Franz Xaver Schmid

Mid-term results of pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension

BACKGROUND In patients with chronic thromboembolic pulmonary hypertension, acute and striking decreases of pulmonary artery pressures and vascular resistance can be achieved by pulmonary thromboendarterectomy. In this study, the long-term effects of pulmonary thromboendarterectomy on hemodynamic indices and right ventricular function were investigated. METHODS Sixty-five patients (31 women and 34 men; mean age, 47 +/- 17 years; range, 19 to 69 years; New York Heart Association [NYHA] functional class II, n = 3; class III, n = 38; class IV, n = 24) were reassessed 13 to 48 months (mean, 27 months) after pulmonary thromboendarterectomy. Measurements are reported as mean +/- standard deviation. RESULTS All patients reported a significant improvement of symptoms: 46 patients were in NYHA functional class I, 16 patients in class II, and 3 patients in class III. Mean pulmonary vascular resistance was significantly reduced compared with preoperative and postoperative values (preoperative: 1,015 +/- 454 dynes.s.cm-5; postoperative: 322 +/- 154 dynes.s.cm-5; follow-up: 198 +/- 72 dynes.s.cm-5; p < 0.001 versus preoperative; p < 0.025 versus postoperative). Concomitantly, cardiac index was significantly increased compared with preoperative values (preoperative: 2.0 +/- 0.7 L.min-1.m-2; follow-up: 2.9 +/- 0.5 L.min-1.m-2; p < 0.001). Significant reductions of right ventricular dimensions and recovery of right ventricular function could be demonstrated radiologically and echocardiographically. In 3 patients (preoperative NYHA class IV, NYHA class III at follow-up) with proven coagulation abnormalities, pulmonary vascular resistance was moderately increased at follow-up compared with postoperative measurements. CONCLUSIONS In patients with chronic thromboembolic pulmonary hypertension, a persistent decrease of pulmonary vascular resistance and improvement of right ventricular function and NYHA functional status can be achieved by pulmonary thromboendarterectomy.

Troponin T: a reliable marker of perioperative myocardial infarction?

Following cardiac surgery, electrocardiography and creatine kinase isoenzyme MB (CK-MB) activities are of limited value in diagnosing a non-transmural infarction. With the recent availability of an assay to detect serial levels of the specific cardiocyte contractile protein troponin T the possibility has been increased of closing a diagnostic gap among cardiosurgical patients. Ninety patients with severe diffuse three-vessel disease undergoing myocardial revascularization were grouped by their postoperative electrocardiographic (ECG) findings (group I--unchanged ECG; group II--new Q-waves representing perioperative myocardial infarction (PMI)). Serial levels of troponin T and the activity of CK-MB were measured 6, 12, 24 and 48 h after aortic unclamping. The course of CK-MB activity was compared to a profile and values derived from patients with unchanged (n = 1312) or new Q-wave ECGS (n = 89). In 72 patients (80.0%) with unchanged postoperative ECG (group I) serial troponin T levels remained constantly low and reached a median peak value of 0.37 microgram/l (quartile 0.13-0.50 microgram/l) after 24 h. Serial CK-MB activities demonstrated the typical non-ischemic course with a monoexponential decline from an initial median peak value of 15.5 U/l (quartile 12.0-21.0 U/l) to 7.0 U/l (quartile 6.0-9.0 U/l). In seven patients (7.8%) with new Q-waves and a pathologic CK-MB profile (group II) troponin T reached median levels of 10.47 micrograms/l (quartile 6.34-12.50 micrograms/l) (P < 0.001 I vs II). Four of five patients with a new right bundle branch block demonstrated low troponin T levels below 1 microgram/l and a normal CK-MB profile. Among six patients with unchanged QRS-configuration and elevated troponin T levels between 0.84 and 4.99 micrograms/l CK-MB activity showed a characteristic PMI pattern in two patients. Troponin T is characterized by a very narrow margin of normal values represented by a maximum third quartile of 0.50 microgram/l. A singular value of troponin after 6 h or 24 h may be sufficient evidence to confirm the diagnosis of a PMI.

Reduced inotropic support after aprotinin therapy during pediatric cardiac operations

BACKGROUND Several reports indicate that aprotinin treatment before and during cardiopulmonary bypass (CPB) might have a protective effect on the myocardium. We evaluated the hemodynamic effects of perioperative aprotinin treatment. METHODS We conducted a randomized, double-blind, placebo-controlled trial in 34 infants (mean age, 2.5 years) who had cardiac operations. Half of the patients received high-dose aprotinin therapy. There were no significant differences between the aprotinin and placebo groups with respect to age, weight, sex, aortic cross-clamp time, and CPB time. The following data were recorded at arrival in the intensive care unit 6, 12, 24, and 48 hours after termination of CPB: heart rate, blood pressure, left atrial pressure, central-peripheral temperature difference, arterial-central venous oxygen saturation difference, urine output, serum creatinine, lactate and neutrophil elastase levels, the Doppler echocardiographic factors shortening fraction and preejection period/left-ventricular ejection time, and cumulative doses of catecholamines (epinephrine), enoximone, and furosemide. RESULTS No hemodynamic variable showed any significant difference between aprotinin and placebo groups. Urine output, creatinine, lactate, and elastase levels, as well as the cumulative doses of furosemide and epinephrine were not significantly different. Twelve hours after CPB 10 patients in the placebo group and 4 in the aprotinin group had received enoximone (p<0.05). The placebo group had received significantly larger doses of enoximone than the aprotinin group at arrival in the intensive care unit (0.13+/-0.05 versus 0 mg/kg), 12 hours after CPB (0.58+/-0.14 versus 0.18+/-0.09 mg/kg), 24 hours after CPB (1.11+/-0.24 versus 0.42+/-0.16 mg/kg), and 48 hours after CPB (1.61+/-0.40 versus 0.86+/-0.28). At 6 hours the difference did not reach statistical significance. CONCLUSIONS Clinical and hemodynamic status of the aprotinin-treated patients was similar to that of the placebo-treated patients in the first 48 hours after CPB. The placebo group, however, required significantly more inotropic support by enoximone than the aprotinin group to achieve this goal.

Adjustable tourniquet to manipulate pulmonary blood flow after Norwood operations

BACKGROUND Survival after first-stage palliative Norwood operations for single ventricle with systemic outflow obstruction is mainly dependent on a balanced ratio of pulmonary blood flow to systemic blood flow. Here we report the clinical results using a modified technique that allows a controlled systemic-to-pulmonary shunt flow to prevent pulmonary overcirculation. METHODS From 1995 to 1998, of 26 infants undergoing first-stage palliative Norwood operations, 7 had placement of an adjustable tourniquet around a modified right Blalock-Taussig shunt. RESULTS Hospital survival was 20 of 26 patients (77%). All 7 patients in whom snaring of the shunt was indicated survived. Two patients underwent repeated adjustment, in 5 patients the tourniquet could be removed during delayed sternal closure, and 2 patients were discharged with the shunt partially snared. CONCLUSIONS The snare-controlled systemic-to-pulmonary shunt allows improved hemodynamic stability after reconstructive surgery for hypoplastic left heart syndrome or other similar complex cardiac defects by reducing the risk of pulmonary overcirculation. It is simple and rapidly executed. The option of graded banding of the shunt depending on the hemodynamic situation increases flexibility and safety after cardiopulmonary bypass or at any time in the postoperative period.

Evaluation of gastric intramucosal pH during and after pediatric cardiac surgery

OBJECTIVES In adult patients, intramucosal pH (pHi) has been advocated to detect postoperative complications. The purpose of our study was to evaluate this technique in pediatric patients during and after cardiac surgery. METHODS Thirty-five infants (age: 5 days to 15 years, median 1.8 years; and weight: 3.2-32 kg, median 9.8 kg) were studied. pHi was measured before cardiopulmonary bypass (CPB), after 30 min of CPB, prior to weaning off CPB, at intensive care unit arrival, and 6, 12, 24, 48 and 72 h after surgery. RESULTS There were no complications related to the tonometer. A pathologically low pHi < 7.32 was found during surgery in less than 17%, at intensive care unit arrival in 83% and after 48 h in 18%. pHi values were lower (P < 0.05) at intensive care unit arrival (7.25 +/- 0.08) and after 6 h (7.28 +/- 0.09) than afterwards. pHi correlated with arterial pH (r = 0.66), central-peripheral temperature difference (r = -0.36), lactate (r = -0.32) and central venous pressure (r = -0.21). Patients after a Fontan procedure had postoperatively a lower pHi than after other operations (P < 0.05). None of the patients died or developed organ failure. Six patients had signs of organ dysfunction. Their pHi (median 7.23, range 7.14-7.28) could not differentiate them from the other patients. CONCLUSIONS With current equipment, tonometry cannot be recommended for the management of pediatric patients after cardiac surgery. However, as a semi-invasive method tonometry deserves further evaluation.

Cardiac pacing in premature infants and neonates: steroid eluting leads and automatic output adaptation.

BACKGROUND Appropriate generator and lead selection as well as techniques of implantation are most important aspects of cardiac pacing in the extremely young patient. Here we report the clinical results using a new technique with automatic output adaptation based on evoked response in combination with steroid-eluting epicardial leads in small children. METHODS One neonate and 2 premature infants underwent permanent pacemaker implantation because of congenital high-degree atrioventricular block or postoperative complete heart block, respectively. Steroid-eluting epicardial leads and a multiprogrammable pacemaker with automatic output adaptation were used. RESULTS Intermuscular abdominal generator placement and epicardial suture-fixation of the bipolar lead through a subcostal approach was without complications. Serial follow-up examinations revealed safe and consistent pacemaker function up to 12 months after operation. CONCLUSIONS The technique represents an excellent alternative for permanent cardiac pacing in extremely small patients. We believe that it provides an increase in functional lifetime of the devices and delays the need for battery replacement with its associated complications in this young patient population.

Influence of incremental preoperative risk factors on the perioperative outcome of patients undergoing emergency versus urgent coronary artery bypass grafting.

A retrospective analysis of 127 patients with impending myocardial infarction undergoing coronary artery bypass grafting was performed to evaluate incremental risk factors associated with perioperative mortality and morbidity. Fifty-four patients (group 1) were operated upon as emergencies within 24 h and 73 patients underwent urgent coronary revascularization within a mean of 3.4 days (group II) after admission. The incidence of non-transmural myocardial infarctions (NTMI), haemodynamic parameters, the number of diseased vessels and the incidence of a preceding percutaneous coronary dilatation (PTCA) were not statistically different between the groups. The overall perioperative mortality was 8.7% (16.7% group I, 2.7% group II). Major non-fatal complications were frequent in the surviving collective including low cardiac output in 14 patients (12.1%) and transmural or subendocardial perioperative infarction in 12 patients (10.3%). Perioperative mortality was associated with reduced left ventricular myocardial function (P less than 0.001), operation within 24 hr after onset of anginal symptoms (P less than 0.001) or subendocardial infarction (P less than 0.025) in the 4 weeks before operation. Perioperative mortality was independent of the degree of coronary stenosis, number of distal anastomoses or performance of a coronary endarterectomy. Of the patients, 90.5% (87.5% of group I and 92.3% of group II) included in a mean follow-up of 16.8 months (range 5-27 months) were graded into Canadian Heart Functional Class I. Successful coronary surgery for acute myocardial ischaemia results in excellent late functional recovery. The major risk factors for fatal perioperative outcome are reduced left ventricular function and the necessity of every early surgical intervention.

The Fontan-Operation: From Intra- to Extracardiac Procedure

PURPOSE For treatment of univentricular heart, the Fontan operation has been established as the definitive palliation. The current controversy is mainly based on the high incidence of arrhythmias after an intra-atrial lateral tunnel Fontan operation. METHODS From January 1995 until April 2002, 46 children underwent a Fontan-type operation with or without a small fenestration. In 33 patients (group I) an intracardiac tunnel and in 13 patients (group II) an extracardiac conduit procedure was performed. PRINCIPAL FINDINGS There was no perioperative mortality. All patients showed postoperative a significant increase of arterial oxygen saturation, from 76 to 86% after surgery with fenestration, or to 90.5% without fenestration respectively. In patients with fenestration procedure, the saturation rose to 90% after closure of fenestrations 9 to 12 months after operation. CONCLUSIONS Modified Fontan operations can be performed in normothermia on the beating heart with acceptable mortality. The extracardiac conduit Fontan procedure has the benefits of less surgical injury and a higher intraoperative flexibility.

Immune Response to Gelatin- and Collagen-Impregnated Aortic Dacron Grafts A Randomized Study

Dacron grafts are very common in vascular surgery. Primarily sealed grafts have been available for ten years. These improve handling and reduce intraoperative blood loss. Despite a widespread use all over the world, it has as yet not been clarified whether coating (sealing) substances might cause an immune response, especially in situations of fever or other unexplained events in the postoperative course after graft implantation. In this study, 37 patients with a gelatin-impregnated (Unigraft) and 33 with a collagen-impregnated (Hemashield) graft for aortic or aortoiliac replacement were compared. Serum samples were investigated for collagen antibodies at operation, one week and three months postoperatively. An enzyme-linked immunosorbent assay (ELISA) test could not demonstrate the development of antibodies against type I, II, or III collagen in the perioperative period or three months postoperatively.

Revaskularisation mit der A. gastroepiploica dextra — Bewertung der Indikation und des perioperativen Risikos

ZusammenfassungBei 35 Patienten (mittleres Alter 64,0 Jahre (±10,4 Jahre) wurde bei fehlender oder unbrauchbarer V. saphena magna neben der einoder beidseitigen A. thoracica interna (ITA) die rechte A. gastroepiploica (GEA) zur Revaskularisation der rechten Koronararterie (RCA) verwendet. Ausgeschlossen wurden Patienten mit erheblicher Adipositas (Broca-Index >20%) sowie Patienten mit abdominellen Voroperationen. In einem Fall konnte die GEA wegen Plaquebildung nicht verwendet werden. Bei 23 Patienten wurde die GEA mit dem R. interventricularis posterior (RIVP), bei 11 Patienten mit der RCA vor bzw. in Höhe der Crux anastomosiert.Von den 34 mit GEA versorgten Patienten verstarb einer (2,9%), bei dem die GEA mit einer dominanten RCA anatomososiert war, frühpostoperativ an therapierefraktärem Herzversagen. Bei diesem Patienten wurde die während der Reanimation von der Anastomose abgescherte GEA frei blutend in der Bauchhöhle gefunden. An weiteren Komplikationen trat bei einem Patienten ein konservativ beherrschbarer paralytischer Ileus auf. Eine Kontroll-DSA bei 24 Patienten zeigte bis auf einen funktionellen Verschluß eine freie Durchgängigkeit der GEA mit Darstellung der Anastomose.Die GEA bietet die Möglichkeit, den mit der rechten ITA nur eingeschränkt erreichbaren Teil der distalen RCA zu versorgen. Aufgrund des möglicherweise initial relativ geringen Flusses der GEA stellt eine stenosierte und dominante RCA primär dagegen eine Indikation zum Venenbypass dar.SummaryIn 35 patients (mean age 64.0 years (±10.4 years) with an inadequate greater saphenous vein the right gastroepiploic artery (RGEA) was used together with the uni- or bilateral internal thoracic artery (ITA). Patients with extreme obesity (Broca-Index >20%) as well as patients with previous abdominal operations were excluded. In one case the GEA had to be discarded because of plaque formation. The GEA was anastomosed with the posterior descending artery in 23 patients and directly with the right coronary artery (RCA) in 11 patients.One patient (2.9%) in whom the GEA had been anastomosed with a dominant RCA died perioperatively because of refractory myocardial failure. During the reexploration the GEA was found sheared off within the abdominal cavity. One patient suffered from a paralytic ileus that was treated without operation. Digital intraarterial subtraction angiography revealed a patent GEA in 24 patients and one functionally occluded bypass in one.The right gastroepiploic artery offers the possibility to supply the distal part of the right coronary artery that is difficult to reach with the right ITA. In case of a stenotic and dominant RCA venous bypass should be preferred because of a possible initial low flow of the GEA.