Impact of postoperative pulmonary hypertension on outcome after heart transplantation

Multiparametric assessment of right ventricular function in heart transplant recipients by echocardiography and relations with pulmonary hemodynamics

OBJECTIVE

Right ventricular (RV) dilatation and dysfunction are usually present in heart transplant (HTx) patients and worsened with residual pulmonary hypertension (PH). We aimed to determine the ability of different echocardiographic modalities to evaluate RV function in comparison with cardiac magnetic resonance (CMR) and their relations with pulmonary hemodynamics in HTx patients.

METHODS

A total of 62 data sets [echocardiographic, hemodynamic, and CMR] were acquired from 35 HTx patients. Comprehensive echocardiography, including two-dimensional (2D) transthoracic echocardiography, speckle tracking echocardiography, and three-dimensional (3D) echocardiography, was performed. Mean pulmonary artery pressure (mPAP) was obtained invasively from right heart catheterization. The correlations between all echocardiographic parameters and CMR imaging data and the differences between patients with and without residual PH were evaluated.

RESULTS

Diastolic and systolic RV volumes and RV ejection fraction (RVEF) by 3D echocardiography correlated strongly with CMR-derived volumes and RVEF (r = .91, r = .79, r = .64; p < .0001 for each, respectively). Among other parameters, RV fractional area change (r = .439; p < .001) and RV free wall longitudinal strain (RVFW-LS) (r = -.34; p < .05) correlated moderately with CMR-RVEF, whereas tricuspid annulus S' velocity (r = .29; p < .05) and tricuspid annular systolic plane excursion (r = .27; p < .05) correlated weakly with CMR-RVEF. Additionally, 3D-RVEF and RVFW-LS were significantly decreased in studies with mPAP ≥ 20 mm Hg in comparison to those with mPAP < 20 mm Hg (47.7 ± 3.7 vs. 50.9 ± 5.3, p = .04 and -15.5 ± 3.1 vs. -17.5 ± 3, p = .03, respectively).

CONCLUSION

The best method for the evaluation of RV function in HTx recipients is 3D echocardiography. Besides, the subclinical impact of residual PH on RV function can be best determined by RVFW-LS and 3D-RVEF in these patients.

Thirty-year trends and outcome of isolated versus combined group 2 pulmonary hypertension after cardiac transplantation

Aim

To investigate the effect of the new definition of pulmonary hypertension (PH) and new pulmonary vascular resistance (PVR) thresholds on the prevalence, clinical characteristics, and events following cardiac transplantation (CTx) over 30 years.

Methods

Patients who underwent CTx between 1983 and 2014 for whom invasive hemodynamic data was available were analyzed (n = 342). Patients transplanted between 1983 and 1998 were classified as early era and those transplanted between 1999 and 2014 were classified as recent era. Group 2 PH was diagnosed in the presence of a mean pulmonary artery pressure (mPAP) &gt; 20 mmHg and pulmonary capillary wedge pressure (PCWP) &gt; 15 mmHg. Isolated post capillary PH (Ipc-PH) was defined as PVR ≤ 2 wood units and combined pre and post capillary PH (Cpc-PH) was defined PVR &gt; 2 wood units. Moderate to severe PH was defined as mPAP ≥ 35 mmHg. The primary outcome was 30-day mortality and long-term mortality according to type and severity of PH. Proportions were analyzed using the chi-square test, and survival analyses were performed using Kaplan-Meier curves and compared using the logrank test.

Results

The prevalence of PH in patients transplanted in the early era was 89.1%, whilst 84.2% of patients transplanted in the recent era had PH (p = 0.3914). There was no difference in the prevalence of a pre-capillary component according to era (p = 0.4001), but severe PH was more common in the early era (51.1% [early] vs 38.0% [recent] p = 0.0151). Thirty-day and long-term  mortality  were  not  significantly  associated  with severity or type of PH. There was a trend toward increased 30-day mortality in mild PH (10.1%), compared to no PH (4.4%) and moderate to severe PH (6.6%; p = 0.0653). Long-term mortality did not differ according to the severity of PH (p = 0.1480). There were no significant differences in 30-day or long-term mortality in IpcPH compared to CpcPH (p = 0.3974 vs p = 0.5767, respectively).

Conclusion

Over 30 years, PH has remained very prevalent before CTx. The presence, severity, and type (pre- vs post-capillary) of PH is not significantly associated with short- or long-term mortality.

Impact of bridging with left ventricular assist device on right ventricular function following heart transplantation

Aims

Patients awaiting orthotopic heart transplantation (OHT) can be bridged utilizing a left ventricular assist device (LVAD) that reduces left ventricular filling pressures, decreases pulmonary artery wedge pressure, and maintains adequate cardiac output. This study set out to examine the poorly investigated area of if and how pre‐treatment with LVAD impacts right ventricular (RV) function following OHT.

Methods and results

We prospectively evaluated 59 (LVAD n = 20) consecutive OHT patients. Transthoracic echocardiography (TTE) was performed in conjunction with right heart catheterization (RHC) at 1, 6, and 12 months after OHT. RV function TTE‐parameters included tricuspid annular plane systolic excursion (TAPSE), systolic tissue velocity (S′), fractional area change, two‐dimensional RV global longitudinal strain and longitudinal strain from the RV lateral wall (RVfree). At 1 month after OHT, the LVAD group had significantly better longitudinal RV function than the non‐LVAD group: TAPSE (15 ± 3 mm vs. 12 ± 2 mm, P < 0.001), RV global longitudinal strain (−19.8 ± 2.1% vs. −14.3 ± 2.8%, P < 0.001), and RVfree (−19.8 ± 2.3% vs. −14.1 ± 2.9%, P < 0.001). At this time point, pulmonary vascular resistance (PVR) was also lower [1.2 ± 0.4 Wood Units (WU) vs. 1.6 ± 0.6 WU, P < 0.05] in the LVAD group compared with the non‐LVAD group. At 6 and 12 months, no difference was detected in any of the TTE and RHC measured parameters between the two groups. Between 1 and 12 months, all parameters of RV function improved significantly in the non‐LVAD group but remained unaltered in the LVAD group.

Conclusions

Our results indicate that pre‐treatment with LVAD decreases PVR and is associated with significantly better RV function early following OHT. During the first year following transplantation, RV function progressively improved in the non‐LVAD group such that at 6 and 12 months, no difference in RV function was detected between the groups.

The Role of Serial Right Heart Catheterization Survey in Patients Awaiting Heart Transplant on Ventricular Assist Device

Current guidelines recommend serial right heart catheterization (RHC) to survey pulmonary hypertension in patients awaiting heart transplant. However, the role and impact of this surveillance is unclear in patients with a left ventricular assist device (LVAD). We reviewed our surveillance RHC protocol to determine whether useful data were obtained to justify the risks of serial invasive procedures (i.e., excessive bleeding). Between January 2015 and December 2018, 78 patients who received an LVAD as bridge-to-transplant (BTT) were included in this study. Routine RHC surveillance was performed every 6 months. Hemodynamic variables were retrospectively collected and reviewed. In 78 patients, 205 RHCs were analyzed. Median patient age was 54 years (IQR 46-61), and 64 (82%) were male. Thirty-six patients (46%) had pulmonary vascular resistance (PVR) ≤ 3 Wood units (WUs), and 42 patients (54%) had PVR > 3 WUs before LVAD. After LVAD implantation, mean PVR decreased by 36% from 3.8 ± 2.1 to 2.4 ± 1.1 WUs (p < 0.001) at 6 months and stabilized below 3 WUs at all post-LVAD time points. Four patients (11%) with pre-LVAD PVR ≤ 3 and 16 patients (38%) with a pre-LVAD PVR > 3 had PVR > 3 at least once during RHC survey. Of the 56 (76%) transplanted patients, six (40%) of 15 patients with a post-LVAD PVR >3 at least once developed moderate-to-severe right ventricular dysfunction. Although PVR significantly decreased after LVAD implant, PVR values fluctuated, particularly for those with pre-LVAD PVR > 3.0 WUs. Routine RHC appears valid for all BTT patients.

How does severe functional mitral regurgitation redefined by European guidelines affect pulmonary vascular resistance and hemodynamics in heart transplant candidates?

OBJECTIVE

Increased pulmonary artery pressure (PAP) and pulmonary vascular resistance (PVR) are important prognostic factors in patients with heart transplantation (HT). It is well known that severe mitral regurgitation increases pulmonary pressures. However, the European Society of Cardiology and the 6th World Symposium of pulmonary hypertension (PH) task force redefined severe functional mitral regurgitation (FMR) and PH, respectively. We aimed to investigate the effect of severe FMR on PAP and PVR based on these major redefinitions in patients with HT.

METHODS

A total of 212 patients with HT were divided into 2 groups: those with severe FMR (n=70) and without severe FMR (n=142). Severe FMR was defined as effective orifice regurgitation area ≥20 mm2 and regurgitation volume ≥30 mL where the mitral valve was morphologically normal. A mean PAP of >20 mm Hg was accepted as PH. Patients with left ventricular ejection fraction ≤25% were included in the study.

RESULTS

The systolic PAP, mean PAP, and PVR were higher in patients with severe FMR than in those without severe FMR [58.5 (48.0-70.2) versus 45.0 (36.0-64.0), p<0.001; 38.0 (30.2-46.6) versus 31.0 (23.0-39.5), p=0.004; 4.0 (2.3-6.8) versus 2.6 (1.2-4.3), p=0.001, respectively]. Univariate analysis revealed that the severe FMR is a risk factor for PVR ≥3 and 5 WU [odds ratio (OR): 2.0, 95% confidence interval (CI): 1.1-3.6, p=0.009; and OR: 3.2, 95% CI: 1.5-6.7, p=0.002]. The multivariate regression analysis results revealed that presence of severe FMR is an independent risk factor for PVR ≥3 WU and presence of combined pre-post-capillary PH (OR: 2.23, 95% CI: 1.30-3.82, p=0.003 and OR: 2.30, 95% CI: 1.25-4.26, p=0.008).

CONCLUSION

Even in the updated definition of FMR with a lower threshold, severe FMR is associated with higher PVR, systolic PAP, and mean PAP and appears to have an unfavorable effect on pulmonary hemodynamics in patients with HT.

Alterations in plasma L-arginine and methylarginines in heart failure and after heart transplantation

OBJECTIVE

Endothelial function, including the nitric oxide (NO)-pathway, has previously been extensively investigated in heart failure (HF). In contrast, studies are lacking on the NO pathway after heart transplantation (HT). We therefore investigated substances in the NO pathway prior to and after HT in relation to hemodynamic parameters.

DESIGN

12 patients (median age 50.0 yrs, 2 females), heart transplanted between June 2012 and February 2014, evaluated at our hemodynamic lab, at rest, prior to HT, as well as four weeks and six months after HT were included. All patients had normal left ventricular function post-operatively and none had post-operative pulmonary hypertension or acute cellular rejection requiring therapy at the evaluations. Plasma concentrations of ADMA, SDMA, L-Arginine, L-Ornithine and L-Citrulline were analyzed at each evaluation.

RESULTS

In comparison to controls, the plasma L-Arginine concentration was low and ADMA high in HF patients, resulting in low L-Arginine/ADMA-ratio pre-HT. Already four weeks after HT L-Arginine was normalized whereas ADMA remained high. Consequently the L-Arginine/ADMA-ratio improved, but did not normalize. The biomarkers remained unchanged at the six-month evaluation and the L-Arginine/ADMA-ratio correlated inversely to pulmonary vascular resistance (PVR) six months post-HT.

CONCLUSIONS

Plasma L-Arginine concentrations normalize after HT. However, as ADMA is unchanged, the L-Arginine/ADMA-ratio remained low and correlated inversely to PVR. Together these findings suggest that (i) the L-Arginine/ADMA-ratio may be an indicator of pulmonary vascular tone after HT, and that (ii) NO-dependent endothelial function is partly restored after HT. Considering the good postoperative outcome, the biomarker levels may be considered "normal" after HT.

Posttransplant Pulmonary Hypertension Is Correlated With Acute Rejection and Death Among Cardiac Transplant Recipients: A Single Center Study

OBJECTIVES

Endomyocardial biopsy sampling is used to check acute rejection after cardiac transplant. However, it may lead to tricuspid valve injury and cardiac perforation; therefore, less invasive tools may be useful. Right heart catheterization provides valuable information about cardiac hemodynamics. Herein, we aimed to determine the correlation of right heart catheterization parameters with acute rejection and death during cardiac transplant follow-up.

MATERIALS AND METHODS

We retrospectively evaluated follow-up right heart catheterization and endomyocardial biopsy results from 47 adult patients who underwent cardiac transplant at Başkent University Faculty of Medicine between 2004 and 2016. Right heart catheterization parameters were compared between deceased and surviving patients and were correlated with acute cellular and humoral rejection. Averaged right heart catheterization parameters were correlated with death. We used Cox regression analysis to determine risk of death and acute cellular rejection and Kaplan-Meier survival analysis to determine any survival differences associated with pulmonary hypertension.

RESULTS

There were 47 patients (38 males, 9 females) with a mean age of 44 ± 10 years at transplant. In our patient group, 18 patients (38.3%) died at a median time of 11.2 months. Ninety endomyocardial biopsy samples (22.1%) showed cellular rejection, and 61 samples (4.5%) showed humoral rejection. The deceased patients had significantly greater mean and systolic pulmonary artery pressures, which were significantly correlated with acute cellular rejection. Death was significantly correlated with averaged values of mean and systolic pulmonary artery pressures. Our Cox regression analysis revealed that pulmonary hypertension was significantly associated with risk of death and acute cellular rejection. A Kaplan-Meier survival analysis revealed that pulmonary hypertension was associated with a significantly lower median survival.

CONCLUSIONS

Pulmonary artery pressures are significantly correlated with acute cellular rejection and death after cardiac transplant. Pulmonary hypertension significantly increases the risk of death and shortens survival after cardiac transplant.

SLC28A3 rs7853758 as a new biomarker of tacrolimus elimination and new-onset hypertension in Chinese liver transplantation patients

AIM

The effect of SLC28A3 on tacrolimus disposition and new-onset hypertension (NOHP) after liver transplantation (LT) remains unclear. Methodology & results: A total of 169 patients in two cohorts from the China Liver Transplant Registry database were included. Rs7853758 in recipients'SLC28A3 could predict tacrolimus pharmacokinetics in two sets. The model of donors' CYP3A5 rs776746 and recipients' CYP3A4 rs2242480 could predict tacrolimus metabolism at week 1 and the model of donors' CYP3A5 rs776746, recipients' CYP3A4 rs2242480, recipients' SLC28A3 rs7853758 and hemoglobin could predict tacrolimus disposition at weeks 2, 3 and 4. Besides, recipients' SLC28A3 rs7853758 was a new risk factor of NOHP after LT.

CONCLUSION

Rs7853758 in recipients' SLC28A3 has a correlation with tacrolimus pharmacokinetics and the risk of NOHP in Chinese LT patients.