Research Spotlight

Webb, J. G., M. J. Mack, J. M. White, D. Dvir, P. Blanke, H. C. Herrmann, J. Leipsic, S. K. Kodali, R. Makkar, D. C. Miller, P. Pibarot, A. Pichard, L. F. Satler, L. Svensson, M. C. Alu, R. M. Suri and M. B. Leon (2017). “Transcatheter aortic valve implantation within degenerated aortic surgical bioprostheses: Partner 2 valve-in-valve registry.” J Am Coll Cardiol 69(18): 2253-2262.

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BACKGROUND: Early experience with transcatheter aortic valve replacement (TAVR) within failed bioprosthetic surgical aortic valves has shown that valve-in-valve (VIV) TAVR is a feasible therapeutic option with acceptable acute procedural results. OBJECTIVES: The authors examined 30-day and 1-year outcomes in a large cohort of high-risk patients undergoing VIV TAVR. METHODS: Patients with symptomatic degeneration of surgical aortic bioprostheses at high risk (>/=50% major morbidity or mortality) for reoperative surgery were prospectively enrolled in the multicenter PARTNER (Placement of Aortic Transcatheter Valves) 2 VIV trial and continued access registries. RESULTS: Valve-in-valve procedures were performed in 365 patients (96 initial registry, 269 continued access patients). Mean age was 78.9 +/- 10.2 years, and mean Society of Thoracic Surgeons score was 9.1 +/- 4.7%. At 30 days, all-cause mortality was 2.7%, stroke was 2.7%, major vascular complication was 4.1%, conversion to surgery was 0.6%, coronary occlusion was 0.8%, and new pacemaker insertion was 1.9%. One-year all-cause mortality was 12.4%. Mortality fell from the initial registry to the subsequent continued access registry, both at 30 days (8.2% vs. 0.7%, respectively; p = 0.0001) and at 1 year (19.7% vs. 9.8%, respectively; p = 0.006). At 1 year, mean gradient was 17.6 mm Hg, and effective orifice area was 1.16 cm2, with greater than mild paravalvular regurgitation of 1.9%. Left ventricular ejection fraction increased (50.6% to 54.2%), and mass index decreased (135.7 to 117.6 g/m2), with reductions in both mitral (34.9% vs. 12.7%) and tricuspid (31.8% vs. 21.2%) moderate or severe regurgitation (all p < 0.0001). Kansas City Cardiomyopathy Questionnaire score increased (mean: 43.1 to 77.0) and 6-min walk test distance results increased (mean: 163.6 to 252.3 m; both p < 0.0001). CONCLUSIONS: In high-risk patients, TAVR for bioprosthetic aortic valve failure is associated with relatively low mortality and complication rates, improved hemodynamics, and excellent functional and quality-of-life outcomes at 1 year.

Shahbazov, R., G. Yoshimatsu, W. Z. Haque, O. S. Khan, G. Saracino, M. C. Lawrence, P. T. Kim, N. Onaca, B. Naziruddin and M. F. Levy (2017). “Clinical effectiveness of a pylorus-preserving procedure on total pancreatectomy with islet autotransplantation.” Am J Surg 213(6): 1065-1071.

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BACKGROUND: The impact of pylorus preserving procedures (PP) on total pancreatectomy with islet autotransplantation (TPIAT) has not been examined. This study aimed to investigate the clinical impact of the PP on TPIAT. METHODS: The Baylor Simmons Transplant Institute database was queried to identify seventy-three patients who underwent TPIAT from 2006 to 2014. All patients were investigated in postoperative complications, long-term nutritional status, and graft function. RESULTS: Patients with PP did not face worse outcomes in terms of delayed gastric emptying and length of hospital stay. Also, nutritional status and metabolic outcome, such as body weight, serum albumin level, serum vitamin level, HbA1c level, graft survival rate and insulin independent rate, were similar between both groups. CONCLUSIONS: Clinical results including the graft function indicated that patients undergoing TPIAT with PP did not amplify surgical complications such as delayed gastric emptying and showed no significant advantage of nutrition and metabolic outcome.

Mogensen, U. M., L. Kober, S. L. Kristensen, P. S. Jhund, J. Gong, M. P. Lefkowitz, A. R. Rizkala, J. L. Rouleau, V. C. Shi, K. Swedberg, M. R. Zile, S. D. Solomon, M. Packer and J. J. V. McMurray (2017). “The effects of sacubitril/valsartan on coronary outcomes in paradigm-hf.” Am Heart J 188: 35-41.

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BACKGROUND: Angiotensin converting enzyme inhibitors (ACE-I), are beneficial both in heart failure with reduced ejection fraction (HF-REF) and after myocardial infarction (MI). We examined the effects of the angiotensin-receptor neprilysin inhibitor sacubitril/valsartan, compared with the ACE-I enalapril, on coronary outcomes in PARADIGM-HF. METHODS AND RESULTS: We examined the effect of sacubitril/valsartan compared with enalapril on the following outcomes: i) the primary composite endpoint of cardiovascular (CV) death or HF hospitalization, ii) a pre-defined broader composite including, in addition, MI, stroke, and resuscitated sudden death, and iii) a post hoc coronary composite of CV-death, non-fatal MI, angina hospitalization or coronary revascularization. At baseline, of 8399 patients, 3634 (43.3%) had a prior MI and 4796 (57.1%) had a history of any coronary artery disease. Among all patients, compared with enalapril, sacubitril/valsartan reduced the risk of the primary outcome (HR 0.80 [0.73-0.87], P<.001), the broader composite (HR 0.83 [0.76-0.90], P<.001) and the coronary composite (HR 0.83 [0.75-0.92], P<.001). Although each of the components of the coronary composite occurred less frequently in the sacubitril/valsartan group, compared with the enalapril group, only CV death was reduced significantly. CONCLUSIONS: Compared with enalapril, sacubitril/valsartan reduced the risk of both the primary endpoint and a coronary composite outcome in PARADIGM-HF. Additional studies on the effect of sacubitril/valsartan on atherothrombotic outcomes in high-risk patients are merited.

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.

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].

Full text of this article.

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.