PRESERVED RIGHT VENTRICULAR INTEGRITY IN A NEW TELEMETRIC RAT MODEL OF SEVERE PULMONARY HYPERTENSION

Telemetric monitoring of hemodynamic parameters has become an established standard in experimental models of pulmonary arterial hypertension (PAH). To that purpose, a dedicated catheter is usually implanted through the right ventricular wall of study animals. Drawbacks of this standard technique are: obtained pressures are from the right ventricle and therefore only surrogates for pulmonary arterial pressures, and furthermore, right ventricular myocardium is always damaged to a certain degree. To overcome shortcomings of standard hemodynamic assessment, we modified an established rat model, where severe PAH is induced by left-sided pneumonectomy plus monocrotaline injection. We describe here a novel telemetry catheter implantation technique, where the device is advanced into the pulmonary artery via the remaining stump, and the transmitter is placed in a subcutaneous pocket. A total of 105 rats were operated with a median implantation time of 50 (30-88)min and an excellent perioperative survival of 93%. After monocrotaline induction on day 7, animals developed severe PAH with mean pressures of 75.9 ±18.6 mmHg (systolic), 55.0 ±18.0 mmHg (mean) and 42.1 ±21.3 mmHg (diastolic) after four weeks. Post-mortem, the animals showed severe right ventricular hypertrophy and histological analysis confirmed excessive medial hypertrophy and intimal hyperplasia, both characteristic features of human PAH. Comparison of the new telemetric model with standard microtip catheterization did not show relevant measurement differences. We established the first experimental animal model for PAH with preserved right ventricular integrity that allows direct telemetric monitoring of real-time systolic, mean and diastolic pressures in the main pulmonary artery of freely moving rats.

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