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Diastolic Filling in Patients After Heart Transplantation Is Impaired Due to an Altered Geometrical Relationship
Katarina Steding-Ehrenborg1,2, Anders Nelsson1,2, Erik Hedström1,2,3,4
1Clinical Physiology, Department of Clinical Sciences Lund Lund University Lund Sweden.
Insights
Heart transplant surgery can impair diastolic filling by altering the geometry between the left atrium and ventricle. Modifying surgical techniques to reduce left atrial size may improve heart function.
Area of Science:
- Cardiology
- Cardiac Physiology
- Transplantation Medicine
Background:
- The geometric relationship between atrial and ventricular cross-sectional areas influences intracardiac blood flow and diastolic filling.
- Standard heart transplantation (HTx) surgical techniques often result in left atrial enlargement.
- Altered geometry may impact diastolic function in HTx recipients.
Purpose of the Study:
- To investigate the hypothesis that surgical alterations in the atrium-ventricle geometry affect diastolic filling in heart transplant patients.
- To compare the geometric and volumetric characteristics of the left atrium and ventricle in HTx patients versus control groups.
Main Methods:
- Retrospective, cross-sectional study involving 25 HTx patients, 15 heart failure with reduced ejection fraction (HFrEF) patients, 15 heart failure with preserved ejection fraction (HFpEF) patients, and 15 healthy controls.
- Cardiac magnetic resonance imaging (CMR) was used to obtain left ventricular, atrial, and total heart volumes.
- Atrioventricular area difference was calculated as the largest ventricular short-axis area minus the largest atrial short-axis area at end diastole and end systole.
Main Results:
- Left atrial minimum volume normalized for total heart volume (LAmin/THV) was significantly larger in HTx patients compared to controls (0.13 vs. 0.05, P <0.001).
- Left ventricular end-diastolic volume normalized for THV was similar between HTx patients and controls.
- A negative atrioventricular area difference at end diastole, indicative of impaired diastolic filling, was observed in 44% of HTx patients.
Conclusions:
- Diastolic filling is impaired in heart transplant recipients due to an altered geometric relationship between the left atrium and ventricle.
- Surgical techniques that minimize left atrial enlargement during cardiac transplantation could potentially enhance diastolic filling by optimizing hydraulic forces.
Background:
The geometrical relationship between atrial and ventricular short-axis cross-sectional area determines the hydraulic forces acting on intracardiac blood. This is important for diastolic filling. In patients undergoing heart transplantation (HTx), the left atrium is often enlarged as a result of the standard surgical technique. We hypothesized that diastolic filling in HTx patients is affected by the surgery altering the geometrical relationship between atrium and ventricle.
Methods And Results:
This retrospective, cross-sectional study included 25 HTx patients (median age, 52 [range, 25-70] years), 15 patients with heart failure with reduced ejection fraction (median age, 63 [range, 52-75] years), 15 patients with heart failure with preserved ejection fraction (median age, 74 [range, 56-82] years), and 15 healthy controls (median age, 64 [range, 58-67] years) who underwent cardiac magnetic resonance imaging. Left ventricular, atrial, and total heart volumes (THV) were obtained. Atrioventricular area difference at end diastole and end systole was calculated as the largest ventricular short-axis area minus the largest atrial short-axis area. Left atrial minimum volume normalized for THV (LAmin/THV) was larger in HTx patients (median, 0.13 [range, 0.07-0.19]) compared with controls (median, 0.05 [range, 0.03-0.08], P <0.001), whereas left ventricular volume normalized for THV (left ventricular end-diastolic volume/THV) was similar between HTx and controls (median, 0.19 [range, 0.12-0.24] and median, 0.22 [range, 0.20-0.25], respectively). At end diastole, when atrioventricular area difference reached its largest positive value in controls, 11 HTx patients (44%) had a negative atrioventricular area difference, indicating impaired diastolic filling.
Conclusions:
Diastolic filling is impaired in HTx patients due to an altered geometrical relationship between the left atrium and ventricle. When performing cardiac transplantation, a surgical technique that creates a smaller left atrium may improve diastolic filling by aiding hydraulic forces.
