Acute vasodilator test in pulmonary arterial hypertension: Evaluation of two response criteria

Acute vasodilator response testing in the adult Fontan circulation using non-invasive 4D Flow MRI: a proof-of-principle study

BACKGROUND

Pulmonary vasodilator therapy in Fontan patients can improve exercise tolerance. We aimed to assess the potential for non-invasive testing of acute vasodilator response using four-dimensional (D) flow MRI during oxygen inhalation.

MATERIALS AND METHODS

Six patients with well-functioning Fontan circulations were prospectively recruited and underwent cardiac MRI. Ventricular anatomical imaging and 4D Flow MRI were acquired at baseline and during inhalation of oxygen. Data were compared with six age-matched healthy volunteers with 4D Flow MRI scans acquired at baseline.

RESULTS

All six patients tolerated the MRI scan well. The dominant ventricle had a left ventricular morphology in all cases. On 4D Flow MRI assessment, two patients (Patients 2 and 6) showed improved cardiac filling with improved preload during oxygen administration, increased mitral inflow, increased maximum E-wave kinetic energy, and decreased systolic peak kinetic energy. Patient 1 showed improved preload only. Patient 5 showed no change, and patient 3 had equivocal results. Patient 4, however, showed a decrease in preload and cardiac filling/function with oxygen.

DISCUSSION

Using oxygen as a pulmonary vasodilator to assess increased pulmonary venous return as a marker for positive acute vasodilator response would provide pre-treatment assessment in a more physiological state - the awake patient. This proof-of-concept study showed that it is well tolerated and has shown changes in some stable patients with a Fontan circulation.

Loss of response to calcium channel blockers after long-term follow-up treatment in patients with idiopathic pulmonary arterial hypertension

Idiopathic pulmonary arterial hypertension (PAH) patients with a positive response to acute vasodilator challenge and a clinical response to calcium channel blockers (CCBs) for at least one year are traditionally designated true responders. Nevertheless, little is known about a sustained response to CCBs over longer periods of time. We evaluated the loss of response to CCBs after long-term treatment in a cohort of idiopathic PAH patients previously classified as being true responders. Our data suggest that idiopathic PAH patients can lose clinical response to CCBs even after one year of clinical stability, reinforcing the need for constant multidimensional reevaluation to assess the need for targeted PAH therapies and to classify these patients correctly.

Prognostic value of longitudinal vasoreactivity in pediatric pulmonary hypertension

Upon diagnosis of pulmonary hypertension in pediatrics, standard practice often involves acute vasoreactivity testing (AVT) in the cardiac catheterization laboratory. However, the importance of repeated AVT testing in a given patient thereafter remains unclear. This study sought to describe serial AVT results in pediatric patients and understand the prognostic significance of longitudinal AVT results in pediatric pulmonary hypertension. A retrospective chart review was performed for pediatric pulmonary hypertension patients diagnosed between 2008 and 2021. Patients were included if they had two or more catheterizations with AVT. The study cohorts were patients who were AVT negative upon initial catheterization then AVT positive at any subsequent catheterization (AVT-/+) compared to those were AVT negative upon initial and all subsequent catheterizations (AVT-/-). A positive AVT was defined by Sitbon criteria. The analyzed outcome was event-free survival. The relationship between study cohorts and event-free survival was analyzed by log-rank Kaplan-Meier survival as well as Cox proportional hazard regression to control for confounders. There were 35 patients who met inclusion criteria in this time period. Patients who were AVT(-/+) had statistically significantly better event-free survival than AVT(-/-) (p = 0.002). In univariate and multivariate Cox regressions, a subsequent AVT positive result amongst those who were initially AVT negative was a positive prognostic factor, hazard ratio 0.03 (95% confidence interval: 0.02-0.35). For patients with negative AVT upon initial cardiac catheterization, this data supports that continuing AVT should be performed as any subsequent AVT positive result may indicate improved expectations for event-free survival.

Long-term prognostic value of cardiac catheterization and acute vasodilator testing with inhaled iloprost in pediatric idiopathic pulmonary arterial hypertension

To assess the long-term prognostic value of cardiac catheterization and acute vasodilator testing (AVT) with inhaled iloprost in children with idiopathic pulmonary arterial hypertension (IPAH). Data on 81 consecutive children with IPAH referred to our center who underwent cardiac catheterization and AVT between June 2008 and August 2019 were collected. The correlation between the invasive hemodynamic data and transplant-free survival was analyzed. Twenty-four patients died and 1 underwent lung transplantation during a median follow-up of 3.8 years, with a 5-year transplant-free survival rate of 64.9%. Univariate analysis showed that predictors associated with improved survival included a lower pulmonary vascular resistance index (PVRI), PVRI/systemic vascular resistance index (SVRI), mean pulmonary arterial pressure (mPAP)/mean systemic arterial pressure, mean right atrial pressure, and a higher cardiac index (CI), mixed systemic venous oxygen saturations (SvO2), and acute vasodilator response (AVR) according to the Barst criteria (decrease in mPAP and PVRI/SVRI ratio of >20% without a decrease in CI). In multivariate Cox regression analysis, Barst AVR and SvO2 were independently related to transplant-free survival. Multiple hemodynamic variables from cardiac catheterization and AVT with inhaled iloprost have important prognostic value for long-term survival in children with IPAH, of which pulmonary vasoreactivity defined by the Barst criteria and SvO2 are independent prognostic factors.

Electrical impedance tomography in pulmonary arterial hypertension

The characterization of pulmonary arterial hypertension (PAH) relies mainly on right heart catheterization (RHC). Electrical impedance tomography (EIT) provides a non-invasive estimation of lung perfusion that could complement the hemodynamic information from RHC. To assess the association between impedance variation of lung perfusion (ΔZ_Q) and hemodynamic profile, severity, and prognosis, suspected of PAH or worsening PAH patients were submitted simultaneously to RHC and EIT. Measurements of ΔZ_Q were obtained. Based on the results of the RHC, 35 patients composed the PAH group, and eight patients, the normopressoric (NP) group. PAH patients showed a significantly reduced ΔZ_Q compared to the NP group. There was a significant correlation between ΔZ_Q and hemodynamic parameters, particularly with stroke volume (SV) (r = 0.76; P < 0.001). At 60 months, 15 patients died (43%) and 1 received lung transplantation; at baseline they had worse hemodynamics, and reduced ΔZ_Q when compared to survivors. Patients with low ΔZ_Q (≤154.6%.Kg) presented significantly worse survival (P = 0.033). ΔZ_Q is associated with hemodynamic status of PAH patients, with disease severity and survival, demonstrating EIT as a promising tool for monitoring patients with pulmonary vascular disease.

Schistosomiasis-associated pulmonary arterial hypertension: a systematic review

Schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) is a life-threatening complication of chronic hepatosplenic schistosomiasis. It is suggested to be the leading cause of pulmonary arterial hypertension (PAH) worldwide. However, pathophysiological data on Sch-PAH are scarce. We examined the hypothesis that there are pronounced similarities in pathophysiology, haemodynamics, and survival of Sch-PAH and idiopathic PAH (iPAH).

This systematic review and meta-analysis was registered in the PROSPERO database (identifier CRD42018104066). A systematic search and review of the literature was performed according to PRISMA guidelines for studies published between 01 January 1990 and 29 June 2018.

For Sch-PAH, 18 studies evaluating pathophysiological mechanisms, eight studies on haemodynamics (n=277), and three studies on survival (n=191) were identified. 16 clinical registries reporting data on haemodynamics and survival including a total of 5792 patients with iPAH were included for comparison. Proinflammatory molecular pathways are involved in both Sch-PAH and iPAH. The transforming growth factor (TGF)-β signalling pathway is upregulated in Sch-PAH and iPAH. While there was no difference in mean pulmonary artery pressure (54±17 mmHg versus 55±15 mmHg, p=0.29), cardiac output (4.4±1.3 L·min−1versus 4.1±1.4 L·min−1, p=0.046), and cardiac index (2.6±0.7 L·min−1·m−2versus 2.3±0.8 L·min−1·m−2, p<0.001) were significantly higher in Sch-PAH compared to iPAH, resulting in a lower pulmonary vascular resistance in Sch-PAH (10±6 Woods units versus 13±7 Woods units, p<0.001). 1- and 3-year survival were significantly better in the Sch-PAH group (p<0.001).

Sch-PAH and iPAH share common pathophysiological mechanisms related to inflammation and the TGF-β signalling pathway. Patients with Sch-PAH show a significantly better haemodynamic profile and survival than patients with iPAH.

Pulmonary arterial hypertension in Latin America: epidemiological data from local studies

BACKGROUND

Pulmonary arterial hypertension is a rare, progressive disease with poor prognosis. However, there is limited information available on the characteristics of PAH patients outside of North America and Europe. This is particularly important as researchers have described that there are potential geographical and regional differences which are vital to consider in the design of clinical trials as well as PAH treatment. The aim of this study was to describe the epidemiology of PAH (PH group 1) in Latin America.

METHODS

A search of electronic databases for studies published in English, Spanish or Portuguese was conducted specifying publication dates from the 1st of January 1987 until 10th October 2016. Two authors independently assessed papers for inclusion and extracted data. A narrative synthesis of the findings was conducted.

RESULTS

The search revealed 22 conference abstracts and articles, and on application of the inclusion criteria, six conference abstracts and articles were included in the final review. Studies/registries were based in Argentina, Brazil and Chile. In contrast to the available literature from developed countries, in Latin America, most patients were diagnosed at younger age; nevertheless, the higher prevalence of idiopathic PAH (IPAH) and the advanced stage of the disease at diagnosis were comparable to the existing literature, as the long term survival, despite the lower availability of targeted therapies.

CONCLUSION

This study highlights the regional characteristics in the epidemiology of group 1 PH. The recognition of these differences should be considered when developing clinical guidelines and extrapolating diagnostic and treatment algorithms. Equitable access to health care and therapies are also issues that need to be addressed in Latin America. Information coming from a large prospective registry representing the different populations in Latin America is of critical importance to increase disease awareness in the region and improve diagnosis and management.

Use of direct oral anticoagulants for chronic thromboembolic pulmonary hypertension

OBJECTIVES

Chronic thromboembolic pulmonary hypertension is one of the most prevalent forms of pulmonary hypertension and is a major complication of acute pulmonary embolism. One mainstay of chronic thromboembolic pulmonary hypertension treatment is lifelong anticoagulation. The recent advent of direct oral anticoagulants for acute pulmonary embolism treatment has provided a viable and effective alternative for treating this condition. However, little is known about the efficacy of this new class of drugs for treating chronic thromboembolic pulmonary hypertension. We aimed to evaluate the safety and efficacy of direct oral anticoagulants in the treatment of chronic thromboembolic pulmonary hypertension.

METHODS

A cohort of chronic thromboembolic pulmonary hypertension patients who initiated treatment with direct oral anticoagulants between June 2015 and November 2016 were enrolled in this study.

RESULTS

Sixteen patients used rivaroxaban, three used dabigatran and one used apixaban for a mean follow-up of 20.9 months. The mean age was 51 years, and eighteen patients were classified as functional class II/III. Eight patients underwent a pulmonary endarterectomy and exhibited clinical, hemodynamic and functional improvement and currently continue to use direct oral anticoagulants. No episode of venous thromboembolism recurrence was identified during the follow-up period, but there was one episode of major bleeding after a traumatic fall.

CONCLUSIONS

Although direct oral anticoagulants appear to be a safe and effective alternative for treating chronic thromboembolic pulmonary hypertension, larger studies are needed to support their routine use.

Pulmonary hypertension in lymphangioleiomyomatosis: prevalence, severity and the role of carbon monoxide diffusion capacity as a screening method

Background

Lymphangioleiomyomatosis (LAM) is included within group 5 of the current PH classification (unclear multifactorial mechanisms). However, data regarding the occurrence of PH in LAM are scarce. The aims of the study were to describe the prevalence and characteristics of PH in a large cohort of LAM patients with different levels of severity, and to evaluate the role of echocardiography and carbon monoxide diffusion capacity (DL_CO) as screening methods for PH in LAM.

Methods

One hundred five LAM patients underwent transthoracic echocardiography, pulmonary function tests (PFTs) and 6-min walk test (6MWT). Patients with a suspicion of PH on echocardiography, defined by the presence of estimated systolic pulmonary artery pressure (PAP) over 35 mmHg or PFT showing DLco below 40% of the predicted value, underwent right heart catheterisation to confirm the diagnosis of PH.

Results

Eight patients (7.6%) had PH confirmed on right heart catheterisation, six patients (5.7%) had a pre-capillary pattern and two patients (1.9%) had a post-capillary profile. Only one patient (1%) had mean PAP over 35 mmHg. Patients with PH had lower FEV₁ and DL_CO in PFTs and greater oxygen desaturation and dyspnea intensity during 6MWT compared with those without PH. In 63% of the patients with confirmed PH, the right heart catheterisation was performed based only on DL_CO result.

Conclusions

The prevalence of PH is low in LAM patients. Pulmonary hypertension in LAM is typically mild and significantly associated with pulmonary parenchymal involvement. Carbon monoxide diffusion capacity significantly improved the identification of PH in LAM patients.

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

PURPOSE

This study aimed to identify the relationship between pulmonary vascular capacitance (PVC) and vasoreactivity in patients with idiopathic pulmonary arterial hypertension (IPAH), and the value of PVC in predicting long-term response to CCB treatment.

METHODS

Pulmonary vasodilator testing with inhaling iloprost was performed in 308 newly diagnosed IPAH patients. Acute vasodilator-responsive patients accepted CCBs treatment. Patients who benefit from long-term CCB were defined as those being in World Health Organization (WHO) functional class II or I after at least 1 year on CCB monotherapy.

RESULTS

PVC had significant correlations with WHO function class, 6-min walk distance, mean pulmonary arterial pressure, and pulmonary vascular resistance (r = -0.363, p < 0.001; r = 0.333, p < 0.001; r = -0.514, p < 0.001; r = -0.739, p < 0.001). Thirty-five acute vasodilator-responsive IPAH patients (11.4 %) displayed less severe disease and a higher baseline PVC (1.5 ± 0.6 vs. 1.1 ± 0.7 ml/mmHg, p = 0.003). During acute vasodilator testing, PVC increased significantly by mean of 79 ± 48 % and reached to a higher absolute value of 2.6 ± 1.5 ml/mmHg compared with non-responsive patients (1.4 ± 1.5 ml/mmHg, p < 0.001). Furthermore, PVC increased more during acute vasodilator testing in the 24 patients who benefit from long-term CCB treatment (1.4 ± 1.3 vs. 0.5 ± 0.4 ml/mmHg, p = 0.004). The OR of increased PVC during vasodilator testing for predicting patients with long-term response to CCB was 1.24 (95 % CI 1.02-1.50, p = 0.031) as assessed by multivariable logistic regression analysis.

CONCLUSIONS

PVC was higher in acute vasodilator-responsive IPAH patients and may be a predictor of long-term response to CCBs therapy.

Role of Vasodilator Testing in Pulmonary Hypertension

Pulmonary hypertension is clinically defined by a mean pulmonary artery (PA) pressure of 25mm Hg or more at rest, as measured by right heart catheterization. To identify patients who are likely to have a beneficial response to calcium channel blockers (CCBs) and therefore a better prognosis, acute vasodilator testing should be performed in patients in certain subsets of pulmonary arterial hypertension (PAH). A near normalization of pulmonary hemodynamics is needed before patients can be considered for therapy with CCBs. Intravenous adenosine, intravenous epoprostenol, inhaled nitric oxide, or inhaled iloprost are the standard agents used for vasoreactivity testing in patients with idiopathic PAH. In this review we describe the various aspects of vasodilator testing including the rationale, pathophysiology and agents used in the procedure.

Left ventricular dysfunction in patients with suspected pulmonary arterial hypertension

OBJECTIVE:

To evaluate the role of right heart catheterization in the diagnosis of pulmonary arterial hypertension (PAH).

METHODS:

We evaluated clinical, functional, and hemodynamic data from all patients who underwent right heart catheterization because of diagnostic suspicion of PAH-in the absence of severe left ventricular dysfunction (LVD), significant changes in pulmonary function tests, and ventilation/perfusion lung scintigraphy findings consistent with chronic pulmonary thromboembolism-between 2008 and 2013 at our facility.

RESULTS:

During the study period, 384 patients underwent diagnostic cardiac catheterization at our facility. Pulmonary hypertension (PH) was confirmed in 302 patients (78.6%). The mean age of those patients was 48.7 years. The patients without PH showed better hemodynamic profiles and lower levels of B-type natriuretic peptide. Nevertheless, 13.8% of the patients without PH were categorized as New York Heart Association functional class III or IV. Of the 218 patients who met the inclusion criteria, 40 (18.3%) and 178 (81.7%) were diagnosed with PH associated with LVD (PH-LVD) and with PAH, respectively. The patients in the HP-LVD group were significantly older than were those in the PAH group (p < 0.0001).

CONCLUSIONS:

The proportional difference between the PAH and PH-LVD groups was quite significant, considering the absence of echocardiographic signs suggestive of severe LVD during the pre-catheterization investigation. Our results highlight the fundamental role of cardiac catheterization in the diagnosis of PAH, especially in older patients, in whom the prevalence of LVD that has gone undiagnosed by non-invasive tests is particularly relevant.

Selectins and platelet-derived growth factor (PDGF) in schistosomiasis-associated pulmonary hypertension

PURPOSE

The aim of this study was to evaluate the expression profiles of the relevant selectins and PDGF in schistosomiasis-associated pulmonary hypertension.

METHODOLOGY

Patients with three distinct clinical profiles were enrolled in the study: IPAH(n = 11), schistosomiasis-associated PH (Sch-PH))(n = 13), and schistosomiasis without PH (Sch) (n = 13). Healthy volunteers, were recruited as a control group(n = 13). Echocardiography was performed in all groups, and the PH patients underwent right heart catheterization. Plasma soluble adhesion molecules E- and P-Selectin, PDGF-AB, PDGF-BB were determined by ELISA.

RESULTS

E-selectin was significantly increased in the IPAH group compared with the other groups [the control, Sch + PH and Sch groups) (p < 0.001) (Fig. 2)]. P-selectin was lower in Sch (20.2 + 8.9 × 103 pg/mL) as compared to the control, (43 16.8 × 103 pg/mL), IPAH (35.8 7.8 × 103 pg/mL), and Sch + PH (36.8 ± 15.7 × 103 pg/mL) (p = 0.005) groups. Serum PDGF-BB levels were higher in the control group (8.9 ± 4.8 × 103 pg/mL) compared with the IPAH (3.7 ± 2.17 × 103 pg/mL), Sch + PH (5.2 ± 3.7 × 103 pg/mL) and Sch (2.4 ± 1.7 × 103 pg/mL) groups (p < 0.05). PDGF-AB levels were also higher in the control group (25.6 ± 8.6 × 103 pg/mL), compared with the other three groups, being the Sch group the one with lower serum levels of this marker (11.4 ± 8.6 × 103 pg/mL) (p = 0.006).

CONCLUSIONS

In conclusion, vascular inflammation in schistosomiasis, with or without PH, is different from IPAH suggesting distinct pathophysiological mechanisms associated with the development of pulmonary hypertension.

Quality of life as a prognostic marker in pulmonary arterial hypertension

Background

Improvement in quality of life together with better survival are the ultimate goals in the treatment of pulmonary arterial hypertension (PAH) patients. The objective of this study was to evaluate the health-related quality of life (HRQL) of pulmonary arterial hypertension (PAH) patients with the SF-36 generic questionnaire and to identify the prognostic implication of this assessment.

Methods

Fifty-four consecutive newly diagnosed PAH patients (WHO classification group I) in a single PAH reference center were included. Patients were evaluated at baseline for clinical and hemodynamic parameters, and they subsequently received first-line therapy with either an endothelin receptor antagonist or a phosphodiesterase-5 inhibitor. After 16 weeks of specific PAH therapy, all patients were re-evaluated using a 6MWT and a SF 36 questionnaire, and then they were followed up for at least 36 months.

Results

After treatment, the patients demonstrated an improved 6MWT (414 ± 124 m vs. 440 ± 113 m, p = 0.001). Specific PAH therapy also improved the HRQL scores.

Patients with a baseline Physical Component Score (PCS) higher than 32 had a better survival rate than those who had a score under 32 (p = 0.04). Similarly, patients with a PCS of at least a 38 after the 16 week therapy period had a better survival rate when compared with those who did not achieve this value (p = 0.016). Unlike the absolute PCS values, the post-treatment PCS variability was unable to predict better survival rates (p = 0.58).

Conclusions

Our findings suggest that HRQL is associated with prognosis in PAH. Furthermore, achieving pre-determined PCS scores might represent a specific goal to be reached in treatment-to-target strategies.

Dihydropyridine Ca(2+) channel blockers increase cytosolic [Ca(2+)] by activating Ca(2+)-sensing receptors in pulmonary arterial smooth muscle cells

RATIONALE

An increase in cytosolic free Ca(2+) concentration ([Ca(2+)](cyt)) in pulmonary arterial smooth muscle cells (PASMC) is a major trigger for pulmonary vasoconstriction and an important stimulus for PASMC proliferation and pulmonary vascular remodeling. The dihydropyridine Ca(2+) channel blockers, such as nifedipine, have been used for treatment of idiopathic pulmonary arterial hypertension (IPAH).

OBJECTIVE

Our previous study demonstrated that the Ca(2+)-sensing receptor (CaSR) was upregulated and the extracellular Ca(2+)-induced increase in [Ca(2+)](cyt) was enhanced in PASMC from patients with IPAH and animals with experimental pulmonary hypertension. Here, we report that the dihydropyridines (eg, nifedipine) increase [Ca(2+)](cyt) by activating CaSR in PASMC from IPAH patients (in which CaSR is upregulated), but not in normal PASMC.

METHODS AND RESULTS

The nifedipine-mediated increase in [Ca(2+)](cyt) in IPAH-PASMC was concentration dependent with a half maximal effective concentration of 0.20 µmol/L. Knockdown of CaSR with siRNA in IPAH-PASMC significantly inhibited the nifedipine-induced increase in [Ca(2+)](cyt), whereas overexpression of CaSR in normal PASMC conferred the nifedipine-induced rise in [Ca(2+)](cyt). Other dihydropyridines, nicardipine and Bay K8644, had similar augmenting effects on the CaSR-mediated increase in [Ca(2+)](cyt) in IPAH-PASMC; however, the nondihydropyridine blockers, such as diltiazem and verapamil, had no effect on the CaSR-mediated rise in [Ca(2+)](cyt).

CONCLUSIONS

The dihydropyridine derivatives increase [Ca(2+)](cyt) by potentiating the activity of CaSR in PASMC independently of their blocking (or activating) effect on Ca(2+) channels; therefore, it is possible that the use of dihydropyridine Ca(2+) channel blockers (eg, nifedipine) to treat IPAH patients with upregulated CaSR in PASMC may exacerbate pulmonary hypertension.

Assessment of pulmonary hypertension in the pediatric catheterization laboratory: current insights from the Magic registry

OBJECTIVES

To assess protocols, demographics, and hemodynamics in pediatric patients undergoing catheterization for pulmonary hypertension (PH).

BACKGROUND

Pediatric specific data is limited on PH.

METHODS

Review of the Mid-Atlantic Group of Interventional Cardiology (MAGIC) collaboration PH registry dataset.

RESULTS

Between November 2003 and October 2008, seven institutions submitted data from 177 initial catheterizations in pediatric patients with suspected PH. Pulmonary arterial hypertension associated with congenital heart disease (APAH-CHD) (n = 61, 34%) was more common than idiopathic PAH (IPAH) (n = 36, 20%). IPAH patients were older with higher mean pulmonary arterial pressures (mPAP) (P < 0.01). Oxygen lowered mPAP in patients with IPAH (P < 0.01) and associated PAH not related to congenital heart disease (APAH-non CHD) (P < 0.01). A synergistic effect was seen with inhaled nitric oxide (iNO) (P < 0.01). Overall 9/30 (29%) patients with IPAH and 8/48 (16%) patients with APAH-non CHD were reactive to vasodilator testing. Oxygen lowered pulmonary vascular resistance index (PVRI) in patients with APAH-CHD (P < 0.01). There was no additive effect with iNO but a subset of patients required iNO to lower PVRI below 5 WU·m(2). General anesthesia (GA) lowered systemic arterial pressure (P < 0.01) with no difference between GA and procedural sedation on mPAP or PVRI. Adverse events were rare (n = 7) with no procedural deaths.

CONCLUSIONS

Pediatric patients with PH demonstrate a higher incidence of APAH-CHD and neonatal specific disorders compared to adults. Pediatric PH patients may demonstrate baseline mPAP < 40 mm Hg but > 50% systemic illustrating the difficulty in applying adult criteria to children with PH. Catheterization in children with PH is relatively safe.

Survival in schistosomiasis-associated pulmonary arterial hypertension

OBJECTIVES

The objective of this study was to evaluate the natural history of untreated schistosomiasis-associated pulmonary arterial hypertension (Sch-PAH) patients as compared to idiopathic pulmonary arterial hypertension (IPAH) with respect to hemodynamics recorded at presentation and 36 months survival.

BACKGROUND

Schistosomiasis (Sch) is one of the most prevalent chronic infectious diseases in the world. Nevertheless data regarding one of its most severe clinical complications, pulmonary arterial hypertension (PAH), is scarce.

METHODS

We retrospectively analyzed case notes of all consecutive patients diagnosed of Sch-PAH and IPAH referred to the Heart Institute in São Paulo, Brazil, between 2004 and 2008. None of the Sch-PAH received PAH specific treatment whereas all IPAH patients did.

RESULTS

Sch-PH patients (n = 54) had less severe pulmonary hypertension as evidenced by lower levels of pulmonary vascular resistance (11.3 +/- 11.3 W vs. 16.7 +/- 10.6 W; p = 0.002) and mean pulmonary artery pressure (56.7 +/- 18.7 mm Hg vs. 64.6 +/- 17.4 mm Hg; p = 0.01) and higher cardiac output (4.62 +/- 1.5 l/min vs. 3.87 +/- 1.5 l/min; p = 0.009) at presentation than IPAH patients (n = 95). None of the Sch-PAH patients demonstrated a positive response to acute vasodilator testing, whereas 16.2% of IPAH patients did (p = 0.015). Survival rates at 1, 2, and 3 years were 95.1%, 95.1%, and 85.9% and 95%, 86%, and 82%, for Sch-PAH and IPAH, respectively (p = 0.49). Both groups had a higher survival rate when compared to IPAH survival as estimated by the NIH equation (71%, 61%, and 52%, respectively).

CONCLUSIONS

Sch-PAH has a more benign clinical course than IPAH despite a lack of demonstrable acute vasoreactivity at hemodynamic evaluation.

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.

Long-term response to calcium-channel blockers in non-idiopathic pulmonary arterial hypertension

AIMS

To assess the acute vasodilator response and long-term response to calcium-channel blockers (CCB) in pulmonary arterial hypertension (PAH) with associated conditions.

METHODS AND RESULTS

The response to acute vasodilator testing [>20% decrease in mean pulmonary artery pressure (mPAP) and total pulmonary resistance] was assessed in 663 consecutive PAH patients with connective tissue disease (CTD; n = 168), portal hypertension (PoPH; n = 153), anorexigen use (n = 127), human immunodeficiency virus infection (HIV; n = 124), congenital heart disease (CHD; n = 50), and pulmonary veno-occlusive disease or capillary haemangiomatosis (PVOD/PCH; n = 41). An acute vasodilator response was observed in 13.4% of PAH-anorexigen patients, 12.2% of PVOD/PCH, 10.1% of CTD, 1.6% of HIV, 1.3% of PoPH, and was absent in CHD. A long-term response to CCB (marked haemodynamic improvement at 3-4 months and New York Heart Association functional class I or II after 1 year) was reported in 9.4% of PAH-anorexigen patients but was rare in HIV, PoPH, CTD (1.6, 0.7, and 0.6%, respectively) and absent in PVOD/PCH. All patients with a long-term CCB response were alive after 5 years; two deaths not related to PAH occurred after this time. Recent criteria for acute response based on the fall in mPAP to <40 mmHg are more specific to detect long-term responders to CCB.

CONCLUSION

A long-term CCB response was reported in patients with PAH associated with anorexigen use, but was rare in patients with PoPH or HIV and absent in PVOD/PCH, CHD, and the vast majority of CTD. The prognosis of long-term responders was favourable and related to the underlying cause of PAH.

Clinical and haemodynamic evaluation of chronic thromboembolic pulmonary hypertension patients scheduled for pulmonary thromboendarterectomy: Is schistosomiasis hypertension an important confounding factor?

INTRODUCTION

Chronic thromboembolic pulmonary hypertension is a disease affecting approximately 4,000 people per year in the United States. The incidence rate in Brazil, however, is unknown. The estimated survival for patients with chronic thromboembolic pulmonary hypertension without treatment is approximately three years. Pulmonary thromboendarterectomy for select patients is a potentially curative procedure when correctly applied. In Brazil, the clinical and hemodynamic profiles of chronic thromboembolic pulmonary hypertension patients have yet to be described.

OBJECTIVES

To evaluate the clinical and hemodynamic characteristics of chronic thromboembolic pulmonary hypertension patients scheduled for pulmonary thromboendarterectomy in a referral center for chronic thromboembolic pulmonary hypertension treatment in Brazil.

METHODS

From December 2006 to November 2009, patients were evaluated and scheduled for pulmonary thromboendarterectomy. The subjects were classified according to gender, age and functional class and were tested for thrombofilia and brain natriuretic peptide levels.

RESULTS

Thirty-five consecutive chronic thromboembolic pulmonary hypertension patients were evaluated. Two patients tested positive for schistosomiasis, and 31 were enrolled in the study (19 female, 12 male). The majority of patients were categorized in functional classes III and IV. Hemodynamic data showed a mean pulmonary vascular resistance (PVR) of 970.8 ± 494.36 dynas·s·cm-5 and a low cardiac output of 3.378 ± 1.13 L/min. Linear regression revealed a direct relation between cardiac output and pulmonary vascular resistance. Paradoxical septal movement was strongly correlated with pulmonary vascular resistance and cardiac output (p=0.001). Brain natriuretic peptide serum levels were elevated in 19 of 27 patients.

CONCLUSIONS

In a referral center for pulmonary hypertension in Brazil, chronic thromboembolic pulmonary hypertension patients evaluated for pulmonary thromboendarterectomy had a hemodynamically severe status and had elevated brain natriuretic peptide serum levels. There was a predominance of females in our cohort, and the prevalence of hematological disorders and schistosomiasis was low (less than 10%).

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

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.

Validação de um protocolo para o teste de caminhada de seis minutos em esteira para avaliação de pacientes com hipertensão arterial pulmonar

OBJETIVO: Elaborar e validar um protocolo para teste de caminhada de seis minutos em esteira (TC6est) para a avaliação de pacientes com hipertensão arterial pulmonar (HAP). MÉTODOS: A população do estudo foi composta por 73 pacientes com HAP diagnosticados através de cateterismo cardíaco direito, com ou sem inalação de NO. Todos os pacientes realizaram um TC6 em solo e três TC6est baseados em um protocolo de incremento de velocidade pré-determinado e intercalados por um período de repouso. Os pacientes que haviam realizado o teste hemodinâmico com inalação de NO realizaram o terceiro TC6est com a inalação da mesma dose de NO utilizada durante o cateterismo. RESULTADOS: Os resultados mostraram uma correlação da distância caminhada no TC6est com os dados hemodinâmicos, assim como com a classe funcional e com a distância caminhada no solo. Além disso, a distância percorrida no TC6est apresentou uma correlação significativa com a sobrevida, confirmando, portanto, sua correlação com a gravidade da doença. A inalação de NO durante o TC6est levou a variações compatíveis com as variações hemodinâmicas frente à mesma dose de NO, sugerindo que o protocolo em questão pode refletir o efeito de intervenções terapêuticas. CONCLUSÕES: Concluímos que a distância percorrida no TC6est é um marcador funcional e prognóstico na avaliação de rotina de pacientes com HAP.

Role of cardiac magnetic resonance imaging in the management of patients with pulmonary arterial hypertension

Pulmonary arterial hypertension (PAH) is a progressive disorder characterized by abnormally elevated blood pressure of the pulmonary circulation that results, over time, from extensive vascular remodeling and increased pulmonary vascular resistance. Recent advances in magnetic resonance imaging (MRI) technology have led to the development of techniques for noninvasive assessment of cardiovascular structure and function, including hemodynamic parameters in the pulmonary circulation, which are superior in their identification of right ventricular morphologic changes. These advantages make cardiac MRI an attractive modality for following up and providing prognoses in patients with PAH. In this review, we summarize recent developments in the use of MRI for the diagnosis, assessment, and ongoing monitoring of patients with PAH. Over the coming decade, it can be anticipated that continued improvements in MRI image acquisition, spatial and temporal resolution, and analytical techniques will result in improved understanding of PAH pathophysiology, diagnosis, and prognostic variables, and will supplement, and may even replace, some of the invasive procedures currently applied routinely to the evaluation of PAH.