High versus Normal Blood-Pressure Targets in relation to Right Ventricular Dysfunction after Cardiac Surgery: a Randomized Controlled Trial

URL: https://www.jcvaonline.com/article/S1053-0770(21)00189-0/fulltext

DOI: https://doi.org/10.1053/j.jvca.2021.02.054

Published: Journal of Cardiothoracic and Vascular Anesthesia (March 2021)

Authors: I.T. Bootsma, F. de Lange, T.W.L. Scheeren, J.S. Jainandunsing, E.C. Boerma

Article description

Right ventricular (RV) dysfunction is an underestimated clinical entity associated with low-cardiac-output syndrome and increased mortality after cardiac surgery.
Induced increases in blood pressure can improve right coronary artery blood flow, re-establish the transseptal gradient, and right ventricular (RV) and left ventricular dimensions, resulting in improved RV function.
Thus, the direct inotropic effect of norepinephrine (NE) on the right ventricle might be conceivable.
The investigators studied the norepinephrine-mediated effect of high versus normal blood pressure targets on RV function after cardiac surgery patients with a low (<20%) or moderate (20%-30%) RV ejection fraction (RVEF).
They hypothesized that higher blood pressure would improve RV function.

Summary:

The study included 78 patients who had postoperative RVEF <30% in combination with a mean arterial pressure (MAP) of ?65 mmHg within the first postoperative hour in the intensive care unit (ICU) after cardiac surgery through full sternotomy.
Patients were classified into two groups; (1) a low RVEF (<20%) and (2) moderate RVEF (between 20% and 30%), as measured by the PAC on admission to the ICU.
Postoperative ventilation was standardized using a respiratory frequency of 20-to-25 times per minute, tidal volumes of 6 mL/kg ideal body weight, and a postoperative end-expiratory pressure of 10 cmH2O.
In each group, patients were assigned randomly to either a normal-target blood pressure (MAP 65 mmHg) group or a high-target blood pressure (MAP 85 mmHg) group with titrating norepinephrine infusion.
The primary outcome was the change in RVEF over a one-hour study period.
In the RVEF<20%, there was no significant between-group difference in the change in RVEF (–1% [–3.3 to 1.8] in the normal-target group v 0.5% [–1 to 4] in the high- target group; p = 0.159).
Similarly, there was no significant between-group difference in the change in RVEF (–1% [–3 to 0] in the normal-target group v 1% [–1 to 3] in the high-target group; p = 0.074).
These observations were in line with the documented no improvements in RV echocardiographic parameters (i.e., TAPSE, S’, and myocardial performance index) in the intervention group.
The study is limited with the limited number of patients and the short window of one-hour observation.

Conclusions:

In a mixed population of patients with RV dysfunction after cardiac surgery, norepinephrine-mediated high-blood-pressure targets, increasing MAP from 65 mmHg to MAP 85 mmHg, did not increase PAC-derived RVEF compared with normal-blood-pressure targets.

Change in transesophageal echocardiographic parameters over time. The final transesophageal echocardiography measurement was performed after 60 minutes in the control group or in case the mean arterial pressure returned to 65 mmHg for the intervention group (timepoint 5). MPI, myocardial performance index; RVEF, right ventricular ejection fraction; S’, systolic myocardial contraction; TAPSE, tricuspid annular systolic plane excursion.