Does the Calculated LVEDP of Temporary Micro-axial Pumps Correlate with the Pulmonary Capillary Wedge Pressure and Hence Can Be Used as a Weaning Strategy?

Background: Micro-axial pumps are well-established temporary mechanical circulatory support devices (tMCS). Treatment strategies are bridge-to-recovery or bridge-to-decision, as well as high-risk elective cardiac surgeries. A new feature of the device is the capability of deriving the left ventricular end-diastolic pressure from the continuously measured LV-waveform. The objective was to evaluate the precision of this calculated LVEDP (cLVEDP) as compared to invasively measured pulmonary capillary wedge pressure (PCWP) while using Swan-Ganz-Catheters (SGC).

Methods: In this prospective single center study, all patients > 18 years of age in INTERMACS 1-4 were included. No differentiation was made with regard to etiology of heart failure or shock. All patients were routinely equipped with a SGC to monitor indexed cardiac output, PCWP, pulmonary artery pressure and right heart failure. PCWP and cLVEDP were measured simultaneously and a ratio was calculated to depict a correlation. We conducted five measurements over a period of ten minutes at an interval of eight hours (3 measurements per day) obtaining 15 measured data sets per day per patient. P-Levels, which represent the axial flow rate were also collected.

Results: We obtained a total of 55.66 Days on device with an overall of 550 measured data sets. 75% of the patients were male. Average age of all patients was 64.95y. Main reason for tMCS was ischemic heart disease and myocardial infarction. 62.5% of the patients had severely reduced ejection fraction (EF < 30%) at baseline. Most patients (80%) received right sided subclavian access, 15% direct aortic access and 5% femoral access. Mean PCWP was 14.82 mmHg, mean cLVEDP was 23.64 mmHg. Included P-Levels spanned from P-9 to P-4. So far, cLVEDP shows a correlation with PCWP, with an overestimation of the cLVEDP as compared with the PCWP. The correlation remained stable over all P-Levels and was independent from cardiac rhythm, preoperative left-ventricular function, concomitant procedure and additional extracorporeal life support.

Conclusion: This external validation suggests, that the cLVEDP derived by the micro-axial pump correlates with the PCWP enabling it as a continuous monitoring and weaning tool. This would facilitate tMCS therapy on ICU and reduce the need for repeated transthoracic and trans-esophageal echocardiography as well as SGC insertion simplifying weaning strategies.

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Artikel online veröffentlicht:
13. Februar 2024