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Nocturnal Home Hemodialysis & Heart Disease: When is More Better?

When is more … better? 
More … dangerous heart rhythms? No way! More … episodes of not being able to breathe the night before dialysis? Not likely! More … muscle cramps, weakness, nausea and vomiting near the end of dialysis? Ummm – no! The correct answer: more dialysis treatments per week and more time per dialysis session.

Lengthening the amount of time a person dialyzes may not make sense if you are one of the many people who experience dialysis side effects such as muscle cramps, headache, weakness and/or dizziness during the last hour of treatment. Instead, your common sense might suggest if you get sick during the last hour of dialysis, simply shorten the treatment to eliminate that final hour and you won’t get sick anymore. Keep in mind, these side effects are largely due to rapid fluid removal and rapid clearance of metabolic waste products during the dialysis treatment. To maintain an “adequate dialysis” (e.g., KT/V > 1.2), a shortened treatment must be more intense (i.e., faster blood flow rate, bigger artificial kidney and faster bath flow rate). In other words, if T=time and time decreases, then K=clearance, must increase to maintain an “adequate dialysis” session (KT/V) and ensure the person is getting an effective treatment. Because a shorter treatment would have to be more “intensive” to be as effective, the muscle cramps, headache, weakness and/or dizziness would still occur near the end of the dialysis treatment – regardless of how short the dialysis treatment lasts. If this scenario is accompanied by excessive fluid gains, the same symptoms may be even more severe. Perhaps a better explanation to visualize the process of dialysis is as follows:

Let’s say you have a 65-year-old (close to the author’s age) washing machine. The washing machine requires a certain amount of time to effectively clean and rinse a big load of laundry. This “mature” washing machine still works perfectly well as long it is treated gently. Now let’s say, the washing machine starts over-heating near the end of the wash cycle. It always seems to happen near the end of the cycle. So what do you do? If you merely shorten the washing time to avoid the end-of-wash over-heating, the machine doesn’t have enough time to get the soap out of your clothing. So, in addition to shortening the time for the wash, you must also make the “mature” washing machine wash, rinse and spin faster to get the soap out of your clothes before the time you think it will begin over-heating. What happens when you try this? The stressed motor over-heats sooner and “hotter” during every wash. So the problem is actually made worse instead of better. What would be a reasonable fix for this machine? Slow it down so it doesn’t have to work so hard and prolong the wash time at the slower speed to still get the laundry clean and the soap out.

Your body’s “wash” during dialysis behaves similarly. The way to make dialysis more “gentle” (i.e., avoiding cramping, nausea, vomiting, headache, blood pressure drops, fatigue and dizziness) while still getting the job done properly (adequate dialysis) is to slow the treatment, prolong the treatment and have treatments more frequently per week.

Growing numbers of people are receiving four to six dialysis treatments per week – some in dialysis centers, others overnight in dialysis centers and many at home. When the treatments are during the day, dialysis can erode time available to “live life” off dialysis. But if long, slow, frequent dialysis is performed at home and overnight while sleeping, then every hour of every waking day is free from dialysis! Let’s now examine the impact of nocturnal home hemodialysis (NHHD) on the most important outcome – survival.

The most common causes for death in people with end stage renal disease (ESRD) are not directly related to ESRD. Instead, the most common causes of death are cardiovascular events. The two most common cardiovascular causes are sudden death due to life threatening heart rhythms and severe chronic congestive heart failure (often called cardiomyopathy). How and why do these complications occur and can dialysis improve them, thereby improving survival?

Evidence is emerging that sudden death in a person with ESRD is most commonly caused by fatal heart rhythms originating in thickened (called left ventricular hypertrophy or LVH) and scarred (called myocardial fibrosis) tissue in the wall of the major pumping chamber of the heart, the left ventricle. The scar tissue in the heart is thought to be the origination site for those abnormal, fatal electrical rhythms. Also, a thickened, scarred left ventricle is associated with eventual weakening of the heart muscle, called chronic congestive heart failure, or cardiomyopathy. Therefore LVH is related to the most common causes of death in people with ESRD. LVH and myocardial fibrosis occur to the left ventricle when the heart is exposed to chronic volume (volume = water and salt) overload in the body, especially in the blood stream. Volume overload worsens in people as chronic kidney disease progresses.

Studies are beginning to show that conventional, standard dialysis improves this heart abnormality in approximately 50 percent of people, but around 30 percent of people actually have worsening thickening and scarring of their hearts. Those people who had worsening left ventricular thickening and scarring also have a much poorer survival rate. With NHHD, on the other hand, almost 90 percent of people show significant improvement in LVH. At least one study following people treated by NHHD for 10 years found significant improvement in LVH, decreased cardiovascular events and improved survival.

There are added benefits in addition to reduction of harmful cardiovascular events and improved survival. NHHD also improves phosphate control, often without any dietary restrictions or medication – same for potassium and fluid. Anemia improves without as much or any erythropoietin medication (ESA). Blood pressure often improves to normal without medications, or at least reduced dosages and number of medicines prescribed. With NHHD, there are virtually no diet restrictions; a person’s appetite tends to improve along with their strength and overall nutrition. When strength and appetite improve with fewer restrictions, quality of life usually improves.

For additional information on home dialysis therapies, contact AAKP for a complimentary copy of Understanding Your Hemodialysis Options and Understanding Your Peritoneal Dialysis Options. These brochures may also be downloaded for free by visiting, www.aakp.org/brochures.

NHHD ……………………………………… nightly home hemodialysis
ESRD ……………………………………….. end stage renal disease (kidney function is less than or equal to 10% of normal)
LVH …………………………………………. Left ventricular hypertrophy (thickening and scarring of the strongest pumping chamber in the heart)
LVMI ………………………………………. Left ventricular mass index (sensitive measure of thickening and scarring of the strongest pumping chamber in the heart) (usually measured by cardiac MRI scan without gadolinium)

Richard Goldman, MD, is a board member for the American Association of Kidney Patients (AAKP) and also serves on its Public Policy Committee. He is immediate past president of the Forum of End Stage Renal Disease Networks and continues to serve on the Forum board of directors. In addition to participation in many professional organizations, Dr. Goldman is the Chairman of the Board of Directors for ESRD Networks #15 and #17 and also serves as Chair of the Renal Physicians Association’s (RPA) Quality, Safety and Accountability Committee. He continues his active interests in performance measurement, advanced care planning, palliative care and transitioning from pediatric nephrology care to internal medicine nephrology care by childhood survivors of ESRD. He is semi-retired from clinical practice in Albuquerque, NM after a 30-year career as an internal medicine and pediatric nephrologist. 

This article originally appeared in the March 2011 issue of At Home with AAKP.