August 05, 2020 Cardiovascular Procedures & Probability of Stoke
The transcatheter aortic valve replacement (TAVR) has become an established and widely adopted treatment for patients who are under the risk of calcific aortic valve stenosis.
With the advancements in medical technology, the TAVR procedure has rapidly evolved in recent years. Earlier, TAVR was considered as an alternative to surgical aortic valve replacement (SAVR) for high-risk patients.
In further randomized control trials, TAVR emerged to be superior to SAVR. The wide adoption of TAVR across the continents in past few years, and increasing expectancy in coming years, is represented below:
Source: Journal of Thoracic Disease
Yet, further studies regarding the efficacy of TAVR procedure under challenging conditions still need to establish the TAVR technology as the default treatment option for all the patients with mild as well as severe aortic stenosis.
However, despite the improvements in TAVR device technology leading to its wide adoption, the rate of neurological events has been quite consistent for a considerable amount of time.
TAVR – Associated Challenge Despite Being the Highly Accepted Cardiac Procedure
In the face of the fact that TAVR procedure is far superior than SAVR, there is a challenge that has been showing up consistently. Studies have already revealed that the rate of strokes associated with TAVR is twice as much as the rate of stroke led by SAVR. According to the data received from PARTNER 1B study, the risk of neurological events with SAVR at 30 days and one year was found to be 2.4% and 4.3% respectively; while the rate of risk of stroke associated with TAVR at 30 days and one year was recorded to be 5.5% and 8.3%, respectively.
Presented below, is the graphical representation of stroke incidences led by TAVR reported by various studies.
Source: Journal of Geriatric Cardiology
Well, it is clear that TAVR patients are at higher risk of cerebral incidences as compared to SAVR patients. The most concerning fact is that the increasing adoption of TAVR procedure is certainly giving rise to the rate of cerebral events including stroke.
The increase in peri-procedural and post-procedural cerebrovascular events leading to high mortality rate has today become a serious complication and concern associated with TAVR, and other heart procedures as well, like atrial fibrillation (AF) ablation and structural heart procedures.
A stroke led by a cardiac procedure? Let’s dig deeper into this.
How is a Stroke Associated with a Cardiac Procedure?
Well, it is quite evident that all the body systems are interconnected, and work in conjunction with each other. The cardiovascular conditions affect brain health considerably, and so do cardiovascular procedures.
It is reported that the cardiovascular procedures cause up to 90% of brain lesions. In fact, the reported disabling stroke rates range from 1.6%-5.9% in TAVR trials.
The pathogenesis of stroke after TAVI is mostly embolic. The embolic brain lesions are led by the emboli that is ousted from the heart to the brain system. A minor stroke or a stroke caused due to esoteric reasons, can lead to irreversible neurological impairment, and cripple the physical and mental health of the patient for long term, or even for the lifetime. The loss of memory, inability to pay attention, lack of focus, and a confused state of mind are some of the neurocognitive issues that impact the quality of life.
What is an Emboli? How Does It Lead to Stroke?
Emboli is the large irregular mass of dystrophic calcification that disturbs normal valve function. It can be anything – a blood clot (thromboembolus), air bubble, or a debris of anything, that causes embolism. It requires a TAVR procedure to resume the normal functioning of the valve, by replacing it. TAVR is a less invasive option for those who cannot undergo open heart surgery or surgical aortic valve replacement (SAVR), due to some kind of complications.
During the TAVR procedure, the emboli material can get dislodged and can reach the three aortic branches led by the aortic arch. These three aortic branches that supply blood to the head, neck, and upper limbs may get obstructed by the emboli, causing a lesion leading to a stroke.
Perioperative & Postoperative Neurological Events in TAVR Patients
Several studies have been conducted to find the rate of perioperative & postoperative strokes led by TAVR.
Some studies indicate that the higher incidents of embolism occurred during the positioning of the valve. It is however, not clear, the positioning of which kind of valve leads to cerebral ischemic lesions.
A study conducted by the joint association of the Society of Thoracic Surgeons (STS), American College of Cardiology (ACC) and Transcatheter Valve Therapies (TVT) Registry, on 101430 TAVR patients for 5 years indicated a consistent trend of strokes occurring within 30 days after the TAVI procedure.
In a recent study, the post-operative neurological events after TAVR were evaluated, which indicated a steep spike in the rate of stroke and associated mortality, years after the procedure.
Apart from this, another study suggested that up to 84% patients suffered new silent ischemic embolic lesions post-TAVR.
The Increasing Prevalence of Protected Cardiac Intervention with CEP Devices
Brain damage as a repercussion of a cardiac procedure is a blighted consequence of a procedure that otherwise has been the most successful one. Brain damage at various degrees has serious implications on the physical and mental health. Several studies and research have been conducted to find out the most suitable technique of preventing such incidences by protecting the brain. And that is where the role of cerebral emboli protection (CEP) protection comes into light. These devices facilitate more precise valve implantation than sentinels, and have been quite successful in preventing cerebral infarcts.
The expected increase in adoption of these devices will certainly improve surgical outcomes to offer a better quality of life for patients, in the years to come.