Accuracy of diagnostic laparoscopy for early diagnosis of abdominal complications after cardiac surgery

BACKGROUND

In the early postoperative period after major cardiac surgery using extracorporal circulation, abdominal complications can have serious consequences with a mortality rate of up to 70%. Early diagnosis and the timely institution of therapy are the most important factors to improve the outcome; however, clinical evaluation of the abdomen is difficult in these patients. Diagnostic laparoscopy is a minimally invasive procedure with low procedure-associated morbidity, even in critically ill patients. The aims of our study were to investigate the safety of laparoscopy in critically ill patients suspected to have intraabdominal pathology following cardiac surgery and to evaluate the accuracy of diagnostic laparoscopy compared to laparotomy in this setting.

METHODS

A total of 17 patients were included (13 male, four female, age 52-80 years) in the early (3-30 days) postoperative period after cardiac surgery using extracorporal circulation (10 ACVB, four valve replacement, one aorto-coronary-venous-bypass (ACVB)+ valve replacement, two cardiac transplantation). Clinical and laboratory findings included distended abdomen (17 of 17), elevated white blood cells (12 of 17), elevated C-reactive protein (CRP) (13 of 17), and elevated lactate levels (11 of 17). The decision to perform laparotomy was taken in all patients on the basis of their clinical condition. Diagnostic laparoscopy was always performed immediately before laparotomy. The laparoscopic findings were then compared to the laparotomy findings.

RESULTS

In one patient, laparoscopy showed no abnormal findings, this was confirmed on laparotomy. Five patients were found to have massive distension of the large bowel without ischemia on both laparoscopy and laparotomy. Colonic ischemia of the right hemicolon was found laparoscopically in six patients, which was confirmed in all cases by open resection and histological workup. Three patients suffered from acute cholecystitis, which was correctly diagnosed by laparoscopy in all cases. In one patient, laparoscopy revealed fibrinous peritonitis without other findings. Open exploration failed to identify the cause of the peritonitis in this patient. Laparoscopy showed no pathological findings in one patient, but laparotomy then revealed necrotizing pancreatitis confined to the lesser sac. There was one laparoscopy-associated intraoperative complication (6%) in this series.

CONCLUSIONS

Diagnostic laparoscopy is a minimally invasive procedure that can be performed at low intraoperative risk in critically ill patients and has a high sensitivity (94%) for the correct diagnosis of intraabdominal complications after major cardiac surgery. These results suggest that bedside laparoscopy should be considered for all patients with equivocal abdominal symptoms in this setting.

Pathological changes of the myocardium in patients after atrial repair for transposition of the great arteries: a possible explanation for left ventricular dysfunction after secondary arterial switch

BACKGROUND

Patients with transposition of the great arteries who underwent an atrial repair in infancy are likely to develop right ventricular dysfunction later in life. For these patients a two-stage arterial switch operation has been advocated by some groups but mortality even from the initial pulmonary banding procedure for retraining the left ventricle has been reported to be considerable. We asked whether pathological alterations of the left ventricular myocardium could explain for the failure of the left ventricle observed in patients after two-stage arterial switch operations.

METHODS

Twelve patients aged 16.9 [8-25.4] years (median [range]) with transposition of the great arteries after atrial repair in infancy were enrolled. Median follow-up interval was 15.8 [7.8-22.1] years. Measurements of right and left ventricular systolic function were performed by echocardiography. In addition all patients underwent cardiac catheterization. Endomyocardial biopsies were taken from the right and left ventricle and examined histopathologically.

RESULTS

Two out of twelve patients showed mildly reduced systolic right ventricular function. Systolic function of the left ventricle was normal in all patients on echocardiography but six out of twelve patients showed clusters of fibrous and fatty degeneration on biopsy specimens obtained from the left ventricle.

CONCLUSION

We conclude that degenerative left ventricular myocardial changes could serve as an explanation for left ventricular failing when retraining the left ventricle during two-stage arterial switch operations.

Long-term Results after Repair of Truncus Arteriosus Communis in Neonates and Infants

BACKGROUND

We reviewed our experience of truncus arteriosus communis (TAC) repair.

METHODS

Between 05/90 and 10/01, 16 patients underwent complete repair of TAC (primary repair: group I, 12 patients, secondary repair: group II, 4 patients). Age was 2.4 months [5 days-8.8 months] (median [range]) in group I, and 8.3 [5.6-13.5] years in group II. Continuity from the right ventricle to the pulmonary artery was achieved using a valved conduit. All patients had regular follow-up examinations.

RESULTS

There was one early death in each group (12.5%). Follow-up was 9 [1.2-12.7] years. Valved conduit failure occurred in 8 patients (67 %) in group I (group II, 1 patient, 33 %) requiring replacement at 2.5 [0.3-4.3] years (group II, 5.8 years). Severe neo-aortic valve regurgitation after truncal valve repair was observed in one patient, requiring valve replacement at 8.5 years in association with repeat homograft replacement (group I). Actual echocardiographic examination revealed normal ventricular function. Moderate conduit dysfunction was noted in 2 patients (group I).

CONCLUSIONS

Complete repair of truncus arteriosus communis can be performed with excellent long-term results.

[Computer-assisted reconstruction of coronary vessels]

End stage coronary artery disease with linear stenosis of the main vessels despite several coronary interventions is a current challenge for surgical treatment. As the long term results are mainly determined by the pathology of the coronary vessels a simple revascularisation with arterial or venous grafts provides no adequate solution of the problem. An exactly controlled 3D-reconstruction of the coronary vessels enabling selective thrombendarteriectomy (TEA) seems to be a new approach, that may be limited by neointimal hyperproliferation of the coronary vessels. Intraoperative brachytherapy may be a tool to inhibit this process.

[Multi-value regulatory systems for extracorporeal circulation]

Extracorporeal perfusion is the standard technique in cardiac surgery. It is controlled by perfusionists on the basis of their clinical experience and on the available data collected pre- and intra-operatively. But in spite of intensive monitoring postoperative complications occur. An appropriate control of the heart-lung machine (HLM) using an "autopilot" might improve the quality of heart-surgery and decrease postoperative complications. Hence, a mathematical model of a human circulatory system has been developed which provides much more information about haemodynamics, blood gases and acid-base status than standard monitoring. It has been implemented on a system which is capable of integrating measured data as input parameters in real-time in the simulation. Now, soft- and hardware control concepts based on the human circulatory system have to be developed which are able to control the HLM.

Perfusion-contractility matching during Fontan circulation

We investigated the relationship between coronary perfusion pressure (CPP) and myocardial contractility and the effects of an acute elevation of right atrial pressure (RAP) on this relationship in an experimental model of Fontan circulation in 6 anesthetized open-chest dogs with isolated perfused coronary arteries. The relationship between CPP and Ees could be described by biphasic J-shaped curves which were nearly identical before and under Fontan circulation. While above a "critical" CPP (72 +/- 9 mmHg vs. 81 +/- 8 mmHg, n.s.) the changes of CPP did not affect Ees, below this level the decrease of CPP resulted in a progressive decrease of Ees. Under Fontan circulation, the progressive increase of RAP did not influence Ees at CPP = 100 mmHg, led to a moderate decrease of Ees at CPP = 75 mmHg and severe decrease at CPP = 60 mmHg. Thus, both coronary arterial and venous pressure affect myocardial contractility after Fontan procedure.

Extracorporeal circulation induced microvascular perfusion injury of the small bowel

Gastrointestinal complications following cardiopulmonary bypass (CPB) are relatively uncommon, but are associated with a high mortality rate. Impairment of bowel perfusion during and following CPB may serve as a trigger for the development of multiorgan failure. The aim of our study was the development of a new animal model allowing quantitative analysis of small bowel microcirculation during and after CPB. Twelve Landrace pigs served as laboratory animals. A 15-cm loop of the terminal ileum was exteriorized for microscopic observation. In 6 animals, a normothermic, partial left heart bypass (pLHB) was established for 2 h with a flow rate of 2,000 ml/min. Arterioles, collecting venules and the capillaries of the small bowel were recorded for the analysis of the microcirculation. All parameters were recorded prior to, during pLHB and up to 2 h after weaning off the bypass. Six sham operated animals served as controls. Despite unchanged hemodynamics, pLHB leads to microvascular perfusion disturbances of the small bowel. In pLHB animals, blood cell velocity in postcapillary venules (30-70 microm) was significantly decreased during and following bypass. Capillary density was also reduced during bypass and decreased even further after pLHB to only 30% of the control values. With this new large animal model for quantitative assessment of microvascular perfusion of the small bowel during CPB, it could be clearly demonstrated that partial normothermic left heart bypass leads to a significant disturbance of the small bowel microcirculation even under stable hemodynamic conditions.

Minimal early mortality in CABG--simply a question of surgical quality?

BACKGROUND

The increasing number of risk scores and models for the evaluation of the early risk after cardiac surgery reflects the interest in 'calculating' the risk of adverse events. Different time intervals, but also different 'types' of death are generally accepted in the evaluation of early mortality. The aim of this study was to focus on the differences in the calculation of early mortality and to focus on their potentially misleading impact on risk stratification.

METHODS

We investigated 7,436 patients who underwent coronary artery bypass grafting from June 30, 1988 through June 30, 2001. A follow-up was performed 180 days after operation (98.7 % complete).

RESULTS

According to the definition of 30-day mortality to represent the total time interval between an intervention and the 30th postoperative day, the 30-day mortality was 5.92 % (n = 440 patients). Hospital mortality reflects the number of deaths from the day of intervention through the patient's individual discharge, independent of any fixed time interval. Hospital mortality was 5.86 % (n = 436 patients) in our patient group. 30-day hospital mortality requires the investigation of hospital mortality until the 30th postoperative day; in-hospital and general mortality after the 30th postoperative day remained excluded from the analysis; 30-day hospital mortality was 5.19 % (n = 386 patients). Assuming a maximum hospital stay of 5 days, hospital mortality would decrease to 2.64 % (n = 196 patients).

CONCLUSIONS

30-day mortality, hospital mortality and 30-day hospital mortality are used to determine early outcome. The present data indicate the vulnerability of non-standardized time intervals to discharge policy. However, both hospital mortality and 30-day hospital mortality are predominantly used in current risk scores and models. In view of the comparability and meaning of data, the methodology for the evaluation of early risk should be reconsidered.