Double stapling method for closure of intraoperative alveolar air leakage adjacent to the staple line: a randomized experimental study on ex vivo porcine lungs

BackgroundAlveolar air leakage from a pleural defect around the staple line is one of the complications after wedge resection of the lung. An intraoperative closure of the pleural defect by suturing can cause additional pleural rupture due to tension of the pleura adjacent to staple lines. Therefore, we have introduced a novel closure method for pleural defect adjacent to the staple line, named the double stapling method. This study compared the efficacy of two closure methods; the double stapling method and conventional suturing method with pledgets using ex vivo porcine lungs.MethodsThe double stapling method involves closing the pleural defect by suturing the two parallel staple lines at both sides of the pleural defect. This method was developed to distribute the pleural tension around the needle holes of suturing. As a model of pleural defect adjacent to the staple line after wedge resection, wedge resection of the caudal lobe of left porcine lungs was performed, and a superficial square pleural defect (10 mm × 10 mm) adjacent to the staple line was made by scalpel. The defect was closed using the following two methods: (I) suturing with pledgets (n=10); and (II) double stapling method (n=10). The lobe was inflated in water at an airway pressure of 20, 25, and 30 cmH₂O; closure success or failure was judged by the absence or presence of air leakage.ResultsThe closure success was confirmed in 2 (20%) out of 10 cases in the suturing with pledgets group and 9 (90%) out of 10 in the double stapling method group (P=0.007). In 4 out of 10 cases in the suturing with pledgets group, new pleural clefts longer than 3 mm were created around the needle holes of suturing.ConclusionsEx vivo experiments have suggested the superiority of the double stapling method for the intraoperative closure of alveolar air leakage adjacent to the staple line after wedge resection, compared to conventional suturing with the pledget method.     

A tumor metastasis‐associated molecule TWIST1 is a favorable target for cancer immunotherapy due to its immunogenicity

Although neoantigens are one of the most favorable targets in cancer immunotherapy, it is less versatile and costly to apply neoantigen‐derived cancer vaccines to patients due to individual variation. It is, therefore, important to find highly immunogenic antigens between tumor‐specific or associated antigens that are shared among patients. Considering the cancer immunoediting theory, immunogenic tumor cells cannot survive in the early phase of tumor progression including two processes: elimination and equilibrium. We hypothesized that highly immunogenic molecules are allowed to be expressed in tumor cells after an immune suppressive tumor microenvironment was established, if these molecules contribute to tumor survival. In the current study, we focused on TWIST1 as a candidate for highly immunogenic antigens because it is upregulated in tumor cells under hypoxia and promotes tumor metastasis, which is observed in the late phase of tumor progression. We demonstrated that TWIST1 had an immunogenic peptide sequence TWIST1_140–162, which effectively activated TWIST1‐specific CD4⁺ T‐cells. In a short‐term culture system, we detected more TWIST1‐specific responses in breast cancer patients compared with in healthy donors. Vaccination with the TWIST1 peptide also showed efficient expansion of TWIST1‐reactive HTLs in humanized mice. These findings indicate that TWIST1 is a highly immunogenic shared antigen and a favorable target for cancer immunotherapy.     

Electrophysiologic characteristics of atrial tachycardia originating from the right pulmonary veins or posterior right atrium: double potentials obtained from the posterior wall of the right atrium can be useful to predict foci of atrial tachycardia in right pulmonary veins or posterior right atrium

INTRODUCTION: The right pulmonary veins (RPVs) and posterior wall of the right atrium (PRA) are anatomically located adjacent to each other. The aim of this study was to demonstrate the electrophysiologic characteristics of atrial tachycardia (AT) originating from the PRA or RPVs. METHODS AND RESULTS: A total of 26 consecutive patients with AT originating from the RPVs or PRA underwent detailed atrial endocardial mapping and successful radiofrequency catheter ablation. Eight foci were found in the PRA and 18 foci in the RPVs. Analysis of P wave configuration showed that lead V1 was the most helpful in distinguishing the AT foci between these two sites. In all cases, double potential (DP) configurations were recorded from several electrodes of a multielectrode catheter placed in the PRA, and the first DP component (FP) was the earliest potential recorded from the right atrium during the tachycardia. The amplitude of the FP was higher than that of the second DP component (SP) for AT foci originating in the PRA, whereas the reverse occurred for those in the RPV. The activation sequence of the FP was from superior to inferior for the AT foci in the superior RPV, whereas the reverse occurred for the AT foci in the inferior RPV. CONCLUSION: P wave configuration in lead V1 is helpful in distinguishing AT foci between those originating in the PRA and RPVs. The DPs obtained from the PRA can be useful in predicting whether AT foci originate from the PRA or RPVs.     

Clinical significance of left atrial geometry in dilated cardiomyopathy patients: A cardiovascular magnetic resonance study

BackgroundClinical significance of left atrial (LA) function and geometry in patients with dilated cardiomyopathy (DCM) remains uncertain.HypothesisLA geometric parameters assessed by cardiac magnetic resonance (CMR) predict the prognosis in patients with DCM.MethodsThe present study included patients with DCM and sinus rhythm who underwent CMR between December 2007 and April 2018. LA volume was measured using CMR. LA sphericity index was computed as the ratio of the measured maximum LA volume by the volume of a sphere with maximum LA length diameter.ResultsWe included 255 patients in this study. During the mean follow‐up of 3.92 years, hospitalization for HF occurred in 37 patients. The LA sphericity index was significantly higher in patients with hospitalization for HF than in those without (0.78 ± 0.35 vs. 0.58 ± 0.18, p < .001). Multivariable Cox regression analysis identified a higher LA sphericity index as an independent predictor of hospitalization for HF. Patients were categorized based on the median of LA sphericity index. The Kaplan–Meier curve showed that patients with a high LA sphericity index (≥0.57) had a significantly higher risk of hospitalization for HF than those with a low LA sphericity index (<0.57).ConclusionLA sphericity index was an independent predictor of hospitalization for HF. Assessment of LA geometric parameters might be useful for risk stratification in patients with DCM.     

Clinical impact of complete atrioventricular block in patients with ST‐segment elevation myocardial infarction

Complete atrioventricular block (CAVB) is a common complication of ST‐segment elevation myocardial infarction (STEMI). Although STEMI patients complicated with CAVB had a higher mortality in the thrombolytic era, little is known about the impact of CAVB on STEMI patients who underwent primary percutaneous coronary intervention (PCI). The study aimed at evaluating the clinical impact of CAVB on STEMI patients in the primary PCI era. We consecutively enrolled 1295 STEMI patients undergoing primary PCI within 24 hours from onset. Patients were divided into two groups according to the infarct location: anterior STEMI (n = 640) and nonanterior STEMI (n = 655). The outcomes were all‐cause death and major adverse cardiocerebrovascular events (MACCE) with a median follow‐up period of 3.8 (1.7–6.6) years. Eighty‐one patients (6.3%) developed CAVB. The incidence of CAVB was lower in anterior STEMI patients than in nonanterior STEMI (1.7% vs 10.7%, p < .05). Anterior STEMI patients with CAVB had a higher incidence of all‐cause deaths (82% vs 20%, p < .05) and MACCE (82% vs 25%, p < .05) than those without CAVB. Although higher incidence of all‐cause deaths was found more in nonanterior STEMI patients with CAVB compared with those without CAVB (30% vs 18%, p < .05), there was no significant difference in the incidence of MACCE (24% vs 19%). Multivariate analysis showed that CAVB was an independent predictor for all‐cause mortality and MACCE in anterior STEMI patients, but not in nonanterior STEMI. CAVB is rare in anterior STEMI patients, but remains a poor prognostic complication even in the primary PCI era.