The effect of captopril on cutaneous blood flow in patients with primary Raynaud's phenomenon

Angiotensin II receptor blockers in dermatology: a narrative review

Angiotensin II receptor blockers (ARBs) are commonly used for cardiovascular diseases, especially for patients who can't tolerate the side effects of cough and angioedema caused by angiotensin converting enzyme inhibitors (ACEIs). However, the evidence of using ARBs in dermatology is mostly anecdotal and limited to case reports or small case series. Here we present a narrative review focusing on the therapeutic use of ARBs in dermatology and adverse cutaneous reactions due to the administration of ARBs.

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.

Renin—Angiotensin System Mediators and Raynaud's Phenomenon

Objective:

To review the use of angiotensin-converting enzyme (ACE) inhibitors and angiotensin II receptor blockers (ARBs) in the treatment of Raynaud's phenomenon (RP).

Data Sources:

Biomedical literature was accessed through July 2006 via PubMed, the Iowa Drug Information System (OS), and Cumulative Index to Nursing and Allied Health Literature (CINAHL) Plus. PubMed database terms included Raynaud's disease, angiotensin-converting enzyme inhibitors, and angiotensin II type 1 receptor blockers [pharmacological action]; IDIS terms included hypotensive agents-ace inhib 24080200, raynaud's syndrome 443.0, and hypotensive agents-angioten II 24080400; and CINAHL Plus terms included Raynaud's disease, angiotensin-converting enzyme inhibitors, losartan, and irbesartan.

Study Selection and Data Extraction:

All clinical trials published in English that reported both subjective and objective outcomes of efficacy were reviewed.

Data Synthesis:

Several small, short-term studies have evaluated captopril, enalapril, and losartan in the treatment of RP. The studies of ACE inhibitors have found conflicting results in their ability to improve digit blood flow and reduce both frequency and severity of RP attacks. Two studies have focused on the use of losartan for RP treatment, with both finding a statistically significant reduction in attacks and one showing improvement in symptoms of RP in comparison with the commonly utilized calcium-channel blocker, nifedipine. Most of the studies were short term (≤2 wk) and included a limited number of patients (CONCLUSIONS: ACE inhibitors and ARBs may provide some minor benefits in the relief of RP, although no definite evidence exists to suggest that they are superior to traditionally used treatments such as calcium-channel blockers. Larger, randomized controlled trials of longer duration are needed to compare the effectiveness of ACE inhibitors and ARBs with conventional treatment.

Oral vasodilators for primary Raynaud's phenomenon

BACKGROUND

Many different drugs have been suggested for the symptomatic treatment of primary Raynaud's phenomenon. Apart from calcium channel blockers, which are considered the drugs of choice, the 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 various drugs with vasodilator actions on primary Raynaud's phenomenon.

SEARCH METHODS

For this update the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched 14 May 2012), CENTRAL (Issue 4, 2012) and clinical trials databases. We contacted one pharmaceutical company and one trial author for additional information. In addition, the reference lists of relevant studies were searched for additional citations. There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials evaluating the effects of oral formulations of any drug with vasodilator effects on subjective symptoms in primary Raynaud's phenomenon. Treatment with, or comparison with, calcium channel blockers was not assessed in this review.

DATA COLLECTION AND ANALYSIS

Two members of the review team independently assessed the trials for inclusion and their quality and extracted the data. Data extraction included adverse events. We contacted trial authors for missing data.

MAIN RESULTS

Eight studies involving 290 participants were included. Two trials examined the effects of captopril, the rest were single trials on single drugs. All comparisons were with placebo. The methodological quality of most trials was poor.Enalapril was associated with a small increase in the frequency of attacks per week (difference in means 0.8; 95% CI 0.43 to 1.17). The difference between the intervention groups on a subjective improvement score was non-significant. There was a significant effect of buflomedil on the frequency of attacks per week (weighted mean difference (WMD) -8.8; 95% CI -17.55 to -0.09), but there was no evidence of effect on the severity score. The proportion with fewer attacks was significantly higher on moxisylyte than on placebo (relative risk (RR) 4.33; 95% CI 1.36 to 13.81). For captopril, beraprost, dazoxiben and ketanserin there was no evidence of an effect on the frequency, severity or duration of attacks. Beraprost and moxisylyte gave significantly more adverse effects than placebo.

AUTHORS' CONCLUSIONS

Poor methodological quality, small sample sizes and the limited data available resulted in low precision of the statistical results and limited value of the overall results .The overall results show that there is no evidence for an effect of vasodilator drugs on primary Raynaud's phenomenon.

Oral vasodilators for primary Raynaud's phenomenon

BACKGROUND

Many different drugs have been suggested for the symptomatic treatment of primary Raynaud's phenomenon. Apart from calcium channel blockers, which are considered the drugs of choice, the evidence of the effects of alternative pharmacological treatments is limited.

OBJECTIVES

To assess the effects of various drugs with vasodilator actions on primary Raynaud's phenomenon.

SEARCH STRATEGY

The Cochrane Peripheral Vascular Diseases Group searched their Specialised Register (last searched 24 July 2007), and the Cochrane Central Register of Controlled Trials (CENTRAL) (last searched Issue 3, 2007). In addition, we searched MEDLINE (January 1966 to July 2007), EMBASE (1980 to July 2007) and reference lists of relevant articles. We contacted pharmaceutical companies. There were no language restrictions.

SELECTION CRITERIA

Randomised controlled trials evaluating the effects of oral formulations of any drug with vasodilator effects on subjective symptoms in primary Raynaud's phenomenon. Treatment with, or comparison with, calcium channel blockers was not assessed in this review.

DATA COLLECTION AND ANALYSIS

Both authors assessed the trials for inclusion and their quality. One author (BV) extracted the data MS checked the results. Data extraction included adverse events. we contacted trial authors for missing data.

MAIN RESULTS

Eight studies involving 290 participants were included. Two trials examined the effects of captopril, the rest were single trials on single drugs. All comparisons were with placebo. The methodological quality of most trials was poor. Enalapril was associated with a small increase in the frequency of attacks per week (difference in means 0.8; 95% CI 0.43 to 1.17). The difference between the intervention groups on a subjective improvement score was non-significant. There was a significant effect of buflomedil on the frequency of attacks per week (weighted mean difference (WMD) -8.8; 95% CI -17.55 to -0.09), but there was no evidence of effect on the severity score. The proportion with fewer attacks was significantly higher on moxisylyte than on placebo (relative risk (RR) 4.33; 95% CI 1.36 to 13.81). For captopril, beraprost, dazoxiben and ketanserin there was no evidence of an effect on the frequency, severity or duration of attacks. Beraprost and moxisylyte gave significantly more adverse effects than placebo.

AUTHORS' CONCLUSIONS

Poor methodological quality, small sample sizes and the limited data available resulted in low precision of the statistical results and limited value of the overall results . The overall results show that there is no evidence for an effect of vasodilator drugs on primary Raynaud's phenomenon.

Prevention of vascular damage in scleroderma and autoimmune Raynaud's phenomenon: a multicenter, randomized, double-blind, placebo-controlled trial of the angiotensin-converting enzyme inhibitor quinapril

OBJECTIVE

To evaluate the efficacy and tolerability of prolonged administration of quinapril, a long-acting angiotensin-converting enzyme inhibitor, in the management of the peripheral vascular manifestations of limited cutaneous systemic sclerosis (lcSSc) and in the prevention of the progression of visceral organ involvement in the disease.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled study evaluating quinapril 80 mg/day, or the maximum tolerated dosage, in 210 patients with lcSSc or with Raynaud's phenomenon (RP) and the presence of SSc-specific antinuclear antibodies. Treatment was for 2-3 years. The primary outcome measure was the number of new ischemic ulcers appearing on the hands; secondary measures were the frequency and severity of RP attacks, skin score, treatments for ischemia, health status (measured by the Short Form 36 instrument), measures of kidney and lung function, and echocardiographic estimates of pulmonary artery pressure. An intent-to-treat analysis was used.

RESULTS

Quinapril did not affect the occurrence of digital ulcers or the frequency or severity of RP episodes. It did not alter the treatments that were prescribed for either infected ulcers or severe RP symptoms. There was no apparent effect on the estimated tricuspid gradient. Health status was not affected by quinapril, and one-half of the patients who believed they had benefited from the trial treatment were in the placebo arm. Quinapril was not tolerated by one-fifth of the patients, with dry cough being the most frequent side effect.

CONCLUSION

Administration of quinapril for up to 3 years had no demonstrable effects on the occurrence of upper limb digital ulcers or on other vascular manifestations of lcSSc in this patient population.

The diagnosis and treatment of Raynaud's phenomenon: a practical approach

Raynaud's phenomenon is a common disorder with vasospasm of the digital arteries causing pallor with cyanosis and/or rubor. It can be primary (idiopathic), where it is not associated with other diseases, or secondary to several diseases or conditions, including connective tissue diseases, such as scleroderma and systemic lupus erythematosus. Raynaud's is often mild enough to not require treatment; however, with secondary Raynaud's there is not only vasospasm but also fixed blood vessel defects so the ischaemia can be more severe. Complications can include digital ulcers and could, rarely, lead to amputation. Treatment is often non-pharmacological including avoiding cold and smoking cessation. Calcium channel antagonists, such as nifedipine, are often considered when treatment is needed; however, adverse effects of these drugs can include hypotension, vasodilatation, peripheral oedema and headaches. Other treatments have been studied in randomised, controlled trials including classes of drugs, such as angiotensin II inhibitors, selective serotonin reuptake inhibitors, phosphodiesterase-5 inhibitors (e.g. sildenafil), nitrates (topical or oral; the latter can be limited by adverse effects, such as flushing, headache and hypotension), and for more serious Raynaud's or its complications prostacyclin agonists may be used. There are two large studies that demonstrate that endothelin receptor blockade with bosentan can reduce the number of new digital ulcers in scleroderma patients. However, it does not affect the healing period. Thus, Raynaud's is common and often requires non-pharmacological treatment. When secondary Raynaud's is suspected, such as Raynaud's with an older age at onset or other features of connective tissue disease, then an appropriate history, physical examination and laboratory tests may be indicated to reach an appropriate diagnosis. There have been advances in pharmacological treatment, but some of the treatments are limited by adverse effects.

[Evidence-based therapy of Raynaud's syndrome]

Raynaud's syndrome has a prevalence of 3-5% in the general population. Despite its high frequency, the majority of available therapies have not been validated in randomized controlled trials. Effective therapies with a high level of evidence include the calcium channel blocker nifedipine. As analyzed by meta-analyses, nifedipine showed improvement of the peripheral circulation, as well as reduction of both the intensity and frequency of attacks in patients with primary and secondary Raynaud's syndrome as compared to placebo. Similar results in a metaanalysis were obtained for intravenous infusions of iloprost in patients with secondary Raynaud's phenomenon associated with systemic sclerosis. In addition, intravenous infusions of iloprost improved healing of fingertip ulcers in patients with systemic sclerosis. Therapies with significant effects in single randomized controlled trials include angiotensin II-receptor type 1 antagonists (losartan), the calcium channel blockers felodipine und amlodipine, serotonin-reuptake-inhibitors (fluoxetine) und phosphodiesterase-V-inhibitors (sildenafil, vardenafil). However, the results for these promising substances have to be confirmed in long-term trials with larger patient numbers.

[Raynaud phenomenon in dermatology : Part 2: therapy]

While primary Raynaud phenomenon (RP) only rarely leads to complications, secondary RP when associated with systemic sclerosis (SSc) frequently results in necrosis, ulcers or even gangrene. Therefore timely therapeutic intervention is required. Management of RP includes physical therapy, avoidance of triggers, and a variety of medications, depending on the disease severity. On the basis of published studies and of our own experience we suggest: a) for primary and uncomplicated secondary RP, calcium channel blockers in adequate doses; b) for SSc-associated secondary RP with hypertension, cardial or renal involvement, drugs which interfere with angiotensin; c) in case of concomitant depression, exploitation of the vasodilatory effects of serotonin reuptake inhibitors, d) in presence of ulcers or marked trophic alterations, intravenous administration of iloprost, e) for recalcitrant cases and endangered digits, sildenafil, f) for prevention of severe relapses, the endothelin-receptor antagonist bosentan. The drugs mentioned in c-f are not approved for RP and used off-label. In patients with secondary SSc-associated RP, timely therapy can reduce the percentage of complications such as ulcers or amputations. In addition, timely treatment of RP possibly retards ensuing fibrotic processes.

Is there a vasospasmolytic effect of acupuncture in patients with secondary Raynaud phenomenon? Gibt es einen vasospasmolytischen Effekt der Akupunktur bei Patienten mit sekundarem Raynaud-Phanomen?

BACKGROUND

Raynaud phenomenon (RP) is a vasospastic disorder of the digital arteries. Severe forms are found in patients with connective tissue diseases. Vasospasmolytic therapies are often limited by side effects such as orthostatic hypotension.

PATIENTS/METHODS

We investigated therefore the effect of acupuncture in a double blind, placebo-controlled, randomized trial in patients with secondary RP. The study was performed during the winter season by licensed acupuncturists weekly for 8 weeks (points chosen for the verum group: L.I.4, S.J.5, St.36, P.6, Du.20, Ex.28).

RESULTS

An improvement was detected in both groups but there was no significant effect on clinical symptoms - based on patient diaries (average number of attacks before and after treatment: verum 1.9 +/- 2.0 vs. 1.4 +/- 1.7 attacks/ day and placebo 2.8 +/- 1.8 vs. 1.9 +/- 1.1; duration of attacks: verum 15 +/- 12 vs. 12 +/- 9 min. and placebo 31 +/- 17 vs. 16 +/- 6; n.s.) or on skin microcirculation, measured by local cold testing.

CONCLUSIONS

A specific vasospasmolytic effect of acupuncture could not be proven. This may be due to minor morphologic changes of supplying arteries or a severe local defect in endothelial function rather than a neurological disturbance which might be influenced by acupuncture. Much larger studies would be needed to identify the possible small benefit from acupuncture. If long-term relief is not obtained, it is unlikely to be cost-effective.

Cutaneous laser Doppler flowmetry: applications and findings

OBJECTIVE

To examine the historical development, evolution, strengths and weaknesses, and applications (current and future) of laser Doppler flowmetry (LDF).

DESIGN

A review and summary of the literature on the cutaneous uses and successful applications of LDF are presented as well as a brief discussion of the noncutaneous and nonvascular applications.

MATERIAL AND METHODS

LDF measures Doppler-shifted quantities of reflected laser light at a superficial level to determine cutaneous and noncutaneous microcirculatory flux of erythrocytes. LDF is non-invasive and inexpensive.

RESULTS

This relatively recent technologic development has shown considerable potential as a tool for evaluating the cutaneous circulation. Although early studies suggested that LDF had substantial difficulties with sampling, stability, and reproducibility, subsequent refinements in equipment and application have led to technical acceptability.

CONCLUSION

LDF seems to be particularly valuable for assessing the microcirculation and real-time changes in skin blood flow. It has been used successfully in many investigations of the cutaneous and noncutaneous blood flow in patients with fixed or vasospastic vascular disorders, neuropathies, tumors, or ulcers as well as those who have undergone intestinal, orthopedic, or plastic surgical procedures.

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.

A comparison of the effects of captopril and enalapril on skin responses to intradermal bradykinin and skin blood flow in the human forearm

1. The effects of captopril and enalapril on skin responses to intradermal injections of bradykinin and skin blood flow in the forearm were investigated in this randomised, double-blind, placebo-controlled, cross-over study. 2. Intradermal injections of 0, 1, 2.5 and 5 micrograms of bradykinin in 0.9% sodium chloride were made into the forearm of twelve healthy volunteers before and at 2, 6 and 24 h after single oral doses of 25 mg captopril, 10 mg enalapril or placebo. Forearm skin blood flow was measured by the technique of laser Doppler flowmetry (LDF) before the injections were made and the skin responses evaluated at 15 min after injections of bradykinin by measurement of cutaneous blood flow outside the induced weal, erythema area and weal volume. 3. The bradykinin-induced cutaneous responses measured by LDF, erythema area and weal volume increased with incremental bradykinin dose. Compared with placebo, captopril significantly augmented the cutaneous vasodilator effects of bradykinin, measured by LDF and erythema area, at 2 h and the weal responses at 2 and 6 h. Enalapril enhanced the vasodilator responses to bradykinin at 2 and 6 h and the weal responses at 2, 6 and 24 h. Neither captopril nor enalapril significantly affected forearm skin blood flow. 4. This study showed that captopril and enalapril potentiated the effects of intradermal bradykinin both with respect to blood flow changes and weal formation in keeping with effective kininase II inhibition and the time course of these changes are consistent with enalapril being a longer acting drug than captopril. Captopril and enalapril exerted no influence on forearm skin blood flow measured by LDF.

Raynaud's phenomenon. An update

The pathogenesis of primary Raynaud's phenomenon remains an enigma. Most evidence favors a local abnormality in the digital arteries as opposed to an increased activity of the sympathetic nervous system. The local fault may involve the alpha 2-adrenergic receptors, which are most important in reflex sympathetic vasoconstriction. Cooling blood vessels increase the sensitivity of alpha 2-adrenergic receptors, increased levels of alpha 2-adrenergic receptors are present in primary Raynaud's disease, and patients show an increased sensitivity to alpha 2-adrenergic receptor agonists on finger blood flow. Serotonin has also been implicated, but the evidence is not compelling. In secondary Raynaud's phenomenon, vasospastic attacks can often be explained by a low arterial distending pressure, a thickened vessel wall, or absence of beta-adrenergic receptor activity. Diagnosis of primary Raynaud's disease relies on a typical history and normal physical examination, laboratory studies, and nailfold capillaroscopy. Finger systolic blood pressures during local cooling with ischemia may be helpful to document vasospastic attacks but does not distinguish primary from secondary Raynaud's phenomenon. The treatment of Raynaud's phenomenon is usually conservative. Pavlovian conditioning or biofeedback may be beneficial. When drug therapy is necessary, the calcium channel entry blocker nifedipine or sympatholytic agents have been shown to decrease the frequency and duration of vasospastic attacks in about two thirds of patients, although subjective improvement does not usually correlate with objective testing. Direct-acting vasodilators have not been shown to be of definite benefit. New therapies include prostaglandins, captopril, and the serotonergic antagonist ketanserin. Surgical sympathectomy has not been beneficial.

Subjective and objective assessment of enalapril in primary Raynaud's phenomenon

1. The efficacy and acceptability of enalapril were assessed in a double-blind, randomised, placebo controlled cross-over study in 21 patients with primary Raynaud's phenomenon. 2. Skin temperature was assessed by thermocouples in response to a 15 degrees C cold water challenge as an index of digital blood flow. 3. Following enalapril there were no significant changes in the number and severity of Raynaud's attacks, and no subjective benefit from treatment as measured by visual analogue scales, 5 point rating scales, and skin temperature response to cold challenge when compared with placebo. 4. Enalapril in a dose of 20 mg daily is ineffective in the management of primary Raynaud's phenomenon.

Raynaud's phenomenon and disease

Maurice Raynaud initiated the discussion of cold-induced vasospasm over 125 years ago. Research has shown that the physiology of Raynaud's involves a complex interaction in both local and systemic factors. Although a multitude of laboratory tests are available to help evaluate the prognosis of Raynaud's phenomenon, patient history remains the most reliable method of diagnosis. There are a variety of treatment modalities available. The treatment program should be tailored to the severity and etiology of the disease.