H. Oelert

Ambulatory follow-up of aortic dissection by transesophageal two-dimensional and color-coded Doppler echocardiography.

Follow-up of 18 patients with aortic dissection (five with type I, one with type II, 11 with type III dissection according to DeBakey) by transesophageal, two-dimensional and color-coded Doppler echocardiography showed a persistence of the false lumen in five of seven patients (71%) after surgery and in nine of 11 patients (82%) after medical therapy. In two patients treated with surgery, the dissected part of the aorta had been resected, whereas in two patients treated medically, a progressive and complete obliteration of the false lumen was observed. In the false lumen, thrombus formation was absent in four, localized in four, and progressive in six patients. Flow within the false lumen could be registered in 14 patients, and two distinct flow patterns were differentiated (laminar biphasic flow or slowly circulating flow). Persisting intimal tears were visualized by two-dimensional echocardiography in four patients, whereas color-coded Doppler showed an additional one to three intimal tears in the descending aorta in 10 patients. Flow across these intimal tears was biphasic in 75% of patients; that is, systolic flow was directed from the true to the false lumen with diastolic flow reversal. Unidirectional flow was detected in 25% of the communications, directed in 20% from the true to the false lumen, serving as an entry only and in one (5%) as reentry only. Additional information concerning complications like extension of the dissection (one of 18 patients), localized dilatation of the regurgitation (three of 18 patients) were detected by this method. Concerning the morphologic findings and the detection of flow characteristics, the transesophageal approach was superior to conventional echocardiography especially in the descending thoracic aorta. Thus, transesophageal two-dimensional and color-coded Doppler echocardiography seems to be an ideal method not only for the easy detection of aortic dissection but also for follow-up.

Long-term results after thromboendarterectomy for chronic pulmonary embolism

OBJECTIVE In patients with chronic thromboembolic pulmonary hypertension, pulmonary vascular resistance (PVR) can be reduced by pulmonary thromboendarterectomy (PTE). In this study, long-term symptomatic and hemodynamic effects were investigated. METHODS Twenty-two patients (12 female, 10 male, mean age 40 years, preoperative NYHA functional class II/III/IV: n = 1/12/9) were re-evaluated 48-72 months (mean 60 months) after surgery. In addition to clinical assessment, radiologic, hemodynamic and echocardiographic investigations were performed. RESULTS All patients reported a marked improvement of their clinical condition. At follow-up, 11 patients were identified as NYHA class I, 10 as NYHA class II and one patient was in class III. PVR and mean pulmonary artery pressure (mPAP) were significantly reduced (preoperative PVR 800+/-274 dynes/s per cm(-5), follow-up PVR 180+/-28.3 dynes/s per cm(-5); P < 0.001; preoperative mPAP 48.5+/-7.4 mmHg, follow-up mPAP 27.5+/-4.9 mmHg; P < 0.001). There was also a significant increase in arterial blood oxygen tension (preoperative PaO2 59+/-10 mmHg; follow-up PaO2 84+/-12 mmHg; P < 0.001). Chest roentgenograms and echocardiographic examinations revealed significantly decreased right heart dimensions and a recovery of right heart function. CONCLUSION In patients with severe chronic thromboembolic pulmonary hypertension, persistent symptomatic and hemodynamic improvements can be achieved by PTE.

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.

Regurgitant Flow in Apparently Normal Valve Prostheses: Improved Detection and Semiquantitative Analysis by Transesophageal Two-dimensional Color-coded Doppler Echocardiography

In 128 patients with apparently normally functioning prosthetic valves (n = 136) in the aortic position (n = 79) and the mitral position (n = 57), the prevalence of transprosthetic regurgitant flow was studied by use of transthoracic and transesophageal two-dimensional color-coded Doppler echocardiography. With the transthoracic approach, regurgitant flow was detected in early systole or diastole for 28% of the mitral prostheses and for 29% of the aortic prostheses. With transesophageal color-coded Doppler echocardiography, regurgitant jets were visualized for 95% of the mitral prostheses and for 44% of the aortic prostheses. In 40% of the Björk-Shiley prostheses and 88% of the St. Jude Medical prostheses in the mitral position, more than one jet with an eccentric origin was detected, whereas in bioprostheses only one centrally localized regurgitant jet was noted. The regurgitant jet length was 22 +/- 2 mm in mitral prostheses and 12 +/- 2 mm in aortic prostheses. The jet area was 154 +/- 31 mm2 in mitral prostheses and 61 +/- 26 mm2 in aortic prostheses. Jets of this size and frequency have to be considered a normal finding and the equivalent of regurgitant flow known from in vitro studies. We conclude that only transesophageal color-coded Doppler echocardiography seems to be a reliable method for following up mitral valve prostheses to detect and differentiate regurgitant jets. For aortic valve prostheses the advantage of transesophageal color-coded Doppler echocardiography does not seem to be as obvious as the advantage for mitral prostheses.

Aktuelle Frühergebnisse nach pulmonaler Thrombendarteriektomie bei chronischer thromboembolischer pulmonaler Hypertonie

Die pulmonale Thrombendarteriektomie ist ein potentiell kuratives Operationsverfahren bei Patienten mit chronischer thromboembolischer pulmonaler Hypertonie. Von Juni 1989 bis Dezember 1994 wurden in unserer Klinik 109 Patienten einer pulmonalen Thrombendarteriektomie unterzogen. Seit Januar 1995 wurden vielfältige Veränderungen des operativen und postoperativen Therapiekonzepts vorgenommen. Wir berichten über die Frühergebnisse von 32 Thrombendarteriektomien, die von Januar 1995 bis Januar 1997 durchgeführt worden sind. Zweiunddreißig Patienten (16 Frauen und 16 Männer, Durchschnittsalter 55 J.) wurden unter extrakorporaler Zirkulation und Phasen des Kreislaufstillstands in tiefer Hypothermie operiert. Von den 32 Patienten wurden präoperativ 21 dem Stadium III und 11 dem Stadium IV der NYHA-Klassifikation zugeordnet. Der mittlere Pulmonalarteriendruck (mPAP) war auf 51 ± 11 mm Hg und der mittlere pulmonale Gefäßwiderstand auf 967 ± 238 dynes ˙ s ˙ cm-5 erhöht. Die perioperative Letalität betrug 9,3% (3/32). Die 29 überlebenden Patienten wurden im Mittel 35 Stunden (12 bis 190 Stunden) nach der Operation extubiert. Der pulmonalvaskuläre Widerstand konnte durch den Eingriff signifikant von 958 ± 248 dynes ˙ s ˙ cm-5 auf 301 ± 151 dynes ˙ s ˙ cm-5 (p < 0,001) und der mittlere Pulmonalarteriendruck von 51 ± 11 mm Hg auf 28 ± 10 mm Hg gesenkt werden (p < 0,001). Die pulmonale Thrombendarteriektomie ist das Therapieverfahren der Wahl bei chronischer thromboembolischer pulmonaler Hypertonie. Durch Modifikationen des operativen und postoperativen Konzepts und mit zunehmender Erfahrung können die Frühergebnisse des Verfahrens verbessert und eine perioperative Letalität unter 10% erreicht werden. Pulmonary thromboendarterectomy (PTE) is a potentially curative procedure in chronic thromboembolic pulmonary hypertension. From June, 1989, to December, 1994, we performed PTE in 109 consecutive patients. Multiple changes in surgical approach and postoperative management have been implemented since January, 1995. We report the early results of 32 thromboendarterectomies performed from January, 1995, to January, 1997. Thirty-two patients (16 females, 16 males; mean age 55 years) were operated using cardiopulmonary bypass, deep hypothermia and circulatory arrest. Preoperative NYHA functional class was II in 21 and IV in 11 patients. Pulmonary vascular resistance (PVR) and mean pulmonary artery pressure (mPAP) were elevated to 967 ± 238 dynes ˙ s ˙ cm-5 and 51 ± 11 mm HG respectively. The perioperative mortality rate was 9.3% (3 of 32). Twenty-nine survivors were weaned from mechanical ventilation and extubated after a mean of 35 hours (12 to 190 hours). PVR was reduced to 301 ± 151 dynes ˙ s ˙ cm-5 (p < 0.001) and mPAP was reduced to 28 ± 10 mm Hg (p < 0.001). Pulmonary thromboendarterectomy is an effective surgical procedure for chronic thromboembolic pulmonary hypertension. By means of modifications in surgical approach and postoperative management, early results can be improved and perioperative mortality can be decreased to less than 10%.

Endovascular treatment of acute bleeding complications in traumatic aortic rupture and aortobronchial fistula.

OBJECTIVE Herein we report our experience in placement of endovascular stentgrafts in the descending aorta in patients with acute bleeding complications due to traumatic rupture or aortobronchial fistula. METHODS Six patients (one woman, five men, mean age 47+/-19 years) were treated from September 1995 to February 2000 by implantation of endovascular stentgrafts in the descending aorta. Indications included traumatic ruptures of the aortic isthmus (n=3) and aortobronchial fistulas (n=3). All procedures were performed under general anaesthesia. The implants were introduced under fluoroscopic guidance via the aorta (n=1), the iliac (n=4) or femoral (n=2) artery, respectively. RESULTS All aortobronchial fistulas and ruptures were sealed up successfully. There was no perioperative morbidity and no procedure-related morbidity except one patient who received aortofemoral reconstruction because of iliac occlusive disease. All patients are alive and well after a mean follow-up of 31 months (range 6-60). Two patients had recurrent hemoptysis, in one case, the patient received a second implant (distal extension), the other patient was managed conservatively. CONCLUSION Endovascular treatment by a stentgraft is a safe and reliable procedure in the management of acute bleeding complications in patients with aortic rupture or aortobronchial fistulas.

Effects of tolazoline and prostacyclin on pulmonary hypertension in infants after cardiac surgery

OBJECTIVE To evaluate the hemodynamic effects of tolazoline and prostacyclin in infants with pulmonary vasospasm after cardiac surgery. DESIGN Prospective cohort study. SETTING Pediatric ICU. PATIENTS The cohort consisted of 42 infants and children with congenital heart disease and pulmonary hypertension who underwent corrective surgery and were monitored postoperatively using pulmonary artery catheters. Fourteen infants (2 to 12 months old) in this group required postoperative treatment with tolazoline or prostacyclin. INTERVENTIONS Tolazoline was administered as a bolus of 0.5 mg/kg for treatment of persistent pulmonary hypertension or acute pulmonary hypertensive crisis. If its effectiveness was proved after 30 mins by hemodynamic measurements, a continuous iv infusion of 0.5 mg/kg/hr was established. Higher doses of tolazoline were avoided. If tolazoline treatment did not fulfill the criteria for pulmonary vasodilation, prostacyclin was given by continuous iv infusion at a starting rate of 5 ng/kg/min, followed by 10 ng/kg/min. In three patients, the infusion rate was increased to 15 ng/kg/min. RESULTS Bolus administration of tolazoline resulted in a distinct pulmonary vasodilation in seven infants: mean pulmonary artery pressure and pulmonary vascular resistance decreased by an average of 35% and 45%, respectively. In these patients, tolazoline was infused over the following 12 to 72 hrs. One infant who received tolazoline for 72 hrs developed a clinically important gastrointestinal hemorrhage. In seven nonresponders to tolazoline, prostacyclin (PGI2) at an infusion rate of 5 ng/kg/min led to pulmonary vasodilation in five patients, at an iv infusion rate of 10 ng/kg/min in all seven infants studied. The latter dose of PGI2 reduced the mean pulmonary artery pressure by an average of 37%, and pulmonary vascular resistance by 43%. Transient withdrawal of prostacyclin in five infants demonstrated its short half-life and clinical effectiveness. Apart from a facial flush, no side-effects were encountered using PGI2 as an infusion over durations ranging from 12 to 504 hrs. CONCLUSIONS These data suggest that, if tolazoline in a relatively low dose proves to be inefficient, prostacyclin can still be used as a safe and effective drug for treatment of pulmonary vasospasm. Prostacyclin offers more than a pharmacologic alternative to increased tolazoline dosages.

Continuous monitoring of mixed venous oxygen saturation in infants after cardiac surgery

Continuous mixed venous oxygen saturation SvO2c was measured in 16 infants immediately after cardiac surgery. A polyurethane 4F, dual channel catheter (Opticath, Modell U440, Oximetrix) with fiberoptic filaments was introduced into the pulmonary artery during cardiothoracic surgery. The catheters were left in place for an average of 67.5 h (range 27 h – 125 h) and there were no catheter-related complications. Correlation between continuous in vivo SvO2 values and in vitro values was satisfactory (r=0.85), whereas a correlation between SvO2c and arterial oxygen saturation (SaO2) was not found (r=0.07). The sampled arterial lactate values were inversely correlated to the simultaneously measured SvO2c, but the corelation coefficient was only r=-0.4. There was an inverse correlation between SvO2c and arteriovenous oxygen content difference (Ca−vDO2c) (r=-0.82), and a marked inverse correlation to the calculated oxygen utilization ratio (r=-0.97). Therefore SvO2c continuously reflects the overall balance between oxygen consumption and delivery, but the use of SvO2 as a predictor of blood lactate levels is unreliable. A further purpose of the present study was to demonstrate the clinical applications and to show the usefulness of SvO2c-monitoring; particularly as a surveillance and early warning system, as a guide for assessing therapy and its relevance in interpreting other monitored parameters. In our opinion continuous SvO2 measurement is a reliable and valuable indicator of cardiopulmonary function in the immediate post-operative period, even in infants with complicated repair of cardiac malformations.

Diagnosis of perioperative myocardial necrosis following coronary artery surgery ― a reappraisal of isoenzyme analysis

Although the routine determination of CK-MB activity is widely used after coronary artery bypass grafting (CABG), the diagnosis of a perioperative myocardial necrosis remains arbitrary. The intention of the present study was to develop discriminative enzymatic parameters of CK-MB activity in a collective of 710 patients following CABG. Patients were grouped according to their postoperative electrocardiogram (ECG). For each patient, the time activity curve of CK-MB was determined. The total amount of CK-MB was calculated by integrating the area beneath the CK-MB activity curve. Patients presenting with an unchanged postoperative ECG (group I) or a new bundle branch block with uncompromised haemodynamics (group IIa) had an uniform and low profile of CK-MB activity. Serial CK-MB activities as well as the integrated CK-MB area of these two collectives were significantly different (P less than 0.001) from values determined for patients with bundle branch block and low cardiac output (group II b) or patients with new Q waves (group III). After 24h, the 90th percentile of serial CK-MB activities of group I had declined to 18 U/l and was clearly exceeded by 90% of all patients that belonged to either group IIb or III. The 90th percentile of CK-MB areas for group I showed a value of 801 U/l x h. CK-MB areas above 801 U/l x h were seen in about 50% of all patients of group IIa.(ABSTRACT TRUNCATED AT 250 WORDS)