Date of Award

January 2012

Document Type

Open Access Thesis

Degree Name

Medical Doctor (MD)

Department

Medicine

First Advisor

Robert I. White

Subject Area(s)

Medicine, Medical imaging and radiology

Abstract

Patients with pulmonary arteriovenous malformations (PAVMs) are at risk for complications, hemorrhagic and neurological, and therefore require close follow-up.

The primary hypothesis of this project poses that the exercise stress test (EST) and 6-minute walk test (6MWT) are reproducible and reliable in patients with PAVMs. Secondarily, if these tests are shown to be reproducible, they may become a surrogate follow-up tool for patients with PAVMs after quantification with non-contrast CT and may replace contrast echocardiography in asymptomatic children under age 12.

Twenty-two patients with PAVMs, most of whom had hereditary hemorrhagic telangiectasia (HHT), participated in a Human Investigations Committee-approved protocol. Patients ranged from 9 to 74 years of age (mean 28) and had a broad spectrum of anatomic subtypes of PAVMs, including focal and diffuse. Standard 6MWT and cycle ergometry EST were both performed twice with adequate rest between tests. Heart rate (HR) and oxygen saturation were measured at the beginning and end of each test. Distance walked and maximum resistance were also recorded. The intraclass correlation coefficients (ri) at the end of 6MWT were as follows: HR (ri = 0.940; 95% CI = 0.863- 0.975), post test oxygen saturations (ri = 0.973; 95% CI = 0.933-0.989), distance walked (ri = 0.942; 95% CI = 0.867-0.975). The ris at the end of EST were as follows: HR (ri = 0.941; 95% CI 0.865-0.975), oxygen saturation (ri = 0.993; 95% CI 0.982-0.997), and maximum resis- tance (ri = 0.941; 95% CI 0.864-0.975). 6MWT and EST were reproducible measures of exercise capacity and oxygen saturation and are potential adjunct tests in the follow-up assessment for patients with PAVMs.

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