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H H Sievers

Publications and source records attributed to H H Sievers.

At least 19 recordsLinked to original sources
PubMed1992

Truncus arteriosus communis associated with interrupted aortic arch: a report on two uncommon cases.

The paper presents two infants with the A-4 type of truncus arteriosus communis (according to Van Praagh's classification). One patient who survived a surgical procedure demonstrated a rare variant of aortic arch interruption to the left off the left subclavian artery (type A according to Celoria and Patton), whereas the second presented an uncommon anomaly in which the right subclavian artery originated from the descending aorta with associated severe truncal valve incompetency. The authors describe the clinical picture along with the surgical treatment of the first infant who being six days old was subjected to a correction employing the wide patent ductus arteriosus to reconstruct the aortic arch, following the method described by Gomes and McGoon. Subsequently an aortic homograft was implanted in order to connect the right ventricle and the pulmonary artery.

Aortic Arch Syndromes↗
PubMed1992

Performance of a stentless xenograft aortic bioprosthesis up to four years after implantation.

Conventional biologic and mechanical prostheses have important limitations with regard to their hemodynamic characteristics and long-term durability. We evaluated the hemodynamic function of a stentless porcine aortic prosthesis in 10 patients by invasive pressure measurements and angiography with videodensitometry 8 +/- 4 days after operation, as well as by Doppler echocardiography 35 +/- 15 months after valve replacement. The early postoperative invasive study revealed a mean gradient of 8 +/- 6 mm Hg across the prosthesis, no regurgitation in eight patients, and mild regurgitation, defined as less than 20% regurgitant fraction, in the remaining two patients. The late postoperative Doppler echocardiographic study revealed a mean gradient across the aortic prosthesis of 6 +/- 3 mm Hg, mean Doppler-derived valve orifice area of 1.8 +/- 0.6 cm2, and color Doppler flow velocity mapping suggested no regurgitation in eight patients and mild regurgitation in two patients corresponding to early postoperative angiography. None of the 10 patients received anticoagulation therapy. The clinical course of all patients was without incident. This stentless aortic bioprosthesis may offer hemodynamic advantage; however, further studies are needed to allow comparison with conventional mechanical and biologic prostheses.

Adult↗
PubMed1991

[Traumatic aortic rupture: immediate surgery--interval operation?].

On the basis of our own patient population of the last 12 years which involved 17 traumatic ruptures of the descending thoracic aorta in the isthmus area (preoperative hospital mortality at the time of diagnosis: 5.8%; surgical mortality: 27%; postoperative hospital mortality: 18.7%) the problems of assessing indications for surgical intervention in polytraumatized patients with aortic damage are discussed. The indications for "immediate surgery", for "surgery with delayed urgency", and for "surgery in the interval" are clearly defined.

Adolescent↗
PubMed1991

An alternative technique for orthotopic cardiac transplantation, with preservation of the normal anatomy of the right atrium.

The standard technique for orthotopic cardiac transplantation implies large atrial anastomoses which do not preserve the anatomical integrity of the donor atria. This may become a potential source of electrophysiological and mechanical atrial dysfunction, especially in the right atrium with the sinus node and the sensitive low-pressure atrioventricular valve. As an improvement we suggest an alternative technique which we have recently developed for orthotopic cardiac transplantation; it combines the simple, convenient left atrial connection of the standard technique with individual anastomoses of the superior and inferior venae cavae, preserving the right atrium of the donated heart intact. This technique and our first results in two cases are described. Postoperatively, no arrhythmias and no signs of tricuspid insufficiency were observed.

Adult↗
PubMed1991

Unstented and partial stented bioprostheses for aortic valve replacement--up to 6 years of follow-up.

Since January 8, 1985, three different designs of unstented (type A, n = 9) and partial stented (type B, n = 4; and type C, n = 3) glutaraldehyde preserved porcine aortic valves were used for aortic valve replacement in 16 patients with acquired aortic valve lesions. Type A and type B prostheses were implanted using a two suture row technique. In type C prostheses, only a single suture row was necessary for implantation, facilitating surgery considerably. In all patients, the fully flexible commissures of the bioprostheses were secured to the aortic wall of the recipient. There was no hospital mortality. Two patients with type A bioprostheses died due to noncardiac causes, 4 and 24 months postoperatively. One bioprosthesis in this group had to be replaced after 3 months because of insufficiency. Serial Doppler echocardiographic studies were performed up to 6 years after implantation. No significant leaflet calcification was observed. In three type A bioprostheses, a mild insufficiency without progression was recorded. The latest mean/peak transprosthetic pressure gradients were: type A: 6 +/- 4 mmHg/12 +/- 6 mmHg; type B: 6 +/- 3 mmHg/14 +/- 5 mmHg; and type C: 11 +/- 5 mmHg/18 +/- 8 mmHg. The functional results of the type A and type B bioprostheses have proven to be satisfactory. The slightly higher pressure gradients in patients with a type C bioprosthesis give rise to further refinements of its design. These results confirm the usefulness of imitating normal anatomy by using unstented or partial stented bioprostheses.

Adult↗
PubMed1991

[Flexible aortic valve prostheses: long-term functional results with porcine bioprostheses without mechanical commissure stent and aortic homografts].

The long-term performance of two different types of flexible aortic prostheses was evaluated in 10 patients who received a stentless porcine prosthetic valve (group A) and in 18 patients who underwent aortic valve replacement with an aortic homograft (group B). In group A early postoperative angiography (5-16 days post surgery) revealed a mean gradient across the aortic prosthesis of 8 +/- 6 mmHg. Late postoperative Doppler echocardiography (3.2 +/- 0.9 years post surgery) suggested a mean gradient of 6 +/- 3 mmHg with a Doppler derived valve orifice area of 1.8 +/- 0.6 cm2. Color Doppler visualized mild prosthesis regurgitation in two of the 10 patients and two-dimensional imaging showed no significant leaflet calcification. In group B late postoperative Doppler echography (5.2 +/- 1.6 years post surgery) suggested a mean gradient of 11 +/- 14 mmHg with a mean graft orifice area of 1.8 +/- 0.5 cm2. Color Doppler revealed prosthesis regurgitation in 15 patients (severe 1, moderate 2, mild 12) and two-dimensional imaging visualized significant prosthesis leaflet calcification in two patients. The good hemodynamic function of a stentless porcine bioprosthesis which seems to be preserved for at least several years indicates that the use of the flexible aortic xenograft is worthwhile pursuing. The long-term performance of an aortic homograft is relatively poor and may be due to unsolved problems with regard to sterilizing and storing the valves.

Adult↗
PubMed1990

Improved mitral valve replacement.

We describe a simple, reproducible technique of achieving more normal left ventricular function after mitral valve replacement. Polytetrafluoroethylene (PTFE) sutures are used as chordae tendineae to restore the integrity between the mechanical valve and papillary muscles and thus the left ventricular wall.

Chordae Tendineae↗
PubMed1990

Scanning electron microscopy evaluation of the Abiomed 5000 ventricular support system after clinical biventricular assistance.

Twenty-nine days after implantation of an Abiomed 5000 biventricular support system for otherwise intractable end-stage cardiomyopathy, the inner surfaces of the device were examined by means of scanning electron microscopy (SEM). SEM showed clean surfaces inside the blood sacs, with only rare fibrin deposits. There were platelet adhesions on the ventricular side of the artificial atrioventricular valves; no deposits were on the opposite side. Structural deterioration of the closing edge of the artificial valves could be seen. The tubing system was likewise covered by a uniform deposition of single platelets with no major thrombus formation. Postmortem examination of the patient, on the other hand, revealed gross thrombus formation inside both atria at the cannulation sites, despite efficient anticoagulation. We conclude that the Abiomed 5000 per se is unlikely to be the site of major thrombus formation leading to subsequent embolization after 660 h implantation. However, the structural integrity of the adapting areas of the leaflets may become a point of concern. Further research is necessary to improve the atrial cannulation technique in order to prevent the atrial thrombus formation demonstrated as the source of systemic embolization.

Blood Platelets↗
PubMed1990

[Diagnosis of ventricular septum rupture following acute myocardial infarct using a fiber-optic indwelling catheter].

Rupture of the ventricular septum is a rare complication of acute myocardial infarction. Time of diagnosis, hemodynamic condition, as well as duration and effectiveness of the preoperative treatment determine the clinical outcome after surgical repair. Since its introduction the bedside-applied Swan-Ganz catheter has maintained an important role for the rapid confirmation and quantitation of the infarct-induced ventricular septal rupture. We report on the clinical courses of two patients whose diagnoses were established by means of a fiberoptic-armed Swan-Ganz catheter. Accuracy of the measured oxygen saturation was controlled by in vitro gas analyses with heparinized blood samples. As compared to conventional methods the continuous in vivo oximetry by a fiber-optic system is a simple procedure which facilitates repeated shunt calculations during hemodynamic monitoring in critically ill patients.

Catheterization, Swan-Ganz↗
PubMed1989

A "semi-supported" porcine xenograft--description and first clinical use.

The anatomy of valsalva's sinus is such that it decreases the mechanical stress on the leaflets of the aortic valve. Artificial stents impair the hemodynamic performance of an aortic bioprosthesis and lead to unphysiological functional stresses and may also shorten their durability. Therefore a semi-supported xenograft was developed which can be attached with an one-suture row in subcoronary position. This facilitates surgery considerably. Moreover, the commissures can be attached directly to the patient's aortic wall. The semi-supported valve was successfully implanted in a 69 years old patient with a combined aortic valve lesion. Postoperative invasive investigations, including angiography and videodensitometry, showed a normal performance of the valve and a normal anatomy of the aortic root.

Aged↗
PubMed1988

Up to 9 years of follow-up after anatomic correction of simple transposition of the great arteries.

For a continued assessment of the two-stage anatomic correction, we have evaluated the postoperative results in terms of clinical status, ECG, ventricular function, aortic root size and stiffness for up to 9 years in all 18 survivors. Weight and height were normal, the ECG was normal except for complete (n = 3) and incomplete (n = 11) right bundle branch block and supraventricular tachyarrhythmias post Blalock-Hanlon septectomy (n = 1) and p-wave abnormalities (n = 6). The pressures and ejection fraction of the left and right ventricles were within normal limits. The end-diastolic and endsystolic left ventricular volume and the muscle volume index were elevated. Six of 17 patients were outside the normal range of the left ventricular ejection fraction-endsystolic stress relationship. The diameter of the aortic root was larger than normal in all patients. There was a relation between the size of the patients at banding and the stiffness of the aortic root after anatomic correction. Patients with simple transposition of the great arteries up to 9 years after anatomic correction develop normally without atrio-ventricular conduction delay, arrhythmias or signs of coronary and myocardial insufficiency. The stiff and enlarged aortic roots do not seem to dilate. The reasons for the elevated left ventricular volumes and muscle volume indices are not clear at present. Primary anatomic correction may prevent these abnormalities.

Aorta↗
PubMed1986

Cardiac rhythm and conduction after two-stage anatomic correction of simple transposition of the great arteries.

To assess postoperative arrhythmias and AV-conduction defects associated with anatomic correction of simple transposition of the great arteries, 207 standard 12-lead surface and 43 24-hour electrocardiograms of all 17 patients followed after anatomic correction for up to 6.5 years were reviewed. No dysrhythmias or AV-conduction delays definitely attributable to anatomic correction were observed. One patient with a severe complex supraventricular tachyarrhythmia after a Blalock-Hanlon procedure has improved markedly, exhibiting respiratory AV-dissociation and 5 premature atrial complexes/minute 5 years after anatomic correction.

Arrhythmias, Cardiac↗
PubMed1986

Up to 7 years of follow-up after two-stage anatomic correction of simple transposition of the great arteries.

In 16 patients, constituting 100% of children followed for up to 7 years after two-stage anatomic correction of complete transposition of the great arteries, clinical and electrocardiographic data, as well as cardiac catheterization data in 12 patients, were analyzed. None of them has had signs or symptoms of coronary or myocardial insufficiency after an adaptation phase of 6 months after anatomic correction. Body weight normalized 3 to 6 months after anatomic correction, and was normal in most cases after 1 year. No atrioventricular conduction delays or arrhythmias definitely attributable to anatomic correction were observed. Peak systolic pressure in the right ventricle was slightly elevated in 10 of 12 patients studied due to residual pulmonary stenosis from the band site. End-diastolic and end-systolic volumes as well as ejection fraction and end-diastolic pressure of the right ventricle were normal. End-diastolic and end-systolic volumes of the left ventricle were elevated (p less than .01), while muscle volume, ejection fraction, and end-diastolic pressure were normal. The pulmonary root was distended during the banding stage and did not dilate as did the aortic root after anatomic correction. Patients with complete transposition of the great arteries up to 7 years after anatomic correction develop normally without atrioventricular conduction delays, arrhythmias, or signs of coronary and myocardial insufficiency. The enlarged aortic root does not seem to dilate. The reasons for elevated left ventricular volumes are not clear at the present time. Earlier operation may prevent these changes.

Body Weight↗
PubMed1985

Influence of the two-stage anatomic correction of simple transposition of the great arteries on left ventricular function.

To evaluate the influence of the 2-stage anatomic correction of simple transposition of the great arteries on left ventricular (LV) function, pressure and angiocardiographic volume data were analyzed during resting conditions shortly before banding of the pulmonary trunk (n = 12) and before (n = 17) and after anatomic correction (n = 11), and compared with data from controls (n = 12). Age at banding and anatomic correction was between 1 and 44 months (mean 16 +/- 10) and between 13 and 47 months (mean 24 +/- 10), respectively. The interval between anatomic correction and the investigation ranged from 10 to 29 months (mean 20 +/- 7). After banding, LV ejection fraction decreased (p less than 0.01) and LV peak systolic pressure (p less than 0.01) as well as LV end-diastolic pressure (p less than 0.05) increased. After anatomic correction, these variables and LV end-systolic wall stress were not significantly different from control values. The LV end-systolic wall stress-ejection fraction relation in 7 of 11 patients after anatomic correction was within control range. The highest values were found in the youngest patients at banding and at anatomic correction. In contrast to measures of global myocardial function, such as LV ejection fraction and LV end-diastolic pressure data, the LV end-systolic stress-ejection fraction relation suggest that LV function may not be normal in some patients 20 months after anatomic correction. Young age at operation, however, appears to be advantageous in preserving LV function. Hemodynamic alterations after banding probably reflect LV adaptation to systemic pressures in a hypoxemic circulation.

Age Factors↗
PubMed1985

Internal mammary artery as a palliative systemic-pulmonary shunt in order to develop diminutive pulmonary arteries.

Diminutive pulmonary arteries remain a problem in the surgery of congenital heart disease. This is the second report of a case in which the internal mammary artery was successfully used to enlarge small pulmonary arteries by 50% within 9 months accompanied by improvement of the symptomatic state in a patient with pulmonary atresia and diminutive left pulmonary arteries.

Adolescent↗
PubMed1985

Implantation of a xenogeneic stentless aortic bioprosthesis. First experience.

To overcome the specific disadvantages of mechanical valves and stented bioprostheses, we implanted a stentless xenogeneic aortic valve in a patient with calcified aortic stenosis. The postoperative study revealed a pressure gradient of 25 mmHg, a minor insufficiency of 10% of total stroke volume and a slightly restricted motion of the leaflets. Although the implantation of a stentless xenogeneic aortic valve is feasible, one should be aware of the specific technical difficulties due to the increased rigidity of the fixed tissue, which is not known in homografts. To our knowledge this is the first report on the implantation of a stentless xenogeneic aortic valve.

Aortic Valve↗
PubMed1985

Allogeneous transplantation of the mitral valve. An open question.

To overcome the disadvantages of mechanical valves and bioprostheses, especially in the mitral position, transplantation of an allogeneous mitral valve was performed in 3 patients. One transplant had to be removed 8 weeks postoperatively, most probably due to maladjustment of the anterior leaflet during surgery. The histology of this specimen showed not clear signs of rejection. In 2 patients, echocardiography showed a normal motion pattern of the mitral valves 6 months postoperatively. Regurgitation was less than 10% of the total stroke volume as calculated by videodensitometry. Both patients were in excellent clinical condition. Mitral valve transplantation can be performed with excellent short-term results. Further studies including immunologic monitoring are necessary to evaluate the long-term behavior of the transplant.

Adult↗