P4799Long-term thromboembolic risk in patients with postoperative atrial fibrillation after left-sided heart valve surgery

Background

New-onset postoperative atrial fibrillation (POAF) is a common complication of cardiac surgery. However, data on the long-term risk of thromboembolism in patients who develop POAF after heart valve surgery are sparse. In addition, data on stroke prophylaxis in this setting are lacking.

Objective

To assess the long-term risk of thromboembolism in patients developing new-onset POAF following isolated left-sided heart valve surgery relative to patients with nonsurgical, nonvalvular atrial fibrillation (NVAF).

Methods

Using data from the Eastern Danish Heart Surgery Database and Danish nationwide registries, we identified patients who developed POAF following isolated left-sided heart valve surgery (i.e. biologic aortic/mitral valve replacement or aortic/mitral valve repair) from 2000 through 2015. These patients were matched with patients with nonsurgical NVAF in a 1:4 ratio by age, sex, heart failure, hypertension, diabetes, a history of thromboembolism, ischemic heart disease, and year of diagnosis. Long-term risk of thromboembolism was examined by the Aalen-Johansen estimator and cause-specific Cox regression models adjusted for comorbidities, concomitant pharmacotherapy, and oral anticoagulation therapy as a time-dependent covariate.

Results

A total of 1,539 patients undergoing isolated left-sided heart valve surgery were identified. Of these, 716 (46.5%) patients developed POAF after surgery. A total of 630 patients with POAF were matched with 2,520 patients with NVAF. In the matched study population, the median age was 71 years (25th-75th percentile 66–77 years) and 59.5% were men. Oral anticoagulation therapy was initiated within 30 days post-discharge in 62.7% and 51.4% of these patients, respectively. Compared with NVAF, POAF was not associated with a significantly different 5-year absolute risk of thromboembolism (10.7% [95% confidence interval [CI], 8.0%-13.9%] versus 8.9% [95% CI, 7.6%-10.2%] in the POAF and NVAF group, respectively) (Figure). In the adjusted analysis, the long-term risk of thromboembolism was similar in patients with POAF and NVAF (hazard ratio [HR] 1.01 [95% CI, 0.71–1.44]). Anticoagulation therapy during follow-up was associated with a lower risk of thromboembolic events in patients with POAF (HR 0.45 [95% CI, 0.18–0.99]) as well as NVAF (HR 0.58 [95% CI, 0.42–0.80]) compared with no anticoagulation therapy.

Conclusions

New-onset POAF following isolated left-sided heart valve surgery was associated with a similar long-term risk of thromboembolism compared with NVAF. Future studies addressing the role of oral anticoagulation therapy in POAF after heart valve surgery are warranted to examine the efficacy and safety as well as the timing and duration of anticoagulation therapy.

Bronchial arterial devascularization. An experimental study in pigs

OBJECTIVE

The lungs have dual blood supply: The bronchial and the pulmonary circulation. The importance of bronchial circulation is disputed. The purpose of this study was to establish an experimental model to examine the importance of the bronchial artery.

DESIGN

Comparative porcine experimental study. The surgical technique was evaluated in group A (n = 9). Group B (n = 8) underwent left bronchial arterial devascularization. In group C (n = 9) the left principal bronchus was devascularized, transsected, and reanastomosed. In groups B and C bronchial mucosal blood flow was studied with laser-Doppler velocimetry. Devascularization was controlled by angiography at section, and specimens were examined with conventional histology and scanning electron microscopy. The right bronchus served as control.

RESULTS

In group B devascularization caused considerable, yet insignificant reduction in bronchial mucosal blood flow index (p = 0.1282) postoperatively, and after 1 week (p = 0.0678), insignificant histologic (p > 0.2) changes, and no scanning electron microscopy differences. In group C devascularization with bronchial transsection caused significant reduction in mucosal blood flow index (p = 0.0277) postoperatively and after 1 week (p = 0.0277), significant histologic changes (p = 0.0277), and insignificant (p = 0.069) changes in scanning electron microscopy.

CONCLUSION

Bronchial arterial devascularization with transsection caused significant physiologic and morphologic changes, and a model with bronchial devascularization should include transsection.

Bronchial transsection and reanastomosis in pigs with and without bronchial arterial circulation

BACKGROUND

The bronchial artery may be vital to the bronchi and lung parenchyma, but results of lung transplantation have raised doubts. This study was performed to examine the effect of bronchial arterial devascularization on bronchial morphology after bronchial transsection and reanastomosis.

METHODS

In 6 pigs (study group), the left main bronchus was transsected, reanastomosed, and devascularized. Six control pigs had the same operation without devascularization. After 1 week, bronchial arterial angiography was performed, and specimens were examined with conventional histology and scanning electron microscopy.

RESULTS

Histology showed significant changes (inflammation, edema, and fibrosis) in bronchi and lung parenchyma of the study group compared with the unoperated side (p = 0.028) and with the control group (p = 0.050). Scanning electron microscopy showed significant ciliary denudation in the study group's left bronchus compared with the unoperated side (p = 0.043) and with the control group (p = 0.0071).

CONCLUSIONS

The loss of cilia of the bronchial epithelium and the occurrence of inflammation, edema, and fibrosis in bronchi and lung parenchyma 1 week postoperatively were significantly related to the absence of the bronchial arterial circulation.

[Circulatory support with the mechanical heart, "HeartMate"]

Treatment with the mechanical heart, HeartMate, has been introduced in Denmark. Short-term circulatory support can be obtained by intraaortic balloon counterpulsation, an external centrifugal pump and the total artificial heart. Long-term circulatory support can be established by treatment with the HeartMate. The principle of the mechanical heart is simple--a pump is implanted in parallel to the existing heart and connected to external, portable batteries. The patient quickly improves and is brought in an optimal state for transplantation. A few patients have been able to omit the subsequent heart transplantation. The patient's own heart improved during the treatment and the native heart functioned again after the system was explanted. The main complications during treatment are bleeding, infection, thromboembolic events and systemic failure. Permanent, fully implantable mechanical circulatory pumps are under development--which may herald the beginning of a whole new era for treatment of cardiac failure.

[Economic aspects of implementation of the mechanical heart, "HeartMate"]

This economic evaluation was performed to assess the economic consequences for society and for the Danish health care sector of replacing the traditional treatment with Biomedicus assist device with The Mechanical Heart, HeartMate, as a bridge to transplantation for patients with severe cardiac failure. A cost-effectiveness analysis showed that the use of HeartMate is more cost-effective than the use of Biomedicus assist device. Using HeartMate one life-year gained costs DKK 225,000. Using Biomedicus one life-year gained costs DKK 270,000. The use of HeartMate results in an additional expenditure of DKK 615,000 per patient. By this additional expenditure the patients gain 3.6 extra life-years on average. The marginal expenditure by replacing the Biomedicus treatment with HeartMate is DKK 170,000 per extra life-year gained.

Primary closure of deep sternal wound infection following open heart surgery: a safe operation?

BACKGROUND

Deep median sternotomy wound infection is a significant source of morbidity and mortality after cardiac operations. Management of an infected median sternotomy incision is a subject of controversy. The aim of this study was to assess our experience with primary closure without any irrigation system for infected deep median sternotomy wound.

METHODS

Between January 1994 and December 1997, 4,227 consecutive open heart procedures via a median sternotomy under cardiopulmonary bypass were performed in our department. A total of 27 (0.64%) consecutive patients with deep sternotomy wound infection were identified. The mean age of the patients was 45 years. Six were female and 21 were male.

RESULTS

The incidence of deep sternal wound infection was therefore 0.64%. The mean duration between the primary operation and the onset of deep sternal wound infection was 2.5 weeks. Staphylococcus aureus and Staphylococcus epidermidis were the most common pathogen causing postoperative mediastinal infection. Out of the 27 cases, 17 were successfully treated, 8 (30%) died and 2 had a persistent fistula. The mean follow-up time was 18 months (range 4 to 52 months). The mortality in the pediatric group was 4/8 (50%) and 4/19 (21%) in the adult group. The mortality for mediastinitis presenting before one week or after 4 weeks after operation was 63%. In contrast, the mortality for mediastinitis presenting after one week but before 4 weeks after operation was 17%.

CONCLUSIONS

Mediastinitis after cardiac surgical procedures remains a devastating complication. Primary closure without irrigation-suction system should only be considered in selected patients.

Apoptosis and formation of peroxynitrite in the lungs of patients with obliterative bronchiolitis

BACKGROUND

Obliterative bronchiolitis (OB) is the principal long-term complication of lung and heart-lung transplantation. OB is characterized histologically by inflammation, epithelial cell loss, fibrosis, and obliteration of the terminal airways. The contribution of apoptosis and peroxynitrite formation in OB was examined and assessed whether immunohistochemical markers of these reactions in transbronchial biopsy specimens were predictive of OB development.

METHODS

Pulmonary tissue samples from lung transplant recipients with OB (n = 5) or without OB (control group; n = 7) were investigated by in situ terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) and nitrotyrosine immunohistochemistry. Furthermore, TUNEL and nitrotyrosine expression was compared between matched transbronchial biopsy specimens from the two patient groups.

RESULTS

Sections with active OB displayed a significantly increased number of TUNEL-positive epithelial cells and macrophages compared with very little TUNEL in control specimens. TUNEL was almost absent in inactive OB. Nitrotyrosine was detected in all samples of pulmonary tissue, but nitrotyrosine expression was more intense in patients with active OB. There was no apparent temporospatial correlation of TUNEL and nitrotyrosine expression, and in matched transbronchial specimens, these immunohistochemical markers failed to identify patients with imminent risk of developing OB.

CONCLUSIONS

Apoptosis contributes to the pathophysiology of active OB but is apparently not directly paralleled by tissue peroxynitrite formation. In transbronchial biopsy specimens, markers of apoptosis and peroxynitrite formation are not valid predictors of OB and more studies are required to deliniate the role of these mechanisms in pulmonary allograft rejection.

The porcine bronchial artery. Anastomoses with oesophageal, coronary and intercostal arteries

Information about the existence and anatomy of arterial anastomoses with the porcine bronchial artery is lacking in the literature. Prior to basic physiological investigations in a porcine model related to lung transplantation with bronchial artery revascularisation, this study was designed to examine the anatomy of systemic arterial anastomoses with the bronchial artery system. Twenty pigs were studied in 3 groups. In 2 groups the heart-lung block was removed with all mediastinal structures. One group served for investigation of coronary-bronchial artery anastomoses and one for investigation of oesophageal-bronchial artery anastomoses. The systemic arteries to be examined were cannulated. The inflated heart-lung block was examined macroscopically with Evans blue, and radiographically after contrast injection. In the 3rd group intercostobronchial artery anastomoses were studied radiographically with the heart-lung block in situ. Coronary-bronchial artery anastomoses were demonstrated in 3 of the 5 pigs with an aortic 'pouch' technique, but contrast was very limited in 2 of these 3. Oesophageal arterial anastomoses with bronchial arterial branches and/or the pulmonary veins were demonstrated in 6 of the 7 pigs and more markedly than the coronary-bronchial anastomoses. Intercostobronchial artery anastomoses could not be demonstrated angiographically. It was concluded that the existence of coronary-bronchial and oesophageal-bronchial artery anastomoses in the pig appear to establish an arterial net between the base of the heart and the distal oesophagus. The resemblance to human oesophageal-bronchial artery anastomoses supports use of a porcine model for experimental studies.

Apoptosis in acute pulmonary allograft rejection and cytomegalovirus infection

Apoptosis is a form of programmed cell death, characterized by activation of endonucleases that cleave DNA into oligonucleosomal fragments, which can be identified by in situ terminal deoxyribonucleotide transferase-mediated dUTP nick-end labeling (TUNEL). This process has recently been implicated in cardiac and hepatic allograft rejection, and we investigated its contribution to acute pulmonary allograft rejection and cytomegalovirus (CMV) pneumonitis by in situ TUNEL of transbronchial biopsy specimens. In situ TUNEL was performed on 70 transbronchial biopsy samples collected from 25 pulmonary allograft recipients for diagnosis of acute rejection or CMV pneumonitis, and the number of apoptotic nuclei/mm2 was correlated with the rejection grade (International Society of Heart and Lung Transplantation classification). During acute pulmonary allograft rejection, apoptotic nuclei were demonstrated in pulmonary parenchymal cells and mononuclear infiltrating cells, and the number of apoptotic cells was positively correlated with the rejection grade. In addition, a marked increase in the density of apoptotic cells was found in pulmonary allografts with CMV pneumonitis. We conclude that apoptosis contributes to cell death during acute pulmonary allograft rejection and CMV infection.

[Lung volume reduction surgery. A new surgical therapeutic possibility for patients with emphysema]

Lung volume reduction surgery is a new surgical procedure for treatment of patients with pulmonary emphysema. At the operation the most peripheral parts of the lung are resected. Only 15-20% of the patients admitted for lung volume reduction surgery are suitable for operation. The preliminary results have demonstrated improvement in lung function in the majority of the patients. Most of the reports comprise small numbers of patients and have a short time of observation. The longest reported period of observation for a larger number of patients is 24 months and shows a continuing improvement in lung function, dyspnoea and six minute walk test. Because of the high incidence of emphysema, lung volume reduction is a procedure that could reach large extension in the future. However, better definition of criteria of inclusion and better evaluation of the operative procedures are needed.

[Primary pulmonary hypertension]

Primary pulmonary hypertension (PPH) is defined as continuing increase of the blood pressure in the pulmonary arteries without any known reason. The expected incidence in Western Europe is one to two per one million inhabitants, which in Denmark is around five to ten new cases each year. The diagnosis PPH is established by excluding other known reasons for secondary pulmonary hypertension. Primary pulmonary hypertension is a progressive and incurable disease. The treatment of PPH is with vasodilatory agents and anti-coagulants with supplementary diuretics, digoxin and oxygen as second-line of treatment. The most important vasodilators are calcium-antagonist and Epoprostenol (prostacyclin PGI2). Lung transplantation or combined heart and lung transplantation is at the moment the only possible treatment for progressive PPH disease in Denmark. The one year survival after lung- or heart and lung transplantation for PPH are not as good as the survival among other patients who are heart and lung transplanted.

The porcine bronchial artery: surgical and angiographic anatomy

The pig is often used in experimental studies on the significance of bronchial artery circulation, but the anatomy of this artery is only poorly described. The purpose of this study was to improve the anatomical basis for experimental studies on the porcine bronchial artery circulation. The origin of the artery from the aorta is described in 32 pigs. Heart-lung blocks were perfused with saline and removed in 16 pigs, and the broncho-oesophageal orifice was identified and cannulated. In these 16 specimens the intrapulmonary ramification was studied by angiography, and the extrapulmonary distribution and supply area by injection of Evans Blue. The broncho-oesophageal artery originated from the aorta as a single trunk in 91%. Angiography showed that each principal bronchus was accompanied by 2 bronchial artery branches far into the lung parenchyma. The central branching pattern of the artery between the aorta and the principal bronchi was divided into 3 subtypes. Evans Blue showed communication with the whole mediastinum. The anatomical relations are described. It is concluded that the broncho-oesophageal artery divides to follow each bronchus with 2 bronchial branches. A nomenclature for these branches is suggested. The pig anatomy is suited for experimental investigations on the bronchial circulation.

A rat model with an isolated bladder in situ

This paper describes our method for producing a rat model with an isolated bladder in situ in which the bladder makes no contact with urine. First, the right kidney was removed, then an external catheter was placed in the right ureter for bladder infusions, and next the left ureter was anatomosed to the proximal part of the descending colon. The animals were treated with antibiotics, and saline was infused daily into the bladder in order to prevent atrophy. This in situ model is considered to be useful in studies investigating the influence of specific compounds, such as carcinogens, on the bladder and its urothelium.

[Clinical results after en block double lung transplantation with direct bronchial revascularization. The first three and a half years' experience in Denmark]

En-bloc double lung transplantation with tracheal anastomosis and direct revascularization of the bronchial arteries to the left internal mammary artery has been carried out in Denmark since June 1992. Forty-seven patients (32 with alfa-1 antitrypsin deficiency, 11 with chronic obstructive pulmonary disease, two with cystic fibrosis and two with primary pulmonary hypertension), 25 men and 22 women, average age 39 years (17-64 years), have received their first double-lung transplant with bronchial artery revascularization. Arteriography of the internal mammary artery and bronchial arteries was performed in 42 (89%) of the patients from 1-150 days after the operation. Successful bronchial artery revascularization was demonstrated arteriographically in 40 patients, in two patients the arteriography failed to show bronchial artery revascularization. Arteriography was not performed in five patients due to early complications and death. Bronchoscopy showed rapid, uncomplicated airway healing in 42 patients. Mucosal necrosis under the tracheal anastomosis was found in three patients, and severe obstructive endobronchial growth of the fungus Aspergillus fumigatus was diagnosed in the last two patients. The one- and two-year survival is 83% (Kaplan-Meier). Eleven patients are dead, five due to pulmonary causes and six due to extra-pulmonary causes. Pulmonary function became normal in nearly all surviving patients between three to six months after the transplantation. In conclusion, en-bloc double-lung transplantation with bronchial artery vascularization has shown good short-term results, and the one- and two-year survival gives hope that a successful bronchial artery revascularization will improve the long-term survival following lung transplantation.

Re-mediastinoscopy in the assessment of resectability of lung cancer

OBJECTIVE

Thirty-one patients underwent re-mediastinoscopy in the diagnostic assessment of lung cancer. The reason for a repeat mediastinoscopy was either a negative result at the first operation in spite of CT indication of enlarged nodes or an incomplete first mediastinoscopy.

METHODS

All patients underwent a conventional mediastinoscopy.

RESULTS

In 22 patients with enlarged mediastinal lymph nodes at computed tomography, 10 had a positive lymph node histology at re-mediastinoscopy, while 12 were negative. In 9 patients with no enlarged mediastinal nodes at CT scan, but incomplete biopsies at the first mediastinoscopy, 1 patient had lymph node metastases. The median duration from the first to the second mediastinoscopy was 43 days. No major complications occurred. The staging of the patients was greatly affected by the re-mediastinoscopy. Of 31 patients judged as operable according to the initial mediastinoscopy only 60% were found to be operable following the second mediastinoscopy.

CONCLUSION

This study has demonstrated the value of re-mediastinoscopy in assessment of resectability of lung cancer.

Surgical and arteriographic results of bronchial artery revascularization in lung and heart lung transplantation

BACKGROUND

On the basis of our experience with bronchial artery revascularization (BAR) in lung transplantation since its introduction in Copenhagen in 1992, a description of the surgical anatomy of the bronchial arteries and the results of attempted BAR in these patients will be presented.

METHODS

Since June 1992, BAR was performed in 50 en bloc double lung, six single lung, and nine heart-lung transplantations. The location, number, type, and size of each bronchial artery identified and revascularized were recorded. Our choice of conduit for BAR was the internal mammary artery. Routine internal mammary-bronchial arteriography was performed early after the transplantation to evaluate the result of BAR. All arteriograms were carefully studied together with the surgical records. The arteriographic results after attempted BAR were classified as complete, incomplete (bilateral, hemilateral, or poor), or failed. The surgical and arteriographic anatomy of the bronchial arteries has been described, and nomenclature for the as yet unnamed bronchial arteries has been developed.

RESULTS

During surgery 128 bronchial arteries were identified in the descending aorta of the 64 donor lung blocs. Internal mammary-bronchial arteriography was performed in 53 patients. BAR was complete in 32, incomplete in 18, and failed in 3. The number of bronchial arteries identified and revascularized in each case increased with experience. The central and intrapulmonary bronchial artery anatomy was described, and different patterns have been identified.

CONCLUSIONS

Bronchial artery identification is reliable, but a learning process is involved. BAR is possible with a high success rate. Complete BAR is an obtainable goal in most cases.

[Coronary bypass surgery at the Rigshospitalet 1993-1995. Results after 1.000 consecutive operations]

During 1993-95 1000 consecutive patients were admitted for coronary bypass surgery. The total 30-day mortality of 1.9% was 0.9% for elective cases, 0.8% for reoperations and 0.2% for urgent cases. Perioperative myocardial infarction occurred in 44 patients of whom 25% had infarction at the start of the operation. Respiratory insufficiency occurred in 1.4% of the patients, 3.6% developed renal insufficiency and 1.8% had neurological defects postoperatively. Reoperation for bleeding occurred in 6%, and 0.2% developed sternal or mediastinal infection. This study demonstrates that the results of coronary bypass surgery at Rigshospitalet, Copenhagen are fully comparable to similar results in our neighbouring countries. The results can probably be further improved by more intensive treatment of perioperative ischaemia, especially in reoperations and urgent cases.

Revascularization of the bronchial arteries in lung transplantation: an overview

Development of the surgical technique has minimized the incidence of airway problems associated with single as well as sequential bilateral lung transplantation. Although early results are good, long-term results remain unsatisfactory. The main problems after lung transplantation are pulmonary infections and the bronchiolitis obliterans syndrome. The bronchiolitis obliterans syndrome is usually considered to be chronic rejection, but a multifactorial genesis including airway ischemia has been suggested. We reviewed the literature relevant to direct bronchial artery revascularization during lung transplantation. Although information is limited, there are good reasons to believe that reestablishment of the dual blood supply to the transplanted lung is beneficial not only for healing of the airway anastomoses, but also for the airway and the lung responses to pathologic conditions. In small series, methods of bronchial artery revascularization have proved successful and have been associated with good early results. We believe it is justified to test the impact of direct bronchial artery revascularization on outcome after lung transplantation in large clinical series.

Unoperated aortic aneurysm: a survey of 170 patients

From 1984 to 1993, 1,053 patients were admitted with aortic aneurysm (AA) and 170 (15%) were not operated on. The most frequent reason for nonoperative management was presumed technical inoperability. Survivals for patients with thoracic, thoracoabdominal, and abdominal AA were comparable. No significant differences in survival for patients with dissecting and nondissecting AA were detected. In all, 132 patients (78%) died and 78 (59%) of them died of rupture. Mean time to rupture was 1,300 +/- 8 days. Cumulative 5-year hazard of rupture for the dissecting AA was twice that of the nondissecting (p < 0.001). Hazards of rupture for type A and B dissections were comparable. Diameter of 6 cm or greater was associated with a fivefold increase in cumulative hazard of rupture (p < 0.001). Diameter of AA, incidence of renal failure, and arterial hypertension were predictive of mortality, whereas the first two variables were predictive of rupture. In conclusion, because the majority of patients in all subgroups died of rupture, all patients should be recognized as candidates for surgical treatment. Present data justify aggressive approach to the patient with AA 6 cm or more in diameter and type A dissections. The results suggest that type B dissections may have a more favorable course if operated on, but a prospective, randomized study is necessary to confirm this observation. We believe that older patients and those with a small aneurysm may benefit from early, elective operation.

Aspects of integration in HIS

One of the most important characteristics of a hospital information system (HIS) is integration. It can be divided into five types, i.e. integration regarding technical infrastructure, user interface, data, semantic content, and functionality. These types of integration, their advantages, disadvantages and necessary conditions, are described in relation to the concept of an 'open' HIS and the ongoing standardization process.

Effect of secretin and somatostatin on secretion of epidermal growth factor from Brunner's glands in the rat

The effect of secretin and somatostatin on secretion of epidermal growth factor (EGF) from Brunner's glands was investigated in rats. Secretin increased volume secretion and the median output of EGF rose from 720 fmol/5 hr (total range 460-1320) in controls to 2065 fmol/5 hr (total range 1560-2730) at a dose of 50 pmol/kg/hr of secretin. Somatostatin inhibited Brunner's gland secretion, but the total output of EGF remained unchanged. Secretin-stimulated volume secretion and secretion of EGF was significantly reduced by simultaneous infusion of somatostatin. This study has shown that secretin stimulates secretion of EGF as well as volume secretion from Brunner's glands. Somatostatin prevents the effect of secretin on Brunner's glands, which suggests a role for somatostatin in control of Brunner's gland secretion.

Abdominal aortic aneurysm surgery: survival and quality of life in patients requiring prolonged postoperative intensive therapy

The goal of this study was to identify patients who need longer care in the ICU (more than 48 hours) following abdominal aortic aneurysm (AAA) surgery and to evaluate the influence of perioperative complications on short- and long-term survival and quality of life. AAA surgery was performed in 553 patients, 51 (9%) of whom died within the first 48 hours. Of the 502 patients who survived for more than 48 hours, 109 required ICU therapy for more than 48 hours, whereas 393 patients were in the ICU for less than 48 hours. The incidence of preoperative risk factors was similar for the two groups. The cumulated survival rates for the two groups were 68% and 92% at 1 months, 52% and 88% at 1 year, and 60% and 33% at 6 years, respectively. This significant difference was primarily related to renal, pulmonary, and cardiac complications. However, assessment of the most severe complications and risk factors combined failed to permit identification of patients in whom the perioperative survival rate was 0%. Even 20% of patients with multiorgan failure survived for 6 months. Of those patients who needed ICU therapy for more than 48 hours, 41 (38%) were alive at the end of 1988. In response to a questionnaire, 78% stated that their quality of life had improved or was unchanged after surgery and had resumed working. These data justify a therapeutically aggressive approach, including ICU therapy following AAA surgery, despite failure of one or more organ systems.

[Tetracycline pleurodesis in the treatment of spontaneous pneumothorax]

From 1979 to 1988 483 patients were admitted with primary spontaneous pneumothorax. All patients underwent thoracoscopy to identify the cause of pneumothorax. Chemical pleurodesis with tetracycline was performed if cysts less than 2 cm in diameter were found. If larger cysts were found the patient underwent thoractomy. In 93 patients with cysts larger than 2 cm the recurrence rate after thoracotomy was 4%. In 390 patients treated with intrapleural instillation of tetracycline, the recurrence rate was 16% (61 patients). The cause of recurrence in 42 patients was cysts missed at the initial thoracoscopy. This study has demonstrated that thoracoscopy is a reliable and safe method for selection of patients for chemical pleurodesis.

Coronary artery bypass surgery in patients with severe left-ventricular dysfunction

In the period 1988-91 31 patients with depressed function of the left ventricle but without valvular disease or congestive heart failure underwent coronary arterial bypass surgery. The median number of previous infarctions was 1.7 (0-4). Four patients had no history of previous myocardial infarction. All patients had ischemic heart disease and significant stenoses of the circumflex artery, the left anterior descendent artery, or the right coronary artery. Preoperatively the mean left-ventricular ejection fraction (LVEF) was 20% (9-26) judged by echocardiography. The median number of peripheral anastomoses was 4.9 (2-7). The perioperative mortality was 9.7%. One year survival was 90%. Postoperatively the median LVEF increased to 35% (11-50). After surgery the working capacity increased in 71% of the patients. This study has demonstrated that coronary arterial bypass surgery in patients with ischemic heart disease and poor left-ventricular function caused mainly by perfusion defects may result in symptomatic and functional benefit.

Natural history of abdominal aortic aneurysm: a survey of 63 patients treated nonoperatively

During a 10-year period in which 735 patients presented with abdominal aortic aneurysms to our clinic, 63 were not offered operative treatment. The primary reason for choosing conservative treatment was concomitant diseases that increased the risk of operation. After 2 years of followup, half of the patients died, and the cumulative 5-year survival rate was 15%. Aneurysm rupture was the primary cause of death. The cumulative 5-year mortality hazard rate from rupture was 0.36, corresponding to an annual risk of rupture of 7%. The cumulative 5-year hazard rate of death from all other causes was 1.53, corresponding to an annual risk of 30%. Diameter of the aneurysm was found to be the only factor with a significant impact on the rate of rupture. The cumulative 5-year hazard rate of rupture among patients with aneurysms < 6 cm and > or = 6 cm was 0.2 and 0.6, respectively, corresponding to an annual risk of rupture of less than 5% and 10% to 15%, respectively. However, neither diameter nor other risk factors had significant influence on the time of rupture. In our opinion, once the diagnosis is confirmed the patient should be offered aneurysm resection if the general health status permits anesthesia.

Intra-aortic balloon counterpulsation in Denmark 1988-1991. Early results and complications

During the years 1988-1991 6319 patients underwent cardiac surgical procedures in Denmark. In 183 patients (2.9%) with left ventricular failure intra-aortic balloon counterpulsation (IABP) was used. Four percent of the IABP were placed preoperatively, 86% intraoperatively and 10% postoperatively. Severe complications occurred in 16 patients (8.7%) and were mainly vascular due to limb ischemia. The incidence of complications was independent of the duration of balloon pumping. Sixty percent of the patients were weaned from IABP. The 30-day mortality rate was 54%. During the observation period we found a gradual decrease in the use of IABP as well as a reduction in mortality.

Long-term results after tetracycline pleurodesis in spontaneous pneumothorax

From 1979 to 1988 483 patients were admitted with primary spontaneous pneumothorax. All patients underwent thoracoscopy to identify the cause of pneumothorax. Chemical pleurodesis with instillation of tetracycline was performed if cysts less than 2 cm in diameter were found. If larger cysts were identified the patient underwent thoracotomy. In 93 patients with cysts larger than 2 cm the recurrence rate after thoracotomy was 4%. In 390 patients treated with intrapleural instillation of tetracycline, the recurrence rate was 16%. Fifty percent of the recurrences occurred within 30 days. The cause of recurrence in 42 patients (69%) was cysts missed at the initial thoracoscopy. This study has demonstrated that thoracoscopy is a reliable and safe method for selection of patients for chemical pleurodesis. It is, however, necessary that the thoracoscopy is meticulous to avoid recurrence from missed cysts.

Stimulatory effect of epidermal growth factor on liver regeneration after partial hepatectomy in rats

The effect of epidermal growth factor (EGF) on liver regeneration was investigated in rats subjected to partial hepatectomy. In a dose-response study EGF in doses of 6 and 24 nmol/kg x day increased liver regeneration after treatment for 48 h compared with controls, whereas a dose of 48 nmol/kg x day had no effect. In a subsequent study EGF, 6 nmol/kg x day, accelerated liver regeneration significantly after 36, 48, and 72 h of treatment. A possible influence of EGF on other hepatotrophic factors was investigated. No changes in the concentration of gastrin, insulin, or glucagon was found in portal venous blood. This study has shown that EGF in small doses can stimulate liver regeneration, whereas higher doses are ineffective. The study suggests that EGF should be regarded as a hepatotrophic factor.

[Coronary bypass surgery in patients with decreased function of the left ventricle]

During 1988-1990, 21 patients with poor left ventricular function underwent coronary artery bypass surgery. The median number of previous infarctions was 1.6 (0-4). Three patients had no previous history of myocardial infarction. All patients had ischemic heart disease and significant stenoses or occlusion of the circumflex artery, the left anterior descendent artery and the right coronary artery. Preoperatively the left ventricular ejection fraction (LVEF) was 23% (10-28) judged by echocardiography. The median number of peripheral anastomoses was 4.8 (2-7). The perioperative mortality was 9.5%. One year survival was 90%. Postoperatively the median LVEF increased to 35% (25-50). The working capacity increased in 70% of the patients. This study has shown that coronary arterial bypass surgery in patients with ischemic heart disease and poor left ventricular function may result in symptomatic and functional benefit.

Surgery for abdominal aortic aneurysms. A survey of 656 patients

Between 1979 and 1988, 656 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed in 287 patients (44%) and acute operation in 369 patients. A ruptured aneurysm was found in 218 patients (33%). Patients with arteriosclerotic heart disease, hypertension, impaired renal function or chronic pulmonary disease showed an increased perioperative mortality. Development of postoperative cardiac and renal complications could not be related to previous cardiac or renal diseases. The major postoperative complications were renal failure in 81 patients (12%), pulmonary insufficiency in 77 patients (11%) and cardiac complications in 96 patients (13%). Failure of one or more organs occurred in 153 patients (23%) and the mortality rate for patients with multiorgan failure was 68%. Complications leading to reoperation occurred in 93 patients (14%). The perioperative mortality was 18.8%. The mortality for elective cases was 4.8%, for symptomatic cases 17.2% and 37% for ruptured aneurysms. The five-year survival rate was 48% for ruptured aneurysms, 70% for symptomatic cases and 75% for elective cases. After six months the life expectancy in these three groups of patients were identical and comparable to the expected survival for a sex and age matched control population.

[Mortality and survival after surgery for abdominal aortic aneurysm. A 10-year follow-up]

From 1979-1988, 656 patients were operated for abdominal aortic aneurysm. The perioperative mortality was 18%. The mortalities for elective, symptomatic and ruptured aneurysms were 5%, 17% and 38% respectively. The overall five year survival rate was 58%. In 87% of the patients one or more risk factor was found. Survival was unaffected in patients with a single risk factor, whereas patients with two or more risk factors had lower five year survival. Postoperative organ failure increased the perioperative mortality and the five year survival in patients with multiorgan failure was 20%. In view of the fact that 56% of the patients are operated on as emergencies, this study stresses the importance of early diagnosis and elective treatment.

Surgical treatment of large pericardial effusions. Etiology and long-term survival

From 1977 to 1988 60 patients were treated for large pericardial effusion. The operation consisted of a small left anterior thoracotomy with formation of a pericardial window. In 28 patients (47%) the etiology was a malignant disease. Eight patients (29%) had malignant cells in the pericardial fluid and 23 patients (82%) had metastases to the pericardium. Seven patients (12%) had purulent pericarditis; in 4 cases Staphylococcus was found. Of the remaining 25 patients, the etiology remained unknown in 13. The 5-year survival rate was 60% among patients with nonmalignant effusions. In patients with malignant effusions only 20% were alive after 2 years. There were no deaths related to the operation. We conclude that large pericardial effusions of unknown etiology can be safely treated with a small left anterior thoracotomy. This access gives optimal possibilities for rapid diagnosis and treatment.

Renal failure after operation for abdominal aortic aneurysm

Among 656 patients undergoing surgery for abdominal aortic aneurysm, 81 patients (12%) developed postoperative renal failure. Before operation hypotension and shock occurred in 88% of the patients with ruptured aneurysm, whereas none of the patients operated electively were hypotensive. Dialysis was performed in 32 patients, while the remaining 49 patients were managed without dialysis. Within 30 days after the operation 47 patients (58%) had died. There was no difference in mortality between patients in dialysis and patients managed without dialysis. Thirteen patients died during follow-up. In six cases the death was caused by renal failure only or in combination with failure of other organs. Analysis of the cumulative survival shows that, if the patients survive the postoperative period, their life expectancy is comparable to that of patients without renal complications.

Does survival depend on the amount of autotransplanted splenic tissue?

Susceptibility to Streptococcus pneumoniae infection was studied in 11 groups of rats allocated to sham operation, splenectomy, or splenic autotransplantation of 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, or 90% of the removed spleen. Three months later, all rats were exposed intravenously to type 1 Streptococcus pneumoniae (median lethal dose, LD50, for control group). Survivors were killed 13 days after the bacterial challenge. Autopsy showed that more splenic tissue was recovered in rats that received less than 50% splenic tissue compared with those that received 50% or more. More survivors were found among sham-operated rats (47.5%; 95% confidence intervals, 32 to 68) and rats that had 40% splenic tissue implanted (35%; confidence interval, 20 to 54) or those that were found to have regenerated 40% splenic tissue. We conclude that 40% of the spleen should be autotransplanted to protect the rat optimally against infection after splenectomy.

The first year with a J-pouch. A prospective evaluation

Proctocolectomy and construction of a pelvic pouch with ileo-anal anastomosis is now an established method in the treatment of ulcerative colitis, but various procedures are still under evaluation. This series comprises 97 patients with a 20 cm long J-shaped pouch and a short rectal cuff of 2-5 cm, prospectively evaluated after 1, 3, 6 and 12 months. Eight patients had their pouch removed because of septic complications. All the remaining patients evacuate spontaneously, although around one third still use constipating agents after 1 year. The stooling frequency gradually diminished from 7 (4-15) per 24 h to 4 (2-6) after 12 months. Continence also gradually improved during this period. No patient was incontinent of faeces but 13% still experienced episodes of minor soiling after 12 months. The procedure has proved to be safe providing patients are carefully selected, and 90% achieve a satisfactory or acceptable functional result.

[Surgical treatment of abdominal aorta aneurysm 1983-1987. A multicenter study. 1266 operations, development and early results]

During the years 1983-1987, 1,266 operations for abdominal aortic aneurysm (AAA) were carried out in eight surgical departments with vascular surgical function. The activity increased constantly corresponding to 311 patients in 1987 or 50% more than in 1983. During this period the distribution between patients subjected to elective operation and those operated upon as emergencies was very uniform. In the latter group, only a slight increase in the number of AAA patients with rupture was observed. The risk of complications was low with a significant decrease in the need for dialysis. The early mortality was constant for the patients subjected to elective operation remained constant about 5.5%. A marked decrease in the early mortality was observed for the patients operated upon as emergencies with rupture from 63 to 50% and without rupture from 37 to 25%. At the conclusion of the period, ultrasonic scanning became the preoperative investigation of election and introduction of an aortic prosthesis the method of operation of election. Patients with AAA should be recognized so that elective surgery can be offered before a condition endangering life develops.

[Early and late results after surgery of abdominal aortic aneurysm]

From 1983-1987, 388 patients were operated upon for abdominal aortic aneurysm. Elective operation was performed on 171 patients (44%) with a mortality of 2.9%. Emergency operation was done in 277 patients of whom 132 (34%) had ruptured aneurysms. The mortality for ruptured aneurysms was 36% and 21% for patients operated on as emergencies without signs of rupture of the aneurysm. The five year survival rate was 75% after elective operation, 60% after emergency operation and 40% after operation for ruptured aneurysm. The high mortality after emergency operation for abdominal aortic aneurysm confirms the importance of early diagnosis and elective operation before rupture occurs.

Effect of gastrin on liver regeneration after partial hepatectomy in rats

Gastrin has been shown to be an important trophic hormone for the mucosa of the stomach and the proximal intestine. In the present study the effect of gastrin on liver regeneration after partial hepatectomy in rats was investigated. After partial hepatectomy a significant rise in the concentration of gastrin in portal venous blood was found six, 12, and 18 hours after 70% hepatectomy. The effect of changes in the endogenous gastrin concentration on the liver regeneration was investigated in rats subjected to antrectomy or to fundectomy. Partial hepatectomy was done three weeks after the primary surgery. We found antrectomy to decrease liver regeneration, whereas fundectomy had no effect. Administration of pentagastrin 300 micrograms/kg sc three times daily for two and four days after partial hepatectomy significantly increased the rate of liver regeneration compared with controls. This study suggests that gastrin has a hepatotrophic effect. Whether this effect is caused by a direct action of gastrin on the hepatocytes or it is an indirect effect mediated by for instance insulin, glucagon or epidermal growth factor has to be further investigated.

Pharmacokinetics and metabolism of neurotensin in man

We studied the pharmacokinetics, arteriovenous extraction, and degradation sites of neurotensin (NT) in man during iv infusions of synthetic intact NT [NT-(1-13)] and the NH2-terminal metabolite NT-(1-8) during lipid ingestion and by catheterization of various vascular beds in normal subjects and patients with hepatic disease. NT-like immunoreactivities in plasma were quantitated using 2 sequence-specific RIAs and gel filtration chromatography. During iv infusion of NT-(1-13) in 6 normal subjects, the median t1/2 was 1.7 min (interquartile range, 0.7-2.8), the MCR was 36 mL/kg.min (range, 21-54), and distribution space was 78.8 mL/kg (range, 56-91). The results were similar at infusion rates of 72, 144, and 288 pmol/kg.h (n = 6). During infusion of NT-(1-8) in 7 normal subjects, the median t1/2 was 8.3 min (range, 4.7-13.8), the MCR was 11.0 mL/kg.min (range, 6.7-21.7), and the distribution space was 142.6 mL/kg (range, 45.3-281.0). Significant peripheral arteriovenous extraction of NT-(1-13) was found at infusion rates of 144 and 288 pmol/kg.h. Extraction of NH2-terminal immunoreactivity was not significant. Intact NT was identified by gel chromatography in arterial plasma after lipid ingestion and iv infusion of NT-(1-13), but postprandially in only low concentrations. In 17 patients with various nonhepatic diseases, plasma intact NT levels were not different in blood sampled from the renal vein, inferior vena cava, brachial artery, or hepatic vein. In contrast, NH2-terminal immunoreactivity was significantly higher in hepatic venous than in systemic plasma. In 6 patients with hepatic disease, systemic plasma intact NT levels were increased, but even more so in hepatic venous plasma. These results demonstrate that metabolism of intact NT is rapid, and a significant peripheral arterio-venous extraction is present. Further studies are necessary to establish if the liver is a site of degradation of intact NT in man.

Intravascular air after fibrin sealing by spray gun in cardiovascular surgery

During an operation for an ascending aortic aneurysm with implantation of a saphenous vein graft to the left coronary artery into a prosthesis, we occasionally observed air bubbles in the graft after application of fibrin glue to the anastomosis to control bleeding. In an experimental study in a pig, a vascular prosthesis was anastomosed to the descending aorta. The aorta and the prosthesis were transected and reanastomosed. Air bubbles were collected in a glass flask placed at the end of the prosthesis. Fibrin glue was applied with a spray catheter on all anastomoses at varying distances and with different air pressures. Small amounts of air were collected in the glass flask when an air pressure of 3 or 4 bar was used. This study demonstrates that the use of fibrin glue in cardiovascular surgery can introduce air into the vascular system with subsequent air emboli as a possible side-effect.

Long-term results after arterial surgery for arteriosclerosis of the lower limbs in young adults

Ninety-nine patients, with a mean age of 40 years, underwent surgery for arteriosclerosis of the lower limbs during 1975-81. The main indication for surgery was claudication and the median observation time 102 months (range 54-138 months). Twenty patients died during the follow-up period and fifteen of these could be related to arteriosclerotic disease. At follow-up, 43 patients had claudication, while 34 patients had developed other arteriosclerotic manifestations. Amputation was performed in 17 patients. At follow-up the number of patients at work remained almost unchanged, whereas the number of patients receiving disablement pension increased. This study shows that younger patients with arteriosclerosis of the lower limbs had a mortality of approximately 20%, during the period of observation of this study. However, many patients became asymptomatic after surgery suggesting that a conservative attitude to arterial surgery in these patients cannot be justified.

Neurotensin-like immunoreactivity after intestinal resection in the rat

Neurotensin is a tridecapeptide located mainly in the distal small intestine. The present study was carried out in order to investigate the neurotensin response after proximal small intestinal resection in the rat. After resection, the median plasma concentration of neurotensin like immunoreactivity (NTLI) was unchanged compared with sham operated rats. Intragastric instillation of fat increased the plasma concentration of NTLI from 45 pmol/l (34-63) in sham operated rats to 92 pmol/l (46-121) in resected rats. No significant increase in the plasma concentration of NTLI was found after intragastric instillation of amino acids or glucose. The tissue concentration of NTLI increased significantly in the jejunum and ileum after proximal small intestinal resection, while the number of immunoreactive neurotensin cells was unchanged. This study shows that the adaptive responses in the distal small intestine after proximal small intestinal resection also involve the neurotensin producing cells.

Secretion of goblet cell serine proteinase, ingobsin, is stimulated by vasoactive intestinal polypeptide and acetylcholine

Ingobsin is localized to the intestinal goblet cells in the rat and in man. In the present study, we investigated the effect of vasoactive intestinal polypeptide (VIP) and acetylcholine on the secretion of ingobsin from the proximal duodenum. Intravenous infusion of VIP or acetylcholine increased the concentration of ingobsin in duodenal secretion, while the concentration in the duodenum was unchanged. Simultaneous infusion of VIP and acetylcholine increased the concentration of ingobsin in duodenal secretion and decreased the concentration of ingobsin in the duodenum. This study demonstrates that secretion of ingobsin from the proximal duodenum is exocrine and can be stimulated by VIP and acetylcholine.