Recent advances in CT allow for safe, effective visualization of distal CTEPH lesions

In patients with chronic thromboembolic pulmonary hypertension (CTEPH), balloon pulmonary angioplasty (BPA) guided by cone-beam computed tomography (CBCT) or electrocardiogram (ECG)-gated area detector CT (ADCT) is efficacious and safe, according to research published online in the European Journal of Radiology. In addition, added these researchers, these new advanced CT techniques may also be useful in pre-BPA target lesion assessments.  

“The purpose of this study is to show whether BPA for webs and slit lesions detected only by CBCT and ADCT work or not,” said lead author Takeshi Ogo, MD, director, division of pulmonary circulation, and director, department of advanced medical research, National Cerebral and Cardiovascular Center, Osaka, Japan.

“We previously showed that CBCT and ADCT are new modalities to show distal lesions before BPA. We did not know whether these web and slit lesions are the target lesions for BPA or not. Also, there were not specific modalities to show distal CTEPH lesions previously. Current approach is just relying on the image of pulmonary angiography (PAG). However, pulmonary angiography images miss the distal CTEPH lesions. Even selective pulmonary angiography (PAG) will miss the distal web lesions. Intravascular modalities are not used for detecting web and slit lesions for BPA in clinical practice. Conventional PAG does not have good image quality to detect distal disease. IVUS cannot detect web lesions and OCT is used only for research purposes,” he added.

Dr. Ogo and colleagues retrospectively reviewed data from 80 consecutive patients with inoperable CTEPH who underwent BPA guided by CBCT or ECG-gated ADCT for target lesion assessment. They reviewed clinical and hemodynamic data, including procedure complications, before BPA, at 3 months after, and 1 year after BPA.

In all, 385 BPA sessions were performed, with 4.8 sessions per patient, for subsegmental arterial lesions (n=1,155), segmental arterial lesions (n=738), and lobar arterial lesions (n=4) as identified by CBCT or ECG-gated ADCT.

At 3 months and 1 year after BPA, they observed significant improvements in symptoms, 6-minute walk distances, brain natriuretic peptide levels, exercise capacity, and hemodynamics. They saw no instances of death or cardiogenic shock, and found a low rate of severe wire perforation (0.3%) and severe reperfusion edema (0.3%).

Dr. Ogo noted: “Some of the leading European CTEPH centers (France, Germany, Poland, etc.) started BPA programs, which we supported 2 to 3 years ago. Now, the number of BPA has been growing rapidly since last year. Also, leading CTEPH centers all over the world are interested in BPA. Some of US CTEPH centers, including UCSD, are also interested in BPA. They visit our center, and I [have] proctored in some of their centers. They have just started in small cases. I guess BPA will be a killer treatment for inoperable CTEPH patients in USA, [and] the number of BPA is growing and growing in Japan and Europe now.”

As for the differences between CBCT and ECG-gated ADCT for target lesion assessment, Dr. Ogo explained, “CBCT and ADCT are alternative in terms of the image quality. The difference in these two modalities is that CBCT is more invasive as it needs pigtail catheter insertion to pulmonary artery. ADCT is less invasive like normal CT scan.”

He also outlined the approach to BPA, in light of each patient requiring nearly 5 sessions.

“For safe treatment, we do BPA in a staged and stepwise manner. Patients are very sick at first treatment. If some complications happen in the severe condition, it will be critical sometimes. So, we start BPA very carefully with small balloons and limit the area to treat. Then we treat more after patient hemodynamics improved. Also, there are many pulmonary vessels to treat. Radiation exposure and dose of contrast medium agent is another limitation in each treatment,” Dr. Ogo explained.

“CTEPH distal lesions are under-diagnosed so far. Using CBCT/ADCT is quite useful for detecting distal lesions in CTEPH. Also, BPA for these distal lesions detected by CBCT/ADCT improves patient symptoms, exercise capacity, and hemodynamics dramatically with extremely safe profile,” concluded Dr. Ogo.