Wednesday, April 20, 2011

Mitral Valve Repair Without Open Surgery – Exciting Development in Medical Devices

The mitral valve separates the heart’s left atrium from the left ventricle. When the ventricle contracts to send blood to the aorta and out to the body, the mitral valve closes to prevent blood rushing backward into the atrium and back to the lungs. The mitral valve can become stiff and tight, called stenosis or it can become unable to close tightly, called regurgitation. Once the regurgitation becomes sufficiently severe to cause heart failure, the death rate reaches about 5% per year. Most such individuals are referred for cardiac surgery to either try to repair the valve, replace the valve or do a procedure that in effect lessens the amount of regurgitation without actually replacing the valve. The latter procedure, although not curative, can be quite successful and alleviate the heart failure and the symptoms leading to a longer and better quality life.

A new procedure has now been reported in the New England Journal of Medicine, April 14, 2011 that does not use open surgery to repair the mitral valve leak. The process is to insert a catheter via the large femoral vein in the groin and pass it up to the heart. From the right atrium it crosses over to the left atrium and then is positioned at the opening of the mitral valve. This mechanical device, manufactured by Abbott Vascular, is able to grasp the two sides of the mitral valve and clip the two leaflets together. It does not create a tight seal but in most cases can markedly reduce the amount of regurgitant flow back into the atrium.

The study randomly allocated patients with grade 3+ or 4+ (i.e., serious) mitral valve dysfunction to either the customary open repair or replacement (the specific procedure at the surgeon’s discretion based on the valve status) or to have a percutaneous repair done with the new device. The study endpoints were freedom from death, freedom from surgery for mitral valve dysfunction and freedom from grade 3+ or 4+ regurgitation at the end of 12 months. The primary safety end point was freedom from major complications during the 30 days post procedure.

The study ws performed at 37 institutions in the United States and Canada. 279 patients were randomized with a 2:1 ratio of percutaneous vs. open procedures. 21 patients withdrew consent before the procedure was done, leaving 258 treated patients.

After the procedure, 41 of 178 (23%) patients who had the percutaneous procedure still had grade 3+ or 4+ regurgitation and were therefore referred for open surgery. Among those 80 patients who initially had open surgery, all had less that 3+ regurgitation after the procedure. By the 12 month end of study time, the composite of freedom from death, from surgery or from grade 3+ or 4+ valve dysfunction for all randomized patients were 55% vs. 73%. If one looks only at those who actually were treated per the protocol (i.e., did not exclude themselves, etc) then the rates were 72% vs. 88%. As to safety, the rates of major adverse events (most often the need for transfusion) as of 30 days were 15% vs. 48%. Quality of life improved in both groups of patients over the 12 months although there was a decrease at 30 days for the open surgery patients.

What these results suggest is that open surgery is more likely to greatly relieve the mitral regurgitation than will the percutaneous catheter procedure. However, the percutaneous procedure is safer, requires less time in the hospital, and is associated with improved quality of life and improved ventricular function from baseline. Many patients might therefore decide to choose the percutaneous catheter-based procedure on the grounds that it greatly relieves the problem in almost three quarters of the patients, is less invasive and is safer than surgery. Then if that individual patient was not among the success stories, he or she can choose to have the follow-up open surgery.

Further, although not mentioned in this article, there are patients who simply cannot tolerate open surgery for any number of reasons who might still be able to undergo the catheter-based procedure. This might then open up an option for repair not otherwise available today with open surgery. Not discussed in the article was cost. This might become a deciding factor as well once the procedure is on the market.

In an accompanying editorial, Otto and Verrier suggest that the decision on surgery (and which surgical procedure) or one of a number of catheter-based procedures (assuming logically that others will undoubtedly arrive soon) should rest on the advice of not one physician but the joint opinion of a multi-disciplinary team of, at least, a nonprocedural valve-disease specialist, and interventionalist cardiologist and a cardiac surgeon, each with substantial expertise in mitral valve disease. To this team I would add the patient’s primary care physician and principal cardiologist – both of whom will have known the patient and his or her overall health and family situation over the years. The other addition to the team is the patient --whose opinions should be incorporated from the beginning of the evaluation and advice process.

Monday, April 18, 2011

Ultraprocessed Foods Lead to Chronic Illnesses

Much of today’s foods are “ultraprocessed,” lead to obesity and its ultimate diseases such as diabetes, coronary artery disease, hypertension, many cancers and worsening of diseases such as osteoarthritis.

Ultraprocessed foods originate from just a few grains, namely corn, wheat and soy but these then undergo extensive chemical and mechanical manipulation resulting in compounds that humans have never eaten before. Just look at the ingredients list on many store products and notice first how many ingredients are listed and second how few of them you recognize. Further they are concentrated as to sugars, salt and calories while deficient or totally lacking in the fiber, micronutrients and phytochemicals found in fresh or frozen grains, vegetables fruits and unadulterated meats and fish.

David Ludwig MD, PhD of Boston Children’s Hospital wrote a cogent article on ultraprocessed foods in the April 6, 2011 edition of the Journal of the American Medical Association and upon which the proceeding was based. He explains that there have been three major breakthroughs in food technology. The first came perhaps 2 million years ago with the development of stone tools and the use of fire for cooking. This allowed the human who did not have the running speed of large carnivores nor the digestive tract attributes of herbivores like cattle and sheep to expand his diet. The second big technology breakthrough was domestication of grains – agriculture. This led to civilization in the sense of larger more stable communities because domesticated grains such as wheat and corn greatly increased calories available and no longer required migration to hunt or gather. He makes the interesting observation that human stature dropped a few inches with this change because grains carry fewer micronutrients and protein per gram than do animal meats and nuts.

The industrial Revolution was the third breakthrough technology which led to refined flours and concentrated sugars along with grain-fed rather than grass fed cattle, sheep and hogs. Such animals are heavy with saturated fats although their protein content and ready availability has resulted in a return of greater stature in recent generations. More recently have come ultraprocessed foods.

These ultraprocessed foods are high in calories from sugars and fats – often hydrogenated and trans fats – yet low in micronutrients. They are found in supermarkets’ “middle aisles” as processed foods such as cereal with added sugar, cheese “spreads”, “macaroni and cheese,” soups high in salts and calories, “sticky buns,” and of course sugared sodas. And ultraprocessed foods are readily available in many fast food outlets where a muffin may have 400 calories with high contents of sugars and saturated fats. A bacon cheeseburger, large fries and large soda can contain well more than one half of a day’s caloric needs yet be deficient in nutrients.

Ludwig concludes with “the problem is the creation of a dietary pattern based on factory-made, durable, hyper-palatable, aggressively marketed, ready-to-eat or heat foodstuffs composed of inexpensive, highly processed ingredients and additives. Reducing the burden of obesity-related chronic disease requires a more appropriate use of technology that is guided by public health rather than short-term economic benefit.”

What can we do? We need to cut back on the ingestion of these ultraprocessed foods. But this will not be easy. For this to work I believe we need incentives. After all, that bacon cheese burger tastes good – sugar and fat are pleasing in our mouths. So we need more than just knowledge that we are eating well and thereby preventing future disease while improving our health. Knowledge is important because most people just do not realize the extent of the harm that comes from over consumption of ultraprocessed foods. With knowledge we can follow the advice of Pollan in his “In Defense of Food” to never buy a product that has more than five ingredients or has ingredients that we have never heard of or cannot pronounce. But knowledge alone is just not incentive enough to overcome the temptations.

Some thoughts: Government can help with how it subsidizes agriculture, incenting the growth of a broader array of crops and not marking the fattest meat as “prime.” And it can continue to insist that restaurants, especially fast food outlets, display calorie counts. Business can help with wellness programs that reduce the employee share of health insurance premiums in return for weight reduction or exercise programs. Insurance can offer incentives as well. Schools can offer only quality foods – good in itself but also a lesson in good dietary habits for our children in their formative years. And we each need to create our own incentives – as I typed this I also ate a chocolate chip cookie. I enjoyed it but have set myself a limit of one per day. My treat for finishing this blog post.

Monday, April 11, 2011

Surprise – Adolescent Obesity Leads To Later Heart Disease and Diabetes

Well, probably not a surprise at all. The seeds of coronary artery disease (CAD) are laid down early and over long periods. But given our current pandemic of obesity beginning in childhood, should we worry about an epidemic of chronic disease like diabetes and CAD in the years to come? The clear answer is a resounding “Yes.”

There has been a long term study of military men in the Israeli Defense Force. An article in the New England Journal of Medicine, April 7, 2011 reports on what happened over an average follow-up of 17 years after army induction at age 17 for those who chose to remain in the military after the required three years. This amounted to 37,674 healthy men followed for about 650,000 person years. Among them, 1173 developed diabetes type 2 over time and 327 developed angiography-proven CAD. All by the age of 45.

Here is the baseline data:

Blood pressure, resting heart rate, fasting blood sugar, and low density lipoprotein (LDL – the “bad stuff”) and smoking incidence progressively increased with increasing BMI (BMI, a calculated ratio of weight and height) among the 17 year old inductees. High density lipoproteins (HDL – or the “good stuff”) declined as did the amount of weekly exercise with increasing BMI.

Here is the follow-up data:

Since this was a study of men beginning at age 17 and lasting an average of 17 years, it follows that the 327 cases of CAD and 1173 of diabetes were among relatively young men – aged 25-45 years old. When the investigators adjusted for age, family history of CAD, blood pressure, smoking status, LDL, HDL and triglycerides they found that an elevated BMI at age 17 was a significant independent risk factor for CAD. Indeed the risk increased by 12% for each increment of 1 unit of BMI. They also noted that CAD occurred even in those with BMIs that are generally considered within the acceptable range today.

BMI at age 17 also predicted for the later development of diabetes mellitus type 2 (DM) with risk increasing about 10% for each additional 1 unit of BMI. But with diabetes, it was the adult level (age 25 and beyond) that was associated with a greater increase in diabetes relative risk. Said differently, higher levels of BMI at age 17 correlate with higher risk of CAD and diabetes in early adulthood. Persistent elevations of BMI increase that risk. Elevation in early adulthood increases the risk of DM during early adulthood whether or not the person had a higher BMI at age 17.

My takeaway:

It is imperative to intervene now in the growing pandemic of childhood and adolescent obesity. Even modest increases BMI can predispose to later CAD and DM. Once developed, these are chronic illnesses that persist for life, are challenging to manage, are expensive to treat and have a high impact on both quality of life and longevity. Our children are our future; it is our obligation to protect them. And if that is not reason enough, then think of your wallet. The high costs of their care will have a very significant impact on each of us in our taxes and our insurance premiums.

Praise for Dr Schimpff

The craft of science writing requires skills that are arguably the most underestimated and misunderstood in the media world. Dumbing down all too often gets mistaken for clarity. Showmanship frequently masks a poor presentation of scientific issues. Factoids are paraded in lieu of ideas. Answers are marketed at the expense of searching questions. By contrast, Steve Schimpff provides a fine combination of enlightenment and reading satisfaction. As a medical scientist he brings his readers encyclopedic knowledge of his subject. As a teacher and as a medical ambassador to other disciplines he's learned how to explain medical breakthroughs without unnecessary jargon. As an advisor to policymakers he's acquired the knack of cutting directly to the practical effects, showing how advances in medical science affect the big lifestyle and economic questions that concern us all. But Schimpff's greatest strength as a writer is that he's a physician through and through, caring above all for the person. His engaging conversational style, insights and fascinating treasury of cutting-edge information leave both lay readers and medical professionals turning his pages. In his hands the impact of new medical technologies and discoveries becomes an engrossing story about what lies ahead for us in the 21st century: as healthy people, as patients of all ages, as children, as parents, as taxpayers, as both consumers and providers of health services. There can be few greater stories than the adventure of what awaits our minds, bodies, budgets, lifespans and societies as new technologies change our world. Schimpff tells it with passion, vision, sweep, intelligence and an urgency that none of us can ignore.

-- N.J. Slabbert, science writer, co-author of Innovation, The Key to Prosperity: Technology & America's Role in the 21st Century Global Economy (with Aris Melissaratos, director of technology enterprise at the John Hopkins University).