Intrathoracic Venous Stenosis and Occlusion
Any running blood access depends entirely upon unobstructed venous outflow to the heart and lungs. Occlusion can be due to different factors, some of which (physiologic compression by the arteries) should be left alone, and thus an accurate diagnosis is important. Just as with any stenosis in this environment, the high flow decreases the threshold for turbulence, which in turn can worsen the stenosis-so prompt intervention is highly beneficial. Imaging is obviously critical, and includes duplex ultrasound (of limited role in the thorax), IVUS, venography, CT venography, and/or MR venography. While the risk to benefit issues are more complex than in the arm, these patients often have unusually severe and/or bilateral problems, and “fighting for every inch of ground” is often needed. When evaluating a patient with central venous obstruction, several key goals should be kept in mind: ensuring durable hemodialysis access, mitigation of symptoms, maximization of future access options, minimization of central venous catheter reliance, and minimization of morbidity. Angioplasty works well as only soft tissue surrounds most of these structures. Primary stenting has not shown to be of benefit in most situations at this time, and is best reserved for recoil, rupture, or restenosis. If a lumen is not present, numerous options exist for recanalization, including blunt, sharp, and RFA-assisted in-line recanalization, along with “inside out” recanalization as a bridge to HeRO device placement.
