Detection of autonomic sympathetic dysfunction in diabetic patients. A study using laser Doppler imaging.

OBJECTIVE: To study signs of the disturbed reflex autonomic sympathetic nerve function in type 1 and type 2 diabetic patients. RESEARCH DESIGN AND METHODS: Measurements were made on 15 type 1 (duration 13-32 years) and on 50 recently diagnosed type 2 diabetic patients (duration 3-4 years). The vasoconstrictor responses in the distal phalanx of the middle finger (locally heated to 40 degrees C) to the cooling of the contralateral arm were measured using Laser Doppler Imaging (LDI). A vasoconstriction index (VAC) was calculated taking age into account and was compared with reference values obtained in 80 control subjects. The diabetic patients were also studied with deep-breathing tests (i.e., the heart-rate variation expressed as the expiration-to-inspiration [E/I] ratio, a test of parasympathetic nerve function). RESULTS: The vasoconstrictor responses to indirect cooling (VAC) were significantly reduced in the fingers of the diabetic patients, both type 2 (0.77 +/- 0.02 V; P < 0.01) and type 1 (0.83 +/- 0.04 V; P < 0.001), compared with the healthy control subjects (0.65 +/- 0.01); the age-corrected VAC (VACz) was slightly more impaired in type 1 than in type 2 diabetic patients. The frequency of an abnormal VACz corresponded well to the frequency of an abnormal E/I ratio in type 1 diabetic patients (approximately 50%), whereas the frequency of an abnormal VACz was significantly higher than an abnormal E/I ratio among type 2 diabetic patients (11/50 vs. 4/50; P < 0.05). CONCLUSIONS: Both type 1 and type 2 diabetic patients have impaired cutaneous blood flow regulation. The VAC index seems to be a promising tool for detection of subclinical changes in autonomic sympathetic function.

Effects of nitroglycerin and dipyridamole on acute myocardial infarction: a thermographic study in the dog.

The effects on an acute myocardial infarction of equipotent hypotensive doses of nitroglycerin and dipyridamole were studied using the thermographic technique in open-chest dogs. Nitroglycerin did not reduce the cool ischaemic area in any of the nine dogs studied. In six of the dogs, in which the ischaemic region could be properly measured, the cool area slightly grew in size. Dipyridamole reduced the size of the ischaemic area in all the 20 dogs used. In the 19 in which the size could be adequately digitalised, the decrease in infarction size was statistically significant.

Effects of oxygen on acute myocardial infarction: a thermographic study in the dog.

An acute myocardial infarction was created in a series of dogs by ligation of a branch from the left anterior descending coronary artery. The effects on the infarction with 100% oxygen were studied by thermography in 23 animals. The changes in the infarction size were registered on polaroid photographs. In 10 dogs the infarction showed a uniform cool area, permitting accurate measurement by cutting out and weighing the black, infarcted area from the photographs. During oxygen administration 2 dogs showed a considerable increase in the cool area and 6 other dogs a moderate but significant increase. The remaining 2 dogs in this group showed non-significant change in the infarcted area. In the other 13 animals the cool area was not sufficiently uniform to allow accurate measurement. However, all the dogs in this group, except one, presented a visable increase of the cool area of varying degree. High oxygen supply does not seem to have a favourable effect on an experimentally induced acute myocardial infarction. It is known to promote a lowering of the coronary artery perfusion pressure. In addition to this, it may somehow decrease the arterial supply from the vascular bed round the ischaemic area.

Postoperative deep venous thrombosis after renal transplantation. Effects of cyclosporine.

In this prospective study the frequency of deep venous thrombosis during the first three weeks after renal transplantation was determined using a combination of strain gauge plethysmography and thermography for objective diagnosis. Ninety-seven consecutive patients were studied, 30 patients having juvenile diabetes mellitus. As immunosuppression cyclosporine and low-dose steroids were used. The series was compared with a similar group of 83 patients, 33 having juvenile diabetes mellitus treated with azathioprine and high-dose steroids as immunosuppression, in which the diagnosis of deep venous thrombosis was made with an identical technique. The overall frequency of thrombosis was 9.3% in the cyclosporine-treated group, which is a significant reduction in comparison with the azathioprine group (24.1%). It is concluded that the combination of cyclosporine and low-dose steroids does not increase the frequency of deep venous thrombosis in comparison with azathioprine and high-dose steroids in renal transplanted patients.

Cutaneous vasomotor responses in young type I diabetic patients.

Abnormal skin temperature reactions have been reported in type I diabetic patients. Whether this is due to a primary vascular disturbance or autonomic neuropathy is unclear. The aim of this study was to clarify this issue by evaluating cutaneous circulatory reactions before and after provocation. Seventeen type I diabetic patients and 17 age-matched controls were studied by recording blood flow (laser Doppler technique) on the dorsum of the hand (before, during, and after arterial occlusion), blood flow and skin temperatures on the dorsum of the foot and on the toe (before and after cooling followed by indirect body heating) and autonomic nerve function (heart rate reaction to deep breathing and to tilting). The results showed that before [4.6 +/- 0.5 perfusion units (PU) versus 6.1 +/- 0.7 PU; p = 0.0356] and after arterial occlusion (17.5 +/- 1.6 PU versus 25.3 +/- 1.7 PU; p = 0.0024), hand skin blood flow was significantly lower in patients than in controls. On the dorsum of the foot, skin temperatures was significantly lower in patients than in controls before cooling (29.2 degrees C +/- 0.3 degrees C versus 30.5 degrees C +/- 0.4 degrees C; p = 0.0107) whereas toe temperature and toe blood flow were similar before and after cooling in patients and controls. After body heating, however, toe temperature (after 30 min: 25.2 degrees C +/- 1.4 degrees C versus 30.9 degrees C +/- 1.2 degrees C; p = 0.0022) and toe blood flow (after 30 min: 10.9 +/- 2.5 degrees C versus 22.9 +/- 4.9 PU; p = 0.0313) were significantly lower in patients than in controls, especially in patients with parasympathetic neuropathy (i.e., patients with abnormal heart rate reactions to deep breathing). In conclusion, type I diabetic patients demonstrated a vascular disturbance in their skin that seemed to be exaggerated by parasympathetic neuropathy.

Comparison of 133Xe clearance and laser Doppler flowmetry in assessment of blood flow changes in human masseter muscle induced by isometric contraction.

Changes induced by 30 s of isometric contraction at 10% and 50% of the maximum voluntary contraction were assessed in 10 healthy subjects; there was a median increase of 1.8 and 0.3 times in 133Xe clearance and 5.3 and 2.7 times in laser Doppler flowmetry. In the first minute after 10% maximum voluntary contraction, 133Xe clearance increased 12.1 times in relation to the initial resting level, and flowmetry values decreased to become 3.5 times higher than the basal flow; corresponding values after 50% maximum voluntary contraction were 24.3 times and 3.7 times. From the second minute after contraction, there was a rapid decrease in 133Xe clearance and a slow decrease in flowmetry values. Five minutes after biting at 10% maximum voluntary contraction, both methods showed a total net increase of about 15 times; after biting at 50% maximum voluntary contraction the corresponding values were 38 and 23 times. Thus laser Doppler flowmetry can be used to assess changes in blood flow in the masseter; it registers a greater increase in flow during isometric contraction than does 133Xe clearance. The significant difference between methods immediately after either chosen level of contraction disappears when the total net post-contraction hyperaemia is assessed over a period of 2 and 5 min, respectively.

A device for noninvasive assessment of perfusion pressure in the skin of healthy volunteers.

A device allowing pressure to be applied to a local skin site where the skin blood flow is followed using laser Doppler flowmetry is described. The blood flow was studied on the back of the hand in eight volunteers before and during brachial arterial occlusion and while the external pressure was increased step by step. The flowmetry value during arterial occlusion was 0.3 +/- 0.1 AU, and when the external pressure was increased to 120 mm Hg the values were similar (p = .44). The skin perfusion pressure, defined as the least external pressure needed to achieve flow cessation, was found to be 92 +/- 16 mm Hg (range 70-111 mm Hg), and the mean arterial pressure was 90 +/- 9 mm Hg (NS). The skin perfusion value is in agreement with that found by others using other techniques for measuring blood flow and a circumferent cuff for applying pressure.

Skin perfusion pressure assessed by measuring the external pressure required to stop blood cell flux.

Laser Doppler flowmetry (LDF) was used to determine the point at which blood flow cessation is achieved under circumferentially applied external counter pressure at the ankle level. In 13 individuals with a normal ankle index, the flow of cessation external pressure (FCEP) was, on average, 28 mmHg lower than the systolic ankle pressure (range: 7-62). In 19 patients with an ankle index below 1.0, FCEP correlated with the ankle pressure (rs = 0.76) and even more closely with the ankle index (rs = 0.82). In patients with a more pronounced degree of arterial occlusive disease, FCEP can be equal to or even higher than the ankle pressure. This may be due to a release of sympathetic vasoconstrictor tone and possibly to the presence of a collateral circulation supplying the skin. Individual LDF values from the skin at rest do not reflect the degree of peripheral circulatory insufficiency.

Laser Doppler imaging of finger skin blood flow in patients after microvascular repair of the ulnar artery at the wrist.

Laser Doppler imaging is a new, non-invasive technique allowing the spatial distribution and the temporal variation of the skin blood flow to be monitored. A mean blood flow value over an area, such as the finger-tip in the present study, can also be calculated. Recordings from 12 patients with a sutured ulnar artery following trauma did not significantly differ from those obtained in 14 controls. Four patients with a ligated ulnar artery, however, showed a slower restitution of blood flow values after cold provocation. All sutured ulnar arteries were found to be patent, which confirms that microvascular reconstruction of an injury to the ulnar artery at the wrist is worthwhile.

Is vibration-induced white finger a reversible syndrome if vibration is stopped?

The purpose of the study was to investigate if vibration-induced white finger may be a reversible symptom after cessation of vibration exposure. Fifty-nine welders, previously employed by a ship building company and who had shown various levels of vibration-induced vasospastic symptoms in the hand were interviewed 5 to 6 years after closure of the company. Out of the 43 patients exposed to no or insignificant vibration subsequently, 28 claimed improvement, 11 claimed unchanged problems and four complained of worse problems. Twelve of these patients had the cold provocation test repeated at follow up. One patient showed the same result as 5 years earlier, six showed improvement and five showed much improvement. Of 16 patients with continued vibration exposure none showed subjective improvement, nine claimed unchanged problems while seven patients were worse. It is concluded that vibration-induced white finger is not a progressive condition following cessation of exposure to vibration. On the contrary it may be static or even reversible to some extent.

Venous haemodynamics of the upper extremity after subclavian vein thrombosis.

Late post-thrombotic complaints after subclavian vein thrombosis are reported with highly varying frequencies (8-80% severe disability). The therapeutic approach depends partly on this frequency. With the aim to evaluate late sequelae a questionnaire was answered by 26 patients with arm-shoulder symptoms leading to arm phlebography, but where the examination did not reveal any thrombi. 65% had remaining symptoms 2-9 years after the examination. 3 had to change profession. 36 patients with phlebographically shown subclavian vein thrombosis answered the same questionnaire. Only 9 (25%) had remaining symptoms and in 4 it was classified as mild, in 4 as moderate and only in 1 patient as severe leading to change of profession. Venous haemodynamics in the upper extremity were also studied in 3 groups of patients; I) healthy volunteers (n = 16 arms), II) patients with arm-shoulder disabilities with negative arm phlebography (n = 7 disabled arms, n = 7 non-disabled arms), III) patients with phlebographically verified subclavian vein thrombi (n = 10 arms with DVT, n = 8 arms without DVT). Strain gauge plethysmography was used measuring venous capacity and maximal venous outflow. Venous pressure measurements were made both with the arms in a resting position and in a military position with and without work-load. Repeat phlebography of arms with symptoms were made. Maximal venous outflow was significantly lower in arms with previous subclavian vein thrombi (p less than 0.05) and venous pressure measurements with the arm in military position was significantly higher in those arms. However, no correlation between these measurements and the degree of arm disability was noted.(ABSTRACT TRUNCATED AT 250 WORDS)

Leg showering therapy in patients with intermittent claudication.

Ten patients with intermittent claudication were treated using a recently constructed "chair" in which the seated patient has alternately warm and cool water flushed over the legs and feet. A trial treatment was given for 25 minutes, three times a week for 5 weeks. Ankle/arm index, skin perfusion pressure and calf blood flow all remained unchanged immediately after such a series of treatment. Even at follow-up 6 months later, values were unchanged but for a minute increase in ankle/arm index in the poorer leg. Walking capacity was additionally measured and an improvement was seen, also after 6 months. The role of the contrast temperature treatment in this improvement is, however, unclear.

Effects of transcutaneous nerve stimulation on the microcirculation in chronic leg ulcers.

The purpose of this study was to find out to what extent transcutaneous electrical nerve stimulation (TENS) affects the blood flow in and around chronic lower leg ulcers, as measured with a new technique, laser Doppler imaging (LDI). Fifteen patients, mean age 73 years (range 38-85) with chronic leg ulcers of various causes participated in the study. The duration of the ulcers ranged from 3 months to 16 years. Low-frequency (2 Hz; 10-45 mA) TENS was given for 60 minutes. The changes in blood flow were measured every 5 minutes by LDI. After 60 minutes, mean blood flow had increased in the ulcer by 35%, and in the intact skin surrounding the ulcer by 15%. Even 15 minutes after the TENS had finished there was still a mean blood flow increase of 29% in the ulcer and 9% in the skin. The present results show that TENS has a stimulating effect on local blood circulation in and around chronic ulcers.

Acute effects of doxazosin and atenolol on smoking-induced peripheral vasoconstriction in hypertensive habitual smokers.

The acute effects of selective alpha 1 inhibition with doxazosin (0.5-0.7 mg intravenously) and beta 1-blockade with atenolol (0.1 mg/kg body weight, intravenously) on smoking-induced peripheral vasoconstriction were investigated in 24 hypertensive habitual smokers. Forearm blood flow was measured by venous occlusion plethysmography and skin blood flow was estimated by thermography and laser doppler flowmetry. After the patients had smoked two cigarettes, plasma adrenaline elevations were similar under basal conditions and after drug administration; plasma noradrenaline remained unchanged. The smoking-induced increase in the heart rate was attenuated by atenolol compared with basal values. The smoking-induced increase in systolic blood pressure was more marked after atenolol and doxazosin (P less than 0.05) than before the drug administration. The smoking-induced increase in diastolic blood pressure was enhanced by atenolol (P less than 0.05) but unchanged by doxazosin. Smoking increased forearm vascular resistance under basal conditions (P less than 0.05) and after atenolol (P less than 0.01) but not after doxazosin. Similarly, skin temperature was significantly reduced by smoking under basal conditions and after the administration of atenolol (P less than 0.001) but not doxazosin. The smoking-induced reduction in skin blood flow was attenuated by doxazosin compared with atenolol (P less than 0.05). Thus, smoking-induced muscular and cutaneous vasoconstriction was inhibited by doxazosin as opposed to atenolol in hypertensive habitual smokers. This may reflect unmasked beta-adrenoceptor mediated vasodilation in addition to attenuated alpha 1-adrenoceptor mediated vasoconstriction.

Thermography and laser-Doppler flowmetry for monitoring changes in finger skin blood flow upon cigarette smoking.

Haemodynamic changes after smoking two 1.1 mg nicotine cigarettes were monitored in 24 smokers on two different occasions. Smoking caused an increase in heart rate and arterial blood pressure, whereas finger temperature as measured by thermography and finger skin blood flow as measured by laser-Doppler flowmetry (LDF) decreased. Lowest values were seen within 15 min by LDF, and after 30 min by thermography. Changes in the two methods correlated closely, however, when maximum responses during a 45-min period after smoking were compared. The wider distribution of LDF values would seem to be due to the small measuring volume which is susceptible to differences in vascular anatomy and reactivity. In both methods, responses showed a high degree of reproducibility.

Wound healing after total elbow replacement in rheumatoid arthritis. Wound complications in 50 cases and laser-Doppler imaging of skin microcirculation.

Wound healing complications, predisposing to deep infection, are common following prosthetic surgery of the elbow. 50 capitellocondylar elbow prostheses were inserted, using a lateral approach, in 42 patients with rheumatoid arthritis. The first 5 elbows were immobilized postoperatively for 5 days and the following 45 elbows for 12 days, because of delayed wound healing in 2 of the first 5 elbows. No wound healing complications were recorded in elbows immobilized for 12 days and elbow motion was not compromised. 5 elbows were investigated with laser-Doppler imaging (LDI) technique, both pre- and postoperatively. Postoperative LDI values were considerably higher than preoperative ones, indicating no impairment of local skin microcirculation. The authors conclude that the lateral approach is safe to use in prosthetic surgery on the elbow. Early mobilization can delay wound healing, but this can be prevented by 2 weeks of postoperative immobilization.

Thermography after subcutaneous mastectomy and reconstruction with silicone gel prosthesis: a pilot study.

Patients with subcutaneously placed silicone gel prostheses, for reconstruction after subcutaneous mastectomies, often complain of cold breasts as well as of slow regaining of warmth after cooling. We have used thermography in 7 such women and in 7 healthy women of the same age group as controls. Thermography has also been used in 3 women after repositioning of the subcutaneously placed prostheses to a submuscular position in order to study any possible changes in temperature. In 2 cases thermography also was found to aid in the diagnosis of a suspected subcutaneous displacement of a submuscular prosthesis; the technique has an advantage over mammographic examination, since thermography is a simple, less expensive, and safer method.