Pulmonary endarterectomy: technique and pitfalls.

Chronic thromboembolic pulmonary hypertension (CTEPH) remains a rare and underdiagnosed disease. After one or several episodes of acute pulmonary embolism, around 3% of patients develop CTEPH and two-thirds of these patients are potential surgical candidates. Besides surgery, additional treatment modalities are pulmonary arterial hypertension medication and balloon pulmonary angioplasty. Patients should be evaluated in CTEPH expert centers to ensure the most appropriate therapy. Pulmonary endarterectomy (PEA) is a complex, but standardized surgical procedure aiming to clear the obstructed pulmonary arteries completely. For optimal visualization, deep hypothermic circulatory arrest is a prerequisite. This article will give an overview of the evaluation, indication and surgical management of patients with CTEPH.

Exercise right heart catheterisation before and after pulmonary endarterectomy in patients with chronic thromboembolic disease.

Symptomatic patients with chronic thromboembolic disease (CTED) without pulmonary hypertension often show an excessive increase in mean pulmonary arterial pressure (MPAP) during exercise.We report on the impact of pulmonary endarterectomy (PEA) on pulmonary haemodynamics in a prospective series of 32 consecutive CTED patients who underwent PEA. All patients had a comprehensive diagnostic work-up including right heart catheterisation at baseline and 12 months after PEA. Furthermore, in 12 patients exercise right heart catheterisation was performed before and after PEA.After PEA, MPAP was lower at rest (20±3 versus 17±3 mmHg; p=0.008) and during maximal exercise (39±8 versus 31±6 mmHg; p=0.016). The mean total pulmonary resistance (TPR) decreased from 3.6±0.8 Wood Units (WU) pre-operatively to 2.7±0.7 WU 1 year after PEA (p=0.004) and the mean slope of the MPAP/cardiac output (CO) relationship decreased from 3.6±1.0 to 2.3±0.8 WU (p=0.002). Peak oxygen uptake increased from 1.2±0.4 to 1.5±0.3 L·min-1 (p=0.014) and ventilatory equivalents of carbon dioxide decreased from 39±2 to 30±2 (p=0.002). There was a significant improvement in quality of life assessed by the Cambridge Pulmonary Hypertension Outcome Review questionnaire.In CTED patients, PEA resulted in haemodynamic and clinical improvements. The means of TPR and MPAP/CO slopes decreased to <3.0 WU.

Length of pressure-controlled reperfusion is critical for reducing ischaemia-reperfusion injury in an isolated rabbit lung model.

BACKGROUND: Ischaemia-reperfusion injury is still a major problem after lung transplantation. Several reports describe the benefits of controlled graft reperfusion. In this study the role of length of the initial pressure-controlled reperfusion (PCR) was evaluated in a model of isolated, buffer-perfused rabbit lungs. METHODS: Heart-lung blocks of 25 New Zealand white rabbits were used. After measurement of baseline values (haemodynamics and gas exchange) the lungs were exposed to 120 minutes of hypoxic warm ischaemia followed by repeated measurements during reperfusion. Group A was immediately reperfused using a flow of 100 ml/min whereas groups B, C and D were initially reperfused with a maximum pressure of 5 mmHg for 5, 15 or 30 minutes, respectively. The control group had no period of ischaemia or PCR. RESULTS: Uncontrolled reperfusion (group A) caused a significant pulmonary injury with increased pulmonary artery pressures (PAP) and pulmonary vascular resistance and a decrease in oxygen partial pressure (PO2), tidal volume and in lung compliance. All groups with PCR had a significantly higher PO2 for 5 to 90 min after start of reperfusion. At 120 min there was also a significant difference between group B (264 +/- 91 mmHg) compared to groups C and D (436 +/- 87 mmHg; 562 +/- 20 mmHg, p < 0.01). All PCR groups showed a significant decrease of PAP compared to group A. CONCLUSION: Uncontrolled reperfusion results in a severe lung injury with rapid oedema formation. PCR preserves pulmonary haemodynamics and gas exchange after ischaemia and might allows for recovery of the impaired endothelial function. 30 minutes of PCR provide superior results compared to 5 or 15 minutes of PCR.

Ultrathin polymer monolayers for promotion of cell growth on bioprosthetic materials -- evolution of a new concept to improve long term performance of biologic heart vales.

Reoperation of aldehyde tanned bioprotheses due to calcific degeneration remains their major drawback. Based on experiments studying mechanisms and factors that influence the time phase, extent and progression of calcification and evaluating the efficiency of anticalcification treatments and the effects of surface seeding with vital cells a new concept to avoid calcification emerged: masking aldehyde-residues with a covalently bound polymer that supports surface cell seeding. Different covalently bound polymers were tested for their suitability to grow cells. Dense cell growth was achieved on some polymers but without correlation to physico-chemical properties. Ultrathin coating of biological materials appears a promising approach to achieve lining with vital cells.