| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
J Thorac Cardiovasc Surg 1998;115:473-474
© 1998 Mosby, Inc.
BRIEF COMMUNICATIONS |
Strasbourg, France
From Département de Physiologie, Faculté de Médecineand Service de Chirurgie Cardiovasculaire, Hôpitaux Universitaires,Strasbourg, France.
Received for publication July 3, 1997 Accepted for publication Sept. 23, 1997. Address for reprints: Bernard Geny, MD, PhD, Institut de Physiolgie,Faculté de Médecine, 67085 Strasbourg Cedex, France.
Brain natriuretic peptide (BNP), a recently discovered cardiac hormone,is secreted mainly by the cardiac ventricles and has potent diuretic,natriuretic, and vasorelaxant properties. Circulating BNP levels are increasedin patients with heart failure in proportion to the severity of the disease andmay have important compensatory renal, cardiovascular, and endocrinologicactions. Cardiac transplantation, a recognized treatment for end-stage heartfailure, normalizes the neuroendocrine balance, but atrial natriuretic peptideand BNP levels remain elevated in heart-transplant recipients.
1 Contrasting with the numerousstudies focused on atrial natriuretic peptide in heart transplantation 2 and despite the greater potentialbeneficial effects of BNP, few data are available concerning the BNP levelresponse to cardiac transplantation. 3,4
Method and results. Plasma BNP levelswere determined by radioimmunoassay with kits from Peninsula Laboratories(Belmont, Calif.) after extraction by Sep Pak C18 cartridges (WatersChromatography, Milford, Mass.) in 25 patients just before and daily during thefirst week after either heart transplantation (n =15) or coronary artery bypass grafting (CABG, n =10). Patients undergoing CABG served as a control group to differentiate anyhormonal effects of cardiac surgery per se from specific effects oftransplantation. Cardiovascular hemodynamics, plasma creatinine level (used asan index of renal function), endothelin level, and medications were measuredsimultaneously. The study was approved by the institutional review board, andeach patient gave informed consent.
Fig. 1 shows that plasma BNP level tended to decrease partially andtransiently after transplantation, in opposition to the increase observed afterCABG. Table I presents the beneficialhemodynamic effects of heart transplantation.CABG transiently increased the heart rate but did not modify the systemic bloodpressure; right ventricular hemodynamics were not determined. Serum creatininelevel, not modified after CABG, tended to increase after transplantation. Aspreviously reported, endothelin level increased progressively after operation. 2 Positive correlations were observedbetween systolic, diastolic, and mean pulmonary artery pressures and BNP level (r = 0.57, p = 0.01; r = 0.45,p = 0.04; and r =0.47, p = 0.04, respectively) andcapillary wedge pressure and BNP level (r =0.49, p = 0.03) when considering the acuteeffect of transplantation (day 0 and day 1). Among the usual first-weekchronotropic and inotropic drug support, only isoproterenol (INN: isoprenaline)and dopamine correlated with plasma BNP level in heart transplantation (r = 0.57, p <0.0001, and r = 0.23,p < 0.02, respectively). No significantcorrelation was observed between BNP level and azathioprine, prednisolone, orcyclosporine (INN: ciclosporin), but BNP level was positively correlated withserum creatinine and endothelin levels (r =0.60, p < 0.0001, andr = 0.55, p =0.002, respectively).
|
|
3 and increased plasma BNP levels wererecently reported to be associated with increased right ventricular afterload inheart transplantation. 4
Several factors acting on BNP clearance and secretion rates may explainwhy BNP level decreases only partially and transiently after transplantation.BNP is cleared by the kidney, and moderate renal failure, as inferred fromincreased creatinine level, may partially explain the secondary increase of thecardiac hormone. Endothelin may participate in BNP level elevation in hearttransplantation, both through its deleterious renal effects and through directstimulation of BNP secretion. BNP levels after cardiac transplantation may alsoreflect predominantly right and left ventricular diastolic function. 4 Indeed, BNP level is elevated inpatients with isolated diastolic dysfunction, 5 and it is well known that, inaddition to normalizing systolic function, heart transplantation results indiastolic dysfunction. This may explain the need for drug support and thepositive correlation observed between BNP level and isoproterenol. Althoughpositive correlation between BNP level and trough cyclosporine levels has notconsistently been reported, 3,4 it is tempting to speculate thatcyclosporine may participate in BNP level increase in our heart transplantationgroup, because BNP level increased when cyclosporine therapy was began (day 4).In this view, the lack of correlation between BNP level and cyclosporine in ourheart transplantation group may rely on the fact that peak levels or localtissue concentrations of cyclosporine, rather than 12-hour trough level, may bebetter for cyclosporine effect assessment.
In summary, an early determination of BNP level after transplantationallowed us to observe transient changes that might otherwise have been missed.The results suggest that hemodynamic improvement after heart transplantationreduces plasma BNP levels and that impaired renal function, increased endothelinlevel, and diastolic dysfunction increase the cardiac hormone early after hearttransplantation. Systemic hypertension, occurring later after transplantation,may then increase diastolic dysfunction, thus enhancing BNP secretion in hearttransplantation.
References
This article has been cited by other articles:
|
|
 |
|
  R. G. Masters, R. A. Davies, J. P. Veinot, P. J. Hendry, S. J. Smith, and A. J. de Bold Discoordinate Modulation of Natriuretic Peptides During Acute Cardiac Allograft Rejection in Humans Circulation, July 20, 1999; 100(3): 287 - 291. [Abstract] [Full Text] [PDF]
|
|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
,n = 10). For differences between patients undergoing heart transplantationand those undergoing CABG, asterisk indicatesp < 0.0001, daggerindicatesp = 0.03, and doubledagger indicatesp < 0.0001. The dottedlines show the 95% range of variation of normal valuesobtained in healthy subjects.