DISCUSSION
The significant findings of our single-center large-scale cohort study were as follows; (1) the TLE using either Evolution®or TightRailTM hand-powered rotational mechanical dilator sheaths was associated with high efficacy and acceptable complication rates. Both procedural/clinical success and major/minor complication rates were similar between Evolution® or TightRailTM groups. Additionally, there was no difference in all-cause mortality rates at long-term follow-up between each group. The presence of heart failure, baseline coagulopathy, and impaired renal functions was associated with an increased risk of all-cause mortality.
Among various available TLE tools, hand-powered rotating mechanical dilator sheaths are preferred by many operators during the extraction of chronically implanted leads with fibrotic adhesions to the vascular and endocardial surfaces 8,9. In our study, the TLE has been performed in patients with median lead dwell time of five years by using either first-generation Evolution® or TightRailTM systems at different time intervals because of the availability and governmental reimbursement policy. Evolution® system has been associated with excellent clinical and procedural success with low complication rates in previous studies 9-11. In our study, complete clinical success and procedural successes were 99.2% and 94.0%, respectively, as in other studies, complete clinical and procedural success rates have been mostly >95% 8,11. The clinical and procedural success rates were 88.0% and 84.2% without using rescue methods in our study. In previous studies, complete success rate without using rescue methods and tools was in the range of 69%-94.5%, and these studies major and minor complication rate was reported as 0%-4.2% and 0%-12%, respectively 4,6,10. In our Evolution® group, major and minor complication rates were 3.8% and 10.5%, respectively, with compatible low complication rates as studies in the literature. The data about the TightRailTM system is limited in the literature. In a small observational study, the complete procedural and clinical success rates without rescue methods were 96% and 100%, respectively5. In a larger retrospective multi-center study, chronically implanted 147 leads in 100 patients were extracted using TightRailTM mechanical dilator sheath; complete success rate was 91%, and the major complication rate was 2%12. In our study, the complete procedural and clinical success rates were 86.9% and 90.5% using the TightRailTM system without rescue methods. Complete clinical success was increased to 98.2% with the use of a rescue snaring system. Major and minor complication rates were 1.2% and 8.2%, respectively, per studies in the literature.
In the literature, the need for rescue tools during TLE with mechanical dilator sheaths was highly variable (range of 2.4-27.1%) due to the used technique, extraction tool, patient, and lead characteristics7,9,13. In our study, the need for rescue tools was observed in 11.2% of the Evolution® group and 8.2% of the TightRailTM group (p>0.05). Higher lead dwell time, and the lead burden was associated with an increased need for rescue tools and major complication rates 14. Involved leads in the lead fracture or infection categories were also more prevalent than other categories of TLE indications in patients with lead breakage, incomplete lead extraction, and need for rescue snaring tools 9. As in line with previous studies, the lead dwell time, lead burden, leads with passive fixation, and infection parameters were significantly higher in patients with procedural failure who required a rescue snaring tool in our study.
In our study, major complications were observed in 7 patients (2.3%). Additionally, procedure-related death was seen in 2 patients (0.66%), which was due to intracranial hemorrhage (n=1) in the TightRailTM group and haemothorax (n=1) in the Evolution® group. Besides these deaths, major complications included cardiac tamponade in one patient in the TightRailTM group, major vascular lacerations in 3 patients by 0.99% in the Evolution® group, a cerebrovascular accident by 0.33% in Evolution®group. In the ELECTRa registry, procedure-related death was seen in the range of 0.3-0.8% rates, and our study data is similar to this registry. In the ELECTRa registry, the cerebrovascular accident and vascular laceration were followed by 0.06% and 0.4-0.9%, respectively, and our data was similar to this registry 8. Patients with cardiac tamponade had both atrial and ventricular PM electrodes with a passive fixation mechanism in which lead dwell time was ten years. We thought that the lead dwell time of ten years was likely the relevant clinical factor for such a critical life-threatening complication. The myocardial avulsion was thought to be during the extraction of the atrial electrode, which was successfully repaired surgically. In previous studies, massive pericardial effusion was reported by 0.25-0.59%, which was 0.33% in our study accordingly. In the ELECTRa registry analysis, 84.5% of major complications were cardiovascular avulsion 15. In our study, 71% of major complications were cardiovascular complications, and cardiac avulsion was observed in two patients by 28.5%. In the ELECTRa registry, the minor complication rate was reported as 5% (range 4.3-5.7%), which was 9.2% in our study. The majority of minor complications in our study was pocket hematoma by 60%, but the drainage was only required in 2 (0.6%) of the patients In previous studies, the rate of hematoma requiring drainage was in the range of 0.9-1.6%16,17. In our study, the minor complication rate was higher than the ELECTRa registry. However, most of these cases were pocket hematoma requiring no drainage which did not cause any clinical problems.
There was no difference between TightRailTM and Evolution® groups regarding the all-cause mortality rate at long-term follow-up in our study. If the TightRailTM group was followed for the same duration as the Evolution® group, it is likely higher all-cause mortality would be seen in the TightRailTM population. Moreover, there was a significant separation of the survival curves of both groups with the log-rank test, which was thought to be due to a sicker population with more hypertension, diabetes mellitus, CAD, HFrEF, NYHA class II-IV, and lower LVEF of TightRailTM group compared to Evolution® group. To the best of our knowledge, our study is unique, with its largest sample size of the TightRailTM group in the literature, in addition to long-term mortality outcomes of both device technology. Higher leukocyte count, lead burden, and lead dwell time were associated with a higher risk of procedural failure, and presence of heart failure, coagulopathy, and chronic renal disease was associated with a higher risk of all-cause mortality in our study. In previous studies, it was observed that the lead burden associated with a 3.5 fold increased risk of any complication. Moreover, TLE for infection and high CRP levels were found to be associated with all-cause mortality 18,19. In a large-scale study with extracted 5521 leads that evaluated risk factors of procedural failure, major complications, and all-cause mortality, low platelet counts and higher INR levels (>1.2) were associated with major complications and 30-day death20. Furthermore, heart failure and renal dysfunction increased the 30-day mortality by 1.3-8.5 and 4.8 fold, respectively21,22.
Our study results have important clinical implications. The TLE using either TightRailTM or Evolution®mechanical dilator sheaths can be performed with an excellent clinical/procedural success and acceptable complication rates. These findings suggest that these extraction tools should be used by experienced operators with a cardiothoracic surgery team on standby to cope with any complication.
Our study results should be interpreted with some limitations. First, the study groups were non-randomized, and the data were collected retrospectively in this cohort study. Second, the impact of the learning curve on the outcomes of the Evolution® group, which was available at first, could not be ignored. Third, data for procedure and fluoroscopy time as markers of the case complexity were not available for all participants. Fourth, second-generation EvolutionR/L mechanical dilator sheath could not be used during the study period. At last, the availability of TLE devices mainly depends on the reimbursement policy of our National Social Security System, which limits the randomization. Thus, the study compared two non-contemporaneous periods where the different devices were available rather than a direct comparison. Furthermore, non-rotational dissection tools and laser sheath were not available in our country.
In conclusion, our results showed that the TLE by using either TightRailTM or Evolution®hand-powered rotational mechanical dilator sheath systems was highly effective with acceptable safety results. However, rescue extraction tools and backup cardiothoracic surgery support should be available on site. The selection of the TLE tool should be based on the operator preference/experience, availability, and reimbursement of the devices. Continued investigation is required to compare safety, success, and complication rates with other techniques.