Coronary Perfusion Pressure Formula
Coronary perfusion pressure equals aortic diastolic pressure minus left ventricular end-diastolic pressure (LVEDP). 1
Formula Components
The complete formula is:
CPP = Aortic Diastolic Pressure - LVEDP
Alternatively, coronary perfusion pressure can be calculated as:
CPP = Aortic Diastolic Pressure - Right Atrial Diastolic Pressure 1
Clinical Context and Rationale
Normal Physiology
- Myocardial perfusion occurs predominantly during diastole, making diastolic blood pressure the primary determinant of coronary perfusion pressure 1, 2
- In normal coronary arteries, aortic pressure transmits completely to distal coronary regions without appreciable pressure loss 1, 2
- The pressure gradient between the aorta and left ventricle during diastole drives coronary blood flow 1
Which Formula to Use
Use aortic diastolic pressure minus LVEDP as the primary formula 1, 2, as this represents the true driving pressure for myocardial perfusion. The alternative formula using right atrial pressure (aortic diastolic pressure minus right atrial diastolic pressure) is primarily used during cardiopulmonary resuscitation when simultaneous aortic and central venous pressure monitoring is available 1.
Clinical Significance
- A CPP threshold of 15 mm Hg during CPR is required for return of spontaneous circulation (ROSC) 1
- During CPR, aortic relaxation diastolic pressure must exceed 17 mm Hg for ROSC to occur 1
- In stable patients undergoing PCI, coronary perfusion pressure is calculated as mean arterial pressure minus LVEDP 3
Important Caveats
- Right ventricular coronary perfusion differs from left ventricular perfusion: RV perfusion occurs during both systole and diastole, unlike the predominantly diastolic LV coronary flow 1
- In pressure-overloaded right ventricles, decreased perfusion pressure combined with increased RV intramural pressure increases ischemia risk 1
- Central venous pressure can be substituted for LVEDP when measuring CPP during resuscitation, as simultaneous aortic and LV pressure measurement is rarely clinically available 1