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Biomedical subjects

A Bernhard

Publications and source records attributed to A Bernhard.

At least 73 records · Page 4Linked to original sources
PubMed1984

Orthotopic transplantation of aortic valve allografts. Early hemodynamic results.

The aortic root as a functional unit includes the sinuses of valsalva, valve ring, the leaflets and the commissures. This unit is impaired by the insertion of a bioprosthetic three-leaflet valve. Moreover, bioprostheses fail because of fatigue and flexion stresses. Consequently a program was started for free-handed orthotopic transplantation of allogeneous aortic valves at the Department of Cardiovascular Surgery, University Kiel. A series of 16 consecutive antibiotic, sterilized aortic valve allografts were transplanted in the last 12 months without death. There were 4 females and 12 males between 18 and 63 years old (mean 47.9). The dominant lesion was aortic regurgitation (in 9), stenosis (in 3) and mixed (in 4). Out of the 13 patients who maintained their allografts, 10 (77%) were in class III and 3 (23%) in class IV of the NYHA functional classification. Four patients improved from class III to class I, and 9 from class III and IV to class II of the NYHA functional classification after surgery. All patients except one had postoperative recatheterization including videodensitometry to quantitate the regurgitation, expressed as a regurgitant fraction ( RGF ) in percent of the total stroke volume of the left ventricle, and pressure measurements to determine systolic gradients across the aortic valve allograft, 3 to 6 days and 9 months after surgery. Eleven (68.75%) patients had no regurgitation, 2 (12.5%) patients had trivial aortic regurgitation with RGF of 7% and 10%, respectively. Three (18.75%) patients had severe aortic valve regurgitation with RGF between 40% and 60% due to technical errors and their allografts had to be replaced.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1984

Late results of valve xenograft conduits between the right ventricle and the pulmonary arteries in patients with pulmonary atresia and extreme tetralogy of Fallot.

Between 1975 and 1982, valve xenograft conduits were used to establish continuity between the right ventricle and the pulmonary arteries in 28 patients between the ages of 3 to 39 years (mean 14.7 years) with 4 hospital deaths (14%). The indications for operation were pulmonary atresia types I and II in 7, extreme tetralogy of Fallot with hypoplastic pulmonary artery and valvular ring in 10, secondary obliteration of the infundibulum following Waterston shunt in 4, pulmonary valve insufficiency after transannular right ventricular outflow tract patch in 5 and tetralogy of Fallot with anomalous coronary artery in 2. Twenty-one patients (87%) between 9 and 41 years of age (mean 17.4 years) were available for follow-up 1/2 to 8 years after operation. The late death incidence during the follow-up period was 8% (2/24). Postoperative cardiac catheterization, which included right and left ventriculogram and measurements of gradients, was performed in 14 patients 4 months to 6 years after operation. Four patients were in New York Heart Association (NYHA) class 1, 6 in class II and 4 in class III. The other 7 non-catheterized patients were in class II. There were resting peak systolic gradients of 15 to 35 mmHg in 4, 36 to 55 mmHg and more than 55 mmHg across the xenograft valve and the proximal anastomosis in 4 other patients. The right and left ventricular end-diastolic pressures (RVEDP, LVEDP) averaged 18 and 17.5 mmHg, respectively, in 3 patients. The mean ratio of PRV/PLV quotient in NYHA class I group was 0.3, in class II 0.45 to 0.7 and in class III greater than 0.7 (including 2 with residual VSD and pulmonary hypertension). Late densitometric studies for assessing pulmonary valve competence revealed regurgitant fraction of up to 40% of the total stroke volume in the absence of a residual shunt 2 to 4 years after conduit implantation. Three children underwent uneventful surgical replacement of calcified xenograft conduit 1 1/2 to 4 1/2 years after surgery with antibiotic-sterilized valve allograft. Four other patients have residual ventricular septal defects (VSD), 2 of them underwent surgical reclosure while the other 2 patients with pulmonary hypertension still have their residual VSD open.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1984

Influence of two-stage anatomic correction on size and distensibility of the anatomic pulmonary/functional aortic root in patients with simple transposition of the great arteries.

To evaluate the results of the two-stage anatomic correction of simple transposition of the great arteries the size, distensibility, and histologic characteristics of the anatomic pulmonary root, which arises from the anatomic left ventricle and which we termed the functional aortic root after anatomic correction, were determined in seven patients before and twice after anatomic correction (mean 43 and 671 days) and the results were compared with those in normal control subjects. The diameter of the systolic sinus of the anatomic pulmonary root increased after banding on the average to 140% of normal, whereas the diameter of the diastolic sinus of the functional aortic root increased after anatomic correction on the average to 150% of normal. Diameters of both the systolic and diastolic sinuses of the functional aortic root remained 30% to 55% larger than normal after anatomic correction. Growth potential of the functional aortic root after anatomic correction was normal, whereas its distensibility, as assessed by determination of the percent change in radius and pressure-strain elastic modulus (stiffness index), was decreased after anatomic correction. This pressure-strain elastic modulus was directly related to the corresponding body surface area and age at banding. In four of five specimens of the anatomic pulmonary arterial wall that were obtained at the time of anatomic correction, fragmentation and shortening of elastic fibers were observed. The histologic characteristics of the pulmonary root in the patient with the smallest body surface area at banding and normal distensibility of the anatomic pulmonary/functional aortic root before and after anatomic correction revealed normal aortic configuration of the elastic tissue.(ABSTRACT TRUNCATED AT 250 WORDS)

Aorta↗
PubMed1983

Catheter evaluation of left ventricular shape and function 1 or more years after anatomic correction of transposition of the great arteries.

Twenty-eight children were reinvestigated by cardiac catheterization and angiography greater than 1 year after anatomic correction of transposition of the great arteries (TGA). Seventeen patients with simple TGA underwent banding of the pulmonary trunk plus or minus systemic to pulmonary artery shunt to prepare the left ventricle for anatomic correction. In addition to TGA, 10 of the remaining 11 patients had a large ventricular septal defect and 1 had an aorticopulmonary window. They required no preparation of the left ventricle. Age at repair ranged from 2 to 120 months (mean 26). Catheterization 12 to 48 months after anatomic repair revealed a left ventricular end-diastolic pressure of 4 to 14 mm Hg (mean 9.5 +/- 2.5 [+/- standard deviation]). Ejection fraction ranged from 52 to 75% (mean 66 +/- 8). Frame-by-frame computer-assisted analysis of left ventricular (LV) contraction and relaxation was performed in 14 patients and compared with normal left ventriculograms. Shape index, derived as 4 pi X cavity area/perimeter2 X 100, was measured in 24 patients and showed a mean index of 89 +/- 3% at end-diastole and 79 +/- 8% at end-systole. A control group had a mean diastolic index of 86 +/- 6% and mean systolic index of 73 +/- 8%. It is concluded that LV shape after anatomic correction tends to be more globular than normal and changes little during systole. LV ejection fraction and end-diastolic pressure are normal.

Adolescent↗
PubMed1983

Short-term hemodynamic results after right ventricular outflow tract reconstruction using a cusp-bearing transannular patch.

Correction of right ventricular outflow tract obstruction remains a challenge to cardiovascular surgeons. In order to relieve this obstruction and at the same time prevent or minimize pulmonary insufficiency, we inserted a cusp-bearing transannular patch (monocusp) in 14 patients. To test this objective, we restudied 13 of these patients 0.5 to 4 months postoperatively, including quantifying pulmonary insufficiency using an accurate videodensitometric method. In all patients a degree of pulmonary insufficiency ranging from 8% to 46% of total stroke volume (mean 22.7 +/- 10.6%) was measured, and in all but one a residual right ventricular outflow pressure gradient of 2 to 22 mm Hg (mean 10 +/- 7 mm Hg) was measured. There was an inverse relation between the degree of pulmonary insufficiency and both the pressure gradient (r = -0.89) and the ratio of the pulmonary valve ring diameter to monocusp depth (r = -0.67). An ideal reconstruction of the right ventricular outflow tract obstruction, without any postoperative pulmonary insufficiency and stenosis, was not achieved by the implantation of a monocusp in the described fashion. The postoperative results were acceptable in only a few patients. A reduction of pulmonary insufficiency seems to be associated with a small residual pressure gradient as well as a relatively small cusp size. Additional studies are necessary to further improve surgical correction of right ventricular outflow tract obstruction with reproducible and predictable results.

Adolescent↗
PubMed1982

Left and right ventricular adaptation to right ventricular overload before and after surgical repair of tetralogy of Fallot.

On the basis of angiographic projections, left (n = 43) and right (n = 56) ventricular volume data were obtained in patients with tetralogy of Fallot before and after surgical repair. The postoperative patients were divided into 3 groups according to the degree of an additional volume load secondary to a residual ventricular septal defect or pulmonary insufficiency, or both. The decreased left ventricular ejection fraction (p less than 0.01) in preoperative tetralogy of Fallot in the presence of a normal sized left ventricle suggests depressed global myocardial function, which is not improved after surgical repair, even if excellent results are achieved. A certain functional reserve, however, seems to be preserved, since the ejection fraction did not decrease further with increasing additional volume loads. Similar enlargement of the right ventricle secondary to comparable degrees of pulmonary insufficiency and residual ventricular septal defect indicates similar effects of additional diastolic and systolic filling on right ventricular function in patients with tetralogy of Fallot after surgical repair. Even in patients with excellent surgical results, such as those without significant right ventricular outflow tract obstruction and additional volume load, right ventricular pump function is depressed, the ejection fraction being significantly (p less than 0.01) lower than normal. The further decrease of global myocardial function with increasing volume load suggests a loss of functional reserve. Attempts to minimize right ventricular volume load after surgical repair seem advisable.

Adolescent↗
PubMed1982

Supravalvular pulmonary stenosis after anatomic correction of transposition of the great arteries: causes and prevention.

Twenty-two patients who underwent anatomic correction of transposition of the great arteries at the arterial level at the age of 8 weeks to 14 years were reinvestigated 1-4.6 years (mean 2.0 years) after operation. A Dacron tube was used to bridge the gap between the proximal pulmonary route and the distal pulmonary artery in four patients and a tube made of homologous dura mater (2.5 cm in diameter) was used in 18. The nonvalved conduit was placed on the right side of the ascending aorta in nine patients and on the left side in 13. Supravalvular pulmonary stenosis with a gradient of 45-95 mm Hg was found in three patients, all of whom had had the conduit placed on the right side. There was normal growth of the pulmonary artery proximal and distal to the stenotic area. Operation for the relief of the stenosis with insertion of a pericardial patch across the stenosed area was performed in two patients. We conclude that supravalvular pulmonary stenosis after anatomic correction of transposition of the great arteries occurs only when the new pulmonary artery is placed on the right side of the ascending aorta and that the use of a large tube of dura mater appears to allow for rapid growth in early life.

Adolescent↗
PubMed1981

Further experience with the two-stage anatomic correction of simple transposition of the great arteries.

Between May 1976 and January 1981 a two-stage anatomic correction was performed in 25 patients with simple transposition of the great arteries, ranging in age from 41/2 to 46 1/2 months (mean 14.8). A first-stage operation, consisting of banding of the pulmonary artery to redevelop the left ventricle, including a Blalock-Taussig-anastomosis in 4 patients was performed prior to anatomic correction. Of 33 patients, who underwent first-stage correction there were 3 early deaths (9%). The interval between the first and second stages was 5 weeks to 9 months (mean 4.3 months). After the first-stage operation, the peak systolic left ventricular pressure rose from 34 +/- 11 mmHg to 80 +/- 16 mmHg with no significant change in enddiastolic pressure. After anatomic correction there were 5 early deaths (20%) of whom 4 were due to left heart failure. There was no correlation between death and the age of the patients at the time of anatomic correction. By our current criteria the ventricles were not adequately prepared for correction in these four patients. The coronary arteries, with different types of origin, could be reimplanted to the posterior vessels without kinking, tension or torsion in all cases. After correction, the ECG and vectorcardiogram rapidly changed toward normal. The arterial oxygen saturation was higher than 95% in all patients. Recatheterization performed in 11 patients, 3 weeks to 27 months after correction, showed normal left ventricular pressure at rest in all children, except in 2 recatheterized early after correction, who had moderately elevated left ventricular enddiastolic pressure. Right ventricular peak systolic pressure decreased to normal limits. The aortic and coronary anastomoses showed normal growth in cineangiography. Although the two-stage corrections of simple TGA may have its own problems, investigation suggests that results are encouraging.

Child, Preschool↗
PubMed1981

Reconstruction of the right ventricular outflow tract in tetralogy of Fallot and pulmonary stenosis with a monocusp patch.

In order to reduce postoperative pulmonary insufficiency (PI) a transannular monocusp patch was implanted in 14 patients with severe tetralogy of Fallot and hypoplastic pulmonary valve ring (group A). The results of left and right heart catheterization, obtained within one year of the correction, were compared to those of 9 patients, who received a simple transannular pericardial patch (group B). The mean maximal systolic pressure ratio between the right and left ventricle (A = 0.43 +/- 0.03; B = 0.49 +/- 0.04), the mean maximal systolic pressure gradient between the right ventricle and the pulmonary artery (A = 10.38 +/- 0.52 mmHg; B = 12.2 +/- 2.5 mmHg), and the degree of PI (A = 24.7 +/- 3.4%; B = 22.0 +/- 3.0% of total stroke volume) were not significantly different (p greater than 0.05) for the 2 groups. Although optimally implanted, the available monocusp patches cannot prevent or reduce postoperative pulmonary insufficiency in patients with severe tetralogy of Fallot. This experience suggests the need for a simple transannular pericardial patch if the pulmonary valve ring requires enlargement.

Adolescent↗
PubMed1981

Two-stage anatomic correction of complete transposition of the great arteries: ventricular volumes and muscle mass.

Between 1976 and 1981, 27 patients with complete transposition of the great arteries, ranging from one month to 2 1/2 years, underwent two-stage anatomic correction and 7 patients first-stage operation only. There were three early deaths after the first-stage and five after the second-stage operation and no late deaths. In seven patients the results of repeat cardiac catheterization including quantitative analysis of ventricular angiocardiograms at the different stages of the procedure were available. In these patients peak systolic pressure in the left ventricle rose to systemic levels after banding of the pulmonary artery. Left ventricular end-diastolic and stroke volumes decreased to normal levels without significant reduction of arterial oxygen saturation. One to 2 1/2 years after anatomic correction left and right ventricular function was normal, as judged by normal end-diastolic pressure, ejection fraction and ratio left ventricular muscle volume/end-diastolic volume. Minimal aortic regurgitation in five patients, mild mitral insufficiency in two and a small VSD in two contributed to elevated end-diastolic volumes of the left ventricle, observed in six patients, and of the right ventricle, found in two patients. The aortic and coronary anastomoses appeared to grow normally.

Angiocardiography↗
PubMed1980

Clinical and hemodynamic results of the two-stage anatomic correction of simple transposition of the great arteries.

Between 1976-1979, 14 patients with simple transposition of the great arteries (TGA), ranging in age from 1 month to 2 1/2 years, underwent two-stage anatomic correction. Twenty patients underwent a first-stage operation, with three early deaths (15%). After the first-stage operation the peak systolic left ventricular pressure rose from 38 +/- 6 mm Hg to 79.6 +/- 11 mm Hg, with no significant change in end-diastolic pressure or ejection fraction. This was associated with a decrease in the actual pulmonary flow but no change in effective pulmonary flow. Between the first and second stages we allowed a 5-week to 9-month interval. There were four early (29%) and no late deaths. Follow-up was 5-37 months. After an initial period of cardiac failure, all patients became asymptomatic and developed normally. Rapid changes in ECG, vectocardiogram and echocardiogram toward normal were observed. Repeat cardiac catheterization was performed in nine patients, 3 weeks to 2 1/2 years after operation. Left ventricular ejection fraction was normal in all. Two who were investigated early had mild mitral regurgitation, five had minimal aortic regurgitation and one had moderate supravalvar pulmonary stenosis. The aortic and coronary anastomoses appeared to grow normally.

Blood Pressure↗
PubMed1979

[Exercise capacity and physical activity following prosthetic valve replacement in relation to cardiovascular function (author's transl)].

31 patients (Pt) with Mitral Valve Repacement (MVR), 22 Pt with Aortic VR (AVR) and 10 Pt with Double VR (DVR) are investigated hemodynamically and by ergometry. Normal working capacity (100% WC) has been achieved in 59% of Pt with AVR, in 34% with MVR and in 22% with DVR. Pulmonary artery mean pressure (PAMP) in this group was 19.5 mmHg, in a second group with a WC of 80% PAMP was 22.2 mmHG. 77% OF Pt with AVR are working regularly, in MVR 58% and in DVR 50%. In the average of these Pt, 7 months after VR professional occupation is started again. PAMP and pulmonary vascular resistance (APR) is significantly lower in the working vs. the non working group: PAMP 19.8/23.7 mmHg; APR 115/145 dynes sec cm-5, respectively. In MVR, the transprosthetic pressure gradient at rest was 4.1 (working PPT) and 7.5 mmHg (other); in AVR statistically no significant difference in the gradient could be found. In general, 68% of the working Pt are employed in a preferably sedentary job. The mean duration of daily work was estimated to 6.7 hours. It is concluded that AVR yields more favourable results in terms of regaining normal working activity than MVR. Cardiovascular function and physical capability in Pt with DVR are approximately comparable to MVR.

Adult↗
PubMed1979

[Reconstruction of the right ventricular outflow tract in tetralogy of Fallot with a Hancock valve containing ventriculo-pulmonary conduit (author's transl)].

Between June 1975 and August 1978, 22 cases of anatomically and functionally severe tetralogy of Fallot were corrected with a valve bearing ventriculo-pulmonary Hancock conduit. The indication for use of the Hancock conduit was atresia of the pulmonary valve ring and main pulmonary artery (classified according to Sommerville and Jefferson as types I and II respectively) in 5 patients, severe hypoplasia of the pulmonary valve ring, the right ventricular outflow tract (RVOT) and the main pulmonary artery in 10, 1 patient with an abnormal right coronary artery and an acquired obstruction of the infundibulum subsequent to Waterston-Cooley anastomosis in 4 patients. Hancock conduits (KHP) were also employed in two patients with severe pulmonary insufficiency after patch insertion across the pulmonary valve ring. Early mortality was 9%. Very good hemodynamic results were achieved in 15 patients (with pRV/pLV ratios less than 0.4 in 8 and between 0.4 and 0.5 in 5 patients). Good results (as indicated by pRV/pLV ratios between 0.5 and 0.7) were found in 7 patients, while only in 2 patients a ratio greater than 0.7 indicated an insufficient hemodynamic result. The valve bearing ventriculo-pulmonary Hancock conduit is the surgical method of choice for various types of atresia of the RVOT. As opposed to transanular reconstruction of the RVOT which, dependent on the extent of hypoplasia, consistently leads to some degree of pulmonary insufficiency, the use of the Hancock conduit can prevent pulmonary regurgitation.

Heart Valve Prosthesis↗