Objectives: In patients after heart transplantation (HT), systemic arterial hypertension and
enhanced central aortic stiffness are suspected to increase ventricular afterload
which might contribute to graft dysfunction. The aim of our study was to characterize
systemic arterial elastance and its impact on LV function and ventricular–arterial
(V-A) coupling in a cohort of children, adolescents, and young adults after HT using
invasive conductance catheter technique.
Methods: Thirty HT patients (median age: 19.0, [10.8–39.7] years, seven females) underwent
invasive cardiac catheterization including pressure–volume loop analysis. Load-independent
parameters of systolic (Ees) and diastolic (Eed) function, as well as systemic arterial
elastance (Ea; end-systolic pressure/stroke volume) and V-A coupling (Ea/Ees) were
assessed at baseline level and during dobutamine infusion (10 μg/kg/min).
Result: Ees showed an appropriate increase under inotropic stimulation from 0.43 (0.11–2.52)
to 1.0 (0.20–5.1) mm Hg/mL/m2 (p < 0.0001) while Eed remained rather unchanged (0.16 ± 0.10 to 0.12 ± 0.07 mm Hg/mL/m2; p = 0.10). V-A coupling Ea/Ees was abnormal at rest and did not improve significantly
under dobutamine (2.0 ± 1.5–1.6 ± 1.2, p = 0.43) due to a simultaneous rise in Ea from 0.78 ± 0.47 to 1.32 ± 0.70 mm Hg/mL/m2 (p < 0.0001). Both Ees and Eed were significantly associated with Ea at baseline and
under dobutamine infusion.
Conclusion: HT patients show impaired V-A coupling at rest and under inotropic stimulation despite
preserved LV contractile reserve. An abnormal response in vascular function resulting
in increased afterload seems to represent an important factor that may play a role
for the development of late graft failure.
