Vessel Stretching Is a Cause of Lumen Enlargement Immediately After Balloon Pulmonary Angioplasty: Intravascular Ultrasound Analysis in Patients 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.

Effects of medical therapy and age on cardiac output changes following balloon pulmonary angioplasty: Implications for combination therapy in chronic thromboembolic pulmonary hypertension

BACKGROUND

Some patients with chronic thromboembolic pulmonary hypertension (CTEPH) exhibit exercise intolerance due to reduced cardiac output (CO) even after successful balloon pulmonary angioplasty (BPA). Medical therapy is a potential option for such cases; however, it is unclear which patients necessitate it even after BPA.

METHODS

This study included 286 patients with CTEPH who underwent BPA and right heart catheterization 1 year after the final BPA and classified them into no-medication and withdrawal groups. The no-medication group comprised patients without pulmonary hypertension (PH) medications before and after BPA, while the withdrawal group included patients who received PH medications before BPA and discontinued them after BPA. We assessed differences in the changes in CO after BPA from baseline (ΔCO) between the 2 groups. Additionally, we evaluated the ΔCO among different age categories within each group: younger (<60 years), middle-aged (60-70 years), and older adults (≥70 years).

RESULTS

After adjusting baseline covariates, overall CO did not differ significantly. However, ΔCO was significantly positive in the no-medication group but negative in the withdrawal group (0.32 and -0.33, difference in ΔCO: -0.65, 95% confidence intervals: -0.90 to -0.40). A significantly positive effect on ΔCO was observed in younger and middle-aged individuals, with a significant interaction between age and ΔCO in no-medication groups.

CONCLUSIONS

Increasing CO with BPA alone may be challenging with age in patients with CTEPH. Given that discontinuation of PH medication after BPA decreased CO more than the effect of BPA, medical therapy might be necessary even after successful BPA.

Flow Grade-Based Success Rates, Complication Rates, and Balloon Pulmonary Angioplasty Patency for Total Occlusions

BACKGROUND

The number of successfully recanalized total occlusions affects hemodynamic improvement after balloon pulmonary angioplasty (BPA) in patients with chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to clarify the current efficacy, patency, and success rate of BPA for total occlusions.

METHODS

Between April 2016 and August 2021, 178 BPAs were performed in 100 patients with CTEPH and total occlusions. The primary success and subsequent patency rates immediately before the second BPA procedure (follow-up) were compared between the segmental and subsegmental groups, based on the flow grade, which was defined as follows: 0, no reperfusion; 1, minimal reperfusion; 2, partial reperfusion; and 3, complete reperfusion.

RESULTS

Total occlusions were mainly located in the right lung (70%) and lower lobes (48%). The primary success rate was 88%, with significant improvements in oxygenation, hemodynamic parameters, and 6-minute walk test. The primary flow grade did not differ between groups. However, the proportion of lesions with a flow grade of 2 or 3 at follow-up was significantly higher in the subsegmental group than in the segmental group (84% vs 45%, respectively; P < 0.01). In multivariate analysis, flow grade in the acute phase (odds ratio [OR], 46.9; 95% confidence interval [CI], 12.54-176.78; P < 0.01) and subsegmental lesions (OR, 13.8; 95% CI, 3.24-58.94; P < 0.01) were independently associated with better patency (flow grade of 2 or 3) at follow-up.

CONCLUSIONS

Total occlusions can be safely and effectively treated with BPA. BPA for total occlusions may be preferable for subsegmental over segmental lesions.

[Chronic thromboembolic pulmonary hypertension]

Chronic thromboembolic pulmonary disease (CTEPD) is an important late complication of acute pulmonary embolism, in which the thrombi transform into fibrous tissue, become integrated into the vessel wall, and lead to chronic obstructions. CTEPD is differentiated into cases without pulmonary hypertension (PH), characterized by a mean pulmonary arterial pressure up to 20 mmHg and a form with PH. Then, it is still referred to as chronic thromboembolic pulmonary hypertension (CTEPH).When there is suspicion of CTEPH, initial diagnostic tests should include echocardiography and ventilation/perfusion scan to detect perfusion defects. Subsequently, referral to a CTEPH center is recommended, where further imaging diagnostics and right heart catheterization are performed to determine the appropriate treatment.Currently, three treatment modalities are available. The treatment of choice is pulmonary endarterectomy (PEA). For non-operable patients or patients with residual PH after PEA, PH-targeted medical therapy, and the interventional procedure of balloon pulmonary angioplasty (BPA) are available. Increasingly, PEA, BPA, and pharmacological therapy are combined in multimodal concepts.Patients require post-treatment follow-up, preferably at (CTE)PH centers. These centers are required to perform a minimum number of PEA surgeries (50/year) and BPA interventions (100/year).

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: a clinical consensus statement of the ESC working group on pulmonary circulation and right ventricular function

The current treatment algorithm for chronic thromboembolic pulmonary hypertension (CTEPH) as depicted in the 2022 European Society of Cardiology (ESC)/European Respiratory Society (ERS) guidelines on the diagnosis and treatment of pulmonary hypertension (PH) includes a multimodal approach of combinations of pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA) and medical therapies to target major vessel pulmonary vascular lesions, and microvasculopathy. Today, BPA of >1700 patients has been reported in the literature from centers in Asia, the US, and also Europe; many more patients have been treated outside literature reports. As BPA becomes part of routine care of patients with CTEPH, benchmarks for safe and effective care delivery become increasingly important. In light of this development, the ESC Working Group on Pulmonary Circulation and Right Ventricular Function has decided to publish a document that helps standardize BPA to meet the need of uniformity in patient selection, procedural planning, technical approach, materials and devices, treatment goals, complications including their management, and patient follow-up, thus complementing the guidelines. Delphi methodology was utilized for statements that were not evidence based. First, an anatomical nomenclature and a description of vascular lesions are provided. Second, treatment goals and definitions of complete BPA are outlined. Third, definitions of complications are presented which may be the basis for a standardized reporting in studies involving BPA. The document is intended to serve as a companion to the official ESC/ERS guidelines.

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.

Comparison of the safety and efficacy of balloon pulmonary angioplasty in chronic thromboembolic pulmonary hypertension patients with surgically accessible and inaccessible lesions

BACKGROUND

Although pulmonary endarterectomy is the treatment of choice for chronic thromboembolic pulmonary hypertension, not all patients are eligible. While balloon pulmonary angioplasty is an alternative for such patients, its efficacy and safety may differ between patients with and without surgically accessible lesions.

METHODS

This study involved 344 patients treated with balloon pulmonary angioplasty who were ineligible for pulmonary endarterectomy. Based on the angiographical lesion location, patients were divided into the surgically accessible (Group 1) and inaccessible (Group 2) groups, and percent changes in hemodynamics and clinical parameters before and after balloon pulmonary angioplasty were investigated. We also conducted survival analyses using Kaplan-Meier analysis.

RESULTS

While no differences in baseline characteristics were identified between the groups, balloon pulmonary angioplasty significantly improved hemodynamics in both groups, without any difference regarding the incidence of complications. Meanwhile, the percent changes in the mean pulmonary arterial pressure, pulmonary vascular resistance, 6-min walk distance, right ventricular area index on echocardiography, and the achievement rate of World Health Organization functional class I after balloon pulmonary angioplasty were significantly lower in Group 1 than in Group 2. The cumulative survival rates at 1, 5, and 10 years after balloon pulmonary angioplasty were not significantly different between the two groups (Group 1: 92.5%, 86.1%, 84.3%; and Group 2: 96.5%, 92.9%, 90.1%, respectively).

CONCLUSIONS

The outcome of balloon pulmonary angioplasty in inoperable patients with surgically accessible proximal lesions was acceptable; however, further investigations are necessary to clarify the optimal treatment for such patients.

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.

Circulatory disturbance of the cochlear spiral modiolar artery in a type 2 diabetic mouse model

Objective

This study aimed to identify significant differences in cochlea microvessel size between a diabetic mouse model (db/db) and normal mice using three‐dimensional (3D) quantitative analysis.

Methods

Six control heterozygote db/+ as well as 18 male B6/BKS(D)‐Lepr^db/J (db/db) mice aged 14 (n = 9) and 28 (n = 9) weeks were examined. After clearing the cochlea, we reconstructed the 3D volumes of the spiral modiolar artery (SMA) in the cochlea using light‐sheet microscopy and analyzed vessel wall thickness, cross‐sectional area, short and long diameter, and vessel height.

Results

The average SMA‐wall thickness in the db/db‐mouse group (3.418 ± 0.328 μm) was greater than that in the control group (2.388 ± 0.411 μm). The average cross‐sectional outer area, short diameter, and long diameter of the SMA in db/db mice were significantly larger than those in control mice (all p < 0.001). The cross‐sectional areas increased with age (control: 221.782 ± 121.230 μm, 14 weeks; 294.378 ± 151.008 μm, and 28 weeks; 312.925 ± 147.943 μm).

Conclusion

The db/db mice had thicker and larger proximal‐SMA vessel walls and diameters than control mice, respectively, thus potentially inducing increased blood viscosity or vascular insufficiency and aggravating hearing loss in type 2 diabetes mellitus.

Level of Evidence

IIb

Update on balloon pulmonary angioplasty for treatment of chronic thromboembolic pulmonary hypertension

PURPOSE OF REVIEW

To provide an update on balloon pulmonary angioplasty (BPA) for the treatment of chronic thromboembolic pulmonary hypertension (CTEPH), a pulmonary vascular disease that is characterized by fibro-thrombotic material mechanically obliterating major pulmonary arteries, resulting in increased pulmonary vascular resistance (PVR), progressive pulmonary hypertension (PH) combined with a microscopic pulmonary vasculopathy [1▪▪], right ventricular (RV) failure [2] and premature death.

RECENT FINDINGS

Data from a most recent CTEPH European registry (2015 and 2016) suggest significantly improved survival [3▪] of CTEPH patients compared with survival in the eighties [4], or with data from 2007 and 2009 [5]. Pulmonary endarterectomy (PEA) is still the gold-standard therapy for CTEPH [6,7]. However, only around two thirds of all CTEPH patients are amenable to surgery [3▪,5]. Patients not suitable for PEA and treated conservatively have a poor prognosis [8]. BPA may have a role for this particular group of patients. [9-11]. Currently, BPA programs are available in many countries, with excellent results at expert centers [12-15,16▪,17,18▪▪]. Based on recent data, BPA seems to have a greater impact on symptomatic and hemodynamic improvement than medical therapy with riociguat alone [15].

SUMMARY

The evidence favoring BPA is growing, but there is still a lack of published controlled trials. In addition, treatment concepts including indication, technical performance, use of PH-targeted medication, and the concept of follow-up vary between centers. In addition, there is a significant learning curve impacting outcomes [13]. The data from the International BPA registry will provide answers for some of the open questions.

Changes in Inflammatory Markers in Patients with Chronic Thromboembolic Pulmonary Hypertension Treated with Balloon Pulmonary Angioplasty

Background: Inflammatory response and endothelial dysfunction contribute to the progression of chronic thromboembolic pulmonary hypertension (CTEPH). We aimed to assess changes in biomarkers involved in those processes in inoperable CTEPH patients treated with balloon pulmonary angioplasty (BPA). Methods: We enrolled 20 patients with inoperable CTEPH qualified for BPA and a control group. Interleukin 6, 8, 10 (IL-6, IL-8, IL-10), monocyte chemoattractant protein-1 (MCP-1), and C-reactive protein (hsCRP) constituted the markers of systemic inflammation. Endothelin 1 (ET-1) served as a marker of endothelial dysfunction. Selected markers were assessed before the BPA treatment, 24 h after the first BPA, and six months after completion of the BPA treatment. Results: At baseline, the CTEPH patients had increased serum concentrations of IL-6, IL-8 and ET-1. Twenty-four hours after a BPA session, we observed an increase in concentrations of IL-6 (∆ = 3.67 (1.41; 7.16); p < 0.001), of IL-10 (∆ = 0.25 (0; 0.47); p = 0.003), of MCP-1 (∆ = 111 (60.1; 202.8); p = 0.002), and of hsCRP (∆ = 4.81 (3.46; 8.47); p < 0.001). Six months after completion of the BPA treatment, there was a decrease in concentrations of IL-6 (∆ = −1.61 (−3.11; −0.20); p = 0.03), of IL8 (∆ = −3.24 (−7.72; 0.82); p = 0.01), and of ET-1 (∆ = −0.47 (−0.96; 0.05); p = 0.005). Conclusions: Patients with inoperable CTEPH exhibit increased systemic inflammation and endothelial dysfunction, which improves after completion of the BPA treatment. A single BPA session evokes an acute inflammatory response.

The effectiveness of scoring balloon angioplasty in the treatment of chronic thromboembolic pulmonary hypertension

Background

Balloon pulmonary angioplasty (BPA) is an effective treatment for inoperable chronic thromboembolic pulmonary hypertension (CTEPH). The purpose of this study is to evaluate the therapeutic effect and safety of the non-slip element percutaneous transluminal angioplasty (NSE PTA) scoring balloons in BPA.

Methods

108 pulmonary artery branches in 14 CTEPH patients who underwent BPA using NSE PTA scoring balloon (the NSE PTA group) or plain balloon (the POBA group) and pressure gradient evaluation were analyzed. We compared the improvement of the pressure ratios after BPA (Δ Pressure ratio) of both groups.

Results

There was no significant difference in the Δ Pressure ratios of the two groups (0.241 ± 0.196 POBA, 0.259 ± 0.177 NSE PTA, p = 0.63). No complications occurred in the NSE PTA group, while 3 episodes of hemoptysis were seen in the POBA group. This, however, was not found to be significant (p = 0.27). In the cases where balloon-to-vessel ratio exceeded 1.0 (n = 35), multivariate analysis showed that the use of NSE PTA scoring balloon and pressure ratio before BPA were significantly correlated with Δ Pressure ratio (β coefficient: 0.047, 95% CI: 0.0016 to 0.093, p = 0.043 and β coefficient: −0.60, 95% CI: −0.78 to −0.42, p < 0.01, respectively).

Conclusions

Although NSE PTA scoring balloon was safe, there was no significant pressure gradient improvement with NSE PTA scoring balloon compared to conventional BPA. Nevertheless, the NSE PTA scoring balloon showed effective blood-flow improvement in the case of large balloon-to-vessel ratio.

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.

Oxygen inhalation can selectively dilate pulmonary arteries in patients with chronic thromboembolic pulmonary hypertension before balloon angioplasty

BACKGROUND

Pulmonary injury is a major complication of balloon pulmonary angioplasty (BPA) for chronic thromboembolic pulmonary hypertension (CTEPH). Lung injury after BPA can be exacerbated by a high mean pulmonary arterial pressure (PAP). Although oxygen inhalation is expected to lower mean PAP in patients with CTEPH, no relevant investigation has been conducted.

METHODS

Consecutive patients with CTEPH who underwent BPA were enrolled in this study. We evaluated the hemodynamics using right heart catheterization while breathing ambient air and with administration of 5 L/min oxygen for 10 min.

RESULTS

This study included 52 consecutive patients with CTEPH, of whom 23 (44%) were treated with specific pulmonary vasodilators. Exposure to oxygen was well tolerated. Oxygen administration significantly decreased mean PAP by 3.8 ± 3.2 mmHg (p<0.001) and pulmonary vascular resistance by 0.8 ± 1.8 Wood units (p<0.001). Moreover, the ratio of pulmonary vascular resistance to systemic vascular resistance was significantly reduced by 13.5% (p<0.001). Multivariate regression analysis identified baseline mean PAP (β = -0.427, p = 0.006) as the only significant predictor of decreased mean PAP under oxygen administration. No significant difference in oxygen effect on mean PAP was found between patients with and without vasodilators.

CONCLUSIONS

In patients with CTEPH, 5 L/min supplemental oxygen inhalation could decrease mean PAP significantly by selective pulmonary artery dilatation, regardless of the usage of vasodilators, and thus could be helpful to maximize the safety of BPA.

CLINICAL TRIAL REGISTRATION

UMIN Clinical Trials Registry (No.: UMIN000026882); URL: https://www.umin.ac.jp/ctr/index.htm.

A pilot cohort study assessing the feasibility of complete revascularization with balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension

Balloon pulmonary angioplasty improves prognosis by alleviating pulmonary hypertension in patients with chronic thromboembolic pulmonary hypertension, even with incomplete revascularization. However, hypoxia or the requirement for pulmonary vasodilators often remain even after pulmonary hypertension relief. With this cohort study, we aimed to examine whether complete revascularization by additional balloon pulmonary angioplasty on residual lesions, even after pulmonary hypertension relief, could resolve hypoxia or the requirement for pulmonary vasodilators. During complete revascularization with balloon pulmonary angioplasty in 42 patients with chronic thromboembolic pulmonary hypertension, we investigated therapeutic effects at baseline (T1), pulmonary hypertension relief phase (T2), and at 6 months post-final balloon pulmonary angioplasty (T3). The pulmonary hypertension relief phase was defined as the first time that a mean pulmonary artery pressure ≤ 25 mmHg or pulmonary vascular resistance ≤ 240 dyn-s/cm⁵ was reached in right heart catheterization before balloon pulmonary angioplasty. The partial pressure of oxygen increased progressively over T1, T2, and T3 (59.2±8.5, 69.0±9.7, and 80.0±9.5 mmHg, respectively; P<0.001 T2 vs. T3). Minimum oxygen saturation levels during the 6-minute walk distance test were 87% (81‒89%), 88% (84‒92%), and 91% (89‒93.3%), respectively (P<0.001 T2 vs. T3), with gradual increase in the 6-minute walk distance (346±125 m, 404±90 m, 454±101 m, respectively; P<0.001 T2 vs. T3). The percentages of patients using pulmonary vasodilators (54.8%, 45.2%, 4.8%, respectively; P<0.001 T2 vs. T3) and requiring oxygen therapy (26%, 26%, 7%, respectively; P = 0.008 T2 vs. T3) decreased significantly without hemodynamic exacerbation or major complications. Despite the discontinuation of pulmonary vasodilators, mean pulmonary artery pressure improved (36.0 [31.0‒41.3], 21.4±4.2, 18.5±3.6 mmHg, respectively; P<0.001 T2 vs. T3). Complete revascularization with balloon pulmonary angioplasty beyond pulmonary hypertension relief benefits patients with chronic thromboembolic pulmonary hypertension; it may improve oxygenation and exercise capacity, and reduce the need for pulmonary vasodilators and oxygen therapy.

Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension: advances in patient and lesion selection

PURPOSE OF REVIEW

Balloon pulmonary angioplasty (BPA) has been performed worldwide for patients who are ineligible for pulmonary endarterectomy (PEA). However, the technical details of BPA have not been standardized, and no international consensus regarding patient and lesion selection for BPA has been reached. Evidence for the combination of BPA with PEA or medical therapy is also lacking. This review highlights recent progress in BPA in terms of patient and lesion selection and the current procedural approach for BPA, including combination treatment.

RECENT FINDINGS

The indications for BPA have expanded with recent reports describing the improved safety and efficacy of BPA. Because lesions are generally present in all segmental and subsegmental pulmonary arteries, it is recommended to treat all the lesions to achieve desirable hemodynamic improvement. Selective pulmonary angiography is the gold standard for lesion selection in modern BPA aimed at total revascularization. Despite the lack of randomized controlled studies, combination treatment with BPA may be well tolerated and effective.

SUMMARY

BPA, alone or in combination with PEA or medical therapy, may be a treatment option for patients who are not candidates for monotreatment of PEA. However, further investigation is required to standardize patient and lesion selection for BPA.

Intravascular ultrasound-guided catheter-based aspiration thrombectomy in patients with acute submassive pulmonary embolism: A case series

Contrast pulmonary angiography by hand injection or power injection is widely used during catheter-based therapies for acute submassive and massive pulmonary embolism (PE). Particularly, in patients with pre-existing chronic kidney disease, this approach may present a prognostic challenge owing to a double-contrast load, initially during computed tomographic pulmonary angiography (CTPA), and during percutaneous treatment. Intravascular ultrasound (IVUS) has been used as an adjunctive imaging modality in the percutaneous treatment of chronic thromboembolic pulmonary hypertension, and in coronary and peripheral vascular interventions. We report a series of cases illustrating the use of IVUS in the management of acute PE. All five patients presented with an acute submassive PE with evidence of right ventricular (RV) strain (RV/LV ratio ≥ 0.90). Body mass index and B-type natriuretic peptide ranged from 18 to 47 kgm/m² and 56-932 pg/mL (ref. ≤ 78), respectively. Three of the five patients had renal impairment prior to the procedure (acute kidney injury, AKI, and chronic kidney injury, CKD). Post-catheter-directed pulmonary embolectomy there was a modest reduction in mean pulmonary artery pressure in all five patients (range: -4 mmHg to -9 mmHg). The first case serves as a proof of concept of IVUS use in acute PE. This case series demonstrates that an IVUS-only approach in the catheter-directed management of acute submassive PE is feasible and may be of particular importance in patients with pre-existing renal dysfunction.

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.

Balloon Pulmonary Angioplasty: State of the Art

Balloon pulmonary angioplasty (BPA) is a novel technique for the treatment of chronic thromboembolic pulmonary hypertension. While cardiologists need no introduction to the concept of balloon angioplasty, BPA has its own particular challenges. This article aims to provide the reader with an overview of BPA, starting with an introduction to chronic thromboembolic disease (CTED), the standard management of chronic thromboembolic pulmonary hypertension (CTEPH), technical challenges faced when performing BPA and the evidence base supporting its use. The second part of the article will focus on the future of BPA, in particular the areas where research is required to establish an evidence base to justify the role of BPA in CTEPH and CTED treatment.

Late Survival Benefit of Percutaneous Coronary Intervention Compared With Medical Therapy in Patients With Coronary Chronic Total Occlusion: A 10-Year Follow-Up Study

Background

As an initial treatment strategy, percutaneous coronary intervention (PCI) for coronary chronic total occlusion (CTO) did not show midterm survival benefits compared with optimal medical therapy (OMT). We sought to evaluate the benefit of PCI compared with OMT in patients with CTO over extended long‐term follow‐up.

Methods and Results

Between March 2003 and February 2012, 2024 patients with CTO were enrolled in a single‐center registry and followed for ≈10 years. We excluded patients with CTO who underwent coronary artery bypass graft (n=477) and classified patients into the CTO‐PCI group (n=883) or OMT group (n=664) according to initial treatment strategy. Patients with multivessel disease received PCI for obstructive non‐CTO lesions in both groups. In the CTO‐PCI group, 699 patients (79.2%) underwent successful revascularization. The CTO‐PCI group had a lower 10‐year rate of cardiac death (10.4% versus 22.3%; hazard ratio [HR], 0.44 [95% CI, 0.32–0.59]; P<0.001) than the OMT group. After propensity score matching analyses, the CTO‐PCI group had a lower 10‐year rate of cardiac death (13.6% versus 20.8%; HR, 0.64 [95% CI, 0.45–0.91]; P=0.01) than the OMT group. The relative reduction in cardiac death at 10 years was mainly driven by a relative reduction between 3 and 10 years (8.3% versus 16.6%; HR, 0.43 [95% CI, 0.27–0.71]; P<0.001) but not at 3 years (5.7% versus 5.0%; HR, 1.12 [95% CI, 0.63–2.00]; P=0.71). The beneficial effects of CTO‐PCI were consistent among subgroups.

Conclusions

As an initial treatment strategy, CTO‐PCI might reduce late cardiac death compared with OMT in patients with CTO. Extended follow‐up of randomized trials may confirm the findings of the present study.

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 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.