The efficacy and safety of a pharmacologic protocol for maintaining coronary artery bypass patients at a higher mean arterial pressure during cardiopulmonary bypass. 1998

A recent randomized trial of higher versus lower mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) showed that higher MAP on CPB was associated with a lower incidence of overall cardiac and neurologic morbidity and mortality in coronary artery bypass graft surgery (CABG) patients. Cardiopulmonary bypass MAP was controlled pharmacologically while CPB flow was held constant for any given period. The objective of the present study was to assess the efficacy and safety of this pharmacologic protocol. Two hundred forty-eight patients participated in the study; the mean age was 65.8 ± 9.4 years, 20% were women, and the mean preoperative ejection fraction was 48%. The low-flow corrected CPB MAP attained for the low and high MAP groups was 56.7 ± 5.0 mmHg and 77.7 ± 7.1 mmHg, respectively (p = 0.0001). Major cardiac and neurologic outcomes, postoperative blood loss, renal dysfunction, intensive care unit (ICU) stay, and duration of intubation were not found to be significantly associated with any drug in the pharmacologic protocol. These findings support that the pharmacologic protocol used to maintain CABG patients at higher MAP on CPB is both efficacious and safe.

Changing health behaviors to improve health outcomes after angioplasty: a randomized trial of net present value versus future value risk communication

Patients who have undergone angioplasty experience difficulty modifying at-risk behaviors for subsequent cardiac events. The purpose of this study was to test whether an innovative approach to framing of risk, based on 'net present value' economic theory, would be more effective in behavioral intervention than the standard 'future value approach' in reducing cardiovascular morbidity and mortality following angioplasty. At baseline, all patients completed a health assessment, received an individualized risk profile and selected risk factors for modification. The intervention randomized patients into two varying methods for illustrating positive effects of behavior change. For the experimental group, each selected risk factor was assigned a numeric biologic age (the net present value) that approximated the relative potential to improve current health status and quality of life when modifying that risk factor. In the control group, risk reduction was framed as the value of preventing future health problems. Ninety-four percent of patients completed 2-year follow-up. There was no difference between the rates of death, stroke, myocardial infarction, Class II-IV angina or severe ischemia (on non-invasive testing) between the net present value group and the future value group. Our results show that a net present risk communication intervention did not result in significant differences in health outcomes.

Non-invasive observation of repeated adenoviral GFP gene delivery to the anterior segment of the monkey eye in vivo

BACKGROUND

Glaucoma is a group of chronic eye diseases often associated with an elevated intraocular pressure (IOP). If not controlled, the condition leads to blindness. The eye tissue responsible for maintaining aqueous humor resistance and thus normal IOP is the trabecular meshwork (TM). Adenoviral vectors are capable of transducing the TM in several rodent species. Because of the relevance of the non-human primate model in the study of glaucoma, gene transfer to the eyes of cynomolgus monkeys was investigated.

METHODS

Four cynomolgus monkeys were injected with AdenoGFP into the anterior chamber: two monkeys received 10(9) pfu and the other two 10(7) pfu. One monkey received four consecutive injections into the same eye (10(7) pfu in each injection) over a 7-month period. In vivo gene transfer (fluorescence) and IOP were evaluated by standard clinical ophthalmic instruments (slit lamp biomicroscopy, gonioscopy and tonometry). Histopathology and cellular distribution were assessed postmortem.

RESULTS

The first injection of the lower viral dose resulted in marked TM-preferred gene transfer visible non-invasively by in vivo gonioscopy. The expression of the transgene lasted for 3-4 weeks with little or no signs of clinical inflammation. Gene transfer was achieved on three sequential occasions (3-4 weeks each) but failed and induced substantial, albeit reversible, corneal abnormalities on the fourth occasion.

CONCLUSIONS

Gene transfer to the TM and cornea can be monitored non-invasively in non-human primates, allowing correlation of gene transfer with physiological parameters. Because of ocular immune privilege, repeated anterior chamber administrations of adenoviral vectors expressing appropriate genes may have therapeutic potential for glaucoma.

What level of plasma homocyst(e)ine should be treated? Effects of vitamin therapy on progression of carotid atherosclerosis in patients with homocyst(e)ine levels above and below 14 micromol/L

High levels of plasma homocyst(e)ine (H[e]) are associated with increased vascular risk. Treatment is being contemplated, but the level at which patients should be treated is not known. We compared the response of carotid plaque to vitamin therapy in patients with H(e) above and below 14 micromol/L, a level commonly regarded as high enough to warrant treatment. Two-dimensional B-mode ultrasound measurement of carotid plaque was used to assess the response to vitamin therapy with folic acid 2.5 mg, pyridoxine 25 mg, and cyanocobalamin 250 microg daily, in 101 patients with vascular disease (51 with initial plasma levels above, and 50 below 14 micromol/L). Among patients with plasma H(e) >14 micromol/L, the rate of progression of plaque area was 0.21 +/- 0.41 cm2/year before vitamin therapy, and -0.049 +/- 0.24 cm2/year after vitamin therapy (P2 = .0001; paired t test). Among patients with levels <14 micromol/L, the rate of progression of plaque was 0.13 +/- 0.24 cm2/year before vitamin therapy and -0.024 +/- 0.29 cm2/year after vitamin therapy (P2 = .022, paired t test). The change in rate of progression was -0.15 +/- .44 cm2/year below 14 micromol/L, and -0.265 +/- 0.46 cm2/year above 14 micromol/L (P = 0.20). Vitamin therapy regresses carotid plaque in patients with H(e) levels both above and below 14 micromol/L. These observations support a causal relationship between homocyst(e)ine and atherosclerosis and, taken with epidemiologic evidence, suggest that in patients with vascular disease, the level to treat may be <9 micromol/L.

Predictors and outcomes of cardiac complications following elective coronary bypass grafting

Our objective was to determine the predictors of cardiac complications among a cohort of elective coronary artery bypass graft (CABG) surgery patients and to determine the relationship of such complications to subsequent quality of life and symptoms. A total of 248 patients were enrolled and 237 completed 6 month follow-up. The combined rate of both major and minor cardiac complications was 9.7% (n = 24). Patients in this study were evaluated preoperatively, monitored intraoperatively, followed immediately postoperatively and at 6 months. Major cardiac complications accounted for 3.6% (n = 9) and minor complications for 6% (n = 15). Using multivariable logistic regression analysis, the predictors of major cardiac complications were receiving diuretics preoperatively (p = .01) and increased time during cross-clamping (p = .006). At 6 months after surgery, 19% of the patients with postoperative cardiac complications experienced worsening of symptoms, in contrast to only 8% of those without cardiac complications (p = .03). We concluded that patients who were on preoperative diuretics and those who had longer cross-clamp times were at higher risk of cardiac complications. The majority of patients who had acute cardiac complications had improved function and symptoms at 6 months postoperatively.

Depressive symptomatology in coronary artery bypass graft surgery patients

Depression is commonly reported in coronary artery bypass graft (CABG) surgery patients. This study assesses the relationship of preoperative characteristics, life stressors, social support, major cardiac and neurologic outcomes and other complications to depressive symptomatology. Demographic and clinical data, CES-D score and information on life stressors and social support were collected from 237 patients; 92% completed 6-month follow-up. CES-D score > or = 16 was defined as significant depressive symptomatology. Significant depressive symptomatology was found in 43% of patients preoperatively and 23% postoperatively. In multivariate models, low social support (p = 0.008), presence of at least one life stressor within a year of surgery (p = 0.006), moderate to severe dyspnea (p = 0.003), little to no available help (p = 0.05) and less education (p = 0.05) were associated with higher preoperative CES-D score, while longer intensive care unit (ICU) stay (p = 0.0001) and little or no available help (p = 0.0008) predicted higher postoperative CES-D scores when controlling for preoperative CES-D scores. Neither pre- nor postoperative depressive symptomatology was related to major outcomes or other complications. A high rate of significant depressive symptomatology exists in CABG patients preoperatively, and it decreases significantly postoperatively. Patients with the above preoperative characteristics as well as those who stay in the ICU postoperatively for more than 2 days might benefit from psychosocial interventions.

[The mechanical fundus perfusion model: blood flow velocity determined by ICG angiography and Heidelberg retina flowmetry]

BACKGROUND

Heidelberg Retina Flowmetry (HRF) is now popularly, perhaps even indiscriminately applied in eye research, without apparent concern for the fact that the results are given numerically, but without physical units.

METHODS

1) HRF: To challenge the HRF-device with known values of blood-flow velocity, a perfusion chamber with input and output connections was constructed of acrylic plastic. Three serial segments were milled to provide cross-sectional areas (1.93 mm2, 3.33 mm2, and 5.08 mm2) and accordingly decreasing, true, clinically representative flow-velocity values. Under a constant perfusion setting of a calibrated clinical infusion pump (Perfusor Secura FT, B. Braun Medical AG, Sempach, CH), heparinized human blood (P. H.) was pumped through the chamber, and the HRF-parameter, "VELOCITY" was measured within one image encompassing the three chamber segments, using a 20 degrees x 5 degrees-field and a 20 x 20-pixel measuring "window". 2) HRA: Immediately thereafter, our perfusion model was placed in front of the Heidelberg Retina Angiography device, the infusion pump started at the same constant level, and a 1 cc bolus of ICG dye was added to the blood. Digital ICG-angiography was then conducted, and the images analyzed on-screen.

RESULTS

In the three segments of the perfusion chamber, flow velocities determined ICG-angiographically were 11.5 mm/s, 6.7 mm/s, and 4.4 mm/s, respectively. The corresponding values for HRF- "VELOCITY" were 5.3, 4.2, and 3.4, respectively (no units).

CONCLUSIONS

Under identical perfusion conditions, the phenomenologically (ICG-angiographically) determined values of flow velocity in the 3 perfusion chamber segments ran similar to (but not numerically coincidental with) those determined for HRF-parameter "VELOCITY". Extrapolation of HRF-values to true physical units is, thus, feasible.

Development, implementation, and evaluation of a ketoconazole practice guideline for ARDS prophylaxis

PURPOSE

The purpose of this study was to develop, implement, and evaluate a practice guideline using ketoconazole for the prevention of the adult respiratory distress syndrome (ARDS) in critically ill patients.

MATERIALS AND METHODS

In hospital A (study hospital), we developed a guideline for ketoconazole prophylaxis in patients at high risk of ARDS using evidence from two randomized trials. We prospectively implemented the guideline using intensive care unit (ICU) teaching sessions, in-services, informational posters, and patient-specific individual audit and feedback. ICU caregivers in hospital B (concurrent control hospital) did not participate in the guideline development or implementation and were unaware of the conduct of the study.

RESULTS

Patients at risk of ARDS were similar in hospitals A and B. Implementation of the guideline was associated with a significantly higher use of ketoconazole use for ARDS prevention (P < .0001) and a significantly lower rate of ARDS (P < .05) in hospital A compared with hospital B. Mortality, duration of ventilation, and ICU stay were similar.

CONCLUSION

Development and implementation of a prophylactic ketoconazole practice guideline for ICU patients at high risk of ARDS was associated with a higher prescription of ketoconazole and a lower rate of ARDS in the study hospital than in the control hospital.

The efficacy and safety of a pharmacologic protocol for maintaining coronary artery bypass patients at a higher mean arterial pressure during cardiopulmonary bypass

A recent randomized trial of higher versus lower mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) showed that higher MAP on CPB was associated with a lower incidence of overall cardiac and neurologic morbidity and mortality in coronary artery bypass graft surgery (CABG) patients. Cardiopulmonary bypass MAP was controlled pharmacologically while CPB flow was held constant for any given period. The objective of the present study was to assess the efficacy and safety of this pharmacologic protocol. Two hundred forty-eight patients participated in the study; the mean age was 65.8 +/- 9.4 years, 20% were women, and the mean preoperative ejection fraction was 48%. The low-flow corrected CPB MAP attained for the low and high MAP groups was 56.7 +/- 5.0 mmHg and 77.7 +/- 7.1 mmHg, respectively (p = 0.0001). Major cardiac and neurologic outcomes, postoperative blood loss, renal dysfunction, intensive care unit (ICU) stay, and duration of intubation were not found to be significantly associated with any drug in the pharmacologic protocol. These findings support that the pharmacologic protocol used to maintain CABG patients at higher MAP on CPB is both efficacious and safe.

Achievement and safety of a low blood pressure goal in chronic renal disease. The Modification of Diet in Renal Disease Study Group

The Modification of Diet in Renal Disease Study showed a beneficial effect of a lower-than-usual blood pressure (BP) goal on the progression of renal disease in patients with proteinuria. The purpose of the present analyses was to examine the achieved BP, baseline characteristics that helped or hindered achievement of the BP goals, and safety of the BP interventions. Five hundred eighty-five patients with baseline glomerular filtration rate between 13 and 55 mL/min per 1.73 m2 (0.22 to 0.92 mL/s per 1.73 m2) were randomly assigned to either a usual or low BP goal (mean arterial pressure < or = 107 or < or = 92 mm Hg, respectively). Few patients had a history of cardiovascular disease. All antihypertensive agents were permitted, but angiotensin-converting enzyme inhibitors (with or without diuretics) followed by calcium channel blockers were preferred. The mean (+/- SD) of the mean arterial pressures during follow-up in the low and usual BP groups was 93.0 +/- 7.3 and 97.7 +/- 7.7 mm Hg, respectively. Follow-up BP was significantly higher in subgroups of patients with preexisting hypertension, baseline mean arterial pressure > 92 mm Hg, a diagnosis of polycystic kidney disease or glomerular diseases, baseline urinary protein excretion > 1 g/d, age > or = 61 years, and black race. The frequency of medication changes and incidence of symptoms of low BP were greater in the low BP group, but there were no significant differences between BP groups in stop points, hospitalizations, or death. When data from both groups were combined, each 1-mm Hg increase in follow-up systolic BP was associated with a 1.35-times greater risk of hospitalization for cardiovascular or cerebrovascular disease. Lower BP than usually recommended for the prevention of cardiovascular disease is achievable by several medication regimens without serious adverse effects in patients with chronic renal disease without cardiovascular disease. For patients with urinary protein excretion > 1 g/d, target BP should be a mean arterial pressure of < or = 92 mm Hg, equivalent to 125/75 mm Hg.

Macrophages and chronic renal allograft nephropathy

In a previous study we demonstrated that macrophage infiltrates stained for thromboxane A synthase (TxAS) correlated inversely with renal function six months after biopsy. We propose that macrophage based inflammation is a cofactor leading to chronic allograft nephropathy. For this study we compared four indices of renal allograft nephropathy with renal survival. The Banff Score of Inflammatory Changes (BSI) is an index of acute inflammation. The Banff Chronic Index (BCI) and Chronic Allograft Damage Index (CADI) are indexes of chronic disease. The Macrophage Index (MI) is the same as the BSI applied only to macrophages. These indices were determined on renal allograft biopsies obtained because of delayed graft function within the first week of transplantation, and for increasing plasma creatinine levels after stable function. All four indices predicted renal survival in the post-biopsy interval. MI predicted renal survival for the entire transplant period. In addition, the presence of TxAS transcripts in the renal allografts was determined using a reverse transcription-polymerase chain reaction-based assay. This confirms previous observations of TxAS in the grafts. This study supports the hypothesis that macrophage derived inflammation is a cofactor for chronic allograft nephropathy.

Severity of aortic atheromatous disease diagnosed by transesophageal echocardiography predicts stroke and other outcomes associated with coronary artery surgery: a prospective study

Advanced atheromatous disease of the thoracic aorta identified by transesophageal echocardiography (TEE) is a major risk factor for perioperative stroke. This study investigated whether varying degrees of atherosclerosis of the descending aorta, as assessed by TEE, are an independent predictor of cardiac and neurologic outcome in patients undergoing coronary artery bypass grafting (CABG). Intraoperative TEE of the descending aorta was performed on 189 of 248 patients participating in a randomized controlled trial of low (50-60 mm Hg) or high (80-100 mm Hg) mean arterial pressure during cardiopulmonary bypass for elective CABG. Aortic atheromatous disease was graded from I to V in order of increasing severity by observers blinded to outcome. Measured outcomes were death, stroke, and major cardiac events assessed at 1 wk and 6 mo. Nine of the 189 patients with TEE examinations had perioperative strokes by 1 wk. At 1 wk, no strokes had occurred in the 123 patients with atheroma Grades I or II, while the 1-wk stroke rate was 5.5% (2/36), 10.5% (2/19), and 45.5% (5/11) for Grades III, IV, and V, respectively (Fisher's exact test, P = 0.00001). For 6-mo outcome, advancing aortic atheroma grade was a univariate predictor of stroke (P = 0.00001) and death (P = 0.03). By 6 mo there were one additional stroke, three additional deaths, and one additional major cardiac event. Atheromatous disease of the descending aorta was a strong predictor of stroke and death after CABG. TEE determination of atheroma grade is a critical element in the management of patients undergoing CABG surgery.

Measurement of organochlorine levels in postprandial serum or in blood collected in serum separator tubes

Whether organochlorine blood levels in fasting and postprandial specimens provide equivalent measures of exposure and the extent to which collecting blood in tubes containing material to separate serum and blood cells corrupts the specimen are unclear. In this paper, we present data from two studies that address both of these issues. In the first study, 27 women provided fasting blood in plain, silicone-coated Vacutainer tubes (red-topped) and in similar tubes containing serum separator gel (SSTs), as well as a postprandial specimen in a red-topped tube. The specimens collected in SSTs were left to stand overnight, with the gel in contact with the sample. In the second study, the blood of 12 industrial incinerator workers was collected in red-topped tubes and in SSTs. Blood in SSTs was left in contact with the gel for 5 days. Serum organochlorine residue levels ([1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] (DDE)) and polychlorinated biphenyls) in samples collected in red-topped tubes were highly correlated with levels measured in samples collected in SSTs (all Pearson r values were > or = 0.79). Postprandial and fasting organochlorine levels were also highly correlated (Pearson r values > or = 0.89). Our results indicate that timing of the collection of blood in relation to meals and use of SSTs to collect blood specimens did not greatly affect the relative classification of subjects with respect to serum level of DDE or polychlorinated biphenyls. The longer the specimen was in contact with the SST gel, however, the lower the level of organochlorine that was detected and, at least for DDE, the greater the misclassification caused.

Cimetidine or ranitidine in renal transplant patients receiving cyclosporine

While H2-receptor antagonists are commonly used in renal transplant patients to prevent peptic ulcer disease, they have been associated with immunostimulation, interference with cyclosporine (CsA) metabolism, and inhibition of tubular secretion of creatinine. In renal transplant patients, cimetidine in high doses has been shown to cause a sustained rise in serum creatinine (SCr) and to reduce creatinine clearance (CrCl) with no change in inulin clearance. In this short-term prospective study, we evaluated the effects of single daily doses of cimetidine or ranitidine on renal function, and CsA serum concentration. Fourteen renal transplant patients with stable renal function were assigned to receive either cimetidine 400 mg daily or ranitidine 150 mg daily for 7 days. In patients who received cimetidine, a slight rise in SCr was observed at days 2 and 5 which was not statistically significant, but no significant change in CsA trough level was noted. No changes in SCr or CsA level were noted in the patients who received ranitidine. No changes in GFR were observed in either cimetidine- or ranitidine-treated patients. We conclude that, in our short-term study, cimetidine or ranitidine in the doses used in this study did not affect the GFR or CsA level, or SCr.

Blood pressure control, proteinuria, and the progression of renal disease. The Modification of Diet in Renal Disease Study

OBJECTIVE

To examine the relations among proteinuria, prescribed and achieved blood pressure, and decline in glomerular filtration rate in the Modification of Diet in Renal Disease Study.

DESIGN

2 randomized trials in patients with chronic renal diseases of diverse cause.

SETTING

15 outpatient nephrology practices at university hospitals.

PATIENTS

840 patients, of whom 585 were in study A (glomerular filtration rate, 25 to 55 mliters/min.1.73 m2) and 255 were in study B (glomerular filtration rate, 13 to 24 mliters/min.1.73 m2). Diabetic patients who required insulin were excluded.

INTERVENTIONS

Patients were randomly assigned to a usual blood pressure goal (target mean arterial pressure, < or = 107 mm Hg for patients < or = 60 years of age and < or = 113 mm Hg for patients > or = 61 years of age) or a low blood pressure goal (target mean arterial pressure, < or = 92 mm Hg for patients < or = 60 years of age and < or = 98 mm Hg for patients > or = 61 years of age).

MAIN OUTCOME MEASURES

Rate of decline in glomerular filtration rate and change in proteinuria during follow-up.

RESULTS

The low blood pressure goal had a greater beneficial effect in persons with higher baseline proteinuria in both study A (P = 0.02) and study B (P = 0.01). Glomerular filtration rate declined faster in patients with higher achieved blood pressure during follow-up in both study A (r = -0.20; P < 0.001) and study B (r = -0.34; P < 0.001), and these correlations were stronger in persons with higher baseline proteinuria (P < 0.001 in study A; P < 0.01 in study B). In study A, the association between decline in glomerular filtration rate and achieved follow-up blood pressure was nonlinear (P = 0.011) and was stronger at higher mean arterial pressure. In both studies, the low blood pressure goal significantly reduced proteinuria during the first 4 months after randomization. This, in turn, correlated with a slower subsequent decline in glomerular filtration rate.

CONCLUSIONS

Our study supports the concept that proteinuria is an independent risk factor for the progression of renal disease. For patients with proteinuria of more than 1 g/d, we suggest a target blood pressure of less than 92 mm Hg (125/75 mm Hg). For patients with proteinuria of 0.25 to 1.0 g/d, a target mean arterial pressure of less than 98 mm Hg (about 130/80 mm Hg) may be advisable. The extent to which lowering blood pressure reduces proteinuria may be a measure of the effectiveness of this therapy in slowing the progression of renal disease.

Improvement of outcomes after coronary artery bypass. A randomized trial comparing intraoperative high versus low mean arterial pressure

BACKGROUND

The objective of this randomized clinical trial of elective coronary artery bypass grafting was to investigate whether intraoperative mean arterial pressure below autoregulatory limits of the coronary and cerebral circulations was a principal determinant of postoperative complications. The trial compared the impact of two strategies of hemodynamic management during cardiopulmonary bypass on outcome. Patients were randomized to a low mean arterial pressure of 50 to 60 mm Hg or a high mean arterial pressure of 80 to 100 mm Hg during cardiopulmonary bypass.

METHODS

A total of 248 patients undergoing primary, nonemergency coronary bypass were randomized to either low (n = 124) or high (n = 124) mean arterial pressure during cardiopulmonary bypass. The impact of the mean arterial pressure strategies on the following outcomes was assessed: mortality, cardiac morbidity, neurologic morbidity, cognitive deterioration, and changes in quality of life. All patients were observed prospectively to 6 months after the operation.

RESULTS

The overall incidence of combined cardiac and neurologic complications was significantly lower in the high pressure group at 4.8% than in the low pressure group at 12.9% (p = 0.026). For each of the individual outcomes, the trend favored the high pressure group. At 6 months after coronary bypass for the high and low pressure groups, respectively, total mortality rate was 1.6% versus 4.0%, stroke rate 2.4% versus 7.2%, and cardiac complication rate 2.4% versus 4.8%. Cognitive and functional status outcomes did not differ between the groups.

CONCLUSION

Higher mean arterial pressures during cardiopulmonary bypass can be achieved in a technically safe manner and effectively improve outcomes after coronary bypass.

Complementation of vif-defective human immunodeficiency virus type 1 by primate, but not nonprimate, lentivirus vif genes

The productive infection of many susceptible human cells, including lymphocytes and macrophages derived from peripheral blood, by the pathogenic lentivirus human immunodeficiency virus type 1 requires expression of the virally encoded vif (for virion infectivity factor) gene. Interestingly, this gene appears to have been conserved among all of the lentiviruses of primates and almost all of the lentiviruses of nonprimates. Using T cells constitutively expressing vif genes derived from diverse sources and virus replication assays, we show that the vif gene of a second primate lentivirus, simian immunodeficiency virus from macaques, complements vif-defective human immunodeficiency virus type 1 but that those of three distinct nonprimate lentiviruses do not. Although the molecular basis for Vif function has yet to be defined, the potential implications of this noted restriction of vif complementarity are discussed.

Hypomagnesemia in renal transplant patients: improvement over time and association with hypertension and cyclosporine levels

Hypomagenesemia is frequently encountered early after kidney transplantation, especially in patients receiving cyclosporine (CsA). However, there have been no studies addressing the natural history of this disorder in adult transplant recipients. We conducted this investigation to study the change in the prevalence of hypomagnesemia over time in renal transplant patients as well as to determine the factors associated with this change. Three patient groups were studied: 24 CsA-treated patients followed longitudinally at 1, 3 and 6 months post-transplant (Group 1a, 1b, 1c); 33 CsA-treated patients at least 2 years post-transplant (Group 2; mean follow-up 55 +/- 25 months); and 31 non-CsA-treated patients at least 2 years post-transplant (Group 3; mean follow-up 132 +/- 57 months). The following parameters were monitored: serum and urine magnesium levels; serum potassium; creatinine clearance; fractional excretion of magnesium; and trough CsA levels. In group 1 patients, longitudinal follow-up showed a significant linear trend for improvement in the serum magnesium over time (1.6 +/- 0.3, 1.7 +/- 0.2, 1.8 +/- 0.2 mg/dl; p = 0.0015) as well as a decline in the whole blood CsA level (316 +/- 103, 251 +/- 82, 194 +/- 67 ng/ml; p = 0.0015) at 1, 3 and 6 months, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Thromboxane synthase expression in renal transplant patients with rejection

Thromboxane synthase (TS) catalyzes the formation of thromboxane (TxA2) in monocytes/macrophages, platelets, and various tissues. TxA2 is likely to play a role in graft dysfunction due to its vasoconstrictive and platelet aggregatory properties. We studied the expression of TS in 7 normal native kidneys, 29 consecutive renal allograft biopsies (performed for rising serum creatinine, n = 23, and delayed graft function, n = 6), and one transplant nephrectomy specimen with severe acute rejection. TS expression was determined by immunocytochemistry using a monoclonal antibody against human TS, Kon-7. Histologic grading of the transplant biopsy specimens was based on the Banff classification. The degree of TS staining was graded in the glomeruli, interstitium, tubules and vessels from 0 to 3+. Of 29 biopsies, 13 had chronic nephropathy (CN), 6 had acute rejection (AR) with chronic nephropathy (AR/CN), 4 had acute rejection (AR), and 6 had acute tubular necrosis (ATN). TS staining of native kidneys showed sporadic interstitial cells. The biopsy and transplant nephrectomy specimens showed significant staining, predominantly in the glomeruli and interstitium. Positively staining cells appeared to be of macrophage/monocyte lineage by morphology. The mean glomerular staining grade was significantly increased in specimens with AR (2.3 +/- 0.9) and the mean interstitial staining was increased in specimens with AR/CN (2.2 +/- 0.9). Follow-up renal function 6 months post-biopsy showed that patients with higher TS staining grades had a faster decline in graft function. In conclusion, TS expression is increased in patients with acute rejection with or without chronic nephropathy and is associated with more rapid deterioration in function.

Increased antibody responsiveness to blood transfusions in pediatric patients

Heightened immune responsiveness has been proposed as one of the reasons underlying suboptimal renal transplant results in very young children or African American recipients. Because multiple factors influence graft outcome, it has been difficult to provide experimental evidence to confirm or refute this suggestion. In the present study we measured IgG antibodies with confirmed HLA specificity produced in response to blood transfusions. The patients evaluated were renal transplant candidates who had not had previous pregnancies or transplants. The overall incidence of HLA sensitization was 12%. Age was the most influential factor in sensitization: patients < 20 years old were 4-5 times as likely to produce anti-HLA antibodies than patients > 20 (P = 0.0018). Female patients were also high responders. However, this was explained by the higher proportion of children among nulliparous female patients rather than by differences in gender. In contrast, the antibody response of black and white recipients was similar. The antibody levels in most patients were low and decreased significantly with time. We conclude that the immunoregulatory influences in patients < 20 years old favor the production of anti-HLA antibodies in response to blood transfusions, a fact that may explain some clinical observations in pediatric transplant recipients.

Increased incidence of rejection in patients with delayed graft function

Because of the difficulties in diagnosing rejection in patients with delayed graft function, such patients were routinely biopsied 7-10 days after kidney transplantation. We found histologic evidence of rejection in 48% of the cases during the lst month posttransplant, a proportion that was significantly higher than in patients with immediate graft function. Furthermore, the 2-year graft survival in patients with delayed graft function and rejection, but not in those without rejection, was significantly lower than in patients with immediate function. The results suggest that there is an association between delayed graft function and rejection and that rejection is the component responsible for the decreased graft survival previously reported for patients with delayed graft function.

Dialysis is not indicated immediately after administration of nonionic contrast agents in patients with end-stage renal disease treated by maintenance dialysis

OBJECTIVE

This study was undertaken to determine the necessity of immediate dialysis after intravascular injection of contrast material in patients with end-stage renal disease who are being maintained on hemodialysis. Although many physicians support this practice, we could find no reports of studies to confirm or refute its necessity.

SUBJECTS AND METHODS

We studied 10 patients being treated with hemodialysis who were undergoing 11 diagnostic procedures that required intravascular contrast material. The patients received 40-225 ml of nonionic contrast material and were followed up with clinical examination and laboratory analysis to determine any adverse effects from contrast administration or the need for dialysis or both.

RESULTS

No significant changes in blood pressure, ECG, total serum protein level of osmolality, extracellular fluid volume, or body weight occurred after injection of contrast material. None of the patients had clinical features that necessitated emergent dialysis.

CONCLUSION

We conclude that nonionic contrast material can be given safely to patients with end-stage renal disease who are being maintained on hemodialysis. Immediate postprocedural dialysis is unwarranted as a routine practice.

A preliminary report of diltiazem and ketoconazole. Their cyclosporine-sparing effect and impact on transplant outcome

A prospective randomized trial was conducted to compare the effect of diltiazem (DILT) with ketoconazole (KETO) on sparing of cyclosporine dose and renal transplant outcome. Renal allograft recipients 18 years old and older were eligible for the study. Triple immunosuppression (TRIPLE) including prednisone, azathioprine, and CsA was administered to all patients. The maintenance CsA dose varied by study group. Patients were randomized to receive one of three treatment strategies: group 1-TRIPLE (CsA 8 mg/kg/day); group 2--TRIPLE (CsA 6 mg/kg/day) + DILT (60 mg b.i.d.); group 3--TRIPLE (CsA 3 mg/kg/day) + KETO (200 mg/day). Modification of the DILT dose was allowed as needed to effect blood pressure control in group 2 patients. Mean 1-month CsA dose reductions were 30% and 60% of controls in group 2 and 3, respectively. A continued effect over time was observed in patients administered KETO but not DILT. At 1 year patients taking KETO required an average of 77% less CsA than the average dose necessary to effect similar parent CsA blood levels when no enzyme inhibitor was used. The use of KETO and DILT for 1 year allowed for 53% and 14% reductions in CsA cost, respectively. These savings include the cost of the KETO or DILT. Serum creatinines, mean arterial pressure (MAP), and incidence of liver function abnormalities were similar throughout treatment groups. The rate of rejection, time to rejection onset, and survival (GS/PS) were not different among the groups. Fungal infections were fewer in patients treated with KETO (12%) than in controls (16%) and patients randomized to DILT (19%). KETO failed to prevent Aspergillus infection in one individual. The investigation failed to identify any harmful result of treating renal allograft recipients with either DILT or KETO for the purpose of reducing CsA expense.

Fentanyl and sufentanil increase intracranial pressure in head trauma patients

Although opioids frequently are administered to patients with severe head trauma, the effects of such drugs on intracranial pressure are controversial. Nine patients with severe head trauma were studied for the effects of fentanyl and sufentanil on intracranial pressure (ICP). In all patients, ICP monitoring was instituted before the study. Full neuromuscular blockade was achieved with vecuronium bromide before the administration of either fentanyl (3 micrograms.kg-1) or sufentanil (0.6 microgram.kg-1) as an intravenous bolus over a 1-min period in a masked and random fashion. Patients received the other opioid in the same fashion 24 h later. Arterial blood pressure, heart rate, and ICP were recorded continuously for the 1 h after drug administration. Fentanyl was associated with an average ICP increase of 8 +/- 2 mmHg, and sufentanil with an increase of 6 +/- 1 mmHg. These increases were statistically significant. Both drugs produced clinically mild decreases in mean arterial blood pressure (fentanyl, 11 +/- 6 mmHg; sufentanil, 10 +/- 5 mmHg) that nevertheless were statistically significant. No significant changes in heart rate occurred. These results indicate that modest doses of potent opioids can significantly increase ICP in patients with severe head trauma.

An infant with trisomy 9 mosaicism presenting as a complete trisomy 9 by amniocentesis

We present a case in which amniocentesis performed at 33 weeks' gestation because of symmetrical intrauterine growth retardation and decreased amniotic fluid volume led to the prenatal diagnosis of a fetus with a karyotype of 47,XX,+9,t(1;20)(q42;p11.2) pat, i.e., with an extra chromosome 9 and a balanced translocation between chromosomes 1 and 20. At delivery, the baby showed clinical features of trisomy 9, yet chromosome analysis of the cord blood revealed no trisomy 9 cells, a finding confirmed by neonatal blood karyotyping. The balanced translocation was present in all cells. A skin biopsy confirmed trisomy 9 mosaicism with 10 per cent trisomy 9 cells. The baby died at 6 weeks and an autopsy was obtained. Chromosome analysis of different organs demonstrated different frequencies of the mosaicism of trisomy 9. The possible underlying mechanism for the discrepancy between the karyotype results by amniocentesis and those of other tissues is discussed.

Autonomic control of heart rate during exercise studied by heart rate variability spectral analysis

Spectral analysis of heart rate variability (HRV) might provide an index of relative sympathetic (SNS) and parasympathetic nervous system (PNS) activity during exercise. Eight subjects completed six 17-min submaximal exercise tests and one resting measurement in the upright sitting position. During submaximal tests, work rate (WR) was increased for the initial 3 min in a ramp fashion until it reached constant WRs of 20 W, or 30, 60, 90, 100, and 110% of the predetermined ventilatory threshold (Tvent). Ventilatory profile and alveolar gas exchange were monitored breath by breath, and beat-to-beat HRV was measured as R-R intervals of an electrocardiogram. Spectral analysis was applied to the HRV from 7 to 17 min. Low-frequency (0-0.15 Hz) and high-frequency (0.15-1.0 Hz) areas under power spectra (LO and HI, respectively) were calculated. The indicator of PNS activity (HI) decreased dramatically (P less than 0.05) when the subjects exercised compared with rest and continued to decrease until the intensity reached 60% Tvent. The indicator of SNS activity (LO/HI) remained unchanged up to 100% Tvent, whereas it increased abruptly (P less than 0.05) at 110% Tvent. The results suggested that (cardiac) PNS activity decreased progressively from rest to a WR equivalent to 60% Tvent, and SNS activity increased only when exercise intensity exceeded Tvent.

High-performance liquid chromatographic determination of 4,4'-methylenedianiline in human urine

A method is described for the determination of urinary 4,4'-methylenedianiline (MDA) by high-performance liquid chromatography (HPLC). MDA was extracted from hydrolyzed urine using C18 solid-phase extraction columns. The extract was analyzed by reversed-phase HPLC with electrochemical detection at a cell potential of 0.8 V. The method was very sensitive (detection limit 2.5 micrograms/l) and quantitation using 4,4'-ethylenedianiline as an internal standard correlated well with results by gas chromatography-mas spectrometry. Run-to-run precision (n = 25) averaged 8.9%. In analysis of more than 160 potentially exposed workers, MDA was detected in less than 20% of the urines and concentrations ranged up to 210 micrograms MDA per g of creatinine.

A prospective evaluation of a simplified captopril test for the detection of renovascular hypertension

Renovascular hypertension is potentially curable but of low prevalence. A previous retrospective study has demonstrated the use of a potentiated increase in plasma renin activity after captopril administration as a diagnostic test for renovascular hypertension; this requires two blood samples for plasma renin activity determination and three inclusive criteria for a positive test result. We applied this test prospectively to screen 100 hypertensive patients for renovascular hypertension. We evaluated 29 patients with renovascular hypertension; the remainder were diagnosed as having essential hypertension. In our patient population, a postcaptopril plasma renin activity of 5.7 ng of angiotensin per milliliter per hour (ngAl.mL-1.h-1) or greater had a 100% sensitivity and an 80% specificity for renovascular hypertension. An absolute increase in plasma renin activity with captopril of 4.7 ngAl.mL-1.h-1 or greater had a lower sensitivity of 90% and a specificity of 87%, whereas a fractional increase in plasma renin activity after captopril of 150% or higher had the lowest sensitivity of 69% and a specificity of 86%. A subgroup analysis of 38 patients who were receiving diuretic therapy demonstrated that the test sensitivity was unchanged but the specificity was reduced. In conclusion, a single postcaptopril plasma renin activity value of 5.7 ngAl.mL-1.h-1 or greater is a simplified screening test for renovascular hypertension, with excellent sensitivity and acceptable specificity. This test is well tolerated, inexpensive, and easy to perform.

Gallium scan in the diagnosis and treatment of renal malacoplakia

A middle-aged female was admitted with a presumptive diagnosis of pyelonephritis that failed to respond to conventional antibiotic therapy. Multiple investigations to define the etiology of the persistent fever and accompanying acute renal failure were negative. A gallium scan revealed intense uptake in the renal parenchyma. Percutaneous renal biopsy revealed malacoplakia. Six weeks of therapy with ciprofloxacin resulted in resolution of fever, improvement in the follow-up gallium scan, and reversal of the acute renal failure.

Renal transplantation: a 20-year experience at the University of Florida

Substantial gains have been made in both patient and graft survival during 20 years of transplanting kidneys at the University of Florida. The number of transplant recipients yearly has increased from six in 1966 to more than 100 in 1986. The use of immunosuppression reflects our evolving understanding of transplant immunology, with current morbidity and mortality rates considerably improved over those of the early years. This paper summarizes our transplantation experience over the past two decades.

Incidental and purposeful random donor blood transfusion. Sensitization and transplantation

We conducted a prospective study to gauge the frequency and degree of sensitization by transfusion and/or pregnancy in 797 candidates for first renal transplants. Sensitization was proportional to the number of blood transfusions. Multiple transfusions or a history of pregnancy without transfusions had similar effects on sensitization. The combination of transfusion and prior pregnancy resulted in sensitization of 1/3 of the candidates. Patients who were not sensitized and were accepted for 1-haplotype living-related donor grafts or first-cadaver donor grafts were transfused to receive a total of 5 units of packed red blood cells. Parous patients had an undue rate of antibody formation and alternate means of selecting and managing parous women are described. Nonparous candidates had a low rate of sensitization (8%) that did not prove an impediment to obtaining a transplant. Only 2% of prospective LRD graft recipients developed antibody against their intended donor. Transplant patients were generally managed with azathioprine and prednisone. One-haplotype LRD graft survival of protocol patients was 93.7% one year posttransplant, and 82.1% at 5 years. One-year CD graft survival was 77%. There was no reduction in graft survival when the interval between transfusion and transplantation exceeded one year. Random donor transfusion is effective in improving renal graft survival. Some recent multiinstitutional reports indicate a reduction or absence of the transfusion effect with current immunosuppression. Discarding blood transfusion as a preparation for transplantation may be ill-advised pending a prospective study.

Loss of corticomedullary demarcation on magnetic resonance imaging: an index of biopsy-proven acute renal transplant dysfunction

A prospective study of 19 cadaveric renal allograft recipients with suspected graft rejection was undertaken to compare the histological findings of the renal transplant biopsy with the results of magnetic resonance imaging (MRI). All 19 patients underwent a biopsy of the transplant allograft. Biopsy results included acute cellular rejection, acute vascular rejection, chronic vascular rejection (CVR), and acute tubular necrosis (ATN). Recipients of cadaveric renal allografts with normal function served as controls. The control showed distinct corticomedullary demarcation (CMD) on T1-weighted imaging. In contrast, CMD was absent or diminished in all the patients with suspected allograft rejection. Unfortunately, the loss of CMD did not correlate with a specific biopsy diagnosis. Patients with biopsy evidence of acute and chronic rejection or ATN demonstrated loss of CMD with similar image patterns. In conclusion, MRI is capable of detecting renal allograft dysfunction, but does not permit the determination of a specific cause.

Extracorporeal shock-wave lithotripsy: long-term complications

Of 148 patients who had extracorporeal shock-wave lithotripsy (ESWL) for renal lithiasis in 1984, 21 (14%) returned after 17-21 months for renal function tests (21 patients) and blood pressure determination (20 patients). Quantitative radionuclide renography showed a statistically significant (p = .048) decrease in the percentage of effective renal plasma flow (ERPF) to the treated kidney. Two of these patients had developed hypertension requiring treatment but became normotensive when given medication. In the other patients there was a statistically significant increase in both systolic (p = .0002) and diastolic (p = .015) blood pressures. Information about blood pressure was also obtained from an additional 71 (48%) of the 148 patients; of the total 91 patients (61%) in whom blood pressures were obtained, seven (8%) had developed sufficiently severe hypertension to require treatment beginning within 21 months after ESWL. Side effects of ESWL for renal lithiasis include hemorrhage, edema, and acute tubular necrosis of the kidney. This form of renal trauma is associated with an immediate decrease in renal function of the treated kidney, and this decrease may be permanent. ESWL is also associated with the onset of hypertension, which may occur immediately or be delayed by several weeks or months. Although the pathogenesis remains unknown, hypertension is an important complication of ESWL in about 8% of patients.

Late results of renal transplantation

A total of 315 (64%) of 491 primary cadaver and living-related donor transplants performed from 1975 through 1984 were still functioning at 24 months. These selected patients were examined further to assess the impact of several risk factors on late graft and patient survival. Black recipients, patients with underlying diabetes mellitus or hypertension, patients with poor renal function at 24 months, and recipients of cadaver grafts had significantly poorer long-term graft survival. Age greater than or equal to 40, diabetes or hypertension, poor 24-month function, and cadaver donor transplantation were associated with poorer long-term patient survival. Considerable improvement in graft survival at 24 months was seen in 1980-1984 compared with the earlier period, coincident with our adoption of routine pretransplant random donor blood transfusion. In contrast, long-term graft survival in patients with functioning graft at two years did not improve significantly over the same period. Although living-related donor transplants showed greater graft and patient survival than cadaver donor grafts by univariate analysis, no such advantage was demonstrated by multivariate analysis.

Chronic continuous PTH infusion results in hypertension in normal subjects

The factors responsible for the frequent occurrence of hypertension in patients with primary hyperparathyroidism have not been elucidated. Suggested mediators have included hypercalcemia, renal insufficiency, and increased plasma renin activity. However, experimental results have not been reported in any species that test the hypothesis that sustained hypertension in this clinical syndrome is due to consequences of parathyroid hormone (PTH) excess versus unrelated factors (e.g., primary hypersecretion of other hormones, NaCl sensitivity, genetic factors). Moreover, no systematic evaluation of the renin or adrenal cortical responses to chronic PTH excess has been reported in any species. Accordingly, the present studies assessed the effects of chronic (12 days) continuous intravenous b-(1-34) PTH infusion in normal human subjects (n = 4). PTH infusion resulted in persistent hypercalcemia and hypertension, reversible during a 4-8-day recovery period. Transient but significant increases in urinary tetrahydroaldosterone excretion and plasma cortisol concentration were observed as hypercalcemia and hypertension developed. No significant changes in plasma potassium concentration or plasma renin activity were observed, suggesting that hypercalcemia-induced transient hypersecretion of ACTH was responsible for both cortisol and aldosterone responses. The present results suggest that hypertension associated with clinical primary hyperparathyroidism results from either direct or indirect effects of PTH excess, per se, and requires neither the long-term consequences/complications of the clinical disorder (e.g., severe nephrocalcinosis, renal insufficiency) nor primary hypersecretion of additional hormones. These results are consistent with the hypothesis that hypercalcemia alone or in combination with at least permissive levels of PTH can generate short-term, but persistent (12 days) hypertension in human subjects and thus may be the initiating mechanism for hypertension in clinical primary hyperparathyroidism.

Long-term control of plasma calcitriol concentration in dogs and humans. Dominant role of plasma calcium concentration in experimental hyperparathyroidism

Despite great interest in the elevated circulating levels of calcitriol (1,25-[OH]2D) associated with the clinical syndrome of human primary hyperparathyroidism, the relative potencies of known and potential stimuli/suppressors of long-term calcitriol levels have not been evaluated in either clinical or experimentally induced hyperparathyroid states. Based on reports that aparathyroid animals exhibit suppressed plasma calcitriol concentration and that acute administration of parathyroid hormone (PTH) to both humans and experimental animals or to renal slices in vitro results in increased plasma calcitriol concentration/production rate, it might be predicted that a chronic experimental model of either hypercalcemic primary hyperparathyroidism or hypocalcemic secondary hyperparathyroidism would show increased plasma calcitriol concentration. Chronic alterations in plasma calcium concentration have not been implicated as modulating calcitriol levels in any species. Accordingly, we investigated the long-term response of plasma calcitriol concentration in states of sustained experimental primary and secondary hyperparathyroidism. Intact dogs (group I) undergoing continuous intravenous PTH infusion for 12 d developed sustained hypercalcemia and hypophosphatemia, and plasma calcitriol concentration decreased from 23 +/- 3 to 14 +/- 3 pg/ml (P less than 0.01). Subsequent chelator (EGTA)-induced chronic normalization of hypercalcemia during ongoing PTH infusion resulted in a large and sustained increase in plasma calcitriol concentration to supernormal levels, reversible during subsequent cessation of chelator infusion. In additional intact dogs (group II), chronic chelator-induced hypocalcemic secondary hyperparathyroidism resulted in a sustained increase in plasma calcitriol concentration despite hyperphosphatemia. In normal human subjects undergoing a 12-13-d continuous intravenous PTH infusion to result in sustained moderate hypercalcemia (12.0 +/- 0.2 mg/100 ml) and hypophosphatemia, plasma calcitriol concentration decreased significantly (P less than 0.01) as in group I dogs and was followed by reversal to normal levels in a recovery period. The present results provide strong evidence in both humans and dogs that during experimentally induced chronic PTH excess, alterations in plasma calcium concentration dictate the directional response of circulating calcitriol concentrations. The long-term potency of plasma calcium concentration as a modulator of calcitriol metabolism is sufficient to override opposing modulation by plasma phosphorus concentration and PTH.