Surgical and mechanical support of the failing heart

Abstract

The surgical treatment of acute heart failure is limited to cases of pressure or volume overload. Acute valvular regurgitation due to active endocarditis or to prosthetic dysfunction is a classic example of failure which can be cured by restoring valvular competence. Acute pressure load is mostly caused by prosthetic dysfunction or pulmonary embolism; therapy is aimed at removal of the causative agent. Coronary heart disease can cause heart failure by volume overload: acute mitral incompetence or ventricular septal defect lend themselves to surgical correction. In the surgical treatment of acute heart failure maximal attention is devoted to optimal timing of surgery, anesthetic management and postoperative care. Careful attention to the function of the right and left ventricle and combination of catecholamines, afterload reducing agents and volume loading together with respirator support have considerably improved the surgical results. Acute pump failure due to coronary insufficiency and infarction is less amenable to surgical treatment, with rare exceptions of emergencies during coronary angiography and percutaneous dilatation. The intra-aortic balloon pump is the only method of mechanical circulatory assistance which has reached widespread clinical acceptance. The best results are achieved in conjunction with surgery: either as cardiac support in inherently reversible postoperative heart failure or as the means of circulatory stabilization prior to surgery. Ventricular assist devices are still in the experimental stage: their use has been sharply curtailed by the virtual disappearance of the postoperative low output syndrome. In selected cases of end-stage cardiomyopathy cardiac transplantation is nowadays performed with acceptable survival (70% at one year after surgery). Both orthotopic and heterotopic transplantation (transplanted heart in parallel with the natural one) give comparable results, but the procedure is still very restricted due to the lack of donors, multiple contraindications and lack of suitable heart preservation techniques.