# Echocardiographic Evaluation of Indices of Severity of Pulmonary Stenosis in Dogs: Reproducibility and Effects of General Anesthesia

## TL;DR

This study examines how general anesthesia affects measurements of pulmonary stenosis severity in dogs and evaluates the consistency of these measurements.

## Contribution

The study identifies the impact of general anesthesia on flow-dependent and flow-independent indices of pulmonary stenosis severity in dogs.

## Key findings

- General anesthesia reduces mean and maximum pressure gradients in dogs with pulmonary stenosis.
- Flow-independent indices like velocity ratio remain unchanged under general anesthesia.
- Reproducibility of severity indices varies, with the lowest variation observed for velocity ratio.

## Abstract

The effects of general anesthesia (GA) on less flow‐dependent (velocity ratio, velocity time integral [VTI] ratio and indexed pulmonary valve area [iPVA]) and flow‐dependent (mean [PVmeanPG] and maximum pressure gradient [PVmaxPG]) indices of severity of pulmonary stenosis (PS) are unclear.

Determine the effects of GA on indices of severity of PS in dogs undergoing an interventional procedure (IP). Determine the reproducibility of indices of severity of PS.

Thirty‐nine dogs with PS.

Prospective cross‐sectional study. Five repeated echocardiograms were performed over 3 days. Day 1: two echocardiograms were performed by 2 different operators. Day 2: echocardiograms were performed before and after GA but before IP. Day 3: an echocardiogram was performed after the IP.

After GA, median (IQR) cardiac index (2.1 [1.6–2.6] L/min/m2), PVmeanPG (45.0 [26.0–55.2] mmHg), PVmaxPG (76.6 [46.6–100.3] mmHg) were decreased (p
≤0.001) compared to before GA (2.8 [2.2–3.0] L/min/m2, 55.9 [47.6–73.1] mmHg, 96.1 [81.6–127.0] mmHg, respectively). There were no differences (p
≥0.35) in velocity ratio, VTI ratio, or iPVA after GA. Intra‐operator and inter‐operator coefficients of variation (95% CI) were highest for iPVA (13.8% [10.4–18.4] and 13.5% [11.0–18.4], respectively) and lowest for velocity ratio (9.2% [7.7–12.3] and 9.3% [7.7–12.4], respectively).

PVmeanPG and PVmaxPG might be misleading in states of reduced flow. An integrative assessment of severity of PS that includes less flow‐dependent indices is recommended. Reproducibility of indices of severity of PS should be considered when re‐evaluating dogs with PS.