Hypertension and kidney transplantation

Duplex-Doppler Long-term Follow-up of Renal Transplant Artery Stenosis: Case Controlled Study

The aim of this retrospective clinical study was to assess a long-term course of renal transplant artery stenosis with duplex-Doppler ultrasound, and its influence upon serum creatinine, hemoglobin concentration and hypertension, as well as to investigate a possible association between stenosis and the number of acute rejections. Thirty-four renal transplant recipients, aged 43 +/- 13 years, with significant (>50%) renal transplant artery stenosis as seen on Doppler ultrasound were compared with 34 renal transplant recipients without stenosis (excluded by Doppler). Patients of both groups were matched by age, sex, time of transplantation, type of renal transplant, and number of previous transplantations. We analyzed peak systolic velocity (PSV) in the renal transplant artery, resistance index (RI) at the level of intra-renal arteries, serum creatinine, hemoglobin concentration, blood pressure, the number of antihypertensive medications, and the number of acute rejections on a yearly basis. In the stenosis group, PSV was 2.1 +/- 0.5 m/s at 1 year after transplantation (controls 1.1 +/- 0.4), 1.9 +/- 0.5 at 2 years (0.9 +/- 0.4), 1.9 +/- 0.5 at 3 years (0.9 +/- 0.4); RI was 62 +/- 10% at 1 year (controls 68 +/- 7), 65 +/- 9 at 2 years (67 +/- 7), 63 +/- 9 at 3 years (67 +/- 7); serum creatinine was 128 +/- 58 micromol/L at 1 year (controls 129 +/- 43), 119 +/- 47 at 2 years (121 +/- 33), 125 +/- 54 at 3 years (127 +/- 32). Long-term course of renal transplant artery stenosis (>50%), treated medically or interventionally, seems to be stable and non-progressive (during a 3-year follow up). Spontaneous regression of stenosis to non-significant level is possible. No difference in graft function, blood pressure or the number of acute rejections was observed comparing the stenotic and non-stenotic groups.

Early immunologic and nonimmunologic predictors of arterial hypertension after renal transplantation

We followed up a cohort of 680 renal transplant recipients receiving cyclosporine (CsA) immunosuppression with the aim of establishing an early-risk profile for early and late hypertension (HT) after renal transplantation (RTx), specifically comparing the predictive role of immunologic and nonimmunologic markers of graft prognosis. HT was defined as the need for antihypertensive drugs. The prevalence of HT was 65% at the time of RTx, increased to a peak of 78% at the end of the first year, and stabilized between 71% and 73% thereafter. Multivariate analysis identified HT at the time of RTx, basal renal disease, and grafting the right kidney as independent predictors of HT 3 months after RTx. The risk profile for HT 12 months after RTx included HT present at RTx, grafting the right kidney, markers of early ischemia-reperfusion injury (delayed graft function, cold and warm ischemia), and transplant from an elderly or female donor. Polytransfusion before RTx was associated with a decreased risk for HT, but retransplantation, increased reactivity against the lymphocyte panel, poor HLA compatibility, and early acute rejection did not portend an increased risk for the complication under study. The CsA schedule (dose, trough levels) correlated poorly with the blood pressure status of the patients, but simultaneous graft function was independently associated with late HT. In conclusion, the early predictive profile for HT after RTx includes, preferentially, nonimmunologic markers of graft prognosis. Hyperfiltration damage may be a significant pathogenic mechanism for this complication of RTx.

Percutaneous transcatheter renal ablation with absolute ethanol for uncontrolled hypertension or nephrotic syndrome: results in 11 patients with end-stage renal disease

PURPOSE

Retrospective review of authors' experience with percutaneous transcatheter renal ablation in patients with uncontrolled hypertension and/or nephrotic syndrome.

MATERIALS AND METHODS

Between April 1987 and September 1995, renal ablation was performed on 11 patients aged 10 months to 21 years. All patients had end-stage renal disease (ESRD) with uncontrolled hypertension (10 patients) and/or nephrotic syndrome (four patients). Uncontrolled hypertension was defined as diastolic pressure greater than 90 mm Hg despite multidrug antihypertensive therapy. Nephrotic syndrome was defined as proteinuria exceeding 960 mg/m2 per day, serum albumin level less than 3 g/dL, and generalized edema. Embolization was performed with absolute ethanol from a common femoral artery approach. In most cases, a balloon catheter was used to prevent alcohol reflux into the aorta or nontarget renal artery branches, such as the adrenal arteries. Angiographic stasis of contrast material in the renal arteries was the endpoint.

RESULTS

All patients experienced a postembolization syndrome of 3-5 days duration, clinically manifested by variable degrees of nausea, vomiting, fever, and pain. Long-term improvement in hypertension was observed in nine patients. Improvement in hypertension was defined as diastolic blood pressure below 90 mm Hg while the patient received the same or fewer antihypertensive medications. The four patients with nephrotic syndrome were cured of their proteinuria and edema.

CONCLUSIONS

Transarterial renal ablation with alcohol is efficacious for treatment of uncontrolled hypertension and nephrotic syndrome in patients with ESRD. The morbidity and mortality in our series were less than those reported for surgical nephrectomy.

Conversion from cyclosporine A to azathioprine treatment improves LDL oxidation in kidney transplant recipients

The use of the immuno-suppressant cyclosporine A (CsA) after transplantation has been associated with less favorable plasma lipid profiles, which may contribute to the high incidence of cardiovascular morbidity and mortality in transplant recipients. Recent studies have suggested that oxidative modification of LDL plays an important role in the initiation and progression of atherosclerosis. It has also been demonstrated that CsA may facilitate lipid peroxidation in vitro and in vivo. Therefore, we determined several parameters of LDL oxidizability in renal transplant recipients who were switched from CsA to azathioprine (AZA)-based immunosuppressive treatment. The susceptibility of LDL to in vitro oxidation, LDL particle size, plasma titers of IgG and IgM antibodies against oxidized LDL and plasma LDL subclass patterns in 19 renal transplant recipients were determined during CsA treatment and 16 weeks after these patients were converted to AZA treatment. In addition, mean arterial pressure was recorded, and glomerular filtration rate and renal blood flow were estimated from the clearance of radiolabeled thalamate and hippurate. After conversion, the plasma concentrations of total cholesterol, LDL cholesterol and triglyceride decreased, while plasma HDL cholesterol did not change. During CsA therapy plasma LDL was significantly more susceptible to in vitro oxidation than during AZA, as reflected by a longer lag phase during in vitro oxidation (98.9 +/- 24.3 vs. 114.7 +/- 17.3 min, P = 0.031). In addition, the LDL size increased (236.5 +/- 7.3 vs. 240.7 +/- 6.8 nm, P = 0.00001), and the titers of IgM- and IgG-autoantibodies against oxidized LDL decreased significantly after patients were converted from CsA to AZA. The more atherogenic LDL subclass pattern B was present in 13 out of 19 patients during CsA. In five patients, pattern B changed into pattern A after conversion. The subclass B pattern was maintained in eight patients and subclass A pattern in six patients. In all patients the lag time of in vitro LDL oxidation increased, although the biggest changes were found in those patients in whom the LDL subclass changed from pattern B to pattern A. Mean arterial pressure decreased and renal function improved significantly after conversion. No correlation between parameters of lipid peroxidation and changes in blood pressure or renal function upon conversion, underlying renal disease, time since transplantation, or antihypertensive treatment was found. Our study demonstrates that treatment with CsA increases the susceptibility of LDL to in vitro oxidation, and also enhances the oxidation of LDL in vivo. In addition, conversion to AZA results in a more favorable lipid profile, which in combination with a lower arterial pressure and better renal function may decrease the risk for atherosclerosis. These factors may account for the cardiovascular complications during CsA treatment after organ transplantation, and also when CsA is used for other diseases.

Relationships between arterial hypertension and renal allograft survival in African-American patients

In previous studies, we showed that in African-American patients arterial hypertension during the first 6 months after transplantation is associated with a high risk of renal allograft loss. In this study, we sought to examine the relationships between pretransplant blood pressure (preBP), blood pressure early after transplantation (postBP), and allograft function and survival. The study included 116 African-American recipients of first cadaveric renal allografts followed for 64 +/- 40 months. Prior to transplantation, 78% of the patients required antihypertensive medications and 59% had poorly controlled BP (average mean arterial pressure, > or =107 mm Hg). Blood pressure levels increased significantly during the first month posttransplant, particularly in patients with poorly controlled preBP. During the first 6 months posttransplant, 95% of patients required antihypertensive drugs; after the transplant, patients required significantly more and higher doses of antihypertensives compared with pretransplant. In 38% of the patients, postBP remained high despite therapy. The level of postBP correlated with the patient's weight pretransplant and with the level of preBP. Pretransplant BP correlated with postBP 1 month after transplantation (r = 0.4, P < 0.0001), and 70% of the patients with poorly controlled postBP had uncontrolled preBP. Patients with poorly controlled preBP had worse graft survival than patients with well-controlled preBP (P = 0.03 by Cox regression). Furthermore, compared with patients with well-controlled postBP, patients with high postBP had higher serum creatinine at 10 days (P = 0.04) and at 6 months (P = 0.0004) posttransplant; these patients had reduced graft survival (P = 0.0006 by Cox). We found no objective evidence of differences in patient compliance between individuals with high postBP and those with well-controlled postBP. This study confirms the association between high postBP and reduced renal allograft survival in African-American patients. In addition, these results show that the level of preBP can be used to identify patients at high risk of developing severe hypertension immediately after transplantation and those at risk for renal allograft failure.

Pharmacology of immunosuppressive medications used in renal diseases and transplantation

As understanding of the molecular basis for the immune response has expanded rapidly, so have the possibilities for designing therapeutic interventions that are more effective, more specific, and safer than current treatment options. The promise of therapeutic advances in the future is based on the rapidly expanding insights into the pathogenesis of abnormal immunologic reactions. Nowhere is the understanding of molecular mechanisms, pathophysiology, and targeted therapy more relevant than in the field of renal transplantation, which makes up much of the clinical database for the use of immunosuppressive therapy for renal disease. Despite the recent advances in basic immunology, clinical validation of new agents and approaches is lacking for most drugs at present. This review will focus in the pharmacology of agents used in the therapy of immunologic renal disease and in renal transplantation. It should be recognized that clinical pharmacology and experience with newer agents is limited, and potential utility is based largely on experimental data.

Increased low density lipoprotein oxidation in stable kidney transplant recipients

We studied factors that may add to the high risk of atherosclerosis in kidney transplant recipients. Plasma lipoprotein concentrations and parameters of low density lipoprotein (LDL) oxidation were determined in 19 clinically stable kidney recipients and 19 healthy controls. Plasma triglycerides and total cholesterol were increased in the patients. High density lipoprotein-cholesterol (HDL-c) was in the normal range. The mean LDL diameter was smaller in patients than in controls (236.5 +/- 7.3 A vs. 247.8 +/- 11.6 A, P < 0.002), which was due to a higher frequency of the LDL subclass pattern B in the patients than in controls (58% vs. 28%). The lag time of copper-induced in vitro LDL oxidation was shorter in patients than in controls (101 +/- 23 min vs. 148 +/- 81 min, P = 0.02). The titer and concentration of autoantibodies against malondialdehyde-modified (MDA-LDL) determined by ELISA were higher in the patients than in the controls. This difference was found in both IgG (titer + 9%, concentration + 75%; P < 0.05) and IgM (titer + 35%, concentration + 102%; P < 0.001). Based on these results, we propose that there is in vitro and in vivo evidence of enhanced LDL oxidation in patients post-renal transplantation. This might represent one cause for the clinical finding of advanced atherosclerosis in these patients.

Racial differences in renal allograft survival: the role of systemic hypertension

The rate of decline in the number of functioning renal allografts beyond the first year after transplantation has changed little in the last 25 years, and during long-term follow-up most allografts are lost due to chronic transplant rejection or patient death. The recipient race correlates with allograft survival, and African American recipients have a lower allograft survival than Caucasians. The goal of the present study was to identify clinical variables present during the first six months after transplantation that predict the loss of renal allografts beyond six months after transplantation, and in particular to determine the role of systemic hypertension on renal allograft survival in black and white recipients. This study includes 547 recipients of first cadaveric renal allografts performed at The Ohio State University. All patients were treated with a uniform immunosuppressive protocol and had a follow-up of at least three years. By multivariate analysis the following variables correlate with poor allograft survival: an elevated serum creatinine concentration measured six months after transplantation (SCr6mo) (P < 0.0001); black race (P < 0.0001); increasing numbers of acute rejection episodes (ATR) (P = 0.002); and young recipients (P = 0.026). Allograft survival is significantly worse in black (mean allograft half-life of 7.7 +/- 1.3 years) than in white recipients (24 +/- 3 years) (P < 0.0001). Black recipients also have a significantly higher six month average mean arterial blood pressure (MAP) (105 +/- 8 mm Hg) than white recipients (102 +/- 7 mm Hg) (P = 0.002). However, the prevalence of hypertension is not significantly different in black (33%) than in white recipients (26%).(ABSTRACT TRUNCATED AT 250 WORDS)

Cyclosporine-induced hypertension after transplantation

OBJECTIVE

To describe the features and mechanisms of posttransplantation hypertension and suggest appropriate management of the disorder.

DESIGN

We review our own experience and reports from the literature on hypertension in cyclosporine A (CSA)-treated transplant recipients.

RESULTS

Soon after immunosuppression with CSA and corticosteroids, hypertension develops in most patients who undergo transplantation. The blood pressure increases, which are usually moderate, occur universally because of increased peripheral vascular resistance. Disturbances in circadian patterns of blood pressure lead to loss of the normal nocturnal decline, a feature that magnifies hypertensive target effects. Changes in blood pressure sometimes are severe and associated with rapidly developing target injury, including intracranial hemorrhage, left ventricular hypertrophy, and microangiopathic hemolysis. The complex mechanisms that underlie this disorder include alterations in vascular reactivity that cause widespread vasoconstriction. Vascular effects in the kidney lead to reduced glomerular filtration and impaired sodium excretion. Many of these changes affect local regulation of vascular tone, including stimulation of endothelin and suppression of vasodilating prostaglandins. Effective therapy includes use of vasodilating agents, often calcium channel blocking drugs. Caution must be exercised to avoid interfering with the disposition of CSA or aggravating adverse effects relative to kidney and electrolyte homeostasis.

CONCLUSION

Recognition and treatment of CSA-induced hypertension and vascular injury are important elements in managing the transplant recipient.

Laparoscopic bilateral nephrectomy for renin-mediated hypertension

Hypertension arising from retained native kidneys complicates the management of recipients of renal transplants. Reluctance to administer angiotensin-converting enzyme inhibitor (ACEI) drugs to patients taking cyclosporine has reopened the question of performing native nephrectomies for poorly controlled, renin-dependent hypertension. We report the first published cases of simultaneous bilateral laparoscopic nephrectomies in 2 patients: 1 in preparation for living-related donor transplantation and the other ten months following cadaver transplantation in a patient whose end-stage renal disease was from malignant nephrosclerosis. Both had very severe hypertension resistant to multiple drugs and both became normotensive with little or no antihypertensive medication following nephrectomies. A bilateral nephrectomy is currently feasible using a laparoscopic approach.

De novo hypertension after liver transplantation

Hypertension develops in most patients after transplantation when immunosuppression is based on cyclosporine and prednisone. The pathogenesis appears to be multifactorial but involves rapidly rising vasoconstrictor tone in renal and systemic vascular beds. Much of this tone reflects abnormal vascular function, characterized by impaired prostacyclin and EDRF effects, in conjunction with increased vasoconstriction due to endothelin and possibly other factors. Effective management of the transplant recipient depends on preventing excessive vasoconstriction, usually with calcium channel blocking agents.

Renal allograft artery stenosis: results of medical treatment and intervention. A retrospective analysis

In a retrospective analysis of 1165 renal transplantations in our center, 65 cases of renal allograft artery stenosis were diagnosed angiographically (prevalence 5.5%). Hypertension was present in all cases; a bruit over the allograft and an increase in serum creatinine level were additional reasons for angiography. Shortly after diagnosis of the stenosis, two patients died and two others lost their grafts due to thrombosis. In 24 patients the decision was made not to correct the stenosis. One of these grafts was lost because the stenosis could not be corrected. Medical management of hypertension in these patients resulted in a decrease in diastolic blood pressure from 109 +/- 22 to 96 +/- 12 mm Hg (P < 0.01) 3 months after diagnosis with the use of almost twice as many antihypertensive drugs as at the time of diagnosis (P < 0.01). The stenosis was corrected if the angiography showed it to be so severe that it jeopardized renal allograft function or caused uncontrollable hypertension. Only three of nine percutaneous transluminal angioplasty (PTA) procedures resulted in a definitive correction of the stenosis. Surgical intervention was performed in 30 patients, including two patients whose PTAs had proved unsuccessful. Surgery led to graft loss due to thrombosis in 6 of 30 operations (20%), whereas restenosis occurred twice (7%). In three other cases (10%), the correction was not successful due to local anatomical variations or concomitant rejection.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocytosis in renal allograft recipients. Benefit of staggered venous erythropoietin measurements

Two adult renal allograft recipients experienced erythrocytosis--one in acute form--within 3 months of grafting. Involvement of well functioning transplanted kidneys was unlikely whereas staggered erythropoietin measurements detected a high gradient in front of venous remnant kidneys. Because of these results bilateral nephrectomy was performed, which cured polycythaemia. Multiple events leading to polycythaemia after renal transplantation are reviewed and diagnosis and therapeutic schedules are proposed.

Fosinopril prevents hyperfiltration and decreases proteinuria in post-transplant hypertensives

Hypertension and renal mass reduction induce glomerular hypertension (GH), hyperfiltration (HF) and renal injury. GH may contribute to allograft loss in post-transplant hypertensive patients (PT x HT). HF and GH may be evaluated by renal response to acute protein intake (API). Since ACE inhibition may prevent GH, the effects of fosinopril (Fos) were evaluated in 10 PT X HT on azathioprine and prednisone. Patients received 5 to 40 mg/day of Fos during 12 months. Baseline MAP (111.1 +/- 2.9 mm Hg) was significantly reduced by 10 to 12 mm Hg, rising to 114.7 +/- 2.7 mm Hg after Fos was administered. GFR (63.7 +/- 5.9 ml/min) decreased after 4 (48.1 +/- 4.6, P less than 0.05) and 12 months (50.7 +/- 4.6, P less than 0.05), rising to 59.4 +/- 5.6 after Fos was given. There was no GFR response to API before and after one month of Fos, however, a clear response became apparent at 4 (+ 27% P less than 0.05), and 12 months (+ 18%, P less than 0.05), disappearing after Fos discontinuation. Proteinuria (918.8 +/- 710.6 mg/d) decreased after 4 (72.3 +/- 21.6 mg/d, P less than 0.05) and 12 months, rising to 297.8 +/- 172.3 mg/day after therapy. GFR response to API in 22 controls and 17 uninephrectomized donors was 13 and 11%, respectively. Lack of response to API in PT x HT suggests HF and GH. Reduction of GFR, restoration of response to API and reduction of proteinuria, indicate that ACE inhibition with fosinopril ameliorates HF and GH. This effect may be beneficial in preventing hemodynamic-mediated allograft injury.

Medical and surgical complications of renal transplantation: diagnosis and management

Renal transplantation is a common modality of therapy in end-stage renal failure, but it has the potential of developing many complications, both surgical and medical in nature. In transplantation surgery, more than in any other type of surgery, prevention of these complications is essential. This includes attention to many details, including optimum organ salvage, preservation, implantation, and postoperative care. Although infection has decreased in frequency and severity with the advent of antiviral and antibacterial agents, prevention, early diagnosis, and suitable treatment with appropriate antibiotic(s) will be necessary to obtain desirable results and to reduce morbidity and mortality. It should be stressed that although careful attention to the patients and adjustment of the immunosuppressive regimen may mitigate much of the gastrointestinal, hematologic, and osteogenic complications, high incidence of cancer of the skin and mucous membrane continues.

Post-transplant hypertension in the rat: effects of captopril and native nephrectomy

In patients with well-functioning renal allografts, the presence of diseased native kidneys appears to be a common cause of elevated blood pressure. We evaluated the role of native kidneys in post-transplant hypertension using a rat model in which the confounding variables of rejection and immunosuppression could be eliminated. To produce disease in native kidneys. PVG rats were subjected to 5/6 nephrectomy. Four weeks following renal ablation, these hypertensive animals were transplanted with kidneys from syngeneic PVG donors. Four weeks later, the effects of captopril and native nephrectomy on blood pressure and renal hemodynamics were examined. Animals with remnant native kidneys which received non-rejecting renal isografts had sustained hypertension, elevated plasma renin levels and reduced transplant function. In these animals, administration of captopril reduced systemic blood pressure. Despite the reduction in blood pressure, PAH clearance by the transplanted kidney increased markedly while GFR rose modestly. Removal of the remnant native kidney also acutely lowered blood pressure. However, compared to captopril, native nephrectomy produced a more marked increase in GFR without significantly affecting renal blood flow. In this model of post-transplant hypertension in the rat, elevated blood pressure and reduced isograft function are mediated by the diseased native kidney, in part through the effects of angiotensin II. These data suggest that ACE inhibitors and native nephrectomy may have beneficial hemodynamic effects in patients with post-transplant hypertension caused by native kidneys.

Systemic hypertension associated with cyclosporine: a review

Use of the immunosuppressive agent cyclosporine has been associated with an increased incidence of hypertension. The incidence, onset, duration, and severity of the associated blood pressure elevation varies greatly depending on the therapeutic indication for cyclosporine use. This paper reviews the disparity in the reports of cyclosporine-associated hypertension and the factors evaluated for possible association. Possible mechanisms involved in the blood pressure elevation as well as treatment approaches that have been employed are discussed. Further research efforts are needed to clarify conflicting information regarding mechanisms, associated factors, and rational treatment.

Risk factors for accelerated atherosclerosis in renal transplant recipients

The factors responsible for atherosclerosis in renal transplant recipients are not known. In the present study, cardiovascular disease was investigated in 403 patients who received 464 kidney transplants during a 10-year period. Among those who had no clinical evidence of vascular disease at the time of transplantation, atherosclerotic complications developed in 15.8 percent during the post-transplant follow-up period (46.1 +/- 36.2 months). Pre- and post-transplant vascular diseases were closely linked. However, after taking pre-transplant vascular disease into account, multivariate analysis showed that a number of known risk factors (age, sex, diabetes, cigarette smoking, hypertension, and serum cholesterol) were independently associated with post-transplant vascular disease. In addition, the number of acute rejection episodes (all treated with high doses of corticosteroids) was also independently linked to vascular disease. These results suggest that an increased prevalence of known risk factors, and events linked to allograft rejection, explain the high incidence of cardiovascular disease in renal transplant recipients.