Angiology

Forty-nine patients, with ages ranging from eighteen to seventy years and with mild to moderate primary hypertension (sitting diastolic blood pressure of > 95 mmgH and < 115 mmHg) were randomized into a twenty-one-week, double-blind, prospective study to determine the effects of monotherapy of nifedipine GITS (gastrointestinal therapeutic system) versus atenolol on serum lipids, lipid subfractions, apolipoproteins, (apo), and blood pressure (BP). Nifedipine GITS and atenolol significantly reduced blood pressure, but nifedipine GITS reduced sitting and standing systolic BP significantly more than atenolol (p = .001). Sitting and standing heart rate decreased significantly (p = 0.001) during atenolol therapy but did not change significantly during nifedipine GITS therapy. Atenolol increased weight (mean change + 2.2 lb; p = 0.011), but nifedipine GITS decreased weight (mean change - 2.4 lb; p = 0.07).

Nifedipine GITS had a more favorable effect on the lipid profile. High density lipoprotein cholesterol (HDL-C) and HDL₂ subfractions were increased significantly (p = .001) as were apo A1 (p = 0.037) and apo A₂ (p = 0.025). Nifedipine GITS increased HDL₃ (NS), reduced triglycerides (TG) (NS), and had no significant effect on total cholesterol (TC) low density lipoprotein cholesterol (LDL-C) and apo B.

Atenolol significantly increased serum total cholesterol (p = 0.039) and HDL-C and HDL₂ (p = 0.049 and 0.048 respectively). Atenolol increased TG (NS) and apo B (NS) with little change in apo A1 and apo A2. It is concluded that nifedipine GITS had equal or better antihypertensive efficacy than atenolol and had a more favorable effect on the lipid profile. These effects may offer advantages in reducing CHD risk.

The effects of L-dopa on blood pressure, heart rate, plasma renin activity, norepinephrine, epinephrine and prolactin were studied in a randomized single-blind trial in 36 patients with essential hypertension. In response to L-dopa, 250 mg administered orally, the blood pressure decreased significantly as compared with the results of placebo treatment. The heart rate and plasma norepinephrine and epinephrine were unchanged. The plasma renin activity and prolactin decreased as a result of L-dopa administration. The administration of a peripheral DA₂ dopamine receptor blocker, domperidone (20 mg, orally) prevented the L-dopa-induced reduction in plasma prolactin but failed to block the fall in blood pressure and plasma renin activity. These results suggest that the blood pressure-lowering effect of L-dopa may be mediated through multiple sites involving D₁ dopamine receptors, the central nervous system, and the renin-angiotensin system.

The aim of this study was to assess the value of the early exercise test (ET) in patients with acute myocardial infarction (AMI) treated with IV streptokinase (SK). The authors studied 70 patients with first AMI; 31 were treated with SK and 39 were not. Before discharge everyone was given early exercise up to 5-6 METs and catheterized within 22.9 ± 7.2 days. There was no significant difference in the number of positive ETs between the two groups (11/31 and 14/39 respectively). There was significant difference in favor of: (1) the recanalization of the infarct-related artery in the SK group, (2) the negative ET in patients with recanalized vessels in both groups, (3) the positive ET in patients with multi-vessel coronary disease.

It is concluded that the results of early ET in patients with AMI are related to the recanalization of the infarct-related artery and the coexistence of multi-vessel coronary artery disease, regardless of SK treatment. Patients with successful thrombolysis have negative ET more frequently.

The authors evaluated the effect of Dilevalol infusion on blood pressure, heart rate, central hemodynamics, and rheologic parameters in hospitalized inpatients affected with mild or moderate hypertension.

After a dose-finding phase and a washout period of one week, 10 patients aged fifty to seventy-two-years (median 61.5) were given either a single dose of Dilevalol 60 mg or placebo, and seven days later they underwent the other treatment, according to a single-blind, crossover design. Central hemodynamic measurements were performed by means of M-mode echocardiography, and hemorheologic parameters were evaluated by means of strain-gauge plethysmography. The maximal increase in lower extremity flow at rest had been obtained with the infusion of 60 mg Dilevalol during dose-finding, and so this dose was chosen for the second part of the study. The infusion of Dilevalol significantly increased rest flow and decreased blood viscosity, but the changes in central, parameters were not considered clinically relevant, although statistically significant. Blood pressure decreased without significant changes in heart rate.

Thus, the acute administration of Dilevalol reduced blood pressure, without affecting heart rate and central hemodynamics, confirming the vasodilating effect of the drug. A significant improvement was also shown on blood viscosity in these hypertensive patients.

Abnormal arterial blood flow patterns have been implicated as etiologic factors in thrombosis and atherosclerosis. Intravascular pulsed Doppler ultrasound techniques with fast-Fourier transform analysis offer the opportunity to measure these abnormalities. The authors hypothesized that statistical analysis of radial-directed beam spectra could be used to distinguish disturbed from nondisturbed flow and that analysis of conventional axial-directed beam spectra could then be used to distinguish laminar high-shear from laminar low-shear flow. They developed a scaled-up in-vitro model of coronary flow consisting of a glycerol/H ₂O test fluid flowing through an acrylic cylinder at Reynolds numbers spanning the typical physiologic range within the coronary arteries. A scaled-up Doppler catheter with the capacity for 90° reflection of the beam was placed centrally. Disturbed flow was created by introducing a flow screen, and altered shear rates were produced by changing the Reynolds number. For the radial-directed beam studies, the coefficients of variation of the Doppler spectra for the disturbed flow states were significantly greater than for the nondisturbed flow states (p < 0.01). For the axial-directed beam studies, the coefficients of variation of the Doppler spectra for the laminar high-shear flow states were significantly greater than for the laminar low-shear flow states (p < 0.01). They conclude that abnormal blood flow patterns can be differentiated by the selective use of radial-directed and axial-directed Doppler catheter recordings.

The purpose of this study was to use direct nuclear magnetic resonance (NMR) microscopy to quantitate and image accumulations of atheroma lipids in human coronary arteries and to validate the results by comparison with histologic preparations. NMR microscopy was performed on a superconducting experimental NMR imaging system operating at 2 Tesla with a probe designed for short echo time (TE), strong B ₁ field strength, and small samples. Data acquisition used multiple-offset chemical encoding with offsets based on the thermotropic spectral signature of atheroma lipids within the human arterial vessel wall. Three separate channels of image data yielded color axis display of atheroma within the vessel walls. Atheroma location by histology was identified by rarefaction of stroma, as the lipids are extracted in the process of embedding in paraffin. Perimeters, areas, and a shape index (perimeter²:4πarea) of lumen, atheroma, and outer wall were determined and compared for NMR vs histology. There was no significant difference in the measurements with the exception of luminal shape indices, which were uniformly larger by histology, attributable to flattening of the vessels during histologic preparation. NMR measurement of atheroma content of coronary artery walls agreed well with histology (r = 0.996). NMR microscopy with color axis display proved able to quantitate and image atheroma in coronary arteries, obviating the distortions and lipid removal associated with fixation, embedding, and sectioning for histology.

Quantitative single-photon emission tomographic (SPECT) thallium 201 (²⁰¹Tl) cardiac studies are frequently used to improve test accuracy. One common technique uses polar mapping of relative tracer distribution to compare patient data to emplates from "normal" patient data. Commercial software does not correct for cardiac size variations. This study's purpose was to determine the effect of uncorrected variations in heart size on the variance of the normal population, which is the basis of template significance levels. Twenty-one male volunteers with low probability (< 5%) for coronary disease underwent SPECT-Tl stress test. Data analysis with and without size correction was performed. Data were corrected for size by use of a three-dimensional compression/expansion algorithm. Quantitative data were generated by radial search to maximum activity in short-axis reconstructions. The mean activity and its variance was calculated from 288 points encompassing the myocardium. Mean and variance differences were analyzed by paired t test. There was no difference in activity means (pT > .9), indicating that size correction does not distort the data. The corrected data had, however, significantly lower variance (pT < .0001). This shows that ventricular size variation contributes significantly to "normal" template variance and may adversely affect diagnostic accuracy in the absence of volume correction.

Painful diabetic distal sensory neuropathy is a disabling and common complication of diabetes mellitus. There is evidence that microvascular changes resulting in ischemia to the vasa nervorum may contribute to this problem. Pentoxifylline has been shown to improve circulation through partially occluded peripheral vessels and has been postulated to be of potential benefit. Forty adult type II diabetics were enrolled in a double-blind, placebo-controlled study utilizing pentoxifylline for six months. Visual analog scores, nerve conduction studies, and physical examinations were used to evaluate response to treatment, At the end of the six-month trial, there was no significant difference in the patients' pain between the pentoxifylline- and placebo-treated groups. The authors conclude that pentoxifylline is not useful in the treatment of painful distal diabetic neuropathy.

The authors investigated the involvement of red blood cell aggregation in thrombosis by comparing erythrocyte aggregation in patients with myocardial infarction (28 patients) or cerebrovascular accidents (68 patients) with that in a normal control group (38 subjects). The erythrocyte aggregation was assessed by light transmission aggregometer, and aggregation was induced by hexadimethrinebromide. Increased erythrocyte aggregation was detected in all patients with thrombotic disorders. In addition, patients with diabetes mellitus showed a marked increase in erthrocyte aggregation as compared with those without diabetes. The effect of ticlopidine on erythrocyte aggregation was also studied. It was demonstrated that ticlopidine inhibited aggregation in vitro. An inhibitory effect was shown to be dose dependent, with 10μ M ticlopidine inhibiting aggregation completely. After four weeks' oral administration of 200 mg ticlopidine, there was significant decrease of abnormally increased erythrocyte aggregation in patients with thrombosis.

Splenoportography was performed upon 195 pediatric patients, including 137 by conventional technique and 58 by digital subtraction technique. The results obtained were compared, and it was found that the percentage of diagnosis of spontaneous splenorenal shunt was higher with digital than with conventional technique. In conclusion digital technique is a more sensitive and safer method than the conventional method.

A case of double aortic arch with coarctation of both limbs is described. The patient, a thirteen-year-old girl, demonstrated only the symptoms of coarctation and had no intracardiac anomalies. Discrete coarctation of bilateral limbs distal to the subclavian artery was shown by aortography. Although either double aortic arch or coarctation of the aorta is not so rare, the combination of these two anomalies is quite unusual. This is the third case in the world literature.