P2848Electrical reconnections after pulmonary vein isolation with or without contact force-guided catheters: a comparison of the proficiency of atrial fibrillation ablation

Background Atrial fibrillation (AF) ablation is the most commonly performed catheter ablation (CA) procedure today. The 2015 ACC/AHA/HRS Advanced Training Statement reported that the success rate of AF ablation is higher in high-volume centers than in low-volume centers. We tested whether the procedure proficiency of each operator was associated with the outcome of AF ablation, and whether the ablation outcome depended on whether contact force (CF)-guided catheters were used or not, in a high-volume center. Methods We conducted a retrospective observational study including all AF patients who underwent radiofrequency CA with or without CF support since 2016 at our hospital. The patients who underwent CA at other hospitals or underwent a balloon or surgical ablation in the first session were excluded. Each ipsilateral pulmonary vein (PV) pair was divided into 8 segments. The reconnection numbers and sites of the PV segment were evaluated in the second session. Operators were divided into the experienced group (≥100 AF cases/year, at least every 3 years) and developing group (other than the experienced group), respectively. Results Among 728 patients who underwent an initial AF ablation and were followed for 510±306 days, 131 (90 males, 65±10 years) received a second ablation procedure and were analyzed. A total of 260 and 264 PV isolations (PVI) were performed by the experienced and developing group operators in the initial ablation, respectively. Compared to the experienced group, the developing group had a longer procedure time for the PVI (35±15 vs. 28±10 min, p<0.001), higher frequency of reconnections of the PVs (73% vs. 59%, p=0.01) and higher number of reconnection gaps (2.1±2.0 vs. 1.5±2.0, p=0.02), respectively. There were no significantly differences in the number of gaps between the catheters with and without CF (1.6±2.0 vs. 1.4±2.0, p=0.65) in the experienced group, however, in the developing group a smaller total number of gaps (1.5±1.6 vs. 2.4±2.1, p=0.006) and less frequency reconnection gaps of the posterosuperior segment of the right PV (10% vs. 45%, p=0.005) were seen with catheters with CF than without. There was no significant difference in the procedure time for the PVI between catheters with and without CF. Conclusions The operator proficiency may predict the outcome after AF ablation even in high-volume centers. It is preferable to perform PVI with a CF-sensing catheter for operators without adequate proficiency. Acknowledgement/Funding JSPS KAKENHI Grant Number JP18K15865

Single-Institution Early Experience and Learning Curve with Robotic Liver Resections

Robotic liver resection is being introduced with its potential to overcome limitations of conventional laparoscopy. This study was undertaken to document early experience and learning curve of robotic liver resection in our institution. All patients undergoing liver resection between 2013 and 2017 were prospectively followed. Patients were divided into three consecutive tertiles (cohort I–III). Thirty-three patients underwent robotic liver resection within the study period. Twenty-four per cent of patients underwent formal right or left hemihepatectomy, 21 per cent underwent sectionectomy, 6 per cent underwent central hepatectomy, and the remainder underwent non-anatomical liver resection. Formal hemihepatectomy and right posterosuperior segment resection were undertaken in two patients in cohort I, four patients in cohort II, and four patients in cohort III. Two cases were converted to “open” operation. Operative time was 172 (194.5 ± 65.1) minutes in cohort I, 222 (247.8 ± 109.8) minutes in cohort II, and 280 (302.5 ± 84.9) minutes in cohort III, reflecting increasing degree of technical complexity. Estimated blood loss decreased significantly throughout the cohorts, being 400 mL, 200 mL, and 100 mL in cohorts I to III, respectively. Major intraoperative complications were not seen. Three patients experienced postoperative complications, resulting in a single mortality. Length of hospital stay was three days, with two patients being readmitted within 30 days. Robotic technique for liver resection is feasible and safe. It offers good short-term clinical outcomes, including for patients who require major liver resection. As the proficiency developed, a notable improvement in technically ability to undertake more complex resections with decreasing blood loss and minimal morbidity was seen.

Complete Surgical Resection of a Leiomyosarcoma Arising from the Inferior Vena Cava

A 76-year-old Japanese man was referred to our hospital with chief complaint of right hypochondoralgia. Abdominal ultrasound showed a retroperitoneal tumor in the suprarenal region of the right kidney. Computed tomography revealed an enhanced lobular tumor with irregular, circumscribed, and indistinct border. Ultrasound-guided biopsy was performed. The tumor consisted of spindle-shaped cells with a giant nucleus and multinuclear cells. The diagnosis was leiomyosarcoma by immunohistochemical staining. The patient underwent surgery accessed by a right eighth intercostal thoracoabdominal incision. The tumor was completely resected, accompanied by removal of the posterosuperior segment of the right hepatic lobe, right adrenal gland, and a portion of the inferior vena cava (IVC). The histopathologic diagnosis was leiomyosarcoma arising from the IVC. We present a rare case of a successfully managed leiomyosarcoma of the IVC. This case suggests the importance of curative surgical resection of the tumor due to low efficacy of adjuvant chemotherapy for leiomyosarcoma.