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Biomedical subjects

R Hetzer

Publications and source records attributed to R Hetzer.

At least 415 records · Page 23Linked to original sources
PubMed1979

Thermocardiography--a method for continuous assessment of myocardial perfusion dynamics in the exposed animal and human heart.

In the exposed animal and human heart, coronary flow reduction results in a significant decrease of regional myocardial temperature. Epicardial temperature can be recorded instantaneously by the use of thermography. In contrast to other techniques, this method allows continuous assessment of rapid coronary flow changes and shows exactly the extent of myocardium involved. Value and limits of thermocardiography in animal experiments and during coronary bypass surgery are discussed and typical examples of myocardial thermograms obtained at various interventions are shown.

Animals↗
PubMed1978

Thrombosis and degeneration of Hancock valves: clinical and pathological findings.

Of 415 Hancock valves implanted in 370 patients, 26 valve specimens were recovered at postmortem examination and 8 at reoperation. In 9 of these 34, thrombosis had formed without apparent alteration of the heterograft tissue (Group A). All were mitral prostheses, and the thrombi were attached to the sewing ring. Six of the patients died in the early postoperative period following prolonged low cardiac output syndrome and coagulation disturbances. Three patients had late valve thrombosis 12 to 26 months after operation and were in chronic atrial fibrillation with a very large left atrium. Four valve specimens (Group B) demonstrated degenerative changes of the heterograft leaflets such as shrinkage, perforation, and calcification. The clinical courses and possible pathogenesis are discussed.

Aged↗
PubMed1978

Surgery of tumors of the subdiaphragmatic inferior vena cava. Report of two cases and review of the literature.

Two cases of obstruction of the hepatic inferior vena cava (IVC) are presented. In Case 1, the obstruction was due to a calcified thrombus which presumably developed after lower limb trauma 19 months previously. Complete surgical correction was achieved with the aid of deep hypothermia and circulatory arrest. In Case 2, a right atrial tumor was mimicked by a propagating malignant hepatoma. Palliative removal of the tumor cleared the IVC passage. The etiology of tumors of the IVC and their surgical management are discussed.

Aged↗
PubMed1978

Thromboembolic complications after mitral valve replacement with Hancock xenograft.

Case histories of 140 patients who had mitral valve replacement with the Hancock xenograft were reviewed according to the incidence of thromboembolic complications. There were 16 patients with preoperative and/or postoperative low-output syndrome (Group A.) Eight of these patients died, and six had autopsies which showed major thrombi on the heterograft valve. In 126 long-term survivors (followed 1 to 33 months) nine thromboembolic events occurred (thromboembolic incidence 5.3 percent per patient-year). All patients with emboli were in atrial fibrillation. Additional predisposing factors included a history of systemic emboli and the presence of atrial clots at the time of surgery. The majority (7/9) of emboli occurred during the first 3 postoperative months. Two emboli occurred immediately following the operation (before oral anticoagulation therapy could have been begun). Five occurred in patients who were not on anticoagulation (Group B) and two occurred under warfarin treatment (Group C). There was no thromboembolic event in patients taking aspirin (Group D). It is concluded that hemodynamically stable patients have a decreased risk of thromboembolism and do not require anticoagulation. Patients with atrial fibrillation have an increased thromboembolic risk and should be on a regimen of warfarin for 3 months postoperatively and then on aspirin therapy.

Adolescent↗
PubMed1976

[Cineradiographical studies of local ventricular motility before and after aorto-coronary bypass (author's transl)].

The purpose of this study was to observe the effect of surgical revascularization on the motility of the left ventricular segment distal to a high grade coronary stenosis. In 17 patients with LAD bypass local relative segment shortening lambda (lambda = diastolic length - systolic length/diastolic length X 100) was determined measuring the distances of coronary bifurcations and surgically implanted myocardial metal markers frame by frame in high speed cineradiography. A group of 14 patients whose angina pectoris was abolished after operation and where bypass proved to be patent showed significant increase of lambda within the first postoperative days (lambda preop. = 3,4 +/- 18,3 SD, lambda postop. = 18,9 +/- 8,0 SD, p less than 0.05). Paradoxical movement had disappeared in 4 cases. In the following two-monthly controls up to one year no significant further alterations of local motility were seen. Three patients with persisting angina did not show any increase of segment shortening. It is concluded that aorto-coronary bypass surgery can restore impaired local motility in the majority of patients. The method described is useful for repeated non-invasive controls of the success of operation.

Angina Pectoris↗
PubMed1976

[Studies on the local motility and blood circulation of the heart muscle during and after long-term coronary strangulation].

In ten young pigs a severe prolonged and critical stenosis of a major coronary artery was produced under control of an electromagnetic flowmeter. With stepwise constriction flow could be reduced to 55% of control with only minor hemodynamic changes. Local myocardial segment shortening was depressed to approximately 30% of control values. Hypokinesis was partially reversible within the first 135 min after reperfusion and had disappeared 24 h later. Computerized perfusion scintigraphy with radioactive microspheres gives a reliable approximation of the degree of myocardial blood flow reduction.

Animals↗
PubMed1976

[X-ray cinematographic studies of local ventricular dynamics after aortocoronary bypass].

In 12 patients with high-grade coronary stenosis local motility before and after aortocoronary vein bypass was estimated by cineradiography of coronary bifurcations and surgically implanted myocardial metal markers. A group of patients with relief of angina showed significant increase of local segment shortening within the first postoperative days. During the following months no further alteration occurred. In three patients with persisting angina no improvement of local motility could be found.

Cineradiography↗
PubMed1975

[Heart valve surgery in bacterial endocarditis (author's transl)].

Bacterial endocarditis was the cause of heart valve destruction in 23 patients. Additional 5 patients were reoperated because of an infected valve prothesis. 13 were operated upon during the inactive stage. Nevertheless infection recurred after operation at least in one patient. 10 patients underwent operation during the active stage, 6 of these with stable cardiac function, 4 in cardiogenic shock. Hospital mortality was 2/6 and 1/4 respectively. One patient died after three months of persisting infection. Three of five patients with infected valve prosthesis survived reoperation. An attempt is made to define the indication for valve surgery in bacterial endocarditis.

Adolescent↗
PubMed1975

Complications of permanent transvenous cardiac pacing.

Clinical experience with permanent transvenous pacing during a 6 year period at Hannover Medical School is presented. A total of 1,376 pacemaker operations were performed in 799 patients, with a mortality rate of 1.1 per cent. The most common complications were premature battery failure, dislocation of endocardial electrodes, infections of the generator and/or electrodes, and skin ulcerations. In our cumulative follow-up period of 1,225 years, a complication necessitating a reoperation is to be expected after an average function-time of 31 months. Including normal battery exhaustion in this calculation will make reoperation necessary every 21.9 months.

Adult↗
PubMed1975

[Prevention of thrombosis using acetylsalicylic acid following vascular prosthesis and endarterectomy].

In 20 dogs one common iliac artery was intimectomized, an equal segment of the other was replaced by a knitted dacron prosthesis. Ten animals were given Acetylsalicylic Acid 30 mg/kg BW/d. Four weeks later these arterial segments were examined grossly and histologically for the presence of thrombotic depositis. In the treated animals these segments always remained patent. Three of the untreated animals showed a complete thrombotic occlusion of the prosthesis. The amount of thrombotic deposits on intimectomized and prosthetics segments was clearly reduced in the treated animals.

Animals↗