Predictors of embolization during protected renal artery angioplasty and stenting: Role of antiplatelet therapy

Objective: The objective of this study was to identify the predictors of distal embolization (DE) during protected renal artery angioplasty and stenting. Background: DE may contribute to worsening renal function after renal artery stenting. The factors associated with DE, rates of platelet‐rich emboli, and treatments that may prevent DE during renal stenting have not been evaluated. Methods: The current study evaluated patients randomized to receive an embolic protection device (EPD) in the RESIST trial. Forty‐two patients were identified for inclusion in this study. These patients were further randomized to abcizimab (N = 22) or placebo (N = 20). Modification in Diet in Renal Disease glomerular filtration rate (GFR) was used as the primary measure of renal function. Creatinine was measured by a modified Jaffe reaction using the IDMS‐traceable assay. The primary endpoint was capture of platelet rich emboli in the angioguard basket. Results: DE occurred in 15/42 (35%) of the patients and platelet rich DE in 10 (24%) of the patients who received an EPD. Of the angiographic characteristics only lesion length was significantly higher in patients with DE (16 ± 7 mm vs. 10 ± 5 mm, P = 0.04). Preprocedural abciximab reduced DE from 42 to 8% (P = 0.02). The rate of platelet rich emboli was 50% with neither abciximab nor a thienopyridine, 36% with thienopyridine only, 15% abciximab only, and 0% in patients who received both a thienopyridine and abciximab. Only Abciximab use was associated with improved renal function at 1‐month, thienopyridine was not. Angiographic characteristics including percent stenosis, minimal luminal diameter (MLD), reference diameter, change in MLD, contrast volume, and procedure time were not predictors of DE during renal stenting. Conclusion: Capture of DE and specifically platelet DE are common during protected renal stenting using a filter‐type EPD. Abciximab use, and potentially combined thienopyridine and abciximab use, decreased the rate of platelet rich DE; however, only abciximab improved renal function at 1‐month. © 2010 Wiley‐Liss, Inc.     

Prospective evaluation of aggressive medical therapy for atherosclerotic renal artery stenosis, with renal artery stenting reserved for previously injured heart, brain, or kidney

Sixty-six patients with atherosclerotic renal artery stenosis (RAS) and serum creatinine < or =2.0 mg/dl were treated with antihypertensive therapy, a statin, and aspirin. Renal stenting was reserved for patients with injuries to the heart, brain, or kidneys. The primary end point was stenotic kidney glomerular filtration rate (GFR) at 21 months; secondary end points included major adverse clinical events, serum creatinine, total GFR, and blood pressure (BP). After baseline evaluation, 26 of 66 patients underwent renal stenting because of injuries to the heart, brain, or kidneys. After 21 months, 6 medical patients required renal stenting, and 5 patients experienced late clinical events (2 medical patients, 3 stent patients). There was no difference in final BP between groups. Whereas medical patients experienced 6% and 8% decreases in total and stenotic kidney GFR, stent patients experienced 7% and 11% increases in total kidney (p = 0.006) and stenotic kidney (p = 0.02) GFR. There was no difference in final serum creatinine. In conclusion, patients with atherosclerotic RAS and baseline creatinine < or =2.0 mg/dl can be safely managed with aggressive medical therapy, with a small decrease in GFR. For patients who develop injuries to the heart, brain, or kidneys, renal artery stenting may further reduce hypertension and improve renal function.     

Usefulness of translesional pressure gradient and pharmacological provocation for the assessment of intermediate renal artery disease.

OBJECTIVE: We sought to determine the hemodynamic significance of intermediate RAS by measuring translesional systolic pressure gradients (TSPG), using a pressure-sensing guidewire at baseline and after acetylcholine (ACh) induced hyperemia, following selective renal artery angiography. BACKGROUND: Renal artery stenosis (RAS) is a cause of reversible hypertension and nephropathy. Stenting effectively relieves RAS, however improvement in blood pressure control or renal function is variable and unpredictable. Hemodynamic significance is usually present with RAS when diameter stenosis is >75%, but is less predictable in intermediate (30%-75%) RAS. METHODS: Twenty-two patients (26 renal arteries) with uncontrolled hypertension underwent invasive hemodynamic assessment because of intermediate RAS, defined as radiocontrast angiographic diameter stenosis (DS) between 30% and 75% (quantitative DS was measured prospectively). Translesional pressure gradients were measured using a 0.014" pressure-sensing wire. Hyperemia was induced by administration of intrarenal ACh. RESULTS: Visual and measured angiographic lesion severity did not correlate with TSPG either at baseline (visual DS, R(2) = 0.091, P = 0.13; measured DS, R(2) = 0.124, P = 0.07) or with hyperemia (visual DS, R(2) = 0.057, P = 0.24; measured DS, R(2) = 0.101, P = 0.12). Baseline and maximal hyperemic gradient did correlate (R(2) = 0.567; P < 0.05). Pharmacological provocation produced a significant increase in TSPG (mean; baseline, 18 +/- 21 vs. hyperemia, 34 +/- 41 mm Hg; P < 0.05). A hemodynamically significant lesion (TSPG > 20 mm Hg) was found in 14/26 (54%) arteries (13 patients); 13 (60%) patients subsequently underwent renal artery stenting for hemodynamically significant RAS. At follow-up (at least 30 days), there was a significant decrease in systolic blood pressure (mean; 167 +/- 24 vs. 134 +/- 19 mm Hg; P < 0.001). CONCLUSIONS: Intrarenal administration of ACh induces hyperemia and can be used to unmask resistive renal artery lesions. Gradient measurement and induced hyperemia may be warranted in the invasive assessment of intermediate renal artery stenoses, rather than relying on stenosis severity alone. Further study is needed to determine whether translesional pressure gradients and pharmacological provocation predict clinical benefit after renal artery stenting.     

Assessment of renal artery stenosis using both resting pressures ratio and fractional flow reserve: relationship to angiography and ultrasonography

BACKGROUND. Clinical benefit from renal artery revascularization remains controversial, probably because of inaccurate stenosis severity assessment. Objective. The aim of the study was to evaluate resting translesional pressures ratio and renal fractional flow reserve (rFFR) in relation to angiography and Doppler duplex ultrasonography in patients with at least moderate renal artery stenosis (RAS). METHODS. 44 hypertensive patients (48% of males, mean age 65 years) with at least moderate RAS were investigated. Translesional systolic pressure gradient (TSPG), resting Pd/Pa ratio (the ratio of mean distal to lesion and mean proximal pressures) and hyperemic rFFR - after intrarenal administration of papaverine - were evaluated. Quantitative angiographic analysis of stenosis severity was performed including minimal lumen diameter (MLD) and percent diameter stenosis (DS) assessment. Renal/aortic ratio (RAR), resistive index (RI) and deltaRI (side-to side difference) were obtained in Doppler-duplex ultrasonography. The predictive value of selected variables was calculated using receiver-operating characteristics curves. RESULTS. Mean Pd/Pa ratio was 0.86 ± 0.12 and decreased to 0.79 ± 0.13 after papaverine administration. Both Pd/Pa ratio and rFFR strongly correlated with TSPG (r = -0.92, p < 0.0001 and r = -0.88, p < 0.0001, respectively) and moderately with MLD (r = 0.62, p < 0.0001 and r = 0.66, p < 0.0001) and DS (r = -0.63, p < 0.0001 and r = -0.70, p < 0.0001). To identify more than 70% RAS, considered severe, the most predictive cut-off values were 0.93 for Pd/Pa ratio and 0.80 for rFFR. CONCLUSIONS. Mean Pd/Pa ratio and rFFR strongly correlated with angiographic data and in less pronounced manner with ultrasound parameters reflecting intrarenal blood flow. The best accuracy cut-off points for severe RAS predicting were 0.93 and 0.80, respectively.     

Renal artery stenting using gadodiamide arteriography in patients with baseline renal insufficiency.

PURPOSE: To investigate whether a contrast agent containing gadodiamide can reduce the incidence of contrast-induced nephropathy associated with renal artery stenting in patients with preexisting renal insufficiency. METHODS: Between 1999 and 2002, gadodiamide-based arteriography was used in 20 patients (12 men; mean age 69 years) with significant baseline renal insufficiency (creatinine > or =1.7 mg/dL) undergoing renal artery stenting for > or =70% stenoses in 25 renal arteries. Baseline creatinine levels were compared to postprocedure and midterm follow-up levels.Results: Procedural success was 100%. An average of 74 mL of gadodiamide contrast was used per case. Four patients received an additional 30 mL (mean) of iodinated contrast due to poor image quality with gadodiamide alone. There was no significant change in mean creatinine levels at discharge (2.9 mg/dL) compared to baseline (3.0 mg/dL, p=0.72). At midterm follow-up, mean creatinine levels (2.4 mg/dL) were significantly lower compared to baseline (p=0.004). CONCLUSIONS: Gadodiamide-based arteriography can be effectively used during RAS in patients with baseline renal insufficiency. This technique may enhance the renal-protective effect of renal artery stenting in this high-risk population with renal artery stenosis.     

Serum cystatin C versus serum creatinine in the estimation of glomerular filtration rate in rhabdomyolysis

Cystatin C has emerged as a possible, usable surrogate marker of renal function. We present a case that illustrates the clinical utility of cystatin C in the setting of acute kidney injury secondary to rhabdomyolysis. An African American male whose baseline cystatin C and serum creatinine levels taken a month prior to admission were compared against their daily values during his admission and at follow up. On admission, the patient's reduction in glomerular filtration rate (GFR) from baseline was much less when calculated with cystatin C than with serum creatinine. His clinical recovery was more reflective of the higher GFR with cystatin C than what would be assumed with his serum creatinine, which at its worst was 5 ml/min/1.73 m(2). The patient was eventually discharged from the hospital with a GFR of 40 ml/min by cystatin C despite his GFR by the MDRD equation being 12. Cystatin C may be a more accurate marker of the both the amount of injury and the rate of resolution of acute kidney injury than serum creatinine in rhabdomyolysis.     

Serum cystatin C concentration compared with other markers of glomerular filtration rate in the old old

OBJECTIVES: To assess serum cystatin C, compared with other markers of renal function, as a marker of renal function in the old old (aged 85 and older). DESIGN: A cross-sectional analysis of data obtained in medically stable people aged 70 and older in a geriatric ward at a university hospital. SETTING: University hospital in Belgium. PARTICIPANTS: Forty-eight patients (17 men, 31 women) mean age +/- standard deviation 84.4 +/- 6.3 without acute illness or overt malignancy 7 days after admission were included. Twenty-five patients were aged 85 and older. MEASUREMENTS: Blood samples and 24-hour urine collections were obtained from each patient to determine serum creatinine, serum cystatin C levels, serum albumin, and creatinine clearance. Glomerular filtration rate (GFR) was estimated using the Cockcroft-Gault formula and the Modification of Diet in Renal Study Group (MDRD) formula. On the same day, clearance of 51chromium ethylenediamine tetraacetic acid was performed in all patients as the criterion standard of GFR. RESULTS: Serum creatinine (r=0.68), serum cystatin C (r=0.62), urinary creatinine clearance (r=0.57), the Cockcroft-Gault formula (r=0.82), and the MDRD-formula (r=0.65) correlated significantly with GFR (P <.0001). Regression analysis showed that serum cystatin C and serum creatinine were comparable markers of renal function (Y=0.442 +/- 0.007 x GFR and Y=0.494 +/- 0.01 x GFR respectively). Receiver operating characteristic analysis showed a similar area under the curve for serum cystatin C and serum creatinine (P=.5) in detecting renal impairment (GFR <80 mL/min). The Cockcroft-Gault formula provides a good estimation of GFR when the GFR is less than 60 mL/min (Y=1.11 +/- 1.04 x GFR). When the GFR is greater than 60 mL/min, the Cockcroft-Gault formula underestimates GFR (Y=11.01 +/- 0.66 x GFR). In patients aged 85 and older, a slight decrease in GFR (51.8 +/- 21.3 mL/min vs 65.2 +/- 34.3 mL/min in patients aged 70-84; P=.10) is observed. This is reflected by a nonsignificant increase in serum cystatin C (P=.06), whereas serum creatinine is identical in both groups (P=.88). CONCLUSION: Serum cystatin C, serum creatinine, the Cockcroft-Gault formula, the MDRD formula, and urinary creatinine clearance are comparable markers of renal function in the overall older population. The Cockcroft-Gault formula underestimates renal function in older people with GFR greater than 60 mL/min. In our study, serum cystatin C was not superior to serum creatinine in the detection of renal impairment.     

Estimation of the glomerular filtration rate in elderly inpatients: comparison of four methods

PURPOSE: High variability has been observed in the estimation of the glomerular filtration rate (GFR) in older patients, according to the formula used and no single formula has been recommended to date. The aim of this study was to quantify the precision and accuracy of the GFR estimated by means of three formulas and the measurement of cystatin C. METHODS: This prospective study was conducted in an acute care geriatric unit. Participants were patients, aged 70 years and over, having a possible 24-hour urine collection. The GFR was estimated using the Cockroft-Gault (CG), the Modification of Diet in Renal Disease (MDRD), and the Creatinine Clearance (Cl-Cr) formulas. The serum level of cystatin C was also measured. RESULTS: Eighty-one patients were included in the study. CG formula underestimated the GFR by a mean difference of 8.65 ml/min, compared with MDRD formula. Cl-Cr underestimated the GFR by a mean difference of 7.56 ml/min, compared with CG formula, and by a mean difference of 16.79 ml/min, compared with the MDRD formula. The degree of discrepancy between CG and Cl-Cr estimates, and between Cl-Cr and MDRD estimates decreased as the estimated GFR approached normal values. MDRD best matched the measurement of cystatin C, followed by CG and Cl-Cr (Kappa coefficient=0.43, 0.22 and 0.16, respectively). CONCLUSION: Our study confirms the high variability of GFR in older patients and particularly in those with abnormal renal function, depending on the formula used. Serum cystatine C level and MDRD formula appear to be the most concordant estimates of GFR in this population.     

Assessment of renal artery stenosis: side-by-side comparison of angiography and duplex ultrasound with pressure gradient measurements.

AIMS: A ratio of distal renal pressure to aortic pressure (P(d)/P(a)) <0.90 can be considered a threshold for defining a significant renal artery stenosis (RAS). The aim of this study was to compare renal angiography (QRA) and colour duplex ultrasound (CDUS) to pressure measurements in assessing RAS. METHODS AND RESULTS: In 56 RAS, percent diameter stenosis (DS(angio)), minimal luminal diameter (MLD), Doppler-derived peak systolic velocity (PSV), end-diastolic velocity (EDV), and renal-to-aortic ratio (RAR) were obtained and compared with the P(d)/P(a) measured with a 0.014" pressure wire. P(d)/P(a) correlated with angiography- and CDUS-derived parameters. The best correlation was observed with EDV (R = -0.61). To identify stenosis associated with a P(d)/P(a) < 0.90, the diagnostic accuracy of DS(angio) > 50%, MLD < 2 mm, PSV > 180 cm/s, EDV > 90 cm/s and RAR > 3.5 were, respectively, 60%, 77%, 45%, 77% and 79%, yet, with a high proportion of false positives (38%, 15%, 55%, 11% and 15%, respectively) indicating an overestimation of the severity of the RAS by both QRA and CDUS. New cut-off values for QRA- and CDUS-derived indices were proposed. CONCLUSION: Generally accepted QRA and CDUS-derived indices of RAS severity overestimate the actual severity of RAS. This 'overdiagnosis' is likely the main cause of the disappointing results of renal angioplasty for renovascular hypertension.     

Accuracy of indirect estimates of renal function in advanced chronic renal failure patients

Cockcroft-Gault (CG) and Modification of Diet in Renal Disease (MDRD) formula are indirect estimates of renal function which have been widely accepted, though their accuracies have been scarcely validated in advanced chronic renal failure. The purpose of this study was to determine the accuracy (bias and precision) of these formulas in advanced CRF patients. The study group consisted of 99 unselected patients (62 +/- 15 years, 59 females) with advanced CRF. The glomerular filtration rate (GFR) was measured by Tc(99m) DTPA. Simultaneously, estimates of GFR by CG corrected for 1.73 m2 and MDRD (formula 7) were calculated. Agreement was evaluated graphically, bias was assessed by mean and median difference, and precision by median absolute differences and Bland-Altman plots. Mean GFR by DTPA, CG and MDRD were: 16.24 +/- 4.38 and 16.77 +/- 4.65 and 13.58 +/- 4.27 ml/min/1.73 m2, respectively. MDRD equation significantly underestimated GFR-DTPA (p = 0.0001). Both CG and MDRD correlated significantly with GFR-DTPA (R = 0.53 and R = 0.62, respectively). CG formula performed better than the MDRD equation with respect to bias (0.30 vs -3.24 ml/min/1.73 m2, p = 0.0001), and precision (0.58 vs. -3.11 ml/min/1.73 m2, p = 0.0001). By multiple linear regression, the best determinants of the error of the estimation by CC formula were: serum creatinine (beta = -0.58; p < 0.0001), age (beta = -0.62; p < 0.0001), and body mass index (beta = 0.26, p = 0.004), and by MDRD formula were: serum creatinine (beta = -0.38; p < 0.0001), and body mass index (beta = -0.20, p = 0.03). In conclusion, in unselected patients with advanced chronic renal failure, estimates by CC formula were more accurate than those obtained by MDRD formula. Serum creatinine was the main source of error of the estimation of GFR by both formulas, though demographic and anthropometric characteristics influenced as well on their accuracies.     

Cystatin C in Acute Heart Failure Without Advanced Renal Impairment

Background

The prognostic value of cystatin C relative to glomerular filtration rate (GFR) estimated by the Modification of Diet in Renal Disease Study (MDRD) equation modified for Japan has not been investigated in acute heart failure patients with normal to moderately impaired renal function. More accurate detection of mild renal impairment might improve the risk stratification of heart failure patients, especially patients with normal to moderately impaired renal function.

Methods

Cystatin C and creatinine levels were measured on admission in 328 consecutive patients hospitalized for worsening chronic heart failure with a GFR estimated by MDRD equation modified for Japan ≥30 mL/min/1.73 m².

Results

During a median follow-up period of 915 days, there were 52 (16%) cardiac deaths. In stepwise Cox regression analyses including cystatin C and GFR estimated by MDRD equation modified for Japan (either as continuous variables or as variables categorized into quartiles), cystatin C (P <.0001), but not GFR estimated by MDRD equation modified for Japan, was independently associated with cardiac mortality. Adjusted relative risk according to the quartiles of these markers and Kaplan-Meier analyses revealed that the cystatin C was a better marker to separate low-risk from high-risk patients. Furthermore, receiver-operating characteristic curve analyses of these markers revealed that cystatin C showed a higher precision in predicting cardiac mortality.

Conclusion

Measurements of cystatin C might improve early risk stratification compared with GFR estimated by MDRD equation modified for Japan in acute heart failure patients with normal to moderately impaired renal function.     

Prognostic indicator by urinary microglobulin after renal stenting

Objective To evaluate the effect of revascularization of the renal artery on urinary microglobulin in patients with coronary artery disease and significant renal artery stenosis (RAS). Methods Forty-four patients with coronary artery disease and severe RAS (luminal narrowing >70%) underwent percutaneous transluminal renal artery angioplasty (PTRA) and stenting, as well as percutaneous coronary intervention. The urine -microglobulin (α1-MG) andβ2-Cmicroglobulin (β2-MG) at baseline and at 3 months after the procedures were measured. Procedural success rate, procedural complications, serum creatinine concentration at baseline and at 3-months were also recorded. Results At 3-months after the renal revascularization therapy, there was no significant change of urineα1-MG compared with that of the baseline, however, the urineβ2-MG decreased significantly 3-months after the treatment (237±187μg/L vs 377±173μg/L, P<0.01). Multivariate analysis revealed that persistent elevation of urine was an independent predictor of severe events (including re-admission and renal failure) after renal revascularization therapy in patients with severe RAS (OR=3.01, 95% CI 1.01-8.95, P=0.036). Conclusions In patients with coronary artery disease and severe RAS, revascularization with PTRA and stenting may improve renal tubular function, but a continuous high level of urinary microglobulins after intervention is associated with more frequent re-hospitalization and renal failure.     

阿托伐他汀改善对比剂对肾功能的短期影响

目的 观察阿托伐他汀对冠状动脉造影患者肾功能、尿微量蛋白及超敏C反应蛋白(hsCRP)改变的影响.方法 120例单纯冠状动脉造影的患者随机分为他汀组(60例)或对照组(60例),他汀组于冠状动脉造影术前2～3 d始每晚顿服阿托伐他汀20 mg,对照组未服用阿托伐他汀及其他调脂类药.所有患者分别于术前、术后第1天、第2天测定血清肌酐(Scr)及尿素氮(BUN);留尿标本检测尿α1-微球蛋白(α1-MG)、尿转铁蛋白(TRF)和尿微量白蛋白(mALB);测血浆胱抑素C(Cys C)、hsCRP,并根据Cockcrofi-Gauh公式和GFR(ml/min)=74.835/Cys C1.333公式分别计算出肌酐清除率(Ccr)和肾小球滤过率(GFR).结果 (1)对照组:与术前相比,术后第1天α1-MG、TRF、mALB、Cys C及hsCRP均有显著升高(P＜0.01);与术后第1天比较,术后第2天α1-MG、TRF、mALB、Cys C均有显著降低(P＜0.01),但α1-MG、Cys C仍高于术前水平(P＜0.01),而TRF、mALB已恢复到术前水平(P＞0.05);术后第2天hsCRP与术前第l天相比无明显变化(P＞0.05).(2)他汀组:与术前比较,术后第1天及第2天α1-MG、TRF、mALB、Cys C均无明显变化(P＞0.05);术后第1天hsCRP显著升高(P＜0.01);术后第2天hsCRP与术前第1天相比无明显变化(P＞0.05).(3)与他汀组相比较:对照组术后第1天α1-MG、TRF、mALB、Cys C及hsCRP均显著升高(P＜0.01);术后第2天Cys C、α1-MG及hsCRP仍显著升高(P＜0.01),但TRF、mALB均无统计学差异(P＞0.05).两组术前、术后BUN、Scr、Ccr均无明显变化(P＞0.05).结论 对比剂可造成轻微的一过性肾功能损害.阿托伐他汀于冠状动脉造影术前2～3 d给药,可能具有减轻炎症反应、改善患者一过性蛋白尿及GFR降低的作用,提示町能有预防对比剂肾病的作用.     

Differences between the glomerular filtration rate estimated by the MDRD equation and the measurement of creatinine and urea clearance in unselected patients with terminal renal insufficiency

From the results of the Modification of Diet in Renal Disease (MDRD) study, a prediction equation for a more accurate estimate of glomerular filtration rate (GFR), was developed. The present study ais to compare the GFR estimated by MDRD formula and that calculated by the average of creatinine and urea clearances in unselected patients with advanced renal failure. The study group consisted of 320 (163 males) with advanced renal failure not yet on dialysis. Their mean age was 63 +/- 14 years. Diabetic nephropathy was the most common etiology of renal failure (25%). Significant comorbidity was observed in 115 patients. Serum creatinine (Cr), urea and albumin were determined in all patients. Creatinine (Ccr) and urea clearance (Cu) were calculated on a 24-hour urine collection. The GFR was estimated by summing Ccr and Cu, and dividing by two (Ccr-Cu). THe clearances were corrected for a body surface area of 1.73 m2. The MDRD formula for the estimation of GFR included the following parameters: serum Cr, BUN, age, gender and serum albumin. Linear regression analysis and Bland-Altmann plot were utilized to establish the degree of correlation and agreement between both estimations of GFR. The percent differences between the two estimations of GFR was especially analyzed in those subgroups of patients which were not included in the MDRD study (patients older than 70 years, diabetics and those with comorbid conditions). The mean GFR estimated by Ccr-Cu and by MDRD formula were 10.04 +/- 3.10 ml/min and 10.55 +/- 3.60 ml/min, respectively (p < 0.0001). The two parameters correlated significantly (R = 0.76, p < 0.0001). GFR by the MDRD formula tended to overestimate the highest values of Ccr-Cu. The mean percent difference between both methods was 6.5 +/- 23.6. MDRD predictive equation overestimated significantly Ccr-Cu in patients older than 70 years (mean overestimation of 15%), males (10%), diabetics (10%), and mainly in patients with comorbidity (17%). In conclusion, the GFR estimated by MDRD formula is very similar to Ccr-Cu in young uremic patients without comorbidity. However, major discrepancies between these two methods could be observed in older patients, and mainly in those with comorbidity.     

Predictors of re-occlusion after successful recanalization of chronic total occlusion.

The objective of this study was to highlight the incidence and predictors of re-occlusion after successful recanalization of chronic total coronary occlusions. METHODS AND RESULTS: Following successful recanalization and stent implantation in 716 coronary lesions (665 patients) with chronic total occlusion, four hundred and five (56.6%) lesions (375 patients) underwent repeat angiography within 6 months. Restenosis (> or = 50% lumen narrowing) was observed in 151 (37.3%) lesions; forty-three (10.6%) of these lesions had complete re-occlusion and constituted the study population. In this group, final angiographic minimal lumen diameter (MLD) was 2.6 +/- 0.51 mm and final percent diameter stenosis was 18 +/- 11. Univariate analysis revealed significant correlation between re-occlusion and restenotic lesions, final balloon diameter, final percent diameter stenosis, final angiographic MLD, number of stents per lesion and total stent length. By multivariate analysis, the only independent predictor of re-occlusion was total stent length (OR = 1.46, 95% CI = 1.12-1.82; p = 0.0069). CONCLUSION: Re-occlusion occurs in about 11% of cases after stenting chronic total occlusion. The most important predictor of re-occlusion seems to be stent length.     

Renal fractional flow reserve: a hemodynamic evaluation of moderate renal artery stenoses.

The objective of this study was to perform a hemodynamic evaluation of moderate (50-90%) renal artery stenosis (RAS) under conditions of rest and maximum hyperemia. Identifying patients with RAS who have hemodynamically significant stenoses and are most likely to benefit from revascularization is clinically important. Current methods used to evaluate RAS, including angiography, have limitations. Physiologic evaluation of RAS may have a role in identifying patients with hemodynamically significant stenosis. Patients with suspected renovascular hypertension due to aorto-ostial RAS were included in the study. Hyperemia was induced by administration of intrarenal papavarine. Translesional pressure gradients were measured and renal fractional flow reserve (FFR) was calculated using a 0.014' pressure guidewire. Thirteen patients and 14 arteries with moderately severe (50-90%) RAS were studied. The mean translesional pressure gradient rose from a baseline of 6.3 +/- 3.9 to 17.5 +/- 10.8 mm Hg with maximal hyperemia. The renal FFR ranged from 0.58 to 0.95. There was a poor correlation between angiographic stenosis measurement and the renal FFR (r = -0.18; P = 0.54) and the hyperemic translesional mean pressure gradient (r = 0.22; P = 0.44). There was an excellent correlation between renal FFR and the resting mean translesional pressure gradient (r = -0.76; P = 0.0016) and the hyperemic mean translesional pressure gradient (r = -0.94; P < 0.0001). Selective renal arterial papavarine administration induces maximum hyperemia, permitting the calculation of renal FFR in renal arteries with aorto-ostial stenoses. The renal FFR correlates well with other hemodynamic parameters of lesion severity, but poorly with angiographic measures of lesion severity.     

Luminal recovery from six to twelve months after implantation of "thicker strut" coronary stents

A group of 50 patients with 51 de novo lesions treated with thicker strut stents (strut thickness >100 microm) was angiographically evaluated at baseline, after stenting, and at 6 and 12 months. Minimal luminal diameter (MLD) significantly increased from 6 to 12 months (6 months: 1.72 +/- 0.50 mm vs 12 months: 1.81 +/- 0.47 mm; p <0.01). The binary restenosis (diameter stenosis >50%) rate was 17% at 6 months and 11% at 12 months (p = NS). At multivariate analysis, lumen loss at 6 months (p = 0.018) and deployment pressure (p = 0.041) independently predicted the changes in MLD between 6 and 12 months.     

Simple cystatin C formula compared to sophisticated CKD-EPI formulas for estimation of glomerular filtration rate in the elderly

Despite the fact that the serum creatinine level is notoriously unreliable for the estimation of glomerular filtration rate (GFR) in the elderly, the serum creatinine concentration and serum creatinine-based formulas, such as the Modification of Diet in Renal Disease study equation (MDRD) are the most commonly used markers to estimate GFR. Recently, serum cystatin C-based formulas, the newer creatinine formula (the Chronic Kidney Disease Epidemiology Collaboration formula (CKD-EPI creatinine formula), and an equation that uses both serum creatinine and cystatin C (CKD-EPI creatinine and cystatin formula) were proposed as new GFR markers. The aim of our study was to compare the MDRD formula, CKD-EPI creatinine formula, CKD-EPI creatinine and cystatin formula, and simple cystatin C formula (100/serum cystatin C) against (51) Cr-EDTA clearance in the elderly. A total of 317 adult Caucasian patients aged >65 years were enrolled. In each patient, (51) Cr-EDTA clearance, serum creatinine, and serum cystatin C were determined, and the GFR was calculated using the MDRD formula, CKD-EPI formulas, and simple cystatin C formula. Statistically significant correlations between (51) Cr-EDTA clearance and all formulas were found. In the receiver operating characteristic (ROC) curve analysis with a cut-off of GFR 45 mL/min/1.73 m(2), a higher diagnostic accuracy was achieved with the equation that uses both serum creatinine and cystatin C (CKD-EPI creatinine and cystatin formula) than the MDRD formula (P < 0.013) or CKD-EPI creatinine formula (P < 0.01), but it was not higher than that achieved for the simple cystatin C formula (P = 0.335). Bland and Altman analysis for the same cut-off value showed that the creatinine formulas underestimated and the simple cystatin C formula overestimated measured GFR. All equations lacked precision. The accuracy within 30% of estimated (51) Cr-EDTA clearance values differ according to the stage of CKD. Analysis of the ability to correctly predict GFR below and above 45 mL/min/1.73 m(2) showed a high prediction for all formulas. Our results indicate that the simple cystatin C formula, which requires just one variable (serum cystatin C concentration), is a reliable marker of GFR in the elderly and comparable to the creatinine formulas, including the CKD-EPI formulas.     

Serum cystatin C concentration as a marker of glomerular filtration rate in patients with various renal diseases

OBJECTIVE: The present study was undertaken to evaluate clinical application of serum cystatin C as a new marker of glomerular filtration rate (GFR) in patients with various renal diseases. PATIENTS AND METHODS: A total of 140 patients were enrolled in the study. We measured the serum cystatin C levels and compared them with creatinine clearance (Ccr) and inulin clearance (Cin) as an indicator of GFR. RESULTS: There was a significant positive correlation between serum cystatin C and creatinine levels (r=0.928). Serum cystatin C was inversely correlated with creatinine clearance. Moreover, the reciprocal serum cystatin C level was positively correlated with Cin (r=0.882). The receiver-operating characteristic curve of serum cystatin C and creatinine demonstrated that the diagnostic accuracy of the serum cystatin C level is superior to that of creatinine in identifying individuals with reduced GFR. CONCLUSION: These results indicated that measurement of serum cystatin C is useful to estimate GFR, and in particular, to detect a mild reduction of GFR in patients with renal diseases.     

胱抑素C在评估慢性心力衰竭患者肾功能不全中的价值

目的观察慢性心力衰竭（CHF）患者的血清胱抑素C（Cys-C）、血清肌酐（Scr）、肾小球率过滤（eGFR）水平,评估Cys-C在CHF患者肾功能不全中的诊断价值。方法选取我院住院88例CHF的患者测定Cys-C、Scr,计算eGRF（简化MDRD公式）,根据eGFR水平将患者分成4组：GRF正常组、GRF轻度下降组、GRF中度下降组、GRF重度下降及肾衰竭组,比较4组间Cys-C、Scr的差异并进行Cys-C、Scr与GRF的相关性分析。结果 4组患者的血清Cys-C水平分别为（0.93±0.18）,（1.08±0.22）,（1.58±0.59）,（2.7±0.86）mg/L,差异有显著统计学意义（P〈0.01）,血清Cys-C与GRF显著相关,相关系数为0.62（P〈0.01）。结论 Cys-C可以作为肾小球滤过率的判断指标,有助于慢性心力衰竭患者肾功能不全的早期诊断。