56 y/o male with past medical history of nonischemic cardiomyopathy (EF 15%) was admitted with cardiogenic shock requiring levophed. Physical examination was consistent with wet and cold state.
Here are VEXUS findings:
1. IVC: diameter 2.29 cm. Note that diameter > 2 cm is required to use VEXUS grading.
2. Hepatic vein doppler:
The single positive waveform here is S wave, and negative waveform below baseline is D wave. This is S wave reversal which is severely abnormal pattern.
Normally, in RV contraction, annulus is pulled down, which drops the pressure in RA leading to return of blood from hepatic vein towards RA. S wave reversal reflects impaired forward blood flow and atrial contraction-induced backward movement, influenced by altered tricuspid annulus movement and diminished right ventricular function. In simple words, RV gets so filled with volume and that there is no room left for the tricuspid annulus to come downward in RV cavity during RV contraction.
2. Portal vein doppler:
Pulsatiity here is > 50% consistent with severely abnormal patten.
In severe venous congestion, there is an increase in retrograde flow from the hepatic veins, creating resistance within the hepatic sinusoids and impairing the normal hepatopetal flow in the portal vein. This results in a progressively pulsatile flow and, in advanced cases, a biphasic pattern.
Hepatic sinusoids which lie in liver parenchyma between portal vein and hepatic vein, have the capacity to expand and contract, allowing them to absorb pressure fluctuations and dampen the pulsatile flow. Hence, normal flow is < 30% pulsatile. However, in severe volume overload and venous congestion.
3. Intra Renal Venous Doppler:
As interlobar renal artery and vein run in bundles, pulse doppler will capture flow from both simultaneously. Since the direction of flow would be the opposite to each other-the positive waveforms above baseline represents interlobar renal artery, whereas the negative waveforms represents interlobar vein.
Here, the flow is only occurring during diastole when cardiac relaxation allows for the emptying of central veins in the right heart. This absent flow in systole is due to volume overload and increased CVP. Normally, renal veins exhibit continuous monophasic flow during both systole and diastole.
Tricks to interpret hepatic venous doppler without real time EKG tracing:
Although, EKG tracing is needed to interpret a hepatic venous doppler accurately, there are two tricks which can help in interpretation:
1. Comparison with renal venous doppler:
Using intrarenal venous Doppler can help in the interpretation of hepatic vein Doppler waveforms by providing a reference point within the same cardiac cycle. By comparing the IRV waveform with the HV waveform,
Here, hepatic venous doppler and intra renal venous doppler are stacked in a way that they aligning them based on cardiac cycles. Since there is only one negative deflection per cycle, it tells us that vein is emptying in either only in systole or only in diastole. However, pathophysiologically, there is almost no way that venous emptying would happen in systole and no flow in diastole!
2. Based on morphology:
This would be a less acuurate way. Also, this can only be helpful in ruling out Severely abnormal pattern- S wave reversal. If there are no upward deflections, it is assumed that there is no S wave reversal. On the other side, if there is a single prominent upward deflection along with one negative deflection, then that would suggest S wave reversal.
For reference: VEXUS grading and patterns:
Author:
Neev Patel, MD
Comentarios