Protease Inhibitors in Spontaneous Cervical Artery Dissections

Alpha1-antitrypsin deficiency and cardiovascular disease: questions and issues of a debated relation

Alpha1-antitrypsin (AAT) is one of the major inhibitors involved in protease/antiprotease homeostasis, and it is mainly produced by hepatocytes and pulmonary epithelial cells. Its deficiency, called alpha1-antitrypsin deficit (AATD), leads to severe hepatic and respiratory issues. Also, AAT is released into the bloodstream providing systemic anti-inflammatory effects. Apart from acting as an acute-phase anti-inflammatory protein, it can be a biomarker for monitoring disease evolution. A reduced or defective production leads to a loss of anti-inflammatory function, protease-antiprotease imbalance and cellular engorgement due to polymers deposition, with system-wide repercussions. This review aims to evaluate AATD condition in the major vessels of the head and neck, thoracic and abdominal districts. Also, a dedicated focus on autoimmune vascular diseases will be provided. A critical revision of the main literature findings starting from the 1980s until now has been performed. Studies conducted over the years have provided several contradictory pieces of evidence. Most authors acknowledge the protective and anti-inflammatory AAT role on the vascular endothelium. However, correlations between AATD and major arteries, cerebral and cardiovascular conditions, and autoimmune diseases remain unclear. Most studies recognize the role of AATD in vascular diseases but only as a cofactor inducing cellular and tissue structure impairments. However, this condition alone is not enough to determine new disease onset. Due to the opposing results reported over the years, there is still a considerable lack of knowledge on the role covered by AATD in vascular diseases. A renewed interest in this research field should be encouraged to grant new solid evidence and validate the putative role of AATD screening and replacement therapy as useful diagnostic and treatment tools.

Male Sex Is Associated With Cervical Artery Dissection in Patients With Fibromuscular Dysplasia

Background Cervical artery dissection (CeAD) is a frequent manifestation of fibromuscular dysplasia (FMD). However, risk factors for CeAD are unknown. We investigated factors associated with CeAD in the ARCADIA (Assessment of Renal and Cervical Artery Dysplasia) registry. Methods and Results The ARCADIA registry includes women or men aged ≥18 years, with a diagnosis of renal, cervical, or intracranial artery FMD, who were prospectively recruited at 16 university hospitals in France and Belgium. Diagnosis of acute or past CeAD at inclusion was established on imaging according to standard diagnostic criteria. Associations between potential determinants and CeAD were assessed by logistic regression analyses. Among 469 patients (75 men) with FMD, 65 (13.9%) had CeAD. Patients with CeAD were younger, more likely to be men, have a history of migraine, and less likely to have a history of hypertension than patients without CeAD. In the multivariable analysis, male sex (odds ratio [OR], 2.66; 95% CI, 1.34-5.25), history of migraine (OR, 1.90; 95% CI, 1.06-3.39), age ≥50 years (OR, 0.41; 95% CI, 0.23-0.73), history of hypertension (OR, 0.35; 95% CI, 0.20-0.64), and involvement of ≥3 vascular beds (OR, 2.49; 95% CI, 1.15-5.40) were significantly associated with CeAD. To validate the association between CeAD and sex, we performed a systematic review. We collected additional data on sex from 2 published studies and unpublished data from the US Registry for Fibromuscular Dysplasia and the European/International FMD Registry. In the pooled analysis (289 CeAD, 1933 patients), male sex was significantly associated with CeAD (OR, 2.04; 95% CI, 1.41-2.95; I²=0%). Conclusions In patients with FMD, male sex and multisite involvement are associated with CeAD, in addition to other previously known risk factors. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT02884141.

The potential dangers of neck manipulation & risk for dissection and devastating stroke: An illustrative case & review of the literature

Chiropractic cervical manipulation is a common practice utilized around the world. Most patients are never cleared medically for manipulation, which can be devastating for those few who are at increased risk for dissections. The high velocity thrust used in cervical manipulation can produce significant strain on carotid and vertebral vessels. Once a dissection has occurred, the risk of thrombus formation, ischemic stroke, paralysis, and even death is drastically increased. In this case report, we highlight a case of a 32-year-old woman who underwent chiropractic manipulation and had vertebral artery dissection with subsequent brainstem infarct. She quickly deteriorated and passed away shortly after arrival to the hospital. Although rare, one in 48 chiropractors have experienced such an event. We utilize this case to highlight the risk associated with cervical manipulation and urge open dialogue between chiropractors and physicians. Receiving medical clearance prior to cervical manipulation in potential at risk patients would drastically reduce morbidity and mortality.

A wide-necked extracranial internal carotid artery saccular aneurysm with ipsilateral proximal compression

Extracranial internal carotid artery aneurysms (EICAA) are rare and can elicit various neurologic symptoms. Here, we present a case of a saccular EICAA compressing its proximal parent internal carotid artery (ICA). Ultrasonography demonstrated the proximal ICA stenosis and the "tardus-parvus" Doppler waveform downstream. The patient underwent aneurysmectomy and graft interposition. The histologic analysis highly supported an atypical fibromuscular dysplasia. Although this patient only showed a neck mass, the reduced ipsilateral cerebral blood supply was a potential cause for neurologic symptoms. © 2016 Wiley Periodicals, Inc. J Clin Ultrasound 45:116-120, 2017.

The etiology of cervical artery dissection

The etiology of cervical artery dissection (CAD) is unclear, although a number of risk factors have been reported to be associated with the condition. On rare occasions, patients experience CAD after cervical spine manipulation, making knowledge about the cervical arteries, the predisposing factors, and the pathogenesis of the condition of interest to chiropractors. This commentary reports on the relevant anatomy of the cervical arteries, developmental features of CAD, epidemiology of the condition, and mechanisms of dissection. The analysis of CAD risk factors is confusing, however, because many people are exposed to mechanical events and known pathophysiological associations without ever experiencing dissection. No cause-and-effect relationship has been established between cervical spine manipulation and CAD, but it seems that cervical manipulation may be capable of triggering dissection in a susceptible patient or contributing to the evolution of an already existing CAD. Despite the many risk factors that have been proposed as possible causes of CAD, it is still unknown which of them actually predispose patients to CAD after cervical spine manipulation.

Cervical artery dissection: emerging risk factors

Cervical artery dissection (CAD) represents an increasingly recognized cause of stroke and the most common cause of ischemic stroke in young adults. Many factors have been identified in association with CAD such as primary disease of arterial wall (fibrodysplasia) and other non-specific diseases related to CAD like Ehlers Danlos-syndrome IV, Marfan's syndrome, vessel tortuosity. Moreover, an underlying arteriopathy which could be in part genetically determined, has been suspected. The rule of emerging risk factors for CAD such as recent respiratory tract infection, migraine and hyperhomocysteinemia are still a matter of research. Other known risks factors for CAD are major head/neck trauma like chiropractic maneuver, coughing or hyperextension injury associated to car. We examined emerging risks factors for CAD detected in the last years, as CAD pathogenesis is still not completely understood and needs further investigations.

Cervical-artery dissections: predisposing factors, diagnosis, and outcome

Cervical-artery dissection (CAD) is a major cause of cerebral ischaemia in young adults and can lead to various clinical symptoms, some of which are benign (eg, headache, neck pain, Horner's syndrome, and cranial-nerve palsy), but most patients have a stroke or transient ischaemic attack. In addition to trauma to the neck, other risk factors have been suggested, such as infection, migraine, hyperhomocysteinaemia, and the 677TT genotype of the 5,10-methylenetetrahydrofolate reductase gene (MTHFR 677TT), although evidence is sparse. An underlying arteriopathy, which could in part be genetically determined, is believed to have a role in the development of CAD. Importantly, both research on and optimum management of CAD strongly rely on diagnostic accuracy. Although the functional outcome of CAD is good in most patients, socioprofessional effects can be important. Incidence of the disorder in the general population is underestimated. Mortality and short-term recurrence rates are low but possibly also underestimated. Further research is warranted to improve our understanding of the underlying pathophysiology, to assess the long-term outcome, and ultimately to provide treatment and prevention strategies.

CADISP-Genetics: An International Project Searching for Genetic Risk Factors of Cervical Artery Dissections

Background

Cervical artery dissection (CAD) is a frequent cause of ischemic stroke, and occasionally death, in young adults. Several lines of evidence suggest a genetic predisposition to CAD. However, previous genetic studies have been inconclusive mainly due to insufficient numbers of patients. Our hypothesis is that CAD is a multifactorial disease caused by yet largely unidentified genetic variants and environmental factors, which may interact. Our aim is to identify genetic variants associated with an increased risk of CAD and possibly gene-environment interactions.

Methods

We organized a multinational European network, Cervical Artery Dissection and Ischemic Stroke Patients (CADISP), which aims at increasing our knowledge of the pathophysiological mechanisms of this disease in a large group of patients. Within this network, we are aiming to perform a de novo genetic association analysis using both a genome-wide and a candidate gene approach. For this purpose, DNA from approximately 1100 patients with CAD, and 2000 healthy controls is being collected. In addition, detailed clinical, laboratory, diagnostic, therapeutic, and outcome data are being collected from all participants applying predefined criteria and definitions in a standardized way. We are expecting to reach the above numbers of subjects by early 2009. Conclusions We present the strategy of a collaborative project searching for the genetic risk factors of CAD. The CADISP network will provide detailed and novel data on environmental risk factors and genetic susceptibility to CAD.

The genetics of cervical artery dissection: a systematic review

BACKGROUND AND PURPOSE

The pathophysiology of cervical artery dissections (CAD), a major cause of ischemic stroke in young adults, is poorly understood. Several arguments suggest a genetic predisposition.

METHODS

We systematically reviewed all published data on genetic risk factors for CAD and performed a meta-analysis of association studies with the MTHFR C677T polymorphism.

RESULTS

Rarely, CAD is associated with a known monogenic connective tissue disease, mainly vascular Ehlers-Danlos syndrome. However, in the large majority of CAD cases, there is no evidence for a known monogenic disease. Several arguments, including the association of CAD with dermal connective tissue abnormalities that are inherited, suggest that genetic factors also play a role in "sporadic" CAD as part of a multifactorial predisposition. We identified 15 genetic association studies: 10 were negative and 5 reported associations of 3 genetic variants in 3 different candidate genes. Two studies reported associations with polymorphisms in ICAM-1 and COL3A1, but neither has been replicated. Three studies reported an association with the MTHFR 677TT genotype, but 3 other studies did not replicate this. A meta-analysis of these data identified an overall significant association of the MTHFR 677TT genotype with CAD (OR, 1.67; 95% CI, 1.21 to 2.31). We also identified 9 studies screening candidate genes for mutations and 4 linkage studies, yielding mostly negative results.

CONCLUSIONS

Although several interesting hypotheses were generated, the majority of genetic studies in CAD have been negative until now, but they were markedly underpowered. Progress in unraveling the genetics of CAD will require the collection of DNA samples from large multicenter series.

Cervical artery dissection: pathology, epidemiology and management

BACKGROUND

Cervical artery dissection is often treated with anticoagulants to prevent ischemic stroke. The risk-benefit ratio of anticoagulation versus antiplatelet therapy is unclear.

OBJECTIVES

To provide an educational review of current data on the disease to explain the rationale for the treatment options and to explore the results of management studies in order to determine if anticoagulation is justified.

METHODS

We searched the databases MEDLINE and EMBASE as well as bibliographies for information on anticoagulants and antiplatelet agents in cervical, i.e. carotid and/or vertebral artery, dissection.

RESULTS

There are no randomized controlled trials on the treatment. One systematic review from 2003 identified 20 case series or cohort studies. We identified 9 additional studies with a total of 1,033 patients. Of those, 731 received anticoagulation sometimes followed by platelet inhibition vs. 282 patients treated with antiplatelet agents alone. The rate of ischemic stroke was 2.3% vs. 6.9% and bleeding complications were reported in 0.7% vs. 0%.

CONCLUSION

It cannot be excluded that there is a net benefit from anticoagulant therapy in cervical dissection, but the studies are flawed by considerable bias. Very ill patients at a high risk of ischemic stroke may have been given aspirin due to fear of hemorrhagic complications. A randomized controlled trial is planned and will be crucial to resolve this issue.

α1-antitrypsin gene polymorphisms are not associated with renal arterial fibromuscular dysplasia

OBJECTIVE

We previously showed that fibromuscular dysplasia (FMD) of the renal artery may be familial. Case reports have associated alpha1-antitrypsin deficiency and FMD. The aim of this study was to test the implication of the alpha1-antitrypsin (AAT) gene in a large cohort of patients with renal FMD.

MATERIALS AND METHODS

A case-control study comparing the genotype frequencies in 161 consecutive patients with angiographically proven renal FMD with those observed in three sets of controls (353 hypertensive patients, 288 normotensive patients, 444 normotensive women) was conducted. High-resolution echotracking of the carotid and radial arteries was performed in a subset of 77 FMD patients. Three functional polymorphisms of the AAT gene (PiM1, PiZ, PiS) were investigated.

RESULTS

Clinical (age 44.3 +/- 13.8 years, 85.1% women) and radiological (77.1% of multifocal lesions) characteristics of the FMD population were consistent with those previously published. No differences were found in AAT genotype frequencies in the FMD subjects compared with the 1085 controls. We found no correlation between the AAT genotypes and the clinical and angiographical characteristics of the FMD patients. Echotracking results confirmed our previously published results in FMD patients with a specific pattern and a mean arterial phenotypic score greater than 3. However, no difference in the arterial score was observed across the genotypes.

CONCLUSION

Polymorphisms PiM1, PiZ and PiS of the AAT gene are not associated with renal FMD or infraclinical carotid lesions detected by echotracking methods. As the true prevalence of renal FMD is not precisely known and alpha1-antitrypsin deficiency is not infrequent in the general population, the association of the two may occur by chance.

Non-Atherosclerotic Vascular Disease in the Young

There are a large variety of non-atherosclerotic causes of ischemic stroke in the young. Arterial dissection, most commonly associated with non-traumatic causes, is among the most common. Both the carotid and vertebrobasilar circulations can be affected. The vasculitidies represent a rare, but potentially treatable series of conditions that can lead to stroke through diverse mechanisms. Moyamoya is a nonatherosclerotic, noninflammatory, nonamyloid vasculopathy characterized by chronic progressive stenosis or occlusion of the distal internal carotid arteries and/or proximal portions of the middle and/or anterior cerebral arteries. Moyamoya can be idiopathic (moyamoya disease) or the result of other conditions. An appreciation of the unusual causes of stroke in the young is important when considering secondary prevention measures.

Diagnostic flow chart for targeted detection of alpha1-antitrypsin deficiency

BACKGROUND

Alpha1-antitrypsin (AAT) deficiency is under-recognized, probably because many individuals affected show no clinical impairment. The targeted detection is a tool to increase its recognition.

METHODS

We prospectively submitted to AAT serum levels determination, phenotyping and, if doubtful, genotyping: (i) patients with the early onset of emphysema, emphysema in absence of recognized risk or pneumothorax (path P), antineutrophil cytoplasm antibodies (ANCA) positive vasculitis (path V), cervical artery dissection (path A), Periodic acid-Schiff (PAS) positive bodies in the liver cell or unexplained abnormal transaminase level (Path L) [index cases: IC] and (ii) subjects with low-serum alpha1-globulin (path e) and close relatives of patients with AAT deficiency (path r) [non index cases: NIC]. We determined and compared gender, age, AAT serum levels values, the ratio between AAT deficiency subjects identified and all subjects examined (identified/examined). Receiver operating characteristic (ROC) curve was plotted to find the best threshold for AAT serum levels.

RESULTS

Two hundred and eighty-five individuals were examined and 211 with AAT deficiency identified: 66 were IC and 145 NIC. The ratio identified/examined resulted 0.74. A serum level of 120 mg/dL was able to identify AAT deficiency with a specificity of 73% and a sensitivity of 97%. IC showed male prevalence (P=0.005), more advanced age (P=0.02), lower AAT serum levels (P=0.008).

CONCLUSIONS

Our protocol is effective to detect AAT deficiency in a selected population. About 120 mg/dL (nephelometric method) is a reliable AAT serum level cut-off for selecting subjects/patients to submit to phenotype or genotype; as compared to NIC, IC are older, mostly male and with lower AAT serum levels.

A systematic review of the risk factors for cervical artery dissection

BACKGROUND AND PURPOSE

Cervical artery dissection (CAD) is a recognized cause of ischemic stroke among young and middle-aged individuals. The pathogenesis of dissections is unknown, although numerous constitutional and environmental risk factors have been postulated. To better understand the quality and nature of the research on the pathogenesis of CAD, we performed a systematic review of its risk factors.

METHODS

PubMed [MEDLINE (1966 to February 22, 2005)] and Embase (1980 to February 22, 2005) were searched to identify studies fulfilling the inclusion criteria. Two reviewers independently assessed methodological quality of the primary studies. Relevant data were extracted, including the risk factor(s) investigated, characteristics of the study population, and strength of the association(s).

RESULTS

Thirty-one case-control studies were included for analysis. Selection bias, lack of control for confounding, and inadequate method of data analysis were the most common identified methodological shortcomings. Strong associations were reported from individual studies for the following risk factors: aortic root diameter >34 mm (odds ratio [OR=14.2; 95% confidence interval [CI], 3.2 to 63.6), migraine (ORadj, 3.6; 95% CI, 1.5 to 8.6), relative diameter change (>11.8%) during the cardiac cycle of the common carotid artery (ORadj, 10.0; 95% CI, 1.8 to 54.2), and trivial trauma (in the form of manipulative therapy of the neck) (ORadj, 3.8; 95% CI, 1.3 to 11). A weak association was found for homocysteine (2 studies: ORcrude, unknown; 95% CI, 1.05 to 1.52; ORcrude, 1.3; 95% CI, 1.0 to 1.7), and recent infection (ORadj, 1.60; 95% CI, 0.67 to 3.80). Two studies had conflicting findings for low levels of alpha1-antitrypsin, with the methodologically stronger study suggesting no association with CAD.

CONCLUSIONS

CAD is a multi-factorial disease. Many of the reviewed studies contained 2 or more major sources of bias commonly found in case-control studies. Only one study (of homocysteine) used healthy controls, a robust sample size, and had a low risk of biased results. The relationship between atherosclerosis and CAD has been insufficiently examined.