Chronic heart failure in pregnancy

According to the WHO definition, heart failure in pregnancy is the inability of the heart to supply blood to the body tissues in accordance with metabolic needs at rest and / or with moderate physical exertion. The main manifestations of heart failure are a decrease in the tolerance of physical activity and a delay in the body of the fluid.

Heart failure (CH) is a natural and most severe complication of various diseases of the cardiovascular system (congenital and acquired heart defects, coronary heart disease, acute myocarditis and cardiomyopathies, infective endocarditis, arterial hypertension, cardiac rhythm and conduction disorders).

At the heart of the onset and progression of heart failure in pregnancy are two interrelated pathophysiological mechanisms - heart remodeling (which refers to the totality of changes in the shape and magnitude of the cavity and mass of the ventricles, as well as the structure, ultrastructure and metabolism of the myocardium) and the activation of neurohumoral systems and, sympatoadrenal (CAC), renin-angiotensin (RAS), endothelin and vasopressin.

Pregnancy contributes to the development and progression of heart failure, which is due to significant changes in hemodynamics (increased bcc, heart rate, total peripheral resistance, the appearance of an additional placental circulatory system), the acceleration of metabolic processes, expressed endocrine and neurohumoral shifts. Most often, the onset and growth of heart failure occur within a period of 26-32 weeks. Pregnancy, that is, during the period of maximum hemodynamic load, and also in the postpartum period.

[1], [2], [3], [4]

Symptoms of heart failure in pregnancy

Clinical symptoms of heart failure in pregnancy are varied. They include signs that indicate a decrease in exercise tolerance and fluid retention in the body. About stagnation in the small circle of blood circulation is indicated by shortness of breath, acrocyanosis, cardiac asthma; in a large circle - an increase in the liver, swelling and pulsation of the jugular veins, ascites, edema, nocturia.

Acute congestive heart failure - pulmonary edema

Acute heart failure during pregnancy is a serious threat to the life of the pregnant woman and the mother in childbirth. Most often, it develops according to the type of left ventricular failure - cardiac asthma or pulmonary edema.

Pulmonary edema is an acute increase in the hydration of the lungs due to the penetration of fluid from the capillaries into the interstitial tissue and the alveoli, leading to a disruption in their ventilation.

Pathophysiological mechanisms of pulmonary edema development are:

• the buildup of hydrostatic pressure in the pulmonary capillaries;
• decreased oncotic blood pressure;
• increased permeability of alveolar-capillary membranes;
• violation of lymphatic drainage of lung tissue.

According to the first mechanism, cardiogenic pulmonary edema develops (that is, left heart failure proper), three others are characteristic of non-cardiogenic pulmonary edema.

Pregnancy in patients with women significantly increases the risk of pulmonary edema, which is associated with the peculiarities of hemodynamics (a significant increase in bcc) and neurohumoral regulation mechanisms, a tendency to fluid retention and sodium, dysfunction of cell membranes, constant psychoemotional stress, relative hypoproteinemia, leading to a decrease in oncotic blood pressure, and insufficient outflow of lymph associated with mechanical factors, in particular, with a high diaphragm standing.

Cardiogenic pulmonary edema is the most frequent variant, which is the result of acute deficiency of the left heart, arising from various cardiac pathologies, acquired and congenital heart defects, acute myocarditis, cardiomyopathy, large-focal cardiosclerosis, arterial hypertension, etc. Most often in pregnant women, pulmonary edema develops with mitral stenosis, the main pathogenetic factor of development of which is hypervolemia.

There are four stages of development of pulmonary edema:

• I stage - there is only peribronchial edema;
• II stage - liquid accumulates in interalveolar septa;
• II (stage - liquid swims into the alveoli;
• IV (final) stage - the volume of the interstitial fluid increases by more than 30% of the initial level and it appears in the large bronchi and trachea.

In accordance with these stages, interstitial (clinically manifested by cardiac asthma) and alveolar edema of the lungs are diagnosed. Rapid and massive sweating of fluid into the alveoli leads to "lightning" pulmonary edema, which is accompanied by asphyxiation and often ends in death. The etiology distinguishes rheumatic and non-rheumatic myocarditis; the latter can be infectious - bacterial, viral, parasitic and in other diseases.

Non-rheumatic myocarditis is a consequence of the direct or indirect effect of infection on the mechanism of allergy or autoimmunization of an infectious or noninfectious factor (drug, serum, food, etc.) on the myocardium.

Cardiosclerosis (myocardiofibrosis) is the final stage of various heart diseases: myocarditis (myocarditis cardiosclerosis), coronary atherosclerosis (atherosclerotic cardiosclerosis), myocardial infarction (postinfarction cardiosclerosis). In pregnant women, there is mainly myocarditis and cardiosclerosis (myocardiofibrosis).

The diagnosis of myocarditis in pregnant women is established on the basis of clinical data (dyspnea, palpitations, pain in the heart, restriction of physical activity, arrhythmia, recognize CH), electro- and echocardiographic studies.

Indications for abortion are:

• acute myocarditis;
• cardiosclerosis with severe rhythm disturbances;
• CH IIA stages and above;
• III-IV FC;
• signs of coronary pathology.

The volume of therapeutic measures for myocarditis: sanation of foci of chronic infection, NSAIDs, antibiotics, glucocorticosteroids (in the absence of the effect of NSAIDs), desensitizing agents, drugs of metabolic action, beta-adrenoblockers.

[5], [6], [7]

Classification of heart failure in pregnancy

The classification of heart failure in pregnancy, approved by the VI National Congress of Cardiologists of Ukraine (2000), includes the definition of the clinical stage, functional class and option.

Clinical stages of heart failure (corresponds to the stage of chronic circulatory failure according to the classification of ND Strazhesko, V. Kh. Vasilenko):

• CH I - latent, or initial;
• CH II - expressed (divided into IIA - the beginning of a long stage and IIB - the end of this stage);
• CH III - the final, dystrophic.

The stage of heart failure during pregnancy reflects the stage of the clinical evolution of this process, while the functional class of the patient is a dynamic characteristic that can change under the influence of treatment.

By the criteria of NYHA, four functional classes (FC) of the patient are distinguished:

• I FC - a patient with a heart condition suffers from usual physical exertion without dyspnea, tired of the remains or palpitations;
• II FC is a patient with a moderate restriction of physical activity, in which shortness of breath, fatigue, palpitation are observed when performing normal physical exertion;
• III FC - there is a significant limitation of physical activity, there are no complaints at rest, but even with minor physical exertion, shortness of breath, fatigue, palpitations occur;
• IV FC - at any level of physical activity and at rest, these subjective symptoms occur.

The majority of pregnant women with cardiac pathology belong to I and II FK, less than 20% of patients - III and IV FC.

Variants of heart failure: with systolic dysfunction - systolic heart failure (ejection fraction, PV <40%), with preserved systolic function - diastolic CH (PV> 40%).

[8], [9], [10], [11], [12],

Diagnosis of heart failure in pregnancy

Diagnosis of heart failure in pregnancy is based on clinical signs, given instrumental research methods that allow to objectify myocardial dysfunction and heart remodeling (EchoCG with Doppler, ECG and radiography), as well as on positive results of treatment aimed at eliminating circulatory disorders.

[13], [14], [15], [16], [17], [18]

Delivery of pregnant women with heart failure

The presence of CH IIA and above stages III and IV of the FC, irrespective of the nature of the heart disease, necessitates a gentle method of delivery: in uncomplicated cases, switching off attempts by the operation of applying obstetric forceps, and in case of an unfavorable obstetrical situation (pelvic presentation, narrow pelvis) delivery by caesarean section.

In CH IIB and CH III stage, it is mandatory to stop lactation, with CH IIA usually exclude night feeding.

[19], [20]

Treatment of heart failure in pregnancy

Treatment of chronic heart failure in pregnant women provides:

• load limitation: with CH IIA - a semi-postal regime and moderate physical activity ("comfortable" motor regimes); with CH IIB and CH III - bed rest and respiratory gymnastics in bed;
• therapy of the underlying disease that caused CH;
• a diet with a limited intake of liquid and sodium chloride (less than 3 g / day at I-II FC and less than 1.5 g / day at III-IV FC).

Medication Therapy

In pregnancy, the most commonly used in the cardiac clinic for the treatment of heart failure are inhibitors of angiotensin-converting enzyme. Preparations of this group cause fetal growth retardation, limb contractures, deformation of the skull and litha, lung hypoplasia, hypo-plague, and even antenatal death. In addition to direct negative effects on the fetus, they lead to spasm of the vessels of the uterine-placental basin, further exacerbating the fetal suffering.

Also blockers of angiotensin II receptors are categorically contraindicated throughout pregnancy.

For the treatment of CHF in pregnant women use drugs of various groups:

• diuretics with obvious clinical signs of fluid retention in the body; the drug of choice is furosemide (40 mg / sug 2-3 times a week);
• cardiac glycosides (digoxin 0,25-0,50 mg / day) are prescribed for tachysystolic form of atrial fibrillation. CH IIA and above the stages, III-IV FC;
• peripheral vasodilators are used in CH with signs of pulmonary congestion: molsidomine 3-8 mg 3 times a day (contraindicated in the I trimester);
• beta-blockers are prescribed for all patients with CHF II-IV FC starting from a minimal dose, gradually increasing it weekly to the target dose: metoprolol or atenolol (from 6.25 to 50 mg), carvedilol (from 3.125 to 25 mg), bisoprolol ( from 1.25 to 10 mg), nebivolol (from 1.25 to 10 mg). When prescribing beta-blockers, it should be remembered that they increase the tone of the uterus and, with the threat of interruption of pregnancy, can cause miscarriage; they also reduce uteroplacental blood flow. One of the proven negative consequences of using beta-blockers during pregnancy is a delay in fetal growth. Given that beta-adrenoblockers can cause bradycardia and hypotension in a newborn, they should stop taking them 48 hours before the birth;
• drugs that normalize the metabolism of the myocardium: riboxin (0.2 g 3 times a day), vitamins, potassium orotate (0.25 -0.5 g 3 times a day), trimetazidine (20 mg 3 times a day).

In the treatment of heart failure in pregnant women with diastolic dysfunction of the left ventricle, verapamil, beta-adrenoblockers are used. It should be discarded (or very limitedly used) from cardiac glycosides, diuretics, nitrates (prescribed for systolic variant of HF).