The concept of Percutaneous Ventricular Restoration Therapy was presented for the first time at EuroPCR 2012. On Friday 18th May, Marco Costa from University Hospitals, Case Western Reserve University, US, revealed the 2-year outcome data from a first-in-man trial using the Parachute Partitioning Device in patients with heart failure.
Ischemic congestive heart failure is a global clinical problem without a therapeutic solution. The clinical and health economic burden is enormous with a 50% patient mortality at five years and a 50% hospital readmission rate within six months.
This condition frequently follows an infarct to the left anterior descending (LAD) coronary artery, causing cell death in the apex of the left ventricle. Progressive changes in left ventricular structure, geometry and contraction characteristics occur, and a dilated, non-contracting (akinetic) or abnormally contracting (dyskinetic) left ventricular apex develops. Critically, increased intraventricular pressures and increased total volume of the heart occur, and the normal 'torsional' contraction mechanism of the left ventricle (LV), which ejects blood from the apex to the outflow tract, is lost.
Recent studies have shown that reduction in cardiac volume is the key to improving outcomes in cardiac failure. The rationale of a new therapy is therefore to reduce the volume of the heart and restore original geometry.
A new catheter-based implantable ventricular partitioning device (the 'Parachute') has been developed to treat patients with LV dysfunction and anteroapical regional wall motion abnormalities after a myocardial infarction (MI). Such a device falls into a new therapeutic category of percutanous medical devices that address ventricular remodelling in heart failure patients - Percutaneous Ventricular Restoration Therapy (PVRT).
The implant comprises Nitinol struts with anchors, an expanded polytetrafluoroethylene (ePTFE) membrane and radiopaque polymer foot, delivered via a dedicated delivery system which centralises the device in the LV without traumatising the aortic wall. Preclinical studies in sheep have shown that the device reduces diastolic and systolic volumes and restores the conical apical ventricular shape and torsional ventricular contraction. The resulting synchronised contraction 'excludes' the abnormal apex, effectively partitioning the left ventricle. Cardiac efficiency is improved and a good healing response is seen, characterised by endothelialisation on both sides of the ePTFE membrane.
The first-in-human clinical trials commenced in 2005 and involved 19 patients from Europe and 20 from the US. Of these, 31 were discharged with a Parachute, and data were presented from 2-year follow-up of these patients. The target population is those patients who are NYHA Class II-IV, have an ejection fraction ≥ 15% and ≤ 40%, are post LAD MI with no revascularisation option, and have a dilated apical region with an akinetic or dyskinetic wall motion abnormality.
Consistent improvement in LV end diastolic volume (EDV) and end systolic volume (ESV) indices and preservation of cardiac output was achieved; i.e. maintenance of cardiac output under a much less 'stressed' condition. A greater predicted probability of achieving significantly decreased mortality was achieved. These haemodynamic findings were reflected in functional outcomes. At 12 months there were mean improvements in NYHA class (2.6 to 1.9), MWHF quality of life score (39 to 27) and 6-minute walking distance (352 to 389). Very low rates of cardiac death were maintained over two years, and worsening HF and death (the primary endpoint to be used in a planned pivotal trial) at 2-year follow-up was 29.5% in the treated population.
In perspective, these data (albeit unsupported by a control group) compare extremely favourably with data from other trials evaluating outcomes using optimal medical treatment with ICD and/or CRT. The 12-month worsening HF and death outcome achieved was below 17% in this trial compared with over 25% for any of the other trials.
The procedure appears very safe, and better results may be achieved as the technology is improved with increasing experience. The FDA has approved an open label, randomised, controlled trial in 50 US and 15 European sites, due to start this summer.
Marco Costa is cautiously enthusiastic. "We have come a long way with developing complex technology to treat complex problems. For the first time we have a simple technology which is easy to deliver and has minimal procedural risk, but can actually tackle a very significant disease which has a high morbidity and mortality. This procedure will be done by the average interventional cardiologist in conjunction with the heart failure team and does not need to be done in selected specialist centres."
Hüseyin Ince, from the University of Rostock, Germany, has performed the procedure in eight patients to date, achieving similarly encouraging initial outcomes. He said: "For the right patient it is the best innovation in heart failure we have had in the past 10 years."
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