[Clinical usefulness of new-generation pulse oximetry in the paediatric cardiac surgery setting]. / Utilisation clinique d'un oxymètre de pouls de nouvelle génération dans le cadre de la chirurgie cardiaque pédiatrique.

OBJECTIVES: Arterial oxygen saturation (SaO(2)) monitoring using pulse oximeter (SpO(2)) is mandatory in the intensive care unit. The aim was to assess bias and precision of new (SpO(2)ng) and old (SpO(2)og) pulse oximeter technologies in the postoperative period following pediatric cardiac surgery in cyanotic children. STUDY DESIGN: Prospective, monocentric. PATIENTS AND METHODS: Ten patients (7 days to 53 months old) were studied in the postoperative period following palliative cardiac surgery. SaO(2), SpO(2)og, and SpO(2)ng were obtained every 4 hours. SaO(2) of arterial blood sample was obtained from an intra-arterial catheter located in the radial artery, on the same side as the oximeters. Bias and precision were assessed using Bland-Altman analysis. RESULTS: We obtained 136 SaO(2) determinations. Mean SaO(2) was 76+/-15%. SpO(2)og was significantly different from SaO(2), while SpO(2)ng was not different from SaO(2). In 21 (15%) cases, SpO(2)og was not available whereas SpO(2)ng was available in 136 (100%) cases. In the remaining 115 cases, SpO(2)ng's precision was significantly better than SpO(2)og's precision. DISCUSSION: SpO(2)ng is more accurate and more reliable than SpO(2)og for SaO(2) monitoring in the postoperative period following pediatric cardiac surgery in cyanotic children.

Better preservation of endothelial function and decreased activation of the fetal renin-angiotensin pathway with the use of pulsatile flow during experimental fetal bypass.

OBJECTIVE: Pulsatile flow was shown to overcome the progressive rise in peripheral and placental vascular resistances observed during steady-flow bypass, this rise being counteracted by inhibition of nitric oxide synthase. This study quantifies the release of endothelial vasoactive substances during a 60-minute in utero model of fetal bypass. METHODS: Fetuses were randomly allocated into 1 of 2 groups (steady flow, n = 8, or pulsatile flow, n = 13) and subjected to bypass through central cannulation and perfusion with either a centrifugal or pulsatile (125 beats x min(-1)) blood pump. RESULTS: Lactate concentration was high, starting at fetal exteriorization and increasing during fetal preparation in the 2 groups. Once bypass was established, the rise was significant only in the steady-flow group. Plasma nitric oxide metabolites, similar before bypass, reached higher levels during pulsatile flow at the end of bypass (99+/-9 vs. 82+/-23 micromol x L(-1); P =.037). Levels of urinary nitric oxide metabolites were significantly higher in the pulsatile-flow than in the steady-flow group (764+/-143 vs. 508+/-240 micromol x L(-1); P =.005). Plasma cyclic guanosine monophosphate levels increased after 30 minutes of bypass in the pulsatile-flow group (25+/-18 vs. 12+/-8 pmol x mL(-1); P =.004), and urinary cyclic guanosine monophosphate excretion was higher in the pulsatile-flow group (517+/-450 vs. 118+/-78 pmol x mL(-1); P =.024). Plasma endothelin-1 levels increased in the 2 groups and were higher in the steady-flow group at 30 minutes (27+/-5 vs. 23+/-2 pg x mL(-1); P =.04) and 60 minutes of bypass (39+/-7 vs 32 +/- 6 pg x mL(-1); P =.04). Plasma renin concentration increased significantly during bypass only in the steady-flow group (26+/-10 vs. 57+/-42 in ng A1 x mL(-1) x h(-1); P =.04). CONCLUSIONS: Improved placental and peripheral perfusion during fetal pulsatile-flow bypass may be mediated by preservation of fetal/maternal endothelial nitric oxide biosynthetic mechanisms and/or decreased activation of the fetal renin-angiotensin pathway.

[Anesthesia consultation in cardiovascular and thoracic surgery. A survey of patient and physician satisfaction]. / Consultation d'anesthésie de chirurgie cardiovasculaire et thoracique. Enquête de satisfaction des patients et des médecins.

OBJECTIVE: To assess the quality of the preadmission anaesthetic consultation prior to cardiovascular and thoracic surgery with a satisfaction inquiry. STUDY DESIGN: Prospective study with a questionnaire, extended over a period of two months. PERSONS: Patients and anaesthetists of the cardiothoracic surgical service. METHODS: The inquiry, which took place after completion of the consultation was achieved by a person non member of the staff. Anaesthetists were questioned on the medical content, its exhaustive character and its value for the patient's perioperative care. RESULTS: Out of the 273 patients included in the study, 121 agreed to answer the questionnaire. Participation in the study was more significant in older patients (58 +/- 20 vs 51 +/- 24 years) and following shorter waiting time (WT) [15 +/- 13 (0-60) vs 25 +/- 18 (0-66) min]. The duration of the consultation (DC) was not different between the two groups [29 +/- 12 (8-70) vs 31 +/- 14 (6-75) min]. However patients' participation increased when the DC exceeded by 0.6 the sum of DC and WT [DC > 0.6 (DC + WT)]. The analogic score (AS) assessing reduction in preoperative anxiety was 8.4 +/- 1.5 (2-10). Finally, 108 patients out of 121 considered to have been well informed about the anaesthetic [AS = 8.7 +/- 1.2 (4-10)], 113 considered the preadmission consultation as a useful procedure [AS = 8.6 +/- 1.5 (2-10)]) and for 41 a personalized follow-up by the same anaesthetist was valuable. Only three operations had to be postponed the day before surgery. One third of the anaesthetists considered that the consultation improved the clinical and therapeutic management of the patients. CONCLUSION: This inquiry showed that the preadmission anaesthesia consultation was considered as benefitful by patients and anaesthetists. However the participation of patients in this study was poor. Subsequently to the inquiry information forms have been produced and handed to the patient prior to the consultation.

Video-assisted tricuspid valve surgery: a new surgical option in endocarditis on pacemaker.

A patient presenting with a pacemaker lead infection and tricuspid regurgitation underwent a minimally invasive video-assisted tricuspid valve replacement. The valve was approached through a right anterior mini thoracotomy. Under thoracoscopic vision and peripheral cardiopulmonary bypass, a catheter was placed on the ascending aorta for antegrade cardioplegia delivery. A transthoracic aortic cross-clamp was introduced through the third right intercostal space. Tricuspid valve replacement added to the pacemaker leads ablation was exclusively performed under thoracoscopic vision, providing an excellent video-image in this reduced operative field. After 22 months of follow up, the patient is asymptomatic, the echocardiography showing a normally functioning valve.

Long-term clinical and hemodynamic evaluation of porcine valved conduits implanted from the right ventricle to the pulmonary artery.

OBJECTIVE: This retrospective study was initiated to evaluate the long-term results of valved prosthetic conduits implanted in the right ventricular outflow tract in patients with complex ventricular-pulmonary discontinuity. METHODS: A cohort of 103 patients out of 127 (24 early deaths, 19%) operated on between 1973 and 1996 with porcine valved conduits was available for evaluation, with a follow-up ranging from 1 to 21.6 years (mean follow-up 8.4 +/- 6 years). A total of 74 hemodynamic studies were performed after the operation, 50 patients having undergone at least 1 cardiac catheterization during the follow-up period. RESULTS: There were 16 late deaths, and the actuarial survivals, including early mortality, were 72.9% +/- 4% at 5 years, 63.1% +/- 5% at 10 years, and 58.2% +/- 5% at 15 years, at which time 20 patients were still available for review and exposed to the risk of dying. The mean peak systolic gradient across the right ventricular outflow tract was plotted as a function of time, showing a gradual increase and a significant step-up after the eighth year, from 43 +/- 36 to 69 +/- 19 mm Hg (P < .005). Reoperation was required for progressive conduit obstruction between 1.1 and 17.7 years after implantation (mean 7.4 +/- 4.8 years) in 25 patients (24%, 70% CL 15%-33%), with generally very few symptoms, or for residual ventricular septal defect in 3 patients. Freedom from reoperation was 79.5% +/- 5% at 10 years and 65.8% +/- 7% at 15 years. CONCLUSIONS: Porcine conduits may represent a valuable alternative to biologic substitutes with similar long-term results. Given the few symptoms, progressive conduit stenosis after the eighth postoperative year imposes a yearly noninvasive patient evaluation during the follow-up.

Effects of various flow types on maternal hemodynamics during fetal bypass: is there nitric oxide release during pulsatile perfusion?

OBJECTIVE: This study investigates the role of various flow conditions on maternal hemodynamics during fetal cardiopulmonary bypass. METHODS: Normothermic fetal bypass was conducted under pulsatile, or steady flow, for a 60-minute period. Fetal lamb preparations were randomly assigned to 1 of the 3 groups: steady flow (n=7), pulsatile flow (n=7), or pulsatile blocked flow bypass (n=7), where fetuses were perfused with Nomega-nitro-L-arginine after the first 30 minutes of pulsatile flow to assess the potential role of endothelial autacoids. RESULTS: Maternal oximetry and pressures remained unchanged throughout the procedure. Under fetal pulsatile flow, maternal cardiac output increased after 20 minutes of bypass and remained significantly higher than under steady flow at minute 30 (8.8+/-0.7 L x min(-1) vs 5.9+/-0.5 L x min(-1), P=.02). Maternal cardiac output in the pulsatile group also remained higher than in both steady and pulsatile blocked flow groups, reaching respectively 8.7+/-0.9 L x min(-1) vs 5.8+/-0.4 L x min(-1) (P=.02) and 5.9+/-0.3 L min(-1) (P=.01) at minute 60. Maternal systemic vascular resistances were significantly lower under pulsatile than under steady flow after 30 minutes and until the end of bypass (respectively, 9.1+/-0.6 IU vs 12.7+/-1.1 IU, P=.02 and 8.9+/-0.5 IU vs 12.9+/-1.2 IU, P=.01). Infusion of Nomega-nitro-L-arginine was followed by an increase in systemic vascular resistances from 9.3+/-0.7 IU, similar to that of the pulsatile group, to 13.5+/-1 IU at 60 minutes, similar to that of the steady flow group. CONCLUSIONS: Maternal hemodynamic changes observed under fetal pulsatile flow are counteracted after infusion of Nomega-nitro-L-arginine, suggesting nitric oxide release from the fetoplacental unit under pulsatile fetal flow conditions.

The hemodynamic effects of hypoxemia in anesthetized pigs: a comparison between right heart catheter and echocardiography.

UNLABELLED: During hypoxemia, hypoxic pulmonary vasoconstriction and tachycardia are often observed in association with increases in pulmonary artery pressure and cardiac output. Nevertheless, the hemodynamic consequences of hypoxemia have never been evaluated by echocardiography and simultaneously compared with invasive hemodynamic variables. Fourteen open-chest, anesthetized piglets (weight 29-36 kg) were submitted to progressive hypoxemia and reoxygenation. Usual invasive hemodynamic variables were obtained from peripheral and central heart catheters. Direct epicardial echocardiography was used to measure right and left ventricular areas on a short-axis view at mid-papillary level. The mean pulmonary artery pressure (MPAP) increased with pulmonary vascular resistance in a dose-related manner as the fraction of inspired oxygen (FIO2) declined from 0.5 to 0.12. The MPAP correlated with right ventricular end-diastolic area (RVEDA) only at FIO2 0.08. There was a 49% reduction in left ventricular end systolic wall stress (LVESWS) between FIO2 0.5 and 0.08. Left ventricular ejection fraction area (LVEFA) increased by 33% above baseline and correlated with the decrease in LVESWS. No correlation was observed between left ventricular end-diastolic area and pulmonary artery occlusion pressure or left atrial pressure and between cardiac output and LVEFA. Systemic vascular resistance underestimates the magnitude of changes in LVESWS but overestimates the afterload compared with LVESWS. This study demonstrates that, for the lowest FIO2 (0.08), changes in MPAP correlated with changes in RVEDA but not in pulmonary vascular resistance. Moreover, LVESWS decreases significantly in a dose-related manner under progressive hypoxemia and normalizes immediately after reoxygenation. This study also shows that, under hypoxemic conditions, echocardiography enhances understanding of hemodynamic changes compared with right heart catheterization alone. IMPLICATIONS: Acute hypoxemia in pigs is responsible for pulmonary vasoconstriction-induced pulmonary hypertension (which is restricted by the right ventricular failure), as well as a PaO2-dependent decrease in left ventricular afterload. These changes are better displayed by echocardiography than by right heart catheter.

Experimental right ventricle to pulmonary artery discontinuity: outcome of polyurethane valved conduits.

OBJECTIVE: The ideal substitute for the treatment of ventricle-pulmonary artery discontinuity remains a topic of controversy, because of calcifications and degeneration of biologic substitutes leading to subsequent reoperations. Because polyurethane valves used in ventricular assist devices show a satisfactory biocompatibility, the aim of this study was to evaluate a valved conduit composed of a Dacron graft incorporating a trileaflet 25 mm polyurethane valve. METHODS: The conduit was implanted between the right ventricle and the main pulmonary artery in adult sheep, with ligation of the proximal pulmonary artery. The animals received no medications. Serial hemodynamic data were collected at the time of implantation and at postoperative intervals of 6 and 12 months. RESULTS: The peak pressure gradient across the valve increased significantly between implantation (0.17 +/- 5.6 mm Hg) and 6 months after operation (7.3 +/- 3 mm Hg, p = 0.0007) and remained stable thereafter (6.7 +/- 3 mm Hg at 12 months), whereas the cardiac output remained unchanged (4.6 +/- 0.6 L/min at implantation, 4 +/- 0.6 L/min at 6 months, and 3.9 +/- 1.1 L/min at 12 months). At the completion of the study, valve samples were processed and vapor coated with carbon for microscopic examination. There was one instance of nonadherent thrombus formation inside a cusp but no structural failures. The other valves were free of calcium deposits and no significant amounts of phosphorus could be detected by scanning electron microscopy and energy dispersive spectrometry. CONCLUSIONS: These data demonstrate the good hemodynamic performance, low thrombogenicity, and acceptable durability of the polyurethane valves implanted in the right side of the heart in a chronic sheep model.

Flow-induced release of endothelium-derived relaxing factor during pulsatile bypass: experimental study in the fetal lamb.

OBJECTIVE: This study was initiated to test the hypothesis that fetal hemodynamic changes observed under pulsatile flow bypass might be related to the release of endothelium-derived relaxing factor through oscillating shear stress. METHODS: Normothermic bypass was instituted in utero in 21 preterm fetal lambs for a 1-hour period through the right atrium and main pulmonary artery. Ultrasonic flowmeters were positioned around the descending aorta and the umbilical artery. The circuit consisted of an oxygenator and a pump set to either continuous flow (n = 7) or pulsatile flow (n = 7) and adjusted to maintain a fetal main arterial pressure of 50 mm Hg. In seven other animals, endothelium-derived relaxing factor was blocked by a continuous infusion of N omega-nitro-L-arginine after 30 minutes of pulsatile flow. RESULTS: During the first 30 minutes of bypass, pump flows were significantly lower in the continuous-flow group than in the pulsatile-flow or blocked-flow groups (respectively, 612 +/- 144, 907 +/- 153 and 987 +/- 228 ml/min), with similar changes in aortic and umbilical flows. Systemic vascular resistances were significantly lower in the pulsatile-flow and blocked-flow groups than in the continuous-flow group (550 +/- 106 vs 821 +/- 212 dynes/sec/cm-5). However, after blockade of endothelium-derived relaxing factor, resistances increased gradually in the blocked-flow group to reach the level of that of the continuous-flow group at the end of bypass (943 +/- 77 vs 556 +/- 143 dynes/sec/cm-5 in the pulsatile-flow group). CONCLUSIONS: Blockade of endothelium-derived relaxing factor after 30 minutes of pulsatile flow returns fetal hemodynamics to continuous flow conditions. The specific inhibitor of endothelium-derived relaxing factor used in this experiment suggests that nitric oxide may be released by fetal endothelium during pulsatile bypass.

Predictive factors for usefulness of fiberoptic pulmonary artery catheter for continuous oxygen saturation in mixed venous blood monitoring in cardiac surgery.

The main goal of this prospective study was to identify among cardiac surgery patients, usually monitored through a standard pulmonary artery catheter (PAC), those in whom a fiberoptic catheter oximeter to measure oxygen saturation in mixed venous blood (SVO2 PAC) would be most useful. Data from 286 patients who underwent coronary artery bypass graft (50%) or valvular surgery were recorded, including ASA physical status, New York Heart Association (NYHA) classification, and Parsonnet score (PS). Hemodynamic events and SVO2 changes were collected intra- and postoperatively until weaning from mechanical ventilation. The anesthesiologist in charge graded the usefulness of SVO2 PAC, and another anesthesiologist carried out a blindly controlled overall evaluation. Usefulness was defined as the presence of a change in therapeutic maneuver triggered solely by continuous SVO2 data that would not have occurred based on other routine parameters. SVO2 was also considered useful if earlier recognition of significant adverse events occurred. SVO2 PAC was useful in 57% of the patients. Independent predictive factors (multivariate analysis) for the perioperative usefulness of SVO2 in the whole population consisted of ASA class > or = 4 (P < 10(-5); relative risk [RR] 1.78, 1.51-2.07), mitral surgery (P < 10(-4); RR 1.72, 1.4-2.02), and NYHA score > or = 3 (P < 0.01; RR 1.66, 1.35-2.05). Independent predictive factors for the perioperative usefulness of SVO2 in the coronary artery bypass graft population were NYHA score > or = 3 (P < 10(-5); RR 1.90, 1.42-2.55) and ASA class > or = 4 (P < 0.01; RR 1.99, 1.51-2.63). The presence of three stenosed coronary arteries showed borderline significance (P < 0.06). Independent predictive factors for perioperative usefulness of SVO2 in the valvular population were mitral pathology (P < 10(-5)) and ASA class > or = 4 (P < 0.01). The receiver operator characteristic curve assessed the predictivity of the PS. SVO2 PAC was more useful in the group of patients with the greatest severity of illness (PS in useful group 17.0 +/- 10.3; in nonuseful group 8.7 +/- 6.6; P < 10(-4)). Intensive care unit duration and hospital stay in the useful group was prolonged compared with the nonuseful group. Similarly, morbidity was frequent in the useful group, although it was not always significantly different from the nonuseful group according to the type of complications. Mortality was comparable in the groups despite their different degree of illness and was reduced when taking into account the predictive and observed mortality provided by the PS. This study defined independent preoperative factors associated with SVO2 PAC monitoring and proposed a cutoff point above which SVO2 may be useful.

Glucose versus lactated Ringer's solution during pediatric cardiac surgery.

OBJECTIVE: Whether intraoperative fluid infusion should contain glucose during pediatric cardiac surgery remains controversial. This study was performed to compare the effects of glucose and glucose-free solutions on blood glucose and blood insulin levels during total repair of congenital heart diseases. DESIGN: Prospective randomized and blinded study. SETTING: Cardiovascular university center. PARTICIPANTS: Forty nondiabetic children, weight ranging from 4 to 10 kg, scheduled for cardiac surgical procedures requiring cardiopulmonary bypass (CPB) without total circulatory arrest. INTERVENTIONS: Group R (n = 20) was administered lactated Ringer's solution intraoperatively, and group G (n = 20) received 5% glucose. Fluids were infused at a rate of 3 mL/kg/h in the two groups from the induction of anesthesia to the end of the surgical procedure. Blood glucose and insulin were sampled before infusion (Tzero), before CPB (T1), 10 minutes after initiation of CPB (T2), 10 minutes after initiation of rewarming (T2), and at the end of the procedures (T4). Postoperatively, blood glucose was measured at the first, 12th, and 24th hours. MEASUREMENTS AND RESULTS: During the prabypass period, three children in group R had severe hypoglycemia (blood glucose < 40 mg/dL). After initiation of CPB, blood glucose increased in both groups, with a small difference at the end of the procedure. No infants in the two groups had blood glucose higher than 239 mg/dL. CONCLUSIONS: Glucose withdrawal during pediatric cardiac surgery induces threatening hypoglycemia during the prabypass period, and moderate intraoperative glucose administration (2.5 mg/kg/min) is not responsible for major hyperglycemia.

[Left ventricular assistance by postoperative mechanical devices in neonates]. / Réentraînement ventriculaire gauche par assistance mécanique postopératoire chez le nouveau-né.

Circulatory assistance in children and neonates has not been extensively reported. It poses specific problems related mainly to miniaturisation of systems. The authors report three cases of left ventricular assistance with the Biomedicus centrifugal pump followed by functional recovery in neonates operated for d-transposition of the great arteries. The assistance was installed by cannulation of the left atrial appendage and the ascending aorta, the canules being connected to the Biomedicus pump. The duration of assistance was 53, 116 and 120 hours respectively. The beginning of left ventricular recovery was observed after 24, 48 and 70 hours of assistance and the patients were weaned of assistance under stable haemodynamic conditions. One of the major problems during the period of assistance is decoagulation, 2 out of 3 patients requiring removal of thrombi during the first 12 hours of assistance. On the other hand, no cases of systemic embolism or thrombosis in the pump itself were observed. Decoagulation was maintained by continuous intravenous heparin with an initial dosage of 5 U/kg/h adapted to the activated cephalin time and anti Xa levels measured every 6 hours. No infectious complication was observed and the sternal wound healed satisfactorily despite systematic delayed closure of the thorax. The quality of results requires cooperation of a surgical infrastructure used to techniques of circulatory assistance, a well equipped neonatal intensive care unit and a permanently accessible laboratory for monitoring coagulation status.

Mechanical valve in aortic position is a valid option in children and adolescents.

OBJECTIVE: The choice of a valve substitute remains a challenge in young patients, with numerous reports of early degeneration and calcification of biological valves in this age group. Therefore an assessment of the long-term results after mechanical aortic valve replacement in children was initiated. METHODS: A retrospective study was conducted in 54 consecutive patients aged 1.1 to 17 years (mean 12.8 +/- 4 years) operated on between 1975 and 1993. Aetiology was congenital in 34 patients, rheumatic in 13, infectious in 5, and dystrophic in 2. Concomitant surgery included mitral valve replacement (10), aortic annulus enlargement (9), correction of truncus arteriosus (7), Bentall operation (2), coarctation repair (2), tricuspid valvuloplasty (2), correction of double outlet right ventricle (1), and replacement of a right ventricle to pulmonary artery conduit (1). A Bjork-Shiley valve was implanted in 14 patients, and a St Jude Medical valve in 40. All patients were given Warfarin with a monthly INR control. Follow-up was completed through questionnaires mailed to referring physicians and direct clinical examination. RESULTS: Overall early mortality was 13% (7 cases), and 6% (2 cases) in the 32 patients operated on after 1984. Follow-up was complete in 45 survivors (2 lost to follow-up), with a total follow-up of 261 patient-years. There were 6 late deaths, 4 being cardiac and due to persistent LV dysfunction, and 2 valve-related, due respectively to major gastro-intestinal bleeding and massive thromboembolism. Linearized rates of valve thrombosis and anticoagulant-related hemorrhage were both 0.3% per patient-year. Actuarial survival rate was respectively 84.5% at 5 years and 70.2% at 10 years. Reoperation was necessary in 3 patients for recurrent LV outflow tract obstruction. One patient with severe LV dysfunction is awaiting a heart transplant. CONCLUSION: We conclude that the longterm outcome after mechanical aortic valve replacement in children and adolescents is satisfactory and comparable to currently available reports on biological substitutes. The mandatory anticoagulant therapy is well tolerated in this age group.

Effect of trimetazidine on postischemic regional myocardial stunning in the halothane-anesthetized dog.

Trimetazidine (TMZ) has been described as a new antiischemic agent. Whereas its precise mechanism of action remains unknown, antioxidant properties and the ability to preserve high-energy phosphate metabolism have been reported. Accordingly, we studied whether TMZ may limit postischemic regional myocardial stunning (known to be caused by reactive oxygen species) and influence recruitment of contractile reserve by inotropic stimulation in a dog model, using halothane to maintain steady anesthesia throughout the experiment. Dogs were submitted to a 15-min coronary artery occlusion followed by reperfusion. The blinded protocol included a 3-day oral pretreatment (1 mg/kg/day), a bolus injection (0.5 mg/kg), followed by intravenous infusion (0.5 mg/h) initiated 15 min before coronary artery occlusion. Despite lower heart rate (HR) and significant reduction of lipid peroxidation in treated dogs, myocardial stunning and recruitment of contractile reserve by dobutamine infusion in the postischemic myocardium were not modified by TMZ. Adenine nucleotide pool in the postischemic myocardium was considerably reduced as compared with the nonischemic myocardium in both groups. Therefore, in halothane-anesthetized dogs, the antioxidant properties of TMZ were not sufficient to protect myocardium in terms of postischemic dysfunction after 15-min ischemia.

Transesophageal echocardiographic assessment of left ventricular function in brain-dead patients: are marginally acceptable hearts suitable for transplantation?

BACKGROUND: The brain-dead donor supply has become one of the criteria limiting the performance of heart transplantation. Conventional screening criteria are too limiting and exclude suitable heart donors. Echocardiography is now widely available and is a reliable tool to assess left ventricular dysfunction in brain-dead donors. Yet few data are available on the degree of left ventricular dysfunction where a transplantation is possible. METHODS: Fifty-five potential brain-dead heart donors (age 38 +/- 11 years) were prospectively evaluated by transesophageal echocardiography (TEE) before harvesting. Fractional area change (FAC) was used to assess left ventricular function in potential brain-dead donors. Transplanted hearts were evaluated on the fifth postoperative day. The transplantation was considered a success if the recipient was alive, not retransplanted, without an assistance device or an epinephrine infusion of more than 1 mg/h and showed an ejection fraction above 40%. RESULTS: Of the 55 potential heart donors, 20 exhibited an FAC of less than 50%. Forty hearts were harvested, 36 of which were successfully transplanted. Nine patients had an FAC below 50% (group H2) and 27 had an FAC over 50% (group H1). Four patients died: 2 from hemorrhage (FAC > 50% in donors); 1 from right and one from left ventricular dysfunction (FAC < 50% in donors). The FAC increased significantly from 51 +/- 15% to 57 +/- 11% in 18 hearts that underwent TEE in donors and afterwards in recipients. Overall actuarial survival was 86.2% versus 64.6% at 1 and 2 years in group H1 and group H2, respectively (p = NS). CONCLUSIONS: TEE is useful to assess left ventricular function in potential brain-dead donors. An FAC less than 50% is present in 36% of potential heart donors. Because left ventricular dysfunction is often reversible shortly after transplantation, an FAC below 50% may not necessarily preclude the use of hearts for transplantation.

Myocardial protection during coronary artery bypass graft surgery: a randomized, double-blind, placebo-controlled study with trimetazidine.

We conducted a randomized, double-blind, placebo-controlled study to assess the cardioprotective effects of trimetazidine (TMZ), an antiischemic drug, on left ventricular function using transesophageal echocardiography (TEE) after coronary artery bypass grafting (CABG). Forty patients undergoing elective CABG received either TMZ or a placebo (PCB). The primary measures of efficacy were serial measurements of fractional area change (FAC), percent of systolic wall thickening (SWT), and malonedialdehyde (MDA) production. The two groups were similar for the following variables: number of vessels revascularized (2.5 +/- 0.2 in the TMZ group and 2.8 +/- 0.1 in the PCB group), duration of aortic clamping (46 +/- 4 min in the TMZ group and 48 +/- 3 min in the PCB group), and bypass time (63 +/- 4 min in the TMZ group and 70 +/- 4 min in the PCB group). FAC increased by 12% in both groups 20 min after aortic unclamping (P < 0.05) and remained above the initial value at the sixth postoperative hour. SWT was 23.8% +/- 1.6%, 25.4% +/- 1.9%, then 21.6% +/- 1.5% in the TMZ group and 22.8% +/- 1.6%, 23.8% +/- 1.4%, then 22.3% +/- 1.6 % in the PCB group, after induction of anesthesia and 1 and 6 h after aortic unclamping (not significant). MDA increased by 24% in the PCB group and 25% in the TMZ group 20 min after aortic unclamping (P < 0.01). Lactate levels were lower in the TMZ group (P < 0.05) and patients from the TMZ group received less intravenous calcium before aortic clamping (P < 0.02) and less calcium channel entry blocking drugs in the early phase after aortic unclamping (P < 0.01) compared to the PCB group. We conclude that in patients with good preoperative ejection fraction undergoing CABG, TMZ as administered did not demonstrate clinically significant cardioprotective effects on left ventricular performance and lipid peroxidation compared to PCB.

[Hemodynamics of right circulation in ewes: normal values]. / Hémodynamique de la circulation droite chez la brebis: valeurs normales.

The right cardiac pressure was measured on 24 anesthetized adult ewes (Halothane) with a Swan Ganz catheter. After a review of the catheterization technique, the results (mean +/- standard deviation) in mmHg were: right auricle 17 +/- 5, right ventricle 30 +/- 6 (systolic) and 12 +/- 6 (telediastolic), pulmonary artery 29 +/- 6 (systolic), 13 +/- 6 (diastolic) and 20 +/- 6 (mean), capillary pressure 17 +/- 7. We observed slight variations in the pressure curve morphology compared to those found for man and the pressures were 5-10 mmHg higher than what is observed in man and slightly higher than those observed in dogs. These results also demonstrate a great variation between animals.