DISCUSSION
The major 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 also 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 were 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 extraction of chronically implanted leads with fibrotic adhesions to the vascular and/or 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 re-imbursement 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 by using TightRailTM mechanical dilator sheath; complete success rate was 91%, and major complication rate was 2%12. In our study, the complete procedural and clinical success rates were 86.9% and 90.5% using TightRailTMsystem without rescue methods. Complete clinical success was increased to 98.2% with use of rescue snaring system. Major and minor complication rates were 1.2% and 8.2%, respectively, in accordance with 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 used technique, extraction tool, patient and lead characteristics7,9,13. In our study, the need for rescue tools was observed in 11.2% of Evolution® group and 8.2% of TightRailTM group (p>0.05). Higher lead dwell time and lead burden were associated with an increased need for rescue tools and major complication rates 14. TLE indications of lead dysfunction and infection were also more prevalent in patients with lead breakage, incomplete lead extraction, and need for rescue snaring tools 9. In our study, the lead dwell time, lead burden, leads with passive fixation, and infection parameters were significantly higher in patients with procedural failure who required rescue snaring tool.
In our study, major complications were totally 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 at the TightRailTM group, major vascular lacerations in 3 patients by 0.99% at 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 was followed by 0.06%, and vascular laceration was followed by 0.4-0.9%, and our data was similar to this registry 8. Patients with cardiac tamponade had both atrial and ventricular PM electrodes with passive fixation mechanism in which lead dwell time was ten years. The myocardial avulsion was thought to be during 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, and cardiac avulsion with tamponade is the most common major complication by 61.2%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, and because of mostly hematoma, which didn’t require drainage, this condition did not cause any clinical problems.
There was no difference between TightRailTM and Evolution® groups in regard to all-cause mortality at long-term follow-up in our study. To the best of our knowledge, our study is unique with its largest sample size of 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 were 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 require a learning curve and 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 was collected retrospectively in this cohort study. Second, the impact of learning curve on outcomes of Evolution® group which was available at first could not be ignored. Third, data for procedure and fluoroscopy time were not available for all participants. Fourth, second generation EvolutionR/L mechanical dilator sheath couldn’t be used during the study period. At last, the availability of TLE devices mainly depends on the re-imbursement policy of our National Social Security System which limits the randomization. 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 TLE tool should be based on the operator preferance/experience, availability and re-imbursement of the devices. Continued investigation is required to compare safety, success, and complication rates with other techniques.