Figure 5

Alternative pathways for pulmonary arteriovenous malformation (PAVM) diagnosis. a) Usual pathway for symptomatic patients presenting to general respiratory services. b) Pathway recommended by international patient guidelines using contrast echocardiography (echo) as a first-line screen [74]. c) The standard 2011 pathway used at Imperial College London, UK (HHTIC London). d) 2011 HHTIC London option for individuals requesting a first-line echocardiogram. Pre-echocardiography oxygen saturations and chest radiography allows avoidance of contrast echo in patients who are significantly desaturated and most likely to get symptoms (usually migraine/aura) after contrast echocardiography, because they will have masses of bubble emboli. (If symptoms occur, immediate 100% oxygen will get rid of the bubbles and symptoms quickly.) Sa,O2: arterial oxygen saturation; CT: computed tomography.