Calcium channel blockers for primary Raynaud's phenomenon

Raynaud's Phenomenon: A Current Update on Pathogenesis, Diagnostic Workup, and Treatment

Raynaud's phenomenon (RP) is a condition characterized by episodic, excessive vasoconstriction in the fingers and toes, triggered by cold or stress. This leads to a distinctive sequence of color changes in the digits. Pallor indicates reduced blood flow due to oxygen deprivation, while erythema appears as reperfusion. RP can be primary, with no identifiable underlying cause, or secondary, associated with other conditions. These conditions include autoimmune diseases, most commonly systemic sclerosis, vascular diseases; and neurological conditions. While the exact cause of RP remains unclear, genetic and hormonal (estrogen) factors are likely contributors. The pathogenesis of RP involves a complex interaction between the vascular wall, nerves, hormones, and humoral factors, disrupting the balance between vasoconstriction and vasodilation. In primary RP, the vascular abnormalities are primarily functional. However, in secondary RP, both functional and structural components occur in blood vessels. This explains why digital tissue damage frequently occurs in secondary RP but not primary RP. Diagnosis of RP is primarily clinical. Recent advancements in imaging techniques have aided in diagnosis and monitoring, but nail fold capillaroscopy remains the gold standard for distinguishing between primary and secondary RP. If there are signs of acute ischemic injury, vascular imaging, particularly preoperatively, is crucial to rule out other vaso-occlusive conditions. Management of RP focuses on alleviating symptoms and preventing tissue damage. Vasodilator medications are the first-line treatment when general measures like warmth and stress management are not sufficient. Dihydropyridine calcium channel blockers (CCBs), such as nifedipine, are commonly used for vasodilation. Phosphodiesterase-5 inhibitors and prostaglandin analogs are alternative options for patients who do not respond to CCBs or have ischemic tissue damage. Bosentan, an endothelin-1 receptor antagonist, has shown effectiveness in treating and preventing digital ulcers, especially in patients with multiple ulcers. For severe cases, botulinum toxin injections or sympathectomy surgery can be used to control RP symptoms. However, botulinum toxin injections require repeated administration, and sympathectomy's long-term effectiveness is uncertain. Fat grafting is a promising surgical therapy for promoting healing and preventing tissue injury.

Efficacy of Radiofrequency Thermocoagulation of the Thoracic Sympathetic Nerve versus Chemical Excision in Pain Caused by Raynaud's Disease

Objective

To investigate the effectiveness and safety of computed tomography (CT)-guided radiofrequency thermocoagulation (RFTC) of the thoracic sympathetic nerve versus chemical resection (CTS) for the treatment of pain caused by Raynaud's disease.

Methods

Patients who underwent CTS or thoracic sympathetic nerve RFTC between March 2012 and March 2021 were enrolled in this retrospective study. There were 28 cases in the alcohol group (Group A) and 44 in the radiofrequency group (Group R). Visual analog scores (VAS) were collected from patients at different time points, as well as preoperative and postoperative finger end perfusion index (PI) and hand temperature (T). The efficiency, postoperative recurrence rate, complications, and improvement in postoperative quality of life were observed in both groups.

Results

Pain scores at different follow-up times after surgery decreased in both groups compared to the preoperative period (P < 0.05). Postoperative T and PI were higher in both groups than preoperatively all (P < 0.05). The recurrence rate was higher in the R group than in the A group. Postoperative complications were observed in 13.6% and 25% of patients in groups R and A, respectively. Meanwhile, the postoperative quality of life improved in both groups, but the radiofrequency (RF) group was better than the alcohol group in terms of improvement in quality of life (P < 0.05).

Conclusion

Both CT-guided CTS and RFTC of the thoracic sympathetic nerve provided good treatment outcomes. However, the RF group was superior to the alcohol group in terms of complication rate and quality of life improvement.

Raynaud's Phenomenon with Focus on Systemic Sclerosis

Raynaud’s phenomenon is a painful vascular condition in which abnormal vasoconstriction of the digital arteries causes blanching of the skin. The treatment approach can vary depending on the underlying cause of disease. Raynaud’s phenomenon can present as a primary symptom, in which there is no evidence of underlying disease, or secondary to a range of medical conditions or therapies. Systemic sclerosis is one of the most frequent causes of secondary Raynaud’s phenomenon; its appearance may occur long before other signs and symptoms. Timely, accurate identification of secondary Raynaud’s phenomenon may accelerate a final diagnosis and positively alter prognosis. Capillaroscopy is fundamental in the diagnosis and differentiation of primary and secondary Raynaud’s phenomenon. It is helpful in the very early stages of systemic sclerosis, along with its role in disease monitoring. An extensive range of pharmacotherapies with various routes of administration are available for Raynaud’s phenomenon but a standardized therapeutic plan is still lacking. This review provides insight into recent advances in the understanding of Raynaud’s phenomenon pathophysiology, diagnostic methods, and treatment approaches.

Repurposing Cilostazol for Raynaud's Phenomenon

Raynaud 's Phenomenon (RP) results from exaggerated cold-induced vasoconstriction. RP patients suffer from vasospastic attacks and compromised digital blood perfusion leading to a triple color change at the level the fingers. Severe RP may cause ulcers and threaten tissue viability. Many drugs have been used to alleviate the symptoms of RP. These include calcium-channel blockers, cGMP-specific phosphodiesterase type 5 inhibitors, prostacyclin analogs, and angiotensin receptor blockers. Despite their variety, these drugs do not treat RP but rather alleviate its symptoms. To date, no drug for RP has been yet approved by the U.S Food and Drugs Administration. Cilostazol is a selective inhibitor of phosphodiesterase-III, originally prescribed to treat intermittent claudication. Owing to its antiplatelet and vasodilating properties, cilostazol is being repurposed as a potential drug for RP. This review focuses on the different lines of action of cilostazol serving to enhance blood perfusion in RP patients.

Vasodilators for primary Raynaud's phenomenon

BACKGROUND

Numerous agents have been suggested for the symptomatic treatment of primary Raynaud's phenomenon. Apart from calcium channel blockers, which are considered to be the drugs of choice, evidence of the effects of alternative pharmacological treatments is limited. This is an update of a review first published in 2008.

OBJECTIVES

To assess the effects of drugs with vasodilator effects on primary Raynaud's phenomenon as determined by frequency, severity, and duration of vasospastic attacks; quality of life; adverse events; and Raynauds Condition Score.

SEARCH METHODS

The Cochrane Vascular Information Specialist searched the Cochrane Vascular Specialised Register, CENTRAL, MEDLINE, Embase, and CINAHL databases, and the World Health Organization International Clinical Trials Registry Platform and the ClinicalTrials.gov trial register to November 16, 2020.

SELECTION CRITERIA

We included randomized controlled trials evaluating effects of oral, intravenous, and topical formulations of any drug with vasodilator effects on subjective symptoms, severity scores, and radiological outcomes in primary Raynaud's phenomenon. Treatment with calcium channel blockers was not assessed in this review, nor were these agents compared.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, assessed studies using the Cochrane "Risk of bias" tool, and extracted study data. Outcomes of interest included frequency, severity, and duration of attacks; quality of life (QoL); adverse events (AEs); and the Raynaud Condition Score (RCS). We assessed the certainty of the evidence using GRADE.

MAIN RESULTS

We identified seven new studies for this update. In total, we included 15 studies involving 635 participants. These studies compared different vasodilators to placebo. Individual studies used different methods and measures to report different outcomes. Angiotensin-converting enzyme (ACE) inhibitors Combining data from three studies revealed a possible small increase in the frequency of attacks per week after treatment (captopril or enalapril) compared to placebo (mean difference [MD] 0.79, 95% confidence interval [CI] 0.43 to 1.17; low-certainty evidence). There was no evidence of a difference between groups in severity of attacks (MD -0.17, 95% CI -4.66 to 4.31; 34 participants, 2 studies; low-certainty evidence); duration of attacks (MD 0.54, 95% CI -2.42 to 1.34; 14 participants, 1 study; low-certainty evidence); or AEs (risk ratio [RR] 1.35, 95% CI 0.67 to 2.73; 46 participants, 3 studies; low-certainty evidence). QoL and RCS were not reported. Alpha blockers Two studies used alpha blockers (buflomedil or moxisylyte). We were unable to combine data due to the way results were presented. Buflomedil probably reduced the frequency of attacks compared to placebo (MD -8.82, 95% CI -11.04 to -6.60; 31 participants, 1 study; moderate-certainty evidence) and may improve severity scores (MD -0.41, 95% CI -0.62 to -0.30; moderate-certainty evidence). With moxisylyte, investigators reported fewer attacks (P < 0.02), less severe symptoms (P < 0.01), and shorter duration of attacks, but the clinical relevance of these results is unclear. No evidence of a difference in AEs between buflomedil and placebo groups was noted (RR 1.41, 95% CI 0.27 to 7.28; 31 participants, 1 study; moderate-certainty evidence). More AEs were observed in participants in the moxisylyte group than in the placebo group. Prostaglandin/prostacyclin analogues One study compared beraprost versus placebo. There was no evidence of benefit for frequency (MD 2.00, 95% CI -0.35 to 4.35; 118 participants, low-certainty evidence) or severity (MD -0.06, 95% CI -0.34 to 0.22; 118 participants, low-certainty evidence) of attacks. Overall, more AEs were noted in the beraprost group (RR 1.59, 95% CI 1.05 to 2.42; 125 participants; low-certainty evidence). This study did not report on duration of attacks, QoL, or RCS. Thromboxane synthase inhibitors One study compared a thromboxane synthase inhibitor (dazoxiben) versus placebo. There was no evidence of benefit for frequency of attacks (MD 0.8, 95% CI -1.81 to 3.41; 6 participants; very low-certainty evidence). Adverse events were not reported in subgroup analyses of participants with primary Raynaud's phenomenon, and the study did not report on duration of attacks, severity of symptoms, QoL, or RCS. Selective serotonin reuptake inhibitors One study compared ketanserin with placebo. There may be a slight reduction in the number of attacks per week with ketanserin compared to placebo (MD -14.0, 95% CI -27.72 to -0.28; 41 participants; very low-certainty evidence) and reduced severity score (MD -133.00, 95% CI -162.40 to -103.60; 41 participants; very low-certainty evidence). There was no evidence that ketanserin reduced the duration of attacks (MD -4.00, 95% CI -14.82 to 6.82; 41 participants; very low-certainty evidence), or that AEs were increased in either group (RR 1.54, 95% CI 0.89 to 2.65; 41 participants; very low-certainty evidence). This study did not report on QoL or RCS. Nitrate/nitrate derivatives Four studies compared topical treatments of nitroglycerin or glyceryl trinitrate versus placebo, each reporting on limited outcomes. Meta-analysis demonstrated no evidence of effect on frequency of attacks per week (MD -1.57, 95% CI -4.31 to 1.17; 86 participants, 2 studies; very low-certainty evidence). We were unable to pool any data for the remaining outcomes. Phosphodiesterase inhibitors Three studies compared phosphodiesterase inhibitors (vardenafil, cilostazol or PF-00489791) to an equivalent placebo. Results showed no evidence of a difference in frequency of attacks (standardized MD [SMD] -0.05, 95% CI -6.71 to 6.61; 111 participants, 2 studies; low-certainty evidence), severity of attacks (MD -0.03, 95% CI -1.04 to 0.97; 111 participants, 2 studies; very low-certainty evidence), duration of attacks (MD -1.60, 95% CI -7.51 to 4.31; 73 participants, 1 study; low-certainty evidence), or RCS (SMD -0.8, 95% CI -1.74 to 0.13; 79 participants, 2 studies; low-certainty evidence). Study authors reported that 35% of participants on cilostazol complained of headaches, which were not reported in the placebo group. PF-00489791 caused 34 of 54 participants to experience AEs versus 43 of 102 participants receiving placebo (RR 1.49). Headache was most common, affecting 14 participants (PF-00489791) versus nine participants (placebo).

AUTHORS' CONCLUSIONS

The included studies investigated several different vasodilators (topical and oral) for treatment of primary Raynaud's phenomenon. Small sample sizes, limited data, and variability in outcome reporting yielded evidence of very low to moderate certainty. Evidence is insufficient to support the use of vasodilators and suggests that vasodilator use may even worsen disease.

Sudden onset peripheral visual deficit secondary to retinal artery spasm in Raynaud's phenomenon

A 32-year-old doctor, who has a medical history of primary Raynaud's disease and previous scotomas, presented to eye clinic with sudden onset blurring of vision (infero-nasally) with no other associated symptoms. The patient had good visual acuity bilaterally (6/6) and no anterior chamber activity or conjunctival hyperaemia. Findings consistent with a nerve fibre layer infarct were noted in the right eye, with unremarkable examination of the left eye. Optical coherence tomography (OCT) and optical coherence tomography angiography (OCTA) images were obtained, which showed an area of capillary shut down in keeping with a nerve fibre layer lesion. Previous literature pertaining to similar symptoms is sparse with symptoms such as migraines, epilepsy and visual loss being stated. This case provides further evidence of Raynaud's associated retinal artery spasm, with complete resolution at 4 weeks. We also demonstrate the accessibility of OCT and more importantly OCTA for investigation of sudden onset visual deficit.

Finger blood flow after the cold challenge with primary Raynaud's syndrome: a case report

Background 

Raynaud’s syndrome is a commonly encountered disorder. The relationship between the grade of Raynaud’s phenomenon and severity of vasoconstriction is unclear. Recently, various methods including colour Doppler ultrasonography have been used for assessment of vascularity of the extremities including fingers.

Case summary 

A 53-year-old man had a 6-year history of Raynaud’s phenomenon with typical tri-coloured changes proceeding from white, blue to red and slight pain and slight paresthaesia in the fingers of both hands when his fingers were exposed to cold. He was diagnosed with primary Raynaud’s syndrome. After treatment with the calcium channel blocker amlodipine (5 mg once daily), a cold challenge did not induce Raynaud’s phenomenon on the fingers in the present patient. After the cold challenge, colour Doppler ultrasonography showed that vascularity was markedly decreased or was absent, whereas there was little difference in skin colour of the fingers.

Discussion 

In Raynaud's phenomenon, vasospasm may occur even if the symptoms are well-controlled with a calcium channel blocker. It is unlikely that clinical symptoms in patients with Raynaud’s syndrome always reflect the severity of vasoconstriction in their fingers.

Raynaud's phenomenon

Raynaud's phenomenon (RP) is common, affecting approximately 5% of the population, and is important to the rheumatologist because it is often the presenting symptom of connective tissue disease, especially of systemic sclerosis (SSc)-spectrum disorders. RP therefore provides a window of opportunity for early diagnosis. When RP is associated with SSc it is particularly challenging to treat. This review begins with a discussion of some of the recent advances in our understanding of the pathogenesis of RP: it is through increased understanding of the complex pathophysiology of RP that we are most likely to develop new therapies. The following questions are then addressed (with three clinical scenarios demonstrating key principles of assessment and management): 1. How can we predict underlying connective tissue disease in the patient presenting with Raynaud's? 2. How can we measure severity of Raynaud's? 3. What are the latest advances in treatment of connective tissue disease-related digital vasculopathy?

A case report of severe nasal ischemia from cold agglutinin disease and a novel treatment protocol including HBOT

Cold agglutinin disease (CAD) is a rare condition leading to blood agglutination and autoimmune hemolytic anemia. Cutaneous ischemia resulting from CAD in the head and neck is uncommon. Treatment regimens and outcomes vary widely in the literature and no clear protocol exists. This manuscript describes a patient with CAD who developed severe ischemia of the nose that resolved completely without sequellae following a medical regimen of aspirin, low molecular weight heparin, nitroglycerin ointment and hyperbaric oxygen therapy (HBOT). To our knowledge, this is the first reported case where nitroglycerin ointment or HBOT was successfully employed in the treatment of this complication.

Raynaud's phenomenon

Raynaud's phenomenon can be either primary (idiopathic) or secondary to underlying disease including systemic sclerosis. Primary Raynaud's phenomenon is very common, affecting approximately 3%-5% of the general population. Although much rarer, systemic sclerosis-related Raynaud's phenomenon can be particularly severe, progressing to digital ulceration in approximately 50% of patients. Raynaud's phenomenon can have a major impact on quality of life. This review has a focus on the systemic sclerosis-related Raynaud's phenomenon (which is the most researched form of Raynaud's phenomenon and probably the most challenging to treat) and on recent advances. Epidemiology (including transition from 'isolated' to systemic sclerosis-related Raynaud's phenomenon), pathogenesis, diagnosis and assessment are discussed, followed by the treatment of both 'uncomplicated' and 'complicated' Raynaud's phenomena (i.e. Raynaud's phenomenon which has progressed to digital ulceration and/or critical ischaemia). Finally, some of the major challenges for the next 5-10 years are highlighted.

Behaviour change interventions for the management of Raynaud's phenomenon: a systematic literature review

OBJECTIVES

Raynaud's phenomenon (RP) is a significant cause of morbidity. Vasodilator medications cause unwanted adverse effects, with behavioural and lifestyle changes forming the mainstay of self-management; this is difficult to implement successfully. The objectives of this study were to evaluate the efficacy of behaviour change interventions for RP and identify learning points for future treatment development.

DESIGN

Systematic literature review and narrative synthesis of findings.

DATA SOURCES

EMBASE, MEDLINE, Cochrane and PsycINFO were searched for eligible studies on 22 August 2017.

ELIGIBILITY CRITERIA

Randomised controlled trials (RCTs) of behaviour change interventions with at least one control comparator arm.

DATA EXTRACTION AND SYNTHESIS

Study selection, data extraction and risk of bias were assessed independently by two reviewers, reaching consensus with a third when necessary. Primary outcomes of interest included severity/impact, frequency and duration of RP episodes, pain, disability, adverse events and study withdrawal.

RESULTS

Of 638 articles retrieved, eight studies fulfilled criteria for inclusion. Biofeedback was the active behaviour change treatment arm for seven studies, with one study reporting a behavioural intervention. Studies were published 1978-2002; six were USA-based studies, one German and one Swedish. Using Cochrane Risk of Bias assessment, studies were assessed to be overall at high risk of bias, with the exception of one large RCT. The total sample included 495 participants (study median=29), with a median age of 39.5 years and preponderance towards females (73%). Five studies reported significant effects in primary outcomes of interest; however, due to missing data, relative efficacy of interventions could not be reliably assessed.

CONCLUSIONS

There is no evidence to support or refute claims of the efficacy of behaviour change interventions for the management of RP. There remains a strong case for developing and testing behaviour change interventions that focus on self-management; however, theoretical development and advancement in trial quality is imperative to underpin future work.

PROSPERO REGISTRATION NUMBER

CRD42017049643.

A Multicenter Study of the Validity and Reliability of Responses to Hand Cold Challenge as Measured by Laser Speckle Contrast Imaging and Thermography: Outcome Measures for Systemic Sclerosis-Related Raynaud's Phenomenon

OBJECTIVE

Reliable and objective outcome measures to facilitate clinical trials of novel treatments for systemic sclerosis (SSc)-related Raynaud's phenomenon (RP) are badly needed. Laser speckle contrast imaging (LSCI) and thermography are noninvasive measures of perfusion that have shown excellent potential. This multicenter study was undertaken to determine the reliability and validity of a hand cold challenge protocol using LSCI, standard thermography, and low-cost cell phone/mobile phone thermography (henceforth referred to as mobile thermography) in patients with SSc-related RP.

METHODS

Patients with RP secondary to SSc were recruited from 6 UK tertiary care centers. The patients underwent cold challenge on 2 consecutive days. Changes in cutaneous blood flow/skin temperature at each visit were imaged simultaneously using LSCI, standard thermography, and mobile thermography. Measurements included area under the curve (AUC) for reperfusion/rewarming and maximum blood flow rate/skin temperature after rewarming (MAX). Test-retest reliability was assessed using intraclass correlation coefficients (ICCs). Estimated latent correlations (estimated from multilevel models, taking values between -1 and 1; denoted as rho values) were used to assess the convergent validity of LSCI and thermography.

RESULTS

In total, 159 patients (77% with limited cutaneous SSc) were recruited (84% female, median age 63.3 years). LSCI and standard thermography both had substantial reliability, with ICCs for the reperfusion/rewarming AUC of 0.67 (95% confidence interval [95% CI] 0.54, 0.76) and 0.68 (95% CI 0.58, 0.80), respectively, and ICCs for the MAX of 0.64 (95% CI 0.52, 0.75) and 0.72 (95% CI 0.64, 0.81), respectively. Very high latent correlations were present for the AUCs of LSCI and thermography (ρ = 0.94; 95% CI 0.87, 1.00) and for the AUCs of standard and mobile thermography (ρ = 0.98; 95% CI 0.94, 1.00).

CONCLUSION

This is the first multicenter study to examine the reliability and validity of cold challenge using LSCI and thermography in patients with SSc-related RP. LSCI and thermography both demonstrated good potential as outcome measures. LSCI, standard thermography, and mobile thermography had very high convergent validity.

Efficacy and Safety of Selexipag in Adults With Raynaud's Phenomenon Secondary to Systemic Sclerosis: A Randomized, Placebo-Controlled, Phase II Study

Objective

To determine the effect of selexipag, an oral, selective IP prostacyclin receptor agonist, on the frequency of attacks of Raynaud's phenomenon (RP) in patients with systemic sclerosis (SSc).

Methods

Patients with SSc‐related RP were randomized 1:1 to placebo (n = 38) or selexipag (n = 36) in individualized doses (maximum of 1,600 μg twice daily) during a 3‐week titration period. The primary end point was the weekly average number of RP attacks during the study maintenance period, analyzed using a Bayesian approach with a negative binomial model adjusted for baseline number of RP attacks. Other outcome measures included Raynaud's Condition Score (RCS), RP attack duration, and treatment‐emergent adverse events (AEs).

Results

Baseline characteristics were comparable between treatment groups. For 83.3% of patients, the individualized maintenance dosage of selexipag was ≤800 μg twice daily. No significant difference was observed between placebo and selexipag in weekly average number of electronic diary (eDiary)–recorded RP attacks during the maintenance period (14.2 attacks during the maintenance period and 21.5 attacks during the baseline week in the placebo group [n = 32] versus 18.0 attacks during the maintenance period and 22.4 attacks during the baseline week in the selexipag group [n = 27]; adjusted mean treatment difference of 3.4 in favor of placebo). No significant treatment effect was observed on RCS or RP attack duration. In the double‐blind period, 86.8% of placebo‐treated patients and 100% of selexipag‐treated patients reported ≥1 AE; 55.3% and 91.7%, respectively, reported ≥1 prostacyclin‐associated AE.

Conclusion

Treatment with selexipag did not reduce the number of RP attacks compared with placebo. The safety profile of selexipag was similar to that previously reported. This study provides important information about the feasibility of eDiary reporting of RP attacks in clinical trials.

Evidence-based management of Raynaud's phenomenon

Raynaud's phenomenon (RP) is relevant to the rheumatologist because it may signify an underlying connective tissue disease and also because it can be very challenging to treat, especially when it has progressed to digital ulceration or critical ischaemia. This review article discusses diagnosis (does this patient have an underlying connective tissue disease?), including the role for nailfold capillaroscopy, and treatment. Management of 'uncomplicated' RP is first described and then treatment of RP complicated by progression to digital ulceration or critical ischaemia, highlighting recent advances (including phosphodiesterase type 5 inhibition, and endothelin 1 receptor antagonism) and the evidence base underpinning these. Possible future therapies are briefly discussed.

From pruritus to CREST syndrome in a middle aged woman

CREST syndrome, a subtype of scleroderma and Primary Biliary Cholangitis, is an autoimmune disease where the immune system is causing a progressive slow damage to the bile ducts. We report the case of a 67-year-old female patient presenting symptoms indicative of CREST syndrome. During her hospitalization in the internal medicine clinic and after the appropriate imaging and laboratory investigation the diagnosis of CREST syndrome was confirmed, and she was also diagnosed with PBC. This case adds up to a list of literature sources and several case reports which indicate the association of PBC and CREST syndrome, including the accompanied clinical symptoms and musculoskeletal manifestations of the latter.

Therapeutic implications from the pathogenesis of Raynaud's phenomenon

INTRODUCTION

Raynaud's phenomenon (RP) can be either primary (idiopathic) or secondary to a number of different diseases/conditions, when vasopasm can be superimposed upon structural vascular abnormality or a hyperviscosity state and may then lead to severe ischaemia with tissue damage. Treatment must be tailored to the individual. Areas covered: This review discusses how increased understanding of the pathogenesis of RP has driven and is driving new approaches to therapy, and how we are now better able to predict which patients presenting with RP are likely to have an underlying disease requiring specific intervention. Medline searches (1946 to August 2016) were conducted for 'Raynaud's' in combination with relevant terms including different drugs. All papers identified were English language, with abstracts. Expert commentary: Randomised controlled trials of RP present particular challenges. The major aim must continue to be development of safe, effective treatments for patients across the spectrum of RP.

Raynaud's Phenomenon: A Brief Review of the Underlying Mechanisms

Raynaud’s phenomenon (RP) is characterized by exaggerated cold-induced vasoconstriction. This augmented vasoconstriction occurs by virtue of a reflex response to cooling via the sympathetic nervous system as well as by local activation of α_2C adrenoceptors (α_2C-AR). In a cold-initiated, mitochondrion-mediated mechanism involving reactive oxygen species and the Rho/ROCK pathway, cytoskeletal rearrangement in vascular smooth muscle cells orchestrates the translocation of α_2C-AR to the cell membrane, where this receptor readily interacts with its ligand. Different parameters are involved in this spatial and functional rescue of α_2C-AR. Of notable relevance is the female hormone, 17β-estradiol, or estrogen. This is consistent with the high prevalence of RP in premenopausal women compared to age-matched males. In addition to dissecting the role of these various players, the contribution of pollution as well as genetic background to the onset and prevalence of RP are also discussed. Different therapeutic approaches employed as treatment modalities for this disease are also highlighted and analyzed. The lack of an appropriate animal model for RP mandates that more efforts be undertaken in order to better understand and eventually treat this disease. Although several lines of treatment are utilized, it is important to note that precaution is often effective in reducing severity or frequency of RP attacks.

Evidence for the Use of Epoprostenol to Treat Raynaud's Phenomenon With or Without Digital Ulcers

OBJECTIVE

To review the evidence for using intravenous (IV) epoprostenol to treat Raynaud's phenomenon (RP).

DATA SOURCES

The databases MEDLINE (1946 to March 2016), PubMed, and International Pharmaceutical Abstracts were searched using the terms epoprostenol, Flolan, Raynaud's disease, and CREST syndrome. Further literature sources were identified by reviewing article citations.

STUDY SELECTION AND DATA EXTRACTION

All English-language, clinical trials and case series evaluating IV epoprostenol for the management or treatment of RP were included. Lower-quality evidence were incorporated due to limited information.

DATA SYNTHESIS

Seven small uncontrolled studies/case series, 1 small placebo controlled study, and 1 larger randomized trial were identified and included. There was no consistent measurement of efficacy utilized, but improvements in hand temperature, RP attack duration and frequency were commonly associated with IV epoprostenol treatment (5 trials). There were conflicting data regarding effect sustainability, with 5 trials showing long-term effects and 3 showing immediate effects. Fewer ischemic ulcers developed during treatment with IV epoprostenol in 1 trial compared to conventional treatment. Ulcer healing ocurred in 2 trials. Common adverse effects included hypotension, headache, flushing, gastrointestinal symptoms, and jaw pain.

CONCLUSIONS

Available evidence supports the use of IV epoprostenol for treatment of severe RP in patients refractory or intolerant to standard therapies. The dose, titration schedule, and duration of IV epoprostenol utilized in studies varied, but a conservative approach to initiation should be considered. Patients who do not respond to intermittent infusions and have severe digital ischemia may require more aggressive regimens.