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Biomedical subjects

W Konertz

Publications and source records attributed to W Konertz.

At least 73 records · Page 4Linked to original sources
PubMed1996

Hemodynamic performance of the PRIMA Edwards stentless aortic xenograft: early results of a multicenter clinical trial.

Between June 1991 and July 1993, 200 PRIMA Edwards stentless aortic bioprostheses were implanted in 4 European centres. Mean age of the group was 68.5 years (S.D. 8.0). The subcoronary implantation technique was used in 161 patients, the inclusion cylinder technique in 39 patients. Valve diameters ranged from 19 mm to 29 mm. Transthoracic Doppler echocardiographic studies were performed at discharge, and after 6 months and 12 months; a complete one-year follow-up was obtained. At 12 months peak systolic gradients ranged from 35.2 mmHg (19 mm valve) to 10.9 mmHg (29 mm valve) and effective orifice area ranged from 0.8 cm2 (19 mm valve) to 2.8 cm2 (29 mm valve). 30-day mortality was 3%, 12-month mortality was 5%. Complications were thrombo-embolism in six patients (3%), haemorrhage in three patients (1.5%), endocarditis in two patients (1%), and total AV-block requiring an endocavitary pacemaker in 14 patients (7%). At one year aortic regurgitation was evident in 27% patients but only one patient showed grade III. The stentless xenograft still offers good hemodynamics at one year. Morbidity and mortality are acceptable. Evaluation of the long-term performance of this new type of xenograft will be an important issue in future.

Adult↗
PubMed1996

Surgical preconditioning and completion of total cavopulmonary connection by interventional cardiac catheterisation: a new concept.

A new, staged procedure for univentricular repair of "high risk" patients using a combined surgical transcatheter technique is reported. As first step a surgical hemifontan procedure was performed and a multifenestrated patch inserted into the right atrium. For later transcatheter completion of univentricular repair, a subtotal banding just above the cavoatrial junction was performed. Two months later transcatheter completion was performed by balloon dilatation of the banded cavo-atrial junction and additionally either by inserting a covered stent as intracardiac conduit between the superior and inferior vena cava or by inserting a (non-covered) stent into the cavo-atrial junction and occluding the fenestrations in the right atrial patch using Rashkind-PDA occluders. This new technique was successfully applied without mortality in eight patients with a preoperative mean pulmonary pressure of 18 to 23 mm Hg. No complications typical for Fontan-like corrections occurred within the follow up period of 4 to 14 months.

Adolescent↗
PubMed1996

[Percutaneous "high risk" angioplasty with prophylactic cardiopulmonary support. High risk PTCA with mechanical circulatory support].

With improved technology and development of several mechanical assist devices, the indications of percutaneous transluminal coronary revascularization have been extended. In 39 patients (30 men, mean age = 60.1 +/- 8.1 years) with angina pectoris or heart failure, with poor operative risk-benefit ratio and ejection fraction < 35% and/or target vessel supplying > 50% of the viable myocardium, we performed assisted percutaneous transluminal coronary revascularization. Intraortic balloon counterpulsation (n = 16), extracorporal circulation (n = 21), or hemopump (n = 2) were used for mechanical support. Complete 6-week follow up was possible in 27 patients. An improvement of left-ventricular function (patients with EF < or = 35% demonstrated an improvement: 27 +/- 7 vs 36 +/- 10%, p < 0.05), heart failure (patients with EF < or = 35% demonstrated an improvement of maximal oxygen uptake: 14 +/- 4 vs 17 +/- 4 ml/kg/min; p < 0.05) and a marked improvement of angina (23/38 demonstrated CCS-improvement of at least one class) was found. Hospital mortality was as low as 2.6%. Major postinterventional complications included nonfatal myocardial infarction (n = 2), fatal retroperitoneal bleeding (n = 1), pulmonary edema (n = 1), nonfatal ventricular fibrillation (n = 1), cerebrovascular event without residual (n = 1), and deep vein thrombosis (n = 4). In conclusion, assisted percutaneous revascularization was successful in a high risk subset of patients with increased surgical risk and/or poor ventricular function.

Aged↗
PubMed1996

[Surgical coronary revascularization of the beating heart].

Despite the fact that all the progress in technology, surgical technique and pathophysiological knowledge has made aortocoronary bypass surgery a safe routine procedure, there are certain clinical settings where an alternative approach seems to be advantageous. In 50 patients with age ranging from 51 to 74 years with advanced coronary heart disease and poor left ventricular (LV) function, as well as in patients with good LV function and single or double vessel disease not amenable for PTCA and in patients with acute ischemia or recent myocardial infarction, we performed coronary artery bypass grafting (CABG) without cardioplegic arrest during a short period of left ventricular unloading by means of a left ventricular assist device (LVAD). During LVAD support we administered Esmolol to decrease the heart rate and to keep the heart flaccid to facilitate easier peripheral anastomosis on a breathing heart. Preoperative ejection fraction ranged from 15 to 56%. In two patients of the acute MI-group, we continued the left ventricular mechanical support postoperatively, one of them survived. We performed on average 1,4 distal anastomoses and used in 34 cases the left internal mammary artery. All but three patients survived the procedure in stable conditions and could leave intensive care after a mean stay of 1.5 days. There were no perioperative myocardial infarctions. In our view, CABG during LVAD support without heart lung machine and cardioplegia is a safe and life saving procedure. No ischemic damage is applied to the heart and it can be recommended for cautions use in select patients.

Adult↗
PubMed1996

[Endoventricular patch-plasty for reconstruction of ventricular geometry and pump function in myocardial aneurysm].

This report deals with the first experience with endoventricular patch plasty in patients suffering from left ventricular aneurysm. The early postoperative results in 18 patients operated upon during January and May 1995 are encouraging. All patients survived the procedure. In contrast to patients operated on according to a linear resection technique the postoperative outcome and the early results are much better with this technique. We recommend the endoventricular patch plasty on a beating heart.

Aged↗
PubMed1996

[Acute and chronic mechanical circulatory support].

Mechanical circulatory support and mechanical unloading of the left ventricle become more and more routine in clinical treatment regimens of both acute and chronic heart failure. Along with increasing availability of different cardiac assist systems one can adjust the degree of support according to the clinical situation. We report about our experience in the period between January 1994 and May 1995 with following assist systems: Hemopump, centrifugal pumps, Medos, HIAVAD and Novacor. We implanted those devices in 21 patients out of following indications: postinfarct--cardiac failure (CF), postcardiotomy CF, elective postcardiotomy support, myocarditis CF and "bridge" to transplant. Ten patients survived the period of mechanical support and could be weaned successfully. Circulatory support was sufficient in all cases, indication, time of implantation, anticoagulation and prevention of infections are discussed.

Aged↗
PubMed1996

[Orthotopic and heterotopic heart transplantation].

Orthotopic cardiac transplantation is an excellent palliation for endstage cardiac failure in select patients. Individual patients may benefit from heterotopic cardiac transplantation. Since 1986 88 patients received an orthotopic or heterotopic transplant at Charité University Hospital. 83% one year-survival and 58% nine years-survival rates were achieved. Infection is a leading cause of death in patients after cardiac transplantation. Due to persistent scarcity of donor organs we have to consider alternative surgical methods as there are dynamic cardiomyopathy, and the chronic conventional surgery, and the chronic use of mechanical circulatory assist systems.

Adolescent↗
PubMed1995

Pulmonary agenesis in a newborn: implantation of tissue expander to prevent a mediastinal shift.

Unilateral pulmonary agenesis is a rare congenital anomaly whose aetiology is not completely known. Vitamin A deficiency, viral agents, or genetic factors are discussed. The incidence was estimated at 1 in 10,000-15,000 autopsies by several authors. Associated malformations, mainly affecting the cardiovascular, gastrointestinal, and musculoskeletal system influence the prognosis of patients as does the location of the missing lung. We report the implantation of a tissue-expander in a three-months-old infant suffering from a right-sided lung agenesis associated with sinus-venosus defect. Other malformations were excluded by sonographic methods. Mediastinal shift with dextropositio cordis in compensatory emphysema of the left lung and frequent infections were the cardinal symptoms. These led to cardiopulmonary decompensation twice. The implantation of the tissue-expander was performed following an aortopexy, which was only temporarily successful. This method allows the filler to be adapted with age to the pleural volume by instillation of sterile saline solution via a microport. Whether or not thorax deformities and scoliosis will be prevented cannot be predicted exactly at this time.

Adult↗
PubMed1995

Removal of a giant cardiac fibroma from a 4-year-old child.

In an 8-month-old infant presenting with a systolic heart murmur, a cardiac tumor was diagnosed by means of 2-dimensional echocardiography, cardiac catheterization, and magnetic resonance imaging. In the following years, the child developed ventricular arrhythmias, which were controlled with antiarrhythmic drugs. The operation was undertaken when the boy was 4 years and 3 months of age. A tumor of the interventricular septum measuring 45 x 13 x 25 mm was resected in toto. The defect in the ventricular septum was closed with a Dacron patch. The postoperative course was uneventful. Histologic examination classified the tumor as a fibroma.

Blood Vessel Prosthesis↗
PubMed1994

Preliminary experience with the Toronto SPV stentless porcine bioprosthesis for aortic valve replacement.

From November 1992 to March 1993 fourteen patients received the Toronto SPV stentless porcine xenograft as aortic valve replacement. Median age was 56 years (range 32-70 years). 7 patients were male and 7 female. Implanted valve sizes ranged from 23 mm to 29 mm, the majority of patients received valves with 27 and 29 mm tissue diameter. A learning process was evident by aortic crossclamp time decreasing with experience. No valve-related mortality or morbidity occurred. Postoperatively echocardiography showed near normal valve performance in most patients. The longevity of the valve, however, still has to be established. Meanwhile we continue the implant of stentless bioprostheses as aortic valve substitutes in selected patients.

Adult↗
PubMed1994

Aortic valve replacement with cryopreserved pulmonary allograft.

Experimental as well as clinical data support the finding of using the pulmonary valve as a systemic semilunar valve. From January 1990 to December 1992, 89 patients received pulmonary cryopreserved allografts as aortic valve replacement. Sixteen subjects suffering from native or prosthetic valve endocarditis were included. Age ranged from 10 to 74 years. Sixty-five patients received isolated aortic valve replacement and 24 patients required additional surgical measures, such as coronary artery bypass graft, mitral valve reconstruction, replacement of the ascending aorta, supravalvular patch aortoplasty, ventricular septal defect closure, or myectomy. All operations were performed with normothermic bypass and cold cardioplegic arrest. Follow-up is maintained by visits to the outpatient clinic and echocardiographic assessment of the valve status every 3 months during the first year and every 6 months thereafter. There were four early and three late deaths. Four valves had to be removed: one intraoperatively and three 2, 4, and 24 months postoperatively. Echocardiographic assessment proved that gradients across the valve were low or absent. The majority of patients showed trivial or no aortic regurgitation during follow-up. No thromboembolic events have been observed and no new endocarditis occurred. Thus, event-free survival at 3 years is 87%. The results with pulmonary allografts have shown to be comparable to aortic allografts. Even in patients with acute native or prosthetic valve endocarditis, the use of cryopreserved pulmonary allografts has shown no adverse effects. We continue to implant cryopreserved pulmonary allografts in the aortic position. The long-term function of the valve, however, must be established, making continued evaluation of postoperative patients mandatory.

Adolescent↗
PubMed1993

Surgical experience with defibrillator implantation using nonthoracotomy leads.

Between October 10, 1989, and June 17, 1991, 109 patients with life-threatening ventricular arrhythmias received an implantable cardioverter-defibrillator at our institution. In 50 patients, nonthoracotomy lead systems consisting of a subcutaneous chest wall patch electrode near the cardiac apex and one (Cardiac Pacemakers, Inc: Endotak C) or two (Medtronic: Transvene) transvenous electrodes were tested. The mean ejection fraction was 0.44 +/- 0.15 with a range from 0.19 to 0.81. Twenty-four patients had a history of open heart operation. In 43 patients the nonthoracotomy lead system was implanted, whereas in 7 patients epicardial patch lead systems were required due to elevated defibrillation thresholds during nonthoracotomy lead testing. There was one perioperative death unrelated to the operative procedure (hydrocephalus internus). Hemorrhage from the subcutaneous patch pocket or the device pocket that required reintervention occurred in 4 patients. During a mean follow-up of 13 +/- 5 months (range, 4 to 26 months) no dislocation of an endocardial lead, insulation defect, or lead fracture has been observed. In 1 patient, the lead system had to be removed due to infection of the subcutaneous patch pocket. The cardiovascular survival rate was 98% at 12 and 18 months, and freedom from sudden cardiac death was 100% at 6 and 12 months. In conclusion, defibrillator implantation using nonthoracotomy lead systems is feasible with a success rate of 86%, and during short-term follow-up no problems related to the lead system such as dislocation, fracture, or insulation defect have occurred.

Adolescent↗
PubMed1993

Mechanical ventilation in the prone position for acute respiratory failure after cardiac surgery.

Ten patients with acute respiratory failure (ARF) after coronary artery bypass grafting were studied during conventional mechanical ventilation in the supine and in the prone position. Impaired gas exchange was defined as an inspired oxygen fraction (FIO2) greater than 0.5 to maintain an arterial oxygen tension (PaO2) > or = 70 mmHg, an alveolar-arterial PaO2 gradient (PA-aO2) > 200 mmHg and a venous admixture (QVA/QT) > 15% during mechanical ventilation with a tidal volume (VT) = 10 to 12 mL/kg, frequency (f) = 10 to 15 VT/min, inspiratory-expiratory (I:E) ratio = 0.5, and positive end-expiratory pressure (PEEP) of 5 to 7.5 cm H2O. In the supine position, systemic and pulmonary hemodynamics were in the normal range, but oxygenation was severely impaired. In all patients thoracic computed tomography scans were obtained and revealed crest-shaped bilateral densities in the dependent lung regions. FIO2 of 0.67 +/- 0.22 was required to maintain a PaO2 greater than 70 mmHg during mechanical ventilation in the supine position. Under these conditions PA-aO2 and QVA/QT were 362 +/- 153 mmHg and 32.5 +/- 8.3%, respectively. CO2 elimination was not severely affected. The patients were turned into the prone position after an average of 30.6 +/- 5.4 hours postoperatively and ventilated with unchanged VT, f, PEEP, and inspiratory-expiratory ratio for 26.7 +/- 11.7 hours (range, 10 to 42 hours). A second cardiopulmonary status was obtained within 2 to 5 hours of ventilation in the prone position.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗