Given a passage with a context and an answer, 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.

Input: Consider Input: Context: Noninvasive pacemaker stress echocardiography is a newly introduced method for the diagnosis of coronary artery disease in patients with a permanent pacemaker. The prognostic value of pacemaker stress echocardiography has not been studied.', 'We studied 136 patients (mean age 64+/-12 years) with a permanent pacemaker who underwent pacemaker stress echocardiography for evaluation of coronary artery disease. All patients underwent pacemaker stress echocardiography by external programming (pacing heart rate up to ischemia or target heart rate).', 'Thirty-one patients (23%) had normal study results. Ischemia was detected in 75 patients (55%). During a mean follow-up of 3.5+/-2.4 years, 35 deaths (26%) (20 the result of cardiac causes) and 2 nonfatal myocardial infarctions (1%) occurred. The annual cardiac death rate was 1.3% in patients without ischemia and 4.6% in patients with ischemia (P=.01). The annual all-cause mortality rate was 3.1% in patients without ischemia and 7% in patients with ischemia (P=.004). The presence of ischemia during pacemaker stress echocardiography was the strongest independent predictor of cardiac death (hazard ratio 4.1, confidence interval 1.2-14.5) and all-cause mortality (hazard ratio 2.7, confidence interval 1.2-6.0) in a multivariable model.
Answer: Myocardial ischemia during pacemaker stress echocardiography is an independent predictor of cardiac death and all-cause mortality in patients with a permanent pacemaker.

Output: Does pacemaker stress echocardiography predict cardiac events in patients with permanent pacemaker?


Input: Consider Input: Context: Central giant cell lesion (CGCL) and giant cell tumour (GCT) are bone lesions that share similar microscopic features. Recently, it was reported that 90% of bone GCT exhibit either p.Gly34 Trp or p.Gly34 Leu in H3F3A, one of two genes for histone H3.3 located on chromosome 1. We aimed to test whether sporadic CGCL of the jaws share the H3F3A mutations reported in GCT of other bones.', 'Nine samples of CGCL of the jaws were included in the study, and mutations were assessed by direct sequencing.', 'None of the CGCL samples presented the recurrent p.Gly34 Trp or p.Gly34 Leu mutations in the H3F3A gene.
Answer: On the basis of our findings, H3F3A p.Gly34 Trp or p.Gly34 Leu mutations are not a frequent event in CGCL. If these alterations are confirmed to be exclusive of GCT, the assessment of H3F3A mutations may help in the differential diagnosis of GCT and CGCL of the jaws.

Output: Is the highly prevalent H3F3A mutation in giant cell tumours of bone shared by sporadic central giant cell lesion of the jaws?


Input: Consider Input: Context: Retrospective cohort study.', 'To compare short-term morbidity for primary and revision posterior lumbar fusions.', 'Revision lumbar fusions are unfortunately relatively common. Previous studies have described an increased risk of postoperative complications after revision lumbar fusion; however, these studies have been limited by small sample sizes, poor data quality, and/or narrow outcome measures. There is a need to validate these findings using a high-quality, national cohort of patients to have an accurate assessment of the relative risk of revision posterior lumbar fusions compared with primary lumbar fusion.', 'The prospectively-collected American College of Surgeons National Surgical Quality Improvement Program database was used to identify patients that underwent undergoing primary and revision posterior lumbar fusion from 2005 to 2013. The occurrence of individual and aggregated postoperative complications within 30 days, along with rates of blood transfusion and readmission, were compared between primary and revision procedures using bivariate and multivariate Poisson regression with robust error variance to control for patient and operative characteristics. Operative time and postoperative length of stay were compared between groups using bivariate and multivariate linear regression.', 'Of the 14,873 posterior lumbar fusion procedures that met inclusion criteria, 1287 (8.7%) were revision cases. There were no differences in the rates of 30-day postoperative complications or readmission between primary and revision posterior lumbar fusion using multivariate analysis to control for patient and operative characteristics. Similarly, no significant differences were found for operative time or postoperative length of stay. There was an increased rate of blood transfusion for revision surgery compared with primary surgery (relative risk 1.4, P\u200a<\u200a0.001).
Answer: This study suggests that revision posterior lumbar fusion does not carry significantly increased risk of complications or readmission compared with a primary posterior lumbar fusion. Patients undergoing revision surgery were more likely to receive a blood transfusion. This information suggests that general health risk stratification for revision procedures can be similar to that considered for primary cases.


Output: Do primary and Revision Posterior Lumbar Fusion Have Similar Short-Term Complication Rates?