[Improvement of perioperative hemodynamics and gas exchange by inhalation of nitric oxide in children with congenital cardiopulmonary defects]. / Verbesserung der perioperativen Hämodynamik und des Gasaustausches durch Inhalation mit Stickstoffmonoxid bei Kindern mit angeborenen kardiopulmonalen Fehlbildungen.

OBJECTIVES: In critically ill infants and children before or after surgery for congenital cardiopulmonary disease it was evaluated whether continuous NO inhalation can reduce pulmonary artery pressure (PAP) and improve arterial oxygen saturation (SaO2). METHODS: All patients (n = 24; age 1 day-6.5 years) were intubated and artificially ventilated. They had either secondary pulmonary hypertension (n = 16), acute respiratory distress syndrome (n = 3), or reduced SaO2 (n = 5) due to pulmonary hypoperfusion. NO was introduced into the afferent limb of the ventilator circuit close to the endotracheal tube, while continuously measuring the inspired NO and O2 concentrations. The initially applied concentration of NO was 20 +/- 2.0 ppm. RESULTS: The hemodynamic condition and/or oxygen saturation was significantly improved by NO in 23 patients (95%). Mean PAP declined significantly from 45 +/- 7 to 28 +/- 3.7 mm Hg, while mean systemic arterial pressure remained constant (56 +/- 2.1 vs. 58 +/- 2.5 mm Hg). This was related to a selective reduction in pulmonary vascular resistance by 48 +/- 8.5%. SaO2 increased significantly (p < 0.05) from 83 +/- 2.5% to 93 +/- 1.5% due to a decreased intrapulmonary right-to-left shunt. NO therapy was applied with a median of 6 days (range 1.5-36 days). During NO inhalation methemoglobin concentration was significantly increased (0.77 +/- 0.05% vs. 1.46 +/- 0.15%), but neither was oxygen transport capacity affected, nor was any evidence for accumulation observed. Using a model ventilatory circuit, a nitric dioxide (NO2) formation of 1.14 +/- 0.11% of the applied NO concentration was measured, i.e. approximately 0.5 ppm NO2 at 40 ppm NO. This amount of NO2 in the inspired gas is well below toxicologically relevant concentrations. CONCLUSIONS: Low-dose NO inhalation selectively reduces PAP and improves SaO2 in children with congenital cardiopulmonary disease during perioperative intensive care. It is expected that the overall hemodynamic improvement is related to a reduced afterload of the subpulmonary ventricle without changes in coronary perfusion pressure, as is often observed with other vasodilators applied intravenously. We recommend an upper dose limit of 40 ppm NO for continuous NO inhalation to avoid possible toxicologically relevant NO2 concentrations.

Intraoperative valvuloplasty in calcific aortic stenosis: a study comparing the mechanism of a novel expandable device with conventional balloon dilatation.

In selected patients with calcific aortic stenosis, balloon valvuloplasty is an intermediate alternative to surgery. The effect of balloon valvuloplasty to increase valve area, however, is limited and the restenosis rate is high during follow-up. To improve the results and reduce the complication rate, a new device for valvuloplasty of calcific aortic stenosis was developed. This system consists of three expandable prongs mounted on a freely movable catheter tip. To evaluate the efficacy of this new device, valvuloplasty was performed in 10 patients with severe aortic stenosis intraoperatively just prior to valve replacement. Comparison was made with the results of conventional balloon dilatation performed in an additional 20 patients during surgery. Using the new device, the relative orifice area increased from 10 +/- 3% before to 20 +/- 6% following intervention. However, in only one patient was a considerable increase of static valve area (greater than 15%) found. The results were comparable to the effect of conventional balloon dilatation, which led to an increase of orifice area from 12 +/- 7% to 24 +/- 10%. With both systems, the best results were achieved in patients with aortic stenosis and significant commissural fusion. In contrast, in bicuspid or tricuspid valves without fused commissures the effect of the intervention was limited. Because complete obstruction of the aortic valve does not occur during dilatation, this new device might be superior to conventional balloon dilatation. Preselection of patients according to the morphology of the valve seems mandatory to improve the success and reduce the complication rate of valvuloplasty in aortic stenosis.

Early and late results of the modified Waterston shunt with PTFE grafts for palliation of complex congenital cyanotic heart disease in neonates.

During a 12 year period from 1978 to 1989, 35 infants under 4 weeks of age underwent palliative surgery for complex congenital cyanotic heart disease with a short (1-1.5 cm) PTFE graft between the ascending aorta and the right pulmonary artery (modified Waterston shunt). Twenty-three infants had pulmonary atresia and 14 had severe pulmonary stenosis. Underlying cardiac lesions were tetralogy of Fallot (n = 11), single ventricle (n = 7), transposition complexes (n = 6), and intact ventricular septum and hypoplastic right heart syndrome (n = 13). There were 4 early deaths (10.7%) in the entire series, 2 of which were shunt related. Three of the 4 occurred during our initial experience with this shunt in 1978 and 1979. They led to the modified Waterston shunt being abandoned for 3 years in favor of other shunt procedures. Since 1983 one early death occurred in 28 infants (3.5% mortality) with no death in the latest 26 patients. All patients were followed up between 6 and 108 months. There were 4 late deaths, one of which was shunt related. We observed a significant difference in the shunt patency rate between 4 and 5 mm grafts: palliation was adequate after 2 years in 52% of the patients when a 4 mm graft was used and in 89% of the 5 mm graft group (p less than 0.005). Reshunting was necessary in 7 infants between 5 and 60 months after primary surgery. Recatheterization was performed in 17 infants for suspected shunt failure (n = 6) or diagnostic reasons (n = 11).(ABSTRACT TRUNCATED AT 250 WORDS)

[Results of emergency aortocoronary venous bypass surgery after failed percutaneous transluminal coronary angioplasty in patients with unstable angina pectoris]. / Ergebnisse der notfallmässigen aorto-koronaren Venen-Bypass-Operation nach fehlgeschlagener perkutaner transluminaler Koronarangioplastie bei Patienten mit instabiler Angina pectoris.

During a 4-year period from January 1985 to December 1988 140 patients underwent percutaneous transluminal coronary angioplasty (PTCA) of the culprit-vessel for unstable angina. Seventeen patients (12%) needed emergency aorta coronary bypass surgery (ACVB) for failed angioplasty. In 15 cases the culprit-vessel was the LAD and in 2 cases a dominant right coronary artery. Only in 2 cases a history of myocardial infarction was present. Twelve patients were in hemodynamic stable condition after arriving in the operating-room. Five patients were hemodynamic unstable, 4 of them were in cardiogenic shock. Four patients died representing an operative mortality rate of 23%. Three patients died from pump failure despite intraaortic balloon counterpulsation in 2 cases. One patient died from cerebral damage 12 day after surgery. All patients who died were in cardiogenic shock preoperatively. Two patients who survived suffered an extensive myocardial infarction. Thus including the patients who died from pump failure the perioperative infarction rate was 30%. From these results it is concluded that emergency ACVB after failed PTCA of the culprit-vessel in patients with unstable angina results in a significant higher mortality and morbidity as compared with patients who had primary surgery for unstable angina. The prognosis of patients after failed PTCA for unstable angina depends on the hemodynamic situation thereafter and becomes worse in patients with cardiogenic shock.

Repair of symptomatic aortic coarctation in the first three months of life. Early and late results after resection and end-to-end anastomosis and subclavian flap angioplasty.

During a 9 year period between January 1977 and December 1985, 98 consecutive infants under 3 months of age underwent surgical repair of symptomatic aortic coarctation. Resection and end-to-end anastomosis was performed in 73, subclavian flap angioplasty in 14, and other procedures in 11 patients. There were 20 (20.5%) early and 12 (12.5%) late deaths. No early deaths occurred in the isolated coarctation group. Associated complex cardiac malformations and age under 2 weeks at operation influenced significantly early and late outcome but not any particular surgical procedure. The survivors were followed from 6 months to 8 years and 8 months postoperatively. There were 16 (28%) re-coarctations among 56 survivors after end-to-end anastomosis requiring re-operation in 7 (12%) infants and 3 (30%) re-coarctations among 10 survivors after subclavian flap angioplasty requiring re-operation in 1 infant. After end-to-end anastomosis re-coarctation as well as re-operation rate was markedly lower when an interrupted suture line for the entire anastomosis was used as compared to the group with a continuous suture line of the posterior aortic wall (21% vs. 33% re-coarctation rate and 4% vs. 18% re-operation rate respectively). From our results it is concluded that subclavian flap angioplasty for relief of aortic coarctation in early infancy is not superior to resection and end-to-end anastomosis. In the end-to-end anastomosis group an interrupted suture line has a lower re-coarctation as well as re-operation rate as compared to a continuous suture line of the posterior aortic wall.

Relationship between the high-energy phosphate content and various left ventricular functional parameters of the normal and hypertrophied heart after global ischemia and reperfusion.

Using an isolated rat heart preparation (Langendorff perfusion, perfusion pressure 100 cm H2O) the correlation between the high-energy phosphate content and various left ventricular (lv) functional parameters of the hypertrophied heart (spontaneous hypertensive rats lv/body weight ratio 3.6 +/- 0.5 x 10(-3) was determined after normo- (30 min) and hypothermic (25 degrees C, 120 min) cardioplegic arrest and reperfusion, and compared with normal hearts (Wistar rats lv/body weight ratio 2.0 +/- 0.3 x 10(-3). St. Thomas Hospital solution was used as the cardioplegic agent. Before ischemia hypertrophied hearts had a significantly higher developed left ventricular pressure, pressure rate product and dp/dtmax, but a significantly lower ATP and total adenine nucleotide content. Irrespective of the mode and temperature of cardiac arrest there was a strong correlation both for normal and for hypertrophied hearts between the high-energy phosphate content expressed as ATP, total adenine nucleotides or the "energy charge" and the left ventricular functional parameters pressure rate product and dp/dtmax. The correlation coefficient ranged from 0.80 to 0.89 and was highest when the ATP content was plotted against pressure rate product (r = 0.89). There was a different slope for normal and hypertrophied hearts with a steeper decline of the left ventricular function in hypertrophied hearts for any given reduction of the myocardial adenine nucleotide content. Our results indicate that a similar reduction of the ATP or total adenine nucleotide content in both the normal and hypertrophied heart reduces left ventricular function to a greater degree in the hypertrophied heart.

[Percutaneous transluminal coronary angioplasty and aortocoronary bypass surgery in unstable angina pectoris and coronary multivessel disease]. / Perkutane transluminale koronare Angioplastie und aorto-koronare Bypass-Operation bei instabiler Angina pectoris und koronarer Mehrgefässerkrankung.

In 113 patients demonstrating the clinical syndrome of unstable angina, acute-stage coronary angiography revealed multivessel disease. Acute PTCA of the ischaemia-related coronary artery or bypass grafting was performed depending on angiographic criteria. Of the total of 68 patients in whom PTCA was performed, 45 had two-vessel disease (2 vd) and 23 three-vessel disease (3 vd). 12 of the 45 patients with bypass operation had a left main stem stenosis, whereas 33 had three-vessel disease. The primary success rate of PTCA was 81%, 89% in patients with 2 vd and 70% in patients with 3 vd. Acute post-PTCA bypass grafting was necessary in 2 patients having 2 vd and in 5 patients suffering from 3 vd. 5 of the 68 patients treated with PTCA developed a transmural myocardial infarct and one patient died after PTCA and emergency bypass surgery. 8 of the 45 operated patients had a perioperative or postoperative myocardial infarct and 5 patients died intraoperatively or postoperatively. The overall morbidity was 11.5%, and the mortality of hospitalised patients was 5.3% (6/113). Combination of PTCA with emergency bypass grafting offers a new and effective treatment with an acceptable risk even in multivessel disease patients and in those having unstable angina pectoris. The additional use of PTCA definitely improves therapeutic management in this high-risk population.

Relationship between the myofibrillar ATPase activity of human biopsy material and hemodynamic parameters.

The myofibrillar ATPase activity and pyrophosphate gel electrophoretic pattern of native myosin of fresh human left ventricular papillary muscles were examined in 52 cases of mitral valve replacement. The myofibrillar ATPase activity of hypertrophied myocardium did not differ from that of non-hypertrophied myocardium (mean +/- SD, 36.2 +/- 8.7 vs 31.8 +/- 8.6 nmolPi/mg/min, ns) and there was no significant difference in myofibrillar ATPase activity as a function of left ventricular enddiastolic pressure. Pyrophosphate gel electrophoresis of myosin revealed the presence of two components. It is questionable whether the component of higher electrophoretic mobility (approximately 25-35% in concentration) is identical with rat ventricular myosin VM-1 because an increase in this component seems to correlate with a decrease of myofibrillar ATPase activity, its concentration was significantly higher in the hearts with left ventricular hypertrophy, high enddiastolic pressure, high aortic pressure or low cardiac index. From these results, it is not necessarily clear whether hemodynamic overload in valvular heart diseases can alter left ventricular myofibrillar ATPase activity, but it can be said that the overload influences the concentration of the two components of native myosin revealed by pyrophosphate gel electrophoresis.

Ultrastructural and biochemical changes of human papillary heart muscle during different methods of induced cardiac arrest.

To determine the protective effects of different methods of cardioplegia, studies on ATP/lactate levels and ultrastructure were performed in human papillary muscles obtained during mitral valve replacement. In group I (n = 5), plain ischemic arrest in hypothermia (systemic venous temperature = 24 degrees C) was accomplished. In group II (n =12), the heart was arrested by injection cardioplegia using magnesium-aspartate-procaine at systemic venous and myocardial temperatures of 24 degrees C. In group III (n = 12) Bretschneider infusion cardioplegia at systemic venous and myocardial temperatures of 26 degrees C and 19 degrees C respectively was applied. With regard to ultrastructural changes there were no clearcut differences in the three methods of hypothermic cardiac arrest after 60 minutes of ischemia. Ischemic changes tended to be slightest in group III (infusion cardioplegia). ATP decay and lactate increase were significant in group I and moderate to minimal in groups II and III after the same period of time. It is concluded that for aortic cross-clamp times up to 60 minutes, body hypothermia and injection cardioplegia using magnesium-aspartate-procaine at a myocardial temperature of 24 degrees C provide adequate protection of the myocardium. For ischemia times beyond 70 minutes, profound myocardial hypothermia below 20 degrees C is preferred.

Clinical comparison between membrane and bubble oxygenators in cardiopulmonary bypass.

The clinical course of two similar patient groups was compared in whom, during cardiopulmonary bypass, a membrane or bubble oxygenator was employed. According to our results there is no significant functional difference between the two types of oxygenators as long as the perfusion time does not exceed 90 minutes. Beyond this time limit, the membrane oxygenator has distinct advantages, particularly with regard to hemolysis. We presently prefer the bubble oxygenator. The use of a membrane oxygenator is restricted to complex open heart procedures with suspected technical problems.

[Behaviour of ATP and lactate in human papillary muscle during profound hypothermia and injection cardioplegia with magnesium-asparatate-procaine (author's transl)]. / ATP- und Laktatgehalt des menschlichen Papillarmuskels bei tiefer Körperhypothermie und Injektionskardioplegie mit Magnesium-Aspartat-Procain.

In 53 patients with mitral- or aortic-mitral valve disease, the content of ATP and lactate of the papillary muscles resected at the time of valve replacement was investigated at the beginning of ischemic arrest and at the time of reperfusion. Profound body hypothermia (25 degrees C) and injection cardioplegia using magnesium-aspartate-procaine were applied for myocardial protection. In hypertrophic papillary muscles the myocardial ATP content decreased at a slower rate (ATP decay 12% of the initial value after 60 minutes of ischemia) than in normal papillary muscles obtained from patients with isolated mitral stenosis (ATP decay 33% of the initial value after 40 minutes of ischemia). 20% of the patients required temporary inotropic circulatory support postoperatively for 12 to 88 hours. The ATP content of the papillary muscles of these patients differed only little from those, in who no myocardial failure occurred. However the myocardial lactate levels were higher in patients in whom a low cardiac output state evolved.

[Monitoring myocardial performance after open heart surgery by calculation of diastolic and systolic pressure time index (author's transl)]. / Uberwachung der Myokardfunktion nach offenen Herzoperationen durch Messung des diastolischen und systolischen Druck-Zeit-Index.

In order to determine the incidence of subendocardial ischemia after open heart surgery, subendocardial blood flow was monitored in 171 patients subjected to mitral and/or aortic valve replacement or coronary revascularization by on-line calculation of Diastolic (DPTI) and Systolic Pressure Time Index (TTI). Body hypothermia with an esophageal temperature of 25 degrees C and magnesium-aspartate-procaine cardioplegia were applied for myocardial protection. Ten patients developed low cardiac output state with two early deaths. In the two patients with fatal low cardiac output DPTI/TTI remained below 0.8. In the remaining 8 patients DPTI/TTI rose to 1.4 after a mean recovery time of 36 hours. In 161 patients (94%) no low cardiac output state evolved and DPTI/TTI rose to 1.3 within 60 min. after termination of cardiopulmonary bypass. Our results indicate that body hypothermia of 25 degrees C combined with magnesium-aspartate-procaine cardioplegia can reduce the incidence of subendocardial ischemia, but does not prevent this complication completely after anoxic times beyond 60-70 minutes.

Estimation of adequate subendocardial blood flow by online computation of systolic pressure time index and diastolic pressure time index after cardiopulmonary bypass.

Subendocardial perfusion was monitored in 48 patients subjected to valve replacement by calculation of diastolic pressure time index (DPTI), systolic pressure time index (TTI) and DPTI/TTI. An on-line computer which derives these values from the systemic pressure and wave-form was applied. For myocardial protection general body hypothermia (esophageal temperature 25 degrees C) and hypothermic injection cardioplegia were employed. No low cardiac output state occurred and no inotropic drugs were required. In all patients DPTI/TTI rose above 1 within 60 minutes from termination of cardiopulmonary bypass so that the necessity to intraaortic balloon counterpulsation could be denied in all cases. We believe that the calculation of DPTI/TTI after extracorporeal circulation is a useful modality to predict the adequacy of subendocardial perfusion and monitor myocardial performance.

[The protective effect of magnesium-aspartate-procaine cardioplegia on the hypertrophied left ventricle of the mini-pig (author's transl)]. / Uber die protektive Wirkung der Magnesium-Aspartat-Procain-Kardioplegie auf den hypertrophierten linken Ventrikel des Mini-Pigs.

After induction of left ventricular hypertrophy by supravalvar constriction of the ascending aorta in mini pigs (ATP and lactate) were measured under different cardioplegic conditions. In normothermia and plain anoxic arrest ATP decrease and lactate increase were significantly slower in hypertrophied myocardium compared to normal myocardium. Injection cardioplegia using magnesium-aspartate-procaine at 37 degrees C did not influence the ATP decrease and lactate increase in the hypertrophied ventricle, whereas in the normal heart it showed some protection according to these parameters. Optimal ATP preservation and the lowest lactate increase rate were achieved in left ventricular hypertrophy by combined application of magnesium-aspartate-procaine and hypothermia of 25 degrees C. We conclude that normothermic injection cardioplegia has no protective effect on the hypertrophied left ventricle, whereas additional hypothermia can improve magnesium-aspartate-procaine cardioplegia significantly.

Combined application of metabolic myocardial arrest and general profound hypothermia in aortic valve replacement.

To determine the value of general hypothermia in combination with magnesium-aspartate-procaine induced metabolic myocardial arrest, the surgical results of 2 similar groups of patients subjected to aortic valve replacement were compared. Metabolic arrest of the myocardium was achieved under mild hypothermic conditions in group I (71 patients) and in profound hypothermia in group II (48 patients). The operative mortality was 5.6% in group I and 4.1% in group II. There was no cardiac related with in group II. In group I two deaths were due to a low cardiac output state. In addition, 3 patients required inotropic support during the early postoperative period. Our results indicate, that magnesium-aspartate-procaine induced cardioplegia in combination with general profound hypothermia can provide effective myocardial protection during aortic valve replacement.