# Comparative Echocardiographic Evaluation of Right Pulmonary Artery Dimensions and Right Pulmonary Artery Distensibility Index in Dogs with Heartworm Disease

## TL;DR

This study compares two methods for measuring pulmonary artery distensibility in dogs with heartworm disease to determine their accuracy in diagnosing pulmonary hypertension.

## Contribution

The study evaluates the agreement and diagnostic accuracy of two RPADi methods in dogs with heartworm disease.

## Key findings

- RPADVisser and RPADVenco showed high similarity but 5.6% of cases had differing PH diagnoses.
- Significant differences were found in RPAD measurements across healthy, infected without PH, and infected with PH groups.
- The study highlights the need for standardized methods for echocardiographic PH assessment in heartworm disease.

## Abstract

The existence of two methods for obtaining the right pulmonary artery distensibility index (RPADi) has complicated the standardization and use of echocardiographic measurements in determining pulmonary hypertension (PH) in heartworm disease and other cardiorespiratory conditions. This study aimed to determine the accuracy and agreement between RPADVisser and RPADVenco in diagnosing PH and to assess the differences in pulmonary arterial diameters in dogs with heartworm. RPADVisser and RPADVenco were measured in 248 dogs, along with the values for RPADmax, RPADmin, RPADmax:Ao, and RPADmin:Ao for each method. The dogs were grouped into three categories: healthy, infected without PH, and infected with PH. Statistical analyses revealed significant differences between these groups for RPADmax, RPADmin, RPADmax:Ao, and RPADmin:Ao. Additionally, this study found high similarity and agreement between RPADVisser and RPADVenco. However, 5.6% of the cases showed differences in the diagnosis for PH, indicating that these methods cannot be used interchangeably.

The existence of several methods to obtain the right pulmonary artery distensibility index (RPADi) has complicated the standardization and use of echocardiographic measurement for the determination of pulmonary hypertension (PH) in heartworm disease and other cardiorespiratory pathologies. Therefore, the objective was to determine the precision and agreement between RPADVisser and RPADVenco in the diagnosis of PH and to evaluate the differences in pulmonary arterial diameters in dogs with heartworm. The RPADVisser and RPADVenco were determined in 248 dogs and the determinations of RPADmax, RPADmin, RPADmax:Ao, and RPADmim:Ao were also obtained from each of the methods. Through the presence/absence of heartworm disease and the presence of PH (RPADi < 30% in both methods), three groups were created: healthy animals, infected dogs without PH, and animals infected with PH. Statistical analyzes determined significant differences between the analyzed groups for RPADmax, RPADmin, RPADmax:Ao, and RPADmim:Ao. Likewise, a high similarity and agreement was reported between RPADVisser and RPADVenco; however, 5.6% of the cases showed a different diagnosis for the presence of PH in the animals analyzed, showing that these methods cannot be used interchangeably.