Introduction
Ventricular assist devices (VADs) are becoming more and more popular due to the proportion of end-stage heart failure patients who qualify for a heart transplant exceeding the quantity of donor hearts. These tools may serve as a bridge to acceptance, a bridge to healing, or a bridge to running for office. Improving organ perfusion and function results in improved quality of life and survival, which is the primary benefit of mechanical circulatory support (MCS). Patients suffering from end-stage heart failure who are not suitable candidates for a heart transplant may also use the MCS as a destination treatment. It should be kept in mind that, even with the apparent advantages, there is a chance that VAD implantation might result in significant side effects such as bleeding, infection, arrhythmias, blood clots, and right ventricular failure.
What Is Mechanical Circulatory Support Devices?
In the short term, mechanical circulatory support devices enable cardiac recovery by restoring systemic perfusion. In the long run, however, MCS devices serve as durable support devices for patients with persistent heart failure. Individuals who suffer from advanced heart or pulmonary failure could require mechanical support to maintain enough blood flow from their hearts. Devices known as mechanical circulatory support (MCS) can replace or augment the function of the failing heart or lungs, either temporarily or permanently.
What Are the Types of Mechanical Circulatory Support Devices?
1. Ventricular Assist Devices
These gadgets replace one of the heart's ventricles in terms of functionality. They assist in pumping blood from the heart's chambers to the body, hence sustaining the heart.
These two kinds are:
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Left ventricular assist device (LVAD).
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Right ventricular assist device.
2. Total Artificial Heart (TAH)
In patients with end-stage heart failure, this device replaces the function of both ventricles.
The following can be differentiated based on the anticipated length of circulatory support:
1. Short-term (7 Days or Less) Circulatory Support
It is supplied by rotary pumps that enable the extracorporeal membrane oxygenation (ECMO) and ventricle (right or left) to operate.
2. Medium-term (Three Months to Seven Days) Circulatory Support
Certain centrifugal pumps and pulsatile pumps (POLCAS, ABIOMED) provide it.
3. Extended Circulation Assistance (Months or Years)
It is supplied by pulsatile flow or continuous flow left ventricular or biventricular assist devices (LVAD, BiVAD).
What Is the Need for a Mechanical Circulatory Support Device?
The rising prevalence and poor prognosis of heart failure (HF) have made it a more pressing clinical, financial, and social issue. Patients over 75 years of age had a 20 percent higher prevalence of symptomatic heart failure than those in the general population, which is 2 to 3 percent. Organ transplantation is the most successful way to treat end-stage heart failure; however, because there is a shortage of donors compared to transplant candidates, patients must be treated with alternative therapies to extend their lives and improve their quality of life. Mechanical circulatory support (MCS) devices are becoming more popular for the reasons listed above. Improved organ perfusion and function lead to better patient outcomes, including improved quality of life and prognosis. This is the main advantage of this approach. For individuals who are not suitable for a heart transplant, MCS can thus be utilized as a destination treatment.
What Are the Indications for Ventricular Assist Devices?
The use of VAD is classified as a class IIa destination treatment and a class I bridge to cardiac transplantation in the 2012 European Society of Cardiology recommendations for the management of acute and chronic heart failure. In reality, mechanical circulatory support is mostly utilized as a bridging therapy in patients who are actively waiting list candidates for heart transplantation.
When symptoms of a heart failure exacerbation remain unresolved for at least two months and are accompanied by two or more of the following, patients are eligible for VAD implantation even with effective medication and electrotherapy.
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Three or more episodes of heart failure aggravation that necessitated hospitalization in the previous 12 months.
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Spiroergometry revealed a significant reduction in maximum oxygen consumption (VO2 max < 12 ml/kg b.w./min) and a significant deterioration of left ventricular systolic function (LVEF < 25 percent).
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Impairment of liver and renal function brought on by developing right ventricular dysfunction and perfusion problems brought on by reduced cardiac output.
Important eligibility requirements for VAD implantation also include the following hemodynamic parameters:
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Pressure in the systolic artery is less than 80 mm Hg.
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Heart index less than 0.52 US gallon.
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Central venous pressure is more than 20 mm Hg.
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Pneumatic wedge pressure greater than 20 mm Hg.
Irreversible damage to the central nervous system and widespread neoplastic disorders are absolute contraindications for VAD implantation. Infections that are resistant to therapy and serious organ damage are examples of relative contraindications.
What Are the Complications After VAD (Ventricular Assist Devices) Implantation?
After VAD implantation, the following early and late postoperative problems might happen:
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Right ventricular insufficiency, arrhythmias, severe bleeding, local infections, and cardiovascular events are the primary early consequences.
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Over an extended period, thrombi, device-related infections, and generalized infections predominate.
Following VAD implantation, the kind of device, length of support, and clinical state of the patient are the main factors influencing the likelihood of problems.
Hemorrhagic Complication
One of the most frequent side effects following VAD implantation is perioperative hemorrhage. Fifteen to thirty percent of individuals who have VADs implanted experience massive bleeding; this is typically due to a malfunction in the liver's ability to produce enough coagulation factors. In this patient population, iatrogenic bleeding linked to antiplatelet medications and vitamin K antagonist usage is a somewhat typical occurrence.
Cardiovascular Complication
Vascular access or direct heart damage may be linked to cardiovascular issues resulting from MCS devices. The two most common direct cardiac consequences are valve damage and chamber perforation (caused by cannulas inserted into the atrium), which can lead to cardiac tamponade, pericardial effusion, and shunting.
Cannulated artery dissection and distal limb ischemia are examples of vascular problems. The size of the cannula, the patient's vasculature, the promptness of deployment, and the concurrent use of vasopressors all influence the risk of distal limb ischemia. Amputation may be necessary in severe cases of limb ischemia. Large femoral artery cannulas used in extracorporeal membrane oxygenation make patients particularly vulnerable. To assist in lowering the occurrence of this life-threatening complication, approaches including distal limb perfusion and near-infrared spectroscopy monitoring are necessary.
Conclusion
The increasing number of individuals with severe heart failure receiving MCS treatment. When the heart is not functioning at its best, mechanical circulatory support (MCS) device aids in its function; managing patients receiving mechanical circulatory support involves several facets, including preventing problems, offering psychological and behavioral treatment, and providing technical, microbiological, and hematological oversight.
