PAVMs, exercise, and airflow obstruction

• Research type

  Research Study

• Full title

  Hypoxaemia, dyspnoea, and exercise tolerance in patients with pulmonary arteriovenous malformations- influence of coexisting irflow obstruction

• IRAS ID

  176983

• Contact name

  Claire Shovlin

• Duration of Study in the UK

  4 years, 0 months, 0 days

• Research summary

  The lung is the site at which oxygen enters the blood stream, diffusing from the alveolar air sacs into the pulmonary capillaries. This newly oxygenated blood is carried to the heart in the pulmonary veins, then passes into the systemic circulation to provide oxygen to the tissues.

  Patients with pulmonary arteriovenous malformations (PAVMs) have abnormal vascular connections between pulmonary arteries and veins in the lung that bypass the oxygenation sites in the pulmonary capillaries.

  Low blood oxygen tension (hypoxaemia) is frequent in PAVM patients but breathlessness (dyspnoea) is not. Many patients are performing competitive sports with oxygen level below those for which home oxygen therapy would normally be recommended. Our previous studies have shown that low oxygen levels do not correlate with dyspnoea in the population; that treatment of PAVMs by embolization does not usually improve exercise capacity; and illuminated mechanisms that allow patients to achieve this.

  However, patients who did report improvement in exercise tolerance after embolization, tended to have mild asthma, COPD or other conditions that led to higher blood pressure in the lungs.

  In this study we will use standardised cardiopulmonary exercise testing to examine why hypoxaemic PAVM patients with asthma or other respiratory conditions are more dyspnoeic pre treatment.

  We will address this by performing standardised cardiopulmonary exercise testing, as used in the clinic, on age and sex matched patients with PAVMs with and without concurrent respiratory conditions such as asthma and COPD.

  As in our earlier studies, physiological parameters will be compared, to test the null hypotheses first, that the impact of exercise on PAVM patients' cardiopulmonary systems does not differ in the setting of asthma or COPD, and second, whether responses to embolization differ by restudying after PAVMs have been treated by embolization.

  Finally, cellular and molecular methods will be used to dissect mechanistic pathways.

• REC name

  London - West London & GTAC Research Ethics Committee

• REC reference

  15/LO/0598

• Date of REC Opinion

  28 Apr 2015

• REC opinion

  Further Information Favourable Opinion