Cumulative sum analysis for the learning curve of minimally invasive mitral valve repair.

Minimally invasive mitral valve repair, recently, has become an alternative procedure to conventional mitral valve surgery, given its clinical benefits. Understanding the learning curve of a new procedure is important prior to its introduction. This study aimed to evaluate the learning curve for minimally invasive mitral valve repair and safety during the start-up period. The first 100 consecutive patients who underwent isolated minimally invasive mitral valve repair for mitral valve regurgitation were evaluated. The procedure was performed by a single surgeon at a single institution. Calculated cumulative sum analysis and cubic spline curve analysis were performed to evaluate the learning curves for the total procedure (TP), extracorporeal circulation (ECC), and aortic cross-clamping (ACC) times. ACC time was affected by the complexity of individual mitral valve repair; therefore, we analyzed the TP minus ACC (TP-ACC) time as a true learning curve by subtracting the ACC time from the TP time to exclude the difference of the complexity. Additionally, the operative outcome was assessed. Overall, the average TP, ECC, ACC, TP-ACC times were 211 ± 41, 133 ± 35, 108 ± 31, and 104 ± 4.9 min, respectively. All cubic spline curves depicted a decreasing trend, and improvements in TP, ECC, and ACC times were observed after 56 cases, while those of the TP-ACC time were observed after 68 cases. None of the patients experienced hospital mortality, reoperation for bleeding, respiratory failure, cerebral infarction with a disability, or recurrence of mitral valve regurgitation. Acute renal failure occurred in one patient. In conclusion, minimally invasive mitral valve repair can be introduced safely and provide a favorable outcome. However, a learning curve exists for the operative time factors. Approximately 60 operations are required to achieve a consistent operative time.

Caffeine poisoning successfully treated by venoarterial extracorporeal membrane oxygenation and emergency hemodialysis.

BACKGROUND: Caffeine overdose can cause life-threatening circulatory failure, neurological abnormalities, and ventricular fibrillation. We report the case of a patient with caffeine poisoning who was successfully treated with early hemodialysis and venoarterial extracorporeal membrane oxygenation. CASE PRESENTATION: A 43-year-old man who had ingested pills containing 20 g caffeine was transported to the hospital 100 min after ingestion. Hemodynamic collapse and refractory arrhythmia were most likely the potential complications. The patient developed ventricular fibrillation when placed in the left lateral decubitus position. Return of spontaneous circulation with defibrillation and introduction of venoarterial extracorporeal membrane oxygenation were followed by emergency dialysis, which led to rapid improvement in the clinical findings. CONCLUSION: Acute caffeine poisoning in a patient who developed an arrhythmia was successfully treated using an indwelling arterial and venous sheath followed by venoarterial extracorporeal membrane oxygenation.

Early and midterm results of minimally invasive aortic and mitral valve surgery via right mini-thoracotomy.

OBJECTIVES: There are few reports regarding minimally invasive aortic valve replacement concomitant with mitral valve surgery (MIAMVS). The aim of this study was to evaluate early and midterm MIAMVS results. METHODS: We reviewed the medical records of 21 consecutive patients (nine females, 43%) who underwent MIAMVS through a right mini-thoracotomy from December 2014 to April 2017. Mean patient age was 73 ± 7.4 years and four (19%) were New York Heart Association Class III or IV. Aortic stenosis and mitral valve insufficiency were the most common pathologies. All patients were followed for a mean period of 30 ± 8.5 months. RESULTS: The types of surgery consisted of aortic valve replacement with mitral valve repair in 11 (52%) patients, and replacement of both aortic and mitral valves in 10 (48%), while a tricuspid valve repair, was performed in four. No conversion to a full sternotomy was necessary in any of the cases. Postoperatively, the median intensive care unit and hospital stays were 4.7 and 11.8 days, respectively, with no in-hospital mortality. Following the initial treatment, all 21 patients were followed for a mean period of 30 ± 8.5 months (14-45 months). All patients returned to NYHA Class I or II following the procedure. During the follow-up period, there was no need for a heart valve reoperation for any of the patients and none showed recurrent mitral regurgitation (>mild), though one died from respiratory failure caused by pneumonia. CONCLUSIONS: MIAMVS can be performed via a right mini-thoracotomy, with acceptable early and midterm results expected. This may be a feasible alternative to the standard median sternotomy approach.

The learning curve of minimally invasive aortic valve replacement for aortic valve stenosis.

OBJECTIVE: Few clinical studies have been conducted to evaluate the learning curve of minimally invasive aortic valve replacement. The purpose of this study was to retrospectively analyze the learning curve of initial and isolated minimally invasive aortic valve replacement for aortic valve stenosis which performed at our institution. METHODS: This study included 126 patients who underwent initial and isolated minimally invasive aortic valve replacement via right infra-axillary mini thoracotomy for aortic valve stenosis. Patients were divided into the first 50 patients [1-50 cases: E group (n = 50)] and the last 76 patients [51-126 cases: L group (n = 76)]. RESULTS: A significantly shorter operative time (239.4 ± 35.2 min vs. 206.5 ± 25.5 min, P < 0.001), cardiopulmonary bypass time (151.1 ± 27.4 min vs. 126.9 ± 20.2 min, P < 0.001) and aortic cross-clamp time (115.2 ± 19.0 min vs. 93.9 ± 14.7 min, P < 0.001) were found in the L group. The learning curves of operative time, cardiopulmonary bypass time, and aortic cross-clamp time plateaued after 40 cases. CONCLUSIONS: Learning curves were observed in surgical processes such as operative time. A total of 40-50 cases are required to achieve a stable operative time. However, patient outcomes were not significantly different between the groups. This study could be helpful in introducing minimally invasive aortic valve replacement and designing training programs.

Left Internal Thoracic Artery Graft Assessment by Firefly Fluorescence Imaging for Robot-Assisted Minimally Invasive Direct Coronary Artery Bypass.

OBJECTIVE: The da Vinci Xi surgical system (Intuitive Surgical, Sunnyvale, CA, USA) cannot give tactile feedback to surgeons. This shortcoming may increase the risk of left internal thoracic artery (LITA) injury during its harvest. We utilized Firefly Fluorescence Imaging (Firefly) to assess LITA quality in robot-assisted minimally invasive direct coronary artery bypass (R-MIDCAB). METHODS: We retrospectively reviewed clinical records and intraoperative videos of 30 consecutive patients who underwent R-MIDCAB with LITA-left anterior descending (LAD) coronary bypass. All patients had post-harvest assessment of LITA blood flow by Firefly with 1 mL (2.5 mg/mL) of indocyanine green injection through a central line. RESULTS: Twenty-seven of the patients were male, mean age was 67.7 ± 10.7 years. In post-harvest assessment performed before transection of the distal LITA, blood flow in LITA was well visualized in 28 patients. In the remaining 2 patients, 1 had dissection and the other had severe spasm of the LITA. Firefly was also useful for locating LITA and LAD and for assessing blood flow of the graft after anastomosis. Time required for each Firefly assessment was approximately 20 seconds. There were no side effects or complications due to Firefly intraoperatively and postoperatively. Twenty-six patients had postoperative coronary computed tomography; LITA patency rate was 100% (26/26). CONCLUSION: Firefly is fast, simple, and effective for locating and assessing flow in LITA and LAD before and after anastomosis in R-MIDCAB.

Specific targeting of a naturally presented osteosarcoma antigen, papillomavirus binding factor peptide, using an artificial monoclonal antibody.

Osteosarcoma is a rare but highly malignant tumor occurring most frequently in adolescents. The prognosis of non-responders to chemotherapy is still poor, and new treatment modalities are needed. To develop peptide-based immunotherapy, we previously identified autologous cytotoxic T lymphocyte-defined osteosarcoma antigen papillomavirus binding factor (PBF) in the context of HLA-B55 and the cytotoxic T lymphocyte epitope (PBF A2.2) presented by HLA-A2. PBF and HLA class I are expressed in ∼90 and 70% of various sarcomas, respectively. However, the expression status of peptide PBF A2.2 presented by HLA-A2 on osteosarcoma cells has remained unknown because it is difficult to generate a specific probe that reacts with the HLA·peptide complex. For detection and qualification of the HLA-A*02:01·PBF A2.2 peptide complex on osteosarcoma cells, we tried to isolate a single chain variable fragment (scFv) antibody directed to the HLA-*A0201·PBF A2.2 complex using a naïve scFv phage display library. As a result, scFv clone D12 with high affinity (KD = 1.53 × 10(-9) M) was isolated. D12 could react with PBF A2.2 peptide-pulsed T2 cells and HLA-A2+PBF+ osteosarcoma cell lines and simultaneously demonstrated that the HLA·peptide complex was expressed on osteosarcoma cells. In conclusion, scFv clone D12 might be useful to select candidate patients for PBF A2.2 peptide-based immunotherapy and develop antibody-based immunotherapy.