Abstract
Heart transplant recipients (HTX) have several risk factors for heart failure which can trigger pro-inflammatory and fibrosis factors and set into motion pathophysiologic changes leading to diastolic dysfunction and HFpEF. The objective of the study was to determine if HTX recipients with dyspnea have diastolic dysfunction and HFpEF. Twenty-five HTX were included. LV systolic and diastolic functions were evaluated using conductance catheters to obtain pressure volume loops. LV function was assessed at rest and during moderate intensity exercise of the upper extremities. A significant increase occurred in LV minimal pressure (3.7 ± 3.3 to 6.5 ± 3.5 mmHg) and end diastolic pressure or EDP (11.5 ± 4 to 18 ± 3.8 mmHg, both P < 0.01) with exercise. With exercise, the time constant of LV relaxation shortened in 2, was unchanged in 3, and increased in the remaining patients (group results: rest 40 ± 11.6 vs 46 ± 9 ms, P < 0.01). LV chamber stiffness constant was abnormally increased in all but 2 patients. Indices of LV systolic properties were normal at rest but failed to augment with exercise. In 15 who agreed to blood draw, inflammation and fibrosis markers were obtained. A significant association was observed between LV EDP and Pro-Col III N-terminal (r = 0.58, P = 0.024) and IL-1-soluble receptor (r = 0.59, P = 0.02) levels. HTX have diastolic dysfunction and can develop HFpEF several years after cardiac transplantation. The abnormally increased LV chamber stiffness and the prolongation or lack of shortening of the time constant of LV relaxation with exercise are the underlying reasons behind the observed changes in LV diastolic pressures with exercise.
Highlights
Heart transplant recipients (HTX) have several risk factors for heart failure which can trigger proinflammatory and fibrosis factors and set into motion pathophysiologic changes leading to diastolic dysfunction and HFpEF
left atrial (LA) pressure does not exceed the upper limits of normal rest pressure in healthy subjects, except at very high cardiac output, allowing normal subjects to exercise without increased filling pressure[18,19]
Patients in this study developed a significant increase in left ventricular (LV) diastolic pressures with dyspnea despite low workload and very modest rise in heart rate that led to exercise termination
Summary
Heart transplant recipients (HTX) have several risk factors for heart failure which can trigger proinflammatory and fibrosis factors and set into motion pathophysiologic changes leading to diastolic dysfunction and HFpEF. LV systolic and diastolic functions were evaluated using conductance catheters to obtain pressure volume loops. The time constant of LV relaxation shortened in 2, was unchanged in 3, and increased in the remaining patients (group results: rest 40 ± 11.6 vs 46 ± 9 ms, P < 0.01). The abnormally increased LV chamber stiffness and the prolongation or lack of shortening of the time constant of LV relaxation with exercise are the underlying reasons behind the observed changes in LV diastolic pressures with exercise. There are few studies early after transplantation including few patients, reporting abnormal LV diastolic pressures[1,2], and deficient acceleration of relaxation with exercise[3].
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