E. Rainer de Vivie

Risk stratification in heart surgery: comparison of six score systems

OBJECTIVE Risk scores have become an important tool in patient assessment, as age, severity of heart disease, and comorbidity in patients undergoing heart surgery have considerably increased. Various risk scores have been developed to predict mortality after heart surgery. However, there are significant differences between scores with regard to score design and the initial patient population on which score development was based. It was the purpose of our study to compare six commonly used risk scores with regard to their validity in our patient population. METHODS Between September 1, 1998 and February 28, 1999, all adult patients undergoing heart surgery with cardiopulmonary bypass in our institution were preoperatively scored using the initial Parsonnet, Cleveland Clinic, French, Euro, Pons, and Ontario Province Risk (OPR) scores. Postoperatively, we registered 30-day mortality, use of mechanical assist devices, renal failure requiring hemodialysis or hemofiltration, stroke, myocardial infarction, and duration of ventilation and intensive care stay. Score validity was assessed by calculating the area under the ROC curve. Odds ratios were calculated to investigate the predictive relevance of risk factors. RESULTS Follow-up was able to be completed in 504 prospectively scored patients. Receiver operating characteristics (ROC) curve analysis for mortality showed the best predictive value for the Euro score. Predictive values for morbidity were considerably lower than predictive values for mortality in all of the investigated score systems. For most risk factors, odds ratios for mortality were substantially different from ratios for morbidity. CONCLUSIONS Among the investigated scores, the Euro score yielded the highest predictive value in our patient population. For most risk factors, predictive values for morbidity were substantially different from predictive values for mortality. Therefore, development of specific morbidity risk scores may improve prediction of outcome and hospital cost. Due to the heterogeneity of morbidity events, future score systems may have to generate separate predictions for mortality and major morbidity events.

Effects of chronic atrial fibrillation on gap junction distribution in human and rat atria.

OBJECTIVES To elucidate the structural basis for the electrophysiologic remodeling induced by chronic atrial fibrillation (AF), we investigated connexin40 and connexin43 (Cx40 and Cx43) expression and distribution in atria of patients with and without chronic AF and in an animal model of AF with additional electrophysiologic investigation of anisotropy (ratio of longitudinal and transverse velocities). BACKGROUND Atrial fibrillation is a common arrhythmia that has a tendency to become persistent. Since gap junctions provide the syncytial properties of the atrium, changes in expression and distribution of intercellular connections may accompany the chronification of AF. METHODS Atrial tissues isolated from 12 patients in normal sinus rhythm at the time of cardiac surgery and from 12 patients with chronic AF were processed for immunohistology and immunoblotting for the detection of the gap junction proteins. The functional study of the cardiac tissue anisotropy was performed in rat atria in which AF was induced by 24 h of rapid pacing (10 Hz). RESULTS Immunoblotting revealed that AF did not induce any significant change in Cx43 content in human atria. In contrast, a 2.7-fold increase in expression of Cx40 was observed in AF. Immunohistologic analysis indicated that AF resulted in an increase in the immunostaining of both connexins at the lateral membrane of human atrial cells. A similar spatial redistribution of the Cx43 signal was seen in isolated rat atria with experimentally-induced AF. In addition, AF in rat atria resulted in decreased anisotropy with slightly enhanced transverse conduction velocity. CONCLUSIONS This experimental study showed that AF is accompanied by spatial remodeling of gap junctions that might induce changes in the biophysical properties of the tissue.

Cardiac surgery in patients with end-stage renal disease: 10-year experience

BACKGROUND End-stage renal disease is known to be an important risk factor complex for cardiac operations performed with cardiopulmonary bypass. METHODS To investigate the influence of preoperative status on perioperative mortality and morbidity, we retrospectively analyzed data from 65 patients (20 women and 45 men with a mean age of 58.8+/-10.0 years [+/-standard deviation]) with end-stage renal disease who were on dialysis and who underwent a cardiac surgical procedure between 1988 and 1998. RESULTS Fifty-one percent of the patients had isolated coronary artery bypass grafting, 35% had replacement or reconstruction of one valve or two valves, and 14% underwent combined coronary artery bypass grafting and valve replacement. The perioperative mortality rate was 13.8% with 78% (7 of 9) of deaths occurring in patients having a valve procedure. Six of the 9 patients who died had compromised left ventricular function preoperatively, and all 9 were in New York Heart Association class III or IV. Mean preoperative duration of dialysis was longer (80+/-70 months) in the 9 patients who died compared with that in the surviving 56 patients (45+/-49 months) (p = 0.05). We found dyspnea at rest, duration of dialysis of 60 months or more, combined procedures (coronary artery bypass grafting and valve operation), and New York Heart Association class IV to be associated with a higher relative risk for perioperative death. Neither angina pectoris nor isolated coronary artery bypass grafting was associated with increased relative risk for perioperative death. However, after a cardiac operation, mortality in patients with end-stage renal disease was substantially higher than in those with normal renal function. CONCLUSIONS These data are comparable with those in the literature and possibly suggest that both indications and referral for surgical intervention have been delayed in patients who have end-stage renal disease combined with coronary artery disease, valve disease, or both. The delay may contribute to the relatively high perioperative mortality.

Increasing the colloid osmotic pressure of cardiopulmonary bypass prime and normothermic blood cardioplegia minimizes myocardial oedema and prevents cardiac dysfunction

UNLABELLED Our recent work demonstrated that normothermic continuous antegrade blood cardioplegia results in cardiac dysfunction related to myocardial oedema. This oedema was partially due to increased myocardial microvascular fluid filtration induced by crystalloid hemodilution. We hypothesized that increasing the colloid osmotic pressure of blood cardioplegia would stop fluid filtration into the cardiac interstitium, thus preventing myocardial oedema and cardiac dysfunction. METHODS We determined myocardial water content in six dogs by microgravimetry and myocardial lymph flow from the major prenodal cardiac lymphatic. Preload recruitable stroke work was derived from sonomicrometry and micromanometry. The dogs were subjected to normothermic cardiopulmonary bypass primed with 6% hetastarch and 1 h of normothermic continuous antegrade blood cardioplegia (4:1 blood:6% hetastarch colloid osmotic pressure 21 +/- 2 mmHg) delivered at 50 mmHg perfusion pressure. RESULTS We found that despite increased colloid osmotic pressure, a small but significant increase in myocardial water content still occurred during blood cardioplegia. As myocardial lymph flow virtually ceased during cardioplegia, myocardial microvascular filtration must have been present. However, increased myocardial lymph flow following cardioplegia resulted in complete oedema resolution associated with normal left ventricular performance post-cardiopulmonary bypass. CONCLUSIONS Our data show that the plegic myocardium is prone to oedema formation because of both relatively enhanced fluid filtration and lymph flow cessation. We conclude that increasing the colloid osmotic pressure of normothermic blood cardioplegia minimizes myocardial oedema, thus preventing post-cardiopulmonary bypass cardiac dysfunction.

Augmenting cardiac contractility hastens myocardial edema resolution after cardiopulmonary bypass and cardioplegic arrest

Although myocardial edema is associated with cardio-pulmonary bypass (CPB) and cardioplegic arrest (CPA), interventions to expedite edema removal have not been investigated. The primary mechanism for the removal of excess interstitial fluid in the heart is myocardial lymphatic drainage, but lymphatic function can be impaired by decreased contractility because of edema. The purpose of this study was to determine whether enhancing cardiac contractility would increase myocardial lymphatic function and hasten edema resolution after CPB. Sixteen dogs were subjected to CPB and 1 h of hypothermic CPA. After weaning from CPB, 10 dogs received an intravenous dobutamine infusion and 6 dogs received no inotropic support. We determined myocardial lymph driving pressure from the major cardiac lymphatic, myocardial water content by using microgravimetry, and the peak rate of left ventricular pressure increase (dP/dtmax) by using micromanometry. Measurements were taken at baseline, during CPA, and 60 min after CPB. Compared with controls, dobutamine-treated dogs had an increased dP/dtmax (P < 0.05), which was associated with higher lymph driving pressures (P < 0.05), resulting in lower myocardial water gain 1 h after CPB (P < 0.05). We conclude that the resolution of myocardial edema after CPB was hastened by dobutamine. Organized ventricular contraction and myocardial contractility seem to be important determinants of myocardial lymphatic function and myocardial edema removal. These findings suggest that the administration of inotropic drugs after CPB may hasten cardiac recovery. Implications: Myocardial edema, which develops during cardiopulmonary bypass and cardioplegic arrest, contributes to cardiac dysfunction after heart surgery. This study demonstrated that enhancement of cardiac contractility by the administration of dobutamine after cardiopulmonary bypass and cardioplegic arrest was associated with increased myocardial lymphatic function and hastened edema resolution in dogs. (Anesth Analg 1997;85:987-92)

Surgical repair of a large residual atrial septal defect after transcatheter closure

Transcatheter closure of ostium secundum atrial septal defects is a less invasive method of repairing atrial septal defects in comparison with an open heart operation. In selected patients the transvenous closure of atrial septal defects may be an effective alternative. Defects with circumferential septal rims, secundum atrial defects, and patent foramen are the best candidates for this method. We report a case in which a large residual atrial septal defect after transvenous closure with a Sideris occluder device required surgical closure.

Impact of myocardial protection during coronary bypass surgery on patient outcome

We have recently shown that continuous coronary perfusion with warm blood enriched with the ultra-short acting beta-blocker Esmolol (ES) improves functional and structural myocardial protection during coronary artery surgery as compared with conventional cardioplegia (CP). The purpose of the present study was to compare both myocardial protection techniques in terms of patient outcome. We retrospectively analyzed the charts of 150 consecutive patients subjected to coronary artery surgery using the ES-technique; 150 patients matched for age, gender, preoperative left ventricular function, history of renal failure, and history of neurological symptoms undergoing surgery with conventional CP during the same time period served as control group. There were no significant differences between both groups with respect to perioperative myocardial infarction rate, need for positive inotropic medication, need for mechanical circulatory support, duration of mechanical ventilation, duration of intensive care unit stay, time of mobilization, postoperative renal failure, cardiac arrhythmias, neurological symptoms, infections or in-hospital mortality. ES-patients were less frequently readmitted to the intensive care unit (ES: 3/150; 2.2% [95% confidence interval: 0-4.2%] vs. CP: 13/150; 8.7% [4.2-13.2%]; P=0.010) and total hospital stay was shorter (ES: 12.3+/-4.8 days [95% CI: 11.5-13.0] vs CP: 13.5+/-3.8 [12.9-14.1] days; P=0.0013), thus saving 159 patient days on the normal ward. Procedural costs were less for the ES-technique (US

Beeinflusst die Myokardprotektion während koronarer Bypassoperationen die klinischen Patientenergebnisse

60 per patient) as compared to the cardioplegia technique (US

Myocardial β-Blockade as an Alternative to Cardioplegic Arrest during Coronary Artery Surgery

120 per patient). These data suggest that myocardial protection using the ES-technique does not improve clinical outcome in patients subjected to routine coronary artery surgery, but may save costs.

Activation of myocardial constitutive nitric oxide synthase during coronary artery surgery

Zusammenfassung In Vorstudien konnten wir belegen, dass kontinuierliche antegrade Koronarperfusion mit warmen ultrakurz wirkendem Beta-Blocker (Esmolol/ES) angereichertem Blut den funktionellen und strukturellen Schutz der Herzmuskelzellen unter aortokoronaren Bypassoperation im Vergleich mit konventioneller Brettschneider-Kardioplegie (BKP) verbessert. Ziel unserer Studie war der Vergleich der beiden Protektionstechniken in Bezug auf die postoperativen klinischen Ergebnisse. Hierfür analysierten wir 150 aufeinanderfolgende Patienten retrospektiv, die mit herkömmlicher Brettschneidertechnik protektioniert worden waren und verglichen diese mit 150 Patienten, die mit kontinuierlichen warmen Blut, welches mit einem ultrakurz wirkenden Beta-Blocker angereichert war, am schlagenden Herzen mit arteriellen und venösen koronaren Bypässen versorgt worden waren. Beide Gruppen zeigten vergleichbare Werte für Alter, Geschlecht, präoperativer linksventrikulärer Funktion, präoperatives Vorhandensein von Niereninsuffizienz und neurologischen Vorschädigungen. Sie wurden im gleichen Zeitraum operiert. Es ergaben sich keine signifikanten Unterschiede zwischen den Gruppen in Bezug auf die perioperative Infarktrate, Gabe von positiv inotroper Medikation, Anwendung von kreislaufunterstützenden Systemen, Dauer der Nachbeatmung, Dauer des postoperativen Intensivstationsaufenthaltes, des Mobilisationszeitraum, Häufigkeit der postoperativer Niereninsuffizienz, Herzrhythmusstörungen, neurologischen Auffälligkeiten, Infektionshäufigkeit und 30-Tage-Mortalität. Esmolol-Patienten (ES) wurden signifikant seltener auf die Intensivstation zurückverlegt (3 von 150=2,2% [95% Konfidenzinterval: 0-4-2%] gegen 13 von 150=8,7% [KI 4,2–13,2%]; p=0,010). Außerdem wiesen ES-Patienten eine kürzere Krankenhausverweildauer auf (ES: 12,3±4,8Tage [95%-Konfidenzinterval 11,5–13,0] im Vergleich BKP-Patienten 13,5±3,8 [95%-KI 12,9–14,1] Tage; p=0,013). Damit wurden 159 Patiententage auf Normalstation gespart. Zusätzlich lagen die Kosten für die Beta-Blockade-Behandlung bei durchschnittlich 60 Euro im Vergleich zu 120 Euro für die Brettschneider-Kardioplegie-Technik pro Patient. Unsere Daten zeigten keine Unterschiede im klinischen Ergebnis zwischen den Gruppen, jedoch sehr wohl einen Unterschied in den tatsächlichen Kosten.Summary Recently it was shown that continuous coronary perfusion with warm blood enriched with the ultra-short acting β-blocker Esmolol (ES) improves functional and structural myocardial protection during coronary artery surgery as compared with conventional cardioplegia (CP). The aim of the presented study was to compare both myocardial protection techniques in terms of patient outcome. We therefore retrospectively analyzed data of 150 consecutive patients planed for coronary artery surgery using the ES-technique; 150 patients matched for age, gender, preoperative left ventricular function, history of renal failure, and history of neurological symptoms undergoing surgery with conventional CP during the same time period served as control group. There were no significant differences between both groups with respect to perioperative myocardial infarction rate, need for positive inotropic medication, need for mechanical circulatory support, duration of mechanical ventilation, duration of intensive care unit stay, time of mobilization, postoperative renal failure, cardiac arrhythmias, neurological symptoms, infections or in-hospital mortality. ES-patients were less frequently readmitted to the intensive care unit (ES: 3/150; 2.2% [95% confidence interval: 0–4.2%] vs CP: 13/150; 8.7% [4.2–13.2%]; p=0.010) and total hospital stay was shorter (ES: 12.3±4.8 days [95% CI: 11.5–13.0] vs CP: 13.5±3.8 [12.9–14.1] days; p=0.0013), thus saving 159 patient days on the normal ward. Costs of myocardial protection were less for the ES-technique (60 Euro per patient) compared to the cardioplegia technique (120 Euro per patient). These data suggest that myocardial protection using the ES-technique does not improve clinical outcome in patients subjected to routine coronary artery surgery, but may save costs.