Patient-Specific Biomechanics in Marfan Ascending Thoracic Aortic Aneurysms.

BACKGROUND: Guidelines for sinus of Valsalva (SOV)-thoracic aortic aneurysms in Marfan syndrome recommend size-based criteria for elective surgical repair. Biomechanics may provide a better prediction of dissection risk than diameter. Our aim was to determine magnitudes of wall stress in the aortic root of Marfan patients using finite element analyses. METHODS: Forty-six Marfan patients underwent patient-specific 3-dimensional SOV-thoracic aortic aneurysm geometry reconstruction using imaging data. Finite element analyses were performed to determine wall stress distributions at SOV, sinotubular junction (STJ), and ascending aorta (AscAo) at systole. RESULTS: Peak circumferential stresses were 432.8 ± 111 kPa, 408.1 ± 88.3 kPa, and 321.9 ± 83.8 kPa at the SOV, STJ, and AscAo, respectively, with significant differences between SOV and AscAo (P < 3.08E-07), and STJ and AscAo (P < 2.26E-06). Peak longitudinal wall stresses were 352 ± 73.9 kPa, 277.5 ± 89.5 kPa, and 200.6 ± 81 kPa at SOV, STJ, and AscAo, respectively, with significant differences between SOV and STJ (P < 6.01E-06), SOV and AscAo (P < 9.79E-13), and STJ and AscAo (P < 3.34E-07). Diameter was not correlated to wall stresses. Comparison of wall stresses in aneurysm <5 cm vs ≥5 cm and <4.5 cm vs ≥4.5 cm showed no significant differences in wall stresses in the circumferential or longitudinal direction. CONCLUSIONS: Peak wall stresses in Marfan SOV- thoracic aortic aneurysm were greatest in SOV than STJ than AscAo. Diameter was poorly correlated to peak stresses such that current guidelines with 5 cm cutoff had significant overlap in peak stresses in patients with <5 cm vs ≥5 cm. Use of patient-specific Marfan aneurysm models may identify patients with high wall stresses and small aneurysms who could benefit from earlier surgical repair to prevent aortic dissection.

Nutritional Support in Postcardiotomy Shock Extracorporeal Membrane Oxygenation Patients: A Prospective, Observational Study.

BACKGROUND: Despite the 6000 patients treated with extracorporeal membrane oxygenation (ECMO) annually, there is a paucity of data regarding the nutritional management of these patients. MATERIALS AND METHODS: We performed a prospective, observational study of nutrition in postcardiotomy shock patients at our institution. Over a 3.5-year study period, we identified 50 ECMO patients and 225 non-ECMO patients. We identified type, amount, duration, and disruption of nutritional delivery by cohort. The primary outcome was percent of caloric goal met, and secondary outcome was gastrointestinal complications. RESULTS: ECMO patients met less of their caloric (29% versus 40%, P = 0.017) and protein goals (34% versus 55%, P < 0.001) compared with non-ECMO patients. Tube feeds were administered more slowly (26 versus 37 mL/h, P < 0.001) and held for longer (8.3 versus 4.5 h/d, P < 0.001) in ECMO patients because of procedures (60%) and high-dose pressors (20% versus 7%, P < 0.001). Multivariate analysis demonstrated that ECMO decreased caloric intake by 14%, with no detected increased risk of gastrointestinal complications. CONCLUSIONS: -ECMO patients received significantly less nutrition support compared with a non-ECMO population. Tube feed hold deficits could potentially be avoided by utilizing postpyloric tubes to feed through procedures, by eliminating holds for vasopressors/inotropes in hemodynamically stable patients, or by establishing volume-based feeding protocols. Further clinical studies are needed to establish efficacy of these interventions and to understand the impact of nutrition on outcomes in ECMO patients.

Valve-sparing aortic root replacement in children: Outcomes from 100 consecutive cases.

OBJECTIVE: Valve-sparing root replacement is an attractive alternative to composite mechanical or biologic prostheses for aortic root aneurysms in children. Data on outcomes in pediatric patients are limited. We present our institutional experience with 100 consecutive pediatric valve-sparing aortic root procedures. METHODS: All children who underwent valve-sparing root replacement at our institution from May 1997 to August 2017 were identified, and echocardiographic and clinical data were reviewed. The primary end point was mortality, and secondary end points included complications, further interventions, and subsequent valvular dysfunction. RESULTS: Median age at operation was 13.6 years (interquartile range, 9.42-15.9); 51 patients (51%) had Marfan syndrome, and 39 patients (39%) had Loeys-Dietz syndrome. Mean preoperative maximum sinus diameter was 4.4 ± 0.71 cm (z score 7.3 [5.7-9.3]). Most patients (n = 80, 80%) underwent reimplantation procedures with a Valsalva graft. Four patients (4%) underwent David I reimplantation with a straight-tube graft, 13 patients (13%) underwent a Yacoub remodeling procedure, and 3 patients (3%) underwent a Florida sleeve procedure. Perioperative valve-sparing root replacement mortality was 2% (n = 2). Six patients required late reintervention for development of pseudoaneurysms. Eight patients underwent additional aortic surgery. Average time to reoperation was 7.23 ± 4.56 years. Of the 84 patients undergoing a reimplantation procedure, 5 (5.9%) underwent late valve replacement versus 5 (33.3%) of the 15 patients who received a remodeling procedure (P = .001). CONCLUSIONS: Valve-sparing root replacement is a safe and effective option for children with aortic root aneurysms in children. The reimplantation procedure is preferred. Late aortic insufficiency and pseudoaneurysm formation remain late concerns.

Renal ultrasound provides low utility in evaluating cardiac surgery associated acute kidney injury.

BACKGROUND: Renal ultrasonography is part of the algorithm in assessing acute kidney injury (AKI). The purpose of this study was to assess the clinical utility of renal US in postoperative cardiac patients who develop AKI. METHODS: We conducted a retrospective study of 90 postoperative cardiac surgery patients at a single institution from 1/19/2010 to 3/19/2016 who underwent renal US for AKI. We reviewed provider documentation to determine whether renal US changed management. We defined change as: administration of crystalloid or colloid, addition of inotropic or vasopressor, or procedural interventions on the renal system. RESULTS: Mean age of study patients was 68 ± 13 years. 48/90 patients (53.3%) had pre-existing chronic kidney disease of varying severity. 48 patients (53.3%) had normal renal US with incidental findings and 31 patients (34.4%) had US evidence of medical kidney disease. 10 patients (11.1%) had limited US results due to poor visualization and 1 patient (1.1%) had mild right-sided hydronephrosis. No patients were found to have obstructive uropathy or renal artery stenosis. Clinical management was altered in only 4/90 patients (4.4%), which included 3 patients that received a fluid bolus and 1 patient that received a fluid bolus and inotropes. No vascular or urologic procedures resulted from US findings. CONCLUSION: Although renal ultrasound is often utilized in the work-up of AKI, our study shows that renal US provides little benefit in managing postoperative cardiac patients. This diagnostic modality should be scrutinized rather than viewed as a universal measure in the cardiac surgery population.