Catheter-based myocardial gene transfer utilizing nonfluoroscopic electromechanical left ventricular mapping

OBJECTIVES This study investigated the feasibility and safety of percutaneo us, catheter-based myocardial gene transfer. BACKGROUND Direct myocardial gene transfer has, to date, required direct in jection via an open thoracotomy. METHODS Electroanatomical mapping was performed to establish the site of le ft ventricular (LV) gene transfer. A steerable, deformable 7F catheter with a 27G needle, which can be advanced 3 to 5 mm beyond its distal tip, was t hen directed to previously acquired map sites, the needle was advanced, and injections were made into the LV myocardium. RESULTS In two pigs in which methylene blue dye was injected, discretely st ained LV sites were observed at necropsy in each pig, corresponding to the injection sites indicated prospectively by the endocardial map. In six pigs in which the injection catheter was used to deliver plasmid using cytomega lovirus promoter/enhancer, encoding nuclear-specific LacZ gene (pCMV-nlsLac Z) (50 mu g/ml) to a single LV myocardial region, peak beta-galactosidase a ctivity after five days (relative light units [RLU], mean 135,333 +/- 28,23 9, range = 31,508 to 192,748) was documented in the target area of myocardi al injection in each pig. Percutaneous gene transfer of pCMV-nlsLacZ (50 mu g/ml) was also performed in two pips with an ameroid constrictor applied t o the left circumflex coronary artery; in each pig, peak beta-galactosidase activity after five days (214,851 and 23,140 RLU) was documented at the in jection site. All pigs survived until sacrifice, and no complications were observed with either the mapping or the injection procedures. CONCLUSIONS Percutaneous myocardial gene transfer can be successfully achie ved in normal and ischemic myocardium without significant morbidity or mort ality. These findings establish the potential for minimally invasive cardio vascular gene transfer. (C) 1999 by the American College of Cardiology.