Research Spotlight

Goldberg, R. J. and H. L. Nguyen (2017). “Unlocking the keys to site activation and recruitment success in a randomized controlled trial.” Stroke 48(9): 2339-2340.

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Two of the most crucial requirements for successfully carrying out and completing an RCT are the initial construction of different hypothetical scenarios to determine how many healthy individuals or patients with a specific disease or condition are needed to be enrolled in the trial and eventually followed on either a short- or long-term basis to find clinically meaningful differences in one’s principal study outcomes and, subsequently, to go out into the field, find, and recruit a sufficient number of patients to the proposed trial to satisfy one’s predetermined sample size requirements. Moreover, the logistical operations of an RCT need to be performed within the confines of a manageable budget and typically tight timeline for patient enrollment and follow-up in which all too often projected estimates of the number of patients to be enrolled and successfully retained in the trial greatly exceed reality.

Klintmalm, G. B. and B. Kaplan (2017). “The kidney allocation system claims equity;it is time to review utility and fairness.” Am J Transplant: 2017 Aug [Epub ahead of print].

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The current kidney allocation system (KAS) implemented by the United Network for Organ Sharing in December 2014 was intended to balance inequities in kidney allocation while increasing utility by transplanting kidneys expected to last the longest in patients expected to live the longest. In its first iteration, termed Life Years from Transplant (LYFT), a fairly simple system of allocation was proposed to allocate kidneys based on this principle. LYFT, as opposed to our current process, also addressed the need to have a codified system to allocate kidneys unsuitable for younger patients to older recipients, such that utility could be maximized across the spectrum of potential recipients. Due to political pressures, LYFT was not instituted and our current KAS was implemented as a compromise solution (1).

Mooney, J., S. L. Sellers, P. Blanke, P. Pibarot, R. T. Hahn, D. Dvir, P. S. Douglas, N. J. Weissman, S. K. Kodali, V. H. Thourani, H. Jilaihawi, O. Khalique, C. R. Smith, S. H. Kueh, M. Ohana, R. Grover, C. Naoum, A. Crowley, W. A. Jaber, M. C. Alu, R. Parvataneni, M. Mack, J. G. Webb, M. B. Leon and J. A. Leipsic (2017). “Ct-defined prosthesis-patient mismatch downgrades frequency and severity, and demonstrates no association with adverse outcomes after transcatheter aortic valve replacement.” JACC Cardiovasc Interv 10(15): 1578-1587.

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OBJECTIVES: This study sought to determine if indexed effective orifice area (EOAi), using left ventricular outflow tract measured from computed tomography (EOAiCT), reclassified prosthesis-patient mismatch (PPM) compared with conventional echocardiogram-defined measurements (EOAiTTE). BACKGROUND: PPM does not predict mortality following transcatheter aortic valve replacement (TAVR). However, it is unknown if the EOAiCT of the left ventricular outflow tract improves risk stratification. METHODS: A total of 765 TAVR patients from the PARTNER II (Placement of Aortic Transcatheter Valves II) trial S3i cohort were evaluated. EOAi was calculated using the continuity equation, and the left ventricular outflow tract area was derived from baseline computed tomography. Traditional echocardiographic categories defined PPM: absent (>0.85 cm2/m2), moderate (>/=0.65 and

Reilly, C. R., D. V. Babushok, K. Martin, J. L. Spivak, M. Streiff, R. Bahirwani, J. Mondschein, B. Stein, A. Moliterno and E. O. Hexner (2017). “Multicenter analysis of the use of transjugular intrahepatic portosystemic shunt for management of mpn-associated portal hypertension.” Am J Hematol 92(9): 909-914.

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BCR-ABL1-negative myeloproliferative neoplasms (MPNs) are clonal stem cell disorders defined by proliferation of one or more myeloid lineages, and carry an increased risk of vascular events and progression to myelofibrosis and leukemia. Portal hypertension (pHTN) occurs in 7-18% of MPN patients via both thrombotic and nonthrombotic mechanisms and portends a poor prognosis. Transjugular intrahepatic portosystemic shunt (TIPS) has been used in the management of MPN-associated pHTN; however, data on long-term outcomes of TIPS in this setting is limited and the optimal management of medically refractory MPN-associated pHTN is not known. In order to assess the efficacy and long-term outcomes of TIPS in MPN-associated pHTN, we performed a retrospective analysis of 29 MPN patients who underwent TIPS at three academic medical centers between 1997 and 2016. The majority of patients experienced complete clinical resolution of pHTN and its clinical sequelae following TIPS. One, two, three, and four-year overall survival post-TIPS was 96.4%, 92.3%, 84.6%, and 71.4%, respectively. However, despite therapeutic anticoagulation, in-stent thrombosis occurred in 31.0% of patients after TIPS, necessitating additional interventions. In conclusion, TIPS can be an effective intervention for MPN-associated pHTN regardless of etiology. However, TIPS thrombosis is a frequent complication in the MPN population and indefinite anticoagulation post-TIPS should be considered.

Ring, W. S., J. R. Edgerton, M. Herbert, S. Prince, C. Knoff, K. M. Jenkins, M. E. Jessen and B. L. Hamman (2017). “Impact of accurate 30-day status on operative mortality: Wanted dead or alive, not unknown.” Ann Thorac Surg: 2017 Aug [Epub ahead of print].

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BACKGROUND: Risk-adjusted operative mortality is the most important quality metric in cardiac surgery for determining The Society of Thoracic Surgeons (STS) Composite Score for star ratings. Accurate 30-day status is required to determine STS operative mortality. The goal of this study was to determine the effect of unknown or missing 30-day status on risk-adjusted operative mortality in a regional STS Adult Cardiac Surgery Database cooperative and demonstrate the ability to correct these deficiencies by matching with an administrative database. METHODS: STS Adult Cardiac Surgery Database data were submitted by 27 hospitals from five hospital systems to the Texas Quality Initiative (TQI), a regional quality collaborative. TQI data were matched with a regional hospital claims database to resolve unknown 30-day status. The risk-adjusted operative mortality observed-to-expected (O/E) ratio was determined before and after matching to determine the effect of unknown status on the operative mortality O/E. RESULTS: TQI found an excessive (22%) unknown 30-day status for STS isolated coronary artery bypass grafting cases. Matching the TQI data to the administrative claims database reduced the unknowns to 7%. The STS process of imputing unknown 30-day status as alive underestimates the true operative mortality O/E (1.27 before vs 1.30 after match), while excluding unknowns overestimates the operative mortality O/E (1.57 before vs 1.37 after match) for isolated coronary artery bypass grafting. CONCLUSIONS: The current STS algorithm of imputing unknown 30-day status as alive and a strategy of excluding cases with unknown 30-day status both result in erroneous calculation of operative mortality and operative mortality O/E. However, external validation by matching with an administrative database can improve the accuracy of clinical databases such as the STS Adult Cardiac Surgery Database.