Polymerase chain reaction diagnosis in culture-negative prosthetic valve methicillin-resistant Staphylococcus aureus endocarditis in a patient with chronic liver disease.

We report the use of polymerase chain reaction for the diagnosis of prosthetic valve methicillin-resistant Staphylococcus aureus endocarditis in a patient with chronic liver disease where conventional laboratory testing failed. This case highlights the diagnostic and therapeutic potential of molecular techniques in the management of culture-negative endocarditis.

The aortic Elan stentless aortic valve: excellent hemodynamics and ease of implantation.

The superior performance of stentless aortic valves with improved left ventricular hypertrophy regression and greater effective orifice area is proven. The Aortech Elan stentless valve (AESV) is a glutraldehyde preserved porcine valve with a pericardial reinforced inflow tract and a scalloped outflow to reduce bulk. We present the early results of AESV implantation at our institution. The first 41 consecutive recipients of the AESV at our unit, between November 1999 and December 2000, were studied. Mean preoperative New York Heart Association functional class (NYHA) status was 3.00 +/- 0.1. Patients requiring a bioprosthesis with suitable anatomy routinely received this implant. The AESV was implanted, either with an interrupted or continuous suture to the inflow tract and a continuous suture to the outflow tract. Transthoracic echocardiography was performed at 6 to 9 weeks after surgery, and aortic transvalvular gradients, flow velocities, and effective orifice areas (EOA) were calculated. In the early postoperative period, two patients with coronary artery disease died of low cardiac output. Echocardiography demonstrated competent valves. At follow-up, one patient was shown to have mild to moderate perivalvular leak with minimal symptoms. Two patients with aortic regurgitation secondary to bacterial endocarditis had no evidence of infection at 3 months after surgery. Mean transvalvular gradient was 6.91 +/- 0.87 mm Hg and mean effective orifice area was 1.18 +/- 0.04 cm(2)/m(2) at a mean of 8.4 weeks after surgery. AESV recipients for native aortic endocarditis were free from infection and regurgitation. The Elan stentless aortic valve demonstrates excellent early hemodynamic results, with very low transvalvular gradients, good flow characteristics and low regurgitation incidence. Ease of implantation is evidenced by favorable ischemic times. This valve may offer an option to homograft in acute aortic endocarditis. Long-term results are awaited.

Six-year follow-up of the Toronto stentless porcine valve.

Stentless valves in the aortic position have been shown to have superior hemodynamic performance to stented valves and have now been shown to increase survival. We report the medium-term results from a single center of 229 Toronto (SPV) aortic valve replacements between 1994 and 2000. The mean age of the patients was 72 years (range, 41-87 years). The mean Euroscores were 6.2 (+/-0.13) and Parsonnet scores of 16.8 (+/-0.5). Concomitant coronary artery bypass grafting was performed in 125 (55%) of patients, eight patients had additional mitral valve replacements and ten were redo procedures. Hospital mortality was 3.5%. The mean follow-up period was 45 (7-81) months. The actuarial survival was 92.4% (+/-1.4%) at one year and 76.2% (+/-3.5%) at five years. There were 37 late deaths (4.7% per patient years). There were 3 patients with prosthetic valve endocarditis (0.38% per patient years), two of whom died. Stroke occurred in 13 patients (1.6% per patient years), five of whom died. None of these events were known to be valve related. There was no incidence of structural valve dysfunction and no valves have been explanted. At follow-up, the mean transvalvular gradient was 4.2 mm Hg (range, 0.9-12.7 mm Hg). No aortic incompetence (AI) was seen in 88% of patients with trivial or mild AI in 11% of patients and moderate AI in one patient. This series shows acceptable early and medium-term results in an elderly population with a high incidence of coronary artery disease.

A three year experience with the toronto stentless porcine valve.

In the three year period from March 1994, 112 Toronto Stentless Porcine Valves (SPV TM) were implanted in the Western Infirmary, Glasgow. There were 55 males and 57 females aged between 45 and 86 years (mean 70.9 +/- 7.2 yrs). The mean preoperative aortic gradient was 89 +/- 27 mmHg. Fifty-three patients (47%) had an isolated first time aortic valve replacement. Myocardial revascularisation was carried out in 51 patients (46%) with a mean of 1.7 +/- 0.9 coronary bypass grafts per patient. Six patients (5.3%) had associated mitral valve procedures and six patients (5.3%) had previous open heart surgery. Four patients (3.6%) had a minimally invasive procedure. There was one perioperative death (0.9%) which was not valve related. Of the 111 survivors there were three late deaths (cerebrovascular accident at two months and congestive cardiac failure at two months and four months). Two patients developed prosthetic valve endocarditis at three and five months respectively, one requiring a repair of a periprosthetic leak. To compare the effects of stented and stentless prostheses on early haemodynamic function and late left ventricular mass regression, a prospective randomized clinical trial was conducted. Following valve sizing, 20 patients were randomized to receive a Carpentier-Edwards SAV stented bioprosthesis (mean annular size-25.3 mm, mean valve size-23 mm) of which eight also had bypass grafts. Twenty patients were randomized to receive a Toronto SPV (mean annular size-25.5 mm, mean valve size-26 mm) of which nine had bypass grafts. The stentless valve group had a longer ischaemic time (77.9 +/- 20.9 min v 60.9 +/- 21.9 min) and bypass time (101.7 +/- 27.1 min v 82.9 +/- 20.2 min). Using continuous cardiac output monitoring, no statistically significant differences were found in early haemodynamic indices although the stentless group required less inotropes and had a shorter ventilation time (16.1 +/- 4.2 hrs v 55.2 +/- 104.9 hrs) and intensive care stay (1.1 +/- 0.2 days v 4.6 +/- 8.3 days). Mean and peak aortic gradients one week postoperatively were lower in the stentless group (5.6 +/- 3 mmHg v 8.9 +/- 2.3 mmHg and 12.5 +/- 7.8 mmHg v 24.4 +/- 8.8 mmHg respectively). Magnetic resonance imaging at six months showed a 15% reduction in the end systolic muscle mass index in the stented group but a greater reduction of 29% in the stentless group. This study shows that despite requiring a more demanding technique of insertion, aortic valve replacement with the Toronto stentless porcine valve can produce satisfactory early clinical results.

Emergency bypass without bypass!

We present 2 cases of failed coronary angioplasty, with hemodynamic compromise, where emergency coronary artery bypass grafting was performed without cardiopulmonary bypass. The hypodynamic nature of the stunned myocardium in this circumstance allows this technique to be applied with relative ease to accessible vessels. As a consequence, reduced morbidity and hospital stay can be anticipated.

Acute-phase responses to cardiopulmonary bypass in children weighing less than 10 kilograms.

BACKGROUND: Cardiopulmonary bypass induces a systemic inflammatory response. This study investigated, in a pediatric population, cytokine-induced responses and their potential modification by intraoperative steroid administration. METHODS: Markers of the acute-phase response were measured perioperatively in 24 children weighing less than 10 kg undergoing cardiac operations. Those having operations with cardiopulmonary bypass were randomized to receive either no steroid (group I, n = 8) or 10 mg/kg methylprednisolone in the pump prime (group II, n = 10); patients undergoing nonbypass procedures were controls (group III, n = 6). RESULTS: In all groups, plasma interleukin-6 level was elevated (p < 0.01) above baseline throughout the post-operative period, peaking earlier in group I. Levels of C-reactive protein peaked at 48 hours, and postoperative core temperature was raised in all groups. Levels of interleukin-6 from 2 to 6 hours and C-reactive protein at 24 hours postoperatively were greater (p < 0.05) in group I than in group II. Maximum interleukin-6 level, C-reactive protein level, and temperature were all significantly greater in group I than in group III. Maximum interleukin-6 level correlated with maximum C-reactive protein level in group I only (rs = 0.76; p < 0.05) and showed no association with temperature. Duration of bypass did not correlate with levels of interleukin-6. CONCLUSIONS: This study demonstrated a marked acute-phase response to operation; the greater response to procedures with cardiopulmonary bypass was abrogated by intraoperative steroid administration. The importance of interleukin-6 as an inducer of acute phase proteins after bypass is supported by its association with C-reactive protein levels, but other factors must be important in the induction of pyrexia.

Sinus venosus defect: single-patch repair with caval enlargement.

We present a single pericardial patch repair of the sinus venosus defect with anomalously connected pulmonary veins, incorporating enlargement of the superior vena cava. In our small series to date this procedure has been carried out without morbidity or mortality. Noninvasive follow-up by echocardiography and electrocardiography, over the short term, has not detected any stenosis of the venous pathways or sinus node dysfunction.

Pulmonary extraction and left atrial secretion of atrial natriuretic factor during cardiopulmonary bypass surgery.

We have investigated the role of the lungs in the extraction of atrial natriuretic factor (ANF) by measuring plasma levels in samples taken from the central circulation in 12 patients (mean age 59 years; range 43 to 68) undergoing cardiac surgery. We also investigated the effects of cardiopulmonary bypass on ANF levels. ANF levels (mean +/- SD) were lower in pulmonary venous samples (41 +/- 20 pg/ml) than in pulmonary arterial samples (54 +/- 18 pg/ml; p less than 0.001), demonstrating 24% extraction of ANF by the lungs. Both left atrial (47 +/- 23 pg/ml) and systemic arterial levels (52 +/- 22 pg/ml) were higher than pulmonary venous levels (both p less than 0.05), indicating secretion of ANF into the left side of the heart. During cardiopulmonary bypass, plasma ANF concentration fell from 68 +/- 23 pg/ml before aortic cross-clamping to 35 +/- 13 pg/ml 10 minutes after and 28 +/- 9 40 minutes after the application of clamps (both p less than 0.001). A rebound rise to 122 +/- 33 pg/ml followed the release of the clamp (p less than 0.001). This study demonstrates that ANF is extracted by the lungs and secreted directly into the left side of the heart. The considerable fall in plasma levels that was observed during aortic cross-clamping might contribute to the neurohumoral activation and increased peripheral resistance observed after prolonged cardiopulmonary bypass and to the risk of renal ischemic injury.

Mechanical versus biological heart valves: a ten-year comparison in a single centre.

Between January 1977 and December 1986, 1606 Bjørk-Shiley tilting disc prostheses (BS) and 1346 Carpentier Edwards porcine prostheses (CE) were implanted in 1300 and 1156 patients, respectively, at the same institution. During the time of implantation, both valves have developed: the BS through standard disc and convexo-concave to monostrut, and the CE valves from standard to supra-annular. Newer valve types were used where applicable as they became available. Preoperative status in respect of age and cardiac rhythm were similar. There were significantly more females (64% BS: 54% CE, P less than 0.001); worse NYHA grade (74% Grade 111 and IV-BS: 56% 111 and IV-CE, P less than 0.001) more closed heart surgery (26% BS: 18% CE, P less than 0.001) and more previous open heart surgery (11.6% BS: 8.9% CE, P less than 0.001) in the BS group. All BS patients were anticoagulated and 49% of mitral CE patients and 7% of aortic CE patients were anticoagulated. There was no significant difference between the two groups in hospital mortality (BS 7.2%: CE 6.3%), late mortality (BS 2.5%/patient year: CE 3.2%/patient year) overall incidence of systemic embolism (BS 1.3%/patient year: CE 1.4/patient year), prosthetic valve endocarditis (BS 0.7%/patient year: CE 0.9%/patient year), valve failure (BS 0.5%/patient year: CE 0.9%/patient year) or peri-prosthetic leak (BS 1.2%/patient year: CE 1.3%/patient year). The incidence of systemic embolism in the aortic position was lower with the BS prosthesis (BS 0.2%/patient year: CE 1.2%/patient year, P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation of a new fibre-optic pulmonary artery catheter in intensive care. A preliminary study.

We have assessed the performance of a new fibre-optic pulmonary artery catheter for the measurement of mixed venous oxygen saturation. The results obtained from this catheter compare well with those using standard techniques. Other information from the catheter allows oxygen consumption to be easily calculated and again the results obtained agree closely with those measured using standard techniques.