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Biomedical subjects

S Zetterquist

Publications and source records attributed to S Zetterquist.

At least 19 recordsLinked to original sources

Does diffuse coronary atherosclerosis affect the relation between coronary stenoses and uptake of thallium-201 after exercise?

It has been proposed that diffuse coronary atherosclerosis influences the myocardial perfusion. We performed a study of 94 young men with previous myocardial infarction in order to find out whether the presence and extent of diffuse coronary atherosclerosis affected the relation between maximal stenosis and myocardial perfusion in areas remote from the infarction. The patients were examined by planar-imaging thallium-201 scintigraphy, following exercise, and coronary angiography within 6 months after myocardial infarction. The maximal distinct stenosis and diffuse coronary atherosclerosis, comprising both plaque size and extent, were semiquantitatively assessed. The correlation coefficients between maximal stenosis within the LAD, RCA, and LCX vascular territories and the corresponding initial uptake of thallium were 0.52 (P = 0.0001), 0.30 (P = 0.04), and 0.46 (P = 0.02), respectively. No change of the correlations was found, except for a slight increase of the r-value from 0.30 to 0.37 in regions corresponding to RCA, after controlling for the diffuse atherosclerosis score in a multiple stepwise regression analysis. These findings indicate no impact of diffuse coronary atherosclerosis on regional myocardial perfusion in areas remote from the infarction.

Angiography

Acute chest pain without obvious organic cause before the age of 40 years: response to forced hyperventilation.

A hyperventilation provocation test (HVPT) was performed on a group (n = 63) of consecutive patients, below the age of 40 years, attending an emergency care unit complaining of chest pain without obvious organic cause. The results were compared with those for a control group (n = 32). There was no tendency to hyperventilate in the patient group, either after discontinuing hyperventilation or during the ensuing relaxation period. PETCO2 measurements during this time thus showed no significant differences between the patient group and the control group. During the HVPT, 44% of patients reported three or more listed symptoms familiar to them from earlier occasions and regarded as typical of hyperventilation, compared to 23% of the controls (P less than 0.05). In a previously reported study, 38% of the patients were found to have similar symptoms during standardized mental stress, despite lack of hypocapnia. It is concluded that, on the basis of PETCO2 measurements, there were no signs of abnormal hyperventilation in the patient group. Moreover, the HVPT did not appear to be specific for diagnosis of hyperventilation syndrome, since mental stress itself was able to reproduce symptoms without concomitant hypocapnia, and since the provocation test was 'positive' in many control subjects.

Adult

Influence of long-term metoprolol treatment on early and late exercise test performance after acute myocardial infarction.

The effect of therapy on exercise performance during a 3-year follow-up after acute myocardial infarction (AMI) was evaluated in a double-blind randomized comparison between 154 patients given metoprolol (100 mg twice daily) and 147 patients given placebo. Exercise tests were performed 1.5, 6, 12, 24 and 36 months after AMI. Maximal accomplished workloads were similar in the 2 groups throughout follow-up. Maximal heart rate was significantly higher in the placebo-treated group throughout the study (p less than 0.001). At the 6-week test more patients in the placebo group terminated exercise due to angina pectoris (40 vs 25%, p less than 0.05) and showed exercise-induced ST-depressions (38 vs 27%, p = 0.05) compared with the metoprolol group. Exercise-induced ventricular arrhythmias were significantly more common in the placebo group during the initial 6 months. Death, another AMI or both were significantly reduced by metoprolol treatment in patients with exercise-induced ST depression greater than or equal to 1 mm at the 6-week test. In a multiple logistic regression analysis maximal accomplished workload at 6 weeks (p less than 0.026), male sex (relative risk [rr] = 3.57, p = 0.016), previous AMI (rr = 3.07, p = 0.001), therapy with placebo (rr = 2.14, p = 0.007) and left ventricular failure (rr = 2.04, p = 0.023) were shown to carry independent prognostic information as well as exercise-induced ST-depression (greater than or equal to 1 mm) in placebo-treated patients (rr = 2.70, p = 0.01).

Clinical Trials as Topic

One-year sequential follow-up of venous emptying rate and leg temperature profiles after acute deep vein thrombosis.

In order to study the natural course of venous flow and temperature reaction in the legs after symptomatic first episode of deep vein thrombosis (DVT), 65 patients (57 with proximal DVT) without further thromboembolic complications during the observation period were followed for 1 year by repeated plethysmography (PG) and thermography (TG). Regarding the non-invasive parameters substantial individual variations was observed during the observation period. After 1 year pathologic PG and TG were still demonstrated in 39% (I mu (95%) = /0.43 +/- 0.05/) and 65% (I mu (95%) = /1.18 +/- 0.11/), respectively, of the patients after proximal DVT. Only a minority of the patients were normalized permanently in both PG and TG during the first year. The high frequency of remaining venous obstruction and especially, persistent thermoactivity is notable and may be of clinical importance.

Adult

Results of surgical treatment for iliofemoral venous thrombosis.

The long-term results after venous thrombectomy combined with a temporary arteriovenous fistula were evaluated in 19 patients. Clinical status, isotope phlebography, venous occlusion plethysmography and foot volumetry were performed after a mean follow-up time of 38 months (range 13-75). The primary operation was successful in 17 of the 19 patients; the 2 remaining had chronic occlusions of their iliac veins. At the time of closure of the arteriovenous fistula, i.e. 3 months after thrombectomy, 14 patients had a patent iliac vein. At follow-up eight patients were considered to have a patent iliac vein, eight had a partial restitution and three had an occluded iliac vein. The group as a whole had no impaired venous emptying of the leg, but the small group of patients with occlusion at follow-up according to isotope phlebography seemed to have an impaired venous emptying. Foot volumetry showed only minor signs of valvular insufficiency, mainly in limbs with distal extension of the initial thrombus or only partial restitution of venous patency. A good long-term result can be expected after venous thrombectomy with a temporary arteriovenous fistula particularly in younger patients where the thrombosis is limited to the iliofemoral segment. This emphasizes the importance of early operation before distal extension of the thrombus occurs.

Adolescent

Repeated exercise and redistribution thallium-201 scintigrams in patients with myocardial infarction treated with timolol or placebo.

Repeat exercise thallium-201 scintigrams were performed 2 weeks, 3 months, and 6 months in 27 patients following their first myocardial infarction. All patients were treated with timolol or matching placebo, administered intravenously starting within 5 hours of onset of chest pain. The extent of transient perfusion defects in 15 timolol-treated patients increased significantly between 2 weeks and 3 months compared to a decrease in 12 placebo-treated patients (p less than 0.05). Between 3 and 6 months the extent of transient defects did not change in the two groups, and there was no difference between the groups. The extent of permanent defects was not significantly different between the timolol- and placebo-treated patients on any occasion. However, patients in the timolol group had a decrease in permanent defects with time in contrast to patients in the placebo group (p less than 0.05). Thus, early intervention with timolol in the acute phase of myocardial infarction may have consequences for the postinfarction phase, as reflected in repeat thallium-201 scintigrams.

Adult

One-month versus six-month therapy with oral anticoagulants after symptomatic deep vein thrombosis.

The length of time for which deep vein thrombosis (DVT) should be treated with oral anticoagulants (OA) is controversial. In this study, 135 patients with symptomatic first period DVT (83% with proximal DVT) were randomly allocated to OA for one or six months. The diagnosis of initial and recurrent DVT was confirmed by phlebography or plethysmography and thermography, or by a combination of all these methods. Pulmonary emboli were confirmed by lung scans or at autopsy. The patients were followed for at least one year. One patient had to discontinue OA prematurely because of haemorrhage. Seventeen patients left the project for other reasons, ten during and seven after therapy; in one of these DVT recurred. The recurrence rate during the first year was high (17% symptomatic recurrences) irrespective of whether OA had been given for one or six months.

Adult

Leg temperature profiles with a simplified thermographic technique in the diagnosis of acute venous thromboses.

A simplified thermographic technique has been developed to provide continuous leg temperature profiles by manual scanning with a noncontactile infrared radiation transducer connected to a linera potentiometer for determination of the transducer position. The clinical value of the technique in the diagnosis of acute venous thromboses has been estimated in seventy patients and thirty controls, using plethysmography and phlebography as methods of reference. The thermographic diagnosis was based on side differences in temperature levels within different segments of the limbs, as calculated from the temperature profiles by means of planimetric technique. Standardized temperature profiles from the medial side of the limbs were found to demonstrate a side difference above the reference level in fifty-seven of fity-nine patients with acute venous thromboses, which means a diagnostic sensitivity corresponding to that of conventional thermography. Skin temperature profiles were superior to plethysmography, particularly in the diagnosis of thromboses located distally. Falsely positive results were obtained, as expected, in some cases of varicose veins or acute arthritis and skin infections. The presented type of thermography has obvious qualifications as a screening method in the early diagnosis of acute venous thromboses, being far less expensive but never the less more suited for objective numerical analyses and evaluation than conventional thermography with scanning cameras.

Acute Disease

Early work load tests for evaluation of long-term prognosis of acute myocardial infarction.

Exercise tests performed 3 and 9 weeks after acute myocardial infarction in 205 patients were found to give prognostic information on the survival during a follow-up period of 2 to 5 years. The appearance of tachycardia, major ventricular arrhythmias, or anginal complaints during these early exercise tests was thus accompanied by a significantly increased mortality during the observation period. Ventricular arrhythmias disclosed by exercise proved to be of higher prognostic significance than those recorded at rest on the same occasions. The usefulness of early exercise tests in the evaluation of the response to antiarrhythmic treatment after acute myocardial infarction as well as of the prognostic importance of the effects was documented in a smaller series of patients.

Acute Disease

Streptokinase treatment of deep venous thrombosis of the lower extremity. Clinical, phlebographic and plethysmographic evaluation of early and late results.

The investigation comprises 19 patients with acute deep vein thrombosis of the leg treated with streptokinase. The acute clinical symptoms rapidly subsided in 15 patients. Phlebography, performed immediately after treatment, revealed complete thrombus regression in 7 cases, restoration of venous flow but remnants of thrombi in 4 and no effect in 7. One woman was not evaluated radiologically due to pregnancy. The phlebographic restoration seemed to be correlated to the duration of the thrombotic symptoms. Follow-up examinations 6-50 months after the thrombotic incident demonstrated normal phlebograms in 8 patients, all of whom were also free from post-thrombotic symptoms. Venous occlusion plethysmography confirmed that these patients had a normal venous outflow capacity and valvular function in the relevant limbs. By contrast, the remaining 11 patients, with more or less extensive remnants of thrombi at the follow-up phlebography, were found to have plethysmographic signs of venous obstruction and sometimes also valvular insufficiency. The results indicate that thrombolytic treatment is able to give a complete and lasting anatomical and functional restitution of the deep veins after an acute thrombosis in the leg, provided that treatment is induced early enough.

Adult

The clinical significance of biphasic venous emptying curves from the lower limb in venous occlusion plethysmography.

The utilization of venous occlusion plethysmography in the routine diagnosis of acute venous thrombosis in the leg has disclosed a previously unreported type of biphasic venous emptying curve that has proved to be of special diagnostic significance. The examinations were undertaken with a Dohn plethysmograph for segmental application of the calf. The emptying curves in question had an initial phase at the ordinary rapid rate, changing distinctly within 1.5 sec into a definitely slower phase of venous emptying. Biphasic emptying curves were found to be characteristic of patients with isolated, high venous obstruction, mostly acute thromboses, but more or less intact veins in peripheral parts of the leg. The same type of pathological emptying curves could be provoked by external compression of the femoral vein or Valsalva's manoeuvre, providing experimental evidence of the underlying mechanism. The venous emptying course might be similarly influenced also by varicose veins, pregnancy, and right heart failure. The diagnostic experience of biphasic emptying curves in clinical practice indicates, that this particular way of interpreting venous occlusion plethysmography is a valuable complement to phlebography in the detection of proximal venous obstructions in the lower limb, whether due to iliac thrombosis or elusive intrapelvic tumours.

Acute Disease