Heart failure in chronic kidney disease – Cardiology Basics

Heart failure in chronic kidney disease – Cardiology Basics

Prevalence of both heart failure and chronic kidney disease (CKD) are increasing as the population is aging globally. Hence heart failure in chronic kidney disease is seen more often. Presence of CKD in heart failure increases morbidity and mortality. Though there is increasing use of effective medications and special devices like cardiac resynchronization therapy in heart failure patients in general, those with CKD have not been benefited well.

CKD is defined as abnormalities of kidney structure or function, present for >3 months, with implications for health. A more detailed definition is persistently reduced estimated glomerular filtration rate (eGFR) of <60 ml/min per 1.73 sq. m. or at least 1 marker of kidney damage for >3 months. The markers of kidney damage include albuminuria, urine sediment abnormalities, histological, or structural abnormalities detected on imaging. History of renal transplantation is also included among markers of kidney damage. Significant albuminuria is albumin excretion rate of 30 mg/24 hours or more and albumin creatinine ratio of 30 mg/g or more.

Heart failure can occur in those on dialysis as well as those who have kidney disease not requiring dialysis. Naturally those on dialysis have more advanced kidney disease. Major medications used in heart failure can also be used in those with heart failure and mild-moderate CKD. But caution is needed because angiotensin converting enzyme inhibitors, angiotensin receptor blockers and mineralocorticoid receptor antagonists can cause hyperkalemia. Some may occasionally lead to transient worsening of kidney function as well. Beta blockers have been shown to improve outcomes in heart failure with reduced ejection fraction in all stages of CKD.

Angiotensin receptor neprilysin inhibitor (ARNI) therapy has been used successfully in randomized trials in patients with eGFR as low as 20 ml/min per 1.73 sq. m. Treatment with sodium-glucose cotransporter inhibitor (SGLT2) improved mortality and hospitalization in heart failure with reduced ejection fraction and CKD stages 3 and 4, having eGFR>20 ml/min per 1.73 sq. m. Caution has to be exercised while using high dose combination diuretic therapy, often unavoidable in heart failure with CKD. They have the risk of worsening renal function and electrolyte imbalances.

Those with CKD often have associated anemia as kidney is involved in synthesis of erythropoietin. Intravenous iron therapy is another important aspect of treatment in patients with heart failure and CKD. High dose iron has been shown to reduce heart failure hospitalization by 44% in patients on dialysis. Improved symptoms have been noted in heart failure in stage 3 CKD.

Heart failure device is otherwise known as cardiac resynchronization therapy or CRT, as it synchronizes the contractions of different parts of the left ventricle by giving appropriately timed stimuli. The procedure is done by implanting a device subcutaneously and connecting with three leads introduced through veins into right atrium, right ventricle and a tributary of the coronary sinus. Lead in the posterolateral tributary of coronary sinus is used to pace the left ventricle.

The expensive device can be implanted only in eligible patients with heart failure as determined by tests like ECG and echocardiogram. Left bundle branch block with wide QRS complex is usually taken as a surrogate for left ventricular dyssynchrony on the ECG. Echocardiogram will document severe left ventricular systolic dysfunction and mechanical dyssynchrony. CRT has been shown to reduce mortality and hospitalizations in patients with heart failure and stage 3 CKD.

Another method which can used to remove excess fluid from the body in patients with CKD is peritoneal dialysis. In peritoneal dialysis, a special fluid is put inside the peritoneal cavity using an implanted catheter. Peritoneum can exchange extra fluid into the special fluid. The fluid is drained after a few hours, removing waste products and excess water. The composition of the fluid instilled can be tailored to the need for removal of fluid and electrolytes.

This can be done at home by the caretaker if the peritoneal dialysis catheter has been inserted from the hospital. But care has to be taken to avoid removing too much fluid as it can lead to hypotension. Advice from the treating nephrologist has to be followed in this regard. Peritoneal dialysis can be used in patients with symptomatic fluid overload to improve symptoms and avoid hospitalizations.

Another special technique to remove excess fluid from the body in CKD patients with heart failure is by ultrafiltration during usual dialysis from the hospital or dialysis centre. This is done by giving negative pressure across the dialysis membrane by the dialysis machine. Same caution is needed in this case also to avoid removing too much fluid, as hypovolemia can lead to hypotension. A multidisciplinary approach combining cardiology and nephrology services is needed for optimal management of heart failure in patients with CKD. Of course, it is a usual practice in multi-system ailments.