Introduction
At present, over 15 million people are living with heart failure in Europe. Heart failure is responsible in most westernized economies for 1-2% of all healthcare expenditures and is the leading cause of hospitalization in people over the age of 65. The prognosis for HF patients has remained alarmingly poor over the last twenty years. Despite some notable improvements in survival rates, approximately 1 in 3 patients admitted to a hospital with HF still die within one year. This places a huge financial burden on the health care system and signals the typical downward spiral of the course of this disease. Due to this fact, there has been a significant paradigm shift in the focus of cardiac treatment worldwide in last two decades.
It has been common knowledge since the pivotal report by White et al. that left ventricular (LV) chamber size is the single most important metric in determining survival post myocardial infarction (MI). Ischemic cardiomyopathy is a disease process wherein the patient develops HF due to scar formation and subsequent LV enlargement. Ischemic cardiomyopathy is the largest cause of HF, comprising approximately two-thirds of all the 22 million HF patients worldwide. Analysis of the 10-year survival of these patients based on LV size demonstrates the rapid divergence in death rate in the initial several years. Hence, developing a safe and effective approach for volume reduction in this most vulnerable patient segment is the significant challenge in modern cardiac care.
Ischemic cardiomyopathy is frequently associated with LV scarring where viable heart tissue has been damaged and is replaced by fibrotic scar, which results in left ventricular dysfunction. The loss in left ventricular function most often results in angina, significant dyspnoea, ventricular arrhythmias, and an increased risk of thromboembolism and death.
Surgical treatment is an option in advanced HF. Patients with significantly enlarged LV end-systolic and end-diastolic volume indices (LVESVI and LVEDVI) appear to benefit most from surgical intervention. Relative contraindications to surgery include excessive anaesthetic risk, impaired function of residual myocardium, severely diminished cardiac index, and lack of a discrete scar with indistinct margins. Left ventricular surgical treatment usually requires a median sternotomy, cardiopulmonary bypass, and left ventriculotomy on either a beating or arrested heart. Adoption of the surgical technique for correction of this condition has been limited by both the invasiveness of the procedure and potential for significant subsequent perioperative morbidity and mortality. BioVentrix™ has developed the Revivent TC™ System to provide devices for the treatment of a left ventricular scar, utilizing a less invasive, beating heart approach.
Less Invasive Ventricular Enhancement (LIVE) procedure with Revivent TC™ reshapes and resizes LV without sternotomy or extracorporeal circulation through direct plication of the scarred myocardium. The procedure consists in the implantation of a series of internal (right ventricular septum) and external titanium microanchors (5 mm × 25 mm) which are brought together through a poly-ether-ether-ketone (PEEK) tether (1.7 mm × 1.0 mm) to approximate LV free wall and the anterior septum, consequently excluding the scarred myocardium. Septal RV anchors are deployed by a transcatheter technique, through a venous access on the neck – right internal jugular vein.
First-in-human LIVE procedures were performed in September 2013. Since the device obtained CE mark approval in June 2016, the multicentric observational BioVentrix™ Registry Assessment of Ventricular Enhancement for the Revivent TC™ system (BRAVE-TC) trial has been ongoing in Europe (1).
In total, 230 cases have been performed with an overall mortality of 18 (7.8%). 12 cases of mortality occurred during the CE mark trial and 4 prior to changing the procedure to apical snaring (described below).
One-year results of a multicentric study were recently published by Klein et al. (2), including 86 patients treated with Revivent TC™ system has registered a significant improvement in LV ejection fraction (29 ± 8% vs 34 ± 9%, p<0.005) and an important reduction of LV volumes - LV end-systolic and end-diastolic volume indexes (LVESVi and LVEDVi) both decreased: 74 ± 28 mL/m2 vs 54 ± 23 mL/m2, p<0.001 and 106 ± 33 mL/m2 vs 80±26mL/m2, respectively, p<0.0001. Mortality was 4.5% (4 patients) and 12-months survival was 90.6%. There was also a documented clinical improvement of the treated patients. This is the largest series of patients submitted to LIVE therapy published so far.
In another series of 26 patients submitted to the LIVE™ therapy (3), meaningful LV reduction was achieved - LVSEVi went from 84.8 ± 25.7 to 65.6 ± 24.4 ml/m2 and LVEDVi went from 107.8 ± 33.2 to 90.5 ± 31.8 ml/m2, both p<0.001 (Figure 1 ). Additionally, ejection fraction improvement was observed by CMR: 28.9 ± 8.3% vs 38.6 ± 10.5%, p<0.001. There was one mortality case reported. Lastly, also the 6-minute walk test was significantly longer (368.8 ± 40.0 to 461.5 ± 61.2 m, p <0.001), endorsing clinical benefit with the technique.
Between July 2018 and January 2020, 47 patients (84.4% men; mean age 61 ± 12.5 years) were submitted to the LIVE procedure in 16 Institutions in Europe, North America and Asia. Procedural success was 100%. There was no intra-hospital mortality. There was no case of ventricular septal defect, right ventricular perforation or sternotomy conversion. New onset tricuspid valve regurgitation was observed in one patient. In the mean follow-up period of 9.8 months, NYHA class improved a median of 1 grade and there was no late mortality.
We present this approach here, describing it step-by-step.