Systematic Assessment of Pulmonary Artery Haemodynamics Using Wave Intensity Analysis

Purpose Currently best clinical practice for the investigation of pulmonary hypertension (raised pulmonary pressures) involves patients attending the catheter laboratory and catheters being passed under fluoroscopic guidance via the femoral vein to measure right heart pressures (and generally also via the femoral artery and aorta to measure left sided pressures). Wave intensity analysis using simultaneous pressure and flow measurements gives additional information about the upstream and downstream effects on haemodynamics, and we propose will lead to a more detailed assessment of the influences both causing and exacerbating pulmonary hypertension. Until recently it has not been possible to assess these effects formally: the standard technique measures only local pressure.

Design This protocol will involve passing catheters as per usual practice into the pulmonary arteries and aorta. A Combiwire (a standard pressure and flow measurement wire which has been available commercially and used worldwide for the past 5 years for making physiological measurements in the coronary arteries) will then be advanced approximately 1cm beyond the end of the catheter. Participants will have the usual clinical protocol of left and right heart catheterisation (and coronary angiography if clinically indicated) and the simultaneous pressure and flow measurements will be made in addition. Participants will also have noninvasive imaging (echocardiography and, if clinically indicated, cardiac MRI) and serum biochemical measures, as per usual clinical practice. They will also undergo cardiopulmonary exercise testing to assess their lung and cardiac capacity.

Recruitment The investigators will recruit patients with pulmonary hypertension from the National Pulmonary Hypertension Service who are awaiting right and left heart catheterisation studies as part of their routine diagnostic work up. Patients with normal pulmonary pressures will be recruited from patients who are on the waiting list awaiting routine cardiac catheterisation for the investigation of shortness of breath and chest pain. Recruitment will involve a discussion with the patient and printed material that the patient can refer to. They will be fully aware of the additional measurements being made, and no therapeutic promises will be made.

Development of Research Proposal Interventional cardiologists, pulmonary hypertension specialists, clinical scientists and basic scientists have been involved with the development of this protocol. All members have been involved in critiquing the proposal. The investigators have also consulted patients who have been involved in previous research conducted during angiography regarding the number of hospital visits and additional time required during the procedure for data collection.

Consent All patients will be consented for the study by the research Fellow who will be a Cardiology SpR (MBBS, MRCP) or Pulmonary Hypertension Specialist. She will be able to assess capacity and understand the ethical principles underpinning informed consent.