A reasonable and prompt cardiovascular evaluation of the cardiovascular system including cardiac risk factors, may help control of this complication.

Hypertension in dialysis patients

 

There is no enough data concerned with the management of hypertension in dialysis patients, however, certain recommendations may be admitted in this concept. A reasonable and prompt cardiovascular evaluation of the cardiovascular system including cardiac risk factors in particular, may help control of this serious complication. Two important techniques may have crucial role in this concept, ambulatory blood pressure monitoring as well as cardiac echocardiography.

 

Volume overload 

Volume expansion is probably the fundamental factor that help in the evolution of high blood pressure (Hypertension) in patients on dialysis. Volume overload can induce hypertension in two mechanisms, first, elevation of cardiac output as well as elevation of the systemic vascular resistance. The latter effect may be induced due to activation of the RAS (renin-angiotensin system) or due to ouabain-like inhibitors secretion, that result in elevation in intra-cellular sodium and calcium. Rise in intra-cellular calcium can induce vascular smooth muscle vasoconstriction and elevation of blood pressure. However, whatever the mechanism, removing excess sodium and establishment of the "dry weight" (see below) may induce normalization of BP in > 60 % of hemodialysis patients and almost ALL patients on peritoneal dialysis.  The magnitude of extracellular volume expansion may be not severe enough to induce peripheral edema; so, lack of edema may not exclude the presence of hypervolemia.

 

 

Prolonged and/or more frequent hemodialysis

In Tassin, France, patients have commenced a protocol of prolonged and slow hemodialysis in the form of thrice weekly eight hourly dialysis. Surprisingly, almost all patients became normotensive with no medications at all. In addition to optimizing fluid overload, other factors may be also included like removal of uremic toxins and decline of sympathetic nervous activity. Moreover, patients with fluid overload still normotensive. Fortunately, this protocol of dialysis that is not widely applied, is associated with a better patient survival.

 

Nocturnal hemodialysis

This mode of dialysis can be performed 6-7 nights per week while the patient is sleeping (usually 6-12 hours) according to the duration of sleep and results in perfect BP control. Surprisingly, almost ALL patients commencing nocturnal dialysis became normotensive with no medications. They have achieved this goal via progressive decline of their target weight until they omit all their anti-hypertensive medications. Moreover, certain trials have reached normal blood pressure without medications and correction of the left ventricle enlargement via commencing short daily dialysis. A recent recommendation by the European Best Practice Guidelines that increasing the timing and/or frequency of dialysis should be augmented in hypertensive patients despite optimizing volume deloading. Target blood pressure (BP) should be individualized in every patient situation. The lowest tolerable BP should be consistent with the general feeling of sense of well-being without any hypotensive episodes between dialysis sessions. Whilst the ideal suggested BP before dialysis should be less than 140/90 mmHg, the ideal BP after dialysis should be less than 130/80 mmHg. However, with strict clinical supervision, the normal BP can be defined as a mean BP of less than 135/85 mmHg per day time and less than 120/80 mmHg per night.

 

To achieve this goal of control, the following maneuvers may be applied:

1]    Gradual withdrawal of the anti-hypertensive medications should be instituted unless there are medications with cardiac background until the “dry weight” could be recognized.

2]    This trial, however, should be attempted through 3-4 weeks in young patients, whilst this trial should be prolonged up to 12-14 weeks in old patients or those with vessel disease.

3]    If BP still high despite the establishment of the patient’ dry weight, the antihypertensive medications should be resumed.

4]    Preference of certain groups of antihypertensive medications depends to a great extent upon patient’s experience of these agents in regard to its side effects and their tolerance. A single daily dose, preferably at night is usually advised.

5]    A well-known international guideline (The K/DOQI) suggest the use of ACE inhibitors (ACEi) or angiotensin II receptor blockers (ARBs) due to the observed cardiac beneficial effects.

6]    Adequate dialysis should be the underlying base of therapy for all patients.

7]    Patient’s weight between dialysis sessions (interdialytic weight gain) should be properly adjusted according to K/DOQI guidelines (1-2 kilograms), a supervision of a dietitian is warranted in this concept to regulate: low sodium consumption, augment ultrafiltration (fluid withdrawal), and/or increased daily dialysis dose.

8]    To avoid the antihypertensive adverse effect of “erythropoietin”-hormone used to treat anemia-its dosage should be kept at its lower limits with a slow progress in anemia correction.

N.B. This Blogger is created to declare how can HT developed in HDX patients.