Hypertension in renal transplant recipients

Sleep-Disordered Breathing and 24-Hour Ambulatory Blood Pressure Monitoring in Renal Transplant Patients: Longitudinal Study

Background Sleep-disordered breathing (SDB) is considered a strong risk factor for hypertension in the general population. This disturbance is common in end-stage kidney disease patients on long-term hemodialysis and improves early on after renal transplantation. Whether SDB may be a risk factor for hypertension in renal transplant patients is unclear. Methods and Results We investigated the long-term evolution of simultaneous polysomnographic and 24-hour ambulatory blood pressure (BP) monitoring recordings in a cohort of 221 renal transplant patients. Overall, 404 paired recordings were made over a median follow-up of 35 months. A longitudinal data analysis was performed by the mixed linear model. The apnea-hypopnea index increased from a median baseline value of 1.8 (interquartile range, 0.6-5.0) to a median final value of 3.6 (interquartile range, 1.7-10.4; P=0.009). Repeated categorical measurements of the apnea-hypopnea index were directly associated with simultaneous 24-hour, daytime, and nighttime systolic ambulatory BP monitoring (adjusted analyses; P ranging from 0.002-0.01). In a sensitivity analysis restricted to 139 patients with at least 2 visits, 24-hour, daytime, and nighttime systolic BP significantly increased across visits (P<0.05) in patients with worsening SDB (n=40), whereas the same BP metrics did not change in patients (n=99) with stable apnea-hypopnea index. Conclusions In renal transplant patients, worsening SDB associates with a parallel increase in average 24-hour, daytime, and nighttime systolic BP. These data are compatible with the hypothesis that the link between SDB and hypertension is causal in nature. Clinical trials are, however, needed to definitively test this hypothesis.

Approach and Management of Hypertension After Kidney Transplantation

Hypertension is one of the most common cardiovascular co-morbidities after successful kidney transplantation. It commonly occurs in patients with other metabolic diseases, such as diabetes mellitus, hyperlipidemia, and obesity. The pathogenesis of post-transplant hypertension is complex and is a result of the interplay between immunological and non-immunological factors. Post-transplant hypertension can be divided into immediate, early, and late post-transplant periods. This classification can help clinicians determine the etiology and provide the appropriate management for these complex patients. Volume overload from intravenous fluid administration is common during the immediate post-transplant period and commonly contributes to hypertension seen early after transplantation. Immunosuppressive medications and donor kidneys are associated with post-transplant hypertension occurring at any time point after transplantation. Transplant renal artery stenosis (TRAS) and obstructive sleep apnea (OSA) are recognized but common and treatable causes of resistant hypertension post-transplantation. During late post-transplant period, chronic renal allograft dysfunction becomes an additional cause of hypertension. As these patients develop more substantial chronic kidney disease affecting their allografts, fibroblast growth factor 23 (FGF23) increases and is associated with increased cardiovascular and all-cause mortality in kidney transplant recipients. The exact relationship between increased FGF23 and post-transplant hypertension remains poorly understood. Blood pressure (BP) targets and management involve both non-pharmacologic and pharmacologic treatment and should be individualized. Until strong evidence in the kidney transplant population exists, a BP of <130/80 mmHg is a reasonable target. Similar to complete renal denervation in non-transplant patients, bilateral native nephrectomy is another treatment option for resistant post-transplant hypertension. Native renal denervation offers promising outcomes for controlling resistant hypertension with no significant procedure-related complications. This review addresses the epidemiology, pathogenesis, and specific etiologies of post-transplant hypertension including TRAS, calcineurin inhibitor effects, OSA, and failed native kidney. The cardiovascular and survival outcomes related to post-transplant hypertension and the utility of 24-h blood pressure monitoring will be briefly discussed. Antihypertensive medications and their mechanism of actions relevant to kidney transplantation will be highlighted. A summary of guidelines from different professional societies for BP targets and antihypertensive medications as well as non-pharmacological interventions, including bilateral native nephrectomy and native renal denervation, will be reviewed.

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.

Near-fatal, antihypertensive medication overdose due to post-operative gastric ileus

WHAT IS KNOWN AND OBJECTIVE

Post-operative gastrointestinal ileus is a common complication that can cause erratic absorption of oral pharmaceuticals.

CASE SUMMARY

This is a case of near-fatal, antihypertensive medication overdose due to gastric ileus in a 40-year-old patient following combined kidney-pancreas transplant. After being transitioned from intravenous to oral antihypertensive medications, the patient sustained pulseless bradycardia requiring resuscitative measures. Suspicion of accumulated medication bolus due to gastric ileus was confirmed by supratherapeutic serum labetalol measurement of 493 ng/mL (therapeutic range: 30-180 ng/mL).

WHAT IS NEW AND CONCLUSION

Judicious use of oral pharmaceuticals, particularly those with relatively narrow therapeutic ranges, is warranted in patients with post-operative ileus.

Kidney transplantation down-regulates expression of organic cation transporters, which translocate β-blockers and fluoroquinolones

Kidney transplanted patients are often treated with immunosuppressive, antihypertensive, and antibiotic drugs such as cyclosporine A (CsA), β-blockers, and fluoroquinolones, respectively. Organic cation transporters (OCT) expressed in the basolateral membrane of proximal tubules represent an important drug excretion route. In this work, the renal expression of OCT after syngeneic and allogeneic kidney transplantation in rats with or without CsA immunosuppression was studied. Moreover, the interactions of CsA, β-blockers (pindolol/atenolol), and fluoroquinolones (ofloxacin/norfloxacin) with rOCT1, rOCT2, hOCT1, and hOCT2 in stably transfected HEK293-cells were studied. Kidney transplantation was associated with reduced expression of rOCT1, while rOCT2 showed only reduced expression after allogeneic transplantation. All drugs interacted subtype- and species-dependently with OCT. However, only atenolol, pindolol, and ofloxacin were transported by hOCT2, the main OCT in human kidneys. While CsA is not an OCT substrate, it exerts a short-term effect on OCT activity, changing their affinity for some substrates. In conclusion, appropriate drug dosing in transplanted patients is difficult partly because OCT are down-regulated and because concomitant CsA treatment may influence the affinity of the transporters. Moreover, drug-drug competition at the transporter can also alter drug excretion rate.

Acute rejection modulates gene expression in the collecting duct

Kidney transplantation, especially when associated with acute rejection, leads to changes in the expression of many genes, including those encoding solute transporters and water channels. In a rat model of acute rejection after allogeneic renal transplantation, impaired renal function, increased urine volume, and increased fractional excretion of sodium were observed. Gene array analysis revealed that these findings were associated with significant downregulation of water channels (aquaporin-1, -2, -3, and -4) and transporters of sodium, glucose, urea, and other solutes. In addition, changes in expression of various receptors, kinases, and phosphatases that modulate the expression or activity of renal transport systems were observed. Syngeneic transplantation or treatment with cyclosporine A following allogeneic transplantation did not impair graft function but did lead to the downregulation of aquaporin-1, -3, and -4 and several solute transporters. However, expression of aquaporin-2 and the epithelial sodium channel did not change, suggesting that the downregulation of these transporters following allogeneic transplantation is rejection-dependent. In conclusion, changes in gene expression may explain the impaired handling of solute and water after allogeneic transplantation, especially during acute rejection. Treatment with cyclosporine A improves the regulation of solute and water by preventing the downregulation of aquaporin-2 and epithelial sodium channel, even though many other transporter genes remain downregulated.

Hypertension in the intensive care unit

PURPOSE OF REVIEW

The severity of hypertensive crises is determined by the presence of target organ damage rather than the level of blood pressure. Hypertensive urgencies with no signs of organ dysfunction can therefore be distinguished from hypertensive emergencies in which the presence of severe end-organ damage requires prompt therapy. Hypertensive emergencies include acute aortic dissection, hypertensive encephalopathy, acute myocardial ischaemia, severe pulmonary oedema, eclampsia, and acute renal failure.

RECENT DEVELOPMENTS

Malignant hypertension is a severe form of hypertensive emergency demanding special consideration because of the risks of permanent blindness and renal failure. Catecholamine excess and postoperative hypertension may also sometimes require urgent treatment. The management of patients with hypertensive emergencies must be ensured in an intensive care unit, and must include the parenteral administration of antihypertensive drugs and accurate blood pressure monitoring.

SUMMARY

Except for acute aortic dissection, the recommended goals of treatment are a reduction of mean arterial pressure by no more than 20% during the first few hours, because an abrupt fall in blood pressure in patients with preexisting hypertension may induce severe ischaemic injury in major organs as a result of the chronic adaptation of autoregulation mechanisms. Hypertension in the context of acute stroke should be treated only rarely and cautiously because of the presence of impaired autoregulation.

Acute rejection after rat renal transplantation leads to downregulation of NA+ and water channels in the collecting duct

Renal transplantation is associated with alterations of tubular functions and of the renin-angiotensin-aldosterone system. The underlying cellular and molecular mechanisms are unclear. We used an allogeneic rat renal transplantation model of acute rejection with and without immunosuppression by cyclosporine A (CsA) and a syngeneic model as control. Uninephrectomized Lewis or Lewis-Brown-Norway (LBN) rats received a kidney from LBN-rats. Renal transporters and receptors were analyzed by immunohistochemistry, semiquantitative RT-PCR and Western-blot analysis. Intracellular Na(+) was analyzed microfluorimetrically in isolated cortical collecting ducts. mRNA expression and function of the epithelial Na(+)-channel (ENaC) and mRNA and protein expression of the water-channel AQP2 were downregulated in transplanted kidneys undergoing rejection. Expression of the serum- and glucocorticoid-kinase (Sgk1) was decreased and that of the ubiquitin-protein ligase Nedd4-2 was increased. These changes were absent under CsA-therapy and in syngeneic model. Expression and function of the Na(+)-K(+)-ATPase, expression of the secretory K(+)-channel and of the mineralocorticoid receptor remained unchanged. Reduced ENaC function is likely due to decreased Sgk1- and increased Nedd4-2 mRNA expression leading to reduced ENaC expression in the membrane. These acute downregulations of ENaC and AQP2 may be triggered to reduce energy consumption in the distal nephron to protect the kidney immediately after transplantation.

Hypertension, antihypertensive agents and outcomes following renal transplantation

Hypertension is common following renal transplantation and adversely affects graft and patient survival. However, strategies for antihypertensive drug therapy and target blood pressure have not been clearly defined.

AIM

To assess the influence of achieved blood pressure and antihypertension drug therapy on graft and patient survival with the aim of identifying targets and event rates for future intervention studies.

METHODS

We undertook a longitudinal follow up study of 634 renal transplant patients. Patients were surveyed in December 1994 and followed up after 102 months. Blood pressure (BP) was determined from the mean of three clinic readings and antihypertensive drug therapy recorded.

RESULTS

Complete follow up data were available for analysis on 622 patients (57.2% male; mean age: 45.2 +/- 13.0 yr. There were 158 (25.4%) deaths and 115 (18.5%) death-censored graft failures. Lower systolic and diastolic blood pressure were associated with better graft survival in the Kaplan-Meier analysis. Univariate analysis showed serum creatinine (HR 1.012, p < 0.001), duration of renal replacement therapy (HR 0.946, p = 0.012), age (HR 0.979, p = 0.014) and pulse pressure (HR 1.017, p = 0.044) to be predictors of graft survival with serum creatinine and duration of renal replacement therapy as the only significant factors in the multivariate analysis. Lower systolic and pulse pressure were associated with better patient survival in the Kaplan-Meier analysis. Age (HR) 1.062, p < 0.0001), serum creatinine (HR 1.002, p = 0.021), diabetes (HR 3.371, p < 0.0001), and pulse pressure (HR 1.013, p = 0.036) were significant predictors of patient survival in the univariate and multivariate analysis. Patient survival was reduced with increasing number of antihypertensives (p < 0.05), as was graft survival (p < 0.05). Reduced patient and graft survival were seen in patients prescribed calcium channel antagonists (p < 0.01). There was no increased patient mortality in those patients on beta-blockers or angiotensin converting enzyme (ACE) inhibitors.

CONCLUSION

Hypertension is a risk factor, which remains despite the use of anti-hypertensives, for reduced patient and graft survival. The risk was not significant when blood pressure was entered together with serum creatinine in the multivariate analysis. Beta-blockers may have a beneficial effect on cardiovascular mortality, and ACE inhibitors a beneficial effect on both patient and graft survival. There is a pressing need for interventional studies to assess the impact of blood pressure targets on patient and graft survival and the effect of individual agents on these outcomes.

Posttransplant erythrocytosis

Posttransplant erythrocytosis (PTE) is defined as a persistently elevated hematocrit to a level greater than 51% after renal transplantation. It occurs in 10% to 15% of graft recipients and usually develops 8 to 24 months after engraftment. Spontaneous remission of established PTE is observed in one fourth of the patients within 2 years from onset, whereas in the remaining three fourths it persists for several years, only to remit after loss of renal function from rejection. Predisposing factors include male gender, retention of native kidneys, smoking, transplant renal artery stenosis, adequate erythropoiesis prior to transplantation, and rejection-free course with well-functioning renal graft. Just as in other forms of erythrocytosis, a substantial number (approximately 60%) of patients with PTE experience malaise, headache, plethora, lethargy, and dizziness. Thromboembolic events occur in 10% to 30% of the cases; 1% to 2% eventually die of associated complications. Posttransplant erythrocytosis results from the combined trophic effect of multiple and interrelated erythropoietic factors. Among them, endogenous erythropoietin appears to play the central role. Persistent erythropoietin secretion from the diseased and chronically ischemic native kidneys does not conform to the normal feedback regulation, thereby establishing a form of "tertiary hypererythropoietinemia." However, erythropoietin levels in most PTE patients still remain within the "normal range," indicating that erythrocytosis finally ensues by the contributory action of additional growth factors on erythroid progenitors, such as angiotensin II, androgens, and insulin-like growth factor 1 (IGF-1). Inactivation of the renin-angiotensin system (RAS) by an angiotensin-converting enzyme (ACE) inhibitor, or an angiotensin II type 1 AT1 receptor blocker represents the most effective, safe, and well-tolerated therapeutic modality.

Recipient hypertension potentiates chronic functional and structural injury of rat renal allografts

BACKGROUND

Systemic hypertension affects many allograft recipients, is an important risk factor for chronic graft dysfunction, and is linked to reduced graft survival. The condition may up-regulate the expression of inflammatory host cells and their products. These, in turn, may significantly injure vascular endothelium and other components of allografted kidneys.

METHODS

Lewis rats received orthotopic F344 renal allografts, a standard model of chronic rejection. Renovascular hypertension was produced by placing a silver clip (0.25 mm) on the renal artery of the retained contralateral native kidney 4 weeks after transplantation. Sham-clipped rats served as normotensive controls. Four recipient groups (Gp) were studied: Gp 1, rats with an allograft plus a clipped native kidney; Gp 2, those with an allograft and a sham-clipped native kidney; Gp 3, isografted animals with a clipped native kidney; and Gp 4, those bearing an isograft and a sham-clipped native kidney. Systolic blood pressure and proteinuria were measured every 2 weeks for 24 weeks. Grafts were assessed serially for morphologic and immunohistologic changes.

RESULTS

Systemic blood pressure rose to hypertensive levels in Gps 1 and 3 within a week of clipping but never increased in Gps 2 and 4. Proteinuria developed in hypertensive animals but remained at baseline in normotensive controls. Intimal thickening of allograft arteries progressed to luminal obliteration with extensive perivascular and interstitial fibrosis by 24 weeks. In contrast, vascular changes in isografts of hypertensive hosts were restricted to medial hypertrophy. Tumor necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta, platelet derived growth factor (PDGF), endothelin, Il-6, major histocompatibility complex (MHC) class II, and B7 were up-regulated in allografts in hypertensive hosts. Vascular deposition of immunoglobulin (IgG) was increased. These changes were markedly less pronounced in Gp 3 isografts and minimal in the kidneys of the normotensive animals of Gps 2 and 4.

CONCLUSIONS

An experimental model is presented that examines the influence of recipient hypertension in the pathogenesis of chronic dysfunction and injury developing in rat renal allografts over time.

Angiographic evaluation and treatment of transplant renal artery stenosis

Transplant renal artery stenosis is an uncommon but important complication of renal transplantation. It is a potentially reversible cause of patient morbidity and allograft dysfunction, which can present both early and late in the post-transplant period. Although transplant renal artery stenosis can be detected using noninvasive imaging, definitive diagnosis and percutaneous treatment typically require the use of invasive angiographic techniques. In experienced hands, these studies can be performed safely, effectively and with a low risk of contrast induced nephrotoxicity when alternative contrast agents are used.

Cardiovascular effects of an immunosuppressive agent cyclosporin A

Cyclosporin A (CsA) is now routinely used for transplantation of all solid organs, bone marrow transplantation, and for an increasing number of immunological diseases. However, treatment with CsA is an important iatrogenic cause of post-transplant hypertension, hyperlipidemia, and diabetes, which may contribute to the high cardiovascular morbidity in transplant recipients. Recently, the calcineurin inhibitor CsA has been employed in vivo and in vitro to examine the role of calcineurin in the signal transduction leading to cardiac hypertrophy. A cell culture study demonstrated the inhibitory effect of CsA on cytokine production by cardiac myxoma cells, the most common primary tumor of the heart. This review discusses recent data on the cardiovascular effects of CsA.

Ambulatory blood pressure monitoring in children with aortic coarctation and kidney transplantation

BACKGROUND

Ambulatory blood pressure monitoring (ABPM) has been found to be of significant importance in clinical practice because numerous blood pressure (BP) measurements may be made throughout the 24-hour period.

OBJECTIVE

To assess the clinical utility of ABPM in children with secondary hypertension.

METHODS

We studied 37 patients (21 boys and 16 girls), with a mean age of 16.4 +/- 4.1 years, after kidney transplantation and 38 patients (27 boys and 11 girls), with a mean age of 10.2 +/- 2.1 years, after surgical correction of aortic coarctation. Data, expressed as mean +/- SD, were analyzed after dividing the patients into 4 groups. Group A consisted of 25 patients receiving antihypertensive therapy; group B included 12 patients not receiving antihypertensive therapy. Group C included 25 patients operated on before 3 years of age (8 +/- 7 months of age); group D included 13 patients operated on after 3 years of age (74 +/- 29 months of age).

RESULTS

In groups A and B, casual BP measurement showed that 16 of 37 patients (43%) were hypertensive; 24-hour ABPM detected a larger number of patients who were hypertensive (23 of 37, 62%); there were 18 in group A and 5 in group B. In groups C and D, casual BP measurement identified 6 of 38 (15%) patients as hypertensive, whereas 24-hour ABPM again identified a higher number (13 of 38, 34%).

CONCLUSIONS

Our findings confirm that 24-hour ABPM is more sensitive than casual BP in detecting abnormal BP in patients at high risk for secondary hypertension.

Abnormal 24-hour blood pressure patterns in children after renal transplantation

Hypertension after renal transplantation occurs commonly and is associated with decreased allograft survival. Hypertension is usually diagnosed by casual blood pressure (BP) measurements in the outpatient clinic that may not reflect the overall 24-hour BP pattern. To better describe the pattern of BP in children after renal transplantation, 24-hour ambulatory BP monitoring (APBM) was performed in 42 patients with stable renal function. BP was measured every 20 minutes during the daytime and every 30 minutes at night. Mean patient age was 12.8 +/- 5.2 years, and mean time after transplantation was 34 +/- 36 months. Seventy-six percent of the patients were administered antihypertensive medications. Twenty-four-hour mean systolic BP (SBP) was 127 +/- 11 mm Hg, and diastolic BP (DBP) was 80 +/- 11 mm Hg. Mean 24-hour BP load values (percentage of BP readings > 95th percentile based on Task Force criteria) were 59% for SBP and 50% for DBP, which were significantly elevated compared with healthy children (P < 0.001). An attenuated decline in sleep BP (nondipping) was found in 78% of the patients for SBP and 50% for DBP. Sleep BP exceeded awake BP in 24% of the patients for SBP and 17% for DBP. Boys had a greater SBP load (66% versus 45%; P = 0.03) and DBP load (57% versus 38%; P = 0.04) than girls. These results confirm in children the high prevalence of hypertension by ABPM criteria after renal transplantation and show attenuation of normal sleep BP decreases. These BP disturbances may shorten renal allograft survival and predispose children to long-term hypertensive end-organ damage.

Use of anti-hypertensive medications and post-transplant renal allograft function in children

Post-transplant hypertension is a common occurrence in children. The relative effect of this hypertension on renal allograft function is uncertain. Examining the accumulated data for pediatric renal transplant recipients at our institution from monthly visits for up to three years, we determined whether the use of anti-hypertensive medications (anti-HTN medications) was associated with allograft dysfunction. Monthly clinical data included height, weight, serum creatinine, cyclosporin A (CsA) trough levels, number of acute rejection episodes, and number of anti-HTN medications. Estimated glomerular filtration rate (eGFR) was calculated monthly for each patient using the Schwartz formula. Time post-transplant was grouped into 6-month intervals. One thousand three hundred and sixty-three monthly data sets from 6 months (n = 76 patients) to 3 yr post-transplant (n = 47 patients) were analyzed. Overall mean eGFR was 75 mL/min/1.73 m2 at 6 months and 54 mL/min/1.73 m2 at 3 yr. A lower eGFR was found at all post-transplant time intervals for patients receiving anti-HTN medications compared with those who were not (p < 0.01). This lower eGFR was found at some but not all times post-transplant when patients were grouped by donor type or history of acute rejection episodes and analyzed separately. Mean CsA trough levels were higher at all post-transplant time intervals in patients receiving anti-HTN medications (p < 0.05). While a causal relationship between post-transplant hypertension and graft dysfunction cannot be established from this study, we conclude that the need for anti-HTN medications is associated with worse allograft function.

Antihypertensive medication and renal allograft failure: a North American Pediatric Renal Transplant Cooperative Study report

Hypertension after renal transplantation occurs commonly and, in adults, is associated with decreased graft survival. The North American Pediatric Renal Transplant Cooperative Study database was analyzed to determine: (1) the percent use of antihypertensive (anti-HTN) medication based on donor type, race, age, and acute rejection status; and (2) whether use of anti-HTN medication is associated with higher rates of subsequent graft failure. Data regarding anti-HTN medication use was available in 5251 renal allografts (4821 patients) with >30 d graft function. Posttransplant follow-up data were collected at 30 d, 6 mo, 12 mo, and then annually for 5 yr. At each follow-up, patients were selected for further analysis if the graft was functioning at that visit and subsequent follow-up data were available. Overall, anti-HTN medication use was 79% on day 30 and 58% at 5 yr. At each follow-up, anti-HTN medication use was higher (P < 0.01) for cadaveric donor versus living related donor, blacks versus whites, age >12 versus <12 yr, and > or = 1 versus 0 acute rejection episodes. Anti-HTN medication use at each annual follow-up was associated with significantly higher rates of subsequent graft failure. Multiple regression analysis controlling for all factors associated with increased use of anti-HTN medications revealed a relative risk of graft failure for use of anti-HTN medication of greater than 1.4 (P < 0.001). In recipients of cadaveric allografts, only acute rejection status predicted subsequent graft failure more strongly than use of anti-HTN medications. These data suggest that hypertension after renal transplantation in children, as evidenced by use of anti-HTN medications, is associated with increased rates of subsequent graft failure.

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.

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.

Gadolinium-based contrast and carbon dioxide angiography to evaluate renal transplants for vascular causes of renal insufficiency and accelerated hypertension

PURPOSE

To evaluate the utility and potential nephrotoxicity of gadolinium-based contrast angiography when used with carbon dioxide angiography in renal transplant patients with suspected vascular causes of renal insufficiency and/or accelerated hypertension.

MATERIALS AND METHODS

Thirteen consecutive renal transplant patients with suspected vascular causes of renal insufficiency and/or accelerated hypertension were evaluated with gadolinium-based contrast and CO2 angiography with use of digital subtraction techniques. Stenotic lesions were treated with angioplasty with/or without stent placement. No iodinated contrast agents were used. Serum creatinine levels were obtained before and at 24 and 48 hours after the procedure. An increase in creatinine levels greater than 0.5 mg/dL (44 micromol/L) was considered significant.

RESULTS

Nine patients were studied for renal insufficiency, two for accelerated hypertension, and two for both. All 13 studies were considered diagnostic. Significant stenoses were treated in four patients with angioplasty with or without stent placement. Two patients had progression of their renal insufficiency. One of these patients underwent biopsy and was found to have both acute and chronic rejection. The other patient underwent cardiac catheterization 2 days after a transplant renal artery angioplasty. In the remaining nine patients with renal insufficiency (creatinine range, 1.8-3.9 mg/dL [159-345 micromol/L]; mean, 2.7 mg/dL [239 micromol/L]), renal function improved or did not worsen.

CONCLUSION

Based on this limited study, gadolinium-based contrast angiography appears to be a promising supplement to CO2 angiography for the diagnosis and treatment of vascular lesions in patients with renal transplant insufficiency and/or accelerated hypertension. Further study is necessary to determine safety, optimal gadolinium dosage, and imaging parameters.

Care of the renal transplant recipient: a field guide for the generalist

More than 60,000 kidney transplant recipients currently live in the United States. It is not uncommon for these persons to receive medical care through a primary care physician. The widely held belief that only physicians and surgeons with "special knowledge" can care for these patients is clearly not the case. In addition to considering the immediate posttransplantation problems, this section attempts to demystify the care of kidney transplant recipients beyond the first few months of recovery after surgery. It also serves as a guide to help determine which problems can be handled by a primary care physician and which indicate referral back to the transplant center. Common infectious problems, both bacterial and viral, are discussed. This section also considers metabolic abnormalities such as hypertension, increased lipids, gout, calcium/bone diseases, and hematologic issues. Common conditions that cause real or perceived decreases in function but are not related to graft rejection are also explained.

Treatment of posttransplant hypertension by laparoscopic bilateral nephrectomy?

BACKGROUND

Hypertension is an important risk factor for the development of chronic graft failure and decreased graft and patient survival after renal transplantation.

METHODS

Between September 1994 and August 1996, 14 patients underwent laparoscopic bilateral nephrectomy for treatment of drug-resistant hypertension after successful renal transplantation. Common causes of hypertension were largely excluded before bilateral nephrectomy. A scoring system was developed for comparison of different antihypertensive regimes. In this system, points were given according to type and dosage of each antihypertensive drug.

RESULTS

At 6-month follow-up, all patients showed well-controlled blood pressure (median of mean arterial pressure: 104 vs. 130 mmHg preoperatively, P<0.001, n=14), and significantly fewer antihypertensive drugs were needed according to the scoring system (48.9+/-20.9 points vs. 105.9+/-23.5 points preoperatively, P<0.001, n=14). During laparoscopy, three conversions to open surgery were necessary. Postoperatively, four complications occurred. After laparoscopy, immunosuppression and other oral medication were given continuously. The hospital stay ranged between 3 and 6 days (median: 5 days).

CONCLUSIONS

The results indicate that bilateral nephrectomy using the laparoscopic technique can be an effective alternative method for a selected group of patients with severe hypertension, which is unresponsive to conservative management after successful renal transplantation with regard to improving the long-term graft survival.

Primary care of patients with renal transplants

The number of renal transplant recipients in the community continues to rise due to improved organ and patient survival. With increasing emphasis on primary care, more organ transplant recipients are being cared for by primary care physicians. This article outlines the management of renal transplant recipients and reviews the problems unique to this group of patients.

Beneficial effect of renal transplantation on cognitive brain function

Cognitive brain dysfunction is a common complication of end-stage renal disease. To investigate the cerebral effect of renal transplantation, we studied P300 event-related potentials--an objective marker of cognitive brain function--trailmaking test and Mini-mental state in 15 chronic hemodialysis patients and 45 matched healthy subjects. Before transplantation, patients showed prolonged P300 latency (364 vs. 337 ms, P < 0.01), smaller amplitude (15.2 vs. 19.1 microV) and scored lower (P < 0.05) in trailmaking test and Mini-mental state as compared to healthy subjects. Following renal transplantation (14 months), P300 latency decreased (337 ms, P < 0.01 vs. before) and amplitude increased (17.4 microV, P < 0.05 vs. before), indicating improved cognitive brain function. The trailmaking test and Mini-mental state tended to improve. Following transplantation, P300 findings, trailmaking test and Mini-mental state were not different from healthy subjects. Additional studies following erythropoietin treatment in 6 of the 15 hemodialysis patients revealed decreased (improved) P300 latency (351 vs. 379 ms before, P < 0.05) with further decrease following transplantation (341 ms, P = 0.06). Our findings indicate that cognitive brain dysfunction in hemodialysis patients may be fully reversed by successful renal transplantation.

Outcome of renal transplant recipients in the ICU

OBJECTIVE

To determine the outcome of renal transplant recipients in an intensive care unit (ICU).

DESIGN

Prospective, cohort study.

SETTING

Surgical ICU in a tertiary care hospital.

PATIENTS

Consecutive adult renal transplant recipients admitted to an ICU.

MEASUREMENTS AND MAIN RESULTS

Demographic data, underlying diseases, indications for admission to the ICU, number of prior kidney transplantations, duration of immunosuppression, duration of mechanical ventilation, length of stay in ICU and hospital, and ICU and hospital mortality were recorded. Seventy-one patients were included in the study. Twenty-seven patients were admitted to the surgical ICU immediately after renal transplantation surgery for postoperative monitoring (group 1). One patient died in this group. The remaining 44 patients were renal transplant recipients admitted to the surgical ICU with various complications (group 2). The mean posttransplant time in group 2 was 23 +/- 30 months. Seven patients died in group 2. The overall ICU mortality in this study was 11% and hospital mortality was 14%. The hospital mortality for postoperative patients (3.7% in group 1) was below the rate predicted based on the acute physiology and chronic health evaluation (APACHE II) score (15%). APACHE II score, duration of mechanical ventilation, and ICU length of stay were significantly higher among nonsurvivors. The ICU mortality among renal transplant recipients was higher than that of other patients (6%) admitted to the surgical ICU during the study period.

CONCLUSION

The ICU mortality of renal transplant recipients was twice that of general surgical ICU patients. The hospital mortality rate for recipients admitted immediately postoperatively to the ICU (group 1) was less than predicted by APACHE II.

Analysis of hypertension in children post renal transplantation--a report of the North American Pediatric Renal Transplant Cooperative Study (NAPRTCS)

Hypertension is common in children after renal transplantation and is associated with multiple factors. Data regarding the prevalence of post-transplant hypertension and the relationship between immunosuppressive drugs and the persistence of hypertension in a large population of North American children have not been available. This study was designed by the North American Pediatric Renal Transplant Cooperative Study to evaluate in a large diverse multicenter population of children the prevalence of hypertension post transplantation, the type of antihypertensive medications used to treat this hypertension and to determine the relationship between the blood pressure control and the immunosuppressive therapy. Analysis of 277 patients showed the following: (1) 70% of recipients required antihypertensive medications 1 month post transplant compared with 48% pre transplant; the incidence decreased to 59% at 24 months; (2) the majority of children received multiple drug therapy to control blood pressure; (3) hypertension can be controlled effectively despite inherent etiological factors, such as allograft source, prior hypertension and immunosuppressive therapy.

ACE inhibitors in non-diabetic renal disease

In non-diabetic renal disease ACE inhibitors have brought both benefit and problems. On the one hand, they are undoubtedly effective antihypertensive agents and data suggest that they may have a beneficial role in the prevention of progression of renal disease, although further placebo controlled double blind trials of adequate duration are required. On the other hand, their widespread use in elderly patients and those with generalised atherosclerosis has increased the risk of acute renal failure when occult renovascular disease is present. Awareness among physicians of the high rate of renovascular disease in populations at risk is to be encouraged.

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.

The role of hypertension as a damaging factor for kidney grafts under cyclosporine therapy

The relative importance of glomerular filtration rate (GFR) and hypertension (permanent need for antihypertensive drugs) for the prognosis of kidney grafts was studied in 135 cyclosporine-treated primary cadaver kidney transplant recipients whose grafts lasted more than 1 year. The start point of 1 year after transplantation was chosen because hypertension developed within the first year in all our hypertensive patients. Graft prognosis in hypertensive patients was not significantly worse than that of normotensive patients; moreover at multivariate analysis, age at transplantation and GFR at 1 year (P = 0.014), but not hypertension, were significant prognostic factors for the graft. At logistic regression, GFR was a significant variable for hypertension (P = 0.009), but hypertension was not a significant variable for renal failure at 1 year (GFR < or = 0.83 mL/sec [50 mL n]; P, NS). Accordingly, hypertension per se resulted much more as a consequence of reduced renal function than as a direct cause of graft damage. However, when hypertensive patients were divided into controlled and uncontrolled, uncontrolled hypertensive patients had the worst prognosis (P = 0.03), and blood pressure control proved a strong prognostic factor for the graft, even after GFR was considered (P = value of the model considering blood pressure control, GFR, and age at transplantation: 0.007). Our data suggest that, apart from being an expression of reduced renal function, hypertension is also a direct kidney graft damaging agent, a role that can be controlled by strict reduction of blood pressure levels.

Nephron underdosing: a programmed cause of chronic renal allograft failure

The findings cited in this report suggest that renal allograft survival might be improved by matching nephron supply to recipient needs (analogous to prescription dialysis based on Kt/V). Methods for assessing functional graft capacity (ie, nephron number, filtration, or total microvascular surface area) are needed. Graft weights might serve as a useful alternative until better indices are devised. Measures for defining and possibly reducing recipient demands are also needed to preserve graft performance. Where gross imbalances between nephron supply and recipient demand are not likely to be corrected over the long term by engraftment of a single kidney, consideration should be given to dual kidney transplantation, currently feasible only from cadaveric, but eventually from xenogeneic sources as well. The predicted longer survival and avoidance of premature return to end-stage renal disease with the transplantation of two kidneys in certain conditions could render this approach more rational, both in clinical and economic terms, than single kidney engraftment for those at greatest risk for shortened graft survival. The dosing of larger numbers of nephrons might also lessen the risk of coexistent hypertension and thereby reduce the magnitude and tempo of immune injury to the graft.

Renal effects of cyclosporine

Renal dysfunction is a frequent consequence of cyclosporine administration, even when cyclosporine blood concentrations are maintained within proper therapeutic levels. As dermatologic indications for this compound expand, it is important for clinicians to understand the relevant pharmacology and physiology that underlie cyclosporine-induced renal dysfunction. This article reviews the clinical pharmacology of cyclosporine, the principles of renal function testing, and the clinical manifestations of this drug's effects on the kidney. Sudden declines in kidney function, long-term cyclosporine nephrotoxicity, hemolytic-uremic syndrome, and hypertension are discussed from a clinical and experimental standpoint. Finally, practical suggestions are provided to aid the dermatologist in managing cyclosporine-treated patients.

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.