Research Spotlight

Posted December 15th 2017

Potential of predictive computer models for preoperative patient selection to enhance overall quality-adjusted life years gained at 2-year follow-up: a simulation in 234 patients with adult spinal deformity.

Richard Hostin M.D.

Richard Hostin M.D.

Oh, T., J. K. Scheer, J. S. Smith, R. Hostin, C. Robinson, J. L. Gum, F. Schwab, R. A. Hart, V. Lafage, D. C. Burton, S. Bess, T. Protopsaltis, E. O. Klineberg, C. I. Shaffrey and C. P. Ames (2017). “Potential of predictive computer models for preoperative patient selection to enhance overall quality-adjusted life years gained at 2-year follow-up: A simulation in 234 patients with adult spinal deformity.” Neurosurg Focus 43(6): 2017 Nov [Epub ahead of print].

Full text of this article.

OBJECTIVE Patients with adult spinal deformity (ASD) experience significant quality of life improvements after surgery. Treatment, however, is expensive and complication rates are high. Predictive analytics has the potential to use many variables to make accurate predictions in large data sets. A validated minimum clinically important difference (MCID) model has the potential to assist in patient selection, thereby improving outcomes and, potentially, cost-effectiveness. METHODS The present study was a retrospective analysis of a multiinstitutional database of patients with ASD. Inclusion criteria were as follows: age >/= 18 years, radiographic evidence of ASD, 2-year follow-up, and preoperative Oswestry Disability Index (ODI) > 15. Forty-six variables were used for model training: demographic data, radiographic parameters, surgical variables, and results on the health-related quality of life questionnaire. Patients were grouped as reaching a 2-year ODI MCID (+MCID) or not (-MCID). An ensemble of 5 different bootstrapped decision trees was constructed using the C5.0 algorithm. Internal validation was performed via 70:30 data split for training/testing. Model accuracy and area under the curve (AUC) were calculated. The mean quality-adjusted life years (QALYs) and QALYs gained at 2 years were calculated and discounted at 3.5% per year. The QALYs were compared between patients in the +MCID and -MCID groups. RESULTS A total of 234 patients met inclusion criteria (+MCID 129, -MCID 105). Sixty-nine patients (29.5%) were included for model testing. Predicted versus actual results were 50 versus 40 for +MCID and 19 versus 29 for -MCID (i.e., 10 patients were misclassified). Model accuracy was 85.5%, with 0.96 AUC. Predicted results showed that patients in the +MCID group had significantly greater 2-year mean QALYs (p = 0.0057) and QALYs gained (p = 0.0002). CONCLUSIONS A successful model with 85.5% accuracy and 0.96 AUC was constructed to predict which patients would reach ODI MCID. The patients in the +MCID group had significantly higher mean 2-year QALYs and QALYs gained. This study provides proof of concept for using predictive modeling techniques to optimize patient selection in complex spine surgery.


Posted December 15th 2017

Kinetics of Urinary Cell Cycle Arrest Markers for Acute Kidney Injury Following Exposure to Potential Renal Insults.

Peter McCullough M.D.

Peter McCullough M.D.

Ostermann, M., P. A. McCullough, L. G. Forni, S. M. Bagshaw, M. Joannidis, J. Shi, K. Kashani, P. M. Honore, L. S. Chawla and J. A. Kellum (2017). “Kinetics of urinary cell cycle arrest markers for acute kidney injury following exposure to potential renal insults.” Crit Care Med: 2017 Nov [Epub ahead of print].

Full text of this article.

OBJECTIVES: Urinary tissue inhibitor of metalloproteinase-2 and insulin-like growth factor binding protein 7 predict the development of acute kidney injury following renal insults of varied aetiology. To aid clinical interpretation, we describe the kinetics of biomarker elevations around an exposure. DESIGN: In an ancillary analysis of the multicenter SAPPHIRE study, we examined the kinetics of the urinary [tissue inhibitor of metalloproteinase-2]*[insulin-like growth factor binding protein 7] in association with exposure to common renal insults (major surgery, IV radiocontrast, vancomycin, nonsteroidal anti-inflammatory drugs, and piperacillin/tazobactam). SETTING: Thirty-five sites in North America and Europe between September 2010 and June 2012. PATIENTS: Seven hundred twenty-three critically ill adult patients admitted to the ICU. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: We compared the urinary [tissue metalloproteinase-2]*[insulin growth factor binding protein 7] kinetics from the day prior to exposure up to 5 days after exposure in patients developing acute kidney injury stage 2-3, stage 1, or no acute kidney injury by Kidney Disease Improving Global Outcome criteria. Among the 723 patients, 679 (94%) had at least one, 70% had more than one, and 35% had three or more exposures to a known renal insult. There was a significant association between cumulative number of exposures up to study day 3 and risk of acute kidney injury (p = 0.02) but no association between the specific type of exposure and acute kidney injury (p = 0.22). With the exception of radiocontrast, patients who developed acute kidney injury stage 2-3 after one of the five exposures, had a clear rise and fall of urinary [tissue inhibitor of metalloproteinase-2]*[insulin-like growth factor binding protein 7] from the day of exposure to 24-48 hours later. In patients without acute kidney injury, there was no significant elevation in urinary [tissue inhibitor of metalloproteinase-2]*[insulin-like growth factor binding protein 7]. CONCLUSIONS: Exposure to potential renal insults is common. In patients developing acute kidney injury stage 2-3, the kinetics of urinary [tissue inhibitor of metalloproteinase-2]*[insulin-like growth factor binding protein 7] matched the exposure except in the case of radiocontrast.


Posted December 15th 2017

Variations in Outcomes of Emergency General Surgery Patients Across Hospitals: A Call to Establish Emergency General Surgery Quality Improvement Program (EQIP).

Shahid Shafi M.D.

Shahid Shafi M.D.

Ogola, G. O., M. L. Crandall and S. Shafi (2017). “Variations in outcomes of emergency general surgery patients across hospitals: A call to establish emergency general surgery quality improvement program (eqip).” J Trauma Acute Care Surg: 2017 Nov [Epub ahead of print].

Full text of this article.

BACKGROUND: National Surgical Quality Improvement Program (NSQIP) and Trauma Quality Improvement Program (TQIP) have shown variations in risk-adjusted outcomes across hospitals. Our study hypothesis was that there would be similar variation in risk-adjusted outcomes of Emergency General Surgery (EGS) patients. METHODS: We undertook a retrospective analysis of the National Inpatient Sample database for 2010. Patients with EGS diseases were identified using American Association for the Surgery of Trauma definitions. A hierarchical logistic regression model was used to model in-hospital mortality, accounting for patient characteristics, including age, sex, race, ethnicity, insurance type, and comorbidities. Predicted-to-Expected mortality ratios with 90% confidence intervals, were used to identify hospitals as low mortality (ratio significantly lower than 1), high mortality (ratio significantly higher than 1), or average mortality (ratio overlapping 1). RESULTS: Nationwide, 2,640,725 patients with EGS diseases were treated at 943 hospitals in 2010. About one-sixth of the hospitals (139, 15%) were low mortality, a quarter were high mortality (221, 23%), while the rest were average mortality. Mortality ratio at low mortality hospitals was almost four times lower than that of high mortality hospitals (0.57 vs. 2.03, p < .0001). If high and average mortality hospitals performed at the same level as low mortality hospitals, we estimate 16,812 (55%) more deaths than expected. CONCLUSION: There are significant variations in risk-adjusted outcomes of EGS patients across hospitals, with several thousand higher than expected number of deaths nationwide. Based upon the success of NSQIP and TQIP, we recommend establishing EGS Quality Improvement Program (EQIP) for risk-adjusted benchmarking of hospitals for EGS patients.


Posted December 15th 2017

Are Meta-Analyses a Form of Medical Fake News? Thoughts About How They Should Contribute to Medical Science and Practice.

Milton Packer M.D.

Milton Packer M.D.

Packer, M. (2017). “Are meta-analyses a form of medical fake news? Thoughts about how they should contribute to medical science and practice.” Circulation 136(22): 2097-2099.

Full text of this article.

Many physicians believe (incorrectly) that there is something magical about a metaanalysis. A meta-analysis is an observational study, but the author does no original work. Someone simply notices that several articles have data that pertain to a common topic and that they might show similar patterns. How can the patterns be described? In the past, the favored approach was to depict these in a narrative, but this task required insight into the details of each trial and a willingness to ask whether differences in design or execution might have contributed to differences in a study’s findings. The current approach to meta-analysis requires no such intellectual effort; little knowledge is needed about any trial, except that it possesses certain minimum features. Advocates of meta-analyses claim that they select trials for inclusion or exclusion based solely on their methodological qualities without awareness of their results, but it is difficult to understand how that could happen. Can the author of a meta-analysis claim to have read only the methods section of an article, but ignored the title, abstract, results, and discussion?


Posted December 15th 2017

Microcatheter balloon pinning technique to facilitate wiring of a left circumflex chronic total occlusion.

James W. Choi M.D.

James W. Choi M.D.

Oguayo, K. N., C. C. Oguayo, R. Vallabhan and J. W. Choi (2017). “Microcatheter balloon pinning technique to facilitate wiring of a left circumflex chronic total occlusion.” Cardiovasc Ther 35(6): 2017 Nov [Epub ahead of print].

Full text of this article.

INTRODUCTION: Coronary chronic total occlusions (CTOs) are commonly encountered during diagnostic angiograms. With recent advances, especially in experienced centers, success rates with CTO percutaneous coronary intervention (PCI) have approached 80% or higher. It is important to note that despite these advancements in techniques, CTOs remain difficult to treat. We present a case of a left circumflex artery (LCX) CTO that was successfully revascularized using a microcatheter balloon pinning technique that allowed additional wire support. CASE REPORT: A 77-year-old woman status post-two-vessel coronary artery bypass graft surgery presented with new onset angina at rest and was found to have a patent graft to the left anterior descending artery, and an unrevascularized proximal LCX CTO. PCI was attempted with a microcatheter using an antegrade approach. This approach was unsuccessful due to the lack of support and the left circumflex angle. As a result, we used a balloon to pin the microcatheter to the wall of the left main to allow for successful wiring of the LCX. A stent was successfully deployed in the LCX, and the patient was discharged from the hospital 2 days later. At follow-up, the patient was asymptomatic and returned to her usual activity. DISCUSSION: After conducting a thorough literature search, it appears that this is the first case that a microcatheter has been pinned with a balloon. We believe that in LCX CTOs that require support, the microcatheter pinning technique can provide adequate support in wiring CTO’s. LCX CTOs can be very difficult to treat, we present a case of a LCX CTO that required the use of the microcatheter balloon pinning technique to allow additional wire support for successful wiring and ultimately treatment.