Total Aortic Arch Replacement: Superior Ventriculo-Arterial Coupling with Decellularized Allografts Compared with Conventional Prostheses.

BACKGROUND: To date, no experimental or clinical study provides detailed analysis of vascular impedance changes after total aortic arch replacement. This study investigated ventriculoarterial coupling and vascular impedance after replacement of the aortic arch with conventional prostheses vs. decellularized allografts. METHODS: After preparing decellularized aortic arch allografts, their mechanical, histological and biochemical properties were evaluated and compared to native aortic arches and conventional prostheses in vitro. In open-chest dogs, total aortic arch replacement was performed with conventional prostheses and compared to decellularized allografts (n = 5/group). Aortic flow and pressure were recorded continuously, left ventricular pressure-volume relations were measured by using a pressure-conductance catheter. From the hemodynamic variables end-systolic elastance (Ees), arterial elastance (Ea) and ventriculoarterial coupling were calculated. Characteristic impedance (Z) was assessed by Fourier analysis. RESULTS: While Ees did not differ between the groups and over time (4.1+/-1.19 vs. 4.58+/-1.39 mmHg/mL and 3.21+/-0.97 vs. 3.96+/-1.16 mmHg/mL), Ea showed a higher increase in the prosthesis group (4.01+/-0.67 vs. 6.18+/-0.20 mmHg/mL, P<0.05) in comparison to decellularized allografts (5.03+/-0.35 vs. 5.99+/-1.09 mmHg/mL). This led to impaired ventriculoarterial coupling in the prosthesis group, while it remained unchanged in the allograft group (62.5+/-50.9 vs. 3.9+/-23.4%). Z showed a strong increasing tendency in the prosthesis group and it was markedly higher after replacement when compared to decellularized allografts (44.6+/-8.3dyn.sec.cm-5 vs. 32.4+/-2.0dyn.sec.cm-5, P<0.05). CONCLUSIONS: Total aortic arch replacement leads to contractility-afterload mismatch by means of increased impedance and invert ventriculoarterial coupling ratio after implantation of conventional prostheses. Implantation of decellularized allografts preserves vascular impedance thereby improving ventriculoarterial mechanoenergetics after aortic arch replacement

Is simultaneous splenectomy an additive risk factor in surgical treatment for active endocarditis?

Purpose: Splenic abscess formation is a serious complication in the setting of active endocarditis, and splenectomy is recommended. However, the optimal timing for splenectomy is yet undetermined. The purpose of this study was to evaluate the role of a one-stage splenectomy and valve surgery for active endocarditis. Methods: Among 202 consecutive endocarditis patients, 18 had splenic lesions on preoperative abdominal screening, who underwent cardiac surgery and splenectomy as a one-stage procedure (group A) and were compared to patients with unremarkable abdominal screening (group B, n = 184) undergoing sole cardiac surgery. Results: No difference was observed regarding preoperative characteristics (age, gender, New York Heart Association [NYHA] grade, diabetes, coronary artery disease, redo surgery, adiposity, smoking), intubation time, and prolonged ventilation. There were 23 early postoperative deaths in group B (12.5%) vs. none in group A. At 180 days, survival was significantly higher for patients in group A (94.4%) vs. group B (67.9%, p = 0.016), although this difference did not reach statistical significance (log-rank test, p = 0.073). Multivariate Cox proportional hazards regression revealed age above 50 years (hazard ratio [HR] 3.327, 95% confidence interval [CI] 1.279-8.650) and NYHA class above III (NYHA III or IV: HR 3.117, 95% CI 1.119-8.683, p = 0.030; NYHA IV: HR 3.678, 95% CI 1.984-6.817, p < 0.001) as independent risk factors for mortality at 180 days. A trend towards a protective factor was observed for simultaneous splenectomy (HR = 0.171, 95% CI 0.023-1.255). Conclusion: Simultaneous valve surgery and splenectomy is an approach for active endocarditis complicated by splenic lesions with a low 180-day mortality. Despite the expected risk elevation by septic lesions and the additive trauma of a laparotomy, patients with simultaneous splenectomy had a favourable outcome regarding early mortality and mortality at 6 months