Cardiovascular remodeling after AVF surgery in rats assessed by a clinical MRI scanner.
OBJECTIVE
To evaluate a cardiovascular magnetic resonance imaging (MRI) technique which allows the longitudinal analysis of cardiovascular remodeling in a rodent femoral arteriovenous fistula (AVF) model by means of a clinical scanner.


METHODS
Eight rats underwent femoral AVF surgery and four rats served as controls. Vascular and cardiac morphology as well as cardiac function was assessed from Week 3 to 12 using contrast-enhanced, time-resolved magnetic resonance angiography (MRA) and cardiac MRI (cine gradient-echo sequence) at 3 T in one imaging session.


RESULTS
Arteriovenous surgery resulted in progressive venous dilation and a subsequent cardiac adaptation. This procedure led to downstream vasodilation of the iliac vein and inferior vena cava of 179% and 188%, respectively (3 weeks). To accommodate the increased returning blood volume, cardiac output (CO) increased significantly (P=.014; 6 weeks). This was caused by increased end-diastolic volume (EDV), stroke volume (SV) and heart rate (HR) consistent with an increased volume load. A continuous increase in heart weight peaked at 12 weeks. This increase combined with a distinct end-diastolic left ventricular dilation implied eccentric hypertrophy.


CONCLUSIONS
Small rodent MRI is feasible and clearly depicts fistula maturation and cardiac alterations. This technique proved to be a valuable tool for longitudinal in vivo monitoring in this model, which strongly resembles clinical findings in hemodialysis patients.
Langer
Stephan
S
Department of Vascular Surgery, University Hospital Aachen, Aachen 52074, Germany. slanger@ukaachen.de
Paulus
Niklas
N
Heiss
Christian
C
Koeppel
Thomas A
TA
Greiner
Andreas
A
Buhl
Alexandra
A
Lauer
Thomas
T
Kokozidou
Maria
M
Jacobs
Michael J
MJ
Krombach
Gabriele A
GA
D000818:Animals; D001166:Arteriovenous Shunt, Surgical; D005260:Female; D006352:Heart Ventricles / Q000033:anatomy & histology*; D008279:Magnetic Resonance Imaging / Q000379:methods*; D011379:Prognosis; D051381:Rats; D017207:Rats, Sprague-Dawley; D016896:Treatment Outcome; D020257:Ventricular Remodeling / Q000502:physiology*