Comparing measurements in dogs with Pulmonary Hypertension

Purpose

This study aims to compare the accuracy of measurements in the lungs obtained from a non-invasive heart ultrasound (echocardiogram) to the measurements obtained from right heart catheterization to better diagnose, classify, and treat pulmonary hypertension in dogs.

Background

Pulmonary hypertension is increased blood pressure within the vasculature (arteries, capillaries, and/or veins) of the lungs.  Many different diseases can result in an increase in pulmonary blood pressure, and appropriate treatment of pulmonary hypertension depends on the underlying disease causing it.  Because treatment depends on identifying the specific cause—whether it originates in the pulmonary arteries or is a secondary effect of heart disease—veterinarians need improved tools to diagnose and classify pulmonary hypertension. A catheter guided through the right side of the heart and into the pulmonary arteries is the most accurate "gold standard" method of measuring and diagnosing pulmonary hypertension. However, despite the low complication rate, right heart catheterization is considered invasive and involves more logistical and financial challenges.  Instead, most veterinarians rely on echocardiograms to look for evidence of pulmonary hypertension and estimate pressure measurements. Unfortunately, echocardiographic estimates can be imperfect and have not been investigated enough in a general population of dogs with pulmonary hypertension.  Better echocardiographic tools—especially if validated by right heart catheterization—would allow for improved diagnosis and classification of pulmonary hypertension, ultimately allowing for better treatment of pulmonary hypertension and expectations for owners.  

Exclusion Criteria

1. Concurrent major illnesses compromising patient stability
2. Presence of congenital heart defects
3. Presence of heartworm infection

Study Design

This study involves a single, one-time procedure with no necessary follow-up visits for the project. Dogs with measurable tricuspid regurgitation and a moderate or high suspicion of pulmonary hypertension based on an initial echocardiogram will be eligible for the study and placed into one of three groups based on their initial medical findings: suspected precapillary pulmonary hypertension, suspected postcapillary pulmonary hypertension, and suspected combined pre- and postcapillary pulmonary hypertension. They will be scheduled for a visit that will include a physical exam, sedation, right heart catheterization, and a second transthoracic echocardiogram.  The right side of the dog's neck will be shaved as a part of this study.

Compensation

The initial echocardiogram that identified the dog as an eligible participant, the physical exam, sedation, antibiotics, the right heart catheterization, the second echocardiogram, and bandage materials after the procedure will all be covered by participation in this study. The cost of preexisting or newly recommended medications, as well as recommended follow-up appointments, if necessary, will not be covered by participation in this study. If a previously performed echocardiogram has identified a dog as eligible, it will not be retroactively compensated. 

Funded by