Endothelin inhibitors lower pulmonary vascular resistance and improve functional capacity in patients with Fontan circulation.

Agnoletti G, Gala S, Ferroni F, Bordese R, Appendini L, Pace, Napoleone C, Bergamasco L;

J Thorac Cardiovasc Surg. 2017 Jun;153(6):1468-1475. doi:
10.1016/j.jtcvs.2017.01.051. Epub 2017 Feb 10.

Comment in
J Thorac Cardiovasc Surg. 2017 Jun;153(6):1476-1478.
J Thorac Cardiovasc Surg. 2017 Jun;153(6):1466-1467.

OBJECTIVES: To evaluate the effects of endothelin inhibitors (ERAs) on
hemodynamic and functional parameters in patients post-Fontan procedure with high
pulmonary vascular resistance (PVR).
METHODS: Among our cohort of patients with Fontan circulation, 8 children, 8
adolescents, and 8 adults had PVR ≥2 WU*m2. These patients were treated with ERAs
(minors with bosentan, adults with macitentan) and reevaluated after 6 months.
Pre- and posttreatment hemodynamic variables were assessed by cardiac
catheterization. Functional capacity was evaluated by cardiopulmonary exercise
testing (CPET). Our primary endpoint was to obtain a reduction of PVR; the
secondary endpoint was to obtain an improvement of functional capacity.
RESULTS: Under treatment, New York Heart Association class improved for
adolescents and adults. PVR decreased (P = .01) in all groups: in children from
the median value 2.3 (interquartile range 2.0-3.1) to 1.9 (1.4-2.3) WU*m2, in
adolescents from 2.3 (2.1-2.4) to 1.7 (1.4-1.8) WU*m2, and in adults from 2.8
(2.0-4.7) to 2.1 (1.8-2.8)WU*m2. In 71% of patients, PVR fell to less than 2
WU*m2. Cardiac index increased in adolescents from 2.6 (2.4-3.3) to 3.6 (3.4-4.3)
L/min/m2, P = .04, and in adults from 2.1 (2.0-2.3) to 2.8 (2.3-4.7) L/min/m2,
P = .03. CPET showed that only adolescents displayed a significant functional
improvement. Anaerobic threshold improved from 17 (13-19) to 18 (13-20)
mL/kg/min, P = .03; oxygen consumption and VO2 max increased from 1.3 (1.0-1.6)
to 1.7 (1.1-1.9) L/min, P = .02 and from 25 (21-28) to 28 (26-31) L/min, P = .02,
respectively. Oxygen pulse increased from 7.9 (5.7-10.4) to 11.2 (8.2-13.0)
L/beat, P = .01.
CONCLUSIONS: This is the first study that assesses by cardiac catheterization and
CPET the effects of ERA in patients with Fontan circulation with increased PVR.
These results suggest that ERAs might provide most pronounced hemodynamic and
functional improvement in adults and adolescents.