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K J MacArthur

Publications and source records attributed to K J MacArthur.

8 recordsLinked to original sources
PubMed1998

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.

Aged↗
PubMed1996

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.

Acute-Phase Reaction↗
PubMed1996

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.

Aged↗
PubMed1995

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.

Echocardiography↗
PubMed1992

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.

Atrial Function, Left↗
PubMed1988

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)

Adolescent↗
PubMed1984

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.

Adult↗