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Biomedical subjects

P G Magee

Publications and source records attributed to P G Magee.

17 recordsLinked to original sources
PubMed2001

Hypothetical ratings of coronary angiography appropriateness: are they associated with actual angiographic findings, mortality, and revascularisation rate? The ACRE study.

OBJECTIVE: To determine whether ratings of coronary angiography appropriateness derived by an expert panel on hypothetical patients are associated with actual angiographic findings, mortality, and subsequent revascularisation in the ACRE (appropriateness of coronary revascularisation) study. DESIGN: Population based, prospective study. The ACRE expert panel rated hypothetical clinical indications as inappropriate, uncertain, or appropriate before recruitment of a cohort of real patients. SETTING: Royal Hospitals Trust, London, UK. PARTICIPANTS: 3631 consecutive patients undergoing coronary angiography (no exclusion criteria). MAIN OUTCOME MEASURES: Angiographic findings, mortality (n = 226 deaths), and revascularisation (n = 1556 procedures) over 2.5 years of follow up. RESULTS: The indications for coronary angiography were rated appropriate in 2253 (62%) patients. 166 (5%) coronary angiograms were performed for indications rated inappropriate, largely for asymptomatic or atypical chest pain presentations. The remaining 1212 (33%) angiograms were rated uncertain, of which 47% were in patients with mild angina and no exercise ECG or in patients with unstable angina controlled by inpatient management. Three vessel disease was more likely among appropriate cases and normal coronaries were more likely among inappropriate cases (p < 0.001). Mortality and revascularisation rates were highest among patients with an appropriate indication, intermediate in those with an uncertain indication, and lowest in the inappropriate group (log rank p = 0.018 and p < 0.0001, respectively). CONCLUSION: The ACRE ratings of appropriateness for angiography predicted angiographic findings, mortality, and revascularisation rates. These findings support the clinical usefulness of expert panel methods in defining criteria for performing coronary angiography.

Adult↗
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↗
PubMed1995

Right ventricular failure in patients requiring left ventricular assistance.

Right ventricular failure may complicate isolated left ventricular assistance. In a series of 8 patients undergoing left ventricular assistance in postcardiotomy cardiogenic shock, right ventricular failure developed in 5, directly contributing to death in all cases despite initially satisfactory support. Difficulty in grafting a dominant right coronary artery was a common factor in all cases. Early consideration should be given to biventricular support under these circumstances.

Aged↗
PubMed1993

Coronary artery bypass surgery and minor aortic stenosis--to replace or not to replace?

Seven patients with a mean age of 65 years (range 50-76 years) who had minor aortic valve gradients (less than 25 mmHg) at preoperative cardiac catheterization underwent coronary artery bypass surgery without aortic valve surgery, but required a second operation for aortic valve replacement between five and nine years later because of symptomatic aortic valve stenosis with a valve gradient which had increased to between 60 and 100 mmHg. Serial hemodynamic observations in patients with aortic stenosis have demonstrated that the rate at which stenosis progresses is widely variable. However, replacement of aortic valves at the time of initial coronary artery surgery may subject the patients to an increased risk of operative mortality and prosthetic valve-related complications. On the other hand, the patient may miss the opportunity to obtain maximum benefit from valve replacement before deterioration of left ventricular function, particularly in the presence of coronary artery disease, and there are also the risks of resternotomy. We are currently inclined to replace the aortic valve in coronary patients with asymptomatic aortic stenosis, but our experience is not sufficient to draw final conclusions and the relevant literature does not provide a clear guidance. The aim of this publication is to expose this dilemma.

Aged↗
PubMed1989

A concealed impalement injury of the chest--an unusual intrathoracic foreign body.

Penetrating injuries of the chest in civilian practice are rare. A case is presented of an unusual injury with a large wooden chair fragment which remained concealed for several days until the development of life threatening complications. Aspects of the evaluation of penetrating thoracic injuries are discussed.

Acute Kidney Injury↗
PubMed1987

Ventricular septal rupture complicating myocardial infarction: is earlier surgery justified?

Fifty-five consecutive cases of ventricular septal rupture following myocardial infarction were reviewed in order to ascertain clinical and haemodynamic determinants of in-hospital mortality. Factors associated with a poor prognosis included clinical evidence of a poor haemodynamic state or biochemical evidence of impaired renal function. Twenty-six patients managed before 1982 (group 1) were then compared with 29 managed subsequently (group 2) when a policy of earlier surgical intervention had been adopted. Patients in group 2 were more haemodynamically compromised and had greater impairment of renal function. The surgical mortality in group 1 was 3 of 18 patients (17%) which was not significantly different from that in group 2 (7 of 22 patients, 32%). Earlier surgical intervention in ventricular septal rupture is frequently undertaken in critically ill patients whose prognosis is poor. However their surgical risk is not significantly increased and such an approach can therefore be justified as it may salvage some patients who otherwise would not survive.

Adult↗
PubMed1987

Results of surgical repair for dissection of the ascending aorta.

Between 1970 and 1986, 40 patients had surgical treatment for dissection of the ascending aorta at the London Chest Hospital. The overall hospital mortality was 27.5%. Preoperative renal impairment and age greater than or equal to 60 years were both associated with a significantly increased hospital mortality. In the long term one patient was lost to follow up. There have been two late deaths among the remaining 28 patients (mean follow up 4.4 years). The functional state of the survivors is good, with only three having any cardiac disability.

Adolescent↗
PubMed1979

Beneficial effects of pulsatile perfusion in the hypertrophied ventricle during ventricular fibrillation.

To assess the potential benefit of pulsatile perfusion inthe hypertrophied heart during fibrillation, 10 dogs with left ventricular hypertrophy, produced by previous supravalvular aortic banding, were used to compare linear and pulsatile perfusion in the fibrillating heart during total cardiopulmonary bypass. The mass spectrometer was used to measure subendocardial PCO2 and PO2 (PmCO2 and PmO2), and radioactive microspheres were utilized to measure myocardial blood flow in the same layers. Pulsatile perfusion was established using the recently develop "bubble tubing," which produces a pulse pressure of at least 20 mm Hg and can be used in a standard roller-pump apparatus. Both linear and pulsatile flows were compared at mean aortic root pressures of 80 and 50 mm Hg, and these four combinations of aortic root pressure and type of flow were employed for periods of 30 minutes each. Myocardial ischemia developed during linear coronary perfusion at 50 mm Hg, as evidenced by an elevation of PmCO2. Ischemia was not evident during pulsatile perfusion at the same mean pressure. Reversal ischemia was a result of increased myocardial blood flow and pulsatile perfusion, and this increase was shown to occur maximally in the deeper subendocardial layer. Ischemia was not eviden during linear or pulsatile perfusion at an mean perfusion pressure 80 mm Hg. Thus, if lower perfusion pressures are to be tolerated in patients with left ventricular hypertrophy, pulsatile perfusion with the bubble tubing technique may prevent the development of subendocardial ischemia or infarction.

Animals↗
PubMed1979

Comparison of myocardial protection with nifedipine and potassium.

Nifedipine, a slow-channel calcium blocker, is thought to provide useful myocardial protection during prolonged total ischemia and reperfusion. An isolated, isovolumic, feline heart model was used to asses the effectiveness of nifedipine in both cardioplegic (100 microgram/10 ml) and noncardioplegic (10 microgram/10 ml) doses for providing myocardial preservation during 90 minutes of hypothermic ischemic arrest and 45 minutes of normothermic reperfusion. Use of nifedipine was compared to hypothermia (27 degrees C) alone and to hypothermia with potassium cardioplegia. Ventricular function was assessed by recovery of isovolumic left ventricular developed pressure and dP/dt. Myocardial carbon dioxide tension (PCO2) and myocardial oxygen tension (PO2) were measured by mass spectrometry. Potassium cardioplegia and the higher dose of nifedipine resulted in immediate asystole. The rates of rise of PCO were greatest in the group receiving 10 microgram nifedipine and in the control group. The rates of rise in the two cardioplegic groups were significantly lower. Recovery of ventricular function was significantly lower with low-dose nifedipine than with potassium cardioplegia. Higher dose nifedipine resulted in a return of function, which was no different than with potassium cardioplegia. Morphologic protection was better with higher dose nifedipine and potassium cardioplegia than with either low-dose cardioplegia or hypothermia alone. These results demonstrate that nifedipine in a cardioplegic dose results in preservation of myocardial structure and function that is similar to that obtained with potassium cardioplegia. In lower noncardioplegic dose, nifedipine does not appear to offer additional protection compared to hypothermia alone. Whether persistent depression of ventricular contractility will limit nifedipine's clinical usefulness as a myocardial protection agent will require further study.

Animals↗