TAVRs: The Minimally Invasive Alternative to Open-Heart Surgery

Illustration by Arushee Agrawal

Illustration by Arushee Agrawal

According to the World Health Organization (WHO), cardiovascular diseases are the primary global cause of death, as of late 2016. Fortunately, many cardiovascular conditions, such as congenital heart defects, coronary artery disease, and clogged, leaky, or stiff heart valves, can be remedied by open-heart surgery. During this procedure, the patient is anesthetized, and the surgeon opens the chest cavity. Then, the surgeon stops the patient’s heart and connects it to a heart-lung bypass machine, which repeatedly oxygenates and circulates the blood while removing carbon dioxide and waste products. Meanwhile, the surgeon could replace problematic valves with synthetic ones, or connect a vein to a clogged artery to circumvent blockage. With an average hospitalization time of 5 to 7 days, average recovery times of four to eight weeks, and high success rates, open-heart surgery remains an appealing solution to many cardiovascular problems. However, there is an extremely small chance of foreign objects being left in the heart, and of scar tissue restricting blood flow or causing chronic pain. More traditional risks of invasive surgery, such as infections or blood clots at incision sites, and reactions to anesthesia or sedatives, also apply. For older patients, who are more likely to have large calcium deposits that narrow the aortic valve, the recovery times for open-heart surgery to reduce aortic valve blockage (i.e. stenosis) can be especially taxing. Moreover, the risks mentioned above can sometimes prove fatal in older patients, necessitating a less invasive procedure with the same life-saving potential.
This is where the minimally-invasive, yet less widespread alternative, known as Transcatheter Aortic Valve Replacement (TAVR) or Implantation (TAVI), comes into play. The procedure involves sending a guide wire, followed by a prosthetic valve, through tiny incisions via one of three routes: the femoral artery in the groin (“transfemoral route”), the chest wall and the aorta (“transaortic route”), or the tip of the heart’s left ventricle (“transapical route”). A combination of fluoroscopy and echocardiography is used to direct the wire to the aortic valve. Once the wire is at the aortic valve, the prosthetic valve, consisting of a balloon-expandable metal alloy frame, bovine pericardial tissue, and fabric, is directed along the wire, onto the original aortic valve site, and expanded. The tiny incision made to access the artery can then be sutured and closed.
According to Krishna Mudimbi, a cardiac anesthesiologist at Medical City in Fort Worth, TX, recovery times for this procedure are generally shorter, with average hospitalization times of three to five days (five-to-seven-day average for open-heart surgery). Moreover, the chest cavity does not need to be opened, since the heart does not need to be connected to the heart-lung machine, which also shortens the recovery time. Sometimes, according to Dr. Mudimbi, TAVRs can even be performed under sedation alone, without general anesthetic, further shortening recovery times by reducing the amount of medicine to be flushed out of the patient’s system.
In summary, TAVRs constitute a relatively recent, minimally-invasive alternative to open-heart surgery, especially for older patients or for patients adversely affected by long recovery times. Soon, given the advantages mentioned above, the procedure might become more mainstream, as it could be used in patients who cannot physically afford open-heart surgery. Of course, medicine has undergone vast improvements since the times of the infamous barber-surgeons, and many procedures are now quicker and less invasive. Even so, modern surgical procedures are still being made less invasive to shorten recovery times and minimize the amount of healing needed. TAVR is a perfect symbol of the progress so far, and of the progress that will inevitably take place down the road.




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