Research Spotlight

Thourani, V. H., J. Forcillo, W. Y. Szeto, S. K. Kodali, E. H. Blackstone, A. M. Lowry, M. Semple, J. Rajeswaran, R. R. Makkar, M. R. Williams, J. E. Bavaria, H. C. Herrmann, H. S. Maniar, V. C. Babaliaros, C. R. Smith, A. Trento, P. J. Corso, A. D. Pichard, D. C. Miller, L. G. Svensson, S. Kapadia, G. Ailawadi, R. M. Suri, K. L. Greason, R. T. Hahn, W. A. Jaber, M. C. Alu, M. B. Leon and M. J. Mack (2018). “Outcomes in 937 Intermediate-Risk Patients Undergoing Surgical Aortic Valve Replacement in PARTNER-2A.” Ann Thorac Surg 105(5): 1322-1329.

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BACKGROUND: The Placement of Aortic Transcatheter Valves 2A (PARTNER-2A) randomized trial compared outcomes of transfemoral transcatheter and surgical aortic valve replacement (SAVR) in intermediate-risk patients with severe aortic stenosis. The purpose of the present study was to perform an in-depth analysis of outcomes after SAVR in the PARTNER-2A trial. METHODS: From January 2012 to January 2014, 937 patients underwent SAVR at 57 centers. Mean age was 82 +/- 6.7 years and 55% were men. Less-invasive operations were performed in 140 patients (15%) and concomitant procedures in 198 patients (21%). Major outcomes and echocardiograms were adjudicated by an independent events committee. Follow-up was 94% complete to 2 years. RESULTS: Operative mortality was 4.1% (n = 38, Society of Thoracic Surgeons predicted risk of mortality: 5.2% +/- 2.3%), observed to expected ratio (O/E) was 0.8, and in-hospital stroke was 5.4% (n = 51), twice expected. Aortic clamp and bypass times were 75 +/- 30 minutes and 104 +/- 46 minutes, respectively. Patients having severe prosthesis-patient mismatch (n = 260, 33%) had similar survival to patients without (p > 0.9), as did patients undergoing less-invasive SAVR (p = 0.3). Risk factors for death included cachexia (p = 0.004), tricuspid regurgitation (p = 0.01), coronary artery disease (p = 0.02), preoperative atrial fibrillation (p = 0.001), higher white blood cell count (p < 0.0001), and lower hemoglobin (p = 0.0002). CONCLUSIONS: In this adjudicated prospective study, SAVR in intermediate-risk patients had excellent results at 2 years. However, there were more in-hospital strokes than expected, most likely attributable to mandatory neurologic assessment after the procedure. No pronounced structural valve deterioration was found during 2-year follow-up. Continued long-term surveillance remains important.

Teixeira, P. G. R., C. V. R. Brown, B. Emigh, M. Long, M. Foreman, B. Eastridge, S. Gale, M. S. Truitt, S. Dissanaike, T. Duane, J. Holcomb, A. Eastman and J. Regner (2018). “Civilian Prehospital Tourniquet Use Is Associated with Improved Survival in Patients with Peripheral Vascular Injury.” J Am Coll Surg 226(5): 769-776.e761.

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BACKGROUND: Tourniquet use has been proven to reduce mortality on the battlefield. Although empirically transitioned to the civilian environment, data substantiating survival benefit attributable to civilian tourniquet use is lacking. We hypothesized that civilian prehospital tourniquet use is associated with reduced mortality in patients with peripheral vascular injuries. STUDY DESIGN: We conducted a multicenter retrospective review of all patients sustaining peripheral vascular injuries admitted to 11 Level I trauma centers (January 2011 through December 2016). The study population was divided into 2 groups based on prehospital tourniquet use. Baseline characteristics were compared and factors associated with mortality identified. Logistic regression, adjusting for demographic, physiologic and injury-related parameters, was used to evaluate the association between prehospital tourniquet use and mortality. Delayed amputation was the secondary end point. RESULTS: During 6 years, 1,026 patients with peripheral vascular injuries were admitted. Prehospital tourniquets were used in 181 (17.6%) patients. Tourniquet time averaged 77.3 +/- 63.3 minutes (interquartile range 39.0 to 92.3 minutes). Traumatic amputations occurred in 98 patients (35.7% had a tourniquet). Mortality was 5.2% in the non-tourniquet group compared with 3.9% in the tourniquet group (odds ratio 1.36; 95% CI 0.60 to 1.65; p = 0.452). After multivariable analysis, the use of tourniquets was found to be independently associated with survival (adjusted odds ratio 5.86; 95% CI 1.41 to 24.47; adjusted p = 0.015). Delayed amputation rates were not significantly different between the 2 groups (1.1% vs 1.1%; adjusted odds ratio 1.82; 95% CI 0.36 to 9.99; adjusted p = 0.473). CONCLUSIONS: Although still underused, civilian prehospital tourniquet application was independently associated with a 6-fold mortality reduction in patients with peripheral vascular injuries. More aggressive prehospital application of extremity tourniquets in civilian trauma patients with extremity hemorrhage and traumatic amputation is warranted.

Steimer, D. A., O. Hernandez, D. P. Mason and G. S. Schwartz (2018). “Timing of ECMO Initiation Impacts Survival in Influenza-Associated ARDS.” Thorac Cardiovasc Surg. May 1. [Epub ahead of print].

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In the past decade, extracorporeal membrane oxygenation (ECMO) has emerged as an innovative therapy for influenza-associated acute respiratory distress syndrome (ARDS). Despite its promising results, the ideal timing of ECMO initiation for these patients remains unclear. Retrospective analysis of a single institution experience with venovenous ECMO for influenza-induced ARDS was performed. Twenty-one patients were identified and categorized into early (0-2 days), standard (3-6 days), or late (more than 7 days) cannulation cohorts. Patients cannulated within 48 hours of admission had 80% survival rate at 90 days. Comparatively, the standard and late cannulation cohorts had an observed 90-day survival rate of 60 and 16.7%, respectively.

Spechler, S. J., D. A. Katzka and R. C. Fitzgerald (2018). “New Screening Techniques in Barrett’s Esophagus: Great Ideas or Great Practice?” Gastroenterology 154(6): 1594-1601.

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A number of lines of evidence suggest that Barrett’s metaplasia is a risk factor for esophageal adenocarcinoma (EAC). To prevent deaths from this tumor, medical societies in countries around the world have recommended screening for and surveillance of Barrett’s esophagus. However, the majority of Barrett’s is undiagnosed and compliance with this advice and the adherence to standardized protocols is highly variable among physicians and patients. As a result the impact of screening and surveillance on population-based mortality from this cancer is negligible. Owing to the low incidence of this cancer, compared with cancers such as breast or colon, population-based screening with endoscopy for the purpose of ongoing surveillance has not been recommended except in those with multiple risk factors including a high body mass index, male gender, white race, chronic reflux, and family history. To date, it is not proven that endoscopic screening is beneficial and there are downsides that need to be considered, including the fiscal and psychological costs as well as the possibility of adverse events . . . Does it make sense to use a non-endoscopic screening test in a much larger population than currently recommended to identify even more patients for entry into an endoscopic surveillance program of questionable benefit? Adoption of such a new screening strategy has the potential to succeed where the current strategy has failed to decrease overall deaths from esophageal cancer. However, there also is the potential for harm in identifying asymptomatic patients with Barrett’s esophagus. In addition to the high costs and small risks of standard endoscopy, the diagnosis of Barrett’s esophagus can cause psychological stress, have a negative impact on quality of life, result in higher premiums for health and life insurance, and might identify innocuous lesions that lead to potentially hazardous invasive treatments. Efforts should, therefore, be continued to combined biomarkers for Barrett’s with risk stratification. Overall, although these vexing uncertainties must temper enthusiasm for the unqualified endorsement of any screening test for Barrett’s esophagus, the alternative of making no attempt to stem the rapidly rising incidence of a lethal malignancy also is unpalatable. (Excerpts from text, p. 1594, 1599; no abstract available.)

Spechler, S. J. (2018). “Cardiac Metaplasia: Follow, Treat, or Ignore?” Dig Dis Sci. Apr 18. [Epub ahead of print].

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Over the past two decades, evidence has accumulated to challenge the traditional view that cardiac mucosa, which is comprised exclusively of mucus glands, is the normal lining of the most proximal portion of the stomach (the gastric cardia). There is now considerable evidence to suggest that cardiac mucosa develops as a GERD-induced, squamous-to-columnar esophageal metaplasia in some, if not all, cases. Although cardiac mucosa lacks the goblet cells commonly required for a histologic diagnosis of intestinal metaplasia, cardiac mucosa has many molecular features of an intestinal-type mucosa, and appears to be the precursor of intestinal metaplasia with goblet cells. In apparently normal individuals, cardiac mucosa is commonly found in a narrow band, less than 3 mm in extent, on the columnar side of the squamo-columnar junction at the end of the esophagus. A greater extent of cardiac mucosa can be found in GERD patients, and the magnitude of that extent appears to be an index of GERD severity. Presently, the risk of adenocarcinoma imposed by cardiac mucosa is not clear, but appears to be far less than that of intestinal metaplasis with goblet cells. The British Society of Gastroenterology accepts an esophagus lined by cardiac mucosa as a “Barrett’s esophagus”. However, if one defines Barrett’s esophagus as a metaplasia that predisposes to cancer, then only intestinal metaplasia clearly fulfills that criterion at this time. Well-designed, prospective studies are needed to establish the malignant potential of cardiac mucosa.