Chronic thromboembolic pulmonary hypertension: Evaluation of 2D-perfusion angiography in patients who undergo balloon pulmonary angioplasty.

OBJECTIVE: To evaluate the feasibility of 2D-perfusion angiography (2D-PA) in order to quantify perfusion changes of the lung parenchyma pre- and post-balloon pulmonary angioplasty (BPA).
METHODS: Thirty consecutive interventions in 16 patients with 99 treated pulmonary artery segments were included. To quantify changes in pulmonary blood flow using 2D-PA, the acquired digital subtraction angiographies (DSA) pre- and post-BPA were post-processed. A reference ROI in the treated pulmonary artery and a distal target ROI in the lung parenchyma were placed in corresponding areas on DSA pre- and post-BPA. Time to peak (TTP), peak density (PD) and area under the curve (AUC) were assessed. The ratios reference ROI to target ROI (TTPparenchyma/TTPinflow; PDparenchyma/PDinflow; AUCparenchyma/AUCinflow) were calculated. Relative differences of the 2D-PA parameters were correlated to changes in the pulmonary-flow-grade-score.
RESULTS: The pulmonary-flow-grade-score improved after BPA (p<0.0001). Likewise, the ratio TTPparenchyma/TTPinflow shortened by 10% (p=0.0002), the PDparenchyma/PDinflow increased by 46% (p<0.0001) and the AUCparenchyma/AUCinflow increased by 36% (p<0.0001). A significant correlation between changes in the pulmonary-flow-grade-score and changes in PDparenchyma/PDinflow (ρ=0.48, p<0.0001) and AUCparenchyma/AUCinflow (ρ=0.31, p=0.0018) was observed.
CONCLUSION: Quantification of pulmonary perfusion pre- and post-BPA using 2D-PA is feasible and has the potential to improve monitoring of BPA. KEY POINTS: • Quantification of BPA results by use of 2D-PA is feasible. • 2D-PA allows objective assessment of changes in lung parenchymal perfusion. • 2D-PA has the potential to optimize BPA.