Surgery for Chronic Thromboembolic Pulmonary Hypertension: Thromboendarterectomy of the Pulmonary Artery

Introduction

Chronic thromboembolic pulmonary hypertension (CTEPH) is caused by proximal pulmonary artery thromboembolic occlusion or obstruction. Patients present with shortness of breath, early fatigue, and decreased exercise capacity. Once the obstruction sets in, it is accompanied by remodeling of the branches of the pulmonary artery. This causes pulmonary artery hypertension and subsequently leads to right ventricular (RV) dysfunction, which eventually leads to RV failure [1]. The American Heart Association makes a class 1 recommendation that indicates CTEPH should be promptly evaluated for pulmonary endarterectomy, even if symptoms are mild [1].

Pulmonary thromboendarterectomy is a potentially curative surgery for CTEPH. The incidence is estimated to be between one and five percent among survivors of acute pulmonary embolism (PE) [2]. However, diagnostic data from echocardiography and computed tomography (CT) scans done when PE is first diagnosed suggest that many patients with CTEPH have undiagnosed pulmonary hypertension. This may indicate that the first clinical presentation of CTEPH may present as acute PE [3]. Apart from pulmonary embolism, hypercoagulable states may be the etiology of this disease.

Medical therapy is aimed at lowering the resistance of and pressure in pulmonary vessels. This includes vasodilators and drugs inducing remodeling of the vessels. It does improve symptoms such as exercise intolerance and oxygen desaturation. Medical therapy is not curative, and its effects are relatively modest [4]. Surgery is the only definitive therapy for CTEPH, and pulmonary thromboendarterectomy is the surgical procedure of choice.
Patient History

The authors present a case of CTEPH. The patient was a 35-year-old man presenting as an outpatient with complaints of severe progressive dyspnea. He was diagnosed with pulmonary embolism in the past and has been on anticoagulation for more than three years. He has had CT scans and chest x-rays in between. Multiple transthoracic echocardiograms have been performed with evidence of slowly declining right ventricular function. This time, he presented to the cardiac surgery service with a severely dilated and dysfunctional right ventricle. He had been on diuretics and vasodilator treatment but had mild to no improvement. After a thorough review, the authors decided to perform a pulmonary thromboembolectomy. The CT scan images show a dilated RV and intravenous contrast reflux in the inferior vena cava (Figures 1-4). The thrombus can be seen starting in the main pulmonary artery and almost completely occluding it. The thrombus extends into the bilateral pulmonary arteries.
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