The use of 2-dimensional parametric parenchymal blood flow (2D-PPBF) is feasible for improving the monitoring and measurement of perfusion changes associated with balloon pulmonary angioplasty (BPA) in the treatment of chronic thromboembolic pulmonary hypertension.

Investigators retrospectively evaluated 18 patients who underwent 35 consecutive interventions with 98 treated pulmonary arteries. Software was used to postprocess the acquired digital subtraction angiography (DSA) series and quantify pulmonary blood flow changes with 2D-PPBF. Arterial inflow, a designated reference region of interest (ROI) in the treated pulmonary artery, as well as a distal target ROI were positioned in regions on DSA prior to and after BPA. The researchers evaluated the half-peak density (HPD), wash-in rate (WIR), arrival to peak (AP), area under the curve (AUC), and mean transit time (MTT).

Following BPA, there was a significant improvement in the pulmonary flow grade score in the cohort (1 vs 3; P <.0001). There were also significant decreases in the mean HPDparenchyma/HPDinflow (-10.2%; P <.0001), APparenchyma/ APinflow (-24.4%; P =.0007), and MTTparenchyma/MTTinflow (-3.5%; P =.0449) ratios after BPA. Increases in WIRparenchyma/WIRinflow (82.4%) and AUCparenchyma/AUCinflow (58.6%) ratios were also recorded (P <.0001).

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The use of 2D-PPBF was also able to detect associations between pulmonary flow grade score changes and changes in HPDparenchyma/HPDinflow (P =.04), WIRparenchyma/WIRinflow (P <.0001), APparenchyma/APinflow (P =.03), AUCparenchyma/AUCinflow (P <.0001), and MTTparenchyma/MTTinflow (P <.0001).

Study limitations included the small number of participants, the recruitment of patients from a single institution, the retrospective design, and the relative short-term follow-up.

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“In conclusion,” the researchers wrote, “the evaluated new 2D-PA technique is feasible for the quantification of perfusion changes following BPA and has the potential to improve monitoring of BPA in the interventional suite.”


Maschke SK, Winther HMB, Meine T, et al. Evaluation of a newly developed 2D parametric parenchymal blood flow technique with an automated vessel suppression algorithm in patients with chronic thromboembolic pulmonary hypertension undergoing balloon pulmonary angioplasty [published online March 16, 2019]. Clin Radiol. doi:10.1016/j.crad.2018.12.023