The feasibility and safety of fluoroscopy-guided percutaneous intramyocardial gene injection in porcine heart

Background: Catheter-based transendocardial gene injection would be useful for the delivery of genes into the heart. We examined the feasibility and safety of percutaneous intramyocardial gene injections with fluoroscopic guidance alone. Methods: We performed the procedure through an 8F arterial sheath inserted into the left carotid artery. In protocol 1, a mixture of India ink and normal saline was injected through a needle injection catheter in six pigs. We monitored blood pressure and ECG continuously during the procedure. Echocardiography, left ventriculography, and coronary angiography were performed. All pigs were sacrificed 2 days later and hearts were harvested. In protocol 2, a mixture of India ink and plasmid encoding CAT gene was injected in the same manner in eight pigs. Myocardial tissue was obtained 7 days after the procedure to assess gene expression. In protocol 3, four pigs were intentionally needle-perforated in the ventricular wall and were observed for 7 days. Results: In protocol 1, there was no significant hemodynamic changes or serious arrhythmias during the procedure. Echocardiography and angiography revealed no evidence indicating pericardial effusion or wall motion abnormalities. Harvested hearts revealed one intramyocardial hematoma in a total of 36 injection sites. In protocol 2, the gene expression could be identified in 39 sites out of 48 injections after 7 days. In protocol 3, no animal showed signs indicating cardiac tamponade during the observation period. Conclusions: Our data suggest that fluoroscopy-guided percutaneous intramyocardial gene injection is a feasible and safe procedure, with no indication of associated significant hemodynamic changes, arrhythmias, or mortality.