Echocardiographic and Clinical Outcomes of Concomitant Secondary Chordal Cutting to Surgical Myectomy in Hypertrophic Obstructive Cardiomyopathy: A Systematic Review and Meta-analysis

In patients who underwent surgical myectomy for hypertrophic obstructive cardiomyopathy (HOCM), additional mitral valve repair may offer additional benefits in terms of further reducing left ventricular outflow tract (LVOT) gradients, systolic anterior motion (SAM), and mitral regurgitation (MR). We performed a systematic review of the literature to evaluate the evidence of surgical myectomy with additional secondary chordal cutting in patients with HOCM. A systematic literature search in MEDLINE and EMBASE was performed until April 2024. The primary outcome studied was postoperative echocardiographic LVOT gradient. A random effects meta-analysis of means was performed for the primary outcome. The secondary outcomes studied were postoperative residual MR grade, 30-day new permanent pacemaker implantation, and in-hospital mortality. From 1,911 unique publications, a total of 6 articles fulfilled the inclusion criteria and comprised 471 patients with a pooled mean preoperative resting LVOT gradient of 84 mm Hg (95% confidence interval [CI]: 76-91). The postoperative pooled mean LVOT gradient was 11 mm Hg (95% CI: 10-12) with a low heterogeneity (I 2 = 44%). The residual LVOT gradient exceeding 30 mm Hg was present in nine (1%) patients. MR grade 3 or 4 at hospital discharge was present in seven (1%) patients. The 30-day new permanent pacemaker implantation rate was 7% and the in-hospital mortality was 0.4%. This systematic review and meta-analysis demonstrate that combining surgical myectomy with secondary chordal cutting can be performed safely and effectively eliminate LVOT obstruction in HOCM patients. Further studies are needed to determine the additive effectiveness of additional secondary chordal cuttings.