Higher mortality after coronary-artery surgery
in women treated with thyroxine than other women
(March 2003)
The background of the study. Patients
with hypothyroidism may also have coronary artery disease, and need
coronary-artery bypass grafting. The short-term outcome of this
operation was compared in patients with hypothyroidism receiving
long-term thyroxine (T4) therapy and other patients.
How the study was done. Between
1993 and 2000, 606 women and 3025 men underwent coronary-artery
bypass grafting at the Hammersmith Hospital in London, England.
They included 30 women and 28 men with a history of hypothyroidism
who were being treated with T4. The characteristics and the surgical
details in these 58 women and men were compared, and their 30-day
mortality rates were compared with the rates in the other women
and men.
The results of the study. The characteristics
of the women and men treated with T4 were similar, except that the
women had a slightly higher mean serum free T4 concentration, more
were taking a diuretic drug, and the operation took longer in the
women.
Among the 58 T4-treated hypothyroid patients, there were 6 deaths
(5 women, 1 man) within 30 days after surgery. The mortality rate
in the 30 women (17 percent) was statistically significantly higher
than in the other 576 women (6 percent). The mortality rate in the
T4-treated hypothyroid men (4 percent) was similar to that in the
other 2997 men (3 percent). Four of the women and the 1 man died
of progressive heart failure; the other woman died of an arrhythmia.
Among the women with hypothyroidism, independent variables associated
with death were lower T4 dose and diuretic therapy.
The conclusions of the study. Short-term
mortality after coronary-artery bypass graft surgery is higher in
women with hypothyroidism receiving T4 therapy than in other women.
The original article. Zindrou D,
Taylor KM, Bagger JP. Excess coronary artery bypass graft mortality
among women with hypothyroidism. Ann Thorac Surg 2002;74:2121-5.
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