Evidence for an abnormal peripherally mediated vascular response to temperature in Raynaud's phenomenon

[Functional vascular acrosyndromes]

Vascular acrosyndromes are characterized by sparse, uniform clinical manifestations and a variety of possible pathomechanisms. The present article focuses on the functional entities. Raynaud phenomenon is based on cold- or stress-induced vasospasms of acral arteries. It is defined by the color changes of the skin, in the typical case white-blue-red (tricolore). The long fingers are most commonly affected. The etiology is unknown, and the pathophysiology is poorly understood. A distinction is made between primary and a secondary Raynaud phenomenon. The most important underlying diseases include collagenosis, primarily systemic sclerosis, and malignancies; furthermore, medications and drugs may promote vasospasm. Treatment is aimed at preventing or breaking the vasospasm, but has been only partially effective in doing so. Acrocyanosis is a vasospastic dystonic acral disorder that results in permanent reddish-livid discoloration, especially of the hands and feet. Secondary forms occur in collagenosis, malignancies, and myelodysplastic syndromes. The etiology and pathophysiology are virtually unknown. Targeted pharmacological intervention is not possible. Unlike all other vascular acrosyndromes, erythromelalgia is characterized by hyperemia. The primary form is a genetic sodium channelopathy, while secondary forms include malignancies, connective tissue diseases, and myelodysplastic syndromes. The symptoms are often distressing and disabling. Therapy requires a multimodal approach that includes both nonpharmacological and pharmacological strategies. Close interdisciplinary collaboration is essential for the management of this disease.

Normal-tension glaucoma: Current concepts and approaches-A review

Normal tension glaucoma (NTG) has remained a challenging disease. We review, from an epidemiological perspective, why we should redefine normality, act earlier at lower pre-treatment intraocular pressure (IOP) level, and the role of ocular perfusion pressures, noting that perfusion is affected by defective vascular bed autoregulation and endothelial dysfunction. The correlation of silent cerebral infarcts (SCI) and NTG may indicate that NTG belongs to a wider spectrum of small vessel diseases (SVD), with its main pathology being also on vascular endothelium. Epidemiological studies also suggested that vascular geometry, such as fractal dimension, may affect perfusion efficiency, occurrence of SCI, SVD and glaucoma. Artificial intelligence with deep learning, may help predicting NTG progression from vascular geometry. Finally, we review latest evidence on the role of minimally-invasive glaucoma surgery, lasers, and newer drugs. We conclude that IOP is not the only modifiable risk factors as, many vascular risk factors are readily modifiable.

Nonarteriosclerotic vascular disease

Thromboangiitis obliterans, or Buerger disease, is a chronic nonatherosclerotic endarteritis manifesting as inflammation and thrombosis of distal extremity small and medium-sized arteries resulting in relapsing episodes of distal extremity ischemia. Takayasu arteritis is a rare syndrome characterized by inflammation of the aortic arch, pulmonary, coronary, and cerebral vessels, presenting with cerebrovascular symptoms, myocardial ischemia, or upper extremity claudication in young, often female, patients. Kawasaki disease is a small- and medium-vessel acute systemic vasculitis of young children, with morbidity and mortality stemming from coronary artery aneurysms. Microscopic polyangiitis, Churg-Strauss syndrome, and Wegener granulomatosis are systemic small-vessel vasculitides, affecting arterioles, capillary beds and venules, and each presenting with variable effects on the pulmonary, renal and gastrointestinal systems.

Coronary atherosclerosis using computed tomography coronary angiography in patients with systemic sclerosis

BACKGROUND

Impaired coronary artery reserve has previously been demonstrated in patients with systemic sclerosis (SSc). Both micro- and macrovascular factors are probably contributory to the underlying pathogenesis.

OBJECTIVES

To examine the frequency of coronary atherosclerosis in a series of SSc patients by computed tomography coronary angiography (CTCA), a less invasive method than conventional coronary angiography, the current gold standard in the detection of coronary atherosclerosis, and to explore its clinical associations.

METHODS

Nineteen consecutive SSc patients [six with diffuse (dSSc) and 13 with limited disease (lSSc)] with disease duration of >or= 3 years were recruited. Coronary calcium score and contrast angiography were examined by CT scan. Conventional cardiovascular factors and inflammatory markers were measured and correlated with CT findings.

RESULTS

The mean+/-SD age of these patients was 52.5+/-12.5 years with median disease duration of 12.5 years. Six (31.6%) patients were found to have coronary artery calcification (calcium score 13-2008). Coronary calcium was detected in one dSSc patient but contrast angiography was not performed because of interference from an in situ implantable cardiac device. Some parts of the coronary arteries were not assessable in two patients who had ectopic cardiac rhythm. Five lSSc patients had calcified plaques causing variable coronary luminal stenosis. All patients were asymptomatic. Patients with abnormal CTCA findings were more likely to be older (p < 0.001) and were less likely to have serum anti-Scl70 antibodies (p = 0.003) than those without, after Bonferroni correction.

CONCLUSIONS

Coronary atherosclerosis is not uncommon in asymptomatic SSc patients. CTCA is a convenient and non-invasive method for studying coronary atherosclerosis.

Endothelial dysfunction in glaucoma

Glaucoma is a group of ocular diseases characterized by optic neuropathy associated with loss of the retinal nerve fibre layer and re-modelling of the optic nerve head, and a subsequent particular pattern of visual field loss. Increased intraocular pressure is the most important risk factor for the disease, but the pathogenesis of glaucoma is not monofactorial. Among other factors, ischaemia and vascular dysregulation have been implicated in the mechanisms underlying glaucoma. The vascular endothelium plays an important role in the regulation of ocular blood flow and pathological alterations of vascular endothelial cells may induce ischaemia and dysregulation. The present review summarizes our current evidence of endothelial dysfunction in glaucoma. This is of interest because endothelial dysfunction is a good prognostic factor for progression in several diseases. Although such data are lacking for glaucoma, endothelial dysfunction may provide an attractive target for therapeutic intervention in open-angle glaucoma and other vascular disorders of the eye.

Abnormal microvascular response is localized to the digits in patients with systemic sclerosis

OBJECTIVE

To investigate the hypothesis that cutaneous microvascular perfusion of the dorsum of the hand (in response to local heating) and distal phalanx (in response to occlusion) is impaired in patients with systemic sclerosis (SSc) compared with healthy controls.

METHODS

Twenty-nine patients with SSc and 29 control subjects were recruited. Perfusion was monitored using novel dual-wavelength laser Doppler imaging, allowing measurement of both smaller (capillaries) and larger (thermoregulatory) vessels. Postacclimatization, a baseline dorsum scan (red or green wavelength) was performed. A heating pad was placed on the dorsum (total stimulus time 6 minutes at 34-40 degrees C), and following removal of the pad, baseline wavelength scans were performed until perfusion returned to baseline values. This was then repeated for the second wavelength. The maximum perfusion increase due to heating (PEAK1) and area under the perfusion-time curve (AUC) were determined. In addition, scans (both wavelengths) of the index finger were performed prior to and during 2 minutes of suprasystolic occlusion, and the response upon occlusion release was monitored with single-point laser Doppler. The decrease in perfusion due to occlusion (from preocclusion baseline values) (%DECREASE) and the maximum increase (from baseline perfusion values under occlusion) in hyperemic perfusion upon removal of occlusion (PEAK/OCC) were calculated.

RESULTS

PEAK1 and AUC values were not significantly different between patients and controls, as assessed with either wavelength. A significant difference between groups was found in the %DECREASE values with the green, but not the red, wavelength. A significant between-group difference was also found in PEAK/OCC values, using both wavelengths.

CONCLUSION

This study suggests that SSc has no effect on microvascular perfusion in the dorsum of the hand, and that the abnormal microvascular response is localized to the digits, affecting both smaller and larger vessels.

A two-stage, genome-wide screen for susceptibility loci in primary Raynaud's phenomenon

OBJECTIVE

To identify chromosomal regions containing genes involved in the susceptibility to primary Raynaud's phenomenon (RP).

METHODS

Six extended families with multiple individuals affected with primary RP (n = 37) were examined for linkage in a 2-stage, whole-genome screen, using a total of 298 microsatellite markers.

RESULTS

Multipoint, nonparametric linkage analysis identified 5 areas of possible linkage, with a nominal level of significance of P < or = 0.05. Analysis of a finer map of markers in these regions defined the regions of linkage as 21.4 cM on 6q13-6q23.3 (D6S261; P = 0.0004), 10.2 cM on 7p22-7p15 (D7S664; P = 0.014), 1.6 cM on 9p23-9p22 (D9S156; P = 0.0075), 5.1 cM on 17p13.1-17p12 (D17S1791; P = 0.036), and 11.8 cM on Xp11.4-Xp11.23 (DXS8054; P = 0.006). Three potential candidate genes map to these regions: the beta subunit of the muscle acetylcholine receptor and the serotonin 1B and 1E receptors.

CONCLUSION

These results provide evidence of the presence and location of genes that are involved in the genetic susceptibility to primary RP.

Posturally induced leg vasoconstrictive responses: relationship to standing duration, impedance and volume changes

Shifting legs to a gravity-dependent position provokes a physiological vasoconstrictive response that forms the basis of several diagnostic tests based on initial (< 5 min) blood perfusion decreases. However, it is not known if responses are maintained over longer duration and if they depend on the volume shifted to the limb during the manoeuvre. These issues were investigated by measurements of blood perfusion changes on foot and ankle (laser Doppler) and below-knee volume and impedance changes induced by 30 min of standing in 10 healthy volunteers. Initial perfusion decreases were 66.4% +/- 2.6% and 49.3% +/- 3.8% for ankle and foot dorsum, respectively, and were fully maintained during sustained standing without evidence of 'vasodilator escape'. Response magnitudes were not dependent on leg volume changes using geometric or impedance measures. A close correlation (r2 = 0.78) between impedance and volume changes suggests the former as a useful way of assessing dynamic limb volume changes. Sustained vasoconstrictive responses make it unlikely that extending the duration of such tests would offer more, diagnostic information than is currently available.

Increased prevalence of symptomatic macrovascular disease in systemic sclerosis

OBJECTIVES

To determine the prevalence of symptomatic macrovascular disease, as defined by the World Health Organisation questionnaire for intermittent claudication, in patients with systemic sclerosis (SSc), and to compare the prevalence in this population with a cross sectional population study group reported in the Edinburgh Artery Study (EAS).

METHODS

A group of 53 patients with a diagnosis of limited or diffuse systemic sclerosis were identified from our register. They were asked to complete the WHO questionnaire to establish the presence or absence of intermittent claudication. In addition, each patient's case notes were reviewed to establish the existence of definite peripheral vascular disease and to determine their risk factor profile.

RESULTS

Forty six patients responded to the questionnaire, giving a response rate of 87%. Intermittent claudication was found in 10 SSc patients (21.7%) according to the questionnaire (two with diffuse and eight with limited SSc), compared with a prevalence rate of 4.6% for claudication in the EAS. Three SSc patients experienced clinical events attributable to occlusion of a major artery proven on angiography. Four patients had hypertension, there were three current and four ex-smokers, and two had increased total cholesterol. None of these patients had diabetes.

CONCLUSIONS

This study demonstrated a greater prevalence of macrovascular disease in patients with SSc than had been found in a neighbouring population.

Evaluation of skin blood flow by laser Doppler flowmetry

Laser Doppler flowmetry is an excellent noninvasive technique for the measurement of cutaneous microcirculation. The list of applications of laser Doppler flowmetry in dermatology is long. It can be applied to monitor inflammation caused by various drugs, chemicals, and allergens related to blood flow. To measure certain inflammatory reactions a combination of other bioengineering measurements is desirable. Flaps can be monitored, and burn depth measured by laser Doppler flowmetry. Through blood flow measurement, the pathophysiology of various skin diseases can be verified and certain treatments can be partially monitored. Although it is not as directly applicable to daily clinical practice, except in a few cases, laser Doppler flowmetry is a very useful technique in various kinds of dermatologic research.

Raynaud's disease: pathophysiology, diagnosis, and treatment

Raynaud's disease is a common vasospastic disorder affecting the digits of both hands. Women are most commonly affected. This disorder occurs in two forms: Raynaud's disease and Raynaud's phenomenon. Raynaud's phenomenon is associated with a secondary etiology, most commonly scleroderma. Symptoms may precede the onset of connective tissue disease by a number of years. The pathophysiology, differential diagnosis, recommendations for referral, and treatment of Raynaud's disease are presented. A protocol for use by the nurse practitioner in the primary care setting is provided.

Raynaud's syndrome, an enigma after 130 years

The recent literature concerning Raynaud's syndrome is reviewed. Raynaud's syndrome is as common as hypertension and diabetes. In spite of its generally benign character, it causes a lot of discomfort to individuals and sickness absenteeism to society, especially in the colder regions of the world. The etiology remains an enigma 130 years after its first description, perhaps even more so than ever before, the many new theories proposed in the literature. Clearly, in a condition where seventy different etiologic theories are advocated, the culprit lesion is obviously missing, or there is not a culprit lesion but an accumulation of conditions having nothing in common but a few symptoms. Moreover a Raynaud attack may result, not from a single event, but from a cascade of events, just as, for example, hemostasis does. Controversy about diagnosis exists all over. For example, how does one make a diagnosis? Patient history has been considered unreliable. A standardized cold test, though highly reproducible in the authors' hands, is far from common property. Raynaud's syndrome is a condition for which thirty-eight therapies have been advocated in the last three years, but the curative answer is still to come.