Residency · Residency · Cardiothoracic Surgery
Left Ventricular Assist Devices: Implantation and Management
Introduction
Left ventricular assist devices (LVADs) are implantable mechanical circulatory support systems that augment cardiac output in patients with advanced heart failure. With the evolution from pulsatile to continuous-flow technology, contemporary devices such as the HeartMate 3 provide durable support with improved hemocompatibility, serving as bridge to transplant, bridge to decision, or destination therapy.
Indications and Patient Selection
Indications
LVADs serve multiple strategic roles in the management of advanced heart failure. Bridge to transplant (BTT) addresses hemodynamic deterioration while awaiting a donor organ. Destination therapy (DT) provides permanent support for patients who are ineligible for transplantation. Bridge to candidacy allows optimization of end-organ function so that transplant eligibility can be reassessed. Bridge to recovery, though rare, applies in select cases of myocarditis or peripartum cardiomyopathy where ventricular function may return.
Patient Selection Criteria
Candidates for LVAD implantation typically present with NYHA Class IIIB-IV heart failure despite optimal medical therapy, a left ventricular ejection fraction below 25%, peak VO2 less than 14 mL/kg/min or inability to perform exercise testing, and dependence on continuous inotropic support or temporary mechanical circulatory support.
Contraindications and Risk Assessment
Contraindications include irreversible end-organ dysfunction such as hepatic cirrhosis or fixed pulmonary hypertension with PVR exceeding 5 Wood units, active systemic infection or coagulopathy, significant right ventricular failure (assessed via echocardiography, hemodynamics, and risk scores such as the RVFRS or Michigan score), and psychosocial barriers to device management and compliance.
Surgical Technique
Preoperative Preparation
Preoperative optimization involves ensuring adequate right ventricular function, nutritional status, and coagulation parameters. Active infections must be addressed before implantation. The absence of aortic regurgitation should be confirmed, as AR worsens with LVAD support. The driveline exit site should be planned and marked preoperatively.
Implantation via Median Sternotomy
The standard approach uses a full median sternotomy with institution of cardiopulmonary bypass. The inflow cannula is placed by coring the left ventricular apex, ensuring alignment toward the mitral valve, and securing it with a sewing ring and pledgeted sutures. The outflow graft is anastomosed end-to-side to the ascending aorta using a partial occlusion clamp, with careful orientation to avoid kinking. The centrifugal pump is placed in an intrapericardial pocket. The driveline is tunneled subcutaneously from the pump to a right upper quadrant exit site, following a gentle curve to minimize infection risk. The circuit is de-aired meticulously under TEE guidance before initiating flow, and the patient is weaned from cardiopulmonary bypass with gradual LVAD speed increases.
Less Invasive Approaches
A left thoracotomy with upper hemisternotomy for the outflow graft avoids a full sternotomy and is particularly beneficial in redo operations or bridge to transplant patients. This approach requires careful preoperative CT planning to identify the optimal intercostal space for access.
Postoperative Management
Hemodynamic Goals
Target mean arterial pressure is 70-80 mmHg, measured by Doppler since pulsatility is diminished. LVAD flows are typically maintained at 4-6 L/min with pump speed optimized to avoid septal shift or suction events. Right ventricular function must be monitored closely, with inotropic support using milrinone or epinephrine as needed.
Anticoagulation and Antiplatelet Therapy
Warfarin is maintained with an INR target of 2.0-3.0 according to device-specific protocols, along with aspirin at 81-325 mg daily. The HeartMate 3's fully magnetically levitated design reduces thrombogenicity, and some centers employ lower INR targets accordingly.
Driveline Care
Driveline management includes sterile dressing changes per institutional protocol, immobilization of the driveline to prevent traction and trauma, and comprehensive patient and caregiver education on infection prevention.
Complications
Device Thrombosis
Device thrombosis manifests as rising power consumption with power spikes, elevated LDH, and decreased flows. Management involves intensifying anticoagulation, administering thrombolytics, or performing device exchange. This complication has been significantly reduced with the HeartMate 3 compared to prior-generation devices.
Right Ventricular Failure
Right ventricular failure occurs in 20-30% of patients after LVAD implantation. It is managed with inotropes, inhaled nitric oxide, and occasionally temporary RVAD support.
Bleeding
GI bleeding is the most common hemorrhagic complication, related to acquired von Willebrand syndrome and arteriovenous malformations. Management strategies include reducing pump speed to restore pulsatility, octreotide administration, and endoscopic intervention.
Infection
Driveline infections are the most frequent infectious complication. Pump pocket and bloodstream infections carry significant morbidity and may require chronic suppressive antibiotics or surgical debridement.
Stroke
Both ischemic and hemorrhagic strokes occur, necessitating maintenance of optimal blood pressure and anticoagulation.
LVAD Complications Summary
| Complication | Incidence | Mechanism | Key Management |
|---|---|---|---|
| Device thrombosis | Reduced with HeartMate 3 | Thrombus in pump or outflow graft | Intensify anticoagulation; thrombolytics; device exchange |
| RV failure | 20-30% | Septal shift; increased RV preload | Inotropes (milrinone); inhaled NO; temporary RVAD |
| GI bleeding | 20-30% | Acquired von Willebrand syndrome; AVMs | Reduce pump speed; octreotide; endoscopy |
| Driveline infection | 15-20% | Exit site colonization; biofilm | Sterile dressing care; antibiotics; surgical debridement |
| Stroke (ischemic/hemorrhagic) | 10-15% | Thromboembolism; hypertension | MAP < 80 mmHg; optimal anticoagulation |
| Pump pocket infection | 5-10% | Surgical site contamination | Antibiotics; surgical washout |
| Aortic regurgitation | Progressive over time | Continuous flow across a closed aortic valve | Monitor by echo; may require surgical correction |
Key Clinical Pearls
Preoperative assessment of right ventricular function is the most critical determinant of postoperative success. Meticulous de-airing under TEE guidance prevents catastrophic air embolism at LVAD initiation. Blood pressure in LVAD patients must be measured by Doppler due to diminished pulsatility, with a target MAP below 80 mmHg to reduce stroke risk. GI bleeding management often requires a multidisciplinary approach combining pump speed reduction, endoscopy, and hematologic optimization. Patient and caregiver education on controller alarms, battery management, and emergency protocols is essential before discharge.
References
- Mehra MR, Uriel N, Naka Y, et al. A fully magnetically levitated left ventricular assist device: final report. N Engl J Med. 2019;380(17):1618-1627.
- Kirklin JK, Pagani FD, Kormos RL, et al. Eighth annual INTERMACS report: special focus on framing the impact of adverse events. J Heart Lung Transplant. 2017;36(10):1080-1086.
- Goldstein DJ, Meyns B, Xie R, et al. Third annual report from the ISHLT mechanically assisted circulatory support registry. J Heart Lung Transplant. 2019;38(2):114-126.
- Maltais S, Kilic A, Nathan S, et al. Prevention of HeartMate 3 pump thrombosis through clinical management. Ann Thorac Surg. 2017;103(1):116-124.