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Three-dimensional (3-D) surface imaging has gained clinical acceptance, especially in the field of cranio-maxillo-facial and plastic, reconstructive, and aesthetic surgery. Six scanners based on different scanning principles (Minolta Vivid 910®, Polhemus FastSCAN™, GFM PRIMOS®, GFM TopoCAM®, Steinbichler Comet® Vario Zoom 250, 3dMD DSP 400®) were used to measure five sheep skulls of different sizes. In three areas with varying anatomical complexity (areas, 1 = high; 2 = moderate; 3 = low), 56 distances between 20 landmarks are defined on each skull. Manual measurement (MM), coordinate machine measurements (CMM) and computer tomography (CT) measurements were used to define a reference method for further precision and accuracy evaluation of different 3-D scanning systems. MM showed high correlation to CMM and CT measurements (both r = 0.987; p < 0.001) and served as the reference method. TopoCAM®, Comet® and Vivid 910® showed highest measurement precision over all areas of complexity; Vivid 910®, the Comet® and the DSP 400® demonstrated highest accuracy over all areas with Vivid 910® being most accurate in areas 1 and 3, and the DSP 400® most accurate in area 2. In accordance to the measured distance length, most 3-D devices present higher measurement precision and accuracy for large distances and lower degrees of precision and accuracy for short distances. In general, higher degrees of complexity are associated with lower 3-D assessment accuracy, suggesting that for optimal results, different types of scanners should be applied to specific clinical applications and medical problems according to their special construction designs and characteristics.

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Transcatheter aortic valve implantation (TAVI) is a minimally invasive procedure to treat severe aortic valve stenosis. As an emerging imaging technique, C-arm computed tomography (CT) plays a more and more important role in TAVI on both pre-operative surgical planning (e.g., providing 3-D valve measurements) and intra-operative guidance (e.g., determining a proper C-arm angulation). Automatic aorta segmentation and aortic valve landmark detection in a C-arm CT volume facilitate the seamless integration of C-arm CT into the TAVI workflow and improve the patient care. In this paper, we present a part-based aorta segmentation approach, which can handle structural variation of the aorta in case that the aortic arch and descending aorta are missing in the volume. The whole aorta model is split into four parts: aortic root, ascending aorta, aortic arch, and descending aorta. Discriminative learning is applied to train a detector for each part separately to exploit the rich domain knowledge embedded in an expert-annotated dataset. Eight important aortic valve landmarks (three hinges, three commissures, and two coronary ostia) are also detected automatically with an efficient hierarchical approach. Our approach is robust under all kinds of variations observed in a real clinical setting, including changes in the field-of-view, contrast agent injection, scan timing, and aortic valve regurgitation. Taking about 1.1 s to process a volume, it is also computationally efficient. Under the guidance of the automatically extracted patient-specific aorta model, the physicians can properly determine the C-arm angulation and deploy the prosthetic valve. Promising outcomes have been achieved in real clinical applications.

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OBJECTIVES: The purpose of this study was to investigate the evolution of patient selection criteria for transcatheter aortic valve implantation (TAVI) and its impact on clinical outcomes. BACKGROUND: Anecdotal evidence suggests that patient selection for TAVI is shifting toward lower surgical risk patients. The extent of this shift and its impact on clinical outcomes, however, are currently unknown. METHODS: We conducted a single-center study that subcategorized TAVI patients into quartiles (Q1 to Q4) defined by enrollment date. These subgroups were subsequently examined for differences in baseline characteristics and 30-day and 6-month mortality rate. The relationship between quartiles and mortality rate was examined using unadjusted and adjusted (for baseline characteristics) Cox proportional hazard models. RESULTS: Each quartile included 105 patients (n = 420). Compared with Q4 patients, Q1 patients had higher logistic EuroSCORES (25.4 ± 16.1% vs. 17.8 ± 12.0%, p < 0.001), higher Society of Thoracic Surgeons scores (7.1 ± 5.5% vs. 4.8 ± 2.6%, p > 0.001), and higher median N-terminal pro-B-type natriuretic peptide levels (3,495 vs. 1,730 ng/dl, p < 0.046). From Q1 to Q4, the crude 30-day and 6-month mortality rate decreased significantly from 11.4% to 3.8% (unadjusted hazard ratio [HR]: 0.33; 95% confidence interval [CI]: 0.11 to 1.01; p = 0.053) and from 23.5% to 12.4% (unadjusted HR: 0.49; 95 CI: 0.25 to 0.95; p = 0.07), respectively. After adjustment for baseline characteristics, there were no significant differences between Q1 and Q4 in 30-day mortality rate (adjusted HR ratio: 0.29; 95% CI: 0.08 to 1.08; p = 0.07) and 6-month mortality rate (HR: 0.67; 95% CI: 0.25 to 1.77; p = 0.42). CONCLUSIONS: The results of this study demonstrate an important paradigm shift toward the selection of lower surgical risk patients for TAVI. Significantly better clinical outcomes can be expected in lower than in higher surgical risk patients undergoing TAVI.

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With an aging population, improvement in life expectancy, and significant increase in the use of bioprosthetic valves, structural valve deterioration will become more and more prevalent. The operative mortality for an elective redo aortic valve surgery is reported to range from 2% to 7%, but this percentage can increase to more than 30% in high-risk and nonelective patients. Because transcatheter aortic valve (TAV)-in-surgical aortic valve (SAV) implantation represents a minimally invasive alternative to conventional redo surgery, it may prove to be safer and just as effective as redo surgery. Of course, prospective comparisons with a large number of patients and long-term follow-up are required to confirm these potential advantages. It is axiomatic that knowledge of the basic construction and dimensions, radiographic identification, and potential failure modes of SAV bioprostheses is fundamental in understanding key principles involved in TAV-in-SAV implantation. The goals of this paper are: 1) to review the classification, physical characteristics, and potential failure modes of surgical bioprosthetic aortic valves; and 2) to discuss patient selection and procedural techniques relevant to TAV-in-SAV implantation.

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OBJECTIVES: This study sought to review the acute procedural outcomes of patients who underwent transcatheter aortic valve (TAV)-in-surgical aortic valve (SAV) implantation at the German Heart Center, Munich, and to summarize the existing literature on TAV-in-SAV implantation (n = 47). BACKGROUND: There are several case reports and small case series describing transcatheter aortic valve implantation for a failing surgical aortic valve bioprosthesis (TAV-in-SAV implantation). METHODS: From January 2007 to March 2011, 20 out of 556 patients underwent a TAV-in-SAV implantation at the German Heart Center Munich. Baseline characteristics and clinical outcome data were prospectively entered into a dedicated database. RESULTS: The mean patient age was 75 ± 13 years, and the mean logistic European System for Cardiac Operative Risk Evaluation and Society of Thoracic Surgeons' Risk Model scores were 27 ± 13% and 7 ± 4%, respectively. Of the 20 patients, 14 had stented and 6 had stentless surgical bioprostheses. Most cases (12 of 20) were performed via the transapical route using a 23-mm Edwards Sapien prosthesis (Edwards Lifesciences, Irvine, California). Successful implantation of a TAV in a SAV with the patient leaving the catheterization laboratory alive was achieved in 18 of 20 patients. The mean transaortic valve gradient was 20.0 ± 7.5 mm Hg. None-to-trivial, mild, and mild-to-moderate paravalvular aortic regurgitation was observed in 10, 6, and 2 patients, respectively. We experienced 1 intraprocedural death following pre-implant balloon aortic valvuloplasty ("stone heart") and 2 further in-hospital deaths due to myocardial infarction. CONCLUSIONS: TAV-in-SAV implantation is a safe and feasible treatment for high-risk patients with failing aortic bioprosthetic valves and should be considered as part of the armamentarium in the treatment of aortic bioprosthetic valve failure.

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BACKGROUND: Acute kidney injury (AKI) can occur in up to one third of patients after surgical aortic valve replacement and can be associated with increased mortality. Little data exist, however, about the incidence, predictors, and prognostic implications of AKI after transcatheter aortic valve implantation (TAVI). OBJECTIVES: The aim of this study was to examine the incidence, predictors, and prognostic implications of AKI after TAVI. METHODS: Between January 2007 and January 2010, we prospectively enrolled 234 consecutive patients who underwent TAVI with the Medtronic CoreValve System (Medtronic CoreValve, Minneapolis, Minnesota) or Edwards SAPIEN (Edwards Lifesciences, Inc, Irvine, CA) heart valve. Acute kidney injury was defined according to the risk, injury, failure, loss, end-stage criteria. Patients with preoperative end-stage renal failure requiring dialysis were excluded. Baseline characteristics and procedural-related factors were examined as predictors for AKI in a multivariable regression model. RESULTS: Acute kidney injury was identified in 46 (19.6%) of 234 patients, and 24 (10.3%) of 234 patients required renal replacement therapy. The unadjusted in-hospital mortality rate was 15.2% in those patients without AKI and 7.7% in those with AKI (P = .015). Univariable logistic regression analysis identified preoperative serum creatinine, preoperative blood urea nitrogen, peripheral vascular disease, and blood transfusion to be associated with AKI. Preoperative serum creatinine level remained as the only independent predictor of AKI (OR 3.7 95%, CI 1.24-11.3, P = .019). The amount of contrast used (in milliliters) was not associated with AKI (OR 1.8 95%, CI 0.94-3.5, P = .07). CONCLUSION: In this study, we observed that one fifth of patients developed AKI after TAVI and that AKI was associated with increased in-hospital mortality. Preoperative serum creatinine level was identified as the only predictor of AKI.

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C-arm CT is an emerging imaging technique in transcatheter aortic valve implantation (TAVI) surgery. Automatic aorta segmentation and valve landmark detection in a C-arm CT volume has important applications in TAVI by providing valuable 3D measurements for surgery planning. Overlaying 3D segmentation onto 2D real time fluoroscopic images also provides critical visual guidance during the surgery. In this paper, we present a part-based aorta segmentation approach, which can handle aorta structure variation in case that the aortic arch and descending aorta are missing in the volume. The whole aorta model is split into four parts: aortic root, ascending aorta, aortic arch, and descending aorta. Discriminative learning is applied to train a detector for each part separately to exploit the rich domain knowledge embedded in an expert-annotated dataset. Eight important aortic valve landmarks (three aortic hinge points, three commissure points, and two coronary ostia) are also detected automatically in our system. Under the guidance of the detected landmarks, the physicians can deploy the prosthetic valve properly. Our approach is robust under variations of contrast agent. Taking about 1.4 seconds to process one volume, it is also computationally efficient.

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OBJECTIVES: The aim of this study was to identify risk factors for new-onset atrioventricular (AV) block requiring pacemaker (PM) implantation after transcatheter aortic valve implantation (TAVI). BACKGROUND: High-grade AV block and consecutive PM implantation are frequent complications following TAVI. METHODS: For logistic regression analysis, we included 159 patients (mean age: 81 +/- 6 years, EuroSCORE: 22 +/- 13%) who underwent TAVI (n = 116 transfemoral, n = 4 via subclavian artery, n = 37 transapical, n = 2 transaortic) between June 2007 and January 2009 and who had no previously implanted PM. RESULTS: Thirty-five patients (22%) developed new-onset post-operative AV block with the need of PM implantation. Logistic regression revealed a 2-fold increased risk for new-onset AV block in patients in whom a large valve is implanted in a small annulus (32% pacemaker implantations, odds ratio [OR]: 2.378, p = NS), a 4-fold increased risk with the implantation of the CoreValve (Medtronic, Minneapolis, Minnesota) versus the Edwards Sapien valve (Edwards Lifesciences, Irvine, California) (27% pacemaker implantations, OR: 3.781, p = NS), and a 5-fold increased risk for patients who exhibit an AV block episode instantly during the implantation procedure (49% pacemaker implantations, OR: 4.819, p = 0.001). Pre-existing ECG alterations were not identified as risk factors for AV block after transcatheter aortic valve implantation. CONCLUSIONS: We assume that conduction tissue impairment is provoked by mechanical compression with large prostheses in smaller annuli or in the larger area of the CoreValve covering the outflow tract and may appear instantly during the implantation procedure. Continuous post-operative electrocardiogram monitoring should be performed for at least 3 days in all patients after TAVI procedures and until discharge in patients with increased risk for this complication.

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The LIFEBRIDGE B2T is a new portable cardiopulmonary bypass (CPB) system designed for temporary circulatory support. The LIFEBRIDGE B2T consists of a disposable patient unit with a CPB circuit, a control, and a base unit. The system weighs 20 kg. We used the LIFEBRIDGE B2T in four patients for circulatory support in beating heart coronary artery bypass graft for complete revascularization. The LIFEBRIDGE B2T was connected via femoral cannulation. Concentrations of free hemoglobin (fHb), interleukin (IL)-6, and -8 were measured. For venous blood drainage, 22-24 Fr cannulae and for arterial cannulation, 16-20 Fr cannulae were used. Average extracorporeal circulation (ECC) time was 61 +/- 18 minutes. During circulatory support, the system delivered an arterial blood flow between 3.1 and 4.1 L/min. The negative pressure at the venous drainage was between -79 and -45 mm Hg. During circulatory support, fHb concentration increased from 5.8 +/- 1.7 mg/dL to a maximum of 10.2 +/- 6.2 mg/dL. Also, IL-6 and -8 increased from 2.1 +/- 0.06 to 503.3 +/- 400.7 U/L and 5.9 +/- 0.9 to 66.5 +/- 46.8 U/L, respectively. The LIFEBRIDGE B2T is a new portable and safe circulatory support system. Connected via femoral cannulation, the system provides adequate arterial blood flow and an acceptable negative pressure at the venous cannula. The fHb concentration showed only a moderate increase during ECC.

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OBJECTIVE: Advocates of pulsatile flow postulate that the flow pattern during extracorporeal circulation (ECC) should be similar to the physiological one. However, the waveforms generated by clinically used pulsatile pumps are by far different from the physiological ones. Therefore, we constructed a new computer-controlled pulsator which can provide nearly physiological perfusion patterns during ECC. We compared its effect (group 1) with pulsatile (group 2) and non-pulsatile (group 3) perfusion generated by a conventional roller pump. METHODS: Thirty pigs (10 per group) underwent 180 min ECC with an aortic cross-clamp time of 120 min. Pulse pressure, peak aortic flow, dp/dt(max), pulsatility index and energy-equivalent pressure were measured online. Renal and intestinal blood flow was calculated by fluorescent microspheres. The inflammatory response was assessed by the level of interleukin 6/1ra, the haemolysis by the free haemoglobin, and the escape rate of plasma protein by the disappearance rate of Evans Blue dye. RESULTS: When compared to the preoperative curves, pulsatile waveforms during ECC were similar in group 1 and severely damped in group 2. Inflammatory response increased without significant differences between the groups. There were no differences between groups in renal and bowel blood flow. Free haemoglobin after ECC was higher in the pulsatile groups (group 1=43+/-144 mg dl(-1), group 2=40+/-164 mg dl(-1), group 3=11+/-4mgdl(-1); group 1 vs 2 (ns); group 1 or 2 vs 3 (p<0.001)). The escape rate of Evans Blue increased after ECC in group 1 1.8-fold (p<0.05), in group 2 1.45-fold (p<0.05) and in group 3 1.27-fold (ns). CONCLUSION: Even when using pulsatile flow patterns which mimic closely the physiological waveforms, there is no advantage concerning organ perfusion or inflammatory response. Moreover, the extent of haemolysis and capillary leak is higher compared to non-pulsatile perfusion. Efforts to optimise pulsatility are not justified.

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Homograft implantation in the pulmonary position is usually part of initial repair in congenital heart defects with dysplasia or atresia of the pulmonary valve and at the time of the Ross operation. As part of reoperations, homografts are mainly required after nonvalved right ventricular outflow tract procedures. Due to an annual increase of homograft dysfunction, replacement is inevitable. Recently, percutaneous catheter-based valve implantations gain increasing acceptance. Even transventricular pulmonary valve implantation has been reported. Prior to decision making for any surgical or interventional therapy, the right ventricular outflow tract morphology together with additional pathologies need to be assessed. With the development of new prostheses and delivery modes, the demand for conventional surgery will further decrease.

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Sternal dehiscence after median sternotomy can be a challenging problem in case of multiple fractures or infection. For sternal refixation, the principles of rigid plate and screw osteosynthesis gained from orthopedic surgery have been recommended by several authors. We present a new system for sternal reconstruction consisting of reconstruction plates, steel cables, and cannulated screws.

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The analysis of baroreflex sensitivity (BRS) and heart rate variability (HRV) leads to additional insights into patients' prognosis after cardiovascular events. The following study was performed to assess the differences in the post-operative recovery of autonomic regulation after mitral valve (MV) and aortic valve (AV) surgery with a heart-lung machine. Among the 43 consecutive male patients enrolled in a prospective study, 26 underwent isolated AV surgery and 17 isolated MV surgery. Blood pressure as well as ECG signals were recorded the day before, 24 hours after and one week after surgery. BRS was calculated according to the dual sequence method, and HRV was calculated using standard linear as well as nonlinear parameters. There were no major differences between the two groups in the pre-operative values. At 24 hours a comparable depression of HRV and BRS in both groups was observed, while at 7 days there was partial recovery in AV patients, which was absent in MV patients: p(AV versus MV)<0.001. While the response of the autonomic system to surgery is similar in AV and MV patients, there is obviously a decreased ability to recover in MV patients, probably attributed to traumatic lesions of the autonomic nervous system by opening the atria. Ongoing research is required for further clarification of the pathophysiology of this phenomenon and to establish strategies to restore autonomic function.

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OBJECTIVE: Sternal dehiscence after median sternotomy can be a challenging problem in case of multiple fractures or infection. The use of titanium plates is a promising approach for sternal reconstruction. METHODS: Titanium plate fixation was used in 15 patients (67+/-5.9 years, 171+/-8.2 cm, 93.6+/-14.9 kg, body mass index 32+/-5 kg/m(2)) with unstable thorax after failed attempts of sternal closure and patients in whom failure of conventional rewiring would be expected due to one or more serious risk factors (e.g. multiple fractures or loss of sternum, excessive overweight). In six patients, one of whom had an infection, the Synthes Titanium Sternal Fixation System was used as transverse plate fixation (series 1). In nine other patients, longitudinal titanium plating of the sternum was performed with 2.4mm Synthes locking reconstruction plates, which were cross-connected by wires (series 2). In six of these patients the cross-connection was reinforced by additional short transverse plates. In series 2, sternal instability was complicated by multiple fragments of sternum (n=8) and/or infection (n=3). In case of infection, initial debridement was performed with consecutive antibiotic and topical negative pressure therapy (median 13 days). Clinical examination was done 3-12 months postoperatively. RESULTS: Mean operation time was 133+/-21 min (series 1) and 110+/-12 min (series 2). Transverse plating required more extensive mobilization of pectoral muscle. All patients had an uneventful early postoperative course and were extubated 5.1+/-5.9h (median 4 h) after surgery. Postoperatively, all patients had a stable thorax, but in the long-term three patients from series 1 complained of plate-related pain during breathing, with the subsequent need of plate removal. One multi morbid patient from series 1 died on the 31st postoperative day. The cause of death was not related to the sternal plate refixation. CONCLUSION: Titanium plate fixation is an effective method to stabilize complicated sternal dehiscence. The longitudinal plating technique is easier to apply and seems to be associated with fewer complications.

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We present a case of a 66-year-old diabetic patient with chronic non-healing sternum after CABG operation. After four attempts of sternum refixation within 2 years, the need of bone debridement resulted in a nearly complete loss of sternum. Finally, a mesh graft and a pectoralis muscle flap were used to bridge the sternal space. Despite good wound healing, the thoracic instability led to intolerable chest pain persisting over the next years. In this case report, we describe the successful thoracic stabilization by using transverse plate fixation, which resulted in perfect thoracic stabilization and immediate cessation of pain.

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BACKGROUND: Atrial fibrillation (AF) occurs in 20-40% of patients after open heart surgery and leads to an increased morbidity and prolonged hospital stay. Earlier studies have demonstrated that depressed baroreflex function predicts mortality and major arrhythmic events in patients surviving myocardial infarction. Cardiac surgery per se leads to decreased baroreflex sensitivity (BRS) and heart rate variability (HRV). Hence, the present study was aimed at analyzing the impact of the cardiovascular autonomous system on the development of postsurgical AF. METHODS AND RESULTS: The study covered 51 patients who consecutively underwent aortic valve replacement, coronary artery bypass surgery, or combined procedures. Noninvasive blood pressure and ECG were recorded the day before and 24 hour after surgery. BRS, linear as well as nonlinear HRV parameters were calculated using established methods. Eighteen patients developed AF during the first postoperative week, while 33 remained in sinus rhythm (SR) throughout the observation period. Patients with postoperative (PostOp) AF exhibited a significantly reduced preoperative (PreOp) BRS in terms of bradycardic and tachycardic regulation (average delayed slope [ms/mmHg]: SR: PreOp: 9.83 +/- 3.26, PostOp: 6.02 +/- 2.29, Pre-Post: P < 0.001; AF: PreOp: 7.59 +/- 1.99, PostOp: 6.39 +/- 3.67, Pre-Post: P < 0.044; AF vs SR: PreOp: P < 0.01, PostOp: ns). In both groups, surgery caused a decrease of BRS and HRV. Analysis of nonlinear dynamics revealed a tendency toward decreased system complexity caused by the operation; this trend was significant in patients remaining in sinus rhythm. CONCLUSIONS: Patients experiencing postoperative AF obviously suffer from an impaired BRS before surgery already. These findings may be used to guide prophylactic antiarrhythmic therapy.

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The anatomic conditions of the female breast require imaging the breast region 3-dimensionally in a normal standing position for quality assurance and for surgery planning or surgery simulation. The goal of this work was to optimize the imaging technology for the mammary region with a 3-dimensional (3D) laser scanner, to evaluate the precision and accuracy of the method, and to allow optimum data reproducibility. Avoiding the influence of biotic factors, such as mobility, we tested the most favorable imaging technology on dummy models for scanner-related factors such as the scanner position in comparison with the torso and the number of scanners and single shots. The influence of different factors of the breast region, such as different breast shapes or premarking of anatomic landmarks, was also first investigated on dummies. The findings from the dummy models were then compared with investigations on test persons, and the accuracy of measurements on the virtual models was compared with a coincidence analysis of the manually measured values. The best precision and accuracy of breast region measurements were achieved when landmarks were marked before taking the shots and when shots at 30 degrees left and 30 degrees right, relative to the sagittal line, were taken with 2 connected scanners mounted with a +10-degree upward angle. However, the precision of the measurements on test persons was significantly lower than those measured on dummies. Our findings show that the correct settings for 3D imaging of the breast region with a laser scanner can achieve an acceptable degree of accuracy and reproducibility.

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