Vasodilator Testing Research Articles

Acute Pulmonary Vasodilator Testing With Inhaled Treprostinil in Children With Pulmonary Arterial Hypertension

Acute pulmonary vasodilator testing (AVT) is essential to determining the initial therapy for children with pulmonary arterial hypertension (PAH). This study aimed to report the initial experience with inhaled treprostinil used for AVT in children with PAH and to evaluate the hemodynamic change after inhaled treprostinil compared with inhaled nitric oxide. This prospective cohort study was designed for 13 children who underwent AVT with inhaled treprostinil or oxygen plus inhaled nitric oxide (iNO) during catheterization. Inhaled treprostinil was delivered during cardiac catheterization by adapting the Optineb ultrasonic nebulizer via either a flow-inflating bag or the manual mode of the anesthesia system. The median age of the patients was 10 years (range 4-17 years). The etiologies of PAH included idiopathic PAH and associated PAH. All the patients tolerated inhaled treprostinil without marked clinical worsening and received six or nine breaths (36 or 54 μg) of treprostinil. The median of the total treprostinil doses was 1.53 μg/kg (range 0.71-2.89 μg/kg). Inhaled treprostinil was administrated via an endotracheal tube (n = 8), anesthesia mask (n = 3), or laryngeal mask airway (n = 2). Inhaled nitric oxide (iNO) and inhaled treprostinil significantly decreased the mean pulmonary artery pressure and the pulmonary vascular resistance index compared with baseline. Three adverse events were reported after inhaled treprostinil, including cough and mild to moderate hypotension with higher doses. All adverse events resolved without any intervention. This study report is the first to describe the use of inhaled treprostinil for AVT in children with PAH. In this small pediatric cohort, inhaled treprostinil was effectively delivered and well tolerated and may be useful for AVT.

Abstract 18354: Cardiac Magnetic Resonance Allows Noninvasive and Accurate Monitoring of Serial Changes in Pulmonary Vascular Resistance and the Acute Vasodilator Response in Chronic Pulmonary Hypertension

Background: Monitoring pulmonary vascular resistance (PVR) during the follow-up of patients with pulmonary hypertension (PH) and the acute vasodilator response require invasive right heart catheterization. A noninvasive method would be valuable. Hypothesis: Cardiac magnetic resonance (CMR) allows noninvasive monitoring of PVR and the acute vasodilator response. Methods: Two experimental models of chronic PH were developed in pigs. A precapillary PH model was induced by repeated pulmonary embolization with microspheres (n=8). A postcapillary PH model was generated with surgical banding of the main pulmonary vein (n=10). At baseline and every month, animals were evaluated by CMR (pulmonary artery mean flow velocity [PAvel] from phase-contrast images) with simultaneous invasive quantification of PVR using a CMR-compatible Swan-Ganz catheter (N=60 pairs of measurements). Generalized estimating equations analysis was used to correlate repeated measurements of PVR and PAvel. Additionally, correlation between acute changes in PAvel and PVR induced by pulmonary embolization (n=10) or vasodilator administration (n=10) inside the magnet was assessed using Spearman correlation. Results: Both models generated chronic PH (mPAP=30.8±4.8 and 54.5±12.8, pre and postcapillary respectively) with typical changes on pathology. CMR-model based on PAvel strongly correlated with serial measurements of PVR in both precapillary (r=0.86, p<0.01) and postcapillary (r=0.97, p<0.01, examples in figure A) models. Additionally, acute changes in PAvel were strongly correlated with the increase in PVR induced by acute embolization (r=-0.98, p<0.001, figure B) or the fall in PVR produced by vasodilator testing (r=-0.89, p<0.001, figure C). Conclusions: CMR allows noninvasive and accurate monitoring of acute and chronic changes in PVR and the acute vasodilator response in a broad spectrum of PH. This may be very valuable for the evaluation and follow-up of patients with PH.

Effects of chronic sildenafil use on pulmonary hemodynamics and clinical outcomes in heart transplantation

Elevated pulmonary vascular resistance (PVR) in heart transplant (HT) candidates is associated with poor survival after HT. This study assessed the effect of peri-operative sildenafil administration on pulmonary hemodynamics and clinical outcomes in patients with advanced heart failure who were considered high-risk for HT because of elevated PVR and transpulmonary gradient (TPG). The study included 119 consecutive patients who underwent HT between 2004 and 2011. Fifteen patients (Group A) had severe pulmonary hypertension (PH), defined as mean pulmonary pressure (MPAP)>25 mm Hg and PVR>2.5 Wood units (WU), and/or TPG>12 mm Hg after vasodilator test or the continuous administration of inotropics drugs, and 104 patients (Group B) were without severe PH. Group A received sildenafil therapy. Pulmonary hemodynamics were evaluated before HT with and without sildenafil therapy. Right catheterization was performed early after HT with sildenafil therapy and late after HT without sildenafil. Survival after HT was compared between the groups. The sildenafil dosage was 109±42 mg/day during 163±116 days before HT. After sildenafil therapy MPAP, PVR, and TPG decreased from 43.9±12.5 to 33.4±5.8 mm Hg, 5.0±1.1 to 3.0±1.6 WU, and 17.3±3.2 to 10.2±4.1 mm Hg, respectively (p<.01). All patients underwent successful HT. Sildenafil dosage was 140±70 mg/day for 43±45 days after HT. There were no differences in PVR and TPG with sildenafil therapy early after HT and without sildenafil 6 months after HT. Survival after HT was similar between the groups. Sildenafil therapy before and after HT in patients with severe PH is associated with improved pulmonary hemodynamics and successful HT, without an increase in post-HT mortality.

Safety and Clinical Relevance of Acute Vasodilator Testing in Patients With HFpEF

Safety and Clinical Relevance of Acute Vasodilator Testing in Patients With HFpEF

Perfil hemodinâmico de gravidade ao teste de vasorreatividade pulmonar em esquistossomóticos

The pulmonary vasoreactivity rate of Schistosomal Pulmonary Artery Hypertension (SPAH) is not known. Hemodynamic data obtained by cardiac catheterization are associated with the most commonly used clinical criteria of severity. To estimate the percentage of positive vasoreactivity to nitric oxide in schistosomal pulmonary arterial hypertension and verify the association of hemodynamic parameters with WHO functional classification and the six-minute walk test in these patients. A total of 84 patients with schistosomal pulmonary hypertension were selected from a database, who had been submitted to the right and left cardiac catheterization and pulmonary vasoreactivity test with nitric oxide. Data on WHO functional classification and six-minute walk test were collected for comparison with invasive data. Of the 84 patients with SPAH, 3 (3.5%) had positive criteria for pulmonary vasoreactivity. The increase in pulmonary vascular resistance was significantly associated with lower exercise capacity measured by the six-minute walk test (p = 0.045) and greater symptom severity by higher functional classifications (WHO class III/IV) (p = 0.013). The decrease in oxygen saturation in the pulmonary artery was significantly associated with higher functional classifications (p = 0.041). The pulmonary response rate to the vasodilation test of schistosomiasis patients is below the values found for idiopathic pulmonary hypertension. Pulmonary vascular resistance and oxygen saturation in the pulmonary artery are hemodynamic data that can be used as markers of severity in schistosomal pulmonary hypertension.

Mechanism of the experimental antithrombotic effect of some apple varieties involves enhanced endogenous thrombolytic activity

Abstract Prevention of arterial thrombotic diseases has high priority in developed countries. As inappropriate diet is known to enhance the risk for acute thrombotic events, a regular diet with experimentally proven antithrombotic effect might be a beneficial way of prevention. The present study is part of a series of investigations testing fruits and vegetables for antithrombotic activity. The Global Thrombosis Test was used to screen sixteen different apple varieties for antiplatelet and thrombolytic activities. The in vitro effective varieties were further investigated using the laser-induced thrombosis model in mice. In order to investigate the mechanism, hemostatometry and flow-mediated vasodilation test (FMV) were performed. Apple varieties were grouped into subclasses according to their antithrombotic activity. AP-2, AP-13, AP-14 and AP-15 showed significant antithrombotic effect both in vitro and in vivo. AP-8 was antithrombotic in vitro but could not determine in vivo because of the shortage of the sample. The antithrombotic effect was mainly due to activation of endogenous thrombolytic mechanism. The mechanism of such enhanced thrombolysis was investigated using a synthetic inhibitor highly specific to plasmin, polyclonal IgG to t-PA and u-PA, and testing the antithrombotic effect in t-PA knockout mice. Antithrombotic activity was prevented by the synthetic plasmin inhibitor and IgG against t-PA but not against u-PA. There was no antithrombotic activity in t-PA knockout mice. Intake of antithrombotic apple filtrate did not affect FMV and platelet reactivity. The antithrombotic effect was heat stable at 100 °C for 10 min. These results suggest that the mechanism of antithrombotic activity involves an increased t-PA release from the vascular endothelium and an inhibition of plasminogen activator inhibitor (PAI-1) release from activated platelets. The present findings justify including antithrombotic apple varieties in an antithrombotic diet.

2012 American college of cardiology foundation/society for cardiovascular angiography and interventions expert consensus document on cardiac catheterization laboratory standards update: American college of cardiology foundation task force on expert consensus documents society of thoracic surgeons society for vascular medicine

2012 American college of cardiology foundation/society for cardiovascular angiography and interventions expert consensus document on cardiac catheterization laboratory standards update: American college of cardiology foundation task force on expert consensus documents society of thoracic surgeons society for vascular medicine

Usefulness of Intravenous Adenosine in Idiopathic Pulmonary Arterial Hypertension as a Screening Agent for Identifying Long-Term Responders to Calcium Channel Blockers

Although intravenous adenosine is recommended for acute vasodilator testing in patients with pulmonary hypertension, long-term outcomes in acute responders treated with calcium channel blockers (CCBs) who are identified by adenosine remain unknown. In this study, the value of adenosine for identifying long-term responders to CCBs was investigated in patients with idiopathic pulmonary arterial hypertension (IPAH). All acute responders were subsequently treated with high-dose CCB monotherapy, and 6-minute walk distances, hemodynamic data, and World Health Organization functional classifications were followed. Nine of 104 patients exhibited an acute response with intravenous adenosine (8.7%, 95% confidence interval 3.2 to 14.2). After 12 months of follow-up, all acute responders were still alive; however, only 6 patients showed sustained hemodynamic improvement (5.8%, 95% confidence interval 2 to 13). Three patients had failed CCB monotherapy and bosentan was added to their treatment. Mean tolerated dose of intravenous adenosine was 142 ± 49 μg/kg/min. No life-threatening adverse events were observed and only 2 patients of the nonresponders exhibited a 20% decrease in mean systemic arterial pressure. In nonresponders, 1- and 3-year survival rates were 89% and 75%, respectively. In conclusion, acute vasodilator testing with intravenous adenosine was safe and able to screen responders to CCB therapy in patients with IPAH. Long-term CCB responders accounted for about 5.8% of patients with IPAH.

Right-Heart Function Related to the Results of Acute Pulmonary Vasodilator Testing in Patients with Pulmonary Arterial Hypertension Caused by Connective Tissue Disease

Acute pulmonary vasodilator testing is important for patients with pulmonary arterial hypertension, but little is known about the predictors of response to such testing. Forty-eight patients (mean age, 41.3 ± 11.6 years; 91.7% women) with pulmonary arterial hypertension associated with connective tissue diseases who underwent right-heart catheterization and acute pulmonary vasodilator testing were prospectively recruited. Echocardiography was performed before and immediately after testing. There were 14 responders (29.2%) to acute pulmonary vasodilator testing. Responders had lower pulmonary vascular resistance, higher peak systolic velocity of the lateral tricuspid valve annulus (right ventricular [RV] S') and tricuspid annular plane systolic excursion, and smaller RV end-diastolic area. After vasodilator testing, mean pulmonary artery pressure and pulmonary vascular resistance decreased significantly in both groups, cardiac index increased significantly in responders, and RV function improved significantly in nonresponders. Receiver operating characteristic curve analysis identified an optimal cutoff value for RV S' of ≥10.5 cm/sec to predict response, with sensitivity of 71% and specificity of 71%. There were more responders among patients with RV S' ≥ 10.5 cm/sec (45.5% vs 15.4%, P = .02). On multivariate logistic regression analysis, RV S' ≥ 10.5cm/sec emerged as an independent predictor of response (odds ratio, 4.58; 95% confidence interval, 1.18-17.79; P = .02). Right-heart function is better in responders to acute pulmonary vasodilator testing than in nonresponders among patients with pulmonary arterial hypertension associated with connective tissue diseases, and pulmonary vasodilators may improve RV function in nonresponders and cardiac index in responders. RV S' is a simple and clinically useful tool for predicting the results of pulmonary vasodilator testing.

Association of lipoprotein-associated phospholipase A2 and endothelial function in the Multi-Ethnic Study of Atherosclerosis (MESA)

Mechanisms underlying the role of lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) in atherosclerotic development are not completely understood. We evaluated the relationship of Lp-PLA(2) with endothelial dysfunction, an early manifestation of atherosclerosis, in a cohort without known clinical cardiovascular disease. A total of 2809 participants in the Multi-Ethnic Study of Atherosclerosis underwent plasma Lp-PLA(2) mass and activity measurement and brachial artery flow-mediated vasodilation testing. In adjusted linear regression models, higher Lp-PLA(2) mass and activity levels were not associated with lower endothelial function (-0.04%, p = 0.51 and -0.09%, p = 0.10, respectively). Among individuals with subclinical atherosclerosis based on ankle-brachial index (ABI) or carotid intima-media thickness (IMT), Lp-PLA(2) mass and activity were not associated with lower endothelial function (-0.03%, p = 0.88 and -0.31%, p = 0.16 for ABI < 1.00; 0.01%, p = 0.94 and -0.15%, p = 0.20 for abnormal carotid IMT). In summary, Lp-PLA(2) is not associated with endothelial dysfunction, suggesting its role in atherosclerosis development is primarily related to other factors.

Age effect on vascular reactivity in Type 1 diabetes

The objective of this study was to assess the effect of age on vascular reactivity in patients with Type 1 diabetes. Forty-five patients with Type 1 diabetes and 71 healthy control subjects, divided into three age groups (18-30, 31-45 and 46-60 years old), underwent assessment of vascular reactivity based on ultrasound examination of a brachial artery after nitric oxide donor administration. The vasodilative and haemodynamic effect was most pronounced in the youngest control subjects, where lumen widening of 0.51 ± 0.16 mm (13.9 ± 4.2%) and increase in early velocity of 28.4 ± 6.5 cm/s (237 ± 55%) were observed, while, in the control subjects from the middle and oldest age groups, the increase in artery diameter was 0.4 ± 0.11 and 0.22 ± 0.12 mm (9.8 ± 2.6 and 5.0 ± 2.6%), respectively. In the youngest patients with diabetes, lumen widening by 0.35 ± 0.13 mm (8.6 ± 3.4%) and increase in early diastolic velocity by 16.9 ± 5.6 cm/s (158 ± 52%) were noted (P < 0.05 vs. control subjects). In patients with diabetes from the middle and oldest age groups, the increase in artery diameter was 0.26 ± 0.06 and 0.16 ± 0.09 mm (5.5 ± 1.4 and 3.2 ± 1.8%), respectively. Vascular reactivity is strongly age dependent in all subjects; however, responses are delayed and occur over a longer time period in the patients with diabetes. Vasodilation test protocols should take into account the age of the subjects.

Vasoreactivity to Inhaled Nitric Oxide with Oxygen Predicts Long‐Term Survival in Pulmonary Arterial Hypertension

Pulmonary vasodilator testing is currently used to guide management of patients with pulmonary arterial hypertension (PAH). However, the utility of the pulmonary vascular response to inhaled nitric oxide (NO) and oxygen in predicting survival has not been established. Eighty patients with WHO Group I PAH underwent vasodilator testing with inhaled NO (80 ppm with 90% O2 for 10 minutes) at the time of diagnosis. Changes in right atrial (RA) pressure, mean pulmonary artery pressure (mPAP), pulmonary capillary wedge pressure, Fick cardiac output, and pulmonary vascular resistance (PVR) were tested for associations to long-term survival (median follow-up 2.4 years). Five-year survival was 56%. Baseline PVR (mean±SD 850±580 dyne-sec/cm5) and mPAP (49±14 mmHg) did not predict survival, whereas the change in either PVR or mPAP while breathing NO and O2 was predictive. Patients with a ≥30% reduction in PVR with inhaled NO and O2 had a 53% relative reduction in mortality (Cox hazard ratio 0.47, 95% confidence interval (CI) 0.23-0.99, P=0.047), and those with a ≥12% reduction in mPAP with inhaled NO and O2 had a 55% relative reduction in mortality (hazard ratio 0.45, 95% CI 0.22-0.96, P=0.038). The same vasoreactive thresholds predicted survival in the subset of patients who never were treated with calcium channel antagonists (n=66). Multivariate analysis showed that decreases in PVR and mPAP with inhaled NO and O2 were independent predictors of survival. Reduction in PVR or mPAP during short-term administration of inhaled NO and O2 predicts survival in PAH patients.

Heart transplantation in children with markedly elevated pulmonary vascular resistance: Impact of right ventricular failure on outcome

Pulmonary hypertension causes increased morbidity and mortality in adults after heart transplantation. The effect of markedly elevated pulmonary vascular resistance (PVR) on post-transplant outcomes in children has not been well described. Outcomes were compared in a retrospective study between 58 children with an elevated PVR index (PVRI) ≥ 6 U/m(2) and 205 children with a PVRI < 6 U/m(2). Patients who did and did not respond to acute vasodilator testing and patients who underwent transplant before (pre-1995) and after (post-1995) the availability of inhaled nitric oxide (iNO) were compared. The pre-transplant diagnoses, and cardiopulmonary bypass and donor ischemic times were similar between the high and low PVRI groups. High PVRI patients were older at transplant (12 ± 6.2 vs 8 ± 7.1 years, p = 0.002). The post-transplant inotrope score was higher in the high PVRI group (12 ± 12 vs 2 ± 2, p = 0.0001) and 1-year survival was worse (76% vs 81%, p = 0.03). The PVRI fell to < 6 U/m(2) with acute vasodilator testing in 21 of 49 (42%) high PVRI patients. RV failure occurred in 4 (19%) of the responders and in 14 (50%) of the non-responders (p = 0.037). One responder (5%) and 4 non-responders (14%) died of RV failure. In the period after 1995, the year iNO became clinically available, the select group of high PVRI patients who received iNO preemptively had a lower incidence of post-transplant RV failure than the group that did not receive preemptive iNO (13% vs 54%, p = 0.04). Pre-transplant vasodilator testing identified patients at higher risk for RV failure. Patients who did not respond to vasodilator testing had an increased incidence of RV failure and death from RV failure. Preemptive use of iNO was associated with a decreased incidence of RV failure.

295 Pulmonary arterial hypertension after bone marrow transplantation in children

Pulmonary arterial hypertension (PAH) is a rare but devastating complication of bone marrow transplantation (BMT). It has been reported after BMT for malignant disease or immune deficiencies. Over a period of 10 years, all children with PAH after BMT were reviewed for underlying disease, pre-BMT conditioning, associated hepatic veno-occlusive disease, characteristics of PAH, management of PAH and outcome. 14 patients were diagnosed to have PAH after BMT (mean age 8.5 months, mean age at BMT 5.7 months). The underlying disease was an immune deficiency in 11 cases and a malignant disease in 3 cases. Eleven patients received chemoprophylaxis before BMT and conditioning was the same in all cases. Seven patients had a hepatic veno-occlusive disease before the onset of PAH. PAH appeared 40 days after BMT (4–96 days). The presenting symptom was dyspnea in 13 cases and syncope in 1 case. Extensive microbiological investigations were negative in all patients. PAH was diagnosed on echocardiography in all cases and confirmed by right heart catheterization in 7 cases. All patients had normal wedge pressure. Acute vasodilation testing with NO˚ was positive in 4/14. Histology was performed in 1/14 patient and showed arteriolar lesions. Six/14 patients needed mechanical ventilation, 12/14 received specific therapies for PAH. Five patients died. PAH resolved in the remaining 9 patients after a follow-up of 3 months. All the survivors had a favourable haematological issue. PAH after BMT is a rare complication that occurs mainly in infants less than 2 years of age. It is inconstantly preceded by hepatic veno-occlusive disease. Mortality is high but reversibility is constant in survivors suggesting that an aggressive treatment should be early proposed.

The Maze of Vasodilator Response Criteria

With great interest we read the article of Barst et al. [1]. We agree with their statement that the definition of a positive acute vasodilator response in patients with pulmonary arterial hypertension (PAH) remains controversial. We believe it is very important to minimize this controversy and use uniform criteria when studying the acute pulmonary vasodilator response in patients with PAH. In their article, Barst and coworkers defined acute response criteria based on a 20% or more decrease in mean pulmonary arterial pressure (mPAP) with no decrease in cardiac index, or on a 25% or more decrease in the pulmonary vascular resistance index (PVRI) with no decrease in cardiac index (the latter only in case of an unrestricted shunt at the ventricular or ductal level). We do not recognise these criteria from previously published reports. A review of the literature provides the following definitions of a positive response to acute pulmonary vasodilator tests: An mPAP decrease of 20% or more, no decrease in cardiac index and no change or a decrease in the pulmonary-to-systemic vascular resistance ratio [2, 3] A decrease of more than 20% in both mPAP and PVRI [4, 6] A fall in total pulmonary resistance of more than 30% [7] A decrease in mPAP of 10 mmHg or more, reaching an mPAP of 40 mmHg or less and a normal cardiac output [5]. To our knowledge, the criteria used in the current article have not been published previously. The use of different response criteria in different studies results in different prevalences of acute vasodilator response and different predictive values for identifying long-term responders to calcium-channel blocker treatment and patients with improved survival [5]. Furthermore, as a result, data from these studies cannot be compared directly. For example, the prevalence of acute responders among children with PAH (42%) is reported to be higher than among adults (12–26%) [2, 4, 5]. However, because the criteria used differed between children and adults, this comparison does not hold. We commend Barst and coworkers for their success in comparing the use of different vasodilating agents (inhaled nitric oxide, oxygen, or the combination of the two) for vasodilator testing in children. However, the introduction again of new response criteria prohibits interpretation of these data in the perspective of previously published data. It is not our intention to discourage the quest for new response criteria aimed at reaching better prediction of treatment effect or survival or at expanding its use to broader patient populations other than those with idiopathic PAH (iPAH) or familial PAH (FPAH). However, in view of the ongoing discussion on the optimal definition of acute response criteria, we strongly advocate presenting the use of new criteria in a manner comparative with the use of previously published criteria.

Head-to-head comparison of first-pass MR perfusion imaging during adenosine and high-dose dobutamine/atropine stress

To directly compare the stressor capabilities of adenosine and high-dose dobutamine/atropine using first pass myocardial perfusion magnetic resonance imaging. Fourty-one patients with suspected or known coronary artery disease underwent cardiac magnetic resonance (CMR) perfusion imaging at 1.5Tesla on two consecutive days prior to invasive coronary angiography. On day 1 a standard CMR perfusion protocol during adenosine stress was carried out (adenosine infusion with 140μg/kg/min, 0.1mmol/kg Gd-DTPA). On day 2, the identical CMR perfusion sequence was repeated during a standard high-dose dobutamine/atropine stress protocol at rest and during target heart rate (85% of maximum age-predicted heart rate). Stress-inducible perfusion deficits were evaluated visually regarding presence and transmural extent. Quantitative coronary angiography served as the reference standard with significant stenosis defined as ≥50% luminal diameter reduction. Twenty-five patients (61%) had significant coronary stenoses. Adenosine and dobutamine stress CMR perfusion imaging resulted in an equally high sensitivity and specificity for the stenosis detection on a per patient basis (92 and 75% for both stressors, respectively). Agreement of both stressors with regard to the presence or absence of stress-inducible perfusion deficits was nearly perfect using patient- and segment based analysis (kappa 1.0 and 0.92, respectively). Adenosine and dobutamine/atropine stress CMR perfusion imaging are equally capable to identify stress inducible deficits and resulted in an almost identical extent of ischemic reactions. Though adenosine stress CMR perfusion imaging is widely employed, dobutamine stress CMR perfusion represents a valid alternative and may be particularly useful in patients with contraindications to vasodilator testing.

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

To assess protocols, demographics, and hemodynamics in pediatric patients undergoing catheterization for pulmonary hypertension (PH). Pediatric specific data is limited on PH. Review of the Mid-Atlantic Group of Interventional Cardiology (MAGIC) collaboration PH registry dataset. 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. 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.

Comparison of Prognostic Predictors Among Nonresponders: Vasoreactivity Testing in Pulmonary Artery Hypertension

PURPOSE: Right heart catheterization (RHC) with vasoreactivity testing using short acting agents is performed toidentify vasodilator responsive Pulmonary artery hypertension (PAH) cases that may benefit fromlong term calcium channel blocker therapy. Conflicting evidence exists regarding the value of apositive pulmonary vasodilator test to predict better survival. This study is the first of its kind tocompare the prognostic predictors among PAH patients who do not respond to vasodilator challengeduring RHC.

Survival in Schistosomiasis-Associated Pulmonary Arterial Hypertension

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. 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. 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. 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). 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

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. 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. 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%. 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.