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Biomedical subjects

C G Missouris

Publications and source records attributed to C G Missouris.

At least 19 recordsLinked to original sources

Intracerebral haematoma masquerading as ventricular standstill.

An 82 year old man was referred to the emergency room by his general practitioner for a right frontoparietal headache. The preceding day he had tripped and fallen, hitting the back of his head on the floor. Computed tomography showed a cortical contre coup haematoma. In view of ventricular standstill noted on ECG, a temporary pacing wire was inserted and a dual chamber permanent pacemaker was subsequently implanted. Intracerebral bleeding was treated conservatively and the patient made a good recovery. All patients admitted with head injury and sinus bradycardia or sinus arrest should be nursed at 15 degrees to 30 degrees with instructions to avoid the head up and supine positions. Furthermore, brain CT should be promptly recorded to assess for intracerebral haematoma and raised intracranial pressure and, if they are confirmed, these patients with cardiovascular compromise should benefit from close collaboration between neurosurgeon and cardiologist. Urgent pacing should be considered for all patients with head injury who experience symptomatic bradycardia or ventricular standstill.

Accidental Falls↗

Percutaneous transluminal renal artery angioplasty: who benefits most?

We set out to assess the long-term benefits of renal percutaneous transluminal angioplasty (PTA) in 107 consecutive hypertensive patients with atheromatous renal artery stenosis. During 12-month follow-up, blood pressure fell to normal levels in 10 (8.8%) patients and improved in 76 (67.3%); renal function improved or remained stable in 74% of patients. In patients with atheromatous disease, renal angioplasty was most successful in those with stenosis in a single functioning kidney, and in nine patients who presented with symptoms and signs of heart failure, in the absence of overt ischaemic or valvular heart disease. In the latter group, renal PTA resulted in a large loss of sodium and water, resolution of the 'apparent' heart failure, and a marked improvement in blood pressure and renal function. It is suggested that all hypertensive patients with haemodynamically significant renal artery stenosis (and/or mild to moderate impairment in renal function), should be considered for renal PTA. Patients with atheromatous stenosis in a single functioning kidney, and those who present with signs of sodium and water retention, are likely to benefit most.

Adult↗

Coronary heart disease in the statin and aspirin era: are results of clinical trials being put into practice?

BACKGROUND: We studied the impact of recent advances in coronary prevention by assessing cardiovascular risk factors and their management in 98% of patients admitted to a coronary care unit with acute myocardial infarction (AMI) between January and December 1998 [177 patients, mean age 66+/-1 (S.E.M.) years, 114 males]. METHODS AND RESULTS: Sixty-two patients had a history of coronary heart disease (CHD). One in four of them was still smoking and 27% had a recorded history of hyperlipidaemia. Only 12 patients with known CHD (19%) were on lipid-lowering treatment. Total cholesterol was above 5 mmol/l in 98/168 (58%) of the patients and LDL-cholesterol was above 3 mmol/l in 91/148 (62%) of the patients. Twenty-eight patients (16%) died during the hospital stay (age 74+/-2 years). Of 149 patients discharged from hospital, 101 (68%) were treated with a statin, including 85% of the patients with a total fasting cholesterol on admission above 5 mmol/l and 91% with LDL-cholesterol on admission above 3 mmol/l. Sixty-three percent of the patients on a statin were on a dose below that shown in clinical trials to reduce cardiovascular events. CONCLUSIONS: Unrecognised and ineffectively treated cardiovascular risk factors were common among patients with documented CHD who were admitted with AMI. Our study provides important background for the implementation of guidelines for the prevention of CHD.

Journal Article↗

Platelet sodium-hydrogen exchanger activity and left ventricular mass.

INTRODUCTION: The sodium-hydrogen exchanger (NHE) is integral to the processes that facilitate cell growth and may contribute to the development of left ventricular hypertrophy. The aim of this study was to examine the relationship between platelet sodium-hydrogen exchanger activity and left ventricular mass index (LVMI). METHODS: Twenty male untreated Caucasians (mean age +/- s.d.: 48 +/- 13; body mass index: 29 +/- 4 kg/m(2)) with a wide range of blood pressures were studied (mean BP: 152 +/- 22/93 +/- 15 mm Hg; range: 115-190/61-117 mm Hg). Sodium-hydrogen exchanger activity was determined as the rate of sodium-dependent recovery of intracellular pH in isolated platelets loaded with BCECF and acidified to pH 6.25 using nigericin. LVMI was calculated from measurements made by M-mode echocardiography. Associations between continuous variables were examined using parametric tests. RESULTS: The mean rate of pHi recovery was 0.15 +/- 0.03 dpHi/s (range: 0.09-0.21). Mean LVMI was 120 +/- 32 g/m(2) (range: 56-178) and was not significantly correlated with either systolic (r = 0.39, P = 0.09) or diastolic blood pressure (r = 0.27, P = 0.3). Platelet NHE activity was not significantly correlated with LVMI (r = 0.06; P = 0.8). Platelet NHE activity was not significantly different between subjects with (n = 7 with LVMI >131 g/m(2)) and without left ventricular hypertrophy (n = 13). CONCLUSIONS: The results of this study show that platelet NHE activity is not significantly correlated with LVMI. These data contrast with previously described correlations of LVMI with exchanger activity measured in leucocytes and erythrocytes; and indicate that the relationship between LVMI and exchanger activity may be specific to the cell type in which exchanger activity is measured.

Adult↗

"Apparent" heart failure: a syndrome caused by renal artery stenoses.

OBJECTIVE: To report on renal artery stenosis presenting as congestive heart failure. DESIGN: Case series. SETTING: Tertiary referral centre. PATIENTS: Nine hypertensive subjects (five male, four female) seen in the blood pressure unit, St George's Hospital, between 1991 and 1997 with clinical signs and symptoms of congestive cardiac failure but without overt coronary or valvar heart disease. Mean (SEM) age was 67 (3) years. Eight patients had renal artery revascularisation with percutaneous angioplasty and one had surgery. RESULTS: Renal revascularisation was followed by a large fall in blood pressure from 191/94 (7/3) to 150/75 (8/5) mm Hg two days after intervention (p < 0.01). There was also a large natriuresis and weight reduction. One week after revascularisation there was a mean loss in weight of 3.8 (0.6) kg. The largest fall in weight was seen in those patients with stenosis in a single functioning kidney. Furthermore, plasma atrial natriuretic factor fell from 120 (28) to 48 (9) pg/ml (p < 0.05; n = 6; normal value = 8.6 (0.8) pg/ml), and serum creatinine fell from 200 (37) to 140 (11) micromol/l (p < 0. 025). The clinical signs and symptoms of heart failure resolved and the diuretics were then withdrawn in all patients. On long term follow up, patients remained free from symptoms and signs of heart failure and the blood pressure was better controlled. CONCLUSIONS: In hypertensive patients with symptoms and signs of congestive heart failure who do not have obvious ischaemic or valvar heart disease, renal artery stenosis should be considered as a possible underlying cause. Relief of the stenosis can result in resolution of the apparent heart failure.

Aged↗

A young woman with chest pain.

A case of a previously fit young woman admitted with chest pain, who was found at coronary angiography to have dissection of the left main stem which extended to the left anterior descending and circumflex coronary arteries, is presented. Emergency coronary artery bypass grafting was performed (vein grafts to the left anterior descending, the diagonal, and circumflex arteries). The patient made an uneventful recovery, and three years after initial presentation she remains free of cardiac symptoms.

Adult↗

Serotonin and heart rate in hypertensive and normotensive subjects.

Plasma and platelet levels of 5-hydroxytryptamine (5 HT) may be altered in essential hypertension. To establish the determinants and correlates of 5 HT in plasma and platelets, we studied 53 untreated subjects with essential hypertension (26 men; 30 whites; mean supine blood pressure 172/101 mm Hg; mean age 49.3 +/- 1.5 years) and 61 normotensive subjects (37 men; 47 whites; mean supine blood pressure 128/78 mm Hg; mean age 42.8 +/- 1.6 years). Plasma and platelet 5 HT were assayed by reverse-phase high performance liquid chromatography with electrochemical detection. No significant difference was found in platelet-poor plasma or platelet 5 HT levels in hypertensive or normotensive subjects (plasma: 43.0 +/- 4.2 and 39.6 +/- 4.4 nmol/L; platelet: 1.65 +/- 1.22 and 1.70 +/- 1.39 nmol/10(9) cells in hypertensive and normotensive subjects, respectively). No significant correlation was found between plasma or platelet 5 HT and systolic or diastolic blood pressure (plasma: r = 0.01 and 0.01 in normotensive subjects and r = 0.01 and -0.14 in hypertensive subjects; platelet: r = 0.12 and 0.13 in normotensive subjects and r = 0.02 and -0.09 in hypertensive subjects). However, plasma 5 HT was associated with supine and standing pulse rates (supine: r = 0.27, p = 0.05 in normotensive subjects and r = 0.54, p < 0.001 in hypertensive subjects; standing: r = 0.19 and r = 0.46, p < 0.001, respectively). Significant relations were also found between platelet 5 HT levels and supine and standing heart rate in the subjects mentioned above (supine: r = 0.28, p = 0.05 in normotensive subjects and r = 0.64, p < 0.001 in hypertensive subjects; standing: r = 0.24 and r = 0.51, p < 0.001, respectively). These associations were stronger in the hypertensive group as a whole, and they held when adjustment was made for differences in age and total blood cholesterol. The present study showed that plasma and platelet 5 HT are not significantly altered in hypertensive subjects. However, plasma and platelet 5 HT levels showed a significant association with supine and standing pulse rate predominantly in hypertensive subjects. This is consistent with experimental evidence of a positive chronotropic effect of 5 HT on perfused hearts and it suggests a possible role of plasma serotonin in the regulation of heart rate.

Adult↗