Cardiac Shockwave Therapy Plus CABG for Ischemic HF

Quick Takes

  • The current study is the first randomized, sham-controlled trial to evaluate the effects of direct cardiac shockwave therapy (SWT) with CABG among patients with reduced LV function undergoing surgical revascularization. After revascularization, while still on cardiopulmonary bypass, shockwaves were applied in direct contact to ischemic myocardium, as identified by preop cardiac MRI.
  • Direct SWT plus CABG was associated with significant improvement in the LVEF group (Δ from baseline to 360 days: SWT 11.3%, SD 8.8; sham 6.3%, SD 7.4, p = 0.0146) and functional status at 1 year compared to sham therapy plus CABG.

Study Questions:

What is the safety and efficacy of direct cardiac shockwave therapy (SWT) among patients with ischemic cardiomyopathy undergoing coronary artery bypass graft surgery (CABG)?

Methods:

In this single-blind, parallel-group, sham-controlled trial (cardiac shockwave therapy for ischemic heart failure, CAST-HF; NCT03859466), patients with left ventricular ejection fraction (LVEF) ≤40% requiring surgical revascularization were enrolled. Patients were randomly assigned to undergo direct cardiac SWT or sham treatment in addition to CABG. The primary efficacy endpoint was the improvement in LVEF measured by cardiac magnetic resonance imaging (MRI) from baseline to 360 days.

Results:

Overall, 63 patients were randomized, out of which 30 patients of the SWT group and 28 patients of the sham group attained 1-year follow-up of the primary endpoint. Greater improvement in LVEF was observed in the SWT group (Δ from baseline to 360 days: SWT 11.3%, SD 8.8; sham 6.3%, standard deviation [SD] 7.4, p = 0.0146). Secondary endpoints included the 6-minute walking test, where patients randomized in the SWT group showed a greater Δ from baseline to 360 days (127.5 m, SD 110.6) than patients in the sham group (43.6 m, SD 172.1) (p = 0.028) and Minnesota Living With Heart Failure Questionnaire score on day 360, which was 11.0 points (SD 19.1) for the SWT group and 17.3 points (SD 15.1) for the sham group (p = 0.15). Two patients in the treatment group died for non–device-related reasons.

Conclusions:

The CAST-HF trial indicates that direct cardiac SWT, in addition to CABG, improves LVEF and physical capacity in patients with ischemic heart failure.

Perspective:

Cardiac SWT proposes to induce regenerative effects (angiogenesis) in ischemic myocardium via the principle of mechanotransduction (physical stimulus translating into a specific biologic signal). The current study is the first randomized, sham-controlled trial to evaluate the effects of direct cardiac SWT with CABG among patients with reduced LV function undergoing surgical revascularization. After revascularization, while still on cardiopulmonary bypass, shockwaves were applied in direct contact to ischemic myocardium, as identified by preoperative cardiac MRI. Three hundred impulses per coronary supply territory were applied at an energy flux density of 0.38 mJ/mm2 and a frequency of 3 Hz.

Direct SWT plus CABG was associated with significant improvement in the LVEF group (Δ from baseline to 360 days: SWT 11.3%, SD 8.8; sham 6.3%, SD 7.4, p = 0.0146) and functional status at 1 year compared to sham therapy plus CABG. There were no safety concerns reported. If findings are confirmed in a larger trial, SWT could be an important breakthrough therapy to improve outcomes among a challenging group of patients with ischemic cardiomyopathy.

Clinical Topics: Cardiac Surgery, Cardiovascular Care Team, Heart Failure and Cardiomyopathies, Invasive Cardiovascular Angiography and Intervention, Cardiac Surgery and Heart Failure

Keywords: Cardiomyopathies, Coronary Artery Bypass, Extracorporeal Shockwave Therapy


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