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Biomedical subjects

H G Borst

Publications and source records attributed to H G Borst.

At least 91 records · Page 5Linked to original sources
PubMed1992

[Progress in surgery of the aortic arch].

We summarize our experience out of 133 operations involving the aortic arch which were performed in 130 patients throughout the last 13 years. Aortic pathology was aneurysmal disease in 57 cases, acute aortic dissection in 44, and chronic aortic dissection in 29 patients. Operative strategies included partial replacement or repair of the aortic arch in 80 cases and subtotal or total replacement of the transverse arch in 53 patients. In 19 cases presenting with aneurysms of the descending thoracic aorta, implantation of an elephant trunk prothesis was performed simultaneously. The operations were performed during circulatory arrest (10-64 min, mean: 27 min) and in deep hypothermia (nasopharyngeal temperature: 11-25 degrees C). Recently, two modifications of the technique were introduced: First, the site of arterial inflow cannulation is changed by intubating the prothesis directly during reperfusion providing antegrade perfusion. Second, in patients with acute aortic dissection, the false lumen of the aortic root and arch is filled with resorcinformol glue and the layers are readapted by this means after anatomical reconstruction. Overall, early mortality was 14.3% and was much higher in acute dissection (22.7%) when compared to chronic dissection (6.9%, p = 0.110). A total of 24 reoperations were necessary in 16 patients of this group with subsequent replacement of the descending thoracic aorta being most frequently performed (n = 14). Actuarial survival after 5 years was not significantly different between the groups (69.1%) but showed a progressive decline for patients with aneurysms and chronic dissection (11 late deaths) while no late deaths occurred in acute dissections.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Future horizons of lung preservation by application of a platelet-activating factor antagonist compared with current clinical standards. Euro-Collins flush perfusion versus donor core cooling.

With the introduction of platelet-activating factor antagonists, a direct inhibition of ischemia-induced reperfusion injury can be achieved by prevention of platelet activation, reduction of microvascular leakage, and platelet-activating factor-induced bronchoconstriction. At present, two preservation methods are established for clinical lung preservation: (1) donor core cooling by extracorporeal circulation and (2) pulmonary artery flush with Euro-Collins solution and prostacyclin. We compared the quality of organ preservation obtained with these methods to the application of a platelet-activating factor antagonist (WEB 2170; 0.3 mg/kg) for the donor, perfusion solution, and throughout the first 6 hours of reperfusion in combination with prostacyclin (20 ng/kg/min) and Euro-Collins solution (60 ml/kg). Eighteen heterotopic heart and orthotopic left lung transplants were performed in three groups of six dogs each after 6 hours of cold ischemia (group I, donor core cooling; group II, Euro-Collins flush and prostacyclin; group III, Euro-Collins flush, prostacyclin, and WEB 2170). Myocardial preservation was achieved with St. Thomas' Hospital solution (20 ml/kg) in all groups. After transplantation, cardiorespiratory function was assessed at an inspired oxygen fraction of 0.4. After transplantation, superior results were observed in group III, as expressed by significantly improved oxygenation, while cardiac output and pulmonary artery pressures were similar in all groups. We concluded that the use of the platelet-activating factor antagonist WEB 2170 resulted in better lung preservation than current clinical standards.

Animals↗
PubMed1991

Fulminant pulmonary embolism: symptoms, diagnostics, operative technique, and results.

Fulminant pulmonary embolism associated with cardiac arrest has an extremely high mortality. The feasibility of pulmonary embolectomy initiated during resuscitation is still under discussion. Between January 1975 and January 1991, pulmonary embolectomy was performed in 27 patients, 21 to 79 years old. The diagnosis was established primarily by clinical findings in 18 patients, by angiography and ventilation-perfusion mismatch in 4 patients, and by transesophageal echocardiography in 1 patient seen recently. Eleven patients did not require resuscitation (group 1); 5 patients had to be resuscitated and underwent operation after circulation was reestablished without need of further cardiac massage (group 2); and 11 patients were connected to extracorporeal circulation devices during cardiopulmonary resuscitation (30 to 210 minutes) (group 3). Embolectomy was performed using extracorporeal circulation with the heart beating (n = 2) or fibrillating (n = 15) or using cardioplegia (n = 10). Fifteen patients received a caval clip or ligature at the end of the procedure. Twelve patients died early postoperatively; the mortality rates were 36%, 60%, and 45% for groups 1, 2, and 3, respectively. Eight patients died of right heart failure, and 2 patients each died of brain death and sepsis. Of the surviving patients, only 1 showed ischemic brain damage. Mean stay in the intensive care unit was 5.1, 7.0, and 9.75 days for groups 1, 2, and 3, respectively. There were no recurrent embolisms during the 15-year follow-up (mean follow-up, 4.6 years). This experience demonstrates that even with subtotal obstruction of the pulmonary arteries, effective cardiopulmonary resuscitation with maintenance of uncompromised brain function is possible.(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiopulmonary Resuscitation↗
PubMed1991

Extracorporeal membrane oxygenation as a bridge to lung transplantation.

The occurrence of severe graft failure after lung transplantation which appears refractory to conventional treatment represents a difficult situation with regard to the therapeutic strategies available. Of 17 patients undergoing single lung transplantation at our center, 2 developed early graft failure. In both, temporary artificial cardiopulmonary support by means of extracorporeal membrane oxygenation became necessary as a bridge to retransplantation. Both patients were successfully retransplanted after 8 h and 232 h, respectively, of extra-corporeal support. Postoperatively, there was a variety of complications. The first patient completely recovered from temporary severe cerebral dysfunction diagnosed as "locked-in syndrome". She was discharged from hospital on the 93rd postoperative day and remains alive and well 10 months after her operation. The other patient recovered well early after retransplantation. Later, however, airway problems developed, requiring the implantation of endotracheal stents. Cachexia and several episodes of viral pneumonia contributed to the progressive deterioration of her clinical status. She finally died after being hospitalized for 5 months after the original operation. These two cases illustrate the feasibility of using extracorporeal membrane oxygenation as a bridge to pulmonary transplantation.

Adult↗
PubMed1991

Tumor-related obstruction of the inferior vena cava extending into the right heart--a plea for surgery in deep hypothermic circulatory arrest.

This study reviews eight patients, 39-63 years old, with tumor-related obstruction of the inferior vena cava (IVC) extending into the right atrium (n = 5) and ventricle (n = 3). Five patients suffered from renal cell carcinoma, 3 from sarcomatous disease. The general approach was a median sternotomy and laparotomy with hypothermic circulatory arrest (17.0-20.5 degrees C; 23-46 min) in six patients, while in two patients, the IVC was clamped sequentially under moderate hypothermia and extracorporeal circulation. Four patients had tumor infiltration of the IVC necessitating partial caval resection. In three, the IVC was reconstructed by fabric patches or tubular prothesis. In one patient, the continuity of the IVC was interrupted permanently. Three patients underwent nephrectomy during the same procedure, two before and one after IVC disobliteration. In one patient each, pulmonary embolectomy and intrahepatic IVC stenting were performed. Two patients died early, one due to uncontrollable hemorrhage the other due to non-cardiogenic pulmonary edema. Six patients were discharged in good physical condition and are still alive at a mean follow-up of 24 months. Five patients have since remained free of recurrence, one patient underwent three further surgical interventions for bone metastases. We feel that IVC desobliteration is feasible in selected cases with extended tumor-related obstruction with an acceptable early risk and late outcome.

Adult↗
PubMed1991

Hyperacute rejection in heart allografts. Case studies.

Hyperacute rejection in orthotopic heart allografts is a rare event. In our material from a total collective of 524 heart-transplanted patients, we have observed two cases of hyperacute rejection, which are presented in this case report. Histopathologically, this entity is characterized above all by the following triad: pronounced edema, hemorrhages, and regressive changes up to necroses of myocytes. Besides the well-known risk factors, our report draws attention to two further factors possibly associated with an increased risk of hyperacute rejection: 1) repeated cardiac surgery prior to the transplantation, and 2) presence of identical viral genomes in recipient's and donor's heart.

Adult↗
PubMed1991

Extracorporeal membrane oxygenation (ECMO): extended indications for artificial support of both heart and lungs.

Extracorporeal membrane oxygenation (ECMO) was used to achieve temporary artificial support in cardiac and pulmonary function in 22 patients from 1987 to September 1990. Standard indications were postcardiotomy cardiogenic shock (n = 4), neonatal (n = 1) and adult respiratory distress syndrome (n = 4). ECMO was also used for extended indications, such as graft failure following heart (n = 11) or lung transplantation (n = 2). In six of these cases ECMO was instituted as a bridge device to subsequent retransplantation of either the heart (n = 4) or one lung (n = 2). One out of nine patients supported by ECMO for standard indications, and two out of 13 patients supported for extended indications are long-term survivors. This series illustrates the results with ECMO in emergency situations, in patients under immunosuppressive protocols, or in patients with advanced lung failure requiring almost complete artificial gas exchange. In such complex situations, ECMO does provide stabilization until additional therapeutic measures are in effect. ECMO cannot be recommended for postoperative cardiogenic shock but short-term ECMO support is an accepted method in most cases with graft failure or pulmonary failure or other origin.

Adult↗
PubMed1991

Management of thoracoabdominal malperfusion in aortic dissection.

Malperfusion of the thoracoabdominal aorta or its branches is a common complication of aortic dissection, often with a fatal outcome. Since 1985 we saw thoracoabdominal malperfusion in 13 patients with aortic dissection. During repair of an acute type A aortic dissection, the intimal flap was fenestrated in three cases in the abdominal aorta and one within the superior mesenteric artery. In two cases with acute type B aortic dissection fenestration was performed at the level of the aortic bifurcation, and in one the descending aorta was replaced. Six patients had chronic dilatation of a false lumen without distal reentry, compromising the true lumen, with malperfusion of viscera, kidneys, and lower extremities. Three patients underwent replacement of the descending aorta, two of them subsequent abdominal aortic replacement with revascularization of the kidneys. One patient had thoracoabdominal replacement, and in two an extra-anatomic bypass was implanted. Five patients with acute dissection died: two from sequelae of malperfusion, two of myocardial failure, and one late after stroke. Eight patients are alive 1 month to 5 years after operation. In acute aortic dissection fenestration of the intimal flap may relieve thoracoabdominal malperfusion. In chronic aortic dissection, pseudocoarctation is most likely to occur at the diaphragmatic hiatus. This is treated by replacement of the affected aortic segment. In high-risk patients an extra-anatomic bypass is also feasible.

Aortic Dissection↗
PubMed1991

Surgery extended into the aortic arch in acute type A dissection. Indications, techniques, and results.

From May of 1979 to September of 1990, 106 patients underwent emergency surgery for acute type A aortic dissection. In 29 patients (27.3% of total; mean age, 53 years) surgery was extended into the aortic arch. In 19 cases the proximal entry reached or began beyond the aortic cross-clamping site, which prevented proper reconstruction of the distal aorta. In six cases an aortic perforation was located in the arch. In four others the dissection occurred within a preexistent arch aneurysm. Operative techniques consisted of eight arch reconstructions, 17 proximal arch replacements, and four total arch replacements. Repair was performed during deep hypothermia (mean nasopharyngeal temperature, 17.8 degrees C) and circulatory arrest (mean, 24.2 minutes). Operative mortality was 20.6% (six of 29), dropping to 10.5% (two of 19) during the past 4 years. There were no late deaths in the 23 survivors, with one patient suffering from neurological sequelae. Nineteen underwent either computed tomography and digital subtraction angiography or magnetic resonance imaging without pathological findings in the ascending aorta or arch. In acute type A aortic dissection the site of the intimal tear and/or perforation, as well as preexistent aneurysmatic disease, may require primary aortic arch repair. This can be accomplished during deep hypothermia and circulatory arrest, with acceptable early and satisfactory late results.

Aortic Dissection↗
PubMed1990

Thoracic aortic aneurysms after acute type A aortic dissection: necessity for follow-up.

Between April 1979 and May 1989, 86 patients underwent emergency operation for acute type A aortic dissection. Sixty-four (74.4%) survived. None of the survivors died of late aortic complications. Fifty-eight patients were followed 3 months to 10 years (mean follow-up, 3.2 years) postoperatively with computed tomography and digital subtraction angiography. Dilatation of the distal aorta (diameter size range, 6 to 10.5 cm) developed in 10 patients (17%). Six patients underwent replacement of the descending aorta 1 month to 21 months (mean period, 8.5 months) after aortic dissection repair. Two of them had third-stage thoracoabdominal replacement. In 2 patients, replacement of the descending aorta was scheduled; 1 died before reoperation and 1 refused the procedure. Two patients underwent aortic arch replacement; it is scheduled for another (fourth stage). There were no deaths among the patients having reoperation. The rate of indications for reoperation on the aorta downstream from the original repair 1 month to 6 years 4 months (median time, 9 months) after primary surgical intervention for acute type A aortic dissection was 24% (14 reoperations in 10 of 58 patients). This study underscores the importance of close follow-up of patients having operation for acute type A aortic dissection. Early recognition of progressive downstream aortic pathology permits effective prevention of aortic rupture and timely reoperation.

Adult↗
PubMed1990

Coarctation of the aorta in complex congenital heart disease: simultaneous repair via sternotomy.

Coarctation of the aorta (CoA) is often associated with complex congenital heart disease. Patients with such a combination may not benefit from coarctectomy alone. Eight children who presented with complex malformations of the heart underwent simultaneous repair of CoA and intracardiac surgery via sternotomy. After extensive mobilization of the aortic arch, cardiopulmonary bypass was established. During the cooling phase for deep hypothermic circulatory arrest (six cases), a persistent temperature gradient between the upper and lower half of the body confirmed the significance of CoA. One child was operated upon in deep hypothermia with low flow and one underwent valve repair on cardiopulmonary bypass. Mobilization of the descending aorta enabled CoA resection and end-to-end anastomosis with a running absorbable suture. The average descending aortic cross-clamping time was 15 min. By this time, the patient had been cooled sufficiently for the intracardiac procedure. There were two operative deaths not related to coarctectomy. The remaining children showed no arm-to-leg pressure gradient. Five were discharged from hospital and one patient died late from septicaemia. In our hands, this technique has served to accomplish simultaneous relief of CoA and repair of the intracardiac lesion thus sparing critically ill infants the hazards of repeated procedures.

Aorta, Thoracic↗
PubMed1990

Distant organ procurement in clinical lung- and heart-lung transplantation. Cooling by extracorporeal circulation or hypothermic flush.

The scarcity of suitable donors for single lung and heart-lung transplantation calls for methods of medium-term pulmonary preservation to allow for distant organ procurement. At our institution, the first five grafts (four heart-lung, one single lung) were cooled by means of a transportable extracorporeal circulation unit, while the last eight grafts (four heart-lung, four single lung) were flush-perfused with modified cold Euro-Collins solution. The technique of extracorporated circulation included aortic and right atrial cannulation and cooling to 12 degrees-14 degrees C (rectal temperature) using a bubble oxygenator. Bypass times ranged between 41 and 52 min. Following excision, the organs were transported in ice-cold donor blood for ischemic times from 171 to 310 min. For cold flush preservation, simultaneous coronary (cold St. Thomas's solution) and pulmonary artery perfusion (Euro-Collins solution, 50 ml/kg over 4 min) were initiated simultaneously. The organs were transported in cold Euro-Collins solution for ischemic times of 175 to 270 min. In heart-lung transplantations the first postoperative arterial PO2 upon arrival at the intensive care unit was 120 +/- 38 Torr in the extracorporeal circulation and 140 +/- 38 Torr in the Euro-Collins solution group. Six of eight patients were extubated within 48 h after cardiopulmonary grafting. We conclude that pulmonary function following heart-lung or single lung preservation with simple hypothermic flush is as good or better than that following extracorporeal circulation. Since distant organ retrieval is much more convenient without the latter, preservation using Euro-Collins solution is preferred.

Adolescent↗
PubMed1990

Heart transplantation: intraoperative management, postoperative therapy and complications.

Currently, heart transplantation (HTX) is performed as an orthotopic cardiac replacement according to the technique of Lower and Shumway in over 95% of the cases with good results. Survival after heterotopic HTX, by contrast, remain poor (one year survival: 50%). Postoperative therapy compiles primarily prophylactic measures to prevent complications, especially organ rejection and infections. Immunosuppressive prophylaxis generally includes a triple drug therapy consisting of cyclosporin, prednisolone, and azathioprine for maintenance therapy. Initially there is often an additional application of poly- or monoclonal antibodies. The prime measure to prevent infection during the initial hospital stay will be reversed isolation of the recipient. Initial antibiotic prophylaxis resembles that of conservative cardiac surgery, but in addition antiviral and antifungal prophylaxis is applied. The most common postoperative complication following HTX is cardiac rejection, which is detected by routine endomyocardial biopsies. At our institution the incidence of rejection decreases from 3.07 episodes per patient in the first 3 months to 1.97 episodes during the last 6 months of the first year after HTX. In general, acute rejection is treated by methylprednisolone (3 x 500 mg/day) or anti-T-cell-antibodies. Infections often occur following intervals of increased immunosuppression, usually early postoperatively and following therapy of acute rejections. Often, invasive diagnostic measures have to be taken rapidly in order to allow for specific therapy (antibiotics, antimycotic treatment, virostatic agents). Close follow-up of the heart transplant recipient and rapid therapy of possible postoperative complications enable the current one-year survival rates of 80% or more.

Anesthesia↗