Article

A40 - Unloading Left Ventricular Results in Right Ventricular Overloading in Large MI and Severe Left Ventricular Dysfunction

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Citation:Interventional Cardiology Review 2019;14(3 Suppl 1):A40.

Correspondence: Taro Kariya, kariya-tky@umin.org

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Background: Right ventricular (RV) failure develops after left ventricular assist device therapy (LVAD) implantation in up to 30% of patients. The impact of acute left ventricular (LV) unloading using catheter-based LVAD on RV remains unclear.

Hypothesis: RV failure similarly develops after Impella support in severe heart failure.

Methods: Yorkshire pigs (n=6) received LV Impella support 1 week after percutaneous induction of MI. The impact of LV Impella support on RV was studied using monitoring pressure and volume using a Millar catheter in the RV. Additionally, the incidence of RV failure was studied by reviewing all the subacute MI pigs that received Impella in our lab.

Results: Heart rate showed significant decrease with LV Impella support (P0: 98 ± 8 to P8: 83 ± 9 BPM, p=0.001). RV dilated progressively as the LV Impella flow was increased (RV end-diastolic volume P0: 61 ± 23, P2: 63 ± 25, P5: 68 ± 25, P8: 73 ± 25 ml, and RV end-systolic volume P0: 27 ± 22, P2: 28 ± 21, P5: 29 ± 22, P8: 30 ± 22 ml). There were no significant differences in the RV contractility parameters, including maximum pressure, maximum dP/dt and RV end-systolic pressure–volume relationship. In contrast, minimum dP/dt deteriorated (P0: −333 ± 84 to P8: −242 ± 50, p=0.02) with higher LV support.

A review of 38 pigs identified 12 (32%) which showed signs of RV failure that required reduction of Impella flow or catecholamine administration. LV and RV functional analysis revealed that pigs with larger infarction and severe LV dysfunction are more prone to RV failure (large infarct size, larger LV volume and lower ejection fraction). The mean pulmonary artery before LV Impella was not different between the animals that developed RV failure and those that did not (22 ± 7 versus 19 ± 6 mmHg, p=0.12). Meanwhile, the mean right atrial pressure prior to LV Impella was higher in the pigs that developed RV failure (4.8 ± 3.0 mmHg versus 2.3 ± 1.4 mmHg, p=0.02).

Conclusion: Impella LV support results in flow-dependent chamber dilation of the RV. RV systolic function remains unaltered, but the diastolic function may deteriorate. Animals with larger infarction and severe LV dysfunction were prone to develop RV failure.