Prospective validation study of transorbital Doppler ultrasound imaging for the detection of transient cerebral microemboli.

BACKGROUND: Transient cerebral microemboli are independent biomarkers of early risk of ischaemic stroke in acute carotid syndromes. Transcranial Doppler imaging (TCD) through the temporal bone is the standard method for detection of cerebral microemboli, but an acoustic temporal bone window for TCD is not available in around one in seven patients. Transorbital Doppler imaging (TOD) has been used when TCD is not possible. The aim of this study was to validate the use of TOD against TCD for detecting cerebral microemboli. METHODS: The study included patients undergoing elective carotid endarterectomy; all had confirmed temporal and orbital acoustic windows. Subjects gave written informed consent to postoperative TCD and TOD monitoring, which was performed simultaneously for 30 min by two vascular scientists. RESULTS: The study included 100 patients (mean(s.e.m.) age 72(1) years; 65 men). Microemboli were detected by one or both methods in 40·0 per cent of patients: by TOD and TCD in 24 patients, by TOD alone in ten and by TCD alone in six. For detecting microemboli, TOD had a sensitivity of 80·0 per cent, specificity of 86·1 per cent, positive predictive value of 71·6 per cent and negative predictive value of 91·2 per cent. Bland-Altman analysis revealed no significant bias (bias 0·11 (95 per cent c.i. -0·52 to 0·74) microemboli; P = 0·810) with upper and lower limits of agreement of +6 and -6 microemboli. CONCLUSION: TOD appears a valid alternative to TCD for detecting microembolic signals in patients with no suitable temporal acoustic window.

Management of hypertension in peripheral arterial disease: does the choice of drugs matter?

Cardiovascular disease and death are major life-threatening problems in patients with atheromatous peripheral arterial disease (PAD). This review focuses on management of hypertension in the context of cardiovascular risk in patients with PAD. PAD is underdiagnosed and hypertension in PAD is often poorly managed. Current evidence supports a low threshold for blood pressure treatment in PAD and intensive blood pressure control to reduce the high risk of cardiovascular disease and death in patients with PAD. Optimal treatment targets should be <140/85 mmHg, with the lower target of <130/80 mmHg in the presence of diabetes mellitus or chronic renal disease. Class-specific selection of anti-hypertensive treatments in PAD should be based on caution in relation to co-existing renovascular disease and indications and contraindications based on other significant co-morbidity. There is a pressing need for primary end-point studies targeted specifically at patients with PAD. In particular, prospective studies in PAD are needed to obtain evidence for benefits from specific blood pressure classes of treatment as well as the optimal blood pressure treatment target level. These studies should consider impact in PAD of different demographic, risk factor, and co-morbidity profiles.

Rarefaction of skin capillaries in normotensive offspring of individuals with essential hypertension.

BACKGROUND: Rarefaction of skin capillaries in people with intermittent borderline essential hypertension suggests a primary or an early abnormality that may antedate the onset of sustained hypertension. OBJECTIVE: To compare skin capillary density in subjects with and without a family history of essential hypertension. SUBJECTS: 21 normotensive individuals, one or both of whose parents had essential hypertension (mean age 39.3 years; blood pressure 124/79 mm Hg); 21 normotensive controls with no family history of hypertension (age 46.3 years; blood pressure 124/78 mm Hg). METHODS: The skin of the dorsum of the fingers was examined by intravital capillary microscopy before and after venous congestion at 60 mm Hg for two minutes. RESULTS: By analysis of variance, both baseline and maximum skin capillary density were lower in subjects with a family history of essential hypertension than in those with no family history (baseline: 67 v 79 capillaries per field, p = 0.008; maximum: 74 v 93 capillaries per field, p < 0.0005). CONCLUSIONS: Capillary rarefaction in essential hypertension may occur before the increase in blood pressure and could, at least in part, reflect a primary rather than a secondary abnormality.

Plasma brain natriuretic peptide as a predictor of haemodynamically significant patent ductus arteriosus in preterm infants.

Patent ductus arteriosus (PDA) is an important cause of morbidity in extremely preterm infants. As increased plasma brain natriuretic peptide (BNP) is a common feature of adult cardiac disease, we investigated the value of plasma BNP concentration as a predictor of haemodynamically significant PDA in very preterm infants. We studied 18 preterm infants (12 male) of median gestational age 30 weeks (range 24-34), median birth weight 1.46 kg (0.54-2.13) and 11 healthy term controls. Plasma BNP levels were measured by double-antibody radioimmunoassay on days 3, 5 and 7 of life, and an echocardiogram was performed on day 7. Six infants of median gestation 26 weeks (26-30), median birth weight 0.92 kg (0.54-1.04) had PDA proven by echocardiography on day 7. BNP concentrations (pg/ml) on day 3 were significantly higher in these infants than in the remaining twelve [median 2012 (786-2759) versus 42 (7-704), P<0.001]. In four infants PDA was treated successfully (one surgically, three with non-steroidal anti-inflammatory drugs). Two had haemodynamically insignificant closing ducts. In these infants with therapeutic or spontaneous resolution of a PDA, plasma BNP fell to normal values [median after treatment 9 pg/ml (8-27)]. Early measurement of plasma BNP in the first few days of life is a useful method for predicting those preterm infants who may require intervention for PDA.