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Recovery of systolic and diastolic left ventricular function early after cardiopulmonary bypass
S G De Hert1, I E Rodrigus, L R Haenen
1Department of Anesthesiology, University of Antwerp, Belgium.
Insights
Left ventricular function significantly recovers within minutes after cardiopulmonary bypass (CPB) due to preload restoration. This rapid recovery suggests time-dependent changes in systolic and diastolic cardiac function post-CPB.
Area of Science:
- Cardiology
- Cardiac Surgery
- Physiology
Background:
- Left ventricular (LV) dysfunction post-cardiopulmonary bypass (CPB) is known, but early recovery patterns are unclear.
- Understanding early LV functional recovery after CPB is crucial for optimizing patient outcomes in coronary artery surgery.
- This study investigates the time course of LV function recovery immediately after CPB and its relation to preload.
Purpose of the Study:
- To evaluate the early recovery of left ventricular (LV) systolic and diastolic function after cardiopulmonary bypass (CPB).
- To determine if preload restoration contributes to the autoregulation of cardiac function following CPB.
- To compare LV function recovery between standard CPB separation and a protocol with optimal pre-separation filling.
Main Methods:
- Left ventricular pressure was measured using fluid-filled catheters and digitally recorded.
- Systolic function (Ees) and diastolic function (Kc) were assessed using pressure-volume relations.
- Cardiac function was measured before CPB, immediately after CPB, and at 5, 10, and 15 minutes post-CPB.
- Two protocols were compared: standard CPB separation (n=24) and optimal pre-separation filling (n=12).
Main Results:
- In the standard protocol, LV systolic function (Ees) significantly improved within 10 minutes post-CPB (P=0.001).
- Diastolic function (Kc) also showed significant improvement, decreasing within 10 minutes post-CPB (P=0.001).
- Patients in the optimal filling protocol did not exhibit significant systolic or diastolic dysfunction post-CPB, with stable function throughout observation.
Conclusions:
- Significant and rapid functional recovery of the left ventricle occurs early after separation from CPB.
- The observed recovery suggests time-dependent changes in LV systolic and diastolic function are influenced by preload restoration.
- Optimizing preload before CPB separation may prevent early post-CPB cardiac dysfunction.
Background:
Impairment of left ventricular function after cardiopulmonary bypass (CPB) is well recognized, but little is known about the time course of recovery of cardiac function early after separation from CPB. Therefore, recovery of left ventricular function was evaluated early after separation from CPB in patients undergoing coronary artery surgery. The authors tried to determine whether this recovery might be attributed to autoregulation of function by preload.
Methods:
Left ventricular pressure was measured with fluid-filled catheters. Data were digitally recorded during increased pressure induced by elevating the legs. Transgastric short-axis echocardiographic views of the left ventricle were simultaneously recorded on videotape. Systolic function was evaluated with the slope (Ees, mmHg/ml) of the systolic pressure-volume relation. Diastolic function was evaluated with the chamber stiffness constant (Kc, ml-1) of the diastolic pressure-volume relation. Cardiac function was assessed before CPB, after termination of CPB, and 5, 10, and 15 min later. Two different separation procedures from CPB were compared: in protocol 1, left ventricular function was documented during the standard procedure (n = 24); in protocol 2, the heart was optimally filled 10 min before separation from CPB (n = 12).
Results:
In protocol 1, Ees was 2.88 +/- 0.21 mmHg/ml (mean +/- SEM) and Kc was 0.012 +/- 0.001 ml-1 before CPB. Within 10 min after separation from CPB, Ees increased from 1.10 +/- 0.32 to 2.92 +/- 0.34 (P = 0.001) and Kc decreased from 0.022 +/- 0.002 to 0.011 +/- 0.001 (P = 0.001). The parameters remained stable thereafter. In protocol 2, Ees was 2.92 +/- 0.51 mmHg/ ml and Kc was 0.011 +/- 0.002 ml-1 before CPB. Depression of systolic and diastolic function was not observed in these patients. At time 0, Ees was 2.46 +/- 0.16 and Kc was 0.012 +/- 0.002. These values remained stable throughout the entire observation period.
Conclusions:
Significant functional recovery was observed early after separation from CPB, which was suggestive of time-dependent changes in both systolic and diastolic left ventricular function induced by preload restoration.