Variations in arterial blood pressure after kidney transplantation. Relation to renal function, plasma renin activity, and the dose of prednisone

Eye Lesions in Patients After One Year of Kidney Transplantation

Purpose

Determine the incidence of some eye lesions in kidney transplant patients after one year at Military Hospital 103 and comment on related factors.

Patients and Methods

A cross-sectional study description of 111 kidney transplant patients (222 eyes) at Military Hospital 103. We assessed several eye lesions, including dry eyes, corneal conjunctival calcification, cataracts, and retinopathy.

Results

The rate of retinopathy was 84.7%, dry eye was 59.5%, cataract was 29.7%, and corneal conjunctival calcification was 24.8%, atrophy optic nerve was 9.9%, epiretinal membrane was 1.8%. Post-transplant influence factors associated with cataracts include the dose of prednisolone (OR= 1.6, p < 0.05) and post-transplant diabetes (OR=1.4, p < 0.05). The influence factor related to the atrophy of the optic nerve is systemic infection after transplantation (OR=2.4, p < 0.05).

Conclusion

Retinopathy accounted for the highest rate, followed by dry eye disease; cataracts ranked third; and finally, calcified corneal conjunctiva. Factors that affect cataracts are diabetes mellitus and prednisolone dose. Factors affecting optic nerve atrophy are infections after kidney transplantation.

New Approaches to Cardiovascular Disease and Its Management in Kidney Transplant Recipients

Cardiovascular events, including ischemic heart disease, heart failure, and arrhythmia, are common complications after kidney transplantation and continue to be leading causes of graft loss. Kidney transplant recipients have both traditional and transplant-specific risk factors for cardiovascular disease. In the general population, modification of cardiovascular risk factors is the best strategy to reduce cardiovascular events; however, studies evaluating the impact of risk modification strategies on cardiovascular outcomes among kidney transplant recipients are limited. Furthermore, there is only minimal guidance on appropriate cardiovascular screening and monitoring in this unique patient population. This review focuses on the limited scientific evidence that addresses cardiovascular events in kidney transplant recipients. Additionally, we focus on clinical management of specific cardiovascular entities that are more prevalent among kidney transplant recipients (ie, pulmonary hypertension, valvular diseases, diastolic dysfunction) and the use of newer evolving drug classes for treatment of heart failure within this cohort of patients. We note that there are no consensus documents describing optimal diagnostic, monitoring, or management strategies to reduce cardiovascular events after kidney transplantation; however, we outline quality initiatives and research recommendations for the assessment and management of cardiovascular-specific risk factors that could improve outcomes.

Unattended automated office blood pressure in living donor kidney transplant recipients

PURPOSE

Hypertension is common in kidney transplant recipients (KTRs). For the evaluation of blood pressure (BP), 24-h ambulatory BP measurements (ABPM) are considered superior to usual office measurements but are also resource demanding and troublesome to many patients. We therefore evaluated the use of unattended automated office BP (AOBP) during the first year following living donor kidney transplantation and compared AOBP with ABPM as obtained 12 months after transplantation.

MATERIALS AND METHODS

Data were retrieved from a cohort of 57 KTRs (mean age 45 ± 14 years, 75% males) who all received kidneys from living donors and had a good graft function (estimated glomerular filtration rate (eGFR) 52 ± 16 ml/min/1.73 m² at 12 months). Unattended AOBP was measured at each visit to the outpatient clinic using the BpTru® device, while ABPM was obtained by Spacelabs® equipment before and 12 months after transplantation.

RESULTS

AOBP remained stable from month 2 (130.2 ± 10.8/82.2 ± 7.8 mmHg) to month 12 (129.0 ± 12.8/83.1 ± 9.6 mmHg) post-transplantation. At 12 months follow-up, ambulatory daytime systolic BP was slightly higher than AOBP (132.7 ± 10.7 vs. 129.4 ± 12.2 mmHg, p = 0.04), while diastolic BP was similar (82.7 ± 7.7 vs. 82.0 ± 10.2 mmHg). Using Bland-Altman plots, 95% limits of agreements were -17.9 to 24.5 mmHg for systolic and -16.5 to 15.1 mmHg for diastolic BP. When considering a target BP of ≤130/<80 mmHg, 62% had sustained hypertension, 9% white coat hypertension and 11% masked hypertension. Using multiple linear regression analysis, only urine albumin-creatinine ratio tended to predict a higher systolic AOBP (p = 0.07).

CONCLUSION

In a cohort of stable living donor KTRs, mean values of unattended AOBP using BpTru® are comparable to daytime ABPM with a misclassification rate of approximately 20%.

Hypertension in the Pediatric Intensive Care Unit

Hypertension in the pediatric intensive care unit (PICU) is common and it contributes to the overall morbidity and mortality. Patients may present with hypertensive emergencies or hypertension can manifest itself later in PICU course. Although hypertension can be seen in most patients during hospitalization, patients with some specific diseases and conditions are more prone to hypertension. Hypertension should be recognized promptly and treated accordingly. Different pathophysiologic mechanisms can be responsible for the hypertension and management differs based on the underlying etiology. Any patient with a hypertensive emergency must be admitted to PICU, and treatment and diagnostic workup should be initiated immediately.

The renin-aldosterone system and renal hemodynamics in patients with posttransplant hypertension

Plasma renin concentration (PRC), plasma aldosterone concentration (PAC), renal plasma flow (RPF) and glomerular filtration rate (GFR) have been studied in 19 patients who had received a renal allotransplant. Group 1 consisted of 7 normotensive and group 2 of 12 hypertensive patients. Bilateral nephrectomy was performed in all patients; all were on a fixed daily sodium intake, and no antihypertensive agents were given. No significant differences were found between the groups in age, time after transplantation or dosages of prednisone. PRC and PAC were normal in all but one patient in group 1 and two in group 2. In these three patients a slight elevation of PRC was measured. After one hour in the erect position, a significant increase was measured in PAC, but not in PRC in both groups. After 6 days on a 10 mEq sodium diet, PRC and PAC increased significantly in both groups. After a further 6 days on the diet plus 150 mEq sodium daily, significant decreases in PRC and PAC were measured in both groups. No differences were detected in PRC or PAC between groups 1 and 2 either before or after the two dietary periods. RPF was significantly lower in the hypertensive group, whereas no significant difference was found in GFR between the groups. No significant relationship could be demonstrated between blood pressure (BP) and PRC or PAC, and PRC and PAC were not correlated to each other. RPF was significantly correlated to mean BP and PRC in the normotensive group but not in the hypertensive. It is concluded that PRC and PAC are normal in most patients with posttransplant hypertension, whereas the RPF is decreased. It is suggested that an abnormal regulation of renin secretion plays a role in the sustained elevation of BP after renal allotransplantation.

Plasma renin, plasma aldosterone and exchangeable sodium in normotensive and hypertensive kidney transplant recipients with and without transplant renal artery stenosis

Blood pressure (BP), plasma renin concentration (PRC), plasma aldosterone concentration (PAC) and exchangeable sodium (ES) were studied in 19 kidney recipients on different fixed levels of sodium intake after successful kidney transplantation. The following groups of kidney recipients were investigated: group 1: 7 normotensives, group 2:7 hypertensives without transplant renal artery stenosis (TRAS), group 3:5 hypertensives with angiographically verified TRAS. Hypertension in the recipients without TRAS (group 2) was characterized by a positive correlation between BP and ES and a normal response of PRC and PAC to a fixed low (10 mEQ/day) and high (150 mEq/day) sodium intake. In contrast, hypertension in the recipients with TRAS (group 3) was characterized by a normal or varyingly increased PRC on a liberal sodium intake and a reduced response of PRC to sodium restriction, whereas PAC did not differ from the other groups of recipients. In one recipient in group 3 who underwent surgical correction for TRAS, PRC and PAC decreased before operation during sodium restriction, but BP remained high until after operation, when it normalized simultaneously with a decrease in ES. The results indicate that sodium retention is involved in the pathogenesis of posttransplant hypertension and suggest that an increased activity of the renin--angiotensin system is counterbalanced by an accumulation of sodium in TRAS.

A case of renal artery stenosis after transplantation: can losartan be more accurate than captopril renography?

Hypertension is a common complication observed after renal transplantation. If the hypertension is of renovascular origin, transluminal angioplasty or surgery of the renal artery stenosis can lead help cure the hypertension. The blood pressure of a 31-year-old man who underwent renal transplantation 2 years earlier gradually increased. Arteriography showed stenosis (>80%) in the two branches of the renal artery. To help confirm the presence of renovascular hypertension, captopril renography was performed but showed no significant changes compared with baseline renography. Renography was performed again after losartan administration and showed impaired renal function. In this case, losartan renography was more useful than captopril in suggesting renovascular hypertension.

Secondary hypertension: evaluation and treatment

Most patients with hypertension in the United States have essential (primary) hypertension (95%), the cause of which is unknown. The remaining 5% of adults with hypertension have the secondary form of hypertension, the cause and pathophysiologic process of which are known. Internists and other primary care physicians refer to this as treatable or curable hypertension, because the hypertension can be managed or even controlled with medications. Similarly, the condition is called surgical hypertension by surgeons in the belief that once the cause is determined and identified, surgical intervention will result in cure of hypertension. Secondary causes of hypertension include renal parenchymal disease, renovascular diseases, coarctation of the aorta, Cushing's syndrome, primary hyperaldosteronism, pheochromocytoma, hyperthyroidism, and hyperparathyroidism. Occasionally included in this category are alcohol- and oral contraceptive-induced hypertension and hypothyroidism, but these conditions are not discussed herein. The evaluation of secondary hypertension is of interest and can bring together different facets of anatomy, physiology, pharmacology, and radiology in the medical and surgical treatment of these disorders. Despite enthusiasm that can be generated in the evaluation of these conditions, evaluation can be expensive and should not be conducted for all patients with hypertension. Features that aid in the diagnosis of secondary hypertension include the following: 1. Onset of hypertension before the age of 20 or after the age of 50 years. The presence of hypertension at a young age may suggest coarctation of the aorta, fibromuscular dysplasia, or an endocrine disorder. Hypertension found for the first time after the age of 50 years may suggest the presence of renovascular hypertension caused by atherosclerosis. 2. Markedly elevated blood pressure or hypertension with severe end-organ damage, as in grade III or IV retinopathy. These findings suggest the presence of renovascular hypertension or pheochromocytoma. 3. Specific body habitus and ancillary physical findings. For example, truncal obesity and purple striae occur with hypercortisolism, and exophthalmos is associated with hyperthyroidism. 4. Resistant or refractory hypertension (poor response to medical therapy usually necessitating use of more than three antihypertensive medications from three different classes). 5. Specific biochemical test that suggest the existence of certain disorders, such as hypercalcemia in hyperparathyroidism, hyperglycemia in Cushing's syndrome and pheochromocytoma, and unprovoked hypokalemia with renin-producing tumors, primary hyperaldosteronism, or renin-mediated renovascular hypertension. 6. Other characteristics that may suggest secondary hypertension such as abdominal diastolic bruits (renovascular hypertension), decreased femoral pulses (coarctation of the aorta), or bitemporal hemianopias (Cushing's disease). A combination of a good history and physical examination, astute observation, and accurate interpretation of available data usually are helpful in the diagnosis of a specific causation.

Successful steroid withdrawal half a year after kidney transplantation

We report two kidney transplant recipients with successful steroid withdrawal. They are living related donor transplant recipients. The first patient, a 37-year-old female, received the kidney from her HLA identical father. The second patient, a 44-year-old man, received the kidney from his HLA 1 haploidentical brother. Both patients were maintained on triple immunosuppressive drug therapy prior to withdrawal of steroid and subsequently were maintained on cyclosporine and azathioprine or mizoribine. Acute rejection occurred within the first 1 month and was treated with steroid bolus therapy successfully in both cases. The time of steroid withdrawal after transplantation was 6.5 months in the first patient and 5 months in the second patient. After steroid withdrawal their graft function remained stable and the graft specimens obtained by biopsy 8 months after withdrawal showed no signs of rejection; no side effects of steroid appeared. These results suggest that steroid withdrawal half a year after transplantation can be accomplished without jeopardizing graft function in selected living related donor transplant recipients.

[Change in renin activity and blood pressure in the dog autologous kidney transplant model with modified HTK solution]

Investigations of changes in activity of renin and blood pressure after reperfusion of the kidney transplant using HTK solution were carried out by means of an autologous, heterotopic model of kidney transplantation applied to dogs. Duration of cold ischemia was 48 h. According to variations in the composition of the HTK perfusion solution three test groups were set up. During the first 20 min after recirculation in each test group the renal venous and arterial renin activities were measured. Parallel to renin activity, the arterial blood pressure was recorded. During the first few minutes following recirculation of the kidney transplant the renin levels in the venous blood of the kidney were higher in test group 1 (HTK solution, perfusion height 120 cm) than in either of the other two, showing a median maximal increase of 195 ng/ml.h. In test group 2 the maximal venous renin concentration fell to 145 ng/ml.h, while graphs take a more uniform course. Test group 3 (HTK/tryptophan) differed from the others in having further improved renin values. After the 7.5 min of observation normal venous renin concentrations were measured following earlier values for maximal increase between 23.1 ng/ml.h and 120 ng/ml.h (median 61.5 ng/ml.h). The best reperfusion of the kidney was observed in the tryptophan group, albeit without any recognizable positive effects on the other renal functions. Initially low renin values do not necessarily correlate with a smooth postoperative renal function and vice versa. Initial renin values cannot provide a secure basis for predicting instant as well as long-term postoperative functions.(ABSTRACT TRUNCATED AT 250 WORDS)

Oxalate nephrosis and renal sclerosis after renal transplantation in a cat

A 10-year-old castrated domestic shorthair cat received two renal allografts, 14 days apart, for the treatment of chronic renal failure. Oxalate nephrosis developed in both allografts, and they became nonfunctional. During the transplantation period, the cat was not exposed to exogenous sources of oxalate, and there was no evidence of primary type 2 hyperoxaluria before surgery. Urologic surgery, in particular renal transplantation, has been identified as a factor that can precipitate renal failure in human patients with decompensated renal function and hyperoxaluria. If hyperoxaluria was present before surgery in this cat, it was most likely caused by increased absorption or decreased metabolism of dietary oxalate.

Causes of renal allograft loss. Progress in the 1980s, challenges for the 1990s

A variety of refinements in the care of kidney transplant recipients have been instituted over the past decade. The authors studied the overall impact of these refinements on kidney allograft losses at a single institution. To do this they compared the causes and rates of graft loss for primary kidney transplants in the 1970s (January 1, 1970 to December 31, 1979; n = 1012; 657 nondiabetics, 355 diabetics; 617 living donors, 395 cadaver donors) versus the 1980s (January 1, 1980 to December 31, 1989; n = 1,384; 756 nondiabetics, 628 diabetics; 740 living donors, 644 cadaver donors). Overall patient survival improved significantly, with rates at 1, 5, and 10 years of 94%, 84%, and 68% for the 1980s, compared with 86%, 69%, and 57% for the 1970s (p less than 0.001). Actuarial graft survival also improved significantly, with rates at 1, 5, and 10 years of 86%, 71%, and 52% for the 1980s, compared with 73%, 58%, and 43% for the 1970s (p less than 0.001). This improvement occurred even though there were proportionately more cadaver donors and diabetic recipients in the 1980s. For both decades combined, 24% of the lost grafts were due to chronic rejection, 18% to cardiovascular causes of death with function, 13% to infectious causes of death with function, and 11% to acute rejection. The overall gain in graft survival rates in the 1980s was principally due to fewer cases of acute rejection and fewer infectious deaths. Improvement in graft survival due to the two leading causes--chronic rejection and cardiovascular causes of death--was relatively small, if any. These data indicate that future kidney transplantation research should emphasize prevention of chronic rejection and cardiovascular death.

Percutaneous transluminal angioplasty for transplant renal artery stenosis in children

Severe hypertension developed secondary to renal artery stenosis in 11 of 229 children who received a renal allograft. Renal artery stenosis was suspected because of de novo development of hypertension or exacerbation of pre-existing hypertension, which was detected 1 to 24 months after transplantation. Selective renal angiography was performed 2 to 74 months after transplantation (mean 13 months). Follow-up was 1 to 8 years (mean 2.5 years). The stenosis involved the anastomosis in 5 patients and was distal to the anastomosis in 6. One graft had an arteriovenous malformation. Seven grafts were suitable for vessel dilation; percutaneous transluminal angioplasty was partially successful in 4 cases in which the stenosis occurred at the anastomosis. The remaining patients were treated with medical therapy alone and the grafts were not lost. Our findings suggest that strictures distal to the anastomosis rarely are amenable to percutaneous transluminal angioplasty and should be treated medically whenever possible. Strictures at the anastomosis respond to vessel dilation but antihypertensive medication also often is required. An operation should be reserved for patients who do not respond to these measures.

Role of the kidney in the pathogenesis of primary hypertension

Primary hypertension in animals and humans probably represents several different pathophysiological states rather than being a uniform nosological entity. Among other factors, renal mechanisms may be primarily and secondarily involved. The availability of genetically homologous animal models for hypertension has greatly promoted studies on the etiology and pathogenesis of high blood pressure disease. In particular, renal transplantation studies between genetically hypertensive and normotensive rats from three different models have provided strong evidence for a primary role of the kidney in genetic hypertension. Other factors, such as vascular, neural, and humoral mechanisms have also been shown to be involved and may be particularly effective in increasing blood pressure, when they act through the kidney. Several functional and biochemical differences have been identified between kidneys from genetically hypertensive and normotensive animals. However, the relative contribution of each of these factors to the development of primary hypertension remains to be determined. Evidence from studies on human renal graft recipients also indicates that, among other factors, the kidney plays an important role in the development of primary hypertension in humans.

[Duplex sonography in the diagnosis of renal artery stenoses following allogenic kidney transplantation]

Posttransplant renal artery stenosis (TRAS) as a cause of secondary hypertension is reported with an incidence of 1 to 10%. Early diagnosis of TRAS should be made by non-nephrotoxic and non-invasive means to lower the risk of hypertension. One to 66 months after kidney transplantation 335 patients underwent Duplex-scanning, 38 of cases for clinical tentative diagnosis of TRAS. Parameters for clinical diagnosis of TRAS were diastolic hypertension greater than 100 mm Hg with resistance to therapy (A), an abdominal bruit over the transplant (B), disturbance of renal function (serum-creatinine greater than 2 mg/dl) (C). Admission to study followed the parameter-combination A + B. A + C, B + C. Rejection crisis was excluded in 18/38 cases by fine needle biopsy, cyclosporine over-dosage was negative in 38/38 cases, 20/38 cases had normal renal function. Duplex-/Doppler-ultrasound criteria for TRAS were systolic peak velocity greater than 100 cm/s-1 and broadening of the diastolic frequency spectra with a smooth decline in diastole to an elevated diastolic level. In 32/38 cases (84.2%, n = 38) diagnosis of TRAS was made by duplex-scanning, angiography confirmed the result in 30/32 cases (93.75%, n = 32); sensitivity was 88.2% with a specificity of 66.6%. Duplex-scanning as a primary diagnostic means for TRAS seems a promising method compared to e.g. radionuclide imaging or angiography. Duplex-scanning is a non-nephrotoxic and non-invasive procedure repeatable at any time with only few preliminary conditions.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypertension is not a complication in cyclosporine-A monotherapy

The course of blood pressure and antihypertensive treatment (AHT) was studied in 27 renal transplant recipients immunosuppressed with cyclosporine-A (CyA) as monotherapy. At the time of transplantation 13 patients received AHT and 14 were normotensive. The final outcome of transplantation and CyA immunosuppression was 19 patients without AHT, 4 with reduced AHT and 3 with unchanged doses of AHT, while in 1 case a de novo mild hypertension necessitated diuretic treatment.

Early and late hemodynamic evaluation after cardiac transplantation: a study of 28 cases

Right heart catheterization was performed in 28 patients 1 week and 6 to 24 months after orthotopic cardiac transplantation. All patients were receiving cyclosporine and methylprednisolone orally. At early catheterization, right heart pressures as well as pulmonary capillary wedge pressure still remained above normal values in the majority of patients. Systemic arterial hypertension was already present in 29% of the patients and cardiac index was usually in the normal range, without any inotropic support. Results of late catheterization showed continuing improvement with return of right heart pressures to normal values in most but not all patients. Systemic arterial hypertension was noted in nearly all patients and is likely to be the result of hypervolemia secondary to cyclosporine-induced sodium retention. The increase in cardiac index, which was above normal values in 39% of the patients, was also consistent with hypervolemia in the setting of cardiac denervation. Thus, cardiac function at rest is satisfactory at short- and long-term assessment after cardiac transplantation, but the development and persistence of systemic arterial hypertension associated with cyclosporine use are a matter of concern in such patients.

Influence of cyclosporine on posttransplant blood pressure response

The suggestion that hypertension is more prevalent in renal allograft recipients receiving cyclosporine (CyA), particularly those displaying nephrotoxicity, was tested by reviewing 200 patients' courses, including 92 cadaver (CAD) and 58 living-related (LRD) transplants using CyA and prednisone immunosuppression, and 19 CAD and 31 LRD transplants using azathioprine (Aza) and prednisone, all of whom had at least 1 year posttransplant complete outpatient follow-up. Both groups had a mean age of 33 years with a similar distribution of renal failure etiologies. Renal function was significantly impaired in the CyA group at all intervals (P less than .001, t test). The prevalence of hypertension was higher in the CyA group at all intervals, becoming significant at 12 (P less than .01) and 24 (P less than .05) months following transplantation (chi 2). While there was only a significant difference in mean diastolic BP at 12 months (P less than .05, t test), the mean number of antihypertensive and/or diuretic medications was significantly greater in the CyA group at 1 and 6 months (P less than .001) and at 12 months (P less than .01). By 24 months, the mean number of all antihypertensive and/or diuretic medications was no longer significantly different. However, the antihypertensive and diuretic requirements of the CyA group diminished with time, suggesting that the hypertension is not progressive if the CyA serum trough levels are maintained in the nontoxic range (less than 200 ng/mL).

Post-renal-transplant hypertension. Urine volume, free water clearance and plasma concentrations of arginine vasopressin, angiotensin II and aldosterone before and after oral water loading in hypertensive and normotensive renal transplant recipients

Urine volume (V), free water clearance (CH2O) and plasma concentrations of arginine vasopressin (AVP), angiotensin II (A II) and aldosterone (Aldo) were determined before and three times during the first 5 h after an oral water load of 20 ml/kg body wt in 19 patients with post-renal-transplant hypertension (group I), in 13 normotensive renal transplant recipients (group II) and in 20 control subjects (group III). Both V and CH2O increased significantly in all groups, but considerably less in groups I and II than in group III. When CH2O was related to glomerular filtration rate no differences existed between patients and control subjects. Basal AVP was the same in groups I (3.3 pmol/l, median) and II (3.0 pmol/l), but significantly (p less than 0.01) higher than in group III (1.9 pmol/l). Basal A II was significantly (p less than 0.01) elevated in group I (18 pmol/l) when compared to both groups II (10 pmol/l) and III (11 pmol/l), and the level was independent of the presence of native kidneys. Basal Aldo was the same in all groups. During loading, AVP was reduced in all groups, A II was almost unchanged, and Aldo was increased in groups I and II and reduced in group III depending on alterations in serum potassium. Thus urinary diluting ability is reduced in renal transplant recipients due to a reduced glomerular filtration rate. The enhanced A II in hypertensive renal transplant recipients gives further evidence for the point of view that hypertension is angiotensin-dependent in most of these patients.

The contrasting effects of cyclosporin-A and azathioprine on arterial blood pressure and renal function following cardiac transplantation

The effects of cyclosporin-A and azathioprine on the postoperative development of systemic hypertension and renal dysfunction in patients undergoing cardiac transplantation were compared retrospectively in 18 patients receiving cyclosporin-A and in 12 patients receiving azathioprine. Twelve months postoperatively, the average mean blood pressure was 116 +/- 13 mm Hg and 98 +/- 7.5 mm Hg; the average preoperative serum creatinine was 1.2 +/- 0.3 mg% and 1.5 +/- 0.3 mg%; and the postoperative serum creatinine was 2.2 +/- 0.8 mg% and 1.1 +/- 0.2 mg% (P less than 0.0001) in the cyclosporin-A-and azathioprine-treated groups respectively. Hemodynamic studies were done to characterize the de novo postoperative hypertension developing in the cyclosporin-A group. The pre- and postoperative cardiac output was 3.7 and 4.91/min, respectively (P less than 0.01). The pre- and postoperative systemic vascular resistance was 1707 and 1941 dynes sec X cm-5, respectively (P greater than 0.2). Peripheral renin activity and 24-hour urinary catecholamine excretion were not elevated. The mechanism of the hypertension developing in cyclosporin-A-treated patients is unknown, but is associated with normalization of cardiac output, an abnormally elevated systemic vascular resistance, and modest impairment of renal function. These findings are in marked contrast to azathioprine-treated patients, in whom postoperative hypertension and renal dysfunction do not occur. These observations implicate cyclosporin-A as the major contributing factor in the development of hypertension and renal dysfunction.

Hypertension and kidney transplantation

Patients with kidney transplants are often hypertensive. Investigators have described the characteristics of this hypertension in man. Moreover, the hypertension of kidney transplant patients has a higher probability of being responsive to surgical intervention than does hypertension in the general population. Yet the mechanisms of the many varieties of posttransplantation hypertension are not known in detail. Detailed studies that would best be done in animal models are rare. Both medical and surgical management of this transplantation-associated complication needs further study.

Interventional radiologic procedures in the management of the renal transplant patient

Interventional radiologic procedures have become an important adjunct to the management of the renal transplant patient. Numerous problems can be dealt with, and in our experience these have included the diagnosis and treatment of ureteric obstruction, dilatation of renal artery stenoses, drainage of abscesses, hematomas and lymphoceles, management of complications of pancreatitis and treatment of bleeding due to fistulas and pseudoaneurysms.

Mechanisms of posttransplant hypertension

Posttransplant hypertension is an important risk factor for cardiovascular mortality and graft function. We performed metabolic studies in 35 hypertensive patients with well-maintained graft function on maintenance immunosuppressive drugs and in 17 normotensive control transplant recipients. The group of hypertensive recipients were characterized by increased peripheral plasma renin activity, lack of change in blood pressure in response to salt loading and restriction, and by increased peripheral and renal resistance. In contrast, on the same protocol in a group of patients with essential hypertension, blood pressure fell significantly on a low-salt intake. Peripheral resistance in hypertensive transplant recipients fell in response to saline loading, in contrast to the effects in normotensive transplant recipients. Hypertensive patients with retained native kidneys as compared to those who had these removed prior to transplant, but were still hypertensive, differed only with regard to reduced renal plasma flow in the former group. These data are consistent with a predominantly renin-dependent hypertension in these renal transplant recipients. When bilateral nephrectomy or repair of graft renal artery stenosis is being considered, response to captopril may offer a means of selection; acute renal failure on captopril suggests functionally significant renal artery stenosis.

Renal artery stenosis in transplant patients

Although hypertension appears not infrequently among recipients of kidney transplants, renal artery stenosis is relatively rare as a causative factor. A 23-year experience of patients receiving kidney grafts at the Brigham and Women's Hospital was reviewed to ascertain the incidence of renal artery stenosis and its surgical management. Risk factors leading to the condition and selection of patients for operation are emphasized. The incidence of arterial stenosis severe enough to require operation was 2.7% of 914 kidney transplants; the overall incidence in these patients is unknown, although operated patients comprise about one-half of those undergoing arteriography to diagnose hypertension. The mean time for development of the condition was 21.4 months from date of engraftment. A successful outcome as measured by fall in blood pressure and/or serum creatinine was achieved in 14 of 21 patients (67%) in whom surgical repair of the effected artery was undertaken. Reparative surgery was unsuccessful in seven patients, although hypertension was improved in one of these individuals following transplant nephrectomy. Surgery was never undertaken in four patients because of chronic rejection noted on biopsy. There was no mortality. Operative repair should be offered to patients with renal artery stenosis leading to unmanageable hypertension or renal dysfunction, but withheld from those with documented chronic rejection regardless of major arterial compromise.

Remission of essential hypertension after renal transplantation

Six patients in whom "essential hypertension" led to nephrosclerosis and kidney failure received kidney transplants from normotensive donors. After an average follow-up of 4.5 years, all were normotensive and had evidence of reversal of hypertensive damage to the heart and retinal vessels. These six patients, all of whom were black, and six control subjects matched for age, sex, and race were admitted to the General Clinical Research Center for 11 days for observation of their blood pressure and their responses to salt deprivation and salt loading. Mean arterial pressure (+/- S.E.M.) among the patients who had previously had essential hypertension was similar to that of the normal controls (92 +/- 1.9 vs. 94 +/- 3.9; P not significant), and both groups had similar responses to salt deprivation and salt loading. Thus, essential hypertension in human beings is shown to be similar to the hypertension seen in spontaneously hypertensive rats in that both can be corrected by transplantation of a kidney from a normotensive donor. This observation supports the concept of the primary of the kidney in causing essential hypertension.

Screening for transplant renal artery stenosis in hypertensive recipients using digital subtraction angiography

Digital subtraction angiography was used in 10 renal allograft recipients with sustained hypertension after transplantation to detect transplant renal artery stenosis. Recipients with end-to-end vascular anastomoses were visualized adequately in the anteroposterior projection. Two cases of transplant renal artery stenosis were identified by digital subtraction angiography and then verified by catheter angiography. Patients with end-to-side vascular anastomoses may require additional oblique projections. Digital subtraction angiography is a safe, noninvasive and cost-effective screening procedure to diagnose transplant renal artery stenosis in most recipients. Catheter angiography can be applied more selectively to those recipients with stenosis observed by digital subtraction angiography or when more detailed imaging is required.

Embolization and angioplasty to relieve malignant hypertension and azotemia in a renal transplant patient

The case of a 23-year-old patient with malignant hypertension following a renal transplant illustrates the successful treatment of the hypertension with embolization of the native kidneys. Azotemia followed and was successfully treated with percutaneous transluminal angioplasty of high-grade stenosis at the anastomotic site of the allograft. Malignant hypertension redeveloped with the recanalization of the embolized native kidneys. This was successfully treated with contrast ablation.

Urinary kallikrein excretion after renal transplantation: relationship to hypertension, graft source, and renal function

The role of the renal kallikrein-kinin system in the pathogenesis of hypertension and various forms of renal dysfunction after human renal transplantation has been assessed by measurement of urinary kallikrein activity in 41 renal transplant recipients. The urinary tosyl arginine methyl esterase assay was used. The urinary kallikrein in these patients appeared to originate from the transplanted kidney and not their own diseased kidneys. Twenty-three recipients had hypertension (mean blood pressure 156 +/- 3/98 +/- 2 mm Hg) and excreted less kallikrein (4.0 +/- 1.2 versus 12.5 +/- 4.0 esterase units [EU] per 24 hours, p less than 0.05) than their 18 normotensive counterparts (mean blood pressure 132 +/- 2/77 +/- 1 mm Hg, both p less than 0.01). Subjects with renal complications of transplantation (acute tubular necrosis [ATN], nine patients, or acute rejection [AR], eight patients) also excreted less kallikrein than the 28 subjects without such complications (3.4 +/- 0.9 versus 10.3 +/- 2.7 EU/24 hours, p less than 0.02). Among those with acute renal complications, subjects with ATN excreted less kallikrein than those with AR (1.3 +/- 0.3 versus 5.7 +/- 1.7 EU/24 hours, p less than 0.02). Cadaver graft recipients excreted less kallikrein than living related donor graft recipients (2.1 +/- 0.4 versus 13.0 +/- 3.5 EU/24 hours, p less than 0.01), perhaps reflecting their higher blood pressures (mean systolic pressure 151 +/- 3 versus 140 +/- 3 mm Hg, p less than 0.04), relatively impaired renal function (creatinine clearance values 42 +/- 8 versus 62 +/- 5 ml/min, p less than 0.04), and higher incidence of ATN (nine cases versus none). The kallikrein-kinin system may be involved in the pathogenesis of hypertension and some forms of renal dysfunction after renal transplantation.

The improving utility of renal transplantation in the management of end-stage renal disease

The results achieved by treating patients with end-stage renal failure with allotransplantation have improved dramatically since the 1950s when immunosuppression was induced by total body irradiation and there was a lack of HLA typing. Although long-term hemodialysis offers prolonged survival and partial rehabilitation for many individuals with end-stage renal disease, the technique is inconvenient and time consuming. Patients are restricted by necessary proximity to the machine, dietary limitations, potential failure of access sites, and complications of various organ systems. Despite the availability of dialysis and the federal funds to partially pay for treatment, long-term dialysis still remains a costly process for the individual in need of care. During the same period when dialysis techniques improved and became widely available, transplantation of the human kidney became an established and justified treatment for some patients with end-stage renal disease. Those with successful kidney allografts may achieve remarkable recovery and are often able to return to normal lives. One of the more striking improvements in the results of renal transplantation in recent years had been the decline in morbidity and mortality. Mortality by the end of the first year after transplantation during which time most deaths occur, is currently less than 5 percent in a number of major medical units. In part, this decline represents a change in philosophy by transplant teams, who now tend to decrease immunosuppression and sacrifice the kidney rather than the patient in instances of inexorable rejection. In addition, declining mortality is directly attributable to improved methods of preventing, discovering, and treating patients with potential or real infections. More recently, in some centers, the rate of successful engraftment has shown gratifying improvement due to refinements in tissue typing, improved cross matching, new immunosuppressive therapies, and pretransplant conditioning with blood products. These recent improvements are the primary focus of this review. Unfortunately, until very recently, rates of functional survival of allografts have not been satisfactory.

Peripheral plasma renin activity (PRA) in recipients with allograft artery stenosis; its diagnostic value in acute stage hypertension

Peripheral PRA was examined in 11 patients with graft artery stenosis after the onset and throughout the course of hypertension. In the acute stage PRA was elevated in 9 patients and decreased to normal in the later stage of hypertension in all but 1 patient with malignant hypertension. The findings suggest that the determination of peripheral PRA is helpful in diagnosing graft artery stenosis only in the acute stage of hypertension, but it has no unequivocal value to the prognosis of hypertension or indication for operation.

Increased plasma levels of 6-oxo-prostaglandin F1 alpha, a stable metabolite of prostacyclin, in acute kidney transplant rejection

In 30 patients after kidney transplantation, 6-oxo-PGF1 alpha was examined in unextracted plasma by a specific radioimmunoassay. The material was divided into three groups. Patients with acute transplant rejection showing the highest 6-oxo-PGF1 alpha levels, patients with delayed transplant rejection having significantly lower plasma values and a third group of patients with stable transplant function. In these patients the plasma 6-oxo-PGF1 alpha-values were below the lower limit of detection (70 pg/ml). The enhanced 6-oxo-PGF1 alpha during rejection crisis could be interpreted as a self protection mechanism of vascular tissue which is, however, not sufficient in many cases, to prevent the irreversible rejection of the transplant.

Episodic hypertension caused by recurrent renal artery lesions following transplantation: a case report

A kidney transplant patient developed recurrent hypertension on two successive occasions associated with lesions of the renal artery. The first episode of hypertension was caused by renal artery stenosis and was surgically corrected; the second was caused by a sizable pseudoaneurysm at the site of arterial anastomosis which was resected, and arterial continuity was successfully re-established.

The patterns of peripheral plasma renin concentration in the early post-renal-transplant period

Serial determinations of peripheral plasma renin concentration (PRC) were performed in 11 kidney transplant recipients during the early post-transplant period. In 5 recipients with late onset of graft function, PRC values were increased during the anuric phase and, subsequently, PRC values declined in every during restoration of graft function. In 4 recipients with an acute renal allograft reaction, PRC values were increased at the onset of the allograft reaction in 3 with hypertension whereas PRC values were normal in one normotensive recipient. Subsequently, PRC normalized in the hypertensives coincident with increasing body weights. In 2 recipients with an uncomplicated course and with a normal graft function immediately after transplantation and throughout the study period, PRC values were constantly normal. The results indicate that acute anuria in the early phase after kidney transplantation is associated with an increased release of renin. The results also suggest that an increased activity of the renin-angiotensin system may be counterbalanced by sodium and fluid retention in hypertension following an acute renal allograft reaction.

Role of the renin-angiotensin system in post-transplantation hypertension in patients with multiple kidneys

To define the role of the renin-angiotensin system in post-transplantation hypertension we studied 12 hypertensive recipients of renal transplants. The patients received saralasin acetate, an angiotensin II antagonist, while on a normal sodium diet and again after seven days of sodium restriction. In six patients with only one kidney, saralasin did not lower blood pressure on either diet; salt depletion did not lower systolic or diastolic blood pressures. In six patients with more than one kidney, salt depletion also did not lower blood pressure; however, salt depletion plus saralasin lowered their systolic pressures from a mean (+/- S.E.M.) of 146 +/- 9 to 128 +/- 8 mm Hg, and mean diastolic pressures fell from 103 +/- 5 to 89 +/- 5 (P less than 0.001). In four of five patients renal-vein renin activity was greater in one or more host kidneys than in the transplant kidney (or kidneys). Although pre-transplant blood pressure was the same in both groups, post-transplantation hypertension is more likely to be angiotensin II-dependent in patients with more than one kidney.

Plasma renin activity following renal transplantation

Plasma renin activity (PRA) was studied serially for up to 21 days following transplantation in thirteen patients receiving renal allografts. PRA was measured during fasting and recumvency and its relationship to renal function, diuretic administration, plasma sodium, allograft rejection and blood pressure was examined. PRA fell steadily as renal function improved and plasma sodium rose following transplantation and when rejection episodes were excluded an inverse relationship between PRA and renal function could be seen. It is not possible to say whether the changes in PRA and function are causally related or whether changes in plasma sodium alone account for the observed changes in PRA. Some rejection episodes were accompanied by an increase in PRA, but this was not sufficiently consistent to be of value in the diagnosis of rejection. PRA also increased in relation to frusemide-induced fluid loss. There was no relationship in these patients between PRA and blood pressure.

Studies of renin-aldosterone axis in stable normotensive and hypertensive renal allograft recipients

Functional aspects of the renin-aldosterone axis were investigated in long-term normotensive and hypertensive renal allograft recipients. Unstimulated plasma renin and aldosterone levels were within control range in all patients and rose significantly in response to sodium depletion. However, no difference in the stimulated renin and aldosterone values between normotensive and hypertensive patients was noted. Baseline aldosterone secretory rates were elevated in all patients, but were higher in hypertensive patients than in normotensive patients. In both groups sodium depletion failed to augment this already elevated aldosterone secretion rate. Possibly, changes in the body pool and/or metabolic clearance rate of aldosterone account for elevations in plasma levels despite a relatively fixed secretory rate, though the role played by the lack of normal innervation of the kidneys cannot be ignored. It is unknown whether these observations may be causal or affected by other presently unknown or unmonitored factors. This in part may reflect unfolding problems in the understanding of nonrenal transplant hypertension.

Renal artery stenosis in hypertensive renal transplant recipients

Reconstruction of a stenotic renal artery was done on 5 hypertensive renal transplant recipients, all of whom had deterioration of renal function when the stenosis was detected. After reconstruction renal function improved in 4 of the patients. The blood pressure was easier to control in all 5 patients, with 3 becoming normotensive. A high preoperative plasma renin activity returned to normal postoperatively in 4 patients. No recurrences were observed after a followup of more than a year.