| Intravenous Levothyroxine for Unstable Brain-Dead Heart Donors |
| Design |
Multicenter, parallel-group, randomized trial
N= 838
|
| Objective |
To evaluate the hypothesis that intravenous levothyroxine would increase the rate of hearts transplanted from hemodynamically unstable brain-dead organ donors being considered for heart donation
|
| Study Groups |
Levothyroxine (n= 419)
Placebo (n= 419)
|
| Inclusion Criteria |
Deceased patients aged 14 to 55 years with authorization for organ donation, declared dead according to neurologic criteria, weight ≥45 kg, hemodynamic instability after fluid resuscitation
|
| Exclusion Criteria |
Hearts not considered for transplantation due to known heart disease or if thyroid hormone was received within the past month
|
| Methods |
Subjects were randomized within 24 hours after declaration of death to IV levothyroxine (30 μg/hour for a minimum of 12 hours) or placebo (normal saline). Baseline free T4 levels were obtained before the start of levothyroxine or saline infusion and before organ procurement. The levothyroxine dose could be decreased or discontinued based on prespecified hemodynamic variables (hypertension, tachycardia, or arrhythmias, defined in the trial protocol). Extension of levothyroxine infusion beyond 12 hours was permitted at the discretion of each organ-procurement organization (OPO). Open-label use of levothyroxine was discouraged but permitted in the control group and only after the 12 hours of saline infusion was completed.
|
| Duration |
December 1, 2020, to November 6, 2022 |
| Outcome Measures |
Primary: Transplantation of the donor heart
Secondary: Number of organs transplanted per donor, lungs transplanted, liver transplanted, number of kidneys transplanted per donor, weaning from vasopressor therapy, time to wean off vasopressors, time until first echocardiogram was ordered, donor ejection fraction, adverse events, graft survival at 30 days
|
| Baseline Characteristics |
|
Levothyroxine (n= 419) |
Placebo (n= 419)
|
| Age, years |
36 ± 11 |
36 ± 10 |
| Female |
127/403 (32%) |
153/400 (38%) |
| Weight, kg |
86 ± 24 |
85 ± 23 |
|
Race/ethnic group
White, non-Hispanic
Black
Hispanic or Latino
Asian, Pacific Islander, or other
|
252/403 (63%)
75/403 (19%)
60/403 (15%)
16/403 (4%)
|
278/397 (70%)
49/397 (12%)
63/397 (16%)
7/397 (2%)
|
|
Blood group
O
A
B
AB
|
224 (53%)
134 (32%)
50 (12%)
11 (3%)
|
214 (51%)
148 (35%)
49 (12%)
8 (2%)
|
|
Coexisting conditions
Hypertension
Diabetes
Cigarette use
Cocaine use
|
98/403 (24%)
38/403 (9%)
58/403 (14%)
92/403 (23%)
|
104/397 (26%)
31/397 (8%)
76/397 (19%)
105/397 (26%)
|
|
Cause of death
Anoxia
Stroke
Trauma
Other
|
162/403 (40%)
87/403 (22%)
143/403 (35%)
11/403 (3%)
|
195/397 (49%)
79/397 (20%)
117/397 (29%)
6/397 (2%)
|
| Creatinine level, mg/dL (IQR) |
1.2 (0.9–1.9) |
1.2 (0.8–2.0) |
| Troponin I level, ng/mL (IQR) |
0.7 (0.07–10.2) |
0.7 (0.08–7.3) |
| Hepatitis C positive |
27/403 (7%) |
25/397 (6%) |
| Vasopressor–inotrope score, median (IQR) |
10.2 (5–24) |
10.5 (5–22) |
| Time from declaration of brain death to start of infusion, hr (IQR) |
8.6 (6.3–11.7) |
7.5 (4.9–11.1) |
| Free T4 level, median (IQR), ng/dL |
1.00 (0.77–1.30) |
1.00 (0.77–1.30) |
| Free T4 level below 0.9 ng/dL |
141/370 (38%) |
128/346 (37%) |
| Expected heart yield, median (IQR) |
0.63 (0.15–0.86) |
0.59 (0.15–0.82) |
| Results |
|
Levothyroxine (n= 419) |
Saline (n= 419) |
Risk ratioa or Differenceb (95% CI) |
| Heart transplanted |
230 (54.9%) |
223 (53.2%) |
1.01 (0.97 to 1.07)a |
| No. of organs transplanted per donor, median (IQR) |
4 (3 to 5) |
4 (3 to 5) |
1.03 (0.99 to 1.08)a |
| Lungs transplanted |
163/419 (38.9%) |
149/418 (35.6%) |
1.09 (0.91 to 1.31)a |
| Liver transplanted |
335/419 (80.0%) |
334/418 (79.9%) |
1.00 (0.92 to 1.09)a |
| No. of kidneys transplanted per donor (95% CI) |
1.69 (1.61 to 1.77) |
1.64 (1.58 to 1.70) |
1.03 (0.99 to 1.08)a |
| Weaned off vasopressors at 12 hr |
143/404 (35.4%) |
152/388 (39.2%) |
0.91 (0.79 to 1.04)a |
| Time to wean off vasopressors, hr (95% CI) |
22 (19 to 31) |
25 (19 to 38) |
1.07 (0.89 to 1.29)a |
| Time until first echocardiogram was ordered, hr (95% CI) |
12 (11 to 13) |
13 (12 to 14) |
1.09 (0.93 to 1.27)a |
|
Left ventricular ejection fraction, %
First echocardiogram
Maximum of all echocardiograms
|
59 ± 11
60 ± 9
|
58 ± 12
60 ± 10
|
1.0 (-0.6 to 2.7)b
0.5 (-0.9 to 2.0)b
|
| Any adverse event |
51 (12.2%) |
16 (3.8%) |
8.4 (4.7 to 12.0)b |
| Serious adverse event |
2 (0.5%) |
3 (0.7%) |
-0.2 (-1.3 to 0.8)b |
| Graft survival at 30 days |
224/230 (97.4%) |
213/223 (95.5%) |
1.9 (-2.3 to 6.0)b |
| Adverse Events |
More donors had adverse events in the levothyroxine group than in the saline group.
Significant differences were observed in the number of cases of severe hypertension (26 vs. 5, p<0.001) and tachycardia (16 vs. 3, p= 0.003).
The incidence of serious adverse events was similar in the two groups.
|
| Study Author Conclusions |
In hemodynamically unstable brain-dead potential heart donors, intravenous levothyroxine infusion did not result in significantly more hearts being transplanted than saline infusion.
|
| Critique |
The study was well-designed with a large sample size and multicenter approach, providing robust data on the efficacy of levothyroxine in this context. However, the lack of blinding and the allowance for open-label use of levothyroxine in the control group could introduce bias. Additionally, the study did not find a significant benefit of levothyroxine, which challenges current practices based on observational data. The findings are limited to the specific population of hemodynamically unstable brain-dead donors and may not be generalizable to other donor populations.
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