Category: Latest Articles

Left Ventricular Assist Device and How it works

What is a LVAD?

A left ventricular assist device (LVAD) is a mechanical pump implanted inside a patient’s chest to help the heart to pump blood around the body. It helps to bear the stress of the heart by circulating the blood to the rest of the body, allowing the heart to rest while other organ functions are sustained by the pump. The LVAD helps patients with advanced heart failure by relieving their symptoms such as shortness of breath and weakness, improving their exercise capacity and prolonging their survival.

How does the LVAD work?

The LVAD is implanted via an open heart surgery, with one end attached to the tip of the left ventricle (main pumping chamber of the heart) and the other end to the aorta (main artery of the body). Blood is pumped out of the left ventricle into the aorta by the LVAD. An insulated electrical cable (driveline) passes from the device, through the skin, to connect the pump to an external controller and electrical power source (two battery packs) outside of the patient’s body. The controller and battery packs are usually carried in a pouch that is slung on the shoulder or worn around the waist. The batteries are rechargeable.

Which patients require LVAD?

Patients with advanced heart failure have a poor quality of life and a one-year survival rate of less than 50%. Those who should consider an LVAD surgery include patients who have severely impaired left heart function AND:
a. have frequent disabling heart failure symptoms like breathlessness at rest or on mild exertion despite being treated with oral medications, OR
b. have frequent hospital admissions for heart failure, OR
c. have critically low blood pressure and require intravenous medications or mechanical devices to boost the blood pressure. These patients are usually confined to the Intensive Care Units (ICUs).

After a successful LVAD implantation, majority of patients experience markedly improved exercise capacity and reduced hospital readmissions. In Singapore, the 5-year survival rate of patients on LVAD support is more than 80%.
The LVAD can be implanted to temporarily support patients while they await a heart transplant (Bridge-to-Transplant) or as a permanent support (Destination Therapy).

Consult your cardiologist about LVAD if you continue to experience heart failure symptoms not controlled by your medications.

August 26, 2019

Device Closure of PFO in Scuba divers with Decompression sickness

Suba diving is a popular sport in many countries. While the general risk of death or major injury during scuba diving is small (<0.001% per dive), one of the notable risks include decompression sickness.

Decompression sickness, also known as divers’ disease, is caused by nitrogen bubbles forming in the diver’s tissues during his ascent. These bubbles can form in or migrate to any part of the body, causing varied levels of symptoms, ranging from simple symptoms involving skin rashes and pain in the joints to more serious symptoms which can lead to paralysis or even death when the other organs such as the central nervous system (including brain), are involved.

The connection between Patent Foramen Ovale (PFO) and decompression sickness was first described in the 1980s. Foramen ovale is a hole between the top chambers of the heart in the fetus which is normally closed by a flap within the first breaths at birth. However, in about 27% of the adults, the flap does not seal the gap causing it to remain open (patent), hence allowing blood to travel from the right to the left heart chambers during occasions when the chest pressure is raised. In the event of decompression sickness in divers, the bubbles in the venous system can by pass the lungs where they were supposed to be filtered out, and travel directly to the arterial system through the PFO and left side of the heart. The arterial system includes arteries to the brain, spinal cord and heart. Blood formation in the arterial system also known as arterial gas embolism, is far more dangerous as it can result in blockage in the blood supply to the brain or spinal cord, leading to stroke or paralysis.

Currently, in most countries, routine screening for PFO in divers is not recommended. Suggested recommendations for divers with diagnosed PFO and a history of decompression sickness include cessation of diving, a conservative approach to diving, and PFO closure.

Transcatheter Device Closure of the PFO is the implantation of an occluder device across the PFO through a catheter (plastic tube) inserted via the leg vein in the groin. The device acts like a double-sided umbrella that opens on each side of the atrial wall between the top chambers of the heart to seal the PFO. This helps to eliminate the chance of arterial embolization, allowing the diver to return to unrestricted diving. It is a minimally invasive procedure, which can be performed with mild sedation, and takes less than one hour, with one night stay in the hospital. Most patients can return to normal activity in two days, but they must take anti-coagulation medication and blood thinners for three to six months. Other restrictions include: no elective dental care (such as cleanings) for three months, no contact sports for three months, and no heavy lifting for one week. After implantation, divers must abstain from the sport for three to six months.

Before proceeding to do the transcatheter PFO closure, the patient has to undergo a transthoracic echocardiogram or a heart scan, with an ‘agitated bubble saline study’ to see if there is any possible sign of PFO. After which, a transoesophageal echocardiogram (similar to a scope), will be performed to help confirm the diagnosis.

Although there are no consensus criteria for PFO closure in divers currently, several studies have established that the incidence of PFO is two to six times greater in divers who experience a neurological decompression; and that catheter-based PFO closure is shown to lead to complete elimination of arterial bubbles after simulated dives, suggesting that PFO closure in continuing divers have a relevance in preventing symptomatic (major decompression sickness) and asymptomatic (ischaemic brain lesions) neurological events. There is a small risk of complications with PFO closure which should be discussed with the cardiologist.

Sources:

http://www.alertdiver.com/294

https://heart.bmj.com/content/97/23/1932.long

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6220018/

https://en.wikipedia.org/wiki/Decompression_sickness

Primary Transcatheter Patent Foramen Ovale Closure Is Effective in Improving Migraine in Patients With High-Risk Anatomic and Functional Characteristics for Paradoxical Embolism

https://link.springer.com/article/10.1007/s12471-018-1153-x

March 26, 2019

TAVI/ TAVR now shown to be Equal or Better than Open Heart Surgery

During the latest American College of Cardiology (ACC) 68th Annual Scientific Session held in New Orleans, LA, on March 2019, data presented demonstrated strong evidence that Transcatheter Aortic Valve Implantation (TAVI/ TAVR) is non-inferior or even better than open-heart surgery for aortic valve replacement for low-risk patients with aortic stenosis. Two studies, PARTNER 3 and the Evolut TAVR in Low-Risk Patients trial were presented.

The PARTNER 3 trial exceeded noninferiority expectations, with investigators reporting that treatment with the balloon-expandable Sapien 3 transcatheter heart valve (Edwards Lifesciences) was better than surgery for the prevention of death, stroke, and rehospitalization at 1 year, the study’s primary endpoint.

In the Evolut Low-Risk trial, which tested the self-expanding CoreValve, Evolut R, and Evolut PRO (Medtronic) valves in a low-risk patient population, the 24-month estimated incidence of death or disabling stroke was similar in the TAVR and surgical arms, meeting the definition of statistical noninferiority but not superiority.

Michael Reardon, MD (Houston Methodist DeBakey Heart and Vascular Center, TX), the co-principal investigator of the Evolut Low-Risk TAVR trial and cardiac surgeon, said TAVI/ TAVR should be the preferred strategy across the entire risk spectrum of patients. When discussing treatment options in low-risk patients with severe aortic stenosis, unless he mentions the benefits of TAVI/ TAVR, “I have not truly given informed consent,” he added.

The results of the trials were said to change the landscape of treatment for severe aortic stenosis.

From a patient’s perspective, only one-third of the TAVR patients from the trial underwent general anesthesia and very few were taken to the intensive care unit after the procedure. TAVR patients were hospitalized for shorter periods after valve replacement and the vast majority were discharged home or to self-care. “In the first 30 days, they have almost complete recovery to normal functional status,” said Martin Leon, MD (NewYork-Presbyterian/Columbia University Irving Medical Center, New York, NY), one of the lead PARTNER 3 investigators. All of this, said Leon, “is very powerful from the standpoint of a new therapy for low-risk patients.”

“If you had a TAVR, you’re going to be out of the hospital in less than half the time as surgery patients and more likely to go directly home,” said Reardon. “The hemodynamics are what we’ve come to see in all the randomized trials with the supra-annular valve, that is single-digit mean gradients and [effective orifice areas] that are 2 [cm2] or above.”

Both trials are now published in the New England Journal of Medicine following an embargo break ahead of the ACC presentation.

The Heart and Vascular Centre performs TAVI with Edwards Sapien S3 valve, Corevalve Evolut R and Evolut Pro, along with a FDA approved Cerebral Protection Device for stroke prevention during the procedure.

Sources:

https://www.tctmd.com/news-acc-2019-low-risk-trials-cement-role-tavr-alongside-or-place-surgery

ACC 2019: Evolut TAVI as good as surgery for low-risk patients

November 6, 2018

Is your job stress bad for your heart?

By Dr Paul Chiam
Published on Ezyhealth on April 2015

Work stress can do a real job on your ticker

It is commonly accepted that work stress can affect our cardiovascular health. You’re probably familiar with the phrase “worked to death”!

Various kinds of jobs create different types of stress, and whether the stress becomes harmful depends on the individual – some people cope much better than others.

Some individuals even thrive as the stress drives them to work harder and improve work performance! So is job stress actually bad for your heart?

What is a stressful job?

Most studies concur that jobs become stressful in situations where the worker feels that he or she has little or no control. Let’s say you have a highly demanding job. If you have minimal power to make decisions about your daily tasks, that makes it a lot more stressful than if you have some control. If you love your job and enjoy what you’re doing, then putting in long hours is not going to have too much impact.

How stressful a job is also depends on the personality of the individual and his co-workers. Persons with hostile personalities face more job stress and are at higher risk of a cardiovascular event. Jobs that require sudden intense bursts such as firefighters may also place more stress on the workers.

The Stats on Job Stress and Your Heart

A large British study of over 10000 white collar workers over a 12-year period found that people who felt stressed at work were 68% more likely to die of heart disease, suffer a non-fatal heart attack or have exertional chest pain (angina).
Another British study of over 6000 civil servants found that overtime work of three to four hours a day was associated with a 1.5 times increased risk of heart disease, independent of other risk factors.
Researchers in South Korea found that increasing numbers of hours worked per week correlated with increased heart disease. Compared to those who worked 31 to 40 hours a week, workers putting in 61 to 70 hours a week had a 42% increased likelihood of developing coronary heart disease; those working 71 to 80 hours a week had a 63% increased likelihood; while those working more than 80 hours a week had a 94% increased likelihood.

Although these statistics look alarming, they must be considered in the context of other risk factors that can contribute to heart disease. In an analysis of 13 studies pooled together, job strain was found to contribute to 3.4% of heart attacks; conversely, smoking alone accounted for 36% and physical inactivity for 12% of heart attacks! So though job stress can indeed increase heart disease, the overall burden on heart disease is small.

How does one’s job affect the heart?

Job stress can affect the heart arteries directly by causing mild vasoconstriction (artery narrowing). Stress causes blood pressure to rise, and blood platelets (a group of cells that promote blood clotting) to become stickier. These changes have been associated with increased risk of heart attacks.

Job stress and long work hours can also result in poor sleep, a lack of physical exercise, increased smoking (to cope with the stress!) and in some people, heavy alcohol intake and binge eating, resulting in weight gain (which predisposes them to diabetes and heart disease).

Working at odd hours and shift work can also result in sleep deprivation. This can lead to high blood pressure, weight gain and increased levels of a stress hormone called cortisol (this hormone increases blood pressure and blood sugar), raising the risk of heart disease.

What can one do to reduce job stress?

It may not always be possible to reduce job stress in a fast-paced competitive society like ours, and it certainly is not an easy thing to do in any case. However, there are some things we can do to help mitigate job stress.

Regular exercise – Take short breaks where possible and move around. Even walking around is better than sitting at the desk all day. Schedule regular exercise on a weekly basis, ideally at least three times a week for 20 to 30 minutes each time. Exercise helps take our minds off work.
Relax – Learning how to relax can be beneficial to one’s overall health. Picking up a new hobby takes the mind off work and helps relaxation.

In many situations, we cannot reduce the job stress that we face. We can help ourselves, however, by getting regular exercise, not smoking, adhering to a sensible diet, and screening for and controlling cardiovascular risk factors for heart disease such as diabetes, high blood pressure and high cholesterol.

November 6, 2018

Screening for Cardiovascular Diseases

Screening for cardiovascular diseases

By Dr Paul Chiam
Published on Medical Grapevine on October 2015

The aims of cardiovascular screening are to identify cardiac or vascular disease and detect cardiovascular risk factors in asymptomatic or “well” patients.

Screening starts with a thorough history and physical examination, and simple laboratory investigations. Other tests may also be performed when necessary according to the patient’s risk profile.

The tests that we choose should be cost effective, reproducible and accurate, and that the diseases being screened should be serious with early detection leading to a better outcome.

However as no test is 100% sensitive nor specific, false positive results may paradoxically increase costs due to the need for further tests and create unnecessary anxiety, whereas false negative results may confer a false sense of security to the patient.

Thus screening should be evidence based and should result in a change in lifestyle leading to improved outcomes.

Screening for cardiovascular risk factors and cardiovascular disease

The screening usually starts with a detailed history and physical examination. They are part of the initial consultation, and do not involve additional cost or risk to the patient. A cardiovascular risk profile (eg 10-year risk of cardiovascular event – high, moderate, low risk) can be estimated using the Framingham risk score calculator (cvdrisk.nhlbi.nih.gov) or the HeartScore risk calculator (escol.escardio.org/Heartscore/calc.aspx?model=europelow). These have been shown to predict likelihood of future events and can serve as an impetus for behavioural change.

Subsequent tests such as the electrocardiogram (ECG) and chest x-ray (CXR) can help further stratify the risk profile of the patient. Apart from the ECG and CXR, the fasting glucose and fasting lipid profile are amongst the most useful screening tests. These tests, together with the office blood pressure, will detect the 3 common risk factors for cardiovascular disease as a significant proportion of the population may have silent diabetes mellitus, hypertension or dyslipidemia. Early detection and treatment (lifestyle or drugs) are likely to have an impact on future event rates as demonstrated in the primary prevention trials (eg. West of Scotland Coronary Prevention Study (WOSCOPS), Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) and STOP-NIDDM trial). WOSCOPs showed that primary prevention with pravastatin reduced myocardial infarction (MI) and death from cardiovascular causes in men with hypercholesterolemia compared to placebo. ASCOT showed that treatment of hypertension with amlodipine and perindopril significantly reduced all-cause and cardiovascular mortality and strokes. STOP-NIDDM demonstrated that arcarbose could reduce progression of impaired glucose tolerance to overt Type 2 diabetes as compared with placebo. More recently, a lifestyle-intervention program or metformin have been shown in a major study performed by the Diabetes Prevention Program Research Group to reduce the progression of glucose intolerance to overt diabetes.

The NCEP guidelines which are endorsed by the American Heart Association, recommends a fasting lipid profile in all adults aged 20 years or older, and if optimal, every 5 years subsequently. If the results are sub-optimal, the fasting lipid profile should be repeated at earlier intervals. At the same time, the fasting glucose level can also be performed. The Ministry of Health, Singapore strongly recommends a fasting lipid profile at age 40 years (or younger in those with comorbidities or family history).

Silent peripheral vascular disease has been shown to confer a poorer long term outcome as these patients usually have multiple risk factors and/or heart disease. Asking for a history of claudication and palpation of the foot pulses are simple and effective methods of screening for peripheral artery disease.

Use of stress testing and imaging in cardiovascular screening

The treadmill ECG stress test (TMX) is a test that can be easily performed and is most useful for patients in the moderate risk category with atypical chest pain or patients who have a high cardiovascular risk profile. With a sensitivity and specificity of 70% at best, the TMX is not useful in low risk patients as it does not alter the low pre-test probability of heart disease. However, most patients presenting for cardiovascular health screening would want a TMX performed. The main utility is that it has been shown that patients with a normal result and good exercise capacity (Bruce protocol stage 3 or more) have a good long term prognosis and a low yearly cardiovascular event rate.

More recently, the CT heart scan derived coronary calcium score has been shown to be a predictor of future cardiovascular events since the calcium score is a reflection of the coronary plaque burden. The calcium score has become recommended by certain scientific societies for use in cardiovascular screening, and when combined with the TMX, gives added prognostic value.

In contradistinction, the CT coronary angiography is not recommended for use in screening as it entails a higher radiation dose, a need for intravenous contrast administration and the possibility of false negative and false positive results due to the limitations in the technology.

In patients whom silent peripheral vascular (artery) disease is suspected, an ultrasound Doppler of the lower extremity arterial system is a test that is safe and easy to perform and is fairly accurate.

Screening in the endurance or competitive athlete

This group of patients often present for screening. One knows too well of the rare incidences when a seemingly fit and healthy athlete suddenly collapses and dies. Though it is a rare occurrence, it is shocking and devastating. Common causes of sudden death in young athletes would include cardiomyopathies (in particular, hypertrophic cardiomyopathy), long QT syndromes and other arrhythmic/ conduction disorders, congenital anomalous course of the coronary arteries and silent ischaemic heart disease.

In general, competitive and endurance athletes should have at least an ECG performed before embarking on such activities. In selected patients, a TMX and echocardiogram may also be considered.

Conclusion

Regular cardiovascular screening may identify risk factors and preventive measures such as adopting healthy lifestyle habits can be carried out to minimise subsequent disease. With early detection and proper medical treatment, cardiovascular disease can be treated or even prevented.

November 6, 2018

Hypertension in Seniors

Hypertension in Seniors – When your health comes under pressure

By Dr Paul Chiam
Published on Ezyhealth on September 2014

Hypertension, or simple high blood pressure, is a common condition that afflicts many people. The incidence rises with age and is increasingly common with an ageing population. Hypertension is diagnosed when a patient has two separate readings of blood pressure (BP) >140/90 mmHg.

Some patients experience high BP when in the doctor’s office whereas their BP is ‘normal’ at home. This condition is termed ‘white coat’ hypertension and can be picked up with a 24-hour ambulatory blood pressure monitoring (a small portable device easily available in a cardiologist’s office). Although this condition usually does not require treatment, there is some evidence that is it not as benign as previously thought, and close monitoring of the patient’s BP would be required.

Importance of Detection

Hypertension has no symptoms in the vast majority of patients. In rare cases, very high blood pressure can result in headaches (although most headaches are unrelated to the patient’s BP), shortness of breath and blurred vision. In most people, however, it is a ‘silent killer’. Long standing poorly controlled hypertension increases the stiffness of the blood vessels and causes damage to many organs. The heart has to pump harder against the higher presuure, placing greater stress on the heart muscles. Patients with hypertension are at increased risk of stroke, heart attack, heart failure, kidney damage and aortic aneurysm (enlargement of the aorta) that can lead to fatal rupture.

This makes it important to detect and treat patients, especially younger patients, to reduce the risk of such events. Even very elderly patients (>80 years old) benefit from treatment of hypertension as they experience less stroke and adverse cardiac events. Thus, treatment of hypertension would be beneficial in virtually all patients, regardless of age.

Causes

In the vast majority of patients with hypertension, no specific cause can be found (this is medically termed ‘essential’ hypertension). Usually many factors contribute to hypertension in such patients, including genetics (family history), lifestyle (sedentary lifestyle), stress (high stress environment), high salt diet etc.

In a few patients (usually the very young patients <35 years), an underlying disease may be the cause of hypertension. In this age group, investigations, including blood and urine tests, are performed to rule out an underlying disease. In older patients, particularly those >65 years, the commonest underlying cause, if any, is the narrowing of the blood vessel supplying the kidneys. In these rare cases, treatment of the underlying disease may ‘cure’ the patient of hypertension.

Treatment

Most patients with hypertension can satisfactorily control their BP with lifestyle modifications and drug therapy. A low salt diet, regular exercise, weight loss and reduced stress can lead to a lower BP. These may help patients with mild hypertension. However, as it is unlikely that BP would be reduced by more than 10mmHg on average even with these measures, most patients will still require some drug therapy.

There are four major classes of drugs available to treat hypertension and a variety of combinations could be used. In elderly patients, a thiazide diuretic (salt and water loss promoting drug) and a calcium channel blocker seem to be particularly effective in treating hypertension and also help reduce the risk of stroke. The ideal combination of drugs is best left to your primary physician as he/she will take into account other risk factors or presence of other diseases.

Recent guidelines from the American Joint National Committee on hypertension have recommended treating the elderly (>60 years old) to target BP of <150/90mmHg. In the younger patient, the goal is <140/90mmHg.

Screening and Prevention

The easiest way to detect hypertension is to go for regular screening with your physician. A simple office BP measurement is useful. In borderline cases, a more specialised 24-hour BP monitoring with a portable non-invasive device can be performed. Early detection and treatment can help to prevent many of the complications associated with hypertension. A healthy lifestyle (exercise, low salt fiet, maintaining an ideal weight, avoidance of prolonged stress, not smoking etc.) may reduce the likelihood of developing hypertension. If in doubt, see a doctor for a simple screen. This screen may ultimately save you from a more severe complication down the road.

Left Ventricular Assist Device and How it works

What is a LVAD?

How does the LVAD work?

Which patients require LVAD?

Device Closure of PFO in Scuba divers with Decompression sickness

TAVI/ TAVR now shown to be Equal or Better than Open Heart Surgery

Is your job stress bad for your heart?

Work stress can do a real job on your ticker

It is commonly accepted that work stress can affect our cardiovascular health. You’re probably familiar with the phrase “worked to death”!

Various kinds of jobs create different types of stress, and whether the stress becomes harmful depends on the individual – some people cope much better than others.

What is a stressful job?

The Stats on Job Stress and Your Heart

How does one’s job affect the heart?

What can one do to reduce job stress?

Screening for Cardiovascular Diseases

The aims of cardiovascular screening are to identify cardiac or vascular disease and detect cardiovascular risk factors in asymptomatic or “well” patients.

Screening starts with a thorough history and physical examination, and simple laboratory investigations. Other tests may also be performed when necessary according to the patient’s risk profile.

Screening for cardiovascular risk factors and cardiovascular disease

Use of stress testing and imaging in cardiovascular screening

Screening in the endurance or competitive athlete

Conclusion

Hypertension in Seniors

Importance of Detection

Causes

Treatment

Screening and Prevention

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