Plasma atrial natriuretic factor and graft function in renal transplant recipients

In order to determine the relationships between allograft function and the recipient's plasma concentrations of atrial natriuretic factor (ANF), plasma ANF was measured by radioimmunoassay for 14 days after cadaveric renal transplantation in 9 patients aged 19-64 years. All received immunosuppression with prednisolone, azathioprine, and cyclosporine. No patient was in heart failure. During the study period, six grafts functioned, and three were nonfunctioning--two due to rejection and one to acute tubular necrosis. Plasma ANF concentration at the time of transplantation was 48 +/- 16 pmol/L (mean +/- SEM) range 15-145 pmol/L. In the six patients with functioning grafts, ANF declined in parallel with the fall in serum creatinine (658 +/- 35 to 210 +/- 34 mumol/L). In the three with nonfunctioning grafts, serum creatinine and plasma ANF concentration both increased. There was overall a significant linear relation between serum creatinine and plasma ANF (r = 0.527, P less than 0.001). The changes in plasma ANF after renal transplantation bore no relationship to changes in body weight or blood pressure. However, plasma ANF concentration was related to allograft fractional sodium excretion (r = 0.687, p less than 0.001). We conclude that elevated plasma ANF concentrations in end-stage renal disease are restored to normal by successful renal transplantation, implying that renal function is a determinant of plasma ANF concentration. Circulating plasma ANF may also have a direct effect on allograft sodium excretion.     

N-terminal fragments of the proatrial natriuretic peptide in plasma and urine of kidney graft recipients

BACKGROUND: Successful kidney transplantation normalizes elevated proatrial natriuretic peptide (proANP) plasma concentrations of renal failure patients in the early posttransplant period. We evaluated plasma and urinary proANP fragments in the late posttransplant period. METHODS: Immunoreactive proANP(1-30) and proANP(31-67) were determined in 389 renal transplant (Rtx) recipients in the long-term, follow-up period and in 16 healthy controls. RESULTS: Rtx recipients had significantly higher concentrations of proANP(1-30) and proANP(31-67) in both plasma and urine than healthy controls. Although their graft function was normal, all of these long-term Rtx recipients were taking glucocorticoids, which increase proANP(1-30) and proANP(31-67) in the circulation to the extent found in this investigation. Two-thirds of these recipients were also taking cyclosporine, which also increases atrial peptides. Urinary proANP(31-67) was significantly higher than urinary proANP(1-30); 5.5-fold in Rtx patients and 2-fold in controls. Deterioration of renal graft function was associated with a rise of plasma proANP(1-30) from 0.98+/-0.66 to 6.28+/-3.55 nmol/l (P<0.0001) and plasma proANP(31-67) from 1.81+/-1.04 to 7.89+/-3.76 nmol/l (P<0.0001). Urinary excretion of proANP(1-30) increased from 0.27+/-0.34 to 5.96+/-5.07 nmol/24 hr (P<0.0001) and proANP(31-67) from 1.45+/-0.85 to 12.23+/-5.12 nmol/24 hr (P<0.0001). Also proteinuria enhanced plasma and urinary proANP fragments. CONCLUSIONS: ProANP(1-30) and proANP(31-67) of Rtx recipients are affected by immunosuppression, hypertension, renal failure, and proteinuria. One would have expected proANP(1-30) and proANP(31-67) not to normalize because of the glucocorticoids that they were receiving.     

Plasma concentration and urinary excretion of N-terminal proatrial natriuretic peptides in patients with kidney diseases

BACKGROUND: Biologically active N-terminal fragments such as proANP(1-30), proANP(31-67), and proANP(1-98) derive from the prohormone of alpha-human atrial natriuretic peptide [proANP(99-126) or alpha-ANP]. No systematic data are available for patients with different kidney diseases. METHODS: Specific immunoassays were developed to determine plasma and urine concentrations of these fragments in 121 patients with different degrees of kidney function and urinary protein excretion, respectively. RESULTS: In patients with kidney disease and normal renal function without proteinuria, circulating proANP(1-30) and proANP(31-67) increased 2.8-fold and 6.5-fold, respectively. Urinary excretion of proANP(31-67) increased by a factor of 7.7 in these patients, whereas proANP(1-30) was not affected. Patients with impaired renal function had a dramatic increase of urinary proANP(31-67) excretion even before serum creatinine levels started to rise. The progression of renal failure caused a significant rise of circulating proANP(1-30) (4.3-fold) and proANP(31-67) (3.0-fold) compared with patients with normal renal function. Urinary excretion of proANP peptides significantly increased, particularly when the serum creatinine level was> 5.0 mg/dL [proANP(1-30) 26-fold, proANP(31-67) 8.4-fold]. Urinary excretion of proANP(1-30) increased up to 4.4-fold and urinary excretion of proANP(31-67) increased up to 2.4-fold in patients with proteinuria in excess of 3 g/24 h. CONCLUSIONS: Plasma concentrations and urinary excretion of proANP(1-30) and proANP(31-67) are affected by kidney disease and function, but not by proteinuria per se. It is proposed that the diseased kidney increases early urinary excretion of proANP fragments to participate in the regulation of renal function as well as sodium and water excretion.     

Pitfalls in the interpretation of pulmonary capillary wedge pressure

The measurement and interpretation of pulmonary capillary wedge pressure (PCWP) is often vital to the correct management of patients. In this article some pitfalls associated with PCWP measurement are discussed. The physiology of PCWP preload and the Starling curve are described. PCWP indirectly measures left ventricular end-diastolic volumes: the interpretation of this correlation is altered under certain circumstances, and these are described.     

Monitoring arterial,central venous and pulmonary capillary wedge pressure

Arterial blood pressure can be monitored non-invasively by mercury manometer, automated oscillotonometer or continuously by a Finapres based on the Penaz technique. Insertion of a cannula into an artery allows continuous beat-to-beat blood pressure monitoring with pressure transmitted along a column of saline to a piezo-resistive strain gauge transducer. Continuously monitoring blood pressure aids optimization of adequate organ perfusion and further information gained from the waveform can be used to guide treatments. Central venous pressure is the pressure within the right atrium and great veins of the thorax. In a healthy adult, it is between 0 and 8 cm H₂O, varying with respiration. It is measured via a cannula inserted into the superior vena cava (usually via internal jugular or subclavian veins) and uses a pressurized transducer set to produce a reading of central venous pressure and venous waveform. Venous bloods and central venous gases can also be taken and drugs and infusions (particularly if irritant) can be administered. Serial readings are useful for assessing progress and response to treatment. Pulmonary capillary wedge pressure represents left atrial filling pressure and therefore left ventricular end-diastolic pressure and allows more accurate assessment of left-sided heart function. It is measured by floating a pulmonary artery catheter and wedging a balloon into a pulmonary artery branch. It has a complication rate of 10% and, as studies have shown it to have no clear evidence of benefit, alternative less invasive methods such as oesophageal Doppler or arterial pulse contour analysis are now common alternatives.     

Color M-mode Doppler for postoperative estimation of pulmonary capillary wedge pressure

OBJECTIVE: The aim of this study was to evaluate the accuracy of the combined index E/Vp (peak E velocity combined with color M-mode color Doppler flow propagation) for estimating pulmonary capillary wedge pressure, in post cardiac surgery patients. STUDY DESIGN: Prospective clinical trial. PATIENTS AND METHODS: In post cardiac surgery patients (D1), we have measured with transthoracic echocardiography peak early E transmitral pulsed Doppler velocities and color M-mode Doppler flow propagation velocity (Vp). The E/Vp ratio was compared with pulmonary capillary wedge pressure (PAPO) obtained simultaneously. RESULTS: Thirty eight patients were studied. The coefficient of correlation between PAPO and E/Vp was r = 0.71 (p < 0.0001). The sensitivity and the specificity of E/Vp > 1.5 for prediction of PAPO > 15 mmHg were 79% and 79% respectively. CONCLUSION: In post cardiac surgery patients, PAPO can be reasonably estimated by measuring the ratio E/Vp obtained with Doppler echocardiography.     

N-terminal fragments of the proatrial natriuretic peptide in patients before and after hemodialysis treatment

BACKGROUND: Fragments derived from the prohormone of alpha-human atrial natriuretic peptide (alpha-ANP) in patients with cardiac failure are more closely related to the disease state than intact alpha-ANP. METHODS: Specific immunoassays have been developed to detect proANP 1-30, proANP 31-67, and proANP 1-98. Plasma concentrations of these fragments were determined in 122 hemodialysis patients with and without cardiac dysfunction, with and without hypertension, as well as with and without dialysis-associated hypotensive episodes either before or after a regularly scheduled hemodialysis session. The effects of different dialyzer membranes were also evaluated. The results of these assays along with other markers of volume regulation such as alpha-ANP and cyclic 3',5' guanosine monophosphate (cGMP) were compared with those of healthy controls. RESULTS: Predialytic and postdialytic plasma concentrations of the proANP fragments were markedly higher in uremic patients than in controls (98-fold for proANP 1-98, 56-fold for proANP 31-67, and 35-fold for proANP 1-30). All proANP fragments, alpha-ANP, and cGMP decreased during hemodialysis. A strong linear correlation was found between predialytic and postdialytic plasma levels. There was no correlation, however, with the amount of fluid removed during hemodialysis. Patients with altered left ventricular hemodynamics displayed significantly higher plasma concentrations of all proANP fragments and alpha-ANP, but not cGMP, than patients with normal cardiac function. Hemodialysis patients with moderate or severe hypertension had higher concentrations of proANP fragments, alpha-ANP, and cGMP than patients with normal blood pressure or patients with only mild hypertension. There was no significant difference in circulating levels of proANP peptides, alpha-ANP, and cGMP between patients with and without frequent dialysis-associated hypotensive episodes. Cellulose-triacetate dialyzers reduced plasma levels of proANP 1-30, proANP 31-67, and proANP 1-98 significantly more than polysulfone dialyzers, but alpha-ANP and cGMP levels were not different. CONCLUSIONS: Circulating alpha-ANP and proANP fragments are influenced by a variety of factors such as end-stage renal disease, hemodialysis treatment, dialyzer membrane material, cardiac dysfunction, and hypertension. Therefore, these are not useful markers to accurately estimate volume status in hemodialysis patients.     

A new method of predicting pulmonary capillary wedge pressure: the arterial pressure ratio

The response of arterial blood pressure to an increase in intrathoracic pressure has been shown to be predictive of pulmonary capillary wedge pressure. We devised a new method, which we termed the arterial pressure ratio. We defined arterial pressure ratio as the ratio of systolic blood pressure of the final beat during the strain phase of the Valsalva manoeuvre to that during apnoea before the manoeuvre, and tested the accuracy of arterial pressure ratio in predicting pulmonary capillary wedge pressure. In 30 patients scheduled for elective abdominal aortic reconstruction, following induction of general anaesthesia and tracheal intubation, a 20-G catheter and pulmonary artery catheter were inserted through the radial artery and right internal jugular vein, respectively. Pulmonary capillary wedge pressure was then measured during a brief period of apnoea and the Valsalva manoeuvre was performed by application of pressure to the reservoir bag. Airway pressure was maintained at 30 cmH2O for 10 s and then released. Radial arterial pressure and airway pressure were recorded simultaneously, and arterial pressure ratio was calculated. There was a close linear correlation between arterial pressure ratio and pulmonary capillary wedge pressure (r = 0.88, p < 0.0001).     

The relationship between central venous pressure and pulmonary capillary wedge pressure during aortic surgery

Twenty-three ASA physical status II-III patients scheduled for elective abdominal aortic surgery were studied preoperatively with multiple unit gated acquisition angiography (MUGA) scan to determine the resting left ventricular and right ventricular ejection fractions (LVEF and RVEF respectively). Intraoperatively pulmonary capillary wedge pressure (PCWP) and central venous pressure (CVP) were measured in each patient at five different time periods in the horizontal, 24 degrees head up, and 24 degrees head down table tilt positions. The correlation between absolute values and changes in PCWP and CVP, and the degree to which preoperative knowledge of LVEF and RVEF predicted these correlations were examined. Resting LVEF ranged from 0.1 to 0.84. Thirteen of the 23 patients failed to show significant correlation (p less than 0.05) between the absolute values of PCWP and CVP either before and/or after aortic crossclamp. When the correlation coefficients from this analysis were ranked against LVEF, there was a weak but significant correlation before aortic crossclamp (r = 0.41), but not after. The correlation between a change in PCWP and a change in CVP was significant for the 23 patients at all time intervals, before and after aortic crossclamp. However, the prediction of a change of PCWP value from a known change of CVP value ranged in accuracy from +/- 3 mmHg to +/- 12.5 mmHg. The study suggests that if the filling pressures of both ventricles need to be assessed during aortic surgery, then the PCWP and CVP must be independently measured.(ABSTRACT TRUNCATED AT 250 WORDS)     

动脉压力波与脉搏血氧饱和度波形预测肺小动脉楔压的研究

目的通过动脉压力波或脉搏血氧饱和度波形估测肺小动脉楔压(PAWP).方法14例择期腹部肿瘤手术的成年患者于全麻气管插管后,行术前急性高容量血液稀释,在输入10ml·kg-1液体、20ml·     

Plasma adiponectin in heart transplant recipients

Abstract: Background: The association between plasma adiponectin and metabolic syndrome may be impaired in heart transplant recipients, since renal failure is frequent among these patients. Thus, we studied the relationship between metabolic syndrome and plasma adiponectin in transplanted heart recipients. Methods: Ninety‐five heart transplant recipients were prospectively included 8.3 ± 5.6 yr after transplantation in this cross‐sectional study. All patients had physical examination, echocardiography or routine biennial coronary angiography, and laboratory measurements. Results: Metabolic syndrome was found in 31% of these patients. Plasma adiponectin was significantly lower in patients with metabolic syndrome (12.5 ± 8.3 μg/mL) than in patients without (16.7 ± 9.4 μg/mL, p = 0.03). Adiponectin levels were usually in the normal or high range (< 4 μg/mL in only two patients). Low creatinine clearance was associated with higher plasma adiponectin (R=?0.26, p = 0.01). Plasma adiponectin was not significantly different between the 28 patients with angiographic evidence of graft vasculopathy (13.9 ± 9.5 μg/mL) and the 67 patients without (16.1 ± 9.1 μg/mL, p = 0.3). Conclusions: Contrasting with a high frequency of metabolic syndrome in these patients, adiponectin levels were usually in the normal or high range, probably as a consequence of renal failure. This suggests that adiponectin is not a major determinant for insulin resistance among these patients.     

The accuracy of transoesophageal echocardiography in estimating pulmonary capillary wedge pressure in anaesthetised patients

The objective of this study was to identify whether pulmonary capillary wedge pressure can be estimated in anaesthetised patients receiving mechanical ventilation, using transoesophageal echocardiography. A retrospective validation study investigated a 10-patient cohort with variable haemodynamic conditions, and a 102-patient series in which a single measurement was made during stable haemodynamic conditions. Concurrent echocardiographic Doppler and pulmonary artery catheter wedge pressure measurements were performed. In the 10-patient cohort, the systolic fraction of Doppler measurements in the pulmonary vein (r = -0.32, p = 0.035) and the E/A ratio (r = 0.56, p = 0.0009) were correlated with the wedge pressure. In all cases, the limits of agreement exceeded 10 mmHg, and sensitivity or specificity for detecting wedge pressure ≥ 15 mmHg was poor. This study demonstrates proof of concept that using transoesophageal echocardiography for estimating the pulmonary artery wedge pressure may not be sufficiently accurate for clinical use.     

Malignant neoplasms in cardiac transplant recipients

Purpose: Heart transplant recipients have an increased risk of posttransplantation lymphoproliferative disorders (PTLD) associated with monoclonal antilymphocyte (OKT₃) immunosuppression and Epstein-Barr viral (EBV) infections. These studies were undertaken to determine whether polyclonal antilymphocyte therapy can reduce the incidence of malignant neoplasia.Methods: We reviewed our experience with polyclonal induction therapy to assess the risk of malignant neoplasms in 223 transplant recipients between April 1985 and September 1998. Posttransplant immunosuppression therapy employed either polyclonal antilymphocyte or antithymocyte globulin given as 10mg/kg/day in divided doses for 3 days followed by cyclosporine, azothioprine, and steroids. OKT₃ was used in only 2 patients for persistent rejection.Results: Twenty-nine patients developed invasive malignant neoplasms (a mean of 57.9 months posttransplant; range 7 to 125). Invasive malignancies included carcinoma of the lung (7 patients), colon (3), kidney (3), bladder (2), prostate (1), squamous cell carcinoma of the tongue (1), malignant melanoma (2), Kaposi’s sarcoma (1), and squamous cell carcinoma of the anus (1). Five patients developed lymphoma: 3 patients had PTLD, 2 patients had Hodgkin’s and non-Hodgkin’s lymphoma. Positive EBV IgG titers (>4:1) were found in 3 patients, but only 1 of these developed PTLD and none of these patients received OKT₃. Of the 29 patients with invasive malignancy, 13 (45%) died secondary to their malignancy; 5 died of unrelated causes (sepsis, myocardial infarction, and organ failure); and 11 are alive after surgical excision and/or chemotherapy. The age-adjusted incidence of invasive neoplasm was 7.33 (95% 5.95 confidence interval 8.09) times as great as rates for the general population in the State of Michigan between 1988 and 1995.Conclusion: While induction polyclonal antilymphocyte therapy may reduce the risk of PTLD, the incidence of posttransplant malignancy remains high. A vigilant cancer surveillance protocol is mandatory in these high-risk patients.     

The use of Opticath in the correct measurement of the pulmonary capillary wedge pressure]

The Authors assess the utility of the on-line monitoring of SvO2 during 156 measurements of pulmonary capillary wedge pressure (PCWP) done on 52 Intensive Care Unit patients. The measurement was always right when the SvO2 increased more than 90%. The Authors found a good correlation between the SvO2 monitored during the measurement of the PCWP and the saturation of pulmonary capillary blood measured by cooximeter. These data suggest that the complex procedure to confirm the reliability of the measurement recommended by Gardner can be simplified by the observation of the trend of SvO2 on the monitor oximetrix. This allows to obtain saving time for the staff, saving blood for the patients, reduction of risk for the transmission of infective diseases due to the handling of blood and guarantees a further routinary control of reliability on the measure of PCWP.     

Shape and movement of the interatrial septum predicts change in pulmonary capillary wedge pressure.

We aimed to assess whether movement of the interatrial septum predicts change in pulmonary capillary wedge pressure (PCWP). In 71 patients undergoing cardiac surgery, the interatrial septum was categorised by its shape and movement using transesophageal echocardiography. Fixed curvature (FC) was identified by bowing of the interatrial septum from left to right throughout the cardiac cycle, mid-systolic reversal (MSR) by minimal septal movement and transient reversal (right to left) during mid-systole, and mid-systolic buckling (MSB) by marked movement and buckling of the septum during mid-systole. These were compared with PCWP. Sensitivity and interobserver reliability was studied with continuous PCWP and TEE measurement during a period of acute volume alteration in 10 additional patients. Interatrial septal movement predicted PCWP, with mean PCWP (95% confidence intervals) for FC, 18.1 mmHg (16.7 to 19.6), MSR 13.2 mmHg (12.5 to 13.8) and MSB, 9.9 mmHg (9.0 to 10.7) mmHg. The mean PCWP at which a change in pattern occurred was 8.9 mmHg (8.3 to 9.6) for MSR to MSB, and 10.9 mmHg (10.1 to 11.8) for MSR to FC (p<0.001). There was no significant difference in mean values for all three observers. Movement of the interatrial septum predicts change in PCWP.