Heart Health Update

By David P. Faxon, M.D.

This year, 1.1 million Americans will suffer their first or a recurrent heart attack and about 440,000 of them will die as a result, according to the American Heart Association. Can research help reduce this lethal toll? It can, and it has. But heart disease, which often begins in childhood, remains the nation's leading single cause of death. In recent months, new insights into the causes, treatment and prevention of heart attacks have emerged to help in the battle.

Treatment
Bypass surgery saves lives, tens of thousands each year. Yet it is a major operation that requires cutting the chest open, removing a vein from elsewhere in the body and sewing it into an artery to reroute blood around a life-threatening blockage. Researchers are, however, experimenting with a far less invasive bypass procedure. Here's how it works:

1. A hollow, flexible tube called a catheter is inserted into one leg and threaded up to a clogged artery.
2. Then a physician, guided by ultrasound, pushes a needle from inside the catheter through the artery wall and into an adjacent vein.
3. Next, a tiny balloon is inflated to widen the hole and a tube is inserted between the two vessels.
4. Finally, the vein is blocked off just above the new channel, turning the vein into a substitute artery. Blood from the blocked artery flows down the vein to nourish the previously oxygen-starved heart muscle.

Diagnosis
Cardiologists often have trouble deciding whether someone with a moderately clogged artery should be treated with drugs or undergo balloon angioplasty, a nonsurgical procedure that can open an artery narrowed by heart disease. The challenge is that angiography, a diagnostic technique used to examine the arteries visually, only provides a two-dimensional image, which makes it difficult to determine the seriousness of a "borderline" blockage (an artery that is not totally blocked). Researchers recently found a better guide than artery narrowing for selecting angioplasty patients. They measured the pressure of blood flowing through a diseased artery and compared it to normal-flow arterial pressure. Previous studies had shown that patients with low blood flow should have angioplasty. The researchers randomized patients with borderline arterial blood flow into two groups. One group had angioplasty; the other did not. After two years the group that did not get the procedure had fewer deaths, nonfatal heart attacks or subsequent procedures to restore blood flow than the angioplasty patients did. The finding indicates that measuring the pressure of blood flowing through a diseased artery can help decide who can be treated with drugs and who should have angioplasty.

Prevention
It may be time to recheck your blood cholesterol, even if your doctor has told you in the past that it was fine. Increasing evidence shows that the lower your cholesterol, the better for your heart. And new guidelines recommend some lower cholesterol levels. A total cholesterol count of less than 200 remains the desirable level; 200-239 is borderline high; and 240 or more is high. For "bad" (LDL) cholesterol, however, the guidelines now list a count of less than 100 as best; 100-129 as near or above optimal; 130-159 as borderline high; 160-189 as high; and 190 or above as very high. A count of 40 or less for "good" (HDL) is low, and a count 60 or above is high (and therefore good).

Try Lifestyle Changes. High cholesterol doesn't necessarily mean you need drugs to lower it. The guidelines urge trying lifestyle changes first, such as a low-fat diet and exercise. Your physician is your best source to help you make decisions about lowering cholesterol.

Nutrition
Yes, a healthy diet helps your heart. Evidence from a three-part study suggests that lutein, a yellowish pigment in dark leafy vegetables and some other foods, can prevent atherosclerosis. This buildup of fatty deposits in artery walls can lead to heart attacks and strokes. Researchers measured lutein blood levels and the thickness of the carotid arteries in the necks of volunteers. They remeasured both 18 months later. The lowest increase in artery thickness was found in the 20 percent of the study group who had the most lutein in their blood. Arterial thickness increased fivefold in the 20 percent of the group who had the least. The fatty deposits in mice fed a lutein supplement averaged 44 percent smaller than those in animals that were not fed lutein.

Why Lutein? In laboratory studies, scientists examined human carotid arteries whose inner layer had been treated with lutein prior to removal during surgery. The lutein-treated layers attracted fewer white cells, wich oxidize LDL cholesterol. Oxidized LDL in artery walls is a major cause of atherosclerosis. Beware of Trans Fats. They may be more hazardous to your heart than the saturated fats that physicians have warned about for years. A new study compared people who ate a specially prepared trans-fat diet with a group who consumed a similar saturated-fat diet. Compared to those on the saturated-fat diet, trans-fat eaters averaged 21 percent lower "good" (HDL) cholesterol, and the ability of their blood vessels to dilate was reduced 29 percent. Both conditions put the heart at risk.

What are they? Trans fats are created when hydrogen atoms are forced into liquid oils, such as corn and soybean oil, to make them solid at room temperature. Nutrition labels call them "hydrogenated" or "partially hydrogenated" oils. They are common in margarine, packaged baked goods and fried foods in restaurants. Saturated fats are found in meat, other animal products and tropical oils such as coconut and palm.

Risk Factors
America may need to rethink the high number in a high blood pressure reading. A blood pressure reading yields two numbers: the systolic (high, or top, number) and the diastolic (low, or bottom, number)—128/82, for example. Systolic indicates the pressure when the heart is pumping; diastolic pressure reflects the heart at rest. Historically, physicians have emphasized the dangers of diastolic pressure and largely ignored systolic pressure. Too many still do. A high systolic pressure also threatens the heart.

Hidden Crisis? Half the people in the United States with hypertension have a normal diastolic pressure but a high systolic pressure. Their risk for heart attack, heart failure, stroke or kidney failure is even greater than it is for people with high numbers for both pressures. Yet many people with high systolic pressure alone go untreated because we haven't taken systolic pressure seriously enough.

A simple urine test may reveal early heart disease. Researchers measured levels of albumin in the urine of postmenopausal women and followed their health status for up to 18 years. Albumin is a common protein in the blood, but in the urine it signals kidney damage that can be caused by early, symptomless coronary artery disease. The amount of albumin detected was tiny. Nonetheless, the 20 percent of the women with the highest albumin levels had a cardiovascular death rate 4.4 times that of women in which no albumin was detected.

Help for Nondiabetics? Albumin in the urine occurs among diabetics and can be reduced by blood pressure drugs called ACE inhibitors. The question is whether reducing urine albumin in nondiabetics can reduce their risk of heart disease. Newer studies indicate that these findings apply to men and premenopausal women, as well as postmenopausal women.

Genetics
Familial combined hyperlipidemia (FCHL) is the most common genetic form of high cholesterol. This deadly combination of elevated cholesterol and high triglycerides (another form of blood fats) causes about 10 percent of all premature heart disease in the United States. People with FCHL have a greater heart risk than those with high cholesterol alone.

Mystery Gene? Now researchers have deciphered part of the FCHL puzzle, and it appears the disorder involves two separate processes. One is insulin resistance, the failure of cells to use insulin efficiently and long suspected as a factor in the FCHL. The second cause, previously unsuspected, is the overproduction of apolipoprotein B (apoB), a component of cholesterol. Now the search is on for the gene that increases apoB production.

Dr. Faxon is chief of cardiology at the University of Chicago School of Medicine and president of the American Heart Association.

For more information about heart disease and stroke, contact the American Heart Association at 1-800-AHA-USA-1 (1-800-242-8721) or visit our Web site at www.Americanheart.org.

The American Heart Association's best-selling cookbooks, with more than 4 million copies in print, are available from booksellers everywhere or by calling 1-800-793-2665.