Cardiopulmonary Exercise Testing Demonstrates Maintenance of Exercise Capacity in Patients With Hypoxemia and Pulmonary Arteriovenous Malformations

The Lung in Hereditary Hemorrhagic Telangiectasia

“…The most striking clinical finding in this patient group is the presence of asymptomatic hypoxemia [49] : significantly hypoxemic patients with SaO 2 <85% are often able to pursue sporting activities to a very high level [50] , emphasizing the powerful hematological [49,51] and hemodynamic [52,53] compensatory responses that can be employed. Crucially, these compensatory responses are then lost after treatment of PAVMs, and exercise capacity/oxygen delivery usually returns to pretreatment levels [49,51,53] .…”

“…Crucially, these compensatory responses are then lost after treatment of PAVMs, and exercise capacity/oxygen delivery usually returns to pretreatment levels [49,51,53] . There is no clear relationship between the severity of right-to-left shunting and dyspnea; instead dyspnea appears to be more common in patients with airflow obstruction related to another condition, higher pulmonary artery pressures, anemia, or other indices of ill health [49,52] .…”

“…Interventional treatment is thus warranted in all patients with PAVMs of a size amenable to treatment, irrespective of symptoms [49,61,[78][79][80] . PAVM treatment also reduces migraines [61,81] , HHT nosebleeds [82] , polycythemia [49,51] , and hemodynamic sequelae of PAVMs [52,53] . Patients should not undergo embolization expecting improved exercise tolerance, although this may be observed.…”

“…There is no rationale for prophylactic oxygen use to prevent hypoxic PH, because there is no alveolar hypoxia [52,54] .…”

Pulmonary Arterio-Venous Malformation (PVAM) Presenting as Recurrent Hemoptysis

“…Even the work capacity is well preserved in patients with PAVM even when arterial oxygen saturation drops to less than 80% on exercise. [11] Complications: Pulmonary hypertension is believed to be common in PVAM because of high blood flow in pulmonary circulation but actually overall prevalence of pulmonary hypertension is relatively low. In one echocardiographic study of 68 HHT patients , estimated systolic PPA values (40 to 58 mm Hg) were above the normal range in 9 (20.5%).…”