Thomas Hospital Solution Research Articles

Safety of Custodiol cardioplegia: a cohort study in patients undergoing cardiac surgery with elongated aortic cross-clamp time.

The increasing complexity of patients undergoing cardiac surgery requires extended myocardial ischaemic periods. Cardiac surgeons demand a cardioplegic solution with prolonged myocardial protection. Therefore, we introduced Custodiol in our centre in 2011. The aim of this study was to investigate the safety and efficacy of Custodiol compared with the standard method of cardioplegia. Between 2011 and 2016, 188 adult patients who underwent mitral valve surgery combined with coronary artery bypass grafting were included in this retrospective study. In 113 patients, Custodiol cardioplegia was used to achieve cardiac arrest, while St. Thomas Hospital solution was used in 75 patients. The primary endpoint of the study was the degree myocardial damage which was estimated by the measurement of creatine kinase-myocardial band on the first postoperative day. A linear regression analysis was performed to compare the aortic cross-clamp time with the postoperative myocardial damage in both groups. The extracorporeal circulation time and aortic cross-clamp were significantly longer in the Custodiol group than in the St. Thomas group: 125.6 ± 32.5 minutes versus 93.1 ± 27.7 minutes (p < 0.001), respectively. However, there was no significant difference between the two groups regarding the postoperative levels of creatine kinase-myocardial band (96 (70-140) U/L vs. 86 (69-120) U/L, respectively; p = 0.321). There was no significant differences between the two groups regarding the 30-day mortality (6.1% vs. 5.5%, respectively; p = 1.000) or 120-day mortality (9.6% vs. 11.0%, respectively; p = 0.806). Our findings demonstrate that Custodiol is a safe method of myocardial protection for patients who underwent mitral valve surgery with coronary artery bypass grafting in our hospital. Further investigations extended to more cardiac surgery populations are needed to confirm clinical benefits of Custodiol cardioplegia.

Comparison of del Nido cardioplegia and St. Thomas Hospital solution - two types of cardioplegia in adult cardiac surgery.

IntroductionSt. Thomas’ cardioplegic solution No. 2 (ST), although most widely used in adult cardiac surgery, needs to be given at short intervals, causing additional myocardial injury.AimTo determine whether del Nido (DN) cardioplegia, with longer periods of arrest, provides equivalent myocardial protection as compared to ST.Material and methodsThe study population comprised 100 patients who underwent elective coronary artery bypass grafting (CABG) or double valve replacement (DVR) surgery between January 2015 and January 2016. The patients were divided into two groups based on the type of cardioplegia administered during surgery: 1) intermittent ST (ST, n = 50) and 2) DN cardioplegia (DN, n = 50). We compared the aortic cross clamp (CC) and cardiopulmonary bypass (CPB) times, number of intra-operative DC shocks required, and postoperative changes in left ventricular ejection fraction (LVEF) in the two groups.ResultsThe aortic cross clamp and bypass times were shorter with DN (110.15 ±36.84 vs. 133.56 ±35.66 and 158.60 ±39.92 vs. 179.81 ±42.36 min respectively, p < 0.05). Fewer cardioplegia doses were required in the DN group vs. the ST group (1.38 ±0.59 vs. 4.15 ±1.26; p = 0.001), while a single cardioplegia dose was given to 35 DN patients (70%) vs. 0 ST patients (p < 0.001). Postoperative LVEF was better preserved in the DN group.ConclusionsThe use of DN leads to shorter cross clamp and CPB times, reduces cardioplegia dosage, and provides potentially better myocardial protection in terms of LVEF preservation, with a safety profile comparable to ST cardioplegia.

Improved Myocardial Function After Cold Storage With Preservation Solution Supplemented With a Carbon Monoxide–Releasing Molecule (CORM-3)

Carbon monoxide-releasing molecules (CO-RMs) are pharmacologically active as they protect against cardiac graft rejection and cold ischemia-mediated renal dysfunction. We investigated the cardioprotective role of carbon monoxide (CO) released from CORM-3 against cold ischemia-mediated injury in the heart and evaluated its potential application in the clinical setting of cardiac transplantation. Isolated rat hearts underwent cold ischemic storage for 4 or 6 hours using St Thomas Hospital solution that was supplemented with either CORM-3 (50 mumol/liter) or its inactive counterpart (iCORM-3), which does not release CO. Hearts were then reperfused. Both functional parameters and release of cardiac enzymes were assessed. Addition of CORM-3 to the preservation solution resulted in a significant improvement in systolic and diastolic function as well as coronary flow when compared with hearts treated with iCORM-3. In addition, lower levels of the cardiac enzymes creatine kinase and lactate dehydrogenase were measured in the perfusate of hearts stored with CORM-3. The improved functional recovery and reduced enzyme release after cardiac cold storage with CORM-3, but not iCORM-3, indicate that CO is the main mediator of myocardial protection. Thus, CO-RMs can be used as adjuvants to improve the preservation of hearts for transplantation.

Cellular Electrophysiological and Mechanical Effects of Celsior Solution on Endothelial Function in Resistance Coronary Arteries

We investigated a relatively new organ preservation (Celsior) solution regarding its effect on the endothelium-derived hyperpolarizing factor (EDHF)-mediated function with comparison to St. Thomas Hospital (ST) solution. The EDHF-mediated relaxation was induced by bradykinin (BK, -10 to -6.5 logM) in the presence of inhibitors of nitric oxide and prostacyclin in porcine small resistance coronary arteries, before and after incubation in ST (Group Ia, n=11), Celsior (Group Ib, n=13), or Krebs (Group Ic, control, n=12) at 4 degrees C for 4 hr. The EDHF-mediated hyperpolarization of the membrane potential of smooth muscle cells was measured by microelectrode with simultaneous relaxation after cold storage in ST (IIa, n=7), Celsior (IIb, n=6), or Krebs (IIc, control, n=6), or followed by washout with Krebs (ST: IIIa, n=6, Celsior: IIIb, n=6). The EDHF-mediated relaxation was significantly decreased in Group Ia (56.4+/-7.2% vs. 71.2+/-5.3%, P<0.05) and Ib (44.8+/-4.9% vs. 74.7+/-3.3%, P<0.05) but not in Ic. The sensitivity to BK was also significantly decreased (Ia: -7.51+/-0.14 vs. -7.76+/-0.12 log M, P<0.05; Ib: -7.36+/-0.09 vs. -7.60+/-0.09 logM, P<0.05). The resting membrane potential was depolarized in IIa (-44.3+/-1.9 mV, n=7, P<0.05) and IIb (-33.0+/-2.2 mV, n=6, P<0.05) compared with IIc (-57.1+/-1.5 mV, n=6). The EDHF-mediated hyperpolarization decreased significantly in IIa and IIb (3.4+/-0.3 and 3.0+/-0.2 vs. 6.3+/-0.5 mV, P<0.05) and partially restored in IIIa (5.0+/-0.2 vs. 3.4+/-0.3 mV, P<0.05) and IIIb (4.1+/-0.3 vs. 3.0+/-0.2 mV, P<0.05). Storage with Celsior and ST solutions reduces the EDHF-mediated endothelial function (hyperpolarization and associated relaxation) in porcine small resistance coronary arteries.

The Na+/H+ Exchange Inhibitor Cariporide is Washed Out of the Myocardium by Crystalloid Cardioplegia

Inhibition of the Na (+)/H (+) exchanger (NHE) is cardioprotective, but dosage and timing of NHE-inhibitors are critical for their efficacy. We studied the effect of a new dosing regime of the NHE-inhibitor cariporide on myocardial function and damage after cardioplegic arrest (CPA) and determined its myocardial and serum concentrations. 3 pigs received a bolus of 180 mg cariporide intravenously (i. v.) and were sacrificed shortly thereafter to allow measurement of the myocardial concentrations of cariporide. Subsequently, 10 pigs were randomized to receive either i. v. cariporide (bolus followed by an infusion of 40 mg/h) or placebo. Cardiopulmonary bypass was initiated, and the heart was arrested for 60 minutes by infusion of St. Thomas Hospital solution. Left ventricular (LV) function was studied using microsonometry. Myocardial damage was assessed by troponin T. Serum concentrations of cariporide were measured throughout the study, and myocardial concentrations were measured before the end of CPA and 180 minutes thereafter. Cariporide was present in all myocardial specimens (median: 1.4 ng/mg) studied previously. In the main study, LV function or myocardial damage did not differ significantly between the groups at any time point. Stable serum cariporide concentrations were achieved (3.4 +/- 0.5 microg/ml). Cariporide was detectable in only one of the myocardial biopsies obtained before the end of CPA, but 180 minutes thereafter, the myocardial cariporide concentration was 2.5 +/- 0.3 ng/mg. We observed no effect of i. v. cariporide on LV function or myocardial damage after cardioplegic arrest. Our data suggest that cariporide is washed out of the myocardium by repeated application of crystalloid cardioplegia. Thus, the mode of delivery also appears to be critical for cardioprotection with NHE-inhibitors.

The role of antioxidant supplementation in cardiac transplantation: An experimental study in rats

Background We investigated three antioxidants, inositol hexaphosphate (IP6), superoxide dismutase (SOD), and catalase (CAT), using a Langendorf model of heart transplantation. Methods Rat hearts were mounted on a Langendorf perfusion apparatus with addition of IP6, SOD+CAT, IP6+SOD+CAT to St. Thomas Hospital solution (n = 6 for each) versus a control group (n = 6), not containing supplementation. Global ischemia was achieved for 6 hours. Results The worst peak-to-peak (PP) and +dp/dt maximum values were observed in the IP6+SOD+CAT group, the values being significantly lower than those in the SOD+CAT group. The lowest plasma creatine kinase (CK), CK-muscle-band (CK-MB), and lactate dehydrogenase levels were measured from the SOD+CAT group. The highest values for CK were in the control group, and those for CK-MB were in the IP6 group. The lowest myocardial malondialdehyde and adenosine triphosphate values were observed in the SOD+CAT group. Conclusions Supplementing St. Thomas Hospital solution with IP6 did not ameliorate myocardial damage following global ischemia. The contractility deteriorated further when IP6+SOD+CAT were used together; however, SOD+CAT improved cardiac mechanical functions, and significantly reduced myocardial damage.

The cardioprotection of rutaecarpine is mediated by endogenous calcitonin related-gene peptide through activation of vanilloid receptors in guinea-pig hearts.

Previous investigations have shown that calcitonin gene-related peptide (CGRP) protects against myocardial ischemia-reperfusion injury and that rutaecarpine activates vanilloid receptors to evoke CGRP release. In the present study, we examined whether rutaecarpine enhances preservation with cardioplegia in guinea-pig hearts, and whether the protective effects of rutaecarpine are related to stimulation of endogenous CGRP release via activating vanilloid receptors. The isolated guinea-pig heart was arrested using St. Thomas Hospital solution, and then reperfused with normothermic Krebs-Henseleit solution for 30 min after a 4-h hypothermic ischemic period. Hypothermic ischemia caused a decline in cardiac function (left ventricular pressure, +/-dp/dt(max), heart rate and coronary flow) and an increased release of creatine kinase during reperfusion. Rutaecarpine at the concentration of 1.0 microM significantly improved the recovery of cardiac function and reduced the release of creatine kinase during reperfusion after hypothermic ischemia. Rutaecarpine at the concentration of 3.0 microM significantly reduced the release of creatine kinase and increased the coronary flow, but only caused a slight improvement of left ventricular pressure, +/-dp/dt(max), heart rate during reperfusion. The cardioprotective effects of rutaecarpine were abolished by capsazepine, a competitive vanilloid receptor antagonist, or by CGRP (8-37), a selective CGRP receptor antagonist. Rutaecarpine at the concentration of 1.0 or 3.0 microM significantly increased the release of CGRP, which was also abolished by capsazepine. These results suggest that rutaecarpine enhances preservation with cardioplegia in guinea-pig hearts and that the protective effects of rutaecarpine are due to stimulation of endogenous CGRP release via activating vanilloid receptors.

Improvement of preservation with cardioplegic solution by nitroglycerin-induced delayed preconditioning is mediated by calcitonin gene-related peptide

Improvement of preservation with cardioplegic solution by nitroglycerin-induced delayed preconditioning was studied in the isolated rat heart. The isolated rat heart was arrested using St. Thomas Hospital solution, and then reperfused with normothermic Krebs–Henseleit solution for 40 min after a 4-h hypothermic ischemic period. Heart rate, coronary flow, left ventricular pressure and the maxium value of the first derivatives of left ventricular pressure (±d p/d t max) were recorded, and plasma concentrations of CGRP-like immunoreactivity (CGRP-LI) and nitric oxide (NO), tumor necrosis factor-alpha (TNF-α) in myocardial tissues, and creatine kinase in coronary effluent were measured. Delayed preconditioning was induced by i.v. injection of nitroglycerin 24 h before the experiment. Nitroglycerin (60 μg/kg or 120 μg/kg) caused an improvement of cardiac function, a decrease in the release of creatine kinase in coronary effluent and a decrease in the content of TNF-α in myocardial tissues. Nitroglycerin significantly increased plasma concentrations of CGRP and NO. After pretreatment with capsaicin, which depletes neurotransmitters in sensory nerves, or methylene blue, a selective guanylate cyclase inhibitor, the protection and the elevated release of CGRP induced by nitroglycerin were abolished. The present study suggests that improvement of preservation with cardioplegic solution by nitroglycerin-induced delayed preconditioning is due to stimulation of CGRP release in the rat heart, and that the protection of CGRP-mediated nitroglycerin is related to inhibition of TNF-α production.

Determinants and prognostic value of ischemic necrosis in early biopsies following heart transplant.

To evaluate the impact of early ischemic necrosis (IN) on the early and late outcome of heart transplantation, we reviewed our 11-year experience. Between January 1988 and June 1999, 207 heart transplants were performed in 205 patients (174 male and 31 female). Criteria for donor and recipient selection, and protocols for postoperative immunosuppression and rejection monitoring have remained unchanged over this period. Three different cardioplegic solutions were employed in graft preservation: St. Thomas Hospital solution in the earliest 31 cases (15%), University of Wisconsin solution in 96 cases (46.4%), and Celsior solution in the last 80 cases (38.6%). All patients who underwent at least one endomyocardial biopsy (176 patients) were divided into two groups according to the findings of IN within the early 3 postoperative months (group A, 49 patients with IN; group B, 127 patients without IN). The following variables were estimated in each group: donor and recipient age, ischemic time, type of cardioplegia, late mortality for cardiac causes, incidence of grade >2 rejection within the first 6 postoperative months, late incidence of grade >2 rejection, late incidence of NYHA class >II. No significant difference was found in any parameter between the two groups, except for the type of cardioplegic solution. A significantly higher incidence of ischemic necrosis in hearts preserved with St. Thomas solution was found (P < 0.001). Although pathology findings show that extracellular solutions carried a higher risk of early IN, no associated significant impairment in terms of late survival and event-free rate was observed in recipients with early IN.

No Beneficial Effects of Isocolloidoosmotic Synthetic Colloid Addition to St. Thomas Hospital Cardioplegic Solution in Ischemia-Reperfusion Injury in Isolated Perfused Rat Hearts

1. Cardioplegic solutions provide the opportunity to operate on a nonbeating heart and to protect the heart against ischemic injury during cardiac surgery. The components of these solutions are constantly being modified in an effort to find the optimal solution. We studied the effects of colloidal volume replacers such as dextran, HES and gelatin as an isocolloidoosmotic addition to St. Thomas Hospital cardioplegic solution in ischemia-reperfusion injury of isolated rat hearts. 2. In the control group, after a stabilization period of 20 min, the hearts were arrested with St. Thomas Hospital cardioplegic solution for 3 min, then subjected to 30 min of global ischemia. Hearts then were reperfused for 10 min. In the experimental groups, the protocol was the same, but either HES 200/0.5 (50 g/L), modified fluid gelatin (30 g/l) or dextran 70 (25 g/L) were added to the St. Thomas Hospital solution. 3. All hearts were compared for their preischemic and postischemic contractility, heart rate, contractility rate product, coronary flow, lactate dehydrogenase, creatine phosphokinase enzyme leakage and wet/dry weight ratio. 4. All groups had similar contractility (for control, HES, gelatin and dextran groups the values at minute 10 of reperfusion were 59±9, 56±11%, 61±14%, 49±14% of initial values [ P>0.05, respectively]) and enzyme leakage (lactate dehydrogenase 4.1±1.0, 8.1±1.5, 5.8±1.4, 3.7±1.2 [ P>0.05] and for creatine phosphokinase 3.9±2.5, 6.4±3.7, 5.5±1.3, 5.5±0.8, P>0.05] IU·min −1·g dry tissue −1 in the reperfusion period, respectively) results as compared with the control group. 5. The addition of isocolloidoosmotic colloids to the cardioplegic solution did not appear to enhance the effectiveness of the crystalloid St. Thomas Hospital cardioplegic solution. If a colloid is to be chosen as a plasma replacer or an additive to priming solution in the preoperative period, or during open-heart surgery, it should be modified fluid gelatin—for no sign of cardiodepression was determined with the use of this agent.

Effect of amino acid cardioplegia on myocardial metabolism and function of ischemic canine heart.

To evaluate the effect of amino acid cardioplegia on myocardial metabolism and function of ischemic canine heart, canine cardiopulmonary bypass (CPB) model was established and the dog heart was subjected to a 120 min ischemic arrest. Animals were divided into 3 groups, group 1: warm blood cardioplegia induction and terminal perfusion plus 4 C ST. Thomas hospital solution (STS) during ischemia; group 2: warm blood cardioplegia enriched with amino acid (L-asparte and L-glutamate 13 mmol/L each) and STS without amino acid (A. G.) and group 3: both warm blood cardioplegic solution and STS enriched with A. G. . The result demonstrated that the cardiac function of animals in group 2 and 3 had a significantly better recovery after ischemic-re-perfusion. By the end of ischemia the content of myocardial ATP in group 3 was distinctly higher than that in group 1 (P < 0.05), with the release of cardiac enzyme being the least. Myocardial ultra-structure almost remained intact before and after ischemia. Our experiment suggests that the cardioplegia arrest with warm blood and cold crystalloid solution enriched with amino acids could diminish the ischemia-re-perfusion injuries of the heart and enhance the effect of myocardial protection.

Simple 24-Hour Preservation of Rabbit Hearts with Hexanol and Pyruvate Cardioplegia

The effectiveness of a newly developed crystalloid cardioplegic solution containing 4 mM 1-hexanol and 10 mM pyruvate was compared with St Thomas' Hospital solution. After control perfusion with a Langendorff method, rabbit hearts ( n = 7 for each group) were arrested and stored in these solutions (4°C) for 24 h and subsequently reperfused for 45 min. The hexanol solution preserved both left ventricular systolic and diastolic function significantly better than St Thomas' Hospital solution. Developed pressure was significantly higher after preservation with the hexanol solution than with the St Thomas' Hospital solution a left ventricular balloon volumes larger than the mid volume ( P < 0.05). The maximum developed pressure after storage with the hexanol and St Thomas' Hospital solution were 77% and 42% of the maximum control values, respectively. Values for end-diastolic pressure at the maximum ventricular volume were 26.1 ± 9.8 and 66.7 ± 24.6 mmHg for the hexanol and St Thomas' Hospital solution, respectively ( P < 0.05). Creatine kinase release during the first 15 min of reperfusion was significantly lower with the hexanol solution as compared to St Thomas's Hospital solution (28.3 ± 8.3 vs 92.9 ± 52.6 IU/g wet weight, P < 0.05). In conclusion, a hexanol cardioplegic solution may be suitable for long-term cardiac preservation. Further evaluation of the effectiveness and safety of this solution is warranted.

Antagonisation of platelet activating factor--a new therapeutic concept for improvement of organ quality in lung preservation.

The release of platelet activating factor (PAF) is thought to be one of the most important pathophysiological pathways in the development of ischemic lung injury. We investigated the use of a PAF antagonist (PAF-a) in a canine model in reducing PAF-mediated pulmonary dysfunction following lung preservation and transplantation. Twelve combined heterotopic heart and orthotopic left lung allotransplantations were performed after 6 h of cold ischemia. Following administration of prostacyclin (PGI2), Euro-Collins solution (EC) was used for pulmonary artery flush in all donors, while in six animals the PAF-a, WEB 2170 BS, was administered to the donor (0.15 mg/kg for 30 min), to the storage solution (0.3 mg/kg) and to the recipient during reperfusion for a total of 6 h (0.3 mg/kg per h) EC/PAF-a). In all donors myocardial preservation was achieved using St. Thomas Hospital solution. Postoperatively, cardiorespiratory function was evaluated separately for donor and recipient organs at an FiO2 of 0.4 for a maximum of 12 h. The quality of lung preservation was assessed by means of postoperative oxygenation (pO2), pulmonary artery pressure (PAP) and pulmonary vascular resistance index (PVRI). In the EC/PAF-a group, pO2 of the donor lung was significantly elevated (P < 0.01) and PVRI was significantly lower (P < 0.05) when compared to the EC group, while PAP showed no significant differences between both groups and throughout the entire postoperative course. We concluded that a significant improvement in the current clinical standard for lung preservation could be obtained by the application of WEB 2170 BS in combination with EC flush as demonstrated by improved oxygenation and lower PVRI of the transplantated organs.

Antagonisation of platelet activating factor - a new therapeutic concept for improvement of organ quality in lung preservation

The release of platelet activating factor (PAF) is thought to be one of the most important pathophysiological pathways in the development of ischemic lung injury. We investigated the use of a PAF antagonist (PAF-a) in a canine model in reducing PAF-mediated pulmonary dysfunction following lung preservation and transplantation. Twelve combined heterotopic heart and orthotopic left lung allotransplantations were performed after 6 h of cold ischemia. Following administration of prostacyclin (PGI2), Euro-Collins solution (EC) was used for pulmonary artery flush in all donors, while in six animals the PAF-a, WEB 2170 BS, was administered to the donor (0.15 mg/kg for 30 min), to the storage solution (0.3 mg/kg) and to the recipient during reperfusion for a total of 6 h (0.3 mg/kg per h) EC/PAF-a). In all donors myocardial preservation was achieved using St. Thomas Hospital solution. Postoperatively, cardiorespiratory function was evaluated seperately for donor and recipient organs at an FiO2 of 0.4 for a maximum of 12 h. The quality of lung preservation was assessed by means of postoperative oxygenation (pO2), pulmonary artery pressure (PAP) and pulmonary vascular resistance index (PVRI). In the EC/PAF-a group, pO2 of the donor lung was significantly elevated (P < 0.01) and PVRI was significantly lower (P < 0.05) when compared to the EC group, while PAP showed no significant differences between both groups and throughout the entire postoperative course. We concluded that a significant improvement in the current clinical standard for lung preservation could be obtained by the application of WEB 2170 BS in combination with EC flush as demonstrated by improved oxygenation and lower PVRI of the transplantated organs.

University of Wisconsin versus modified Euro-Collins solution for lung preservation

In a canine model, the quality of lung preservation was assessed using pulmonary artery flush after prostacyclin administration with either modified Euro-Collins solution or University of Wisconsin solution. Twelve combined heterotopic heart and orthotopic left lung allotransplantations were performed after 6 hours of cold ischemia. Myocardial preservation was achieved using St. Thomas Hospital solution. Donor organs were anastomosed parallel to the recipient's heart and right lung, and the superior vena cava inflow was directed into the transplanted heart-left lung block after ligation of the recipient's superior vena cava proximal to the caval anastomosis. Postoperatively, cardiorespiratory function was evaluated separately for donor and recipient organs at an inspired oxygen fraction of 0.4 for a maximum of 12 hours. Significantly improved oxygenation and lower pulmonary vascular resistance index of the donor lung was observed in the University of Wisconsin + prostacyclin group, whereas pulmonary artery pressures showed no significant differences in between both groups. It is concluded that superior results in lung preservation can be achieved with pulmonary artery flush perfusion using University of Wisconsin solution and prostacyclin when compared with Euro-Collins solution and prostacyclin.

Effets vasculaires de la kétamine en présence d'une anesthésie par diazépam et fentanyl

Twenty-six adults undergoing elective cardiac surgery were anaesthetized with diazepam and fentanyl (induction with 200 μg · kg −1 and 30 μg · kg −1 respectively, maintenance with incremental doses). Normothermic constant perfusion output cardiopulmonary bypass was carried out with a membrane oxygenator, haemodilution with Ringer's lactate solution, and cardioplegia with St. Thomas's Hospital solution. The patients were randomly assigned to two groups. They were given either 2 mg · kg −1 of ketamine (group 1) or placebo (5 ml of normal saline) (group 2) via the venous line of the oxygenator. The non pulsatile flow was then kept at a steady rate of 2.41 · min −1 · m −2, and no other infusion or treatment was started during the study period (ten minutes). The mean arterial pressure and blood reservoir level were measured every min during this period. The systemic vascular resistances did not change significantly in either group, but remained 27 % lower in the ketamine group than in the placebo group (p < 0.01). The blood reservoir level was 37 % higher in the ketamine group (p < 0.01), suggesting a decreased venous capacitance. It is therefore concluded that ketamine leads to venous constriction, and probably arterial dilation, during fentanyl-diazepam anaesthesia and normothermic cardiopulmonary bypass. The venous effects of ketamine could explain why it is usually well tolerated in hypovolaemic states.

Myocardial preservation with the UW solution. First European results in clinical heart transplantation

In recent years, there is a growing body of evidence that the University of Wisconsin (UW) solution offers many advantages in organ preservation with regard to preservation quality and time. We, therefore, conducted the first European prospective, randomized, clinical trial comparing myocardial performance after preservation with UW and St. Thomas Hospital (ST) solution. Preliminary results indicated superior heart function after preservation with UW solution.

Comparison of UW-solution and St. Thomas hospital solution for prolonged myocardial protection by phosphorus-31 NMR spectroscopy

Comparison of UW-solution and St. Thomas hospital solution for prolonged myocardial protection by phosphorus-31 NMR spectroscopy

Oxygenation of cardioplegic solutions: A note of caution

The merits of oxygenated crystalloid cardioplegic solutions have been well established in experimental animals. The positive effects of oxygenation of Plasmalyte B (Sabax Ltd) and St. Thomas Hospital solution (Plegisol) were achieved by gassing with 95% O2/5% CO2 and 100% O2, respectively. In view of the marked pH differences induced by these gas mixtures, we evaluated the effect of mode of oxygenation on myocardial recovery during reperfusion after hypothermic cardioplegic arrest. Oxygenation with 100% O2 of Plasmalyte B containing high K+ levels caused marked deterioration in myocardial recovery, whereas the mode of oxygenation did not affect recovery after arrest with St. Thomas Hospital solution. Because the major differences between these solutions reside in their respective K+, Mg2+, and HCO3− contents, the effects of variations in the levels of these ions were investigated. The results showed that oxygenation with 100% O2 was deleterious only in the presence of high K+ (29 mmol/L), low Mg2+ (3 mmol/L), and high NaHCO3 (28 mmol/L) levels. The marked decline in mechanical recovery during reperfusion was associated with significant changes in myocardial adenosine triphosphate and intracellular Ca2+ levels. Although an explanation for these findings is not readily available, it is suggested that complex ionic interactions and possibly oxygen free radical generation may lead to intracellular Ca2+ overload, depression in mitochondrial adenosine triphosphate generation, and, hence, deterioration in mechanical recovery.

Ultrastructural study comparing the myocardial protective effects of four different infusates (Bretschneider's, St Thomas's, standard Ringer's and blood potassium solutions) in the human heart

Comparative mitochondrial ultrastructural changes during myocardial ischaemic periods have been assessed when using four different solutions: Bretschneider's solution (BS) (K+ = 10 mEq/l) at 4°C; St Thomas's hospital solution (STS) (K+ = 20 mEq/l) at 4°C; standard Ringer's solution (SRS) (K+ = 2.7 mEq/l) at 4°C; blood potassium cardioplegic solution (BPS) (K+ = 21 mEq/l) at 15°C. BS (n = 8), STS (n = 10), SRS (n = 8) and BPS (n = 8) were infused in 34 patients undergoing aortic valve replacement (n = 17) or aortocoronary bypass grafting (n = 17), after aortic crossclamping, either in the aorta or in both coronary ostia, until the septal myocardial temperature reached 10-13°C for crystalloid solutions or 15°C for blood cardioplegia. Myocardial biopsies were taken from the left ventricular apex, on a beating heart, at the beginning and end of bypass. To assess the degree of ischaemic injury, an ultrastructural evaluation of the mitochondria was done and four histological classes have been defined: class I- dense matrix and cristae; class II — occasional mitochondrial swelling; class III — decrease in matrix density with extensive swelling; class IV — severe swelling and/or rupture of matrix. This study showed that: (1) only the St Thomas's and Bretschneider's solutions provide a rapid electromechanical asystole; (2) isolated hypothermic crystalloid solution with low potassium concentration (standard Ringer) is not sufficient either to induce cardiac arrest or to prevent detrimental mitochondrial changes; (3) Bretschneider's solution appears to provide the best ultrastructural mitochondrial preservation during myocardial ischaemia.