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Biomedical subjects

F W Hehrlein

Publications and source records attributed to F W Hehrlein.

At least 55 records · Page 3Linked to original sources

Aortic arch replacement by posterolateral exposure.

Aortic arch replacement was carried out in a 54 year old male patient with an unexpected type A-dissection, using partial femoro-femoral bypass and hypothermic arrest, through a left side posterolateral thoracotomy. After the replacement of the aortic arch from the ascending to the descending aorta a warm-up perfusion was done through an 8 mm side arm Dacron prosthesis attached to the descending segment of the 30 mm Dacron graft. This technique was demonstrated to be safe and protective in our patient and can be used as an alternative surgical method in the treatment of aortic arch dissection or aneurysms of the transverse aortic arch.

Aortic Dissection↗

Laser-assisted trachea anastomoses in dogs.

Tracheal anastomoses are known to be related to special surgical risks. We performed laser-assisted trachea anastomoses in 10 Beagle dogs, using an Argon-laser system and a handheld quarz fiber for energy transmission. All animals showed an uneventful postoperative course without signs of infection, air-leakage or respiratory impairment. Pathologic examination revealed no significant stenosis but a normal reconstruction of the tracheal endothelium and a normal woundhealing with only an increased connective tissue reaction. Because of the lower tensile strength of laser-assisted anastomoses in general, three adapting absorbable sutures should be left in situ to increase the resistance against mechanical stress. Under these circumstances laser-assisted anastomoses seem to be a promising additional method in the field of tracheal reconstruction and transplantation.

Anastomosis, Surgical↗

PTFE grafts to the right coronary artery following endarterectomy.

In ten of 3031 patients undergoing coronary surgery, we used a PTFE graft for bypass to the right coronary artery following endarterectomy. Diffuse calcification was the reason for endarterectomy of the right coronary artery in all cases. We chose a PTFE graft only in those cases where autologous grafts were not available in a sufficient number. After a mean follow-up period of twelve months nine of the ten grafts were patent.--This study demonstrates that under selected circumstances PTFE grafts can be successfully used in coronary surgery if autologous grafts are lacking.

Blood Vessel Prosthesis↗

Myocardial protection of hypertrophied hearts by administration of cardioplegia according to regional myocardial temperature.

Hypertrophied hearts are known to be extremely vulnerable to ischemia. During cardioplegic arrest different regional myocardial temperature are known to occur. We investigated myocardial protection in 61 patients with aortic valve disease undergoing aortic valve replacement. Three different cardioplegic solutions were used. Regional myocardial temperature was continuously controlled and adjusted to a temperature of not more than 15 degrees C by intermittend infusion of cardioplegia. Before, after heart arrest and after 10 minutes of reperfusion we did myocardial biopsies and determined high energy phosphates and lactate. From our results we conclude that three cardioplegic solutions were able to protect hypertrophied hearts adequate during an ischemic period of 60 minutes if the regional myocardial temperature does not increase above 15 degrees C.

Body Temperature↗

Ultrastructure of the human myocardium after intermittent ischemia compared to cardioplegia.

A lot of reports informed about the detrimental effects of intermittent ischemia nevertheless this method is still used during coronary surgery. We investigated the myocardial protection due to cardioplegic arrest compared to intermittent ischemia in 120 patients undergoing coronary surgery. In all patients we took myocardial biopsies from the left ventricle before and after ischemia. Electron microscopic studies of all biopsies were performed and the degree of ultrastructural alteration was determined. The ischemic period in the cardioplegic group was 61 +/- 15 minutes and in the group with intermittent ischemia the total ischemic time was 45 +/- 21 minutes. After ischemia the myocardium showed most time only damage of moderate or light degree, while after intermittent ischemia the most biopsies showed severe ultrastructural damage. From our results we conclude, that intermittent ischemia is unable to protect the myocardium in a sufficient amount and should therefore no longer be used as a method of myocardial protection.

Biopsy↗

[Penetrating heart injuries].

Penetrating cardiac injuries provide the surgeon until nowadays with a challenging problem due to a high mortality rate. Depending on the mechanism of trauma and the time interval less than 20% of the patients with severe wounds of the heart reach the hospital alive. Methods of managing these wounds are controversial. Pericardiocentesis has more a diagnostic than a therapeutic value. Emergency thoracotomy will help reduce the mortality even in agonal and decompensation patients. With respect to the literature and 31 own cases the diagnosis, the operative management and the results will be discussed.

Cardiac Tamponade↗

Incidence and pathogenesis of late aneurysms after patch graft aortoplasty for coarctation.

From 1957 to 1984 direct and indirect isthmoplasty as described by Vossschulte has been the method of choice for surgical therapy of coarctation of the aorta in our hospital. A total of 317 patients have been so treated, 54 of whom were less than 12 months old at operation. The hospital mortality in this group was 15% and the mortality in patients older than 1 year was 3%. The early results were encouraging, but during follow-up an increasing number of postoperative aneurysms have been detected. During reinvestigation an aneurysm was diagnosed in 18 cases. Therefore, we have studied the cause of these aneurysms. To this point reoperation has been performed in 15 patients having late aneurysms. Extensive resection of a fibrous membrane of the aortic isthmus at the first intervention seems to be an essential predisposing factor for development of aneurysms. Microscopic examination of the aneurysmal wall revealed degeneration of the media in more than half of the patients. From our experience we conclude that the posterior fibrous ridge should no longer be excised and the Vossschulte operative technique should be viewed more critically.

Adolescent↗

Combined therapy of re-coarctation of the aorta and coronary heart disease.

We report on an uncommon case of recoarctation of the aorta 36 years after resection and end-to-end anastomosis associated with coronary heart disease. Since a two-staged surgical therapy implies an increased risk of life for the patient, we decided to perform a combined surgical procedure. Exposing the heart by a median sternotomy we implanted a 16 mm synthetic graft from the ascending to the descending thoracic aorta and performed a prosthesio-coronary bypass in one session. The patient had an uneventful recovery. In our opinion this procedure is the method of choice for similar cases.

Adult↗

Protection of the hypertrophied human heart by adjusting regional myocardial temperature to a safe level.

Uneven distribution of temperature and the persistence of electro-mechanical activity after aortic cross-clamping are 2 factors limiting the myocardial protection during cardioplegic arrest, especially in hypertrophied hearts which are known to be extremely vulnerable to ischemia. In the present study regional myocardial temperature (T) was continuously controlled, and the time until arrest occurred (delta t) was determined in 61 patients undergoing aortic valve replacement. In addition, the myocardial contents of high energy phosphates and lactate were assessed. Three different cardioplegic solutions were employed: In the first group we used Bretschneider solution (Br), in the second group St. Thomas' solution (St), and in the third group the so-called "Hamburg cardioplegia" (H). During cardiac arrest the regional myocardial temperature was adjusted to temperatures not exceeding 15 degrees C by intermittent infusions of cold cardioplegic solution. We found a positive correlation between left ventricular muscle mass (LVMM) and delta t. A negative correlation existed between LVMM and adenosine triphosphate (ATP) contents at the end of the ischemic period. The cooling characteristics and delta t were significantly longer and the cooling to 15 degrees C was less rapid when H was used. Adenosine-triphosphate contents were well preserved during ischemia in all 3 groups. We conclude that all 3 cardioplegic solutions tested protect the hypertrophied myocardium adequately if the regional myocardial temperature does not increase above 15 degrees C during cardiac arrest. Hearts with a higher LVMM showed a decreased myocardial ATP content at the end of the ischemic period. Therefore, the LVMM may limit myocardial protection.

Adenosine Triphosphate↗

Intraoperative somatosensory evoked potentials as a prognostic factor of neurologic state after carotid endarterectomy.

Somatosensory evoked cervical and cortical potentials (SEP) were analyzed under general anesthesia in 106 patients undergoing carotid endarterectomy. Cortical electrical silence occurred in 5 patients without an inlying shunt; all developed a new neurologic deficit postoperatively. Analysis of the SEP in these patients revealed progredient cerebral ischemia as indicated by an increase in central conduction time (CCT) and a decrease in amplitude of the primary cortical response N20P25 resulting in a complete loss of cortical SEP later on during the clamping period. In 6 patients the insertion of a shunt restored the deteriorated SEP, these patients and those with unchanged SEP after carotid clamping showed an uneventful postoperative recovery. Taking the presence or absence of N20P25 as the sole parameter, the sensitivity of this technique was 83%, specificity 99% and predictability 83%. A normal range for CCT and amplitude of N20P25 during anesthesia and criteria for shunt insertion were developed. The presented monitoring regimen appears to be rational and is based on current concepts of cerebrovascular physiology and pathophysiology.

Adult↗

Effects of prostacyclin during cardiopulmonary bypass in men on plasma levels of beta-thromboglobulin, platelet factor 4, thromboxane B2, 6-keto-prostaglandin F1 alpha and heparin.

A randomized double-blind study was carried out on 40 male patients requiring aorto-coronary bypass surgery. 20 patients received a constant dose of 8 ng kg-1 min-1 of prostacyclin (PGI2), beginning two minutes before extracorporeal circulation (ECC) and ending together with ECC. Compared to the placebo-treated patient group (n = 20), PGI2-treatment significantly reduced the ECC-induced release of platelet alpha-granule proteins, beta-thromboglobulin (1178 ng/ml vs. 1926 ng/ml) and platelet factor 4 (837 ng/ml vs. 1245 ng/ml) into plasma (mean of max. values). Furthermore the decrease of platelet counts during ECC was less pronounced in PGI2-treated patients. Application of PGI2 had no effect on the increase in thromboxane B2 (TxB2) plasma levels, which amounted to 0.6 ng/ml at the end of ECC. PGI2-treatment resulted in significantly elevated plasma concentrations of 6-keto-prostaglandin F1 alpha (6-keto-PGF1 alpha) (2.1 ng/ml) throughout the infusion off prostacyclin. 6-keto-PGF1 alpha plasma levels increased up to 1.2 ng/ml in the control group patients, indicating a stimulation of endogenous PGI2 formation during ECC.

6-Ketoprostaglandin F1 alpha↗