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Biomedical subjects

R K Walesby

Publications and source records attributed to R K Walesby.

At least 19 recordsLinked to original sources
PubMed2001

A spontaneous ductal aneurysm presenting with left recurrent laryngeal nerve palsy.

A 76-year-old man was found to have a left recurrent laryngeal nerve palsy, due to a spontaneous patent ductus arteriosus aneurysm. Ortner's syndrome (left recurrent laryngeal nerve palsy caused by cardiovascular pathology) secondary to patent ductus arteriosus aneurysm has not previously been described in the literature. We present a case, illustrated with surface rendering computer tomogram reconstructions.

Aged↗
PubMed2000

How silent is perioperative myocardial ischemia? A hemodynamic, electrocardiographic, and biochemical study in patients undergoing coronary artery bypass graft surgery.

OBJECTIVE: To analyze the relationship among Holter electrocardiogram (ECG) recordings, hemodynamic measurements indicative of global myocardial oxygen balance, and serum cardiac troponin I concentrations (cTnI) in the early postoperative period after coronary artery bypass graft (CABG) surgery. DESIGN: Prospective observational study. SETTING: University teaching hospital. PARTICIPANTS: Thirty patients undergoing CABG surgery. INTERVENTIONS: ECG measurements consisted of Holter and standard ECG recordings. Hemodynamic measurements included heart rate, systolic and diastolic blood pressure (SBP, DBP), pulmonary capillary wedge pressure, and cardiac index (CI). Derived indices included tension time index (TTI), rate-pressure product, pressure work index (PWI), and endocardial viability ratio (EVR). Serial measurements of cTnI concentrations were measured postoperatively; the area under the cTnI concentration time curve was calculated for each patient (AUC cTnI). MEASUREMENTS AND MAIN RESULTS: Episodes of myocardial ischemia were associated with small but significant rises in SBP (p = 0.01), DBP (p = 0.001), and TTI (p = 0.005) compared with periods without ischemia in the same patients. Serum cTnI concentrations 24 hours after cardiopulmonary bypass (p = 0.03) and AUCcTnI (p = 0.01) values were greater in patients who developed ECG myocardial ischemia compared with patients who did not. CONCLUSIONS: The small changes in hemodynamics seen, although statistically significant, are unlikely to be the primary cause of the ischemia. They more likely reflect an independent process that causes or occurs as a result of ischemic episodes. Ischemic episodes detected by the Holter monitor are associated with significant release of cardiac troponin from the myocardium.

Adult↗
PubMed1998

Helicobacter pylori and upper gastrointestinal bleed in heart valve surgery.

OBJECTIVE: This study was designed to evaluate objectively the incidence of Helicobacter pylori infection and upper gastrointestinal (GI) bleeding in patients following heart valve replacement surgery. Since the discovery of Helicobacter pylori, its association with gastritis, peptic ulceration and upper GI bleed have been extensively studied. Anticoagulation of patients with mechanical heart valve prostheses is a prerequisite for the prevention of valve thrombosis and thrombo-embolic events. However anticoagulation can have its complications, notably that of upper GI bleeding. METHODS: Patients were assessed in routine postoperative outpatient clinics following cardiac valve replacement surgery. This assessment comprised initially of a questionnaire reflecting the symptomatology of upper GI bleeding and its subsequent management. With informed consent, a small sample of blood was obtained by stilette. The Helicobacter pylori status was assessed by measuring the presence of antibodies (immunoglobins) to Helicobacter pylori in a commercially available test kit, the Rapid Helisal Test. In this preliminary study 150 consecutive patients were scrutinised and their responses to the questionnaire were collected and compared with the Helisal test. RESULTS: From the 150 patients studied, 37 patients were found to be positive to the Helisal test for Helicobacter pylori infection, representing 24.6% of all the cohorts. Of these 37 patients, eight gave a positive history of upper GI bleed; five requiring hospital admission with three requiring urgent upper GI endoscopy. Although these eight patients represent only 4.4% of the total group, it is significant to note that this represents 21.6% of those patients found to be Helicobacter pylori positive. There were no GI complications in any of those tested negative. There was an increasing incidence of Helicobacter pylori infection in the older age group of patients. CONCLUSIONS: Helicobacter pylori infection is a common infection with serious consequences in heart valve surgery. For those requiring anticoagulation, the incidence of serious consequential upper GI bleed is significantly higher in the presence of this infection. Preoperative or immediate postoperative eradication of the organism is mandatory in those patients requiring indefinite anticoagulation.

Adult↗
PubMed1998

Venous gangrene of the lower limbs following aortic valve replacement for native valve endocarditis.

Bacterial endocarditis is a complex disease associated with high morbidity and mortality with complications that include acute heart failure and arterial embolism. Venous thrombosis of the lower limbs is not uncommon following all forms of surgery, but infrequent following cardiac surgery, and rarely progresses to venous gangrene. We report a case of bilateral lower-limb venous gangrene, in a 49-year-old female who underwent aortic valve replacement for native valve endocarditis. The possible aetiology of this complication is discussed.

Aortic Valve↗
PubMed1997

Re-do cardiac surgery in patients over 70 years old.

OBJECTIVE: This study was conducted in order to determine the outcome of cardiac re-operations in patients over the age of 70. METHODS: All patients who underwent 're-do' cardiac surgery at our institution, between January 1987 and October 1995 were identified. The case notes of patients over the age of 70 were reviewed retrospectively and follow-up was by telephone. RESULTS: A total of 687 re-do operations were performed during this 8 years and 9 months period. Operations, 110 (16%) were on patients aged 70 years and over (CABG 54, MVR 32, AVR 9, AVR + MVR 5, MVR + CABG 4, AVR + CABG 3, repair of paraprosthetic leak 2 and closure of VSD 1). Operations, 63 (57%) were elective and 42 (38%) were urgent. The median age was 73 years (range 70-82) and 64 patients (58%) were male. Pre-operatively, 78 patients (72%) were NYHA functional class III/IV and 55 (50%) had angiographically impaired left ventricular function (ejection fraction < 50%). The overall operative mortality was 7% (8/110). Median ITU stay was one night (range 1-21) and hospital stay was 7 days (range 5-35). Major in-hospital complications included resternotomy in five patients (5%), permanent stroke in three (3%), renal failure requiring haemodialysis in two (2%) and heart block requiring permanent pacing in two (2%). At a median follow-up of 34 months (range 2-101), 69 of the 77 patients alive at follow-up (90%) were NYHA functional class I/II. CONCLUSIONS: 'Re-do' cardiac surgery in patients over the age of 70 carries an acceptable operative morbidity and mortality with a good functional improvement at medium term follow-up.

Aged↗
PubMed1996

Early single centre experience with 192 Sorin Bicarbon valves.

In 1990 Sorin Biomedica introduced a new pyrolytic bileaflet heart valve, the Bicarbon, developed using innovative design concepts with new materials, housing, hinge mechanism, leaflet curvature and sewing ring construction. From June 1991 to May 1995, 192 bicarbon valves were implanted in 177 patients by one team. The patient population was 102 males and 75 females with an age range from 16 to 82 years (mean 62.5 years). Ninety-six were AVR, 68 MVR, 12 double valve replacements, 2 patients received another type of bileaflet valve as did the triple valve replacement. Overall hospital mortality was 5.2%. For MVR the mortality was 12.7%; for AVR it was 4.7%. There were no deaths associated with double or triple valve replacement. Five deaths were at reoperation, 2 at emergency operation, 1 aortic dissection, 2 for endocarditis, none of the deaths were valve related. One patient had a haemorrhage due to inadequate control of Warfarin therapy. Four valves were explanted: 3 mitrals for paravalvular leaks and 1 aortic for endocarditis. No patients showed any evidence of thromboembolic complications and there were no late deaths. All the surviving patients have improved their preoperative clinical status. Maximum follow-up is nearly 4 years, mean 32 months (range 1-47). Twenty one patients underwent haemodynamic evaluation by Doppler echocardiography. The mean pressure drop across 12 mitral valves was 8.34 mmHg (mean size 29.7 mm) and for 9 aortic valves it was 15.85 mmHg (mean size 23). Based on these results we are of the opinion that the Bicarbon valve is equivalent to the best of other bileaflet valves currently available.

Aortic Valve↗
PubMed1996

One hundred patients' experience with the Jyros valve.

The ideal mechanical valve abolishes all potential areas for blood stagnation and hence the potential for micro-emboli and clot formation. This problem has been addressed by the innovative design of the Jyros valve which has evolved from the technology available from Russian space research. The valve comprises two pyrolytic carbon leaflets which can rotate within the solid carbon housing to either align themselves to the optimum haemodynamic configuration, or to respond by rotation either continuous or intermittent, according to the degree of swirl on the inflow profile. This Jyros mechanical heart valve has been assessed in vivo at the London Chest Hospital since August 1992 where the series of unselected patients constitutes the largest single user experience available. 107 valves were implanted in 100 patients of age range 33 to 80 years. 23 patients were re-replacement for failed xenograft and 26 underwent concomitant revascularisation. 92 patients left hospital and 4 died later all from non-valve related causes. Two valves were explanted for endocarditis (one pre-existing) but successfully re-replaced. There have been no late thrombo-embolic events. Two patients with AVR & CABG had strokes at 8 months. There is no excessive haemolysis in excess of that detected for any mechanical valve nor any mechanical valve-related failure. Rotation of the valve is variable and can be visualised by 2D and M mode echo and by X-ray screening as the leaflets are impregnated with Boron carbide. Half of the valves rotate constantly and a quarter intermittently. There appears to be no disadvantage to patients in whom no valve rotation could be demonstrated. We have found that the theoretical potential of performance have been achieved.

Adult↗
PubMed1996

Does activated neutrophil depletion on bypass by leukocyte filtration reduce myocardial damage? A preliminary report.

An important factor in the production of myocardial damage following cardiopulmonary bypass in the creation of oxygen derived free radicals. Few sources for these radicals have been identified but experimentally activated neutrophils are known to release free radical which contribute to myocyte necrosis. The aim of this pilot study was to identify whether, by depleting patients of leukocytes and particularly neutrophils on bypass, a better degree of myocardial protection could be observed using specific identifiers of myocardial damage. Ten patients undergoing urgent coronary artery bypass for unstable angina with impaired left ventricular function were leuko-depleted using a PALL medical leukocyte filter in the extra corporeal circulation together with leukocyte depletion of all transfused blood. A similar group of matched controls had only an arterial line filter without leukodepletion. All patients were operated by one surgeon using identical techniques of intermittent cross clamping and fibrillation at moderate hypothermia. Full blood count, Glutathione, Troponin T and CPK/MB were measured before, during and at identified intervals up to 72 hour after bypass. Preliminary results show little change in the total leukocyte count but the Troponin T and CPK/MB values were lower in the filtered group than in the control group and an increased level of total Glutathione in the filter group showed that there was less oxidated stress on the myocardium. Currently this filter is an expensive addition to bypass surgery but these preliminary results suggest that activated neutrophil depletion on bypass may be of benefit to patients with unstable angina, impending myocardial necrosis and low ejection fraction.

Aged↗
PubMed1994

Emergency surgical revascularisation for coronary angioplasty complications.

OBJECTIVES: To evaluate trends in referrals for emergency operations after percutaneous transluminal coronary angioplasty (PTCA) complications; to analyse morbidity and mortality and assess the influence of PTCA backup on elective surgery. DESIGN: A retrospective analysis of patients requiring emergency surgical revascularisation within 24 hours of percutaneous transluminal coronary angioplasty. PATIENTS: Between January 1980 and December 1990, 75 patients requiring emergency surgery within 24 hours of percutaneous transluminal coronary angioplasty. SETTING: A tertiary referral centre and postgraduate teaching hospital. RESULTS: 57 patients (76%) were men, the mean age was 55 (range 29-73) years, and 30 (40%) had had a previous myocardial infarction. Before PTCA, 68 (91%) had severe angina, 59 (79%) had multivessel disease, and six (8%) had a left ventricular ejection fraction of less than 40%. A mean of 2.1 grafts (range one to five) were performed; the internal mammary artery was used in only one patient. The operative mortality was 9% and inhospital mortality was 17%. There was a need for cardiac massage until bypass was established in 19 patients (25%): this was the most important outcome determinant (P = 0.0051) and was more common in those patients with multivessel disease (P = 0.0449) and in women (P = 0.0388). In 10 of the 19 cases a vacant operating theatre was unavailable, the operation being performed in the catheter laboratory or anaesthetic room. These 19 patients had an operative mortality of 32% and inhospital mortality of 47%, compared with 2% and 7% respectively for the 56 patients who awaited the next available operating theatre. Complications included myocardial infarction, 19 patients (25%); arrhythmias, 10 patients (3%); and gross neurological event, two patients (3%). The mean intensive care unit stay was 2.6 days (range 1 to 33 days) and the mean duration of hospital admission was 13 days (range 5-40 days). CONCLUSIONS: Patients undergoing emergency surgery after PTCA complications have a substantially increased inhospital mortality and morbidity. PTCA in this unit continues to require surgical cover. Delays in operating on stable patients in centres which operate a "next available theatre" backup policy may not differ from some units performing PTCA with offsite cover for PTCA complications. Particularly in the presence of multivessel disease, however, PTCA complications may be associated with the need for "crash" bypass and such patients are unlikely to survive hospital transfer. The proportion of patients requiring "crash" bypass has increased during the period reviewed because of the extent of disease in the emergency surgical group increased. These results indicate that surgery should not be denied to these patients.

Adult↗
PubMed1994

The superior mediastinal approach to hepatic malignancy.

A 26-year-old man presented with superior vena caval obstruction. He underwent excision of a malignant teratoma which contained benign hepatic tissue. Three years later he represented with a recurrence and underwent a second resection. Histology of the resected specimen demonstrated hepatocellular carcinoma arising in the hepatic component of the recurrent malignant teratoma intermediate.

Adult↗
PubMed1993

A comparison of fenoldopam and nitroprusside in the control of hypertension following coronary artery surgery.

A prospective trial to compare the effects of the synthetic dopaminergic (DA1) agonist, fenoldopam (FEN), with sodium nitroprusside (SNP) for control of blood pressure following coronary artery bypass graft surgery was carried out in 20 patients. Patients were randomly allocated to receive either FEN or SNP when the systolic arterial blood pressure (SAP) rose above 130 mmHg. The goal of therapy was to achieve a stable control of blood pressure below 130 mmHg at a level at least 25 mmHg below the pretreatment value. Treatment was then continued for 2 hours. Hemodynamic measurements were made before treatment, after stable control of blood pressure had been achieved, and thereafter at 30, 60, and 120 minutes. Urine output, sodium, potassium, and creatinine clearance were also measured during the study. Both SNP and FEN caused a rapid and significant fall in SAP (P < 0.001) and a fall in systemic vascular resistance (P < 0.001). FEN caused an increase in cardiac index (P < 0.001) and in stroke volume (P < 0.001) in contrast to SNP. Urine output and potassium clearance fell with SNP (P < 0.05) in contrast to FEN. Thus, FEN would appear to control SAP as effectively as SNP, but may have more beneficial effects on cardiac output and some aspects of renal function.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed1993

Progress in the diagnosis and management of aspergillosis in bone marrow transplantation: 13 years' experience.

Over 13 years, we have seen 16 cases of proven invasive aspergillosis in 446 bone marrow transplant recipients, an incidence of 3.6%. The incidence of infection is low in patients with uncomplicated allogeneic or autologous bone-marrow transplants (< 2% and 0, respectively). Of the 16 episodes following transplantation, 10 occurred in patients with late transplant complications who were no longer in protective isolation. In patients who had focal pulmonary lesions (as diagnosed by computed tomographic scanning), culture of bronchoalveolar lavage (BAL) fluid was not an effective diagnostic procedure. In diffuse pulmonary disease due to Aspergillus, culture of BAL fluid had a sensitivity of 100%. Aspergillus species were isolated from an additional six patients who had no evidence of invasive aspergillosis. Graft rejection was a significant predisposing factor for the development of invasive aspergillosis (P < .001, log-rank test), and in our hospital, these patients now receive intravenous amphotericin B as prophylaxis. None of the six patients whose chest roentgenograms showed abnormalities before transplantation and who underwent surgical resection as part of the treatment for invasive aspergillosis developed recurrent infection.

Adolescent↗
PubMed1993

Isradipine and the coronary circulation.

Isradipine has been shown to be an effective vasodilator in different vascular beds. Experimental evidence suggests that isradipine is a potent coronary vasodilator, and this is supported by clinical studies in both cardiology and cardiac surgery. Furthermore, in these studies, coronary vasodilation was not accompanied by evidence of any significant effect on cardiac contractility or conduction. It can be concluded that the cardiac effects of isradipine will ultimately prove to be beneficial in patients undergoing myocardial revascularization.

Animals↗