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Supine Exercise in Hepatopulmonary Syndrome Patients With Orthodeoxia

Hepatopulmonary Syndrome

Hepatopulmonary syndrome (HPS) is a rare condition that presents in about a quarter of patients with liver cirrhosis. In addition, a small subset of these HPS patients also have orthodeoxia, defined as a drop in oxygen levels when they are sitting up (upright), as opposed to lying flat (supine). At present, there is little known about this condition. Patients diagnosed with HPS and orthodeoxia experience reduced ability to exercise, especially when upright. While standard cardiopulmonary exercise is routinely performed in the sitting position, there are machines that enable candidates to exercise in the supine position. This is especially relevant in patients with severe HPS, with clinically significant orthodeoxia, where conventional upright exercise is difficult. Currently there is a gap in the literature regarding the efficacy of supine exercise compared to upright exercise in these patients. Due to their improvement in dyspnea when lying supine, it is predicted that these patients will be able to exercise for a greater length of time and have increased exercise capacity, which can be projected to improve outcomes pre- and post-transplant.

Overall, HPS patients tend to experience hypoxemia and exercise limitation. Exercise limitation impacts quality of life, incidence and severity of comorbid conditions, and in those who are liver transplant candidates, low exercise tolerance deleteriously impacts transplant outcomes. Accordingly, a strategy that enables patients to exercise more often and/or for longer periods would offer direct benefits to patients with HPS, and if employed as part of an exercise program, could also improve exercise capacity, and thus, liver transplant outcomes.

The purpose of this study is to investigate the effect of supine, compared to upright position on exercise in patients with HPS and orthodeoxia. We hypothesize that these patients will be able to exercise for longer in the supine compared to the upright position, given improved oxygen levels when supine.

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Participation Requirements

  • Sex:

    ALL

  • Eligible Ages:

    0 and up

Participation Criteria

Inclusion Criteria:

1. Diagnosis of moderate HPS (defined by liver disease, hypoxemia \[PaO2 \< 80 mmHg and AaDo2 (alveolar-arterial PO2 difference) ≥ 15 mmHg or ≥ 20 mmHg if age \> 64 years\] and IPVD (intrapulmonary vasodilatations) as shown by contrast echocardiography\])
2. Presence of orthodeoxia (PaO2 decrease by \>4 mmHg when patient moves from supine to upright position).

Exclusion Criteria:

1. Pulmonary hypertension (echocardiographic estimated right ventricular systolic pressure \>/=50 mmHg and/or right heart catheterization mean pulmonary artery pressure \>25 mmHg with pulmonary capillary wedge pressure \</= 15 mmHg);
2. Significant obstructive ventilatory impairment (FEV1/FVC ratio \< 0.65) (FEV=forced expiratory volume in 1 second; FVC=forced vital capacity)
3. Known significant coronary artery disease;
4. Significant neurologic, orthopedic or rheumatological disorders preventing the use of a cycle ergometer;
5. Other absolute contraindications to submaximal tests (uncontrolled cardiac arrhythmia with hemodynamic compromise, symptomatic severe aortic stenosis, decompensated heart failure and acute cardiopulmonary illness);
6. Moderate or severe ascites.

Study Location

St. Michael's Hospital
St. Michael's Hospital
Toronto, Ontario
Canada

Contact Study Team

Primary Contact

Samir Gupta, MD, MSc

[email protected]
(416) 864-6060
Study Sponsored By
Unity Health Toronto
Participants Required
More Information
Study ID: NCT04004104