Cardiac Assist Devices: Saving Lives Through Advanced Mechanical Circulatory Support

Cardiac Assist Devices

The human heart works tirelessly day and night to pump oxygenated blood throughout the body. However, there are times when the heart begins to fail due to conditions like heart attacks, cardiomyopathy or congestive heart failure. When the heart loses its ability to sufficiently pump blood on its own, cardiac assist devices step in to help. These mechanical circulatory support devices have evolved tremendously over the past few decades and are now capable of sustaining patients long-term or serving as a "bridge to transplant/recovery". In this article, we will explore the different types of cardiac assist devices available today and how they are improving outcomes for heart failure patients.

Ventricular Assist Devices

One of the most commonly used forms of mechanical circulatory support is Left Ventricular Assist Devices (LVADs). LVADs are implanted surgically and used for both short-term and long-term support of the left ventricle, which is responsible for pumping oxygenated blood out to the body. Contemporary LVAD designs consist of an internal pump that is placed into the failing left ventricle and an external controller and batteries worn on a belt or carried in a shoulder bag. The internal pump augments the natural pumping action of the heart, increasing cardiac output and blood flow to vital organs. LVADs can be used to stabilize patients awaiting a heart transplant or even provide permanent long-term support for those in end-stage heart failure.

Biventricular Assist Devices (BiVADs) perform a similar function but feature two pumps - one for each ventricle. BiVADs are needed in cases of severe biventricular failure affecting both lower chambers of the heart. Examples of commonly used LVADs and BiVADs include the HeartMate II, HeartMate 3, HeartWare HVAD and ABIOMED AB5000 BVS. Thesedevices haveassistedthousandsofpatientsinthe past few decades.Innovations like smaller pump sizes, magnetically levitated rotor technologies and wireless external components have reduced complications and made long-term support more feasible.

Short-Term Circulatory Support with VADs

In emergency situations, short-term Cardiac Assist Devices can serve as a bridge to decision or recovery for critically ill cardiac patients. For instance, the Impella device consists of a small catheter mounted pump that is percutaneously inserted into the left ventricle via the femoral artery.This provides immediate hemodynamic support for up to 5 days to stabilize the patient and allow time for definitive medical or surgical intervention. Other short-term options include the TandemHeart and CentriMag VAD systems which utilize external consoles connected to arterial and venous cannulae placed transcutaneously. These non-invasive short-term VADs allow stabilization of patients in cardiogenic shock prior to long-term device implantation or heart transplant.

Total Artificial Hearts

For patients with end-stage biventricular failure, Total Artificial Hearts (TAHs) may be recommended as "bridges to transplant". The SynCardia Temporary Total Artificial Heart and CARMAT total bioprosthetic artificial heart represent some of the TAH options available. These devices completely replace the native heart and involve removal of both ventricles. The artificial heart consists of two pneumatically driven pumps placed in the pericardial space that mimic natural cardiac function. An external console is connected through drivelines tunneled under the skin to power the internal pumps. TAHs can sustain patients for months as they await donor heart transplants. However, long-term survival on a TAH remains limited by risks of infection or device malfunction.

Destination Therapy with LVADs

As LVAD technology has advanced, these devices are now being routinely used not just as bridges to transplant butalso as destination therapy for patients who are not candidates for heart transplantation due to age, comorbidities or organ shortage. Long-term survival of several years supported by continuous-flow LVADs like the HeartMate II has demonstrated their efficacy as permanent lifelong therapy. Careful patient selection along with close multidisciplinary management is needed for optimal outcomes. However, advancements in device durability, portable batteries and infection prevention protocols continue expanding the pool of eligiblepatients who can benefit from long-term mechanical circulatory support.

Surgical Access and Implant Techniques

The surgical procedure required for VAD or TAH implantation involves gaining access to the heart, typically via a median sternotomy. Depending on the device, the inflow cannula is attached to either the left or right ventricle while the outflow graft connects to a major artery downstream like the aorta. Fine adjustments are made to pump speeds and settings based on surgical findings like ventricular dimensions and hemodynamics. Remote access ports are also placed and tunneled subcutaneously for external drivelines. Perioperative management focuses on optimizing right heart function and preventing complications like bleeding or infection. Short hospital stays are now common as physicians grow experienced with VAD/TAH procedures. Outpatient management involves monitoring implanted device parameters and coaching patients to safely adjust to device dependence.

Patient Selection and Outcomes

Careful pre-operative screening and evaluation is vital in selecting appropriate cardiac assist device candidates. Considerations include clinical status, organ function, rehabilitation potential, neurological status, psychosocial support system and device-related complications/risks. In the modern era, 1-year survival on left ventricular assist devices consistently exceeds 80% according to INTERMACS registry data. Long-term attrition is estimated at 10-15% annually thereafter. Emerging options like HeartMate 3 demonstrate improving 2-year survival over 90% and less incidents of major bleeding or strokes. Total artificial hearts have also shown 1-year survival exceeding 50% in transplant-eligible patients. Early intervention with LVADs or short-term VADs likewise portends better outcomes than delayed referral in advanced heart failure.

Future Directions

While great strides have been made, continued progress is still needed to optimize safety, durability and cost-effectiveness of long-term ventricular assist devices. Miniaturization of components, use of physiologic energy sources like epicardial blood pumps and development of partial support devices may expand eligibility and ease device management issues. Tissue engineering approaches aim to fabricate biologically based artificial hearts and vessels. Other frontiers include development of implant-free wireless extracorporeal ventricular assist devices and closed-loop control systems incorporating physiological feedback. Overall, mechanical circulatory support shows immense promise as an option for thousands of patients with advanced heart failure. Multidisciplinary

Explore more information on this topic, Please visit -

https://www.marketwebjournal.com/cardiac-assist-devices-market-size-and-trends-analysis/