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Safety Window for Effective Lesion Crossing in Patients With Chronic Thromboembolic Pulmonary Hypertension
Sidney J Perkins1, Miguel Funes2, Daniel Cheah3
1Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
Insights
A safety window exists for crossing chronic thromboembolic pulmonary hypertension (CTEPH) lesions. Less force is needed to penetrate CTEPH lesions than pulmonary arterial walls, aiding angioplasty device development.
Area of Science:
- Cardiovascular Medicine
- Interventional Cardiology
- Pulmonary Hypertension Research
Background:
- Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension (CTEPH) faces challenges due to limitations in safe and effective lesion-crossing tools.
- Understanding the mechanical properties of CTEPH lesions and pulmonary arteries is crucial for developing new interventional devices.
Purpose of the Study:
- To determine a safety window for intraluminal crossing devices in CTEPH by evaluating the piercing properties of pulmonary arterial walls and CTEPH lesions.
- To characterize the histopathologic features of CTEPH lesions.
Main Methods:
- Procurement of pulmonary artery specimens from 9 patients undergoing pulmonary endarterectomy.
- Ex vivo measurement of tissue penetration force using a 0.38-mm diameter probe on arterial wall and intraluminal CTEPH lesion samples.
- Concurrent histological analysis of the specimens.
Main Results:
- Penetrating intraluminal CTEPH lesions required significantly less force (0.30 ± 0.04 N) compared to the pulmonary arterial wall (1.75 ± 0.10 N).
- Histology revealed intimal hyperplasia with calcification and hemosiderin in the arterial wall, and organized thrombus within the lumen of CTEPH lesions.
Conclusions:
- The pulmonary arterial wall is fragile and susceptible to perforation during instrumentation.
- A lower penetration force for CTEPH lesions suggests a safety margin for developing lesion-crossing devices.
- These findings support the potential for effective balloon pulmonary angioplasty in CTEPH through improved device design.
Background:
Balloon pulmonary angioplasty for chronic thromboembolic pulmonary hypertension (CTEPH) is limited by a lack of safe and effective tools for crossing these lesions. We aim to identify a safety window for an intraluminal crossing device in this vascular bed by studying the piercing properties of pulmonary arterial vessel walls and intraluminal CTEPH lesion specimens. As a secondary objective, we also describe the histopathologic features of CTEPH lesions.
Methods:
Specimens were procured from 9 patients undergoing pulmonary endarterectomy. The specimens were subsampled and identified grossly as arterial wall or intraluminal CTEPH lesions. The force needed for tissue penetration was measured using a 0.38-mm (0.015-in) diameter probe in an ex vivo experimental model developed in our lab. Concurrent histology was also performed.
Results:
The mean force needed to penetrate the arterial wall and intraluminal CTEPH lesions was 1.75 ± 0.10 N (n = 121) and 0.30 ± 0.04 N (n = 56), respectively (P < .001). Histology confirmed the presence of intimal hyperplasia with calcium and hemosiderin deposition in the arterial wall as well as an old, organized thrombus in the lumen.
Conclusions:
The pulmonary arterial wall is friable and prone to perforation during instrumentation with workhorse coronary guide wires. However, the results of this study demonstrate that a much lower force is needed for the 0.38-mm (0.015-in) probe to penetrate an intraluminal CTEPH lesion compared to pulmonary arterial intima. This finding suggests the existence of a safety window for lesion-crossing devices, enabling effective balloon pulmonary angioplasty.
