Right ventricular systolic and diastolic function assessed by two-dimensional speckle tracking echocardiography in dogs with myxomatous mitral valve disease

Two-dimensional echocardiographic right heart ratios for assessment of right heart size in dogs: Reference intervals and reproducibility

BACKGROUND

Reference intervals for simple body weight-independent measurements of right heart size and function are limited.

OBJECTIVES

Generate reference intervals for measurements of right heart size indexed to the long-axis aortic valve diameter (AoD) or corresponding left heart structure (right heart ratios) and describe the reproducibility of these indices.

ANIMALS

Ninety healthy adult dogs of variable body weight.

METHODS

Prospective study. All dogs underwent an echocardiogram performed by the same operator. Numerous linear 2-dimensional measurements of right heart size and function from different imaging planes were performed. Eight dogs underwent repeated echocardiograms by the same operator on 3 different days, and 3 different operators performed repeated echocardiograms on the same day. Reference intervals were generated using the Clinical Laboratory Standards Institute method. Reproducibility was quantitated using coefficients of variation (CVs) and reproducibility coefficients.

RESULTS

Reference intervals for right heart ratios were generated and allow simple assessments of right heart size and function that do not require a scaling exponent or body weight table. Right heart ratios did not show clinically relevant associations with body weight. All CVs were <22.6%. In general, CVs for right heart measurements indexed to AoD were lower compared with right heart measurements indexed to the corresponding left heart structure.

CONCLUSIONS AND CLINICAL IMPORTANCE

Reference intervals for simple body weight-independent right heart ratios are available to help detect abnormalities of right heart size and function. Reproducibility coefficients might be useful to help identify meaningful changes in right heart size during serial evaluations.

Pulmonary thrombotic pulmonary hypertension managed using antithrombotic and pulmonary vasodilator treatment

An 8-year-old Leonberger receiving immunosuppressive treatment with clinical signs of acute dyspnea, cyanosis, and difficulty standing was referred to our institution (Day 1). Treatment including oxygen, clopidogrel, and low-molecular-weight heparin was initiated for suspected pulmonary thrombosis. However, exertional dyspnea persisted until Day 10, and increased tricuspid regurgitation velocity, pulmonary vascular resistance, and McConnell's signs also were observed. Thus, beraprost sodium was administered PO on Day 11 to treat suspected pulmonary hypertension. On Day 13, contrast-enhanced computed tomography identified extensive contrast defects in the pulmonary arteries, and IV monteplase was administered on Days 14 and 18, with marked improvement in respiratory status and exertional dyspnea on Day 20. Right ventricular function and McConnell signs also improved, and tricuspid regurgitation velocity and pulmonary vascular resistance decreased. On Day 250, echocardiography indicated further improvement in pulmonary hypertension pathophysiology. The patient was still progressing well with antithrombotic and pulmonary vasodilator treatment 400 days later.

Echocardiographic characteristics of dogs with pulmonary hypertension secondary to respiratory diseases

BACKGROUND

Pulmonary hypertension (PH) secondary to respiratory disease is caused by pulmonary vascular remodeling and hypoxia. Severe PH can induce various clinical signs, including syncope and right-sided heart failure.

HYPOTHESIS/OBJECTIVES

To investigate the echocardiographic characteristics in dogs with PH secondary to respiratory diseases.

ANIMALS

Thirty-one dogs with respiratory diseases with or without PH and 15 healthy dogs.

METHODS

Prospective cross-sectional study. Dogs were classified according to respiratory disease (obstructive airway/lung disease [OALD] or restrictive lung disease [RLD]) and PH-relevant signs. The association between echocardiographic variables and PH (classified by respiratory disease and PH-relevant signs) was investigated.

RESULTS

Twenty-one dogs were diagnosed with PH; of these, 11 showed PH-related signs (OALD, n = 2; RLD, n = 9), 14 had right ventricular hypertrophy, and 19 had pulmonary arterial enlargement. Right ventricular dysfunction and dilatation were observed only in dogs with PH-related signs (n = 10). Left and right ventricular stroke volumes were significantly lower in dogs with PH (median [interquartile range]: 17.2 [12.4-20.8] and 16.8 [15.3-29.5] mL/m2 , respectively). Dogs with RLD had higher echocardiography-estimated pulmonary vascular resistance than those with OALD (median [interquartile range]: 3.1 [1.9-3.3] and 1.6 [1.3-2.2], respectively).

CONCLUSIONS AND CLINICAL IMPORTANCE

Pulmonary arterial enlargement was the most common echocardiographic finding in dogs with PH secondary to respiratory diseases. Right ventricular dysfunction, dilatation, and decreased left and right ventricular stroke volume were significantly associated with the PH-related signs, indicating that comprehensive echocardiography is recommended in dogs with respiratory disease. Restricted lung disease might induce more severe PH than OALD.

Cardiovascular Effect of Epoprostenol and Intravenous Cardiac Drugs for Acute Heart Failure on Canine Pulmonary Hypertension

Pulmonary hypertension (PH) is a life-threatening complication in dogs with cardiopulmonary disease. Epoprostenol is an intravenous pulmonary vasodilator used to treat PH in humans; however, its efficacy in dogs remains unknown. We investigated the cardiovascular effects of epoprostenol and several cardiac agents for acute heart failure in canine models of chronic PH. Six dogs with chronic PH were anesthetized and underwent right heart catheterization and echocardiography before and after infusion of epoprostenol, dobutamine, dopamine and pimobendane. (The drug administration order was the same for all dogs). High-dose epoprostenol (15-20 ng/kg/min) tended to decrease pulmonary arterial pressure (PAP) while significantly decreasing pulmonary and systemic vascular resistance and increasing left and right ventricular (LV and RV, respectively) function. Pimobendan significantly increased LV and RV functions without increasing PAP. Conversely, dobutamine and dopamine significantly increased LV and RV function as well as PAP. This study revealed the efficacy of epoprostenol in treating canine PH through its pulmonary and systemic vasodilating effects. Although catecholamines improve LV and RV function, they might worsen PH pathophysiology, and careful monitoring may be necessary when using these drugs. Pimobendan improved LV and RV function without increasing PAP; however, a stronger vasodilating effect was observed with epoprostenol.

A Case of a Small-Breed Dog with Diet-Related Dilated Cardiomyopathy Showing Marked Improvements in Cardiac Morphology and Function after Dietary Modification

An 11-year-old intact female Papillion weighing 2.1 kg was referred to our institution with the main complaint of shallow, rapid breathing. At the first visit (day 0), although clinical signs improved due to the use of medication from the primary hospital, transthoracic radiography and echocardiography revealed left heart enlargement and left ventricular dysfunction. A clinical diagnosis of dilated cardiomyopathy (DCM) was made and oral administration of pimobendan, temocapril, and taurine was initiated. However, on day 10, the respiratory status worsened and furosemide was prescribed. On day 54, no significant improvement in heart size was observed. Additionally, the diet that this patient received met the recommendation for diet-related DCM by the U.S. Food and Drug Administration, and the patient’s diet was changed from a grain-free diet to a grain-containing diet. On day 1191, the patient’s respiratory status was stable and no clinical signs were observed. Transthoracic radiography and echocardiography revealed an improvement in left heart size. Additionally, improvements in the left and right ventricular myocardial strains were observed after changing the diet. We suggest that it may be necessary to suspect a dietary association with dilated cardiomyopathy, and a good prognosis might be expected by dietary modification, even in small-breed dogs.

Beraprost Sodium for Pulmonary Hypertension in Dogs: Effect on Hemodynamics and Cardiac Function

Simple Summary

Pulmonary hypertension is a potentially life-threatening disease among dogs that is characterized by increased pulmonary arterial pressure and pulmonary vascular resistance. In veterinary medicine, a phosphodiesterase-5 inhibitor such as sildenafil is the most common drug used to treat pulmonary hypertension. However, the availability of sildenafil is limited because of its high cost, difficulty in obtaining the drug in some areas, and potential inter-individual variability in the response to sildenafil therapy. Beraprost sodium is one of the most common drugs used to treat pulmonary hypertension in humans. However, little is known about its efficacy in dogs with pulmonary hypertension. In this study, beraprost sodium showed significant pulmonary and systemic vasodilation without any adverse effects in sixteen dogs with pulmonary hypertension. Additionally, echocardiographic improvements in cardiac function and pulmonary and systemic circulation were observed. These results emphasize the potential efficacy of beraprost sodium in treating canine pulmonary hypertension.

Abstract

Pulmonary hypertension (PH) is a fatal condition that affects many dogs. In humans, PH is often treated with beraprost sodium (BPS). However, the effectiveness of BPS for canine PH has not been established. This study aimed to evaluate the clinical and cardiovascular response of BPS in canine patients with PH of various causes. Sixteen dogs with PH (post-capillary PH, n = 8; pre-capillary PH, n = 8) were included. BPS was continuously administered twice daily at 15 µg/kg. All dogs underwent echocardiography, including speckle-tracking analysis and blood pressure measurement, before and after BPS administration. Continuous BPS administration (range: 13.2–22.0 µg/kg) significantly decreased the pulmonary and systemic vascular impedance and increased left and right ventricular myocardial strain. In dogs with post-capillary PH, BPS administration caused no significant worsening of the left atrial pressure indicators. No side effects of BPS were observed in any dog. BPS also improved cardiac function and pulmonary circulation through pulmonary vasodilation, suggesting that BPS may be an additional treatment option for canine PH of various causes. Particularly, BPS increased left ventricular function and systemic circulation without worsening the left heart loading condition in dogs with post-capillary PH.

Effect Evaluation of Echocardiography on Right Ventricular Function in Patients after the Recovering from Coronavirus Disease 2019

This research was aimed at exploring the changes in right ventricular function in patients after the recovery of coronavirus disease 2019 (COVID-19) under echocardiography and providing a reference for the rehabilitation and treatment of COVID-19 patients. Three echocardiographic follow-up examinations were performed on 40 recovered COVID-19 patients and 40 healthy people. Right ventricular function between patients after COVID-19 rehabilitation and healthy people was compared. The mean values of right ventricular fractional area change (RVFAC), tricuspid annular plane systolic excursion (TAPSE), right ventricular ejection fraction (RVEF), right myocardial performance index (RMPI), and tricuspid annular plane systolic speed (S') were compared between patients after COVID-19 rehabilitation and healthy subjects. The technical parameters of two-dimensional speckle tracking were compared. The results showed that the differences in RVFAC, TAPSE, RVEF, and RMPI between COVID-19 patients and healthy controls were not significant during the three follow-up periods (P > 0.05). At the first follow-up, the S' was 12.78 cm/s in COVID-19 patients and 13.18 cm/s in healthy subjects. At the second follow-up, the S' was 11.98 cm/s in COVID-19 patients and 12.77 cm/s in healthy subjects. At the third follow-up, the S' was 12.79 cm/s in COVID-19 patients and 13.12 cm/s in healthy subjects. There was no significant difference between the two groups (P > 0.05). In addition, there was no significant difference in right ventricular function between COVID-19 patients and healthy controls, and there was no significant difference in cardiovascular symptoms (P > 0.05). In summary, COVID-19 had no substantial effect on right ventricular function and better recovery in patients.

Investigation of Beraprost Sodium on Cardiac Function and Hemodynamics in Canine Models of Chronic Pulmonary Hypertension

Pulmonary hypertension (PH) is a life-threatening disease in dogs characterized by increased pulmonary arterial pressure (PAP) and/or pulmonary vascular resistance. No study has evaluated the utility of Beraprost sodium (BPS) in dogs with PH. This study aimed to evaluate the effect of BPS on cardiac function and hemodynamics and examine the optimal dose of BPS in canine models of chronic embolic PH. In this prospective crossover study, three doses of BPS (5, 15, and 25 μg/kg, twice a day) were examined in eight canine models of chronic embolic PH. All model dogs underwent invasive PAP measurement, echocardiography, and non-invasive systemic blood pressure measurement before and after continuous administration of oral BPS for 1 week. No side effects of BPS were observed in any dog during the study. All doses of BPS significantly decreased systolic PAP and pulmonary vascular impedance. Additionally, systemic vascular impedance significantly decreased with 15 and 25 μg/kg of BPS. The right ventricular stroke volume and longitudinal strain significantly decreased with all doses of BPS. The left ventricular stroke volume and circumferential strain decreased with 15 μg/kg BPS. BPS was well-tolerated in this study. A dose-dependent vasodilating effect on pulmonary vessels was observed in canine models of chronic PH. Additionally, 15 μg/kg BPS showed a balanced vasodilating effect on systemic and pulmonary vessels. Furthermore, with a decrease in systemic and pulmonary vascular impedance, the left and right ventricular functions were significantly improved. Our results suggest that BPS may be useful in the treatment of canine PH.

Utility of Real-Time Three-Dimensional Echocardiography for the Assessment of Right Ventricular Morphology and Function in Large Animal Models

Real-time three-dimensional echocardiography (RT3DE) enables a noninvasive assessment of right ventricular (RV) morphology. However, no study has evaluated the relationship between RV function obtained by RT3DE and RV pressure-volume loops. This hypothesis-driven, experimental study aimed to assess the utility of RT3DE in the evaluation of RV morphology and function. Ten anesthetized beagle dogs sequentially underwent dobutamine infusion, acute infusion of lactated Ringer’s solution, and furosemide administration to alter RV contractility and loading conditions. RV pressure-volume loop-derived hemodynamic measurements and echocardiography, including two-dimensional speckle-tracking echocardiography and RT3DE, were performed in each study protocol. Bland−Altman analysis showed strong agreement in RV volume, ejection fraction, and stroke volume obtained by right heart catheterization and RT3DE. Multiple regression analyses revealed that the peak myocardial velocity of the lateral tricuspid annulus (RV s’) and global RV longitudinal strain rate were significantly associated with end-systolic elastance (adjusted r2 = 0.66, p < 0.001). RV s’, RV free wall longitudinal strain, and RT3DE-derived stroke volume/end-systolic RV volume ratio were associated with RV pressure-volume loops-derived end-systolic/arterial elastance ratio (adjusted r2 = 0.34, p < 0.001). RT3DE could detect the changes in catheterization-derived RV volume with a strong agreement and might be useful in estimating RV-pulmonary arterial coupling.