Q21 / 110
After peripheral VA-ECMO for AMI shock, a patient develops worsening pulmonary edema despite improved blood pressure. What mechanism best explains this?
Correct answer: B — Increased LV afterload from retrograde aortic flow with inadequate LV ejection
Retrograde aortic return raises LV afterload. A severely failing LV may not eject, causing LV, LA, and pulmonary venous pressure to rise. A does not cause pulmonary congestion in this manner. C is not the central mechanism. D incorrectly links venous drainage to pulmonary venous hypertension.
Board pearl: VA-ECMO may improve systemic perfusion while worsening LV loading.
Retrograde aortic return raises LV afterload. A severely failing LV may not eject, causing LV, LA, and pulmonary venous pressure to rise. A does not cause pulmonary congestion in this manner. C is not the central mechanism. D incorrectly links venous drainage to pulmonary venous hypertension.
Board pearl: VA-ECMO may improve systemic perfusion while worsening LV loading.
Q22 / 110
Which finding most strongly indicates clinically important LV overload and the need to initiate active LV unloading during VA-ECMO?
Correct answer: B — Moderate-to-severe LV smoke with absent aortic valve opening
Moderate-to-severe LV smoke with absent aortic valve opening most strongly indicates clinically important LV overload and the need to initiate active LV unloading during VA-ECMO. Ezad et al. Unloading the Left Ventricle in Venoarterial ECMO: In Whom, When, and How? is an excellent review article on the study of LV unloading on VA-ECMO. Of note, studies underway now for best method of unloading include the HERACLES trial and the EARLY-UNLOAD trial. The point is not just that a number is abnormal; this physiology identifies risk for pulmonary edema, thrombus, and failed myocardial recovery.
Board pearl: Ezad et al. is an excellent review article on LV unloading during VA-ECMO, and the best unloading method remains an active trial question.
Moderate-to-severe LV smoke with absent aortic valve opening most strongly indicates clinically important LV overload and the need to initiate active LV unloading during VA-ECMO. Ezad et al. Unloading the Left Ventricle in Venoarterial ECMO: In Whom, When, and How? is an excellent review article on the study of LV unloading on VA-ECMO. Of note, studies underway now for best method of unloading include the HERACLES trial and the EARLY-UNLOAD trial. The point is not just that a number is abnormal; this physiology identifies risk for pulmonary edema, thrombus, and failed myocardial recovery.
Board pearl: Ezad et al. is an excellent review article on LV unloading during VA-ECMO, and the best unloading method remains an active trial question.
Source(s): Ezad et al. Unloading the Left Ventricle in Venoarterial ECMO: In Whom, When, and How? Circulation. 2023 Apr;147(16). https://doi.org/10.1161/CIRCULATIONAHA.122.062371. | HERACLES trial: Hemodynamic Effects of Reducing Left Ventricular Afterload with Impella or Intraaortic Balloon Counterpulsation During Venoarterial Extracorporeal Membrane Oxygenation in Cardiogenic Shock. | EARLY-UNLOAD trial: Early Left Atrial Septostomy Versus Conventional Approach After Venoarterial Extracorporeal Membrane Oxygenation.
Q23 / 110
In the Schrage multicenter registry, early active LV unloading meant Impella implantation at what time?
Correct answer: C — Before or within 2 hours after VA-ECMO initiation
The Schrage multicenter registry defined early active LV unloading as Impella implantation before or within 2 hours after VA-ECMO initiation. That said, this question is most useful when interpreted through the outcomes of the study. Use of left ventricular unloading, primarily Impella CP in 67% of cases followed by Impella 2.5 in 22% and Impella 5.0 in 5%, resulted in lower mortality despite higher complication rates, including severe bleeding, access-site-related ischemia, abdominal compartment syndrome, and renal replacement therapy.
Board pearl: Schrage is most useful when interpreted through its outcomes: lower mortality despite higher complication rates.
The Schrage multicenter registry defined early active LV unloading as Impella implantation before or within 2 hours after VA-ECMO initiation. That said, this question is most useful when interpreted through the outcomes of the study. Use of left ventricular unloading, primarily Impella CP in 67% of cases followed by Impella 2.5 in 22% and Impella 5.0 in 5%, resulted in lower mortality despite higher complication rates, including severe bleeding, access-site-related ischemia, abdominal compartment syndrome, and renal replacement therapy.
Board pearl: Schrage is most useful when interpreted through its outcomes: lower mortality despite higher complication rates.
Q24 / 110
Which statement best summarizes the Schrage timing study?
Correct answer: A — Early unloading reduced mortality but increased complications
The Schrage timing study is best summarized as early unloading reduced mortality but increased complications. Schrage et al. did have an increase in major complications. This remains an observational association rather than causal proof, but the complication tradeoff should not be minimized.
Board pearl: Schrage et al. did have an increase in major complications.
The Schrage timing study is best summarized as early unloading reduced mortality but increased complications. Schrage et al. did have an increase in major complications. This remains an observational association rather than causal proof, but the complication tradeoff should not be minimized.
Board pearl: Schrage et al. did have an increase in major complications.
Q25 / 110
What is the principal conceptual difference between LV venting and LV unloading?
Correct answer: B — Venting primarily reduces pulmonary congestion; unloading primarily reduces myocardial work to promote recovery
LV venting and LV unloading are not fully synonymous. Venting primarily reduces pulmonary congestion and stasis, whereas unloading primarily reduces myocardial work to promote recovery. See the Ezad et al. review (https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.122.062371) for a fuller discussion of the conceptual distinction and how a given device may accomplish both goals to different degrees.
Board pearl: See Ezad et al. for a fuller discussion of the distinction between venting and unloading.
LV venting and LV unloading are not fully synonymous. Venting primarily reduces pulmonary congestion and stasis, whereas unloading primarily reduces myocardial work to promote recovery. See the Ezad et al. review (https://www.ahajournals.org/doi/10.1161/CIRCULATIONAHA.122.062371) for a fuller discussion of the conceptual distinction and how a given device may accomplish both goals to different degrees.
Board pearl: See Ezad et al. for a fuller discussion of the distinction between venting and unloading.
Source(s): Ezad et al. Unloading the Left Ventricle in Venoarterial ECMO: In Whom, When, and How? Circulation. 2023 Apr;147(16). https://doi.org/10.1161/CIRCULATIONAHA.122.062371.