Peak Gradients and Left Ventricular Outflow Tract Area in Hypertrophic Obstructive Cardiomyopathy:A 3-Dimensional
Aidan Sharkey1, Usman Ahmed1, Adil Al-Karim Manji1
1Department of Anesthesia, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA.
Insights
Three-dimensional echocardiography accurately measures left ventricular outflow tract (LVOT) obstruction in hypertrophic obstructive cardiomyopathy (HOCM) patients. This technology aids surgeons in differentiating true obstruction from other gradient causes during septal myectomy.
Area of Science:
- Cardiology
- Echocardiography
- Cardiac Surgery
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) presents a significant challenge due to left ventricular outflow tract (LVOT) obstruction.
- Accurate intraoperative assessment of LVOT obstruction is crucial for successful septal myectomy.
- Differentiating true anatomic obstruction from dynamic or functional gradients is clinically important.
Purpose of the Study:
- To evaluate the relationship between 3D planimetry-determined LVOT area and Doppler-derived peak gradients in HOCM patients undergoing septal myectomy.
- To determine if 3D echocardiography can better differentiate true systolic anterior motion-related anatomic obstruction from other causes of elevated gradients.
Main Methods:
- Retrospective, single-center observational study of 36 HOCM patients undergoing septal myectomy.
- Real-time 3D echocardiography for pre-bypass LVOT planimetry.
- Dobutamine stress echocardiography before and after cardiopulmonary bypass to assess gradients and LVOT-mitral valve interaction.
Main Results:
- A strong preoperative correlation (r = -0.64) was found between LVOT area and peak gradient.
- Postoperatively, peak gradients significantly decreased, with a weaker correlation (r = -0.30) between LVOT area and gradients.
- 22% of patients had elevated gradients post-myectomy without demonstrable LVOT obstruction.
Conclusions:
- Intraoperative 3D echocardiography provides precise, real-time LVOT obstruction quantification in HOCM.
- This technology enhances intraoperative assessment during septal myectomy.
- 3D echocardiography may improve clinical decision-making by differentiating true LVOT obstruction from residual functional gradients.
Objectives:
To evaluate the relationship between intraoperative 3-dimensional (3D) planimetry-determined left ventricular outflow tract (LVOT) area and Doppler-derived peak gradients in patients with hypertrophic obstructive cardiomyopathy (HOCM) undergoing septal myectomy and to determine whether 3D echocardiography can better differentiate true systolic anterior motion-related anatomic obstruction from other causes of elevated gradients.
Design:
A retrospective, single-center, observational study.
Setting:
A single tertiary university hospital performing septal myectomy for HOCM.
Participants:
Thirty-six patients undergoing septal myectomy for symptomatic HOCM between February 2021 and December 2024.
Interventions:
Real-time 3D echocardiography was performed during pre-bypass procedural planning. Dobutamine stress echocardiography was conducted both before and after cardiopulmonary bypass to reproduce peak gradients and assess LVOT-mitral valve interaction. Septal myectomy was performed per standard surgical protocol.
Measurements And Main Results:
LVOT area was quantified using multiplanar reconstruction during stress echocardiography, and continuous-wave Doppler gradients were measured before and after myectomy. Preoperatively, stress augmentation resulted in a median 58.2% reduction in LVOT area at peak gradient levels previously associated with symptoms in the awake state. After myectomy, peak gradients decreased significantly (median, 11.5-24.0 mmHg; p < 0.001), with only a 16.9% reduction in LVOT area. A strong preoperative correlation was observed between LVOT area and peak gradient (r = -0.64, p < 0.001), which was weaker postoperatively (r = -0.30, p = 0.018). Postoperatively, 22% of patients showed elevated peak gradients without demonstrable LVOT obstruction.
Conclusions:
Intraoperative 3D echocardiography enables precise, real-time quantification of LVOT obstruction in HOCM and enhances intraoperative assessment during septal myectomy. It may improve clinical decision making in patients with high intracavitary gradients by differentiating true LVOT obstruction from residual functional gradients.
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