Contrast-free left ventricular lead implantation for cardiac resynchronization therapy: a retrospective cohort study
Authors: Chouchane A , O'connor M , Bock M , Knoll K , Schmidt P , Schaarschmidt C , Krafft H , Storz T , Kottmaier M , Reents T , Bourier F , Lengauer S , Deisenhofer I , Kolb C , Lennerz C 
Published: November 2023

Abstract

Background
Left ventricular lead (LVL) implantation can be challenging in Cardiac Resynchronization Therapy (CRT). Therefore, contrast is commonly used to visualize the coronary venous system. However, contrast use is correlated with substantial risks such as contrast-induced nephropathy and anaphylactic reaction. Case studies suggest feasibility of LVL implantation without coronary sinus (CS) venography.

Purpose
We aimed to compare the procedure characteristics, outcome, and safety of contrast-free and contrast-aided LVL implantation.

Methods
346 LVL implantations performed between 2017 and 2019 were analyzed. 167 were contrast free (No-Contrast Group: NCG), and 179 were contrast-aided (Contrast Group: CG). The intervention duration, fluoroscopy duration, and radiation dose were evaluated. The primary outcome was procedural success. The secondary outcomes were LVL position, LVL threshold value, QRS duration and LVEF. Operative complications and lead revisions were surrogates for the intervention’s safety.

Results
The LVL implantation success rate varied from 62.9% in the NCG to 96.6% in the CG (Figure 1). Contrast-free interventions were associated with shorter procedure and fluoroscopy durations, and smaller radiation doses (100.8±41.0 vs 131.1±50.0min (p&lt;0.01), 15.7±11.2 vs 26.0±17.5min (p&lt;0.01) and 475.3±422.7 vs 897.3±779.1Gy.cm2 (p&lt;0.01) respectively). The intraoperative LVL threshold values were equivalent (0.96±0.65 in the NCG vs 1.05±0.65V in the CG, TOST-p&lt;0.01), and contrast use did not significantly influence the follow-up LVL threshold, QRS shortening and LVEF increase (1.11±0.55 vs 1.22±0.93V (p=0.62), -10.5±28.3 vs -13.2±26.3ms (p=0.16) and 2.3±8% vs 4.1±8.4% (p=0.40)). More intraoperative complications (CS dissection, perforation, mechanically-induced arrhythmia and other respiratory or circulatory problems) were observed during the contrast-aided procedures (9.5% in the CG versus 1.9% in the NCG, p=0.04). However, the postoperative complication rates (ICU admission, pericardial effusion, pneumothorax, infection and LVL revision) did not differ (9.5% in the NCG, 12.8% in the CG, p=0.55). In contrast-free LVL implantation failure cases, intraoperatively crossing over from the NCG to CG did not result in longer procedures or different intraprocedural complication rates (131.8±46.8 vs 131.1±50.0min in the CG (p=0.9) and 6.5% vs 9.5%, (p=0.6)).

Conclusion
Contrast-free LVL implantation was associated with shorter intervention and fluoroscopy durations and less radiation. Less intraoperative complications were observed without contrast, and the postoperative complication rate was similar to contrast-aided procedures. This technique was successful in almost 2/3 of the cases. In case of failure and crossover to contrast, the initial contrast free attempt did not result in more adverse events than in fully contrast-aided procedures. It is therefore reasonable to consider an initial contrast-free approach for CRT implantation.Compared groups