it is known that pulmonary hypertension ( ph ) might occur in patients with end - stage renal disease ( esrd ) maintained on long - term haemodialysis ( hd ) as indicated by the current clinical classification of ph ( 4th world symposium , dana point , california , 2008 ) . an estimated 40% incidence of ph was reported in esrd patients on chronic intermittent hd using an arterio - venous ( a - v ) access [ 2 , 3 ] . remarkably , kidney transplantation  whether the a - v fistula remained open or was surgically ligated this supports the hypothesis that ph in esrd results largely from non - haemodynamic factors which can be resolved by normalization of the hormonal and metabolic changes as well as improvement of the inflammatory status following immunosuppressive therapy . furthermore , surgical ligation / revision of an a - v fistula was reported to attenuate ph in patients on chronic hd therapy and after kidney transplantation [ 46 ] . however , it remains to be demonstrated whether it is possible to completely normalize haemodynamics ( in a kidney transplant recipient ) after surgical shunt ligation of an a - v fistula and this should be achieved by the use of gold - standard right heart catheterization ( rhc ) . we report on a 68-year - old caucasian female who presented with progressive hypoxic respiratory failure , recurrent pulmonary oedema , severe bilateral pleural effusions and shortness of breath worsening over the past few months ( nyha / who class iv ) . her past medical history revealed esrd that was treated with chronic intermittent hd from 1995 to 2004 , followed by cadaveric kidney transplantation 2004 . hd had been performed using a native a - v fistula between the left radial artery and the left basilic vein that had remained patent throughout her renal replacement therapy and had become severely aneurysmatic during her hd treatment . laboratory evaluation revealed a normal blood count , slightly elevated serum creatinine , moderately elevated liver enzymes and an n - terminal pro - brain natriuretic peptide ( nt - probnp ) of > 70 000 pg / ml . medication upon admission included mycophenolate mofetil , tacrolimus , prednisone , torsemide , metoprolol and enoxaparin . repeated chest radiographs during the hospital stay revealed progressive bilateral pleural effusions and bilateral enlargement of the central pulmonary vasculature . transthoracic echocardiography displayed a normal left ventricular ejection fraction , no signs of diastolic left ventricular dysfunction , dilated left and right atria , slight mitral and tricuspid valve regurgitation and a hypertrophic right ventricle , and there was no inspiratory collapse of the enlarged inferior vena cava . the results of the initial rhc after admission are summarized in table 1 . due to clinical worsening over a few weeks , a second rhc was performed ( table 1 ) . here , short - term ( 60 s ) external manual compression of the a - v fistula during rhc resulted in a reduction in cardiac output ( co ) from 5.7 to 3.8 l / min , suggesting a significant bypass volume . this corresponded well with an estimated flow via the a - v fistula of 2.6 l / min ( 46% of the co ) as assessed by duplex sonography . table 1findings from right heart catheterizationinitial assessmentprior to fistula closureafter fistula closureoxygen ( l / min)020haemoglobin ( g / dl)10.910.511.2heart rate ( bpm)918375systolic sap ( mmhg)122143150diastolic sap ( mmhg)597482mean sap ( mmhg)8699100systolic pap ( mmhg)618635diastolic pap ( mmhg)222812mean pap ( mmhg)364620rap ( mmhg)6174pawp ( mmhg)14138co ( l / min)7.05.74.2svr ( dyn  s  cm)91411511829pvr ( dyn  s  cm)251463229ci ( l / min / m)4.733.752.78tpg ( mmhg)223312pao2 ( mmhg)575476paco2 ( mmhg)344033sao2 ( % ) 928995svo2 ( % ) 817059ci , cardiac index ; co , cardiac output ; paco2 , arterial partial pressure of carbon dioxide ; pao2 , arterial partial pressure of oxygen ; pap , pulmonary artery pressure ; pawp , pulmonary artery wedge pressure ; pvr , pulmonary vascular resistance ; rap , right atrial pressure ; sap , systemic artery pressure ; sao2 , arterial oxygen saturation ; svo2 , mixed venous oxygen saturation ; svr , systemic vascular resistance ; tpg , transpulmonary gradient . findings from right heart catheterization ci , cardiac index ; co , cardiac output ; paco2 , arterial partial pressure of carbon dioxide ; pao2 , arterial partial pressure of oxygen ; pap , pulmonary artery pressure ; pawp , pulmonary artery wedge pressure ; pvr , pulmonary vascular resistance ; rap , right atrial pressure ; sap , systemic artery pressure ; sao2 , arterial oxygen saturation ; svo2 , mixed venous oxygen saturation ; svr , systemic vascular resistance ; tpg , transpulmonary gradient . based on the clinical findings and the rhc results , the decision was made to surgically ligate the a - v fistula . at a follow - up visit 3 months later , the patient presented without shortness of breath , no signs of hypoxia and a marked decrease in nt - probnp concentration from > 70 000 to 9778 pg / ml . the chest radiograph displayed only marginal residual bilateral pleural effusions with slight bilateral enlargement of the central pulmonary vasculature . a subsequent rhc revealed normalization of both mean pap and pulmonary vascular resistance ( pvr ) , as well as normal oxygenation breathing ambient air ( table 1 ) . based on the dana point ph classification , this case is best categorized in group 5 ( miscellaneous ) as an esrd patient maintained on long - term hd . however , this patient fulfils criteria for pulmonary arterial hypertension ( pah )   and the pathophysiological conditions with increased co due to systemic a - v shunting ( over a total of 16 years ) resemble those of patients with congenital systemic - to - pulmonary shunts ( group 1.3.2 . ) . in this context , the development of pah is associated with persistent exposure of the pulmonary vasculature to both increased blood flow and pressure , resulting in pulmonary obstructive arteriopathy that leads to an increase in pvr . our patient met several criteria for high - output cardiac failure , defined as symptoms of cardiac failure ( dyspnoea at rest , pulmonary oedema ) in the presence of a cardiac index above normal ( > 3.0 l / min / m ) . interestingly , unlike previous reports which suggested post - capillary ph in the presence of impaired left heart function with remarkably elevated pulmonary artery wedge pressures ( pawp ) [ 4 , 6 ] , rhc results suggested pre - capillary ph in our patient . however , pawp before shunt ligation reached borderline values which might further increase during physical exercise . this finding , along with results from echocardiography , makes the presence of ( diastolic and/or systolic ) left ventricular dysfunction very unlikely in this case . surprisingly , our patient presented with severe ph several years after successful kidney transplantation , suggesting that kidney transplantation per se does not necessarily prevent the abnormal haemodynamics associated with a - v access fistulas . ph in hd patients caused by an a - v fistula differs from other entities since it is ( at least partially ) reversible after correction of the increased co , suggesting that unlike in other types of ph , the pulmonary vasculature remains largely intact , and only undergoes minor remodelling in hd patients . it might be speculated that mainly the reduction in excessive pulmonary flow per se achieves the reduction in pap in these cases . however , this is challenged by the aforementioned observation that kidney transplantation has been reported to result in normalization of the haemodynamics even if the a - v access fistula remained patent . furthermore , if this assumption holds true , one would expect that elevated pap levels normalize in all cases following shunt ligation . this , however , is obviously not the case as discussed in the following paragraph . our case is unique since it is  to the best of our knowledge  the first to demonstrate severe ph in the presence of a - v fistula the complete normalization of haemodynamics after surgical shunt ligation ( unlike the case in which mean pap remained pathological with 28 mmhg and the a - v shunt was revised rather than ligated ) by the use of gold - standard rhc prior to and after surgical intervention rather than sole transthoracic echocardiography and additional surrogate parameters like in earlier reports [ 25 ] and presents on pre - capillary ph ( unlike cases in which pawp was notably elevated ) . as suggested by macrae et al . , we conclude that patients with persistent a - v fistulas ( after kidney transplantation ) should be carefully monitored for signs of ph and surgical shunt ligation / revision has the potential to avoid the considerable morbidity and mortality associated with this condition .
pulmonary hypertension ( ph ) occurs in end - stage renal disease ( esrd ) patients on long - term haemodialysis ( hd ) using an arterio - venous ( a - v ) access and can be attenuated by either kidney transplantation per se or surgical fistula ligation / revision . 
 we report an exceptional case with severe ph after kidney transplantation due to esrd and prior chronic intermittent hd via a patent a - v fistula . 
 gold - standard right heart catheterization findings have  for the first time  proven that following surgical shunt ligation of the a - v fistula , haemodynamics normalized completely in this patient .