Standard therapies for pulmonary arterial hypertension

Intravenous Diuresis in Severe Precapillary Pulmonary-Hypertension-Related Right Heart Failure: Effects on Renal Function and Blood Pressure

In patients with right heart failure (RHF) and pulmonary hypertension (PH), classical teaching often advises cautious diuresis in the setting of 'preload dependence' to avoid renal injury and hemodynamic compromise. However, while this physiology may hold true in some clinical settings, such as acute ischemia with right ventricular infarction, it cannot necessarily be extended to PH-related RHF. Rather, in patients with precapillary PH and decompensated RHF, diuresis aimed to decongest the right heart and systemic venous system may be directly beneficial. This study aimed to evaluate the effects of diuresis on renal function and blood pressure in patients with severe precapillary PH. A retrospective chart review was conducted on 62 patients with severe precapillary PH admitted for decompensated RHF. The hemodynamic phenotype of these patients was characterized by invasive hemodynamics and echocardiographic data. Laboratory and hemodynamic data were collected at both admission and discharge. After large-volume diuresis in this patient population, there was an improvement in both glomerular filtration rate and creatinine. While there was a decline in blood pressure after diuresis, this was not clinically significant, given the blood pressure remained in a normal range with improvement in renal function. In conclusion, this study demonstrated that despite concern for preload dependence, significant diuresis in patients with acute decompensated RHF from precapillary PH is not only safe but beneficial.

Contemporary Pharmacotherapeutic Approach in Pulmonary Arterial Hypertension

Since the 1973 World Symposium on Pulmonary Hypertension, advancements in the understanding of pathophysiology and pathobiology have led to a myriad of pharmacotherapies for the disease. This article journeys through the development of therapeutic approaches for pulmonary arterial hypertension.

Out of proportion pulmonary hypertension in obstructive lung diseases

PURPOSE OF REVIEW

Pulmonary hypertension is common (25-90%) in chronic obstructive pulmonary diseases (COPDs). Severe pulmonary hypertension, however, is quite rare (1-3%). The term 'out of proportion' pulmonary hypertension is still widely used. New guidelines instead propose to use the term 'Severe pulmonary hypertension' if mean pulmonary arterial pressure at least 35 mmHg or cardiac index (CI) is less than 2.0 l/min/m on right heart catheterization (RHC). Why only a minority of COPD patients develop severe pulmonary hypertension is unclear.

RECENT FINDINGS

When present, severe pulmonary hypertension in COPD is associated with increased dyspnea and decreased survival and often does not closely correlate with degree of obstructive abnormality on pulmonary function testing. COPD patients with severe pulmonary hypertension experience circulatory limitation at maximum exercise, and not ventilatory limitation, which is typical for moderate-to-severe COPD patients with no or moderate pulmonary hypertension.

SUMMARY

There is no conclusive evidence to support or completely reject the possibility of the use of specific pulmonary arterial hypertension (PAH) therapies in pulmonary hypertension associated with COPD. In mild-to-moderate COPD patients who have severe and progressive symptoms, and have evidence of severe pulmonary hypertension on RHC, specific PAH therapies may be used similar to WHO group-I PAH guidelines.

Standard nonspecific therapies in the management of pulmonary arterial hypertension

Recent advances in pulmonary arterial hypertension (PAH) research have created a new era of PAH-specific therapies. Although these therapeutics have revolutionized PAH therapy, their innovation was predated by supportive but nonspecific medical therapies adapted from their use in more common cardiopulmonary diseases. These therapies include oxygen therapy, diuretics, digoxin, anticoagulation, and high-dose calcium channel blockers. Expert opinion continues to support the use of adjunct therapies based on current pathologic understandings of PAH combined with some evidence extrapolated from small studies. This article discusses why these therapies continue to play an important role in the treatment of patients with PAH.

Pulmonary veno-occlusive disease: the bête noire of pulmonary hypertension in connective tissue diseases?

Pulmonary veno-occlusive disease (PVOD) is a rare form of pulmonary hypertension that may develop in patients with connective tissue diseases (CTD). Most cases have been reported in patients with systemic sclerosis, though associations with systemic lupus erythematosis and mixed connective tissue disease have also been described. PVOD is characterised by progressive obstruction of small pulmonary veins and venules that leads to increased pulmonary vascular resistance, right heart failure and premature death. Distinguishing PVOD from pulmonary arterial hypertension (PAH) is often difficult, though use of a diagnostic algorithm may improve diagnostic accuracy and preclude recourse to lung biopsy. The finding of normal left-heart filling pressures in the context of radiological studies suggestive of pulmonary oedema is an important diagnostic clue, particularly if this clinical scenario coincides with the introduction of vasodilator therapy. There are no approved treatments for the disorder, though cautious use of PAH specific therapy may improve short-term outcomes in selected idiopathic PVOD cases. This review summarises the epidemiologic, clinico-pathologic and imaging characteristics of PVOD in the setting of CTD and discusses potential management approaches.

Prevalence of acute vasoresponsiveness in patients with pulmonary hypertension: treatment implications

OBJECTIVE

Pulmonary hypertension (PH) is a serious and often progressive disorder that results in right ventricular dysfunction. The general reported rate of patients who are responders is 10%-26%. More recently, using the current criteria, the rate of acute vasodilator response was as low as 6%. This study used the most current guidelines to assess the prevalence of acute vasoresponsiveness in patients with PH.

METHODS

A retrospective chart review of 618 patients seen in the PH clinic at the Mayo Clinic Jacksonville from 1991 to June 2008 was conducted. We assessed the prevalence of acute vasoresponsiveness in patients with PH who had undergone vasodilator trial with epoprostenol or nitric oxide, using the current accepted criteria.

RESULTS

One hundred and seventy-six patients who underwent a vasodilator trial that had complete hemodynamic data were identified. The average age was 61 +/- 14 years and most were women (67%). The PH was severe with most patients in the World Health Organization (WHO) functional class III-IV (82%), and an average mean pulmonary artery pressure of 48 +/- 11 mm Hg. Although the study group included all WHO diagnostic groups, 69% were diagnosed as Group I pulmonary arterial hypertension. We found an overall prevalence of response to acute vasodilator therapy to be 26%.

CONCLUSION

Using the most current criteria to identify acute responders to vasodilator therapy in PH patients, we found a slightly higher rate of "responders" than previously reported. Acute vasodilator testing identifies a clinically important group who may benefit from calcium channel blockers (CCBs), and this study confirms that a significant percentage of PH patients are acutely vasoresponsive.

The successful use of phosphodiesterase type 5 inhibitors to treat the syndrome of cor pulmonale and prerenal azotemia with diuresis of anasarca (CorPRADA)

BACKGROUND

The occurrence of deteriorating renal function test results along with the attempts at diuresis of anasarca has been described but not named, and no solution other than the standard treatment of related medical conditions such as congestive heart failure (CHF) and reducing or stopping diuretics has been offered. Phosphodiesterase type 5 inhibitors (PD5I) are known to reduce pulmonary hypertension (PH). The PD5Is sildenafil and, just recently, tadalafil, have FDA indications in primary pulmonary hypertension (PPH).

METHODS

In this observational study of CorPRADA patients treated with PD5I, 12 out of 19 cases met criteria for inclusion in statistical analysis. Medication reductions/discontinuations generally were made. Pre- and post-treatment data were analyzed using matched pairs.

RESULTS

There were significant improvements in edema, glomerular filtration rate (GFR), weight, and loop diuretic dosage required, while strong trends were seen in urine output per day and urine output per unit loop diuretic per day.

CONCLUSION

The identification of CorPRADA and the use of standard treatments for PH plus PD5I medication show promise in achieving successful diuresis of anasarca while stabilizing or improving renal function simultaneously.

Pulmonary arterial hypertension in human immunodeficiency virus infection

Because of the improvement in survival rates of human immunodeficiency virus (HIV)-infected patients after the introduction of combined antiretroviral therapy, pulmonary arterial hypertension (PAH) has become an important cause of morbidity. As the awareness of PAH has increased, it is more likely that this condition will be diagnosed more frequently and earlier in the course of the disease and HIV infection. The etiopathogenesis is not clear; no evidence of direct infection of the pulmonary vascular tree has been found and the current evidence seems to favor a role of dysregulated cytokine response to HIV infection. The pathological changes of plexiform arteriopathy are indistinguishable from the pathological changes of idiopathic pulmonary arterial hypertension (IPAH). Dyspnea is the most common presenting symptom. Echocardiography, though always not accurate in diagnosing PAH and estimating its severity, remains the main screening tool. Right heart catheterization is the gold standard investigation for diagnosis. New therapies like prostanoids, endothelin receptor antagonists, and phosphodiesterase inhibitors have improved the outcome of patients with HIV-associated PAH. However, the overall prognosis of HIV-infected patients who develop PAH still remains poor.