Epicardial left ventricular lead implantation in cardiac resynchronization therapy patients via a video‐assisted thoracoscopic technique: Long‐term outcome

Abstract Background Epicardial placement of the left ventricular (LV) lead via a video‐assisted thoracoscopic (VAT) approach is an alternative to the standard transvenous technique. Hypothesis Long‐term safety and efficacy of VAT and transvenous LV lead implantation are comparable. To test it, we reviewed our experience and we compared the outcomes of patients who underwent implantation with the two techniques. Methods The VAT procedure is performed under general anesthesia, with oro‐tracheal intubation and right‐sided ventilation, and requires two 5 mm and one 15 mm thoracoscopic ports. After pericardiotomy at the spot of the epicardial target area, pacing measurements are taken and a spiral screw electrode is anchored at the final pacing site. The electrode is then tunneled to the pectoral pocket and connected to the device. Results 105 patients were referred to our center for epicardial LV lead implantation. After pre‐operative assessment, 5 patients were excluded because of concomitant conditions precluding surgery. The remaining 100 underwent the procedure. LV lead implantation was successful in all patients (median pacing threshold 0.8 ± 0.5 V, no phrenic nerve stimulation) and cardiac resynchronization therapy was established in all but one patient. The median procedure time was 75 min. During a median follow‐up of 24 months, there were no differences in terms of death, cardiovascular hospitalizations or device‐related complications vs the group of 100 patients who had undergone transvenous implantation. Patients of both groups displayed similar improvements in terms of ventricular reverse remodeling and functional status. Conclusions Our VAT approach proved safe and effective, and is a viable alternative in the case of failed transvenous LV implantation.

area, pacing measurements are taken and a spiral screw electrode is anchored at the final pacing site. The electrode is then tunneled to the pectoral pocket and connected to the device.
Results: 105 patients were referred to our center for epicardial LV lead implantation.
After pre-operative assessment, 5 patients were excluded because of concomitant conditions precluding surgery. The remaining 100 underwent the procedure. LV lead implantation was successful in all patients (median pacing threshold 0.8 ± 0.5 V, no phrenic nerve stimulation) and cardiac resynchronization therapy was established in all but one patient. The median procedure time was 75 min. During a median followup of 24 months, there were no differences in terms of death, cardiovascular hospitalizations or device-related complications vs the group of 100 patients who had undergone transvenous implantation. Patients of both groups displayed similar improvements in terms of ventricular reverse remodeling and functional status.
Conclusions: Our VAT approach proved safe and effective, and is a viable alternative in the case of failed transvenous LV implantation.

| INTRODUCTION
Epicardial placement of left ventricular (LV) lead has been proposed as an alternative approach in the case of failure of the transvenous approach during cardiac resynchronization therapy (CRT) device implantation. In our center we developed a minimally invasive videoassisted thoracoscopic (VAT) technique. We reviewed our experience in order to evaluate the safety and efficacy of this technique. We also assessed long-term safety and efficacy by comparing the outcome of the study group with that of a control group of patients who underwent standard transvenous LV lead implantation.

| Patient selection
The study was approved by the Institutional Review Board and all subjects provided written consent. Patients underwent baseline evaluation, which included demographics and medical history, clinical examination, 12-lead electrocardiogram, and echocardiogram. Patients were also evaluated by means of a CT scan to rule out any thoraco-pulmonary disease, spirometry with diffusing capacity of the lung for carbon monoxide, and anesthesiology evaluation. In all patients, previous LV lead implantation had been unsuccessful, owing to unsuitable coronary or subclavian venous anatomy, LV lead dislodgement or failure, phrenic nerve stimulation not correctable by reprogramming, or lead extraction because of infection.

| Surgical technique and approach
The technique has been previously described. 1 In summary, after a general anesthetic had been administered, a double-lumen endotracheal tube was inserted. With the patient in a right lateral decubitus position (90 ) and on single-lung ventilation, three ports (2 × 5 mm;

| Patient management
Patients were extubated in the operating room or in the Intensive Care Unit. The chest tube was removed 12 to 24 hours after surgery.
No redo surgery was necessary. After discharge, clinic visits were scheduled every 6 months.

| Control group
A group of 100 consecutive patients who underwent successful transvenous CRT implantation in our center was used as a control group.

| Endpoints
Primary end-points were: time to death due to any cause and time to the combination of death and cardiovascular hospitalization. Additional endpoints were: device-related complications, LV ejection fraction and volume change, NYHA class, and ventricular pacing parameters.

| Statistical analysis
Descriptive statistics are reported as means ± SD for normally distributed continuous variables, or medians with 25th to 75th percentiles in the case of skewed distribution. Differences between mean data were compared by means of a T-test for Gaussian variables. The Mann-Whitney test and the Wilcoxon non-parametric test were used to compare non-Gaussian variables for independent and paired samples, respectively. Differences in proportions were compared by applying Chi-square analysis or Fisher's exact test, as appropriate. Event rates were summarized by constructing Kaplan-Meier curves. The log-rank test was applied in order to evaluate differences between trends. A P < .05 was considered significant for all tests. All statistical analyses were performed by means of SPSS Statistics, software, version 20 (IBM Corp, New York, New York). In the transvenous group, the median LV lead pacing threshold was 1.1 V at 0.5 ms. The final position of the LV lead was lateralanterolateral. Table 2 compares procedural data of the two groups.

| Follow-up
In the thoracoscopic group, 21 deaths occurred during a median follow-up period of 24 months (IQR, 13-39); in the transvenous group, 27 deaths occurred during a median follow-up of 32 months (IQR, . The rates of death due to any cause were comparable between the groups (Figure 1; log-rank test, P = .193). The rates of death due to any cause and cardiovascular hospitalization were also comparable between the groups (Figure 1; log-rank test, P = .949).
Moreover, the risk of device-related complications was similar between the groups. Figure 2 shows the survival from device-related complications in both groups (log-rank test, P = .783). In the thoracoscopic group, we recorded five infections (requiring system revision only in one patient), four pocket hematomas (not requiring system revision), one right ventricular lead dislodgement, one system failure, and one replacement of the LV lead. In the transvenous group, six patients had LV lead dislodgement, three had pocket erosion, two had right ventricular lead dislodgement, one had right atrial lead dislodgement, and one system failure.
In both groups, significant reverse remodeling of the LV was observed in terms of increased LV ejection fraction and reduced LV volumes ( Table 3). Patients of both groups similarly improved in their functional status, as evidenced by a reduction of patients in NYHA class III-IV at 1-year follow-up. The pacing parameters remained satisfactory in both groups (Table 3).

| Study limitations
The main limitation is its lack of randomization. The study group consisted of consecutive patients who were referred to our center for epicardial LV lead implantation. The number of patients who initially underwent an attempt of transvenous implantation at the referring centers is unknown. The control group consisted of consecutive patients who underwent successful transvenous CRT implantation in our center. As data on operative complications in this group were not available for comparison, we limited our comparison to long-term safety and outcome.