Understanding Pulmonary Hypertension in Multiple Myeloma

Multiple myeloma comorbidities may contribute to the development of pulmonary hypertension.

Pulmonary hypertension is not a typical comorbidity to have when diagnosed with multiple myeloma (MM).

When the complication does occur, it is generally mild-to-moderate and may be secondary to a variety of conditions, which include left ventricular dysfunction, high-output cardiac failure, chronic kidney disease, treatment-related toxicities, and precapillary involvement.

A recent study evaluated the occurrence of pulmonary hypertension in 3 patients showing signs of the complication.

Each patient underwent right heart catheterization. All 3 patients exhibited elevated pulmonary pressures, transpulmonary gradients, and pulmonary vascular resistance. Patients were treated with pulmonary vasodilator therapy, and experienced improvement in their cardiopulmonary symptoms.

While pulmonary hypertension occurs in only a few patients diagnosed with MM, the complications presented can be quite complex. An elevation in pulmonary pressure may be seen for a variety of reasons, so it is important for physicians to consider all possibilities when treating these patients.

Physicians should also be aware of comorbidities typical of MM that may contribute to the development of pulmonary hypertension. These conditions include AL amyloidosis, renal disease, pulmonary vasculopathy, treatment-related vasculopathy, inflammation, POEMS syndrome, high-output heart failure and other cardiac diseases.

High-output heart failure and other cardiac disease may put patients at higher risk for developing pulmonary hypertension, according to the study.

Although few studies have focused on the incidence of pulmonary hypertension in the setting of high-output heart failure, there is a physiologic rationale that an inappropriately high cardiac output, especially in the setting of a noncompliant LV, will promote LA hypertension and subsequent pulmonary hypertension, the authors wrote.

While it is reasonable to conclude that patients with MM represent a mixed population who can have elevated pulmonary pressures for a variety of reasons, it should be noted that despite elements of left-sided heart disease, all 3 patients had normal to slightly elevated filling pressures at the time of right heart catheterization, all had elevated transpulmonary gradients and pulmonary vascular resistance, and all demonstrated improvement in cardiopulmonary symptoms after initiation of pulmonary vasodilator therapy.

Thus, there is a strong suspicion that a component of pulmonary arteriopathy was present in each patient studied. The mechanisms that lead to pulmonary arteriopathy may be inherent to the myeloma itself or may be a function of the various therapies employed in this patient population.

As a result, caregivers should be on the lookout for pulmonary hypertension in patients with MM. The etiology in most cases is likely to be multifactorial, although a complete understanding of the underlying pathobiology is currently lacking.

It is important to recognize instances of pulmonary hypertension in MM because pulmonary vasodilator therapy may be beneficial in certain cases.

Further studies, however, are required in order to better understand the prevalence, prognosis, and pathophysiology of pulmonary hypertension in this patient population and to help more effective treatments.