Introduction: Long term graft patency is the major factor for survival in patients after coronary artery bypass grafting (CABG). When using radial arteries as a graft the occurrence of spasm (strings) may be of concern. We determined the presence of radial artery string signs immediately after completion of the grafts and, if diagnosed, investigated the effects of intra-graft vasodilator therapy.

Background. The effect of reduced cardiopulmonary bypass (CPB) prime volume by retrograde autologous priming (RAP) was studied.Methods. Twenty patients undergoing elective coronary artery bypass grafting were randomized to either standard prime (SP) volume (1,602 +/- 202 mL, crystalloid prime, n = 10) or RAP (395 +/- 150 mL). RAP was performed by draining crystalloid prime from the arterial and venous lines into a recirculation bag before CPB. Cardiac index, pulmonary vascular resistance index, systemic vascular resistance index, alveolar-arterial oxygen tension difference, pulmonary shunt fraction, extravascular lung water (EVLW), plasma colloid osmotic pressure (COP), crystalloid fluid balance, body weight, and clinical parameters were evaluated perioperatively.Results. Demographic data and operative parameters were equal for patients in both groups. During CPB, COP was reduced by 55% in the SP group (9.8 +/- 2.0 vs 21.4 +/- 2.1 mm Hg) and by 41% in the RAP group (12.4 +/- 1.1 vs 20.9 +/- 1.8 mm Hg) (p = 0.008, SP vs RAP group). Compared with preoperatively, EVLW was unchanged in the RAP group 2 hours post-CPB, but it was elevated by 21% in the SP group (p = 0.002, SP vs RAP group). End-CPB crystalloid fluid balance was significantly reduced in the RAP group (1,857 +/- 521 vs 2,831 +/- 637 mL). Postoperative (day 2) weight gain in the SP group (1.5 +/- 1.2 kg, p = 0.021) was absent in the RAP group (0.1 +/- 0.9, NS). Postoperative time to full mobilization was shorter in the RAP group. Postpump cardio-respiratory function did not differ among groups.Conclusions. This small-scale pilot study indicates that by reducing crystalloid fluid administration and fall of COP during CPB, RAP reduces postpump EVLW accumulation and weight gain in uncomplicated coronary artery bypass graft patients with no associated effects on cardio-respiratory function. (C) 2003 by The Society of Thoracic Surgeons.

Untersuchungsgegenstand war der Einfluss der Hämofiltration auf die Funktion von Herz und Lunge, auf den Entzündungsprozess sowie auf das Ausmaß der Ödembildung nach extrakorporaler Zirkulation (EKZ). Um den Effekt der Hämofiltration unabhängig von einer Hämokonzentration zu erfassen, wurde eine isovolumische Hämofiltration durchgeführt.    Dazu wurden 26 Schweine einer 2 stündigen EKZ einschließlich 90min kardioplegischem Herzstillstand und anschließender 30min Reperfusion unterzogen. Bei 13 Tieren wurde eine Hämofiltration durchgeführt, und zwar für 30min während der Reperfusionszeit und für weitere 30min nach Ende der EKZ. Das abfiltrierte Volumen wurde durch Ringerlaktat ersetzt. Die Nachbeobachtungszeit nach Ende der EKZ betrug 5 Std. Ergebnisse Nach Ende der EKZ zeigte sich in beiden Gruppen eine gleichermaßen eingeschränkte linksventrikuläre Funktion, die durch eine erhöhte Herzfrequenz sowie durch erniedrigten Aortendruck, Herzzeitvolumen und dp/dtmax zum Ausdruck kommt. Auch die Lungenfunktion war signifikant eingeschränkt. So blieb zwar das pulmonale Shuntvolumen unverändert, die pulmonale Compliance war jedoch um 10–15% veringert bei einem pulmonalen Gefäßwiderstand, der doppelt so hoch war wie vor Beginn der EKZ. Die Alveolo-arterielle Sauerstoffpartialdruck Differenz blieb bei den Kontrolltieren unverändert, während sie nach Hämofiltration bis zu 34% erhöht war. Post mortem Messungen des Wassergehaltes vom Myokard sowie von der rechten Lunge wiesen in beiden Gruppen ähnliche Werte auf, während die linke Lunge in der HF-Gruppe einen 10% höheren Wassergehalt zeigte als in der Kontrollgruppe. Nach Ende der EKZ kam es in der Kontrollgruppe zu einem signifikanten Anstieg der TNF-α und IL-10 Plasmaspiegel, der nach Hämofiltration nicht nachweisbar war. Histologische Untersuchungen des Myokards nach Versuchsende ergaben keine Unterschiede zwischen den beiden Gruppen hinsichtlich der Qualität und der Quantität der leukozytären Infiltration in das Gewebe. Schlussfolgerung Die vorliegende Studie konnte den negativen Einfluss der EKZ auf die kardiopulmonale Funktion am Schweinemodell bestätigen. Die intraoperative Hämofiltration ohne Hämokonzentration konnte in der vorliegenden Versuchsanordnung die kardio-pulmonale Funktion, trotz dokumentierter Reduktion inflammatorischer Mediatoren, nicht positiv beeinflussen. Dies steht im Widerspruch zu den Ergebnissen aus der pädiatrischen Kardiochirurgie. Am ehesten sind die Unterschiede darauf zurückzuführen, dass in der pädiatrischen Kardiochirurgie kolloidale statt, wie in der vorliegenden Studie, nicht-kolloidale Flüssigkeiten als Volumenersatz Verwendung finden. Der wesentliche Faktor, der bei intraoperativer Hämofiltration die kardio-pulmonale Funktion nach EKZ verbessern kann, scheint also die Hämokonzentration und nicht primär die Elimination inflammatorischer Mediatoren zu sein.

In einer prospektiven, randomisierten Studie sollte der Effekt eines reduzierten Füllvolumens (Priming) für die extrakorporale Zirkulation (EKZ) durch retrogrades autologes Priming (RAP) auf das Ausmaß der postoperativen interstitiellen Ödembildung untersucht werden. 20 Patienten, die sich einer elektiven koronaren Bypassoperation unterzogen, wurden entweder einer Gruppe mit Standardpriming (SP, 1602±202ml kristalloide Vorfüllung, n=10) oder einer RAP-Gruppe (395±150ml) zugeordnet. RAP wurde vor Beginn der EKZ durch langsames Ersetzen der kristalloiden Vorfüllung der arteriellen und venösen Linien mit Patientenblut durchgeführt. Perioperativ wurden die kardiale und pulmonale Funktion, das extravasale Lungenwasser (EVLW), der plasma kolloidosmotische Druck (KOD), die kristalloide Flüssigkeitsbilanz sowie das Körpergewicht der Patienten aufgezeichnet. Ergebnisse Hinsichtlich demographischer und operativer Parameter waren die Patienten gleichermaßen auf die Gruppen verteilt. Durch RAP konnte der Abfall des KOD während der EKZ von 54% in der SP-Gruppe auf 41% signifikant reduziert werden. 2 Std. nach Ende der EKZ war das EVLW im Vergleich zu präoperativ in der Standard-Gruppe um 21% signifikant erhöht, während es in der RAP-Gruppe im gleichen Zeitraum unverändert blieb. Die Bilanz der kristalloiden Flüssigkeiten von OP-Beginn bis EKZ-Ende waren in der RAP-Gruppe signifikant niedriger als in der SP-Gruppe (1857±521 gegenüber 28310±637ml). Zwei Tage postoperativ ergab sich für die Standard-Gruppe eine Zunahme des Körpergewichts um 1,5±1,2kg (p<0,05), während das Gewicht in der RAP-Gruppe unverändert blieb (0,1±0,9kg). Auch die Dauer des stationären Aufenthaltes war in der RAP-Gruppe signifikant kürzer als in der Standard-Gruppe. Schlussfolgerungen Durch RAP kann die ausgeprägte Hämodilution und der Abfall des KOD mit Beginn der EKZ vermindert werden. Dadurch kann das Ausmaß interstitieller Ödeme am Beispiel des EVLWs sowie die perioperative Gewichtszunahme signifikant gesenkt werden, was schließlich zu einem verkürzten Klinikaufenthalt der Patienten führte. Besonders günstig könnte sich RAP auf den postoperativen Verlauf bei Patienten mit eingeschränkten Organfunktionen auswirken.

OBJECTIVE:Operations coupled with cardiopulmonary bypass may provoke a systemic inflammatory response, and it has been suggested that this responses causes capillary leakage of proteins, edema formation, and even organ failure. However, capillary leak syndrome is mainly a clinical diagnosis and has not been verified as yet by actual demonstration of protein leakage from the circulation. We have therefore measured the disappearance of labeled plasma protein before and after cardiopulmonary bypass.METHODS:Sixteen patients scheduled for elective coronary artery bypass grafting were enrolled in a prospective controlled study. The cardiopulmonary bypass circuit was primed with crystalloids only. Tumor necrosis factor alpha, interleukin 6, interleukin 8, anaphylatoxin C3a, and terminal complement complex C5b9 levels were determined before, during, and 3 hours after cardiopulmonary bypass. The transvascular escape rate of plasma protein from the intravascular compartment was assessed by measuring the disappearance of intravenously injected Evans blue dye before and during the third hour after cardiopulmonary bypass.RESULTS:A significant inflammatory response could be demonstrated by means of the 5 measured mediators after bypass. The maximal increase, as compared with the baseline value, was found for interleukin 6 (36-fold). The transvascular escape rate of Evans blue dye was similar before and after bypass (7.6 +/- 0.6%/h vs 7.3 +/- 0.6%/h).CONCLUSIONS:The above data confirm the systemic inflammatory response induced by cardiopulmonary bypass. Contrary to expectations, the transvascular escape rate of Evans blue dye did not change when comparing values before and after bypass. The data do not support the concept of increased protein leakage in the exchange vessels after bypass. We were unable to demonstrate a capillary leak syndrome.

Objective: Different types of colloidal priming for cardiopulmonary bypass (CPB) have been used to reduce fluid load and to avoid the fall of plasma colloid osmotic pressure, (COP) that leads to edema formation and consequently can cause organ dysfunction. The discussion about the optimal priming composition, however, is still controversial We investigated the effect of a hyperoncotic CPB-prime with hydroxyethyl starch (HES) 10% (200;0.5) on extravascular lung water (EVLW) and post-pump cardiac and pulmonary functions. Methods: In 20 randomized patients undergoing elective coronary artery bypass graft surgery (CABG), a colloid prime (COP: 48 mmHg HES-group, n = 10) and a crystalloid prime (Ringer's lactate, crystalloid group, n = 10) of equal volume were compared with respect to the effects on cardiopulmonary function. Cardiac index (CI), mean arterial pressure (MAP), pulmonary capillary wedge pressure (PCWP), systemic vascular resistance index (SVRI), pulmonary artery pressure (PAP), pulmonary vascular resistance index (PVRI), alveolo-arterial oxygen difference (AaDO(2)), pulmonary shunt fraction (Q(s)/Q(T)), EVLW (double-indicator dilution technique with ice-cold indocyanine green), COP, fluid balance and body weight were evaluated peri-operatively. Results: Pre-operative demographic and clinical data, CPB-time,. crossclamp time and the number of anastomoses were comparable for both groups. During CPB, COP was reduced by 20% in the HES-group (18.9 +/- 3.7 vs. 23.7 +/- 2.2 mmHg, P < 0.05) while it was reduced by more than 50% of the pre-CPB value (9.8 +/- 2.0 vs. 21.4 +/- 2.1 mmHg, P < 0.05) in the crystalloid group (P < 0.05 HES- vs. crystalloid group). Post-CPB EVLW was unchanged in the RES-group but it was elevated by 22% in the crystalloid group (P < 0.05 HES- vs. crystalloid group), CI was higher in the HES-group (3.4 +/- 0.3 vs. 2.7 +/- 0.5 l/min, P < 0.05). Fluid balance was less in the HES-group (813 +/- 619 vs. 2143 +/- 538, P < 0.05). Post-operative weight gain could be prevented in the HES-group but not in the crystalloid group (1.5 +/- 1.2 vs. -0.3 +/- 1.5, P < 0.05). No significant differences were seen for MAP, PAP, PCWP, SVRI, PVRI, AaDO(2) and (Q(s)/Q(T)) between the two groups at any time. Conclusions: Hyperoncotic CPB-prime using RES 10% improves CI and prevents EVLW accumulation in the early post-pump period, while pulmonary function is unchanged. This effect can be of benefit especially in patients with congestive heart failure. (C) 2001 Elsevier Science B.V. All rights reserved.

OBJECTIVE To determine if prophylactic administration of C1-esterase-inhibitor would have a beneficial effect on postoperative weight gain and the inflammatory response in neonates undergoing cardiac surgery with cardiopulmonary bypass (CPB). DESIGN Randomized, double-blinded study. SETTING University-affiliated heart center. PARTICIPANTS Twenty-four neonates with transposition of the great arteries. INTERVENTIONS In group inhibitor (INH) patients (n = 12), 100 IU/kg of C1-esterase-inhibitor (Berinert) was given 30 minutes before CPB. In group placebo (P) patients (n = 12), placebo was administered instead. Interleukin (IL)-6, C3a anaphylatoxin, C1 activity, prekallikrein, Hageman factor, D-dimers, and clinical parameters were measured 6 times perioperatively. MEASUREMENTS AND MAIN RESULTS All 24 patients had an uneventful clinical course. Mean arterial pressure and pulmonary oxygenation after CPB were superior in group INH patients. The weight gain on postoperative days 1 to 4 was significantly less in group INH patients compared with group P (55 +/- 59 g vs. 340 +/- 121 g, day 1). The concentration of IL-6 (76 +/- 17 pg/mL vs. 262 +/- 95 pg/mL during CPB) was significantly lower in group INH patients compared with group P patients. In contrast, no influence on C3a anaphylatoxin and coagulation factors was found. CONCLUSION Prophylactic application of C1-esterase-inhibitor in neonates undergoing arterial switch operations produces less inflammatory response compared with placebo. This difference may have contributed to improved clinical parameters, including less weight gain postoperatively.

BACKGROUND:The hypothesis that an inflammatory process during and after cardiopulmonary bypass (CPB) impairs hemodynamics and causes increased capillary protein leakage and that this is possibly ameliorated by hemofiltration (HF) was tested.METHOD:26 anesthetized pigs were subjected to 120 min CPB (90 min cardioplegia followed by 30 min reperfusion, combined with conventional and modified HF in 13 animals). Hemodynamics, leukocytes, cytokines (IL-1ra, IL-8, IL-10, TNF-alpha), LNPI, plasma protein, and the half-life of i.v. injected Evans Blue (t/2) were assessed before and after CPB.RESULTS:CPB was followed by depression of left ventricular function and activation of inflammatory mediators. Although a slight elimination of some inflammatory mediators occurred, HF did neither improve cardiac function nor reduce the inflammatory process. Plasma protein was lost during CPB and hemofiltration by protein trapping to the surfaces of the CPB system, by filtration across the hemofilter, and by increased microvascular filtration (solvent drag). The latter was probably due to an increased filtration pressure in consequence of the reduction of plasma colloid osmotic pressure by the crystalloid primed CPB. t/2 did not indicate an increased microvascular protein leakage after CPB.CONCLUSION:Hemofiltration is ineffective in improving cardiac function or reducing the inflammatory response of CPB in the pig model.

Objective: To evaluate whether combined zero-balanced and modified ultrafiltration affects the systemic inflammatory response in coronary artery bypass graft (CABG) patients.Design: Randomized and controlled.Setting: University-affiliate heart center.Participants: Forty-three patients scheduled for elective CABG.Interventions: In the ultrafiltration group (UF group; n = 21), zero-balanced ultrafiltration was performed during rewarming and modified ultrafiltration immediately after the end of cardiopulmonary bypass (CPB). A control group of patients (n = 22) was treated identically to the treatment group except no ultrafiltration process was performed.Measurements and Main Results: Immediately after CPB (ie, after zero-balanced ultrafiltration), and again after the modified ultrafiltration, the concentrations of interleukin-6 and interleukin-8 were significantly less (p < 0.05) in the UF group compared with the control group. Both proinflammatory cytokine levels peaked at 2 and 4 hours after CPB, at which time no difference between the two groups could be observed. The levels of measured anti-inflammatory mediators (interleukin-10 and interleukin-1 receptor antagonist) did not show any difference between the two groups. Intrapulmonary shunt fraction decreased in the course of the modified ultrafiltration from 31% +/- 1.2% to 25% +/- 1.3% (p < 0.01), whereas mean arterial pressure increased (69 +/- 1.8 to 80 +/- 2.8 mmHg; p < 0.01); neither parameter changed in the control group. Time to extubation was shorter in the UF group (6.1 +/- 0.5 v 8.6 +/- 0.7 hours; p < 0.05).Conclusion: It was concluded that the use of ultrafiltration diminished inflammatory response in a very limited time period immediately after CPB and, probably as a consequence, slightly improved clinical parameters. Copyright (C) 1999 by W.B. Saunders Company.

O Ob bj je ec ct ti iv ve es s: : Acute renal failure (ARF) is a common complication following open heart surgery especially in infants.Effects of blood viscosity on renal function are well known, but have not been investigated in cardiopulmonary bypass (CPS) as yet.M Ma at te er ri ia al l a an nd d m me et th ho od ds s: : We investigated blood viscosity and different markers of glomerular and tubular renal function in a group of 37 infants below 18 month of age, receiving CPS surgery for different diagnoses.In an experimental setting, we investigated 28 isolated pig-kidneys with different hematocrits in an autologous blood perfused model.R Re es su ul lt ts s: : In infants, creatinine clearance decreased and urinary excretion of albumin and β-NAG increased during the aortic cross clamp time (AT) and during the first hours following operation, indicating moderate glomerular and tubular damage.During AT, blood was hemodiluted to a hemoglobin of 8.4 ± 0.4 g/dl.Thus, blood viscosity during AT and hypothermia was slightly below pre-CPB values.Lower blood viscosity was related to less renal damage (P < 0.01).In isolated pig-kidneys, group I (n = 14) was perfused with a hemoglobin of 10.2 ± 0.3 g/dl and group II (n = 14) was hemodiluted to 6.5 ± 0.9 g/dl.Group II kidneys showed lower vascular resistance, elevated creatinine clearance, elevated oxygen consumption and elevated sodium reabsorption (P < 0.05).C Co on nc cl lu us si io on ns s: : Reducing blood viscosity below physiological values improves tubular as well as glomerular function under CPB conditions.Thus we hold hemodilution to be an appropriate method for optimizing CPB procedures.

OBJECTIVE:Most mammalian cardiac muscles show a positive force-frequency relation, which is turned into a negative relation in failing hearts. Stunned myocardium shows similar defects as failing myocardium, it has a functional reserve recruitable by positive inotropic interventions, and possibly shows a disturbed response to increased heart rate. The present experiments compare in vivo the response of stunned and intact myocardium to atrial pacing before and during inotropic stimulation by milrinone.METHODS:In anaesthetised (piritramide) open chest pigs, heart rate, left ventricular and aortic pressure, left descending (LAD) and circumflex (LCX) coronary artery and aortic blood flow, myocardial systolic shortening in the LAD and LCX area were monitored, and myocardial power was calculated. The LAD region was subjected to ischaemia and reperfused. Heart rate was raised by right atrial pacing after 90 min reperfusion before and during i.v. milrinone (105 microg/kg bolus + 8 microg/kg per min infusion). The ischaemic/reperfused area was sliced post mortem and stained by triphenyl tetrazolium chloride to exclude myocardial infarction. Data from ten experiments are presented.RESULTS:After 90 min LAD reperfusion, LAD blood flow and power were 110 and 36% of preischaemic control, respectively, indicating myocardial stunning. The power of the intact area was not changed (102% of control). Pacing from 87 to 164 per min increased the power of the intact area (+96%), the power of the stunned myocardium decreased (-64%). Milrinone increased the power of the stunned region to 72% of the pre-stunning level and the power of the intact area by +51%. Pacing from 111 to 164 per min during milrinone increased the power of the intact myocardium to the same level as before milrinone, the power of the stunned region did not change.CONCLUSIONS:Stunned myocardium responds pathologically to atrial pacing with a negative staircase in contrast to the positive staircase of intact myocardium. Inotropic stimulation by the phosphodiesterase inhibitor milrinone recruited the functional reserve of stunned myocardium. Milrinone did not restore a positive staircase in stunned myocardium, but power was maintained during atrial pacing. The pathological staircase of stunned myocardium may arise from an impaired availability of cyclic AMP, but the data do not exclude defects in calcium handling, a dysfunction of the sarcoplasmic reticulum, or an impaired Ca-sensitivity of the myofilaments.