Torsten Bossert

A comparative study of four intensive care outcome prediction models in cardiac surgery patients

BackgroundOutcome prediction scoring systems are increasingly used in intensive care medicine, but most were not developed for use in cardiac surgery patients. We compared the performance of four intensive care outcome prediction scoring systems (Acute Physiology and Chronic Health Evaluation II [APACHE II], Simplified Acute Physiology Score II [SAPS II], Sequential Organ Failure Assessment [SOFA], and Cardiac Surgery Score [CASUS]) in patients after open heart surgery.MethodsWe prospectively included all consecutive adult patients who underwent open heart surgery and were admitted to the intensive care unit (ICU) between January 1st 2007 and December 31st 2008. Scores were calculated daily from ICU admission until discharge. The outcome measure was ICU mortality. The performance of the four scores was assessed by calibration and discrimination statistics. Derived variables (Mean- and Max- scores) were also evaluated.ResultsDuring the study period, 2801 patients (29.6% female) were included. Mean age was 66.9 ± 10.7 years and the ICU mortality rate was 5.2%. Calibration tests for SOFA and CASUS were reliable throughout (p-value not < 0.05), but there were significant differences between predicted and observed outcome for SAPS II (days 1, 2, 3 and 5) and APACHE II (days 2 and 3). CASUS, and its mean- and maximum-derivatives, discriminated better between survivors and non-survivors than the other scores throughout the study (area under curve ≥ 0.90). In order of best discrimination, CASUS was followed by SOFA, then SAPS II, and finally APACHE II. SAPS II and APACHE II derivatives had discrimination results that were superior to those of the SOFA derivatives.ConclusionsCASUS and SOFA are reliable ICU mortality risk stratification models for cardiac surgery patients. SAPS II and APACHE II did not perform well in terms of calibration and discrimination statistics.

Prediction of mortality in intensive care unit cardiac surgical patients

OBJECTIVES The purpose of this study was to develop a specific postoperative score in intensive care unit (ICU) cardiac surgical patients for the assessment of organ dysfunction and survival. To prove the reliability of the new scoring system, we compared its performance to existing ICU scores. METHODS This prospective study consisted of all consecutive adult patients admitted after cardiac surgery to our ICU over a period of 5.5 years. Variables were evaluated using the patients of the first year who stayed in ICU for at least 24h. The reproducibility was then tested in two validation sets using all patients. Performance was assessed with the Hosmer-Lemeshow (HL) goodness-of-fit test and receiver operating characteristic (ROC) curves and compared with the Acute Physiology and Chronic Health Evaluation (APACHE II) and Multiple Organ Dysfunction Score (MODS). The outcome measure was defined as 30-day mortality. RESULTS A total of 6007 patients were admitted to the ICU after cardiac surgery. Mean HL values for the new score were 5.8 (APACHE II, 11.3; MODS, 9.7) for the construction set, 7.2 (APACHE II, 8.0; MODS, 4.5) for the validation set I and 4.9 for the validation set II. The mean area under the ROC curve was 0.91 (APACHE II, 0.86; MODS, 0.84) for the new score in the construction set, 0.88 (APACHE II, 0.84; MODS, 0.84) in the validation set I and 0.92 in the validation set II. CONCLUSIONS Most of general ICU scoring systems use extensive data collection and focus on the first day of ICU stay. Despite this fact, general scores do not perform well in the prediction of outcome in cardiac surgical patients. Our new 10-variable risk index performs very well, with calibration and discrimination very high, better than general severity systems, and it is an appropriate tool for daily risk stratification in ICU cardiac surgery patients. Thus, it may serve as an expert system for diagnosing organ failure and predicting mortality in ICU cardiac surgical patients.

Quality of Life after Mechanical vs. Biological Aortic Valve Replacement

To assess the quality of life after biological and mechanical aortic valve replacement, data of 136 patients were assessed retrospectively after 2 years of follow-up. Bioprostheses were implanted in 53 patients with a mean age of 74 years, and mechanical prostheses were used in 83 with a mean age of 64 years; there were 47 women and 89 men. Quality of life was evaluated using the Short Form 36-Item Health Survey questionnaire. Physical function scores were significantly better in patients with a mechanical prosthesis. Mental health indices were identical in both groups. Younger patients with mechanical valves and older patients with biological valves had significantly better item scores. In all age groups, men tended to have better scores than women, but a significant difference was noted only in the physical functioning index. The quality of life in patients with mechanical and biological valves was similar at 2 years postoperatively.

Implantation of the Liver During Reperfusion of the Heart in Combined Heart-Liver Transplantation: Own Experience and Review of the Literature

BACKGROUND There are only a few reports about combined heart-liver transplantations. The surgical techniques differ widely, ranging from sequential implantation of the organs to simultaneous transplantations. We report our experience with simultaneous, combined heart-liver transplantations without using a veno-venous bypass demonstrating that this is a feasible surgical technique. METHODS Since 2005, we performed 4 combined heart-liver transplantations by implanting the liver during the reperfusion period of the newly implanted heart. We retrospectively reviewed patient clinical data and outcomes. RESULTS The mean operative time was 534 ± 247 minutes and the ischemia times for heart and liver were 190 ± 72 minutes (cold ischemia time for the heart), 98 ± 96 minutes (warm ischemia time for the heart), 349 ± 101 minutes (cold ischemia time for the liver), and 36.25 ± 3.5 minutes (warm ischemia time for the liver). Three patients were discharged from the hospital after an uneventful clinical course. One patient died due to multi-organ failure during the intensive care unit stay on the 23rd postoperative day. CONCLUSION We suggest that combined, simultaneous heart-liver transplantation without veno-venous bypass is a feasible surgical technique.

Gaseous emboli during off-pump surgery with T-graft technique, two different mechanisms

OBJECTIVES Gaseous embolism is a possible complication during off-pump coronary surgery with the use of a blower and can cause ischemic injuries. We describe two different possible mechanisms of carbon-dioxide embolization. METHODS Out of 2196 coronary bypass surgeries, between 1 January 2007 and 31 December 2009, there were 977 off-pump operations. Two off-pump cases (0.2%) had gaseous (carbon-dioxide) emboli that migrated against blood stream proximally through T-anastomoses and then into the native coronary vessels. These emboli caused a temporary haemodynamic deterioration in other territories. Two types of T-anastomoses were included [saphenous vein on left internal thoracic artery (LITA) or right internal thoracic artery (RITA) on LITA]. RESULTS Simple procedures and measurements were necessary but enough to regain haemodynamic stability. There was no effect on the postoperative outcome. CONCLUSION We have concluded that carbon-dioxide emboli can also cause massive but temporary haemodynamic deterioration during off-pump surgery despite higher solubility in blood. The blower should be used only when a bull-dog clamp is applied on the graft. Also, proper de-airing and flushing of grafts is very important and avoids consequences of the trapped small emboli.

Surgical treatment of multiple atherosclerotic coronary artery aneurysms in a patient presenting with acute myocardial infarction

Priv.-Doz. Dr. med. Holger H. Sigusch Klinik für Innere Medizin I Heinrich-Braun-Krankenhaus Zwickau Karl-Keil-Straße 35 08060 Zwickau, Germany Tel.: 03 75 / 51 22 19 Fax: 03 75 / 51 15 19 Sirs: Coronary artery aneurysm (CAA) is a rare disease with the incidence being 0.15 to 4.9% [15]. Common causes are Kawasaki’s disease, Marfan syndrome and manifestation of atherosclerosis [6, 13]. Further causes are congenital, mycotic, postsyphilitic, posttraumatic, in association with connective tissue disorders and some other rare etiologies [4, 17]. Right coronary artery aneurysms (RCAA) are most frequent, followed by left anterior descending (LADA) and circumflex coronary artery aneurysms (CXA) [2, 4, 7]. The incidence of multiple coronary artery aneurysms (MCAA) among patients undergoing coronary artery angiography is rarer and is not discussed often in the literature [14]. Angina pectoris and myocardial infarction (MI) are the most common symptoms. Therapy is still disputed [8, 11, 12]. We report a case of MCAA in a 40-year old male presenting with acute posterior MI and required emergency hospital admission.

Cervical esophageal perforation by transesophageal echocardiography probe detected during coronary artery bypass grafting

vessel disease planned for total arterial myocardial revascularisation using bilateral internal mammary arteries (IMAs) and the left radial artery (LRA). Transesophageal echocardiography (TEE) probe is routinely performed in all our cardiac off pump cardiac bypass (OPCAB) surgeries. It was inserted during sternotomy. The acquired images were poor in quality, although the probe was inserted without difficulties. The operation started with left IMA harvesting and simultaneously LRA harvesting. During harvesting, the surgeon palpated a structure in the anterior mediastinum, which was the TEE probe (Fig. 1). Transesophageal echocardiography probe was retracted and removed from the cervical region. In order to avoid contamination of the right pleura cavity and to shorten the operation, we discontinued right IMA harvesting and used a saphenous vein graft (SVG) instead. In OPCAB technique, the patient received three grafts: LIMA to LAD, LRA to RCX and a SVG to the RCA. After primary closing of the chest using a closeddrainage technique to treat mediastinal contamination, we operated on the esophagus perforation by primary repair (Fig. 2). The postoperative course was uneventful and the patient was discharged. One-year follow up revealed no dysphagia or angina. Cervical esophageal perforations by a TEE Probe have a reported incidence of 0.01%–0.02% and is a catastrophic and often life-threatening event with mortality rates of 10%–40%. Nevertheless, the popularity of the TEE is caused by its impact on intraoperative cardiac surgical decision making, especially in OPCAB surgery. Torsten Bossert Markus Paxian Michael Heise Khosro Hekmat Cervical esophageal perforation by transesophageal echocardiography probe detected during coronary artery bypass grafting