Morphology of vascular, renal, and heart lesions in the antiphospholipid syndrome: relationship to pathogenesis

Heart Valve Involvement in Patients with Antiphospholipid Syndrome: A Long-Term Follow-Up Study of a Single Centre

BACKGROUND

Valve involvement is the most common cardiac manifestation in antiphospholipid syndrome (APS). The objective of the study was to describe the prevalence, clinical and laboratory features, and evolution of APS patients with heart valve involvement.

METHODS

A retrospective longitudinal and observational study of all APS patients followed by a single centre with at least one transthoracic echocardiographic study.

RESULTS

144 APS patients, 72 (50%) of them with valvular involvement. Forty-eight (67%) had primary APS, and 22 (30%) were associated with systemic lupus erythematosus (SLE). Mitral valve thickening was the most frequent valve involvement present in 52 (72%) patients, followed by mitral regurgitation in 49 (68%), and tricuspid regurgitation in 29 (40%) patients. Female sex (83% vs. 64%; p = 0.013), arterial hypertension (47% vs. 29%; p = 0.025), arterial thrombosis at APS diagnosis (53% vs. 33%; p = 0.028), stroke (38% vs. 21%; p = 0.043), livedo reticularis (15% vs. 3%; p = 0.017), and lupus anticoagulant (83% vs. 65%; p = 0.021) were more prevalent in those with valvular involvement. Venous thrombosis was less frequent (32% vs. 50%; p = 0.042). The valve involvement group suffered from higher mortality (12% vs. 1%; p = 0.017). Most of these differences were maintained when we compared patients with moderate-to-severe valve involvement (n = 36) and those with no or mild involvement (n = 108).

CONCLUSIONS

Heart valve disease is a frequent manifestation in our cohort of APS patients and is associated with demographic, clinical and laboratory features, and increased mortality. More studies are needed, but our results suggest that there may be a subgroup of APS patients with moderate-to-severe valve involvement with its own characteristics that differs from the rest of the patients with mild valve involvement or without valve involvement.

Mechanisms of Endothelial Dysfunction in Antiphospholipid Syndrome: Association With Clinical Manifestations

The endothelium is a monolayer of cells that covers the inner surface of blood vessels and its integrity is essential for the maintenance of vascular health. Endothelial dysfunction is a key pathological component of antiphospholipid syndrome (APS). Its systemic complications include thrombotic endocarditis, valvular dysfunction, cerebrovascular occlusions, proliferative nephritis, deep vein thrombosis, and pulmonary embolism. In women, APS is also associated with pregnancy complications (obstetric APS). The conventional treatment regimens for APS are ineffective when the clinical symptoms are severe. Therefore, a better understanding of alterations in the endothelium caused by antiphospholipid antibodies (aPL) may lead to more effective therapies in patients with elevated aPL titers and severe clinical symptoms. Currently, while in vivo analyses of endothelial dysfunction in patients with APS have been reported, most research has been performed using in vitro models with endothelial cells exposed to either patient serum/plasma, monoclonal aPL, or IgGs isolated from patients with APS. These studies have described a reduction in endothelial cell nitric oxide synthesis, the induction of inflammatory and procoagulant phenotypes, an increase in endothelial proliferation, and impairments in vascular remodeling and angiogenesis. Despite these lines of evidence, further research is required to better understand the pathophysiology of endothelial dysfunction in patients with APS. In this review, we have compared the current understanding about the mechanisms of endothelial dysfunction induced by patient-derived aPL under the two main clinical manifestations of APS: thrombosis and gestational complications, either alone or in combination. We also discuss gaps in our current knowledge regarding aPL-induced endothelial dysfunction.

Renal Involvement in Antiphospholipid Syndrome

Antiphospholipid syndrome is a complex autoimmune disease, characterized by the presence of vascular thrombosis, obstetric, hematologic, cutaneous, and cardiac manifestations. Renal disease in patients with antiphospholipid syndrome was not recognized in the first descriptions of the disease, but later on, the renal manifestations of the syndrome have been investigated widely. Renal manifestations of antiphospholipid syndrome conform a wide spectrum of diverse renal syndromes. Hypertension is one of the most frequent, but less commonly recognized renal alteration. It can be difficult to control as its origin is renovascular. Renal vascular thrombosis can be arterial or venous. Other alterations are renal infarction and vascular thrombosis in arterial territories. Venous thrombosis can be present in primary and secondary antiphospholipid syndrome; it presents with worsening of previous proteinuria or de novo nephrotic syndrome, hypertension and renal failure. Antiphospholipid syndrome nephropathy is a vascular disease that affects glomerular tuft, interstitial vessels, and peritubular vessels; histopathology characterizes the renal lesions as acute or chronic, the classic finding is thrombotic microangiopathy, that leads to fibrosis, tubule thyroidization, focal cortical atrophy, and glomerular sclerosis. Antiphospholipid syndrome nephropathy can also complicate patients with systemic lupus erythematosus, and there is vast information supporting the worse renal prognosis in this group of patients with the classic histopathologic lesions. Treatment consists of anticoagulation, as for other thrombotic manifestations of antiphospholipid syndrome. There is some evidence of glomerulonephritis as an isolated lesion in patients with antiphospholipid syndrome. The most frequently reported glomerulonephritis is membranous; with some reports suggesting that immunosuppressive treatment may be effective. Patients with end stage renal disease commonly are positive for antiphospholipid antibodies, but it is not clear what is the role of aPL in this setting. Patients with vascular access may have complications in the presence of antibodies so that anticoagulation is recommended. Patients ongoing renal transplant with persistent antiphospholipid antibody positivity may have early and late graft failure.

Vascular Manifestations in Antiphospholipid Syndrome (APS): Is APS a Thrombophilia or a Vasculopathy?

PURPOSE OF REVIEW

Antiphospholipid antibody syndrome (APS) is characterized primarily by thrombosis and pregnancy morbidity. Chronic vascular lesions can also occur. While the underlying mechanisms of these vascular lesions are not entirely known, there have been multiple theories describing the potential process of vasculopathy in APS and the various clinical manifestations associated with it.

RECENT FINDINGS

Recently, it has been demonstrated that endothelial proliferation in kidneys can be explained by the activation of the mammalian target of rapamycin complex (mTORC) pathway by antiphospholipid antibodies (aPL). These data support the existence of an APS-related vasculopathy in different locations which can explain-in part-the different manifestations of APS. This review focuses on the various manifestations of APS as a result of APS-related vasculopathy, as well as pathophysiology, current screening, and treatment options for clinicians to be aware of.

Kidney disease in primary anti-phospholipid antibody syndrome

APS is an autoimmune disease defined by the presence of arterial or venous thrombotic events and/or pregnancy morbidity in patients who test positive for aPL. APS can be isolated (primary APS) or associated with other autoimmune diseases. The kidney is a major target organ in APS, and renal thrombosis can occur at any level within the vasculature of the kidney (renal arteries, intrarenal vasculature and renal veins). Histological findings vary widely, including ischaemic glomeruli and thrombotic lesions without glomerular or arterial immune deposits on immunofluorescence. Renal involvement in patients with definite APS is treated with long-term anticoagulants as warfarin, but new treatments are being tried. The aim of this article is to review the links between primary APS and kidney disease.

Echocardiographic findings in asymptomatic systemic lupus erythematosus patients

The aim of this study is to use transthoracic echocardiographic (TTE) imaging methods to identify cardiac dysfunction in asymptomatic systemic lupus erythematosus (SLE) patients and to determine the association between echocardiographic findings and serology. This is a prospective cross-sectional study where 50 patients with confirmed diagnoses of SLE were recruited from rheumatology outpatient clinics. Clinical and serological evaluation to confirm the diagnosis of lupus was done in all patients. Fifty SLE patients, 46 (92%) females and 4 (8%) males, were recruited. Anti-double-stranded DNA (Anti-dsDNA), anticardiolipin, lupus anticoagulant, and anti-β2-glycoproteins were positive in 52.1, 32.6, 13.3, and 15.6%, respectively. Transthoracic echocardiogram revealed mitral regurgitation in 16 patients (32%), pericardial effusion in16 patients (32%), aortic regurgitation in five patients (10%), and tricuspid regurgitation in 10 patients (20%). Eleven patients had left ventricular hypertrophy (22%), and eight patients had ventricular systolic dysfunction (16%). Only four patients had ventricular diastolic dysfunction (8%). A significant association between mitral and tricuspid valve regurgitation and positive anti-dsDNA (p < 0.018, p < 0.006, respectively) was found. Positive anticardiolipin antibodies, lupus anticoagulant, and anti-β 2 glycoprotein antibodies were also associated with mitral valve regurgitation (p values 0.044, 0.006, and 0.023), respectively. Active disease assessed by Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) was found to be associated with increased risk of mitral valvular leaflet thickening (p value 0.028). Performing regular transthoracic echocardiogram in asymptomatic SLE patients is important for early detection and appropriate treatment of cardiac lesions. Clinically quiescent but serologically active disease and presence of antiphospholipid antibodies were associated with structural heart abnormalities.

What do we know about the cardiac valve lesion in the antiphospholipid syndrome (APS)?

Heart valve disease (HVD) is the most common cardiac manifestation in the antiphospholipid syndrome (APS). Valve lesions should be described according to the established definition. HVD is progressive despite anticoagulant/antiplatelet treatments. Around 4–6% of patients with HVD in APS will require valve replacement surgery, which is considered a very high risk procedure in APS. Unfortunately, no recommendations regarding medical treatment of antiphospholipid antibodies-associated HVD can be made at this moment. There are evidence-based data and strong pathophysiologic rationale for considering HVD as a manifestation of APS. Thus, HVD should be included as a criterion of definite APS.

Renal involvement in antiphospholipid syndrome

Antiphospholipid syndrome (APS) is an autoimmune disease defined by the presence of arterial or venous thrombotic events and/or pregnancy morbidity in patients who test positive for antiphospholipid antibodies (aPLs). APS can be isolated (known as primary APS) or associated with other autoimmune diseases, such as systemic lupus erythematosus (SLE; known as secondary APS). The kidney is a major target organ in APS and renal thrombosis can occur at any level within the vasculature of the kidney (renal arteries, intrarenal arteries, glomerular capillaries and renal veins); events reflect the site and size of the involved vessels. Histological findings vary widely, including ischaemic glomeruli and thrombotic lesions without glomerular or arterial immune deposits on immunofluorescence. Renal prognosis is affected by the presence of aPLs in patients with lupus nephritis and can be poor. In patients with SLE and aPLs, biopsy should be performed because inflammatory and thrombotic lesions require different therapeutic approaches. Renal involvement in patients with definite APS is treated by anticoagulation with long-term warfarin. The range of renal manifestations associated with APS is broadening and, therefore, aPLs have increasing relevance in end-stage renal disease, transplantation and pregnancy.

Sixth meeting of the European Forum on antiphospholipid antibodies. How to improve the understanding of the antiphospholipid syndrome?

The main objective of these meetings is to promote international collaboration in various clinical and research projects. This paper is the summary of the 2007 Ljubljana meeting, and offers an overview of the proposed projects. The technical and methodological details of the projects will be published on the forum’s web site (http://www.med.ub.es/MIMMUN/FORUM/STUDIES.HTM).

Antiphospholipid syndrome and the kidneys

OBJECTIVES

To study the relationship between antiphospholipid antibodies and kidney diseases.

METHODS

We reviewed the medical literature from 1968 to 2005 using MEDLINE and the keywords antiphospholipid syndrome, anticardiolipin antibodies, lupus anticoagulant, hypertension, renal artery stenosis, renal vascular thrombosis, thrombotic microangiopathy, and glomerulonephritis.

RESULTS

The renal manifestations of the antiphospholipid syndrome may result from thrombosis occurring at any location within the renal vasculature, that is, in the renal artery trunk or branches, intraparenchymal arteries and arterioles, glomerular capillaries, and the renal veins. The spectrum of these manifestations includes renal artery stenosis and/or malignant hypertension, renal infarction, renal vein thrombosis, thrombotic microangiopathy, increased allograft vascular thrombosis, and reduced survival of renal allografts. More recently nonthrombotic conditions like glomerulonephritis have also been reported.

CONCLUSION

The kidney appears to be a major target organ in both primary and secondary APS. Early detection of renal involvement may improve the prognosis of these patients.

A unique presentation of antiphospholipid antibody syndrome in pregnancy

Primary antiphospholipid antibody syndrome (APS) is a protean disease with many manifestations including venous and arterial thrombosis, recurrent foetal loss, preeclampsia, intrauterine growth retardation, cardiac valvular disease, glomerulonephritis, thrombocytopaenia and livedo reticularis. We report an interesting case of a 19-year-old woman where the diagnosis of primary APS was initially made in the peripartum period.

Antiphospholipid Syndrome: Review

Antiphospholipid syndrome spans many medical disciplines. Classic criteria include the presence of anticardiolipin antibody or lupus anticoagulant with typical complications of thrombosis or pregnancy loss. Other common associated manifestations include livedo reticularis, thrombocytopenia, valvular heart disease, and nephropathy with renal insufficiency, hypertension, and proteinuria. Treatment of serious complications with anticoagulation is standard; generally warfarin for thrombosis and aspirin/heparin for pregnancy prophylaxis. Detailed recommendations regarding precise intensity and duration of anticoagulation are still a subject of debate.

Catastrophic antiphospholipid syndrome: A rare cause of disseminated microvascular thrombotic injury - a case report with pathological and molecular correlative studies

Catastrophic antiphospholipid syndrome (CAPS) is a severe and rare variant of antiphospholipid syndrome (APS) characterized by acute multiorgan failure due to small vessel thrombi in patients with positive antiphospholipid antibodies. We report a fatal case of catastrophic antiphospholipid syndrome in a young woman with a history of polymyositis and Hodgkin lymphoma. The patient was admitted to hospital because of severe foot pain following several weeks of skin ulcerations. Doppler ultrasonography showed evidence of arterial ischemia of the both lower extremities. Despite anticoagulation, immunosuppression, plasmapheresis and antibiotic therapy, she developed cutaneous gangrene, retroperitoneal hematoma, ileus, and acute respiratory and renal failure that resulted in death. Autopsy showed multifocal vascular injury and microthrombi with associated hemorrhages and infarcts in multiple organs. The patient had normal levels of functional protein C and protein S and a normal level of plasma homocysteine. Tests for common thromophilic gene mutations including prothrombin 20210, factor V Leiden 1691, and methylene tetrahydrofolate reductase 677 were negative. To our knowledge, this is the first CAPS patient with molecular studies for genetic prothrombotic mutations. Our report showed that there was no association between the development of CAPS and inherited thromophilia.

Nodular regenerative hyperplasia (NRH) of the liver--a manifestation of 'organ-specific antiphospholipid syndrome'?

Nodular regenerative hyperplasia (NRH) of the liver is a local hyperplastic response of hepatocytes, probably due to vascular abnormalities. Since it was shown in a few case reports that NRH may be associated with antiphospholipid antibodies (APA) we wanted to analyze the relevance of APA in patients with this disease. Sera from 13 patients with histologically defined NRH were tested for APA by an in-house ELISA using as antigens cardiolipin (CL), beta2-glycoprotein I (beta2-gp I), phosphatidylserine (PS), and thromboplastin (TP), a mixture of different phospholipids and phospholipid-binding proteins. As controls, sera from patients with serologically and histologically defined autoimmune liver diseases (primary biliary cirrhosis n = 14; autoimmune hepatitis n = 14) without histological evidence for NRH as well as from 14 healthy blood donors were analyzed. 77% of the NRH patients had APA. In 46% they were directed against CL. In contrast, only 14% of the patients with autoimmune liver diseases and 14% of the healthy controls had anti-CL antibodies (p < 0,05). Antibodies to beta2-gp I and TP did not discriminate between NRH and autoimmune liver diseases. Anti-PS antibodies were not observed. These data indicate that determination of anti-CL antibodies in NRH may help to identify a subgroup of patients in whom an 'organ-specific antiphosholipid syndrome' of the liver may be involved in the pathogenesis.