Cerebral ischemia in young patients: it is associated with mitral valve prolapse and abnormal platelet activity in vivo?

Stroke and Noninfective Native Valvular Disease

PURPOSE OF REVIEW

Embolic stroke of undetermined source is a challenging clinical entity. While less common than atrial fibrillation and endocarditis, many noninfective heart valve lesions have been associated with stroke and may be considered as culprits for cerebral infarcts when other more common causes are excluded. This review discusses the epidemiology, pathophysiology, and management of noninfective valvular diseases that are commonly associated with stroke.

RECENT FINDINGS

Calcific debris from degenerating aortic and mitral valves may embolize to the cerebral vasculature causing small- or large-vessel ischemia. Thrombus which may be adherent to calcified valvular structures or left-sided cardiac tumors may also embolize resulting in stroke. Tumors themselves, most commonly myxomas and papillary fibroelastomas, may fragment and travel to the cerebral vasculature. Despite this broad differential, many types of valve diseases are highly comorbid with atrial fibrillation and vascular atheromatous disease. Thus, a high index of suspicion for more common causes of stroke is needed, especially given that treatment for valvular lesions typically involves cardiac surgery whereas secondary prevention of stroke due to occult atrial fibrillation is readily accomplished with anticoagulation.

Prevalence of mitral valve prolapse in younger patients with cerebral ischaemic attacks. A blinded controlled study

The association between cerebral ischaemic attacks (CIA) and mitral valve prolapse (MVP) was investigated in a blinded study of 30 consecutive patients with cerebrovascular disease and 30 control patients matched by age, sex, and immediately apparent neurological signs. All patients were below the age of 40 years. Phonocardiography, motion-mode and two-dimensional echocardiography were performed at rest and during various manoeuvres. MVP demonstrated by all three diagnostic modalities was classified as definite and prolapse in at least one but not in all three tests were designated as ambiguous. Regarding the frequency of definite MVP, no statistically significant difference was demonstrated between patients with CIA (3%) and controls (0%). Ambiguous MVP was rather common in patients with cerebrovascular disease (13%) but equally frequent in control patients (20%). It is concluded that MVP does not appear particularly common in Northern Europe in younger patients with cerebral ischaemic events.

Mitral valve prolapse

Mitral valve prolapse is a common valvular abnormality that is the most common cause of severe non-ischaemic mitral regurgitation in the USA. The overall prognosis of patients with mitral valve prolapse is excellent, but a small subset will develop serious complications, including infective endocarditis, sudden cardiac death, and severe mitral regurgitation. We present a comprehensive review of mitral valve prolapse, examining normal mitral anatomy, the clinical and echocardiographic features of mitral valve prolapse, and the pathophysiology and genetics of the disorder. We discuss the contemporary management of both asymptomatic and symptomatic prolapse, with particular attention to the timing and technique of surgical repair. We conclude that echocardiography is the method of choice for diagnosing mitral valve prolapse, that clinical and echocardiographic features can predict which patients with prolapse are at highest risk for complications, and that mitral valve repair is the treatment of choice for symptomatic prolapse.

Diminished global fibrinolytic capacity in patients with mitral valve prolapse is associated with transient ischemic attacks

Although mitral valve prolapse (MVP) has shown to be associated with thromboembolic complications, the cause of thromboembolic events in those patients is still unknown. The purpose of this study was to evaluate the fibrinolytic activity in MVP patients. The study included 35 consecutive patients (25 women, mean age 25+/-11 years) with echocardiographically documented MVP and 25 age- and sex-matched subjects as a control group. Four of MVP patients have a history of transient ischemic attack (TIA). Global fibrinolytic capacity (GFC), a new technique that examines the effectiveness of the entire fibrinolytic system, was measured. Global fibrinolytic capacity was found to be nonsignificantly increased in MVP patients (3.14+/-1.42 microg/mL) compared to those in control subjects (2.36+/-1.33 microg/mL) (p>0.05). However, in four of these MVP patients who had a history of transient ischemic attack, the GFC level was significantly lower than in patients who have no history of transient ischemic attack (1.67+/-0.6 microg/mL vs 3.27+/-1.46 (microg/mL, p=0.003). Furthermore, the GFC levels of these four patients were less than those of controls (p=0.04). These results showed that global fibrinolytic activity was similar in MVP patients without a history of TIA and control subjects. However, MVP patients with a history of TIA had significantly decreased global fibrinolytic activity compared to controls and as well as MVP patients without a history of TIA.

Lack of evidence of an association between mitral-valve prolapse and stroke in young patients

BACKGROUND

Previous studies have reported a high prevalence of mitral-valve prolapse among patients with embolic stroke (28 to 40 percent), especially among young patients (those < or =45 years old); this finding has practical implications for prophylaxis. However, diagnostic criteria for prolapse have changed and are now based on three-dimensional analysis of the shape of the valve; use of the current criteria reduces markedly the frequency of such a diagnosis and increases its specificity. Previously described complications must therefore be reconsidered.

METHODS

In a case-control study, we reviewed data on 213 consecutive patients 45 years old or younger with documented ischemic stroke or transient ischemic attack between 1985 and 1995; they underwent complete neurologic and echocardiographic evaluations. The prevalence of prolapse in these patients was compared with that in 263 control subjects without known heart disease, who were referred to our institution for assessment of ventricular function before receiving chemotherapy.

RESULTS

Mitral-valve prolapse was present in 4 of the 213 young patients with stroke (1.9 percent), as compared with 7 of the 263 controls (2.7 percent); prolapse was present in 2 of 71 patients (2.8 percent) with otherwise unexplained stroke. The crude odds ratio for mitral-valve prolapse among the patients who had strokes, as compared with those who did not have strokes, was 0.70 (95 percent confidence interval, 0.15 to 2.80; P=0.80); after adjustment for age and sex, the odds ratio was 0.59 (95 percent confidence interval, 0.12 to 2.50; P=0.62).

CONCLUSIONS

Mitral-valve prolapse is considerably less common than previously reported among young patients with stroke or transient ischemic attack, including unexplained stroke, and no more common than among controls. Using more specific and currently accepted echocardiographic criteria, therefore, we could not demonstrate an association between the presence of mitral-valve prolapse and acute ischemic neurologic events in young people.

Relation between mitral regurgitation and platelet activation

OBJECTIVES

This study sought to examine the effect of mitral regurgitation (MR) on platelet activation in patients with mitral valve prolapse (MVP) or rheumatic MR.

BACKGROUND

MVP and rheumatic MR are associated with an increased incidence of thromboembolic events. Although the underlying causes are not clear, increased platelet activation has been suggested as one of the pathogenic mechanisms. Results of previous studies that have investigated the relation between MVP and platelet activation are controversial. Whether the presence of MR in patients with mitral valve disease is associated with platelet activation remains unclear.

METHODS

We studied platelet activation by measuring the plasma level of platelet factor 4 (PF4) and beta-thromboglobulin (BTG) in 16 patients with MVP, 12 patients with rheumatic MR and 25 control subjects. A detailed echocardiographic examination, including M-mode measurement and color Doppler flow mapping to detect the presence and severity of MR was performed.

RESULTS

Patients and control subjects were matched for gender, age and left ventricular ejection fraction. Eight (50%) of 16 patients with MVP had MR. Patients with MVP and MR and patients with rheumatic MR had a significantly larger left atrial diameter. Mean log plasma levels of PF4 and BTG were significantly higher in patients with MVP and MR and patients with rheumatic MR than in control subjects (1.17 +/- 0.22 and 0.93 +/- 0.23 IU/ml vs. 0.52 +/- 0.34 IU/ml, p < 0.01; 1.70 +/- 0.21 and 1.53 +/- 0.15 IU/ml vs. 1.37 +/- 0.15 IU/ml, p < 0.05, respectively) but were comparable in patients with MVP and no MR and control subjects. Plasma levels of PF4 and BTG were positively correlated with the severity of MR, as assessed by a semiquantitative method (r = 0.59, p = 0.0001; r = 0.60, p = 0.0001, respectively). Increasing age and left atrial enlargement were not related to platelet activation.

CONCLUSIONS

MR in mitral valve disease was associated with systemic platelet activation. MVP itself was not associated with increased platelet activation. The degree of platelet activation was positively correlated with the severity of MR and was independent of the underlying etiology of mitral valve disease, age and left atrial size. The possibility of a higher incidence of thromboembolism and the role of antiplatelet agents in such patients will require further studies to determine.

A population-based study of stroke in the setting of mitral valve prolapse: risk factors and infarct subtype classification

OBJECTIVE

To determine the frequency of risk factors and the mechanisms of stroke in patients with cerebral infarction and echocardiographically diagnosed mitral valve prolapse in the general population.

DESIGN

We conducted a population-based study in Olmsted County, Minnesota, which encompassed the period from 1975 through 1989.

MATERIAL AND METHODS

Study subjects were identified by using the Rochester Epidemiology Project medical records-linkage system. Cardiac and neurologic data were summarized, and a two-sided chi 2 test or Fisher's exact test was used for statistical analysis.

RESULTS

Among residents of Olmsted County, Minnesota, 33 had echocardiographically diagnosed mitral valve prolapse and a first cerebral infarction between 1975 and 1989. The mean patient age was 71 years, and more than half (52%) were men. Risk factors for stroke included hypertension (55%), smoking (42%), coronary artery disease (27%), atrial fibrillation or flutter (24%), congestive heart failure (21%), hypertensive heart disease (21%), prior myocardial infarction (12%), diabetes (9%), and sick sinus syndrome (3%). Cerebral infarction subtypes were as follows: cardioembolic source (excluding mitral valve prolapse only), 30%; lacuna, 12%; large-vessel atherosclerosis, 9%; other, 6%; and infarction of uncertain cause (including mitral valve prolapse), 42%.

CONCLUSION

Most Olmsted County patients with cerebral infarction and echocardiographically diagnosed mitral valve prolapse had other risk factors for stroke, and most had identifiable mechanisms of infarction other than embolism due to mitral valve prolapse.

Cerebrovascular risk factors in migraine with prolonged aura and without aura

The role of cerebrovascular risk factors such as mitral valve prolapse, platelet aggregation, platelet activation and cardiac arrythmias in migraine was investigated in a total of 44 migraineurs (32 migraineurs without aura and 12 with prolonged aura) and 32 controls. Comparing the total of migraineurs and the two subgroups with controls, mitral valve prolapse, a raised thromboxane B2 level, at least one platelet aggregation dysfunction or an abnormality in 24-h ECG was statistically seen no more often than in the control group. Neither did combinations of the variables occur more frequently. Altogether, this study showed no increased coincidence of migraine with prolonged aura and migraine without aura with the above parameters. The absence of cardiac and haematological abnormalities in migraine with prolonged aura focuses attention on the control of the cortical microcirculation.

Acute homonymous field loss: really a diagnostic dilemma

A young woman developed the sudden onset of a congruous right lower quadratic visual field defect two weeks prior to examination. The remainder of her history and physical examination were noncontributory. Discussion revolves around the differential diagnosis of retro chiasmal field defects in young individuals. An MRI scan was most compatible with the diagnosis of disseminated sclerosis.

Etiology, prognosis, and hemostatic function after cerebral infarction in young adults

We retrospectively evaluated 66 patients younger than 40 years of age who presented with acute nonhemorrhagic cerebral infarction (n = 63) or transient ischemic attacks (n = 3) to determine the possible etiology and long-term outcome at a mean follow-up interval of 3 years after initial presentation. A probable cause for the stroke was identified in 24 patients (36%); this group included one woman with a history of recurrent spontaneous abortions and a positive test for the presence of the lupus anticoagulant. We performed detailed hemostatic investigations at follow-up in 38 (90%) of the remaining 42 patients in whom the cause of the stroke was unknown or uncertain; results of the basic hemostatic screening tests (including that for fibrinogen) were uniformly normal. All 38 patients demonstrated a normal fibrinolytic response as measured by tissue plasminogen activator release to a standard venous occlusion stress test; concentration of the inhibitor of tissue plasminogen activator was not increased. No abnormalities in the concentrations of the inhibitory proteins C or S or antithrombin III were identified, and none of the 38 patients had evidence of a lupus anticoagulant. Neurologic recovery was complete or the residual disability mild in 46 of 59 (78%) patients. Overall prognosis was excellent and independent of whether a precipitating factor for the stroke could be identified.

Platelet aggregation in transient global amnesia

We found a correlation between increased platelet aggregation parameters and transient global amnesia and no differences between patients with transient global amnesia and transient ischemic attacks. Our findings support the theory of a vascular mechanism for transient global amnesia.

Cerebral ischemia and mitral valve prolapse: case-control study of associated factors

We evaluated 36 patients with cerebral ischemia and mitral valve prolapse and compared them with 36 age-matched controls with cerebral ischemia who had similar attributes but who did not have mitral valve prolapse. Stepwise logistic regression analysis revealed an inverse relation between cerebral ischemia in the presence of mitral valve prolapse and hypertension, diabetes mellitus, occlusive cerebrovascular disease, and completed stroke at p less than 0.01. We also found, by correlation analysis, a negative correlation between both hypertension and diabetes mellitus versus mitral valve prolapse at p less than 0.05. Overall, 10 study patients compared with two control patients had no risk factors for cerebrovascular disease detected (chi 2 = 4.9, p less than 0.05). These data indicate that the association of mitral valve prolapse and cerebral ischemia is of special importance in patients who do not have other detected risk factors for cerebrovascular disease.

Mitral valve prolapse

Mitral valve prolapse is a common mitral valve disorder manifested clinically as a midsystolic click and/or a late systolic murmur (the click-murmur syndrome) and pathologically as billowing or prolapsing mitral leaflets (the floppy valve syndrome). Not only is it one of the two most common congenital heart diseases and the most common valve disorder diagnosed in the United States, but it is also prevalent throughout the world. Mitral valve prolapse may be associated with a variety of other conditions or diseases. Diagnosis of mitral valve prolapse should be made on clinical grounds and, if necessary, supported by echocardiography. The majority of patients with mitral valve prolapse suffer no serious sequelae. However, major complications such as disabling angina-like chest pains, progressive mitral regurgitation, infective endocarditis, thromboembolism, serious arrhythmias, and sudden death may occur. Unless these serious complications occur, most of the patients with mitral valve prolapse need no treatment other than reassurance, including those with atypical chest pain or palpitation unconfirmed by objective data. Therapy with a beta-blocker for disabling chest pain and/or arrhythmias and antiplatelet therapy for cerebral embolic events may be indicated. In occasional patients with significant mitral regurgitation surgery may be necessary.

Mendelian etiologies of stroke

There are many genetic disorders associated with an increased risk for stroke that may easily be overlooked in the evaluation of both adult and pediatric acute stroke victims. The recognition of a genetic disorder as the cause of a stroke has important implications not only for the immediate care of the stroke victim, but often also for others in the patient's family who may be at risk for the same disease and for whom preventive measures sometimes can be taken. We present here a comprehensive review of genetic disorders associated with stroke in the nongeriatric age groups for which a causative role in the evolution of stroke has been recognized or is likely. For each disorder, the major clinical and biochemical characteristics as well as the probable pathogenetic mechanisms of stroke are discussed, together with the appropriate testing required to screen for and confirm the diagnosis. The great variety of genetic disorders and mechanisms causing stroke underscores the increasing importance of understanding genetic disease for appropriate diagnosis and treatment of a common clinical problem affecting both children and adults.

Mitral valve prolapse and platelet aggregation in patients with hemiplegic and non-hemiplegic migraine

Migraine and mitral valve prolapse (MVP) share a number of features. Both migraine and MVP show platelet dysfunctions and an increased risk of transient ischemic attacks (TIA) and stroke. There is a strikingly high incidence of migraine among MVP patients. The focal neurological deficits associated with hemiplegic migraine resemble TIA symptoms which may occur in MVP patients. Furthermore, the risk of cerebral infarction in migraineurs is reported to be higher than in the general population. The results of our study with 43 patients suffering from non-hemiplegic migraine (common and classical migraine) and 19 migraineurs with a hemiplegic migraine indicate that hemiplegic migraine is not associated with MVP and increased platelet aggregation more frequently than other migraine forms. Independent of migraine type, there is no difference between patients with and without mitral valve prolapse with respect to platelet dysfunction.

Antithrombotic therapy in patients with valvular heart disease and prosthetic heart valves

Indications and the type of antithrombotic therapy for the prevention of thromboembolism in patients with valvular heart disease, mechanical prosthetic heart valves and bioprosthetic heart valves are discussed. The evidence for these clinical recommendations is described and graded into five levels. The indications for anticoagulation in patients with valvular heart disease are chronic or paroxysmal atrial fibrillation, sinus rhythm with a very large left atrium, severe left ventricular dysfunction or presence of heart failure or a history of previous thromboembolism. Anticoagulant therapy is administered to prolong the prothrombin time to 1.5 to 2.0 times control, using rabbit brain thromboplastin (standardized international normalized ratio = 3.0 to 4.5). Risk factors for thromboembolism in patients with prosthetic heart valves are discussed. Because intracardiac thrombus formation may start during and continues early after operation, restarting heparin therapy 6 hours after operation and continuing it for the duration of the hospitalization is advised. For mechanical prosthetic heart valves, oral anticoagulation as outlined plus dipyridamole is advised indefinitely. Platelet inhibitor therapy alone is insufficient. For bioprosthetic heart valves, heparin is followed by oral anticoagulation as outlined for 3 months after mitral or aortic valve replacement and indefinitely after mitral valve replacement if there is atrial fibrillation or a very large left atrium; aspirin may be recommended indefinitely after aortic valve replacement. Antithrombotic therapy is also considered for four special situations: noncardiac surgery, prosthetic valve endocarditis, anticoagulation after a thromboembolic event, and antithrombotic therapy during pregnancy.

No effect of acetylsalicylic acid on B-thromboglobulin and platelet factor 4 plasma levels in patients with transient ischaemic attacks

We studied the effect of acetylsalicylic acid (ASA) versus placebo on B-thromboglobulin (B-TG) and platelet factor 4 (PF4) plasma levels and ADP-induced platelet aggregation in 25 male patients with transient ischaemic attacks (TIA). The patients were allocated randomly to two groups: 14 patients received oral treatment with ASA 500 mg b.i.d. for 14 days, 11 patients placebo b.i.d. for the same period. B-TG and PF4 plasma levels and ADP-induced platelet aggregation were determined in basal conditions, and two hours, and seven and fourteen days after starting with ASA or placebo. In addition, the same parameters were studied in a group of 20 healthy males of matched age. Basal levels of plasma B-TG and PF4 and the maximal amplitude of ADP-induced platelet aggregation were abnormally high in TIA patients. ASA caused a significant reduction of B-TG plasma levels in TIA patients 2 hours after the first administration, but no effect was observed at the 7th and 14th day of treatment. PF4 plasma levels were unaffected by ASA treatment. It is concluded that ASA, at the dose conventionally used in clinical trials, does not affect the release of two alpha-granule proteins.

Platelet function and coagulation studies in patients with mitral valve prolapse

Twenty-eight consecutive patients with mitral valve prolapse (MVP), seven of whom had previous cerebrovascular disorders (CVD), were studied for platelet function and coagulation tests. While platelet function tests were found to be normal with the exception of platelet aggregation rate (PAR), there was a significant rise of factors VIII vWF:Ag (Von Willebrand) and (FPA) fibrinopeptide A. Six cases had high levels of both these factors, suggesting the existence of a particular subset of patients with MVP, with a higher risk of thromboembolic episodes, although only three out of seven patients with previous CVD had either FPA or VIII vWF:Ag levels. The broad spectrum of subjects with MVP probably explains the different results obtained when studying platelet function and coagulation factors. Therefore, larger population studies and prolonged follow-up of cases with either coagulation abnormalities similar to the ones found in the present report and/or altered platelet function tests are suggested to discover if it is possible to detect patients with a potential for thromboembolism.

Neurologic disorders associated with mitral valve prolapse

Mitral valve prolapse has been reported to be associated with a variety of neurologic disorders, including cerebral ischemia, transient global amnesia, migraine, autonomic dysfunction, and psychiatric disease. The evidence supporting these associations and possible pathogenetic mechanisms are discussed. Some neurologic disorders may be direct complications of mitral valve prolapse, while others may occur as part of an underlying genetic defect or common link.

Detection of mitral valve abnormalities by carotid Doppler flow study: implications for the management of patients with cerebrovascular disease

Patients with symptoms of cerebral ischemia are often evaluated with non-invasive carotid artery testing. An abnormal carotid Doppler ultrasound frequency shift pattern of early systolic flutter (ESF) was demonstrated by auscultation and velocity wave form analysis in patients with normal carotid bifurcations. Ten of these patients were studied with echocardiography (echo) and eight had mitral valve prolapse (MVP). To evaluate the association between ESF and MVP, a prospective blinded study was performed, recording carotid Doppler frequency shift in 50 patients referred for routine echocardiography. A total of 18 patients had ESF: 9/12 patients with MVP by echocardiography had ESF. Nine additional patients without MVP had ESF (two with mitral regurgitation and two with redundant mitral valves). The association of ESF with MVP was significant (p less than 0.001). The findings of ESF with a normal carotid artery by non-invasive testing suggests a possible mitral valve origin for symptoms of cerebrovascular disease.

Effects of low dose aspirin on platelet function in patients with recent cerebral ischemia

We tested the antiplatelet effects of low-dose aspirin in patients with occlusive cerebrovascular disease, because conventional dosage aspirin inhibits vascular synthesis of prostacyclin at the same time that it inhibits platelets. The effects on platelet function and thromboxane A2 synthesis of 40 mg of aspirin daily or 40 mg aspirin plus dipyridamole were measured in 23 patients starting within a week after the onset of cerebral ischemia. All patients had normal baseline platelet aggregation responses to four stimuli: arachidonate, epinephrine, adenosine diphosphate and collagen. The generation of thromboxane A2 by platelets, measured as serum thromboxane B2, was also normal. After 3 to 7 days of low dose aspirin therapy, platelet aggregation responses were suppressed to the extent observed with higher dosage aspirin. Serotonin release during platelet aggregation was inhibited by more than 95% and thromboxane B2 levels in clotted blood fell by more than 95%. Responses to aspirin treatment were similar in patients with transient ischemic attacks and in those with stroke and were also similar in both sexes. No differences in platelet responses were observed between patients receiving aspirin alone and aspirin plus dipyridamole. Thus 40 mg aspirin daily inhibited platelet responses as effectively as higher doses of aspirin in patients who had recent cerebral ischemia and showed a cumulative antiplatelet effect.

Increased excretion of immunoreactive thromboxane B2 in cerebral ischemia

Thromboxane B2 (TXB2) is the stable metabolite of thromboxane A2 (TXA2), a potent vasoconstrictor which induces irreversible platelet aggregation. The inhibition of TXA2 by aspirin and other agents has been associated with improved outcome following cerebral ischemia in clinical and laboratory studies. To investigate the relation of TXA2 production to cerebral ischemia, we measured the urinary excretion of TXA2 metabolites in 30 patients with acute cerebral ischemia. Urinary immunoreactive TXB2 for this group of ischemic patients was elevated compared to normals, 1818 +/- 344 pg/mg Cr (mean +/- SE) vs 880 +/- 122 pg/mg Cr (p less than .05). Among various subsets of the ischemic patients, those with severe stroke (2108 +/- 536 pg/mg Cr), large vessel disease (1646 +/- 335 pg/mg Cr), and cardiogenic stroke (2712 +/- 1045 pg/mg Cr) were all significantly elevated. Of the stroke patients, only the males demonstrated this significant elevation. These elevations of urinary immunoreactive TXB2 are consistent with a role for increased platelet activation in the pathogenesis of some forms of cerebral ischemia and suggest that gender differences in arachidonate metabolism may exist for stroke patients.

Study of platelet activation in migraine: control by low doses of aspirin

Although platelet activation is known to occur during migraine attacks, the cause-effect relationship remains to be determined. This problem was approached by studying the possible occurrence of platelet activation in vivo in headache-free periods of subjects affected by common or classic migraine and, subsequently, by verifying the possibility of its pharmacological control through administration of a classic anti-aggregation drug such as aspirin (ASA). The plasma levels of beta-thromboglobulin (beta-TG) and platelet factor 4 (PF4), indices of the occurrence of platelet activation in vivo, were therefore first assayed in both groups of migraine sufferers in the absence of therapy and then during the administration of aspirin (50 mg/daily). In the group of 15 patients affected by classic migraine, basal plasma levels of beta-TG and PF4 were significantly higher than control subjects. On the other hand, only beta-TG plasma levels were significantly higher in the group of 18 patients affected by common migraine. Patients suffering from classic migraine showed a high incidence of platelet activation (greater than 90%) in comparison with common migraine patients (approximately 33%). This suggests that platelet activation occurs in vivo in migrainous patients also during headache-free periods. Administration of aspirin to the patients affected by common and classic migraine caused a decrease in plasma beta-TG and PF4 concentration. Consequently, pharmacological treatment with aspirin in adequate dose may prove to be helpful in diminishing the vascular side-effects known to occur in migraine sufferers.