Brain Oxygen Supply in Older Adults During Coronary Artery Bypass Grafting

ObjectivesTo evaluate the dynamics of the cerebral oxygen supply in patients aged ≥65 years, during coronary artery bypass grafting (CABG), and to test the hypothesis that lower intraoperative brain oxygen saturation is associated with postoperative neurological complications.DesignProspective cohort study.SettingThe E. Meshalkin National Medical Research Center of the Ministry of Health of the Russian Federation, Novosibirsk, Russia.ParticipantsThe study comprised 200 elderly patients who underwent CABG between April, 2018 and November, 2019.InterventionsNone.Measurements and Main ResultsThe regional hemoglobin oxygen saturation (rSO₂, %) of the right and left brain hemispheres were assessed during the intraoperative period using bilateral near-infrared spectroscopy. Furthermore, neurological complications during hospitalization were evaluated. At the anesthesia induction stage, the average levels of rSO₂ for the right and left hemispheres were within 65% and did not differ significantly at any stage of CABG (p>0.05). The risk of neurological complications was associated with rSO₂ decrease during cardiopulmonary bypass (CPB). An increased risk was associated with rSO₂ decrease by 20% or more during CPB, relative to the stage of anesthesia induction, which was observed in 19% of patients.ConclusionsIn elderly patients, the decrease in rSO₂ during CPB is associated with an increased risk of neurological complications during hospitalization. This risk increases with a decrease in rSO₂ by 20% or more during CPB relative to the stage of anesthesia induction, by a 5-fold and 7-fold for the left and right hemispheres, respectively.     

Intra-aortic balloon pump induced pulsatile perfusion reduces endothelial activation and inflammatory response following cardiopulmonary bypass

Objective: Intra-aortic balloon pump (IABP)-induced pulsatile perfusion has demonstrated that it can preserve organ function during cardiopulmonary bypass (CPB). We evaluated the role of IABP pulsatile perfusion on endothelial response. Methods: Forty consecutive isolated CABG undergoing preoperative IABP were randomized to receive IABP pulsatile CPB during aortic cross-clamping (group A, 20 patients) or standard linear CPB (group B, 20 patients) during cross-clamp time. Hemodynamic results were analyzed by Swan-Ganz catheter [mean arterial pressure (MAP), cardiac index (CI), indexed systemic vascular resistances (ISVR), indexed pulmonary vascular resistances (IPVR), wedge pressure (PCWP)]. Inflammatory/endothelial response was analyzed by pro-inflammatory (IL-2, IL-6, IL-8), anti-inflammatory cytokines (IL-10), and endothelial markers [vascular endothelial growth factor (VEGF) and monocyte chemotactic protein-1 (MCP-1)]. All measurements were recorded preoperatively (T0), before aortic declamping (T1), at the end of surgery (T2), 12 h (T3) and 24 h (T4) postoperatively. ANOVA for repeated measures was used to evaluate the differences of means. Results: Hemodynamic response was comparable except for higher MAP (p = 0.01 at T1) and lower ISVR (p = 0.001 at T1, p = 0.003 at T2) in group A. No differences were found in perioperative leakage of IL-2, IL-6, and IL-8 between the two groups (within-group p = 0.0001 either in group A and group B; between-groups p = NS at 2-ANOVA). Group A showed significantly lower VEGF (between-groups p = 0.001 at 2-ANOVA, p = 0.001 at T1, T2) and MCP-1 (between-groups p = 0.001 at 2-ANOVA, p = 0.001 at T1, T2) with higher IL-10 secretion (between-groups p = 0.001 at 2-ANOVA, p = 0.01 at T1, T2, T3). Conclusions: IABP-induced pulsatile perfusion allows lower endothelial activation during CPB and higher anti-inflammatory cytokines secretion.     

Vascular Growth Factor and Gene Therapy to Induce New Vessels in the Ischemic Myocardium. Therapeutic Angiogenesis

Objective. To investigate oxidative stress and myocardial injury at different stages of coronary artery bypass grafting (CABG). Design. Twenty patients underwent CABG with use of cardiopulmonary bypass (CPB) and with intermittent sampling of plasma and urine. Main markers were: 8-iso-PGF_2α (oxidative stress); troponin T (myocardial injury); and 15-keto-dihydro-PGF_2α and hsCRP (inflammation). Results. Plasma 8-iso-PGF_2α increased after start of surgery, but there was no further rise during CPB or after aortic cross-clamp release and no significant myocardial arterio-venous differences. An increase in troponin T was seen early after the operation, but no relationship was established between 8-iso-PGF_2α and troponin T. 8-iso-PGF_2α levels were elevated by preoperative withdrawal of acetylsalicylic acid (ASA) but reduced by intraoperative use of heparin. 15-keto-dihydro-PGF_2α was elevated during operation and hsCRP following operation. Conclusions. In the present study oxidative stress was multifactorial in origin with main impacts from surgical trauma, less from CPB and little if any from myocardial ischemia-reperfusion events. In addition, cardiovascular drugs in common use like ASA and heparin seemed to influence the pro- and antioxidant balance, a finding that has to be confirmed in future studies.     

Comparison of del Nido Cardioplegia vs. blood cardioplegia in adult aortic surgery: Is the single-dose cardioplegia technique really advantageous?

Background/objective: The aim of the present study was to compare the operative and early postoperative results of the use of del Nido Cardioplegia solution (dNCS) with traditional blood cardioplegia (BC) in adult aortic surgery.MethodsA retrospective single-center study was performed on 118 patients who underwent aortic surgery with cardiopulmonary bypass (CPB) between January 2016 and June 2020. Patients were divided in to two groups according to the type of cardioplegia solution used. Cardiac arrest was achieved in Group 1 (n = 65) with traditional BC and in Group 2 (n = 53) with dNCS. Operative and postoperative outcomes of the patients were compared between the two groups.ResultsPatient demographic characteristics were similar between the two groups. dNCS group showed significantly lower aortic cross-clamp (ACC) time (73.3 vs. 87.5 min, P = 0.001), cardioplegia volume (1323.9 ± 368.5 vs. 2773.8 ± 453.8 ml, P< 0.001), defibrillation rate (44.4%vs. 69.2%, P = 0.006), drainage amount (412 ± 73.2 vs. 446.9 ± 95.1 ml, P = 0.026) and inotropic support need (37% vs. 55.3%, P = 0.046). Also dNCS group had significantly lower high sensitive troponin I (hsTnI) levels at 6th (203.5 ± 68.6 vs. 275.7 ± 76.2 ng/L, P< 0.001) and 24th (253.1 ± 101 vs. 293.4 ± 80.1 ng/L, P = 0.017) postoperative hours. And dNCS group showed significantly higher hematocrit levels at 6th (25.1 ± 3.2 vs. 22.5 ± 2.5%, P< 0.001) and 24th (25.8 ± 2.7 vs. 24.6 ± 2.8%, P = 0.024) postoperative hours. Times of intensive care unit stay, durations of intuabation and hospital stay times were similar in both groups. There was no significant difference in terms of postoperative ejection fraction values (P = 0.714).ConclusionCompared with conventional BC, dNCS provided significantly shorter ACC times, reduced the need for intraoperative defibrillation, lowered postoperative hsTnI levels with comparable early clinical outcomes for adult patients undergoing aortic surgery. dNCS is a safe and efficient alternative to the traditional BC solution in adult aortic cardiac surgery.     

Associations between mean arterial pressure during cardiopulmonary bypass and biomarkers of cerebral injury in patients undergoing cardiac surgery: secondary results from a randomized controlled trial

Open in a separate window OBJECTIVESCardiac surgery is associated with risk of cerebral injury and mean arterial pressure (MAP) during cardiopulmonary bypass (CPB) is suggested to be associated with cerebral injury. The ‘Perfusion Pressure Cerebral Infarcts’ (PPCI) trial randomized patients undergoing coronary artery bypass grafting (CABG) and/or aortic valve replacement to a MAP of 40–50 or 70–80 mmHg during CPB and found no difference in clinical or imaging outcomes between the groups. We here present PPCI trial predefined secondary end points, consisting of biomarkers of brain injury.METHODSBlood was collected from PPCI trial patients at baseline, 24 and 48 h after induction of anaesthesia and at discharge from the surgical ward. Blood was analysed for neuron-specific enolase, tau, neurofilament light and the glial marker glial fibrillary acidic protein. Linear mixed models were used to analyse differences in biomarker value changes from baseline between the 2 MAP allocation groups.RESULTSA total of 193 (98%) patients were included. We found no differences in biomarker levels over time from baseline to discharge between the 2 MAP allocation groups (P_NSE = 0.14, P_Tau = 0.46, P_NFL = 0.21, P_GFAP = 0.13) and the result did not change after adjustment for age, sex and type of surgery.CONCLUSIONSWe found no significant differences in levels of biomarkers of neurological injury in patients undergoing elective or subacute CABG and/or aortic valve replacement randomized to either a target MAP of 40–50 mmHg or a target MAP of 70–80 mmHg during CBP.     

Clinical effectiveness of leukocyte filtration during cardiopulmonary bypass in patients with chronic obstructive pulmonary disease

Background

We tested the hypothesis that leukocyte filtration during pulmonary reperfusion preserves pulmonary function and results in improved oxygenation after cardiopulmonary bypass (CPB) in patients with chronic obstructive pulmonary disease (COPD).

Methods

In a prospective, randomized study, the treatment group consisted of 20 patients with COPD from consecutive open-heart procedures. A primed leukocyte filter was connected to the arterial line downstream of the standard arterial filter but was excluded from circulation. Circulated blood was directed through the leukocyte filter approximately 10 minutes before aortic cross-clamp removal and at early reperfusion for up to 30 minutes. These patients were compared to 20 additional COPD patients (controls) on whom systemic leukocyte filtration was not used during open-heart surgery.

Results

There was no significant difference in gender, age, left ventricular ejection fraction, type of procedure, aortic cross-clamp time, perfusion time, preoperative FEV₁ and preoperative respiratory index (Pao₂/FiO₂ ratio) between treatment and control groups. The respiratory index changed in the treatment group by +9.8% of baseline after completion of CPB, by −14.2% upon arrival in the intensive care unit (ICU), and by −19.6% 12 hours later, whereas in the control group, it changed by −14.5% (p < 0.05), −27.7%, and −24%, respectively. Leukocyte-depleted patients required shorter intubation time (20.4 ± 16.1 hours), ICU stay (46.2 ± 40.1 hours) and length of hospitalization (8.3 ± 2.8 days) than controls (29.5 ± 21.9 hours, p < 0.05; 75.5 ± 34.9 hours, p < 0.005; and 10.4 ± 3.5 days, p < 0.05, respectively). Surgical (30-day) mortality was zero in both groups.

Conclusions

In COPD patients having CPB, systemic leukocyte depletion at early reperfusion was associated with better oxygenation, shorter intubation time, and shorter ICU and hospital stays. Leukocyte filtration during CPB most likely preserves pulmonary function by ameliorating pulmonary reperfusion injury.     

Concomitant coronary artery bypass grafting during surgical repair of acute type A aortic dissection affects operative mortality rather than midterm mortality

BackgroundIn this study, we investigated the impact of concomitant coronary artery bypass grafting (CABG) on operative and midterm mortality in patients with acute type A aortic dissection (ATAAD) undergoing surgical repair.MethodsFrom January 2012 to December 2014, among 489 patients (mean age: 47.6 ± 10.4 years, 77.1% male) with ATAAD who received surgical repair at our institute, 21 patients (4.3%) underwent concomitant CABG. Isolated aortic repair was performed in the remaining 468 cases (95.7%). Coronary dissection was indicated in 15 patients (Neri classification type B in 2, type C in 13), concomitant coronary artery disease in five and coronary artery compression in one. The follow-up time was 97.3% at 44.1 ± 13.9 months.ResultsA total of 44 patients (9%) died from surgery, and operative mortality in the concomitant CABG group was significantly higher than that in the isolated aortic repair group (47.6%, 10/21 vs. 7.3%, 34/468; P < 0.001). Among the 11 survivors in the concomitant CABG group, no deaths occurred during the follow-up. Cox regression indicated that concomitant CABG increased the operative mortality risk by 9.2 times (HR, 9.26; 95% CI, 4.31–19.89; P < 0.001). Although it predicted a 5.2-fold increase in overall mortality (HR, 5.20; 95% CI, 2.55–10.61; P < 0.001), concomitant CABG did not affect midterm death (P = 0.996).ConclusionsConcomitant CABG carries a significant operative risk in ATAAD patients undergoing surgical repair. However, survivors may benefit from concomitant CABG and had similar midterm mortality compared with the other cases.     

Renal cell carcinoma with IVC and atrial thrombus: A single centre's 10 year surgical experience

Renal cell carcinoma (RCC) propagates into the IVC in 4% of cases with 1% extending into the right atrium. Radical surgical resection remains the definitive curative/palliative treatment in those without significant metastases. The aim was to review our experience in patients with different levels of IVC involvement, cardiopulmonary bypass (CPB) and perioperative/long term outcomes.Patients and methodsFrom 2001 to 2012, 24 radical nephrectomies with IVC thrombectomy were performed. A retrospective chart review was undertaken to record demographics, presenting symptoms, duration of surgery, peri-operative transfusion, CPB and peri-operative complications, tumour grade/stage, and patient survival.ResultsWe identified 24 patients (18 male, Age median 59 range 35–78). The commonest presenting symptoms were weight loss, pain and haematuria. The majority of tumours were right sided (n = 17) with 8 having lung metastases at presentation. Thrombus level was 16 (infradiaphragmatic), 2 (supradiaphragmatic), 6 (intra-atrial). 15 patients required sternotomy for vascular control and 9 required CPB both with a significantly longer operative time compared (6.1 ± 3.5 vs. 7.2 ± 1.2 vs. 3.5 ± 1.1 h, respectively). Peri-operative complications (n = 21) included cardiopulmonary, renal, gastrointestinal and septic problems. There were 2 peri-operative deaths. Blood transfusion was significantly less in those not requiring sternotomy or CPB using the "Cell Saver" device. The majority were Fuhrman grade 3 (n = 16) and clear cell type (n = 14). Overall 3-year survival was 100% (Laparotomy only), 40% (sternotomy + cross-clamp), and 20% (CPB).ConclusionsIVC thrombectomy has significant morbidity and requires careful patient selection and a multi-disciplinary approach to optimise patient outcomes. In this series, the level of IVC thrombus and requirement for CPB directly affects patient morbidity and outcome.     

The impact of invasive respiratory support on the development of postoperative atrial fibrillation following cardiac surgery

Study objectivePostoperative atrial fibrillation (POAF) is a frequent complication after cardiac valve- or coronary artery bypass (CABG) surgery and is associated with increased mortality. While it is known that prolonged postoperative invasive ventilation triggers POAF, the impact of ventilatory settings on POAF development has not been studied yet.DesignProspective observational study.SettingPostoperative Intensive Care Unit.PatientsPatients having undergone elective CABG and/or cardiac valve surgery.MeasurementsScreening for the development of POAF. Patients' clinical data and postoperative ventilatory settings (driving pressure, controlled pressure above positive endexpiratory pressure (PEEP), respiration rate, and FiO2) were investigated to elucidate their impact on POAF.Main resultsOut of 441 enrolled individuals, a total of 192 participants developed POAF (43.5%). We observed that POAF patients received a higher peak driving pressure, and a higher peak respiration rate than non-POAF individuals. Within the multivariate regression model, plateau pressure (adjusted OR 1.199 [1.038–1.661], p = 0.019), driving pressure (adjusted OR 1.244 [1.103–1.713], p = 0.021), and peak respiration rate (adjusted OR 1.206 [1.005–1.601], p = 0.040) proved to be independently associated with the development of POAF. CART analysis revealed a cut-off of ≥17.5 cmH₂O of plateau pressure, ≥11.5 cmH₂O of driving pressure and ≥ 17 respirations per minute as high-risk for POAF development.ConclusionsThe ventilatory settings of plateau pressure, driving pressure, and respiration rate after cardiac surgery influence POAF occurrence probability. Optimized postoperative care such as lung-protective ventilation and increased awareness towards postoperative ventilatory efforts should be considered to prevent POAF development and poor patient outcome.     

The association of bispectral index values and metrics of cerebral perfusion during cardiopulmonary bypass

Study objectiveLow bispectral index (BIS) values have been associated with adverse postoperative outcomes. However, trials of optimizing BIS by titrating anesthetic administration have reported conflicting results. One potential explanation is that cerebral perfusion may also affect BIS, but the extent of this relationship is not clear. Therefore, we examined whether BIS would be associated with cerebral perfusion during cardiopulmonary bypass, when anesthetic concentration was constant.DesignObservational cohort study.SettingCardiac operating room.PatientsSeventy-nine patients with cardiopulmonary bypass surgery were included.MeasurementsContinuous BIS, mean arterial blood pressure (MAP), cerebral blood flow velocity (CBFV), and regional cerebral oxygen saturation (rSO₂) were monitored, with analysis during a period of constant anesthetic. Mean flow index (Mx) was calculated as Pearson correlation between MAP and CBFV. The lower limit of autoregulation (LLA) was identified as the MAP value at which Mx increased >0.4 with decreasing blood pressure. Postoperative delirium was assessed using the 3D-Confusion Assessment Method.ResultsMean BIS was lower during periods of MAP < LLA compared with BIS when MAP>LLA (mean 49.35 ± 10.40 vs. 50.72 ± 10.04, p = 0.002, mean difference = 1.38 [standard error: 0.42]). There was a dose response effect, with the BIS proportionately decreasing as MAP decreased below LLA (β = 0.15, 95% CI for the average slope across all patients 0.07 to 0.23, p < 0.001). In contrast, BIS was relatively unchanged when MAP was above LLA (β = 0.03, 95% CI for the average slope across all patients −0.02 to 0.09, p = 0.22). Additionally, increasing CBFV and rSO₂ were associated with increasing BIS. Patients with postoperative delirium had lower mean BIS and higher percentage of time duration with BIS <45 compared to patients without delirium.ConclusionsThere was an association of BIS and metrics of cerebral perfusion during a period of constant anesthetic administration, but the absolute magnitude of change in BIS as MAP decreased below the LLA was small.     

Histamine release during paediatric cardiopulmonary bypass

Histamine release is part of the general inflammatory response and occurs during surgery and cardiopulmonary bypass (CPB) in adults. Few data are available for children. Histamine release was studied in 23 children undergoing CPB with standard anaesthetic and CPB techniques. Blood sampling was performed in relation to specific anaesthetic and surgical events, e.g., start of CPB, removal of aortic clamps, reventilation of the lungs. Plasma histamine was determined by a single isotope radioenzymatic technique. There was no consistent histamine release in the study population although there was an increase in plasma histamine concentration in some subjects after initiation of CPB (P <0.05) and on removal of the aortic cross-clamp (P <0.05). No correlation was demonstrated between histamine concentration and systolic arterial pressure, temperature, duration of CPB or cross-clamp time. Histamine concentration was positively correlated with heart rate.     

Pulsatile pulmonary perfusion with oxygenated blood ameliorates pulmonary hemodynamic and respiratory indices in low-risk coronary artery bypass patients

Objective: Acute lung injury still accounts for postoperative mortality after cardiopulmonary bypass (CPB). The safety and the efficacy of pulsatile pulmonary perfusion (PPP) during CPB were analyzed. Preliminary results of the first PPP trial in human beings are reported. Methods: Thirty low-risk coronary artery bypass grafting (CABG) patients were prospectively randomized to receive PPP with oxygenated blood during CPB and aortic cross-clamping (15 patients, PPP-group) or to conventional CPB (15 patients, control group). Alveolo–arterial oxygen gradient (A-aDO₂) was set as the primary end point and collected preoperatively, at intensive care unit (ICU) arrival (T1), 3 h postoperatively (T2), and post extubation (T3). Secondary end points were collected at the same time points and consisted of respiratory indices (partial pressure of arterial oxygen/fraction of inspired O₂ (PaO₂/FiO₂), lung compliance, mixed-venous partial pressure of oxygen (pO₂)) and hemodynamic pulmonary parameters (indexed pulmonary vascular resistances (PVRI), pulmonary arterial pressure (PAP), pulmonary capillary wedge pressure (PCWP), and cardiac index (CI)). Bronchoalveolar lavage (BAL) fluid was collected preoperatively, at ICU arrival (T1-BAL) and after 4 h. Results: There were no PPP-related complications. Patients undergoing PPP showed a better preserved A-aDO₂ (group-p = 0.001) throughout the study period (group × time-p = 0.0001). PaO₂/FiO₂ and lung compliance were better preserved by PPP (group-p and group × time-p ≤ 0.05 for all). Pulmonary hemodynamic status was positively influenced by PPP, as shown by the higher CI (group-p = 0.0001, group × time-p = 0.0001), and the lower PVRI, PAP, and PCWP (group-p ≤ 0.001, group × time-p = 0.0001 for all). Postoperative BAL specimens demonstrated a lower absolute count of white blood cells (group-p = 0.0001), a higher percentage of monocytes/macrophages (group-p = 0.027), and a lower percentage of neutrophils (group-p = 0.015) after PPP. Conclusions: Oxygenated blood PPP proved safe and significantly ameliorated pulmonary hemodynamic parameters and respiratory indices in low-risk CABG.     

Anatomical circumstances and aortic cross-clamp time in minimally invasive aortic valve replacement

Open in a separate window OBJECTIVESProlonged operative times, potentially leading to increased morbidity, are a possible drawback of minimally invasive aortic valve replacement. The aim of this study was to assess the impact of anatomical circumstances in the chest on aortic cross-clamp time. METHODSThis retrospective study included 68 patients who underwent minimally invasive aortic valve replacement with the Perceval sutureless valve via right-anterior thoracotomy or with ministernotomy. Anatomical variables were measured during preoperative computer tomography scans.RESULTSAortic cross-clamp time was shorter in those having ministernotomy than in the right-anterior thoracotomy group (41.1 vs 52.3 min; P < 0.001). Cardiopulmonary bypass (CPB) time was not significantly different between groups (P = 0.09). A multivariable linear-regression model (P = 0.018) showed the aortic dextroposition variable to be a significant predictor of the aortic cross-clamp method and CPB times (P = 0.005 and P = 0.003) independent of other anatomical variables in the right thoracotomy group (10 mm deviation from optimal position prolonged the times for 240 and 600 s). For the whole cohort, a correlation between aortic valve dimensions and operative times was found (P = 0.046, P = 0.009). A linear-regression model (P = 0.046) predicted 90 s longer aortic cross-clamp time and 231 s longer CPB time for every 1 mm smaller aortic valve diameter.CONCLUSIONSThe anatomical variables are associated with the operative times in minimally invasive aortic valve replacement with sutureless valves. Considering this association, preplanning the procedure is recommended.     

Effects of different BP management strategies on postoperative delirium in elderly patients undergoing hip replacement: A single center randomized controlled trial

Study objectivePostoperative delirium (POD) is a common after hip replacement. Intraoperative blood pressure management may affect postoperative delirium. The aim of this study was to compare the effects of different blood pressure management strategies on POD.DesignA single center randomized controlled trial.SettingThe Second Hospital of Anhui Medical University, Hefei, China.PatientsA total of 150 patients aged 65–80 years underwent hip arthroplasty.InterventionsA random number table was used to divide the patients into three groups: mean blood pressure (MAP) was maintained from 10% to 20% below the baseline (group D), MAP was maintained from baseline to 10% below the baseline (group M), and MAP was maintained from baseline to 10% above the baseline (group H).MeasurementsThe primary endpoint was POD at 1–3 days. The secondary endpoint was the intraoperative MAP and regional cerebral oxygen saturation (rSO₂) value, MAP, Visual Analogue Scale (VAS score) 1–3 days after surgery, the lengths of post anesthesia care unit (PACU) stay and hospital stay and emergence agitation were recorded.Main resultsPatients in group H showed a lower incidence of POD on the first day than those in groups D and M (22% and 16% vs 4%; P = 0.031). There is no difference of incidence of POD on the 2rd and 3rd day postoperatively. Patients in group H received a higher MAP as well as rSO₂ during the operation compared the other two groups (P < 0.05). Compared with groups D and M, emergence agitation was significantly reduced (P = 0.029) and the lengths of PACU stay (P = 0.018) and hospital stay (P = 0.008) were shortened in group H.ConclusionsMaintenance of intraoperative blood pressure from baseline to 10% above the baseline helps to reduce the incidence of POD and emergence agitation and shorten the lengths of PACU stay and hospital stay, and it may be related to increased rSO₂ during the operation.     

Efficacy of maintaining low-tidal volume mechanical ventilation as compared to resting lung strategy during coronary artery bypass graft cardiopulmonary bypass surgery: A post-hoc analysis of the MECANO trial

Study objectiveTo compare a low-tidal-volume with positive end-expiratory pressure strategy (VENT strategy) to a resting-lung-strategy (i.e., no-ventilation (noV) strategy) during cardiopulmonary bypass for coronary artery bypass graft surgery on the incidence of postoperative pulmonary complications.DesignPost-hoc analysis of the MECANO trial which was a prospective single-center, blind, randomized, parallel-group controlled trial.SettingTertiary care cardiac surgery center.PatientsPatients who underwent isolated on-pump coronary bypass surgery were randomized either to VENT or noV group.InterventionDuring the cardiopulmonary bypass phase of the cardiac surgery procedure, mechanical ventilation in the VENT group consisted of a tidal volume of 3 mL/kg, a respiratory rate of 5 per minute and a positive end-expiratory pressure of 5 cmH₂O. Patients in the noV group received no ventilation during this phase.MeasurementsPrimary composite outcome combining death, early respiratory failure, ventilation support beyond day 2 and reintubation.Main resultsIn this post-hoc analysis, we retained 725 patients who underwent isolated CABG surgery, from the 1501 patients included in the original study. There were 352 in the VENT group and 373 patients in the noV group. Post-hoc comparison yielded no differences in baseline characteristics between these two groups. The primary outcome occurred less frequently in the VENT group than in the noV group, with 44 (12.5%) and 76 (20.4%) respectively (odds-ratio (OR) = 0.56 (0.37–0.84), p = 0.004). There were fewer early respiratory dysfunctions and prolonged respiratory support in the VENT group (respectively, OR = 0.34 (0.12–0.96) p = 0.033 and OR = 0.51 (0.27–0.94) p = 0.029). Complications related to mechanical ventilation were similar in the two groups.ConclusionsIn this post-hoc analysis, maintaining low-tidal ventilation compared to a resting-lung strategy was associated with fewer pulmonary postoperative complications in patients who underwent isolated CABG procedures.     

An increase in macrophage migration inhibitory factor release in patients with cardiopulmonary bypass surgery

To determine the macrophage migration inhibitory factor (MIF) responses to cardiopulmonary bypass (CPB) surgery as well as to investigate their roles in predicting patient outcome, a prospective, observational, pilot study was performed. Thirty patients undergoing cardiovascular surgery with CPB received 10 mg/kg betamethasone immediately before the CPB. Ten normal healthy volunteers served as control subjects. Blood samples were serially obtained for 24 h and assayed for MIF, cortisol, and tumor necrosis factor α (TNF-α). TNF-α release could not be detected during the study period. Compared with both the control and baseline values, the MIF and cortisol levels were elevated before CPB and peaked at the end of CPB (57.5 ± 4.8 ng/ml, P < 0.0001), and at the end of the surgery (507.7 ± 44.1 nmol/l, P < 0.0001), respectively. Peak MIF levels correlated with aortic cross-clamp time (r ² = 0.183, P = 0.0182, n = 30), but did not show a significant correlation with peak cortisol levels. The levels of MIF tended to be 40%–50% higher during CPB in patients with longer intensive care unit (ICU) stays and in those with organ dysfunction than in those with short ICU stays and no organ dysfunction. All patients were discharged from the ICU. In conclusion, our findings demonstrate that MIF production occurs in patients with CPB surgery. When high-dose steroids are administered, high MIF levels were found to only slightly affect the patient morbidity and outcome after CPB surgery. Received: August 17, 1999 / Accepted: March 24, 2000     

Oxidative stress during coronary artery bypass operations: importance of surgical trauma and drug treatment

OBJECTIVE: To investigate oxidative stress and myocardial injury at different stages of coronary artery bypass grafting (CABG). DESIGN: Twenty patients underwent CABG with use of cardiopulmonary bypass (CPB) and with intermittent sampling of plasma and urine. Main markers were: 8-iso-PGF2alpha (oxidative stress); troponin T (myocardial injury); and 15-keto-dihydro-PGF2alpha and hsCRP (inflammation). RESULTS: Plasma 8-iso-PGF2alpha increased after start of surgery, but there was no further rise during CPB or after aortic cross-clamp release and no significant myocardial arterio-venous differences. An increase in troponin T was seen early after the operation, but no relationship was established between 8-iso-PGF2alpha and troponin T. 8-iso-PGF2alpha levels were elevated by preoperative withdrawal of acetylsalicylic acid (ASA) but reduced by intraoperative use of heparin. 15-keto-dihydro-PGF2alpha was elevated during operation and hsCRP following operation. CONCLUSIONS: In the present study oxidative stress was multifactorial in origin with main impacts from surgical trauma, less from CPB and little if any from myocardial ischemia-reperfusion events. In addition, cardiovascular drugs in common use like ASA and heparin seemed to influence the pro- and antioxidant balance, a finding that has to be confirmed in future studies.     

Correlação entre saturação venosa central de oxigênio perioperatória e mortalidade em cirurgia cardíaca: estudo prospectivo observacional

BackgroundCardiac surgery can produce persistent deficit in the ratio of Oxygen Delivery (DO₂) to Oxygen Consumption (VO₂). Central venous oxygen Saturation (ScvO₂) is an accessible and indirect measure of DO₂/VO₂ ratio.ObjectiveTo monitor perioperative ScvO₂ and assess its correlation with mortality during cardiac surgery.MethodsThis prospective observational study evaluated 273 patients undergoing cardiac surgery. Blood gas samples were collected to measure ScvO₂ at three time points: T0 (after anesthetic induction), T1 (end of surgery), and T2 (24 hours after surgery). The patients were divided into two groups (survivors and nonsurvivors). The following outcomes were analyzed: intrahospital mortality, length of Intensive Care Unit (ICU) and hospital stay (LOS), and variation in ScvO₂.ResultsOf the 273 patients, 251 (92%) survived and 22 (8%) did not. There was a significant perioperative reduction of ScvO₂ in both survivors (T0 = 78% ± 8.1%, T1 = 75.4% ± 7.5%, and T2 = 68.5% ± 9%; p < 0.001) and nonsurvivors (T0 = 74.4% ± 8.7%, T1 = 75.4% ± 7.7%, and T2 = 66.7% ± 13.1%; p < 0.001). At T0, the percentage of patients with ScvO₂ < 70% was greater in the nonsurvivor group (31.8% vs. 13.1%; p = 0.046) and the multiple logistic regression showed that ScvO₂ is an independent risk factor associated with death, OR = 2.94 (95% CI 1.10 − 7.89) (p = 0.032). The length of ICU and LOS were 3.6 ± 3.1 and 7.4 ± 6.0 days respectively and was not significantly associated with ScvO₂.ConclusionsEarly intraoperative ScvO₂ < 70% indicated a higher risk of death. A perioperative reduction of ScvO₂ was observed in patients undergoing cardiac surgery, with high intraoperative and lower postoperative levels.     

The impact of aortic manipulation on neurologic outcomes after coronary artery bypass surgery: a risk-adjusted study

Background

Cerebral embolization of atherosclerotic plaque debris caused by aortic manipulation during conventional coronary artery bypass grafting (CABG) is a major mechanism of postoperative cerebrovascular accidents (CVA). Off-pump CABG (OPCABG) reduces stroke rates by minimizing aortic manipulation. Consequently, the effect of different levels of aortic manipulation on neurologic outcomes after CABG surgery was examined.

Methods

From January 1998 to June 2002, 7,272 patients underwent isolated CABG surgery through three levels of aortic manipulation: full plus tangential (side-biting) aortic clamp application (on-pump surgery; n = 4,269), only tangential aortic clamp application (OPCABG surgery; n = 2,527) or an “aortic no-touch” technique (OPCABG surgery; n = 476). A risk-adjusted logistic regression analysis was performed to establish the likelihood of postoperative stroke with each technique. Preoperative risk factors for stroke from the literature, and those found significant in a univariable model were used.

Results

A significant association for postoperative stroke correspondingly increasing with the extent of aortic manipulation was demonstrated by the univariable analysis (CVA incidence respectively increasing from 0.8% to 1.6% to a maximum of 2.2%, p < 0.01). In the logistic regression model, patients who had a full and a tangential aortic clamp applied were 1.8 times more likely to have a stroke versus those without any aortic manipulation (95% confidence interval: 1.15 to 2.74, p < 0.01) and 1.7 times more likely to develop a postoperative stroke than those with only a tangential aortic clamp applied (95% confidence interval: 1.11 to 2.48, p < 0.01).

Conclusions

Aortic manipulation during CABG is a contributing mechanism for postoperative stroke. The incidence of postoperative stroke increases with increased levels of aortic manipulation.     

Characteristic changes in cerebral perfusion during on-pump and off-pump coronary artery surgery

Objective: We investigated the cerebral perfusion status during on-pump or off-pump coronary artery bypass grafting (CABG). Methods: We monitored somatosensory evoked potential (SEP) and regional cerebral oxygen saturation (rSO₂) as parameters of cerebral perfusion in an on-pump group (n=10) and an off-pump group (n=16). The percent changes from control values were calculated before, during, and after aortic clamping, and after weaning from cardiopulmonary bypass, in the on-pump group. In the off-pump group, these were calculated before, during, and after heart displacement for distal anastomosis. Results: In the on-pump group, the amplitudes of the SEP were significantly enhanced during and after aortic cross-clamping and were associated with a significant decrease in rSO₂. Latency was prolonged immediately after aortic cross-clamping, but was shortened afterwards. There was little change in these parameters throughout the operation, in the off-pump group. Conclusions: Cerebral perfusion remains stable during off-pump CABG. The etiology of a simultaneous increase in SEP amplitude and decrease in rSO₂ during the rewarming period in the on-pump group requires further investigation.