Optimal pH-management during operations requiring hypothermic circulatory arrest:an experimental study employing pH- and/or α-stat strategies during cardiopulmonary bypass

Abstract Cessation of the blood circulation for some time during surgery of the aortic arch and repair of congenital heart defects is normally required to allow a bloodless operation field. Hypothermia is the most important mechanism for end-organ protection, particularly the brain, during such operations. Cardiopulmonary bypass is used for core cooling before total hypothermic circulatory arrest (HCA) or selective cerebral perfusion (SCP) are initiated. During hypothermic cardiopulmonary bypass, pH can be managed according to either pH- or alpha-stat principles. In the present work, the optimal pH management strategy for operations requiring HCA or SCP was explored. An experimental porcine model was used. Firstly, outcome was evaluated in a HCA model using either the α- or pH-stat perfusion strategy (I). Secondly, we sought to determine which acid-base management is more effective in attenuating ischemic brain injury during combined HCA and embolization conditions (II). In the third study, the impact of propofol anesthesia and α-stat perfusion strategy on outcome was explored (III). Finally, the acute effects of perfusion strategies in a SCP porcine were compared (IV). Hemodynamics, temperature, EEG (I-III), brain microdialysis, intracranial pressure (I-III), brain tissue oxygen partial pressure (I-III), and intravital microscopy (IV) were monitored intraoperatively. In the chronic studies, survival, postoperative neurologic recovery and brain histopathologic examination were evaluated (I-III). pH-stat strategy was associated with superior outcome compared to the α-stat strategy during a 75-minute period of deep HCA (I). In addition, despite the pH-stat strategy-related cerebral vasodilatation, this method provided better neuroprotection in a setting of cerebral particle embolization prior to a 25-minute period of deep HCA (II). Propofol anesthesia combined with α-stat perfusion strategy was observed to deteriorate the brain injury during HCA evaluated by key brain microdialysis parameters (III). Finally, when employing moderately hypothermic SCP, the differences between pH- and α-stat strategies in cerebral metabolism and microcirculation were minimal. These findings are clinically relevant since α-stat perfusion strategy is still the most commonly used acid-base perfusion strategy during hypothermic cardiopulmonary bypass in adults, and propofol one of the most used anesthetics in clinical practice. It is also noteworthy that the pH-stat strategy is not currently used in adults because of the perceived increased risk of atherosclerotic embolization. However, the advantage of pH-stat strategy over α-stat strategy could not be observed when employing SCP

Comparison of survival of transfemoral transcatheter aortic valve implantation versus surgical aortic valve replacement for aortic stenosis in low-risk patients without coronary artery disease

Abstract Increasing data support transcatheter aortic valve implantation (TAVI) as a valid option over surgical aortic valve replacement (SAVR) in the treatment for severe aortic stenosis (AS) also in patients with low operative risk. However, limited data exist on the outcome of TAVI and SAVR in low-risk patients without coronary artery disease (CAD). The FinnValve registry included data on 6463 patients who underwent TAVI or SAVR with bioprosthesis between 2008 and 2017. Herein, we evaluated the outcome of low operative risk as defined by STS-PROM score <3% and absence of CAD, previous stroke and other relevant co-morbidities. Only patients who underwent TAVI with third-generation prostheses and SAVR with Perimount Magna Ease or Trifecta prostheses were included in this analysis. The primary endpoints were 30-day and 3-year all-cause mortality. Overall, 1,006 patients (175 TAVI patients and 831 SAVR patients) met the inclusion criteria of this analysis. Propensity score matching resulted in 140 pairs with similar baseline characteristics. Among these matched pairs, 30-day mortality was 2.1% in both TAVI and SAVR cohorts (p = 1.00) and 3-year mortality was 17.0% after TAVI and 14.6% after SAVR (p = 0.805). Lower rates of bleeding and atrial fibrillation, and shorter hospital stay were observed after TAVI. The need of new permanent pacemaker implantation and the incidence of early stroke did not differ between groups. In conclusion, TAVI using third-generation prostheses achieved similar early and mid-term survival compared with SAVR in low-risk patients without CAD

Perioperative bleeding requiring blood transfusions is associated with increased risk of stroke after transcatheter and surgical aortic valve replacement

Abstract Objectives: The authors aimed to investigate the impact of severe bleeding and use of red blood cell (RBC) transfusion on the development of postoperative stroke after surgical (SAVR) and transcatheter aortic valve replacement (TAVR), taken from the FinnValve registry. Design: Nationwide, retrospective observational study. Setting: Five Finnish university hospitals participated in the registry. Participants: A total of 6,463 patients who underwent SAVR (n = 4,333) or TAVR (n = 2,130). Interventions: Patients who underwent TAVR or SAVR with a bioprosthesis with or without coronary revascularization. Measurements and Main Results: The incidence of postoperative stroke after SAVR was 3.8%. In multivariate analysis, the number of transfused RBC units (odds ratio [OR], 1.098; 95% confidence interval [CI], 1.064–1.133) was one of the independent predictors of postoperative stroke. The incidence of stroke increased, along with the severity of perioperative bleeding, according to the European Coronary Artery Bypass Grafting (E-CABG) bleeding grades were as follows: grade 0, 2.2% (reference group); grade 1, 3.4% (adjusted OR, 1.841; 95% CI, 1.105–3.066); grade 2, 5.5% (adjusted OR, 3.282; 95% CI, 1.948–5.529); and grade 3, 14.8% (adjusted OR, 7.103; 95% CI, 3.612–13.966). The incidence of postoperative stroke after TAVR was 2.5%. The number of transfused RBC units was an independent predictor of stroke after TAVR (adjusted OR, 1.155; 95% CI, 1.058–1.261). The incidence of postoperative stroke increased, along with the severity of perioperative bleeding, as stratified by the E-CABG bleeding grades: E-CABG grade 0, 1.7%; grade 1, 5.3% (adjusted OR, 1.270; 95% CI, 0.532–3.035); grade 2, 10.0% (adjusted OR, 2.898; 95% CI, 1.101–7.627); and grade 3, 30.0% (adjusted OR, 10.706; 95% CI, 2.389–47.987). Conclusions: Perioperative bleeding requiring RBC transfusion and/or reoperation for intrathoracic bleeding is associated with an increased risk of postoperative stroke after SAVR and TAVR. Patient blood management and meticulous preprocedural planning and operative technique aiming to avoid significant perioperative bleeding may reduce the risk of cerebrovascular complications

Mid-term outcomes of Sapien 3 versus Perimount Magna Ease for treatment of severe aortic stenosis

Abstract Background: There is limited information on the longer-term outcome after transcatheter aortic valve replacement (TAVR) with new-generation prostheses compared to surgical aortic valve replacement (SAVR). The aim of this study was to compare the mid-term outcomes after TAVR with Sapien 3 and SAVR with Perimount Magna Ease bioprostheses for severe aortic stenosis. Methods: In a retrospective study, we included patients who underwent transfemoral TAVR with Sapien 3 or SAVR with Perimount Magna Ease bioprosthesis between January 2008 and October 2017 from the nationwide FinnValve registry. Propensity score matching was performed to adjust for differences in the baseline characteristics. The Kaplan-Meir method was used to estimate late mortality. Results: A total of 2000 patients were included (689 in the TAVR cohort and 1311 in the SAVR cohort). Propensity score matching resulted in 308 pairs (STS score, TAVR 3.5 ± 2.2% vs. SAVR 3.5 ± 2.8%, p = 0.918). In-hospital mortality was 3.6% after SAVR and 1.3% after TAVR (p = 0.092). Stroke, acute kidney injury, bleeding and atrial fibrillation were significantly more frequent after SAVR, but higher rate of vascular complications was observed after TAVR. The cumulative incidence of permanent pacemaker implantation at 4 years was 13.9% in the TAVR group and 6.9% in the SAVR group (p = 0.0004). At 4-years, all-cause mortality was 20.6% for SAVR and 25.9% for TAVR (p = 0.910). Four-year rates of coronary revascularization, prosthetic valve endocarditis and repeat aortic valve intervention were similar between matched cohorts. Conclusions: The Sapien 3 bioprosthesis achieves comparable midterm outcomes to a surgical bioprosthesis with proven durability such as the Perimount Magna Ease. However, the Sapien 3 bioprosthesis was associated with better early outcome

Comparison of outcomes after transcatheter aortic valve replacement vs surgical aortic valve replacement among patients with aortic stenosis at low operative risk

Abstract Importance: Transcatheter aortic valve replacement (TAVR) has been shown to be a valid alternative to surgical aortic valve replacement (SAVR) in patients at high operative risk with severe aortic stenosis (AS). However, the evidence of the benefits and harms of TAVR in patients at low operative risk is still scarce. Objective: To compare the short-term and midterm outcomes after TAVR and SAVR in low-risk patients with AS. Design, Setting, and Participants: This retrospective comparative effectiveness cohort study used data from the Nationwide Finnish Registry of Transcatheter and Surgical Aortic Valve Replacement for Aortic Valve Stenosis of patients at low operative risk who underwent TAVR or SAVR with a bioprosthesis for severe AS from January 1, 2008, to November 30, 2017. Low operative risk was defined as a Society of Thoracic Surgeons Predicted Risk of Mortality score less than 3% without other comorbidities of clinical relevance. One-to-one propensity score matching was performed to adjust for baseline covariates between the TAVR and SAVR cohorts. Exposures: Primary TAVR or SAVR with a bioprosthesis for AS with or without associated coronary revascularization. Main Outcomes and Measures: The primary outcomes were 30-day and 3-year survival. Results: Overall, 2841 patients (mean [SD] age, 74.0 [6.2] years; 1560 [54.9%] men) fulfilled the inclusion criteria and were included in the analysis; TAVR was performed in 325 patients and SAVR in 2516 patients. Propensity score matching produced 304 pairs with similar baseline characteristics. Third-generation devices were used in 263 patients (86.5%) who underwent TAVR. Among these matched pairs, 30-day mortality was 1.3% after TAVR and 3.6% after SAVR (P = .12). Three-year survival was similar in the study cohorts (TAVR, 85.7%; SAVR, 87.7%; P = .45). Interaction tests found no differences in terms of 3-year survival between the study cohorts in patients younger than vs older than 80 years or in patients who received recent aortic valve prostheses vs those who did not. Conclusions and Relevance: Transcatheter aortic valve replacement using mostly third-generation devices achieved similar short- and mid-term survival compared with SAVR in low-risk patients. Further studies are needed to assess the long-term durability of TAVR prostheses before extending their use to low-risk patients