Biomedical subjects

R Hetzer

Publications and source records attributed to R Hetzer.

At least 253 records · Page 14Linked to original sources

PubMed1997

Risk factors for early degeneration of allografts in pulmonary circulation.

OBJECTIVE: The aim of this study was to define risk factors for early degeneration of allografts in pulmonary circulation and to recommend some guidelines to minimize them. METHODS: Between January 1988 and March 1995, 202 patients with various types of congenital heart disease received cryopreserved allograft conduits for reconstruction of their right ventricular outflow tract. We report on 63 patients receiving allografts ranging from 9-24 mm size within the first 2 years of life. RESULTS: Survivors have been followed for 4-67 months. Survival at 5 years, including hospital mortality, was 66%. Two patients died at reoperation. Of the patients 19.6% (9/46) had early structural deterioration (SD) of their vascular allografts at a mean of 15.2 months after implantation. Seven of these have already been reoperated with allograft exchange. Freedom of reoperation was 66% at 5 years. Infants showed 48% freedom of reoperation at 5 years compared to 90% in the 1-2 years age group, while freedom of SD was 59% in infants at 48 months compared to 87% in the 1-2 years age group. Of allografts with SD in the infant group 66% had an allograft size of < 14 mm. In aortic allografts freedom of SD was 62% compared to 93% in pulmonary allografts. Freedom of allograft wall calcification was 46% at 18 months in all patients. In the statistical analysis, only infant age (P = 0.03) and aortic allograft (P = 0.02) were shown to be significant risk factors for early SD. CONCLUSION: The use of pulmonary allografts, avoidance of relatively short and small conduits of < 14 mm in diameter, might improve the durability of allografts in infants and small children.

Bioprosthesis↗

PubMed1997

Myocardial recovery through ECMO after repair of total anomalous pulmonary venous connection: the importance of left heart unloading.

A 7-day-old boy who had been placed on extracorporeal membrane oxygenation on his second day of life developed biventricular failure after undergoing surgical repair of a supracardiac variant of total anomalous pulmonary venous connection. Extracorporeal membrane oxygenation was again necessary for postoperative cardiopulmonary support. However, severe left ventricular failure made it imperative to leave the vertical vein open during support in order to decrease pressure on the left ventricle. The patient was successfully weaned from extracorporeal membrane oxygenation on day 8 after surgery and discharged from the hospital on day 23.

Blood Pressure↗

PubMed1997

Results of left atrioventricular valve reconstruction after previous correction of atrioventricular septal defects.

OBJECTIVE: The objective of this study was to determine causes of severe left atrioventricular (AV) incompetence and the factors leading to the success of valve repair later after correction of atrioventricular septal defects (AVSD). METHODS: A total of 28 patients aged 5 months to 38 years (mean age 6.7 years) were operated for significant (grade II-III) left AV valve incompetence (LAVVI), two months to twenty-five years (median 1.5 years) after correction of complete (11 patients) or partial atrioventricular septal defects. Fourteen patients had initially undergone surgery during infancy. RESULTS: At reoperation a completely open or partially sutured cleft was found in 16 patients combined with dysplastic valve tissue in four cases, with a fibrotic valve in three cases, with posterior leaflet prolapse in two cases, with a double orifice valve in three cases, and a parachute valve in two cases. Partial or complete reopening of a previously sutured cleft caused by suture dehiscence was found in 12 cases combined with a fibrotic valve in five cases, with a dysplastic valve in one case and with severe deformity of valve in one case. A combination of these anomalies was observed in seven patients in both groups. Left atrioventricular valve repair including cleft closure combined with annuloplasty and other surgical procedures resulted in the disappearance or significant diminishing of LAVI in 18 patients (64%). Severe SAVI persisted in six patients, five of them exhibiting a combination of several additional left AV valve anomalies (fibrotic or dysplastic valve, parachute valve). Five of these six patients underwent successful left AV valve replacement with a mechanical prosthesis 7 days to 2 years after reoperation. The presence of additional left AV valve anomalies was the single statistically significant factor for recurrent major LAVVI after reoperation (P = 0.0106). There were two postoperative deaths in patients with mild LAVVI after surgery, and no late deaths. CONCLUSION: An open cleft is the major factor of late severe SAVVI after correction of AVSD. Although suturing the cleft in conjunction with performing annuloplasty improved valvular function in most of the cases, the presence of severe left AV valve anomalies increased the risk of recurrent LAVVI and the need for valve replacement, thus playing a major role in determining the outcome of valve reconstruction in patients after reoperation.

Adolescent↗

PubMed1997

Circulatory support with paracorporeal pneumatic ventricular assist device (VAD) in infants and children.

OBJECTIVE: The feasibility and efficacy of the pneumatic 'Berlin Heart' ventricular assist device (VAD) were evaluated in 14 pediatric patients with profound cardiogenic shock refractory to conventional therapy. METHODS: There were two patient groups. Eleven patients, aged 2 weeks 15 years and weighing 3.2-52 kg received a left ventricular assist device or a biventricular assist device as a bridge to cardiac transplantation (bridge group). Nine of them had liver, kidney, or lung dysfunction before device implantation. Three patients were supported with a biventricular assist device for myocardial recovery (recovery group): a 6-month-old girl for postcardiotomy shock, a 10-month-old girl for allograft failure after cardiac transplantation, and a 4-year-old boy with acute myocarditis. RESULTS: In the bridge group, eight patients were transplanted after a bridge duration of 6-98 days (mean, 32 days) with five long-term survivors. Organ functions were normalized during bridging in all of the transplant recipients. In the recovery group, the first patient was removed from support after 2 days because of irreversible brain damage. The second patient was weaned from biventricular support after 8 days, but suffered from recurrent allograft failure. The third patient received biventricular support for 21 days followed by extracorporeal membrane oxygenation and was subsequently discharged from the hospital. CONCLUSIONS: The 'Berlin Heart' VAD can keep selected infants and children with life-threatening heart failure for weeks or months.

Adolescent↗

PubMed1997

Imaging of the orifice of the left ventricular outflow tract: technique and initial results.

The mechanism of left ventricular outflow tract (LVOT) obstruction in the patient after mitral valve replacement or repair was examined with the aid of 2D echocardiography. For the interpretation of the spatial relationship between the aortic root and mitral annulus, however, the 2D display is sometimes inadequate since it may not simultaneously capture these structures in each center. We developed a method to clarify this relationship in 3D based on magnetic resonance images. We defined the office of the left ventricular outflow tract (LVOT orifice), consisting of, in turn, a muscular region, i.e., edge of the interventricular septum, and an annular region, i.e., the annulus of the anterior mitral leaflet. In this paper we present image data obtained from one of eight normal subjects examined and compare this with data of one of two patients who preoperatively suffered degenerative mitral regurgitation and subsequently underwent chordal-preserving mitral valve replacement, in which anterior chordae were reattached to the anterior annulus. In the normal subject, the mitral annulus exhibited a flexible change in shape during the systole, maintaining sufficient LVOT orifice size. In the patient, the prosthetic valve exhibited translational motion during systole, resulting in dynamic LVOT obstruction. This phenomenon was also observed in one other case. Furthermore, the lateral view of the LVOT orifice revealed a projection of the prosthetic valve into the LVOT, causing mechanical LVOT obstruction. The finding that translational motion of the prosthetic valve with an inflexible mitral annulus results in dynamic LVOT obstruction may support the hypothesis that annular rigidity causes dynamic LVOT obstruction after mitral valve repair with a rigid prosthetic ring.

Adult↗

PubMed1997

Long-term mechanical circulatory support as a bridge to transplantation, for recovery from cardiomyopathy, and for permanent replacement.

Since 1988, 295 patients have undergone MCS at the German Heart Institute Berlin; 246 received biventricular support with the extracorporeal pneumatically-driven Berlin Heart Assist Device, 49 received left ventricular support with implantable assist devices (33 Novacor, 16 TCI). Longer waiting periods for heart transplantation has caused the mean duration of MCS to increase from 12 days in 1988 to 76 days in 1994. Of the 24 patients who underwent MCS for more than 90 days, nine were implanted with a biventricular device, 12 with a Novacor device, and 15 with a TCI device. Eight patients with uni-ventricular devices remain on support after 200 days (range 203-600 days). Six of the Novacor patients could be discharged to a nursing home or to their own residences. One patient still on NC support after more than 600 days currently resides at his home and has regained normal physical activity. Minor pocket infections occurred in two TCI and four Novacor patients; one patient died of sepsis. A total of four patients could be weaned from LVAD after 160-347 days of MCS. An initial high level of beta1 receptor antibodies disappeared completely during left ventricular support. This decline in auto-antibodies was paralleled by a dramatic improvement in cardiac function. LVEF remained unchanged up to 6 months after explantation. Long-term mechanical support has become a reality. Heart transplantation after prolonged MCS yields results comparable to primary HTx. Some patients exhibit immunological changes and a dramatic improvement in ventricular function under long-term MCS and can be weaned with extremely satisfying results.

Adolescent↗

PubMed1997

Successful mechanical circulatory support for more than two years with a left ventricular assist device in a patient with dilated cardiomyopathy.

A 36-year-old man with dilated cardiomyopathy was supported with a left ventricular assist device for 795 days. During this support time gradual functional recovery was noted. The patient tolerated the device well, enjoyed a good quality of life, and experienced no technical device-related problems. When a suitable donor heart became available, the device was switched off, and native ventricular function was assessed. This was judged to be acceptable, and the left ventricular assist device was successfully explanted. Postexplantation function remained acceptable and improved over the following days. The patient was discharged on the twentieth postoperative day and remains well.

Adult↗

PubMed1997

[Surgical therapy of chronic atrial fibrillation with the "Cox/Maze-III-operation"].

UNLABELLED: We examined the results of simultaneous surgical treatment of chronic atrial fibrillation using a Cox/Maze III operation during mitral valve surgery (n = 12), atrial secundum defect closure (n = 1), combined operation (mitral valve and atrial secundum; n = 1) and thrombectomy from the left atrium (n = 1). Mean preoperative atrial fibrillation was 5.1 years (range 0.5-12 years). In the mean follow-up period of 13.1 months (1-24 months), 14 patients (93%) had sinus rhythm. CONCLUSION: (1) The surgical treatment of chronic atrial fibrillation using a Cox/Maze III operation can be performed without increased perioperative or postoperative risks; (2) Cox/Maze III operation represents an effective surgical treatment of chronic atrial fibrillation.

Aged↗

PubMed1996

Reduced atrial angiotensin receptor type 1 mRNA content in end-stage human heart failure: assessment by a novel quantitative PCR-ELISA technique.

The number of atrial angiotensin II binding sites is reduced in end-stage human heart failure. The goals of our study were the development of a quantitative polymerase chain reaction for angiotensin II receptor type 1 mRNA to determine the angiotensin receptor type 1 (AT1) mRNA content in the atria of patients with end-stage heart failure. We established a quantitative PCR based on coamplification of AT1 wild-type and an internal standard in the same PCR, followed by liquid-phase hybridization of PCR products in microtiter plates and quantitation by ELISA. Glyceraldehyde phosphate dehydrogenase mRNA in the same samples was used to relate the AT1 mRNA content to a stably expressed reference gene. Atrial samples from 11 patients with end-stage heart failure obtained at cardiac transplantation were compared with atrial samples from 11 patients with normal cardiac function undergoing routine cardiac surgery. A PCR/ELISA system with a variance of about 6% after reverse transcription and a linear measuring range was established. In the samples from 11 patients with end-stage heart failure a 58% decrease in AT1 mRNA content was found in comparison with 11 controls (heart failure: 185,680 +/- 196,912 AT1 mRNA copies/microgram RNA, controls: 440,555 +/- 268,456, P < 0.02). When AT1 mRNA content was related to glyceraldehyde phosphate dehydrogenase mRNA, a 65% decrease was detected (AT1/glyceraldehyde phosphate dehydrogenase: heart failure: 4.84 +/- 5.18; controls: 13.74 +/- 7.77; P < 0.005). Standardization of PCR resulting in a low coefficient of variance, high reproducibility, and large sample capacity is possible using optimal internal standardization and the liquid-phase hybridization/ELISA system for detection. The optimized PCR procedure indicated downregulation of atrial AT1 in end-stage human heart failure, suggesting a reduced capacity of the atria to respond to angiotensin II stimulation in end-stage heart failure.

Angiotensin-Converting Enzyme Inhibitors↗

PubMed1996

Decreased expression of ventricular angiotensin receptor type 1 mRNA after human heart transplantation.

Myocardial angiotensin receptors of type 1 (AT1) are downregulated at the protein and mRNA levels in human heart failure. No data are available for the transplanted human heart, which frequently exhibits functional alterations. The aim of the present study was the quantitation of ventricular AT1 mRNA content in endomyocardial biopsies from patients after heart transplantation. For the determination of AT1 mRNA we used a novel quantitative reverse transcription polymerase chain reaction with low variance (6%) based on an internal AT1 cRNA standard, liquid-phase hybridization of polymerase chain reaction products in microtiter plates, and quantitation by enzyme-linked immunosorbent assay. Right ventricular biopsies from 16 patients after heart transplantation (left ventricular ejection fraction 67 +/- 7%) were compared with 12 patients with normal cardiac function (left ventricular ejection fraction 62 +/- 5%). A 46% lower AT1 mRNA content was found in biopsies from the 16 patients after heart transplantation than in the 12 controls (heart transplantation, 200 +/- 25 AT1 mRNA copies/ng RNA; controls, 368 +/- 50; P < 0.01). When AT1 mRNA content was related to the stably expressed GAPDH mRNA, a 49% decrease was detected (AT1/GAPDH: patients, 2.4 +/- 0.25; controls, 4.7 +/- 0.6; P < 0.006). No association between the extent of AT1 downregulation and clinical or hemodynamic variables was detected. In the human heart ventricular AT1 is downregulated after orthotopic heart transplantation. The decrease in AT1 mRNA is not associated with altered systolic function. This may partially reflect a loss of autonomic nerves and thus altered nervous control of the heart.

Adolescent↗

PubMed1996

Impact of mechanical heart valve prosthesis sound on patients' quality of life.

BACKGROUND: The "click" sound of mechanical heart valve prostheses has been recognized as a disturbing factor for some patients after mechanical heart valve implantation. The factors determining the extent of disturbance remain controversial. METHODS: Ninety-five unmatched patients with six different valve types were examined (Duromedics-Edwards, Björk-Shiley, St. Jude Medical, Medtronic, CarboMedics, and Omnicarbon), including 12 patients with double-valve replacement. Three groups (Björk-Shiley, Duromedics-Edwards, and St. Jude Medical) were comparable in size. All patients were examined and interviewed, a hearing test was performed, and valve sounds were analyzed. Sound transmission was evaluated. RESULTS: The loudest valve was the Duromedics-Edwards prosthesis (mean, 84.2 dB[A] impulse) and the St. Jude Medical was the quietest (mean, 73.5 dB[A] impulse). This ranking was independent of patient variables and valve position. Discomfort level correlated with hearing loss and loudness of the valve. Patients desiring a quieter valve had better hearing, had louder valve sounds, felt disturbed by the sound, had partners who felt disturbed, and were receiving coumarin for anticoagulation. Sound was transmitted predominantly by air conduction. The frequency analysis to identify different valves was unsatisfactory, but louder frequencies did correspond with hearing-impaired patients' audiograms. CONCLUSIONS: Our results emphasize the need for valve design changes, preoperative education about the sound, and inclusion of routine hearing tests into the preoperative workup.

Adult↗

PubMed1996

Using aortic allograft material to treat mycotic aneurysms of the thoracic aorta.

BACKGROUND: Although mycotic aneurysms are rare in this age of antibiotics, they nevertheless represent life-threatening lesions of the aortic wall because of their high incidence of rupture and significantly high rate of recurrence. METHODS: Between March 1988 and August 1994, cryopreserved allograft material was used to treat 8 patients (mean age, 62.5 years; range, 47 to 80 years) with mycotic aneurysms of the thoracic aorta at our institution. Two patients had emergency operations; the other operations in 6 patients were elective. The aneurysms were located at the previous cannulation site of the aorta (n = 1) or at the donor/recipient aortic anastomosis (n = 1) in the patients who had heart transplantation, in the ascending aorta in 3 patients with aortic valve endocarditis, in the aortic arch in 2, and in the descending aorta in 1. The operative technique consisted of excision of the mycotic aneurysm followed by allograft patch reconstruction in 5 patients, an allograft composite graft replacement of the ascending aorta in 2 patients with endocarditis, and combined aortic allograft root replacement and allograft patch reconstruction of the ascending aorta in 1 patient. RESULTS: The underlying infections of the aorta were treated successfully in 6 patients. One heart transplant recipient had reoperation because of recurrent mycotic aneurysm after allograft patch reconstruction at the donor/recipient anastomosis. There was one early death involving a patient with Salmonella sp sepsis. CONCLUSIONS: The use of aortic allograft material for repairing mycotic aortic aneurysms is a promising and effective operative concept for managing thoracic aortic infections.

Aged↗

PubMed1996

Development of subneopulmonary obstruction early after arterial switch operation in an adult.

In a 19-year-old woman who had previously undergone pulmonary artery banding at the age of 1.5 years, a muscular right ventricular outflow tract obstruction developed 3 days after an arterial switch operation. Although conservative therapy proved successful, prophylactic surgical intervention on the conal septum may be beneficial in preventing the postoperative development of right ventricular outflow tract obstruction.

Adult↗

PubMed1996

Repair of coarctation of the aorta in adults: the fate of systolic hypertension.

BACKGROUND: The benefit of coarctation repair in adults has been questioned by suggesting that hypertension may not be relieved by the operation and that surgical intervention may have no impact on the natural history of the disease. METHODS: To delineate the impact of surgical intervention on systolic hypertension, we conducted a retrospective review of 26 adults with a mean age of 32 +/- 10 years who underwent coarctation repair between 1987 and 1993. All patients were hypertensive (mean systolic blood pressure, 174 +/- 21 mm Hg; range, 140 to 220 mm Hg), and 18 patients (69%) were on a regimen of at least one hypertensive medication at the time of surgical admission. All patients underwent catheterization, and the mean peak systolic gradient across the coarctation was 61 +/- 25 mm Hg (range, 25 to 120 mm Hg). Operation included resection and end-to-end anastomosis (3 patients), resection with an interposition tube graft (6 patients), a bypass graft (11 patients), and patch angioplasty (6 patients). There was no hospital mortality or late morbidity. RESULTS: Intermediate follow-up was available at a mean of 2.3 +/- 2 years (range, 1 to 7 years). At last follow-up, the peak systolic gradient between the upper and lower body was trivial (< or = 10 mm Hg) in 23 patients (88%) and mild (11 to 20 mm Hg) in 3 (12%). All patients had significant improvement in systolic blood pressure (p < 0.001) compared to preoperative values, and the majority (23, 88%) were normotensive. More than half of the patients (14, 54%) were still on a regimen of antihypertensive medication at last follow-up, with a trend (p = 0.06) toward older patients requiring medication. CONCLUSIONS: Surgical repair of coarctation in adults is an effective, low-risk procedure, which results in a significant improvement in systolic hypertension and a decreased requirement of antihypertensive medications.

Adult↗

PubMed1996

Long-term extracorporeal membrane oxygenation in a newborn child after arterial switch operation.

A 7-day newborn girl with d-transposition of the great arteries (d-TGA) and complex coronary anatomy developed global myocardial dysfunction after arterial switch operation despite establishment of an effective coronary circulation. Extracorporeal membrane oxygenation was used for circulatory support for 163 h after the operation. On day 7 after surgery she was successfully weaned from extracorporeal membrane oxygenation and is currently symptom-free 10 months after the operation. This case illustrates the effectiveness of extracorporeal membrane oxygenation for circulatory support after the arterial switch operation. In such cases, establishing adequate coronary circulation during surgery mandatory to ensure a successful postoperative myocardial recovery.

Cardiomyopathies↗

PubMed1996

Heart transplantation: a single-center experience.

BACKGROUND: The success of heart transplantation led to the extension of the criteria for both recipients and donors. The aim of the study was to evaluate the experience with this therapeutic approach for end-stage heart failure at a single center. METHODS: Between April 1986 and January 1996, 1,413 patients were accepted as candidates for heart transplantation. Ventricular assist devices were used as a bridge to transplantation in 173 patients (biventricular assist device in 141 patients and left ventricular assist device in 32 patients). The longest duration of support was 572 days (average, 46 days). RESULTS: Of the 1,413 patients, 891 underwent heart transplantation (65 children/adolescents and 826 adults; 522 (36%) patients died awaiting a donor heart. The average time spent on the waiting list was 107 days. The average recipient age was 44 years, and the age of donors was extended up to 69 years. Eighty-three patients with ventricular assist devices (48%) subsequently underwent heart transplantation. Twenty-five patients (2.7%) underwent retransplantation. The 30-day mortality rate was 14%, and the overall actual survival at 1, 5, and 10 years was 80%, 59%, and 50%, respectively. Ninety-four percent of patients were in New York Heart Association functional class I or II at 1 year, and 44% returned to work after transplantation. CONCLUSIONS: Despite the broadening of the selection criteria for both recipients and donors, heart transplantation remains an effective treatment for end-stage heart failure. Nevertheless, this therapeutic approach is severely limited by a considerable disparity between the need and availability of donor organs.

Adolescent↗

PubMed1996

Morphometric techniques in the evaluation of pulmonary vascular changes due to congenital heart disease.

Open lung biopsy is performed in patients with congenital heart disease to determine the suitability for surgical correction. Controversy exists as to whether arterial density can be graded with certainty. We studied the influence on the grading (Heath-Edwards) of two morphometric techniques. Lung tissue from 14 controls and biopsy specimens from 80 patients with atrial septal defect (n=10) ventricular septal defect (n=27), complete atrioventricular canal (n=27), miscellaneous lesions (n=8) and tetralogy of Fallot (n=8) were analyzed with a planimetric method. Additionally, wall thickness was determined in 52 patients by distance measurements. The ratio of alveoli/arteries per area of lung tissue was measured. Medial thickness was "increased" on distance measurements in 15% of the cases where planimetric data showed normal wall thickness. The ratio of alveoli/arteries varied up to 43% from the mean. Hemodynamic data obtained at a median (range) time of 2 months (1 day to 18 months) before the operation did not correlate with morphologic findings. In 27 patients hemodynamic data were recorded at a median time of 1 year (3 days to 44 months) after the operation. Intimal fibrosis occupying more than 10% of the vessel lumen was associated with persistent high pulmonary vascular resistance. We conclude that morphometric techniques are useful to determine the degree of fibrosis in advanced vascular lesions. Arterial density cannot be determined in biopsy specimens with adequate certainty.

Adolescent↗

PubMed1996

Clinical value of echocardiographic tissue characterization in the diagnosis of myocarditis.

Inflammatory changes in the myocardium have been visually observed as alterations on echocardiograms. The goal of this study was to determine how these myocardial changes affect the texture of echocardiographic images, and how these could be described through quantitative texture analysis. The results of 142 endomyocardial biopsies were compared with those of texture analysis in echocardiograms of 106 patients suspected of having myocarditis. There were 52 cases of biopsy-proven acute myocarditis, 12 of persistent myocarditis, nine of healed myocarditis without fibrosis, 17 of healed myocarditis with fibrosis, and 35 cases of cardiomyopathy. Eight myocardial biopsies exhibited no pathological changes and nine patients had other cardiac problems. The echocardiograms of a control group of 24 healthy subjects were also evaluated by texture analysis. Three texture parameters were able to differentiate between normal and abnormal myocardium. The mean grey value, i.e. average brightness, was appreciably higher in cases of myocarditis than in control subjects, whereas one co-occurrence and one run length feature had markedly decreased. We conclude that myocarditis and fibrosis induce changes in echocardiographic image texture, i.e. increases in brightness, heterogeneity, and contrast. Performing digital image texture analysis of echocardiograms makes it possible to distinguish between myocarditis and normal myocardium.

Adult↗