Application of specific extracorporeal removal of low density lipoprotein in familial hypercholesterolaemia

A highly selective method for the removal of apolipoprotein-B-containing serum lipoproteins (low density lipoproteins [LDL] and very-low-density lipoproteins [VLDL]) from hypercholesterolaemic patients by immunoadsorption in an extracorporeal system consists of separation of plasma from the blood cells by a blood-separation centrifuge, followed by the selective adsorption of LDL from the plasma effluent, from which high-density lipoproteins (HDL) and other plasma proteins are not removed, is returned to the patient with the blood cells. Three patients with familial hypercholesterolaemia, one homozygous and two heterozygous, were treated repeatedly during a period of 9 months. No undesirable side-effects or changes in clinical, chemical, haematological, or immunological parameters have yet been observed. The new procedure has several advantages over treatments currently used; it is non-invasive, more specific, and less costly and lowers LDL to a greater degree.

Coating-techniques to improve the hemocompatibility of artificial devices used for extracorporeal circulation

OBJECTIVE

Extracorporeal circulation procedures have been shown to induce complement and leukocyte activation, release of endotoxin and inflammatory mediators, including cytokines, nitric oxide, oxygen free radicals, and platelet activating factors. The contact between the blood and the various artificial surfaces of the extracorporeal system results in an unspecific post-perfusion syndrome. For diminishing these negative side effects several coating-techniques have been developed to create devices with improved hemocompatibility.

METHODS

This review deals with the current knowledge of heparin-coated and otherwise surface-modified perfusion systems. The pathway how heparin-coated surfaces work is discussed and techniques for surface-coatings, both clinically introduced as well as newly developed are presented.

RESULTS

Numerous clinical studies compared heparin-coated versus non-coated circuits. Heparin-bonded devices showed lessened humoral and cellular activation, in particular a reduced complement activation with a reduced inflammatory post-perfusion syndrome. Also platelet protection and more favorable post-operative lung function are of particular note. Recent clinical trials demonstrated shortened hospital stays, less drainage bleeding, and reduced cerebral complications using heparin-coated oxygenation systems. The diminished expression of the leukocyte adhesion molecules CD 11b/c in CBAS devices points to a decreased activation of neutrophils. In addition, one research group found a reduced production of oxygen radicals. Heparin-bonding minimizes oxygenator failure by a significant reduced pressure gradient across the oxygenator, probably caused by decreased fibrin and platelet deposition at the hollow fiber surfaces. A meta analysis examined the impact of heparin-bonded systems on clinical outcomes and resulting costs. Using heparin-bonded circuits led to total cost savings from US $1000 to 3000. Several authors demonstrated reduced blood loss and better clinical outcome by reduction of systemic heparinization and the employment of heparin-coated devices.

CONCLUSION

Above and beyond the long-term applications, routine heart operations have also markedly begun to utilize heparin-coated devices. This trend will assuredly continue in the coming years and is an important step toward higher hemocompatibility of blood-contacting surfaces in the ECC device. Heparin-coatings are merely the beginning of improved hemocompatibility for all materials that come into contact with human blood or tissues. Intelligent materials with almost completely physiological surfaces will be at the surgeon's disposal within the next few years.

Antegrade cerebral perfusion with cold blood: a 13-year experience

BACKGROUND

In 1986 we introduced the technique of antegrade selective perfusion of the brain with cold blood during surgery of the aortic arch.

METHODS

Between January 1984 and March 1998, 171 patients (118 males and 53 females) aged 25 to 83 years (mean 56.5 +/- 17), underwent replacement of the transverse aortic arch with the aid of cold blood antegrade selective perfusion. One hundred twenty two patients (71.3%) with chronic lesions were operated on electively; 49 patients (28.6%) were operated on urgently for acute aortic dissection (42 patients) or for a ruptured chronic aneurysm (7 patients). Fifty-one patients (29.8%) had previously undergone a surgical procedure on the thoracic aorta. Mean duration of cardiopulmonary bypass was 121 minutes (range: 65-248); mean duration of cerebral perfusion was 60 minutes (range: 15-90), and mean duration of systemic circulatory arrest circuit was 32 minutes (range: 10-57). The electroencephalogram, routinely recorded, showed disappearance of electrical activity in a mean of 9 minutes (range: 3-16) initial return of electrical activity after a mean of 12 minutes (range: 1-35) and normalization in a mean time of 66 minutes.

RESULTS

All patients but 7 (4%) showed signs of normal awakening within 8 hours postoperatively. Six patients (3.5%) had fatal neurologic complications, and 16 patients (9.3%) had a non-fatal neurologic complications. Twenty-nine patients (16.9%) died during the postoperative hospital course. There was a significant difference between patients aged less than 60 years (9%) and patients older than 60 years (mortality rate 26.4%, p < 0.02). There was also a significant difference between patients undergoing an isolated replacement of the arch, and those in whom the replacement was extended to the descending aorta in whom mortality was 36.4% (chi2, p < 0.02). Lesion and gender had no significant influence on the outcome of the patients, nor had the duration of cardiopulmonary bypass, circulatory arrest, and cerebral perfusion. In particular, no correlation could be established between the duration of cerebral perfusion and the occurrence of neurologic complications.

CONCLUSION

The clinical results obtained throughout this experience have demonstrated that selective antegrade cerebral perfusion with cold blood provides excellent protection during surgery of the transverse aortic arch. In addition, it avoids the use of deep hypothermia and prolonged cardiopulmonary bypass and does not limit the time allowed to perform the aortic repair. In our opinion it is the technique of choice, especially in frail patients or those requiring a long and difficult procedure.

Avoiding invasive mechanical ventilation by extracorporeal carbon dioxide removal in patients failing noninvasive ventilation

PURPOSE

To evaluate whether extracorporeal carbon dioxide removal by means of a pumpless extracorporeal lung-assist (PECLA) device could be an effective and safe alternative to invasive mechanical ventilation in patients with chronic pulmonary disease and acute hypercapnic ventilatory failure not responding to noninvasive ventilation (NIV).

METHODS

In this multicentre, retrospective study, 21 PECLA patients were compared with respect to survival and procedural outcomes to 21 matched controls with conventional invasive mechanical ventilation. Matching criteria were underlying diagnosis, age, Simplified Acute Physiology Score II and pH at ICU admission.

RESULTS

Of the 21 patients treated with PECLA, 19 (90 %) did not require intubation. Median PaCO(2) levels and pH in arterial blood prior to PECLA were 84.0 mmHg (54.2-131.0) and 7.28 (7.10-7.41), respectively. Within 24 h, median PaCO(2) levels and pH had significantly improved to 52.1 (33.0-70.1; p < 0.001) and 7.44 (7.27-7.56; p < 0.001), respectively. Two major and seven minor bleeding complications related to the device occurred. Further complications were one pseudoaneurysm and one heparin-induced thrombocytopenia type 2. Compared to the matched control group, there was a trend toward a shorter hospital length of stay in the PECLA group (adjusted p = 0.056). There was no group difference in the 28-day (24 % vs. 19 %, adjusted p = 0.845) or 6-month mortality (33 % vs. 33 %).

CONCLUSIONS

In this study the use of extracorporeal carbon dioxide removal allowed avoiding intubation and invasive mechanical ventilation in the majority of patients with acute on chronic respiratory failure not responding to NIV. Compared to conventional invasive ventilation, short- and long-term survivals were similar.

Successful extracorporeal porcine liver perfusion for 72 hr

BACKGROUND

Improvements in extracorporeal perfusion technology and the production of transgenic pigs resistant to hyperacute rejection have stimulated several groups to re-explore the possibility of supporting patients in hepatic failure with extracorporeal porcine livers. The success of organ transplantation has also stimulated interest in using extracorporeal perfusion as a means of organ preservation and resuscitation of organs from marginal donors. The present study describes a method by which livers can be maintained in a viable condition for a minimum of 72 hr of normothermic, extracorporeal perfusion.

METHODS

Five extracorporeal porcine liver perfusions were performed, each with a duration of 72 hr. Hepatectomy was performed, followed by cold preservation, cannulation of vessels, and initiation of perfusion with normothermic, oxygenated porcine blood. Organ viability was assessed by metabolic, synthetic, hemodynamic, and histologic parameters.

RESULTS

After 72 hr of normothermic, extracorporeal perfusion, the isolated livers demonstrated maintenance of normal physiological levels of pH and electrolytes. Continued hepatic protein synthesis (complement and factor V) was maintained throughout the perfusion. Hemodynamic parameters remained within normal physiological range. Histology demonstrated good preservation of the liver with no overall architectural change.

CONCLUSION

It is possible to maintain a liver in a viable condition for a minimum of 72 hr of extracorporeal perfusion. This technique has been developed primarily as a preclinical model of extracorporeal liver support with the intention of proceeding to a clinical trial in patients with fulminant liver failure. However, it also has potential applications in organ preservation or resuscitation before transplantation and in the experimental study of isolated liver physiology.

Four years' experience with a miniaturized extracorporeal circulation system and its influence on clinical outcome

It has been suggested that the morbidity associated with cardiopulmonary bypass can be attributed in part to the blood-material and blood-air interactions in the extracorporeal circulation (ECC). A recently introduced minimized ECC-system (MECC System) should be able to reduce these negative effects associated with ECC. A retrospective analysis was performed comprising 485 patients who were operated on for elective coronary artery bypass grafting (CABG) using the MECC System with intermittent antegrade warm blood cardioplegia (group 1) from January 2000 to February 2004. A control group consisted of 485 patients (group 2) undergoing elective CABG in the same period using a conventional ECC and cold crystalloid cardioplegia. There were no significant differences between the two groups in terms of the duration of intubation following surgery, the length of intensive care unit-stay and the total hospital stay. Although the 30-day mortality was similar between the two groups, the incidence of postoperative complications and the perioperative use of blood products were significantly higher in the control group compared to the MECC group. The MECC System may serve as an alternative and less invasive approach to conventional ECC.

Beating versus arrested heart revascularization: evaluation of myocardial function in a prospective randomized study

OBJECTIVE

Conventional coronary artery bypass grafting (CABG) is both safe and effective. Nevertheless, the use of cardiopulmonary bypass (CPB) and cardioplegic arrest are associated with several adverse effects. Over the last 2 years there has been a revival of interest in performing CABG on the beating heart. In this prospective randomized study we evaluated the efficacy and safety of on and off pump coronary revascularization on myocardial function.

METHODS

Eighty patients (65 males, mean age 61+/-9.7 years) undergoing first time CABG were prospectively randomized to: (i) conventional revascularization with CPB at normothermia and cardioplegic arrest with intermittent warm blood cardioplegia (on pump) or (ii) beating heart revascularization (off pump). Troponin I (Tn I) release was serially measured as a specific marker of myocardial damage. Haemodynamic measurements as well as inotropic requirement, incidence of arrhythmia and postoperative myocardial infarction were also recorded.

RESULTS

There were no significant differences between the two groups in terms of age, sex, extent of disease, left ventricular function and number of grafts. There were no deaths or intraoperative myocardial infarctions in either group. Tn I release was constantly lower in the off pump group and this was significant at 1, 4, 12 and 24 h postoperatively. Furthermore, in this group there was a significantly reduced incidence of arrhythmias. Inotropic requirements were less in the off pump group but this did not reach statistical significance.

CONCLUSION

These results suggest that off pump coronary revascularization is a safe and effective strategy for myocardial revascularization. Myocardial injury as assessed by Tn I release is also reduced when compared with conventional coronary revascularization with CPB and cardioplegic arrest.

Liver allotransplantation after extracorporeal hepatic support with transgenic (hCD55/hCD59) porcine livers: clinical results and lack of pig-to-human transmission of the porcine endogenous retrovirus

BACKGROUND

Whole organ extracorporeal perfusion of a genetically modified humanized (transgenic) pig liver has been proposed as a technology that may sustain patients with severe liver failure while awaiting human liver transplantation.

METHODS

We report on two cases of successful extracorporeal perfusion of a transgenic pig liver in patients awaiting transplantation for fulminant hepatic failure. The pig livers used were transgenic for human CD55 (decay-accelerating factor) and human CD59. These transgenic modifications are designed to reduce or eliminate the hyperacute rejection inherent in pig-to-primate xenotransplants. We also report on the results of serial surveillance testing for presence of the porcine endogenous retrovirus (PoERV) in these two patients.

RESULTS

Extracorporeal perfusion in two patients was performed for 6.5 and 10 hr, respectively, followed by the successful transplantation of a human liver and resultant healthy patients (18 and 5 months later as of this writing). The porcine livers showed evidence of synthetic and secretory function (decreasing protime and bilirubin, bile production). Serial polymerase chain reaction analysis of these patients' peripheral blood mononuclear cells has failed to show presence of PoERV DNA sequences.

CONCLUSIONS

The CD55/CD59 transgenic porcine liver appears capable of safely "bridging" a patient to liver transplantation. Human PoERV infection from these livers has yet to be demonstrated.

Clinical extracorporeal hybrid liver support--phase I study with primary porcine liver cells

The objective of this study was to evaluate the feasibility and safety of a hybrid liver support system with extracorporeal plasma separation and bioreactor perfusion in patients with acute liver failure (ALF) who had already fulfilled the criteria for high urgency liver transplantation (LTx). Eight patients (one male, seven female) were treated in terms of bridging to transplantation. The mean age was 36.5 yr (range 20 to 58). Etiology of liver failure was drug-related in two patients, hepatitis B infection in three patients, and unknown for three patients. The bioreactors were charged with primary liver cells from specific pathogen-free pigs. Cell viability varied between 91 and 98%. Continuous liver support treatment over a period of 8 to 46 h (mean 27.3 h) was safely performed and well-tolerated by all patients. No complications associated with the therapy were observed during the follow-up period. Thrombocytopenia was considered to be an effect of the plasma separation. Subsequently, all patients were transplanted successfully and were observed over at least 3 yr with an organ and patient survival rate of 100%. Screening of patient's sera for antibodies specific for porcine endogenous retroviruses (PERVs) showed no reactivity--either prior to application of the system, or after extracorporeal treatment. The results encourage us to continue the development of the technology, and further studies appear to be justified. The bioreactor technology has been integrated into a modular extracorporeal liver support (MELS) system, combining biologic liver support with artificial detoxification technology.

Nitric oxide-releasing fumed silica particles: synthesis, characterization, and biomedical application

The preparation, characterization, and preliminary biomedical application of various nitric oxide (NO)-releasing fumed silica particles (0.2-0.3 microm) are reported. The tiny NO-releasing particles are synthesized by first tethering alkylamines onto the surface of the silica using amine-containing silylation reagents. These amine groups are then converted to corresponding N-diazeniumdiolate groups via reaction with NO(g) at high pressure in the presence of methoxide bases (e.g., NaOMe). N-Diazeniumdiolate groups were found to form more readily with secondary amino nitrogens than primary amino nitrogens tethered to the silica. Different alkali metal cations of the methoxide bases, however, have little effect on the degree of N-diazeniumdiolate formation. The N-diazeniumdiolate moieties attached on the silica surface undergo a primarily proton-driven dissociation to NO under physiological conditions, with an "apparent" reaction order somewhat greater than 1 owing to local increases in pH at the surface of the particles as free amine groups are generated. The rates of N-diazeniumdiolate dissociation are further related to the parent amine structures and the pH of the soaking buffer. The N-diazeniumdiolate groups also undergo slow thermal dissociation to NO, with zero-order dissociation observed at both -15 and 23 degrees C. It is further shown that the resulting NO-releasing fumed silica particles can be embedded into polymer films to create coatings that are thromboresistant, via the release of NO at fluxes that mimic healthy endothelial cells (EC). For example a polyurethane coating containing 20 wt % of NO-releasing particles prepared with pendant hexane diamine structure (i.e., Sil-2N[6]-N(2)O(2)Na) is shown to exhibit improved surface thromboresistivity (compared to controls) when used to coat the inner walls of extracorporeal circuits (ECC) employed in a rabbit model for extracorporeal blood circulation.

Pro-inflammatory cytokines after different kinds of cardio-thoracic surgical procedures: is what we see what we know?

OBJECTIVE

Due to the combination of local trauma, extracorporeal circulation (ECC), and pulmonary and myocardial reperfusion, cardiac surgery leads to substantial changes in the immune system and possibly to post-operative complications. Procedures without ECC, however, have failed to demonstrate clear advantages. We hypothesized that ECC is far less important in this context than the reperfusion/reventilation of the lung parenchyma and the surgical trauma. We therefore conducted a prospective observational study to compare immune reactions after cardiac operations with those after thoracic surgery.

METHODS

Serum levels of pro-inflammatory interleukin (IL)-6, IL-8, tumor necrosis factor (TNF)-alpha as well as C-reactive protein (CRP), lipoprotein-binding protein (LBP) and procalcitonin (PCT) were measured pre-operatively (d0), at the end of the operation (dx), 6h after the operation (dx+), on the 1st (d1), 3rd (d3), and 5th (d5) post-operative days in 108 patients (pts) undergoing elective coronary artery bypass grafting (CAB) with ECC (n=42, CPB CAB), off-pump coronary artery bypass surgery (n=24, OP CAB) without ECC or thoracic surgery (n=42, TS).

RESULTS

After cardiac surgery (CS), IL-6 and IL-8 increased and reached a maximum on dx+. IL-6 returned to baseline values at d3, whereas IL-8 remained elevated until d5. No difference was found between OP CAB and CPB CAB patients. In the TS patients, IL-6 increased later (dx+) and absolute levels were lower than in the CS patients. No increase in IL-8 was noted in the TS patients. Due to the high variation in the results obtained in all three groups, there was no significant change in TNF-alpha. A comparison of TS, OP CAB, and CPB CAB revealed that the CS patients had higher levels on d0, dx, d3, and d5. Serum levels of CRP, LBP, and IL-2R increased from dx+ to d5 in all groups and reached maximum values on d3. Whereas we found no difference in CRP and IL-2R between the groups, LBP levels were significantly higher from dx+ to d3 after OP CAB. PCT was elevated from dx+ to d3 in all pts. Similar levels were noted for the TS and OP CAB patients. The CPB CAB patients showed the highest levels.

CONCLUSIONS

Surgical trauma and reperfusion injury appear to represent the predominant factors resulting in immunologic changes after cardiac surgery. Cardiopulmonary bypass (CPB) may be less important for immune response and acute-phase reactions than previously suspected. In addition, our data indicate a relationship between IL-6 synthesis and the degree of surgical trauma. IL-8 appears to be elevated only after cardiac surgery whereas PCT liberation depended on the use of ECC.

Clinical application of bioartificial liver support systems

OBJECTIVE

To review the present status of bioartificial liver (BAL) devices and their obtained clinical results.

BACKGROUND

Acute liver failure (ALF) is a disease with a high mortality. Standard therapy at present is liver transplantation. Liver transplantation is hampered by the increasing shortage of organ donors, resulting in high incidence of patients with ALF dying on the transplantation waiting list. Among a variety of liver assist therapies, BAL therapy is marked as the most promising solution to bridge ALF patients to liver transplantation or to liver regeneration, because several BAL systems showed significant survival improvement in animal ALF studies. Until today, clinical application of 11 different BAL systems has been reported.

METHODS

A literature review was performed using MEDLINE and additional library searches. Only BAL systems that have been used in a clinical trial were included in this review.

RESULTS

Eleven BAL systems found clinical application. Three systems were studied in a controlled trial, showing no significant survival benefits, in part due to the insufficient number of patients included. The other systems were studied in a phase I trial or during treatment of a single patient and all showed to be safe. Most BAL therapies resulted in improvement of clinical and biochemical parameters.

CONCLUSIONS

Bioartificial liver therapy for bridging patients with ALF to liver transplantation or liver regeneration is promising. Its clinical value awaits further improvement of BAL devices, replacement of hepatocytes of animal origin by human hepatocytes, and assessment in controlled clinical trials.

Reduced platelet activation and thrombosis in extracorporeal circuits coated with nitric oxide release polymers

OBJECTIVE

To determine whether the use of nitric oxide (NO)-releasing polymers coated onto the inner surface of extracorporeal circuits can reduce platelet consumption and activation in the absence of systemic heparinization using a rabbit model of venovenous extracorporeal circulation.

DESIGN

Prospective, controlled trial.

SETTING

Research laboratory at an academic medical institution.

SUBJECTS

New Zealand White Rabbits.

INTERVENTIONS

Anesthetized, tracheotomized, and ventilated New Zealand White rabbits were injected with freshly prepared, 111In(oxine)3 labeled single donor platelets through the external jugular vein. After baseline measurements, these animals were placed on venovenous extracorporeal circulation through a 1-m control circuit or NO test circuit for 4 hrs at a blood flow rate of 109-118 mL/min via roller pump. Four groups were studied: systemically heparinized control circuits, systemically heparinized NO test circuits, nonheparinized control circuits, and nonheparinized NO test circuits. Platelet counts, fibrinogen levels, and plasma free indium levels were measured hourly. Circuits were rinsed and retained for gamma counting after the 4-hr run or when the circuit clotted. Four animals, one from each group, did not receive radiolabeled platelets so that the circuits could be preserved for scanning electron microscopic examination after the 4-hr study.

MEASUREMENTS AND MAIN RESULTS

Platelet consumption was significantly reduced in both the heparinized and nonheparinized NO test groups when compared with the controls (p < .0001 and p < .0004, respectively). Platelet adhesion to the extracorporeal circuits was significantly reduced in the nonheparinized test circuits when compared with the controls (p < .05). Scanning electron microscopic examination of the circuits revealed that in the absence of heparin and in the presence of a NO-releasing surface, platelets retained their spherical nonactivated shape.

CONCLUSIONS

The incorporation of NO into the surface of extracorporeal circuits reduces platelet consumption and eliminates the need for systemic heparinization in a rabbit model of extracorporeal circulation.

The first open heart corrections of tetralogy of Fallot. A 26-31 year follow-up of 106 patients

Tetralogy of Fallot became a correctable malformation on August 31, 1954, and from that data through 1960, 106 patients (ages 4 months-45 years) who underwent open repairs at the University of Minnesota and were discharged, have been followed (99% complete) until death or for 26-31 years (mean: 23.7 years, 2424 patient years). The purposes of this study were to determine survival, morbidity, hemodynamics, educational/employment attainments, and relation of these to surgical technics. Operations were done by cross circulation (6 patients) and bubble oxygenator (100 patients). This group had the first uses of patch ventricular septal defect closure, outflow root, infundibuloplasty, atresia correction, ischemic arrests, and pacemakers among other innovations. Twenty-one (of 105 patients) have died during the followup: eight deaths in the first 10 years, 12 between 10 and 20 years, and 1 greater than 20 years. The causes of death were sudden (5), accidental (4), congestive failure (2), reoperation (2), suicide (2), and other (2). Actuarial survival at 30 years was 77%. Late complications were ten reoperations, five arrhythmias, and one endocarditis. Actuarial freedom from reoperations at 30 years was 91%. Cardiac recatheterizations in 62 patients disclosed only 10 with residual shunts. Peak right ventricular systolic pressures were less than 40 mmHg (34 patients), 41-60 mm (2 patients), 61-70 mm (4 patients), greater than 71 mm (4 patients). Thirty-four patients (32%) completed college, ten of these completed graduate school (5 masters degrees, 2 M.D.'s, 2 Ph.D.'s, 1 lawyer). Fifteen others attended college, and nine received technical school diplomas. Forty patients (18 men, 22 women) had progeny, with 82 (93%) live births and six major cardiac defects (7.3%). In summary, complete repair gave excellent late results in this group cared for very early in the open heart era. Survivors led productive lives without restrictions in education and employment. Many of the deaths/complications that occurred are now easily preventable, which augurs extremely well for this generation.

Prospective randomized study comparing coronary artery bypass grafting with the new mini-extracorporeal circulation Jostra System or with a standard cardiopulmonary bypass

BACKGROUND

To assess the potential benefits of a new concept of cardiopulmonary bypass (CPB), the mini-extracorporeal circulation (MECC) Jostra System, we conducted a prospective randomized study among patients who underwent coronary artery bypass grafting (CABG) with a MECC Jostra System or with a standard CPB.

METHODS

In a prospective randomized study, 400 patients underwent elective CABG using a standard CPB (200 patients) or a Jostra MECC System (200 patients). The patients were randomly assigned to have preoperative data similar for both groups.

RESULTS

The operative mortality rate (< 30 days) was 1.5% for the MECC group and 2.5% for the CPB group (P = NS). Low-cardiac-output syndrome occurred in 0.66% and 4% for the CPB group (P < .001.). The inflammatory response was significantly reduced with the MECC. Likewise, C-reactive protein release was significantly higher in group B at 24 hours (69.6 +/- 38.5 vs 40.8 +/- 21.8 mg/L for the group A, P < .01) and at 48 hours (116.7 +/- 47.0 vs 65.4 +/- 39.5 mg/L, P < .05) postoperatively. In the CPB group, there was a significantly higher decrease of hematocrit and hemoglobin rate. So, the intraoperative transfusion rate amounted to 6% for the MECC group and 12.8% for the CPB group (P < .001). Patients in the CPB group had significantly higher levels of postoperative blood creatinine and urea.

CONCLUSION

The MECC system is a new concept of CPB that seems to be reliable and safe. To perform CABG, the MECC provides an excellent surgical exposure like a standard CPB and a better biologic profile like CABG without CPB.

The feasibility and safety of extracorporeal carbon dioxide removal to avoid intubation in patients with COPD unresponsive to noninvasive ventilation for acute hypercapnic respiratory failure (ECLAIR study): multicentre case-control study

INTRODUCTION

The aim of the study was to evaluate the feasibility and safety of avoiding invasive mechanical ventilation (IMV) by using extracorporeal CO2 removal (ECCO2R) in patients with acute exacerbation of chronic obstructive pulmonary disease (COPD) and acute hypercapnic respiratory failure refractory to noninvasive ventilation (NIV).

METHODS

Case-control study. Patients with acute hypercapnic respiratory failure refractory to NIV being treated with a pump-driven veno-venous ECCO2R system (iLA-Activve(®); Novalung, Heilbronn, Germany) were prospectively observed in five European intensive care units (ICU). Inclusion criteria were respiratory acidosis (pH ≤ 7.35, PaCO2 > 45 mmHg) with predefined criteria for endotracheal intubation (ClinicalTrials.gov NCT01784367). The historical controls were patients with acute hypercapnic respiratory failure refractory to NIV who were treated with IMV. The matching criteria were main diagnosis, age, SAPS-II score and pH.

RESULTS

Twenty-five cases (48.0 % male, mean age 67.3 years) were matched with 25 controls. Intubation was avoided in 14 patients (56.0 %) in the ECCO2R group with a mean extracorporeal blood flow of 1.3 L/min. Seven patients were intubated because of progressive hypoxaemia and four owing to ventilatory failure despite ECCO2R and NIV. Relevant ECCO2R-associated adverse events were observed in 11 patients (44.0 %), of whom 9 (36.0 %) suffered major bleeding complications. The mean time on IMV, ICU stay and hospital stay in the case and control groups were 8.3 vs. 13.7, 28.9 vs. 24.0 and 36.9 vs. 37.0 days, respectively, and the 90-day mortality rates were 28.0 vs. 28.0 %.

CONCLUSIONS

The use of veno-venous ECCO2R to avoid invasive mechanical ventilation was successful in just over half of the cases. However, relevant ECCO2R-associated complications occurred in over one-third of cases. Despite the shorter period of IMV in the ECCO2R group there were no significant differences in length of stay or in 28- and 90-day mortality rates between the two groups. Larger, randomised studies are warranted for further assessment of the effectiveness of ECCO2R.

To pulse or not to pulse

Pulsatile and nonpulsatile blood flow have been intensely studied for cardiopulmonary bypass (CPB), isolated organ perfusion, and myocardial preservation. Although early studies differed, later ones have shown the benefits of pulsatile flow. Kidney function, lymph flow, and oxygen consumption are increased during pulsatile perfusion. Also, nonpulsatile CPB increases total peripheral resistance and mean arterial pressure, which are related to time of perfusion. Theories to account for the superiority of pulsatile flow include: (1) "vascular shocks" causing physical displacement of tissues, which changes the boundary layer of interstitial fluid around cell membranes and enhances diffusion ;(2) increased lymph movement during pulsatile flow; and (3) pulsatile energy ensuring the patency of the vascular beds and preventing shunting. New methods to create pulsatile flow and their adaptation to the standard roller pump are discussed.

Leukocytapheresis in ulcerative colitis: results of a multicenter double-blind prospective case-control study with sham apheresis as placebo treatment

OBJECTIVE

Leukocytapheresis (LCAP) is a method of therapeutic apheresis that removes peripheral leukocytes. Previous studies showed that in patients with ulcerative colitis (UC), LCAP was more effective than high-dose steroid therapy, and it had few adverse effects. We investigated LCAP in a multicenter study using active and sham devices in a double-blind study in order to elucidate the placebo effect of extracorporeal treatment including anticoagulant medication.

METHODS

Twenty-five patients with active UC of severe or moderately severe grade were enrolled and assigned to the active group or the sham group. Six patients were excluded from the study and 19 (10 in the active group and nine in the sham group) were evaluated. LCAP (treatment using an active device or a sham device) was performed once a week for 5 wk, followed by two additional sessions during the next 4 wk at 2-wk intervals. Steroids and other medications were continued at the same dosage for 4 wk, which included a 2-wk pre-observation period and the first 2 wk after the start of the LCAP treatment. New medications or increase in the dosage of previous medication were prohibited until evaluation was conducted.

RESULTS

The clinical activity index (CAI) value of UC, indicated that the active group showed a significantly greater improvement (80%, 8/10) than the sham group (33%, 3/9; p<0.05). Adverse effects were observed in five patients (one in the active group and four in the sham group). None of these effects was severe and none of the sessions was terminated as a consequence of the adverse effects.

CONCLUSION

The results confirmed that LCAP is a safe and effective therapeutic option for patients with active UC.

Extracorporeal life support in critically ill adults

Extracorporeal life support (ECLS) has become increasingly popular as a salvage strategy for critically ill adults. Major advances in technology and the severe acute respiratory distress syndrome that characterized the 2009 influenza A(H1N1) pandemic have stimulated renewed interest in the use of venovenous extracorporeal membrane oxygenation (ECMO) and extracorporeal carbon dioxide removal to support the respiratory system. Theoretical advantages of ECLS for respiratory failure include the ability to rest the lungs by avoiding injurious mechanical ventilator settings and the potential to facilitate early mobilization, which may be advantageous for bridging to recovery or to lung transplantation. The use of venoarterial ECMO has been expanded and applied to critically ill adults with hemodynamic compromise from a variety of etiologies, beyond postcardiotomy failure. Although technology and general care of the ECLS patient have evolved, ECLS is not without potentially serious complications and remains unproven as a treatment modality. The therapy is now being tested in clinical trials, although numerous questions remain about the application of ECLS and its impact on outcomes in critically ill adults.

Left ventricular subendocardial necrosis

The hearts of as many as 90% of patients who die after open-heart operations have left ventricular subendocardial necrosis. This form of myocardial infarction depresses myocardial performance postoperatively and may result in late myocardial fibrosis. It occurs without anatomical obstruction of the coronary arteries and is caused by a discrepancy between subendocardial oxygen supply and demand during the perioperative period. This review of subendocardial necrosis summarizes the author's current understanding of: (1) why the subendocardium is especially vulnerable to this injury; (2) how to predict which patients are most susceptible to it; (3) how interventions before, during, and after extracorporeal circulation can either contribute to it, minimize its severity, or prevent it; and (4) where future study of this problem should be directed.

Comparison of the use of standard heparin and prostacyclin anticoagulation in spontaneous and pump-driven extracorporeal circuits in patients with combined acute renal and hepatic failure

Although prostacyclin has been reported to be an effective extracorporeal anticoagulant for intermittent haemofiltration and dialysis treatments, it has been suggested that it is inferior to heparin in preventing clotting in spontaneously driven continuous haemofiltration and/or dialysis circuits. We studied the effectiveness of both heparin and prostacyclin as anticoagulants in a variety of extracorporeal circuits in 17 patients with combined acute hepatic and renal failure who were at risk of haemorrhage. Although there were no differences in the pump-assisted extracorporeal circuits, prostacyclin was found superior to heparin during spontaneously driven continuous arteriovenous haemofiltration and/or dialysis. During some 2,600 h of prostacyclin therapy, there were only 3 episodes of haemorrhage that required blood transfusion compared to 8 major haemorrhages and 2 deaths from intracerebral haemorrhage during 600 h of anticoagulation with heparin. The median filter life was greater with prostacyclin, 60 h (42-72), compared to heparin, 8 h (4-16), p < 0.01. This study suggests that prostacyclin is superior to heparin in maintaining the integrity of a spontaneous arteriovenous extracorporeal circuit in patients at risk of major haemorrhage.

Significance of serum S100 release after coronary artery bypass grafting

BACKGROUND

S100 protein has been suggested to be a serum marker for cerebral complications after cardiac operation and extracorporeal circulation. The aim of this study was to characterize the S100 release pattern after extracorporeal circulation in 515 consecutive patients undergoing coronary artery bypass grafting.

METHODS

Clinical variables and outcome were prospectively registered. The cerebral outcome was determined by clinical examination. S100 was measured at the end of extracorporeal circulation, and after 5, 15, and 48 hours.

RESULTS

After operation, 13 patients had stroke, 12 had delayed awakening, and 17 had encephalopathy. Early S100 release, immediately after extracorporeal circulation, was associated with age and perfusion time, but not with cerebral outcome. However, S100 release after 5 to 48 hours was associated with cerebral complications and risk factors for such outcome. Patients with stroke had higher S100 levels after 15 to 48 hours. A subset of patients with renal failure had overall higher S100 levels at 5 hours.

CONCLUSIONS

Early and late S100 release indicate different mechanisms for release and emphasizes the potential power of this new biochemical marker for cerebral damage.

Venovenous Extracorporeal Life Support After Pulmonary Endarterectomy: Indications, Techniques, and Outcomes

BACKGROUND

Pulmonary endarterectomy is the accepted therapy for thromboembolic pulmonary hypertension. A recognized complication of this surgery is the postoperative development of reperfusion edema, a potentially fatal cause of respiratory failure. Because reperfusion edema can be a reversible process, temporizing support measures may be life saving.

METHODS

We retrospectively reviewed our experience with venovenous extracorporeal life support (V-V ECLS) from July 1990 to February 2006, in 20 adult patients (mean age 50.5 +/- 14.5 years) presenting with potentially reversible respiratory failure after pulmonary endarterectomy. This subset of patients comprised 1.12% of our total pulmonary endarterectomy experience during that time (1,790 cases).

RESULTS

Overall in-hospital survival was 30.0% for patients requiring ECLS support after pulmonary endarterectomy versus 94.2% for patients who underwent pulmonary endarterectomy alone during the same timeframe. V-V ECLS was instituted at a mean of 86.8 hours after surgery. The mean duration of V-V ECLS was 123.4 +/- 71.3 hours. The most common cause of death in ECLS patients after pulmonary endarterectomy was pulmonary hemorrhage. Survival was greater in patients cannulated within 120 hours of surgery (46.2% survival; 6 of 13 patients) compared with those cannulated after 120 hours (0 of 7 patients). Multiple logistic regression identified long duration of mechanical ventilation pre-ECLS and severity of preoperative pulmonary hypertension together as predictors of mortality.

CONCLUSIONS

A small subset of patients undergoing pulmonary endarterectomy develop temporary life-threatening respiratory failure secondary to severe reperfusion edema. In those patients with satisfactory hemodynamic outcome, V-V ECLS is a therapeutic option when all other conventional strategies have been exhausted.

Retrograde cerebral perfusion for aortic arch surgery: analysis of risk factors

BACKGROUND

Retrograde cerebral perfusion (RCP) has been widely adopted during aortic arch surgery under hypothermic circulatory arrest (HCA). However, the risks in terms of mortality and morbidity in aortic arch surgery using HCA with RCP have not yet been confirmed.

METHODS

The present study is a retrospective review of 249 patients who underwent aortic arch surgery at three Japanese cardiovascular centers where RCP is a routine adjunct. The median age was 65 years, and 38 patients were more than 75 years old. The pathology in the aortic arch was atherosclerotic aneurysm in 133 patients and dissection in 116. Seventy patients had surgery on an emergency basis. Surgery was performed through a median sternotomy in 182 patients and through a left thoracotomy in 67. Using HCA with RCP, graft replacement of the total aortic arch was performed in 109, the distal arch in 63, and the ascending aorta and hemi-arch in 66; 11 patients had patch repair.

RESULTS

The overall hospital mortality was 25/249 (10%), and 12/70 (17%) in emergent surgery. Stroke developed in 11 patients (4%). The median duration of RCP was 46 minutes (range, 5 to 95). Univariate analysis of risk factors revealed that an age of 75 years or more (p < 0.001), and urgency of surgery (p = 0.02) affected hospital mortality. Multivariate logistic analysis revealed that pump time (p = 0.0001), age (p = 0.0001) and RCP time (p = 0.05) are the most significant risk factors for mortality. The risk factors for mortality and neurological morbidity combined are pump time (p = 0.0001), age (p = 0.0002), and urgency of surgery (p = 0.07); RCP time is marginally significant (p = 0.15).

CONCLUSIONS

The dominant risk factors for mortality and morbidity are pump time, urgency of the surgery, and age. RCP is a simple and useful adjunct for aortic arch surgery with up to 80 minutes of HCA, although prolonged RCP is a risk factor for mortality and morbidity.

Improvement of multiple organ functions in hepatorenal syndrome during albumin dialysis with the molecular adsorbent recirculating system

Recently, significant improvement of renal function and prolongation of survival were reported in hepatorenal syndrome (HRS) patients treated with the Molecular Adsorbent Recirculating System (MARS). As no impact on extrarenal organ function was documented, this trial looked into multiple organ function changes during MARS in HRS patients. Eight HRS patients (4 male, mean age 42.1 years, range 30-58, all United Network for Organ Sharing [UNOS] status 2A) were treated intermittendly 4-14 times (total 47, mean 5.9 +/- 3.4) between 4 and 8 h/single treatment. The following changes were observed pre- and posttreatment: bilirubin 466 +/- 146 to 284 +/- 134 micromol/L, creatinine 380 +/- 182 to 163 +/- 119 micromol/L, urea 26.4 +/- 10.3 to 12.9 +/- 4.9 mmol/L, plasma sodium 127.5 +/- 7.7 to 137.5 +/- 4.8 mmol/L (all p < 0.01). Mean arterial pressure (MAP) increased from 71.9 +/- 12.8 to 95.6 +/- 7.8 Torr (p < 0.001). Oliguria or anuria, present in all patients, was successfully reverted. Ascites, present in all patients, was not detectable after the treatment period. The hepatic encephalopathy grade decreased from 2.8 +/- 0.8 to 0.8 +/- 0.7 (p < 0.0001). Child-Index decreased from 13.25 +/- 1.3 to 9.4 +/- 1.8 (p < 0.001). The hospital survival rate was 62%. One man underwent successful liver transplantation 18 months after the treatment. We conclude that MARS can improve multiple organ functions in patients with HRS.