Pulmonary vasodilator testing and use of calcium channel blockers in pulmonary arterial hypertension

Abstract

Pulmonary arterial hypertension (PAH) encompasses a number of diseases responsible for a specific set of hemodynamic findings during right heart catheterization. During initial workup, pulmonary vasodilator testing is performed. A positive acute pulmonary vasodilator test predicts better survival and response to calcium channel blocker (CCB) therapy. There is lack of consensus on the preferred agent for determining acute pulmonary vasoreactivity. The ACCP guidelines and the 4(th) World Symposium on Pulmonary Hypertension support the use of intravenous epoprostenol or nitric oxide (NO) as the preferred agents for pulmonary vasodilator testing. A decrease in the mean pulmonary artery pressure by at least 10 mmHg to reach an absolute value of 40 mmHg or less without a decrease in cardiac output is currently considered a positive pulmonary vasodilator test. A positive test by the current recommended criteria is observed in about 10-15% of patients with idiopathic PAH. Approximately half of these patients will experience long-term benefits with CCBs. A positive test may select patients with an earlier or less aggressive form of disease, which may carry a better prognosis. A positive vasodilator test is observed very infrequently in patients with pulmonary arterial hypertension other than idiopathic PAH or anorexigen associated PAH. This article reviews the literature regarding pulmonary vasodilator testing and use of CCB therapy in patients with PAH, while identifying the gaps in knowledge concerning this diagnostic procedure.

Pulmonary Vascular Capacitance is Associated with Vasoreactivity and Long-Term Response to Calcium Channel Blockers in Idiopathic Pulmonary Arterial Hypertension

“…A positive test by the current criteria is observed in about 10-15 % of patients with IPAH. Approximately, half of these patients will experience long-term benefits with CCBs [18]. It is unclear why some patients may have an initial positive vasodilator test but fail CCB.…”

Acute Vasoreactivity Testing With Nicardipine in Patients With Pulmonary Arterial Hypertension

“…Acute vasoreactivity testing is most commonly performed using inhaled iNO (10), intravenous epoprostenol (11), or intravenous adenosine (12). However, several investigators have also pointed out a problem with these agents: it is important to consider that these agents have different mechanisms of action and diverse hemodynamic effects, and their use may therefore not be interchangeable (13,23). Since iNO vasodilates the pulmonary artery selectively and its halflife is very short (3 min), it has minimal systemic side ) 483 297 *SRAO2 was substituted for SPAO2, and cardiac output was calculated by the Fick oxygen method.…”

Pulmonary Hypertension Is a Probable NO/ONOO−Cycle Disease: A Review

“…ere are a variety of additional studies showing that elevated intracellular calcium levels have causal roles in PAH [273][274][275][276][277][278][279][280][281][282], including studies using calcium channel blockers [279][280][281][282] to obtain clinical improvement. It follows that agents lowering intracellular calcium may also be useful in therapy.…”