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Biomedical subjects

G Laufer

Publications and source records attributed to G Laufer.

At least 19 recordsLinked to original sources
PubMed1995

ICD therapy in survivors of sudden cardiac death awaiting heart transplantation.

The impact of implantable cardioverter defibrillator (ICD) therapy on survival of heart transplant candidates is of major socioeconomic and ethical interest. However, efficacy is even uncertain for patients at highest risk of tachyarrhythmic death on the waiting list. We studied 60 selected heart transplant candidates (mean age, 55.8 years; mean left ventricular ejection fraction, 0.15; functional class III and IV) with a history of successful resuscitation by external electric defibrillation for spontaneous, syncopal ventricular tachyarrhythmia during the study period from March 1992 through September 1994. At the time of registration for transplantation, 30 patients had ICD devices implanted, whereas 30 patients lacked ICD therapy for various nonmedical reasons. Both therapy groups were comparable in clinical and hemodynamic characteristics as well as in intention to transplant (median waiting time to transplantation, 5.7 and 6 months, respectively; not significant by log-rank method). Survival on the waiting list was significantly improved by ICD therapy; only 1 of the 30 ICD patients (19 transplanted) but 7 of the 30 non-ICD patients (14 transplanted) died on the waiting list (p < 0.05 by log-rank method). Implantable cardioverter defibrillator therapy did not affect survival after transplantation as compared with non-ICD patients (not significant by log-rank method). During the waiting time, 26 of the ICD patients (87%) experienced adequate ICD discharges, and 12 of the non-ICD patients were treated successfully by external electric defibrillation (40%).(ABSTRACT TRUNCATED AT 250 WORDS)

Death, Sudden, Cardiac↗
PubMed1995

The impact of implantable cardioverter-defibrillators on mortality among patients on the waiting list for heart transplantation.

Implantable cardioverter-defibrillators were investigated for their impact on mortality in 228 consecutive heart transplant candidates on the waiting list for transplantation (207 patients without and 21 with implantable cardioverter-defibrillator therapy). The mortality rate in 207 patients without implantable cardioverter-defibrillator therapy was 23.2% and in 21 patients with implantable cardioverter-defibrillator therapy was 4.7%. In a Cox proportional hazards model for all 228 study patients (mortality while on the waiting list: 21.5%; transplantation rate: 54.8%), the absence of an implantable cardioverter-defibrillator was only a marginally significant predictor of mortality (p = 0.079). However, the absence of an implantable cardioverter-defibrillator was a powerful predictor of mortality for a subgroup of 134 patients with high-grade ventricular arrhythmias on Holter electrocardiography (mortality while on the waiting list: 26.1%; transplantation rate: 54.5%; p = 0.022) and for a subgroup of 58 survivors of sudden cardiac death (mortality while on the waiting list: 22.4%; transplantation rate: 56.9%; p = 0.018). Implantable cardioverter-defibrillator therapy can be strongly recommended in transplant candidates with a history of sudden cardiac death. Recommendations for an expanded, prophylactic use of implantable cardioverter-defibrillator therapy in heart transplant candidates cannot be given.

Arrhythmias, Cardiac↗
PubMed1995

[Efficacy of the implantable cardioverter-defibrillator in patients on the waiting list for heart transplantation].

8 of 122 patients receiving an implantable cardioverter defibrillator (ICD) in our department since 1985 for the treatment of ventricular tachyarrhythmias were considered candidates for cardiac transplantation. In 6 of 8 patients, at least one successful ICD discharge (range 1-378 discharges) was documented in the follow up time until transplantation. These therapies included cardioversions/defibrillations as well as overdrive stimulation in sustained monomorphic ventricular tachycardia. 1 patient died shortly before receiving a compatible organ. The remaining 7 patients survived successful heart transplantation undertaken 7-34 months after implantation of the cardioverter defibrillator. Cardiac transplantation was not complicated in any of these patients by the previous ICD management. Our results show the high efficacy of ICD as "bridge to transplant" therapy unit cardiac transplantation.

Adult↗
PubMed1995

Surgical treatment of type A aortic dissections. Results with profound hypothermia and circulatory arrest.

Type A aortic dissection still presents an emergency situation in cardiac surgery that is associated with high morbidity and mortality rates. There has been a significant improvement in the surgical outcome since the introduction of deep hypothermia and circulatory arrest. In this study, we discuss our results after operative repair of ascending aortic dissections, using deep hypothermia and circulatory arrest. This study presents the results of 67 patients (43 men, 24 women) from 18 through 81 years of age (mean, 54 years) who underwent surgery for type A dissecting aneurysm over a period of 4 years. Type A dissection (52 acute and 15 chronic cases) was due to Marfan syndrome in 12 patients, to atherosclerotic disease of the aorta in 27 patients, and to traumatic injury in 1 patient. Hypertension as the only pathologic finding was observed in 27 patients. Deep hypothermia (confirmed by isoelectric electroencephalogram) and circulatory arrest were induced in all patients. Two patients died intraoperatively due to massive bleeding (intraoperative mortality, 3%). The 30-day mortality rate was 30% (n = 20). Causes of perioperative deaths in order of frequency were multi-organ failure (n = 11), myocardial infarction (n = 2), postoperative bleeding (n = 2), cerebrovascular insult (n = 2), and sepsis (n = 1). The mean intensive care unit stay of the surviving 47 patients (72%) was 8 days, followed by a mean of 21 additional days in the hospital. Our experience with profound hypothermia and circulatory arrest, used in combination with coated grafts, supports our conviction that this is the method of choice for the treatment of type A dissecting aneurysm.

Adolescent↗
PubMed1995

[Surgery of thoracic and thoraco-abdominal aneurysms using deep hypothermia and cardiovascular arrest with continuous administration of blood cardioplegia].

Between January 1991 and February 1993, 14 patients (3 female, 11 male) aged between 21 and 79 years (mean 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, in 3 patients coronary artery by pass grafting was performed before. All patients were operated using cardiopulmonary bypass with continuous blood cardioplegia, hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, 0-EEG) and posterolateral exposure. All patent lower intercostal and lumbar arteries (Th3-L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0, after replacement of the thoracoabdominal aorta 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurologic deficit, renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic and 18 days for patients after replacement of the thoracoabdominal aorta. Our results indicate the method of elective hypothermia and circulatory arrest effective in spinal cord protection. The increase in the tolerable duration of spinal cord ischemia supports the reimplantation of all intercostal and lumbar vessels.

Adult↗
PubMed1994

Endomyocardial HLA expression is increased to the same extent in idiopathic and secondary dilated cardiomyopathy.

In a total of 22 failing hearts from human transplant recipients, the expression of major histocompatibility complex (MHC) molecules, the CD phenotype of infiltrating mononuclear cells, and the number of fibroblasts were analyzed by immunohistochemistry. Compared with 10 non-failing control hearts, significantly higher morphometric area fractions of HLA-ABC and HLA-DR with a concomitant increase of CD3-, CD4- and CD8-positive cells were found to be comparable in 12 patients with idiopathic dilated cardiomyopathy and in 10 patients with secondary heart failure. Furthermore, the similarity of T-cell activation in idiopathic and secondary variants of the disease were substantiated by the following observations: (1) the site-specific distribution of MHC molecules and mononuclear cells in the myocardium was comparable in idiopathic and secondary dilated cardiomyopathy; (2) 6 individuals with lymphocytic aggregates in their myocardium in association with the highest levels of HLA-ABC expression were equally distributed among idiopathic and secondary patient subsets; and (3) expression of HLA-ABC and HLA-DR correlated with that of an endothelial cell marker, von Willebrand factor, in failing myocardia of both study groups. In conclusion, no difference was found in increased MHC molecule expression in failing myocardium of idiopathic and secondary variants of dilated cardiomyopathy, and these entities were not differentially associated with infiltration by increased numbers of T lymphocytes. Hence, we postulate that these immunopathological features are consequences rather than causative factors of myocardial degeneration and dilatation.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathy, Dilated↗
PubMed1994

Sinus node dysfunction after orthotopic heart transplantation: the Vienna experience 1987-1993.

In the present study, the annual incidence of postoperative sinus node dysfunction and the type of sinus node abnormality after cardiac transplantation were followed over a 6 1/2-year period in 185 patients. Each year the sinus node function was systematically characterized by rhythm and corrected sinus node recovery time in a significant number of patients. Over the entire study period, there were 131 patients with normal sinus node function (corrected sinus node recovery time 318 +/- 55 msec) while 54 patients had latent (n = 24, sinus rhythm, corrected sinus node recovery time 8,053 +/- 2,198 msec) or manifest (n = 30, absence of sinus rhythm or pacemaker dependence) sinus node dysfunction. Twenty-nine patients had pacemaker placement. The incidence of sinus node dysfunction declined in absolute terms and when indexed by the actual number of patients transplanted per year (index 1987: 38.5; 1998: 17.6; 1989: 23.2; 1990: 29.1; 1991: 10.4; 1992: 7.5; 1993: 2.2). Among those with sinus node dysfunction, the annual percentage of patients presenting with prolonged recovery time, escape rhythm, and those reverting back to sinus rhythm until discharge did not change significantly over the study period (P = 0.22). On multivariate analysis, only the date of transplantation was significantly associated with the occurrence of postoperative sinus node deficiency (P = 0.0007) while age of recipient (P = 0.85) or donor (P = 0.96), the type of cardioplegia used (P = 0.09) and ischemic time (P = 0.09) were insignificant.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1994

Thoracoabdominal aneurysm repair: spinal cord protection using profound hypothermia and circulatory arrest.

Between January 1991 and February 1993, 14 patients (11 male, 3 female) between 21 and 79 years of age (median 50 years) underwent reconstruction of the thoracic (n = 7) and thoracoabdominal aorta (n = 7). Four patients had previously undergone operation of the ascending aorta, and in three patients coronary artery bypass grafting had previously been performed. All patients were operated on a via a posterolateral thoracotomy using cardiopulmonary bypass with continuous blood cardioplegia and hypothermic circulatory arrest (11 degrees C nasopharyngeal temperature, flat-EEG). All patent lower intercostal and lumbar arteries (T3 to L5) were reimplanted. The 30-day mortality after repair of the thoracic aorta was 0%; after replacement of the thoracoabdominal aorta, mortality was 28.5% (n = 2). One patient died 70 days after replacement of the thoracic aorta as a consequence of a perioperative stroke. None of the surviving 11 patients developed a permanent neurological deficit or renal or cardiac dysfunction. The average intensive care stay was 6 days for patients after replacement of the thoracic aorta and 18 days for patients after replacement of the thoracoabdominal aorta. Our results suggest that use of elective hypothermia and circulatory arrest for spinal cord protection is highly effective. We, therefore, recommend this method for complex reconstructions of the thoracoabdominal aorta.

Adult↗
PubMed1994

Pregnancy and spontaneous delivery 13 months after heart transplantation.

This case report is about a 23-year-old female patient who underwent heart transplantation because of dilatative cardiomyopathy. Four months after transplantation she conceived. Thirteen months postoperatively, the patient had spontaneous vaginal delivery and gave birth to a child in good physical condition.

Adult↗
PubMed1994

Aprotinin does not decrease early graft patency after coronary artery bypass grafting despite reducing postoperative bleeding and use of donated blood.

Forty-five male patients with planned coronary artery bypass operation were randomized in a double blind fashion to receive either 6 million kallikrein inactivator units of aprotinin (high-dose group), 2 million kallikrein inactivator units of aprotinin (low-dose group), or placebo (control group). Postoperative bleeding was significantly decreased in both aprotinin groups in comparison to that in the control group (590 ml [290 to 1800 ml] high-dose group and 650 ml [280 to 1900 ml] low-dose group versus 920 ml (350 to 2700 ml) control group, p < 0.001). There was no difference between the two aprotinin groups. The need for postoperative blood transfusion was significantly lower in the aprotinin groups (1.46 [0 to 4] blood units high-dose group and 1.65 [0 to 5] blood units low-dose group versus 2.43 [0 to 7] blood units control group, p < 0.05). All patients underwent coronary angiography between the seventh and twelfth postoperative day. No difference was found among the three groups in patency of vein grafts-93.8% in the high-dose group, 94.5% in the low-dose groups, and 93.3% in the control group. Therefore, aprotinin significantly reduced postoperative bleeding and transfusion requirement after coronary artery bypass grafting without influencing early graft patency.

Aprotinin↗
PubMed1993

Pulmonary autograft valve replacement in the dilated and asymmetric aortic root.

Pulmonary autograft aortic valve replacement is the only technique for implantation of a biologic, vital and thus nondegenerating valve. The technique of root replacement overcomes problems of asymmetric aortic roots and reduces the risk of malalignment, but bears the risk of dilatation. We have performed pulmonary autograft aortic root replacement in 20 patients (mean age 22 years, range 5-38). Twelve presented with aortic incompetence, 3 with stenosis and 5 with combined defects. Initially roots were implanted just supraannularly with two running suture lines. As the neo-aortic roots gradually dilated, we started to implant autografts intraannulary, but still one valve dilated and aortic incompetence (AI) increased from grade I to II. Consequently the remaining aortic wall was wrapped around the new root and the composite subsequently was reinforced by a circular absorbable mesh. In addition, the aorta and pulmonary valve were exactly sized and the aortic root was reduced by commissuroplasty stitches up to 6 mm in diameter in seven cases. The ventricular size decreased in all patients 10 days after surgery, the left ventricular end-diastolic diameters (LVEDD) from 58 +/- 12 to 52 +/- 10 mm (P = 0.0002; paired t-test) and left ventricular end-systolic diameter (LVESD) from 41 +/- 12 to 36 +/- 10 mm (P = 0.008), but the contractility did not change significantly (fractional shortening from 31 +/- 9% to 30 +/- 9%). The diameter of the new aortic ring increased for the supraannular position but size matching and the intraannular valve position reduced the new ring size significantly (P = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1993

Exercise chronotropy in patients with normal and impaired sinus node function after cardiac transplantation.

The chronotropic response during graded, symptom limited exercise was investigated in 32 cardiac transplant recipients a mean of 49 +/- 18 days after transplantation. All patients had systematic evaluation of postoperative donor sinus node (SN) function and the cardioacceleratory response was compared according to the SN function. Twenty-one patients had normal postoperative SN studies (corrected SN recovery time < 520 msec, group I) while the SN function was impaired postoperatively in the remainder (n = 11, group II; corrected SN recovery time 4,149 +/- 6,283 msec in 5 patients, junctional escape rhythm in 6 patients). All patients had regained sinus rhythm at time of the exercise test. Patients in group II had lower basal sinus rates at the beginning of exercise (91.5 +/- 11 vs 101.4 +/- 7 beats/min, P < 0.02). This lower chronotropy was maintained over every incremental step (F rate between groups = 30, P = 0.0001, F rate vs workload = 15, P = 0.0001 by two-way ANOVA) and resulted in a significantly lower heart rate at individual peak exercise (108.3 +/- 20 vs 124.2 +/- 13 beats/min, P < 0.02). A total of 14/16 patients in group I but only 2/16 patients in group II accomplished a peak heart rate > or = 120 beats/min (P = 0.009). The workload achieved did not differ between the groups (107 +/- 29 vs 102 +/- 32 watts, P > 0.5). These data show a lower SN chronotropy during rest and at peak exercise in cardiac transplant recipients with postoperative SN deficiency and apparent normalization of SN function.

Adult↗
PubMed1993

[Surgical treatment of Bland-White-Garland syndrome in infants and children: experiences with revascularization techniques].

In comparison with the older technique of ligation of the anomalous coronary artery in Bland-White-Garland syndrome, the various methods of revascularisation have in common the concept of a two coronary artery system. Between 1980 and 1992, 10 children from 6 weeks to 11 years of age (mean 2 years) underwent revascularisation: direct reimplantation of the coronary ostium from the pulmonary artery to the aorta (n = 7), modified implantation with coronary artery elongation (n = 1), bypasses using subclavian artery (n = 1) or the mammary artery (n = 1). Postoperatively, 2 infants died, both following direct reimplantation, resulting in an overall mortality of 20%. There was no late death. All children but one are asymptomatic and do not require medication on follow up for between 3 months and 12 years (mean 5 years) after the procedure. Echocardiography, cardiac catheterisation, and scintigraphy show a significant improvement of left ventricular function and, as a direct consequence, a decrease in preexisting mitral insufficiency. Hence any surgical manipulation at the mitral valve should be avoided at the initial operation. As a principle, the revascularisation procedure should be performed at the earliest possible time to avoid further ischemic myocardial damage. On long-term follow-up, ventricular function and prognosis of the residual low-degree mitral insufficiency remain unclear and require regular control examinations.

Anastomosis, Surgical↗
PubMed1992

The use of mesh-tube-constricted dilated or varicose veins as arterial bypass conduit.

In general, dilated and varicose veins are not used as arterial bypass grafts despite their physiological endothelial lining. A uniform small diameter may be achieved by inserting such veins into mesh tubes. To test the degree to which dilated veins can be constricted without forming folds, in-vitro and experimental investigations were performed before such composites were used for clinical reconstructive surgery. Ovine jugular veins with a diameter of 15 mm were inserted into 6 mm tubes. After casting in paraffin wax none of the specimens showed folds on the flow surface. In 12 sheep pairs of mesh-constricted jugular veins and native femoral veins were implanted as femoropopliteal bypass grafts. Six animals were killed at 6 months and 6 at one year. All bypasses remained patent and none showed signs of obstruction caused by folds or anastomotic hyperplasia at angiographic control. Intimal hyperplasia was significantly reduced from 416 +/- 143 microns in the midportion of native vein grafts to 231 +/- 76 microns (p = 0.0001 paired t-test) in constricted veins as well as at the anastomoses (358 +/- 256 microns vs. 180 +/- 73 microns; p = 0.008). Partially or totally mesh-tube-constricted varicose veins were used for infrainguinal reconstructions in 19 patients and for coronary revascularization in 3. All grafts showed an even calibration at control angiography. As constriction does not lead to internal folds, varicose or dilated veins may be used successfully as bypass grafts after insertion into mesh tubes. The external reinforcement reduces the intimal hyperplasia within the graft and also reduces anastomotic hyperplasia.

Aged↗
PubMed1992

Long-term intrinsic pacemaker function in patients paced for sinus node deficiency after cardiac transplantation.

Fifteen cardiac transplant recipients requiring permanent pacing (AAI, n = 9; VVI, n = 6; rate responsive devices, n = 11) for postoperative sinus node (SN) insufficiency underwent evaluation of long-term SN function 240 to 1,461 days after transplantation. The intrinsic rhythm at the time of discharge was sinus in 7 patients; junctional escape in 6 patients; and pacemaker dependent in 2 patients. At follow-up, 5 patients had regained regular sinus rhythm, accounting for a total of 11 patients in sinus rhythm while 4 patients were in junctional bradycardia. The SN recovery time as determined by the permanent pacemaker was normal (< 1,500 msec) in only 1/8 patients in whom it was determined, although 4 of these 8 patients were temporarily overriding the pacemaker during ambulatory monitoring. Patients with pathological SN recovery times included 3 patients with late return of sinus rhythm and 4 patients who had recovered normal sinus rhythm before their discharge from the hospital. Three patients developed late symptoms despite apparent early normalization and underwent delayed pacemaker implantations on postoperative days 35, 52, and 225, respectively. We conclude that, in patients requiring pacemaker implantation after cardiac transplantation, normalization of SN function cannot be inferred from just return of sinus rhythm, regardless of whether it occurs early or late. These findings may have implications when a pacemaker exchange or explantation is being considered.

Electrocardiography↗