Transseptal and transmitral Parachute® implantation in conjunction with "MitraClipping"

Comparative analysis of femtosecond, picosecond, and nanosecond laser techniques for transseptal puncture: An in vitro study with pathological correlation

BACKGROUND

Advanced precision laser technologies for transseptal puncture are still under exploration. Femtosecond lasers, renowned for their high precision and minimal collateral damage, exhibit significant potential in transseptal puncture applications.

OBJECTIVE

This study investigated the feasibility, effectiveness and pathological effects of femtosecond, picosecond, and nanosecond lasers for transseptal puncture in vitro.

METHODS

Three different pulsed laser systems (femtosecond, picosecond, and nanosecond) were utilized for atrial septal puncture in fresh porcine hearts. The femtosecond laser operated at 1064 nm wavelength with 179 fs pulse width and 500 kHz repetition rate; the picosecond laser at 1962 nm with 52 ps pulse width and 60 MHz repetition rate; and the nanosecond laser at 1064 nm with 70 ns pulse width and 60 kHz repetition rate. With a focused spot size of approximately 100 μm, the power density ranged from 25.50 to 51.00 kW/cm2 (corresponding to energy densities of 0.05-0.10 J/cm2 for femtosecond, 424.40-848.80 μJ/cm2 for picosecond, and 0.42-0.85 J/cm2 for nanosecond lasers). Scanning diameters varied from 0.50 to 3.00 mm at a constant speed of 1 mm/s. Measurements of puncture diameter and thermal damage were taken using a digital optical microscope, with pathological examination evaluating tissue structure and injury extent. Multiple linear regression models were used to evaluate the effects of laser types, power, and scanning diameter on puncture outcomes. P < 0.05 was considered statistically significant.

RESULTS

Using a focused spot size of 100 μm at power densities of 25.50-51.00 kW/cm2 (2.0-4.0 W), the femtosecond laser (500 kHz, 0.05-0.10 J/cm2) and picosecond laser (60 MHz, 424.40-848.80 μJ/cm2) achieved complete penetration across 0.50-3.00 mm scanning diameters, with puncture diameters of 0.51-3.02 mm and 0.51-3.01 mm respectively. The nanosecond laser (60 kHz, 0.42-0.85 J/cm2) penetrated only at 0.50 mm scanning diameter and partially at 1.00 mm (3 W-4 W), with significantly smaller diameters (P < 0.001). Multiple regression showed scanning diameter primarily determined puncture size (β = 0.992, P < 0.001), while both power (β = 1.798, P = 0.002) and scanning diameter (β = 2.604, P < 0.001) affected thermal damage, with nanosecond (β = 6.515, P = 0.017) and picosecond lasers (β = 5.595, P = 0.039) showing greater thermal effects than femtosecond laser. Histologically, thermal damage progressed from minimal carbonization at 2 W to moderate-severe eosinophilic degeneration at 4 W… CONCLUSIONS: Transseptal puncture using laser systems demonstrated feasibility, particularly with femtosecond laser showing favorable outcomes in precision and thermal control under specified parameters, exhibit significant clinical potential. Further studies are needed to investigate the underlying mechanisms.

KEY MESSAGES

What is already known about this subject? Femtosecond lasers, characterized by their high peak power and minimal thermal damage, are expected to have potential clinical applications in transseptal puncture techniques. What does this study add? The effects of femtosecond, picosecond, and nanosecond lasers on ex vivo porcine atrial septum puncture were studied at varying power levels and puncture diameters. The results showed that femtosecond lasers had superior puncture capabilities compared to nanosecond lasers, with significantly higher thermal damage observed in the nanosecond laser. How might this impact on clinical practice? Ex vivo experiments with advanced lasers, particularly femtosecond lasers, have shown promising clinical feasibility. We will plan to pursue further research based on current findings.

Heart Failure Interventions Targeting Impaired Left Ventricles in Structural Heart Disease

PURPOSE OF REVIEW

Interventional techniques have been developed for a wide spectrum of mechanisms of heart failure (HF), especially in valvular heart disease and cardiomyopathies (ischaemic cardiomyopathy and hypertrophic cardiomyopathy). In this article, we review recent reports on catheter interventions to treat patients with HF.

RECENT FINDINGS

Direct modification using the Parachute device and the REVIVENT-TC device for patients with impaired left ventricle with large infarct scars improves geometry and haemodynamic efficiency, resulting in a reduction of HF symptoms. Interatrial shunt therapy improves symptoms and quality of life in HF patients. Uniquely, left ventricular outflow tract obstruction has also been targeted in patients with transcatheter mitral valve implantation. For advanced stage HF patients with prohibitively high surgical risk, emerging transcatheter interventions make it possible to modify life-limiting symptoms. Further results on HF interventions are expected from ongoing clinical trials.

Left ventricular partitioning in systolic heart failure subjects: addressing a mechanistic void with current therapies

ICD patients with narrow QRS, CRT non-responders, and functional MR patients all have one mechanistic failure mode that is left untreated - the scar left behind following an MI. ICDs, CRTs, and MitraClip implantation are all well-proven therapies, but the Parachute device may address the mechanistic void that remains after each of these therapies has been used and may further improve patients' outcomes. A pooled analysis of 134 subjects was conducted using the first three clinical trials which included subjects with symptomatic ischaemic HF with LV wall motion abnormalities secondary to MI, and an LV ejection fraction less than 40%. The two-year cumulative mortality rate was 12.9%, with 8.7% in the first year and an increment of 4.2% in the second, which is a 53% reduction as compared to the first year. There is a significant proportion of patients with ischaemic heart failure being excluded from cardiac rhythm management (CRT, etc.), leaving a large treatment gap until mechanical support devices (LVAD) or heart transplantation in progressive heart failure are indicated. Along with other heart failure devices, Parachute may be a useful treatment modality, addressing a mechanistic void in the treatment of this disease. Current data support improvements in haemodynamics, functional capacity, six-minute walk distance, quality of life and a promising decline in mortality two years after Parachute implantation.