REVIEW OF RECENT ADVANCES & TECHNIQUES IN SURGICAL MANAGEMENT OF HEART FALIURE

Abstract

SUMMARY H eart failure is a complex clinical syndrome that can result from any structural or functional cardiac disorder that impairs the ability of the ventricle to fill with or eject blood. A syndrome in which the patients should have the following features: symptoms of HF, typically shortness of breath at rest or during exertion, and/or fatigue; signs of fluid retention such as pulmonary congestion or ankle swelling, and objective evidence of an abnormality of the structure or function of the heart at rest. The prevalence of heart failure in the community vary between countries, its estimated that in Europe where the population more than 900 million, there are at least 15 million patients with HF, so that HF is evident in 4% of the population. In Egypt the data is incomplete but its estimated at 10.9% of the population with the highest incidence of clinical HF occurring after 45 years of age. Heart failure has been broadly divided into two large groups according to the underlying pathology. The first group is that were the heart can’t maintain the normal cardiac output (ejection fraction) and is therefore termed Heart Failure with reduced Ejection Fraction (HFrEF). On the other hand in the second group the heart can maintain normal output but does so with elevated filling pressure that is why it is termed Heart Failure with preserved Ejection Fraction (HFpEF). Although the underlying causes for each type of heart failure are numerous. The common end point to all diseases that lead to heart failure is highly similar. This end point entails the activation of various neuro-hormonal systems in the body both to help restore normal cardiac function and to maintain adequate tissue perfusion. These mechanisms although useful at first, end up having adverse effects on the heart itself later in the course of disease; effects such as cardiac dilation and hypertrophy specifically are of the most harmful effects for the myocardium. When reviewing a patient with heart failure from the surgical point of view one should always keep in mind three questions that are; the stage/severity of heart failure, the reversibility of the causes and the cost-benefit to the patient. The progression of heart failure has been divided into 4 stages that complement the NYHA classification of symptoms, and have the added advantage of including asymptomatic patients. Each stage in this classification is assigned to certain treatment options starting from merely life style modifications in the earliest asymptomatic stage, to a large numbers of pharmacological choices, and finally in the later stages of heart failure interventional options are warranted which might range from implantation of pacemaker, Implantable cardiac defibrillator (ICD), cardiac resynchronization to major open heart surgeries. The role of cardiac surgeon in management of heart failure is fundamental as it can have a marked impact on the outcome and prognosis of patients from reversal of the causative effect that led to heart failure in the first place to surgeries that aim at improving the cardiac function and finally cardiac transplantation though not practiced in our country. An example of reversible cardiac causes that ends in heart failure are patients who suffer from coronary artery disease in which prolonged ischemia leads to stunning or hibernation of myocardium decreasing the myocardial contractility and hence decreasing the overall ejection fraction. In such patients were myocardial viability is proven, and despite very low ejection fraction many studies have shown that these patients may benefit greatly from coronary artery bypass graft surgery either alone or combined with other procedures in an attempt to revascularize the stunned or hibernating areas of the myocardium improving the ejection fraction postoperatively. Another example of reversible causes that lead to heart failure and can be managed surgically is valvular heart diseases. Regardless of the underlying etiology whether rheumatic or degenerative the common end point is a form of severe valvular pathology either stenosis or regurgitation that adversely affect the heart by forming a pressure or volume overload on the ventricles which eventually leads to failure. In cases of severe valve pathology specifically in the aortic or mitral valve replacement or repair surgeries can be performed aiming at reversing the impaired pathology and hence allowing a chance for the heart to recover. Some cardiac pathology might necessitate more advanced form of open heart surgeries, namely ventricular remodeling procedures. These are usually carried out in combination with other surgeries, commonly valve surgeries, as they are the most common causes that lead to ventricular dilation. Ventricular dilation can be either eccentric or concentric, but both lead to alteration of the normal anatomy of the heart leading to myocardial dysfunction. Many procedures have been designed to address this changed and distorted anatomy attempting to restore the normal cardiac morphology and restoring the heart to near normal anatomy hoping to restore normal cardiac function. In the past decade a new surgical option has been developing which shows very promising results for the future of heart failure is the development of mechanical devices that can assist the heart in performing its function. The idea for these devices was inspired by the cardio-pulmonary bypass machine that we use in surgery. The concept is similar yet different, in that devices don’t provide blood oxygenation; they rather assist only the circulation by means of a portable pump that can be implanted in patients thoracic cavity.

These Ventricular Assist Devices (VAD), have developed vastly in the past few years with the emergence of novel technology with the release of each generation of devices. The uses of VADs in heart failure patients are diverse; the range from being used as a short term support for the heart to recover after cardiogenic shock which is known as a “Bridge to recovery”, to being used as a temporary support till cardiac transplantation can be carried out known as a bridge to transplantation.