SURGERY FOR HEART FAILURE

Generally heart failure is considered as totally a medical problem as the risks with surgery are high. However in selected patients, who are resistant to medical therapy, cardiac surgery can make medical treatment easier, improving quality of life to the patient. And there are surgeries like heart transplantation which have been proven to increase the longevity of these patients. Basically surgeries in these patients are:

- Those that identify and remove the primary insult that resulted in heart failure
- those that try to surgically reverse remodel the ventricle,
- using assist devices
- heart transplantation and
- Sometimes combination of the procedures.
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Surgeries for removing the primary insult:

These include operations for coronary artery disease and valve diseases that resulted in heart failure and significant left ventricular dysfunction.

Coronary artery bypass surgery: Myocardial ischemia is probably the most important cause of heart failure and is associated with a 30% - 50% annual mortality. However reduced ventricular function may be reversible with ischemia. Restoration of function with correction of ischemia may take some time, on occasion, months. Identifying the presence of such hibernation is probably best achieved with labelled (F18 deoxyglucose uptake) positron emission tomographic (PET) metabolic studies. If it shows viable myocardium >20% of left ventricular mass, evidence is stronger. Viable myocardium can also be demonstrated by dobuatmine stressed echo and its characteristic bi-phasic response to increasing levels of inotrope. There is an initial improvement in contractility followed by a fall off in function as dobutamine levels reach values of 25 – 40g/Kg/min. Magnetic Resonance imaging (MRI) is showing promise too by revealing scar or viable muscle. Sometimes even 2D echo may give some suggestion of viability through the thickness of myocardium and subendocardial thickening. However one has to consider the clinical condition, evidence for significant viable myocardium and the high risks involved in these patients before advising surgery. Sometimes bypass surgery may have to be combined with mitral valve repair surgery or with left ventricular remodelling surgery.

Valve surgery: In India rheumatic heart disease still contributes to significant proportion of heart diseases. Today advances in surgery allow most valve disease patients with left ventricular dysfunction to be operated successfully although prognosis is still reduced in such patients. However surgery is likely to reduce number of hospital admissions with heart failure and improve their quality of life. Aortic stenosis patients with low gradient and low ejection fraction without inotropic reserve and mitral incompetence patients with ejection fraction of <30% in whom mitral subvalvar apparatus cannot be preserved constitute the small group in whom valve replacement surgery should probably not be performed.


Surgical procedures to improve cardiac output by reducing left ventricular size (“La Place surgery”):

Many modalities are being tried in the world today that aims at reducing an enlarged ventricular volume and reversing the forces that are driving further ventricular remodelling. Some of these are
(i) The Myo-splint.
ii) The CorCap® or Acorn device
iii) Left ventricular aneurysmectomy.
(iv) Mitral valve repair for secondary regurgitation.

One of the more accepted modalities is left ventricular aneurysmectomy when there is a left ventricular aneurysm causing heart failure. Dyskinetic segment of ventricle is removed reducing ventricular diameter and so reducing ventricular wall tension. However the segment removed here is scar and not ventricular muscle. The aim is to restore a more “normal” ventricular geometry increasing the efficiency of ventricular contraction..




Surgical strategies to re-power the failing heart:
These include surgeries like implanting ventricular assist devices and heart transplantation.

Ventricular assist devices (VAD): The intention here is to off-load the failing heart. This is achieved by the unloading of blood from the ventricle and delivering into the arterial tree (pulmonary for right ventricular assist or RVAD and systemic for left or LVAD). Both ventricles may be supported simultaneously with BIVADs. Total excision of a failing heart is occasionally undertaken followed by replacement with an artificial heart (Cardiowest, Abiocor).
Generally a potential VAD candidate presents with severe, refractory heart failure with deterioration despite intensive medical therapy. A VAD is selected and may be temporary or long–term. Some are designed for per cutaneous insertion into the systemic arterial tree lying across the aortic valve (Impella). More usually VADs are inserted via a sternotomy. Patients are often mortally ill with multi-system dysfunction. Bleeding, control of vascular resistance and multi-organ failure are early problems soon replaced by risks of infection and thrombo-embolism. Mostly these are used as bridge to transplantation in individuals who are on inotropes with haemodynamic instability and waiting for a suitable heart donor.. Interestingly some patients (often those with a short but aggressive history of failure or myocarditis) recover so that the VAD can be removed and heart transplantation avoided.

Heart Transplantation: Despite many advances in the management of chronic heart failure, many patients continue to progress to advanced end-stage heart failure. For those that are suitable, heart transplantation is the only proven therapy to offer improved survival and quality of life. Current survival for heart transplantation approaches 80-90% survival and 50-60% at 10 years. In addition to improving the longevity of life, it is associated with a marked increase in quality of life despite the need to take life long immunosuppressive medication and follow-up. In India now there are centres working to develop this transplantation facility.