Yinglong Liu

Pulmonary artery perfusion with protective solution reduces lung injury after cardiopulmonary bypass.

BACKGROUND The inflammatory response and higher temperature of lung tissue during cardiopulmonary bypass can result in lung injury. This study was to evaluate the protective effect of pulmonary perfusion with hypothermic antiinflammatory solution on lung function after cardiopulmonary bypass. METHODS Twelve adult mongrel dogs were randomly divided into two groups. The procedure was carried out through a midline sternotomy, cardiopulmonary bypass was established using cannulas placed in the ascending aorta, superior vena cava, and right atrium near the entrance of the inferior vena cava. After the ascending aorta was clamped and cardioplegic solution infused, the right lung was perfused through a cannula placed in the right pulmonary artery with 4 degrees C lactated Ringers solution in the control group (n = 6) and with 4 degrees C protective solution in the antiinflammation group (n = 6). Antiinflammatory solution consisted of anisodamine, L-arginine, aprotinin, glucose-insulin-potassium, and phosphate buffer. Plasma malondialdehyde, white blood cell counts, and lung function were measured at different time point before and after cardiopulmonary bypass; lung biopsies were also taken. RESULTS Peak airway pressure increased dramatically in the control group after cardiopulmonary bypass when compared with the antiinflammation group at four different time points (24 +/- 1, 25 +/- 2, 26 +/- 2, 27 +/- 2 cm H2O versus 17 +/- 2, 18 +/- 1, 17 +/- 1, 18 +/- 1 cm H2O; all p < 0.01). Pulmonary vascular resistance increased significantly in the control group than in the antiinflammation group at 5 and 60 minutes after cardiopulmonary bypass (1,282 +/- 62 dynes x s x cm(-5) versus 845 +/- 86 dynes x s x cm(-5) and 1,269 +/- 124 dynes x s x cm(-5) versus 852 +/- 149 dynes x s x cm(-5), p < 0.05). Right pulmonary venous oxygen tension (PvO2) in the antiinflammation group was higher than in the control group at 60 minutes after cardiopulmonary bypass (628 +/- 33.3 mm Hg versus 393 +/- 85.9 mm Hg, p < 0.05). The ratio of white blood cells in the right atrial and the right pulmonary venous blood was lower in the antiinflammation group than in the control group at 5 minutes after the clamp was removed (p < 0.05). Malondialdehyde were lower in the antiinflammation group at 5 and 90 minutes after the clamp was removed (p < 0.01 and p < 0.05, respectively). Histologic examination revealed that the left lung from both groups had marked intraalveolar edema and abundant intraalveolar neutrophils, whereas the right lung in the control group showed moderate injury and the antiinflammation group had normal pulmonary parenchyma. CONCLUSIONS Pulmonary artery perfusion using hypothermic protective solution can reduce lung injury after cardiopulmonary bypass.

Novel Strategy for Treatment of Pulmonary Arterial Hypertension: Enhancement of Apoptosis

Advanced pulmonary arterial hypertension is characterized by extensive vascular remodeling that is usually resistant to vasodilator therapy. As the major component of the vascular media, decreased apoptosis of pulmonary arterial smooth muscle cell (PASMC) plays key roles during pulmonary vascular remodeling. Recent studies showed that enhancement of apoptosis of PASMC can reverse pulmonary vascular remodeling and severe pulmonary arterial hypertension. Enhancement of apoptosis of PASMC is becoming a novel strategy to reverse severe pulmonary arterial hypertension. This review analyzes some potential strategies to reverse pulmonary vascular remodeling.

Risk Factors for Preoperative and Postoperative Progression of Aortic Regurgitation in Congenital Ruptured Sinus of Valsalva Aneurysm

BACKGROUND We reviewed our experience with congenital ruptured sinus of Valsalva aneurysms (RSVA) to determine risk factors influencing occurrence and postoperative worsening of aortic regurgitation (AR). METHODS Over an 11-year period, 210 patients (33 ± 9.7 years old) underwent surgical repair of RSVA. Aneurysm originated from the right noncoronary sinus and other sinuses in 171, 35 and 4 patients, respectively; and ruptured into right ventricle outlet tract in 115 patients, right ventricle in 16, right atrium in 75, and other chambers in 4. Aortic regurgitation (111) and ventricular septal defect (108) were common coexisting anomalies. Patch closure of RSVA was performed in 61 patients, direct sutures in 18 patients, patch closure plus direct sutures in 88 patients, and repair simultaneous with aortic valve replacement in 43 patients. RESULTS All but one patient survived the operation. In early postoperative periods, AR improved in 26 patients and worsened in 23. In 114 late follow-up patients with echocardiographic assessment, 18 showed deteriorated AR. By logistic regression analysis, RSVA ruptured into the right ventricle outlet tract and secondary changes of the aortic valve were risk factors for preoperative AR, and RSVA repaired with direct sutures had a significantly higher incidence of early worsening of AR. By Cox regression analysis, AR at discharge was an independent risk factor for late follow-up AR worsening. CONCLUSIONS The RSVA can be repaired with a low mortality and excellent long-term result. An early, aggressive treatment should be recommended to prevent postoperative AR, and a direct-suture closure of RSVA should be avoided to prevent early worsening of AR.

Lung biopsy findings in previously inoperable patients with severe pulmonary hypertension associated with congenital heart disease

BACKGROUND Congenital heart disease with near-systemic pulmonary arterial pressures, previously thought to have irreversible pulmonary vascular disease (PVD), has been successfully corrected at our institution recently. Whether the PVD is reversible remains unknown. This study aimed to examine the nature of the pulmonary arterial vessels in these selective patients. METHODS All patients with congenital heart disease and severe pulmonary hypertension (PH) were selected using Diagnostic-treatment to undergo radical repair (n=49). Lung biopsy specimens were obtained during operation. The nature of PVD was determined by Heath-Edwards classification system. All specimens were quantitatively analyzed by calculating percentage media wall area, percentage media wall thickness and arteriole density. RESULTS Transcutaneous oxygen saturation of all selected patients increased significantly after Diagnostic-treatment (P<0.001). There were no operative deaths. Mean pulmonary artery pressure and pulmonary vascular resistance regressed significantly postoperatively (P<0.001). The incidence of postoperative PH was 59.2% (29/49). Of 49 selected patients with severe PH, 38 (77.6%) showed grade I change, 5 (10.2%) showed grade II change, 4 (8.2%) showed grade III change and only 2 (4%) showed grade IV change with plexiform lesion. The percentage media wall area, percentage media wall thickness and arteriole density were significantly increased in patients associated with PH than in normal subjects (P<0.001). Follow-up data showed the reversal of PVD in these 2 patients with plexiform lesions. CONCLUSIONS The PVD in these selective patients with congenital heart disease and severe PH using a Diagnostic-treatment-and-Repair strategy is generally reversible and these patients are operable in current era.

Do Patients With Complete Transposition of the Great Arteries and Severe Pulmonary Hypertension Benefit From an Arterial Switch Operation

BACKGROUND Whether an arterial switch operation benefits patients with transposition of the great arteries and severe pulmonary hypertension (PH) remains controversial. Therefore, we evaluated the relationship between preoperative PH and early and midterm clinical outcomes after an arterial switch procedure. METHODS In this retrospective study, 101 consecutive patients with transposition of the great arteries underwent an arterial switch operation between February 2004 and October 2007. Seventy had a ventricular septal defect as well; patients with intact ventricular septum and complicated concomitant abnormities were excluded. Preoperative medical records were reviewed and mean follow-up was 22.4±15.2 months. After sternotomy, we directly measured pulmonary artery pressure before and after instituting extracorporeal circulation. Patients were divided into three groups according to mean pulmonary artery pressure (mPAP): control group (mPAP<25 mm Hg, n=23), moderate PH group (mPAP 25 to 50 mm Hg, n=37), and severe PH group (mPAP≥50 mm Hg, n=10). Early and midterm results were compared among groups. RESULTS Postoperatively, pulmonary artery pressure of both the moderate and severe PH groups decreased significantly. There were no significant differences in occurrence of postoperative complications or in-hospital mortality in the three groups (control group, 8.7%; moderate PH group, 8.1%; severe PH group, 10%; p=0.98). However, midterm mortality differed significantly (control group, 4.3%; moderate PH group, 2.7%; severe PH group, 40%; p<0.01). CONCLUSIONS Patients with transposition of the great arteries and mPAP less than 50 mm Hg can achieve satisfying results after an arterial switch operation. However, even though the operation can decrease pulmonary artery pressure, patients with preoperative mPAP greater than 50 mm Hg still suffer from high midterm mortality.

Midterm Results of Arterial Switch Operation in Older Patients With Severe Pulmonary Hypertension

BACKGROUND It is widely accepted that patients older than 6 months with dextrotransposition of the great arteries and nonrestrictive ventricular septal defect or Taussig-Bing anomaly and severe pulmonary hypertension usually are not candidates for an arterial switch operation or even repair. This study aimed to evaluate the midterm results of the arterial switch operation in these selected patients. METHODS The records of 86 patients older than 6 months with dextrotransposition of the great arteries and nonrestrictive ventricular septal defect or Taussig-Bing anomaly and severe pulmonary hypertension undergoing the arterial switch operation at our institution from 2000 to 2008 were reviewed retrospectively. Eighty survivors were followed. RESULTS There were 6 hospital deaths (7.0%, 95% confidence interval, 1.6% to 12.4%). From 2006 to 2008, 46 were operated without deaths occurring. The median duration of follow-up was 42 months. Two late deaths occurred. Latest follow-up data showed that 2.8% of survivors were in New York Heart Association class II and 97.2% in class I. CONCLUSIONS Midterm results of the arterial switch operation for patients older than 6 months with dextrotransposition of the great arteries and nonrestrictive ventricular septal defect or Taussig-Bing anomaly and severe pulmonary hypertension are excellent in the current era.

Intravascular Biocompatibility of Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate, PHBHHx) for Cardiovascular Tissue Engineering

The cDNA of Insulin-like growth factor binding protein 3 was subcloned into a eukaryotic secretory expression vector pSectagA to construct pSectag-IGFBP3. Human renal cell carcinoma (RCC) 786-0 cells were transfected with pSectag-IGFBP3 using lipofectamine 2000. After 48 h, the secretory IGFBP-3 was tested and identified by western blotting. Meanwhile, Annexin V-EGFP stain was used to analyze the apoptosis of 786-0 cells induced by IGFBP-3. Secretory IGFBP-3 protein could express successfully in the 786-0 cells and the expressed IGFBP-3 directly displayed an apoptotic effect on the host cells. This work provides a basis for further study on the apoptosis-inducing mechanism of IGFBP-3 and the development of a new anti-tumor drug.Abstract Poly (3-hydroxybutyrate-co-3-hydroxyhexanoate, PHBHHx) has superior mechanical property and biocompatibility that may enable it to meet cardiovascular tissue engineering applications. We developed hybrid materials based on decellularized xenogenic vascular scaffolds that were coated with PHBHHx to investigate the intravascular biocompatibility. The hybrid patches were implanted in the decellularized xenogenic vascular scaffolds of the rabbit abdominal aorta at 1, 4, and 12 weeks after surgery. In conclusion, PHBHHx showed remarkable intravascular biocompatibility and will benefit endothelization, which will be a useful candidate for lumen of cardiovascular tissue engineering.

A new technique for aortic valve dysfunction: reconstruction by posterior leaflet of tricuspid valve.

Valve repair for aortic dysfunction may provide an alternative approach to aortic valve replacement in selected patients. This repair by using posterior leaflet of tricuspid valve could be either an attempt at permanent correction, or palliative to avoid the use of anticoagulation and improve the anticalcification and durability of the implanted cusp. Two patients with aortic valve dysfunction underwent valve repair by this technique. The procedure included tricuspid valvuloplasty and posterior leaflet preparation, reconstruction of the aortic sinus, and posterior leaflet reimplantation to the new aortic sinus. There were no hospital deaths or other valve-related complication in either patient. Both patients had no tricuspid valve stenosis or regurgitation. Echocardiography in the first patient showed no aortic regurgitation and transvaluvular gradient of 23 mm Hg, and mild aortic insufficiency and no stenosis in the second patient. Short-term follow-up (6 months) showed no recurrent aortic dysfunction in either patient. This technique has provided satisfactory early results and could be considered an interesting corrective or palliative surgical approach.