[Recurrent intracerebral haemorrhage in a 24-year-old female patient]. / Rezidivierende intrazerebrale Blutungen bei einer 24-jährigen Patientin.

A 24-year-old female patient from Sierra Leone was referred to the authors' hospital after several unclear intracerebral bleeding events and an echogenic structure on the aortic valve. The patient was receiving oral anticoagulation therapy due to paroxysmal atrial fibrillation and left ventricular noncompaction. Fluorescence in situ hybridization in combination with polymerase chain reaction and sequencing revealed infective endocarditis of the mitral and aortic valve caused by Bartonella quintana. In retrospect, the intracerebral bleeding events could be identified as septic emboli with secondary haemorrhagic transformation under anticoagulation therapy. The patient showed significant clinical improvement and no further bleeding events occurred after receiving biological mitral and aortic valve replacement and several weeks of doxycycline and gentamicin antibiotic therapy.

Interdisciplinary consensus on indications for transfemoral transcatheter aortic valve implantation (TF-TAVI) : Joint Consensus Document of the Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte e.V. (ALKK) and cooperating Cardiac Surgery Departments.

Indications for TF-TAVI (transfemoral transcatheter aortic valve implantation) are rapidly changing according to increasing evidence from randomized controlled trials. Present trials document the non-inferiority or even superiority of TF-TAVI in intermediate-risk patients (STS-Score 4-8%) as well as in low-risk patients (STS-Score < 4%). However, risk scores exhibit limitations and, as a single criterion, are unable to establish an appropriate indication of TF-TAVI vs transapical TAVI vs SAVR (surgical aortic valve replacement). The ESC (European Society of Cardiology)/EACTS (European Association for Cardio-Thoracic Surgery) guidelines 2017 and the German DGK (Deutsche Gesellschaft für Kardiologie)/DGTHG (Deutsche Gesellschaft für Thorax-, Herz- und Gefäßchirurgie) commentary 2018 offer a framework for the selection of the best therapeutic method, but the individual decision is left to the discretion of the heart teams. An interdisciplinary TAVI consensus group of interventional cardiologists of the ALKK (Arbeitsgemeinschaft Leitende Kardiologische Krankenhausärzte e.V.) and cardiac surgeons has developed a detailed consensus on the indications for TF-TAVI to provide an up-to-date, evidence-based, comprehensive decision matrix for daily practice. The matrix of indication criteria includes age, risk scores, contraindications against SAVR (e.g., porcelain aorta), cardiovascular criteria pro TAVI, additional criteria pro TAVI (e.g., frailty, comorbidities, organ dysfunction), contraindications against TAVI (e.g., endocarditis) and cardiovascular criteria pro SAVR (e.g., bicuspid valve anatomy). This interdisciplinary consensus may provide orientation to heart teams for individual TAVI-indication decisions. Future adaptations according to evolving medical evidence are to be expected. Interdisciplinary consensus on indications for transfemoral transcatheter aortic valve implantation (TF-TAVI).

The mosaic bioprosthesis in the aortic position: hemodynamic performance after 2 years.

BACKGROUND: The Mosaic bioprosthesis is a porcine valve combining several new features to improve hemodynamics and durability: a low profile stent for reduced flow obstruction, zero pressure fixation to maintain the natural collagen crimp, and the amino oleic acid antimineralization treatment to enhance durability. METHODS: Fifty-five Mosaic valves were implanted in the aortic position since February 1994. Data from these patients (group 1) were compared with data from 52 patients who had received a Hancock Modified Orifice II aortic valve (group 2). The mean patient age was 72.0 (+/-5.9) years for group 1 and 76.8 (+/-4.7) years for group 2. Clinical examinations including transthoracic echocardiography were performed 6 and 24 months postoperatively. RESULTS: Mild aortic insufficiencies were found in 2 patients in group 1 and in 3 patients in group 2. There were no embolic or bleeding complications. One Mosaic patient required reoperation due to mitral insufficiency. During the reoperation, a small (approximately 3 mm) thrombus was noted on the outflow side of a Mosaic cusp. The valve was removed and replaced prophylactically. In the 2-year follow-up, hemodynamic measurements showed mean pressure gradients of 12.4 mm Hg for the 21 mm, 11.3 mm Hg for the 23 mm, and 15.4 mm Hg for the 25 mm prostheses in the Hancock group. In the Mosaic group, mean pressure gradients were 14.8 mm Hg for the 21 mm, 10.9 mm Hg for the 23 mm, and 11.5 mm Hg for the 25 mm valves. Differences between pressure gradients and effective orifice areas of the Hancock and the Mosaic valves were not statistically significant. Early mortality in group 1 was 3.6% and in group 2 3.8%. Overall mortality was 12.7% and 13.5%, respectively. CONCLUSIONS: The Mosaic valve has low pressure gradients for all sewing ring diameters. Compared with the Hancock Modified Orifice valve, there was no statistically significant gradient difference but a tendency toward better hemodynamics was noted in the Mosaic group after 2 years.

The Mosaic bioprosthesis in the aortic position at five years.

BACKGROUND AND AIM OF THE STUDY: The study aim was to collect intermediate-term data on the Mosaic bioprosthesis implanted in the aortic position. The device has been in clinical use since February 1994. METHODS: The Mosaic bioprosthesis is a stented porcine aortic valve, which combines a zero pressure differential fixation technique and anti-mineralization treatment with amino oleic acid for improved tissue durability. Between February 1994 and May 1999, 100 patients (49 females, 51 males; mean age at implant 73.4 +/- 7.3 years (range: 31-87 years) underwent aortic valve replacement with the Mosaic prosthesis in our department. Concomitant procedures were performed in 40% of cases. Patients were followed up prospectively at annual intervals; the mean follow up was 2.7 years (total 273.7 patient-years (pt-yr)) and was 100% complete. RESULTS: Total early mortality (within 30 days) was 3.0%; the late mortality rate was 4.4%/pt-yr and included a valve-related mortality rate of 0.7%/pt-yr. The freedom from event rates at five years were 97.3 +/- 1.9% for permanent neurological, 99.0 +/- 1.0% for transient neurological, 95.9 +/- 3.2 for thrombosed prosthesis, 95.6 +/- 2.2% for anti-thromboembolic-related hemorrhage, 100% for primary valvular leak, 96.9 +/- 3.0% for non-structural dysfunction, 100% for endocarditis, and 92.0 +/- 4.9% for explant. The mean systolic gradients were 15.2, 13.1 and 10.1 mmHg for the 21, 23 and 25 mm valve sizes, respectively. CONCLUSION: The clinical and hemodynamic performance of the Mosaic prosthesis was highly satisfactory during the first five years after clinical introduction. Further data will be necessary to confirm long-term durability.

Intraoperative local fibrinolysis as emergency therapy after early coronary artery bypass thrombosis.

OBJECTIVE: Acute graft occlusion early postoperatively after coronary artery bypass grafting (CABG) is a rare but dramatic complication, frequently making resuscitation necessary. Emergency reoperation with reanastomosing of the concerning grafts is the normal procedure to restrict the otherwise unavoidable myocardial damage. Mortality in these cases is up to 50%. Due to this unsatisfying situation, we perform since 1995 in such cases an adjuvant intraoperative intracoronary installed fibrinolysis with recombinant tissue type plasminogen activator (rt-PA; alteplase). METHODS: Between 1/1994 and 8/1998, 4231 patients underwent CABG. In 18 of these patients, emergency reoperation within the first 12 h after CABG due to clinical signs of acute myocardial infarction was necessary. In nine of the patients (group II) additionally intraoperative rt-PA lysis of the involved vessel/s has been performed. When the peripheral anastomosis was reopened and the thrombotic material was removed, we inserted for this a left atrial-catheter (LA-catheter) of 1.2 mm in diameter, into the coronary artery. Then we administered within 3-5 min, up to 100 mg rt-PA (t1/2: 5-9 min.) locally into the vessel. All patients were treated postoperatively with acetylsalicyl acid (ASA) and heparine. RESULTS: In group I (n = 9; seven males, two females) without thrombolytic therapy, 78% of the patients (n = 7) could not have been prevented from large myocardial infarction despite emergency reoperation. Three of these patients died during or early after reintervention. In group II with fibrinolytic therapy (n = 9) three of the patients developed Q-wave myocardial infarction following reoperation. None of the patients died. Creatinkinase maximum were in group I significantly higher than in group II (group I: CK = 1254 units/I, CK-MB = 197 units/l; group II: CK = 502 units/l, CK-MB = 61 units/l; P < 0.01). Postoperative bleeding was considerable elevated in both groups. In group I, 832 ml/24 h (375-1420 ml), in group II 1164 ml/24 h (520-1560 ml). Lysis-associated complications were not observed. CONCLUSIONS: Reoperation of patients with acute thrombotic bypass occlusion after CABG is characterized by a high mortality and morbidity. If additionally fibrinolysis is performed, a sufficient myocardial perfusion seems to be restored. A short half-life in combination with the presented non-systemic application technique of rt-PA seem to prevent unpredictable bleeding. Rt-PA lysis apparently contributes very effectively to the restoration of the macro- and microcirculation within the infarct-related area. Thrombolytic therapy during cardiac surgery with rt-PA is feasible, its application easy and harmful complications are not seen.

Acute mesenteric ischemia after open heart surgery.

Acute mesenteric ischemia is a rare but severe complication after open heart surgery. Its incidence (0.2-0.4%) is quite low, but mortality rates are ranging between 70% and 100%. From October 1992 to December 1996, 4,640 patients underwent open heart surgery with cardiopulmonary bypass: 74.6% coronary artery bypass graft (CABG) operations, 23.2% valve replacement including aortic repairs, and 2.2% corrections of congenital heart diseases or tumors of the heart. The overall mortality rate (30 days) was 3.4%, and after CABG, 2.9%. Twelve patients (0.26%), following CABG (one combined with aortic valve replacement, one with mitral reconstruction, and one with carotid disobliteration) developed signs of acute mesenteric ischemia in the early postoperative period (day 1 to 5). In all patients various abdominal symptoms, leukocytosis, acidosis, hyperlactatemia, hyperosmolality, renal failure, and, finally, hemodynamic instability were observed. Eleven patients underwent emergency laparotomy. Mesenteric angiography was done if possible in still stable patients (n=7); it showed severe stenosis or occlusion prior to the operation in each case. Other diagnostic methods were not reliable. In six patients (55%) during the first look, extensive bowel necrosis was found and in five patients an ischemic intestine but no necrosis was detected. Of these, three patients were affected by extensive bowel gangrene at the second look. In the fourth patient a disseminated peripheral ischemia of the entire small intestine was found intraoperatively. After mechanical release and stimulation normal bowel function could be reestablished. One patient underwent percutaneous transluminal angioplasty prior to the laparotomy. Bowel perfusion was still deteriorated but no necrosis was found intraoperatively. These patients were the only survivors in the investigated group; 10 of 12 patients (83.3%) died in the early postoperative period (day 1 to day 6). Predisposing factors for mesenteric ischemia are: arteriosclerotic patients after CABG (100%), age >70 years (91.7%), hyperosmotic dehydration (100%), and cardiac ischemia in 25%. Mesenteric ischemia is a fatal complication with high mortality rates after open heart surgery, especially in older, dehydrated patients with generalized atherosclerotic vessel disease. As the acute mesenteric ischemia usually starts during anesthesia or in the early postoperative period, setting of immediate diagnosis is very difficult. With the occurrence of typical symptoms diagnostic and therapeutic procedures (angiography and laparotomy) must be done very urgently owing to the life-threatening mesenteric process. When mesenteric gangrene already has taken place, the prognosis is very poor, despite extensive resection. Prevention can be exercised by avoiding perioperative hyperosmotic dehydration of patients at high risk.

MSCT guided sizing of the Edwards Sapien XT TAVI device: impact of different degrees of oversizing on clinical outcome.

AIMS: Prospective data on the usage of 3-dimensional imaging based annulus sizing on the outcome of TAVI is not available yet and there is general uncertainty about the optimal degree of oversizing. In the current study we therefore assessed a 3-D MSCT guided over-sizing approach and evaluated the clinical outcome of different degrees of oversizing. METHODS: TAVI-size-selection was done using systolic MSCT-annulus cross-sectional-area (CSA) measurements in 107 patients with severe aortic stenosis with the goal to oversize the 3rd generation balloon expandable Edwards Sapien XT (ESTV) device in relation to the native aortic annulus CSA. RESULTS: Among different degrees of oversizing there were no differences in the occurrence of stroke, myocardial infarction and death. No aortic injuries were observed. The overall rate of >mild postprocedural aortic regurgitation (PAR) was 7.6%. Increasing oversizing ratios are associated with lower rates of >mild PAR (r = -0.236, p<0.02) with the lowest rate of >mild PAR in patients with area based oversizing ratios >25% and the highest rate in patients with oversizing ratios <15% (0% vs. 15.8%, p<0.02). The rate of postprocedural permanent pacemakers tended to be lower in patients with <15% oversizing compared to those with >25% oversizing (5.3 vs. 16.7%, p<0.23). CONCLUSIONS: MSCT guided ESTV-device sizing is safe and is associated with significantly lower than previously reported rates for PAR. A device/annulus oversizing ratio of 15-25% based on area and 7-12% based on mean diameter appears to provide the best risk-benefit ratio in terms of PAR reduction and conduction disorders.

[Aortic valve stenosis: transcatheter aortic valve implantation (TAVI) ­ transarterial or transapical approach]. / Aortenklappenstenosen: Kathetergestützte Aortenklappenimplantation (TAVI) ­ transarterieller oder transapikaler Zugang.

The calcified aortic stenosis is the dominating valve disease. Patients affected are most common elderly people in the 8 (th) or 9 (th) decade of their life who often show associated comorbidities like reduced left ventricular function, impaired renal function, pulmonary hypertension, and further diseases (Diabetes mellitus, stroke, COPD). In many cases perioperative morbidity and mortality are too high for surgical valve replacement and up to 30 % of patients are rejected. Nevertheless, prognosis of aortic stenosis is worse if the typical symptoms like dyspnea on exertion, syncope, and angina occur. The transcatheter aortic valve implantation is a new method treating this particular group of patients. The aortic valve bioprothesis consists of a balloon-expandable stent or a self-expandable frame, in which a valve of bovine or porcine pericardium is incorporated. The implantation is performed by retrograde access via the femoral or subclavian artery; the balloon-expandable prosthesis can also be implanted by transapical approach. Recently, the PARTNER trial and other studies demonstrate a high implantation success rate and better survival in comparison to standard therapy but exhibit also cerebral vascular and peripheral vascular complications. A further reduction of the available delivery systems and new types of valves which are under experimental tests and clinical evaluation contribute to this development.

Impact of patient-prosthesis mismatch on exercise capacity in patients after bioprosthetic aortic valve replacement.

OBJECTIVE: It is presumed that patient-prosthesis mismatch (PPM) influences morbidity and mortality after aortic valve replacement (AVR). The aim of our study was to determine the impact of PPM on physical capacity. METHODS: Six months after AVR with a bioprosthesis, stress echocardiography was performed on a bicycle ergometer in 312 patients. Depending on gender, age and weight, the target exercise level for every patient was determined by a reference table. Maximum achieved workload is given as percentage of the predicted exercise capacity (PPEC). PPM was defined as an effective orifice area index

Spatial and temporal variations in inhalable CuZnPb aerosols within the Mexico City pollution plume.

We report on the CuPbZn content of PM10 and PM2.5 samples collected from three sites (urban T0, suburban T1 and rural T2) during the Mexico City MILAGRO campaign of March 2006. Daytime city centre concentrations of summation operator CuZnPb(PM10) were much higher (T0 > 450 ng m(-3)) than at the suburban site (T1 < 200 ng m(-3)). Rural site (T2) summation operator CuZnPb(PM10) concentrations exceeded 50 ng m(-3) when influenced by the megacity plume but dropped to 10 ng m(-3) during clean northerly winds. Nocturnal metal concentrations more than doubled at T0, as pollutants became trapped in the nightly inversion layer, but decreased at the rural site. Transient spikes in concentrations of different metals, e.g. a "copper event" at T0 (CuPM10 281 ng m(-3)) and "zinc event" at T1 (ZnPM10 1481 ng m(-3)) on the night of March 7-8, demonstrate how industrial pollution sources produce localised chemical inhomogeneities in the city atmosphere. Most metal aerosols are <2.5 microm and SEM study demonstrates the dominance of Fe, Ti, Ba, Cu, Pb and Zn (and lesser Sn, Mo, Sb, W, Ni, V, As, Bi) in metalliferous particles that have shapes including spherical condensates, efflorescent CuZnClS particles, cindery Zn, and Cu wire. Metal aerosol concentrations do not change in concert with PM10 mass, which is more influenced by wind resuspension than industrial emissions. Metalliferous particles can induce cell damage, and PM composition is probably more important than PM mass, with respect to negative health effects, so that better monitoring and control of industrial emissions would likely produce significant improvements in air quality.

Hemodynamic performance and incidence of patient-prosthesis mismatch of the complete supraannular perimount magna bioprosthesis in the aortic position.

BACKGROUND: Complete supraannular placement and smaller stent design allow the implantation of a Perimount Magna bioprosthesis with a larger inner diameter than that of a standard Perimount. This study compares the hemodynamic performance and the incidence of patient-prosthesis mismatch (PPM) of both prostheses. METHODS: 128 patients underwent aortic valve replacement, receiving either a Magna (n = 57) or a standard (n = 71) prosthesis. Inner aortic annulus diameter was measured intraoperatively by a hegar dilator to match echocardiographically obtained results to the annulus diameter instead of matching them to labelled valve size. RESULTS: The Magna was significantly superior with respect to mean pressure gradient and effective orifice area in patients with an annulus diameter of 22-23 mm. In patients with an annulus diameter < 22 mm or > 23 mm, there was a non-significant trend towards superior hemodynamics in the Magna group. Severe PPM (effective orifice area index < or = 0.65 cm (2)/m (2)) was present in 11.1% (Magna) vs. 42.1% (Standard) of patients with an annulus diameter < 22 mm; in 0% (Magna) vs. 13.8% (Standard) with an annulus diameter of 22-23 mm; no PPM was seen in patients with annulus diameter > 23 mm in both groups. CONCLUSIONS: The Perimount Magna had a significantly reduced incidence of patient-prosthesis mismatch and superior hemodynamics compared to the standard Perimount.

[Mosaic bioprosthesis after 5 years]. / Mosaic-Bioprothese nach fünf Jahren.

The Mosaic bioprosthesis is a stented porcine aortic valve, which combines the zero pressure differential fixation technique (by applying equal pressure to the in- and outflow ends of the valve, the aortic root is pressurized to maximize the flow area while no pressure is exerted on the leaflets) and an antimineralization treatment with alpha amino oleic acid for improved tissue durability. The device is in clinical use since February 1994. The purpose of this study was to collect intermediate term data of the Mosaic bioprosthesis in the aortic position to evaluate its clinical and hemodynamic function. From February 1994 to May 1999, 100 patients underwent aortic valve replacement with the Mosaic prosthesis at our department. There were 49 female patients, mean age at implant was 73.4 +/- 7.3 years (range 31 to 87). Concomitant procedures were done in 40%. Preoperative and operative clinical data are shown in Tables 1 and 2. When assessing the size of the bioprosthesis, it is important to use the original Mosaic sizer. Because of the possibility of the so-called supra-x placement, the specific construction of the sizer and the Mosaic valve often allow the implantation of a 1-size larger valve compared to the conventional supra-annular placement. By this a significant increase in the effective flow orifice is possible. This proceeding is depicted in Figure 1. All patients have been anticoagulated with phenprocoumon at least for 3 months postoperatively, INR was aimed at 2.5 to 3.5. Patients have been followed up prospectively, within the initial hospitalization for valve replacement, 6 months postoperatively and at annual intervals including an hematological check and transthoracic echocardiography. The mean follow-up was 2.7 years with a total follow-up of 273.7 patient years. The follow-up was 100% complete. After 5 years the mean systolic pressure gradient was 15.2 +/- 3.0 mm Hg for the 21-mm, 13.1 +/- 4.6 mm Hg for the 23-mm, 10.0 +/- 3.1 mm Hg for the 25-mm valve size, the effective orifice area 1.6 +/- 0.3 cm2 (21-mm), 1.9 +/- 0.3 cm2 (23-mm) and 2.5 +/- 0.8 cm2 (25-mm) (see Table 3). The freedom from prosthesis-related event rates, calculated according to Kaplan-Meier, at 5 years were: 97.3 +/- 1.9% for permanent neurological, 99.0 +/- 1.0% for transient neurological, 95.9 +/- 3.2% for thrombosed prosthesis, 95.6 +/- 2.2% for antithromboembolic related hemorrhage, 96.2 +/- 3.7% for structural valve deterioration, 96.9 +/- 3.0% for non-structural dysfunction, 100% for endocarditis and 92.0 +/- 4.9% for explant (see Table 4). The total operative mortality (within 30 days) was 3.0%, the late postoperative mortality was 4.4% per patient year and included a valve related mortality rate of 0.7%/patient year. In Figure 2 the survival function after aortic valve replacement is depicted, arranged in freedom from all deaths, from Mosaic-related deaths and from Mosaic-related plus sudden/unexplained deaths. Before implantation of the Mosaic bioprosthesis 95% of the patients were in NYHA Classes III and IV, whereas 6 months postoperatively 98% could be classified in NYHA Classes I and II (see Figure 3). In relation to other biological prostheses (Intact, Carpentier-Edwards Pericardial and Porcine, Hancock Modified Orifice, Biocor, Freestyle) the Mosaic bioprosthesis showed very satisfactory and predominantly better hemodynamic results than the compared stented valves and approached the performance of stentless prostheses. The freedom rates from prosthetic-related adverse events of the Mosaic bioprosthesis were at least equivalent to the compared prostheses. However, the satisfactory freedom rates, especially from structural valve deterioration, should be qualified by considering the experience that most incidences appear from the 5th year on after implantation. The clinical and hemodynamic performance of the Mosaic prosthesis has been very satisfactory during the first 5 years after clinical introduction. Further data will be necessary to confirm long-term durability.

End of the millenium--end of the single thoracic artery graft? Two thoracic arteries--standard for the next millenium? Early clinical results and analysis of risk factors in 1,487 patients with bilateral internal thoracic artery grafts.

PURPOSE: CABG with bilateral IMA grafts (BIMA) can improve long-term results in cardiac morbidity and mortality. An enhanced incidence of bleeding and wound complications compared to patients with single IMA (SIMA) remains a matter of debate. The aim of the study was to compare the operative outcomes of patients who had undergone CABG with BIMA and SIMA in situ grafts, especially to identify patient-related risk factors, such as obesity, diabetes mellitus and age above 70 years. METHODS: Out of a total of 5,144 patients operated on between January 1996 and September 1999, patients with isolated CABG (n = 3,671) with BIMA or SIMA were analyzed retrospectively. In the BIMA group, the patients' (n = 1,487) mean age was 64.0 years; mean EF was 62.1%. In the SIMA group (n = 2,184), the mean age was 65.4 years and mean EF 60.6% (n. s.). In the BIMA group, the right IMA was anterior of the aorta to the LAD, the left IMA to the lateral wall. In the SIMA group, the LAD was revascularisized with the left IMA. Additional bypasses were performed with vein grafts. RESULTS: The 30-day lethality was 1.6% in the BIMA group, 1.7% in the SIMA group in patients under 70, and 4.1% (BIMA) and 4.0% (SIMA) in patients over 70 (p = n.s.). A significantly higher blood loss was observed in the BIMA group (BIMA 979+/-708 ml, SIMA 790+/-575 ml, p<0.05). The rethoracotomy rate due to bleeding was significantly higher in patients with BIMA (4.1%) compared to those with SIMA (2.5%, p<0.05). In patients with a body mass index (BMI) of less than 27, no significant difference could be found (SIMA 2.8%, BIMA 3.4%, p = n. s.). Patients with a BMI >27 showed a significantly higher rethoracotomy rate (SIMA 2.2%, BIMA 4.9%). A higher incidence of sternal instabilities could be observed in the BIMA group (4.2%, p<0.05). Diabetes mellitus could not be identified as an independent risk factor for sternal complications (SIMA 2.9%, BIMA 5.0%, p = n. s.). COUCLUSION: CABG using both IMA's can be performed in nearly all patients as a routine method with good clinical results and low mortality. Bleeding in the BIMA group within 48 hours was increased. BMI >27 could be identified as a risk factor for sternal complications, but not diabetes mellitus or age over 70 years.

Cardiac surgery in patients with previous carcinoma of the breast and mediastinal irradiation: is the internal thoracic artery graft obsolete?

BACKGROUND: The increasing number of patients of more advanced age undergoing cardiac surgery means the number of those with previous curative (relapse free) mastectomy and irradiation of the chest is also increasing. A higher incidence of postoperative complications such as sternal infection in these patients is considered possible. Furthermore the question of whether mediastinal irradiation leads to a relevant internal thoracic artery (ITA) gaft damage remains unclear. In this context the benefit of arterial revascularization (CABG) using one or both ITAs is not sufficiently proven by data available from clinical studies. METHOD: 70 patients (49-85 years) with previous mastectomy or Hodgkin/non-Hodgkin's disease and mediastinal irradiation underwent CABG (n = 59) or an aortic valve replacement (AVR, n = 11). 20 patients received bilateral internal thoracic artery grafts, 34 a single internal thoracic artery graft, and in 16 patients an internal thoracic artery was not used. Perioperative data and data concerning postoperative complications such as mortality, myocardial infarction, and sternal infection or refixation was gathered and compared with all other patients receiving CABG (n = 5102). An histological investigation of ITA segments was done in 12 patients. RESULTS: There was no significant enhancement of the perioperative risk in comparison with other patients of a corresponding age group. Internal thoracic artery damage induced by irradiation was not present. There was no increased incidence of sternal instability requiring refixation observed. CONCLUSION: In the patient cohort investigated there is in general no need for restrictive use of the ITA in CABG.

Statistical-uncertainty-based adaptive filtering of lidar signals.

An adaptive filter signal processing technique is developed to overcome the problem of Raman lidar water-vapor mixing ratio (the ratio of the water-vapor density to the dry-air density) with a highly variable statistical uncertainty that increases with decreasing photomultiplier-tube signal strength and masks the true desired water-vapor structure. The technique, applied to horizontal scans, assumes only statistical horizontal homogeneity. The result is a variable spatial resolution water-vapor signal with a constant variance out to a range limit set by a specified signal-to-noise ratio. The technique was applied to Raman water-vapor lidar data obtained at a coastal pier site together with in situ instruments located 320 m from the lidar. The micrometeorological humidity data were used to calibrate the ratio of the lidar gains of the H(2)O and the N(2) photomultiplier tubes and set the water-vapor mixing ratio variance for the adaptive filter. For the coastal experiment the effective limit of the lidar range was found to be approximately 200 m for a maximum noise-to-signal variance ratio of 0.1 with the implemented data-reduction procedure. The technique can be adapted to off-horizontal scans with a small reduction in the constraints and is also applicable to other remote-sensing devices that exhibit the same inherent range-dependent signal-to-noise ratio problem.

Development of a scanning, solar-blind, water Raman lidar.

The need for an instrument capable of measuring water-vapor fluxes over mixed canopy and large areas has long been recognized. Such a device would greatly enhance the study of evapotranspiration processes and has great practical value for water management. To address this problem, a scanning water Raman lidar has been designed and constructed. Analytical methods have also been developed to take advantage of the type of information that this lidar can generate. The lidar is able to measure the absolute water content and calculate the evaporative flux quickly over relatively large areas. This capability provides new opportunities for the study of microscale atmospheric processes. The variogram data indicate that the spatial sampling size must be of the order of 10 m if fluxes and scalars are to be properly represented. Examples of data are presented.