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Biomedical subjects

R Hetzer

Publications and source records attributed to R Hetzer.

At least 217 records · Page 12Linked to original sources
PubMed1998

["Cox/Maze-III operation" as surgical therapy of chronic atrial fibrillation during mitral valve and atrial septal defect II operation].

PROBLEM: Atrial fibrillation is associated with significant morbidity and mortality. The increased risk of thromboembolism makes constant anti-coagulation necessary, while the absence of atrial contraction worsens the hemodynamic situation. In this study we examined the results of simultaneous surgical treatment of chronic atrial fibrillation through "Cox/Maze-III-procedure" while mitral valve surgery and atrial septal closure. PATIENTS AND METHODS: Between February 1995 and July 1997 sixteen patients aged 50 to 72 y (mean: 59 y) underwent open heart surgery (mitral valve replacement n = 10, reconstruction n = 3; mitral valve reconstruction and atrial septal closure n = 1, atrial septal closure n = 1, thrombectomy from left atrium n = 1) and "Cox/Maze-III-procedure" in one session. Preoperative duration of chronic atrial fibrillation was between 2 and 12 y (mean: 5.0 y). The patients were examined preoperatively and postoperatively 3, 6, 12, and 24 months after surgery using the following methods: transesophageal echocardiography (TEE), ECG, long-term ECG, and stress ergometry. RESULTS: During the early postoperative period (< 7 d) all of the patients were in sinus rhythm or atrial pacing; eight patients intermittently had atrial fibrillation. In the follow-up period from 1 to 27 months (mean 14 months), 15 patients have a stable sinus rhythm (94%). One patient, preoperatively known to have intermittent tachybradycardia, received a pacemaker 2 months postoperatively for sinus bradycardia. Postoperatively in TEE patients showed left atrial contraction with improvement of hemodynamic situation. Stress ergometry 6 months postoperatively showed lower increasements of heart rate, at 12 months normal frequency. CONCLUSION: The surgical treatment of chronic atrial fibrillation through "Cox/Maze-III-procedure" can be performed combined with other heart operations without increased perioperative or postoperative risks. The Maze-procedure is an effective surgical therapy of chronic atrial fibrillation. Postoperatively there is an improvement of the hemodynamic situation because of sinus rhythm and synchrone atrioventricular contraction.

Aged↗
PubMed1998

[Measuring bioelectric myocardial impedance as a noninvasive method for diagnosis of graft rejection after heart transplantation].

12 beagle dogs underwent neck-heart transplantation and were immunosuppressed with cyclosporine and methylprednisolone. Intramyocardial impedance was determined twice daily with four screw-in electrodes in the right and left ventricle. Transmyocardial biopsies and the intra-myocardial electrogram (IMEG) were performed as reference methods. 19 rejection episodes were induced. When acute rejection was seen in histology the animals were treated with pulsed 125 mg methylprednisolone over 5 consecutive days and immunosuppression was raised to sufficient levels. Successful treatment of rejection was controlled by biopsy. All hearts showed a uniform decrease of impedance of about 28.3% +/- 5.5% immediately after implantation, then reaching a stable plateau after 7 to 8 days. Impedance values then remained unchanged as long as rejection was absent. Biopsy findings of grade 1A to 1B (ISHLT) were accompanied by a statistically significant increase of impedance of 12.2% +/- 2.5%, of grade 2 to 3A of 19.2% +/- 3.2%, and of grade 3B to 4 of 27.0% +/- 2.9%. Sensitivity was 95%, specificity 91%. Successful treatment of rejection led to a uniform decrease of impedance to intramyocardial impedance for high frequencies can reliably indicate alterations of the cell membrane and the intracellular space during acute cardiac allograft rejection. The amount of increase of impedance is a reliable noninvasive parameter to graduate acute cardiac allograft rejection. The success of treatment of rejection can also be monitored by impedance. This noninvasive method is applicable for telemetric rejection monitoring via an implantable device, which would allow continuous rejection surveillance of a patient at home without hospital admission.

Animals↗
PubMed1998

Complement and contact activation during cardiovascular operations in infants.

BACKGROUND: By comparing the results of cardiac operations with or without cardiopulmonary bypass (CPB) in infants in a prospective study, we sought to determine which part of the postoperative systemic inflammatory response was caused by CPB. METHODS: Thirty-five patients were divided into two groups: 11 infants operated on without CPB and 24 infants operated on with CPB. Blood samples were drawn before, during, and after the operation. We assessed complement function and the concentrations or activities of C1q, C3, C4, C1 inhibitor, factor B, the activated split product C3a, and prekallikrein and factor XIIa of the contact system. RESULTS: All of the patients exhibited a decrease of complement proteins. This was greater in infants who underwent CPB. A increase in C3a and factor XIIa and changes in prekallikrein activity occurred only in infants during CPB. CONCLUSIONS: Complement activation occurs in all infants, but is significantly higher in the group with CPB. Contact activation only occurs in patients who undergo CPB. Thus, the inflammatory response is caused by the use of a CPB circuit and to a lesser degree by surgical procedures and anesthesia.

Cardiac Surgical Procedures↗
PubMed1998

Coronary bypass flow during use of intraaortic balloon pumping and left ventricular assist device.

BACKGROUND: Intraaortic balloon pumping (IABP) and left ventricular assist device (LVAD) are used for left ventricular support when low cardiac output occurs after a coronary bypass operation for serious coronary artery disease. There are hemodynamic differences in blood flow in various kinds of coronary artery bypass grafts, caused by their inherent physiologic characteristics. The hemodynamic effects of left ventricular assistance with IABP and LVAD on blood flow through various coronary artery bypass grafts were investigated. METHODS: An ascending aorta-coronary bypass graft (ACB), an internal thoracic artery, and a descending aorta-coronary bypass graft were anastomosed to the left anterior descending coronary artery in a canine model. In this experimental model, the blood flow to the same coronary bed in the three types of grafts could be evaluated. Blood flow in the left anterior descending coronary artery through the three types of coronary bypass grafts was studied in this model during or in the absence of ventricular assistance. RESULTS: In the control study, the systolic blood flow did not differ among the three types of grafts, but the diastolic flow decreased in the following order: with the ACB, the internal thoracic artery, and the descending aorta-coronary bypass graft. The systolic flow during IABP and LVAD was similar to the control flows. Use of IABP increased the diastolic flow by 75.3%+/-12.4% of the control value in the ACB, 37.9%+/-25.0% in the internal thoracic artery, and 21.2%+/-11.4% in the descending aorta-coronary bypass graft. The LVAD increased the diastolic flow by 97.7%+/-18.7% of the control value in the ACB, 64.5%+/-25.7% in the internal thoracic artery, and 63.0%+/-27.9% in the descending aorta-coronary bypass graft. The diastolic blood flows in the left anterior descending coronary artery and the three types of grafts were significantly greater with IABP than the control values, and significantly greater with LVAD than with IABP and the control values. The degrees of increase of diastolic flows in the left anterior descending coronary artery and the ACB with IABP and LVAD were significantly greater than in the arterial grafts (p < 0.01). CONCLUSIONS: The diastolic flows in the internal thoracic artery and descending aorta-coronary bypass graft increased less than in the native left anterior descending coronary artery and ACB during left ventricular assistance, particularly with IABP. It is important for the selection of tactics for the management of catastrophic status after coronary bypass grafting to consider the hemodynamic characteristics of the graft.

Animals↗
PubMed1998

Daily noninvasive rejection monitoring improves long-term survival in pediatric heart transplantation.

BACKGROUND: Acute rejection episodes and transplant vasculopathy (TVP) account for most of the late deaths after heart transplantation in both adults and children. Accumulating evidence indicates that fatal acute rejection and TVP are related to unrecognized and untreated early and ongoing acute rejection. Day-by-day surveillance of the heart and prompt treatment of any rejection may yield improved long-term survival. METHODS: In almost all patients having transplantation at our institution (978 patients since 1986), the intramyocardial electrogram (IMEG) was recorded routinely every day through a telemetry pacemaker and transmitted to our center by telephone modem. Earlier studies showed a substantial voltage drop in the IMEG QRS complex is highly indicative of acute rejection, including humoral rejection. In this study, we reviewed the data from 69 pediatric patients up to 16 years old for the incidence of acute rejection, TVP, and long-term outcome. Diagnostic endomyocardial biopsies were performed in only 10 patients, and recent coronary angiograms from 29 children were reviewed. RESULTS: In 50 children discharged after heart transplantation, IMEG surveillance data for a mean of 2.9 years indicated 72 acute rejection episodes. During follow-up of 1 month to 10.5 years (mean follow-up, 4.4 years), 2 patients died late of causes unrelated to either rejection or TVP. Another patient died of rejection during unrecognized underimmunosuppression nearly 8 years after transplantation and nearly 31/2 years after discontinuing IMEG recordings. Two patients without IMEG recording died of acute rejection or late TVP. In 1 patient, moderate TVP was seen on an angiogram after 41/2 years (incidence, 2.0%; 5-year incidence, 5.6%). CONCLUSIONS: Daily recording of the IMEG can reliably detect early stages of acute rejection episodes, and immediate rejection treatment seems to keep the incidence of TVP low. The IMEG appears better than all the other rejection monitoring protocols currently in use.

Acute Disease↗
PubMed1998

Circulatory support with pneumatic paracorporeal ventricular assist device in infants and children.

BACKGROUND: Mechanical circulatory support in intractable heart failure in children has been limited to centrifugal pumps and extracorporeal membrane oxygenation: Since 1990 small adult-size pulsatile air-driven ventricular assist devices "Berlin Heart" (VAD) and, since 1992 miniaturized pediatric VAD (12, 15, 25, 30 mL pumps), have been used in our institution. Since 1994 the blood-contacting surfaces of the device system have been heparin-coated. In this report the experiences with VAD support in 28 children are presented. METHODS: In 28 children-ages between 6 days and 16 years-the Berlin Heart VAD has been applied for periods of between 12 hours and 98 days (mean, 16.9 days) aiming at keeping the patient alive and allowing for recovery from shock sequelae until later transplantation or myocardial recovery. There were three groups. Group I: with primary intention of "bridge-to-transplantation" in various forms of cardiomyopathy (n = 13) or chronic stages of congenital heart disease (n = 5). Group II: "Rescue" in intractable heart failure early after corrective surgery for congenital heart disease (n = 4) or in early graft failure after a heart transplantation (n = 1). Group III: "Acute myocarditis" (n = 5) aiming at either myocardial recovery or transplantation. Twelve were brought to the operating room under cardiac massage and 25 had been on the respirator for more than 24 hours. RESULTS: Twelve patients died on the system from sequelae of profound shock-multiorgan failure, sepsis, loss of peripheral circulatory resistance-or from hemorrhagic complications (n = 4) or brain death (n = 1). Thirteen patients (groups I and III) were transplanted after support periods of between 3 and 98 days with 7 long-term survivors living now up to 7.5 years (mean, 4.4 years). Three patients (groups II and III) were weaned from the system with two long-term survivors (both in group III). There were no patients in group II who survived and the "rescue" indication has been discarded for VAD since 1992. Such patients are since treated by extracorporeal membrane oxygenation (ECMO) in our institution. Out of the 8 patients placed on VAD during 1996 and 1997, 7 were successfully supported until transplantation or weaning. Thirteen patients were extubated and mobilized on the system. Whereas with the earlier systems thrombi in the blood pumps were seen in 15 instances and 2 patients suffered from thromboembolic complications, no thrombotic events occurred with the heparin-coated systems. CONCLUSIONS: After accumulating clinical experience and several technical improvements since 1990 the use of the pediatric Berlin Heart VAD has matured into a reliable and safe system to keep patients with otherwise intractable heart failure alive until complete myocardial recovery is reached or transplantation becomes feasible. Whereas heart failure early after cardiac operation is now primarily treated by ECMO, acute myocarditis appears to be a promising precondition for complete cardiac recovery during VAD support.

Adolescent↗
PubMed1998

A modified repair technique for tricuspid incompetence in Ebstein's anomaly.

OBJECTIVE: A modified technique for tricuspid valve repair in Ebstein's anomaly restructures the valve mechanism at the level of the true tricuspid anulus by using the most mobile leaflet for valve closure without plication of the atrialized chamber. Midterm results of this therapeutic approach for patients with Ebstein's anomaly and tricuspid valve incompetence are reported. METHODS: Between October 1988 and April 1997, the incompetent tricuspid valve was repaired with our technique in 19 patients (12 female, 7 male; 2 to 54 years, mean 21 years). The indication for operation was congestive heart failure of various degrees in all patients. Tricuspid incompetence was grade II in two patients, grade III in 14, and grade IV in three. Associated congenital malformations were simultaneously repaired (interatrial communication in 18, ventricular septal defect in two, pulmonary stenosis in two, mitral valve prolapse in one). Follow-up ranged between 10 and 103 months (median 28 months) and was complete for all patients. RESULTS: There were no operative deaths. One patient with active endocarditis and pulmonary abscess died 2 months after the operation of recurrent sepsis; there were no late deaths. During follow-up, New York Heart Association functional class improved from 2.8 before the operation to 1.9 without recurrent cyanosis, and tricuspid incompetence decreased from a mean grade of 3.1 to one of 0.9, without any echocardiographic deterioration of the tricuspid valve function or right ventricular dilation. CONCLUSIONS: Our technique allows tricuspid valve repair in patients with Ebstein's anomaly, even in cases usually reserved for primary valve replacement, without late functional deterioration.

Adult↗
PubMed1998

Transient sinus node dysfunction after the Cox-maze III procedure in patients with organic heart disease and chronic fixed atrial fibrillation.

OBJECTIVES: This prospective study examined types, frequency and time dependency of the electrophysiologic manifestation of the sinus node dysfunction after the Cox-maze III procedure--the technique of choice for the management of medically refractory atrial fibrillation-in patients with organic heart disease, chronic fixed atrial fibrillation and no preoperatively overt dysfunction of the sinus node. BACKGROUND: The original maze procedure was modified twice in order to reduce the high incidence of the sinus node inability to generate an appropriate sinus tachycardia in response to maximal exercise, and occasional left atrial dysfunction. Despite these modifications, postoperative disturbance of sinus node function can be frequently observed. METHODS: In 15 adult patients, standard electrocardiogram, 24-h Holter monitoring, power spectral analysis of heart variability, exercise testing, Valsalva maneuver and rapid positional changes were performed 3, 6 and 12 months after the Cox-maze III procedure and mitral valve surgery or closure of atrial septal defect. RESULTS: Electrocardiographic manifestations of sinus node dysfunction were identified in 12 patients at 3 months, in 6 patients at 6 months, and in 0 patients at 12 months after surgery. The heart rate response to exercise during the first 6 months was reduced in the maze group and became fully normal at 12 months. Power spectral analysis of heart rate variability showed very low power values at 1 month with inhibited cardiac autonomic activity and no response on sympathetic stress. A potential of recovery of cardiac autonomic activity was documented 12 months after surgery. CONCLUSIONS: The manifestations of sinus node dysfunction following the Cox-maze III procedure were time dependent and their frequency and intensity progressively decreased and disappeared within 12 months after surgery.

Aged↗
PubMed1998

Successful surgical treatment of a giant aneurysm of the right coronary artery.

We describe the case of a 46-year-old female patient, who was referred to us under the suspicion of an acute type-A aortic dissection. After perusal of the computer tomogram and subsequent transesophageal echocardiography, we decided to operate, albeit under the assumption of the existence of a pericardial cyst. Intraoperatively a strikingly large aneurysm of the right coronary artery presented itself, which was successfully treated through resection and end-to-end anastomosis.

Anastomosis, Surgical↗
PubMed1998

Coronary angioplasty, bypass surgery, and retransplantation in cardiac transplant patients with graft coronary disease.

BACKGROUND: Graft coronary disease (GCD) remains the single greatest limitation to long-term survival of heart transplant recipients. Therapeutic strategies for the prevention or retardation of GCD in the cardiac allograft are limited; palliative coronary revascularization has been attempted. Because of the high mortality rate associated with advanced forms of GCD our institution offers the option of retransplantation in selected cases. The aim of this study was by analyzing retrospectively the outcomes of angioplasty, coronary bypass grafting, and retransplantation in cardiac transplant patients to attempt to identify subgroups of transplant recipients with graft coronary disease who may profit from myocardial revascularization. METHODS: Of the 989 patients undergoing 1016 heart transplantations (HTx) at our institution between 10/86 and 12/97, all were screened for the development of GCD. Analyzing routinely annual angiography, intracoronary ultrasound in defined study patients, and autopsy findings, GCD was diagnosed in 124 patients (110 male, 14 female) 2 to 107 months after HTx (mean 30 months). RESULTS: PTCA: Fourty-six out of 124 patients underwent 76 angioplasties at a mean of 50 +/- 30 months (range 4-91 mo) following cardiac transplantation. The primary success rate was 96% (73/76). The reason for the unsuccessful angioplasty attempts (n = 3) was failure to completely penetrate a stenosis of LAD in 2 patients and severe dissection of RCA, which required emergency surgery, in one. Angiographic restenosis occurred in 42% (31 of 76 lesions) and was diagnosed 11 +/- 11 months after the first angioplasty. There was no procedure-related death. CABG: Seven patients underwent bypass surgery at a mean of 67 months (range 6-128 months) after HTx. Elective surgery was performed in 2 patients with proximal severe triple-vessel disease (Type A lesion) and in 1 patient with severe tricuspid regurgitation who received a tricuspid valve replacement and concomitant single-vessel bypass surgery for proximal GCD (Type A lesion). One patient with combined Type A and B/C lesions required emergency surgery for dissection of RCA after an angioplasty procedure. Three patients with post-infarction unstable angina developed worsening congestive heart failure which required emergency surgery. Angiographically all these patients showed diffuse, distal arteriopathy (combined Type B/C lesions). The electively operated patients and the patient with dissection of RCA were successfully treated and survived beyond hospital discharge (overall survival for CABG in GCD patients 4/7 = 57%). After a mean follow-up of 10 months (range 2-32 months) all are in good clinical condition. All 3 patients with distal arteriopathy and emergency surgery died in hospital of left-ventricular failure (43%). Retransplantation: Eight patients underwent retransplantation at a mean of 54 months (range 6-96 months) after HTx. Six of 8 patients had successful operations and survived beyond hospital discharge with a one-year-survival rate of 75%. In a mean follow-up of 31 months (5-68 months) 3 of 6 retransplant recipients developed a recurrence of GCD. CONCLUSION: The presence of angiographic distal arteriopathy should be considered a significant factor in patient selection for coronary revascularization procedure. Coronary angioplasty is to be considered as a method of treatment for severe, local stenoses (Type A lesion). PTCA may be applied in these selected cardiac transplant recipients with primary success and complication rates comparable to routine angioplasty but with an increased rate of restenosis especially in small vessels (diameter < 2.5 mm). The distinction between Type A lesions in large (diameter > or = 2.5 mm) and small vessels may be important not only with respect to restenosis but also with respect to long-term benefit. The overall survival did not differ between GCD patients with and without PTCA, suggesting this treatment to be largely palliative. (ABSTR

Angioplasty, Balloon, Coronary↗
PubMed1998

Percutaneous dilatational tracheostomy: results and long-term outcome of critically ill patients following cardiac surgery.

BACKGROUND: Tracheostomy is widely regarded as the method of choice for long-term airway control in critically ill patients. The advantages of tracheostomy have to be balanced against the surgical risks of conventional surgical tracheostomy. However, the alternative technique of percutaneous dilatational tracheostomy (PDT) has been associated with fewer procedure-related complications. METHODS: The results of PDT following cardiac surgery were investigated in a prospective study (1/1995-9/1997). The procedure of Ciaglia (1985), a modified Seldinger technique, was performed under endoscopic guidance in 88 patients, 30 women and 58 men, with a mean age of 56.6+/-14.5 years. RESULTS: PDT was successfully performed in all cases after a mean of 14.6+/-9.0 days of translaryngeal intubation. No serious procedural complications occurred; a minor hemorrhage occurred in 12 patients and a cuff defect in 2 patients. 49 patients (55.7%) were weaned from mechanical ventilation, and 45 patients (51.1%) were decannulated after a mean tracheostomy duration of 18.9+/-27.2 days. 38 patients died of their underlying disease while still being mechanically ventilated. A total of 20 postprocedural complications were observed in 15 patients: stomal infection (7), minor hemorrhage (4), tracheal stenosis (3), tube displacement (2), delayed wound healing (2), soft-tissue hemorrhage (1), and organ hemorrhage (1). During long-term follow-up a good functional and cosmetic result could be documented in the majority of 35 patients. CONCLUSIONS: PDT can be performed safely in patients following cardiac surgery as a bedside technique with a low incidence of procedural and postprocedural complications and an acceptable functional and cosmetic long-term outcome. Further studies are needed to define the optimal timing of PDT after translaryngeal intubation.

Aged↗
PubMed1998

Secondary transmyocardial laser revascularization in the treatment of end-stage coronary artery disease.

Transmyocardial laser revascularization (TMR) has received more acceptance within the last few years. The vast majority of TMR users report impressive clinical benefits. The underlying mechanism for benefit by TMR, however, remains somewhat unclear. Between July 1994 and September 1997, 165 patients underwent TMR at our institution. In three of our TMR patients after an initial angina-free interval of 1 to 2 years we decided to repeat the laser operation. This article focuses on the three re-TMR patients who underwent a second TMR operation 12 to 14 months after the first one. Two of the three patients are well and experience significantly less angina than preoperatively.

Coronary Disease↗
PubMed1998

Transmyocardial laser revascularization in the treatment of end-stage coronary artery disease.

Transmyocardial laser revascularization has been used in 171 patients suffering from severe angina pectoris unresponsive to medical therapy at Deutsches Herzzentrum Berlin within the period from 7/1994 to 12/1997. In all patients conventional bypass surgery or PTCA, did not seem to offer the possibility of success. Postoperatively, the majority of the patients experienced a significant decrease in angina and better physical endurance. A statistically significant increase in myocardial perfusion or left ventricular contractility has not been detected. Perioperative mortality after TMR decreased from 8% among the first 40 patients to 2.5% among the 40 patients operated on most recently, with an overall mortality of 7%. The relief of angina symptoms and the improved quality of life after TMR seems to justify the use of the method in patients who presented with urgent indications for CABG surgery, although their coronary vessel status did not seem to promise success for this procedure. However, considering its experimental foundation and long-term effects, it seems that a conclusive assessment of TMR is not yet possible.

Angina Pectoris↗
PubMed1998

European Multicenter Tacrolimus (FK506) Heart Pilot Study: one-year results--European Tacrolimus Multicenter Heart Study Group.

BACKGROUND: Tacrolimus (FK506) may represent a major advance in the management of allograft rejection after solid organ transplantation. In August 1994 a European heart transplantation pilot study was initiated to assess the efficacy and safety of tacrolimus when administered exclusively through an oral route. METHODS: Eighty-two heart transplant recipients were randomized to treatment (2:1 ratio) with either tacrolimus- (n=54) or cyclosporine-based therapy (n=28). RESULTS: No significant differences were evident between the two treatment groups in either rejection or survival rates at 1 year. Kaplan-Meier estimates of the freedom from rejection were 26.3% and 18.5%, respectively, for the tacrolimus and cyclosporine treatment groups (p=.444). Survival rates were 79.6% and 92.9% (p=.125). At 3 of the 5 centers, patients received antithymocyte globulin during the immediate postoperative period and fared better than those who did not (with acute rejection-free rates of 49.2% and 26.7% for tacrolimus and cyclosporine, respectively [p=.080], as opposed to 7.1% and 8.3% [p=.965]; patient survival rates of 84.6% and 93.3% [p=.382] vs 75.0% and 92.3% [p=.243]). The overall rates of infection, impaired renal function (31.5% vs 21.4%), and glucose intolerance (7.0% vs 4.3%) did not differ significantly between the tacrolimus and cyclosporine treatment groups. Tacrolimus seemed to possess an advantage with regard to a reduced requirement for antihypertensive therapy (59.5% vs 87.5%, p=.025). CONCLUSIONS: Immunosuppression with oral tacrolimus provides a viable alternative to treatment with cyclosporine, particularly when administered in conjunction with antibody therapy. Further studies are warranted to optimize the administration of tacrolimus in this indication.

Administration, Oral↗