Local cold exposure test for capillaroscopic examination of patients with Raynaud's syndrome

Quantitative nailfold capillaroscopy-update and possible next steps

We review the exciting potential (and challenges) of quantitative nailfold capillaroscopy, focusing on its role in systemic sclerosis. Quantifying abnormality, including automated analysis of nailfold images, overcomes the subjectivity of qualitative/descriptive image interpretation. First we consider the rationale for quantitative analysis, including the potential for precise discrimination between normal and abnormal capillaries and for reliable measurement of disease progression and treatment response. We discuss nailfold image acquisition and interpretation, and describe how early work on semi-quantitative and quantitative analysis paved the way for semi-automated and automated analysis. Measurement of red blood cell velocity is described briefly. Finally we give a personal view on 'next steps'. From a clinical perspective, increased uptake of nailfold capillaroscopy by general rheumatologists could be achieved via low-cost hand-held devices with cloud-based automated analysis. From a research perspective, automated analysis could facilitate large-scale prospective studies using capillaroscopic parameters as possible biomarkers of systemic sclerosis-spectrum disorders.

A Randomized Controlled Trial of Acupressure for the Treatment of Raynaud's Phenomenon: The difficulty of conducting a trial in Raynaud's phenomenon

OBJECTIVE

To examine the effect of acupressure on Raynaud's phenomenon (RP) in a randomized controlled clinical trial (RCT) and to evaluate the difficulties of conducting a RP RCT.

METHODS

A pilot single center RCT of acupressure vs. targeted patient education was conducted for the treatment of RP. Patients with either primary (N = 15) or secondary (N = 8) RP were randomized in an 8-week study. The primary endpoints included a decrease in the frequency and duration of RP. Secondary endpoints included several serum biomarkers including endothelial dysfunction, Raynaud's attack symptoms, Raynaud's Condition Score, and patient and physician global assessments of RP. Primary data analysis was conducted using the last observation carried forward and t-tests or a Wilcoxon rank test was used to compare the two groups.

RESULTS

23 patients were randomized and 7 discontinued prematurely. 78% of patients were female, 96% were Caucasian, and the mean age was 49.8 (SD=16) years. No statistically significant differences were detected between the acupressure vs. education groups in primary and secondary outcomes (p> 0.05). Frequency of attacks decreased by 6.7 attacks (SD=8.8) in the acupressure group vs. 7.2 (SD=12.8) in the education group (p=0.96), and the duration of attacks decreased by 11.4 (SD=19.9) minutes in the acupressure group vs. an increase of 0.8 minutes (SD=11.2) in the education group (p=0.14). There were no adverse events noted in the RCT.

CONCLUSION

This pilot study does not support efficacy of acupressure for RP.

Digital-Artery-Closing Temperatures: An Objective Index of Severity in Raynaud's Phenomenon

Evidence suggests that the color changes of Raynaud's phenomenon (RP) are initiated by spasm of the digital arteries. High-frequency A-mode ultrasound can be used to measure digital artery diameters, and in a group of patients suffering RP, the authors used it to monitor the development of digital artery spasm in fingers that had been progressively cooled. The present study evaluated the reproducibility and value of the temperature at which digital artery spasm occurs (digital-artery-closing temperature) as an objective index of RP severity. Forty-five subjects suffering RP were included (32 suffering primary RP and 13 secondary RP). All were assessed clinically by an independent physician and classified as suffering mild, moderate, or severe RR In 3 of these subjects, digital-artery-closing temperatures were determined on five separate days. The coefficients of variation for digital-artery-closing temperatures recorded in the 3 subjects were low (< 4%), confirming reproducibility. The technique failed in 1 subject suffering severe RP. In the 44 remaining subjects, digital-artery-closing temperatures correlated with clinical assessment. The mean digital-artery-closing temperatures and standard deviations for the three groups were: mild=18.31±1.07°C; moderate=20.83±1.32°C; severe = 25.53±1.38°C. The differences in closing temperatures between the groups were highly significant (P < 0.001, Mann Whitney). The maximum digital artery diameters recorded in the primary RP (including vibration white finger) subjects (Mean±Std Dev=1.21±0.14 mm) were larger than those in the secondary RP subjects (Mean±Std Dev=0.88±0.17 mm). This difference was highly significant (P < 0.001, Mann Whitney).

N-acetylcysteine improves microcirculatory flow during smoking: new effects of an old drug with possible benefits for smokers

BACKGROUND

Cigarette smoking provokes marked acute changes in the microcirculatory vasculature, including a reduced blood flow velocity. In accordance with the hypothesis that the reduced blood flow is due to an imbalance between pro-oxidants and oxidants, we recently showed that most of the reduction could be reversed by a high dose of vitamin C.

HYPOTHESIS

In the present work we tested the hypothesis that N-acetylcysteine, a mucolyticum and an antioxidant, may have an effect on the smoking-induced changes observed by vital capillary microscopy of the nailfold.

METHODS

In all, 37 healthy volunteers of both genders and with varied smoking habits were treated with N-acetylcysteine 200 mg t.i.d. for 2 weeks. In vivo investigation of the microcirculation by capillaroscopy was performed before and after treatment.

RESULTS

Treatment with N-acetylcysteine significantly reduced the smoking-induced relative decrease in capillary blood flow velocity in a group of volunteers with varied smoking habits (p = 0.0016). The preventive effect was clearly significant in smokers (p = 0.003).

CONCLUSION

Treatment with N-acetylcysteine has a positive impact on microcirculatory flow during smoking, particularly in habitual smokers.

A cold-response index for the assessment of Raynaud's phenomenon

BACKGROUND

Quantification of Raynaud's phenomenon (RP) is a prerequisite in the evaluation of novel therapeutic strategies. Fingertip rewarming in response to local cold provocation has been used in many studies but not been systematically validated. We have previously described the time elapsed before 63% of pre-cooling temperature is reached as a RP activity index.

OBJECTIVE

A comprehensive evaluation of fingertip rewarming in primary and scleroderma-associated RP.

METHODS

We defined a cold-response index (CRI) as the log transformation of the 63% rewarming time upon cold challenge.

RESULTS

The CRI shows high intra-individual reproducibility. The mean CRI values were (mean+/-S.D.): 2.4+/-0.3 in controls (n=53) versus 2.7+/-0.3 in RP (n=50, p<0.0001 versus controls), and 2.7+/-0.3 in scleroderma patients (n=46, p<0.0001). In addition, baseline fingertip temperature was also found to be significantly reduced both in primary as well as scleroderma-associated RP. Kinetic analysis of rewarming temperature curves demonstrates that the CRI is independent of individual rewarming patterns. Finally, the CRI decreases significantly upon a single low-level systemic hyperthermia treatment in scleroderma patients (2.68+/-0.28 before versus 2.45+/-0.33 after, p=0.0003), while the extent of cooling remained unchanged, thus demonstrating sensitivity to change.

CONCLUSION

Our results provide a solid basis for using the cold-response assay as an endpoint in addition to clinical activity scores in RP treatment trials.

Periodontal microcirculatory abnormalities in patients with systemic sclerosis

BACKGROUND

The aim of this study was to observe the differences in periodontal microcirculation between healthy patients and patients with systemic sclerosis (SSc).

METHODS

Fifteen healthy patients and 15 patients with SSc were examined. Periodontal capillaroscopy was used to investigate the characteristics of microcirculation. The visibility, course, tortuosity, possible presence of microhemorrhages, average caliber of the capillary loops, and number of visible capillary loops per square millimeter were evaluated for each patient.

RESULTS

The investigation was simple, non-invasive, and repeatable for each patient. In patients with SSc, it was possible to observe a reduced number of capillaries and a greater capillary diameter and tortuosity.

CONCLUSIONS

Capillary alterations in patients with SSc are not limited to the nailfold bed but also occur in periodontal mucosa microcirculation. Such evidence could be extremely important in the pathogenesis and treatment of periodontal diseases in patients with SSc.

Vascular imaging

Many rheumatic diseases affect the vasculature, either as a 'primary' manifestation of the disease process (as in vasculitis or scleroderma-spectrum disorders) or as a result of accelerated atherosclerosis. Recent years have seen very major developments in, and refinements of, vascular imaging methods. It is likely that this pace of development will continue, enhancing the rheumatologist's ability to diagnose different musculoskeletal conditions and follow their progression, using minimally invasive techniques. In this chapter, we describe these recent advances in vascular imaging techniques, concentrating on those most relevant to the practising clinician, but also discussing methods which are being used in clinical research. Three main groups of imaging modalities are described: large vessel imaging (X-ray, magnetic resonance (MR) and computed tomography (CT) angiography), nailfold microscopy and thermography. For each of these, the method(s) and then the clinical and research applications are discussed. Laser Doppler, a research technique, is also described.

Quantitation of microcirculatory abnormalities in patients with primary Raynaud's phenomenon and systemic sclerosis by video capillaroscopy

OBJECTIVE

: To assess nailfold capillary density and dimensions in patients with primary Raynaud's phenomenon (PRP), limited cutaneous systemic sclerosis (LSSc) and diffuse cutaneous SSc (DSSc), and healthy control subjects.

METHODS

: Using the technique of nailfold video capillaroscopy, capillary density and dimensions were averaged from all visible capillaries in a 3 mm length of the nailfold from right and left ring fingers of each subject. Twenty healthy control subjects, 15 patients with PRP, 13 patients with DSSc and 21 patients with LSSc were examined. Intra-observer and inter-observer variability were calculated in 18 and 23 patients, respectively.

RESULTS

: There were significant trends for capillary density to fall and for all dimensions to rise across the four groups (P < 0. 0001 for density and all dimensions, order healthy controls, PRP, DSSc and LSSc). Intra- and inter-observer reproducibility studies showed that although there was good correlation between and within observers, the limits of agreement were between +/-25-50% indicating lack of reproducibility.

CONCLUSIONS

: Microcirculatory abnormalities can be quantified using the technique of video capillaroscopy and were most marked in patients with LSSc.

Influence of the ultrasound contrast agent Levovist on human nailfold capillary microcirculation

Little is known about the behavior of ultrasound contrast microbubbles in human capillaries. The evaluation of circulatory effects of echo contrast media may bring valuable information for the interpretation of echo contrast phenomena in the human myocardium. In 12 healthy volunteers (aged 31 +/- 6.7 years; five women), nailfold capillaries were examined by means of TV microscopy. The authors investigated acral microcirculation at rest and after local cold application with and without saccharide-based microbubbles (10 mL Levovist 300 mg/mL IV). The mean blood flow velocity at rest was 1.18 +/- 0.18 mm/s (mean value +/-1 SD) and 1.11 +/- 0.11 mm/s (mean value +/- 1 SD) after the injection of Levovist (ns). One minute after local cold exposure a decrease of the blood flow velocity by 61% before and by 75% after intravenous Levovist was found. In both groups the cold-induced decrease of blood flow velocity was statistically significant (p<0.01), whereas there was no significant difference in flow reaction between the two groups. No wall adhesion of blood cells or extravasation of contrast into the surrounding tissue was detected. After intravenous injection of a regular dose of saccharide-based microbubbles Levovist, no change of blood cell flow velocity and no wall adhesion or extravasation could be found at rest and after cold application in human nailfold capillaries. Since microcirculatory flow characteristics in the finger nailfold capillaries are not influenced by Levovist, it might be assumed also that myocardial blood flow behavior remains unchanged, so that this contrast agent may be used as a flow tracer for cardiac investigation.

Reduced ocular pulse amplitude in low tension glaucoma is independent of vasospasm

PURPOSE

A vascular basis for the pathogenesis of primary open angle glaucoma has been postulated for many years. Defects in the regulation of ocular blood flow may be the initiating factor in this group of multifactorial diseases. This study was designed to evaluate the effect of vasospasm on ocular pulse amplitude (OPA) in low tension glaucoma (LTG) patients.

METHODS

OPA, using the Langham Ocular Blood Flow (OBF) System, applanation intraocular pressure (IOP), systemic blood pressure and heart rate were measured and vasospasm was determined by a fingernail capillary blood flow test.

RESULTS

OPA (mmHg) in the LTG patients with a vasospastic reaction (LTG-V, 1.4 +/- 0.1, n = 17) was not significantly (p > 0.09) different when compared with non-vasospastic LTG patients (LTG-NV, 1.5 +/- 0.2, n = 15) but was significantly (p < 0.001) reduced in LTG-V and LTG-NV patients when compared with matched healthy control subgroups (2.3 +/- 0.2 and 2.4 +/- 0.3, respectively). IOP (mmHg) in LTG-V (13.3 +/- 0.4) and LTG-NV (13.2 +/- 0.5) patient groups was not significantly (p > 0.05) different when compared with each other, but was significantly (p < 0.05) lower when compared with matched control subgroups (15.0 +/- 0.3 and 15.2 +/- 0.4, respectively). Haemodynamic parameters were not significantly different from controls.

CONCLUSION

The abnormality in choroidal perfusion indicated by a reduction in OPA in all LTG patients is unrelated to the presence or absence of vasospasm.

Cold-induced acral vasospasm in migraine as assessed by nailfold video-microscopy: prevalence and response to migraine prophylaxis

In order to learn the prevalence of cold-induced vasospasm in migraine patients, blood cell velocity measurements of finger nailfold capillaries were performed in 58 consecutive patients suffering from migraine with and without aura. In 5 (8.6%) patients capillaroscopy could not be performed because of reduced nailfold transparency; 21 of the remaining 53 patients (39.6%) showed blood flow stop due to vasospasm under cold provocation. There was no significant difference (P = 0.69) in the occurrence of vasospastic reaction between migraine with (12 of 32 patients = 37.5%) and without (9 of 21 patients = 42.9%) aura. The clinical and capillaroscopic course under migraine prophylaxis was observed in 18 vasospastic patients. After sixteen weeks 14 patients showed good clinical improvement of their migraine. The vasospastic reaction persisted in only 1 patient. This patient and 3 others with abolished vasospasm were still suffering from migraine. These findings suggest that observing blood cell velocity noninvasively in nailfold capillaries under cold provocation could be useful for objectively monitoring the response to prophylactic treatment in migraine patients or for testing new potentially antimigraine drugs.

Increased capillary permeability in systemic sclerosis: help or hindrance?

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Synchronous measurements of blood pressure and red blood cell velocity in capillaries of human skin

We have devised a system for analyzing the temporal coherence of capillary pressure (CP) and capillary red blood cell velocity (CBV) variations in humans. The system is designed to measure human blood pressure in skin capillaries by direct cannulation while simultaneously measuring red blood cell velocity in the same capillary by video microscopy. The servo-nulling pressure measurement system allows the dynamic recording of capillary pressure with a flat frequency response of about 12 Hz. Computerized data acquisition is synchronized with the frame code of a U-matic video recorder, which records the capillaroscopic picture for later computerized off-line analysis of capillary red blood cell velocity. Measurements of simultaneously recorded CP and CBV in healthy volunteers show synchronized pulsation. Minimal pulsatile variations in CP values result in marked variations of CBV. In addition, minor fluctuations (3-4 cycles per minute) in CP are accompanied by marked changes in CBV. This system may help provide information about microvascular pathophysiology in skin diseases before and after treatment.

Local cold exposure test as therapy control in patients with Raynaud's phenomenon: comparison between laser Doppler fluxmetry and simultaneous red blood cell velocity measurements in nailfold capillaries

Synchronous measurement of laser Doppler flux (LDF) and capillary red blood cell velocity (CBV) was performed in adjacent areas of the same nailfold during a local cold stress test in 12 healthy controls (eight women and four men) and in 22 patients (17 women and seven men) with secondary Raynaud's phenomenon before and after treatment. Two questions were addressed: Are there any differences in the signal pattern between LDF and RBV? Is it possible to detect early on in therapy, before clinical benefit becomes obvious, whether a treatment is successful or not? Despite the fact that the resulting signal patterns recorded by these two techniques are widely compatible, certain differences could be observed. In healthy controls, decrease of values during cooling time and increase after cooling were more distinct in RBV than in LDF. Compared with control values, CBV and LDF in patients with Raynaud's phenomenon were lower. After cooling CBV took an average of 3 min to reach initial value again as compared with 40 s in healthy controls. During 4 min observation time, pretest values of LDF were not achieved again in patients, whereas it took 50 s in healthy controls. If, after a few days of vasospasmolytic therapy, test results improved or normalized, clinical symptoms subsided gradually during the next weeks. Clinical improvement was not observed in those patients in whom cutaneous blood flow remained decreased despite therapy. CBV indicated this more clearly than LDF. Duration of flow stop at the end of cooling showed a marked improvement in patients treated successfully. Discrepancies between CBV and LDF are interpreted as being due to LDF detecting other vessels in addition to the superficial, nutritional capillaries. LDF seemed to be a poor tool for evaluating the effect of treatment. Determination of CBV and flow stop duration during local cold exposure may help in early selection of the best treatment for a patient with Raynaud's phenomenon by predicting later possible clinical benefit.

Capillary microscopy is a diagnostic aid in patients with acral ischemia

The diagnosis of peripheral ischemic diseases is a challenge to the vascular specialist, since discrimination of the different entities on clinical grounds is not always clear. Capillary microscopy is a noninvasive diagnostic technique that can visualize in particular the morphology and perfusion of the digital capillaries. The authors investigated all 522 patients who were referred to the vascular laboratory over a six-year period, in an attempt to obtain more certainty about the diagnosis of their acral ischemic complaints. Patients with clinically manifest Raynaud's phenomenon and control subjects were compared to obtain differentiation criteria. Thus, capillary microscopy scored a sensitivity of 67%, a specificity of 84%, and an accuracy of 81% to detect Raynaud's phenomenon. A disturbed capillary morphology was virtually pathognomonic in Raynaud's disease secondary to systemic disorders (specificity 100%); the accuracy was but 74%. In 69% of the patients with clinically atypical acral ischemia, capillary microscopy yielded a diagnosis. Digital blood pressure measurements, however, appeared of no use in the diagnosis of Raynaud's phenomenon. Hence, capillary microscopy appears to be a useful aid in the diagnosis of acral ischemic syndromes.

The effect of rapid local cooling on human finger nailfold capillary blood pressure and blood cell velocity

1. The effect of a rapid local reduction in finger temperature on finger nailfold capillary blood pressure and blood cell velocity was investigated in healthy subjects. 2. Cooling was achieved by placing the finger into an adjustable copper cylindrical finger holder, which incorporated a Peltier element within its base; thus the entire finger from just distal to the nailfold to the interphalangeal joint was cooled. The Peltier element was cooled to 8 degrees C for 5 min. 3. Finger tip temperature was reduced to 76 +/- 12% of its resting value during cooling (28.8 +/- 4.8 degrees C (mean +/- S.D.) baseline versus 22.1 +/- 6.4 degrees C in the fifth minute of cooling, P = 0.012); this was accompanied by a reduction in capillary blood cell velocity similar to that described previously in cooling experiments using cold air (baseline median, 671 microns s-1 (range, 29-4421 microns s-1) versus median during cooling, 221 microns s-1 (range, 6.7-2579 microns s-1), P = 0.012). 4. The magnitude and timing of the capillary pressure response to cooling and recovery varied between individuals. In the group as a whole, there was no significant fall in capillary pressure during cooling (basal before cooling, 16.7 +/- 3.7 mmHg versus minimum during cooling, 15.1 +/- 3.5 mmHg, P = 0.12), whereas capillary pulse pressure amplitude was reduced (basal before cooling, 5.3 +/- 3.1 mmHg versus minimum during cooling, 3.7 +/- 2.6 mmHg, P = 0.028). 5. During the recovery phase, post cooling, both capillary pressure and capillary pulse pressure amplitude were markedly elevated compared to baseline or the cooling phase.(ABSTRACT TRUNCATED AT 250 WORDS)

The antioxidant butylated hydroxytoluene prevents early cholesterol-induced microcirculatory changes in rabbits

Microcirculation was studied during 10 wk in untreated rabbits (n = 13) and in rabbits treated with dietary addition of 1% cholesterol (n = 13), 1% cholesterol + 1% of the antioxidant BHT (butylated hydroxytoluene) (n = 11), or 1% BHT (n = 5). The studies were performed by direct intravital microscopic imaging of the left and right conjunctivae with the use of a stereo microscope and a high resolution television camera. Microvessel diameter, erythrocyte flow velocity, and microhemorheologic conditions were evaluated quantitatively via a computer-assisted digital image processing system. Significant and marked changes occurred in all the above variables as a consequence of cholesterol feeding. After 3 wk of feeding there was a dramatic decrease (approximately 30%) in blood flow velocity in arterioli of the third order (P < 0.0001), accompanied by aggregation of cells in 40-50% of the smaller conjunctival vessels (P < 0.0001). These changes were enhanced further during the following 7 wk of treatment. All the above changes in the microcirculation were markedly reduced by the addition of BHT treatment. The diameter of the above arterioli decreased in the purely cholesterol-fed group (P < 0.005), whereas this did not occur in the group fed both cholesterol and BHT. In rabbits fed BHT in the absence of cholesterol, there was no significant effect on any assessed microcirculatory variable. In conclusion, the results demonstrate that the antioxidant BHT prevented early cholesterol-induced microcirculatory changes. This prevention occurred in the absence of a reduction of blood lipid levels. The results provide strong support for the hypothesis that a considerable part of the effects on microcirculation in hypercholesterolemia may be due to cholesterol-induced oxidations and not to cholesterol itself. The results are discussed in relation to the previously demonstrated antiatherogenic effect of BHT and the possible use of antioxidants in the therapy and prophylaxis of atherosclerosis.

Quantitative nailfold capillary microscopy in cutaneous and systemic lupus erythematosus and localized and systemic scleroderma

Quantitative television microscopy of nailfold capillaries of the fingers was performed in 12 patients with cutaneous lupus erythematosus (six with discoid type and six with disseminated type), in six patients with localized scleroderma (two with circumscribed type, two with linear types, and two with atrophic type), in 10 patients with systemic lupus erythematosus, and in eight patients with systemic scleroderma. The following features were analyzed and compared with a control group (n = 15) of similar age: venous plexus visibility; density of capillaries; avascular fields; hemorrhages; giant capillaries; diameters of the transitional segment, the arterial, and the venous limbs; loop width; and flow stop caused by local cooling test. The patient groups with cutaneous lesions only showed no essential differences as compared with the controls. Patients with systemic scleroderma differed in almost every finding from the controls and from patients with localized scleroderma. Patients with systemic lupus erythematosus exhibited significant differences in several findings as compared with the controls and the cutaneous lupus erythematosus group, but there was overlap.

Transient corneal opacification induced by cold in Raynaud's disease

A 48-year-old man presented with longstanding complaints of transient blurring of vision on exposure to cold temperatures. A review of family history was noteworthy in that two of the patient's four sons and the patient's brother had similar complaints. All affected individuals had Raynaud's disease. Results of ophthalmic evaluation showed transient corneal opacities. Slit-lamp video photography under cold stress demonstrated conjunctival vascular changes consistent with Raynaud's phenomenon. An extensive work-up for systemic disease was otherwise negative. To the best of the authors' knowledge, anterior segment changes have not been described previously in idiopathic Raynaud's disease.

Digital artery calibre measurement--a new technique of assessing Raynaud's phenomenon

This study evaluated the use of a high frequency A-mode ultrasound scanner (CUTECH DM70) for monitoring the digital artery vasospasm of Raynaud's Phenomenon (RP). The technique was evaluated on 12 RP patients and 12 age and sex matched controls. The diameter of a single digital artery was measured in these subjects over a range of finger temperatures between 14-35 degrees C. The reproducibility of the measurements was assessed by repeating the procedure in two subjects (a control and an RP patient) on 5 separate days. The results confirmed that the technique is reproducible and monitored vasospasm occurring in all 12 RP patients. In the temperature range tested, none of the controls developed digital artery vasospasm. At finger temperatures greater than 25 degrees C the response to thermal stimuli of the digital arteries in RP patients and controls was similar. However, at temperatures less than 25 degrees C a marked vasoconstriction leading to complete digital artery closure was seen in the RP patients and not in the controls. This technique may prove useful in monitoring RP patients.

Reaction of capillary blood cell velocity in nailfold capillaries to nifedipine and ketanserin in patients with vasospastic disease

By using nailfold videomicroscopy in conjunction with local exposure of 60 s to cold air, the acute haemodynamic responses in capillary blood cell velocity 60 min after a single oral dose of 20 mg sustained-released nifedipine and 20 mg ketanserin were evaluated for each substance in 12 patients with vasospastic disease. The results obtained showed that the cold-induced flow stop duration was significantly (P less than 0.05) decreased and capillary blood cell velocity significantly (P less than 0.05) increased after local cooling. Systolic and diastolic blood pressure, heart rate and skin temperature did not differ significantly before and after treatment with either nifedipine or ketanserin. It is concluded that nifedipine and ketanserin are useful agents in the treatment of digital vasospastic disease. Furthermore, in vivo videomicroscopy is one of the few non-invasive and clinically useful direct methods for evaluating the effect of a drug on the microcirculation of normal and ischaemic skin areas.

Cutaneous blood flow responses in the forearms of Raynaud's patients induced by local cooling and intradermal injections of CGRP and histamine

1. The cutaneous responses of the forearm to local cold exposure and intradermal injection of CGRP and other vasoactive mediators were compared in primary Raynaud's sufferers and normal volunteers. 2. Skin responses in the forearm were measured in terms of erythema reddening and skin blood flow. Visual responses were recorded by tracing and then area calculated by computerised planimetry. Skin blood flow was measured using a laser Doppler blood flow meter. 3. Cooling (5-6 degrees C for 2 min) of a 1 cm2 area of the forearm caused a localised reactive hyperaemia response in normal volunteers, measured using the last Doppler blood flow meter. The peak response in Raynaud's patients was significantly smaller than that of normal volunteers. 4. The cutaneous responses of Raynaud's patients and normal volunteers to intradermal injections of CGRP, histamine and PGE2 were not significantly different. 5. The results suggest that Raynaud's sufferers do not exhibit a diminished response to CGRP in the cutaneous microvasculature and can respond normally to histamine with an axon reflex mediated flare.

Short- and long-term effect of nifedipine on the visual field in patients with presumed vasospasm

It is assumed that the ocular circulation may be involved in the vasospastic syndrome and patients with vasospasm have visual field defects that are neither ophthalmologically nor neurologically explainable. A retrospective study showed that 20 mg sustained-release nifedipine treatment given orally may be helpful in these cases. There was a marked short-term effect in cases with proven peripheral vasospasms but not in similar cases without such vasospasms. The study also showed that the effect could last for up to 12 months when 20 mg nifedipine was given twice daily but the long-term effect was slightly less than the short-term effect. A number of patients had to discontinue nifedipine treatment due to side-effects.

Capillary blood cell velocity in finger nailfold: characteristics and reproducibility of the local cold response

The characteristics and reproducibility of nailfold capillary blood cell velocity (CBV) of the local cold response was evaluated in 30 cases by video-microscopy using a flying-spot technique. CBV, as well as flow stop duration during cooling, from a first and second test was significantly (P less than 0.05) reproducible, whether or not the test was repeated after 60 min or after an interval of 12 weeks. Because of interindividual variations in rest CBV, and a better reproducibility of the flow stop duration, this last parameter is more useful in clinical practice for follow-up evaluations of the local cold response test. The usefulness of the flying-spot generator for rapid and accurate measurement of CBV in finger nailfold capillaries is demonstrated in normal subjects and patients with primary Raynaud syndrome during a local cooling test.

Do vasospasms provoke ocular diseases?

Vasospasms in the eye are often combined with digital vasospasms, as can be diagnosed with a nailfold capillaroscopic local cooling test. In 16 patients with a history of cold hands and feet the presence of peripheral vasospasms without any underlying disease was demonstrated by means of nailfold video-capillaroscopy. These patients showed the phenomenologic diagnosis of low-tension glaucoma with visual field defects characteristic of glaucoma even though intraocular pressure above 21 mmHg was excluded. The visual field defects were not homonymous, indicating a prechiasmal location of the vascular disturbance. Ocular vasospasms cause visual field damage that can be aggravated or provoked by cooling one hand in cold water and that often improves after treatment with the calcium channel blocker nifedipine. The results suggest that vasospasms not only are present in Raynaud's disease, migraine, and Prinzmetal's variant angina but also may be an important factor in the genesis of low-tension glaucoma. This is a new finding and may be related to a general vasospastic syndrome.