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Biomedical subjects

R Hetzer

Publications and source records attributed to R Hetzer.

464 records · Page 26Linked to original sources
PubMedDate not supplied

Clinical heart transplantation without routine endomyocardial biopsy.

In a prospective clinical study, routine endomyocardial biopsy (EMB) for early detection of cardiac allograft rejection was replaced by two noninvasive diagnostic techniques. In 32 patients who underwent transplantation during a 6-month period, intramyocardial electrogram (IMEG) amplitude was recorded with the telemetry function of a dual-chamber pacemaker system. An amplitude decrease of more than 8% below the individual range of variability in overnight long-term recordings served as an indicator of rejection. A prolongation of the time interval Te--the time span between maximal posterior wall contraction and peak retraction velocity--of more than 20 msec was used as an additional indicator of rejection-related left ventricular dysfunction. For patient safety, routine EMBs were still performed but remained undisclosed to the transplantation team. The pathologist was asked to intervene in cases of discrepancies between biopsy results and medical decisions, but no such intervention was necessary. Twenty-seven rejection episodes were treated medically, of which 22 were diagnosed noninvasively. In four patients, EMB, ordered because noninvasive parameters remained inconclusive, led to medical treatment. No false negative IMEG results were observed. Retrospective correlation with rejection gave a 100% negative predictive value for IMEG and a 96.9% negative predictive value for echocardiographic diagnosis. We conclude that omission of a schedule of routine biopsies is justified, if the described techniques of IMEG and echocardiography are meticulously applied and indicate normal cardiac function. EMB remains indicated if noninvasive parameters are not conclusive or if false-positive IMEG results, which were observed in the presence of infection or arrhythmias, are suspected. The frequency of EMB can be reduced by 90%, compared to conventional routine biopsy schedules. Diagnostic safety is increased because the additional information gained from IMEG and echocardiography is helpful in the interpretation of EMBs.

Biopsy↗
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Mechanical circulatory support and heart transplantation.

Mechanical circulatory support systems are currently in clinical use to keep patients alive with the aim of either cardiac recovery after open heart surgery, myocardial infarction and after heart transplantation with acute graft failure, or as a bridge to transplantation in heart transplant candidates. At the German Heart Institute the "Berlin Heart" mechanical circulatory support system has been used invariably since 1987. Up to 1991 there were 22 patients in the "recovery" group. Four patients could be weaned from the system, but only one patient was discharged from the hospital. In 65 patients mechanical circulatory support systems were implanted as a bridge to transplantation, 39 patients had transplants, and 22 patients left the hospital. Risk factor analysis in the bridging group revealed that previous heart surgery, infective pneumonia, shock-related coagulation disorders, and an age greater than 50 years had an unfavorable influence on patient survival. It is concluded that patients may be kept alive for weeks and months after any kind of cardiogenic shock. Complete cardiac recovery may be achieved in the case of early posttransplant graft failure. Reliable prediction of outcome in the bridge to transplantation group requires further experience.

Female↗
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Role of cytomegalovirus infection in the development of coronary artery disease in the transplanted heart.

In heart transplantation, accelerated graft arteriosclerosis leading to late postoperative graft failure is still an unsolved problem, and its pathogenesis is poorly understood. The existence of multiple underlying mechanisms has been discussed without conclusive results. In kidney transplantation, a negative influence of cytomegalovirus infection on long-term graft function and patient survival could be demonstrated. To evaluate the role of this infection on the incidence of coronary artery disease in the transplanted heart, we have analyzed the cytomegalovirus serostatus in 38 long-term survivors of orthotopic heart transplantation. In 14 patients (group A) graft arteriosclerosis was diagnosed by means of coronary angiography. In 24 patients (group B) the coronary vessels showed no pathologic findings. In 10 patients (71%) of group A serologic study showed evidence of cytomegalovirus infection, whereas only five patients (24%) of group B revealed cytomegalovirus infection. In two further patients of this group herpes zoster infection occurred (p less than 0.0001). Cytomegalovirus infection seems to be an important factor in the development of accelerated graft arteriosclerosis in the transplanted heart.

Adult↗
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Clinical use of the Berlin Biventricular Assist Device as a bridge to transplantation.

The Berlin Artificial Heart System/Biventricular Assist Device (BVAD) was used in 38 patients. 1) Twenty-eight patients were awaiting cardiac transplantation (Tx) (age 23-56 yrs). All patients had contraindications not allowing immediate Tx. 2) Five patients were emergency cases not on our Tx list (postcardiotomy cardiac failure, acute myocarditis) (age 28-59). 3) Five patients were post Tx patients with graft failure (age 22-52). Extracorporal circulation was used for implantation of the BVAD. In group 1, 21 of 28 patients (pts) recovered, and all were subsequently transplanted after 6 hours to 39 days, when all organ function was restored. In 7 pts, mechanical circulation was terminated after 1-40 days because of further deterioration. Five of the transplanted pts died, 14 pts survived (greater than 30 days), and 2 pts were just transplanted with satisfactory postoperative courses. Of group 2 and 3 pts, two were successfully weaned. In one patient the allograft recovered after 11 days of support.

Cardiac Output↗
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Some histopathologic aspects regarding onset of antirejection therapy after heart transplantation.

The histopathologic indication for starting antirejection therapy has so far been given by the diagnosis of moderate rejection in endomyocardial biopsies, that is, rejection with necroses of myocytes and predominantly lymphocytic infiltrates (corresponding to the descriptive diagnosis of moderate rejection in the Stanford classification, grade 4 and more in the Texas classification, and A-3 moderate rejection in the Hannover classification). Our present results, however, have shown that the critical limit for the onset of antirejection therapy may be fixed somewhat higher on the scale of severity of acute rejection and that it may be reasonable to define an affection of more than 20% of the total biopsy material by morphologic changes corresponding to the traditional definition of moderate acute rejection as the decisive histopathologic finding that should induce antirejection therapy. This means that the diagnosis of moderate rejection has to be divided into two groups: (1) A-3a moderate acute rejection not yet requiring therapy that, however, does necessitate bioptic control within 7 to 10 days; (2) A-3b moderate acute rejection requiring antirejection therapy. The introduction of this differentiation of histopathologic diagnoses is not just another sophisticated scientific theorem; its practical significance may be seen in a definitive restriction of the application of antirejection therapy, which means a reduction of the risks and side effects imposed on heart-transplanted patients by chemotherapy and particularly by steroid therapy.

Biopsy↗
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Extended donor criteria for heart transplantation.

The shortage of ideal donor hearts had led to an increasing number of would-be heart transplant recipients who die while on the waiting list. Therefore analogous to kidney and liver transplantation, an extension of the classical donor criteria became necessary, especially for high-urgency recipients. In a series of 121 orthotopic heart transplantations in 117 patients with a 1-year survival of 77%, the criteria for the selection of donor hearts have been gradually extended. Hearts from donors over 40 years of age but not exceeding 50 years were accepted without coronary angiography for 25 patients. There was no immediate graft failure, and the mean postoperative left ventricular ejection fraction, as assessed by radionuclide ventriculography, was normal. The incidence of late postoperative graft atherosclerosis was slightly but not significantly higher. Donor hearts with severe chest trauma, including bilateral hemothorax, rib fractures, and aortic hematoma were accepted for 11 patients. Immediate graft function was normal in all organs. In seven donors the body weight difference was more than 20%. Three patients with smaller grafts with more than 30% body weight difference had a highly complicated postoperative condition. In one patient acute graft failure was reversible with the administration of high dosages of catecholamines. In the other two patients, however, retransplantation was required because of irreversible failure. Episodes of hypotension that did not exceed 30 minutes had no substantial influence on postoperative graft function. The 1-year survival of recipients with donor grafts not complying with standard criteria was not significantly worse than the survival of patients whose grafts were selected according to the standard (76% versus 79%).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
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Heart transplantation in patients with muscular dystrophy associated with end-stage cardiomyopathy.

Until now, patients with muscular dystrophy and concomitant cardiomyopathy have been accepted for heart transplantation only reluctantly, because of a higher perioperative risk caused by physical disability and a suspected rapid onset of cardiomyopathy of the transplanted heart. Of a total of 582 heart transplant recipients, six patients had muscular dystrophy associated with end-stage cardiomyopathy. In three patients, preoperative neurologic diagnostic investigation revealed type Duchenne muscular dystrophy (three male); one female patient had Emery-Dreifuss; one male patient had Becker-Kiener dystrophy, and the specific classification could not be established in one male patient. Mean age was 25 years, ranging from 9 to 45 years. The postoperative follow-up ranges from 10 months to 7 years, with a mean of 40 months. All patients received triple-drug immunosuppression, consisting of azathioprine, cyclosporine, and steroids. All patients had an uneventful postoperative course. Postoperative time of intubation was not prolonged in these patients compared to other patients. All patients are physically rehabilitated. One patient died suddenly 27 months after operation. Annual recatheterization studies showed normal left ventricular ejection fraction (59.5 +/- 13.4% SD). Signs of coronary artery disease could not be observed. No progression of preexisting muscular dystrophy could be diagnosed, until now.

Adult↗
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Aspergillosis with Aspergillus osteomyelitis and diskitis after heart transplantation: surgical and medical management.

This is the report of a 49-year-old man, who could be cured of aspergillosis with Aspergillus osteomyelitis and diskitis of the lumbar spine by medical and surgical therapy after heart retransplantation. Aspergillus osteomyelitis and diskitis is a rare complication of invasive aspergillosis. Lumbar involvement is the main manifestation, followed by rare locations in the tibia, ribs, wrist, sternum, pelvis, and knee. It is nearly always secondary to pulmonary aspergillosis, which occurs in about 6% to 14% of patients after heart transplantation. For treatment, a combined surgical and medical approach is recommended, which enables quick pain relief for the patient and histologic and microbiologic diagnosis and stabilization of the spine. Because of definitive cure of osteomyelitis cannot be guaranteed by removal of the abscess, medical therapy after surgery is necessary for years.

Amphotericin B↗
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Coronary artery disease in patients with hearts from older donors: morphologic features and therapeutic implications.

Of 558 heart transplant recipients, 234 long-term survivors (more than 12 months) were studied by annual catheterization to evaluate the risk of postoperative coronary artery disease in hearts from older donors. No significant difference was found in graft function between hearts from younger and older donors (group I: n = 157, mean donor age 23 +/- 5 years, mean follow-up 45 +/- 22 months; group II: n = 77, mean donor age 43 +/- 5 years, mean follow-up 42 +/- 22 months) as indicated by left and right ventricular ejection fraction, pulmonary artery pressure, and pulmonary capillary wedge pressure. Two morphologic patterns of coronary artery disease were observed: a diffuse type of concentric narrowing of the arteries (type 1) and a focal type with proximal single-vessel stenosis (type 2). Type 1 occurred in eight patients (5%) in group I and in four patients in group II (5%) (p = not significant). Type 1 coronary artery disease led to graft failure in seven patients in group I and two patients in group II. Type 2 coronary artery disease occurred in seven patients (4%) in group I and in 14 (18%) in group II (p < 0.001). No death was related to graft failure in patients with type 2 coronary artery disease. Eight patients with type 2 coronary artery disease were successfully treated by percutaneous transluminal coronary angioplasty; one patient underwent coronary artery bypass grafting. Hearts from older donors provide normal graft function. The risk of diffuse coronary artery disease is not elevated in comparison to hearts from younger donors. The higher incidence of focal coronary artery disease suggests donor-transmitted disease that can successfully be treated by conventional therapy.

Actuarial Analysis↗
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Reliable noninvasive rejection diagnosis after heart transplantation in childhood.

Rejection diagnosis was exclusively handled with noninvasive techniques in 16 children (mean age, 8.6 +/- 5.7 years; range, 0.9 to 15.2 years) over a total follow-up period of 18.3 patient years. No endomyocardial biopsies were performed. Intramyocardial electrogram recordings and echocardiographic investigations were used as two noninvasive techniques for rejection diagnosis. Daily noninvasive telemetric monitoring of the overnight intramyocardial electrogram was the major diagnostic guideline. The intramyocardial electrogram signal of the sleeping child was transmitted to a bedside receiver by an implanted telemetric pacemaker. The QRS amplitude was automatically analyzed and transferred to the in-hospital computer via a telephone modem connection. Rejection was diagnosed when QRS amplitude fell more than 8% below average baseline levels for 3 successive days, which was the indication for hospital admission. Medical antirejection treatment was instituted only if echocardiography showed impaired early diastolic left ventricular relaxation concomitant with a QRS-amplitude loss. The echocardiographic criterion was a prolongation of the parameter Te (Te is defined as the time span between onset of diastole and peak relaxation velocity of left ventricular wall) by more than 10 milliseconds compared to previous intraindividual values. Survival after a mean follow-up time of 13.7 months (range, 2 to 57 months) is 100%. A total of 22 rejection episodes were treated. During the first 6 postoperative months, the incidence of rejection requiring treatment was 1.4 episodes per patient. In patients at home, distant monitoring detected 13 episodes of a significant QRS-amplitude drop, which led to hospital readmission. In eight children, echocardiography was likewise positive, and rejection treatment was instituted. One child with positive intramyocardial electrography received antirejection treatment because of clinical evidence of rejection, although echocardiography was negative. In three instances, systemic infection was associated with the QRS-voltage loss. In one child a reason for QRS-complex reduction could not be identified. One rejection episode was treated on the grounds of clinical signs and positive echocardiography without a significant QRS-voltage drop. We conclude that distant noninvasive rejection monitoring based on meticulous application of the techniques described is a safe procedure. Daily monitoring of QRS amplitude in patients at home is an excellent safeguard against overlooking significant rejection episodes. This is of special importance in infants and children, in whom routine endomyocardial biopsy cannot be performed. Distant overnight monitoring minimizes psychosocial disturbance during follow-up after heart transplantation.

Adolescent↗
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Urodilatin, a new therapy to prevent kidney failure after heart transplantation.

Kidney failure after heart transplantation still remains a crucial problem, especially when cyclosporine is used for early postoperative immunosuppressive therapy. To preserve good renal function during immunosuppression with cyclosporine, urodilatin (CDD/ANP-95-126), the kidney-born analogue to the circulating cardiac peptide hANP (CDD/ANP-99-126), was given for the first time as a long-term, low-dose infusion in addition to the usual drug therapy immediately after heart transplantation. From November 1990 to January 1992, 47 patients (44 men and three women; mean age, 51 years) were treated by a 20 ng/kg body weight/min infusion for 96 hours after heart transplantation. Renal function and hemodynamic parameters of these patients were compared with a group of 40 patients (34 male and six female; mean age, 50 years) as controls, who underwent heart transplantation from May 1990 to November 1991. Both groups did not differ significantly with respect to age, sex, indication for heart transplantation, and preoperative renal function. With urodilatin treatment, renal function was significantly improved with lower peak plasma creatinine (1.83 +/- 0.1 versus 2.47 +/- 0.19 mg/dl; p = 0.003), lower peak serum urea (118 +/- 7 versus 178.3 +/- 10.3 mg/dl; p = 0.0036) and absence of hemodialysis (0% versus 10%; p = 0.026). Additionally, adequate diuresis was maintained although furosemide was reduced by more than 50% (p = 0.005) on each day of urodilatin treatment. Mean central venous pressure was significantly lower (-2 mm Hg; p = 0.02) during application of urodilatin, despite reduction of vasodilator therapy with nitroglycerin by about 50% (p = 0.02). Because of the significantly improved renal function and beneficial hemodynamic effects, the recommendation is therefore to introduce urodilatin in the postoperative treatment protocol after heart transplantation.

Adult↗
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Dynamic change in the left ventricular base with or without a rigid mitral valve prosthesis.

To evaluate the narrowing of the left ventricular outflow tract (LVOT) during systole caused by a rigid mitral prosthesis, the geometric relationship between the prosthesis (or the mitral annulus) and the left ventricular base (LVB) was studied in five patients with mechanical mitral valve prostheses and eight normal subjects. The images of the mitral valve annulus (MVA) and the LVOT orifice reconstructed in three dimensions were projected on the plane of the LV base. Calculating the areas of these projected images (i.e., those for MVA [Sm], LVOT orifice [So], the LVB [Sb; Sb = Sm + So]), the MVA-LVB ratio (Sm/Sb) was determined. In the normal subject, the MVA-LVB ratio was nearly constant during systole (59 +/- 5% at 0 msec and 62 +/- 7% at 300 msec, respectively), whereas in the patients with prostheses, the ratio increased from 61 +/- 4% (0 msec) to 69 +/- 4% (300 msec). The increase in MVA-LVB ratio reduces the proportionate share of LVOT orifice in relation to the total LVB. The ideal mitral valve prosthesis should be flexible at the annulus to attain good performance in LVB dynamics.

Adult↗
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Heparin induced thrombocytopenia. Experiences in 12 heart surgery patients.

A heparin induced thrombocytopenia Type II (HIT) is a dangerous complication of heparin therapy. Bleeding, but above all serious thromboembolic complications, which may result in crippling disabilities or even death, can develop. Twelve heart surgery patients who were diagnosed with a HIT Type II are reported. Seven of the patients were diagnosed post operatively, the other five pre-operatively. Two of these patients underwent heart surgery with r-Hirudin (Behringwerke AG, Marburg, Germany) on cardiopulmonary bypass and two on Orgaran (AKZO Organon, the Netherlands). Of the seven post operative HIT patients, four had had a bypass operation and each had received a mitral or aortic valve replacement. Another patient had received an artificial biventricular support system (Berlin Heart) and was diagnosed with HIT Type II post operatively. Because of his special condition, this patient underwent anticoagulation with Orgaran and heart transplantation with Orgaran on a heart lung machine. Upon suspicion of HIT Type II, heparin therapy was immediately halted and an alternative treatment of Orgaran or r-Hirudin was begun. One patient encountered bleeding of a gastric ulcer on Orgaran therapy. Heart surgery patients, especially patients with an artificial support system, are potentially lethally threatened by serious thromboembolic complications accompanying HIT Type II. Therefore, these patients must be diagnosed as early as possible. Orgaran along with r-Hirudin are effective heparin substitutes in patients with HIT Type II. These medications can be widely administered to heart surgery patients pre-, intra-, and post operatively without complication.

Adult↗