James R. Edgerton M.D.

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.

Filardo, G., B. D. Pollock and J. Edgerton (2017). “Categorizing body mass index biases assessment of the association with post-coronary artery bypass graft mortality.” Eur J Cardiothorac Surg: 2017 May [Epub ahead of print].

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OBJECTIVES: The high prevalence of obesity makes accurately estimating the impact of anthropometric measures on cardiac surgery outcomes critical. The Society of Thoracic Surgeons coronary artery bypass graft (CABG) surgery risk model includes body surface area (as a continuous variable, using spline functions), but most studies apply various categorizations of body mass index (BMI)-contributing to the contradictory published findings. We assessed the association between BMI (modelled as a continuous variable without assumptions of linearity) and CABG operative mortality and examined the impact of applying previous studies’ BMI modelling strategies. METHODS: We identified 25 studies investigating the BMI-operative mortality association: 22 categorized BMI, 2 as a linear continuous variable,1 used spline functions. Our cohort of 12 715 consecutive patients underwent isolated CABG at 32 cardiac surgery programmes in North Texas from 1 January 2008-31 December 2012. BMI was modelled using restricted cubic spline functions in a propensity-adjusted model (controlling for Society of Thoracic Surgeons risk factors) estimating operative mortality. The analysis was repeated using each categorization identified and modelling BMI as a linear continuous variable. RESULTS: BMI (modelled with a restricted cubic spline) was significantly associated with operative mortality ( P < 0.0001). Risk was lowest for BMI near 30 kg/m 2 and highest below 20 kg/m 2 and above 40 kg/m 2 . No categorization, nor the linear continuous model, fully captured this association. CONCLUSIONS: BMI is strongly associated with CABG operative mortality. Categorizing BMI (or assuming a linear relationship) heavily biases estimates of its association with post-CABG mortality. In general, smoothing techniques should be used for all continuous risk factors to avoid bias.

Edgerton, J. R. (2017). “Tick tock. Tick tock. Tic-tic-tic-tic: If you watch the pot long enough, it boils.” J Thorac Cardiovasc Surg 153(5): 1095-1096.

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In this issue of the Journal, Damiano and colleagues1 provide 5-year results of surgical ablation (SA) concomitant to coronary artery bypass grafting (CABG). Given the problems associated with following referral patients over 5 years, this is a laudable effort. In surgical and catheter ablation literature filled with glowing 1-year results, this type of long-term follow-up, reported according to the 2012 Consensus Statement,2 is sorely needed. And the results are sobering: 70% of patients were free of atrial tachyarrhythmias and off antiarrhythmic drugs at 5 years. These results are similar to a previously reported larger group of 512 patients who had a 66% similar outcome.3 These papers, in the modern reporting era of continuous rhythm monitoring, contrast with their 2003 report of 98% freedom from AF at 5 years in patients undergoing CABG/maze.4…Despite these things, we need to be aggressively treating our operative patients who have AF.

Badhwar, V., J. S. Rankin, R. J. Damiano, Jr., A. M. Gillinov, F. G. Bakaeen, J. R. Edgerton, J. M. Philpott, P. M. McCarthy, S. F. Bolling, H. G. Roberts, V. H. Thourani, R. M. Suri, R. J. Shemin, S. Firestone and N. Ad (2017). “The society of thoracic surgeons 2017 clinical practice guidelines for the surgical treatment of atrial fibrillation.” Ann Thorac Surg 103(1): 329-341.

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EXECUTIVE SUMMARY: Surgical ablation for atrial fibrillation (AF) can be performed without additional risk of operative mortality or major morbidity, and is recommended at the time of concomitant mitral operations to restore sinus rhythm. (Class I, Level A) Surgical ablation for AF can be performed without additional operative risk of mortality or major morbidity, and is recommended at the time of concomitant isolated aortic valve replacement, isolated coronary artery bypass graft surgery, and aortic valve replacement plus coronary artery bypass graft operations to restore sinus rhythm. (Class I, Level B nonrandomized) Surgical ablation for symptomatic AF in the absence of structural heart disease that is refractory to class I/III antiarrhythmic drugs or catheter-based therapy or both is reasonable as a primary stand-alone procedure, to restore sinus rhythm. (Class IIA, Level B randomized) Surgical ablation for symptomatic persistent or longstanding persistent AF in the absence of structural heart disease is reasonable, as a stand-alone procedure using the Cox-Maze III/IV lesion set compared with pulmonary vein isolation alone. (Class IIA, Level B nonrandomized) Surgical ablation for symptomatic AF in the setting of left atrial enlargement (>/=4.5 cm) or more than moderate mitral regurgitation by pulmonary vein isolation alone is not recommended. (Class III no benefit, Level C expert opinion) It is reasonable to perform left atrial appendage excision or exclusion in conjunction with surgical ablation for AF for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C limited data) At the time of concomitant cardiac operations in patients with AF, it is reasonable to surgically manage the left atrial appendage for longitudinal thromboembolic morbidity prevention. (Class IIA, Level C expert opinion) In the treatment of AF, multidisciplinary heart team assessment, treatment planning, and long-term follow-up can be useful and beneficial to optimize patient outcomes.