Point-of-care controls for nosocomial legionellosis combined with chlorine dioxide potable water decontamination: a two-year survey at a Welsh teaching hospital.

This study reports a two-year programme of attempted eradication of Legionella colonization in the potable water supply of a 1000-bed tertiary care teaching hospital in Wales. There was a simultaneous, point-of-care, sterile-water-only policy for all intensive care units (ICU) and bone marrow and renal transplant units in order to prevent acquisition of nosocomial Legionnaires' disease. The programme was initiated following a case of nosocomial pneumonia caused by Legionella pneumophila serogroup 1-Bellingham-like genotype A on the cardiac ICU. The case occurred 14 days after mitral and aortic valve replacement surgery. Clinical and epidemiological investigations implicated aspiration of hospital potable water as the mechanism of infection. Despite interventions with chlorine dioxide costing over 25000 UK pounds per annum, Legionella has remained persistently present in significant numbers (up to 20000 colony forming units/L) and with little reduction in the number of positive sites. Two further cases of nosocomial disease occurred over the following two-year period; in one case, aspiration of tap water was implicated again, and in the other case, instillation of contaminated water into the right main bronchus via a misplaced nasogastric tube was implicated. These cases arose because of inadvertent non-compliance with the sterile-water-only policy in high-risk locations. Enhanced clinical surveillance over the same two-year period detected no other cases of nosocomial disease. This study suggests that attempts at eradication of Legionella spp. from complex water systems may not be a cost-effective measure for prevention of nosocomial infections, and to the best of our knowledge is the first study from the UK to suggest that the introduction of a sterile-water-only policy for ICUs and other high-risk units may be a more cost-effective approach.

Infective endocarditis in Europe: lessons from the Euro heart survey.

OBJECTIVES: To describe the characteristics, treatment, and outcomes of active infective endocarditis (IE) in Europe. DESIGN: Prospective survey of medical practices in Europe. SETTING: 92 centres from 25 countries. PATIENTS: The EHS (Euro heart survey) on valvar heart disease (VHD) enrolled 5001 adult patients between April and July 2001. Of those, 159 had active IE. RESULTS: 118 patients (74%) had native IE and 41 (26%) had prosthetic IE. Mean (SD) age was 57 (16) years. Blood cultures were obtained for 113 patients (71%) before antibiotic treatment was started. Surgery was performed in 52% of patients. Reasons for surgery were heart failure in 60%, persistent sepsis in 40%, vegetation size in 48%, or embolism in 18%. Surgery was for implantation of mechanical prosthesis in 63%, bioprosthesis in 21%, aortic homograft in 5%, and valve repair in 11%. In-hospital mortality was 12.6%, being 10.4% in the medical group and 15.6% in the surgical group. Among the total population of 5001 patients, only 50% of those with native VHD had been educated on endocarditis prophylaxis and only 33% regularly attended dental follow up. Of patients with IE who had had a procedure at risk during the preceding year only 50% had received adequate prophylaxis. CONCLUSIONS: The EHS on VHD shows that patients with active IE have a high risk profile and often undergo surgery. However, there are deficiencies in obtaining blood cultures and applying prophylaxis. Mortality remains high, which is a justification for the improvement of patient management through education and the implementation of guidelines.

Changes in cerebral oxygenation during cold (28 degrees C) and warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat) in patients undergoing coronary artery bypass graft surgery.

BACKGROUND: Impaired cerebral oxygenation, which is reflected by measuring jugular bulb oxygenation, is thought to play an important role in the development of neurological injury after cardiac operations with cardiopulmonary bypass (CPB). The effects of cardiopulmonary temperature and blood gas strategy on cerebral oxygenation are not fully appreciated. METHODS: Sixty patients were randomly allocated into four equal groups (cold alpha-stat, cold pH-stat, warm alpha-stat and warm pH-stat) to compare the effect of these perfusion strategies on cerebral oxygenation monitored by jugular bulb oximetry [jugular bulb oxygen saturation (SjO(2)) and arterial-jugular bulb oxygen content difference (AjDO(2))]. Jugular bulb oxygen saturation and AjDO(2) were measured before CPB, after 5, 20, 40 min on CPB, at start and end of rewarming, 5 min before the end of CPB and 10 min after CPB. Two-way analysis of variance was used to model the lowest SjO(2) and highest AjDO(2) during CPB, with CPB temperature and blood gas management as contributing factors. RESULTS: Significant changes in SjO(2) were only related to the type of blood gas management, with no significant difference between warm and cold CPB patients. In addition, during rewarming, desaturation (SjO(2)

Prevalence and clinical significance of incidental paraprosthetic valvar regurgitation: a prospective study using transoesophageal echocardiography.

OBJECTIVE: To assess the prevalence, mechanisms, and significance of paraprosthetic regurgitation detected incidentally by transoesophageal echocardiography (TOE) in patients after heart valve replacement. DESIGN: Prospective observational study. SETTING: Tertiary referral centre. PATIENTS: 360 consecutive patients (mean (SD) age 65.8(9.5) years, 193 women) undergoing elective first ever valve replacement. METHODS: Postoperative and follow up TOE, and tests for haemolysis and anaemia. RESULTS: There were 243 aortic, 90 mitral, and 27 double valve replacements, using 316 mechanical and 44 tissue valves, giving 270 aortic and 117 mitral valves. One patient with severe paraprosthetic mitral regurgitation underwent immediate reoperation and was excluded from subsequent analyses. Paraprosthetic jets were detected around 16 (6%) of the aortic and 38 (32%) of the mitral valves (p < 0.05) at the postoperative study. Follow up TOE was available for 151 aortic and 67 mitral valves, 0.9 (0.5) years after operation. Paraprosthetic jets were present in 15 (10%) of the aortic and 10 (15%) of the mitral valves (NS). Two thirds of the aortic and a fifth of the mitral jets were new. Paraprosthetic jets were more common in aortic valves in a supra-annular (12 of 88, 14%) than in an intra-annular position (4 or 182, 2%; p < 0.005) and in mitral valves inserted with continuous (36 of 88, 41%) rather than interrupted sutures (2 of 28, 7%; p < 0.001). Lactate dehydrogenase concentration was higher in patients with paraprosthetic jets than in those without (752 (236) v 654 (208) IU/l, p < 0.001). Haemoglobin and haptoglobin concentrations were not different. CONCLUSIONS: Small paraprosthetic leaks are common, are related to surgical factors, are not associated with increased subclinical haemolysis, and are benign during the first year after heart valve replacement.

Incidence of embolism and paravalvar leak after St Jude Silzone valve implantation: experience from the Cardiff Embolic Risk Factor Study.

BACKGROUND: Silver coating of the sewing ring (Silzone) was introduced as a modification of the St Jude Medical standard valve to provide antibacterial protection, but the valve has recently been withdrawn. OBJECTIVE: To study patients with these prostheses to assess possible adverse effects, and to guide their follow up. DESIGN: Prospective observational study of risk factors for stroke after valve replacement. SETTING: Cardiology and cardiac surgery departments in a tertiary centre. PATIENTS: There were 51 patients with Silzone and 116 with St Jude Medical standard valves. Patients undergoing aortic valve replacement were well matched for stroke risk factors. Silzone patients with mitral valve replacement were younger (mean (SD) age 61 (10) v 66 (7) years), more likely to be female (95% v 65%), and had more pulmonary arterial hypertension (100% v 78%), but fewer coronary artery bypass grafts (5% v 33%) than patients with standard mitral valve replacements (all p < 0.05). RESULTS: Follow up was 100% in the Silzone group (mean duration 3.0 (0.9) years) and 97.4% in the standard group (4.7 (1.4) years). Survival, morbidity, and anticoagulant control were documented over 682 follow up years (153 for Silzone and 529 for standard). There were six embolic strokes and one peripheral embolism in the Silzone group, all within three months after operation, and five embolic strokes and one peripheral embolism in the standard group. Freedom from major thromboembolism at three months was 65% in the Silzone mitral valve replacement group and 100% in the standard mitral valve replacement group (difference 35%, 95% confidence interval 8% to 62%). There was one reoperation for paravalvar leak in the standard group, but none in the Silzone group (NS). Anticoagulant control in the two groups was similar. CONCLUSIONS: Patients with Silzone mitral valves had a high rate of early postoperative embolism but no excess paravalvar leak.

Case report: Squamous carcinoma in an oesophageal foregut cyst.

Cysts within the oesophageal wall may represent inclusion cysts, retention cysts or developmental cysts. Foregut duplications are developmental anomalies, which occur as a result of abnormal canalization of the foregut during intrauterine life. Malignant transformation is an extremely rare event occurring within oesophageal cysts, adenocarcinoma being the most common histology. We report a case of squamous cell carcinoma arising within an oesophageal cyst affecting the upper third of the oesophagus. The malignant cyst was not amenable to primary surgical resection and hence was treated using chemo-radiotherapy. The treatment gave good disease control, at the expense of a high oesophageal stricture. Chemo-radiotherapy is an alternative treatment modality to achieve long-term disease control in squamous cell carcinoma complicating oesophageal foregut cyst when primary surgical resection is not possible.

Changes in serum S100beta protein and Mini-Mental State Examination after cold (28 degrees C) and warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat).

BACKGROUND: The effect of cardiopulmonary bypass temperature and blood gas management on the brain is still controversial. This study was designed to compare the changes in S100beta protein concentration and Mini-Mental State Examination in patients undergoing cold (28 degrees C) vs. warm (34 degrees C) cardiopulmonary bypass using different blood gas strategies (alpha-stat and pH-stat). METHODS: Sixty patients were randomly allocated to one of four equal groups (cold alpha-stat, cold pH-stat, warm alpha-stat, warm pH-stat). Serum S100beta concentrations were measured before CPB, directly after CPB, at 4.5 h and at 24 h after CPB. Mini-Mental State Examination was performed one day before surgery and on day five after the operation. Antegrade warm blood cardioplegia (37 degrees C) was used in all patients. RESULTS: There was no significant difference in postoperative S100beta protein levels between the four groups. Also, there was no interaction between bypass temperature and type of blood gas strategy on S100beta levels after bypass (directly after bypass, 4.5 h and 24 h after bypass). Mini-Mental State Examination score was not affected by blood gas strategy but it was significantly lower in patients undergoing cold cardiopulmonary bypass surgery: median (range), 26 (12-29) vs. 27 (23-30) in warm patients, P = 0.014. There was no significant correlation between Mini-Mental State Examination score 5 days after CPB and S100beta levels at any of the studied time-points after CPB. CONCLUSION: These results support the use of warm CPB (34 degrees C) in patients undergoing coronary artery bypass surgery regardless of the type of blood gas strategy.

Prospective study of routine perioperative transesophageal echocardiography for elective valve replacement: clinical impact and cost-saving implications.

Transesophageal echocardiography (TEE) is widely used during heart valve replacement operations, but its clinical impact and cost-saving profile have not been studied prospectively for this indication. We investigated the clinical benefits and cost-savings of routine TEE for elective valve replacement at a regional tertiary center. We prospectively studied 300 patients (140 men; mean age [+/-SD], 66 +/- 9 years) undergoing aortic valve, mitral valve, or double-valve replacements. Transesophageal echocardiography with a biplane (in 161 patients) or a multiplane probe was performed before and after surgery. We assessed whether the TEE findings changed the operation or the postoperative treatment and the cost of TEE either as an extension of a preexisting service or as a new development. In 2 patients undergoing aortic valve replacement, significant mitral regurgitation on TEE led to additional mitral valve replacement, and in 1 patient undergoing mitral valve replacement, aortic regurgitation also required aortic valve replacement. Immediate reoperation (dehisced mitral valve prosthesis) and delayed extubation (suspected obstruction of an aortic valve prosthesis) were prompted by postoperative TEE. Extending an existing TEE service to routine intraoperative use saved up to $109 (US) per patient per year. Routine intraoperative TEE can provide major clinical benefit to a small proportion of patients undergoing elective valve replacement, and this can lead to cost savings, but only if the service can be provided without major capital investment.

Twenty years' experience with the Medtronic Hall valve.

OBJECTIVE: To assess the performance of the Medtronic Hall valve (Medtronic, Inc, Minneapolis, Minn) in one institution over a 20-year period. METHODS: Since 1979, Medtronic Hall valves have been used in 1766 procedures (736 aortic, 796 mitral, and 234 double). Patients were followed up prospectively at 6- to 12-month intervals for a total of 12,688 follow-up years. Anticoagulation data (international normalized ratio) were recorded for all patients (approximately 95,000 observations). RESULTS: Linearized rates of valve-related late death for aortic, mitral, and double valve replacement were 0.8%/y, 0.9%/y, and 1.1%/y, respectively. Risk factors for late mortality were (relative risk) diabetes (1.9), decade of age (1.6), concomitant coronary artery bypass grafting (1.4), hypertension (1.3), non-sinus rhythm (1.3), large valve size (1.1), valve regurgitation (1.3), and male sex (1.2). For aortic, mitral, and double valve replacement, linearized rates (percent per year) of adverse events were valve thrombosis 0.04, 0.03, and 0.0; all thromboembolism 2.3, 4.0, and 3.4; stroke 0.6, 0.8, and 0.6; major hemorrhage 1.2, 1.4, and 1.6; and prosthetic endocarditis 0.4, 0.4, and 0.7. Risk factors for thromboembolism were (relative risk) mitral valve replacement (1.9), diabetes (1.8), hypertension (1.5), and history of embolism (1.4). CONCLUSION: At 20 years the Medtronic Hall valve demonstrates excellent durability, good hemodynamic performance, and very low thrombogenicity, with a valve thrombosis rate lower than those reported for bileaflet designs. With this prosthesis, both survival and thromboembolic events are predominantly determined by patient risk factors.

Morphologic analysis of a strand recovered from a prosthetic mitral valve: No evidence of fibrin.

We report the first morphologic analysis of a linear mobile structure (strand) detected by transesophageal echocardiography on a bioprosthetic mitral valve and then recovered at surgery. Electron microscopy showed it to consist of a sparsely cellular component, with extracellular amorphous or fibrillary areas. Collagen was largely responsible for the fibrillary appearance.

A new strategy of total arterial revascularization.

We report a new strategy of total arterial revascularization based on bilateral internal thoracic arteries (ITAs) and a radial artery (RA). The technique employs a graft extension of the proximal third of the right internal thoracic artery (RITA) with the RA, in combination with the T-graft technique, by which the lower two-thirds of the free RITA is anastomosed to the side of the left internal thoracic artery (LITA).

Contemporary management of malignant pleural mesothelioma.

The rapidly increasing incidence of malignant pleural mesothelioma underlines the urgency to achieve a consensus in the management of this tumor, which is biologically distinct from most other tumors. For patients with stage I tumors of epithelial type and good performance status, pleuropneumonectomy combined with chemotherapy and radiotherapy provides the best chance of prolonged survival, but further investigation is required to determine the optimum combination of adjuvant therapy. Debulking pleurectomy/decortication combined with adjuvant therapy is a worthwhile alternative for patients with more advanced disease, impaired performance status or tumors of less favorable histology (sarcomatous or biphasic). More clinical trials are urgently required to identify better adjuvant therapy for tumors containing sarcomatous elements. On currently available evidence, neither radiotherapy nor chemotherapy offer worthwhile prolonged disease control when used in isolation, although both have an important role as part of multimodality therapy. Hyperthermia may enhance the effect of both radiotherapy and chemotherapy, and newer radiosensitizing agents also need evaluating. Research into immunotherapy and gene therapy suggests that these newer approaches may have a place if tumor volume is small. In practice they will probably need to be combined with other therapeutic modalities, and further clinical trials are required. Consensus in mesothelioma management currently remains elusive but it seems clear that the way forward will involve striving for much earlier diagnosis, the use of multimodality therapy and collaboration between centers with special expertise in mesothelioma treatment to organize multicenter trials.

Therapeutic options in malignant mesothelioma.

No significant advances have been made in the treatment of diffuse malignant mesothelioma in the past 12 months. For fit patients with early disease (stage I), radical surgery remains the best option, but doubt remains concerning optimum adjuvant therapy. A collaborative approach with multicentre trials of standardized treatment protocols is essential if any progress is to be made in the future.

Arterial risk factors and ischemic cerebrovascular events after aortic valve replacement.

To assess the association of possible risk factors with ischemic cerebrovascular events after aortic valve replacement (AVR), 619 consecutive patients undergoing AVR with a Medtronic Hall valve between the beginning of December 1979 and the end of December 1992 and surviving the immediate postoperative period were analyzed. Possible risk factors examined were valve lesion, prosthesis size, postoperative functional status, systemic hypertension, cigarette smoking, diabetes, coronary artery disease and atrial fibrillation. There were 53 ischemic cerebrovascular events in 38 patients during 3,174 follow up years, yielding a linearized event rate of 1.7%/patient-year. Significant risk factors in terms of odds ratios (OR) were postoperative hypertension (OR 8.0), postoperative NYHA class III or IV (OR 5.5), postoperative smoking (OR 4.0), diabetes (OR 3.5), preoperative hypertension (OR 2.7) and preoperative smoking (OR 1.8). There was highly significant interaction between postoperative hypertension and postoperative smoking (OR 54.0). Eighty-one percent of patients who suffered events were hypertensive or smoking postoperatively or both. These findings have important implications for postoperative management and for the reporting of ischemic cerebrovascular events after valve replacement.

Preoperative staging of carcinoma of the bronchus: can computed tomographic scanning reliably identify stage III tumours?

BACKGROUND: The aim of preoperative computed tomographic (CT) assessment of patients with carcinoma of the bronchus is to stage the tumour accurately, and forewarn the surgeon of any possible local extrapulmonary extension of tumour in patients considered to have potentially resectable disease. The ability of CT scanning to differentiate between conventionally resectable lung cancer (TNM stages I and II), locally advanced but resectable lung cancer (TNM stage IIIa), and locally advanced but unresectable lung cancer (TNM stage IIIb) was determined in a group of patients accepted for surgery. METHODS: Computed tomographic scans of 110 patients who underwent thoracotomy for intended resection of carcinoma of the bronchus, including 52 cases with stage III and 58 cases with stage I or II disease, were reviewed and the CT features and radiological interpretations correlated with the surgical and pathological findings. RESULTS: Thirteen CT scans were judged not to have been of diagnostic quality: of the remaining 97 cases 45 had stage III lung cancer, of whom 30 had successful resections, and 52 had stage I or stage II tumours. There was no difference in the frequencies of CT observations--including contiguity of tumour and mediastinum or chest wall, apparent mediastinal or chest wall invasion, proximity of tumour to the carina, mediastinal nodal enlargement, pulmonary collapse or consolidation and pleural effusion--in patients with stage I/II disease and patients with stage III disease. Similar results were found when the same observations were compared in all patients with resected disease and those with unresectable tumour. Sensitivity and specificity of CT was 27% and 96% respectively for tumour unresectability, 50% and 89% for mediastinal invasion, 14% and 99% for chest wall invasion, and 61% and 76% for mediastinal nodal metastases. Only 19 of 45 stage III tumours were correctly identified as being stage III and resectable or unresectable. CONCLUSIONS: In patients being considered for thoracotomy for resection of lung cancer, CT scanning used as the sole method of staging is of limited value for differentiating between stage I/II and stage III tumours. Patients should not be denied the opportunity for curative surgery on the basis of equivocal CT signs.

The role of risk factors and trigger factors in cerebrovascular events after mitral valve replacement: implications for antithrombotic management.

To determine the effect of risk factors and trigger factors on cerebrovascular events, 622 patients who survived mitral valve replacement between December 1979 and December 1992 were analyzed. Ninety-six patients suffered 139 nonhemorrhagic cerebrovascular events. Data were available on 138 events in 95 patients. There were 32 transient ischemic attacks (TIAs), 57 reversible ischemic neurological deficits (RINDs), and 49 strokes. Age, sex, atrial fibrillation, left atrial size, systemic hypertension, and abnormal body mass index did not discriminate between patients who suffered events and those who did not. In contrast, smoking status differed significantly between patients who suffered events and those who did not. Among current or recent ex-smokers, the risk of stroke or RIND was significantly higher than in non-smokers (p < < 0.001). The odds ratio of suffering any type of event in patients who smoked at any time postoperatively versus those who did not smoke was 2.9 (95% confidence interval: 1.8 to 4.6). Of 61 patients contacted directly, 30% recalled an infective episode immediately prior to their event. A diurnal and seasonal influence on events was also detected with peaks in the morning and in the winter months, respectively (both p < 0.001). It is concluded that there is persuasive evidence for the involvement of several nonprosthetic factors in the incidence of cerebrovascular events after mitral valve replacement. This has implications for patient management and for future analysis of prosthetic heart valve series.

Computed tomographic assessment of patients following radical surgery for malignant mesothelioma.

Serial computed tomographic (CT) scans of the thorax and upper abdomen were performed in eight patients following radical surgery (pleuro-pneumonectomy) for diffuse malignant mesothelioma of the pleura. The post-operative appearances included a well defined membrane lining the pleuro-pneumonectomy space in seven cases; in two cases this resembled the original tumour. In six patients there was upward abdominal visceral displacement on the side of the surgery due to diaphragmatic resection; this resulted in contralateral mediastinal shift in four patients. One patient required a diaphragmatic prosthesis which produced a distinctive CT appearance. CT suggested recurrent mesothelioma in five cases. Although two patients had evidence of intrathoracic recurrence, in three patients the only feature was the non-specific finding of abdominal ascites. The normal CT appearances after pleuro-pneumonectomy should be recognized to facilitate radiological interpretation. With careful application CT is of value for the assessment of recurrent disease in patients following radical surgery for malignant mesothelioma.

Neurilemmoma of the intrathoracic vagus nerve.

A neurilemmoma (Schwannoma) of the left intrathoracic vagus nerve was discovered on a chest radiograph of a 28 yr old woman and was removed via a left thoracotomy. Although neurogenic tumours are the most common tumours of the mediastinum, they rarely involve the intrathoracic vagus nerve.