In adults with Fontan circulation, resting hemodynamic measures may not fully explain differences in long-term outcomes, particularly during physical stress. In the European Heart Journal, a retrospective cohort study evaluated whether pulmonary vascular resistance index (PVRI) response to exercise predicted clinical outcomes in adults after Fontan palliation.

The analysis included 88 adults aged 18 years or older who underwent supine cycling exercise cardiac catheterization. Mean age at catheterization was 32.2 ± 8.8 years, and 45.5% of the cohort were female. Patients were categorized by absence (n = 23) or presence (n = 65) of an exercise-induced reduction in PVRI. Resting PVRI measured 1.9 ± 0.9 Wood units–square meter, while exercise PVRI was 1.2 with an interquartile range of 0.8 to 2.1 Wood units–square meter. Clinical, biochemical, and echocardiographic parameters showed no association with PVRI response to exercise.

During a mean follow-up of 2.2 ± 1.4 years, resting PVRI was not associated with the composite endpoint of death or transplantation (hazard ratio [HR] 0.95 per Wood unit–square meter, 95% confidence interval [CI] 0.52-1.74; P = 0.86). In contrast, exercise PVRI was associated with outcomes (HR 2.15 per Wood unit–square meter, 95% CI 1.24-3.73; P = .007) and remained predictive after adjustment for exercise pulmonary artery wedge pressure (HR 2.08, 95% CI 1.19-3.62; P = .01) or individual clinical risk factors. Two-year event-free survival was lower in patients without exercise-induced PVRI reduction compared with those with a reduction (67% vs 95%; P < .001).

Exercise PVRI response provided prognostic information beyond resting invasive hemodynamic data in adults after Fontan palliation.