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Updated: Jul 16, 2026
Direct Pressure Monitoring Accurately Predicts Pulmonary Vein Occlusion During Cryoballoon Ablation
Published on: February 26, 2013
Microbubbles in the pulmonary artery generated during experimental hepatic radiofrequency ablation is correlated with
Lars Frich1, Per Steinar Halvorsen, Helge Skulstad
1Interventional Centre, Rikshospitalet University Hospital, N-0027 Oslo, Norway. lars.frich@labmed.uio.no
Purpose:
Microbubbles in hepatic veins during hepatic radiofrequency (RF) ablation is a well-known observation. In this experimental study, we examined the association between microbubbles in the pulmonary artery and alterations in mean pulmonary arterial pressure (MPAP) during hepatic RF ablation with a perfusion electrode system.
Materials And Methods:
Sixteen domestic pigs were included in the study. Twelve animals were randomly assigned to RF ablation with maintained (n = 6) or interrupted (n = 6) hepatic inflow. Four animals were assigned to a control group where interruption of hepatic inflow but no RF ablation was performed. Microbubbles in the pulmonary artery were recorded by transesophageal echocardiography and scored according to the number of bubbles per heart cycle. Mean pulmonary arterial pressure was continuously registered by a pulmonary artery catheter. The association between the microbubble score and increase in MPAP during ablation was examined using Spearman's rank correlation coefficient.
Results:
Echocardiographic recordings were acquired in 9 of 12 animals in the two treatment groups. Microbubbles in the pulmonary artery were present in four animals in each treatment group. Mean pulmonary arterial pressure increased from a baseline value of 17.7 mm Hg +/- 2.3 to a maximum value of 29.7 mm Hg +/- 7.7 during ablation (P = .018). A significant association was found between the microbubble score and increase in MPAP (P = .001).
Conclusions:
Microbubbles were detected in the pulmonary artery during hepatic RF ablation both during maintained and interrupted hepatic inflow. A strong association was found between microbubbles in the pulmonary artery and increased MPAP. The clinical implications of our findings are to be determined.
Insights
Microbubbles in the pulmonary artery during hepatic radiofrequency ablation correlate with increased mean pulmonary arterial pressure. This study in pigs shows a strong association between microbubble presence and pressure changes, warranting further clinical investigation.
Area of Science:
- Interventional Radiology
- Cardiopulmonary Physiology
- Medical Imaging
Background:
- Microbubbles are commonly observed in hepatic veins during radiofrequency (RF) ablation.
- The presence and impact of these microbubbles in the pulmonary circulation during the procedure are not fully understood.
Purpose of the Study:
- To investigate the association between microbubbles in the pulmonary artery and changes in mean pulmonary arterial pressure (MPAP).
- To examine this relationship during hepatic RF ablation using a perfusion electrode system in an experimental model.
Main Methods:
- Sixteen domestic pigs underwent hepatic RF ablation with either maintained or interrupted hepatic inflow, or served as controls.
- Microbubbles in the pulmonary artery were detected and scored using transesophageal echocardiography.
- Mean pulmonary arterial pressure was continuously monitored via a pulmonary artery catheter.
- Spearman's rank correlation coefficient was used to analyze the association between microbubble score and MPAP increase.
Main Results:
- Microbubbles were detected in the pulmonary artery in animals undergoing hepatic RF ablation.
- Mean pulmonary arterial pressure significantly increased during ablation (from 17.7 to 29.7 mm Hg).
- A strong, significant association was identified between the pulmonary microbubble score and the increase in MPAP (P = .001).
Conclusions:
- Microbubbles are present in the pulmonary artery during hepatic RF ablation, irrespective of hepatic inflow management.
- A significant correlation exists between the number of pulmonary microbubbles and elevated mean pulmonary arterial pressure.
- The clinical significance of these findings requires further evaluation.
