Given a passage, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.

Example Input: To compare the safety and success of a retrograde approach using a microcatheter vs. a sheath in the treatment of superficial femoral artery (SFA) chronic total occlusions (CTOs).', 'From April 2007 to December 2012, 188 consecutive patients underwent EVT for 229 de novo SFA CTOs using the retrograde approach in 68 patients (35 men; mean age 72 years). This cohort was divided into cases performed with a 4-F or 6-F sheath (n=28, 36 limbs) and those with a 2.1-F microcatheter (n=35, 49 limbs). The primary outcomes were mean time to hemostasis and number of intra- and postoperative puncture site complications, as well as the success of popliteal artery puncture, lesion crossing, and reperfusion.', 'There were no significant differences between two groups in baseline characteristics. PA puncture was successful in all limbs, and the success in crossing the lesion with the wire was not significantly different (91.9% in the sheath group vs. 89.8% in the microcatheter group). Mean time to hemostasis was 8.9±8.8 minutes in the microcatheter group vs. 47.7±13 minutes in the sheath group (p<0.0001). There was a significant difference in intraoperative and postoperative complications (22.2% in the sheath group vs. 2.0% in the microcatheter group, p=0.002).
Example Output: Is a sheathless retrograde approach via the popliteal artery useful and safe for treating chronic total occlusions in the superficial femoral artery?

Example Input: Extranodal natural killer/T-cell lymphoma, nasal type (ENKTL), is an aggressive type of lymphoma whose standard treatment and validated prognostic model have not yet been defined.', 'CD30 expression was detected using immunohistochemistry in 96 ENKTL patients, and the data were used to evaluate its relationship with clinical features, treatment response and prognosis.', 'Expression of CD30 was detected in 31.2% of ENKTL patients, which was significantly correlated with B symptoms and elevated serum lactate dehydrogenase. The complete remission rate was not significantly different between CD30-positive and negative groups. After a median follow-up time of 31 months, 5-year overall survival (OS) and 5-year progression-free survival (PFS) rates in the CD30-positive group were both significantly lower than those in the CD30-negative group (34.1% vs. 64.4%, P=0.002, for 5 year-OS; 26.0% vs. 66.7%, P<0.001, for 5 year-PFS). In patients with an International Prognostic Index (IPI) or Korean Prognostic Index (KPI) score of 0-1, CD30 positivity was associated with shorter 5-year OS and PFS (IPI: P=0.001 and 0.002, respectively; KPI: P=0.018 and 0.023, respectively). In a multivariate Cox regression model, CD30 expression and stage were independent prognostic factors for OS (p=0.004 and p=0.012, respectively) and PFS (p=0.001 and p=0.022, respectively).
Example Output: Is cD30 expression a novel prognostic indicator in extranodal natural killer/T-cell lymphoma , nasal type?

Example Input: The efficacy of programmes to reduce long-term benzodiazepine use could be compromised by subsequent increases in contacts with the family practice. In this study the hypothesis was tested as to whether participation in a benzodiazepine discontinuation programme affects the frequency of contacts with the family practice.', 'A controlled stepped-care intervention programme to decrease long-term benzodiazepine use.', 'Family practices in the Netherlands. Subjects. The experimental group consisted of 996 long-term benzodiazepine users and a control group of 883 long-term benzodiazepine users.', 'Practice contacts before and up to 12 months after the start of the programme.', 'There was a general tendency visible for contacts to decrease during the follow-up time. The course of the number of contacts during the follow-up was not different for the experimental and control groups (p=0.45). The level of non-benzodiazepine prescriptions was generally not altered. The number of non-benzodiazepine prescriptions decreased in benzodiazepine quitters during the follow-up of the programme.
Example Output:
Does a benzodiazepine discontinuation programme increase the frequency of contacts with the family practice?