Procedural Success of Left Ventricular Lead Placement for Cardiac Resynchronization Therapy: A Meta-Analysis.

OBJECTIVES: The goal of this study was to assess the contemporary and historical success rates of transvenous left ventricular (LV) lead placement for cardiac resynchronization therapy (CRT), their change over time, and the reasons for failure. BACKGROUND: In selected patients, CRT improves morbidity and mortality, but the placement of the LV lead can be technically challenging. METHODS: A literature search was used to identify all studies reporting success rates of LV lead placement for CRT via the coronary sinus (CS) route. A total of 164 studies were identified, and a meta-analysis was performed. RESULTS: The studies included 29,503 patients: 74% (95% confidence interval [CI]: 72% to 76%) were male; their mean age was 66 years (95% CI: 65 to 67); their mean New York Heart Association functional class was 2.8 (95% CI: 2.7 to 2.9); the mean LV ejection fraction was 26% (95% CI: 25% to 28%); and the mean QRS duration was 155 ms (95% CI: 150 to 160). The overall rate of failure of implantation of an LV lead was 3.6% (95% CI: 3.1 to 4.3). The rate of failure in studies commencing before 2005 was 5.4% (95% CI: 4.4% to 6.5%), and from 2005 onward it was 2.4% (95% CI: 1.9% to 3.1%; p < 0.001). Causes of failure (reported for 39% of failures) also changed over time. Failure to cannulate and navigate the CS decreased from 53% to 30% (p = 0.01), and the absence of any suitable, acceptable vein increased from 39% to 64% (p = 0.007). The proportion of leads in a lateral or posterolateral final position (reported for 26% of leads) increased from 66% to 82% (p = 0.004). CONCLUSIONS: The reported rate of failure to place an LV lead via the CS has decreased steadily over time. A greater proportion of failures in recent studies are due to coronary venous anatomy that is unsuitable for this technique.