Case Report: Minimally Invasive Therapy by Transcatheter Aortic Valve Replacement and Percutaneous Intramyocardial Septal Radiofrequency Ablation for a Patient With Aortic Stenosis Combined With Hypertrophic Obstructive Cardiomyopathy: Two-Year Follow-Up Results

Radiofrequency ablation in patients with obstructive hypertrophic cardiomyopathy: A systematic review and meta-analysis

Study objective

Hypertrophic cardiomyopathy (HCM) is a genetic disease that can cause left ventricular outflow tract (LVOT) obstruction. This study analyzed the efficacy of radiofrequency ablation (RA) in improving clinical and hemodynamic factors in patients receiving obstructive HCM refractory treatment. This evaluation was necessary because of the small number of studies on the effectiveness of this technique for obstructive HCM in the existing literature.

Design

We used the PubMed, Embase, and Science Direct databases to identify randomized clinical trials and observational studies addressing the clinical and hemodynamic outcomes before and after RA in patients with HCM.

Participants

We selected six articles published between 2011 and 2022, comprising 304 patients (mean age: 45 years).

Interventions

We performed a bias assessment using the ROBINS I tool, and meta-analysis processing was performed using the STATA program (v.16.0).

Results

The left ventricular outflow tract (LVOT) gradient at rest and with stimulation decreased by 58.78 mmHg (p = 0.001) and 70.38 mmHg (total effect Z = 21.62; p < 0.0001), respectively. Additionally, the New York Heart Association (NYHA) functional class decreased by 0.43 (p = 0.001), indicating symptomatic and hemodynamic improvements. Furthermore, we observed a significant reduction in septal thickness (by 4 mm; p = 0.001).

Conclusions

RA improved the NYHA functional class and LVOT gradient at rest and with stimulation and reduced septal thickness. These results suggest that RA is effective in patients refractory to pharmacological therapy and unsuitable for alcohol septal ablation or myectomy. However, more studies, including randomized clinical trials, should be conducted to define the role of RA in interventional therapies.

First-in-man application of Liwen RF™ ablation system in the treatment of drug-resistant hypertrophic obstructive cardiomyopathy

OBJECTIVES

This study sought to evaluate the clinical applicability of the Liwen Liu RF™ ablation system for percutaneous intramyocardial septal radiofrequency ablation (PIMSRA).

BACKGROUND

Data on new cardiac radiofrequency ablation devices for the treatment of hypertrophic obstructive cardiomyopathy (HOCM) are limited.

MATERIALS AND METHODS

From July 2019 to July 2020, a total of 68 patients with drug-resistant HOCM, who underwent PIMSRA with the Liwen RF™ ablation system, which has an ablation electrode of stepless adjustable length, were prospectively enrolled. Safety endpoints included, amongst others, the occurrence of pericardial effusion and/or hemorrhage, cardiac arrhythmias, device failure and procedural death. The reduction in left ventricular outflow tract (LVOT) gradients at 12 months follow-up were used as a surrogate marker for device efficacy.

RESULTS

All procedures were technically successful. The total energy output time of the system was 75.8 (IQR: 30.0) min, and the average power was 43.61 ± 13.34 watts. No ablation system error occurred. The incidence of pericardial effusion or hemorrhage, transient arrhythmia and resuscitation was 8.8, 39.7, and 1.5% during procedure, respectively. None of the patients died. During 30-day follow-up, there were no complications with the exception of a pericardial effusion in one patient (1.5%). No further complications were reported after 30 days. The patients' resting [baseline: 75 (IQR: 48) vs. 12-months: 12 (IQR: 19) mmHg, p < 0.001] and provoked [baseline: 122 (IQR: 53) vs. 12-months: 41 (IQR: 59) mmHg, p < 0.001] LVOT gradients decreased significantly during follow-up.

CONCLUSION

In this study, we demonstrate the safety and feasibility of the Liwen RF™ ablation system to treat HOCM. The system allows for significant and sustainable LVOT gradient reduction during 12-months of follow-up. Hence, the Liwen RF™ ablation system is a promising new device that has the potential to become an alternative to existing septal reduction concepts in HOCM patients.