Related Experiment Videos
Analysis of hemodynamic changes during beating heart surgical procedures
M Mathison1, J R Edgerton, J L Horswell
1Cardiopulmonary Research Science and Technology Institute, Dallas, Texas, USA.
Insights
Displacing the heart during off-pump coronary artery bypass grafting significantly impacts hemodynamics, particularly right ventricular diastolic filling. This study clarifies the mechanisms behind these hemodynamic changes in patients undergoing beating heart surgery.
Area of Science:
- Cardiovascular Surgery
- Cardiac Anesthesia
- Hemodynamics
Background:
- Off-pump coronary artery bypass grafting (CABG) involves heart manipulation, leading to hemodynamic compromise.
- Mechanisms of hemodynamic alterations during beating heart surgery are not fully understood.
Purpose of the Study:
- To define hemodynamic changes during heart displacement in off-pump CABG.
- To elucidate the causes of altered hemodynamics in beating heart procedures.
Main Methods:
- Studied 44 patients undergoing off-pump CABG.
- Measured hemodynamic variables before and after heart positioning for specific coronary artery anastomoses.
Main Results:
- Significant increases in right ventricular end-diastolic pressure (RVEDP) occurred during positioning for all target vessels.
- Left ventricular end-diastolic pressure (LVEDP) increased when positioning for LAD and circumflex arteries.
- Circumflex artery positioning caused the most significant RVEDP and LVEDP increases, indicating maximal hemodynamic compromise.
Conclusions:
- Biventricular dysfunction contributes to altered hemodynamics in patients with diseased hearts during off-pump CABG.
- Disturbed diastolic filling of the right ventricle, likely due to direct compression, is the primary cause of hemodynamic changes.
- Understanding these mechanisms is crucial for managing patients undergoing beating heart surgery.
Background:
Coronary artery bypass grafting on the beating heart causes significant hemodynamic compromise during displacement of the heart. The precise mechanisms causing altered hemodynamics have not been clearly understood. The purpose of this study was to define the hemodynamic changes caused by displacing the heart in patients undergoing beating heart surgical procedures.
Methods:
Forty-four patients (35 men, 9 women; mean age, 64.5 +/- 9.6 years) underwent off-pump coronary artery bypass grafting. The hemodynamic variables were collected before and after positioning the heart for anastomosis of the left anterior descending, circumflex, and posterior descending coronary arteries.
Results:
There was a significant increase in right ventricular end-diastolic pressure during positioning for all vessels, and in left ventricular end-diastolic pressure during positioning for the left anterior descending and circumflex coronary arteries. Positioning for the circumflex artery showed the largest increase of left and right ventricular end-diastolic pressure, resulting in the greatest hemodynamic compromise.
Conclusions:
In the clinical setting of diseased human hearts, there is a biventricular contribution to altered hemodynamics. The increase of right ventricular end-diastolic pressure in all positions suggests that the major cause of hemodynamic changes is disturbed diastolic filling of the right ventricle, especially by direct ventricular compression.