Key Points
- Mechanical circulatory support (MCS) offers a surgical option for advanced heart failure when optimal medical therapy is inadequate.
- MCS therapy improves prognosis, functional status, and quality of life.
- Ambulatory patients with MCS can span the entire age spectrum from pediatrics to geriatrics.
- Because patients with MCS are becoming increasingly mobile, basic knowledge of equipment is necessary for personnel in public areas such as schools, public transportation, and airplanes/airports.
Diagnosis
Patient Evaluation
- The primary MCS team should be contacted for any patient-related emergencies.
- In non–life-threatening situations, care providers inexperienced with the management of MCS should defer device management to patients and their family caregivers until contact can be established with the MCS center or device company technical support.
- Whenever possible, emergency medical service providers who will be transporting a patients on MCS should also transport the patient’s backup and peripheral equipment.
- A Doppler probe and a manual cuff can be used to obtain blood pressure in a patient supported by continuous-flow MCS because the automated measurement of heart rate, pulse oximetry, and blood pressure may be unreliable in this setting.
- Once pump function is established, assessment of the unstable patient on MCS should begin with a general evaluation of the patient for the inciting condition (e.g., arrhythmia, hypovolemic or distributive shock, and acute blood loss).
- Outpatients who present with MCS device stoppage should not have the device restarted without the guidance of the primary MCS center.
Table 1. Recommended Diagnostics for Assessment of Patients on Mechanical Circulatory Support
| Chemistries |
| CBC |
| Urine analysis |
| LDH |
| PT/INR |
| ECG |
| Chest x-ray |
| Consider pacemaker interrogation |
Table 2. Stroke in Patients With a VAD
| Evaluation of Stroke | |
|---|---|
| Assessment | Purpose |
| PT/PTT, INR | Guide management of anticoagulation |
| Head CT scan | Assess severity and type of stroke (hemorrhagic vs. ischemic) |
| Doppler blood pressure | Manage hypertension |
| CTA of the neck and/or carotid Doppler (if not completed before LVAD insertion) | Assess for alternative causes of stroke |
| CT of the chest and CXR | Assess device positioning (look for kinking of cannula or device obstruction) |
| Neurology and/or neurosurgical consultation | Make recommendations for stroke management (BP guidelines, surgical intervention if hemorrhagic, etc.) |
Table 3. Causes of VAD Alarms
| Potential Causes | Advisory (Noncritical) | Critical |
|---|---|---|
| Power |
|
|
| Hardware |
|
|
| Low flow |
|
|
| High power |
| |
| Evaluation |
|
|
| Management options |
|
|
Pump Evaluation
- Device parameters such as power, speed, flow, and pulsatility should be recorded throughout the patient’s course.
Table 4. Normal Parameters
| RPM | Power, W | Flow, L/min | Pulsatility | |
|---|---|---|---|---|
| HeartMate II | 8000–10 000 | 5.0–8.0 | 4.0–7.0 | 5.0–8.0 |
| HeartWare Ventricular Assist Device | 2400–3200 | 3.0–7.0 | 3.5–7.0 |
- If battery power is low, either the batteries should be replaced or the configuration should be changed to wall power.
- When power source is confirmed but there is a persistent device alarm, the controller should be exchanged for the backup controller.
- If thrombus is suspected, assessment for hemolysis, including lactate dehydrogenase, is recommended.
Table 5. Indications and Contraindications to Durable Mechanical Support
| Indications– Combination of the following: |
|---|
| Frequent hospitalizations for heart failure |
| NYHA class IIIb–IV functional limitations despite maximal therapy |
| Intolerance of neurohormonal antagonists |
| Increasing diuretic requirement |
| Symptomatic despite CRT |
| Inotrope dependence |
| Low peak Vo2 (<14–16) |
| End-organ dysfunction attributable to low cardiac output |
| Contraindications |
| Absolute |
| Irreversible hepatic disease |
| Irreversible renal disease |
| Irreversible neurological disease |
| Medical nonadherence |
| Severe psychosocial limitations |
| Relative |
| Age >80 y for destination therapy |
| Obesity or malnutrition |
| Musculoskeletal disease that impairs rehabilitation |
| Active systemic infection or prolonged intubation |
| Untreated malignancy |
| Severe PVD |
| Active substance abuse |
| Impaired cognitive function |
| Unmanaged psychiatric disorder |
| Lack of social support |