Heart Failure (Cardiac Insufficiency): Surgical Therapy

Cardiac resynchronization (cardiac resynchronization therapy, CRT)

Cardiac resynchronization (cardiac resynchronization therapy, CRT) is a new pacemaker procedure to resynchronize cardiac contraction for patients with heart failure (heart failure: NYHA stages III and IV) when drug therapy has been exhausted. This counteracts poor coordination between contraction and relaxation of the ventricles and improves blood flow, exercise tolerance, and quality of life.

In patients with left bundle branch block, the procedure significantly reduces heart failure-related hospitalization (hospitalization) and cardiovascular and all-cause mortality (all-cause mortality rate).
For resynchronization therapy to be successful, the pacing ratio must be as high as possible.

For details on the procedure, see “cardiac resynchronization“.

Implantable left ventricular assist devices (artificial hearts)

Ventricular assist devices are fully or partially implantable mechanical pumps that take over the pumping function of the ventricle to provide adequate blood flow to the patient. Indications are temporary support in acute disease processes – e.g. acute heart failure, myocarditis (inflammation of the heart muscle), pronounced myocardial infarction (heart attack) – or as a bridging device to bridge the waiting period until transplantation. Another indication is the therapy-refractory final stage of left heart failure (left heart weakness). In this case, the only established surgical treatment apart from heart transplantation is the use of a left ventricular assist device (LVAD). This is a temporary mechanical heart replacement. The artificial heart is implanted intrathoracically in the left ventricle and uses a rotary pump to generate continuous flow. It serves:

To bridge the time until heart transplantation (“bridge to transplant”) or.
To unload the cardiopulmonary system, resulting in myocardial remodeling (“bridge to recovery”) or
To bridge the time to eligibility for listing for heart transplantation (“bridge to transplantability”) or
As permanent cardiac support (“destination therapy”).

Indications for possible ventricular-assist-device (VAD) implantation according to the European Society of Cardiology (ESC) guidelines are: (adapted from)

Dependence on intravenous catecholamine therapy.

Progressive secondary organ damage (liver, kidney) on the floor of hypoperfusion rather than hypovolemia (PCWP ≥ 20 mmHg and SBP ≤ 80-90 mmHg or CI ≤ 2 l/min/m2)

Worsening right heart function

Legend

LVEF “left ventricular ejection fraction”.
VO2 “oxygen uptake” (oxygen uptake).
PCWP “pulmonary capillary wedge pressure” (pulmonary capillary wedge pressure).
SBP “systolic blood pressure” (systolic blood pressure).
CI “cardiac index” (cardiac index; quotient of cardiac output and body surface area in square meters).

Patients potentially eligible for implantation of a cardiac assist device (after).

Patients who have had severe symptoms for more than two months despite optimal drug and CRT/ICD therapy and who meet more than one of the following criteria:

LVEF (left ventricular ejection fraction) <25% and, if measured, peak VO2 <12 mL/kg/min.
≥ 3 hospitalizations within the past 12 months without a triggering event.
Need for i.v. inotropic therapy
Progressive end-organ dysfunction (worsened renal and/or hepatic function) attributable to decreased perfusion rather than inadequate ventricular filling pressure (PCWP ≥ 20 mmHg and SBP ≤ 80-90 mmHg or CI ≤ 2 L/min/m2)
No severe right heart failure with severe tricuspid regurgitation

Baroreflex activation therapy (BAT)

In chronic heart failure, there is a pathophysiologically unfavorable constellation of increased sympathetic nerve activity (causes an increase in the performance of the organism under load (stress) (ergotropic effect)) and decreased activity of the parasympathetic nerve (“resting nerve”; serves metabolism, recovery and the build-up of endogenous reserves (trophotropic effect)). This contributes to the symptomatology and progression (progression) of the disease. Baroreflex activation therapy uses an electrical pulse generator to stimulate the baroreceptors (in this case: Mechanoreceptors/pressure sensitive nerves in the wall of the carotid artery) are stimulated by means of an electrical pulse generator. This leads to a positive influence on the autonomic nervous system as described below. As a result, the heart can pump blood through the veins more easily and is spared. Indications: Severely impaired cardiac function (systolic heart failure; ejection fraction < 35%) and symptoms such as dyspnea (shortness of breath) even with mild exertion (NYHA class III); patients with narrow QRS complex The procedure: A small pulse generator is inserted under the collarbone. This device stimulates the baroreceptors (pressure receptors) as if blood pressure is too high. This influences afferent and efferent pathways of the autonomic nervous system in a way that results in a dampening of sympathetic activity and activation of the parasympathetic nervous system (“vagotonic response” = “recovery mode”). This benefits the heart, which has to work less. The procedure is performed in a minimally invasive procedure, usually by a cardiac or vascular surgeon, within about 1.5 hours. In one study, efficacy was assessed as follows:

Improvement in NYHA class in the BAT group significantly more often than in the control group (55 versus 24 percent).
Improvement in quality of life (Minnesota Quality of Life Score) in the BAT group significantly better than the control group (-17.4 versus 2.1 score points).
Increase in walking distance on the 6-minute walk test significantly greater in the BAT group (59.6 versus 1.5 m).

Another study suggests that cardiac resynchronization (cardiac resynchronization therapy, CRT) reduces the imbalance between adrenergic and parasympathetic activity – which would likely minimize the margin of action for BAT. The authors demonstrated that with CRT, the corresponding effects of BAT were much weaker and predominantly nonsignificant.

Surgical restoration of ventricular geometry

Increasing cardiomegaly (enlargement of the heart) and particularly of the left ventricle (heart chamber) as part of the remodeling process in chronic heart failure leads to increasing deterioration of cardiac performance and increasing risk of complications. Surgical reduction of the ventricle or ventricular modification has been introduced with the goal of reducing the size of the ventricles and normalizing the relationship between volume and mass. However, the results of this therapy are highly inconsistent. Therefore, patient selection is reserved for experienced therapeutic centers.

Interatrial shunt

The procedure briefly described below is used in patients with heart failure with preserved ejection fraction (= diastolic heart failure; synonym: diastolic dysfunction; diastole is the slackening and thus blood inflow phase) for whom no evidence-based therapy is yet available. Patients show decreased distensibility (compliance) predominantly of the left ventricle of the heart with normal systolic pump function, i.e., ejection fraction > 50%, (“heart failure with preserved ejection fraction” (HFpEF), elevated natriuretic peptides and echocardiographic evidence of diastolic dysfunction. Interventional therapy is used to achieve decompression by creating a left-right shunt between the two atria (= interatrial shunt). For this purpose, a catheter is used to create a small opening in the interatrial septum, which is kept permanently open by a transcatheter device (InterAtrial Shunt Device, IASD; in the form of a tiny brace). Access is via the femoral artery under light sedation of the patient. The procedure usually takes about 1 hour. Studies show improvement in functional status and quality of life.Randomized comparative studies are awaited.

Heart Transplantation

Patients eligible for heart transplantation (abbreviated HTX; English heart transplantation) are selected patients with severe heart failure (AHA stage D) in whom symptom relief cannot be achieved despite medical and other surgical treatment. Furthermore, patients should be between ten and 65 years old and their life expectancy without transplantation should be short. A prerequisite for transplantation is also a high level of motivation on the part of the patient and a willingness to cooperate, especially during the period of rehabilitation after heart transplantation. However, the waiting time for a new organ in Germany is usually very long.