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Biomedical subjects

G Laufer

Publications and source records attributed to G Laufer.

At least 91 records · Page 5Linked to original sources
PubMed1998

Benign prognosis of early sinus node dysfunction after orthotopic cardiac transplantation.

Previous reports raised concern about the prognosis of patients with sinus node (SN) dysfunction after cardiac transplantation and led to a low threshold for permanent pacemaker (PM) placement at most institutions. The present study addresses the survival in patients with normal and impaired post operative SN function and the effect of permanent pacing with respect to overall and cardiac mortality. There were 120 patients with normal (corrected SN recovery time < 520 ms, group I) and 47 patients with imparied SN function (corrected SN recovery time > 520 ms and/or sinus arrest +/- escape rhythms). Pacing support was deemed unnecessary in 23 of 47 patients with SN dysfunction (group II; asymptomatic SN bradycardia and corrected SN recovery time 3,812 +/- 5,800 ms) while a total of 24 patients had PM placement a mean of 29 +/- 44 days after transplantation (symptomatic bradycardia or absence of sinus rhythm at discharge, group III). Patients were followed for a mean of 46.7 months. Thirty-five deaths occurred during the study period. Sixteen deaths were cardiac but none were causally related to the SN dysfunction (graft failure due to rejection or atheropathy n = 14; myocardial infarction n = 2). Four of these cardiac deaths were sudden and all occurred in the presence of widespread structural abnormalities (rejection/vasculopathy/myocardial infarction). SN dysfunction was not related to overall (P = 0.25) or cardiac mortality (P = 0.33). Regarding either endpoint, patients who had permanent PM placement did no better than their unpaced counterparts in group II (P = 0.53 and P = 0.33, overall and cardiac mortality, respectively). Likewise, survival did not differ between groups I and III for either endpoint (P = 0.77, P = 0.65, respectively). These data suggest that patients with mild SN abnormality, who are in sinus rhythm at the time of discharge, can be followed by observation without specific therapy.

Adult↗
PubMed1998

Acidic glycoproteins accumulate in calcified areas of bioprosthetic tissue.

BACKGROUND AND AIMS OF THE STUDY: This study was performed to evaluate the role of collagen fibrils, cellular elements and matrix proteins in calcification of glutaraldehyde (GA)-fixed bioprosthetic material. METHODS: Lyoplant (lyophilized bovine pericardium, type I collagen) was processed according to three protocols. DF-group (double fixation): after conventional fixation in GA (0.5% for 72 h; storage 0.25%) Lyoplant was implanted subcutaneously into rats for 5 days. Specimens were explanted and re-fixed (conventional fixation), followed by autologous or homologous reimplantation in rats for 21 or 63 days. CF-group (conventional fixation): Lyoplant patches were conventionally fixed (as DF-group), kept in 0.9% saline for one week, and then autologously and homologously reimplanted. GF-group (high-concentration GA): Lyoplant patches were processed (as GF-group) but 0.5% GA was used for tissue storage. Explanted specimens were studied by light microscopic histochemistry; calcium contents were measured by atomic absorption spectroscopy. RESULTS: Severe calcification occurred in the DF-group without differences between autologous and homologous reimplantation. In CF- and GF-groups, calcification was negligible, but immunologic response against homologous implants was accompanied by increased calcium content. Histologic characterization of matrix material in calcified areas revealed oxyphilic glycoproteins, identified as sialoglycans. CONCLUSIONS: Modification of extracellular matrix by GA is assumed as essential to cause calcification of bioprosthetic material. Calcium deposition and accumulation of sialoglycans are simultaneous events. A specific role of this glycoprotein for calcification has to be considered.

Analysis of Variance↗
PubMed1997

Simultaneous heart and kidney transplantation as treatment for end-stage heart and kidney failure.

BACKGROUND: The aim of the present analysis was to define the role of simultaneous heart and kidney transplantation (HNTX) using organs from the same donor by evaluation of clinical strategy and achieved outcome compared with a reference group of concurrently single heart transplant (HTX) and kidney transplant (NTX) recipients. Compared with other organ combinations (pancreas-kidney, heart-lung), HNTX has been performed infrequently and is reported mainly as case records in the literature. Because of expansion of recipient selection criteria for HTX and NTX, the number of patients requiring simultaneous replacement of both organs is increasing. METHODS: Six HNTX recipients, three of them suffering from long-standing type I diabetes, received transplants between September 1990 and March 1996 and were analyzed in terms of clinical and immunological demographics and outcome. They were compared with 379 HTX and 769 NTX recipients operated upon within this period. RESULTS: Survival for HNTX is 100% with a mean follow-up of 32.7+/-21.1 months. Cold ischemic time of the kidney was significantly shorter for HNTX than for NTX (6.5+/-1.0 hr vs. 22.1+/-6.8 hr, P<0.005). Although HNTX patients received HLA-unmatched grafts, no rejection of the kidney has been observed to date. There was no difference for rejection of the heart in HNTX compared to HTX recipients. CONCLUSIONS: Satisfying results are obtained by HNTX and justify the use of two organs for one recipient. The favorable immunological behavior of the kidney despite use of HLA-unmatched grafts is most probably explained by higher immunosuppression and short cold ischemic time, although a combination effect cannot be excluded.

Adult↗
PubMed1997

Emergency aortic valve replacement for critical aortic stenosis. A lifesaving treatment for patients with cardiogenic shock and multiple organ failure.

OBJECTIVE: To demonstrate that emergency aortic valve replacement can be successfully performed in patients with critical aortic stenosis and reduced left ventricular function even in cardiogenic shock with associated severe multiple organ failure. DESIGN: Retrospective, consecutive case series. SETTING: Multidisciplinary intensive care unit of a tertiary care university hospital. PATIENTS: Five patients admitted to the intensive care unit with critical aortic stenosis (aortic valve area 0.56 +/- 0.13 cm2) and greatly reduced left ventricular ejection fraction (20 +/- 3%) in prolonged cardiogenic shock and associated multiple organ failure (Multiple organ failure score 6.8 +/- 0.5; Acute Physiology, Age, and Chronic Health Evaluation III score 91 +/- 27). INTERVENTION: Emergency aortic valve replacement. RESULTS: All patients survived with full recovery of organ function. At follow-up (18 +/- 10 months) all patients were in New York Heart Association functional class I or II with improvement of left ventricular ejection fraction to 48 +/- 25%. CONCLUSIONS: This excellent outcome suggests that emergency aortic valve replacement should be strongly considered in patients with critical aortic stenosis even in cardiogenic shock and multiple organ failure.

Adult↗
PubMed1997

Surgical treatment of aortic arch aneurysms in profound hypothermia and circulatory arrest.

BACKGROUND: This study was undertaken to define the factors that influence mortality rate and neurologic outcome after repair of the aortic arch and various portions of the thoracic aorta in patients with profound hypothermia and circulatory arrest. METHODS: Between November 1986 and January 1996, 105 patients were treated surgically for aortic disease involving the transverse aortic arch. Profound hypothermic circulatory arrest and selective brachiocephalic perfusion was used in all patients. In 19 patients retrograde cerebral perfusion was instituted during the period of circulatory arrest. Independent predictors for 30-day mortality and permanent neurologic deficits were evaluated by multiple logistic regression. RESULTS: Thirty-day mortality for the entire group was 19% (20/105); 21.2% for urgent versus 15.4% for elective cases, respectively. Statistical analysis showed that age is the most important factor that significantly influences mortality rate (p < 0.0145) and neurologic outcome (p < 0.006). Variables such as circulatory arrest time (p < 0.24), previous cardiac or aortic operations (p < 0.19), and sex (p < 0.55) failed to show any influence on mortality rate. Permanent neurologic deficits were diagnosed in 12.9% (11/85) of the patients. CONCLUSIONS: The incidence of permanent neurologic dysfunction as well as the mortality rate are predominantly related to the age of the patient. In this patient group, statistical analysis failed to show a direct correlation between duration of circulatory interruption and neurologic outcome.

Adolescent↗
PubMed1997

The use of profound hypothermia and circulatory arrest in operations on the thoracic aorta.

OBJECTIVE: This retrospective study reviews the contemporary surgical outcome of our patients undergoing operations on thoracic aneurysms in deep hypothermic circulatory arrest. METHODS: Between January 1989 and February 1995, 279 patients were operated on in our institution on various portions of the aorta. In 143 patients (97 male, 46 female), deep hypothermia and circulatory arrest were used as the standard operative technique. Patients age ranged from 16 to 83 years (mean 55). Final indication for operation was dissection Type A in 80 patients (61 acute, 19 chronic), dissection Type B in 21 patients (17 acute, 4 chronic) and atherosclerotic aneurysms in 42 patients (11 acute, 31 chronic). 16 patients were operated under preoperative unstable hemodynamic conditions, 6 patients had been resuscitated preoperatively. Surgical technique included cardiopulmonary bypass with femoral artery cannulation. For added cerebral protection all patients received Cortisone and barbiturates right before circulatory arrest (confirmed by 0-EEG). The segment of the aorta containing the area with the aneurysm, was resected and replaced with a tubular albumin coated graft. RESULTS: The 30-day mortality was 31.15% (19/61) in the acute and 23.52% (4/19) in the chronic type A dissection group, 35.29% (6/17) in the acute and 25% (1/4) in the chronic type B group, 36.3% (4/11) in the acute and 22.58% (7/31) in the chronic atherosclerotic group. Causes of postoperative death in order of frequency were: multiorgan failure (n = 15), myocardial failure (n = 13), bleeding (n = 4), sepsis (n = 4), myocardial infarction (n = 3) and stroke (n = 2). CONCLUSION: Despite rather high mortality rates in the acute aneurysm groups, the technique of profound hypothermic circulatory arrest represents a relatively safe method for operations on the thoracic aorta.

Adolescent↗
PubMed1997

Increased pulmonary flow velocities in oversized homografts in patients after the Ross procedure.

OBJECTIVE: Between September 1991 and July 1996, 60 patients (mean age 29.8 +/- 9 years; range 5-57) underwent aortic root replacement with pulmonary autograft, a viable biologic and nondegenerating substitute. The pulmonary root was replaced with cryopreserved homografts from cardiac transplant recipients. The aim of this study was to evaluate differences in early valve function of viable and cryopreserved allografts. METHODS: All patients had Doppler echocardiographic examinations preoperatively, at discharge from hospital and 54 patients at 1 year follow-up. We measured aortic and pulmonary peak flow velocities with continuous and pulsed-wave Doppler, and graded aortic and pulmonary insufficiency (AI, PI) with color Doppler flow (grade 0-IV). Intraoperatively, the diameters of the pulmonary root and the pulmonary homograft were measured with standard valve probes and matched to body surface area. RESULTS: Pulmonary peak flow velocity (PVmax) increased significantly from preoperative 0.87 +/- 0.11 m/s to 1.30 +/- 0.34 m/s postoperatively (P < 0.001). The implanted homografts (mean 25.9 +/- 2.4 mm) were larger than their native pulmonary diameter (mean 23.3 +/- 1.8 mm) in all patients. Homograft size matched for body surface area (BSA) did not correlate with increased PVmax. There was a significant increase of PVmax at follow-up (FU) since discharge, also (1.83 +/- 0.53 m/s; P < 0.001). Pulsed-wave Doppler demonstrates that increase of PVmax is located directly at the homograft leaflets and not at the anastomoses. Aortic peak flow velocities (AVmax) were normal postoperatively and at FU (post = 1.35 +/- 0.35 m/s; FU = 1.17 +/- 0.27 m/s). There was no significant change in AI or PI since discharge (AI FU = 0.8 +/- 0.4; PI FU = 0.7 +/- 0.5). Eight patients with fever and symptoms diagnosed as post-pericardiotomy syndrome had significantly higher PVmax at FU (PVmax = 2.41 +/- 0.40 m/s; P < 0.02). CONCLUSIONS: The Ross procedure leads to normal AVmax but significant increase of PVmax even in oversized cryopreserved homografts immediately after surgery. Further increase of PVmax without changes in AVmax in the first year demonstrates that changes in flow velocities are valve related and not due to increase in cardiac output. Further investigations will be necessary to determine whether this observation is due to valve rejection or early leaflet degeneration and treatment with immunosuppressive therapy is warranted.

Adult↗
PubMed1997

Prostaglandin E1--bridge to cardiac transplantation. Technique, dosage, results.

BACKGROUND: Heart transplantation candidates who remain severely symptomatic despite therapy are normally hospitalized. Continuous infusion of intravenous drugs from a portable pump may allow such patients to live a fairly active life until a donor heart is found. AIM: To investigate in an open pilot study if heart transplantation can be safely accomplished if these patients are continuously bridged with various regimens including inotropic support with low-dose dobutamine in conjunction with dopamine and prostaglandin E1. METHODS: We report on 5 years' experience with prostaglandin E1, a potent vasodilator with proven efficacy in severe heart failure when coupled with catecholamines. From 1990 to 1995 54 heart transplantation candidates were bridged with prostaglandin E1 in addition to dobutamine 5 micrograms.kg-1. min-1 and dopamine 3 micrograms.kg-1 min-1 (group A; n = 32) or in addition to 3 micrograms.kg-1 min-1 dopamine alone (group B; n = 22), and 11 heart transplantation candidates were bridged with dobutamine 5 micrograms.kg-1. min-1 and dopamine 3 micrograms.kg-1 min-1 only (group C; n = 11). In an initial dose-ranging test, prostaglandin E1 was uptitrated to side effect limit (29 +/- 1 ng.kg-1.min-1). Haemodynamics, except for stroke volume index, were similar in all patients at baseline and a sufficient haemodynamic response (20% increase in stroke volume) was observed during the acute study. Fifty percent of the peak dose was used for initiating chronic therapy; the dose of prostaglandin E1 was further reduced if side effects recurred. RESULTS: Twenty-nine (54%) patients in groups A and B and six in group C could be discharged home with chronic therapy via a Hickman catheter connected to a portable pump. After 4 weeks in six patients in group A and in 13 patients in group B, when prostaglandin E1 had been reduced from 15 +/- 2 ng.kg-1.min-1 to 8 +/- 1 ng.kg-1 min-1 increases in cardiac index and decreases in systemic vascular resistance were sustained, and a permanent decrease in pulmonary vascular resistance index was observed in group B. Intravenous therapy was changed in nine patients (3/1/5) because of side effects and worsening heart failure. Prostaglandin E1 was withdrawn in three of these patients because of an increase in serum creatinine (3 mg.100 ml-1), and in one because of noncompliance. In total, there were 17 cardiac deaths (9/6/2), 42 heart transplants (22/14/6) and six (1/2/3) weaned survivors (including one non-cardiac death) in this study. Overall outcome was similar in groups A and B, but distribution after 2 months appeared to be different (P < 0.05) based on more transplantations in group A. CONCLUSION: We concluded that chronic infusions with prostaglandin E1 at reduced dosages is a feasible and safe therapeutic adjunct to bridge end-stage heart failure patients and may yield desirable effects in a subset of patients in the absence of inotropic support by dobutamine.

Alprostadil↗
PubMed1997

PR interval adaptation in the denervated transplanted heart.

In the present study, the dynamic PR response upon standardized treadmill exercise was investigated in 21 transplant recipients (recipient age 48 +/- 17 years, donor age 31 +/- 12 years, > 1 year after transplantation). HR and PR interval were measured at rest and at the end of each 25-W increase in workload till peak exercise. In 17 cases norepinephrine (NE) was assessed at rest, and at the end of each workload the HR increased from 99.3 +/- 14 to 143.4 +/- 25 beats/min at individual peak exercise, and NE increased from 1,307 +/- 1,163 to 3,688 +/- 2,036 pg/mL, while the PR interval shortened from 149.2 +/- 13 to 119.3 +/- 20 ms. On average, PR decreased by 3.4 ms for a 10-beat increase in HR, and the HR-PR interval relationship was described by a linear regression (y = 176.8-0.3469x, P = 0.0001). One patient who was unable to increase his NE levels upon exercise showed virtually no decrease in the PR interval and no HR increase. Both recipient age and donor age were moderately and significantly related to the minimum PR interval achieved at peak exercise (r = 0.6, P = 0.008 and r = 0.51. P = 0.049, respectively). These data show the following: (1) adaptation of the PH interval upon exercise does occur in the denervated transplanted heart; (2) the HR-PR relation is similar to that reported in the innervated heart; (3) the overall decline in PR interval is blunted, since denervated patients start at shorter resting PR intervals and achieve relatively longer PR intervals at peak exercise when compared to their innervated counterparts; (4) these exercise induced changes of the PR interval may be explained by circulating NE; and (5) NE levels achieved at peak exercise and the sensitivity of the AV node to NE seem to be age related.

Adaptation, Physiological↗
PubMed1997

Antifibrinolytic properties of the vascular wall. Dependence on the history of smooth muscle cell doublings in vitro and in vivo.

Increased expression of plasminogen activator inhibitor-1 (PAI-1) mRNA in atherosclerotic human arteries suggests a linkage between PAI-1 gene expression and cellular proliferation, the fundamental feature of atherosclerosis. To investigate whether smooth muscle cell (SMC) proliferation influences overall fibrinolytic properties of the vascular wall, we examined the effect of serial in vitro passaging of human SMCs on tissue plasminogen activator (TPA) and PAI-1 synthesis levels as well as the ability to modulate TPA and PAI-1 synthesis of human umbilical vein endothelial cells (HUVECs). As in vivo correlates for such late-passage cells in culture, SMCs derived from human atherosclerotic plaques were used, because they are thought to have already undergone numerous cell doublings. We observed an increase of PAI-1 secretion (from 591 +/- 106 to 2952 +/- 290 ng PAI-1.10(5) cells-1.24 h-1) with a concomitant fourfold to fivefold increase of PAI-1 mRNA levels, as well as a decrease of TPA secretion (from 118 +/- 34 to 8 +/- 1.3 ng TPA.10(5) cells-1.24 h-1) and a twofold to threefold decrease of TPA mRNA levels with increasing in vitro passage number (from passage 3 to 11) of normal pulmonary artery smooth muscle cells (PASMCs) (P < .05). SMCs derived from atherosclerotic plaques of coronary arteries (CASMCs) displayed higher levels of PAI-1 antigen synthesis (3093 +/- 507 ng PAI-1.10(5) cells-1.24 h-1) with an approximately twofold increase of PAI-1 mRNA levels, as well as decreased levels of TPA antigen synthesis (10 +/- 1.6 ng TPA.10(5) cells-1.24 h-1) with an approximately 1.5- to 2-fold decrease of TPA mRNA levels in passage 1, compared with their counterparts derived from normal-appearing arterial tissue of the same vessel (1794 +/- 525 ng PAI-1.10(5) cells-1.24 h-1; 17 +/- 5 ng TPA.10(5) cells-1.24 h-1) (P < .001; P < .01). Incubation of HUVEC cultures with the 24-hour conditioned media (CM) of early-passage PASMCs decreased endothelial PAI-1 antigen synthesis by approximately 42% (P < .001) and endothelial PAI-1 mRNA levels about twofold to threefold (P < .001), whereas by incubation with the 24-hour CM of late-passage PASMCs, endothelial PAI-1 antigen synthesis was upregulated by 68% (P = .001), with a concomitant twofold increase of endothelial PAI-1 mRNA levels (P < .001). The apparent MW of this heat- and acid-stable PAI-1 upregulating factor appears to be between 50 and 100 kD, as judged by ultrafiltration. Incubation of HUVEC cultures with the 24-hour CM of early-passage CASMCs derived from normal-appearing arterial tissue showed no significant influence on endothelial PAI-1 synthesis, whereas incubation with late-passage normal CASMCs, as well as early-passage atherosclerotic CASMCs from the same vessel, increased endothelial PAI-1 antigen secretion by 45% and 48% (P < .001), with a concomitant 1.5 fold to 2-fold increase of endothelial PAI-1 mRNA levels (P < .05). No significant change in endothelial TPA synthesis was observed by incubation with CM of either PASMCs (early or late passage) or CASMCs (atherosclerotic or normal). These data suggest that SMC proliferation is associated with (1) increased SMC PAI-1 synthesis as well as decreased TPA synthesis and (2) upregulation of endothelial PAI-1 synthesis by SMC CM. This phenomenon is observed with either late passages of normal PASMCs and CASMCs or early passages of atherosclerotic plaque CASMCs. This suggests that proliferating SMCs are a major regulator of the fibrinolytic potential within the vessel wall, thereby contributing to the thrombotic risk associated with the development of atherosclerosis.

Arteriosclerosis↗
PubMed1997

Prostaglandin E1 infusion compared with prostacyclin infusion in patients with refractory heart failure: effects on hemodynamics and neurohumoral variables.

Prostaglandin E1 or prostacyclin were randomly infused in 18 patients with severe chronic heart failure who did not respond to oral treatment. Maximally tolerated dosages of both agents increased cardiac index; however, only prostacyclin decreased mean arterial pressure and increased plasma norepinephrine significantly. Twelve hours after 50% peak dose reduction, atrial natriuretic peptide levels, right atrial pressure, mean pulmonary artery pressure, and mean arterial pressure continued to decrease with prostaglandin E1, whereas the increase in cardiac index was sustained; in contrast, at 50% prostacyclin dose reduction, cardiac index decreased toward baseline, suggesting that, with reduced dosages for chronic infusions, desired hemodynamic changes seem to be sustained with prostaglandin E1 only.

Alprostadil↗
PubMed1996

Cyclosporine may affect improvement of cognitive brain function after successful cardiac transplantation.

BACKGROUND: The effects of cardiac transplantation on cognitive brain function are uncertain. METHODS AND RESULTS: We measured cognitive brain function and quality of life in out-of-hospital cardiac transplant candidates (n = 55; ejection fraction, 19.9%; age, 54.8 years [means]). After transplantation, the patients were serially reevaluated at 4 months (n = 25) and at 12 months (n = 19). Brain function was measured objectively by cognitive P300 evoked potentials. Additionally, standard psychometric tests (Trail Making Test A, Mini-Mental State Examination, and Profile of Mood State test) were performed. Cognitive P300 evoked potentials were impaired in cardiac transplant candidates (359 ms, recorded at vertex) compared with 55 age- and sex-matched healthy subjects (345 ms, P < .01). Trail Making Test A was also abnormal (45 versus 31 seconds in 55 healthy subjects, P < .01). After transplantation, P300 measures were normalized at 4 months (345 ms, P < .05 versus before transplantation) but declined again at 12 months (352 ms, P = NS versus before transplantation). Stepwise multiple regression analysis revealed that cumulative cyclosporine dosage was the only predictor of individual cognitive brain function 4 months (753 mg/kg body wt, P < .05) and 12 months (2006 mg/kg body wt, P < .01) after transplantation, respectively. CONCLUSIONS: Objective cognitive P300 auditory evoked potential measurements indicate that cognitive brain function is significantly impaired in patients suffering from stable end-stage heart failure. Successful cardiac transplantation is effective to fully normalize impaired brain function. Subsequent relative long-term decline of cognitive brain function after successful cardiac transplantation is strongly suggested to be related to cumulative cyclosporine neurotoxicity.

Affect↗
PubMed1996

Decrease in pacemaker incidence after orthotopic heart transplantation.

A decrease in sinus node dysfunction and pacemaker requirement after orthotopic heart transplantation was observed over a 6.5-year period, probably indicating the effect of a learning curve. Indirect evidence suggests a traumatic genesis of sinus node dysfunction after cardiac transplantation.

Arrhythmia, Sinus↗
PubMed1996

The importance of the effect of underlying disease on rejection outcomes following orthotopic liver transplantation.

Despite major advances in immunopharmacology, virtually all patients receive the same center-specific immunosuppressive regimen following orthotopic liver transplantation (OLT). The present analysis was performed on the hypothesis that the original disease representing the indication for OLT leads to a different initial immunological situation of the patient. The type of original disease might therefore be a predisposing factor for acute rejection episodes and influence graft and patient survival. From January 1988 to July 1994, 34 patients received OLT at our institution for end-stage primary biliary cirrhosis (group 1) and 66 patients for end-stage alcoholic cirrhosis (group 2). Overall survivals at 1 and 5 years in group 1 versus group 2 were 67% versus 80% and 50% versus 68%, respectively (P<0.04). Retransplantation was performed in 21% of patients from group 1 and in 6% from group 2. The estimated risk for freedom from acute rejection amounts to 38% in group 1 compared with 59% in group 2 (P<0.02). Multivariate regression analysis of potential risk factors identified only the underlying disease as independent predictor. Analysis of cumulative rates of clinically relevant rejection episodes stratified by group revealed 0.29 and 0.05 episodes per patient at one month and 0.80 and 0.06 at six months (P<0.009) respectively. In our clinical experience it was possible to confirm the hypothesis that the underlying disease is the reason for a significantly different incidence of acute rejection episodes and that it subsequently influences graft and patient survival. This approach to an individually adapted immunosuppressive therapy should be taken into consideration and other appropriate parameters investigated.

Acute Disease↗
PubMed1996

Implantation of a unipolar cardioverter/defibrillator system under local anaesthesia.

OBJECTIVE: To evaluate prospectively the safety and feasibility of the implantation of cardioverter/defibrillator systems under local anaesthesia. Conventionally, cardioverter/defibrillator systems are implanted under general anaesthesia. With the development of single-lead transvenous unipolar cardioverter/defibrillator systems for subpectoral implantation a pacemaker-like approach for device implantation appears applicable. METHODS: Implantation of a single-lead transvenous unipolar cardioverter/defibrillator under local anaesthesia with sedation for defibrillation threshold testing was performed in 37 consecutive patients. The presenting arrhythmia was ventricular fibrillation in 13 patients, and monomorphic ventricular tachycardia in 24 patients. A 1% lidocaine solution was used for local anaesthesia, and midazolam was applied for sedation to perform defibrillation threshold testing. Arterial blood pressure, arterial oxygen saturation and heart rate were monitored throughout the procedure. The patient's tolerance of the implantation procedure was evaluated with a standardized questionnaire. RESULTS: The unipolar transvenous cardioverter/defibrillator system was implanted successfully in all patients under local anaesthesia. During defibrillation threshold testing, sufficient sedation was achieved with 12.5 +/- 3.7 mg midazolam. For determination of the defibrillation threshold 5.9 +/- 1.4 episodes of ventricular fibrillation were induced. The mean defibrillation threshold was 13.1 +/- 5.5 J, and the mean duration of the implantation procedure was 68 +/- 30 min. Mean heart rate, mean arterial blood pressure and arterial oxygen saturation were not significantly different before and after defibrillation threshold testing. Twenty-six patients (70%) were symptom-free throughout the implantation procedure; most of the remaining patients reported minor symptoms. There were no complications, and patients were discharged 2.2 +/- 0.7 days after implantation. In 12 patients, post-implant testing of the implantable cardioverter/defibrillators was performed successfully, without sedation, 2.8 +/- 1.4 days after as an outpatient procedure. CONCLUSION: Single-lead unipolar transvenous implantable cardioverter/defibrillator systems can be safely implanted under local anaesthesia with mild sedation for defibrillation threshold testing. The procedure is well tolerated.

Aged↗
PubMed1996

Operative management of aortic arch aneurysm using profound hypothermia and circulatory arrest.

Since the first successful replacement of the aortic arch with perfusion of the head, various methods have been employed to preserve cerebral function during aneurysm operations. Although deep hypothermia was used for surgery of the aortic arch, as early as 1963, the introduction of prolonged circulatory arrest has simplified replacements of the aortic arch. Between October 1990 and September 1993, 69 patients underwent aortic arch replacement for aneurysmal disease at the Dept. of Cardio-Thoracic Surg., University of Vienna. 52 patients had an acute dissection Type A, 17 patients were operated on electively. The patients age (48 male, 21 female) ranged between 16 and 81 years. Primary diagnosis was hypertension (n=44), marfan (n=14), unknown (n=10) and trauma (n=1). Total cardiopulmonary bypass was established via femoral artery cannulation. All patients received Cortison and Thiopental for added cerebral protection. Deep hypothermia (12 degrees C), confirmed by 0-EEG, and circulatory arrest were induced in all patients. The aneurysm was opened longitudinally and a full thickness single patch or "island" of aortic wall, containing the origins of the three arch vessels, was constructed and anastomosed in a continuous fashion to an albumin coated graft. 68 patients survived the operation (intraoperative mortality 1%). The 30-day mortality was 23% (n=16). Twelve patients died of multiorgan failure, two patients of a stroke and two due to myocardial infarction. The mean cerebral circulatory arrest time was 32 minutes (range 11-61 min.). Our experience with aortic arch replacements using profound hypothermia and circulatory arrest supports our contention, that it is the method of choice in this very difficult surgical field.

Adolescent↗