The beneficial effects of calcium channel blockers on long-term kidney transplant survival are independent of blood-pressure reduction

There is a growing body of evidence suggesting that calcium channel blockers (CCB) exert beneficial effects on kidney transplant survival. However, it is not completely understood if these agents act independently of blood-pressure reduction. In the present study, the 5-yr follow-up of 45 kidney transplant recipients receiving CCB during the 60-month follow-up period was compared to that of recipients with lower blood pressure and an antihypertensive treatment without CCB. During the whole follow-up, systolic (127.4 +/- 2.5 vs. 139.4 +/- 2.1 mmHg, p < 0.05) as well as diastolic blood pressure (78.8 +/- 1.1 vs. 84.8 +/- 1.8 mmHg, p < 0.05) was higher in the group receiving CCB. Moreover, in CCB-treated recipients, a significant (p < 0.05) higher increase in proteinuria was detected (from 759 +/- 120 to 1690 +/- 359 mg/24 h vs. 180 +/- 45 to 340 +/- 45 mg/24 h). Despite higher blood pressure and higher proteinuria, the increase in serum creatinine in the group of CCB-treated recipients was significantly lower (0.01 mg/dL/month) in comparison to that of the controls (0.02 mg/dL/month, p < 0.05). Moreover, the 5-yr transplant survival was significantly higher in CCB-treated recipients (62.3 vs. 31.8%, p < 0.05). The results of the present study further support the beneficial effects of CCB in kidney transplant recipients, which are independent of blood-pressure reduction.     

Angiotensin-converting enzyme inhibitor or angiotensin II type 1 receptor antagonist therapy is associated with prolonged patient and graft survival after renal transplantation

Angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II type 1 receptor blockers (ARB) reduce cardiovascular death in the general population, but data for renal transplant recipients remain elusive. Similarly, ACEI/ARB have been shown to reduce proteinuria, but data on graft survival are lacking. Therefore a retrospective open cohort study was conducted of 2031 patients who received their first renal allograft at the Medical University of Vienna between 1990 and 2003 and survived at least 3 mo. Patient and graft survival was compared between patients with versus without ACEI and/or ARB therapy. Data were analyzed with and without propensity score models for ACEI/ARB therapy. Medication and comorbidities were analyzed as time-dependent variables in the Cox regression analyses. Ten-year survival rates were 74% in the ACEI/ARB group but only 53% in the noACEI/ARB group (P<0.001). The hazard ratio (HR) of ACEI/ARB use for mortality was 0.57 (95% confidence interval [CI] 0.40 to 0.81) compared with nonuse. Ten-year actual graft survival rate was 59% in ACEI/ARB patients but only 41% in nonusers (P=0.002). The HR of actual graft failure for ACEI/ARB recipients was 0.55 (95% CI 0.43 to 0.70) compared with nonusers; the HR of functional graft survival was 0.56 (95% CI 0.40 to 0.78). Ten-year unadjusted functional graft survival rates were 76% among ACEI/ARB patients and 71% in noACEI/ARB recipients (P=0.57). In summary, the use of ACEI/ARB therapy was associated with longer patient and graft survival after renal transplantation. More frequent use of these medications may reduce the high incidence of death and renal allograft failure in these patients.     

Renoprotective effect of triple therapy with low-dose angiotensin receptor blocker,low-dose diuretic and Ca-antagonist in hypertensive type 2 diabetic patients with overt nephropathy

Combination therapy with angiotensin receptor antagonist(ARB) plus angiotensin converting enzyme inhibitor(ACE-I) (ARB/ACE-I) was efficacious in reducing proteinuria in patients with progressive renal disease. However, this therapy may be associated with the worsening of anemia and hyperkalemia. The present study addressed whether or not triple therapy with low-dose ARB, low-dose diuretic (D) and calcium channel blocker(CCB) (ARB/D/CCB) is as effective as therapy with low-dose ARB/ACE-I in retarding the progression of overt diabetic nephropathy. In the triple therapy, the patients were initially subjected to monotherapy with CCB for 24 weeks. Low-dose ARB and low-dose D were added to the treatment for an additional 24-week period. In parallel, patients undergoing double therapy were initially treated with low-dose ACE-I alone for 24 weeks, and then low-dose ARB was added for an additional 24-week period. The results were as follows: 1) In the triple therapy, blood pressure was reduced by 9 mmHg in systole and 5 mmHg in diastole (not significant) compared to monotherapy with CCB. There was a significant decline in proteinuria (3.3 +/- 1.2 g/day in the CCB-treated period vs. 2.1 +/- 1.0 g/day in the ARB/D/CCB-treated period, n = 12, p = 0.0143). Furthermore, a significant improvement in the slope of reciprocal serum creatinine concentration(1/Cr) was found in response to triple therapy(1/Cr: -0.0118 +/- 0.0009 in the CCB-treated vs. -0.0035 +/- 0.0028(I/mg/dl/month) in the ARB/D/CCB-treated period, n = 12, p < 0.001). There was neither a worsening of anemia nor an increase in the serum potassium(K) concentration. 2) In the double therapy, blood pressure was reduced by 12 mmHg in systole(p = 0.0079, n = 11) and 6 mmHg in diastole(n = 11, p = 0.0037) compared to the monotherapy with ACE-I. A significant improvement in the slope of 1/Cr was found in the double therapy(1/Cr: -0.0095 +/- 0.0052 in the ACE-I treated period vs. -0.0029 +/- 0.0028(I/mg/dl/month) in the ARB/ACE-I, n = 11, p < 0.001). In addition, there was a substantial reduction in hematocrit and increase in serum K concentration. The present result suggests that triple therapy consisting of ARB/D/CCB is as efficacious as double therapy with ARB/ACE-I in protecting the kidney from the progression in patients with diabetic overt nephropathy. The former may be expected to have less adverse effects.     

ACE-inhibitor or AT2-antagonist therapy of renal transplant recipients is associated with an increase in serum potassium concentrations.

BACKGROUND: Angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II type 1 receptor blockers (ARB) are frequently prescribed to renal transplant recipients with a reduced glomerular filtration rate (GFR). The aim of this study was to investigate the association of ACEI/ARB use and serum potassium levels in renal graft recipients. METHODS: We conducted an open cohort study of 2041 first renal allograft recipients, transplanted at the Medical University of Vienna between 1990 and 2003. Serum potassium levels were compared over an up to 10 years of observation period between subjects with versus without ACEI/ARB therapy using a mixed effects general linear model. The analysis was adjusted for several covariables known to influence serum potassium such as the use of diuretics, beta blockers, calcineurin inhibitor (CNI) based immunosuppression, estimated GFR, time since renal transplantation, diabetes, years on dialysis and recipient age. RESULTS: The overall adjusted estimated serum potassium difference between recipients with versus without ACEI/ARB therapy was 0.08 mmol/l (P < 0.001). The use of diuretics was associated with a 0.11 mmol/l (P < 0.001) lower potassium concentration whereas each GFR decrease by 10 ml/min led to an increase of 0.04 mmol/l (P < 0.001). CNI intake increased serum potassium by 0.06 mmol/l (P = 0.002). Furthermore, serum potassium increased by 0.17 mmol/l within the first decade after transplantation (P < 0.001) while holding the other covariables constant. No effect modification between ACEI/ARB and time since transplantation was observed. Nineteen subjects (2.4%) discontinued the ACEI/ARB therapy due to hyperkalaemia. CONCLUSIONS: In summary, relevant hyperkalaemia associated with ACEI/ARB therapy is negligible in renal transplant recipients during long-term follow-up. The hyperkalaemic effect of ACEI/ARB is balanced by the use of diuretics.     

No improvement of patient or graft survival in transplant recipients treated with angiotensin-converting enzyme inhibitors or angiotensin II type 1 receptor blockers: a collaborative transplant study report

It was reported recently that treatment of kidney transplant recipients with angiotensin-converting enzyme inhibitors (ACEI) or angiotensin II type 1 receptor blockers (ARB) is associated with strikingly improved long-term graft and patient survival. This finding has important implications for future posttransplantation therapy recommendations. In an analysis of 17,209 kidney and 1744 heart transplant recipients, an association of treatment with ACEI/ARB with improved transplant outcome could not be confirmed. It is concluded that recommendations for a widespread use of ACEI/ARB treatment in transplant recipients are unwarranted.     

The association between angiotensin converting enzyme inhibitor or angiotensin receptor blocker use during postischemic acute transplant failure and renal allograft survival

BACKGROUND: Postischemic acute renal transplant failure occurs in approximately one fourth of all dead donor transplantations. Uncertainty exists regarding the putative association between the use of angiotensin converting enzyme inhibitors (ACEIs) or angiotensin II AT1 receptor blockers (ARBs) and kidney transplant graft survival in patients with delayed allograft function. METHODS: We conducted an open cohort study of all 436 patients who experienced an acute renal transplant failure out of all 2,031 subjects who received their first kidney transplant at the Medical University of Vienna between 1990 and 2003. Actual and functional graft survival was compared between users and nonusers of ACEI/ARB using exposure propensity score models and time-dependent Cox regression models. RESULTS: Ten-year actual graft survival averaged 44% in the ACEI/ARB group, but only 32% in patients without ACEI/ARB (P=0.002). The hazard ratio of actual graft failure was 0.58 (95% confidence interval: 0.35-0.80, P=0.002) for ACEI/ARB users compared with nonconsumers. Seventy-one percent of subjects with ACEI/ARB had a functional graft at 10 years versus 64% of ACEI/ARB nonusers (P=0.027). The hazard ratio of functional graft loss was 0.48 (95% confidence interval: 0.24-0.91, P=0.025). CONCLUSIONS: Use of ACEI/ARB in patients experiencing delayed allograft function was associated with longer actual and functional transplant survival.     

A randomized trial comparing losartan with amlodipine as initial therapy for hypertension in the early post-transplant period.

BACKGROUND: Blockade of the renin-angiotensin-aldosterone system in the early post-transplant period remains controversial. Angiotensin II-receptor blockers (ARB) have many benefits to the patient with chronic kidney disease and these benefits may also apply to the renal transplant recipient (RTR). Additionally, there are theoretical benefits of ARB use in RTR. This study was designed to investigate the safety of early ARB use after renal transplantation. METHODS: RTR with serum creatinine levels <3.0 mg/dl were randomized to receive either ARB (n = 29) or calcium-channel blocker (CCB; n = 27) as initial therapy for post-transplant hypertension. Differences in potassium, creatinine and haemoglobin concentrations were compared at baseline, 3, 6 and 12 months after transplantation. RESULTS: Withdrawal from the assigned treatment was high: 12 in the ARB group (due to hyperkalaemia in six) and 17 in the CCB group (due to intractable oedema in seven and post-transplant erythrocytosis requiring an angiotensin-converting enzyme inhibitor in seven). There were no differences in blood pressure, haemoglobin or creatinine concentration at any time-points. Mean potassium concentrations were only slightly higher in the ARB vs CCB group (range: 4.2-4.3 vs 3.7-3.8 mEq/l, respectively, but clinically significant) and the number of patients with potassium values >6.0 mEq/l was higher in ARB (n = 7) vs CCB (n = 1). CONCLUSIONS: These data suggest that hyperkalaemia is the major complication that occurs with the use of ARB in the immediate post-transplant period. ARB use does not affect renal function or complicate the post-transplant management of RTR. Other than reducing the incidence of post-transplant erythrocytosis, ARB use does not cause an excess incidence of anaemia. Strategies to reduce the risk of hyperkalaemia may allow increased use of ARB immediately after kidney transplantation.     

Therapeutic approaches in lowering albuminuria: travels along the renin-angiotensin-aldosterone-system pathway

Achieving optimal blood pressure and albuminuria control is a major therapeutic treatment goal in patients with renal insufficiency. Angiotensin-converting enzyme-inhibitors (ACEIs) and angiotensin-receptor blockers (ARB) are the mainstay of therapy in these patients. However, despite these therapies many patients remain at high risk of renal or cardiovascular disease that shows a relationship with albuminuria. Various approaches have been tested to maximize the efficacy of ACEI and ARB. Increasing the dose of an ACEI or ARB beyond the maximal registered antihypertensive dose causes a distinct decrease in albuminuria without additional effects on blood pressure. The combination of an ACEI and ARB is another possibility to further reduce albuminuria. However, the alleged beneficial effects on hard renal and cardiovascular outcome are not unambiguously demonstrated. Adding a direct renin inhibitor to an ACEI or ARB has been shown to lower albuminuria in patients with and without diabetes. Long-term trials are currently under way to determine the effects of direct renin inhibition on clinical outcomes. Volume excess has been shown to blunt the blood pressure and albuminuria response to ACEI or ARB therapy. Intervening in volume status by means of restricting dietary sodium intake or diuretic therapy has convincingly been shown to lower blood pressure and albuminuria. Whether this strategy translates into a reduction in the risk of renal or cardiovascular events has not (yet) been investigated in prospective randomized trials. Various options are at hand which have been shown to maximize the blood pressure and albuminuria response to ACEI and ARB treatment. However, long-term studies supporting the benefits of these strategies on hard renal and cardiovascular outcomes are warranted.     

Renin Angiotensin System Blockade in Kidney Transplantation: A Systematic Review of the Evidence

ACE-inhibitors and angiotensin receptor blockers (ARB) slow the progression of renal disease in non-transplant patients. A systematic review of randomized trials (n = 21 trials with 1549 patients) was conducted to determine the effect of ACE-inhibitor or ARB use following kidney transplantation. With a median follow-up of 27 months, ACE-inhibitor or ARB use was associated with a significant decrease in glomerular filtration rate (-5.8 mL/min; 95% CI -10.6 to -0.99). ACE-inhibitor or ARB use resulted in a lower hematocrit (-3.5%; 95% CI -6.1 to -0.95), reduction in proteinuria (-0.47 gm/d; 95% CI -0.86 to -0.08) but no change in the serum potassium (0.18 mmol/L; 95% CI -0.03 to 0.40). ACE-inhibitor or ARB use results in clinically important reductions in proteinuria, hematocrit and glomerular filtration rate in renal transplant recipients, but there are insufficient data to determine the effect on patient or graft survival. Randomized trials of sufficient power and duration that examine these hard outcomes should be conducted. Until such trials are completed, this study provides quantitative estimates of the risks and benefits of ACE-inhibitor or ARB use that can be used by clinicians considering prescribing these medications to kidney transplant recipients or to researchers designing future trials.     

Prevalence of anemia in renal transplant patients: results from MOST, an observational trial

INTRODUCTION: Anemia is one of the most common complications of chronic renal disease. However, the incidence or prevalence of anemia in kidney transplant recipients has not been well studied. The aim of this study was to assess the prevalence of anemia in renal transplant in early and late posttransplant period and the influence of drugs (immunosuppressive and antihypertensive). METHODS: MOST is an observational, prospective trial of renal transplant receiving cyclosporine-based immunosuppressive regimen under condition of normal practice in de novo or maintenance recipients. We analyzed the Spanish data from 397 de novo recipients and 2102 maintenance recipients. RESULTS: In maintenance recipients mean hemoglobin levels were 12.8 +/- 1.6 g/dL (13.2 +/- 1.7 in men and 12 +/- 1.4 in women); 22.73% of men and 20.19% of women were found to be anemic. There was a significant correlation between hemoglobin and graft function (r = .14, P < .0001). The percentage of patients with anemia increased with the severity of chronic renal disease according to the KDOQI classification. Therapy with mycophenolate mofetil was also associated with a higher likehood of anemia as compared with other immunosuppressive therapies (azathioprine or sirolimus). There were no differences with angiotensin-converting enzyme inhibitors or ARB II. In de novo patients postransplant anemia was a frequent complication during the first 3 to 6 months. In patients with delayed graft function the recovery of anemia was slower. CONCLUSION: The prevalence of anemia in transplant recipients was remarkably high, especially in the early postransplant period, and appeared associated with impaired renal function and with immunosuppressive treatment.     

Long‐term outcomes of transplant recipients referred for angiography for suspected transplant renal artery stenosis

Our aim was to study the long‐term outcomes of all transplant recipients who underwent angiography for suspected TRAS at our institution. The patients were divided into TRAS+ve and TRAS?ve groups based upon angiographically confirmed results. TRAS was confirmed in 58.1% of 74 patients with median time of 8.9 months. Primary angioplasty alone was performed in 56% of patients with TRAS, while the remaining had PTA with stent (PTAS). There was reduction in systolic and diastolic BP (165 ± 19–136 ± 15 mmHg and 82 ± 14 mmHg to 68 ± 12 mmHg; p < 0.05) and number of antihypertensive drugs (3.5 ± 0.9–2.7 ± 1.0; p < 0.05). Overall, graft survival and patient survival from time of transplant were similar in both groups. Graft function was similar for the patients with treated TRAS+ve as compared to TRAS?ve over time. Graft survival and patient survival when compared to an age‐ and year of transplant‐matched cohort control group were also similar. In conclusion, angiography for suspected TRAS is more likely to yield a confirmatory result early in the transplant course as compared to late. Treatment of TRAS in these patients had sustained long‐term graft function. Alternative etiologies of HTN and graft dysfunction should be sought for recipients further out from transplant.     

Cardiovascular and renal protection in type 2 diabetes mellitus: the role of calcium channel blockers

The most important factor that prevents the progression of renal damage in diabetes mellitus, beside the improvement of blood glucose control, is tight BP control. The tenet of tight BP control may be defined as the lowest BP level one can accomplish using antihypertensive therapy that is at the same time compatible with the absence of untoward side effects. In fact, both the Framingham Heart Study in nondiabetic normal subjects and the United Kingdom Prospective Diabetes Study in type 2 diabetic patients showed that systolic values as low as 108 to 111 mmHg and diastolic values as low as 70 to 71 mmHg are significantly associated with decreased cardiovascular mortality and morbidity. However, 45 to 50% of the patients with type 2 diabetes mellitus and hypertension have systolic BP levels above 140 mmHg during antihypertensive therapy, particularly when using monotherapy. Thus the issue regarding the choice of which drugs one should use to treat hypertension became critical from a clinical point of view. Pharmaceutical compounds, which inhibit the renin-angiotensin system, have become the first-choice treatment in patients with diabetes mellitus and incipient and advanced renal complications. The present brief review analyzes the effects of calcium channel blockers (CCB) on cardiovascular and renal complications in diabetes mellitus. The review discussed those studies that directly and blindly compared CCB with angiotensin-converting enzyme (ACE) inhibitors and with angiotensin II AT(1) receptor blockers (ARB). Furthermore, size of the population recruited in each trial was used as a criterion of priority in the selection of the reports from the available literature. From the point of view of cardiovascular complications, the results of these studies showed a slightly better benefit of CCB on stroke, whereas ACE inhibitors better prevented the occurrence of myocardial infarction and congestive heart failure. On the other hand, recent observations demonstrated that also ACE inhibitors and ARB are effective in the primary and secondary prevention of stroke, although these studies did not directly compare these compounds with CCB. With regard to the outcome of renal complications, both ARB and ACE inhibitors more effectively prevented the progression of renal damage among the patients with overt nephropathy than CCB. On the contrary, both CCB and ACE inhibitors were equally effective on blunting the decay of GFR in diabetic patients who do not have overt proteinuria. However, ACE inhibitors and ARB more markedly decreased the rate of albumin excretion rate in the range of both microalbuminuria and macroalbuminuria. Recent advances in the understanding of the pathogenesis of abnormalities of albumin excretion rate and of atherosclerosis are also discussed. Both mechanical stress, mainly secondary to systolic hypertension, and elevated circulating and tissue levels of angiotensin II, partially independent from each other, cause excessive generation of superoxide compounds. This chain reaction of events in turn leads to disorders of structural components of glomerular filter and to damage of the vascular wall. Systolic BP control (<130 mmHg) is not adequately accomplished in the majority of the patients treated only with ACE inhibitors and ARB, even in association with diuretics. Poor BP control may lead to excessive systemic mechanical stress at the vascular level despite satisfactory inhibition of angiotensin II effects. In conclusion, one can suggest that CCB are useful and often indispensable pharmaceutical compounds, beside ACE inhibitors and ARB, to accomplish tight BP control (<130/85 mmHg), a target that is unlikely to be successfully maintained in the overall population of type 2 diabetic patients only by ACE inhibitors or ARB, as monotherapy. However, ACE inhibitors and ARB might be considered first-choice drugs in the treatment of hypertension in diabetes mellitus, mainly because of a better renoprotection.     

Enalapril/amlodipine combination in cyclosporine-treated renal transplant recipients: a prospective randomized trial

BACKGROUND: Most hypertensive renal transplant recipients require two or more antihypertensive medications to achieve blood pressure control. However, which medications must be combined is still a matter of debate. METHODS: A prospective randomized open-label blinded evaluation trial comparing the six-month effects of the amlodipine-enalapril combination (n = 32) vs. enalapril alone (n = 33) and vs. amlodipine alone (n = 34) on arterial pressure, renal function, albuminuria and tolerability. RESULTS: At six months, diastolic arterial pressure was more adequately controlled (i.e., <90 mmHg) in the combination group than in the amlodipine and enalapril groups (100% vs. 82.4% and 84.8%, respectively, p = 0.038). The same trend was observed for systolic arterial pressure (65.6% vs. 58.8% and 51.5%, NS). The six-month change in albuminuria was similar in the combination group and in the enalapril group (-64.7% vs. -59.5%); however, patients in the combination group exhibited a greater reduction in albuminuria than in the amlodipine group (-64.7% vs. -29.0%, p = 0.002). As compared with baseline values, serum creatinine and potassium remained unchanged in the combination group, whereas they increased by 9 +/- 12 micromol/L (p = 0.01) and by 0.2 +/- 0.4 mmol/L (p < 0.01), respectively, in the enalapril group. The cyclosporine trough levels remained unchanged in the combination group, but increased in the amlodipine group. CONCLUSION: Angiotensin-converting enzyme inhibitor (ACEI)-calcium-channel blocker (CCB) combination controls arterial pressure more adequately than ACEI alone or CCB alone, reduces albuminuria and may prevent the ACEI-induced initial rise in serum creatinine.     

Impact of genetic polymorphisms of the renin–angiotensin system and of non-genetic factors on kidney transplant function – a single-center experience

Abstract:  Renin–angiotensin–aldosterone system (RAAS) polymorphisms such as the angiotensinogen-gene-M235T-, the angiotensin-conversion enzyme (ACE)-gene I/D- and the angiotensin-II-type 1-receptor-(AT₁R)-A1166C-polymorphism have been implicated in renal insufficiency and hypertension. We studied the association of these RAAS genotypes and non-genetic factors with transplant function and hypertension after renal graft transplantation (NTX). A total of 229 renal graft recipients, transplanted at a single center, were monitored up to 54 months and genotyped using polymerase chain reaction. The prevalence of the genotypes was comparable to a control group of healthy volunteers. Genotype and clinical outcome was analyzed using anova , while the k -nearest neighbor method was used for a pattern recognition analysis of the complete database. Hypertension after NTX was not influenced by the RAAS polymorphisms. The DD-genotype of the ACE-I/D-polymorphism was associated with significantly deteriorated renal transplant function during the months 18 to 30 after transplantation according to anova at p < 0.05, as were non-genetic factors like long hospitalization, poor primary transplant function, and frequent rejections. Pattern recognition identified, the use of cyclosporine (odds ratio of 4.25) and the use of Ang II-receptor-blockers at discharge indicating the need of effective antihypertensive treatment (odds ratio of 3.26) as risk factors for transplant function loss. Altogether, the significant impact of the DD-genotype on the outcome after renal transplantation emphasizes the early identification of RAAS genotypes.     

Randomized prospective study of effects of benazepril in renal transplantation: an analysis of safety and efficacy

Background. Prolonging the survival of transplanted kidneys is one of major tasks of modern nephrology. Angiotensin-converting enzyme inhibitors (ACEIs) compose a class of antihypertensive agents that has established efficacy in the treatment of hypertension and in slowing the progression of diabetic nephropathy and chronic glomerulonephritis. ACEIs are not widely accepted as a standard medication in the treatment of hypertension in renal transplant recipients because of the potential risk for decreased renal blood flow and glomerular filtration rate associated with a single kidney and concomitant cyclosporin use. Methods. We undertook a prospective randomized study of ACEI (benazepril) treatment in 76 posttransplant patients to determine the safety, efficacy, and side-effect profile of benazepril. Forty-one patients were assigned to the benazepril group and 35 patients were assigned to the control group. Results. The mean arterial blood pressure at a 12-month follow-up was lower than that at the time of initiation of benazepril or control therapy, with a decrease from 101 ± 10 mmHg to 94 ± 7 mmHg (P < 0.05) in the benazepril group and from 102 ± 12 mmHg to 94 ± 10 mmHg in the control group after 12 months of treatment. The serum creatinine concentrations did not change throughout the follow-up period. Conclusions. Benazepril was demonstrated to be an effective antihypertensive without any unfavorable effects on graft function. A significant antiproteinuric effect of benazepril was observed in patients with overt proteinuria. Further follow-up of this patient population will contribute to the establishment of the long-term renoprotective effect of benazepril in renal allograft recipients. Received: June 12, 2002 / Accepted: August 5, 2002 Correspondence to:T. Moriyama     

肾移植术后将CCB替换为ARB控制高血压和蛋白尿的效果

目的 研究肾移植术后将钙通道阻滞剂(CCB)替换为血管紧张素受体阻滞剂(ARB)控制肾移植远期高血压和蛋白尿的有效性和安全性.方法 将肾移植术后5～20年,并服用CCB药物治疗高血压的127例受者纳入研究,所有受者均无糖尿病,移植肾功能保持稳定.采用随机数字表法将受者分为2组,实验组65例,纳入研究前受者均单用CCB,纳入研究后停用CCB,改用氯沙坦50～100 mg/d;对照组62例,维持CCB用药不变.对两组受者进行随访,随访时间为2年,观察血、尿常规,肝、肾功能,血脂,电解质,24 h尿蛋白定量,以及CNI血药浓度等指标的变化.结果 随访期间,两组受者的血压均能保持在正常水平.实验组受者24h尿蛋白定量由随访前的(176.32±54.54)mg下降至随访2年时的(155.69±62.25)mg,差异有统计学意义(P＜0.05);随访2年时,对照组受者的尿蛋白水平略有上升,但差异无统计学意义(P＞0.05);实验组受者的血脂水平与随访前相比,差异无统计学意义(P＞0.05),但高密度脂蛋白水平由随访前的(2.25±0.26)mmol/L升高到随访2年时的(2.46±0.31)mmol/L,差异有统计学意义(P＜0.05).两组受者随访前与随访2年后的血常规、肝肾功能、血钾及CNI血药浓度等检查指标的差异均无统计学意义.结论 肾移植术后远期使用CCB和ARB治疗高血压都是安全、有效的,而应用ARB对于减少蛋白尿和降低心血管事件的风险可能会更好.     

Renin-angiotensin system blockade in biopsy-proven allograft nephropathy

Allograft nephropathy leads to progressive renal injury and ultimate graft loss. In native kidney disease, the use of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) is beneficial in retarding the decline of renal function. We reviewed a cohort of renal transplant recipients who were prescribed either an ACEi or ARB for biopsy-proven allograft nephropathy. Patients were followed from time of initiation of ACEi/ARB and were stratified based on biopsy findings. Outcomes of interest included safety, allograft survival, renal function, and rate of renal function decline pre- and post-ACEi/ARB. The 5-year allograft survival after biopsy was 83%. Mean serum creatinine was 2.2 +/- 1.1 mg/dL (range 1.0 to 4.3) at time of biopsy and 2.6 +/- 1.2 mg/dL (1.2 to 6.5) at last follow-up. The mean slope of the creatinine versus time (SD) was 2.43 (7.93) in the 12 months prior to therapy and 1.45 (3.66) following therapy, with the absolute difference in slope -3.38 (6.06) (P =.0004). We conclude that treatment with ACEi/ARB is beneficial in the management of allograft nephropathy.     

The effect of aldosterone blockade in patients with Alport syndrome

Recent studies indicate that adding the mineralocorticoid receptor antagonist spironolactone (SP) to angiotensin converting enzyme inhibitors (ACEI) or ACEI and angiotensin receptor blocker (ARB), which is known as a triple blockade, enhances the more beneficial effects on urinary protein excretion of patients with chronic kidney diseases. In this study, we explored the effects of SP on urinary protein excretion in patients with Alport syndrome featuring persistent proteinuria in spite of the long-term use of ACEI (lisinopril) or both ACEI and ARB (candesartan). Five patients with Alport syndrome were enrolled and SP treatment (25 mg/day) was started. At the start of SP administration, all patients showed good renal function and none of them suffered from hypertension. We decided to assess the effect of SP by determining the morning urinary protein/creatinine ratio (U-P/C) and estimated glomerular filtration rate (EGFR). After SP treatment was started, U-P/C was significantly reduced at 3, 6, 12 and 18 months, while EGFR did not change. The drop in systolic and diastolic blood pressure was statistically significant and serum potassium level was slightly elevated. None of the patients showed signs of severe hyperkalemia (>5.0 mEq/l). These results suggest that aldosterone receptor blockade combined with ACEI and ARB therapy offers a valuable adjuvant treatment for the reduction of proteinuria in patients with Alport syndrome as in those with other chronic kidney diseases. SP can thus be expected to constitute a good renoprotective agent for Alport syndrome. These preliminary data indicate that large-scale trials of this therapy should be done.     

Improved Long-Term Outcomes After Renal Transplantation Associated with Blood Pressure Control

Hypertension has a negative impact on long-term outcomes after renal transplantation. We investigated the effect of a recent decline in blood pressure among renal transplant patients in the Collaborative Transplant Study (CTS) database on long-term graft and patient survival. CTS data were used to evaluate transplant outcomes in relation to recipient systolic blood pressure (SBP) for 24,404 first cadaver kidney recipients transplanted between 1987 and 2000. Patients whose SBP was > 140 mmHg at 1 year posttransplantation but controlled to < or = 140 mmHg by 3 years had significantly improved long-term graft outcome compared with patients with sustained high SBP to 3 years (RR 0.79; CI 0.73-0.86; p < 0.001). Additional examination at 5 years showed that SBP lowering after year 3 was associated with improved 10-year graft survival (RR 0.83; CI 0.72-0.96; p = 0.01), whereas even a temporary increase in SBP at 3 years was associated with worse survival (RR 1.37; CI 1.19-1.58; p < 0.001). Changes in SBP were paralleled by changes in the incidence of cardiovascular death among recipients younger than 50 but not in older recipients. Lowering SBP, even after several years of posttransplantation hypertension, is associated with improved graft and patient survival in renal allograft recipients.