Current therapies for pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disease of the pulmonary vasculature, characterized by relentless deterioration and death. Patients with PAH are known to be at increased risk for anesthetic complications and surgical morbidity and mortality. However, outcomes in patients have improved with the recent development of new drug therapies. The 3 major drug classes for treatment of PAH are prostanoids, endothelin-receptor antagonists, and phosphodiesterase-5 inhibitors. In this review, the authors provide an overview of each drug class, its mechanism of action, indications, and current supportive literature. Surgical and interventional treatments of PAH, including atrial septostomy, pulmonary thromboendarterectomy, and transplantation, are briefly reviewed, and the rationale, indications, and selection criteria for each are discussed. Although available medical and surgical therapies for PAH have improved patient outcomes, acute decompensated right heart failure (RHF) remains a common and challenging complication of PAH. The authors review this topic and provide an outline of the general pathophysiology of RHF and an approach to its management.

Outpatient cardiac infusion units: impact in elderly patients with refractory heart failure

BACKGROUND

The use of intermittent intravenous infusions of inotropic drugs is under evaluation in the management of patients with refractory heart failure.

OBJECTIVES

We investigated the impact of intermittent outpatient infusions of inotropes on hospital admissions, emergency room visits, functional class, and symptom-free interval after administration of inotropes to elderly patients with advanced heart failure symptoms.

METHODS

This retrospective analysis involved 24 elderly outpatients with a New York Heart Association class of III or IV and refractory heart failure symptoms.

RESULTS

Seven patients with class III heart failure (age 74A+/-4 years; left ventricular ejection fraction 27A+/-9%) and 17 patients of class IV (age 73A+/-4 years; LVEF 21A+/-10%) were included. Twenty patients were males. A total of 365 outpatient treatment sessions were administered, with 15A+/-9 sessions per patient (range, 6-43). Eleven patients improved and were discharged; seven patients died; three discontinued treatment; two patients remain on therapy; and one patient required continuous infusion. During this treatment, there were only three emergency room visits and six hospital admissions due solely to heart failure. Fourteen patients required no emergency room visits or hospitalization. Of the patients discharged from the program, the interval without heart failure symptoms ranged from 60-356 days, with an improvement in NYHA class from 3.5A+/-0.6 to 1.4A+/-0.5 and no emergency room visits or hospital admissions.

CONCLUSIONS

This type of therapy is well tolerated among elderly patients with refractory heart failure symptoms and its use deserves further investigation.

Evaluation of acute dual-chamber pacing with a range of atrioventricular delays on cardiac performance in refractory heart failure

OBJECTIVES

This study evaluated how variations in atrioventricular (AV) delay affect hemodynamic function in patients with refractory heart failure being supported with intravenous inotropic and intravenous or oral inodilating agents.

BACKGROUND

Although preliminary data have suggested that dual-chamber pacing with short AV delays may improve cardiac function in patients with heart failure, detailed Doppler and invasive hemodynamic assessment of patients with refractory New York Heart Association class IV heart failure has not been performed.

METHODS

Nine patients with functional class IV clinical heart failure had Doppler assessment of transvalvular flow and right heart catheterization performed during pacing at AV delays of 200, 150, 100 and 50 to 75 ms.

RESULTS

Systemic arterial, pulmonary artery, right atrial and pulmonary capillary wedge pressures, cardiac index, systemic and pulmonary vascular resistances, stroke volume index, left ventricular stroke work index (SWI) and arteriovenous oxygen content difference demonstrated no significant changes during dual-chamber pacing with AV delays of 200 to 50 to 75 ms. There were also no changes in the Doppler echocardiographic indexes of systolic or diastolic ventricular function. The study was designed with SWI as the outcome variable. Assuming a clinically significant change in the SWI of 5 g/min per m2, a type I error of 0.05 and the observed standard deviation from our study, the observed power of our study is 85% (type II error of 15%).

CONCLUSIONS

Changes in AV delay between 200 and 50 ms during dual-chamber pacing do not significantly affect acute central hemodynamic data, including cardiac output and systolic or diastolic ventricular function in patients with severe refractory heart failure due to dilated cardiomyopathy.