Pacemaker-lead-associated thrombosis in dogs: a multicenter retrospective study.

INTRODUCTION: Pacemaker implantation is the treatment of choice for clinically relevant bradyarrhythmias. Pacemaker-lead-associated thrombosis (PLAT) occurs in 23.0-45.0% of people with permanent transvenous pacemakers. Serious thromboembolic complications are reported in 0.6-3.5%. The incidence of PLAT in dogs is unknown. ANIMALS, MATERIALS AND METHODS: multicenter retrospective study of seven centers with 606 client-owned dogs undergoing permanent pacemaker implantation between 2012 and 2019. 260 dogs with a transvenous pacemaker with echocardiographic follow-up, 268 dogs with a transvenous pacemaker without echocardiographic follow-up and 78 dogs with an epicardial pacemaker. RESULTS: 10.4% (27/260) of dogs with transvenous pacemakers and echocardiographic follow-up had PLAT identified. The median time to diagnosis was 175 days (6-1853 days). Pacemaker-lead-associated thrombosis was an incidental finding in 15/27 (55.6%) dogs. Of dogs with a urine protein:creatinine ratio measured at pacemaker implantation, dogs with PLAT were more likely to have proteinuria at pacemaker implantation vs. dogs without PLAT (6/6 (100.0%) vs. 21/52 (40.4%), P=0.007). Urine protein:creatinine ratio was measured in 12/27 (44.4%) dogs at PLAT diagnosis, with proteinuria identified in 10/12 (83.3%) dogs. Anti-thrombotic drugs were used following the identification of PLAT in 22/27 (81.5%) dogs. The thrombus resolved in 9/15 (60.0%) dogs in which follow-up echocardiography was performed. Dogs with PLAT had shorter survival times from implantation compared to those without PLAT (677 days [9-1988 days] vs. 1105 days [1-2661 days], P=0.003). CONCLUSIONS: Pacemaker-lead-associated thrombosis is identified in 10.4% (27/260) of dogs following transvenous pacing, is associated with proteinuria, can cause significant morbidity, and is associated with reduced survival times.

Transvenous correction of patent ductus arteriosus in two toy-breed dogs with the Amplatzer™ Vascular Plug 4.

Two Pomeranian dogs referred for interventional correction of a left-to-right shunting patent ductus arteriosus (PDA) had inadequate femoral arterial access for any occlusion device other than micro coils. The decision was made to attempt correction of the PDA using the Amplatzer™ Vascular Plug 4 (AVP4) from a femoral venous approach. An AVP4 was successfully deployed in each dog with complete occlusion noted within 5 min. Complete occlusion was persistent at 24 h after the procedure, while both dogs were subclinical, had no residual ductal flow, and complete or near complete reverse cardiac remodeling at subsequent visits. This report demonstrates the feasibility of PDA occlusion with the AVP4 from the femoral venous approach in small dogs where femoral arterial access is inadequate for other occlusion devices.

The pharmacokinetics and analgesic effects of extended-release buprenorphine administered subcutaneously in healthy dogs.

Buprenorphine is a partial µ agonist opioid used for analgesia in dogs. An extended-release formulation (ER-buprenorphine) has been shown to provide effective analgesia for 72 hr in rats and mice. Six healthy mongrel dogs were enrolled in a randomized, blinded crossover design to describe and compare the pharmacokinetics and pharmacodynamics of ER-buprenorphine administered subcutaneous at 0.2 mg/kg (ER-B) and commercially available buprenorphine for injection intravenously at 0.02 mg/kg (IV-B). After drug administration, serial blood samples were collected to measure plasma buprenorphine concentrations using liquid chromatography/mass spectrometry detection. Heart rate, respiratory rate, body temperature, sedation score, and thermal threshold latency were recorded throughout the study. Median (range) terminal half-life, time to maximum concentration, and maximum plasma concentration of ER-buprenorphine were 12.74 hr (10.43-18.84 hr), 8 hr (4-36 hr), and 5.00 ng/ml (4.29-10.98 ng/ml), respectively. Mild bradycardia, hypothermia, and inappetence were noted in both groups. Thermal threshold latency was significantly prolonged compared to baseline up to 12 hr and up to 72 hr in IV-B and ER-B, respectively. These results showed that ER-buprenorphine administered at a dose of 0.2 mg/kg resulted in prolonged and sustained plasma concentrations and antinociceptive effects up to 72 hr after drug administration.