donor renal grafts. Records of 142 living donors were analyzed in our center. We analyzed the anatomic structure of renal arteries by DSA and CTA pre-transplantation. Thirty-one kidneys with multiple arteries were transplanted after reconstruction. Then clinical effects were compared between multiple-renal-arteries group (n=31) and single-renal-artery group (n=111). The incidence of multiple renal artery was 30.99%, and there was no difference between both sides (left kidney 22.54%, right kidney 22.13%). If the multiple artery occurred in left or right kidney, the incidence of the multiple artery occurred in the other side was 56.25% and 60.00%, respectively. The diameter of left main renal artery was more magnanimous (P=0.001) and the first branch was more closed to abdominal aorta (P=0.004). Operation time and warm/cool ischemia time were longer in the multiple-renal-arteries group. However, estimated blood loss, delayed graft function, acute rejection and flow rate of arcuate artery were similar in both groups, the same as serum creatinine and serum creatinine clearance rate on day 7, 1 month and 3 month post-operation. It was shown by repeated measures ANOVA that graft with multiple arteries didn't affect the tendency of renal function at early time post-operation. Comprehending the character of renal artery and accurate treatment of multiple artery anastomosis are critical for the effect of the living kidney transplantation.

Origination Angle of Renal Artery Has No Role in Renal Artery Pattern

Renal artery (RA) anatomy plays a critical role in selecting donors. During the present study, we sought to evaluate the physiological role of RA origination angle for the presence of an accessory RA or its early branching. During the present cross-sectional study (August 2005-October 2007), 143 candidates for kidney donation underwent RA angiography by 64 multidetector computed tomographic angiography. We assessed the RA diameter, distance to first branching, presence of accessory RA, and early branching, as well as the origination angle of RA from aorta in coronal plane (alpha angle). The male-to-female ratio was 96:47 with an overall mean age of 27.42 +/- 4.55 years. The alpha angle, sine, cosine of the alpha angle and the deviation factor were not significantly different between kidneys with versus without an accessory artery or between the RA with versus without an early branching. Only the RA diameter (P = .047) and the distance of RA to the branching (P < .001) in kidneys with an accessory RA were significantly lower and higher than those without an accessory RA, respectively. Also the distance of the RA to the branching was significantly less in kidneys with an early branching (P < .001). The RA diameter directly correlated with the RA origination angle (r = .191, P = .001), while there was no correlation between the distance to RA branching and the RA origination angle (r = -.060, P = .311). The origination angle of the RA from aorta has no role in the early branching or accessory RA development. There was a direct correlation between the RA diameter and the RA origination angle.

Can Doppler Ultrasonographic Indices of the Renal Artery Predict the Presence of Supernumerary Renal Arteries?

Variations of the renal arteries, including the presence of supernumerary renal arteries, are important to be identified prior to renal transplant. Angiography has been the gold standard test for the pretransplant evaluation of the renal vasculature. However, this modality is expensive and invasive. The aim of this study was to assess whether Doppler ultrasonographic (DU) indices of the renal artery could predict the presence of supernumerary renal arteries. Retrospectively, we analyzed multidetector computed tomography angiography (presence or absence of the supernumerary renal artery), DU (peak systolic velocity, resistive index, pulsatility index, end-diastolic velocity, and acceleration time) findings of 30 healthy potential renal transplant donors. Recipient operator characteristic (ROC) curves were used to examine the predictive values of the available DU indices for supernumerary renal arteries. The mean age of donors was 28.4 +/- 4.1 years. Of 60 kidneys evaluated, a supernumerary renal artery was found in 10%. The ROC curve analysis revealed an area under the curve of noninformative (below 0.5) for all DU parameters, indicating that none of the studied parameters could predict the presence of a supernumerary renal artery. Although the smaller diameter of the main renal artery has previously been found to predict the presence of supernumerary renal arteries, the present study revealed that DU indices of the renal artery may not indicate the presence of supernumerary renal arteries.

Assessment of Renal Hemodynamic Effects of Nesiritide in Patients With Heart Failure Using Intravascular Doppler and Quantitative Angiography

We evaluated the magnitude and site of action of the nesiritide mediated renal vasodilatory effect in patients with heart failure (HF). Nesiritide, a recombinant human B-type natriuretic peptide is approved for the treatment of acute decompensated HF and has been shown to exert favorable hemodynamic, neurohormonal, and symptomatic effects. The renal effect of nesiritide in HF patients has not been well defined. In 15 patients with acute decompensated HF, intravascular Doppler and quantitative angiography of the renal artery were used to assess the effect of nesiritide on renal artery diameter and velocity time integral as well as renal blood flow and vascular resistance. Nesiritide was administered intravenously at a standard dose of 2 microg/kg bolus followed by a continuous infusion at a rate of 0.01 microg/kg/min. Assessment of nesiritide effect was made at 15 min. Nesiritide infusion was associated with a significant central hemodynamic effect including a fall in mean pulmonary artery pressure (36 +/- 12 mm Hg to 31 +/- 13 mm Hg, p < 0.001), mean pulmonary capillary wedge pressure (21 +/- 2 mm Hg to 15 +/- 10 mm Hg, p < 0.001), and systemic vascular resistance (1,995 +/- 532 dynes s cm(-5) to 1,563 +/- 504 dynes s cm(-5), r < 0.001), and an increase in cardiac output from 3.9 +/- 1.2 l/min to 4.6 +/- 1.6 l/min (p = 0.001). Nesiritide was also associated with a significant vasodilatory effect on the large conductance renal arteries resulting in an increase in renal artery diameter from 6.2 +/- 0.7 mm to 6.7 +/- 0.8 mm (p < 0.001). At the same time, there was a concomitant fall in mean renal artery pressure (99 +/- 17 mm Hg to 89 +/- 13 mm Hg, p = 0.002) and renal blood flow velocity time integral (27 +/- 15 cm/beat to 23 +/- 15 cm/beat, p = 0.008) and, therefore, no significant change in renal blood flow or renal vascular resistance. The nesiritide effect on the renal circulation in patients with HF is complex, with a marked vasodilatory action on the large, conductance renal arteries but a concomitant fall in velocity time integral and no effect on renal vascular resistance or renal blood flow. Lack of increase in renal blood flow may be due to a fall in renal blood pressure or an intrarenal vasoconstrictive effect.

Increased peak systolic velocity in the renal artery of paediatric kidneys transplanted to adult recipients

Paediatric kidneys transplanted to adult recipients increase in size after transplantation. It is unknown if the renal artery diameter increases concomitantly with the kidney. This study was performed to assess if peak systolic velocity (PSV) in the renal arteries of paediatric kidneys transplanted to adult recipients is comparable to PSV in the renal arteries of adult kidneys transplanted to adult recipients. Subjects and methods. Fifteen adult patients with paediatric renal transplants were examined with ultrasound Doppler and compared with a control group of adult recipients with adult transplants. MR angiography (MRA) or intra-arterial angiography (IA) was performed in patients with elevated PSV. MRA renal diameters of the paediatric transplants were compared with adult transplants. The mean maximum PSV of the paediatric kidneys was 2.0 m/s (0.9-3.8), almost twice compared with the adult grafts transplanted to adult recipients, 1.1 m/s (0.7-1.6), P < 0.001. Seven paediatric transplants had a PSV >1.8 m/s, but only two had significant stenosis on MRA/IA. All patients had excellent blood pressure and renal function. The mean diameter of the paediatric renal arteries was 4.1 mm (3.4-6.0), whereas the mean for the adult renal arteries was 5.6 mm (4.8-6.9), P = 0.02. Adult recipients of paediatric kidneys have significantly higher maximum PSV in the renal artery compared to adult recipients of adult grafts. The significantly smaller renal artery diameter might explain the high PSV. A PSV >1.8 m/s by itself does not necessarily indicate transplant renal artery stenosis in paediatric kidneys transplanted to adult recipients, but should be related to clinical findings.

Do Mechanical Fluid Laws Dictate the Branching Pattern of the Renal Artery?

Introduction Anatomy of the renal artery is an important issue in the renal transplantation era. Multi-detector computed tomography angiography (MDCTA) is an accurate modality for the preoperative assessment of live renal donors, and it provides excellent details of donor arterial anatomy. We studied the relationship between the angle of emergence of the renal artery from the aorta and its branching pattern. Methods In this study, the MDCTA images obtained from the 138 kidneys of 77 potential renal transplant donors were studied. The courses of the right and left renal arteries from the aorta to the kidney hilus were delineated. The branching angle of the renal artery from the aorta (β, angle) and the length of the renal artery from the aorta until its first division were measured (Δ, distance). The renal artery deviation from the perpendicular plane of the aorta (D, factor of deviation) was calculated by the following formula: D = (1 − sin [β]). The cosine of this angle (cos [β]) was also calculated. Statistical analyses were performed with Pearson correlation tests. The P value was set at .05. Results The mean age of patients was 28.7 +/− 4.3 with a male to female ratio of 63:14. The mean Δ distance and д diameter were 34.37 +/− 10.68 mm (range, 10–58) and 6.13 +/− 1.37 mm (range, 2.8–9.9), respectively. The mean β angle, factor of deviation, and cos (β) were 62.19° +/− 16.44, 0.15 +/− 0.14, and 0.45 +/− 0.25, respectively. Significant negative correlations were found between the β angle, and Δ distance ( r = −0.308; P < .001), and д diameter ( r = −0.303; P = .003). Factor of deviation and cos (β) were directly associated Δ distance and д diameter. Conclusion These findings indicated that with the main renal artery axis deviating from the perpendicular plane of the aorta or with a smaller branching angle, this artery had a greater diameter and underwent late branching. This study suggested that the renal artery diameter and branching pattern might be determined by the mechanical fluid laws.

Atheroembolism during percutaneous renal artery revascularization

Atheroembolization during renal artery angioplasty and stenting (RA-PTAS) has been postulated as a cause for the inferior renal function results observed when compared with those with surgical revascularization. To further characterize procedure-associated atheroembolism, we analyzed recovered atheroembolic debris and clinical data from patients undergoing RA-PTAS with distal embolic protection (DEP). RA-PTAS procedures were performed with DEP using a commercially available temporary balloon occlusion and aspiration catheter system between July 2005 and December 2006. Following RA-PTAS but prior to deflation of the distal occlusion balloon, the static column of blood proximal to the balloon was aspirated and submitted for embolic particle analysis. Angiograms, demographics, and laboratory data were reviewed. Glomerular filtration rate (eGFR) was estimated before RA-PTAS and at 4 to 8 weeks postintervention using the abbreviated Modification of Diet in Renal Disease formula. Associations between clinical factors, captured particle counts, and changes in renal function were examined using univariate techniques and multiple linear regression. Twenty-eight RA-PTAS procedures were performed with DEP. Mean total number of embolic particles counted per procedure was 2033 +/- 1553 for particles 20-60 microm and 265 +/- 132 for particles >60 microm. Significant positive associations with quantity of captured particles 20 to 60 microm were observed for African American race (P = .002), predilation (P = .005), and stent diameter (P < .001); a significant negative association was observed for preoperative aspirin use (P =.016). Quantity of captured particles >60 microm was positively associated with ratio of stent to renal artery diameter (P =.009). Change in eGFR was positively associated with preoperative aspirin use (P = .006) and preoperative eGFR (P < .001), while a negative association was observed for captured particle counts >60 microm (P = .015). These results demonstrate the liberation of thousands of atheroembolic particles during RA-PTAS. Clinical, anatomic, and device-related factors may be predictive of procedural embolization, and increasing captured particle counts >60 microm were associated with inferior renal function results. Further investigation is warranted to establish relationships between atheroembolism, end organ functional impairment, and clinical responses.

CT Angiography of Renal Artery Anatomy for Evaluating Embolic Protection Devices

To determine which commercially available embolic protection devices are suitable for use in renal arteries. A retrospective study was conducted of 97 patients who underwent three-dimensional computed tomographic (CT) angiography with either 16- or 64-detector row helical CT of the renal arteries for the evaluation of renal artery stenosis. Nine anatomic measurements were obtained of the renal artery from each reformatted CT angiogram. These data were used to evaluate seven commercially available embolic protection devices (SpideRX, BSC FilterWire EZ, GuardWire, Angioguard, Accunet, Emboshield, TriActiv FX) to determine suitability for use in conjunction with renal artery stent placement. The authors evaluated the reference vessel diameter (diameter to which the stent would be expanded) and length of device. The mean length (+/- standard deviation) of the main renal artery on the left (39.9 mm +/- 6.7) was significantly less than that on the right (44.9 mm +/- 7.4, P < .001). The mean distal diameter of the main renal artery was significantly larger on the left (6.0 mm +/- 0.5) than on the right (5.6 mm +/- 0.6, P = .02). For a reference vessel diameter of 4-7 mm necessitating a 12-mm-long stent, only three of the seven devices tested (SpideRx, Angioguard, and Accunet) could be used. Three of the seven devices tested could be used for reference vessel diameters of 4-7 mm necessitating a 12-mm-long stent.

Diagnosis and Management of Ischemic Nephropathy

Analysis of the Third National Health and Nutrition Examination Survey (1988 to 1994) suggests that chronic kidney disease (CKD) is a major public health problem (1). Approximately 11% of the US population has CKD. Roughly half have a GFR <60 ml/min per 1.73 m2 with or without kidney damage (stages 3 to 4), and half have exclusively kidney damage as manifested by microalbuminuria (stages 1 to 2) (2). It is widely recognized that the prevalence of stage 5 CKD is also increasing at a rapid rate, and it is estimated that the number of patients who have ESRD may reach 2.24 million by 2030 (3). Evidence to establish reduced GFR as an independent risk factor for cardiovascular disease (CVD) mortality has emerged. Analysis of data from several population-based epidemiologic studies (4,5) demonstrates poorer outcomes regarding stroke, myocardial infarction, and congestive heart failure (CHF) in patients with even mild compromise of kidney function. The morbidity of this group of patients constitutes an economic burden both directly in terms of resource utilization and indirectly through loss of productivity and impaired quality of life (2). Atherosclerotic renovascular disease (ARVD) can result in renovascular hypertension. However, ARVD is an increasingly recognized cause of CKD (6,7). In this article, we focus mainly on ARVD or renal artery stenosis (RAS) secondary to atherosclerosis as a cause of ischemic nephropathy. ARVD is a disease of aging, and several studies have shown its strong association with extrarenal atherosclerotic disease (8–10). Patients with ARVD seem to be at a much greater risk for cardiovascular death than for progressing to renal replacement therapy (11). Whether renal revascularization can benefit renal and cardiovascular outcomes has not been established. Atherosclerosis is the cause of approximately 90% of RAS in adults who are older …

Giant renal artery aneurysm

A hypertensive 67-year-old woman was admitted with a large, non-tender abdominal mass that caused a gross bulging of the abdominal wall. The patient was symptom-free except for occasional low back pain. She had been aware of the mass for over 5 years, but had not sought medical attention. Her family history was negative for significant vascular pathology. She had no history of trauma or instrumentation. Renal function was normal. Computed tomography scan (Cover) showed a giant aneurysm of the left renal artery (diameter 25 cm). The wall was calcified; thrombosis was extensive, but incomplete and dyshomogenous. The abdominal organs were dislodged to the right. No other aneurysmal locations were disclosed. Magnetic resonance angiography (A) showed the origin of the lumen of the aneurysm to be in the mid-left renal artery. Surgery was performed through a transverse laparotomy. The gastrocolic ligament was incised and the anterior wall of the aneurysm exposed and incised (B). The thrombus was removed from the sac and the origin of the aneurysm from the left renal artery exposed (C, arrow). A breach in the arterial wall was visible. The unclamped artery was digitally compressed for hemostasis while the artery was closed primarily. Pathologic examination confirmed a true atherosclerotic aneurysm. The patient is alive and well 6 months after the operation, with normal renal function. Aneurysms of the renal artery may occasionally reach large dimensions, but this case must be considered exceptional. It is actually extremely uncommon for aneurysms in any location to reach this size without rupturing. Giant renal artery aneurysms ( 5 cm. diameter) have been reported in fewer than 20 cases in the English literature. They may be pseudoaneurysms, usually secondary to invasive procedures such as percutaneous transluminal angioplasty or pyelolithotomy, or true aneurysms, often with parietal calcifications. The principal justifications for surgical treatment are ureteral obstruction, hypertension, pain, and elimination of the risk for rupture. Repair may require arterial reconstruction or even nephrectomy, but may also require only simple closure of the artery defect, as was possible here.

Effects of intravenous nesiritide on renal hemodynamics in patients with congestive heart failure

Objectives: To evaluate the renal circulatory effects of intravenous nesiritide in patients with congestive heart failure (CHF). Background: Nesiritide, recombinant human B-type natriuretic peptide, has been shown to be efficacious in the treatment of decompensated heart failure and to improve renal function. The exact mechanism of nesiritide effect on the kidney and renal circulation in patients with CHF has not been fully investigated. Methods: Thirteen patients with CHF underwent cardiac catheterization and measurements of renal blood flow using quantitative renal artery angiography and intra renal arterial Doppler flow velocity at baseline, after nesiritide bolus injection (2μ/kg) and 15 minutes after initiation of continuous nesiritide infusion (0.01μ/kg/min). Results: Fifteen minutes of continuous nesiritide infusion resulted in 13% reduction in mean right atrial pressure (p=0.16), 15% in mean pulmonary artery pressure (p<0.005) and 30% in mean pulmonary capillary wedge pressure (p<0.005). Changes in renal hemodynamics were as follows: (please see table). Conclusions: Nesiritide exerts a renal vasodilatory effect predominantly on the large conductance vessels. Renal blood flow is increased after bolus nesiritide administration and is maintained during nesiritide continous infusion in spite of a significant decrease in renal perfusion pressure.∗Changes in renal hemodynamics post nesiritide bolus and during a 15 minutes nesiritide infusion compared to baselineMean Renal Artery Pressure (mmHg)Renal Artery Diameter (mm)Average Renal Peak Velocity (m/s)Renal Blood Flow (ml/min)Baseline99±176.24±0.729±16269±164Bolus93±156.36±0.832±18316±213∗Infusion89±12∗6.73±0.8∗∗24±16∗262±189†∗p<0.05 vs baseline∗∗p<0.0005 vs baseline†p=0.02 vs bolus

Prevalence of atherosclerotic renal artery stenosis in patients starting dialysis.

Atherosclerotic renal artery stenosis (ARAS) can lead to end-stage renal failure (ESRF). We determined the prevalence of ARAS in patients 45 years of age or older starting renal replacement therapy. Forty-nine of 80 consecutive patients (37 males, 12 females) starting renal replacement therapy in our centre gave informed consent and underwent spiral computed tomographic angiography of their renal arteries. A renal artery diameter reduction of 50% or more assessed by two radiologists was considered as a significant stenosis. Twenty of 49 patients (41%) had an ARAS, and in eight cases (16%) this was bilateral or unilateral with a single kidney. Women were more likely to have an ARAS than men; 75 (9/12) vs 30% (11/37, P<0.01). However, relatively more women declined participation. Non-participants and participants did not differ in respect to other relevant clinical data. Nonetheless, findings in these patients would be negative, the prevalence of ARAS would still be 31% in women and 22% in men (NS). In 13 patients with ARAS the registered diagnosis of ESRF either was hypertension, renovascular disease or unknown. Assuming that in these patients atherosclerotic renovascular disease was the cause of renal failure, a total of 13 patients (13/49, 27%) entered the dialysis programme because of this problem. These results suggest that ARAS is an important cause of ESRF.

Role of 20-hydroxyeicosatetraenoic acid in the renal and vasoconstrictor actions of angiotensin II

The present study examined the effects of ANG II on the renal synthesis of 20-hydroxyeicosatetraenoic acid (20-HETE) and its contribution to the renal vasoconstrictor and the acute and chronic pressor effects of ANG II in rats. ANG II (10(-11) to 10(-7) mol/l) reduced the diameter of renal interlobular arteries treated with inhibitors of nitric oxide synthase and cyclooxygenase, lipoxygenase, and epoxygenase by 81 +/- 8%. Subsequent blockade of the synthesis of 20-HETE with 17-octadecynoic acid (1 micromol/l) increased the ED(50) for ANG II-induced constriction by a factor of 15 and diminished the maximal response by 61%. Graded intravenous infusion of ANG II (5-200 ng/min) dose dependently increased mean arterial pressure (MAP) in thiobutylbarbitol-anesthetized rats by 35 mmHg. Acute blockade of the formation of 20-HETE with dibromododecenyl methylsulfimide (DDMS; 10 mg/kg) attenuated the pressor response to ANG II by 40%. An intravenous infusion of ANG II (50 ng. kg(-1). min(-1)) in rats for 5 days increased the formation of 20-HETE and epoxyeicosatrienoic acids (EETs) in renal cortical microsomes by 60 and 400%, respectively, and increased MAP by 78 mmHg. Chronic blockade of the synthesis of 20-HETE with intravenous infusion of DDMS (1 mg. kg(-1). h(-1)) or EETs and 20-HETE with 1-aminobenzotriazole (ABT; 2.2 mg. kg(-1). h(-1)) attenuated the ANG II-induced rise in MAP by 40%. Control urinary excretion of 20-HETE averaged 350 +/- 23 ng/day and increased to 1,020 +/- 105 ng/day in rats infused with ANG II (50 ng. kg(-1). min(-1)) for 5 days. In contrast, urinary excretion of 20-HETE only rose to 400 +/- 40 and 600 +/- 25 ng/day in rats chronically treated with ANG II and ABT or DDMS respectively. These results suggest that acute and chronic elevations in circulating ANG II levels increase the formation of 20-HETE in the kidney and peripheral vasculature and that 20-HETE contributes to the acute and chronic pressor effects of ANG II.

Shrinkage of the distal renal artery 1 year after stent placement as evidenced with serial intravascular ultrasound.

The objective of this study was to determine the quantitative intravascular ultrasound (IVUS) and angiographic changes that occur during 1 year follow-up after renal artery stent placement, given that restenosis continues to be a limitation of renal artery stent placement. 38 consecutive patients with symptomatic renal artery stenosis treated with Palmaz stent placement were studied prospectively. IVUS and angiography were performed at the time of stent placement and at 1 year follow-up. At follow-up, angiographic restenosis was seen in 14% of patients. The lumen area in the stent, seen with IVUS, was significantly decreased from 24+/-5.6 mm(2) to 17+/-5.6 mm(2) (p<0.001) solely due to plaque accumulation. The distal main renal artery showed a significant decrease in lumen area owing to a significant vessel area decrease from 39+/-14.0 mm(2) to 29+/-9.3 mm(2) (p<0.001) without plaque accumulation. Angiographic analysis confirmed this reduction in luminal diameter and showed that the distal renal artery diameter at follow-up was significantly smaller than before stent placement (86+/-23.0% vs 104+/-23.9% of the contralateral renal artery diameter; p=0.003). Besides plaque accumulation in the stent, unexplained shrinkage of the distal main renal artery was evidenced with IVUS and angiography 1 year following stent placement.