An open-source high-frequency lock-in amplifier.

We present characterization of a lock-in amplifier based on a field programmable gate array capable of demodulation at up to 50 MHz. The system exhibits 90 nV/√Hz of input noise at an optimum demodulation frequency of 500 kHz. The passband has a full-width half-maximum of 2.6 kHz for modulation frequencies above 100 kHz. Our code is open source and operates on a commercially available platform.

Massive right atrial myxoma causing exertional dyspnoea.

Metastatic tumours are the commonest cardiac tumours being found in 1-3% of patients dying of cancer while primary tumours are unusual and have an incidence of 0.02-0.5%. The majority (80%) of all primary cardiac tumours are benign with myxomas accounting for 50%. Myxomas arising from the right atrium are uncommon. We present the case of a 39-year-old female with a 4-month history of progressive exertional dyspnoea accompanied by symptoms of palpitations and presyncope. Transthoracic echocardiography showed an extremely large right atrial myxoma prolapsing into the right ventricle and obstructing the tricuspid valve. We demonstrate how intraoperative transoesophageal echocardiography, prior to sternotomy, was useful in providing information about the myxoma which clearly displayed its attachment and anatomical relationship in the planning of the 'safe' surgical excision.

Axillary and tympanic membrane temperature measurements are unreliable early after cardiopulmonary bypass.

BACKGROUND AND OBJECTIVE: Inaccurate measurements of body temperature following cardiopulmonary bypass may be associated with serious complications. The purpose of this study was to determine whether axillary and tympanic temperature measurements correlate with the urinary bladder temperature in the early postcardiac surgery period. METHODS: Forty-nine adult patients who underwent cardiac surgery under cardiopulmonary bypass at our institution were prospectively studied. Urinary bladder, right axillary, right tympanic and left tympanic temperature measurements were simultaneously recorded at 0, 6, 12 and 18 h following cardiopulmonary bypass. Patients had one to four sets of recordings and a total of 629 temperature measurements were recorded. The mean difference (bias) between the bladder and each of the other methods and limits of agreement were calculated using Bland and Altman method. RESULTS: The mean core body temperature recorded from the bladder on admission to the intensive care unit was 36.4 degrees C. After 6, 12 and 18 h the mean core body temperature was 37.4 degrees C (range: 35.2-39.0), 37.5 degrees C and 37.45 degrees C, respectively. The mean differences (bias) between the bladder temperature and the other three methods were: left tympanic, 0.65 degrees C (95% CI: -0.24 to 1.58); right tympanic, 0.57 degrees C (95% CI: -0.48 to 1.63) and right axillary, 0.55 degrees C (95% CI: -0.27 to 1.36). CONCLUSIONS: The axilla and tympanic membrane are unreliable sites for core body temperature measurement early after cardiopulmonary bypass in adult patients and clinical decisions should be based on more reliable methods.

Can we rely on arterial line sampling in performing activated plasma thromboplastin time after cardiac surgery?

BACKGROUND AND OBJECTIVE: Arterial catheters are routinely used to sample blood for clotting studies in most cardiothoracic intensive care units. The clotting profile in surgical bleeding after cardiac surgery influences further management. Aspiration and discard of a certain amount of blood from the line, prior to sampling, are assumed to clear heparin contamination. We have investigated this assumption through analysis of the clotting profile by simultaneous arterial line and peripheral venous samples. METHODS: The morning following cardiac surgery, simultaneous arterial line and peripheral venous blood samples were taken for activated plasma thromboplastin time (APTT) ratio and international normalized ratio (INR) in 49 randomly selected patients. Also, a thromboelastogram analysis (TEG) (n = 7) was made. A survey of 22 UK cardiothoracic intensive care units was carried out to determine the practice for the withdrawal of blood for clotting studies. RESULTS: The median arterial APTT ratio value was 1.32 +/- 0.52 as compared to the median peripheral APTT ratio value which was 1.1 +/- 0.24 (P < 0.001). INR values were statistically similar by both routes. Heparin contamination was confirmed by TEG which revealed that the R-value for arterial catheter blood samples without heparinase in the cup was higher (406.00 +/- 64.44 s) compared with the value for arterial samples with heparinase in the cup (318.28 +/- 47.26s, P < 0.05). The survey of 22 UK cardiothoracic intensive care units showed that heparinized arterial lines were by far the commonest ports used for blood withdrawal for the measurement of APTT ratio results. CONCLUSIONS: Samples withdrawn from heparinized arterial lines cannot be relied upon for APTT ratio results.

Issues concerning consent in patients undergoing cardiac surgery-the need for patient-directed improvements: a UK perspective.

AIMS: To determine the extent to which informed patient consent for cardiac surgery corresponds with standard guidelines and to assess patient satisfaction with the consent process. METHODS: A questionnaire developed in accordance with consent guidelines published by the Medical Defence Union (MDU) and the Practicalities Of Producing Patient information (POPPi) Guide was administered to 82 patients after they were consented for cardiac surgery. RESULTS: Patients were informed about i) type of operation [n=80, 97.5%] ii) reason for surgery [n=78, 95%] iii) surgical procedure [n=77, 94%] iv) length of hospital stay [n=73, 89%] and v) post-surgical care [n=79, 96.3%]. However, a decreasing number of patients were notified about i) possible risks of surgery [n=64, 78%] and ii) consequences of no surgery [n=62, 75.6%]. Interestingly, patients received less adequate information about i) alternative methods of treatment (n=34, 41.4%], ii) future lifestyle (n=55, 67%] and iii) medications following surgery [n=40, 48.7%]. 81% (n=67) were overall 'satisfied' with the information provided. More than 95% (n=78) patients were invited to ask questions. The most commonly asked questions were about i) quality of life ii) length of operation and hospital stay iii) surgical procedure iv) consequences of no surgery. CONCLUSIONS: The study has highlighted areas of informed consent in cardiac surgical patients that need attention. Although, patients were generally satisfied and well informed about the procedure, less information was presented covering alternative treatments, future lifestyle and medications. This was reflected in the questions asked by patients and their suggested improvements for the consent procedure.

A prospective study of changes in the quality of life of patients following mitral valve repair and replacement.

OBJECTIVE: The primary aim of medical care and surgery for mitral valve disease is to improve the overall functional capacity and health of patients. AIM: To assess whether there was an actual improvement in quality of life (QOL) of patients 3 months following primary mitral valve repair (MRr) or mitral valve replacement (MVR). METHODS: Prospective study of 61 consecutive patients (34 males, mean age 64+/-12) who underwent primary, isolated mitral valve repair (MRr, n=40) or mitral valve replacement (MVR, n = 21) from April 1997 to October 1998. QOL parameters using the validated short form 36 (SF-36) questionnaire were determined before and at 3 months after surgery and analysed using the Wilcoxon matched pairs rank test. RESULTS: Mean QOL scores (scale 0-100) for all patients following mitral valve surgery showed clinical and statistically significant improvement in seven of eight QOL parameters, namely (i) physical function (post, 60+/-31 vs. pre, 44+/-29; P = 0.0001); (ii) role limitation due to physical function (50+/-42 vs. 23+/-36; P = 0.0002); (iii) social function (76+/-31 vs. 59+/-36; P = 0.0006); (iv) role limitation due to emotional problems (65+/-42 vs. 44+/-45; P = 0.003); (v) energy (57+/-24 vs. 40+/-24; P < 0.0001); (vi) mental health (73+/-20 vs. 66+/-21; P = 0.007); and (vii) general health perception (68+/-19 v 56+/-22; P = 0.0001); but not pain (73+/-29 v 71+/-30; P = 0.4). Following MRr there was significant improvement in seven of eight QOL parameters and following MVR there was significant improvement in three of eight QOL parameters. Whilst patients with ejection fraction > or = 50% showed significant improvement in seven of eight QOL parameters, there was no significant improvement in any QOL parameters in patients with impaired left ventricular (LV) function. Similarly, patients with mitral regurgitation with end-systolic dimensions of > or = 45 mm showed no significant improvement in any QOL parameters at 3 months follow-up. CONCLUSIONS: Our study suggests that following mitral valve surgery there was significant improvement in the QOL of patients especially in those patients requiring mitral valve repair. However, patients with impaired LV function and those with MR with end-systolic dimensions > or = 45 mm were unlikely to demonstrate a significant improvement in QOL at 3 months follow-up.

A prospective study of changes in patients' quality of life after aortic valve replacement.

BACKGROUND AND AIM OF THE STUDY: After aortic valve replacement (AVR), 90% of survivors are in NYHA class I or II, and most return to work after three months. It is unclear, however, whether at that time patients have an improved quality of life (QOL), are able to perform physical and social activities, and live independently. METHODS: To assess this situation, 62 patients (39 males, 23 females; mean age 68.5 +/- 10 years) who underwent primary AVR completed the validated Short Form 36 (SF-36) questionnaire. QOL parameters were determined before and three months after surgery prospectively, and analyzed using the Wilcoxon matched pairs rank test. RESULTS: All patients showed significant improvement in all eight QOL parameters (score 0-100): (i) physical function (67 +/- 26 versus 37 +/- 28; p <0.00001); (ii) role limitation due to physical function (52 +/- 43 versus 20 +/- 37; p <0.0001); (iii) social function (80 +/- 25 versus 59 +/- 30; p <0.0001); (iv) role limitation due to emotional problems (64 +/- 41 versus 41 +/- 46; p = 0.01); (v) energy (62 +/- 22 versus 42 +/- 23; p <0.00001); (vi) mental health (78 +/- 19 versus 63 +/- 22; p <0.00001); (vii) pain (78 +/- 27 versus 67 +/- 32; p = 0.02); and (viii) general health perception (72 +/- 20 versus 58 +/- 21; p <0.00001). Significant improvements in QOL parameters were: (i) after mechanical and bioprosthetic AVR, seven of eight QOL parameters were improved; (ii) patients aged < 70 years had pronounced improvement in six of seven parameters, while those aged > or = 70 years had limited improvement in five of eight parameters; (iii) patients with valve sizes 19 and 21 mm improved in five of eight parameters, while those with > or = 23 mm implants improved in all eight parameters, regardless of post-AVR peak gradient of < 20 or > or = 20 mmHg; and (iv) patients with left ventricular end-diastolic dimension (LVEDD) < 55 mm improved in all eight parameters while those with LVEDD > or = 55 mm improved in only five parameters. CONCLUSION: There was significant improvement in patients' QOL at three months after AVR, regardless of the type of aortic implant used; improvement was greatest in those aged < 70 years. The results also suggest that patients with smaller implants (who were older) and those with LVEDD > or = 55 mm were less likely to show significant improvement in all QOL parameters at three months after AVR.

Effect of aortic valve replacement on plasma soluble P-selectin, von Willebrand factor, and fibrinogen.

We measured indexes of platelet activation (soluble P-selectin), endothelial dysfunction (von Willebrand factor), and fibrinogen in 54 patients who underwent aortic valve replacement (AVR): after mechanical AVR implantation, there was a significant increase in plasma levels of soluble P-selectin and von Willebrand factor levels 3 months after surgery, with no change in mean plasma fibrinogen levels. No significant changes in measured indexes were noted in patients undergoing biologic AVR, suggesting that mechanical AVR results in abnormal endothelial damage and/or dysfunction and platelet activation, which is not apparent among patients undergoing this procedure.

Primary left atrial fibrosarcoma.

An elderly female with refractory cardiovascular symptoms due to functional mitral stenosis secondary to a primary left atrial fibrosarcoma is described. The symptoms are often nonspecific and most of the patients present first time with hemodynamic compromise. A high index of suspicion is essential for the early diagnosis of these highly malignant cardiac tumors because of their rarity, a wide spectrum of nonspecific symptoms and poor survival.

Atrial endocardial changes in mitral valve disease: a scanning electron microscopy study.

BACKGROUND: The precise contribution of left atrial appendage (LAA) endocardial damage and dysfunction to the process of thrombus formation in patients with mitral valve (MV) disease, especially in the presence of atrial fibrillation (AF), has not as yet been clearly described. This may be important because the LAA is the usual site for thrombus formation. METHODS: The purpose of this study was to describe endocardial surface changes, through the use of scanning electron microscopy, in the left and right atrial appendages of patients with MV disease and the differences, if any, between patients with mitral stenosis and mitral regurgitation as well as between those with AF and sinus rhythm. Our second objective was to relate endocardial changes to plasma levels of von Willebrand factor (vWf), an established marker for endothelial damage. LAA specimens were obtained immediately after commencement of cardiopulmonary bypass from 35 patients (18 men; mean age 65 years, range 20 to 85) during surgery for MV repair or replacement. Right atrial appendage (RAA) specimens were similarly obtained as controls for individual patients. The specimens were fixed in 2.5% glutaraldehyde solution overnight, stored in Sorensen's phosphate buffer, and examined by means of scanning electron microscopy. Two independent observers documented the most advanced lesion in each specimen as follows: (1) "minimal" changes, with minimal disruption of the endocardium; (2) "intermediate" changes or prethrombotic lesions; and (3) "advanced" changes, with endocardial disruption and thrombotic lesions. Plasma levels of vWf were also measured (enzyme-linked immunosorbent assay) in all patients, and results were compared with those of age- and sex-matched healthy control patients. RESULTS: Advanced changes were more frequently seen in the endocardium of the LAA when compared with the RAA (31% vs 6%), whereas minimal changes were more frequently seen in the RAA compared with the LAA (23% vs 6%) (P =.00167). Similarly, the LAA from patients with mitral stenosis had a higher proportion of "advanced" endocardial changes when compared with patients with mitral regurgitation (67% vs 24%; P =.0066). The LAA in patients with AF had more "advanced" changes (39% vs 27%), but this was not statistically significant. Plasma vWf levels were significantly higher in patients with MV disease compared with healthy control patients (132 +/- 33 IU/dL vs 99 +/- 37 IU/dL; P =.0004) and in patients with advanced LAA changes compared with earlier changes (149 +/- 34 IU/dL vs 121 +/- 31 IU/dL; P =.042). CONCLUSIONS: Endocardial damage occurs in the atrial appendages of patients with MV disease. Potentially thrombogenic changes are more commonly seen in the LAA compared with the RAA and in patients with mitral stenosis compared with mitral regurgitation. These anatomic appearances may contribute to the risk of intra-atrial thrombus formation in patients with mitral valve disease, especially if AF is present.

von Willebrand factor, fibrinogen, and soluble P-selectin levels after mitral valve replacement versus mitral valve repair.

Patients with mitral valve disease undergoing surgery are at an increased risk of thromboembolism. We hypothesized that this may be due in part to abnormalities in platelet activation, endothelial damage or dysfunction, and plasma fibrinogen in such patients. To test this hypothesis, we measured indexes of platelet activation (soluble P-selectin), endothelial damage or dysfunction (von Willebrand factor [vWf], enzyme-linked immunosorbent assay) and fibrinogen (modified Clauss) in 56 consecutive patients (35 women, mean age 65 years) admitted for isolated mitral valve repair (n = 39) or replacement (using mechanical implants, n = 17). Samples were taken from a peripheral vein before and at 3 months after valve surgery. Baseline results were compared with 56 healthy age- and sex-matched controls. Compared with controls, patients with mitral valve disease had higher levels of vWf (mean +/- SD 132 +/- 28 vs 101 +/- 35 IU/dl; p <0.001), but there were no significant differences in mean fibrinogen (p = 0.418) or soluble P-selectin (p = 0.855) levels between cases and controls. There was a significant increase in plasma vWf after mitral valve replacement: 142 +/- 25 IU/dl preoperatively, increasing to 161 +/- 33 IU/dl at 3 months after surgery (p = 0.0261). However, there were no significant changes in plasma fibrinogen (p = 0.306) or soluble P-selectin levels (p = 0.191). Patients undergoing mitral valve repair did not have any significant changes in mean vWf (p = 0.25), soluble P-selectin (p = 0.77), or fibrinogen (p = 0.22). There was a significant negative correlation (Spearman, r = -0.4, p = 0.003) in postoperative plasma vWf levels and the size of valve prosthesis used. Thus, patients with mitral valve disease have increased plasma vWf levels when compared with healthy controls, suggesting endothelial damage or dysfunction, with a further increase in levels after mitral valve replacement. Conversely, patients undergoing mitral valve repair do not demonstrate any significant changes in fibrinogen, or indexes of endothelial dysfunction or platelet activation.

Hyperlipidaemia management after primary coronary artery bypass surgery: a survey of patients and general practitioners.

BACKGROUND: It is well established that, in patients with increased cholesterol concentrations and vascular disease, decreasing the cholesterol concentration significantly reduces the risk of coronary events. After coronary artery bypass graft surgery (CABG), the risk of further coronary events is likely to be reduced if there is effective control of cholesterol concentrations. The aim of the survey was to review awareness among general practitioners and patients of the need for maintenance of serum cholesterol values, frequency of serum cholesterol checks, dietary advice and lipid-decreasing medication in patients after CABG. METHODS: Hospital notes of 200 patients who underwent primary, coronary artery bypass surgery from January 1994 to 1996 were examined and postal questionnaires sent to patients and their general practitioners inquiring whether they had had their serum cholesterol tested in the past 3 years; whether dietary advice had been given if cholesterol concentrations were increased to more than 5.2 mmol/l; whether a repeat serum cholesterol test was performed 3 months later if values were greater than 5.2 mmol/l; and (for those with serum cholesterol values greater than 5.2 mmol/l), whether they were on lipid-decreasing medication. RESULTS: We considered 146 (76%) replies to be complete. Hospital and general practitioner records of these patients showed, that in the previous 3 years, after CABG, only 63% (n=92) had their serum lipid profile checked and, of these, 74% (n=68) had increased serum cholesterol concentrations of more than 5.2 mmol/l. Only 46% (n=31) received dietary advice alone. After dietary advice had been given, serum cholesterol was rechecked in 26% (n=8) of patients and only 3% (n=1) had a decrease in serum cholesterol to less than 5.2 mmol/l. Among the patients with increased serum cholesterol, 50% (n=34) received lipid-decreasing medication, but serum cholesterol was rechecked in only 52% (n=17) of patients. In 9% (n=3) of these, serum cholesterol concentrations had decreased to less than 5.2 mmol/l. Among the 146 complete replies from patients, 95% (n=139) indicated that control of serum cholesterol was important, 82% (n=120) had received dietary advice and 39% (n=57) were on lipid-decreasing medication. CONCLUSION: General practitioners and patients were generally aware of cholesterol control after CABG. However, a relatively low proportion of patients underwent serum cholesterol checks and received documented dietary advice, lipid-decreasing medication, or both. Dietary advice alone may be inadequate in controlling lipid concentrations and, in many cases, needed to be supplemented with adequate lipid-decreasing therapy.

Comparison of primary coronary artery bypass surgery in a British Indo-Asian and white Caucasian population.

AIM: To compare the clinical characteristics, at the time of admission and after coronary revascularization by bypass surgery, among British patients of Indo-Asian and white Caucasian descent. METHOD: One hundred and ninety-four pairs of patients admitted between November 1994 and January 1997 were matched for age (within 3 years), sex and date of admission (within 3 months). Their clinical characteristics at the time of admission for coronary artery bypass grafting surgery, and the incidence of hospital morbidity, hospital mortality and length of stay in the intensive therapy unit or hospital following coronary artery bypass grafting were determined. RESULTS: A higher proportion of Indo-Asian patients underwent coronary revascularization on a non-elective basis (43% vs 32% white Caucasian patients, P =0.018), had a higher prevalence of diabetes (39% vs 12%, P =0.0001), a lower prevalence of smoking (36% vs 80%, P =0.0001) and a lower rate of previous myocardial infarction (47% vs 62%, P =0.012). As regards revascularization, although there was no significant difference in the number of vessels revascularized, there was a lower use of the arterial conduit (internal mammary artery) in the Indo-Asian patients (72% vs 81%, P =0.028) particularly for those undergoing emergency/urgent surgery (59% vs 72%, P =0.001) and with a previous myocardial infarction (65% vs 81%;P =0.01) when compared with their white Caucasian counterparts. Following surgery there were no differences in the types of support required for vital functions. There was no significant difference in the proportion of major post-operative complications, that is, haemorrhage, cerebrovascular accident, renal failure requiring dialysis or respiratory failure. Similarly, there were no differences in the length of intensive therapy unit stay (median stay 1 day vs 1 day, P =0.4) and hospital stay following surgery (median stay 6 days vs 6 days, P =0.5) between the two groups. Although there was a trend towards a higher in-hospital (30 day) mortality (6.7% [95% confidence intervals CI 3.18-10.21] vs 2.6% [CI 0.35-4.9;P =0.0618]), in Indo-Asians compared to white Caucasians this trend disappeared when patients in the two groups undergoing non-elective surgery only were compared (9% vs 7%;P =0.7). CONCLUSIONS: A higher proportion of Indo-Asians underwent non-elective coronary revascularization, with a significantly lower use of the arterial conduit and a relatively higher in-hospital mortality. Following coronary revascularization the medical management, length of stay and hospital morbidity in Indo-Asian patients was no different from that of their white Caucasian counterparts. This is despite a perceived poorer outcome in Indo-Asians compared to white Caucasians.

A survey of hospital morbidity, mortality and quality of life following coronary artery bypass surgery in a UK Indo-Asian population.

To survey the in-hospital morbidity, mortality, length of stay in the intensive therapy unit (ITU) and hospital and quality of life in patients of Indo-Asian origin following coronary artery bypass (CABG) surgery, 345 consecutive patients (mean age 58 years; SD 8.9; range 32-88 years) undergoing primary, isolated CABG were studied. Non-elective CABG was undertaken in 41% of patients. The left anterior descending artery (LAD) was grafted in 89%, although in 30% of these the internal mammary artery (IMA) was not used. Following CABG, the hospital morbidity and mortality was within the expected range, although there was a trend towards higher in-hospital mortality in the Parsonnet low risk group of patients. The length of ITU and hospital stay was not prolonged. Using the SF-36 questionnaire in postoperative patients, low quality of life scores were obtained for six of the eight modalities tested including physical functioning, bodily pain and general health perception. The low quality of life scores and IMA usage in Indo-Asians needs to be addressed.

Evaluation of the Sorin bicarbon bileaflet valve in 488 patients (519 prostheses).

The Sorin bicarbon bileaflet prosthesis was introduced in 1990. To evaluate the clinical performance of this prosthesis, we reviewed 519 prostheses that were implanted in 488 patients (275 men, 213 women; mean age 59 years; SD 10.8, range 19 to 88) from 1993 to 1997. Preoperatively, 82% of patients were in New York Heart Association (NYHA) functional class III or IV. There were 263 aortic valve replacements (AVRs) (54%), 194 mitral valve replacements (MVRs) (40%), and 31 AVRs and MVRs (both) (6%). Concomitant procedures were performed in 82 patients (17%). Follow-up was complete in 471 (97%) with a total cumulative follow-up of 866 patient-years. The 30-day mortality for patients with AVR was 5.7% (95% confidence interval [CI] 2.9 to 8.5), MVR 17.5% (CI 9.9 to 19.7), and both 19% (CI 7.6 to 51.1), with no early valve-related deaths. Patient survival at 55 months was 76% (SE 2.27%), with patients with AVR being 90%, MVR 63%, and both 61%. This was influenced by the following: (1) valve position, which was higher for MVR (p = 0.0001); (2) poor NYHA functional class (p = 0.0006); (3) reoperation (p = 0.02); and (4) age >70 years (p = 0.0001). Valve-related complications (expressed as percentage per patient year and number of events) were major thromboembolism at 0.9% per year (8), with AVR rates being 1.2% per year (6) and MVR 0.7% per year (2); major hemorrhage at 2.3% per year (20) with AVR rates being 2.4% per year (12) and MVR 2.5% per year (7); bacterial endocarditis at 0.2% per year (2); and nonstructural dysfunction rate of 0.7% per year (6). The reoperation rate was 0.9% per year (8) with AVR being 0.6% per year (3) and MVR 1.7% per year (5). At 55 months, actuarial freedom from major thromboembolism was 97% (SE 1.1%) with AVR being 96% and MVR 98%; major hemorrhage 89% (SE 3.1%) with AVR being 88.6% and MVR 91%; structural valve dysfunction 100% (SE 0.0%); and reoperation 97.1% (SE 1.10%) with AVR being 98.5% and MVR 94.6%. At follow-up, 88% of survivors were in NYHA class I or II. In this series, hospital mortality and overall survival in patients were influenced by the patients' clinical characteristics. There were no early valve-related deaths. Valve-related complications were similar to previously reported series with no episode of structural failure. Our experience with the Sorin bicarbon bileaflet prosthesis suggests that it has a satisfactory clinical performance, with low complication rates.

Hospital morbidity and mortality and changes in quality of life following mitral valve surgery in the elderly.

BACKGROUND AND AIM OF THE STUDY: An increasing number of elderly patients are now requiring mitral valve surgery (MVS). However, due to a perceived increase in risk of morbidity and mortality following cardiac surgery, many elderly patients tend to be neglected or not referred for surgery. METHODS: The outcome of MVS in terms of hospital morbidity and mortality, length of intensive care unit (ICU) and hospital stays, and change in NYHA functional class and quality of life following surgery was assessed in 43 elderly patients (18 males, 25 females; median age 77 years (IQR 75-82 years)) who underwent primary open mitral valve repair (MVRr) or replacement (MVR) between November 1994 and September 1997. Their preoperative clinical characteristics, incidence of hospital morbidity, hospital mortality and length of ICU and hospital stays following MVS were recorded. At follow up, NYHA class was assessed and quality of life parameters monitored using the SF-36 questionnaire. RESULTS: At surgery, 69% of patients were in NYHA class III/IV, 36% underwent non-elective surgery and 44% had symptoms of more than three years' duration. Among patients, 80% presented with mitral incompetence and MVRr was undertaken in 51%. The median bypass and cross-clamp times for MVRr were significantly longer than for MVR. After surgery, 98% of patients required inotropic support, 9% renal dialysis, and 42% ventilatory support for >24 h. In addition, 37% developed respiratory complications, 12% renal failure, 19% needed re-exploration for bleeding, and 5% suffered a stroke. The mean ICU stay after surgery was three days; average in-hospital stay was 10 days. The 30-day mortality rate was 22.7% after MVRr and 38% after MVR. There was a significant improvement in energy, and role limitation due to physical and mental health after MVS. CONCLUSIONS: Elderly patients underwent MVS, usually after a degree of clinical deterioration. Although morbidity and mortality following mitral valve surgery were high, at follow up there was a significant improvement in both symptoms and quality of life of survivors.

Contamination of the surgeon's bare and gloved fingertips in cardiac operations.

The surgeon's bare fingertips and the external surface of gloved fingertips were examined for contamination by bacteria during the course of 27 cardiac surgical operations. Following the surgical scrub, positive colony counts were obtained in 20 (74%) of bare fingertip impressions (median colony count 4 [inter-quartile range, IQR, 0-9)], while at the conclusion of surgery positive counts were obtained in 15 (55.6%) fingertip impressions (median count 1 [IQR 0-6]; range 0-247; paired Wilcoxon test p = NS). Furthermore, positive colony counts at the start of the operation were obtained in none of the gloved fingertip impressions and at conclusion of surgery in 17 (62.9%) of the gloved fingertip impressions (median count 2 [IQR 0-6] p = 0.0002). There was no significant relationship between the total colony count on gloved fingertip impressions and the length of surgery (Pearson's r = 0.17, p = NS). Contrary to expectations there was no significant increase in the colony count on the bare fingertips at the conclusion of surgery. Although there was an increase in the bacterial count on the surgeon's gloved fingertips, this increase did not correlate with the length of surgery.