Long-term survival of 23 dogs with pericardial effusions

Retrospective evaluation of clinical signs, clinical course, and prognosis between dogs with left atrial rupture secondary to myxomatous mitral valve disease and those with neoplastic cardiac tamponade (2015-2019): 70 cases

OBJECTIVE

To describe the clinical signs, clinical course, and prognosis of suspected left atrial rupture (LAR) secondary to myxomatous mitral valve disease (MMVD) in dogs and to compare them with dogs with suspected neoplastic cardiac tamponade (NCT).

DESIGN

Retrospective study from November 2015 to October 2019 SETTING: An out-of-hours Emergency Animal Hospital.

ANIMALS

Twenty-three dogs with LAR secondary to MMVD (LAR group) and 47 dogs with NCT (NCT group).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The following were the characteristics of the study population (LAR group vs NCT groups) with P < 0.05 as the significance threshold: male sex, 83% vs 66%; median age, 11.9 vs 12.5 years; and median weight, 3.8 vs 6.4 kg (P < 0.001). Chihuahuas and Miniature Dachshunds were overrepresented in the LAR and NCT groups, respectively. Statistically different clinical findings between the 2 groups were as follows (LAR vs NCT): pulmonary edema, 43% vs 0%; pericardial thrombus, 70% vs 6% (P < 0.001); ineffectiveness of pericardiocentesis (whether aspiration of pericardial fluid was successful or not), 58% vs 2% (P < 0.001); mortality rate within 48 hours of visiting hospital, 35% vs 9% (P < 0.01). No significant difference was observed in survival time after discharge between the 2 groups.

CONCLUSIONS

The proportion of dogs with a diagnosis of LAR secondary to MMVD in dogs with cardiac tamponade was higher than the previously reported rate. Furthermore, the frequency of pulmonary edema, ineffectiveness of pericardiocentesis, and short-term mortality rate was higher in the LAR group than in the NCT group.

The development of ventricular fibrillation as a complication of pericardiectomy in 16 dogs

OBJECTIVE

To describe the clinical characteristics, perioperative protocols, and outcomes in dogs diagnosed with ventricular fibrillation (VF) while undergoing pericardiectomy.

STUDY DESIGN

Retrospective, multi-institutional study.

ANIMALS

Sixteen client-owned dogs.

METHODS

Cases were accrued through a listserve request posted to 3 subspecialty veterinary societies. Dogs were included if they developed VF during a pericardiectomy performed through an open or thoracoscopic approach. Data collected included signalment, history and physical examination, surgical approach, histopathology, treatment, and outcome.

RESULTS

Indications for pericardiectomy included idiopathic chylothorax (n = 7), neoplasia (4), idiopathic pericardial effusion (4), and foreign body granuloma (1). Surgical approaches included thoracoscopy (12), intercostal thoracotomy (3) and median sternotomy (1). Electrosurgical devices were used to complete at least part of the pericardiectomy in 15 of 16 dogs. Ventricular fibrillation appeared to be initiated during electrosurgical use in 8/15 dogs. However, in 5/15 dogs it was not obviously associated with electrosurgical use. In 3/16 dogs the timing of initiation of VF was unclear. In 7/16 dogs, cardiac arrhythmias were noted prior to the development of VF. Fourteen of 16 dogs died from intraoperative VF.

CONCLUSION

In most dogs ventricular fibrillation was a fatal complication of pericardiectomy. Ventricular fibrillation might be associated with the use of electrosurgical devices and cardiac manipulation during pericardiectomy although a causal link could not be established from the data in this study.

CLINICAL SIGNIFICANCE

Surgeons must be aware of the risk of VF during pericardial surgery. Electrosurgery might need to be used judiciously during pericardiectomy, particularly in dogs exhibiting cardiac arrythmias.

Systematic review of the treatment options for pericardial effusions in dogs

OBJECTIVE

To evaluate the evidence for the conservative and surgical management of pericardial effusions for neoplastic and idiopathic etiologies in dogs.

STUDY DESIGN

Systematic review.

SAMPLE POPULATION

Peer-reviewed English-language articles describing the treatment and outcome of naturally occurring pericardial effusion in domestic dogs.

METHODS

A literature search was performed with PubMed, Cab Abstracts, Scopus, and Agricola in August 2019 for articles describing pericardial effusion treatment in dogs. Inclusion criteria were applied, and articles were evaluated for reported outcome and level of evidence by using The Oxford 2011 Levels of Evidence, a previously described hierarchical system, and GRADE (Grading of Recommendations, Assessment, Development and Evaluation).

RESULTS

One hundred eight of the 641 unique articles that were identified and evaluated met inclusion criteria. Most articles included were case studies (68.2%) or retrospective case series (25.2%), with all articles providing a low level of evidence. The articles had inconsistent inclusion criteria, outcome measures, and follow-up, making comparison of outcomes difficult.

CONCLUSION

Because of the low quality of evidence of the studies included in this systematic review and the variability of the outcomes, there is not sufficient evidence to recommend one treatment option rather than another.

CLINICAL SIGNIFICANCE

There is a requirement for higher quality evidence such as randomized controlled trials and prospective comparative cohort studies. Standardization of outcome measures reported for each treatment option and disease process studied will allow for better comparison of outcomes between studies.

Pericardioscopic imaging findings in cadaveric dogs: comparison of an apical pericardial window and sub-phrenic pericardectomy

OBJECTIVE

To compare the pericardioscopic cardiovascular anatomy visible between apical pericardial window (PW) and sub-phrenic pericardectomy (SPP).

STUDY DESIGN

Experimental study.

ANIMALS

Canine cadavers (n = 5).

METHODS

Thoracoscopy was performed using a transdiaphragmatic subxyphoid and right and left intercostal portals. A 4 cm × 4 cm apical PW was created with endoscopic scissors. The intra-pericardiac structures were then pericardioscopically assessed using a subjective ordinal scale (0: not visible, 1: <50% seen, 2: >50% seen) before SPP. Assessment was repeated after SPP.

RESULTS

An apical PW provided limited access to the cardiac structures, with only the right ventricle >50% visible in all cadavers. The right atrium, right auricle, left ventricle, right coronary artery, and interventricular paraconal branch of the left coronary artery were observed but were typically <50% visible after apical PW. The left atrium and auricle, and heart base could not be consistently seen through an apical PW. Sub-phrenic pericardectomy significantly improved observation of all intrapericardiac structures assessed, except for the right atrium and right ventricle.

CONCLUSIONS

PW centered over the cardiac apex limits evaluation of the pericardial space during pericardioscopy compared to SPP in cadaveric dogs.

Cardiac magnetic resonance in the differentiation of neoplastic and nonneoplastic pericardial effusion

BACKGROUND

Cardiac magnetic resonance (CMR) is the imaging modality of choice for cardiac tumors in people. Although neoplastic pericardial effusion (PE) carries a poor prognosis, benign idiopathic pericardial effusion does not. Definitive diagnosis is critical for surgical intervention, but currently available diagnostic techniques such as echocardiography and pericardial fluid cytology often are inconclusive.

HYPOTHESIS/OBJECTIVE

Describe CMR findings associated with PE and determine whether CMR aids in differentiation of benign and neoplastic causes of PE.

ANIMALS

Eight client-owned dogs with PE diagnosed by transthoracic echocardiography (TTE).

METHODS

CMR was performed with a 1.5 T, including dark blood, steady-state free procession cine, pre- and postcontrast T1-weighted imaging, and delayed inversion recovery prepped imaging.

RESULTS

CMR confirmed a cardiac mass and supported suspected tumor type in 4 dogs with suspected hemangiosarcoma. In 1 equivocal TTE case, CMR did not demonstrate a mass, but neoplasia was later diagnosed. In another equivocal case, CMR did not demonstrate a mass but showed findings consistent with a pericardiocentesis complication. In 1 dog without evidence of cardiac neoplasia, abdominal magnetic resonance imaging identified presumptive hepatic and splenic metastases. On reevaluation of the original CMR study, the 2 equivocal cases that were interpreted as tumor negative were reassessed as tumor positive.

CONCLUSIONS AND CLINICAL IMPORTANCE

CMR did not substantially improve diagnosis of cardiac tumors compared with TTE in these 8 cases, but it yielded useful descriptive information regarding extent, anatomic location, and potential tumor type and confirmed that CMR requires extensive additional training for tumor identification.

Metastatic Pericardial Tumors in a Dog With Equivocal Pericardial Cytological Findings

A metastatic tumor associated with pericardial effusion was diagnosed in a 6-year-old, female, mixed-breed dog. Echocardiography identified multiple echogenic masses adherent to both visceral and parietal pericardium, while results of pericardial fluid cytology were non-diagnostic. The distribution pattern of the masses is remarkable in that they protruded from both pericardial surfaces, rather than one, and demonstrated an oscillatory motion during the cardiac cycle. Pathological examination confirmed the diagnosis of multiple metastatic tumors of the pericardium, with the primary tumor being an anaplastic gastric adenocarcinoma.