Does preexisting elevated pulmonary vascular resistance (transpulmonary gradient > 15 mm Hg or > 5 wood) predict early and long-term results after orthotopic heart transplantation?

Elevated pre-transplant pulmonary vascular resistance is associated with early post-transplant atrial fibrillation and mortality

AIMS

Severely elevated pre-transplant pulmonary vascular resistance (PVR) has been linked to adverse effects after heart transplantation (HTX). The impact of a moderately increased PVR before HTX on post-transplant outcomes remains uncertain. The aim of this study was to investigate the effects of an elevated pre-transplant PVR ≥ 300 dyn·s·cm^-5 (≥3.75 Wood units) on outcomes after HTX.

METHODS AND RESULTS

This observational retrospective single-centre study included 561 patients receiving HTX at Heidelberg Heart Center between 1989 and 2015. Patients were stratified by degree of pre-transplant PVR. Analyses covered demographics, post-transplant medication, mortality and causes of death after HTX, early post-transplant atrial fibrillation (AF), and length of the initial hospital stay after HTX. Ninety-four patients (16.8%) had a PVR ≥ 300 dyn·s·cm^-5 (≥3.75 Wood units). These patients had a higher rate of early post-transplant AF [20.2 vs. 10.7%, difference: 9.5%, 95% confidence interval (CI): 0.9-18.1%, P = 0.01] and an increased 30 day post-transplant mortality (25.5 vs. 6.4%, hazard ratio: 4.4, 95% CI: 2.6-7.6, P < 0.01), along with a higher percentage of death due to transplant failure (21.2 vs. 4.1%, difference: 17.1%, 95% CI: 8.7-25.5%, P < 0.01). Multivariate analysis revealed a PVR ≥ 300 dyn·s·cm^-5 (≥3.75 Wood units) as a significant risk factor for increased 30 day mortality after HTX (hazard ratio: 4.4, 95% CI: 2.5-7.6, P < 0.01). Kaplan-Meier estimator showed a lower 2 year survival after HTX (P < 0.01) in patients with a PVR ≥ 300 dyn·s·cm^-5 (≥3.75 Wood units).

CONCLUSIONS

Elevated pre-transplant PVR ≥ 300 dyn·s·cm^-5 (≥3.75 Wood units) is associated with early post-transplant AF and increased mortality after HTX.

Bosentan improved persistent pulmonary hypertension in a case after implantation of a left ventricular assist device

No medical treatment has been established to ameliorate pulmonary hypertension (PH) due to left heart disease. Heart transplantation (HTx) is thus far the definitive therapy for stage D heart failure, but concomitant PH is one of the major risk factors for death after HTx. Recently, implantation of a left ventricular assist device (LVAD) has been reported to improve PH and has become a major bridge tool for HTx. We experienced a rare case with persistent PH even after the implantation of a continuous-flow LVAD. The administration of an endothelin receptor antagonist, bosentan, significantly decreased pulmonary vascular resistance. Combination therapy with LVAD implantation and anti-PH medication may be useful for patients with stage D heart failure complicated with severe PH.

Predictors of pulmonary hypertension in patients with end-stage heart failure

Pulmonary hypertension (PH) is associated with a greater mortality rate in patients with heart failure (HF) and it is a risk factor for right ventricular failure after heart transplantation. This study was designed to explore risk factors for PH development in patients with advanced heart failure and left ventricular dysfunction. In a retrospective observational study of 419 patients evaluated for heart transplantation due to end stage HF, different variables were analyzed to find predictors of PH (defined as a mean pulmonary pressure >25 mmHg), reactive PH (defined as a transpulmonary gradient >12 mmHg) and severe PH (defined as a mean pulmonary pressure >40 mmHg and/or pulmonary vascular ressistance >3 WU) using a multivariate stepwise logistic regression analysis. Prevalence of PH, out of proportion and severe PH was 62.2%, 23.8%, and 18.8% respectively. The presence of moderate-severe mitral regurgitation [2.1 (1.2-3.7); P=0.006], moderate-severe tricuspid regurgitation [OR 2.9 (1.3-6.4); P=0.005] and a duration of disease >3 years [OR 1.7 (1.1-2.7); P=0.03] were independent risk factors associated with PH. Moreover, the presence of a moderate-severe mitral regurgitation and a duration of disease greater than 3 years, were independent predictors of out of proportion and severe PH.

Is Severe Pulmonary Hypertension a Contraindication for Orthotopic Heart Transplantation? Not Any More

Pulmonary hypertension (PH) unresponsive to pharmacological intervention is considered a contraindication for orthotopic heart transplantation (OHTX) due to risk of postoperative right-heart failure. In this prospective study, we describe our experience with a treatment strategy of improving severe PH in heart transplant candidates by means of ventricular assist device (VAD) implantation and subsequent OHTX. In 11 heart transplantation candidates with severe PH unresponsive to pharmacological intervention we implanted VAD with the aim of achieving PH to values acceptable for OHTX. In all patients we observed significant drop in pulmonary pressures, PVR and TPG (p<0.001 for all) 3 months after VAD implantation to values sufficient to allow OHTX. Seven patients underwent transplantation (mean duration of support 216 days) while none of patients suffered right-side heart failure in postoperative period. Two patients died after transplantation and five patients are living in very good condition with a mean duration of 286 days after OHTX. In our opinion, severe PH is not a contraindication for orthotopic heart transplantation any more.

Pulsatile left ventricular assist device support as a bridge to decision in patients with end-stage heart failure complicated by pulmonary hypertension

BACKGROUND

Severe pulmonary hypertension (PH) in heart failure (HF) is a risk factor for adverse outcomes after heart transplantation (HTx). Left ventricular assist devices (LVADs) improve pulmonary hemodynamics, but our understanding of the degree of improvement and the effect on outcomes is still evolving.

METHODS

We reviewed invasive pulmonary hemodynamics from 58 consecutive patients receiving LVAD support as a bridge to HTx from 1996 to 2003. The primary outcome was change in baseline transpulmonary gradient (TPG) during LVAD support and after HTx/recovery. The secondary outcome was post-HTx survival.

RESULTS

All patients (age, 49 +/- 14 years, 79% male, 40% ischemic) received a pulsatile LVAD (median support, 97 days; interquartile range [IQR], 31-222). Hemodynamic measurements were obtained at baseline (median, 1 day; IQR, 1-3), during early (median, 1 day; IQR, 0-4) and late (median, 75 days; IQR, 24-186) LVAD support, and after HTx/recovery (median, 28 days; IQR, 17-40). Improvement in TPG occurred throughout LVAD support and was sustained after HTx/recovery. Levels of TPG reductions in patients with a baseline TPG in the highest quartile (14.1-26.0 mm Hg) were 8.6 +/- 3.5 vs 6.5 +/- 3.1 mm Hg in the lowest quartile (2.0-7.7 mm Hg) during LVAD support (p = 0.102), with 90% vs 100% 30-day post-HTx survival (P = 0.113).

CONCLUSION

Pulmonary hemodynamics and post-HTx survival were similar after pulsatile LVAD support in patients with and without pre-implant PH. LVAD support may be a useful strategy to reverse PH in carefully selected patients, thus improving candidacy for HTx.

Pulmonary hypertension in heart failure

BACKGROUND

Pulmonary hypertension occurs in 60% to 80% of patients with heart failure and is associated with high morbidity and mortality.

METHODS AND RESULTS

Pulmonary artery pressure correlates with increased left ventricular end-diastolic pressure. Therefore, pulmonary hypertension is a common feature of heart failure with preserved as well as reduced systolic function. Pulmonary hypertension is partially reversible with normalization of cardiac filling pressures. Pulmonary vasculature remodeling and vasoconstriction create a second component, which does not reverse immediately, but has been shown to improve with vasoactive drugs and especially with left ventricular assist devices.

CONCLUSION

Many drugs used for idiopathic pulmonary arterial hypertension are being considered as treatment options for heart failure-related pulmonary hypertension. This is of particular significance in the heart transplant population. Randomized clinical trials with interventions targeting heart failure patients with elevated pulmonary artery pressure would be justified.

Pulmonary hypertension in chronic heart failure

The presence of PH in patients who suffer from CHF is common and predicts a poor outcome. However, precise definitions for PH associated with left heart disease, or 'out-of-proportion' PH as well as standardised vasodilator testing protocols are lacking. Moreover, apart from single-centre observations no large-scale trial to date has demonstrated a long-term benefit from pulmonary vasoactive drugs. As a result, there are currently no consensus recommendations for the treatment of PH in the presence of CHF. Off-label use of specific vasodilators in this patient population is discouraged. In a majority of cases, treatment of the underlying left heart disease leads to a decrease in pulmonary pressures. In light of novel agents to treat PH, trials that specifically address 'out-of-proportion' PH in CHF patients are warranted.

Noninvasive Assessment of Pulmonary Vascular Resistance Using Doppler Tissue Imaging of the Tricuspid Annulus

BACKGROUND

Pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are important hemodynamic parameters in patients with advanced cardiopulmonary disease. We undertook this study to determine whether Doppler tissue imaging of the tricuspid annulus could be used to assess PAP and PVR noninvasively.

METHODS

We studied 50 consecutive patients with suspected chronic thromboembolic pulmonary hypertension referred to our center for evaluation. We performed preoperative transthoracic echocardiography with Doppler tissue imaging of the tricuspid annulus. All patients then underwent cardiac catheterization with invasive determination of cardiac output, PAP, and PVR.

RESULTS

The systolic velocity of the tricuspid annulus (tS(m)) had an inverse relationship with catheterization-derived mean PAP, with a correlation coefficient of -0.493 (P = .0003). The inverse correlation of tS(m) with catheterization-derived PVR was more striking, with a correlation coefficient of -0.710 (P < .0001). Based on the data, we derived the following logarithmic regression equation: PVR = 3698 - 1227 x ln(tS(m)).

CONCLUSIONS

Doppler tissue imaging of the lateral tricuspid annulus is a useful clinical tool that can provide a noninvasive estimate of PVR in patients with chronic thromboembolic pulmonary hypertension. In this population, decreasing values of tS(m) predicted progressively higher measurements of PVR.

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.

Pre-existing Pulmonary Hypertension in Patients With End-stage Heart Failure: Impact on Clinical Outcome and Hemodynamic Follow-up After Orthotopic Heart Transplantation

BACKGROUND

The purpose of this investigation was to determine the influence of pre-existing pulmonary hypertension (PHT) on outcome and to assess the pulmonary hemodynamic changes after heart transplantation (HT).

METHODS

A total of 410 patients were studied before and after (1 month and 1 year) HT: Group 1 (n = 266) had no PHT (PVR < 3 Wood units [WU], TPG < 10 mm Hg); Group 2 (n = 112) had mild-moderate PHT (PVR 3 to 6 WU, TPG 10 to 20 mm Hg); and Group 3 (n = 32) had severe PHT (PVR > 6 WU, TPG > 20 mm Hg).

RESULTS

Mean (+/- SD) follow-up was 5.2 +/- 4.1 years, mean recipient age was 57 +/- 11, and mean donor age was 30 +/- 12 years. Baseline characteristics were similar in all groups, except donor/recipient weight ratio, which was higher in patients with PHT (p = 0.002). There was a significant (p < 0.0001) decrease in mean TPG to 11.0 within the first month and to 9.5 mm Hg after the first year. Decreases in PVR to 2.2 and 2.0 WU at 1 month and 1 year, respectively (p < 0.0001 for both) were also found. Reversibility (after vasodilation) of PHT was obtained in 85% of patients in Group 2 and in 84% in Group 3. Patients' PHT did not show a significant difference in 30-day mortality (p = 0.9) and long-term survival (p = 0.8). Patients with residual post-transplant PHT (PVR > or = 3 WU) had reduced long-term survival (p = 0.03). Multivariate analysis showed no evidence that elevated PVR was associated with death.

CONCLUSIONS

Pre-existing elevated PVR that responds to vasodilator challenge does not have a negative influence on short- and long-term survival after HT. We found that residual post-transplant PHT is associated with decreased long-term survival.

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.

Clinical indication for use and outcomes after inhaled nitric oxide therapy

BACKGROUND

Inhaled nitric oxide (iNO) use is widespread, but the long-term outcomes after therapy in adult patients remain unknown.

METHODS

All 376 patients receiving perioperative iNO (excluding pediatric and interventional cardiology procedures) at Columbia University Medical Center were prospectively followed from 2000 to 2003. Survival data were collected from chart review.

RESULTS

Inhaled nitric oxide was used to treat pulmonary and right ventricular failure in patients undergoing orthotopic heart transplantation (OHT, n = 67), orthotopic lung transplantation (n = 45), cardiac surgery (n = 105), and ventricular assist device placement (n = 66), and for hypoxemia in other surgery (n = 34) and medical patients (n = 59). Average follow-up was 2.9 +/- 1.0 years. Overall mortality was lowest when iNO was used after OHT (25.4%) and orthotopic lung transplantation (37.8%), intermediately after cardiac surgery (61%), ventricular assist device (62%), and other surgery patients (75%), and highest among medical patients (90%; all p < 0.005). The cost of iNO therapy was lower in transplantation versus medical patients, with a trend toward shorter duration of use. In multivariate analysis, respiratory failure and use in non-OHT were independent predictors of mortality (both p = 0.001). A risk score greater than 1 (score = non-OHT use 1, plus right ventricular failure 1) predicted a mortality of 76.5% versus 37.2% (p < 0.001).

CONCLUSIONS

Use of iNO for pulmonary hypertension in patients undergoing OHT and orthotopic lung transplantation was associated with a significantly lower overall mortality rate compared with its use after cardiac surgery or for hypoxemia in medical patients. Inhaled nitric oxide does not appear to be cost effective when treating hypoxemia in medical patients with high-risk scores and irreversible disease.

Initial experience with bosentan therapy in patients considered ineligible for heart transplantation because of severe pulmonary hypertension

BACKGROUND

Pre-operative elevated pulmonary vascular resistance (PVR) has been associated with increased right ventricular failure and mortality after heart transplantation. The aim of this study was to assess the efficacy of bosentan, an oral endothelin-receptor antagonist, to reduce PVR in patients considered ineligible for heart transplantation because of severe pulmonary hypertension.

METHODS

Seven patients with end-stage congestive heart failure and considered ineligible for heart transplantation because of severe pulmonary hypertension (PVR>2.5 Wood units after nitroprusside infusion) were included in the study. They received bosentan 62.5 mg b.i.d. for four wk and 125 mg b.i.d. thereafter. Right heart catheterization was repeated after six wk of therapy.

RESULTS

After six wk of bosentan therapy, there was a significant decrease in PVR (6.0 +/- 2 vs. 3.8 +/- 2 Wood units, before vs. after bosentan; p = 0.02), in PVR during nitroprusside infusion (3.3 +/- 1 vs. 2.1 +/- 1 Wood units, before vs. after bosentan; p = 0.02) and in diastolic pulmonary artery pressure (33 +/- 7 vs. 23 +/- 7 mmHg, before vs. after bosentan; p = 0.04). No significant adverse events were observed. After bosentan therapy, five patients had PVR<or=2.5 Wood units. They were included in the waiting list and all five had a successful heart transplantation, although two of them required bosentan after surgery.

CONCLUSIONS

In patients considered ineligible for heart transplantation because of high PVR, bosentan therapy significantly reduced PVR. These data suggest that therapy with endothelin-receptor blockers might be useful to identify a subgroup of patients with high PVR who can benefit from heart transplantation.

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.

Is the transpulmonary pressure gradient a predictor for mortality after orthotopic cardiac transplantation?

Elevated pulmonary vascular resistance (PVR) is a well-known risk factor for right ventricular failure after orthotopic cardiac transplantation. The influence of preoperative transpulmonary pressure gradient (TPG) and PVR on post-transplant 30 days mortality was evaluated. To analyze the response of PVR and TPG to cardiac transplantation, we analyzed 718 adult patients undergoing primary cardiac transplantation. Indications for operation were: 35.2% ischemic cardiomyopathy (ICM), 61.2% idiopathic dilated cardiomyopathy (DCM), and 3.3% other diagnosis (e.g. hypertrophic cardiomyopathy). The mean age (51.9) and the mean ischemic time (169.7 min) were comparable between 30 days survivors and nonsurvivors. Student's t-tests and chi-square analysis were used to compare data from 30-day survivors and nonsurvivors. Statistical significance was defined as P < 0.05. Fisher's exact test and multiple logistic regression analysis was performed to evaluate the relationship between hemodynamic parameters and outcome after transplantation. Primary end-point was 30 days mortality and secondary end-point long-term survival of patient groups with different TPG and PVR values. In survivors the mean TPG was 10.3 +/- 5.1 (mean +/- SD) vs. 13 +/- 6.6 in patients who died after transplantation (P = 0.0012). The PVR was 2.6 +/- 1.4 vs. 3.5 +/- 2.2 (P = 0.0012). In multivariate logistic regression, the parameters TPG and PVR exhibit a significant influence between survivors and nonsurvivors after cardiac transplantation within 30 days (TPG: P = 0.0012; PVR: P = 0.0012). The mortality rates in patients with TPG > 11 mmHg and PVR < 2.8 Wood units or TPG < 11 mmHg and PVR > 2.8 Wood units were comparable to those with TPG < 11 mmHg and PVR < 2.8 mmHg. The TPG is an important predictor in nonrejection-related early mortality after orthotopic cardiac transplantation. The determination of TPG in combination with PVR is a more reliable predictor of early post-transplant survival than PVR alone.

Nitric Oxide Versus Prostaglandin E1 for Reduction of Pulmonary Hypertension in Heart Transplant Candidates

BACKGROUND

We sought to directly compare the effects of prostaglandin E1 (PGE1) and nitric oxide (NO) in testing for pulmonary hypertension reversibility in heart transplant candidates.

METHODS

We included 19 heart transplant candidates who fulfilled at least 1 of 3 criteria: pulmonary vascular resistance (PVR) of >4 Wood units; transpulmonary gradient (TPG) of >12 mmHg; or systolic pulmonary artery pressure (PAP) of >60 mmHg. Patients randomly received either PGE1 (0.05, 0.2 and 0.5 microg/kg/min) or NO (40, 60 and 80 ppm) and were crossed-over to the second medication after receiving the maximal dose of the first.

RESULTS

With PGE1, TPG decreased by 21% (baseline 20.3 +/- 6.8 mmHg; final 16.0 +/- 7.0 mmHg) compared to a 34% decrease with NO (baseline 20.8 +/- 6.2 mmHg; final 13.8 +/- 5.4 mmHg) (p = 0.13). PVR decreased by 42% with PGE1 (baseline 6.2 +/- 4.0 Wood units; final 3.6 +/- 1.8 Wood units) and by 47% with NO (baseline 6.0 +/- 3.9 Wood units; final 3.2 +/- 1.6 Wood units) (p = 0.87). Mean systemic pressure decreased with PGE1 (baseline 76.1 +/- 10.5 mmHg; final 69.4 +/- 12.2 mmHg; -9%) but not with NO administration (baseline 70.2 +/- 14.7 mmHg; final 71.6 +/- 10.9 mmHg; +2%) (p = 0.01). TPG was lowered to <12 mmHg in 14 patients. Of these, 6 (46%) responded to both PGE1 and NO, 4 (27%) responded only to PGE1, and 4 (27%) responded only to NO.

CONCLUSIONS

The effects of PGE1 and NO on pulmonary hypertension are comparable, with PGE1 having more systemic hypotensive effects. Due to variability of patient responses, we recommend multiple rather than single-agent pharmacologic testing for the reversibility of pulmonary hypertension.

Pre-transplant reversible pulmonary hypertension predicts higher risk for mortality after cardiac transplantation

BACKGROUND

Pre-transplant fixed pulmonary hypertension is associated with higher post-transplant mortality. In this study, we assessed the significance of pre-transplant reversible pulmonary hypertension in patients undergoing cardiac transplantation.

METHODS

Overall, we studied 182 patients with baseline normal pulmonary pressures or reversible pulmonary hypertension, defined as a decrease in pulmonary vascular resistance (PVR) to < or =2.5 Wood units (WU), who underwent cardiac transplantation. Multiple recipient and donor characteristics were assessed to identify independent predictors of mortality.

RESULTS

The average duration of follow-up was 42 +/- 28 months. Forty patients (22%) died during the follow-up period. Baseline hemodynamics for alive vs dead patients were as follows: pulmonary artery systolic (PAS) 42 +/- 15 vs 52 +/- 15 mm Hg; PA diastolic 21 +/- 9 vs 25 +/- 9 mm Hg; PA mean 28 +/- 11 vs 35 +/- 10 mm Hg; transpulmonary gradient (TPG) 9 +/- 4 vs 11 +/- 7 mm Hg (all p < 0.05); total pulmonary resistance 7.7 +/- 4.8 vs 8.8 +/- 3.2 WU (p = 0.08); and PVR 2.3 +/- 1.5 vs 2.9 +/- 1.6 WU (p = 0.06). In an unadjusted analysis, patients with PAS >50 mm Hg had a higher risk of death (odds ratio [OR] 5.96, 95% confidence interval [CI] 1.46 to 19.84 as compared with PAS < or =30 mm Hg). There was no significant difference in survival among patients with baseline PVR <2.5, 2.5 to 4.0 or >4.0 WU, but patients with TPG > or =16 had a higher risk of mortality (OR 4.93, 95% CI 1.84 to 13.17). PAS pressure was an independent predictor of mortality (OR 1.04, 95% CI 1.02 to 1.06). Recipient body mass index, history of sternotomy; and donor ischemic time were the other independent predictors of mortality.

CONCLUSION

Pre-transplant pulmonary hypertension, even when reversible to a PVR of < or =2.5 WU, is associated with a higher mortality post-transplant.

Reversible pulmonary hypertension in heart transplant candidates-pretransplant evaluation and outcome after orthotopic heart transplantation

BACKGROUND

Heart transplantation is the most effective treatment for well-selected patients with endstage heart failure. Unfortunately, transplant candidates with pulmonary hypertension (PHT) are often not considered for heart transplantation. This study was performed to assess the value of prostaglandin E(1) (PG-E(1)) for reduction of PHT and to predict the postoperative outcome, compared to patients without PHT.

PATIENTS AND METHODS

We studied a group of 151 consecutive heart transplant candidates using right heart catheterization. In patients with PHT (pulmonary vascular resistance, PVR> or =2.5 Wood-Units (WU) and/or transpulmonary gradient (TPG)> or =12 mmHg) a short-term treatment protocol with PG-E(1) was performed, to achieve PVR<2.5 WU and TPG<12 mmHg.

RESULTS

61 patients (40%) had PHT according to our criteria. Reduction of PHT was successful in 71% of patients (n=43), of these, 18 patients underwent cardiac transplantation and the 1-year mortality rate was 22% (n=4). The 1-year mortality rate in transplanted patients without PHT was 14% (n=3). There was no statistical difference in survival between the PHT and the non-PHT group. Outcome in patients without heart transplantation was similar in both groups, except for patients with non-reducible PHT (1-year mortality 50%).

CONCLUSIONS

Our study demonstrates the efficacy and safety of PG-E(1) in lowering PHT in heart transplant candidates, as well as the need for aggressive evaluation and treatment in these patients. Patients with reversible PHT have comparable post-transplant outcomes and no tendency to higher acute right ventricular failure.

Reversibility of Medically Unresponsive Pulmonary Hypertension with Nesiritide in a Cardiac Transplant Recipient

Pulmonary hypertension unresponsive to medical therapy is considered by most centers to be a contraindication for orthotopic cardiac transplantation. This article describes a patient with unresponsive severe pulmonary hypertension who, despite a combination of maximal doses of dobutamine, milrinone, and nitroprusside infusion, responded to nesiritide (Natrecor) infusion with improvement in pulmonary hemodynamics. The patient was considered a high risk for transplantation because of significant pulmonary hypertension in spite of maximum oral therapy and continuous intravenous milrinone. Severe irreversible pulmonary hypertension persisted with a combination of dobutamine, milrinone, and nitroprusside, with pulmonary artery pressure (PA) of 88/44 mm Hg, a transpulmonary gradient (TPG) of 27, and pulmonary vascular resistance (PVR) of 5.79 Wood units. Upon addition of nesiritide, within 24 hours, there was a sustained decrease in PA to 47/30, TPG of 15, and PVR of 3.75 Wood units. The patient underwent successful left ventricular assist device placement soon after nesiritide infusion demonstrated reversibility of pulmonary hypertension. He subsequently underwent uneventful orthotopic cardiac transplantation and has done well with normal right heart pressures. This case illustrates that addition of nesiritide to standard therapy can reverse significant unresponsive pulmonary hypertension and make a patient eligible for left ventricular assist device and orthotopic cardiac transplantation.

Recipient selection in cardiac transplantation: contraindications and risk factors for mortality

Currently the only acknowledged, definitive treatment for refractory heart failure is heart transplantation (HTx). During the past 10 years, selection criteria for heart transplant recipients have been developed that use an analysis of risk factors associated with mortality, which were identified by consensus opinion and by single-center and multi-center database review. A number of other studies also have been designed to evaluate specific risk factors for transplant such as advanced age, diabetes, and sex. This review identifies variables that continue to provoke controversy during the candidate selection process or variables that have changed from absolute to relative contraindications for HTx. Clinicians may use the data summarized in this review as a guide to making decisions about patient candidacy for HTx. One could conclude from this analysis that a more formalized and objective scale to select patients and to assess risk of death after HTx is necessary. Moreover, as alternative therapies to HTx become reality, a better instrument for triaging patients to one form of therapy or another may be necessary.

The evolving management of acute right-sided heart failure in cardiac transplant recipients

Avoidance of the clinical syndrome of acute right-sided heart failure after heart transplantation is, unfortunately, not possible. Clinical experience and the literature certainly suggest that a significant factor in the successful management of right ventricular (RV) failure is recipient selection. Moreover, threshold hemodynamic values beyond which RV failure is certain to occur and heart transplantation is contraindicated do not exist. Nor are there values below which RV failure is always avoidable. Acute RV failure will remain a difficult and ever-present clinical syndrome in the transplant recipient. Goals in the treatment of this clinical problem include: 1. Preserving coronary perfusion through maintenance of systemic blood pressure. 2. Optimizing RV preload. 3. Reducing RV afterload by decreasing pulmonary vascular resistance (PVR). 4. Limiting pulmonary vasoconstriction through ventilation with high inspired oxygen concentrations (100% FiO(2)), increased tidal volume and optimal positive end expiratory pressure ventilation. Inhaled nitric oxide is recommended before leaving the operating room in cases where the initial therapies have had little impact. Intra-aortic balloon counterpulsation is employed in patients with impaired left ventricular (LV) function and may be of benefit in patients with RV dysfunction resulting from ischemia, preservation injury or reperfusion injury. Optimal LV function reduces RV afterload and PVR. A proactive decision regarding RV assist device implantation is made before leaving the operating room and is highly dependent upon overall hemodynamics, size and function of the ventricles as seen on transesophageal echocardiography, renal function and surgical bleeding. Only through careful preoperative planning can this life-threatening condition be managed in the postoperative period.