Electrocardiogram-synchronized pulsatile extracorporeal life support preserves left ventricular function and coronary flow in a porcine model of cardiogenic shock

<div><p>Introduction</p><p>Veno-arterial extracorporeal life support (ECLS) is increasingly being used to treat rapidly progressing or severe cardiogenic shock. However, it has been repeatedly shown that increased afterload associated with ECLS significantly diminishes left ventricular (LV) performance. The objective of the present study was to compare LV function and coronary flow during standard continuous-flow ECLS support and electrocardiogram (ECG)-synchronized pulsatile ECLS flow in a porcine model of cardiogenic shock.</p><p>Methods</p><p>Sixteen female swine (mean body weight 45 kg) underwent ECLS implantation under general anesthesia and artificial ventilation. Subsequently, acute cardiogenic shock, with documented signs of tissue hypoperfusion, was induced by initiating global myocardial hypoxia. Hemodynamic cardiac performance variables and coronary flow were then measured at different rates of continuous or pulsatile ECLS flow (ranging from 1 L/min to 4 L/min) using arterial and venous catheters, a pulmonary artery catheter, an LV pressure-volume loop catheter, and a Doppler coronary guide-wire.</p><p>Results</p><p>Myocardial hypoxia resulted in declines in mean cardiac output to 1.7±0.7 L/min, systolic blood pressure to 64±22 mmHg, and LV ejection fraction (LVEF) to 22±7%. Synchronized pulsatile flow was associated with a significant reduction in LV end-systolic volume by 6.2 mL (6.7%), an increase in LV stroke volume by 5.0 mL (17.4%), higher LVEF by 4.5% (18.8% relative), cardiac output by 0.37 L/min (17.1%), and mean arterial pressure by 3.0 mmHg (5.5%) when compared with continuous ECLS flow at all ECLS flow rates (P<0.05). At selected ECLS flow rates, pulsatile flow also reduced LV end-diastolic pressure, end-diastolic volume, and systolic pressure. ECG-synchronized pulsatile flow was also associated with significantly increased (7% to 22%) coronary flow at all ECLS flow rates.</p><p>Conclusion</p><p>ECG-synchronized pulsatile ECLS flow preserved LV function and coronary flow compared with standard continuous-flow ECLS in a porcine model of cardiogenic shock.</p></div

Pressure-volume loop analysis.

<p>LV, left ventricle; SBP, systolic blood pressure; LVESV, left ventricular end-systolic volume; LVEDV, left ventricular end-diastolic volume; LVEDP, left ventricular end-diastolic pressure.</p

Comparison of the effect of different levels of continuous (C) and electrocardiogram-synchronized pulsatile (P) extracorporeal blood flow (EBF) on coronary blood flow measured using an intracoronary Doppler wire in a porcine model of cardiogenic shock.

<p>*P<0.05.</p

Comparison of the effect of different levels of continuous (C) and synchronized pulsatile (P) extracorporeal blood flow (EBF) on left ventricular performance parameters in a porcine model of cardiogenic shock.

<p>(A) LVESV, left ventricle end-systolic volume; (B) LVSV, left ventricle stroke volume; (C) LVEF, left ventricle ejection fraction; (D) CO, cardiac output. *P<0.05.</p

Comparison of the effect of different levels of continuous (C) and synchronized pulsatile (P) extracorporeal blood flow (EBF) on hemodynamic and left ventricular performance parameters in a porcine model of cardiogenic shock.

<p>(A) MAP, mean arterial pressure; (B) SBP, systolic blood pressure; (C) LVEDP, left ventricle end-diastolic pressure; (D) LVEDV, left ventricle end-diastolic volume. *P<0.05.</p

Thirty-day mortality according to the BMI category and type of heart failure.

<p>Thirty-day mortality according to the BMI category and type of heart failure.</p

Baseline characteristics of patients before and after matching.

<p>*/**Statistical significance of differences between groups was tested by the ML chi-square test for categorical variables and by the independent Student’s <i>t</i>-test for continuous variables</p><p>*/**p<0.05/p<0.001</p><p>^aParameter used in a logistic regression model of a propensity score</p><p>^bParameter was not known for all patients, and statistics were computed on a reduced basis</p><p>^cMedication at discharge was computed on patients who were alive after discharge</p><p>LVEF—left ventricular ejection fraction, BP—blood pressure, MI—myocardial infarction, TIA—transient ischemic attack, PCI—percutaneous coronary intervention, CABG—coronary artery bypass graft, PM—pacemaker, ICD—implantable cardioverter–defibrillator, CRT—cardiac resynchronization therapy, COPD—chronic obstructive pulmonary disease, ARB—angiotensin-2 receptor blockers.</p><p>Baseline characteristics of patients before and after matching.</p

Baseline characteristics of patients after matching according to type of heart failure.

<p>*/**Statistical significance of differences between groups tested by the ML chi-square test for categorical variables and by the independent Student’s <i>t</i>-test for continuous variables</p><p>*/**p<0.05/p<0.001</p><p>^aParameters used in a logistic regression model of a propensity score</p><p>^bMedication at discharge was computed on patients who were alive after discharge</p><p>LVEF—left ventricular ejection fraction, BP—blood pressure, MI—myocardial infarction, TIA—transient ischemic attack, PCI—percutaneous coronary intervention, CABG—coronary artery bypass graft, PM—pacemaker, ICD—implantable cardioverter–defibrillator, CRT—cardiac resynchronization therapy, COPD—chronic obstructive pulmonary disease, ARB—angiotensin-2 receptor blockers.</p><p>Baseline characteristics of patients after matching according to type of heart failure.</p

Long-term mortality for all patients according to a BMI of 25 kg/m² in a non-balanced and balanced dataset and for ADHF and <i>de novo</i> AHF patients.

<p>Long-term mortality for all patients according to a BMI of 25 kg/m² in a non-balanced and balanced dataset and for ADHF and <i>de novo</i> AHF patients.</p

Definition of datasets.

<p>Definition of datasets.</p