Endovascular surgery--the state of the art.
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Humans↗
Biomedical subjects
R Moosdorf
Publications and source records attributed to R Moosdorf.
Failure of an implantable cardioverter-defibrillator to redetect ventricular fibrillation in patients with a nonthoracotomy lead system.
BACKGROUND: Shock delivery of an implantable defibrillator may cause a change in the amplitude of endocardial electrograms and impair the detection of ventricular fibrillation. Thus, the effects of shock discharges on the amplitude of endocardial electrograms were evaluated in five patients undergoing implantation of a cardioverter-defibrillator in combination with a new nonthoracotomy lead system. METHODS AND RESULTS: At implant, bipolar endocardial electrograms were recorded before each shock application, during ventricular fibrillation, during redetection of ventricular fibrillation in case the applied shock was ineffective, and at intervals of 5, 10, 20, 30, 60, and 120 seconds after each shock delivery. The amplitude of the endocardial electrograms decreased from 10.5 +/- 3.8 mV during sinus rhythm to 6.3 +/- 1.9 mV during initial ventricular fibrillation and declined to 2.2 +/- 1.3 mV during redetection of ventricular fibrillation. After successful termination, the following bipolar electrograms could be obtained at the predetermined intervals: 1.9 +/- 1.2 mV, 3.1 +/- 1.8 mV, 4.5 +/- 1.9 mV, 6.5 +/- 2.9 mV, 9.5 +/- 3.3 mV, and 10.4 +/- 3.8 mV. At predischarge testing, failure of redetection of ventricular fibrillation could be documented in two patients, requiring rescue external defibrillation in both cases to restore sinus rhythm. CONCLUSIONS: These findings demonstrate that the implantable cardioverter-defibrillator did not ensure reliable redetection of ventricular fibrillation in patients using the implanted nonthoracotomy lead system. Thus, the potential risk of sudden cardiac death may persist in these patients despite defibrillator therapy.
Cardiomyopathy, Dilated↗
Pediatric heart transplantation for congenital heart disease and cardiomyopathy.
Orthotopic heart transplantation has become an accepted therapy for adult patients with end-stage heart disease. In newborns and infants, this procedure is still controversial because of the unknown long-term results and the lack of donor organs. Since March 1988, we have performed orthotopic heart transplantation in 11 infants and children with hypoplastic left heart syndrome (n = 6), cardiomyopathy (n = 4), or congenital endocardial fibroelastosis (n = 1). The smallest infant was 3 days old and weighed 2,650 g. Four of 15 potential donors had to be refused for various medical reasons, and 4 were transferred to our hospital for organ retrieval. Seven hearts were procured remotely. We accepted weight mismatches up to 105% between donor and recipient. There were three perioperative deaths, two in patients 5 and 17 days old with hypoplastic left heart syndrome and 1 in a 2-year-old patient with a dilated cardiomyopathy. All 3 patients had drug-resistant right heart failure. A 2-year-old girl with a dilated cardiomyopathy died 2 months after transplantation owing to severe pulmonary embolism originating from the superior vena cava. The remaining 7 patients are alive and well between 1 month and 31 months after transplantation. Angiographic follow-up has not revealed signs of graft atherosclerosis at 2 years.
Cardiomyopathy, Dilated↗
The role of pericardiectomy in pericardial disorders.
Pericardiectomy today is an accepted therapeutic concept in patients with different pericardial disorders. The postoperative outcome of patients is mainly influenced by two factors. First, diagnosis has to be established early to avoid myocardial deterioration and secondary organ failure, especially of liver and kidneys. Second, the whole accessible surface of atria and ventricles has to be freed from diseased and calcified pericardium. To achieve this, we prefer a total median sternotomy for the surgical approach. In selected cases of acute pericardial effusion or as a palliative procedure, a small infrasternal incision or anterolateral thoracotomy is used for pericardiocentesis and creation of a pericardio-pulmonary window. Between January 1969 and March 1990 we treated 187 patients with different pericardial disorders. Mortality was 4.8% overall, and was especially low (2.8%) among the 106 patients with acute and chronic pericardial effusion. Out of 67 patients with constrictive pericarditis, four died during hospital stay (5.9%). The prognosis is still poor for patients with primary or secondary malignant pericardial tumours, in whom surgery is mostly restricted to palliative resection, and a special group with constrictive and mostly calcified epicarditis, for whom no surgical option is available.
Cardiac Tamponade↗
Enoximone treatment of impaired myocardial function during cardiac surgery: combined effects with epinephrine.
Enoximone belongs to a new class of noncatecholamine-positive inotropes, which selectively inhibit phosphodiesterase type III and increase cyclic AMP (cAMP). This study was performed in 30 coronary artery surgery patients with impaired myocardial function (ejection fraction [EF] less than 50%). The study's two purposes were to investigate the hemodynamic effects of enoximone, 0.5 mg/kg, administered following induction of anesthesia (phase I), and to assess whether enoximone can potentiate the actions of sympathomimetic agents during weaning from cardiopulmonary bypass (CPB) (phase II). Starting with already reduced hemodynamics, induction of anesthesia led to a further deterioration of blood pressure and cardiac output (CO). Administration of enoximone produced a significant increase in cardiac index (CI) (+47%), whereas pulmonary capillary wedge pressure (PCWP) (-37%), pulmonary artery pressure (PAP) (-17%), and systemic vascular resistance (SVR) (-17%) were significantly reduced. Heart rate (HR) was not increased, and no dysrhythmias occurred during the investigation. The hemodynamic effects were maintained for 30 minutes until the start of the operation. In phase II, where weaning from CPB was not possible without pharmacological support, either enoximone (0.5 mg/kg) + epinephrine (0.1 micrograms/kg/min) or only epinephrine (same dosage) was randomly selected. Weaning was successful in both groups, but the combined therapy produced a larger increase in cl and a more pronounced decrease of the elevated filling pressure (PCWP). PAP was not changed in the combined therapy group, but increased in the patients receiving epinephrine alone. It is concluded that enoximone has beneficial hemodynamic effects in the perioperative period, and that potentiation of the effects of epinephrine in severe heart failure may be one of the drug's most useful features.
Aged↗
Tumors of the heart. Experiences at the Giessen University Clinic.
Of 54 cardiac tumors operated upon in our clinic, 42 were classified as benign and only 12 as malignant. The major part of the benign tumors were myxoma, mainly located in the left atrium. While smaller tumors could be treated by local resections, extensive resections were necessary in 14 patients with greater tumors followed by reconstructions of the pulmonary and caval vein, mitral and tricuspid valve, and major parts of the right and left ventricular wall. In one patient with a huge benign myxoma, tumor exposition and total resection could only be achieved by an autotransplantation of the heart. While mortality after surgical therapy of benign tumors was only 1.4% (1/42) within a mean follow-up time of 48 months, the prognosis of malignant tumors is still fatal with a mortality of 50% (6/12) within a mean follow-up time of 24 months, despite additional chemotherapy or radiation.
Germany, West↗
Preoperative plasmapheresis in patients undergoing cardiac surgery procedures.
Donor plasmapheresis that is carried out weeks before the operation has proven to be of benefit in elective orthopedic patients with regard to reducing homologous blood consumption and preserving coagulation. In this study acute preoperatively performed plasmapheresis (APP) was investigated in cardiac surgery patients. Forty-five patients scheduled for elective aortocoronary bypass surgery were randomly divided into three groups of 15 patients each: 1) removal of platelet-poor plasma (PPP), 2) removal of platelet-rich plasma (PRP), and 3) no plasmapheresis (control group). Plasma volume removed was 10 ml/kg in all APP patients, and plasma was replaced by the same amount of low-molecular weight hydroxyethylstarch solution (6% HES 200/0.5). Various laboratory data were investigated before, during, and after extracorporeal circulation (ECC). Blood loss in control patients was more pronounced than in the two APP groups; two of the control patients needed packed red cells. APP itself did not affect coagulation variables, free hemoglobin, or polymorphonuclear (PMN) elastase. At the end of the operation, 5 h after ECC, and at the first postoperative day the number of platelets was significantly lower in the control group; PRP patients showed the highest values. Fibrinogen and AT-III levels were less compromised in APP patients than in the control group. Global coagulation parameters did not differ between the groups within the whole investigation period. PMN elastase increased significantly during ECC in all groups with the greatest increase in the control group (722%) and the smallest increase in PRP patients (280%), possibly due to the removal of cellular elements in this group.(ABSTRACT TRUNCATED AT 250 WORDS)
Aged↗
Cardiac transplantation in a neonate with endocardial fibroelastosis.
An investigational orthotopic cardiac transplantation was performed to manage subendocardial fibroelastosis in a neonate. No unmanageable technical complications arose from the transplantation. Postoperative observation showed the infant developed normally except for moderate cerebral palsy.
Journal Article↗
Influence of acute volume loading on right ventricular function after cardiopulmonary bypass.
The influence of acute volume loading on right ventricular function immediately after extracorporeal circulation (ECC) was investigated in 25 patients undergoing elective aortocoronary bypass grafting. In addition to commonly monitored hemodynamic variables, right ventricular (RV) ejection fraction (EF) was measured by thermodilution technique using a new fast-response thermodilution catheter. In eight patients with concomitant severe stenosis (greater than 89%) of the right coronary artery (RCA), volume loading was followed by a decreased RVEF and cardiac output. In contrast, RVEF in the 17 patients without diseased RCA increased significantly, with an increase in cardiac output. Duration of aortic cross-clamping (i.e., ischemia) was more pronounced in the group with decreased RVEF due to RCA grafting. Increased end-diastolic volume and decreased RV contractility index indicated that patients with myocardial ischemia during cardiac surgery procedures sometimes were unable to make the adaptations required. We conclude that cardiocirculatory dysfunction associated with ECC may be caused by depressed RV function. Acute volume loading in this situation may lead to further deterioration of myocardial function due to RV failure, a condition which cannot be diagnosed readily at the bedside with the usual monitoring techniques.
Aged↗
Laser application in bronchology.
The use of laser in bronchology plays a major role in the therapy of benign and malignant tumours. By flexible delivery systems, lasers can be used in combination with flexible bronchoscopes. By this benign tumours, especially in young children, can be ablated successfully without major surgical intervention. In malignant tumours laser ablation can only be used as a palliative procedure in cases untreatable by conventional surgery or prior to radiation or chemotherapy, in which the symptoms of hemopthysis or significant obstruction are indications for an urgent treatment. Especially in elder patients a quick relief of symptoms can be reached avoiding the high risks of an operation. A new and experimental field of laser application in bronchology is the tracheal reconstruction with laser assistance. In 10 Beagle dogs laser assisted tracheal anastomoses revealed good functional results with an uneventful postoperative course. Histology showed a normal healing and a good reconstruction of the ciliated endothelium without metaplastic changes. So this new technique may in future become an additional tool in the reconstructive surgery of the trachea and main bronchi.
Animals↗
Use of endarterectomy as an adjunct to coronary artery bypass.
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Adult↗
[Experiences with parenteral administration of diltiazem in coronary surgery patients].
Diltiazem is a calcium channel blocker whose effects lie between those of the two other important calcium antagonists nifedipine and verapamil. In addition to vasodilation, it has a negative dromotropic effect with prolongation of the A-V interval. In animal experiments and human investigations, diltiazem improves the function of ischemic myocardium due to a direct dilating effect on coronary vessels. The purpose of the present study was to investigate the hemodynamic effects of diltiazem in patients before and during coronary revascularization. METHODS. The study included 60 consenting male patients with coronary heart disease. Twenty premedicated patients randomly received 0.3 mg/kg diltiazem or placebo within 3 min before induction of anesthesia. Hemodynamic measurements (arterial pressure, heart rate, mean pulmonary arterial pressure, pulmonary capillary pressure, right atrial pressure and cardiac output) were taken during the following 21 min. Before cannulation of the great vessels for institution of extracorporeal circulation (ECC), 20 other patients received 0.014 mg diltiazem or placebo/kg per min over 20 min. In addition to the above mentioned hemodynamic measurements, left ventricular parameters (LVP, LVEDP, dp/dt) were directly registered, and 5 min after the end of ECC the measurements were repeated with the same preload as before the ECC. Twenty additional patients received 0.014 mg diltiazem or placebo/kg per min within 21 min during ECC observing arterial perfusion pressure and oxygenator volume. RESULTS. Pre- and intraoperatively diltiazem caused a decrease in mean arterial pressure; cardiac index increased only during the preoperative investigation period (Tables 1, 2), whereas stroke volume index increased pre- and intraoperatively; heart rate decreased in all patients as well as dp/dt (Fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)
Anesthesia, General↗
[Somatosensory evoked potentials in obliterating interventions of the carotid bifurcation].
A prospective study was undertaken to determine the prognostic value of somatosensory evoked potentials during carotid artery surgery in patients where an intraluminal shunt was not used. During a three-year period 167 patients underwent 193 consecutive carotid endarterectomies under general anaesthesia. The somatosensory evoked potential after median nerve stimulation including calculation of central conduction time was used to assess cerebral function intraoperatively. Early postoperative neurologic morbidity was 3.6%, mortality 0.6%. Evoked potential changes in these patients were uniform and consisted of an increase in central conduction time of more than 20% from control (anaesthetic baseline), a decrease of the amplitude of the primary cortical response exceeding 50% and a loss of middle latency components. In subsequent recordings complete loss of the entire cortical evoked potential was observed in 5 of 7 patients. Sensitivity of CCT prolongation was 100%, specificity 89% (18 false positives). For amplitude reduction sensitivity was 86% (1 false negative), specificity 96% (7 false positives). For loss of the entire cortical response sensitivity was 71% (2 false negatives), specificity 99% (2 false positives). The above mentioned parameters correlated with postoperative neurologic state (Chi-square, p = 0.0001). Since the effects of potentially confounding variables (anaesthetics, temperature) are well known, the somatosensory evoked response, especially central conduction time, can be used as a reliable guide for brain supporting procedures.
Brain Ischemia↗
[Reaction of the sympathetic nervous system, cardiovascular parameters and endocrine stress response in disobliterating interventions of the carotid arteries. A comparison of isoflurane anesthesia and modified neurolepto-anesthesia].
In order to investigate whether the increases in mean arterial pressure (MAP) and HR during carotid endarterectomy are due to a systemic, sympathicotonic stress response and to compare two anesthetic regimens for this operation, 20 patients were randomly allocated to the following groups: (1) modified neuroleptanesthesia with midazolam, fentanyl, and vecuronium: and (2) isoflurane anesthesia with vecuronium relaxation. Premedication (pethidine, promethazine) and induction of anesthesia were similar in both groups. The plasma levels of epinephrine and norepinephrine (by HPLC/ECD), ADH, ACTH, and cortisol (by RIA), glucose, lactate, and free glycerol were determined before and after induction of anesthesia, 7 times during the operation, and 30 min after extubation. MAP and HR were measured continuously. Statistical evaluation was undertaken by analysis of variance with repeated measures on 1 factor, considering P values of less than 0.05 as significant. The endocrine parameters failed to show any remarkable increase during the entire operation period. After the end of the operation all hormones rose significantly (P less than 0.001). No correlation was found between plasma catecholamines and increases in MAP and HR. Group levels of norepinephrine and ADH were higher in the isoflurane group (P less than 0.04). It is concluded that cardiovascular reactions during carotid endarterectomy are not caused by systemic stress. Neuroleptanesthesia leads to better stress protection in the postoperative period, while isoflurane anesthesia has some advantages for the intraoperative control of arterial pressure.
Adult↗
Laser-assisted trachea anastomoses in dogs.
Tracheal anastomoses are known to be related to special surgical risks. We performed laser-assisted trachea anastomoses in 10 Beagle dogs, using an Argon-laser system and a handheld quarz fiber for energy transmission. All animals showed an uneventful postoperative course without signs of infection, air-leakage or respiratory impairment. Pathologic examination revealed no significant stenosis but a normal reconstruction of the tracheal endothelium and a normal woundhealing with only an increased connective tissue reaction. Because of the lower tensile strength of laser-assisted anastomoses in general, three adapting absorbable sutures should be left in situ to increase the resistance against mechanical stress. Under these circumstances laser-assisted anastomoses seem to be a promising additional method in the field of tracheal reconstruction and transplantation.
Anastomosis, Surgical↗
[Hemodynamic action profile of propofol in comparison with midazolam. A study in coronary surgical patients].
Propofol, a rapid and short-acting i.v. anesthetic, was associated with the risk of anaphylactic reactions in its original cremophor-EL formulation. It has been reformulated in a soybean emulsion with satisfactory anesthetic properties. A former study of hemodynamic changes after i.v. induction with propofol, thiopental, methohexital, etomidate, and midazolam in patients with coronary artery disease demonstrated that in comparison to other induction agents propofol depressed systolic and diastolic arterial pressures more severely, compromising coronary perfusion. In the present investigation left ventricular parameters as well as hemodynamic effects during extracorporeal circulation (ECC) were studied in comparison to midazolam during opiate analgesia. Methods. Hemodynamic effects of 2 mg/kg body weight propofol as compared to 0.15 mg/kg midazolam were studied in 34 patients during coronary artery surgery before cannulation of the large vessels (measurement of left ventricular parameters) or during ECC (measurement of arterial perfusion pressure and oxygenator volume). Results (see Table 1, Figs. 1 and 2). Propofol decreased systolic and diastolic pressures (-27%, -22%) more than midazolam (-10%, -9%). Cardiac index and stroke volume index were diminished following both drugs (propofol: -14%, -9%; midazolam: -15%, -11%); total systemic resistance was reduced significantly by propofol (-22%). Dp/dtmax was compromised more markedly by propofol (-24%) than by midazolam (-18%), but there was no significant difference.(ABSTRACT TRUNCATED AT 250 WORDS)
Anesthesia↗
PTFE grafts to the right coronary artery following endarterectomy.
In ten of 3031 patients undergoing coronary surgery, we used a PTFE graft for bypass to the right coronary artery following endarterectomy. Diffuse calcification was the reason for endarterectomy of the right coronary artery in all cases. We chose a PTFE graft only in those cases where autologous grafts were not available in a sufficient number. After a mean follow-up period of twelve months nine of the ten grafts were patent.--This study demonstrates that under selected circumstances PTFE grafts can be successfully used in coronary surgery if autologous grafts are lacking.
Blood Vessel Prosthesis↗
[Isolated modification of the vascular system by vasopressor agents (akrinor, etilefrin, ephedrine, norfenefrine, amezinium) during extracorporeal circulation in man].
The influence of different vasopressors (Akrinor, etilefrine, ephedrine, norfenefrine, ameziniummetilsulfate) on arterial perfusion pressure and oxygenator volume during extracorporeal circulation was compared to a control group. All substances led to an increase in perfusion pressure, thus demonstrating a direct influence on arterial vessels. The rise in arterial pressure after injection of ameziniummetilsulfate persisted during the investigation period, whereas norfenefrine led to a short-lasting, but massive increase. No rise in venous tone was noticed during the investigation period.
2-Hydroxyphenethylamine↗