Florida Hospital Pepin Heart Institute in Tampa is among the first in Florida to offer patients with non-valvular atrial fibrillation a first-of-its-kind, proven alternative to long-term warfarin therapy for stroke risk.
The Watchman Left Atrial Appendage Closure (LAAC) System – approved March 13, 2015, by the United States Food and Drug Administration – is a permanent, catheter-delivered heart implant designed to close the left atrial appendage (LAA).
The device is implanted at or slightly distal to the ostium of the LAA, which is believed to be the source of more than 90 percent of stroke-causing clots in patients with non-valvular atrial fibrillation (AF or AFib). The occlusion prevents migration of throm-bus, thereby reducing the risk of stroke. Most patients are able to discontinue the use of oral anticoagulants 45 days after implant.
“In appropriate AF patients, the Watchman device is equal to or better than blood thinners in reducing the risk of stroke and at the same time reduces the risk of bleeding associated with blood thinners,” says Kenneth Yamamura, M.D., an electrophysiologist who is one of only two physicians in Tampa specially trained to implant the Watchman device at Florida Hospital Pepin Heart Institute.
Clinical trials evaluating the Watchman LAAC have shown that it can reduce stroke risk by 36 percent and mortality at four years by 56 percent. “Over time it’s going to be even better,” says Dr. Yamamura. “If you figure you implant the device in a 65 year old who will live another 15 years, the reduction keeps getting more significant.”
The Centers for Medicare & Medicaid Services (CMS) pro-vides the following indications for Watchman implantation:
- CHADS2 score ≥ 2 or CHA2DS2-VASc score ≥ 3
- A formal shared decision making interaction with an indepen-dent non-interventional physician using an evidence-based decision tool on oral anticoagulation in patients with NVAF prior to LAAC. The shared decision making interaction must be documented in the medical record.
- Suitability for short-term warfarin but deemed unable to take long term oral anticoagulation following the conclusion of shared decision making as LAAC is only covered as a second-line therapy to oral anticoagulants.
Despite the proven efficacy of long-term anticoagulation therapy to reduce the rate of stroke or embolism in patients, about 40 percent of AF patients who are candidates for anticoagulation go untreated. Reasons for not tak-ing anticoagulation medication include concerns about the bleeding side effects and/or a desire to forgo the necessary life-style compromises – dietary restrictions and frequent monitoring. Other patients have contraindications that prevent long-term anticoagulation use.
“This highlights the need for additional treatment options,” says Dr. Yamamura.
He describes a 72-year-old female patient who after AF diagnosis was pre-scribed warfarin and had an ablation that achieved normal heart rhythm. Then she had a life-threatening episode of bleeding that required five liters of blood, so an-ticoagulation therapy was discontinued. “Even though she had just one AF epi-sode, she may still be at risk of stroke,” he says. “I think she is a perfect candidate” for the Watchman device.
Many AF patients cannot tolerate long-term anticoagulation therapy because of comorbidities with symptomatic bleeding. For example, “there is a large population, especially here in Tampa, that is suffering from digestive disorders – such as diverticulitis and other causes of intestinal bleeding –and at the same time has AFib,” says interventional cardiologist Asad Sawar, M.D., who also performs the Watchman procedure at Florida Hospital Pepin Heart Institute.
He and Dr. Yamamura have assumed the lead in performing the Watchman LLAC implant. The first patients at Florida Hos-pital Pepin Heart Institute are scheduled for the procedure this month.
Dr. Yamamura suspects that future trials may result in a loosening of the requirement for warfarin after Watchman implanta-tion. The medication is taken to diminish the slight risk of blood clot formation on the Watchman device. He says a small study indicated no difference in outcomes among those taking warfarin and those who did not.
Despite the strong evidence of medical benefit, physicians are not likely to recommend Watchman implantation over oral anticoagulation as a first course for AF treatment. If, on the other hand, “a patient with AFib is not able to use blood thinners then the Watchman is the way to go,” says Dr. Sawar.
The challenge for the future is that as the population ages the risk of stroke increases and treatment using blood thinners de-creases because of the risk of falls and injury. “To have this device implanted in already is a benefit. As the population ages, I think it’s a huge benefit moving forward,” says Dr. Yamamura.
Safety and Efficacy of Watchman Implantation
Implantation of the Watchman device is an hour-long procedure under anesthesia. The device is guided from the femoral vein in the upper leg into the heart using a delivery catheter. The implant is introduced into the right atrium and passed into the left atrium through a patent foramen ovale in the atrial septum. The Watchman is then fed through the delivery catheter to the LAA, where it opens like an umbrella and is permanently affixed. Once in place, a thin layer of tissue grows over the Watchman device in about 45 days, permanently sealing off the LAA.
As with any surgical procedure, the Watchman implant has its risks. Acute procedural complications are mainly related to transseptal puncture and device implantation. They include air embolism, pericardial effusions/cardiac tamponade and device embolization.
Risks have been greatly reduced over time as a result of numerous technical and procedural enhancements. For example, transesophageal echocardiography guidance and pressure monitoring help ensure a safe transseptal puncture before advancing the sheath.
Extended follow-up trial results indicate hazard ratios for the composite endpoint of major bleeding, pericardial effusion and device embolization dropping from 2.85 at the original 600-patient-year follow-up to 1.53 at 1,500 patient-years.
“Another important part of Watchman trials is that strokes occurring soon after the procedure were minimal compared to the control group whose strokes were huge,” Dr. Yamamura says. To prevent the minimal risk of thrombus, patients take aspirin and warfarin for the first 45 days after Watchman implantation. This is followed by clopidogrel and aspirin for six months.
“Here at Florida Hospital, we have had the advanced training, we have experience in transseptal puncture and structural heart interventions and we have the necessary experience in managing and preventing complications to minimize the risks,” says Dr. Sawar.
“As an electrophysiologist, I perform multiple ablations a week that take place in the left transseptal junction. Because I deal with this region on a daily basis, I am familiar with it,” Dr. Yamamura says.
AFib and Stroke
Non-valvular AF is the most common sustained cardiac arrhythmia, currently affecting 1-2 percent of the general popula-tion, or more than five million Americans. Prevalence increases with age.
AFib is caused by chaotic electrical signals that make the upper chambers of the heart (the atria) quiver instead of contracting properly. During AFib blood pools in the atria, which can allow a clot to form. If a blood clot breaks free, it can enter the blood-stream and cause a stroke. People with AFib have a stroke risk that is five times higher than people who do not have AFib.
“Stroke from AF tends to be disabling and potentially fatal, because the left atrial appendage can form a large blood clot that ultimately blocks blood vessels in the brain,” says Dr. Yamamura.
“The clot is less likely to cause a TIA (transient ischemic attack) and more likely to be life threatening.”
In fact, 70 percent of AF-related strokes result in death or permanent disability.
Expanding AF Treatment Options
“We have extensive experience and expertise in treating AFib, and the Watchman device offers another option in our integrated and comprehensive approach to therapy,” says Dr. Sawar.
Standard AF treatment encompasses either rate control and/or rhythm control strategies, accompanied by antithrombotic therapy based on an individual’s stroke risk and ongoing monitoring inmost cases. Medical treatment should be complemented by healthy adjustments to one’s lifestyle, particularly in terms of proper diet and body weight as well as appropriate amounts of sleep.
Pharmacological agents for slowing the heart rate, such as Þ-blockers, are currently recommended as the first course of therapy. Returning the heart to normal sinus rhythm is typically achieved using antiarrhythmic drugs, electrical cardioversion or ablation therapy. While rate and rhythm control therapies relieve AF symptoms, such as palpitations, shortness of breath and fatigue, they don’t reliably prevent thromboembolic events.
The vitamin-K-antagonist warfarin is the most commonly pre-scribed medication to prevent strokes. In use for more than 50 years, warfarin has been shown to prevent two out of three strokes compared to no treatment in patients with AF.
Newer anticoagulants – dabigatran, rivaroxaban, apixaban and clopidogrel – are just as effective as warfarin in preventing thromboembolic events. In addition, they have the advantage of eliminating the dietary concerns and the need for regular blood monitoring that come with warfarin. While major bleeding and associated complications remain with the newer medications, they are somewhat less than with warfarin.
In most cases, says Dr. Sawar, the risk of bleeding associated with anticoagulation use is minor and presents as bruising or minor nosebleeds. About 1-2 percent of people on anticoagula-tion will develop more serious bleeding that may require a blood transfusion and the interruption of blood-thinning medication.
The HAS-BLED bleeding-risk scoring system assesses the one-year risk of major bleeding associated with oral anticoagulation:
H – Hypertension, with uncontrolled blood pressure more than 160 mmHg.
A – Abnormal kidney function, including patients who have had a transplant.
- Abnormal liver function.
S – Stroke, including TIA.
B – Bleeding that has been serious.
L – Labile INRs (international normalized ratios) that range from 2.0 to 3.0 in those taking warfarin. In people who are not taking a blood thinner, blood clots with INR of about 1.0. To reduce the risk of a stroke in atrial fibrillation the blood needs to be 2-3 times thinner than normal.
E – Elderly, age 65 years and older.
D – Drug use, including regular use of aspirin or pain killers.
- Alcohol intake above recommended daily amount.
Each factor is assigned one point, including a point for each of the two factors in A and D, for a total maximum HAS-BLED score of nine. Patients who have a high risk of bleeding (score of three or greater) and are taking anticoagulation should undergo regular clinical review.
The scoring system also is able to discriminate the risk for intra-cranial hemorrhage (ICH), a lethal bleeding side effect of antico-agulants and the cause of up to 10 percent of strokes.
Most recent studies show the risk of ICH in patients taking anticoagulation medication is about 0.2-0.4 percent per year or slightly higher. While not trivial, this is substantially lower than the 5 percent annual risk of ischemic stroke in the vast major-ity of AF patients who are not anticoagulated. Studies also have shown that the risk of ICH with the newer oral anticoagulants may be less than half of that with warfarin.
“To have a device that’s capable of preventing not only the embolic stroke but hemorrhagic stroke by eliminating the need for warfarin, is a huge step in our treatment of AF,” says Dr. Yama-mura.
Increasing Stroke Awareness
A collaborative survey between the National Stroke Association, Heart Rhythm Society and Boehringer Ingelheim uncovered a critical need to improve communication and education about the link between atrial fibrillation and the devastating impact of stroke.
Dr. Sawar agrees, “We need to get the word out, so people better understand their risks of stroke.”
The medical community can help increase awareness of the risk factors, which include age over 60, high blood pressure, diabetes, excess weight and existing heart disease. Sleep apnea is another. While not completely understood, there is increasing recognition of the influence of long-term, untreated sleep apnea on a number of impairments, including cardiovascular conditions like high blood pressure, stroke and AFib.
Gender is another risk factor. “We probably need to be emphasize blood thinners and the Watchman implant for women, because we know they are at higher risk of stroke due to AF than men,” says Dr. Yamamura.
“We’re still appropriately treating only about 60 percent of AFib patients with anticoagulation. If there is one clear mes-sage to convey it is – whether we treat the patient with the Watchman device or anticoagulation, physicians need to do a better job of treating patients with AF.”
“Among patients with AF who are not on anticoagulation therapy, some will have a stroke during the early monitoring period after diagnosis. A majority will have a stroke within a few years of diagnosis. A small percent will not have a stroke for 10 to 15 years after. Based on the annual 5 percent rate for stroke among untreated AF patients, within the next 20 years almost all will have a stroke,” says Dr. Sawar.
In other words, he adds: “Those with atrial fibrillation who are not taking blood thinners are a time bomb. Their 5 percent risk of stroke is much greater than their risk of getting into a car wreck.”
The challenge facing physicians is that patients with AF of-ten don’t experience symptoms. Patients need to understand that AFib symptoms are subtle and may include paroxysmal or persistent fluttering or thumping in the chest, dizziness and shortness of breath.
AFib is diagnosed by reviewing medical and family histories, completing a physical exam and conducting diagnostic tests and procedures. If someone has AFib, it is important for him or her to discuss with a physician treatment options that can help reduce the risk of stroke.
Advancing Cardiovascular Medicine
Florida Health Pepin Heart Institute is on the cutting edge of cardiovascular medicine in the Tampa Bay area.
Dr. Sawar list a number of firsts:
- First in Florida to introduce the AngioVac System, therapy for patients suffering from illiofemoral deep-vein thrombosis and massive swelling in the legs.
- First in Tampa Bay to offer subcutaneous implantable defibrillators for the treatment of ventricular tachyarrhythmias.
- First south of Boston to establish a formalized pulmonary embolism response team.
“These are things I have been personally involved in,” he says. “They are in addition to all the other things that all the other Pepin Heart Institute doctors are doing.”
For instance, cardiologist Charles Lambert, M.D., medical director of Florida Hospital Pepin Heart Institute, is leading an innovative Parachute clinical research trial on a therapeutic implant for congestive heart failure patients who have no viable treatment options. It is one of 12 active clinical research trials at Pepin Heart Institute that enable patients to receive leading-edge cardiovascular medicine without leaving Tampa Bay.
“We are excited to offer this one-of-a-kind treatment at Florida Hospital Pepin Heart Institute,” said Thomas Nicosia, Assistant Vice President of Cardiovascular Services at Florida Hospital Tampa. “For more than 20 years, Pepin Heart has been at the forefront of innovative cardiovascular care. The Watchman is an-other example of how we’re bringing the latest technology, procedures, and expertise to the Tampa Bay community.”
By Heidi Ketler
For more information about Watchman device implantation, comprehensive AFib treatment, clinical trials or other cardiovascular services at Florida Hospital Pepin Heart Institute, call (813) 554-3278.