Space hierarchy theorem revised

AbstractWe show that, for an arbitrary function h(n) and each recursive function ℓ(n), that are separated by a nondeterministically fully space constructible g(n), such that h(n)∈Ω(g(n)) but ℓ(n)∉Ω(g(n)), there exists a unary language L in NSPACE(h(n)) that is not contained in NSPACE(ℓ(n)). The same holds for the deterministic case.The main contribution to the well-known Space Hierarchy Theorem is that (i) the language L separating the two space classes is unary (tally), (ii) the hierarchy is independent of whether h(n) or ℓ(n) are in Ω(logn) or in o(logn), (iii) the functions h(n) or ℓ(n) themselves need not be space constructible nor monotone increasing, (iv) the hierarchy is established both for strong and weak space complexity classes. This allows us to present unary languages in such complexity classes as, for example, NSPACE(loglogn·log∗n)⧹NSPACE(loglogn), using a plain diagonalization

Phase II Multicenter Clinical Trial of Pulmonary Metastasectomy and Isolated Lung Perfusion with Melphalan in Patients with Resectable Lung Metastases

IntroductionThe 5-year overall survival rate of patients undergoing complete surgical resection of pulmonary metastases (PM) from colorectal cancer (CRC) and sarcoma remains low (20–50%). Local recurrence rate is high (48–66%). Isolated lung perfusion (ILuP) allows the delivery of high-dose locoregional chemotherapy with minimal systemic leakage to improve local control.MethodsFrom 2006 to 2011, 50 patients, 28 male, median age 57 years (15–76), with PM from CRC (n = 30) or sarcoma (n = 20) were included in a phase II clinical trial conducted in four cardiothoracic surgical centers. In total, 62 ILuP procedures were performed, 12 bilaterally, with 45 mg of melphalan at 37°C, followed by resection of all palpable PM. Survival was calculated according to the Kaplan–Meier method.ResultsOperative mortality was 0%, and 90-day morbidity was mainly respiratory (grade 3: 42%, grade 4: 2%). After a median follow-up of 24 months (3–63 mo), 18 patients died, two without recurrence. Thirty patients had recurrent disease. Median time to local pulmonary progression was not reached. The 3-year overall survival and disease-free survival were 57% ± 9% and 36% ± 8%, respectively. Lung function data showed a decrease in forced expiratory volume in 1 second and diffusing capacity of the alveolocapillary membrane of 21.6% and 25.8% after 1 month, and 10.4% and 11.3% after 12 months, compared with preoperative values.ConclusionCompared with historical series of PM resection without ILuP, favorable results are obtained in terms of local control without long-term adverse effects. These data support the further investigation of ILuP as additional treatment in patients with resectable PM from CRC or sarcoma

Thoracoscopic vs. catheter ablation for atrial fibrillation: long-term follow-up of the FAST randomized trial

Aims: Our objectives were to compare effectiveness and long-term prognosis after epicardial thoracoscopic atrial fibrillation (AF) ablation vs. endocardial catheter ablation, in patients with prior failed catheter ablation or high risk of failure. Methods and results: Patients were randomized to thoracoscopic or catheter ablation, consisting of pulmonary vein isolation with optional additional lines (2007–2010). Patients were reassessed in 2016/2017, and those without documented AF recurrence underwent 7-day ambulatory electrocardiography. The primary rhythm outcome was recurrence of any atrial arrhythmia lasting >30 s. The primary clinical endpoint was a composite of death, myocardial infarction, or cerebrovascular event, analysed with adjusted Cox proportional hazard ratios (HRs). One hundred and 24 patients were randomized with 34% persistent AF and mean age 56 years. Arrhythmia recurrence was common at mean follow-up of 7.0 years, but substantially lower with thoracoscopic ablation: 34/61 (56%) compared with 55/63 (87%) with catheter ablation [adjusted HR 0.40, 95% confidence interval (CI) 0.25–0.64; P < 0.001]. Additional ablation procedures were performed in 8 patients (13%) compared with 31 (49%), respectively (P < 0.001). Eleven patients (19%) were on anti-arrhythmic drugs at end of follow-up with thoracoscopy vs. 24 (39%) with catheter ablation (P = 0.012). There was no difference in the composite clinical outcome: 9 patients (15%) in the thoracoscopy arm vs. 10 patients (16%) with catheter ablation (HR 1.11, 95% CI 0.40–3.10; P = 0.84). Pacemaker implantation was required in 6 patients (10%) undergoing thoracoscopy and 3 (5%) in the catheter group (P = 0.27). Conclusion: Thoracoscopic AF ablation demonstrated more consistent maintenance of sinus rhythm than catheter ablation, with similar long-term clinical event rates

Totally thoracoscopic ablation for atrial fibrillation:a systematic safety analysis

Item does not contain fulltex

Endosonography With or Without Confirmatory Mediastinoscopy for Resectable Lung Cancer:A Randomized Clinical Trial

PURPOSE:Resectable non-small-cell lung cancer (NSCLC) with a high probability of mediastinal nodal involvement requires mediastinal staging by endosonography and, in the absence of nodal metastases, confirmatory mediastinoscopy according to current guidelines. However, randomized data regarding immediate lung tumor resection after systematic endosonography versus additional confirmatory mediastinoscopy before resection are lacking.METHODS:Patients with (suspected) resectable NSCLC and an indication for mediastinal staging after negative systematic endosonography were randomly assigned to immediate lung tumor resection or confirmatory mediastinoscopy followed by tumor resection. The primary outcome in this noninferiority trial (noninferiority margin of 8% that previously showed to not compromise survival, Pnoninferior &lt;.0250) was the presence of unforeseen N2 disease after tumor resection with lymph node dissection. Secondary outcomes were 30-day major morbidity and mortality.RESULTS:Between July 17, 2017, and October 5, 2020, 360 patients were randomly assigned, 178 to immediate lung tumor resection (seven dropouts) and 182 to confirmatory mediastinoscopy first (seven dropouts before and six after mediastinoscopy). Mediastinoscopy detected metastases in 8.0% (14/175; 95% CI, 4.8 to 13.0) of patients. Unforeseen N2 rate after immediate resection (8.8%) was noninferior compared with mediastinoscopy first (7.7%) in both intention-to-treat (Δ, 1.03%; UL 95% CIΔ, 7.2%; Pnoninferior =.0144) and per-protocol analyses (Δ, 0.83%; UL 95% CIΔ, 7.3%; Pnoninferior =.0157). Major morbidity and 30-day mortality was 12.9% after immediate resection versus 15.4% after mediastinoscopy first (P =.4940).CONCLUSION:On the basis of our chosen noninferiority margin in the rate of unforeseen N2, confirmatory mediastinoscopy after negative systematic endosonography can be omitted in patients with resectable NSCLC and an indication for mediastinal staging.</p

Interventions to prevent postoperative atrial fibrillation in Dutch cardiothoracic centres:a survey study

Introduction: Postoperative atrial fibrillation (POAF) is a common phenomenon following cardiac surgery. In this study, we assessed current preventive strategies used by Dutch cardiothoracic centres, identified common views on this matter and related these to international guidelines. Methods: We developed an online questionnaire and sent it to all cardiothoracic surgery centres in the Netherlands. The questionnaire concerned the management of POAF and the use of pharmaceutical therapies (beta-blockers and calcium antagonists) and non-pharmaceutical methods (posterior left pericardiotomy, pericardial flushing and epicardial botulinum toxin type A injections). Usage of electrical cardioversions, anticoagulants and left atrial appendage closure were also enquired. Results: Of the 15 centres, 14 (93%) responded to the survey and 13 reported a POAF incidence, ranging from 20 to 30%. Of these 14 centres, 6 prescribed preoperative AF prophylaxis to their patients, of which non-sotalol beta-blockers were prescribed most commonly (57%). Postoperative medication was administered by all centres and included non-sotalol beta-blockers (38%), sotalol (24%), digoxin (14%), calcium antagonists (13%) and amiodarone (10%). Only 2 centres used posterior left pericardiotomy or pericardial flushing as surgical manoeuvres to prevent POAF. Moreover, respondents expressed the need for guidance on anticoagulant use. Conclusion: Despite the use of various preventive strategies, the reported incidence of POAF was similar in Dutch cardiothoracic centres. This study highlights limited use of prophylactic amiodarone and colchicine, despite recommendations by numerous guidelines, and restricted implementation of surgical strategies to prevent POAF.</p