Case, J. Brad

Objective: We tested the feasibility and effectiveness of a percutaneous atrial transseptal extracorporeal membrane oxygenation (ECMO) cannulation strategy in a right ventricular failure (RVF) model. Methods: We performed 4 nonsurvival porcine experiments. Percutaneous transseptal access was achieved using a steerable introducer. For guidance, we used fluoroscopy, transesophageal echocardiogram (TEE), and intracardiac echocardiography (ICE). A ProtekDuo rapid deployment cannula (LivaNova, London, UK) was advanced across the septum into the left atrium by 2 to 3 cm. Pulmonary hypertension (PH) was induced by partially clamping the pulmonary artery. ECMO flow was cycled from high (2 to 3 L/min) to low (0.2 to 0.3 L/min) over 2 to 3 hours. Results: Transseptal access using TEE and fluoroscopy was successful in 1 animal and unsuccessful in 1 animal. ICE provided optimal visualization for the remaining 2 animals. Mean arterial pressure (MAP) was associated immediately and consistently with high versus low ECMO flow rate (mean difference: 29 ± 3.1 mm Hg, P = 0.004) but was not restored to baseline values. RV pressure values were dynamic. Given time to equilibrate, mean RV pressure was restored to a baseline level. Conclusions: Percutaneous right atrium to left atrium transseptal cannulation relieved PH-RVF. MAP was restored to a viable level, and mean RV pressure was restored to a baseline level. Transseptal ECMO shows promise as a cannulation strategy to bridge patients with PH-RVF to lung transplant.

AbstractObjectiveTo describe the embolization technique and short‐term clinical outcome in dogs undergoing lymphatic embolization (LE) as part of treatment for presumptive idiopathic chylothorax (IC). Additionally, to document findings in computed tomography lymphangiography (CTLa) following embolization.Study designProspective case series.AnimalsEight client‐owned dogs.MethodsDogs underwent CTLa followed by thoracic duct ligation (TDL), pericardiectomy (PC) and LE. A mixture of 3:1 lipiodol: n‐butyl cyanoacrylate embolic solution was injected through a catheterized mesenteric lymphatic vessel via limited abdominal approach using intraoperative fluoroscopy. CTLa was scheduled for 12 weeks postoperatively, and long‐term follow‐up was obtained via telephone contact.ResultsLE was technically successful in six of the eight dogs; and clinically successful in five of the six dogs. In the unsuccessful dog, a diagnosis of lymphangiosarcoma was determined, and the owners elected for euthanasia. Five dogs who underwent successful LE underwent CTLa at 12 weeks. Complete resolution of pleural effusion occurred in three dogs and scant pleural effusion in two dogs. A robust lymphatic embolus preventing antegrade continuation of radiocontrast was documented in all five dogs. Five of the six dogs that underwent LE, were alive and clinically normal at 358–960 days postoperatively.ConclusionsLE is a feasible part of treatment for dogs with IC. Additionally, a robust lymphatic embolus and lack of radiocontrast flow past the embolus was documented at 12 weeks following surgery.Clinical significanceLE has the potential to reduce surgical failure by reducing efferent lymphatic chyle flow, occluding missed lymphatic branches and preventing the development of collateral branches.

Abstract OBJECTIVE To determine the optimal energy profile for and to assess the feasibility and efficacy of ultrasonographic and laparoscopic guidance for microwave ablation (MWA) of clinically normal canine ovaries. SAMPLE 44 extirpated ovaries from 22 healthy dogs. PROCEDURES In the first of 2 trials, 13 dogs underwent oophorectomy by routine laparotomy. Extirpated ovaries underwent MWA at 45 W for 60 (n = 11) or 90 (12) seconds; 3 ovaries did not undergo MWA and served as histologic controls. Ovaries were histologically evaluated for cell viability. Ovaries without viable cells were categorized as completely ablated. Histologic results were used to identify the optimal MWA protocol for use in the subsequent trial. In the second trial, the ovaries of 9 dogs underwent MWA at 45 W for 90 seconds in situ. Ultrasonographic guidance for MWA was deemed unfeasible after evaluation of 1 ovary. The remaining 17 ovaries underwent MWA with laparoscopic guidance, after which routine laparoscopic oophorectomy was performed. Completeness of ablation was histologically assessed for all ovaries. RESULTS 2 ovaries were excluded from the trial 1 analysis because of equivocal cell viability. Six of 11 ovaries and 10 of 10 ovaries that underwent MWA for 60 and 90 seconds, respectively, were completely ablated. In trial 2, laparoscopic-guided MWA resulted in complete ablation for 12 of 17 ovaries. Dissection of the ovarian bursa for MWA probe placement facilitated complete ablation. CONCLUSIONS AND CLINICAL RELEVANCE Laparoscopic-guided MWA at 45 W for 90 seconds was feasible, safe, and effective for complete ablation of clinically normal ovaries in dogs.

AbstractObjectiveTo determine laparoscopic accessibility of liver lobes and access to the hilus and describe laparoscopic microwave ablation (LMWA) in 2 dogs with hepatic neoplasia.Study designExperimental/descriptive case series.Sample populationSix canine cadavers and 2 clinical dogs.MethodsCadavers in dorsal recumbency underwent laparoscopic assessment of the liver. A 17 gauge MWA probe was inserted to create an ablation zone at the most proximal aspect of the hilus. The distance from the center of each ablation zone to the most proximal aspect of the corresponding hilus was determined. Two dogs with hepatic neoplasia underwent LMWA.ResultsAll lobes of the canine liver were accessible via laparoscopy. The median (interquartile range) distances from the ablation zones to the hilus for the caudate process, left lateral, left middle, quadrate, right lateral, and right middle lobes were 2.2 (1.2–2.6), 2.1 (1–4.4), 1.5 (1.4–3.7), 2, 1, 2.5 (1–4.1) cm, respectively. Histopathologic diagnoses treated by LMWA included metastatic hemangiosarcoma and primary hepatocellular carcinoma. Laparoscopic microwave ablation was technically feasible, and no complications from the procedure resulted.ConclusionLaparoscopic access to the hilus of each liver lobe is possible via a ventrodorsal approach provided reverse Trendelenburg and lateral rotation is used, especially for the right lateral lobe. Laparoscopic microwave ablation is feasible in some dogs with hepatic neoplasia. The indications for and efficacy of LMWA for hepatic neoplasia in dogs requires additional investigation.Clinical significanceLaparoscopic access to all liver lobes and MWA of some neoplastic lesions is feasible in a canine pilot study.

AbstractObjectiveTo describe video‐assisted microwave ablation (VAMA) for the treatment of a metastatic lung lesion secondary to right forelimb osteosarcoma in a dog.Study designCase report.AnimalsA 10‐year‐old female spayed mixed breed dog with a metastatic lung lesion secondary to appendicular osteosarcoma.MethodsAn osteosarcoma of the right distal scapula and proximal humerus that was suspected to be a radiation‐induced osteosarcoma was treated with limb amputation and carboplatin chemotherapy. The patient developed pulmonary metastatic lesions and hypertrophic osteopathy (HO). VAMA of a metastatic lesion in the right caudal lung lobe was performed 227 days after amputation. The procedure was performed without complication.ResultsFollow‐up information with the referring veterinarian 40 days after VAMA indicated that the patient was stable and that the clinical signs of HO had resolved. Thoracic radiographs taken by the referring veterinarian (RDVM) at monthly intervals showed that the previously treated metastatic lesion was stable. At 134 days from VAMA, the patient presented to the RDVM for lethargy and dyspnea and was transferred to an emergency clinic. The patient arrested and died 136 days from the VAMA procedure while hospitalized. A postmortem was not performed.ConclusionVAMA for pulmonary metastatic lesions is technically feasible and allows for the treatment of symptoms associated with HO and minimally invasive management of pulmonary metastases in the case reported.