Evaluation of pulmonary hypertension in heart transplant candidates

Pulmonary hypertension: Hemodynamic evaluation. Updated Recommendations of the Cologne Consensus Conference 2011

The 2009 European Guidelines on Diagnosis and Treatment of Pulmonary Hypertension have been adopted for Germany. The guidelines contain detailed recommendations for the diagnosis of pulmonary hypertension. However, the practical implementation of the European Guidelines in Germany requires the consideration of several country-specific issues and already existing novel data. This requires a detailed commentary to the guidelines, and in some aspects an update already appears necessary. In June 2010, a Consensus Conference organized by the PH working groups of the German Society of Cardiology (DGK), the German Society of Respiratory Medicine (DGP) and the German Society of Pediatric Cardiology (DGPK) was held in Cologne, Germany. This conference aimed to solve practical and controversial issues surrounding the implementation of the European Guidelines in Germany. To this end, a number of working groups was initiated, one of which was specifically dedicated to the invasive hemodynamic evaluation of pulmonary hypertension. This manuscript describes in detail the results and recommendations of the working group which were last updated in October 2011.

Heart failure in women

Heart failure (HF) has steadily increased in prevalence and affects both males and females equally. Despite this, there has been a significant underrepresentation of women in large scale HF trials. This disparity has lead to a deficit in understanding important gender-based differences in pathophysiology, diagnosis and treatment strategies. We review these gaps and explore a biological basis for varying outcomes. Endogenous estrogen plays an important role in epidemiology and outcome. The administration of exogenous estrogen has had varied success in treatment and is outlined extensively below. Additionally, we highlight unique HF syndromes through pregnancy and important sex-specific issues concerning transplant and mechanical circulatory support. A central theme remains: there is a clear need for increased female recruitment in clinical trials, and more studies exploring the role of gender-based biology in HF treatment.

Initial Experience with Sildenafil, Bosentan, and Nitric Oxide for Pediatric Cardiomyopathy Patients with Elevated Pulmonary Vascular Resistance before and after Orthotopic Heart Transplantation

Background. Although pulmonary hypertension complicating dilated cardiomyopathy has been shown to be a significant risk factor for graft failure after heart transplantation, the upper limits of pulmonary vascular resistance (PVR) that would contraindicate pediatric heart transplantation are not known. Methods. A retrospective review of all pediatric orthotopic heart transplant (OHT) performed at our institution from 2002 to 2007 was performed. Seven patients with PVR > 6 Wood's units (WU) prior to transplant were compared pre- and postoperatively with 20 matched controls with PVR < 6 WU. All pulmonary vasodilator therapies used are described as well as outcomes during the first year posttransplant. Results. The mean PVR prior to transplantation in the 7 study cases was 11.0 ± 4.6 (range 6–22) WU, compared to mean PVR of 3.07 ± 0.9 WU (0.56–4.5) in the controls (P = .27 × 10⁻⁶). All patients with elevated PVR were treated pre-OHT with either Sildenafil or Bosentan. Post-OHT, case patients received a combination of sildenafil, iloprost, and inhaled nitric oxide. All 7 case patients survived one year post-OHT, and there was no statistical difference between cases and controls for hospital stay, rejection/readmissions, or graft right ventricular failure. Mean PVR in the cases at one and three months post-OHT was not significantly different between the two groups. Only one of the cases required prolonged treatment with iloprost after OHT. Conclusions. A PVR above 6 WU should not be an absolute contraindication to heart transplantation in children.

[Pulmonary hypertension and heart failure: the role of pulmonary vasculature]

Left heart disease is the most common cause of pulmonary hypertension. Increased left-sided filling pressure leads to passive postcapillary venous hypertension. In some patients, pulmonary vasoconstriction and vascular remodeling may lead to a further increase in pulmonary pressure. When precapillary hypertension component is associated to left heart failure, the elevation of pulmonary pressure is out of proportion with left atrial pressure: transpulmonary gradient greater than 12 mmHg (mean pulmonary pressure -- mean capillary pressure) and pulmonary vascular resistance greater than three Wood units. Precapillary pulmonary hypertension is common in severe systolic heart failure. Before cardiac transplantation, increased pulmonary vascular resistance greater than 3,5 Wood units are reported in 19 to 35% of patients. In those patients vasoreactivity tests are performed with inotropic and/or systemic and/or pulmonary agents to determine the risk of right heart failure after transplantation. There is no pulmonary vascular resistance level above which transplantation is contraindicated. Cardiac assistance may be used before and after transplantation when pulmonary hypertension is severe and not reversible with conventional treatment and/or pulmonary vasodilators. The contribution of precapillary PH in diastolic heart failure is not known but can be significant and lead to disproportionate PH particularly in elderly. The precapillary component of pulmonary hypertension could be a therapeutic target for specific pulmonary vasodilators. Until now pharmacological trials has been disappointing and those medications can be dangerous because of increasing blood flow to the pulmonary capillaries with a risk of pulmonary edema when left sided pressure are still elevated.

Pulmonary hypertension secondary to left ventricular systolic dysfunction: contemporary diagnosis and management

Pulmonary hypertension secondary to left ventricular systolic dysfunction is often a poor prognostic marker in chronic heart failure. In this article, we review evidence supporting modern strategies addressing pulmonary hypertension in patients with left ventricular systolic dysfunction, including right-sided heart catheterization with vasoreactivity testing and subsequent parenteral, oral, and inhaled therapy. We delineate a diagnostic approach to secondary pulmonary hypertension and outline evidence-based therapeutic strategies for management in acute and chronic heart failure.

Right ventricular failure complicating heart failure: pathophysiology, significance, and management strategies

Right heart failure most commonly results from the complication of left heart failure (systolic or nonsystolic dysfunction) or pulmonary hypertension. Over the past decade, greater attention has been paid to the role of right ventricular failure in the morbidity and mortality associated with cardiomyopathy and pulmonary hypertension. The right ventricle is distinct from the left ventricle not only in its spatial localization, but also in its response to increased afterload and signaling mechanisms. This article discusses the role of right ventricular failure in the setting of heart failure as well as the clinical diagnosis and management of right ventricular failure.

Medically Refractory Pulmonary Hypertension: Treatment With Nonpulsatile Left Ventricular Assist Devices

BACKGROUND

Severe pulmonary hypertension refractory to medical treatment is a contraindication to orthotopic heart transplantation in most centers. We report our experience in treating severe pulmonary hypertension with mechanical left ventricular unloading using implantable nonpulsatile left ventricular assist devices (LVAD) with continuous flow properties.

METHODS

In ten patients with severe pulmonary hypertension, refractory to medical treatment, an implantable nonpulsatile LVAD was placed for continuous mechanical left ventricular support. Pulmonary hemodynamics were assessed by right heart catheterization prior to and during LVAD implantation, and after orthotopic heart transplantation.

RESULTS

The mean (+/-SD) interval of nonpulsatile support was 182 (+/-118) days. Pulmonary artery pressure (mean +/- SD) significantly decreased from 42 +/- 13 to 24 +/- 5 mm Hg (p < 0.005), the transpulmonary gradient (mean +/- SD) decreased from 20 +/- 6 to 11 +/-5 mm Hg (p < 0.005), and the pulmonary vascular resistance (mean +/- SD) from 4.8 +/- 1.8 to 2.2 +/- 0.8 Wood units (p < 0.005) during an interval of one to six months of LVAD support. No significant increases in pulmonary artery pressure, transpulmonary gradient, and pulmonary vascular resistance were observed during an interval of three to six months after orthotopic heart transplantation.

CONCLUSIONS

This study supports that LVAD support and continuous nonpulsatile mechanical unloading of the left ventricle can reverse medically unresponsive pulmonary hypertension and render patients eligible for orthotopic heart transplantation.

Effect of Reversible Pulmonary Hypertension on Outcomes After Heart Transplantation

BACKGROUND

Conflicting data exist regarding the impact of reversible pulmonary hypertension (PHTN) on post-transplant (Tx) outcomes. In this study we sought to determine the influence of reversible PHTN on outcomes after Tx.

METHODS

We retrospectively reviewed the records of adult patients who underwent heart Tx from 1993 to 2002. Patients were grouped depending on their measured pulmonary vascular resistance (PVR). Group 1 patients had a pre-Tx pulmonary vascular resistance (PVR) of < 3 Wood units (WU). Patients with reversible PHTN, defined as pre-Tx PVR > or = 3 WU and reversing to < 3 WU either with sub-lingual or intravenous vasodilatory agents, were divided into two groups based on their PVR before the reversibility test (PVR: Group 2, 3 to 4.5 WU; Group 3, > 4.5 WU).

RESULTS

Records for 222 adult heart recipients were reviewed (Group 1, n = 171; Group 2, n = 35; Group 3, n = 16). Baseline clinical characteristics (age, gender, heart failure etiology, history of diabetes, ischemic time, donor age and gender) were similar in the three groups and the average follow-up was 58 months. One-month and 1-year mortality (Groups 1, 2 and 3: 2%, 0% and 13%; and 8%, 0% and 13%, respectively) did not differ significantly between groups. Actuarial mortality was assessed using Cox regression analysis, adjusted for age and gender, and no increased risk of death was demonstrated for patients with reversible PHTN (for Group 2: multivariate hazard ratio [HR] 0.45, 95% confidence interval [CI] 0.17 to 1.32, p = 0.15; for Group 3: HR 0.98, CI 0.34 to 2.84, p = 0.97). No differences were observed between the three groups for various post-Tx events, such as hospital stay, ICU stay, extubation time, transfusions, acute allograft dysfunction, acute hepatic dysfunction, acute and chronic renal dysfunction, infections, neurologic complications, gastrointestinal complications and coronary allograft vasculopathy.

CONCLUSIONS

Reversible pulmonary hypertension is associated with similarly good post-transplant survival outcomes and morbidity, regardless of severity.

Evaluation of pulmonary vascular response to inhaled iloprost in heart transplant candidates with pulmonary venous hypertension

OBJECTIVE

Chronic left-heart failure is often associated with the development of pulmonary venous hypertension. In heart transplant candidates this is of great significance because the healthy donor heart has to compensate the increased right-ventricular afterload. Right-ventricular dysfunction is still responsible for 19% of all early deaths after orthotopic heart transplantation. Careful preoperative assessment of pulmonary vascular resistance by right-heart catheterization is essential. Reversibility testing is generally carried out to clarify therapeutic options for the post-transplant period. The objective of this case series is to report our institutional experience with inhaled iloprost compared to the common used oxygen/nitroglycerin method for reversibility testing.

METHODS

Right-heart catheterization was performed in 23 patients with severely impaired left-ventricular function (EF < or = 25%, pVO2 < or = 14 ml/kg/min, NYHA III or IV) with combined pulmonary venous hypertension (TPG > 12 mm Hg and or PVR > 250 dyn x s x cm(-5)). An intraindividual comparison was performed between of the hemodynamic effect with oxygen/nitroglycerin s.l. and inhaled iloprost.

RESULTS

The transpulmonary gradient fell significantly from an initial 16 mm Hg to 13 mm Hg on oxygen/nitroglycerin s.l. compared to 10 mm Hg on inhaled iloprost. Pulmonary vascular resistance fell significantly from an initial 344 dyn x s x cm(-5) to 270 dyn x s x cm(-5) on oxygen/nitroglycerin s.l. compared to 209 dyn x s x cm(-5) on inhaled iloprost. On inhaled iloprost a moderate systemic effect was noticed.

CONCLUSION

In heart transplant candidates with pulmonary venous hypertension reversibility testing with inhalation of iloprost is a save method and significantly more effective than the combination of inhaled oxygen plus nitroglycerin s.l.

Inhaled nitric oxide through a noninvasive ventilation device to assess reversibility of pulmonary hypertension in selecting recipients for heart transplant

INTRODUCTION

Pulmonary hypertension (PHT) is an independent risk factor for right ventricular failure and death after heart transplant. Nitric oxide (NO) is a powerful and selective vasodilator, indicated in this scenario, but its response is unpredictable. Thus, it should be assessed prior to the intervention. However, preoperative assessment has not been widespread due to its difficulties and risks.

OBJECTIVE

We describe herein a pulmonary vasodilatory test with NO administered through a noninvasive ventilation (NIMV) device. We also assessed the effect of NO in patients with severe PHT owing to cardiac disease. Assessment of the utility of the test to select patients for heart transplant.

METHODS

We enrolled 19 patients with severe PHT for a preoperative assessment for heart transplant. Thresholds used were as follows: systolic pulmonary arterial pressure (SPAP) > or =65 mm Hg, transpulmonary gradient (TPG) > or =15 mm Hg, and pulmonary vascular resistance (PVR) > or =4.5 Wood units (WU). NO was administered through a modified noninvasive ventilation device. Cardiac output and pulmonary pressures were measured simultaneously by right heart catheterization.

RESULTS

All patients agreed to be enrolled in the test. No difficulties, interruptions, or severe complications happened in any case. Basal and NO average measured values were SPAP (74.16 and 57.95 mm Hg), PVR (7.5 and 3.7 WU), and TPG (23.25 and 12.58 mm Hg). The differences were significant (P < .05) for all three tests. We consider acceptable for heart transplant a response that reduces PHT to a moderate grade. Using these criteria 14 patients were accepted and 11 underwent heart transplant. Two deaths in the postoperative period were both secondary to mediastinal bleeding and not related to right ventricular failure.

CONCLUSIONS

A pulmonary vasodilatory test with NO administered through a NIMV device was feasible and useful to select suitable heart transplant recipients with severe pulmonary hypertension.

Effects of intravenous nesiritide on pulmonary vascular hemodynamics in pulmonary hypertension

BACKGROUND

Nesiritide is effective in the treatment of decompensated heart failure (HF). We evaluated the acute hemodynamic effects of nesiritide, a recombinant B-type natriuretic peptide, in patients with HF and pulmonary hypertension (PH).

METHODS AND RESULTS

Twenty patients with HF and PH (mean pulmonary arterial [PA] pressure >25 mm Hg) were enrolled: 10 with postpulmonary capillary wedge (PCW) >15 mm Hg and 10 with precapillary PH (PCW) < or =15. The pulmonary and systemic hemodynamics were determined by right heart catheterization at baseline and at 15 and 30 minutes after an intravenous nesiritide infusion (2 mcg/kg bolus and 0.01 mcg.kg.min). For the patients with postcapillary PH, the mean left ventricular ejection fraction was 28 +/- 15%. After the 30-minute nesiritide infusion, right atrial (RA) pressure decreased 48% (P < .0001), mean PA pressure decreased 29% (P < .0001), PCW pressure decreased 40% (P < .0001), cardiac index (CI) increased 35% (P = .009), pulmonary vascular resistance index (PVRI) decreased 35% (P = .01), and arteriovenous oxygen difference (AVDO(2)) decreased 27% (P = .0003). For precapillary PH patients, there was no change in RA, PA, or PCW pressure, nor any change in CI, PVRI, or AVDO(2).

CONCLUSIONS

Nesiritide acutely and significantly reduced PA pressure, PVRI, and biventricular filling pressures in patients with postcapillary PH. However, for patients with precapillary PH, nesiritide had no significant acute hemodynamic effect on the pulmonary hemodynamics. The lack of acute beneficial effects of nesiritide in patients with advanced precapillary PH may be related to their relatively fixed remodeling of the pulmonary vasculature.

Combined Administration of Intravenous Dipyridamole and Inhaled Nitric Oxide to Assess Reversibility of Pulmonary Arterial Hypertension in Potential Cardiac Transplant Recipients

BACKGROUND

Irreversible, severe pulmonary hypertension (PH) can produce right heart failure and early mortality after cardiac transplantation. We hypothesized that dipyridamole, an inhibitor of Type 5 phosphodiesterase, would augment the ability of inhaled nitric oxide (NO) to identify reversibility of PH.

METHODS

In 9 patients with congestive heart failure (CHF) and severe PH who were breathing 100% oxygen during right heart catheterization, we administered inhaled NO (80 ppm) alone and in combination with intravenous dipyridamole (0.2-mg/kg bolus, with an infusion of 0.0375 mg/kg/min).

RESULTS

Compared with breathing oxygen alone, NO inhalation decreased pulmonary artery pressure and pulmonary vascular resistance (PVR) (by 10 +/- 4% and 26 +/- 12% [mean +/- SEM], respectively; both p < 0.05). The combination of NO and dipyridamole reduced PVR (43 +/- 7%; p < 0.05) to a greater extent than did administration of NO alone, and increased the duration of pulmonary vasodilation produced by NO inhalation. Combined administration of inhaled NO and intravenous dipyridamole increased cardiac index (by 23 +/- 10%) and reduced SVR (by 19 +/- 6%, both p < 0.05) without changing systemic arterial pressure. NO inhalation reduced PVR to <200 dyne x s/cm5 in 3 of 7 patients who had a PVR of >200 dyne x s/cm5 when breathing oxygen alone, whereas the combination of NO and dipyridamole decreased PVR to <200 dyne.s/cm(5) in 2 additional patients.

CONCLUSIONS

Intravenous dipyridamole augments and prolongs the pulmonary vasodilator effects of inhaled NO in CHF patients with severe PH and, when administered in combination with NO inhalation, can identify PH reversibility in potential cardiac transplant recipients in whom a pulmonary vasodilator response to inhalation of NO alone is not observed.

Mild vs Severe Pulmonary Hypertension Before Heart Transplantation: Different Effects on Posttransplantation Pulmonary Hypertension and Mortality

BACKGROUND

Pulmonary hypertension (PH) is common in severe heart failure, but the effect of mild PH on posttransplantation PH and survival after heart transplantation has not been well described.

METHODS

This cohort study examined preoperative and postoperative hemodynamics in 172 heart transplant recipients at Johns Hopkins Hospital followed for up to 15.1 years. PH was defined as pulmonary vascular resistance > or =2.5 Wood units, as measured during routine right heat catheterization; mild to moderate PH was defined as PVR between 2.5 and 4.9 Wood units; and severe PH was defined as PVR > or =5.0 Wood units.

RESULTS

Seventy-one patients (41.3%) had PH, mostly of mild/moderate severity (77.5%), at the last routine hemodynamic monitoring before transplantation (median time before transplantation, 2.7 months). During follow-up, 105 patients (62.9%) developed PH at some point after transplantation, and 48 patients died (cumulative incidence, 76.5%). Mild/moderate preoperative PH was associated with increased risk of posttransplantation PH at 1, 3, and 6 months, but not with later episodes of PH. Mild/moderate preoperative PH was not associated with a higher mortality rate, but each 1 Wood unit increase in preoperative PVR demonstrated a trend toward increased mortality. Severe preoperative PH was associated with death within the first year after adjusting for potential confounders, but not with overall mortality or mortality at other time points.

CONCLUSIONS

Mild to moderate preoperative PH is associated with increased risk of developing early but not late posttransplantation PH and may suggest different management strategies. Although PH was not consistently associated with mortality, increasing severity of the preoperative PH suggests potentially worse prognosis.