Preoperative intra-aortic balloon pump inserted in acute myocardial infarction patients without cardiogenic shock undergoing surgical coronary revascularization.

OBJECTIVES: The benefit of preoperative intra-aortic balloon pump implantation in high-risk cardiac surgery patients is still debated. The role of preoperative intra-aortic balloon pump insertion in acute myocardial infarction patients without cardiogenic shock undergoing off-pump coronary artery bypass grafting remains unknown. This study aimed to determine the efficacy and safety of the preoperative intra-aortic balloon pump insertion in those patients undergoing off-pump coronary artery bypass grafting. METHODS: A total of 421 consecutive acute myocardial infarction patients without cardiogenic shock who underwent isolated off-pump coronary artery bypass grafting were enrolled in this retrospective observational propensity score-matched analysis study. Patients who received intra-aortic balloon pump before off-pump coronary artery bypass grafting (the intra-aortic balloon pump group, n = 157) were compared with those who had not (control group, n = 264). The 30-day postoperative survival, postoperative complications, and postoperative hospital length of stay were compared between the two groups. RESULTS: A total of 99 pairs of patients were matched. The preoperative intra-aortic balloon pump did not show a 30-day postoperative survival benefit compared with the control group (hazard ratio, 0.9; 95% confidence interval, 0.2-4.2; p = 0.92). Patients with preoperative intra-aortic balloon pump were more likely to have shorter postoperative lengths of stay (8 (6-11) days vs. 10 (6-15) days, p = 0.02) and decreased total days in the hospital (median days: 18.2 vs. 21.8, p = 0.02) compared to patients without balloon pumps. CONCLUSION: Preoperative intra-aortic balloon pump insertion in acute myocardial infarction patients without cardiogenic shock undergoing off-pump coronary artery bypass grafting improved convalescence as shown by significantly shorter postoperative lengths of hospital stay.

Veno-Arterial Extracorporeal Membrane Oxygenation Support in Patients Undergoing Aortic Surgery.

Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) is an option for mechanical support for patients with postcardiotomy cardiogenic shock (PCS). However, the use of VA-ECMO in patients suffering from aortic disease with PCS has not been greatly reported. This is a retrospective review of adult patients undergoing aortic surgery who received VA-ECMO support to treat refractory PCS from August 2009 to May 2016. A total of 36 patients who underwent aortic surgery with VA-ECMO support for refractory PCS were included. Preoperative, perioperative, and postoperative variables were assessed and analyzed for possible correlation with in-hospital mortality. After a mean duration of 3.6 ± 2.9 days, 24 patients (67%) were weaned off VA-ECMO, and 18 patients (50%) were discharged from the hospital. The overall in-hospital mortality was 50%. The main cause of death was multiple organ dysfunction. The survivors had a lower level of preoperative creatine kinase-MB (CK-MB), a higher rate of antegrade cannulation, and a lower lactate level at 12 h, respectively. Relevant factors for in-hospital mortality were retrograde-flow cannulation (odds ratio [OR], 2.49), peak lactate levels greater than 20 mmol/L (OR, 5.0), and preoperative CK-MB greater than 100 IU/L (OR, 6.40). Antegrade cannulation may provide better perfusion and should be emphasized to improve outcomes. Additionally, levels of peak serum lactate and preoperative CK-MB may be relevant factors for in-hospital mortality in aortic patients with PCS.

Superior vena cava drainage improves upper body oxygenation during veno-arterial extracorporeal membrane oxygenation in sheep.

INTRODUCTION: Differential hypoxia is a pivotal problem in patients with femoral veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) support. Despite recognition of differential hypoxia and attempts to deliver more oxygenated blood to the upper body, the mechanism of differential hypoxia as well as prevention strategies have not been well investigated. METHODS: We used a sheep model of acute respiratory failure that was supported with femoral VA ECMO from the inferior vena cava to the femoral artery (IVC-FA), ECMO from the superior vena cava to the FA (SVC-FA), ECMO from the IVC to the carotid artery (IVC-CA) and ECMO with an additional return cannula to the internal jugular vein based on the femoral VA ECMO (FA-IJV). Angiography and blood gas analyses were performed. RESULTS: With IVC-FA, blood oxygen saturation (SO2) of the IVC (83.6 ± 0.8%) was higher than that of the SVC (40.3 ± 1.0%). Oxygen-rich blood was drained back to the ECMO circuit and poorly oxygenated blood in the SVC entered the right atrium (RA). SVC-FA achieved oxygen-rich blood return from the IVC to the RA without shifting the arterial cannulation. Subsequently, SO2 of the SVC and the pulmonary artery increased (70.4 ± 1.0% and 73.4 ± 1.1%, respectively). Compared with IVC-FA, a lesser difference in venous oxygen return and attenuated differential hypoxia were observed with IVC-CA and FA-IJV. CONCLUSIONS: Differential venous oxygen return is a key factor in the etiology of differential hypoxia in VA ECMO. With knowledge of this mechanism, we can apply better cannula configurations in clinical practice.

Effects of intra-aortic balloon pump on cerebral blood flow during peripheral venoarterial extracorporeal membrane oxygenation support.

BACKGROUND: The addition of an intra-aortic balloon pump (IABP) during peripheral venoarterial extracorporeal membrane oxygenation (VA ECMO) support has been shown to improve coronary bypass graft flows and cardiac function in refractory cardiogenic shock after cardiac surgery. The purpose of this study was to evaluate the impact of additional IABP support on the cerebral blood flow (CBF) in patients with peripheral VA ECMO following cardiac procedures. METHODS: Twelve patients (mean age 60.40±9.80 years) received VA ECMO combined with IABP support for postcardiotomy cardiogenic shock after coronary artery bypass grafting. The mean CBF in the bilateral middle cerebral arteries was measured with and without IABP counterpulsation by transcranial Doppler. The patients provided their control values. The mean CBF data were divided into two groups (pulsatile pressure greater than 10 mmHg, P group; pulsatile pressure less than 10 mmHg, N group) based on whether the patients experienced cardiac stun. The mean cerebral blood flow in VA ECMO (IABP turned off) alone and VA ECMO with IABP support were compared using the paired t test. RESULTS: All of the patients were successfully weaned from VA ECMO, and eight patients survived to discharge. The addition of IABP to VA ECMO did not change the mean CBF (251.47±79.28 ml/min vs. 251.30±79.47 ml/min, P=0.96). The mean CBF was higher in VA ECMO alone than in VA ECMO combined with IABP support in the N group (257.68±97.21 ml/min vs. 239.47±95.60, P=0.00). The addition of IABP to VA ECMO support increased the mean CBF values significantly compared with VA ECMO alone (261.68±82.45 ml/min vs. 244.43±45.85 ml/min, P=0.00) in the P group. CONCLUSION: These results demonstrate that an IABP significantly changes the CBF during peripheral VA ECMO, depending on the antegrade blood flow by spontaneous cardiac function. The addition of an IABP to VA ECMO support decreased the CBF during cardiac stun, and it increased CBF without cardiac stun.

Comparison of low molecular weight hydroxyethyl starch and human albumin as priming solutions in children undergoing cardiac surgery.

Human albumin is the conventional cardiopulmonary bypass circuit primer. However, it has high manufacturing costs. Crystalloid and colloid solutions have been developed as alternatives, including a new generation of non-ionic hydroxyethyl starch (HES). The efficacy of hydroxyethyl starch with a 130 molecular weight and substitution degree of 0.4 (hydroxyethyl starch 130/0.4) was compared with human albumin for use in cardiopulmonary bypass surgery in American Society of Anesthesiologists' grade I-II pediatric congenital heart disease patients. Efficacy was evaluated by comparing perioperative hemodynamic parameters, including plasma colloid osmotic pressure, renal function, blood loss, allogeneic blood volumes and plasma volume substitution. The hydroxyethyl starch group exhibited significantly higher preoperative colloid osmotic pressure (p<0.01) and significantly lower operative renal function and postoperative allogeneic blood volumes than the human albumin group. No significant differences were observed in serum creatinine, glucose, hematocrit or lactic acid levels (p>0.05). Our results indicate that hydroxyethyl starch may be a viable alternative to human albumin in pediatric patients undergoing relatively simple cardiopulmonary bypass surgeries.

Clinical evaluation of five commercially available adult oxygenators in terms of pressure drop during normothermic and hypothermic cardiopulmonary bypass.

BACKGROUND: It is well documented that trans-membrane pressure drop (TMPD) of hollow-fiber membrane oxygenators (HFMO) may lead to hemolysis, damage to platelets, and systemic inflammatory response. The purpose of this study was to evaluate five commercially available adult oxygenators in terms of pressure drop during normothermic and hypothermic cardiopulmonary bypass (CPB). MATERIALS AND METHODS: In a clinical setting, 5 different adult HFMOs were tested in terms of TMPDs. Forty patients scheduled for cardiac surgery were enrolled in the study and were divided into 5 groups according to the type of oxygenator used during CPB: group J (Maquet Quardox n=8), group A (Affinity NT n=8), group P (Polystan Safe Maxi n=8), group T (Terumo Capiox SX 18 n=8) and group C (COBE APEX-TM n=8). Clinical parameters were collected during CPB, including mean arterial pressure (MAP), pump flow, temperature, hematocrit, duration of CPB, cross-clamp time and bypass time. TMPDs of pre-oxygenator and post-oxygenator pressures were recorded at the start of systemic cooling (T1), 10 min after stable hypothermia at 30 degrees C (T2), and at termination of rewarming before the end of CPB (T3). RESULTS: There were no significant differences among the 5 groups in pump-flow rate, temperature, hematocrit, and mean arterial pressure during CPB. TMPDs of group J were the lowest at different time-points (T1, 30.71 +/- 8.42mmHg; T2, 25.71 +/- 5.41 mmHg; T3, 27.42 +/- 13.01 mmHg). Compared to the other 3 groups (P, C and T groups), TMPDs of groups J and A at various time-points were lower (J group compared with the other three groups (p<0.001). Although TMPDs in groups A, P and T during hypothermia were higher than during normothermia and post-rewarming, there was no significant statistical difference (p> 0.05). CONCLUSIONS: These results suggest that the HFMOs in groups J and A produced significantly lower TMPDs and pre- and post-oxygenator extracorporeal circuit pressures during normothermic and hypothermic CPB.

Beneficial effect of preventative intra-aortic balloon pumping in high-risk patients undergoing first-time coronary artery bypass grafting-a single center experience.

Although intra-aortic balloon pumping (IABP) has been used widely as a routine cardiac assist device for perioperative support in coronary artery bypass grafting (CABG), the optimal timing for high-risk patients undergoing first-time CABG using IABP is unknown. The purpose of this investigation is to compare preoperative and preventative IABP insertion with intraoperative or postoperative obligatory IABP insertion in high-risk patients undergoing first-time CABG. We reviewed our IABP patients' database from 2002 to 2007; there were 311 CABG patients who received IABP treatment perioperatively. Of 311 cases, 41 high-risk patients who had first-time on-pump or off-pump CABG (presenting with three or more of the following criteria: left ventricular ejection fraction less than 0.45, unstable angina, CABG combined with aneurysmectomy, or left main stenosis greater than 70%) entered the study. We compared perioperatively the clinical results of 20 patients who underwent preoperative IABP placement (Group 1) with 21 patients who had obligatory IABP placement intraoperatively or postoperatively during CABG (Group 2). There were no differences in preoperative risk factors, except left ventricular aneurysm resection, between the two groups. There were no differences in indications for high-risk patients between the two groups. The mean number of grafts was similar. There were no significant differences in the need for inotropes, or in cerebrovascular, gastrointestinal, renal, and infective complications postoperatively. There were no IABP-related complications in either group. Major adverse cardiac event (severe hypotension and/or shock, myocardial infarction, and severe hemodynamic instability) was higher in Group 2 (14 [66.4%] vs. 1 [5%], P < 0.0001) during surgery. The time of IABP pumping in Group 1 was shorter than in Group 2 (72.5 +/- 28.9 h vs. 97.5 +/- 47.7 h, P < 0.05). The duration of ventilation and intensive care unit stay in Group 1 was significantly shorter than in Group 2, respectively (22.0 +/- 1.6 h vs. 39.6 +/- 2.1 h, P < 0.01 and 58.0 +/- 1.5 h vs. 98.5 +/- 1.9 h, P < 0.005). There were no differences in mortality between the two groups (n = 1 in Group 1 and n = 3 in Group 2). Preoperative and preventative insertion of IABP can be performed safely in selected high-risk patients undergoing CABG, with results comparable to those in patients who received obligatory IABP intraoperatively and postoperatively. Therefore, earlier IABP support as part of surgical strategy may help to improve the outcome in high-risk first-time CABG patients.

Effect of increasing mean arterial blood pressure on microcirculation in patients with cardiogenic shock supported by extracorporeal membrane oxygenation.

BACKGROUND: Little is known about the effect of mean arterial blood pressure (MAP) augmentation on the microcirculation in cardiogenic-shock patients with peripheral veno-arterial extracorporeal membrane oxygenation (ECMO) support. We investigated the effect of increasing MAP on the microcirculation in cardiogenic-shock patients with ECMO support. METHODS: A single-center prospective observational study under taken in ICU patients undergoing ECMO support for post-cardiotomy cardiogenic shock was carried out. Patients with MAP <60 mmHg treated with ECMO support were the study cohort. Inotropic and vasopressor agents (dopamine, dobutamine, norepinephrine or epinephrine) were administered to maintain the MAP at 60-90 mmHg. Hemodynamic and microcirculatory data were obtained at a baseline MAP of <60 mmHg and 1 h after target MAP was reached. As parameters of microcirculation, we measured thenar eminence tissue oxygenation (StO2) and its change during the vessel obstruction test and cerebral tissue oxygenation (rSO2) with near-infrared spectroscopy. RESULTS: Seventeen patients were enrolled in the study. MAP of all patients increased and reached predefined therapeutic targets (52 [50-54.5] vs.74 [70-78.5] mmHg; p < 0.001). To obtain these targets, doses of inotropic agents were increased (inotrope score increased from 14 [15.5-28] µg/kg/min; p < 0.001). No obvious changes were observed in thenarmuscleStO2 and cerebral rSO2. Thenar muscle StO2 desaturation slope and resaturation slopes during the vessel obstruction test were also unchanged. CONCLUSIONS: Increasing MAP from <60 mmHg to 60-90 mmHg did not affect microcirculation variables in cardiogenic-shock patients with ECMO support.

Integrated antimicrobial and antifouling ultrafiltration membrane by surface grafting PEO and N-chloramine functional groups.

Ultrafiltration membranes with integrated antimicrobial and antifouling properties were fabricated using an engineering thermoplastic (carboxylated cardopoly(aryl ether ketone, PEK-COOH). Different molecular weights of PEO (Mw: 120, 350, 550) were grafted to the PEK-COOH membrane surface via EDC/NHS methodology. N-chloramine modified membranes then were prepared by simple exposure to dilute sodium hypochlorite solution. The surface grafting processes were all performed in water (i.e. without organic solvent). With this surface modification, the hydrophilicity of membranes improved significantly and the pure water flux increased compared to the unmodified PEK-COOH membrane. Furthermore, the PEO and N-chloramine modified membranes were resistant not only to both protein adsorption and bacterial adhesion, but also to microbial proliferation. The results of this work suggest that PEO and N-chloramine modified membranes are promising as fouling-resistant membranes.

Preoperative intra-aortic balloon pump improves the clinical outcomes of off-pump coronary artery bypass grafting in left ventricular dysfunction patients.

Severe left ventricular (LV) dysfunction patients undergoing off-pump coronary artery bypass grafting (OPCAB) are often associated with a higher mortality. The efficacy and safety of the preoperative prophylactic intra-aortic balloon pump (IABP) insertion is not well established. 416 consecutive patients with severe LV dysfunction (ejection fraction ≤35%) undergoing isolated OPCAB were enrolled in a retrospective observational study. 191 patients was enrolled in the IABP group; the remaining 225 patients was in control group. A total of 129 pairs of patients were propensity-score matched. No significant differences in demographic and preoperative risk factors were found between the two groups. The postoperative 30-day mortality occurred more frequently in the control group compared with the IABP group (8.5% vs. 1.6%, p = 0.02). There was a significant reduction of low cardiac output syndrome in the IABP group compared with the control group (14% vs. 6.2%, p = 0.04). Prolonged mechanical ventilation (≥48 h) occurred more frequently in the control group (34.9% vs. 20.9%, p = 0.02). IABP also decreased the postoperative length of stay. Preoperative IABP was associated with a lower 30-day mortality, suggesting that it is effective in patients with severe LV dysfunction undergoing OPCAB.

Extracorporeal cardiopulmonary resuscitation for adult patients who underwent post-cardiac surgery.

BACKGROUND: Refractory cardiac arrest (CA) occasionally develops in patients after cardiac surgery. OBJECTIVE: To examine the clinical outcomes of extracorporeal cardiopulmonary resuscitation (ECPR) in adult patients with post-cardiotomy CA. METHODS: This was a retrospective study of the 9-year experience (from January 2004 to May 2012) of the Beijing Anzhen Hospital with ECPR in adult patients with post-cardiotomy CA. At this hospital, a dedicated ECPR team is available 24/7 for emergency cases requiring ECPR. Demographic data, biochemical data, survival, morbidity, and complications were examined before, during, and after ECPR. Outcomes were compared between survivors and non-survivors. RESULTS: Twenty-four adult patients (19 men and 5 women; mean age: 59.3 ± 11.9 years) received ECPR support for post-cardiotomy CA. The cardiac surgery procedures included coronary artery bypass grafting (n = 20, 83.3 %), valvular surgery alone (n = 2, 8.3 %), and correction of congenital heart defects (n = 2, 8.3 %). The mean extracorporeal membrane oxygenation (ECMO) duration was 115.23 ± 70.17 h. Twenty-one patients received ECPR after intra-aortic balloon pump, and three patients received ECPR directly. The main cause of mortality was multiple system organ failure (n = 12, 50.0 %). Approximately one-half of non-survivors had severe neurologic impairments. Among 16 patients who were weaned off ECMO support, eight patients survived to hospital discharge. CONCLUSIONS: ECPR can be effective for partial cardiopulmonary support to resuscitate adult patients suffering from refractory CA after cardiac surgery. Improvement in outcomes of patients who received ECPR requires a multidisciplinary approach to protect organ function and limit organ injury before and during cardiac support.

The myocardial protective effect of adenosine as an adjunct to intermittent blood cardioplegia during open heart surgery.

BACKGROUND: Although adenosine (ADO) has been shown to have beneficial effects against tissue injury after myocardial ischaemia, the controversy still remains regarding the optimal timing, dose, temperature, method of ADO administration and duration of exposure to the drug. This study investigates the cardioprotective effect of exogenous ADO pretreatment as an adjunct to 1 mmol l(-1) ADO cold (12 degrees C) blood cardioplegia during heart valve replacement surgery. MATERIALS AND METHODS: Thirty patients with rheumatic heart valve disease undergoing heart valve replacement operations were randomly assigned to two groups: group C (n=15) and group A (n=15). Patients in group C were the control group and received antegrade cold (12 degrees C) high-potassium ([K(+)]=20 mol l(-1)) institute blood cardioplegia. The patients in group A received 10-min 100 microgkg(-1)min(-1) ADO pretreatment before application of the aortic cross-clamp and antegrade 1 mmol l(-1) adenosine high-potassium ([K(+)]=20 mol l(-1)) cold (12 degrees C) blood cardioplegia. Clinical outcomes were observed before, during and after the operation. Plasma level markers of myocardial damage: cardiac Troponin I (cTnI), creatine kinase (CK-MB) and inflammatory factors (interleukin (IL)-6 and IL-8) were obtained from serial venous blood samples after induction, 5 min after cross-clamp of aorta, 10 min after clamp-off, 1h after return to ICU and postoperatively 24 h and 48 h. Right atrial samples were harvested before cross-clamp and after clamp-off. RESULTS: Heart valve replacement was successful in all patients. There were no differences regarding operative parameters in the two groups. Time to arrest (during cardiolegia perfusion electrocardiography (ECG) change to a line) was shorter in group A compared to group C (19.9+/-4.6s vs 29.3+/-10.6s; p=0.03). Group A also had lower cTnI and IL-8 levels (p=0.03) at 10 min after aortic declamping, and lower IL-6 (p=0.04) at 24h postoperatively as well. Ultrastructural changes were slighter in group A than group C after clamp-off. Compared to group C, post-reperfusion biopsies in group A displayed only slight overall ultrastructural changes, and scored significantly better on mitochondrial damage (group A 2.23+/-0.65 vs group C 2.85+/-0.66) (p=0.04). CONCLUSION: Compared with simple cold blood cardioplegia in heart valve replacement patients, ADO pretreatment as an adjunct to 1 mmol l(-1) ADO cold blood cardioplegia may reduce cTnI, IL-6 and IL-8 release, resulting in reduced myocardial injury in ultrastructure after surgery.