Portopulmonary Hypertension -A Little More Data

A recent study (E Echocahrd-Dugelay et al. JPGN 2015; 61: 346-54, editorial 268-9) provides a little more data on the rare condition of portopulmonary hypertension (POPH). Untreated POPH can lead to right-sided heart failure and death; a prompt diagnosis improves the chance for responding to treatment.

In brief, the authors reviewed their experience with 14 patients that were diagnosed with POPH between 1983-2009. The authors also reviewed the literature for a total of 98 patients.

Findings:

  • 0.5% of children with portal hypertension had POPH
  • 0.9% of children with end-stage liver disease awaiting liver transplantation had POPH
  • Congenital portosystemic shunts (CPSS) appeared to be a risk factor for POPH and were noted in 3 of their 14 cases as well as 22 of 98 cases overall.
  • In treated patients (n=42), five-year survival was noted to be 80%. Treatment included vasodilator therapy, closure of CPSS, or liver transplantation.
  • Hepatopulmonary syndrome (with hypoxemia) may precede POPH; this was reported in 6 of the 98 patients in this report

Dr. Ronald Sokol’s commentary noted that guidelines for timing/frequency of pulse oximetry testing and formal echocardiographic screening are needed but “challenging given the present body of evidence.”  He recommends screening all pediatric liver transplantation candidates who have cirrhosis and portal hypertension with pulse oximetry and echocardiography as well as those with clinical features of POPH (eg. syncope, shortness of breath, dyspnea).  For other patient populations, it remains unclear.

Bottomline (from the authors): “Detection of POPH at an early stage requires systematic screening at regular intervals by echocardiography in children with all causes of portal hypertension.” Unanswered questions:

  • how much portal hypertension is needed to merit screening?
  • how often should screening take place?

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Could you recruit your patients to climb a mountain for research?

Amazingly, a group of investigators enrolled 25 healthy climbers to determine how hypoxia affects the expression of iron transporters in the duodenal mucosa (Hepatology 2013; 58: 2135-62).

Methods: In a nonblinded, prospective study, blood and duodenal samples were taken at three timepoints: baseline (446 meters) and at 4559 meters two days later after a rapid ascent and then at day four while remaining at high altitude. 14 subjects received dexamethasone on day 2 to avoid high-altitude sickness. The duodenal biopsies were obtained by unseated transnasal small-caliber duodenoscopy.  Numerous other assays were checked as well.

Key finding: Hypoxemia was associated with a 10-fold increase in duodenal expression of divalent metal-ion transporter 1 and ferroportin 1 which promote iron intake.  In addition, there was decreased serum hepcidin levels.

Take-home message: Hypoxic conditions such as high-altitude quickly lead to an activation of changes that lead to compensatory erythropoeisis.

Related blog post: Help with hepcidin | gutsandgrowth