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Biomedical subjects

A Haapanen

Publications and source records attributed to A Haapanen.

At least 19 recordsLinked to original sources
PubMed2000

Increased arterial intima-media thickness and in vivo LDL oxidation in young men with borderline hypertension.

We used borderline hypertension as a model for prehypertension to examine the early influences of elevated blood pressure on subclinical atherosclerosis, lipoprotein oxidation, and cardiac adaptation. Healthy men (age 37+/-4 years) were classified prospectively into 2 groups on the basis of having either borderline hypertension (systolic 130 to 140 mm Hg or diastolic 85 to 89 mm Hg, n=16) or normal (<130/85 mm Hg, n=22) blood pressure values during the previous 2 years. The groups were matched for age, body size, and serum cholesterol levels. High-resolution ultrasound was used to measure intima-media thickness (IMT) of the carotid and brachial arteries, cardiac dimensions, and brachial artery endothelial function. Baseline low-density lipoprotein (LDL)-diene conjugation was measured as an estimate of in vivo LDL oxidation (ox-LDL). Compared with normotensive controls, men with borderline hypertension had higher IMT of the carotid artery (0.58+/-0.06 versus 0.75+/-0.07 mm, P<0.001) and IMT of the brachial artery (0.45+/-0.05 versus 0.57+/-0.07 mm, P<0.001), and increased levels of ox-LDL (29+/-9 versus 47+/-17 mol/L, P<0.001), but similar endothelial function. Left ventricular mass was similar in both groups, but there were significant differences in left ventricular geometry. In multivariate analyses, the predictors of carotid IMT were 24-hour systolic blood pressure (P<0.001) and ox-LDL (P=0.10). The current study demonstrates evidence of increased subclinical atherosclerosis and ox-LDL in borderline hypertension. These results are consistent with the idea that enhanced ox-LDL may be one of the pathophysiological events related to development of atherosclerosis in men with borderline elevated blood pressure.

Adult↗
PubMed1997

The peripheral resistance in arteries of legs is inversely proportional to the severity of chronic venous insufficiency.

There are conflicting reports in the literature about the existence of arteriovenous shunting in legs with chronic venous insufficiency. Using duplex scanning, we have earlier shown that there is lowered peripheral resistance in the arteries of legs with venous ulcer together with premature venous filling in angiography. In the present study we investigated the peripheral resistance in the arteries of 16 legs with chronic venous insufficiency without present ulcer. We compared the results with those obtained from 12 healthy legs and from 18 legs with venous ulcer. There was a highly significant inverse correlation between the severity of chronic venous insufficiency and the peripheral resistance in the popliteal, the dorsal pedal and the posterior tibial arteries (p < 0.001). These results suggest that there is arteriovenous shunting in legs with chronic venous insufficiency and that this phenomenon correlates with the degree of chronic venous insufficiency.

Arteries↗
PubMed1996

Dynamic Gd-DTPA-enhanced MR imaging of the kidney: comparison between T1- and T2-weighted sequences.

OBJECTIVE: To determine whether T1- or T2-weighted sequences are more informative and practical in dynamic Gd-DTPA-enhanced MR imaging for the evaluation of renal blood flow and function. MATERIALS AND METHODS: Dynamic Gd-DTPA-enhanced MR imaging of the kidney was performed in 7 patients by either T1-weighted TurboFLASH (TR/TE/TI/FA = 9/4/27/8) or T2-weighted FLASH (TR/TE/FA = 32/22/10) sequences for comparison of the enhancement pattern. None of the subjects had a suspicion of renal dysfunction from laboratory data, and the absence of renal artery stenosis was confirmed by conventional angiography. RESULTS: During the early phase, the marked signal increase in T1-weighted imaging in the renal cortex corresponded to a similar marked decrease in signal intensity in T2-weighted imaging. During the middle and late phases, the medulla was dramatically decreased in intensity on the T2-weighted imaging resulting in a good contrast between the cortex and medulla. CONCLUSION: Both sequences may provide almost similar information about the renal cortical blood flow. However, T2-weighted dynamic MR imaging may be more informative than T1-weighted dynamic MR imaging about the concentrating ability in the renal medulla. A high concentration of Gd-DTPA in the tubular structure was suspected to cause a dramatic decrease in intensity in the medulla in T2-weighted imaging.

Adult↗
PubMed1994

Myocardial viability: fluorine-18-deoxyglucose positron emission tomography in prediction of wall motion recovery after revascularization.

To assess the value of positron emission tomography (PET) imaging with fluorine-18-deoxyglucose ([18F]FDG) in predicting cardiac wall motion recovery after revascularization, 48 consecutive patients with previous myocardial infarction were studied. The normalized [18F]FDG uptake at rest was assessed semiquantitatively and compared to perfusion at rest as studied by SPECT imaging. Wall motion was analyzed with echocardiography before and after revascularization. Wall motion recovery occurred in 27 (30%) of the revascularized 90 dysfunctional segments. Preserved [18F]FDG uptake (mean +/- 2 SD) was commonly found in dysfunctional segments, but only 54% of these segments recovered after revascularization. Subnormal [18F]FDG uptake identified accurately the segments with no potential to recover (predictive value 100%). By using an optimized threshold value for normalized [18F]FDG uptake, the sensitivity of 85% and specificity of 84% to predict functional recovery were reached simultaneously. However, in the segments with moderately or severely reduced perfusion at rest, the diagnostic accuracy of [18F]FDG uptake for viability was 100%. The results of this study show that the presence of viable tissue indicated by preserved [18F]FDG uptake does not inevitably imply functional recovery after revascularization. However, acceptable diagnostic accuracy for viability might be reached by [18F]FDG alone, providing that appropriate uptake limits are used. The combined evaluation of [18F]FDG uptake and perfusion enables precise assessment of myocardial viability.

Angioplasty, Balloon, Coronary↗
PubMed1994

Lowered peripheral resistance in arteries of legs with venous ulcer.

In the literature there is disagreement concerning the existence of arteriovenous shunting in legs with venous ulcer(s). The aim of this study was to find out if there are differences in resistance in the arteries of ulcer legs and non-ulcer legs and if it is possible to investigate this with a non-invasive Doppler method. Eleven patients, aged 34-87 years, with venous ulcer only in one leg, were investigated using angiography and duplex scanning. Angiography showed premature venous filling and Doppler examination showed lowered peripheral resistance in the arteries of every ulcer leg. Lowered peripheral resistance was found only in one non-ulcer leg, which, however also had signs of venous stasis. Our results clearly show that there is lowered peripheral resistance in arteries of legs with venous stasis. The possible significance of this phenomenon in the pathogenesis of venous leg ulcer is discussed.

Adult↗
PubMed1993

The value of quantitative analysis of glucose utilization in detection of myocardial viability by PET.

To study whether absolute quantitation of regional myocardial glucose utilization (rMGU) enhances detection of myocardial viability, 70 nondiabetic patients with prior myocardial infarction and angiographically confirmed coronary artery disease were studied with [18F]FDG PET after oral glucose loading. Forty-eight patients were also revascularized and underwent echocardiography after revascularization to detect wall motion recovery. The rMGU was calculated in eight myocardial segments in each patient and the results were compared to normalized (relative) [18F]FDG uptake values. In normal segments (n = 225), rMGU was 56 +/- 18 mumole/min/100 g (mean +/- s.d.) and relative [18F]FDG uptake 97% +/- 12%. The interindividual variation of rMGU in normal myocardium was greater than the intraindividual variation (s.d. 31% versus 11%). The respective values for relative [18F]FDG uptake were 9% and 10%. Both rMGU and [18F]FDG uptake were significantly reduced in segments with scarring observed visually during bypass surgery (29 +/- 19 mumole/min/100 g and 45% +/- 22%, n = 26). The rMGU and [18F]FDG uptake were higher in segments that recovered after revascularization (53 +/- 17 mumole/min/100/g and 110% +/- 21%, n = 27) than in those that did not (37 +/- 20 mumole/min/100 g and 65% +/- 24%, n = 63). However, due to larger variability of rMGU values, normalized [18F]FDG uptake was superior to rMGU in separating normal and scar segments as well as in predicting wall motion recovery. We conclude that rMGU variability is notable and is caused mainly by variations between patients. Interindividual variation is reduced by normalization, which results in more accurate assessment of myocardial viability. Thus, static imaging and semiquantitative analysis are sufficient for the clinical assessment of myocardial viability.

Coronary Angiography↗
PubMed1992

Euglycemic hyperinsulinemic clamp and oral glucose load in stimulating myocardial glucose utilization during positron emission tomography.

To enable assessment of myocardial viability, myocardial glucose utilization has commonly been stimulated by oral glucose loading. To compare the effects of glucose loading and insulin and glucose infusion (insulin clamp) on PET fluorodeoxyglucose ([18F]FDG) myocardial scan image quality and regional myocardial glucose utilization rate (rMGU), eight patients with angiographically documented coronary artery disease and previous myocardial Q-wave infarction were studied twice, once during insulin clamp and once 1 hr after oral glucose loading. The rMGU rates were derived by graphic Patlak analysis in 33 normal, 10 scar and 6 "hot spot" myocardial segments. Infusion of insulin and glucose gave stable plasma-glucose and serum-insulin levels during imaging. In contrast, glucose loading caused marked changes in plasma-glucose and insulin concentrations. The image quality was clearly superior and the fractional utilization rates of [18F]FDG were twice as high during insulin clamp than after glucose loading (p less than 0.0001). Due to the higher plasma-glucose levels after glucose loading, the calculated rMGU in normal, scar and hot spot myocardial segments was comparable between the two protocols. The insulin clamp technique makes it possible to adjust and maintain a metabolic steady state during the PET study. It does not alter [18F]FDG uptake patterns in different myocardial areas when compared to the standard glucose loading protocol, but this technique results in superior image quality and permits the use of smaller [18F] FDG patient doses.

Administration, Oral↗
PubMed1991

Measurement of intima-media thickness of common carotid arteries with high-resolution B-mode ultrasonography: inter- and intra-observer variability.

High-resolution B-mode ultrasonography enables quantitative measurement of the thickness of the intima-media layer of superficial large arteries noninvasively. We investigated the inter- and intra-observer variability of this measurement in the common carotid arteries in 10 randomly selected men. The maximal right and left carotid intima-media thickness (IMT) was measured with calipers during the scanning from frozen images by four observers in a blinded fashion. Three observers also repeated the scanning and the measurements twice with a week's intervals, with no knowledge of the previous readings. The inter-observer coefficient of variation (CV) was 10.5%. The intra-observer CV (mean of right and left CCA) was 5.4-5.8% for the three observers who carried out the measurements three times. The mean absolute difference between the first and third measurement was 0.087 mm. The intra-observer variation accounted for only 4% of the total measurement variability, 96% being attributable to inter-observer variation. These data show that most of the measurement variability in ultrasonographic B-mode IMT measurements is due to differences between observers, whereas the within-observer variability over time appears proportionately very small.

Analysis of Variance↗
PubMed1989

Late carotid restenosis: aetiologic factors for recurrent carotid artery stenosis during long-term follow-up.

During a fourteen-year-period 257 patients underwent carotid endarterectomy in an unselected population of 700,000 inhabitants. The incidence of haemodynamically significant restenosis was 13.5% in 133 vessels in 116 patients studied by duplex scanning 28 to 209 months following carotid endarterectomy. The most striking differences between patent and restenosed cases were in serum cholesterol, triglyceride and HDL-cholesterol levels. The patients with a long-term low cholesterol (less than 6.5 mmol/l), low triglyceride (less than 1.42 mmol/l) and high HDL cholesterol (greater than 1.0 mmol/l) levels had significantly less high grade restenosis (P less than 0.05). Apolipoprotein A-I and B had no significant effect, but if the lowest limit of normal apolipoprotein A-I level was considered as 1.27 g/l the difference was significant. The frequency of a high-grade restenosis in patients with diabetes mellitus and coronary heart disease was not significantly increased, but supports the view that these are risk factors in the development of atherosclerotic changes in an operated carotid artery. The incidence of recurrent stenosis appears to be unrelated to hypertension, claudication, obesity, smoking, operative factors or to the indication for surgery. Men were more prone than women to get a high-grade restenosis. Postoperative treatment with acetylsalicylic acid was most effective, the incidence was only half of that expected, whereas the anticoagulants or a combination of acetylsalicylic acid and dipyridamole were of no benefit. Haematocrit, RBC, platelet count and thrombocrit were contradictory.

Adult↗
PubMed1989

Carotid arteriosclerosis in identical twins discordant for cigarette smoking.

From a nationwide twin panel, identical twin pairs with highest discordance in cigarette smoking were selected for a study of arteriosclerosis (49 pairs with a mean age of 52 years). Smoking history was obtained in 1975, 1981, and 1986. The mean life-long smoking dose of the smoking cotwins was 20 package-years. The smoking and nonsmoking cotwins had similar systolic and diastolic blood pressures, total plasma cholesterol level, body mass index, and some psychosocial factors; the only difference was found in use of alcohol, which was greater among smoking cotwins. Duplex sonography of carotid arteries was performed. Carotid artery stenoses (narrowing of area of the lumen with 15-60%) were found in nine pairs: in nine smoking twins and in two of their nonsmoking cotwins (p = 0.036). The total area of carotid plaques was 3.2 times larger in smoking cotwins (p less than 0.001). The thickness of the inner layer of carotid arteries was more marked in smoking cotwins (p less than 0.001). The size of plaques and the degree of inner layer thickening correlated with the dose of smoking (NS). The association of smoking with carotid arteriosclerosis was highly significant even after the adjustment for age, total plasma cholesterol level, diastolic blood pressure, and body mass index in multiple logistic regression analyses.

Carotid Arteries↗
PubMed1988

Vasoactive and atherogenic effects of cigarette smoking: a study of monozygotic twins discordant for smoking.

The mechanism by which atherosclerotic disease is induced by cigarette smoking has not yet been identified unequivocally. Chronic cigarette smoking and the generation of vasoactive prostanoids and the size of carotid atherosclerotic plaques were studied in nine pairs of identical male twins discordant for smoking for over 20 years. The urinary excretion of 2,3-dinor-thromboxane B2 (thromboxane B2 metabolite) of the smoking twin was significantly higher (on average 1.8 times higher) in every pair and that of 2,3-dinor-6-keto-prostaglandin F1 alpha (prostacyclin metabolite) was significantly higher (on average 1.3 times higher) in eight of the nine pairs. The ratio of excretion of these metabolites was significantly higher, being 4.0 (95% confidence interval 2.7 to 5.4) among the smokers compared with 2.9 (2.1 to 3.8) among the non-smokers, thus favouring a mechanism of vasoconstriction. Excretion of the thromboxane B2 metabolite was related to the urinary concentrations of nicotine metabolites. Atherosclerotic plaques detected by ultrasonography in the carotid arteries were significantly larger among smokers but did not correlate with the urinary excretion of prostacyclin and thromboxane B2 metabolites or intensity of smoking. Smoking was concluded to induce activation of platelets by an effect mediated by nicotine. The increased prostacyclin production, on the other hand, suggested a compensatory mechanism for the general vasoconstrictive properties of cigarette smoking.

6-Ketoprostaglandin F1 alpha↗
PubMed1984

Percutaneous dilatation of lower leg arteries.

Percutaneous transluminal angioplasty was introduced in the X-ray department of the Central Hospital of Etel ä- Pohjanmaa in 1981 for the treatment of arteriosclerosis of the leg. The first year material consisted of 43 patients. Of the 45 lesions treated 16 were iliac stenoses, 12 femoropopliteal stenoses, 16 femoropopliteal occlusions, and one occlusion of the deep femoral artery. In 20 cases, angioplasty was performed for limb salvage from amputation, in 23 because of claudication. Technical success was achieved in every stenosis and in 10 out of the 16 femoropopliteal occlusions (63 per cent). One year cumulative patency rate was 81% in iliac stenoses, 66% in femoropopliteal stenoses, and 50% in femoropopliteal occlusions. Diabetes had an adverse effect on the results. Excluding patients with diabetes, the corresponding figures were 88%, 89%, and 60% respectively.

Aged↗