Surgical Placement of Catheters for Long-term Cardiovascular Exercise Testing in Swine

Abstract

This protocol describes the surgical procedure to chronically instrument swine and the procedure to exercise swine on a motor-driven treadmill. Early cardiopulmonary dysfunction is difficult to diagnose, particularly in animal models, as cardiopulmonary function is often measured invasively, requiring anesthesia. As many anesthetic agents are cardiodepressive, subtle changes in cardiovascular function may be masked. In contrast, chronic instrumentation allows for measurement of cardiopulmonary function in the awake state, so that measurements can be obtained under quiet resting conditions, without the effects of anesthesia and acute surgical trauma. Furthermore, when animals are properly trained, measurements can also be obtained during graded treadmill exercise.Flow probes are placed around the aorta or pulmonary artery for measurement of cardiac output and around the left anterior descending coronary artery for measurement of coronary blood flow. Fluid-filled catheters are implanted in the aorta, pulmonary artery, left atrium, left ventricle and right ventricle for pressure measurement and blood sampling. In addition, a 20 G catheter is positioned in the anterior interventricular vein to allow coronary venous blood sampling.After a week of recovery, swine are placed on a motor-driven treadmill, the catheters are connected to pressure and flow meters, and swine are subjected to a five-stage progressive exercise protocol, with each stage lasting 3 min. Hemodynamic signals are continuously recorded and blood samples are taken during the last 30 sec of each exercise stage.The major advantage of studying chronically instrumented animals is that it allows serial assessment of cardiopulmonary function, not only at rest but also during physical stress such as exercise. Moreover, cardiopulmonary function can be assessed repeatedly during disease development and during chronic treatment, thereby increasing statistical power and hence limiting the number of animals required for a study. Video LinkThe video component of this article can be found at

Transition from post‐capillary pulmonary hypertension to combined pre‐ and post‐capillary pulmonary hypertension in swine: a key role for endothelin

“…Four weeks after PVB or sham procedure, swine were anaesthetized and ventilated as described above and chronically instrumented as described previously (De Wijs‐Meijler et al . ). Briefly, under sterile conditions, the chest and pericardium were opened via the fourth left intercostal space and fluid‐filled polyvinylchloride catheters (Braun Medical Inc.) were inserted into the aortic arch, the pulmonary artery, the right ventricle and the left atrium for blood pressure measurement and blood sampling.…”

“…To test this hypothesis, we investigated the progression of PH using chronically instrumented swine (De Wijs‐Meijler et al . ), in a recently developed swine model of group II PH by pulmonary vein banding (PVB) (Garcia‐Alvarez et al . ; Aguero et al .…”

Validation of 4D flow CMR against simultaneous invasive hemodynamic measurements: a swine study

“…The swine were chronically catheterized for hemodynamic monitoring approximately 2 to 3 months prior to the scanning procedure. Surgical details have been extensively described previously [ 18 ]. In short, swine were sedated with an intramuscular injection of tiletamine/zolazepam (5 mg/kg), xylazine (2.25 mg/kg) and atropine (1 mg), intubated and ventilated with a mixture of O 2 and N 2 (1:2 v/v) to which 2% (v/v) isoflurane was added to maintain anesthesia.…”

Changes in the nitric oxide pathway of the pulmonary vasculature after exposure to hypoxia in swine model of neonatal pulmonary vascular disease

“…Hemodynamic parameters were continuously recorded and blood samples were collected during the last 45 sec of each exercise stage, at a time when hemodynamics had reached a steady state (De Wijs‐Meijler et al. ). After completing the exercise protocol, animals were allowed to rest on the treadmill.…”

“…The depth of anesthesia was checked regularly using a pain stimulus (toe-pinch). Due to premature death, caused by health problems related to exposure to hypoxia (N = 6), only 28 piglets (Normoxia, N = 16;, Hypoxia N = 12) were instrumented under sterile conditions as previously described (De Wijs-Meijler et al 2016). Briefly, the chest was opened via the fourth left intercostal space and fluid-filled polyvinylchloride catheters were inserted into the aortic arch, pulmonary artery, left atrium, and right ventricle for pressure measurements.…”