Histological changes of pulmonary arteries treated by balloon pulmonary angioplasty in a patient with chronic thromboembolic pulmonary hypertension

Spontaneous hemodynamic improvement after balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension is observed within a short term after balloon pulmonary angioplasty

Natural hemodynamic changes after balloon pulmonary artery angioplasty (BPA) in a unified state without oxygen administration in patients with chronic thromboembolic pulmonary hypertension (CTEPH) remains undetermined. This study aimed to clarify the delayed changes in the hemodynamics after BPA in patients with CTEPH. We analyzed 73 consecutive patients with CTEPH who underwent BPA between July 2014 and December 2022. We extracted and evaluated hemodynamic data of the right heart catheter without oxygen administration immediately before and after the first BPA; and immediately before the second BPA, as the "post-delayed changes" after BPA. BPA significantly improved the mean pulmonary artery pressure (mPAP, mmHg) and pulmonary vascular resistance (PVR, dyn-s/cm5) from 36 (32-43) mmHg and 449 (312-627) dyn-s/cm5 before the first BPA to 28 (23-32) mmHg and 275 (217-366) dyn-s/cm5 immediately after BPA, and further significantly improved the values to 23 (20-28) mmHg and 225 (175-301) dyn-s/cm5 post-delayed changes after BPA, respectively. Improvement observed on account of delayed changes was observed both with and without pulmonary hypertension drugs. The delayed changes were observed during a period of 5-180 days, which did not correlate with the changes in mPAP and PVR. Hemodynamic improvement owing to BPA was observed immediately after BPA; however, further improvement was observed as a result of delayed changes. mPAP improved by 3.4 ± 5.2 mmHg and PVR by 53 (10-99) dyn-s/cm5 as delayed improvement. mPAP and PVR showed delayed improved by approximately 10% of their values before BPA.

Imaging of chronic thromboembolic pulmonary hypertension before, during and after balloon pulmonary angioplasty

Balloon pulmonary angioplasty (BPA) has recently been elevated as a class I recommendation for the treatment of inoperable or residual chronic thromboembolic pulmonary hypertension (CTEPH). Proper patient selection, procedural safety, and post-procedural evaluation are crucial in the management of these patients, with imaging work-up playing a pivotal role. Understanding the diagnostic and therapeutic imaging algorithms of CTEPH, the imaging features of patients amenable to BPA, all imaging findings observed during and immediately after the procedure and the changes observed during the follow-up is crucial for all interventional radiologists involved in the care of patients with CTEPH. This article illustrates the imaging work-up of patients with CTEPH amenable to BPA, the imaging findings observed before, during and after BPA, and provides a detailed description of all imaging modalities available for CTEPH evaluation.

Predictors of procedural complications in balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

BACKGROUND

Balloon pulmonary angioplasty (BPA) is an effective treatment for inoperable chronic thromboembolic pulmonary hypertension, with good results reported for residual pulmonary hypertension (PH) after pulmonary endarterectomy (PEA). However, BPA is associated with complications, such as pulmonary artery perforation and vascular injury, which can lead to critical pulmonary hemorrhage requiring embolization and mechanical ventilation. Furthermore, the risk factors for occurrence of complications in BPA are unclear; therefore, this study aimed to evaluate predictors of procedural complications in BPA.

METHODS

In this retrospective study, we collected clinical data (patient characteristics, details of medical therapy, hemodynamic parameters, and details of the BPA procedure) from 321 consecutive sessions involving 81 patients who underwent BPA. Procedural complications were evaluated as endpoints.

RESULTS

BPA for residual PH after PEA was performed in 141 sessions (43.9 %), which involved 37 patients. Procedural complications were observed in 79 sessions (24.6 %), including severe pulmonary hemorrhage requiring embolization in 29 sessions (9.0 % of all sessions). No patients experienced severe complications requiring intubation with mechanical ventilation or extracorporeal membrane oxygenation. Age ≥ 75 years and mean pulmonary artery pressure ≥ 30 mmHg were independent predictors of procedural complications. Residual PH after PEA was a significant predictor of severe pulmonary hemorrhage requiring embolization (adjusted odds ratio, 3.048; 95 % confidence interval, 1.042-8.914, p = 0.042).

CONCLUSIONS

Older age, high pulmonary artery pressure, and residual PH after PEA increase the risk of severe pulmonary hemorrhage requiring embolization in BPA.

Low incidence of restenosis after successful balloon pulmonary angioplasty in patients with chronic thromboembolic pulmonary hypertension

Balloon pulmonary angioplasty (BPA) is now a treatment option for patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH). However, the incidence of restenosis and long-term changes in vessel diameters in pulmonary arteries after BPA are unknown. The present study investigated the incidence of restenosis by measuring changes in vessel diameter after BPA. We reviewed 58 patients (168 lesions) with CTEPH who underwent single dilation for the target lesion (type A/B/C lesions) during BPA procedure followed by selective pulmonary angiography more than 6 months after the final BPA procedure. The outcomes of BPA were assessed in terms of pulmonary artery diameters. In a median follow-up of 1.9 (1.2-2.7) years, restenosis occurred in only one case with a type C lesion after BPA (0.6%). In type A/B lesions, the minimal lumen diameter was significantly enlarged at follow-up after BPA [3.48 (2.59-4.34) to 4.22 (3.31-4.90) mm]. In type C lesions, the minimal lumen diameter was unchanged at follow-up after BPA [3.15 (1.96-3.64) to 3.28 (2.38-4.61) mm]. The present results revealed that restenosis after BPA rarely occurs in type A/B/C lesions. Minimal lumen diameters for type A/B lesions continually increased and those for type C lesions did not decrease. Stent implantation in type A/B/C lesions would be unnecessary after BPA.

Treatment of Vascular Injury During Balloon Pulmonary Angioplasty in Patients With Chronic Thromboembolic Pulmonary Hypertension

Background

Treatment strategy for vascular injury during balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) was uncertain.

Objectives

This study aimed to identify an optimal therapeutic strategy for vascular injury during BPA in patients with CTEPH.

Methods

This study reviewed 207 patients with CTEPH and 956 BPA procedures between November 1, 2012 and November 30, 2015. Patients who were diagnosed with vascular injury during BPA, which was defined as angiographic signs or sudden respiratory and hemodynamic defects were included in this study. The study investigated the safety and efficacy of the hierarchically systematic treatment strategy including gelatin sponge embolization (GSE).

Results

More than one-half of the 79 patients and 133 procedures with vascular injury were improved by general treatment with reversal of heparin and high-flow oxygen administration. The investigators performed conventional treatment of proximal vessel occlusion using a guiding or balloon catheter in 47 procedures (35%) in which the culprit vessels could be detected under patients' stable conditions. In 32 procedures (24%) without detected culprit lesions or improvement by conventional treatment, GSE could significantly improve patient condition. The treatment strategy obtained successful bailout in 98% of procedures with vascular injury. No patients who underwent GSE died within 30 days after the treatment. There was no significant difference in cumulative mortality rate (median follow-up: 6.6 years) between groups with or without GSE (15.6% vs 8.2%; adjusted HR: 1.47; 95% CI: 0.25-8.69; P = 0.67).

Conclusions

Treatment strategy including GSE would be promising for vascular injury during BPA in patients with CTEPH.

Interventional Management of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension is a distinct form of pulmonary hypertension characterized by the nonresolution of thrombotic material in the pulmonary tree; whenever feasible and safe, first-line treatment should be pulmonary thromboendarterectomy. In patients who are not operative candidates, balloon pulmonary angioplasty (BPA) has emerged as an effective treatment modality that results in improvements in functional class, symptoms, hemodynamics, 6-minute walk distance, and right ventricular and pulmonary artery mechanics. Careful attention to procedural technique and rapid identification and treatment of complications are critical for a successful BPA program.

Continual Improvement in Pressure Gradient at the Lesion After Balloon Pulmonary Angioplasty for Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Lung injury is a serious complication of balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH). Selecting a smaller balloon might minimize the occurrence of lung injury; however, it could also increase the risk of restenosis.

METHODS

We analyzed the first target lesions in the initial BPA procedure in 34 consecutive patients with CTEPH. We measured proximal pressure with a guiding catheter and distal pressure with a pressure wire. We retrospectively investigated pressure gradients at the lesions before and immediately after the initial dilation with a smaller balloon and before the second procedure.

RESULTS

The proximal pressure decreased, and the distal pressure increased immediately after the initial balloon dilation. The pressure gradient at the lesion diminished significantly by the second procedure (from 26.4 ± 10.7 to 18.2 ± 9.9 mm Hg, P < 0.001) without serious complications. The residual pressure gradient had further diminished (to 9.8 ± 6.5 mm Hg, P = 0.02) until the second procedure. The reduction in pressure gradient at the lesion from immediately after the initial balloon dilation to the second procedure was positively correlated with both the baseline mean pulmonary arterial pressure (r² = 0.23, P = 0.004) and residual pressure gradient immediately after the initial balloon dilation (r² = 0.58, P < 0.001).

CONCLUSIONS

The residual pressure gradient at the lesion diminished continually after dilation with a smaller balloon. This strategy could decrease pulmonary arterial pressure safely. It would be reasonable to dilate the lesions sequentially in 2 procedures.

Pulmonary angioplasty: A step further in the continuously changing landscape of chronic thromboembolic pulmonary hypertension management

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potentially fatal and frequently undiagnosed form of pulmonary hypertension (PH), classified within group 4 by the World Health Organization (WHO). It is a type of precapillary PH, which uncommonly develops as a peculiar sequel of acute pulmonary embolism due to the partial resolution of the mechanically obstructing thrombus with a coexisting inflammatory response from pulmonary vessels. CTEPH is one of the potentially treatable forms of PH whose current standard of care is surgical pulmonary endarterectomy. Medical therapy with few drugs in non-operable disease is approved and has shown improvement in patients' hemodynamic condition and functional ability. Recently, balloon pulmonary angioplasty (BPA) has shown promising results as a treatment option for technically inoperable patients, those with unacceptable risk-to-benefit ratio and in a case of residual PH after endarterectomy. Lack of meticulous CTEPH screening programs in post-pulmonary embolism patients leading to underdiagnosis of this condition, complex operability assessment, and diversity in BPA techniques among different institutions are still the issues that need to be addressed. In this paper, we review the recent achievements in the management of non-operable CTEPH, their outcome and safety, based on available data.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: State of the art

Chronic thromboembolic pulmonary hypertension (CTEPH) is a complex chronic disease in which pulmonary artery stenosis or obstruction caused by organized thrombus can lead to increased pulmonary artery pressure and pulmonary vascular resistance, ultimately triggering progressive right heart failure and death. Currently, its exact mechanism is not fully understood. Pulmonary endarterectomy (PEA) has immediate effects with low perioperative mortality and satisfactory prognosis in experienced expert centers for CTEPH patients with proximal lesions. Nevertheless, 37% of patients are deemed unsuitable for PEA surgery due to comorbidities and other factors, and nearly half of the operated patients have residual or recurrent pulmonary hypertension. Riociguat is the only approved drug for CTEPH, although its effect is limited. Balloon pulmonary angioplasty (BPA) is a promising alternative treatment for patients with CTEPH. After more than 30 years of development and refinements, emerging evidence has confirmed its role in patients with inoperable CTEPH or residual/recurrent pulmonary hypertension, with acceptable complications and comparable long-term prognosis to PEA. This review summarizes the pathophysiology of CTEPH, BPA history and development, therapeutic principles, indications and contraindications, interventional procedures, imaging modalities, efficacy and prognosis, complications and management, bridging and hybrid therapies, ongoing clinical trials and future prospects.

Virtual Histology to Evaluate Mechanisms of Pulmonary Artery Lumen Enlargement in Response to Balloon Pulmonary Angioplasty in Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) results from an obstruction of pulmonary arteries (PAs) by organized thrombi. The stenosed PAs are targeted during balloon pulmonary angioplasty (BPA). We aimed to evaluate the mechanism of BPA in inoperable patients with CTEPH. We analyzed stenosed PAs with intravascular grey-scale ultrasound (IVUS) to determine the cross-sectional area (CSA) of arterial lumen and of organized thrombi. The composition of organized thrombi was assessed using virtual histology. We distinguished two mechanisms of BPA: Type A with dominant vessel stretching, and type B with dominant thrombus compression. PAs were assessed before (n = 159) and after (n = 98) BPA in 20 consecutive patients. Organized thrombi were composed of dark-green (57.1 (48.0–64.0)%), light-green (34.0 (21.4–46.4)%), red (6.4 (2.9–11.7)%;) and white (0.2 (0.0–0.9)%) components. The mechanism type depended on vessel diameter (OR = 1.09(1.01–1.17); p = 0.03). In type B mechanism, decrease in the amount of light-green component positively correlated with an increase in lumen area after BPA (r = 0.50; p = 0.001). The mechanism of BPA depends on the diameter of the vessel. Dilation of more proximal PAs depends mainly on stretching of the vessel wall while dilation of smaller PAs depends on compression of the organized thrombi. The composition of the organized thrombi contributes to the effect of BPA.

Pulmonary thromboembolism with computed tomography defined chronic thrombus is associated with higher mortality

With the advancement of computed tomography pulmonary angiography, differentiating between acute and chronic thrombus in pulmonary embolism has become more feasible. However, whether pulmonary embolism with chronic thrombus contributes to a higher mortality than pulmonary embolism with acute thrombus remains undetermined. Additionally, the clinical features of patients with chronic thrombus are largely unknown. Herein, we aimed to investigate the incidence and outcomes of patients with pulmonary embolism and chronic thrombus. This retrospective study included patients with pulmonary embolism from 2008 to 2016 at National Cheng Kung University Hospital. After excluding patients with tumor emboli or other etiologies and a lack of computed tomography images, we identified 205 patients with acute thrombus and 58 patients with chronic thrombus. Patients with chronic thrombus initially presented mainly with dyspnea, and the etiology was not related to recent surgery. Patients with chronic thrombus had a significantly higher incidence of elevated right ventricular systolic pressure detected by echocardiography and a higher incidence of subsequent events due to residual pulmonary embolism. Despite no differences in clinically recurrent pulmonary embolism, patients with chronic thrombus presented with a higher risk of all-cause and pulmonary embolism-related mortality than patients with acute thrombus. Chronic thrombus (hazard ratio: 2.03, p = 0.03), simplified pulmonary embolism severity index, anticoagulant use, and body mass index were the independent factors for all-cause mortality. Our findings suggest that using computed tomography pulmonary angiography for identifying patients with pulmonary embolism and chronic thrombus, which was associated with a higher risk of mortality, is pivotal for early intervention in addition to anticoagulant use.

Vascular Injury Is a Major Cause of Lung Injury After Balloon Pulmonary Angioplasty in Patients With Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Balloon pulmonary angioplasty (BPA) has become an alternative treatment for inoperable patients with chronic thromboembolic pulmonary hypertension. Lung injury (LI) is a major complication of BPA and may attenuate the benefits of BPA. Therefore, we conducted a retrospective study to evaluate the association between patient and procedural characteristics and LI in patients with chronic thromboembolic pulmonary hypertension.

METHODS AND RESULTS

We reviewed 76 patients with chronic thromboembolic pulmonary hypertension who underwent BPA and multidetector computed tomography scanning pre- and post-BPA procedures. We performed BPA on 1247 vessels during 297 BPA procedures and reviewed 594 multidetector computed tomography scans. By comparing pre- and post-BPA multidetector computed tomography images, we diagnosed LI as follows: newly appeared ground-glass opacity, consolidation, and pleural effusion. LI was detected using multidetector computed tomography scans during 138 procedures (47%), and mechanical ventilation was required during 40 procedures (13%). Angiographic findings of extravasation with or without simultaneous clinical symptoms (BPA-related vascular injury) occurred during 50 procedures (17%). In mixed-effect logistic regression models, the BPA-related vascular injury was an independent predictor of LI after BPA, odds ratio, 20.1 (6.43-63.1). High mean pulmonary artery pressure before BPA procedure and BPA-related vascular injury were independent predictors of mechanical ventilation after BPA, odds ratio, 1.13 (1.03-1.24) and 10.8 (3.77-30.9), respectively.

CONCLUSIONS

Vascular injury during BPA could be a triggering factor of LI after BPA, and its severity could be exacerbated by a high pulmonary artery pressure.

Vessel Stretching Is a Cause of Lumen Enlargement Immediately After Balloon Pulmonary Angioplasty: Intravascular Ultrasound Analysis in Patients With Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

Balloon pulmonary angioplasty (BPA) has become an alternative therapy for patients with chronic thromboembolic pulmonary hypertension who are ineligible for pulmonary endarterectomy. We retrospectively investigated intravascular ultrasound measurements to elucidate how the lumen enlarges immediately after BPA.

METHODS AND RESULTS

A total of 326 lesions in 71 patients with chronic thromboembolic pulmonary hypertension were analyzed. The cross-sectional areas (CSAs) of the external elastic membrane and lumen measured by intravascular ultrasound before and after BPA were assessed for each lesion type (type A, ring-like stenosis lesions; type B, web lesions; type C, subtotal occlusion lesions). Comparing the lesion types, the proportion of the area occupied by fibrous tissue was smallest in the type A lesions and largest in the type C lesions. The mean lesion lumen CSA was increased after BPA because of an increase in external elastic membrane CSA (from 23.2±12.9 to 27.2±14.3 mm²; P<0.001) with a slight decrease in fibrous tissue plus media CSA (from 17.7±11.7 to 17.3±11.1 mm²; P<0.001). The change in lumen CSA correlated strongly with the change in external elastic membrane CSA (r²=0.762; P<0.001).

CONCLUSIONS

Lumen enlargement immediately after BPA was obtained by the overall vessel expansion induced by a stretch of the arterial wall. In addition, the amount of fibrous tissue depended on each lesion type. Thus, it might be beneficial to change the balloon size to correspond with the lesion type.

Pulmonary Artery Elastic Properties After Balloon Pulmonary Angioplasty in Patients With Inoperable Chronic Thromboembolic Pulmonary Hypertension

BACKGROUND

A significant proportion of the right ventricular afterload is determined by the elastic properties of the pulmonary artery (PA). We aimed to assess the effect of balloon pulmonary angioplasty (BPA) on PA elastic properties in patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH).

METHODS

We enrolled adult patients with CTEPH treated with BPA and controls without PH. Total PA compliance (CPa) was calculated as stroke volume/PA pulse pressure. PA distensibility (DC) and compliance (CC) coefficients were assessed by intravascular ultrasound to denote local elastic properties of the treated PA segments.

RESULTS

We performed 103 BPA sessions in 17 patients with CTEPH (5 men [29%], aged 66 [64 to 73] years) who were followed for 6 (5 to 7) months after the last BPA. The median time between BPA sessions was 39 (28 to 52) days. The CPa, CC, and DC were lower in patients with CTEPH than in controls without PH (n = 10). Complete BPA treatment led to increase of CPa from 1.02 (0.70 to 1.39) to 2.08 (1.49 to 2.39) mL/mm Hg (P < 0.001) at the 6-month follow up, and this increase was in proportion to a decrease in pulmonary vascular resistance (PVR) (R² = 0.74; P = 0.001). CPa increased immediately after BPA session by 0.13 (-0.05; 0.33) mL/mm Hg (P = 0.001) and remained unchanged until the next BPA session. CC and DC exhibited no immediate change after catheter balloon inflation (Δ=0 [-0.03; 0.02] mm²/mm Hg, P = 0.52, and Δ = 0 [-0.13; 0.13] %/mm Hg, P = 0.91, respectively) and remained unchanged at the 6-month follow-up.

CONCLUSIONS

BPA improved total CPa in proportion to a decrease in PVR despite no improvement in local elastic properties of the treated PA segments.

Shortening Hospital Stay Is Feasible and Safe in Patients With Chronic Thromboembolic Pulmonary Hypertension Treated With Balloon Pulmonary Angioplasty

BACKGROUND

There is no consensus on the length of hospital stay (LOHS) and post-interventional management after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We examined temporal trends with respect to LOHS and requirement for intensive care for BPA and their relationship with the incidence of BPA-related complications.

METHODS

From November 2012 to September 2017, a total of 123 consecutive patients with CTEPH who underwent BPA were enrolled (age: 66.0 [54.0 to 74.0], World Health Organization [WHO] functional class II/III/IV; 27/88/8). Patients were divided for analysis into 3 groups according to the date of their first BPA: early-, middle-, and late-phase groups.

RESULTS

Mean pulmonary arterial pressure decreased from 36.0 (29.0 to 45.0) to 20.0 (16.0 to 22.0) mm Hg after BPA (P < 0.001). The LOHS was 41.0 (31.0 to 54.0) days in total including all sessions and 6.6 (6.0 to 7.9) days/session. Despite no significant differences in age, baseline hemodynamics, and laboratory data among the 3 groups, there was a significant reduction in LOHS (7.9 [7.0 to 9.5], 6.5 [6.1 to 7.3], 6.0 [5.3 to 6.5] days/session, P < 0.001) and use of intensive/high care unit (100%, 93%, 46%, P < 0.001). The reduction in LOHS and intensive/high care unit use did not affect the occurrence of BPA-related complications.

CONCLUSIONS

Increasing experience with BPA was associated with a reduction in LOHS and the use of intensive/high care unit, but no change was noted in the rate of BPA-related complications. These findings suggest that the reduction in both LOHS and use of the intensive care unit for BPA is feasible and does not jeopardize the safety of the procedure.

After the Dawn - Balloon Pulmonary Angioplasty for Patients With Chronic Thromboembolic Pulmonary Hypertension

In the past 5 years, balloon pulmonary angioplasty (BPA) for patients with chronic thromboembolic pulmonary hypertension (CTEPH) who are deemed inoperable has undergone significant refinement. As a result, the procedure is now used worldwide and has become a promising therapeutic option for those patients. However, pulmonary endarterectomy remains the gold standard treatment for patients with CTEPH because the techniques and strategies for BPA are not yet unified. The best therapeutic option for each patient should be determined based on discussion among a multidisciplinary team of experts. For BPA to become an established treatment for CTEPH, further data are needed. This review summarizes the techniques and strategies of BPA at present and discusses the future development of the procedure.

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 for Chronic Thromboembolic Pulmonary Hypertension

Background—

Balloon pulmonary angioplasty (BPA) is an alternative therapy for patients with chronic thromboembolic pulmonary hypertension who are ineligible for pulmonary endarterectomy—the standard therapy. Currently, most reported results of BPA are from relatively small cohorts treated at single centers. The present study evaluated the safety and efficacy of BPA for chronic thromboembolic pulmonary hypertension based on a multicenter registry.

Methods and Results—

A total of 308 patients (62 men and 246 women; mean age, 61 years) underwent 1408 procedures at 7 institutions in Japan. Data were retrospectively reviewed to evaluate clinical outcome and complications. Hemodynamics were significantly improved in 249 patients in whom BPA was terminated, most often because of improvement in mean pulmonary arterial pressure or symptomatic improvement after 1154 procedures. In 196 patients who underwent follow-up right heart catheterization, improvement of hemodynamic parameters was maintained. Mean pulmonary arterial pressure decreased from 43.2±11.0 to 24.3±6.4 mm Hg after final BPA and 22.5±5.4 mm Hg at follow-up, with significant reduction of concomitant use of pulmonary hypertension-targeted therapy and oxygen supplementation. Complications occurred in 511 (36.3%), including pulmonary injury (17.8%), hemoptysis (14.0%), and pulmonary artery perforation (2.9%). Twelve patients (3.9%) died during follow-up, including 8 patients who died within 30 days after BPA. The leading causes of death were right heart failure, multiorgan failure, and sepsis. Overall survival was 96.8% (95% confidence interval, 93.7%–98.4%) at 1 and 2 years and 94.5% (95% confidence interval, 89.3%–97.3%) at 3 years, respectively, after the initial BPA procedure for all 308 patients.

Conclusions—

This multicenter registry suggested improved hemodynamic results after BPA. Complication rates were high, but overall survival was comparable with pulmonary endarterectomy. BPA may be an important therapeutic option in patients with chronic thromboembolic pulmonary hypertension.

Treatment of Chronic Thromboembolic Pulmonary Hypertension: The Role of Medical Therapy and Balloon Pulmonary Angioplasty

Chronic thromboembolic pulmonary hypertension (CTEPH) is a potentially curable disease when treated with pulmonary thromboendarterectomy (PTE). However, even at experienced surgical centers, nearly one-third of patients with CTEPH will be deemed inoperable for reasons including distal disease, comorbidities, or out-of-proportion pulmonary hypertension. It is in these patients with inoperable CTEPH that pulmonary hypertension (PH)-targeted medical therapy and balloon pulmonary angioplasty have potential therapeutic value. Previous unblinded cohort trials have assessed PH-targeted medical therapy in various subpopulations of CTEPH patients using epoprostenol, treprostinil, sildenafil, bosentan, and iloprost, each demonstrating measurable pulmonary hemodynamic effects. However, riociguat, a soluble guanylate cyclase stimulator, is the first FDA-approved therapy for inoperable CTEPH to demonstrate both an improvement in functional capabilities (6-minute walk time) as well as significant gains in secondary pulmonary hemodynamic end points in a large placebo-controlled trial. Balloon pulmonary angioplasty is an interventional procedure using telescoping catheters placed in the pulmonary arteries, through which wires and balloons are used to mechanically disrupt chronic clot material and relieve pulmonary vascular obstruction. Contemporary case series from multiple centers worldwide have demonstrated pulmonary hemodynamic improvement with this approach. As a result of these advances, patients with inoperable CTEPH who had few options as recently as 5 years ago now have alternatives with emerging evidence of therapeutic efficacy.

The anticoagulant effects of warfarin and the bleeding risk associated with its use in patients with chronic thromboembolic pulmonary hypertension at a specialist center in Japan: a retrospective cohort study

Patients with chronic thromboembolic pulmonary hypertension (CTEPH) require lifelong anticoagulation therapy. However, the bleeding risk and recurrence of venous thromboembolism (VTE) in CTEPH patients who are administered warfarin have not been adequately evaluated. The purpose of this study was to evaluate the risk of clinically relevant bleeding, recurrent VTE, and clinical worsening in patients with CTEPH who were administered warfarin.

The clinical records of 72 patients with CTEPH who regularly visited our institution and were administered warfarin were retrospectively reviewed between 1 January 2011 and 31 December 2015. We investigated the incidence of clinically relevant bleeding events, recurrent VTE, and hospitalization for the deterioration of pulmonary hypertension or right heart failure (RHF) during the observation period.

The mean observation period for the 72 patients was 3.60 ± 1.60 person-years. Clinically relevant bleeding, RHF, and recurrent VTE occurred in 21 (29.2%), eight (11.1%), and three (4.2%) of 72 patients, respectively, and the incidence rates for these events were 8.1%/person-year, 3.1%/person-year, and 1.2%/person-year, respectively. The incidence rates for the major and non-major bleeding events were 5.0%/person-year and 3.9%/person-year, respectively. The incidence of clinically relevant bleeding events was 20.8%/person-year during medical treatment with a soluble guanylate cyclase stimulator. One of 35 patients (2.9%) during the post-pulmonary endarterectomy period experienced hemoptysis during observation period (> 6 months after pulmonary endarterectomy). No bleeding events occurred during the post-balloon pulmonary angioplasty period.

In conclusion, warfarin effectively prevents VTE recurrence in CTEPH patients, but its effects may be associated with a considerable bleeding risk.

Effects of Balloon Pulmonary Angioplasty on Oxygenation in Patients With Chronic Thromboembolic Pulmonary Hypertension - Importance of Intrapulmonary Shunt

BACKGROUND

Although balloon pulmonary angioplasty (BPA) improves the hemodynamics and prognosis of patients with inoperable chronic thromboembolic pulmonary hypertension (CTEPH), the mechanisms of improvement in oxygenation remain to be elucidated.

METHODS AND RESULTS

From August 2013 to May 2015, we performed a total of 113 BPA procedures in 24 patients with inoperable CTEPH (mean 4.7 procedures per patient). Median age was 70 [60, 74] years and 18 were female (75%). We examined hemodynamics, respiratory functions, and intrapulmonary shunt before and after the BPA procedure. Mean pulmonary arterial pressure (37 [28, 45] to 23[19, 27] mmHg, P<0.01), pulmonary vascular resistance (517 [389, 696] to 268 [239, 345] dyne/s/cm(5)) and 6-min walk distance (390 [286, 484] to 490 [411, 617] m, P<0.01) were significantly improved after BPA therapy. Furthermore, arterial oxygen partial pressure (PaO2, 54.8 [50.0, 60.8] to 65.2 [60.6, 73.2] %, P<0.01) and intrapulmonary shunt (23.4±6.0% to 19.3±5.0%, P<0.01) were also significantly ameliorated. In the multivariate analysis, decrease in intrapulmonary shunt after BPA was significantly correlated with improvement of both PaO2(r(2)=0.26, P<0.01) and SaO2(r(2)=0.49, P<0.01) after BPA.

CONCLUSIONS

These results indicated that BPA improved not only pulmonary hemodynamics but also oxygenation with a resultant decrease in intrapulmonary shunt. (Circ J 2016; 80: 2227-2234).

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.