Evaluation of Variability of Echocardiographic Estimates of Pulmonary Arterial Hypertension in Dogs

Purpose

This study addresses the hypothesis that echocardiographic variables commonly used in the non-invasive assessment of pulmonary hypertension in dogs are influenced by recording and measurement variability, sedation, stress, and exercise.

Background


Pulmonary hypertension is a common clinical abnormality in dogs associated with clinical signs including but not limited to coughing, exercise intolerance, weakness, fainting or passing out, and right-sided congestive heart failure contributing to poor outcome. Therefore, fast and reliable determination of pulmonary hypertension is of great clinical importance. Doppler echocardiography  (DE),  in  particular   tricuspid   regurgitation   (TR)-based   DE  pressure estimates,  are  the  clinical  gold  standard   method   in  the  non-invasive estimation of pulmonary  artery  pressure  (PAP)  but  are  subject  to  a  variety  of  independent  factors influencing  their  accuracy.  Recording and measurement error as well as effects of physiologic stressors have all been identified as independent factors leading to inaccurate pressure   estimates.   Although   knowledge   on   principal   components   influencing   DE hemodynamic   estimates   are well known   and   have been   applied   to   a variety   of echocardiographic variables used in the assessment of cardiac function over the past 40 years, variability of DE indices of PH has never been studied in people, dogs, or cats. This is  surprising  as  such  estimates  provide  relevant  clinical  and  prognostic   information. Moreover, effective treatments for PH became recently available, and DE has been used repeatedly in the evaluation of treatment efficacy.  We hypothesized that DE methods used in the assessment of PH are affected by a variety of independent factors causing clinically relevant variability of pressure estimates.

Inclusion Criteria

• Healthy asymptomatic dogs with a  TR murmur
• Dogs with mild to moderate pulmonary hypertension based on TR
• Dogs with severe pulmonary hypertension based on TR

Study Design

A baseline echocardiographic study will be done to identify suitable dogs. Dogs then will complete the 6-minute exercise test (an easy leash walk for 6 minutes). An echocardiogram will be performed before and after  6 minutes of exercise, and after sedation. The sedation protocol is consistent with the standard of care for cardiology patients undergoing echocardiography.

Client Compensation

• Sedation and the echocardiography are to be covered by the study
• Clients will receive $200 towards their bill if enrolled

Client Cost

• Owners cover all regular costs (regular exam fee and charges for a comprehensive echocardiographic study).

Contact

Dr. K Schober (614-292-3551, ext. 4-8676)