“Thromboembolic obstruction of the major pulmonary arteries due to unresolved pulmonary embolism [with pulmonary hypertension]” “intraluminal thrombus organization and fibrous stenosis or complete obliteration of pulmonary arteries… The consequence is an increased pulmonary vascular resistance resulting in pulmonary hypertension and progressive right heart failure.”
True incidence unknown 500-2500 pts per year, 0.1-0.5% acute PE survivors 2 prospective follow up studies of patients with acute PE: 44% had persistent pulmonary htn +/- RV dysfunction, 5.1% developed CTEPH 3.1% had CTEPH at 1 year, 3.8% at 2 years Up to 2/3 of patients with CTEPH have no history of acute PE
Risk factors: 223 patient study: Previous PE history large perfusion deficit younger age 78 patient study: Age>70 systolic pulmonary artery pressure >50mmHg at time of diagnosis Echo at 6 weeks accurately distinguished complete resolution from persistent pulmonary htn.
Low correlation between degree of obstruction and degree of pulmonary hypertension Hemodynamic progression is seen in absence of recurrent events Histopathologic evidence
“Two compartment pulmonary vasculature bed” – Braunwald and Moser, 1971 Non-obstructed arteries showed changes consistent with chronic pumonary hypertension Arteries distal to occlusion were normal
10-20% have anticardiolipin antibody Elevated factor VIII Chronic inflammatory disorders Myeloproliferative disorders Venticulo-atrial shunt Splenectomy Abnormal RBCs interaction with pulmonary arteries? Abnormal RBCs act as prothrombotic? Abnormal platelet activation?
May be asymptomatic months – years Physical exam findings Accentuated pulmonic component S2 Bruits over anterior lung fields Dyspnea/exercise intolerance, chest pain, presyncope, syncope late
LE Doppler V/Q scan CT angiogram Right heart catheterization Angioscopy MRA with contrast
Of segmental perfusion deficits on V/Q scan Pulmonary veno-occlusive disease Pulmonary capillary hemangiomatosis Fibrosing mediastinitis Pulmonary vasculitis Sarcomas of pulmonary arteries
Without treatment Pulmonary Arterial Pressure >40mmHg: 30% 5y survival PAP>50mmHg: 10% 5y survival In another study, >30mmHg: 10% survival
With Pulmonary Endarterectomy (+lifelong anticoagulation and IVC filter) 5-24% perioperative mortality overall, <5% at experienced centers In experienced centers, well-selected patients Near normalization of hemodynamics Substantial improvement in clinical symptoms
“… there is no degree of embolic occlusion within the pulmonary vascular tree that is inaccessible and no degree of right ventricular impairment or any level of pulmonary vascular resistance that is inoperable.” -- Jamieson et al, UCSD
Medicine Epoprostenol – prostacyclin infusion Sildenafil – phosphodiesterase-5 inhibitor Bosentan – endothelin receptor antagonist Balloon angioplasty Has been done successfully Still considered experimental Lung transplant For people with advanced small vessel disease without comorbidities that preclude surgery
Review of systems and careful physical exam are important! Chronic thromboembolic disease is uncommon, but not rare Chronic thromboembolism is a treatable cause of pulmonary hypertension V/Q scan still an important diagnostic tool “No 21 year-old should ever be short of breath.”