Evaluating the efficacy of balloon pulmonary angioplasty using quantitative analysis of SPECT pulmonary ventilation/perfusion scintigraphy in patients with chronic thromboembolic pulmonary hypertension

Background: Single -photon emission computed tomography (SPECT) ventilation perfusion imaging is the main imaging method for the diagnosis of pulmonary embolism, and its application in the diagnosis and efficacy evaluation of chronic thromboembolic pulmonary hypertension (CTEPH) has been paid more and more attention. In recent years, with the development of computer software technology, ventilation/perfusion (V/Q) imaging quantitative analysis technology has become more and more mature. The objective of this study was to investigate the utility of quantitative analysis of pulmonary V/Q scintigraphy in evaluating the efficacy of balloon pulmonary angioplasty (BPA) in patients with CTEPH. Methods: In this retrospective analysis, we collected data of patients diagnosed with CTEPH who underwent BPA at the China-Japan Friendship Hospital from April 2018 to September 2020. The sample consisted of 23 males and 28 females, with an average age of 55.1 +/- 12.7 years. All patients underwent V/ Q scintigraphy within one week before surgery, and we reviewed the pulmonary angiography within 1-3 months following the last BPA procedure. We repeated V/Q scintigraphy within 1 week before or after the pulmonary angiography, at the time of collecting clinical and hemodynamic parameters of these patients. We divided the patients into two groups based on the presence of residual pulmonary hypertension postsurgery and compared the pre- and post-operative quantitative pulmonary perfusion defect percentage scores (PPDs%) using the t-test. Results: In all, 102 V/Q scintigraphy scans were performed in 51 patients. The quantitative PPDs% were positively correlated with the hemodynamic indexes mean pulmonary arterial pressure (mPAP), pulmonary vascular resistance (PVR), and mean right ventricular pressure (RVP) (r=0.605, 0.391, and 0.464, respectively, all P<0.001) and negatively correlated with the 6 -minute walking distance (6MWD) (r=-0.254, P=0.010). The average preoperative quantitative PPDs% were (49.0 +/- 15.6)% which significantly decreased to (33.5 +/- 13.9)% after surgery (t=11.249, P<0.001). The preoperative quantitative PPDs% were (54.7 +/- 15.7)% and (44.0 +/- 13.8)% in the residual pulmonary hypertension group and the non -residual pulmonary hypertension group, respectively (t=2.599, P=0.012). The postoperative quantitative PPDs% were (41.5 +/- 12.5)% and (26.3 +/- 11.0)%, in the residual pulmonary hypertension group and the non -residual pulmonary hypertension group, respectively (t=4.647, P<0.001). Conclusions: In this study, we found that quantitative analysis of SPECT pulmonary V/Q scintigraphy adequately reflected the pulmonary artery pressure and clinical status in patients with CTEPH. Our results demonstrate its definite utility in predicting residual pulmonary hypertension and in evaluating the postoperative efficacy of BPA in patients with CTEPH.