Treating Pulmonary Arterial Hypertension When There is Also Another Medical Problem, Such as Diastolic Heart Failure.
We have received a variety of questions about how to treat pulmonary arterial hypertension when a second medical problem is present at the same time. This is a very common situation in clinical practice. I would like to focus on how to approach the patient who has features of PAH and diastolic heart failure. Unfortunately, there is a paucity of good quality studies to help guide physicians. As a result, all we have to rely on is our experience and best judgment.
First, a quick primer on diastolic heart failure:
The left ventricle performs two main actions. It squeezes and then relaxes. During the squeeze phase (systole) blood is ejected through the aortic valve into the aorta where it flows throughout the body. Next, the left ventricle must relax quickly in order to receive blood from the top chamber on the left side (left atrium). Failure of the left ventricle to relax quickly enough results in the pressure rising prematurely inside the left ventricle during the relaxation phase (diastole). As the pressure rises inside the left ventricle during the relaxation phase, this causes pressure to rise inside the left atrium and then the pulmonary veins and eventually the pulmonary arteries.
We recognize left ventricular diastolic dysfunction or diastolic heart failure by certain findings on echocardiography and a characteristic pattern of pressure elevation found during right heart catheterization. The echo may not always show diastolic dysfunction even when it is present. The right heart catheterization findings that support diastolic heart failure are an elevated pulmonary capillary wedge pressure with preserved squeeze of the left ventricle.
Initially the pulmonary artery pressure rises due to passive congestion or high pressures from the left side of the heart. However, over time, chronically elevated left sided pressures can lead to structural changes in the pulmonary arteries that are indistinguishable from PAH. At this time, the right heart catheterization will show high pulmonary artery pressures and high pulmonary capillary wedge pressures and an elevated pulmonary vascular resistance.
Diastolic heart failure is now the most common type of left heart failure. This is due to the rising incidence of obesity and an aging population. Other risk factors include high blood pressure, diabetes, female gender, coronary artery disease and obstructive sleep apnea. Because of the high prevalence of diastolic heart failure, we now see many patients that have both diastolic heart failure and pulmonary hypertension. This is sometimes referred to as pulmonary hypertension out of proportion to the diastolic heart failure.
Management of Pulmonary Hypertension in the Setting of Diastolic Heart Failure
First, we take great care to ensure that the data upon which the diagnosis of pulmonary hypertension and diastolic heart failure is of good quality. Failure to obtain clean data at heart catheterization may mask the true diagnoses.
Next, we focus on risk factor modification. This means controlling systemic blood pressure, treating sleep apnea and most importantly weight loss. Obesity directly correlates with stiffness of the left ventricle. As patients lose weight, their left heart function improves and as they gain more weight the function deteriorates.
Next we focus on adjusting diuretics to remove all the excess salt and fluids that accumulate in diastolic heart failure. This is often a challenge as the kidney function often does not tolerate removal of fluid and the creatinine rises. Finding the right balance between the kidneys and the heart/lungs can be a challenge. We often have to tolerate mild to moderate elevations in the creatinine.
Often there are medications that promote fluid retention that need to be reduced or discontinued. Commonly encountered examples of medications that can promote fluid retention in diastolic heart failure patients include gabapentin (Neurontin), pregabalin (Lyrica), NSAIDS such as motrin, aleve, diclofenac, and narcotic pain medications. We also tend to reduce the dose of beta blockers if they are being used.
Finally, once we have removed as much of the extra fluid as possible, we consider using PDE-5 Inhibitors (Adcirca, or Revatio/sildenafil) in patients who have significantly elevated pulmonary vascular resistance. We avoid endothelin receptor antagonists (ERA) such as Tracleer, Letairis and Macitentan as they can lead to further problems with fluid retention. In general, there is also no role for prostanoid family medications (Remodulin, Tyvaso, Orenitram, Veletri and Epoprostenol). It is important to emphasize that there is not a clear body of evidence supporting this strategy only years of experience. Unfortunately, there is a paucity of medicines available to treat diastolic heart failure directly. Similarly, patients with diastolic heart failure have been carefully excluded from the studies of PAH medications.