Target Mean Arterial Pressure After Brio VAD Implantation
Maintain a mean arterial pressure (MAP) in the normal range, specifically targeting 70-90 mmHg, while avoiding sustained MAP >90 mmHg to reduce stroke risk and ensuring MAP does not fall below 65 mmHg to maintain adequate organ perfusion. 1, 2
Primary MAP Target Range
The goal MAP after VAD implantation should be maintained in the "normal range" as emphasized by the American Heart Association guidelines for mechanical circulatory support, with titration of medical therapy imperative to optimize forward flow and prevent adverse events. 1
A MAP greater than 90 mmHg is specifically associated with increased stroke risk in VAD patients, particularly hemorrhagic stroke, based on data from the HeartWare Ventricular Assist Device studies. 2
The lower threshold of MAP ≥65 mmHg represents the critical perfusion pressure below which organ autoregulation fails and tissue perfusion becomes linearly dependent on arterial pressure. 3
Practical MAP Management Algorithm
Initial Post-Operative Period
Target MAP of 70-80 mmHg during the immediate post-operative phase (first 48 hours), as vasoplegia requiring vasopressors to maintain MAP >70 mmHg is common and associated with adverse outcomes including increased mortality. 4
Monitor the MAP-to-CVP ratio, ensuring it remains ≥7.5, as ratios <7.5 predict right ventricular failure (44% vs 23% incidence) and increased mortality after LVAD placement. 5
Chronic Outpatient Management
Maintain MAP between 70-90 mmHg through aggressive antihypertensive therapy, as hypertension develops rapidly after CF-LVAD implantation with MAP increasing by 12.2% (from 77.6 to 87.1 mmHg) within 6 months. 6
Initiate or uptitrate neurohormone-modifying agents (ACE inhibitors, ARBs, beta-blockers) to decrease afterload, improve pump function, and potentially contribute to ventricular recovery while maintaining target MAP. 1
The most common effective antihypertensive regimens in VAD patients are beta-blocker monotherapy or beta-blocker plus ACE inhibitor combination. 6
Critical Monitoring Parameters Beyond MAP
Assess alternate measures of perfusion in addition to MAP, as pulse may not be palpable in 81% of VAD patients, including mental status, skin perfusion, capillary refill, and urine output (goal ≥0.5 mL/kg/h). 3, 7
Calculate trans-device perfusion pressure (MAP minus CVP) and maintain >60 mmHg, as elevated CVP critically reduces net perfusion pressure independent of cardiac output. 3, 5
Monitor pump parameters including flow, RPM, power, and pulsatility to ensure adequate device function while titrating blood pressure. 1
Common Pitfalls and How to Avoid Them
Do not allow MAP to exceed 90 mmHg chronically, as this significantly increases stroke risk—particularly hemorrhagic events—requiring prompt antihypertensive escalation. 2
Avoid assuming adequate perfusion based solely on MAP; increased afterload from hypertension decreases pump flow and increases risk of neurological events and end-organ damage despite "acceptable" MAP values. 1
Do not target MAP <65 mmHg even if the patient appears clinically stable, as this represents the critical threshold for organ autoregulation failure. 3
Recognize that blood pressure alone does not reflect cardiac output or adequate tissue perfusion—elevated systemic vascular resistance can maintain MAP despite critically low stroke volume index. 3
Special Considerations for Emergency Situations
In emergency settings, assess MAP using Doppler ultrasound or automated cuff with mean pressure display, as manual palpation of pulse is unreliable in VAD patients. 7
Maintain MAP ≥65 mmHg as the absolute minimum threshold during resuscitation, with consideration for higher targets (70-80 mmHg) if the patient has chronic hypertension or elevated CVP. 3, 4
If MAP falls below target despite adequate pump function, initiate norepinephrine as first-line vasopressor, particularly in the setting of post-operative vasoplegia. 3, 4