Surgical ventricular restoration
Surgical ventricular restoration (SVR) involves exclusion of scar on the ventricular wall from previous myocardial infarction.
The aims of SVR are to:
- normalise ventricular geometry
- improve myocardial perfusion
- reduce left ventricular work
- improve left ventricular contraction.
The early procedures were similar to partial left ventriculectomy for aneurysm, while the contemporary SVR involves resection of the non-functional myocardium before placement of an endoventricular Dacron patch to exclude the scar (figures 11a–d). It is usually done during CABG for patients with ischaemic cardiomyopathy and anterior wall akinesia or severe dyskinesia. It adds about 20 minutes to the procedure time without increasing operative risk.
In non-randomised studies, SVR improves LVEF and other haemodynamic variables. However, hypothesis 2 of the STICH trial compared outcomes of patients randomised to CABG plus SVR to CABG alone and found no significant difference in the composite endpoint of all-cause mortality or cardiovascular hospitalisation.
Percutaneous ventricular restoration has also been investigated: the Parachute device, a percutaneously delivered device that partitions the left ventricle as a means of ventricular restoration, appears safe and feasible in patients with heart failure and left ventricular dilatation.16 However, a phase III trial was terminated in June 2017.17
There may yet be sub-groups who do benefit from surgical or percutaneous ventricular restoration and, similar to the story with revascularisation, this book is not yet closed.
An important cause of the heart failure syndrome is valvular heart disease. Every patient presenting with heart failure should be assessed for valvular disease: aortic stenosis is a particular common cause. Patients should be offered aortic valve replacement as a potentially curative procedure. In many patients, however, by the time they present, they may be too frail for open surgical valve replacement. In these cases, transcatheter aortic valve implant (TAVI) should be considered as being a lower risk alternative. TAVI is certainly superior to medical therapy in inoperable patients, and is increasingly being shown in trials to be as effective as surgical valve replacement in lower risk patients.
A more difficult problem is that of mitral valve surgery. Functional mitral regurgitation is very common in heart failure as a consequence of valve ring dilation together with tethering of the posterior leaflet of the valve. There are no good randomised trials of mitral valve surgery in this clinical situation, but data from registries suggest that there is little to be gained from a high risk procedure. Whether there is anything to be gained from mitral valve repair using percutaneous strategies (such as the MitraClip® or percutaneous valve prostheses) is not clear.
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