Aiko Ogawa

Refined Balloon Pulmonary Angioplasty for Inoperable Patients with Chronic Thromboembolic Pulmonary Hypertension

Background—Although balloon pulmonary angioplasty (BPA) for inoperable patients with chronic thromboembolic pulmonary hypertension was first reported over a decade ago, its clinical application has been restricted because of limited efficacy and complications. We have refined the procedure of BPA to maximize its clinical efficacy. Methods and Results—Sixty-eight consecutive patients with inoperable chronic thromboembolic pulmonary hypertension underwent BPA. We evaluated pulmonary artery diameters and determined the appropriate balloon size by using intravascular ultrasound. We performed BPA in a staged fashion over multiple, separate procedures to maximize efficacy and reduce the risk of reperfusion pulmonary injury. A total of 4 (2–8) sessions were performed in each patient, and the number of vessels dilated per session was 3 (1–14). The World Health Organization functional class improved from 3 to 2 (P<0.01), and mean pulmonary arterial pressure was decreased from 45.4±9.6 to 24.0±6.4 mm Hg (P<0.01). One patient died because of right heart failure 28 days after BPA. During follow-up for 2.2±1.4 years after the final BPA, another patient died of pneumonia, and the remaining 66 patients are alive. In 57 patients who underwent right heart catheterization at follow-up, improvement of mean pulmonary arterial pressure was maintained (24.0±5.8 mm Hg at 1.0±0.9 years). Forty-one patients (60%) developed reperfusion pulmonary injury after BPA, but mechanical ventilation was required in only 4 patients. Conclusions—Our refined BPA procedure improves clinical status and hemodynamics of inoperable patients with chronic thromboembolic pulmonary hypertension, with a low mortality. A refined BPA procedure could be considered as a therapeutic approach for patients with inoperable chronic thromboembolic pulmonary hypertension.

Prednisolone Inhibits Proliferation of Cultured Pulmonary Artery Smooth Muscle Cells of Patients With Idiopathic Pulmonary Arterial Hypertension

Background—Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. There is no therapy that specifically inhibits SMC proliferation. Recent studies reported that prednisolone (PSL) inhibits the postangioplasty proliferation of SMCs in atherosclerotic arteries. In this study, we tested the hypothesis that PSL has antiproliferative effects on pulmonary artery SMCs of patients with IPAH. Methods and Results—Pulmonary artery SMCs were harvested from the pulmonary arteries of 6 patients with IPAH who underwent lung transplantation. Control SMCs were obtained from 5 patients with bronchogenic carcinoma who underwent lung lobectomy. After incubation in the presence of platelet-derived growth factor (PDGF), PSL was added at different concentrations and cell proliferation was assessed by 3H-thymidine incorporation. PSL (2×10−4 and 2×10−3 mol/L) significantly inhibited PDGF-stimulated proliferation (P<0.05) of SMCs from patients with IPAH but did not affect cell viability of SMCs, as confirmed by trypan blue staining. In cell cycle analysis using a microscope-based multiparameter laser scanning cytometer, PSL inhibited the progression of SMCs from G0/G1 to the S phase. This inhibition was associated with increased p27 expression level. PSL (2×10−4 mol/L) also inhibited PDGF-induced SMC migration. Conclusions—Our results indicate that PSL has an antiproliferative effect on cultured SMCs of pulmonary arteries from patients with IPAH and suggest that PSL may be potentially useful therapeutically in patients with IPAH.

Pro-apoptotic effects of imatinib on PDGF-stimulated pulmonary artery smooth muscle cells from patients with idiopathic pulmonary arterial hypertension☆

BACKGROUND Remodeling of the pulmonary artery by an inappropriate increase of pulmonary artery smooth muscle cells (PASMCs) is problematic in the treatment of idiopathic pulmonary arterial hypertension (IPAH). Effective treatment that achieves reverse remodeling is required. The aim of this study was to assess the pro-apoptotic effects of imatinib, a platelet-derived growth factor (PDGF)-receptor tyrosine kinase inhibitor, on PASMCs obtained from patients with IPAH. METHODS PASMCs were obtained from 8 patients with IPAH undergoing lung transplantation. Cellular proliferation was assessed by (3)H-thymidine incorporation. Pro-apoptotic effects of imatinib were examined using TUNEL and caspase-3,7 assays and using transmission electron microscopy. RESULTS Treatment with imatinib (0.1 to 10 μg/mL) significantly inhibited PDGF-BB (10 ng/mL)-induced proliferation of PASMCs from IPAH patients. Imatinib (1 μg/mL) did not induce apoptosis in quiescent IPAH-PASMCs, but it had a pro-apoptotic effect on IPAH-PASMCs stimulated with PDGF-BB. Imatinib did not induce apoptosis in normal control PASMCs with or without PDGF-BB stimulation. PDGF-BB induced phosphorylation of Akt at 15 min, and Akt phosphorylation was inhibited by imatinib in IPAH-PASMCs. Akt-I-1/2 (1 μmol/L), an Akt inhibitor, in the presence of PDGF-BB significantly increased apoptotic cells compared with the control condition. Thus, Akt-I-1/2 could mimic the effects of imatinib on PASMCs. CONCLUSION Imatinib has anti-proliferative and pro-apoptotic effects on IPAH-PASMCs stimulated with PDGF. The inhibitory effect of imatinib on Akt phosphorylation induced by PDGF plays an important role in the pro-apoptotic effect.

Novel Angiographic Classification of Each Vascular Lesion in Chronic Thromboembolic Pulmonary Hypertension Based on Selective Angiogram and Results of Balloon Pulmonary Angioplasty

Background—Balloon pulmonary angioplasty (BPA) is an alternative therapy for patients with chronic thromboembolic pulmonary hypertension who are ineligible for standard therapy, pulmonary endarterectomy. Although there are several classifications of vascular lesions, these classifications are based on the features of the specimen removed during pulmonary endarterectomy. Because organized thrombi are not removed during balloon pulmonary angioplasty, we attempted to establish a new classification of vascular lesions based on pulmonary angiographic images. We evaluated the success and complication rate of BPA in accordance with the location and morphology of thromboembolic lesions. Methods and Results—We reviewed 500 consecutive procedures (1936 lesions) of BPA in 97 patients with chronic thromboembolic pulmonary hypertension and investigated the outcomes of BPA based on the lesion distribution and the angiographic characteristics of the thromboembolic lesions, as follows: type A, ring-like stenosis lesion; type B, web lesion; type C, subtotal lesion; type D, total occlusion lesion, and type E, tortuous lesion. The success rate was higher, and the complication rate was lower in ring-like stenosis and web lesions. The total occlusion lesions had the lowest success rate. Tortuous lesions were associated with a high complication rate and should be treated only by operators with extensive experience with BPA. Conclusions—We modified the previous angiographic classification and established a new classification for each vascular lesion. We clarified that the outcome and complication rate of the BPA are highly dependent on the lesion characteristics.

Balloon Pulmonary Angioplasty: A Treatment Option for Inoperable Patients with Chronic Thromboembolic Pulmonary Hypertension.

In chronic thromboembolic pulmonary hypertension (CTEPH), stenoses or obstructions of the pulmonary arteries due to organized thrombi can cause an elevation in pulmonary artery resistance, which in turn can result in pulmonary hypertension. CTEPH can be cured surgically by pulmonary endarterectomy (PEA); however, patients deemed unsuitable for PEA due to lesion, advanced age, or comorbidities have a poor prognosis and limited treatment options. Recently, advances have been made in balloon pulmonary angioplasty for these patients, and this review highlights this recent progress.

Inhibitory Effects of Simvastatin on Platelet-derived Growth Factor Signaling in Pulmonary Artery Smooth Muscle Cells From Patients With Idiopathic Pulmonary Arterial Hypertension

Idiopathic pulmonary arterial hypertension (IPAH) is a progressive disease characterized by inappropriate increase of pulmonary artery smooth muscle cells (PASMCs) leading to occlusion of pulmonary arterioles. Inhibition of platelet-derived growth factor (PDGF) signaling is starting to garner attention as a targeted therapy for IPAH. We assessed the inhibitory effects of simvastatin, a 3-hydroxy-3-methylglutanyl coenzyme A reductase inhibitor, on PDGF-induced proliferation and migration of PASMCs obtained from 6 patients with IPAH who underwent lung transplantation. PDGF stimulation caused a significantly higher growth rate of PASMCs from patients with IPAH than that of normal control PASMCs as assessed by 3H-thymidine incorporation. Simvastatin (0.1 μmol/L) significantly inhibited PDGF-induced cell proliferation of PASMCs from patients with IPAH but did not inhibit proliferation of normal control cells at the same concentration. Western blot analysis revealed that simvastatin significantly increased the expression of cell cycle inhibitor p27. PDGF significantly increased the migration distance of IPAH-PASMCs compared with that of normal PASMCs, and simvastatin (1 μmol/L) significantly inhibited PDGF-induced migration. Immunofluorescence staining revealed that simvastatin (1 μmol/L) inhibited translocation of Rho A from the cytoplasm to membrane and disorganized actin fibers in PASMCs from patients with IPAH. In conclusion, simvastatin had inhibitory effects on inappropriate PDGF signaling in PASMCs from patients with IPAH.

Carvedilol inhibits proliferation of cultured pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension.

Idiopathic pulmonary arterial hypertension (IPAH) is associated with proliferation of smooth muscle cells (SMCs) in small pulmonary arteries. Inhibition of proliferation of pulmonary artery smooth muscle cells (PASMCs) may be an effective treatment of patients with idiopathic pulmonary arterial hypertension. Recent studies have shown that carvedilol, an α- and β-blocker with antioxidant and calcium channel blocking properties, inhibits the proliferation of cultured normal human pulmonary artery smooth muscle cells. In this study, we tested the hypothesis that carvedilol has antiproliferative effects on pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension. Pulmonary artery smooth muscle cells from six idiopathic pulmonary arterial hypertension patients who had undergone lung transplantation were cultured. To determine cell proliferation, 3H-thymidine incorporation was measured. Platelet-derived growth factor-induced proliferation of IPAH-PASMCs was significantly greater than that of normal control pulmonary artery smooth muscle cells. Carvedilol (0.1 μM to 10 μM) inhibited the proliferation of idiopathic pulmonary arterial hypertension-pulmonary artery smooth muscle cells in a concentration-dependent manner. Prazosin (an α-blocker) and N-acetyl L cysteine (an antioxidant agent) (0.1 μM to 10 μM) did not inhibit their proliferation, but the high concentration of propranolol (a β-blocker) and nifedipine (a calcium channel blocker) (10 μM) inhibited the proliferation. The combination of propranolol and nifedipine inhibited the proliferation but only at a high concentration (10 μM) combination. Cell cycle analysis revealed that carvedilol (10 μM) significantly decreased the number of cells in S and G2/M phases. These results indicate that carvedilol inhibits the exaggerated proliferation of pulmonary artery smooth muscle cells of patients with idiopathic pulmonary arterial hypertension partially via its α-blocking and calcium channel blocking effects in vitro.

Long-term patient survival with idiopathic/heritable pulmonary arterial hypertension treated at a single center in Japan.

AIMS Idiopathic/heritable pulmonary arterial hypertension (I/HPAH) carries a poor prognosis despite the therapeutic options available. Patient survival from Western countries has been reported, but data from Asia are scarce. MAIN METHODS We retrospectively reviewed 56 patients with I/HPAH treated at a single referral center in Japan. Survival analyses were conducted using the Kaplan-Meier method with the log-rank test. Variables associated with survival were determined using a Cox proportional hazard model. KEY FINDINGS There were 41 women (73%) and the mean age at the diagnosis was 32±17 years. Mean survival time from the diagnosis was 14.9±0.8 years (95% CI, 13.4-16.4 years), with 1-, 2-, 3-, 5- and 10-year survival rates of 98, 96, 96, 96 and 78%, respectively. In patients who underwent follow-up right-heart catheterization >3 months after initial catheterization, mean pulmonary arterial pressure (mPAP) was decreased significantly from 63±15 to 35±10 mm Hg with an improved cardiac index. Patients with high levels of brain natriuretic peptide (BNP) or low oxygen saturation at baseline showed worse survival. At follow-up, 98% of patients were on PAH-targeted drugs. WHO functional classes I and II, mPAP <42.5 mm Hg, cardiac index >2.5 L/min/m(2), BNP <52 pg/mL, and 6-min walk distance >347 m at follow-up were predictors of good prognosis in the univariate analysis. SIGNIFICANCE The study revealed a long-term survival of Japanese patients with I/HPAH. Hemodynamic parameters improved significantly after treatment, which might be related to high prescription rates of PAH-targeted drugs. Multicenter studies are needed to reveal the prognostic factors for I/HPAH.

Three-Dimensional Structure of Pulmonary Capillary Vessels in Patients With Pulmonary Hypertension

Pulmonary arterial hypertension, pulmonary veno-occlusive disease, and pulmonary capillary hemangiomatosis are included in the same group (group 1) of clinical classification of pulmonary hypertension.1 Histological changes in the small pulmonary arteries (ie, intimal fibrosis and medial hypertrophy) are similar in these 3 diseases, and clinical presentations of the 3 diseases are often indistinguishable.1 However, it is estimated that the hemodynamics of capillary vessels are quite different in each disease. The hemodynamics of capillary vessels (ie, capillary occlusion) play an important role in cardiovascular diseases.2 Thus, clarification of the differences in the hemodynamics is essential to understand the pathophysiology of these 3 diseases. We obtained lung segments from patients with pulmonary hypertension who underwent living-donor lung transplantation and from patients with …

epoprostenol sodium for treatment of pulmonary arterial hypertension

The release of endogenous prostacyclin (PGI2) is depressed in patients with pulmonary arterial hypertension (PAH). PGI2 replacement therapy by epoprostenol infusion is one of the best treatments available for PAH. Here, we provide an overview of the current clinical data for epoprostenol. Epoprostenol treatment improves symptoms, exercise capacity, and hemodynamics, and is the only treatment that has been shown to reduce mortality in patients with idiopathic PAH (IPAH) in randomized clinical trials. We have reported that high-dose epoprostenol therapy (>40 ng/kg/min) also results in marked hemodynamic improvement in some patients with IPAH. High-dose epoprostenol has a pro-apoptotic effect on PAH-PASMCs via the IP receptor and upregulation of Fas ligand (FasL) in vitro. However, long-term intravenous administration of epoprostenol is sometimes associated with catheter-related infections and leads to considerable inconvenience for the patient. In the future, the development of new routes of administration or the development of powerful PGI2 analogs, IP-receptor agonists, and gene and cell-based therapy enhancing PGI2 production with new routes of administration is required.