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Biomedical subjects

D L Clement

Publications and source records attributed to D L Clement.

At least 19 recordsLinked to original sources
PubMed1992

Comparison of lisinopril and nitrendipine on the pulsatility index in mild essential arterial hypertension.

A double-blind, randomized crossover study was performed in 21 patients with essential arterial hypertension. Nitrendipine 20 mg o.d. and lisinopril 20 mg o.d. were given in a randomized order during a period of each 8 weeks. Nitrendipine and lisinopril decreased systolic and mean arterial blood pressure to a similar level without a significant increase in heart rate. The mean diastolic blood pressure was smaller with the lisinopril treatment than with the nitrendipine treatment. The blood pressure decrease was maintained in the sitting and standing position. Furthermore, only nitrendipine decreased the pulsatility index at the tibial posterior arteries, while lisinopril did not influence it significantly. This finding means that mechanisms other than the blood-pressure lowering effect are involved in the decrease of the pulsatility index.

Adult↗
PubMed1992

Venous responses to rhythmic exercise in contralateral forearm and calf.

Ten normal healthy subjects performed a rhythmic handgrip at 30% MVC (maximal voluntary contraction) with and without arterial occlusion of the same limb. Contralateral forearm and calf venous capacitance were simultaneously measured by venous occlusion plethysmography. During rhythmic handgrip at 30% MVC contralateral venous capacitance decreased by -7.17% in the forearm and by -5.14% in the calf. With arterial occlusion the decreases in venous capacitance were even more pronounced: contralateral forearm -14.4% and calf -13.1%. In a second set of experiments (n = 5) rhythmic handgrip at 30% MVC with arrest of the forearm circulation 5 s prior to the cessation of contraction was applied to examine the influence of chemically sensitive metaboreceptors per se on the evoked limb venoconstriction. During the postexercise arterial occlusion forearm venous volume decreased further to -30.6% whereas calf venous volume increased slightly but remained below the control value. After the cessation of the arterial occlusion both forearm and calf capacitance returned to baseline values. Thus, this study provided evidence that as well as a chemically generated reflex arising from the working muscle, central command was found to be involved in the increase in venomotor tone in the nonexercising limbs during rhythmic handgrip at 30% MVC.

Adult↗
PubMed1992

Blood pressure load determines left ventricular mass in essential hypertension.

In a series of 35 newly diagnosed, previously untreated patients (mean age 46 years) with mild to moderate essential hypertension, office blood pressure measurements, 24-hour ambulatory blood pressure monitoring, and determination of left ventricular mass index by echocardiography according to the formula of Devereux were performed. We aimed at correlating left ventricular mass index with systolic and diastolic office blood pressure, mean 24-hour systolic and mean 24-hour diastolic blood pressure, systolic and diastolic load. Left ventricular mass index did not correlate with office systolic and office diastolic blood pressure. On the contrary, all correlations with ambulatory blood pressure parameters and left ventricular mass index turned out to be significant (mean 24-hour systolic blood pressure: r = 0.344, P = 0.026; systolic load: r = 0.408, P = 0.020; mean 24-hour diastolic blood pressure: r = 0.490, P = 0.004; diastolic load: r = 0.504, P = 0.003). These results clearly demonstrate that ambulatory blood pressure determinants but not the office blood pressure parameters are well correlated with left ventricular mass index in mild to moderate essential hypertension. Blood pressure load is as important as mean 24-hour blood pressure in this regard.

Adult↗
PubMed1992

Transoesophageal echo-Doppler in patients suspected of a cardiac source of peripheral emboli.

The initial results of a controlled and partly blinded study aimed at evaluating the accuracy of transoesophageal echo-Doppler in detecting cardiac sources of peripheral emboli are reported. A total of 120 consecutive patients suspected of acute embolic events were entered. After completion of all investigations, the patients were classified into three groups: patients who had definitely not suffered an embolic event (controls; n = 56); patients in whom the differentiation between local thrombosis, embolic event originating from a diseased infarct-related artery or embolic event from a cardiac source was not possible (questionable cases; n = 24) and patients in whom a cardiac source of a definite embolic event was highly suspected (cardiac emboli; n = 40). Isolated interatrial septum anomaly and mitral valve prolapse were as frequent in the control group as in the embolism group. Transoesophageal echo-Doppler had a sensitivity of 83% and a specificity of 86% in correctly assigning a patient to the cardiac embolism group or to the control group. The positive and negative predictive values were 80% and 87% respectively. It is concluded that transoesophageal echo-Doppler is highly sensitive but is also specific in demonstrating cardiac sources of peripheral emboli.

Adult↗
PubMed1992

Medical treatment of peripheral vascular disease: good or bad?

The majority of patients with intermittent claudication are treated conservatively; smoking must be stopped and exercise therapy commenced. There are various classes of drugs that are widely prescribed for the treatment of peripheral vascular disease. In this editorial the medical treatment of peripheral vascular disease is claimed to achieve at least one of three goals: (1) improvement of the functional capability; (2) inhibition of the progression of the atherosclerotic and anatomical lesions; (3) reduction of the cardiac and cerebrovascular morbidity and mortality. Guidelines are given for well controlled trials for newly developed drugs for the treatment of peripheral vascular disease in the future.

Arterial Occlusive Diseases↗
PubMed1992

Impaired microcirculation in mild-to-moderate essential arterial hypertension.

OBJECTIVE: The aim of this study was to correlate capillary morphology and erythrocyte velocity to blood pressure in mild-to-moderate essential arterial hypertension. DESIGN: Ambulatory blood pressure measurement may provide more precise information about a patient's mean blood pressure than office measurements. METHODS: Fifteen patients with recently diagnosed, previously untreated mild-to-moderate essential hypertension underwent 24-h ambulatory blood pressure recording and a capillaroscopic examination of finger microcirculation. Erythrocyte velocity was determined by the flying spot technique. RESULTS: Both mean 24-h ambulatory systolic blood pressure (SBP) and mean 24-h ambulatory diastolic blood pressure (DBP) were significantly inversely correlated with capillary erythrocyte velocity. However, the correlation between erythrocyte velocity and office SBP and office DBP was less significant. Capillary length was related to 24-h ambulatory DBP but not to office DBP. Capillary number was not related to any blood pressure parameter. CONCLUSIONS: These results indicate that, in patients with mild-to-moderate essential hypertension, erythrocyte velocity is significantly lower than for matched controls. It is also inversely related to mean 24-h ambulatory SBP and 24-h ambulatory DBP.

Blood Flow Velocity↗
PubMed1992

Examination of Raynaud's phenomenon in traumatic vasospastic disorders.

Certain types of occupation-related vibrations can cause traumatic vasospastic disorders. Findings from clinical examination are often normal at the office consultation. Measurements of finger blood flow using plethysmography while the local ambient temperature is changed can give important information about the severity of traumatic vasospastic disorder and the concomitant disability. This technique can also be used for follow-up of the finger blood flow after withdrawal from vibrations.

Adult↗
PubMed1992

Acute myocardial infarction size and myoglobin release into serum.

The kinetics of myoglobin release after acute myocardial infarction were studied. Various algorithms for calculation of infarct size, based on immunonephelometric determination of myoglobin and cumulative myoglobin release into the circulation were compared. The cumulative myoglobin release and maximal serum myoglobin concentration were compared with various measures of infarct size: cumulative release of creatine kinase, electrocardiographic changes, and left ventricular ejection fraction. After acute myocardial infarction, time to peak for myoglobin in serum was correlated with time to peak for creatine kinase (r = 0.645). On average, the myoglobin concentration peaked 8.8 h earlier than creatine kinase activity. The rate of elimination of myoglobin showed a large variation (0.041-0.628 h-1) and was not correlated with the elimination rate of creatine kinase. The elimination rate of myoglobin after acute myocardial infarction was shown to depend on the patient's age and infarct size. The elimination constant of myoglobin is preferably estimated on an individual basis in large and complicated infarctions. Cumulative myoglobin release correlated with algorithms based on the cumulative release of creatine kinase (r = 0.622) and its isoenzyme MB (r = 0.660), and to a lesser extent with the residual left ventricular ejection fraction (r = 0.513) and the sum of ST-segment deviations on electrocardiography (r = 0.469). Maximal myoglobin values in serum correlated moderately with the calculated infarct size (r = 0.488; based on creatine kinase-MB) and electrocardiographic changes (r = 0.554). In combination with fast immunological methods for myoglobin determination, myoglobin peak height offers the advantage of providing reliable results within 12 h after onset of symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Value of ambulatory blood pressure recordings.

In the present paper, the value of ambulatory blood pressure recordings is discussed. Such recordings can be very helpful in the management of high and low blood pressure. The fact that more readings are obtained and that they are made in normal life conditions are the strongest arguments in favour of those recordings. Whether ambulatory recordings predict long term prognosis better than office blood pressure is still open for discussion; the long term European study OvA should help clarifying this important question. Data coming from these techniques are especially useful when conflicting elements are present such as high pressure with no organ damage or blood pressure resistant to all drugs and side effects occurring with even minor doses of antihypertensive drugs. Short term episodes of high or low pressure are best documented with ambulatory blood pressure recordings and this holds particularly true in patients with arterial hypotension. Finally several research aspects can be approached by ambulatory recordings of pressure such as the study of pharmacokinetics of drugs and analysis of blood pressure variability.

Adrenergic beta-Antagonists↗
PubMed1992

Long-term (2-year) isradipine data in the treatment of mild-to-moderate hypertension.

At the end of a short-term (3-month) study of antihypertensive treatment of mild-to-moderate hypertension, 141 of the 200 study patients continued into a 2-year follow-up of isradipine as monotherapy or in combination with other antihypertensive agents. Although all 141 patients completed the first year, only 102 completed the study. Twenty-four patients dropped out: 2 with flushing; 1 each with arrhythmia, edema, angina, and headache; 12 who were noncompliant; 2 with disease unrelated to the study drug; and 4 for reasons unknown. Before the follow-up, 70% of the 141 patients were taking isradipine; after 2 years, 63% were still taking isradipine as monotherapy. During the follow-up study, the blood pressure remained stable (142.9/86.8 mm Hg after 3 months, and 142.9/86.2 mm Hg after 2 years), whereas the normalization rate was only slightly changed (73 vs. 75.2%). The incidence of reported adverse events decreased with time. At the end of the short-term study, 44.7% of patients had reported one or more adverse events; after 2 years of treatment, only 14.4% reported adverse events. Two patients had ECG signs of left ventricular hypertrophy: one showed no relevant changes while the other presented clear signs of regression. No clinically relevant laboratory abnormalities were noted during the study. In conclusion, isradipine is effective, well tolerated and safe in the long-term treatment of mild-to-moderate hypertension.

Calcium Channel Blockers↗
PubMed1991

Influence of the arterial blood pressure and nonhemodynamic factors on left ventricular hypertrophy in moderate essential hypertension.

In a group of 36 untreated patients with mild to moderate essential hypertension (office systolic and diastolic blood pressures (BPs) 160 +/- 3.4 and 102 +/- 1.5 mm Hg, respectively), a 24-hour ambulatory BP monitoring and determination of left ventricular (LV) mass index according to the formula of Devereux were performed. After an overnight fast, blood samples were taken for the determination of serum aldosterone, plasma renin activity and serum parathyroid hormone. Urinary catecholamines were sampled for 24 hours. LV mass index (143.7 +/- 8 g/m2) did not correlate significantly either with office systolic or diastolic BP. The correlation of LV mass index with mean 24-hour systolic BP (145 +/- 3 mm Hg) was statistically significant: r = 0.395, p = 0.026. However, the best correlation was obtained with mean 24-hour diastolic BP (90 +/- 3 mm Hg) with r = 0.500 (p = 0.004). Urinary catecholamines were not correlated with LV mass index. LV mass index correlated significantly with plasma renin activity (r = 0.346, p = 0.050), and aldosterone (r = 0.559, p = 0.001). There was a very significant correlation between LV mass index and parathyroid hormone (r = 0.719, p = 0.00001) even after adjustment for mean 24-hour systolic and diastolic BPs. These results clearly demonstrate that ambulatory BP determinants but not office BP parameters are well correlated with LV hypertrophy in essential hypertension. Nonhemodynamic factors are important determinants of LV mass as well. Besides the renin-angiotensin-aldosterone system, parathyroid hormone appears to play an important role in cardiac hypertrophy.

Adult↗
PubMed1991

Influence of nebivolol on the cardiovascular hemodynamics during postural changes and isometric exercise.

Nebivolol (R67555), a drug with beta 1 receptor antagonizing properties, was administered once daily (5 mg) for 7 days in 10 healthy volunteers. The hemodynamic parameters were measured noninvasively during postural changes (supine, sitting, standing) and during isometric handgrip at 50% maximal voluntary contraction, before and 3, 8, and 23 hours after the first nebivolol intake of 5 mg; the same measurements were done 23 hours after the last intake. Nebivolol lowered arterial blood pressure acutely and chronically due to a decrease in heart rate and cardiac output. The stroke volume seemed to be preserved, while the total peripheral vascular resistance did not change. Nebivolol did not change the orthostatic responses, except that the absolute value was lowered. Nebivolol was unable to prevent the blood pressure increase during isometric handgrip. However, this blood pressure increase was obtained by an increase in the total peripheral vascular resistance and not by an increase in the cardiac output, as observed during control measurements before nebivolol intake.

Adrenergic beta-Antagonists↗
PubMed1991

Assessment of myocardial ischemia by 12-lead electrocardiography and Frank vector system during coronary angioplasty: value of a new orthogonal lead system for quantitative ST segment monitoring.

The optimal number and placement of electrocardiographic (ECG) leads to detect myocardial ischemia induced by coronary balloon inflation was assessed by analyzing ST segment changes in the standard 12-lead ECG and Frank X, Y, Z leads at 90-s intervals during 34 consecutive coronary angioplasty procedures. Mean occlusion time during angioplasty was 218 +/- 65 s. Myocardial ischemia, defined as transient angina or ST segment deviation greater than or equal to 1 mm in at least one lead, occurred in 33 (97%) of the 34 procedures. The most sensitive single leads (V2 or V3) detected 17 (51%) of 33 ischemic episodes. The best dual-lead combinations (leads V2 and V5, leads a VF and V3 and leads V3 and Y) increased the sensitivity of 69% (23 of 33). The three-lead combination V2, V5, Y had the highest detecting power (78% [26 of 33]). The X, Y, Z leads by themselves had a sensitivity of only 60% (20 of 33). From this proposed orthogonal lead system (V2, V5, Y), which combines anteroposterior (V2), left to right (V5) and inferosuperior (Y) forces, the spatial ST vector magnitude was calculated and monitored during balloon inflations. A good correlation was observed between this ST vector magnitude and the sum of ST deviations on the standard ECG (r = 0.940, p less than 0.00001), and these data were reproducible over sequential balloon inflations. The results of the study suggest that this orthogonal lead system is of considerable value in the detection and quantification of acute myocardial ischemia and, in this respect, is more useful than the Frank orthogonal vector system.

Adult↗
PubMed1991

Diagnostic approach to patients with primary hyperaldosteronism.

We report the case of a 38-year-old patient with primary hyperaldosteronism. The diagnosis was made by the demonstration of a non-suppressible high aldosterone level in association with a hypokalemia, an inappropriate kaliuresis and low plasma renin activity. As the choice of the therapeutic approach is dictated by the subtype, further investigation was needed. Using a number of hormonal studies and noninvasive imaging techniques, we could establish the diagnosis of adrenocortical adenoma. Histological examination confirmed our diagnosis. We further discuss briefly the characteristics of the four subtypes of primary hyperaldosteronism and show that the used biochemical markers and imaging techniques are able to differentiate them.

Adenoma↗
PubMed1991

Effects of isradipine on peripheral hemodynamic reflex responses in mild-to-moderate essential hypertension.

In a randomized double-blind, placebo-controlled, crossover study of isradipine (5 mg twice daily), effects on peripheral hemodynamic reflex responses were studied in nine patients (mean age 48 years) at baseline and after six weeks of active treatment. Assessments included vital signs, resting blood flow in the calf and finger (using an electrocardiograph-triggered venous occlusion plethysmograph), reflex responses during isometric exercise and cold pressor resistance, and venous capacitance in the forearm and calf. Isradipine lowered systolic and diastolic blood pressure as well as mean arterial pressure in patients with mild-to-moderate essential hypertension without reflex tachycardia or venoconstriction. All of the reflex responses studied were attenuated. It is concluded that vasodilatation of the peripheral circulation induced by isradipine contributes partially to the blood pressure-lowering effect.

Adult↗