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Respiratory function and oxygenation after balloon pulmonary angioplasty
International Journal of Cardiology 212 (2016) 190–191
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Correspondence
Respiratory function and oxygenation after balloon pulmonary angioplasty Makoto Takei a, Masaharu Kataoka a,⁎, Takashi Kawakami a, Ichiro Kuwahira b, Keiichi Fukuda a a b
Department of Cardiology, Keio University School of Medicine, Tokyo, Japan Department of Pulmonary Medicine, Tokai University Tokyo Hospital, Tokyo, Japan
a r t i c l e
i n f o
Article history: Received 12 January 2016 Received in revised form 14 March 2016 Accepted 16 March 2016 Available online 17 March 2016 Keywords: Balloon pulmonary angioplasty Chronic thromboembolic pulmonary hypertension Oxygenation Respiratory function
Recently, balloon pulmonary angioplasty (BPA), also known as percutaneous transluminal pulmonary angioplasty (PTPA), emerged as a new therapeutic option for patients with chronic thromboembolic pulmonary hypertension (CTEPH), with clinical studies consistently showing improvements in hemodynamic function after BPA [1–4]. Even though the main cause of hypoxemia in patients with CTEPH is ventilation/perfusion mismatch, the associated impairments in lung function are not negligible. However, to our knowledge, no studies have investigated the effects of BPA on respiratory function in patients with CTEPH. Thus, we analyzed changes in respiratory function in patients with CTEPH before and after BPA, and evaluated the correlation between changes in respiratory function and improvements in hemodynamics. We analyzed 59 consecutive patients with CTEPH, who completed BPA sessions from November 2012 to April 2015. BPA was performed with staged sessions, as described previously [5]. Three patients were excluded from this study owing to incomplete results from the pulmonary function tests, and one patient with apparent lung disease detected with chest computed tomography (fibrosis after thoracic empyema) was also excluded. No patients had a history of smoking or asthma. The remaining 55 patients were enrolled in the study (16 men and 39 women). All patients underwent pulmonary function testing and right heart catheterization just before the first BPA session and within
⁎ Corresponding author at: Department of Cardiology, Keio University School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo 160-8582, Japan. E-mail address: [email protected] (M. Kataoka).
http://dx.doi.org/10.1016/j.ijcard.2016.03.061 0167-5273/© 2016 Elsevier Ireland Ltd. All rights reserved.
2 weeks after the final session. Measurements of pulmonary function testing were conducted in accordance with the American Thoracic Society recommendations [6,7], using a Multi-Functional Spirometer HI-801 and CHESTAC-9800 (CHEST Inc. Tokyo, Japan). Each parameter was presented as a percentage of the predicted value based on Global Lung Initiative equations. In addition, dead space ventilation fraction, VD/VT, which reflects ventilation/perfusion inequality, was calculated according to Bohr's equation: VD/VT = (PaCO2 − PetCO2) / PaCO2. PetCO2 was measured with an end-tidal carbon dioxide monitor, TG-920P (NIHON KOHDEN, Tokyo, Japan). Since starting PetCO2 measurements in January 2014, we have tested 22 patients. Alveolar-arterial oxygen gradient was calculated according to the results of blood gas testing. Table 1 shows the baseline characteristics of enrolled 55 patients. All patients were treated with comprehensive therapy including anticoagulant therapy and home-oxygen therapy. Over 80% (45 out of 55) of patients had WHO functional class III or IV at baseline, suggesting that the majority of this study population had clinically moderate to severe CTEPH. The mean number of BPA sessions conducted per patient was 6.05 (range, 2 to 13 sessions). A total of 20 hemoptysis events were observed out of 333 BPA sessions, and none required mechanical ventilation. No treatment-related death occurred. Hemodynamic parameters and B-type natriuretic peptide improved significantly after BPA (Table 2). Importantly, 53 out of 55 enrolled patients achieved target mean pulmonary arterial pressure (PAP) below 25 mm Hg, and mean PAP of other 2 patients were 26 and 28 mm Hg after final session, suggesting BPA could give a great benefit to improve pulmonary hypertension. The results of pulmonary function testing are shown in Table 2. Fundamental parameters of pulmonary function testing such as vital capacity (VC), forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1) increased significantly after BPA (all P b 0.01). Regarding to spirometric parameters, V50 increased significantly after BPA (P b 0.01), but V25 and V50/V25 did not change significantly (P = 0.47 and P = 0.62, respectively). Furthermore, total lung capacity (TLC), functional residual capacity (FRC), and peak expiratory flow (PEF) were improved significantly after BPA (P b 0.01, P = 0.01, and P b 0.01, respectively). The 95% confidence intervals for changes between before and after BPA were 1.0–4.2 (% predicted value) for TLC, 0.7–5.9 (% predicted value) for FRC, and 1.7–11.0 (% predicted value) for PEF. On the other hand, residual volume, FEV1/FVC, and diffusing capacity for carbon monoxide did not change significantly (P = 0.63, P = 0.52, and P = 0.62, respectively).
M. Takei et al. / International Journal of Cardiology 212 (2016) 190–191 Table 1 Baseline characteristics in enrolled patients. Variable (n = 55) Female, n (%) Age, years WHO-FC; I/II/III/IV, n Height, cm Weight, kg BMI, kg/m2 Post PEA, n (%) Medications Endothelin receptor antagonist, n (%) Oral prostacyclin analogue, n (%) Phosphodiesterase 5 inhibitor, n (%)
39 (70.9%) 65 [54 to 76] 0/10/41/4 158.3 [151.5 to 164.8] 54 [45.8 to 67.4] 21.9 [19.2 to 25.3] 6 (10.9%) 24 (43.6%) 24 (43.6%) 37 (67.3%)
Values are expressed as median [25th to 75th percentiles] for continuous variables, and as number and percentage for categorical variables. WHO-FC, world health organization functional class; BMI, body mass index; and PEA, pulmonary endarterectomy.
TLC is positively affected by inspiratory muscle strength, and negatively regulated by lung and chest wall elastic contractile power, while FRC is positively affected by chest wall elastic extension power, and negatively regulated by lung elastic contractile power. Since chest wall and respiratory muscle power are probably unaffected by BPA, the elevations of both TLC and FRC in this study suggested improvements in lung compliance.
Table 2 Hemodynamics and respiratory functional changes with balloon pulmonary angioplasty (BPA). Variable (n = 55)
Before BPA
After BPA
P value
Hemodynamic indices WHO-FC; I/II/III/IV, n Mean PAP, mm Hg Cardiac index, L/min PVR, dyne·sec·cm−5 BNP, pg/ml
0/10/41/4 37 [31 to 47] 2.0 [1.8 to 2.4] 661 [439 to 1018] 70.0 [24.4 to 286.9]
32/23/0/0 20 [16 to 22] 2.2 [1.9 to 2.6] 288 [204 to 340] 24.8 [14.8 to 47.0]
b0.01⁎ b0.01⁎ 0.04⁎ b0.01⁎ b0.01⁎
Respiratory indices TLC, % predicted VC, % predicted FRC, % predicted RV, % predicted FVC, % predicted FEV1, % predicted PEF, % predicted FEV1/FVC, % predicted V50 V25 V50/V25 DLCO, % predicted VD/VT (n = 22)
88.0 [79.5 to 96.0] 92.8 [83.4 to 101.3] 88.5 [76.4 to 103.1] 86.4 [72.4 to 100.0] 96.6 [85.8 to 106.2] 84.9 [75.2 to 94.0] 92.3 [78.2 to 106.5] 87.3 [83.1 to 93.9] 1.59 [1.16 to 2.54] 0.34 [0.22 to 0.67] 4.61 [3.44 to 5.73] 45.0 [37.0 to 52.1] 0.33 [0.29 to 0.37]
90.0 [81.1 to 99.7] 96.2 [88.9 to 106.0] 90.3 [81.3 to 102.3] 88.7 [77.6 to 100.1] 99.0 [92.1 to 108.2] 90.8 [80.6 to 100.1] 99.5 [86.0 to 108.8] 90.5 [82.1 to 94.1] 1.85 [1.31 to 2.63] 0.39 [0.23 to 0.64] 4.59 [4.03 to 5.91] 45.1 [37.1 to 52.8] 0.28 [0.17 to 0.31]
b0.01⁎ b0.01⁎ 0.01⁎ 0.63 b0.01⁎ b0.01⁎ b0.01⁎ 0.52 b0.01⁎ 0.47 0.62 0.62 b0.01⁎
Blood gas testing PaCO2 PaO2 HCO− 3 Base excess SaO2 AaDO2
38.1 [34.2 to 41.3] 55.7 [51.5 to 66.1] 25.6 [23.8 to 27.9] 1.70 [−0.30 to 3.85] 90.8 [87.5 to 93.5] 45.8 [35.1 to 51.4]
40.7 [38.4 to 43.6] 70.3 [62.0 to 79.1] 27.3 [25.0 to 29.0] 3.05 [1.10 to 4.80] 95.4 [93.1 to 96.5] 28.2 [23.3 to 34.2]
b0.01⁎ b0.01⁎ b0.01⁎ b0.01⁎ b0.01⁎ b0.01⁎
191
Changes in TLC, VC, FRC, and FVC were significantly correlated with changes in pulmonary vascular resistance (PVR), respectively (Spearman's ρ = 0.42 for correlation between TLC and PVR, P b 0.01; Spearman's ρ = 0.52 for correlation between VC and PVR, P b 0.01; ρ = 0.34 for correlation between FRC and PVR, P = 0.01; Spearman's ρ = 0.44 for correlation between FVC and PVR, P b 0.01), suggesting an association between reperfusion of pulmonary arteries and respiratory function restoration. In addition, the marker for ventilation/perfusion inequality, VD/VT, improved significantly after BPA from a median of 0.33 before BPA to 0.28 after BPA (P b 0.01), indicating that the newly acquired ventilation spaces were efficiently perfused. Alveolar-arterial oxygen gradient also significantly improved after BPA (P b 0.01). Furthermore, the results of blood gas testing demonstrated the significant improvements of partial pressure of arterial oxygen and oxygen saturation. These findings suggest that BPA improved gas exchange efficiency in patients with CTEPH. There are study limitations in this study. Even though we showed the correlation between changes in PVR and changes in lung function such as TLC, the mechanisms by which pulmonary artery reperfusion with BPA restores lung function are unclear. Considering previous reports showing an association between lung parenchymal scaring and lung volume reduction in patients with CTEPH, it is possible that lung reperfusion may restore residual ischemic lung tissues [8]. A higher incidence of acute lung reperfusion injury after balloon angioplasty of branch pulmonary artery stenosis has been reported [9], and it would be desirable to consider the association between acute lung reperfusion injury after BPA and respiratory function. Furthermore, alveolar recruitment through increased production of surfactant proteins due to the increased lung perfusion possibly offers another explanation for the elevated lung capacity. However, further studies are needed to adequately elucidate more detailed mechanisms underlying the observed effects. In conclusion, BPA improved respiratory function and oxygenation as well as hemodynamics. The findings in this study suggest BPA can improve both gas exchange efficiency and mechanics of breathing, leading to favorable effects on respiratory function in patients with CTEPH. Disclosure statement The authors have no conflicts of interest to disclose.
Values are expressed as median [25th to 75th percentiles] for continuous variables. Respiratory indices are presented as a percentage of the predicted value, estimated with age, sex, and height. Changes in hemodynamics and respiratory parameters before and after BPA were analyzed with Wilcoxon's signed-rank test. mean PAP, mean pulmonary artery pressure; PVR, pulmonary vascular resistance; BNP, brain natriuretic peptide; TLC, total lung capacity; VC, vital capacity; FRC, functional residual capacity; RV, residual volume; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 s; PEF, peak expiratory flow; DLCO, diffusing capacity for carbon monoxide; PaCO2, partial pressure of arterial carbon dioxide; PaO2, partial pressure of arterial oxygen; SaO2, oxygen saturation; AaDO2, alveolar-arterial oxygen gradient. ⁎ P b 0.05.
References [1] M. Kataoka, T. Inami, K. Hayashida, et al., Percutaneous transluminal pulmonary angioplasty for the treatment of chronic thromboembolic pulmonary hypertension, Circ Cardiovasc Interv 5 (2012) 756–762. [2] T. Inami, M. Kataoka, N. Shimura, et al., Pulmonary edema predictive scoring index (PEPSI), a new index to predict risk of reperfusion pulmonary edema and improvement of hemodynamics in percutaneous transluminal pulmonary angioplasty, JACC Cardiovasc Interv 6 (2013) 725–736. [3] T. Inami, M. Kataoka, N. Shimura, et al., Pressure-wire-guided percutaneous transluminal pulmonary angioplasty: a breakthrough in the catheter-interventional therapy for chronic thromboembolic pulmonary hypertension, JACC Cardiovasc Interv 7 (2014) 1297–1306. [4] T. Inami, M. Kataoka, M. Ando, K. Fukuda, H. Yoshino, T. Satoh, A new era of therapeutic strategies for chronic thromboembolic pulmonary hypertension by two different interventional therapies; pulmonary endarterectomy and percutaneous transluminal pulmonary angioplasty, PlosOne 9 (2014) e94587. [5] T. Tsugu, M. Murata, T. Kawakami, et al., Significance of echocardiographic assessment for right ventricular function after balloon pulmonary angioplasty in patients with chronic thromboembolic induced pulmonary hypertension, Am J Cardiol 115 (2015) 256–261. [6] Standardization of Spirometry, Update. American Thoracic Society, Am J Respir Crit Care Med 1995 (152) (1994) 1107–1136. [7] American Thoracic Society. Single-breath carbon monoxide diffusing capacity (transfer factor). Recommendations for a standard technique — 1995 update, Am J Respir Crit Care Med 152 (1995) 2185–2198. [8] T.A. Morris, W.R. Auger, M.Z. Ysrael, et al., Parenchymal scarring is associated with restrictive spirometric defects in patients with chronic thromboembolic pulmonary hypertension, Chest 110 (1996) 399–403. [9] S. Yacouby, M. Meador, E. Mossad, Lung reperfusion injury in patients after balloon angioplasty for pulmonary artery stenosis, J Cardiothorac Vasc Anesth 28 (2014) 502–505.
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Correspondence
Respiratory function and oxygenation after balloon pulmonary angioplasty Makoto Takei a, Masaharu Kataoka a,⁎, Takashi Kawakami a, Ichiro Kuwahira b, Keiichi Fukuda a a b
Department of Cardiology, Keio University School of Medicine, Tokyo, Japan Department of Pulmonary Medicine, Tokai University Tokyo Hospital, Tokyo, Japan
a r t i c l e
i n f o
Article history: Received 12 January 2016 Received in revised form 14 March 2016 Accepted 16 March 2016 Available online 17 March 2016 Keywords: Balloon pulmonary angioplasty Chronic thromboembolic pulmonary hypertension Oxygenation Respiratory function
Recently, balloon pulmonary angioplasty (BPA), also known as percutaneous transluminal pulmonary angioplasty (PTPA), emerged as a new therapeutic option for patients with chronic thromboembolic pulmonary hypertension (CTEPH), with clinical studies consistently showing improvements in hemodynamic function after BPA [1–4]. Even though the main cause of hypoxemia in patients with CTEPH is ventilation/perfusion mismatch, the associated impairments in lung function are not negligible. However, to our knowledge, no studies have investigated the effects of BPA on respiratory function in patients with CTEPH. Thus, we analyzed changes in respiratory function in patients with CTEPH before and after BPA, and evaluated the correlation between changes in respiratory function and improvements in hemodynamics. We analyzed 59 consecutive patients with CTEPH, who completed BPA sessions from November 2012 to April 2015. BPA was performed with staged sessions, as described previously [5]. Three patients were excluded from this study owing to incomplete results from the pulmonary function tests, and one patient with apparent lung disease detected with chest computed tomography (fibrosis after thoracic empyema) was also excluded. No patients had a history of smoking or asthma. The remaining 55 patients were enrolled in the study (16 men and 39 women). All patients underwent pulmonary function testing and right heart catheterization just before the first BPA session and within
⁎ Corresponding author at: Department of Cardiology, Keio University School of Medicine, Shinanomachi 35, Shinjuku-ku, Tokyo 160-8582, Japan. E-mail address: [email protected] (M. Kataoka).
http://dx.doi.org/10.1016/j.ijcard.2016.03.061 0167-5273/© 2016 Elsevier Ireland Ltd. All rights reserved.
2 weeks after the final session. Measurements of pulmonary function testing were conducted in accordance with the American Thoracic Society recommendations [6,7], using a Multi-Functional Spirometer HI-801 and CHESTAC-9800 (CHEST Inc. Tokyo, Japan). Each parameter was presented as a percentage of the predicted value based on Global Lung Initiative equations. In addition, dead space ventilation fraction, VD/VT, which reflects ventilation/perfusion inequality, was calculated according to Bohr's equation: VD/VT = (PaCO2 − PetCO2) / PaCO2. PetCO2 was measured with an end-tidal carbon dioxide monitor, TG-920P (NIHON KOHDEN, Tokyo, Japan). Since starting PetCO2 measurements in January 2014, we have tested 22 patients. Alveolar-arterial oxygen gradient was calculated according to the results of blood gas testing. Table 1 shows the baseline characteristics of enrolled 55 patients. All patients were treated with comprehensive therapy including anticoagulant therapy and home-oxygen therapy. Over 80% (45 out of 55) of patients had WHO functional class III or IV at baseline, suggesting that the majority of this study population had clinically moderate to severe CTEPH. The mean number of BPA sessions conducted per patient was 6.05 (range, 2 to 13 sessions). A total of 20 hemoptysis events were observed out of 333 BPA sessions, and none required mechanical ventilation. No treatment-related death occurred. Hemodynamic parameters and B-type natriuretic peptide improved significantly after BPA (Table 2). Importantly, 53 out of 55 enrolled patients achieved target mean pulmonary arterial pressure (PAP) below 25 mm Hg, and mean PAP of other 2 patients were 26 and 28 mm Hg after final session, suggesting BPA could give a great benefit to improve pulmonary hypertension. The results of pulmonary function testing are shown in Table 2. Fundamental parameters of pulmonary function testing such as vital capacity (VC), forced vital capacity (FVC), and forced expiratory volume in 1 s (FEV1) increased significantly after BPA (all P b 0.01). Regarding to spirometric parameters, V50 increased significantly after BPA (P b 0.01), but V25 and V50/V25 did not change significantly (P = 0.47 and P = 0.62, respectively). Furthermore, total lung capacity (TLC), functional residual capacity (FRC), and peak expiratory flow (PEF) were improved significantly after BPA (P b 0.01, P = 0.01, and P b 0.01, respectively). The 95% confidence intervals for changes between before and after BPA were 1.0–4.2 (% predicted value) for TLC, 0.7–5.9 (% predicted value) for FRC, and 1.7–11.0 (% predicted value) for PEF. On the other hand, residual volume, FEV1/FVC, and diffusing capacity for carbon monoxide did not change significantly (P = 0.63, P = 0.52, and P = 0.62, respectively).
M. Takei et al. / International Journal of Cardiology 212 (2016) 190–191 Table 1 Baseline characteristics in enrolled patients. Variable (n = 55) Female, n (%) Age, years WHO-FC; I/II/III/IV, n Height, cm Weight, kg BMI, kg/m2 Post PEA, n (%) Medications Endothelin receptor antagonist, n (%) Oral prostacyclin analogue, n (%) Phosphodiesterase 5 inhibitor, n (%)
39 (70.9%) 65 [54 to 76] 0/10/41/4 158.3 [151.5 to 164.8] 54 [45.8 to 67.4] 21.9 [19.2 to 25.3] 6 (10.9%) 24 (43.6%) 24 (43.6%) 37 (67.3%)
Values are expressed as median [25th to 75th percentiles] for continuous variables, and as number and percentage for categorical variables. WHO-FC, world health organization functional class; BMI, body mass index; and PEA, pulmonary endarterectomy.
TLC is positively affected by inspiratory muscle strength, and negatively regulated by lung and chest wall elastic contractile power, while FRC is positively affected by chest wall elastic extension power, and negatively regulated by lung elastic contractile power. Since chest wall and respiratory muscle power are probably unaffected by BPA, the elevations of both TLC and FRC in this study suggested improvements in lung compliance.
Table 2 Hemodynamics and respiratory functional changes with balloon pulmonary angioplasty (BPA). Variable (n = 55)
Before BPA
After BPA
P value
Hemodynamic indices WHO-FC; I/II/III/IV, n Mean PAP, mm Hg Cardiac index, L/min PVR, dyne·sec·cm−5 BNP, pg/ml
0/10/41/4 37 [31 to 47] 2.0 [1.8 to 2.4] 661 [439 to 1018] 70.0 [24.4 to 286.9]
32/23/0/0 20 [16 to 22] 2.2 [1.9 to 2.6] 288 [204 to 340] 24.8 [14.8 to 47.0]
b0.01⁎ b0.01⁎ 0.04⁎ b0.01⁎ b0.01⁎
Respiratory indices TLC, % predicted VC, % predicted FRC, % predicted RV, % predicted FVC, % predicted FEV1, % predicted PEF, % predicted FEV1/FVC, % predicted V50 V25 V50/V25 DLCO, % predicted VD/VT (n = 22)
88.0 [79.5 to 96.0] 92.8 [83.4 to 101.3] 88.5 [76.4 to 103.1] 86.4 [72.4 to 100.0] 96.6 [85.8 to 106.2] 84.9 [75.2 to 94.0] 92.3 [78.2 to 106.5] 87.3 [83.1 to 93.9] 1.59 [1.16 to 2.54] 0.34 [0.22 to 0.67] 4.61 [3.44 to 5.73] 45.0 [37.0 to 52.1] 0.33 [0.29 to 0.37]
90.0 [81.1 to 99.7] 96.2 [88.9 to 106.0] 90.3 [81.3 to 102.3] 88.7 [77.6 to 100.1] 99.0 [92.1 to 108.2] 90.8 [80.6 to 100.1] 99.5 [86.0 to 108.8] 90.5 [82.1 to 94.1] 1.85 [1.31 to 2.63] 0.39 [0.23 to 0.64] 4.59 [4.03 to 5.91] 45.1 [37.1 to 52.8] 0.28 [0.17 to 0.31]
b0.01⁎ b0.01⁎ 0.01⁎ 0.63 b0.01⁎ b0.01⁎ b0.01⁎ 0.52 b0.01⁎ 0.47 0.62 0.62 b0.01⁎
Blood gas testing PaCO2 PaO2 HCO− 3 Base excess SaO2 AaDO2
38.1 [34.2 to 41.3] 55.7 [51.5 to 66.1] 25.6 [23.8 to 27.9] 1.70 [−0.30 to 3.85] 90.8 [87.5 to 93.5] 45.8 [35.1 to 51.4]
40.7 [38.4 to 43.6] 70.3 [62.0 to 79.1] 27.3 [25.0 to 29.0] 3.05 [1.10 to 4.80] 95.4 [93.1 to 96.5] 28.2 [23.3 to 34.2]
b0.01⁎ b0.01⁎ b0.01⁎ b0.01⁎ b0.01⁎ b0.01⁎
191
Changes in TLC, VC, FRC, and FVC were significantly correlated with changes in pulmonary vascular resistance (PVR), respectively (Spearman's ρ = 0.42 for correlation between TLC and PVR, P b 0.01; Spearman's ρ = 0.52 for correlation between VC and PVR, P b 0.01; ρ = 0.34 for correlation between FRC and PVR, P = 0.01; Spearman's ρ = 0.44 for correlation between FVC and PVR, P b 0.01), suggesting an association between reperfusion of pulmonary arteries and respiratory function restoration. In addition, the marker for ventilation/perfusion inequality, VD/VT, improved significantly after BPA from a median of 0.33 before BPA to 0.28 after BPA (P b 0.01), indicating that the newly acquired ventilation spaces were efficiently perfused. Alveolar-arterial oxygen gradient also significantly improved after BPA (P b 0.01). Furthermore, the results of blood gas testing demonstrated the significant improvements of partial pressure of arterial oxygen and oxygen saturation. These findings suggest that BPA improved gas exchange efficiency in patients with CTEPH. There are study limitations in this study. Even though we showed the correlation between changes in PVR and changes in lung function such as TLC, the mechanisms by which pulmonary artery reperfusion with BPA restores lung function are unclear. Considering previous reports showing an association between lung parenchymal scaring and lung volume reduction in patients with CTEPH, it is possible that lung reperfusion may restore residual ischemic lung tissues [8]. A higher incidence of acute lung reperfusion injury after balloon angioplasty of branch pulmonary artery stenosis has been reported [9], and it would be desirable to consider the association between acute lung reperfusion injury after BPA and respiratory function. Furthermore, alveolar recruitment through increased production of surfactant proteins due to the increased lung perfusion possibly offers another explanation for the elevated lung capacity. However, further studies are needed to adequately elucidate more detailed mechanisms underlying the observed effects. In conclusion, BPA improved respiratory function and oxygenation as well as hemodynamics. The findings in this study suggest BPA can improve both gas exchange efficiency and mechanics of breathing, leading to favorable effects on respiratory function in patients with CTEPH. Disclosure statement The authors have no conflicts of interest to disclose.
Values are expressed as median [25th to 75th percentiles] for continuous variables. Respiratory indices are presented as a percentage of the predicted value, estimated with age, sex, and height. Changes in hemodynamics and respiratory parameters before and after BPA were analyzed with Wilcoxon's signed-rank test. mean PAP, mean pulmonary artery pressure; PVR, pulmonary vascular resistance; BNP, brain natriuretic peptide; TLC, total lung capacity; VC, vital capacity; FRC, functional residual capacity; RV, residual volume; FVC, forced vital capacity; FEV1, forced expiratory volume in 1 s; PEF, peak expiratory flow; DLCO, diffusing capacity for carbon monoxide; PaCO2, partial pressure of arterial carbon dioxide; PaO2, partial pressure of arterial oxygen; SaO2, oxygen saturation; AaDO2, alveolar-arterial oxygen gradient. ⁎ P b 0.05.
References [1] M. Kataoka, T. Inami, K. Hayashida, et al., Percutaneous transluminal pulmonary angioplasty for the treatment of chronic thromboembolic pulmonary hypertension, Circ Cardiovasc Interv 5 (2012) 756–762. [2] T. Inami, M. Kataoka, N. Shimura, et al., Pulmonary edema predictive scoring index (PEPSI), a new index to predict risk of reperfusion pulmonary edema and improvement of hemodynamics in percutaneous transluminal pulmonary angioplasty, JACC Cardiovasc Interv 6 (2013) 725–736. [3] T. Inami, M. Kataoka, N. Shimura, et al., Pressure-wire-guided percutaneous transluminal pulmonary angioplasty: a breakthrough in the catheter-interventional therapy for chronic thromboembolic pulmonary hypertension, JACC Cardiovasc Interv 7 (2014) 1297–1306. [4] T. Inami, M. Kataoka, M. Ando, K. Fukuda, H. Yoshino, T. Satoh, A new era of therapeutic strategies for chronic thromboembolic pulmonary hypertension by two different interventional therapies; pulmonary endarterectomy and percutaneous transluminal pulmonary angioplasty, PlosOne 9 (2014) e94587. [5] T. Tsugu, M. Murata, T. Kawakami, et al., Significance of echocardiographic assessment for right ventricular function after balloon pulmonary angioplasty in patients with chronic thromboembolic induced pulmonary hypertension, Am J Cardiol 115 (2015) 256–261. [6] Standardization of Spirometry, Update. American Thoracic Society, Am J Respir Crit Care Med 1995 (152) (1994) 1107–1136. [7] American Thoracic Society. Single-breath carbon monoxide diffusing capacity (transfer factor). Recommendations for a standard technique — 1995 update, Am J Respir Crit Care Med 152 (1995) 2185–2198. [8] T.A. Morris, W.R. Auger, M.Z. Ysrael, et al., Parenchymal scarring is associated with restrictive spirometric defects in patients with chronic thromboembolic pulmonary hypertension, Chest 110 (1996) 399–403. [9] S. Yacouby, M. Meador, E. Mossad, Lung reperfusion injury in patients after balloon angioplasty for pulmonary artery stenosis, J Cardiothorac Vasc Anesth 28 (2014) 502–505.