Right ventricular insufficiency

Description:

Until recently function of a right ventricle was in a shadow of large-scale researches of function of a left ventricle. However recently importance of a right ventricle became obvious. Originally researchers tried to extrapolate the data obtained about a left ventricle to a right ventricle, but it became from the very beginning clear that the left and right ventricles considerably differ in many parameters.

Historically the understanding of function of a right ventricle was limited to perception of kontraktilny function of a right ventricle as hemodynamically insignificant. Now right ventricular insufficiency is widely discussed among professional communities, however, numerous questions concerning this subject are not investigated fully. In many respects it is caused by distinctions in approaches of assessment and the analysis of function of a right ventricle, lack of standards and basic knowledge. This review – attempt to systematize the available data, to isolate the most important aspects of right ventricular insufficiency, to define the further directions for researches.

Symptoms of Right ventricular insufficiency:

Precursory symptoms of right ventricular insufficiency are persistent tachycardia, puffiness or pastosity of shins, especially by the end of the day walked and increase in a liver.

Hypostases of hypodermic cellulose in process of increase of right ventricular insufficiency become more resistant and considerable and rise above, extending to hips, a waist, an abdominal wall, in rare instances - to upper extremities. Hypostasis is inclined to shift down therefore at the persons who are carrying out day with the lowered legs legs swell more, and lying patients have an area of a sacrum. Accumulation of liquid happens in serous cavities. The hydrothorax can be bilateral or only right-hand. Ascites is observed more often at is long the existing right ventricular insufficiency. If insufficiency is connected with chronic cardial compression, then early developing and considerable expressiveness of ascites is characteristic. The hydrocardia is seldom expressed so to be defined clinically or to cause a tamponade. The inflammatory reation from serous covers is not observed; transudate contains not enough protein and has low relative density in comparison with an inflammatory exudate.

The increased liver is usually painful at a palpation. Sharp pains in right hypochondrium can be connected with stretching of the hepatic capsule and are more characteristic of incontinuously existing or quickly increasing insufficiency. Significant increase in a liver is followed by heavy feeling in right hypochondrium. Function of a liver usually remains satisfactory though perhaps some increase in a bilirubinemia and activity of transaminases. At long and heavy right ventricular insufficiency liver fibrosis (cardial cirrhosis) can develop. At the same time the liver edge is condensed, its sizes become more constant, at certain patients jaundice gradually develops. In rare instances there can be acute necroses of a liver with considerable jaundice and a liver failure.

Cold extremities, Crocq's disease, expansion of cervical veins attract attention. In an initial stage of a vein bulk up only in a prone position; in process of increase of venous pressure they remain bulked up and in a sitting position. Increase in venous pressure can be measured in an elbow or subclavial vein by means of a flebotonometr. When pressing the venous pressure and swelling of cervical veins increase by a liver. Time of a blood-groove is increased.

Constant symptoms of right ventricular insufficiency are никтурня, an oliguria. The small or moderate proteinuria is often observed. In rare instances the proteinuria exceeds 10 g/l. Congestive gastritis can be shown by a loss of appetite, nausea, pain in epigastriums and to interfere with drug intake. Emergence of symptoms of a hypoxia of a brain is possible.

Reasons of Right ventricular insufficiency:

From the very beginning it should be noted that "true", or primary,  right ventricular insufficiency comes to light extremely seldom and, in most cases, it is connected with inborn heart diseases. Secondary  right ventricular insufficiency is associated with a wide range of diseases of both the cordial, and not cordial nature. Generally, right ventricular insufficiency is a consequence of various pathogenetic ways, finally leading to an adaptation failure: to clinical manifestations, complications, wrong diagnoses and to all volume what, unfortunately, clinical physicians are afraid of. Thus,  right ventricular insufficiency can be presented as a syndrome with various etiology. We found the fullest classification of the etiological reasons at Haddad et al. Also in this work the table of patognomichny markers of dysfunction of a right ventricle in combination with the clinical status and the forecast is offered. All reasons considered in Haddad classification are predictors of physical impossibility of reductions of a right ventricle in these hemodynamic conditions. Clinical physicians, as a rule, face a combination of the reasons resulting in acute right ventricular insufficiency,  this state is especially urgent for a heart surgery, anesthesiology and resuscitation.

Right ventricular insufficiency is associated with a set of diseases and pathological processes, including the pulmonary hypertensia caused by diseases of a pulmonary parenchyma and/or diseases of vessels of easy (cor pulmonale). Other diseases leading to right ventricular insufficiency with various pathogeny include: total, left ventricular or right ventricular cardiomyopathy; right ventricular ischemia and/or heart attack; diseases tricuspid and/or valve of a pulmonary artery; left-right shunts. It is also necessary to allocate especially transplantation of heart as a state with the complicated approach. A. V. white hares et al. in the researches were defined that the postoperative stress at operations of a pneumonectomy causes functional myocardial insufficiency. Also it was established that the level of a kreatinfosfokinaza (KFK) and the cordial emission (CE) directly correlate with a post-operational depression of a myocardium of a right ventricle and lasting adaptations of a right ventricle.

In clinical practice the chronic left ventricular failure is the most common cause of dysfunction of a right ventricle. The left ventricular failure can provoke right ventricular via various mechanisms:

    * the left ventricular failure increases an afterload through increase in venous pulmonary and, especially, arterial pulmonary pressure

    * cardiomyopathic changes of a myocardium can affect also a right ventricle

    * ischemia can also extend to both ventricles

    * left ventricular dysfunction can lead to decrease in systolic pressure of filling in the coronary pool of a right ventricle which, in turn, can be a significant determinant of right ventricular function

    * development of the mechanism of ventricular interdependence against the background of partition dysfunction

    * dilatation of a left ventricle in a limited pericardiac kompartment can lead to disturbance of diastolic function of a right ventricle.

On the other hand, the overload is capable to compromise with the volume of a right ventricle which can happen in situations with pulmonary hypertensia function of a left ventricle and, respectively, to result in insufficiency of a left ventricle. Besides, at the decompensation of a right ventricle provoked by a left ventricular failure, support of a volume flow necessary for adequate preloading becomes an impracticable task. Owing to complex influence on a right ventricle from a left ventricle, assessment of a condition of a right ventricle can be the sensitive indicator of the forthcoming decompensation or the bad forecast.

Pulmonary hypertensia is the reason of right ventricular insufficiency, the second for the importance. The reconsidered classification of pulmonary hypertensia was accepted at the third world conference in Venice in 2003 (Third World Conference in Venice). This classification divides pulmonary hypertensia into cases in which initially are surprised:

    * pulmonary arteries (arterial pulmonary hypertension)

    * pulmonary venous system, and

    * cases of defeat of pulmonary vessels in connection with diseases of lungs, hypoventilations, TELA

At last, insufficiency of a right ventricle is combined with a wide range of congenital anomalies, such as, Fallo's tetrad, a transposition of the main vessels, Ebstein's anomaly, Eyzenmenger's syndrome and others.

Treatment of Right ventricular insufficiency:

For the address back of this potentially deadly process it is necessary to reveal potentially reversible etiology. Haddad et al. consider the general mechanism of therapy of right ventricular insufficiency and analyze the existing strategy. In general, authors adhere to the different points of view in this respect. One take for a starting point function of a right ventricle, others – interrelation of the right and left ventricles, the third – function of a right ventricle in close connection with a pulmonary artery.

The combined approach has to be based on simultaneous elimination of inductors and syndromal therapy. For the solution of a question of the choice of therapeutic approach we originally have to decide on effect which we want to reach. However this time there is a mass of the contradictions demanding the fastest review. The block of problems is connected with "nonideal" diagnosis. Wrong diagnoses lead eventually to irreversible states therefore timely diagnosis of right ventricular insufficiency is a paramount task for the clinical physician. Prevention – the best treatment! From here and efforts of many surgeons to find suitable technology of operation for this disease. Observations about increase in survival of patients with pulmonary hypertensia and an open oval window led to a hypothesis that the atrial septostomiya which leads  to a decompression of a right ventricle and increase in the shunt from right to left can be useful at right ventricular insufficiency. Reaction to a septostomiya at pulmonary hypertensia strongly varies. And at the moment this operation needs to be considered as palliative.

Masami Takagaki et al. in the research of inborn defects with a resistant overload the volume of a right ventricle found out: the procedure of a total exception of a right ventricle provides effective loading with volume, recovers a cylindrical form and improves systolic function of a left ventricle that as a result  leads to increase in cordial emission. They consider this procedure perspective for patients with the isolated dekompensirovanny right ventricular insufficiency caused by an overload volume.

Frigiola et al. used opposite approach – operation on restoration of a right ventricle during implantation of the valve of a pulmonary artery. They position this operation as the safe, simple and effective procedure which can be combined with operation of implantation  of the valve of a pulmonary artery at patients with serious dilatation of a right ventricle and аневризматичеким / the akinetic taking-out path of a right ventricle. Authors consider that in case of insufficiency of a right ventricle in combination with dilatation the concept "valve ventricle" is necessary. This received in a research encourage, however the bigger number of cases of observations and longer terms are required to confirm validity of their approach. The current therapeutic strategy directed to elimination of pulmonary vasoconstriction, cellular proliferation and trombotichesky factors put the task improvement of quality of life and increase in survival of bigger number of patients with heavy pulmonary arterial hypertension.

Just as therapy with use of the agents reducing an afterload, antagonists of β-receptors, inotrop and diuretics improves the functional status and the forecast at patients with a left ventricular failure. Moreover, good sensitivity to pulmonary vazodilatator is associated with the best forecast and survival of patients with high degree of heart failure.  Unfortunately, decrease in an afterload cannot be reached in many cases. Other opportunities as, for example, the thickening of a wall of a right ventricle or leaving from the fetalis program of an expression of genes for the present were not investigated as potential treatment. Continuous intravenous infusion of an epoprostenol at patients with pulmonary hypertensia improves function of a right ventricle. Also as well as use of the non-selective antagonist of endotelinovy receptors of a bozentan leads to similar improvement of function of a right ventricle that is confirmed echocardiographic.

Nevertheless, specific effects and effects for a myocardium after use of these medicines are up to the end not studied. Anyway, in clinical practice first of all it is necessary to normalize the volume and function of the left departments. The right ventricle submits to own law of Starlinga, and in spite of the fact that dysfunction of a right ventricle usually demands bigger volume for adequate filling of the left half of heart, restretching of a right ventricle also worsens its function. Rational use of positive pressure at the end of an exhalation (PEEP) for the purpose of a raspravleniye of atelectases and a hyperventilation can lower a contribution of the pulmonary vasoconstriction caused by a hypoxia and a giperkarbiya. Use of intravenous vazodilatator (Sodium nitroprussidum, nitroglycerine, Tolazolinum (PGI2), гидралазин, prostacyclin, adenosine, никардипин, etc.) for reduction of pulmonary vascular resistance  it is often limited to system hypertensia. Inotropic means (most often милринон which also has also vazodilatiruyushchy effect) can be useful. As intravenous vasodilators not of a selektivna to pulmonary vessels, perhaps, their local introduction can be more effective in decrease in pulmonary vascular resistance without system hypotension. Inhalations of nitrogen oxide (NO) and PGI2 have comparable effect. Such therapy can also improve oxygenation by means of shunting of blood in the ventilated departments of lungs.

And at the end about implantation of an artificial ventricle and transplantation. At patients with acute right ventricular insufficiency, refractory to medicamentous therapy, mechanical support with use of an artificial right ventricle can serve as the bridge to transplantation or recovery. The most general the indication to use of the supporting device is: the right ventricular insufficiency associated with an artificial left ventricle, transplantation of heart, massive TELA.  Use of the supporting device on a constant basis at patients with high degree of right ventricular insufficiency is not studied so far. Trumble et al. describes initial tests on pigs of the temporary right ventricular supporting device which works by the principle of a direct compression of a right ventricle. The system represents  the blinobrazny silicone cylinder (5 cm in the diameter) connected to the console drive which provides 65-ml pneumatic pulse during a heart systole. In the research they came to a conclusion that this method, a so-called kopulsation, is effective for short-term support of a right ventricle. However it is difficult to believe that this device can compete with the pompovy supporting devices and in the future can have though any use.

Transplantation of heart can be considered at certain patients from right ventricular insufficiency, progressing and refractory to other therapy. Originally was considered that such patients with right ventricular insufficiency,  secondary to pulmonary hypertensia can be candidates only for transplantation of a complex heart lungs. However, in connection with shortage of bodies, change of lungs was made by much patients and with good result. One-year survival of patients with pulmonary hypertensia and transplantation of lungs makes ≈ 65% - 75%.  Predictors of resistant right ventricular insufficiency after transplantation of lungs are at the moment not studied adequately. Patients with difficult inborn heart diseases in combination with pulmonary hypertensia need to be considered as candidates for transplantation heart lungs. Patients with refractory right ventricular insufficiency in combination with a left ventricular failure or patients with an aritmogenny dysplasia of a right ventricle and a refractory tachyarrhythmia can be considered for transplantation of heart even in the absence of serious pulmonary hypertensia.

In recent years there was a set of works with use of stem cells. Thousands of researchers constantly work with big enthusiasm on this subject. The majority of works, of course, belong to researches of a left ventricle. Perhaps, in the near future scientists will achieve success, then we will be able to discuss alternative techniques of treatment of right ventricular insufficiency.