[Management of patent foramen ovale in non-cardiac surgery]. / Gestione della pervietà del forame ovale nella chirurgia non cardiaca.

Patent foramen ovale (PFO) is a remnant of normal fetal anatomy which may persist into adulthood, mostly asymptomatic. In some adults, PFO may result in a potential for shunting venous thromboembolism to the arterial circulation; less frequently it can cause interatrial, right-to-left shunting of deoxygenated blood. The pathogenesis of several medical conditions is related to the presence of PFO. Some randomized clinical trials have shown evidence of benefit for device closure as compared with medical therapy in patients with cryptogenic stroke. The literature reported several cases of carbon dioxide embolism during general laparoscopic surgery and sometimes stroke after laparoscopic or neurosurgery but there are neither prospective studies addressing these issues, nor randomized clinical trials assessing the effectiveness of pharmacotherapy or interventional procedures at decreasing risk. The European position paper suggests routine monitoring in non-cardiac surgery of patients with a PFO and no actual indications for closure. This article aims to further stratify the risk of periprocedural stroke and paradoxical embolism in this category of patients.

Navigator nurse implementation within a fast track program of liver resections: How to improve the healthcare service and perioperative results.

BACKGROUND: The introduction into the clinical practice of the navigator nurse (NaNu) to address the task of counseling and short term follow-up help the effective implementation of the fast track protocol. The aim of the present study was to investigate the impact of the standardization of the NaNu's role in patients undergoing liver surgery. METHODS: Patients undergoing elective liver surgery for all diagnosis and approach, from 2015, received counseling and postoperative follow-up by NaNu and constituted the study group (n = 890). This group was compared with the control group (n = 712) including patients treated in the era before the implementation of the NaNu role (2011-2014). Outcome was evaluated in terms of discrepancy between functional recovery and discharge, number of ER accesses, number of readmissions. RESULTS: Preoperative characteristics of patients and disease, as well as type of resection and postoperative outcomes were similar between the two groups. The proportion of laparoscopic cases was higher in the study group (51.2% vs. 32% in the control). Time for discharge, interval between functional recovery and discharge, number of ER accesses and number of readmissions were reduced in the study group. Benign diagnosis, absence of complications, laparoscopic approach and presence of NaNu were independent predictors of shorter length of stay. The positive effect of NaNu's activation was recorded in patients with complications and undergoing open surgery. CONCLUSION: The implementation of NaNu's role has allowed to us optimize the level of healthcare service offered to patients. The wider benefit was offered in the setting of complex patients.

Feasibility, safety and efficacy of COVID-19 severe acute respiratory distress syndrome management without invasive mechanical ventilation.

BACKGROUND: COVID-19 acute respiratory distress syndrome (ARDS) is often managed with mechanical ventilation (MV), requiring sedation and paralysis, with associated risk of complications. There is limited evidence on the use of high flow nasal cannula (HFNC). We hypothesized that management of COVID-19 ARDS without MV is feasible. METHODS: Included were all adult patients diagnosed with COVID-19 ARDS, with PaO2/FiO2 ratio <100 at admission, and whose management was initially performed without MV. We evaluated need for intubation during ICU stay, mortality and hospital/ICU length of stay (LOS). RESULTS: Out of 118 patients, 41 were managed only with HFNC from hospital admission (and at least during first 24 hours in ICU) and had a PaO2/FiO2 ratio <100 (72.9±13.0). Twenty-nine out of 41 patients never required MV: 24 of them survived and were discharged home. Their median ICU LOS was 11 (7-17) days, and their hospital LOS was 29 (18-45) days. We identified PaO2/FiO2 ratio at ICU admission as the only significant predictor for need for MV during ICU stay. We also identified age, length of non-invasive respiratory support before ICU admission, mean value of PaO2/FiO2 ratio during first half and whole ICU stay as predictors of mortality. CONCLUSIONS: It is safe to monitor in ICU and use HFNC in patients affected by COVID-19 ARDS who initially present data suggesting an early need for intubation. The 41 patients admitted with a PaO2/FiO2 ratio <100 and initially treated only with HFNC show a 22% mortality that is in the lower range of what is reported in recent literature.

Clinical Impact and Predictors of Aneurysmal Rebleeding in Poor-Grade Subarachnoid Hemorrhage: Results From the National POGASH Registry.

BACKGROUND: Scarce data are available regarding rebleeding predictors in poor-grade aneurysmal subarachnoid hemorrhage (aSAH). OBJECTIVES: To investigate predictors and clinical impact of rebleeding in a national multicentric poor-grade aSAH. METHODS: Retrospective analysis of prospectively collected data from the multicentric Poor Grade Aneurysmal Subarachnoid Hemorrhage Study Group (POGASH) registry of consecutive patients treated from January 1, 2015, to June 30th, 2021. Grading was defined as pretreatment World Federation of Neurological Surgeons grading scale IV-V. Ultra-early vasospasm (UEV) was defined as luminal narrowing of intracranial arteries not due to intrinsic disease. Rebleeding was defined as clinical deterioration with evidence of increased hemorrhage on subsequent computed tomography scans, fresh blood from the external ventricular drain, or deterioration before neuroradiological evaluation. Outcome was assessed by the modified Rankin Scale. RESULTS: Among 443 consecutive World Federation of Neurological Surgeons grades IV-V patients with aSAH treated within a median of 5 (IQR 4-9) hours since onset, rebleeding occurred in 78 (17.6%). UEV (adjusted odds ratio [OR] 6.8, 95% CI 3.2-14.4; P < .001) and presence of dissecting aneurysm (adjusted OR 3.5, 95% CI 1.3-9.3; P = .011) independently predicted rebleeding while history of hypertension (adjusted OR 0.4, 95% CI 0.2-0.8; P = .011) independently reduced its chances. 143 (32.3) patients died during hospitalization. Rebleeding emerged, among others, as an independent predictor of intrahospital mortality (adjusted OR 2.2, 95% CI 1.2-4.1; P = .009). CONCLUSION: UEV and presence of dissecting aneurysms are the strongest predictors of aneurysmal rebleeding. Their presence should be carefully evaluated in the acute management of poor-grade aSAH.

Development of a predictive model for unplanned intensive care unit admission after pancreatic resection within an enhanced recovery pathway.

BACKGROUND: It is unclear whether routine postoperative admission to the intensive care unit (ICU) can improve outcomes for patients undergoing elective pancreatic surgery. Aim of the study was to determine preoperative and intraoperative predictors of unplanned ICU access in patients undergoing pancreatectomy treated within an established enhanced recovery pathway (ERP) and compare outcomes between direct and late ICU admission. METHODS: A retrospective observational study was conducted on adult patients who underwent pancreatic resection (2015-2019) within an ERP. Patients with preoperatively planned ICU admission were excluded from the study. Multiple multivariate logistic regression models were constructed to verify the association of preoperative and intraoperative variables with study outcomes. RESULTS: The study included 1486 consecutive patients (cancer diagnosis 60%, pancreaticoduodenectomy 60%; laparoscopic approach 20%; vascular resection 9%). Sixty-six (4.4%) patients had an unplanned ICU admission. Direct admission occurred in 22 (33%) patients and late ICU admission in 44 (67%) patients. Mortality was significantly lower in direct admission group (n = 3, 14%) compared to late admission (n = 25, 57%; p > 0.001). A comprehensive model including preoperative and intraoperative variables identified ASA score ≥ 3 (OR 5.59, p value < 0.001), history of hypertension (OR 2.29, p = 0.029), chronic obstructive pulmonary disease (OR 3.05, p = 0.026), proximal pancreatic resection (OR 2.79, p value 0.046), multivisceral resection (OR 8.86, p value < 0.001), high intraoperative blood loss (OR 1.01 per ml, p < 0.001), and increased serum lactate at the end of surgery (OR 1.25, p = 0.017) as independent factors associated with ICU admission. Area under the ROC curve was 0.891. CONCLUSION: Patient comorbidities, surgical complexity, and lactic acidosis at the end of surgery were associated with unplanned postoperative ICU admission. Late ICU admission had very high mortality rates compared to direct admission. Our findings suggest that patients with a combination of preoperative and intraoperative risk factors could benefit from upfront postoperative ICU admission to potentially improve postoperative outcomes.

Efficacy of a rational algorithm to assess allergy risk in patients receiving the BNT162b2 vaccine.

Among 6146 hospital employees, 118 subjects with severe allergic background were identified through a screening questionnaire and stratified into 3 groups (Low-risk (LR), Intermediate (IR) and High-risk (HR) group), based on their allergic anamnesis. Data reports on hypersensitivity reactions (HypR) have been collected in both allergic and non-allergic subjects. Seventeen patients (14%) in the allergic population had a HypR after the first, the second or both doses. Skin manifestations were the most frequent ones. Allergic events were more frequent in HR (35%) than IR (10%; p = 0.005) or LR (0%; p = 0.074) subjects. No patient had anaphylaxis. All patients completed the vaccination schedule. 13 HypR occurred in patients without severe allergic background (13/6028, 0,2%) including one (1/6148, 0.016% of total population) WAO grade-4 anaphylaxis. Our data suggest that BNT162b2 mRNA Covid-19 vaccine is relatively safe also in patients with severe allergic background; however, some precautions are required for high-risk patients.

Immunosuppressive strategies in invasively ventilated ARDS COVID-19 patients.

BACKGROUND: COVID-19 is associated with elevated levels of inflammatory cytokines. We present the characteristics and outcomes of patients treated in the Intensive Care Unit (ICU) with immunosuppressive drugs, either tocilizumab or anakinra compared with controls. METHODS: A single-center observational prospective study on ICU invasively ventilated COVID-19 patients. The primary outcome was the clinical improvement at day 28. A Bayesian framework was employed, and all analyses were adjusted for confounders. RESULTS: Sixty-one consecutive invasively ventilated patients were included, nine (14.7%) received tocilizumab and 15 (24.6%) received anakinra. Over the first seven days, tocilizumab was associated with a greater decrease in C-reactive protein (P<0.001). After adjusting for confounders, the probability of clinical improvement at day 28 compared to control was 7∙6% (OR=0.36 [95% CrI: 0.09-1.46]) for tocilizumab and 40.9% (OR=0.89 [95% CrI: 0.32-2.43]) for anakinra. At day 28, the probability of being in a better clinical category was 2.5% (OR=2.98 [95% CrI: 1.00-8.88]) for tocilizumab, and 49.5% (OR=1.00 [95% CrI: 0.42-2.42]) for anakinra. CONCLUSIONS: In invasively ventilated COVID-19 patients, treatment with anakinra was associated with a higher probability of clinical improvement compared to tocilizumab; however, treatment with either drug did not result in clinically meaningful improvements compared with controls.

Impact of care pathway adherence on recovery following distal pancreatectomy within an enhanced recovery program.

BACKGROUND: In bowel surgery, adherence to enhanced recovery program (ERP) has been associated with improved recovery. The objective of this study was to evaluate the impact of adherence to ERP elements on outcomes, and identify factors associated with successful recovery following distal pancreatectomy (DP). METHODS: Data for 376 patients who underwent DP managed within an ERP including 16 perioperative elements were reviewed. Primary endpoint was successful recovery, a composite outcome defined as length of hospital stay≤7 days, no severe complications nor readmissions. RESULTS: Patients had a mean (SD) overall adherence of 76 (14)%. Overall, 166 (44%) patients had a successful recovery. There was a positive association between overall adherence and successful recovery (OR 1.19, 95%CI 1.08-1.31 for every additional element, p = 0.001), while an inverse relationship was found with comprehensive complication index (8% reduction, 95%CI -15 to -2%, p = 0.011). Adherence to postoperative phase interventions had the greatest impact on recovery (OR 1.29, 95%CI 1.13-1.47 for every additional postoperative element; p < 0.001). At multivariable regression, early termination of IV fluids was the only ERP element associated with successful recovery (OR 2.80, 95%CI 1.73-4.54; p < 0.001). CONCLUSION: Increased adherence to ERP elements was associated with successful early recovery and reduction of postoperative complication severity.

Tracheoesophageal Fistula in a COVID-19 Ventilated Patient: A Challenging Therapeutic Decision.

COVID-19 associated severe respiratory failure frequently requires admission to an intensive care unit, tracheal intubation, and mechanical ventilation. Among the risks of prolonged mechanical ventilation under these conditions, there is the development of tracheoesophageal fistula. We describe a case of a severe COVID-19 associated respiratory failure, who developed a tracheoesophageal fistula. We hypothesized that one of the mechanisms for tracheoesophageal fistula, along with other local and general risk factors, is the local infection due to the location of the virus itself in the tracheobronchial tree. The patient was managed successfully with surgical intervention. This case highlights the increased risk of this potentially life-threatening complication among the COVID-19 patient cohort and suggests a management strategy.

COVID-19 cognitive deficits after respiratory assistance in the subacute phase: A COVID-rehabilitation unit experience.

INTRODUCTION: COVID-19 complications can include neurological, psychiatric, psychological, and psychosocial impairments. Little is known on the consequences of SARS-COV-2 on cognitive functions of patients in the sub-acute phase of the disease. We aimed to investigate the impact of COVID-19 on cognitive functions of patients admitted to the COVID-19 Rehabilitation Unit of the San Raffaele Hospital (Milan, Italy). MATERIAL AND METHODS: 87 patients admitted to the COVID-19 Rehabilitation Unit from March 27th to June 20th 2020 were included. Patients underwent Mini Mental State Evaluation (MMSE), Montreal Cognitive Assessment (MoCA), Hamilton Rating Scale for Depression, and Functional Independence Measure (FIM). Data were divided in 4 groups according to the respiratory assistance in the acute phase: Group1 (orotracheal intubation), Group2 (non-invasive ventilation using Biphasic Positive Airway Pressure), Group3 (Venturi Masks), Group4 (no oxygen therapy). Follow-ups were performed at one month after home-discharge. RESULTS: Out of the 87 patients (62 Male, mean age 67.23 ± 12.89 years), 80% had neuropsychological deficits (MoCA and MMSE) and 40% showed mild-to-moderate depression. Group1 had higher scores than Group3 for visuospatial/executive functions (p = 0.016), naming (p = 0.024), short- and long-term memory (p = 0.010, p = 0.005), abstraction (p = 0.024), and orientation (p = 0.034). Group1 was younger than Groups2 and 3. Cognitive impairments correlated with patients' age. Only 18 patients presented with anosmia. Their data did not differ from the other patients. FIM (<100) did not differ between groups. Patients partly recovered at one-month follow-up and 43% showed signs of post-traumatic stress disorder. CONCLUSION: Patients with severe functional impairments had important cognitive and emotional deficits which might have been influenced by the choice of ventilatory therapy, but mostly appeared to be related to aging, independently of FIM scores. These findings should be integrated for correct neuropsychiatric assistance of COVID-19 patients in the subacute phase of the disease, and show the need for long-term psychological support and treatment of post-COVID-19 patients.

Procedural sedation and analgesia for percutaneous high-tech cardiac procedures.

The interest in percutaneous high-tech cardiac procedures has increased in recent years together with its safety and efficacy. In fragile patients, procedural sedation and analgesia are used to perform most of the procedures. General anesthesia remains the technique of choice during the team learning curve and might be required in selected patients or in emergent situations. Despite the high costs of percutaneous high-tech cardiac procedures, the decrease in length of hospital stays, rate of intensive care admission and complications, balance the increase in devices costs. In fragile patients who undergo percutaneous high tech cardiac procedures, the primary role of the anesthesiologist is to prevent the need for postprocedural intensive care unit and complications rate. Starting from the experience of a large university third level hospital we identified the eight most commonly performed contemporary percutaneous high tech cardiac procedures (ventricular tachycardia and atrial fibrillation ablation, protected percutaneous coronary intervention, transcatheter aortic valve implantation, MitraClip® (Abbott Laboratories; Abbott Park, IL, USA), percutaneous patent foramen ovale closure, left atrial appendage closure, and dysfunctional lead extraction), discuss the role of procedural sedation and analgesia in this setting, and explore future perspectives.

Prevalence, Characteristics, Risk Factors, and Outcomes of Invasively Ventilated COVID-19 Patients with Acute Kidney Injury and Renal Replacement Therapy.

BACKGROUND: There is no information on acute kidney injury (AKI) and continuous renal replacement therapy (CRRT) among invasively ventilated coronavirus disease 2019 (COVID-19) patients in Western healthcare systems. OBJECTIVE: To study the prevalence, characteristics, risk factors and outcome of AKI and CRRT among invasively ventilated COVID-19 patients. METHODS: Observational study in a tertiary care hospital in Milan, Italy. RESULTS: Among 99 patients, 72 (75.0%) developed AKI and 17 (17.7%) received CRRT. Most of the patients developed stage 1 AKI (33 [45.8%]), while 15 (20.8%) developed stage 2 AKI and 24 (33.4%) a stage 3 AKI. Patients who developed AKI or needed CRRT at latest follow-up were older, and among CRRT treated patients a greater proportion had preexisting CKD. Hospital mortality was 38.9% for AKI and 52.9% for CRRT patients. CONCLUSIONS: Among invasively ventilated COVID-19 patients, AKI is very common and CRRT use is common. Both carry a high risk of in-hospital mortality.

Characteristics, treatment, outcomes and cause of death of invasively ventilated patients with COVID-19 ARDS in Milan, Italy.

OBJECTIVE: Describe characteristics, daily care and outcomes of patients with coronavirus disease 2019 (COVID-19) acute respiratory distress syndrome (ARDS). DESIGN: Case series of 73 patients. SETTING: Large tertiary hospital in Milan. PARTICIPANTS: Mechanically ventilated patients with confirmed COVID-19 admitted to the intensive care unit (ICU) between 20 February and 2 April 2020. MAIN OUTCOME MEASURES: Demographic and daily clinical data were collected to identify predictors of early mortality. RESULTS: Of the 73 patients included in the study, most were male (83.6%), the median age was 61 years (interquartile range [IQR], 54-69 years), and hypertension affected 52.9% of patients. Lymphocytopenia (median, 0.77 x 103 per mm3; IQR, 0.58-1.00 x 103 per mm3), hyperinflammation with C-reactive protein (median, 184.5 mg/dL; IQR, 108.2-269.1 mg/dL) and pro-coagulant status with D-dimer (median, 10.1 µg/m; IQR, 5.0-23.8 µg/m) were present. Median tidal volume was 6.7 mL/kg (IQR, 6.0-7.5 mL/kg), and median positive end-expiratory pressure was 12 cmH2O (IQR, 10-14 cmH2O). In the first 3 days, prone positioning (12-16 h) was used in 63.8% of patients and extracorporeal membrane oxygenation in five patients (6.8%). After a median follow-up of 19.0 days (IQR, 15.0-27.0 days), 17 patients (23.3%) had died, 23 (31.5%) had been discharged from the ICU, and 33 (45.2%) were receiving invasive mechanical ventilation in the ICU. Older age (odds ratio [OR], 1.12; 95% CI, 1.04-1.22; P = 0.004) and hypertension (OR, 6.15; 95% CI, 1.75-29.11; P = 0.009) were associated with mortality, while early improvement in arterial partial pressure of oxygen (PaO2) to fraction of inspired oxygen (FiO2) ratio was associated with being discharged alive from the ICU (P = 0.002 for interaction). CONCLUSIONS: Despite multiple advanced critical care interventions, COVID-19 ARDS was associated with prolonged ventilation and high short term mortality. Older age and pre-admission hypertension were key mortality risk factors. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT04318366.

Early predictors of clinical outcomes of COVID-19 outbreak in Milan, Italy.

BACKGROUND: National health-system hospitals of Lombardy faced a heavy burden of admissions for acute respiratory distress syndromes associated with coronavirus disease (COVID-19). Data on patients of European origin affected by COVID-19 are limited. METHODS: All consecutive patients aged ≥18 years, coming from North-East of Milan's province and admitted at San Raffaele Hospital with COVID-19, between February 25th and March 24th, were reported, all patients were followed for at least one month. Clinical and radiological features at admission and predictors of clinical outcomes were evaluated. RESULTS: Of the 500 patients admitted to the Emergency Unit, 410 patients were hospitalized and analyzed: median age was 65 (IQR 56-75) years, and the majority of patients were males (72.9%). Median (IQR) days from COVID-19 symptoms onset was 8 (5-11) days. At hospital admission, fever (≥ 37.5 °C) was present in 67.5% of patients. Median oxygen saturation (SpO2) was 93% (range 60-99), with median PaO2/FiO2 ratio, 267 (IQR 184-314). Median Radiographic Assessment of Lung Edema (RALE) score was 9 (IQR 4-16). More than half of the patients (56.3%) had comorbidities, with hypertension, coronary heart disease, diabetes and chronic kidney failure being the most common. The probability of overall survival at day 28 was 66%. Multivariable analysis showed older age, coronary artery disease, cancer, low lymphocyte count and high RALE score as factors independently associated with an increased risk of mortality. CONCLUSION: In a large cohort of COVID-19 patients of European origin, main risk factors for mortality were older age, comorbidities, low lymphocyte count and high RALE.

Microvascular COVID-19 lung vessels obstructive thromboinflammatory syndrome (MicroCLOTS): an atypical acute respiratory distress syndrome working hypothesis.

We suggest the use of MicroCLOTS (microvascular COVID-19 lung vessels obstructive thromboinflammatory syndrome) as a new name for severe pulmonary coronavirus disease 2019 (COVID-19). We hypothesise that, in predisposed individuals, alveolar viral damage is followed by an inflammatory reaction and by microvascular pulmonary thrombosis. This progressive endothelial thromboinflammatory syndrome may also involve the microvascular bed of the brain and other vital organs, leading to multiple organ failure and death. Future steps in the understanding of the disease and in the identification of treatments may benefit from this definition and hypothesised sequence of events.

Fast reshaping of intensive care unit facilities in a large metropolitan hospital in Milan, Italy: facing the COVID-19 pandemic emergency

At the end of 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak spread from China all around the world, causing thousands of deaths. In Italy, the hardest hit region was Lombardy, with the first reported case on 20 February 2020. San Raffaele Scientific Institute ­ a large tertiary hospital and research centre in Milan, Italy ­ was immediately involved in the management of the public health emergency. Since the beginning of the outbreak, the elective surgical activity of the hospital was rapidly reduced and large areas of the hospital were simultaneously reorganised to admit and assist patients with coronavirus disease 2019 (COVID-19). In addition, the hospital became the regional referral hub for cardiovascular emergencies in order to keep ensuring a high level of health care to non-COVID-19 patients in northern Italy. In a few days, a COVID-19 emergency department was created, improving the general ward capacity to a total number of 279 beds dedicated to patients with COVID-19. Moreover, the number of intensive care unit (ICU) beds was increased from 28 to 72 (54 of them dedicated to patients with COVID-19, and 18 to cardiology and cardiac surgery hub emergencies), both converting pre-existing areas and creating new high technology spaces. All the involved health care personnel were rapidly trained to use personal protection equipment and to manage this particular category of patients both in general wards and ICUs. Furthermore, besides clinical activities, continuously important research projects were carried out in order to find new strategies and more effective therapies to better face an unprecedented health emergency in Italy.

Pre-operative transnasal endoscopy as a predictor of difficult airway: A prospective cohort study.

BACKGROUND: Consequences of failed endotracheal intubation can be catastrophic and predicting difficulty is therefore a critical issue. There is no consensus on the best way to predict difficulty. OBJECTIVE: To evaluate the role of transnasal flexible endoscopic laryngoscopy (TFEL), a minimally invasive procedure, in the prediction of difficult intubation. DESIGN: Prospective cohort study. SETTING: San Raffaele Hospital, Milan, a tertiary university hospital. PATIENTS: One hundred and sixty nine adults scheduled for elective ear, nose and throat surgery under general anaesthesia with pre-operative TFEL. INTERVENTION: In addition to routine pre-operative evaluation by an anaesthesiologist, glottis exposure during TFEL was assessed with a scoring system similar to the modified Cormack-Lehane (MCL). MAIN OUTCOME MEASURES: The extent to which TFEL improves the prediction of difficult direct laryngoscopy, measured with the MCL score, and of difficult intubation, measured with the intubation difficulty scale score. RESULTS: When added to bedside evaluation, TFEL performed during tongue protrusion significantly (P = 0.005) improved the prediction of MCL. The area under the receiver operating characteristics curve was 0.75 [95% confidence interval (CI) 0.67 to 0.83] vs. 0.65 (95% CI 0.58 to 0.74). For the intubation difficulty scale (P = 0.049), the area under the receiver operating characteristics curve was 0.70 (95% CI 0.61 to 0.80) vs. 0.66 (95% CI 0.58 to 0.74). CONCLUSION: TFEL is a useful tool in predicting difficult intubation, improving predictability of routine bedside evaluation. TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT02671877.