Left Ventricular Ejection Fraction before and after bariatic surgery

In the medical world it is known that there are multiple pathophysiological
processes within the body of morbid obese patients. Due to these processes
people gain significantly amounts of weight which can cause changes in
metabolism. One of the best known change is de progressive resistance to
insulin which cause (non) insulin dependent diabetes mellitus type II. It is
also proven that obesity causes hypertrophy of the left ventricle of the heart
and a diminished left ventricular ejection fraction (LVEF) and more cardiac
morbidity and mortality.

To objectivate cardial (dys)function there has to be a validated method to
measure one of the most important functional paremeters: LVEF.
There are multiple methods like trans thoracic sonography, transesophageal
sonography, nuclair imaging and MRI. The method of choice is proven to be an
MRI of the heart, which (somestimes with the help of iv-contrast) can measure
functional parameters, dimensions of the left ventricle, left ventricular mass,
left ventricular ejection fraction and other (patho)physiological processes.

Bariatric surgery triggers an post operative recovery of the diminished left
ventricular function and causes a decrease of mass and diameter of the left
ventricle, thus a decrease of left ventricular hypertrofy and a increase of
LVEF. In this proces, the decrease in BMI seems to be correlated with the
amount of decrease in left ventricular mass. After one year there could be a
total recovery of diastolic and systolic dysfunction and aortic compliance. The
glucose metabolism can even recover significantly to recover completely after
substantial weight loss.

Possible explenations of improvement in LVEF may concern a regression of direct
toxic effects in adipose patient upon cardiomyocyts and an improved
haemodynamics after weight loss. These improvements can be of such order it may
provide a alternative for heart transplant in extreme obese patients.

Annually a total of 400 bariatric surgeries is performed at Maasstad Hospital,
Rotterdam, The Netherlands. Mostly it concerns a sleeve gastrectomy or a
Roux-en-Y gastric bypass. The most post operative finding is loss of body
weight, but also a drop in insulin resitance is seen.

Primary objective:
Increase in left ventricular ejection fraction after bariatic surgery

Secundary objectives:
Reduction of paracardial fat after bariatic surgery
Reduction of visceral abdominal fat after bariatic surgery
Reduction of hepatic steosis after bariatic surgery
Increase in compliance of the thoracic aorta
Anthropometric measurements before and after bariatic surgery
Differences in measurements between the types of bariatic surgery

The study will be prospective observational amongst obese patients who are
qualified for bariatric surgery. A MRI of the heart will be performed once
before surgery and three times after bariatic surgery (3, 6, 12 monhs). With
each MRI, blood samples will be taken to investigate the relation of chemical
and endocrinological processes in relation with the left ventricular ejection
function.

Burden:
1. Four times a MRI of the heart (once before bariatric surgery, three times
after batiatric surgery after 3, 6 and 12 months).
2. Fout times blood samples (with a maximum of 4 times 10 cc)

Risks:
1. Sensations when stepping into the magnetic field of the MRI (iron taste,
vertigo)
2. Small haematoma after a vena punction.