Severe left ventricular failure after double lung transplantation: pathophysiology and management

Perioperative fluid balance and early acute kidney injury after lung transplantation

BACKGROUND

Postoperative acute kidney injury (AKI) after lung transplantation (LTx) is an important factor affecting the short-term outcomes. The focus item of transplantation centers is how to improve the incidence of AKI through optimal management during the perioperative period.

OBJECTIVE

The purpose of the study is to investigate the influence of perioperative volume in the development of early AKI following LTx.

METHOD

The study involved patients who had undergone LTx between October 2018 to December 2021 at China-Japan Friendship Hospital in Beijing. The patients were monitored for AKI occurring within 72 hours after LTx, as well as the renal outcomes within 30 days. The perioperative volumes were compared and analyzed to determine the impact on various clinical outcomes.

RESULTS

248 patients were enrolled in the study ultimately, with almost half of them (49.6 %) experiencing AKI. 48.8 % of AKI patients received continuous renal replacement therapy (CRRT), with 57.7 % recovered by the end of the 30-day follow-up period. A J-shaped relationship was demonstrated between perioperative volume and AKI incidence. Moreover, maintaining a positive fluid balance would increase the 30-day mortality and lead to poor renal outcomes.

CONCLUSION

Perioperative volume is an independent risk factor of early AKI after LTx. Positive fluid balance increases the risk of AKI, 30-day mortality, and adverse renal prognosis. The LTx recipients may benefit from a relatively restrict fluid strategy during and after the lung transplantation.

Left Ventricular Dysfunction After Lung Transplantation for Pulmonary Arterial Hypertension

BACKGROUND

Lung transplantation (LT) is the final treatment option for patients with pulmonary arterial hypertension (PAH). Perioperative challenges after LT are unique and commonly include excessive bleeding, arrhythmias, and primary graft dysfunction. Transient left ventricular dysfunction (LVD) is a known postoperative complication, but not fully explored. We describe our experiences at a single institution.

METHODS

We reviewed our database for patients with PAH who underwent LT from July 2008 to July 2012. The data were analyzed for preoperative inotrope use, intravenous prostacyclin, cardiac catheterization, and imaging. Also measured were perioperative ischemic time, bypass time, primary graft dysfunction, ventilator days, length of stay, and mortality. LVD is defined as acute cardiopulmonary compromise (acute worsening of hypoxia with new bilateral infiltrates on imaging) with a drop in LV systolic function of 15% from baseline. We compared data between patients with LVD and without LVD.

RESULTS

Sixteen patients met the criteria, the majority of patients (10) with World Health Organization (WHO) group 1 PAH. Thirteen received intravenous prostacyclin therapy, and 6 required inotropes before surgery. Five patients (31%) developed LVD after transplantation. Average time to onset of LVD was 4.2 days. Preoperative vasopressors were required in 60% of those developing LVD. Patients with LVD had lower right and left ventricular ejection fraction with higher left ventricular end diastolic volume before surgery. All patients recovered from LVD within 4 months after LT.

CONCLUSIONS

LVD is a phenomenon observed mostly in patients with WHO group 1 PAH receiving LT. Prompt recognition and treatment of this condition reduced morbidity.

The striated muscles in pulmonary arterial hypertension: adaptations beyond the right ventricle

Pulmonary arterial hypertension (PAH) is a fatal lung disease characterised by progressive remodelling of the small pulmonary vessels. The daily-life activities of patients with PAH are severely limited by exertional fatigue and dyspnoea. Typically, these symptoms have been explained by right heart failure. However, an increasing number of studies reveal that the impact of the PAH reaches further than the pulmonary circulation. Striated muscles other than the right ventricle are affected in PAH, such as the left ventricle, the diaphragm and peripheral skeletal muscles. Alterations in these striated muscles are associated with exercise intolerance and reduced quality of life. In this Back to Basics article on striated muscle function in PAH, we provide insight into the pathophysiological mechanisms causing muscle dysfunction in PAH and discuss potential new therapeutic strategies to restore muscle dysfunction.

Contractile dysfunction of left ventricular cardiomyocytes in patients with pulmonary arterial hypertension

BACKGROUND

After lung transplantation, increased left ventricular (LV) filling can lead to LV failure, increasing the risk of post-operative complications and mortality. LV dysfunction in pulmonary arterial hypertension (PAH) is characterized by a reduced LV ejection fraction and impaired diastolic function.

OBJECTIVES

The pathophysiology of LV dysfunction in PAH is incompletely understood. This study sought to assess the contribution of atrophy and contractility of cardiomyocytes to LV dysfunction in PAH patients.

METHODS

LV function was assessed by cardiac magnetic resonance imaging. In addition, LV biopsies were obtained in 9 PAH patients and 10 donors. The cross-sectional area (CSA) and force-generating capacity of isolated single cardiomyocytes was investigated.

RESULTS

Magnetic resonance imaging analysis revealed a significant reduction in LV ejection fraction in PAH patients, indicating a reduction in LV contractility. The CSA of LV cardiomyocytes of PAH patients was significantly reduced (~30%), indicating LV cardiomyocyte atrophy. The maximal force-generating capacity, normalized to cardiomyocyte CSA, was significantly reduced (~25%). Also, a reduction in the number of available myosin-based cross-bridges was found to cause the contractile weakness of cardiomyocytes. This finding was supported by protein analyses, which showed an ~30% reduction in the myosin/actin ratio in cardiomyocytes from PAH patients. Finally, the phosphorylation level of sarcomeric proteins was reduced in PAH patients, which was accompanied by increased calcium sensitivity of force generation.

CONCLUSIONS

The contractile function and the CSA of LV cardiomyocytes is substantially reduced in PAH patients. We propose that these changes contribute to the reduced in vivo contractility of the LV in PAH patients.

Combining tricuspid valve repair with double lung transplantation in patients with severe pulmonary hypertension, tricuspid regurgitation, and right ventricular dysfunction

BACKGROUND

Concomitant tricuspid valve repair (TVR) and double lung transplantation (DLTx) has been a surgical option at our institution since 2004 in an attempt to improve the outcome of DLTx for end-stage pulmonary hypertension, severe tricuspid regurgitation, and right ventricle (RV) dysfunction. This study is a review of that single institutional experience.

METHODS

Consecutive cases of concomitant TVR and DLTx performed between 2004 and 2009 (TVR group, n = 20) were retrospectively compared with cases of DLTx alone for severe pulmonary hypertension without TVR (non-TVR group, n = 58).

RESULTS

There was one in-hospital death in the TVR group. The 90-day and 1- and 3-year survival rates for the TVR group were 90%, 75%, and 65%, respectively, which were not significantly different from those for the non-TVR group. The TVR group required less inotropic support and less prolonged mechanical ventilation in the ICU. Follow-up echocardiography demonstrated immediate elimination of both volume and pressure overload in the RV and tricuspid regurgitation in the TVR group. Notably, there was a significantly lower incidence of primary graft dysfunction following transplantation in the TVR group (P < .05). Pulmonary functional improvement shown by an FEV(1) increase after 6 months was also significantly better in the TVR group (40% vs 20%, P < .05).

CONCLUSIONS

Combined TVR and DLTx procedures were successfully performed without an increase in morbidity or mortality and contributed to decreased primary graft dysfunction. In our experience, this combined operative approach achieves clinical outcomes equal or superior to the outcomes seen in DLTx patients without RV dysfunction and severe tricuspid regurgitation.