Left Heart Pulsatility Index: Definition, Normal Values, and Clinical Interpretation
The term "left heart pulsatility index" is not a standard echocardiographic parameter in current cardiovascular guidelines, and the provided evidence does not define this specific metric for left ventricular assessment 1.
What the Evidence Actually Addresses
Standard Left Ventricular Diastolic Function Parameters
The ASE/EACVI guidelines recommend a comprehensive four-parameter algorithm for assessing left ventricular diastolic function, which includes 1:
- Mitral annular e′ velocity: septal e′ < 7 cm/sec or lateral e′ < 10 cm/sec indicates abnormal relaxation 1, 2
- Average E/e′ ratio: values > 14 suggest elevated left atrial pressure 1, 2
- Left atrial maximum volume index: > 34 mL/m² indicates chronic pressure elevation 1, 2
- Peak tricuspid regurgitation velocity: > 2.8 m/sec supports elevated filling pressures 1, 2
Pulsatility Index in Other Contexts
In peripheral vascular assessment, pulsatility index measures waveform characteristics in arterial flow but has significant limitations, particularly in combined segment disease where both proximal and distal PI fall with stenosis, potentially leading to misinterpretation 3.
In LVAD recipients, increased pulsatility index in carotid arteries (measured by duplex ultrasound) is associated with adverse outcomes, with hazard ratios of 9.8 (95% CI 1.62-59.42) for death and cerebrovascular events when measured at 3 months post-implantation 4. This risk is potentiated by increased arterial stiffness 4.
In general hemodynamics, central pulsatility (measured as central pulse pressure) relates to left ventricular function through forward and backward pulse wave components, though commercial wave separation algorithms have limited clinical utility with only 81.6% feasibility, particularly failing in older patients with unfavorable hemodynamics 5.
Clinical Interpretation Framework
If You Meant Myocardial Performance Index (MPI)
The myocardial performance index (also called Tei index) is a validated measure of combined systolic and diastolic function 6:
- Normal values by conventional pulsed-wave Doppler: < 0.50 6
- Normal values by tissue Doppler: < 0.60 6
- Heart failure cutoff (conventional method): ≥ 0.50 6
- Heart failure cutoff (tissue Doppler): ≥ 0.60 6
The tissue Doppler method has the advantage of deriving all measurements from a single cardiac cycle, eliminating heart rate variability interference 6.
If You Meant Arterial Pulsatility in Heart Failure
Pulsatile hemodynamics play a fundamental role in heart failure pathophysiology 7:
- Brachial pulse pressure is the simplest measure of pulsatility and is fundamentally associated with heart failure development and treatment 7
- Wave reflections relate closely to late systolic afterload, ventricular remodeling, diastolic dysfunction, and exercise capacity 7
- Central pulse pressure (rather than individual forward/backward wave components) is favored for predicting left ventricular dysfunction given the limited feasibility of wave separation analysis 5
Key Clinical Pitfalls
Avoid relying on automated wave separation algorithms in older patients or those with unfavorable hemodynamics, as these fail in approximately 18-20% of cases, particularly in older women 5.
Do not assume pulsatility index in peripheral vessels reflects cardiac function without considering the confounding effects of proximal stenoses, which reduce PI both above and below the lesion 3.
In LVAD patients, recognize that increased carotid pulsatility index paradoxically predicts worse outcomes, likely reflecting inadequate flow modulation and increased arterial stiffness 4. HeartMate 3 recipients show lower risk (HR 0.31,95% CI 0.11-0.91) compared to HeartMate II, though this benefit is attenuated by arterial stiffness 4.