Prevention of serious air embolism during cryoballoon ablation; risk assessment of air intrusion into the sheath by catheter selection and change in intrathoracic pressure: An ex vivo study

Abstract

Introduction One cause of cerebral infarction during cryoballoon ablation is the entry of air into a sheath due to the use of inappropriate catheters. It is known that the left atrial pressure of patients with obstructive sleep apnea syndrome can be negative. However, the effects of catheter selection and negative pressure changes in the sheath on air intrusion are not yet well understood. The aim of this study was to evaluate how catheter selection and negative pressure changes affect air intrusion and to perform countermeasures for air intrusion. Methods and Results This experiment used siphon principle to create negative pressure in the sheath. Noncryoablation catheters (not designed exclusively for cryoballoon ablation) and cryoballoon catheters were investigated. Catheters were inserted into the sheath and then removed. Thereafter, the amount of air in the sheath was measured. For catheters producing significantly larger amounts of air intrusion, the catheters were inserted via a long sheath in the sheath (sheath‐in‐sheath technique) and the same procedures were repeated. We found that the amount of air intrusion through most of the noncryoablation catheters was significantly larger than that through cryoablation catheters. An increase in the magnitude of negative pressure in the sheath resulted in a proportional increase in air intrusion, but the sheath‐in‐sheath technique significantly reduced air intrusion. Conclusion The amount of air intrusion increased when using catheters with complicated tip shapes and thin outer diameters and when the magnitude of negative pressure in the sheath increased. The sheath‐in‐sheath technique may be an effective countermeasure.

Effect of preventing air intrusion on silent strokes during atrial fibrillation ablation using a mini‐basket catheter

“…Deneke et al also reported that exchanging catheters over a transseptal sheath during LA ablation contributed to the increase in the occurrence of SCEs 30 . Further, experimental studies demonstrated that the amount of air intrusion increased when using multielectrode catheters with complex shapes and an inserter during insertion of a circular mapping catheter, 3,4,7 and the number of small air bubbles increased during sheath flushing at fast speeds, as compared to that at slow speeds 4 …”

“…To the best of our knowledge, so far there have been no previous studies focusing on the strategies for preventing air bubble intrusion into the LA during an RF‐based AF catheter ablation. Some risk factors associated with air emboli during cryoballoon‐based AF ablation have been reported in clinical and experimental studies: (a) air bubbles attached to the surface of the balloon, (b) air intrusion during inserting catheters into transseptal sheaths and flushing the sheaths with heparinized saline, (c) rapid sheath flushing, (d) multielectrode catheters with complex shapes, and (e) use of an inserter during insertion of a circular mapping catheter 2–7 …”

“…Left atrial (LA) catheter ablation of atrial fibrillation (AF) has a potential risk of cerebral embolisms during the ablation procedure 1 . Air bubble intrusion into the LA through transseptal sheaths is one of the reasons for cerebral embolic complications and usually occurs during inserting or exchanging catheters over transseptal sheaths and flushing the sheaths with heparinized saline 2–7 . Experimental studies have demonstrated that the use of multielectrode catheters with complex shapes and an inserter during insertion of catheters increased the amount of air intrusion 3,4,7 .…”

“…Air bubble intrusion into the LA through transseptal sheaths is one of the reasons for cerebral embolic complications and usually occurs during inserting or exchanging catheters over transseptal sheaths and flushing the sheaths with heparinized saline 2–7 . Experimental studies have demonstrated that the use of multielectrode catheters with complex shapes and an inserter during insertion of catheters increased the amount of air intrusion 3,4,7 . Further, our previous study suggested that the use of a mini‐basket catheter (IntellaMap Orion; Boston Scientific, Marlborough, MA) with the high‐resolution electroanatomic mapping system (Rhythmia; Boston Scientific) may increase the risk of silent cerebral embolisms during LA ablation 8 .…”

ST‐segment elevation during arrhythmia ablations—A review

“…In such situations relying only on patient‐reported symptoms intraoperatively would yield inconsistent results. Furthermore, it has been reported that air emboli can occur after long apnea episodes produced by sedation, right before a loud snore with an increase in negative intrathoracic pressure, causing air to enter via the hemostatic valves or while exchanging circular mapping catheters 24,25 . Air emboli can travel to the coronary arteries or the cerebral arteries and cause hemodynamic collapse or stroke 24 .…”