A Novel Right Ventricular Volume and Pressure Loaded Piglet Heart Model for the Study of Tricuspid Valve Function.

Summary

A novel recovery piglet heart model with combined pressure and volume overload on the right ventricle is described for the study of tricuspid valve function.

Abstract

Heart conditions in which the tricuspid valve (TV) faces either increased volume or pressure stressors are associated with premature valve failure. Mechanistic studies to improve our understanding of the underlying pathophysiology responsible for the development of premature TV failure are lacking. Due to the inability to conduct these studies in humans, an animal model is required. In this manuscript, we describe the protocols for a novel chronic recovery infant piglet heart model for the study of changes in the TV when placed under combined volume and pressure stress. In this model, volume loading of the right ventricle and the TV is achieved through the disruption of the pulmonary valve. Then pressure loading is accomplished through the placement of a pulmonary artery band. The success of this model is assessed at four weeks post intervention surgery through echocardiography, intracardiac pressure measurement, and pathologic examination of the heart specimens.

Introduction

The normal TV functions in a low volume and pressure stress environment. However, there are pediatric and adult heart conditions where the TV is either congenitally malformed or the cardiac physiology is such that the right ventricle and TV are challenged by increased volume (preload) and/or pressure (afterload) stress, such as Tetralogy of Fallot, Ebstein’s anomaly, congenitally corrected transposition of the great arteries, patients with transposition of the great arteries following an atrial switch procedure, idiopathic pulmonary hypertension and hypoplastic left heart syndrome. In these cardiac conditions, the TV is prone to premature valve failure, which in....

Protocol

The protocol and procedures in this manuscript were developed under the supervision of a veterinarian and performed in compliance with the guidelines of the Canadian Council on Animal Care and the guide for the care and use of laboratory animals. The protocol was approved by the institutional animal care committee at the University of Alberta. All individuals involved in the manuscript procedures received appropriate biosafety training.

1. Pre-procedure preparation, anesthesia and access

Discussion

During the development of this novel heart model, several considerations have impacted the final model design.

Piglet age and surgical exposure
Prior to formulation of the current piglet model, the team has worked on piglet cadavers ranging from one to six weeks of age with the goal to determine the age range where procedural instrumentation and exposure is adequate. As the surgical procedure required direct echocardiographic guidance, the piglet had to be of the appropr.......

Materials

Name	Company	Catalog Number	Comments
Drugs
1% lidocaine spray	WDDC	103365	Lidodan 30 mL
atropine sodium injection	WDDC/Rafter 8 Products		0.5 mg/mL
bupivacaine	WDDC/Sterimax		5 mg/mL
buprenorphine HCl slow release injection	Chiron Compounding Pharmacy		1 mg/mL
buprenorphine regular	WDDC/Champion Alstoe	121378	Vetergesic 0.3 mg/mL
cefazolin	WDDC/Fresenius Kabi	102016	1 g/vial
cephalexin capsule	WDDC/Novopharm		Novo-Lexin 250 mg/capsule
epinephrine	WDDC		Adrenalin (1:1000) 1 mg/mL
furosemide tablet	WDDC/Novopharm		10 mg tablet
Iodine Scrub/Spray	Cardinal Health	KF22422	Betadine brand
ketamine hydrochloride injection	WDDC/Vetoquinol	131771	Narketan 100 mg/mL
midazolam	WDDC/Sandoz	101100	5 mg/mL
norepinephrine	WDDC		1 mg/mL
pentobarbital sodium	WDDC/Bimeda-MTC	127189	Euthanyl 240 mg/mL
ranitidine injection	WDDC		25 mg/mL
ranitidine tablet	Sanis		300 mg tablet
Surgical Scrub Sponge	Stevens	333-377479	4% CHG Surgical Soap scrub brush
Equipment
24G peripehral IV catheter	BD		Insyte-N
5Fr double lumen central venous catheter	Arrow	CS-14502	20cm
5Fr single lumen umbilical vessel catheters	Covidien/Kendall	8888160333	Argyle 15 inches
6" Chest retractor	RRSMRI
6Fr triple lumen central venous catheter	Arrow	JR-42063-HPHNM	20cm
7Fr catheter sheath with flange	Dr. Coe custom designed
Adson forceps	RRSMRI
Aestiva/5 Ventilator	GE Datex Ohmeda
Atraumatic forceps	Teleflex	351865
bioptome	Dr. Coe lab		Mansfield Biopsy Forceps
Curved hemostat	RRSMRI
Curved mosquito hemostat	RRSMRI
Debakey Forceps (Long)	Teleflex	351804
Debakey Forceps (Narrow)	Teleflex	351802
Debakey Forceps (Rg)	Teleflex	351800
Echo probe cover	Civco
Endotracheotube	Stevens	180-112082055	Rusch Murphy Eye Low Press. Cuff
Iris Spring scissors	Fisher Scientific	NC0127560
iSTAT 1 blood gas analyzer	Abbott Laboratories		MN:300-G
iSTAT CG4+ cartridges	Abbott Laboratories	03P85-50
Kelly Hemostat	Fine Science Tools	1301914
Kocher forceps	RRSMRI
Large Army/Navy Retractor	RRSMRI
Laryngoscope	MACO CE Miller#4 Blade	LA6226-4	Macolaryngoscope.com
Liga-clip applicator L	Ethicon	LC430
Liga-clip applicator M	Ethicon	LX210
Liga-clip applicator S	Ethicon	LX110
Metal suction tip	RRSMRI
Metzenbaum Scissors (Lg)	RRSMRI
Metzenbaum Scissors (Md)	RRSMRI
Mixter - long/mid wide	RRSMRI
Mixter - long/narrow	RRSMRI
Mixter - long/wide	RRSMRI
Mixter - short/narrow	RRSMRI
Needle Driver 10"	RRSMRI
Needle Driver 6"	RRSMRI
Needle Driver 7"	RRSMRI
Philips iE33 Echocardiography machine	Philips		X7 and S12 probes
pressure line tubing and 3-way stopcock	Dr. Freed lab
Rat tooth forcep	RRSMRI
silastic reinforced sheeting	Bioplexus	SH-21001-040	6" x 8" x .040" Gloss
Small Army/Navy Retractor	RRSMRI
Straight hemostat	RRSMRI
Straight mosquito hemostat	RRSMRI
Sutures: 4-0 and 5-0 synthetic, non-absorbable suture, 2-0 silk	Dr. Freed lab
Towel clamp	RRSMRI
vascular tourniquet	Dr. Freed lab
Weitlaner retractor (Md)	RRSMRI
Weitlaner retractor (Sm)	RRSMRI
Zoll R Series Monitor Defibrillator	Zoll technologies