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Variability of left ventricular outflow tract gradient during cardiac catheterization in patients with hypertrophic
Jeffrey B Geske1, Paul Sorajja, Steve R Ommen
1Divisions of Cardiovascular Diseases and Internal Medicine, Mayo Clinic College of Medicine, Rochester, Minnesota, USA.
Insights
Left ventricular outflow tract (LVOT) gradients in hypertrophic cardiomyopathy (HCM) fluctuate significantly during cardiac catheterization. This variability can lead to misclassification of obstruction severity in half of patients.
Area of Science:
- Cardiology
- Cardiovascular Physiology
Background:
- Hypertrophic cardiomyopathy (HCM) management relies on assessing left ventricular outflow tract (LVOT) obstruction.
- The degree of spontaneous LVOT gradient variability during a single cardiac catheterization is not well-characterized.
Purpose of the Study:
- To characterize the variability of LVOT gradient in patients with HCM during cardiac catheterization.
- To determine the potential for misclassification of obstruction severity due to spontaneous LVOT gradient fluctuations.
Main Methods:
- Fifty symptomatic HCM patients underwent cardiac catheterization using high-fidelity micromanometer-tip catheters.
- LVOT gradients were measured, and variability was calculated as the difference between the largest and smallest gradients without interventions.
Main Results:
- Significant spontaneous LVOT gradient variability was observed (mean 49.0 ± 53.1 mm Hg).
- Fifty percent of patients had discrepant classification of obstruction severity.
- Forty percent of patients with severe obstruction were at risk of misclassification.
Conclusions:
- LVOT gradients exhibit substantial spontaneous variability in HCM patients during hemodynamic assessment.
- This variability can lead to misclassification of obstruction severity in a significant proportion of patients.
- The dynamic nature of LVOT obstruction requires consideration during hemodynamic assessments and intervention evaluations.
Objectives:
This study characterizes left ventricular outflow tract (LVOT) gradient variability in patients with hypertrophic cardiomyopathy (HCM) during cardiac catheterization.
Background:
Management of HCM is directed by the presence and magnitude of LVOT obstruction. The magnitude and clinical impact of spontaneous variability during a single cardiac catheterization has not been described.
Methods:
Fifty symptomatic patients with HCM (mean age 55 ± 15 years; 48% men) underwent cardiac catheterization with high-fidelity, micromanometer-tip catheters and transseptal measurement of left ventricular pressures. Obstruction was defined as resting LVOT gradient ≥ 30 mm Hg and severe obstruction as ≥ 50 mm Hg. Variability in LVOT gradient was calculated as the difference of the largest and smallest LVOT gradients in the absence of provocative maneuvers or interventions.
Results:
The largest LVOT gradient was 54.6 ± 56.4 mm Hg. The spontaneous variability in LVOT gradient was 49.0 ± 53.1 mm Hg (range 0 to 210.8 mm Hg, median 15 mm Hg). Discrepant classification of resting LVOT gradient severity was possible in 25 patients (50%). Twenty patients (40%) with severe obstruction could have been misclassified with regard to obstruction severity.
Conclusions:
In patients with HCM, the LVOT gradient fluctuates significantly during a single hemodynamic assessment. Spontaneous variability could lead to misclassification of obstruction severity in one-half of studied patients. The dynamic nature of LVOT obstruction must be considered when assessing resting hemodynamics or the success of a given intervention during cardiac catheterization.
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