Features of cardiac lesions in systemic scleroderma

Proposed mechanisms of cardiac pathology in systemic sclerosis (SSc) include ischemic injury, development of myocarditis, progressive fibrosis, systemic hypertension, and pulmonary arterial hypertension (PAH) with development of chronic cor pulmonale.

One of the important hypotheses of cardiac damage in systemic scleroderma is ischemic damage to intramural vessels with the development of fibrinoid necrosis, fibrosis and intimal hypertrophy with narrowing of the lumen, which is manifested by angina pectoris, acute myocardial infarction and sudden death.

Typical morphological changes are linear necrosis of cardiomyocytes, the appearance of which is associated with transient vascular spasm due to local Raynaud's syndrome. Most patients with systemic sclerosis with proven coronary artery disease also have signs of peripheral Raynaud's syndrome.

Along with such mechanisms of ischemic damage in SSD as coronary artery spasm, damage to the microcirculatory bed, occlusive damage to the heart vessels, the contribution of the macrovascular link (coronary arteries) to the development and progression of heart pathology is also discussed. Previously, it was believed that the coronary arteries in systemic sclerosis are intact and cardiosclerosis is not a consequence of angiogenic processes. Currently, thickening of the intima of the coronary vessels, narrowing of their lumen have been shown, which indicates a complex origin of scleroderma cardiosclerosis,

The mechanisms of pulmonary hypertension development in systemic sclerosis are not fully understood. Inflammation is considered to be the main pathogenetic factor. Induration of the vascular wall by macrophages and T-lymphocytes is noted both in primary PAH and in that associated with SSc. Inflammatory cells produce growth factors, such as platelet-derived growth factor, vascular endothelial growth factor, which are of great importance in the pathogenesis of pulmonary hypertension. In patients with systemic sclerosis, antinuclear and antihistone antibodies are associated with vascular lesions.

The traditional concept of pulmonary hypertension development as a result of pulmonary vasoconstriction has undergone significant changes in recent years. However, some authors point out that Raynaud's syndrome is more common in patients with SSc who have pulmonary hypertension than in patients without it, so the authors consider the hypothesis of the existence of the so-called pulmonary Raynaud's syndrome.

In the genesis of pulmonary hypertension in systemic sclerosis, a violation of endothelium-dependent vasodilation has been established, which is associated with a decrease in the activity of endothelial NO synthase. In addition to nitric oxide, endothelial cells produce the vasodilating factor prostacyclin, which is involved in providing antithrombogenic properties of the vascular wall and affects proliferative processes in the intima and adventitia of pulmonary vessels. A decrease in prostacyclin expression has been established in patients with severe pulmonary hypertension associated with SSc.

In complicated pulmonary hypertension SSc, an increase in the vasoconstrictor peptide endothelin-1 is noted, as well as serotonin, especially in severe Raynaud's syndrome. Pulmonary thrombosis in situ is one of the pathogenetic mechanisms of pulmonary hypertension in systemic scleroderma, most often realized in the concomitant antiphospholipid syndrome.

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Symptoms of Heart Damage in Systemic Scleroderma

In systemic scleroderma, damage to all three membranes of the heart has been described: myocardial damage is observed in 83-90%, endocardial damage in 18-35%, and pericardial damage in 13-21% of cases. Multisegmental myocardial perfusion disorders at rest or under load, myocardial fibrosis, and focal cardiosclerosis with signs of progressive chronic heart failure are often detected.

It has been established that in systemic scleroderma with skeletal muscle damage, myocardial pathology occurs in 21% of cases and in 10% of cases in patients without skeletal myopathy.

Clinically expressed myocarditis is rare, which is in dissociation with autopsy data, in which focal or diffuse myocardial fibrosis and linear necrosis of cardiomyocytes are often noted. Features of myocarditis in SSD - the absence of significant pathology of large coronary arteries and frequent damage to the right ventricle and subendocardial myocardium.

Endocardial damage in systemic scleroderma is less common than myocardial damage and is characterized by marginal sclerosis and shortening of the chords of the mitral valve with the development of mitral insufficiency and mitral valve prolapse.

Pericardial changes (fibrinous, adhesive, exudative pericarditis) are observed in 15-20% of patients, and they are associated with the local cutaneous form of systemic scleroderma. Clinical signs: dyspnea, orthopnea and edema. Cardiac tamponade, as a rule, does not develop due to a small pericardial effusion. It should be noted that pericarditis can develop as a primary manifestation of systemic scleroderma, as well as due to uremia. The possibility of developing pancarditis - a combined lesion of the myocardium, pericardium and endocardium with a characteristic predominance of fibrosis processes - has been shown.

The development of systemic arterial hypertension in systemic scleroderma is caused by both renal vascular lesions and iatrogenic (glucocorticoid treatment) causes. The high incidence of interstitial lung disease and the development of PAH creates the preconditions for the development of pulmonary heart disease

The incidence of pulmonary hypertension in patients with systemic sclerosis varies from 0 to 60%. Approximately 33% of patients with diffuse systemic sclerosis have pulmonary hypertension, both isolated and due to interstitial lung disease. In patients with CREST syndrome, PAH is more common (60%). The development of PAH is the cause of death in a number of patients with SSc and largely determines the prognosis for life. The two-year survival rate of patients with CREST syndrome and PAH is 40%, while in the absence of PAH it is 80%.

The main clinical manifestation of pulmonary hypertension in systemic sclerosis is dyspnea during physical exertion. Other symptoms are palpitations, as well as signs of right ventricular failure, primarily edema and ascites. In the last decade, the problem of remodeling of the right heart chambers in PAH has been discussed in domestic and foreign literature. A reliable dependence of the expansion of the right ventricular cavity and hypertrophy of its wall on the degree of PAH, the degree of reduction in ejection fraction and the increase in PAH has been established, which raises the question of the need to identify early signs of heart damage, both right and left, in order to determine the "therapeutic window" for influencing the main mechanisms of progression of systemic sclerosis.

Objective signs of pulmonary hypertension, detected during cardiac auscultation, include accentuation and/or bifurcation of the first tone over the pulmonary artery or its amplification during inspiration. However, they appear only when the pressure in the pulmonary artery increases by 2 times. Pulsation in the second intercostal space on the left, the appearance of systolic and diastolic murmurs are recorded only in severe pulmonary hypertension.

The development of heart damage in systemic scleroderma in most cases occurs gradually, over 4-6 years, but the process steadily progresses, leading to CHF. In 30% of cases, heart damage is the direct cause of death in patients with SSc.

Pathophysiological aspects of cardiac pathology in systemic scleroderma include: cardiac Raynaud's syndrome with vasospasm and microcirculation disorders, accelerated atherogenesis against the background of immune inflammation, development of autoimmune myocarditis, cardiac fibrosis, which underlies the progression of congestive heart failure.

Subclinical cardiovascular involvement is often confirmed by autopsy data.

Clinically significant cardiac involvement in systemic sclerosis, myocardial rhythm and conduction disturbances, ischemia, systemic pulmonary hypertension and congestive heart failure are associated with a poor prognosis.

The presence of chronic pulmonary heart disease determines high disability of patients and is associated with progressive pulmonary arterial hypertension, which dictates the need to develop a modern pathogenetically substantiated treatment for systemic scleroderma complicated by cardiovascular pathology.