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Hypertrophic Obstructive Cardiomyopathy: Discrepancy Between Hemodynamic Measurements in the Cardiac Laboratory and
Juliano Lentz Carvalho1, Elena Ashikhmina2, Martin D Abel3
1Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN.
Insights
Hemodynamic values for left ventricular outflow tract (LVOT) obstruction in hypertrophic obstructive cardiomyopathy patients show discrepancies between preoperative and intraoperative measurements. These differences, while common, typically do not alter patient care decisions.
Area of Science:
- Cardiology
- Cardiovascular Surgery
- Medical Imaging
Background:
- Hypertrophic obstructive cardiomyopathy (HOCM) frequently presents with discrepancies in hemodynamic measurements of left ventricular outflow tract (LVOT) obstruction between preoperative assessments and intraoperative findings.
- Accurate interpretation of these hemodynamic differences is crucial for effective surgical planning and patient management.
Purpose of the Study:
- To investigate the extent of discrepancies in hemodynamic variables for patients undergoing septal myectomy for HOCM.
- To compare preoperative and intraoperative hemodynamic measurements, including LVOT gradients and pulmonary artery systolic pressures.
Main Methods:
- A retrospective study was conducted at a single academic medical center.
- Data from 173 patients undergoing septal myectomy were reviewed.
- Hemodynamic variables were compared between preoperative evaluations (transthoracic echocardiography and estimated pulmonary artery systolic pressure) and intraoperative measurements (direct needle-resting LVOT gradient, transesophageal echocardiography, and pulmonary artery catheter).
Main Results:
- No significant difference was found in resting peak LVOT gradients between preoperative transthoracic echocardiography and intraoperative transesophageal echocardiography (46 mmHg vs. 36 mmHg, p=0.231).
- Preoperative transthoracic echocardiography gradients were higher than direct needle-resting LVOT gradients measured before myectomy (49 mmHg vs. 32 mmHg, p=0.0022).
- Intraoperative pulmonary artery systolic pressures were higher than preoperative estimates (39 mmHg vs. 34 mmHg, p<0.0001).
- The incidence of moderate/severe mitral regurgitation was higher intraoperatively.
Conclusions:
- Discrepancies between preoperative and intraoperative hemodynamic measurements in HOCM patients are common.
- These hemodynamic variations are likely influenced by factors such as fasting, anesthesia, fluid shifts, ventilation, and measurement techniques.
- Observed discrepancies generally do not necessitate changes in planned patient care.
Objectives:
It is not uncommon to observe some discrepancy in hemodynamic values characterizing left ventricular outflow tract (LVOT) obstruction preoperatively and in the operating room in patients with hypertrophic obstructive cardiomyopathy. Interpretation of this discrepancy can be challenging. To clarify the extent of the discrepancy, the authors compared hemodynamic variables in patients undergoing septal myectomy at the time of preoperative and intraoperative evaluation.
Design:
Retrospective study.
Setting:
Single academic medical center.
Interventions:
Medical records review, study group-173 patients.
Measurements And Main Results:
While there was no statistically significant difference in resting peak LVOT gradients by preoperative transthoracic echocardiography (TTE) compared to intraoperative transesophageal echocardiography (46 mmHg [19-87 mmHg] v 36 mmHg [16-71 mmHg], p = 0.231), the former were higher compared to direct needle-resting LVOT gradient measurements before myectomy (49 mmHg [19-88 mmHg] v 32 mmHg [14-67 mmHg], p = 0.0022). The prevalence of systolic anterior motion was high (94.6% v 91.6%, P = 1.000) both on pre- and intraoperative evaluation. The incidence of moderate/severe mitral was higher intraoperatively (p < 0.0001). Pulmonary artery systolic pressures measured by pulmonary artery catheter provided higher values compared to preoperative TTE estimate (39 mmHg [34-45 mmHg] v 34 mmHg [28-41 mmHg], p < 0.0001).
Conclusions:
Discrepancy between hemodynamic measurements in the cardiac laboratory and operating room is common and generally should not affect planned patients' care. These changes in hemodynamics might be explained by preoperative fasting, anesthetic agents, volume shifts while supine, and positive-pressure ventilation, as well as the difference in measurement techniques.
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