MYOCARDIAL INACTIVATION OF THYROID HORMONES IN PATIENTS WITH AORTIC STENOSIS

[helvella]

Maybe the heart doctors will become better thyroid doctors than the endocrinologists?

Thyroid. 2017 Jan 17. doi: 10.1089/thy.2016.0514. [Epub ahead of print]

MYOCARDIAL INACTIVATION OF THYROID HORMONES IN PATIENTS WITH AORTIC STENOSIS.

Paolino B1, Pomerantzeff PM2, Dallan LA3, Gaiotto FA4, Zanini Preite N5, Latronico AC6, Nicolau JC7, Bianco AC8, Giraldez R9.

Author information

1Sao Paulo, Brazil ; [e-mail].

2Sao Paulo, Brazil ; [e-mail].

3Sao Paulo, Brazil ; [e-mail].

4Sao Paulo, Brazil ; [e-mail].

5Chicago, United States ; [e-mail].

6Sao Paulo, Brazil ; [e-mail].

7Sao Paulo, Brazil ; [e-mail].

8Rush University Medical Center, Cohn Research Building , 1735 W. Harrison Street , Suite 212 , Chicago, Illinois, United States , 60612 ; [e-mail].

9Sao Paulo, Brazil ; [e-mail].

Abstract

OBJECTIVE:

To study myocardial thyroid hormone metabolism in patients with aortic valve stenosis (AS) undergoing aortic valve replacement and in patients with coronary artery disease (CAD) undergoing coronary artery bypass grafting surgery.

CONTEXT:

The human heart expresses the type 2 deiodinase (D2) that activates T4 to T3. At the same time, the inactivating type 3 deiodinase (D3) has been found in a rat model of right ventricular hypertrophy. It is not known whether the human myocardium metabolizes thyroid hormone.

DESIGN:

Myocardial thyroid hormone metabolism was assessed by analyzing the difference in serum thyroid hormone levels between the aortic root (incoming blood) and the coronary sinus (outgoing blood) of patients undergoing cardiac surgery.

PATIENTS:

23 patients with AS and 35 patients with CAD.

MEASUREMENTS:

pre-surgical echocardiogram; pre-, during and post-surgical thyroid hormone serum levels in the myocardial and peripheral circulations.

RESULTS:

patients with AS exhibited the expected left ventricle (LV) hypertrophy, i.e. 20-30 % increase in LV posterior wall and interventricular septum thickness and an about 10% increase in AS in LV diastolic diameter. Immediately before cardiopulmonary bypass, blood flowing through the AS myocardium exhibited a 4.6% reduction in T3 and 6.9% increase in rT3 levels, decreasing the serum T3/rT3 ratio by 9.6%. T4 and TSH serum levels remained similar between the aortic root and coronary sinus. In contrast, no myocardial thyroid hormone metabolism was observed in CAD patients. Notably, the AS myocardium lost the ability to inactivate thyroid hormone after cardiopulmonary bypass, possibly due to myocardial stunning.

CONCLUSIONS:

there is accelerated thyroid hormone inactivation in the AS myocardium, which is likely the result of D3 expression. No evidence to suggest thyroid hormone activation in the myocardium was obtained in the present study.

PMID: 28095748

DOI: 10.1089/thy.2016.0514

ncbi.nlm.nih.gov/pubmed/280...

Rest of paper behind paywall - OK for millionaires, the rest of us can't afford it.

[Gcart]

Hi maybe nothing to do with it but, I had been followed up for a leaky valve in my heart for 4 yrs with it getting slightly worse.

1 yr ago February I had TT for cancer , when I went for my usual echo in April and then to see the cardiologist he told me there was no evidence of the leak now!!

Is there any connection ??!! Maybe

Whilst they say you don't have symptoms before thyroid cancer , I am convinced that I did I was so tired and having collapsing episodes when walking , just couldn't recover from any exertion. Bad stomach aches etc.

Could it be more stable hormones, I am doing a bit better than afore mentioned

[helvella Administrator Thyroid UK in reply to Gcart]

Very interesting ideas.

I am convinced that the way that thyroid hormone affects our organs is going to be very much more complicated and subtle than we currently appreciate. The mere idea that we can dynamically measure the effect of an organ on thyroid hormone levels is quite incredible.

[Numberone1]

Can anyone actually explain what this means please?

[helvella Administrator Thyroid UK in reply to Numberone1]

This is a link to a description of aortic stenosis (AS):

heart.org/HEARTORG/Conditio...

In someone suffering AS, the amount of T3 available is lower than in those not suffering AS. This is because of a higher rate of inactivation of T3. No conversion of T4 to T3 takes place in the area of investigation - that is, to a considerable extent the muscle of the heart has to rely of incoming T3 in the blood.

This raises the possibility that thyroid hormone could have a role in some heart disease.